New timing infrastructure. There's a new function schedule_timer()
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index 816d765..1d8e6b8 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -267,7 +267,13 @@ static char *ssh2_pkt_type(int pkt_ctx, int type)
     (cp)[2] = (unsigned char)((value) >> 8); \
     (cp)[3] = (unsigned char)(value); }
 
-enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
+/* Enumeration values for fields in SSH-1 packets */
+enum {
+    PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM,
+    /* These values are for communicating relevant semantics of
+     * fields to the packet logging code. */
+    PKTT_OTHER, PKTT_PASSWORD, PKTT_DATA
+};
 
 /*
  * Coroutine mechanics for the sillier bits of the code. If these
@@ -310,18 +316,24 @@ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
 #define crWaitUntilV(c)        do { crReturnV; } while (!(c))
 
 typedef struct ssh_tag *Ssh;
-
-static void ssh2_pkt_init(Ssh, int pkt_type);
-static void ssh2_pkt_addbool(Ssh, unsigned char value);
-static void ssh2_pkt_adduint32(Ssh, unsigned long value);
-static void ssh2_pkt_addstring_start(Ssh);
-static void ssh2_pkt_addstring_str(Ssh, char *data);
-static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
-static void ssh2_pkt_addstring(Ssh, char *data);
+struct Packet;
+
+static struct Packet *ssh2_pkt_init(int pkt_type);
+static void ssh2_pkt_addbool(struct Packet *, unsigned char value);
+static void ssh2_pkt_adduint32(struct Packet *, unsigned long value);
+static void ssh2_pkt_addstring_start(struct Packet *);
+static void ssh2_pkt_addstring_str(struct Packet *, char *data);
+static void ssh2_pkt_addstring_data(struct Packet *, char *data, int len);
+static void ssh2_pkt_addstring(struct Packet *, char *data);
 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len);
-static void ssh2_pkt_addmp(Ssh, Bignum b);
-static int ssh2_pkt_construct(Ssh);
-static void ssh2_pkt_send(Ssh);
+static void ssh2_pkt_addmp(struct Packet *, Bignum b);
+static int ssh2_pkt_construct(Ssh, struct Packet *);
+static void ssh2_pkt_send(Ssh, struct Packet *);
+static void ssh2_pkt_send_noqueue(Ssh, struct Packet *);
+static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
+                        struct Packet *pktin);
+static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
+                            struct Packet *pktin);
 
 /*
  * Buffer management constants. There are several of these for
@@ -452,7 +464,7 @@ struct ssh_channel {
        struct ssh_agent_channel {
            unsigned char *message;
            unsigned char msglen[4];
-           int lensofar, totallen;
+           unsigned lensofar, totallen;
        } a;
        struct ssh_x11_channel {
            Socket s;
@@ -500,14 +512,26 @@ struct ssh_rportfwd {
 struct Packet {
     long length;
     int type;
+    unsigned long sequence;
     unsigned char *data;
     unsigned char *body;
     long savedpos;
     long maxlen;
+
+    /*
+     * State associated with packet logging
+     */
+    int logmode;
+    int nblanks;
+    struct logblank_t *blanks;
 };
 
-static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
-static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
+static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen,
+                         struct Packet *pktin);
+static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen,
+                         struct Packet *pktin);
+static void ssh1_protocol_setup(Ssh ssh);
+static void ssh2_protocol_setup(Ssh ssh);
 static void ssh_size(void *handle, int width, int height);
 static void ssh_special(void *handle, Telnet_Special);
 static int ssh2_try_send(struct ssh_channel *c);
@@ -515,6 +539,10 @@ static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
 static int ssh_sendbuffer(void *handle);
+static void ssh_do_close(Ssh ssh);
+static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
+static int ssh2_pkt_getbool(struct Packet *pkt);
+static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length);
 
 struct rdpkt1_state_tag {
     long len, pad, biglen, to_read;
@@ -522,6 +550,7 @@ struct rdpkt1_state_tag {
     unsigned char *p;
     int i;
     int chunk;
+    struct Packet *pktin;
 };
 
 struct rdpkt2_state_tag {
@@ -529,8 +558,11 @@ struct rdpkt2_state_tag {
     int i;
     int cipherblk;
     unsigned long incoming_sequence;
+    struct Packet *pktin;
 };
 
+typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin);
+
 struct ssh_tag {
     const struct plug_function_table *fn;
     /* the above field _must_ be first in the structure */
@@ -570,6 +602,7 @@ struct ssh_tag {
 
     void *frontend;
 
+    int ospeed, ispeed;                       /* temporaries */
     int term_width, term_height;
 
     tree234 *channels;                /* indexed by local id */
@@ -588,8 +621,9 @@ struct ssh_tag {
 
     int size_needed, eof_needed;
 
-    struct Packet pktin;
-    struct Packet pktout;
+    struct Packet **queue;
+    int queuelen, queuesize;
+    int queueing;
     unsigned char *deferred_send_data;
     int deferred_len, deferred_size;
 
@@ -625,8 +659,8 @@ struct ssh_tag {
     int ssh2_rdpkt_crstate;
     int do_ssh_init_crstate;
     int ssh_gotdata_crstate;
-    int ssh1_protocol_crstate;
     int do_ssh1_login_crstate;
+    int do_ssh1_connection_crstate;
     int do_ssh2_transport_crstate;
     int do_ssh2_authconn_crstate;
 
@@ -638,8 +672,12 @@ struct ssh_tag {
     struct rdpkt1_state_tag rdpkt1_state;
     struct rdpkt2_state_tag rdpkt2_state;
 
-    void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
-    int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
+    /* ssh1 and ssh2 use this for different things, but both use it */
+    int protocol_initial_phase_done;
+
+    void (*protocol) (Ssh ssh, unsigned char *in, int inlen,
+                     struct Packet *pkt);
+    struct Packet *(*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
 
     /*
      * We maintain a full _copy_ of a Config structure here, not
@@ -648,12 +686,29 @@ struct ssh_tag {
      * potentially reconfigure port forwardings etc in mid-session.
      */
     Config cfg;
+
+    /*
+     * Used to transfer data back from async agent callbacks.
+     */
+    void *agent_response;
+    int agent_response_len;
+
+    /*
+     * Dispatch table for packet types that we may have to deal
+     * with at any time.
+     */
+    handler_fn_t packet_dispatch[256];
+
+    /*
+     * This module deals with sending keepalives.
+     */
+    Pinger pinger;
 };
 
 #define logevent(s) logevent(ssh->frontend, s)
 
 /* logevent, only printf-formatted. */
-static void logeventf(Ssh ssh, char *fmt, ...)
+static void logeventf(Ssh ssh, const char *fmt, ...)
 {
     va_list ap;
     char *buf;
@@ -665,9 +720,33 @@ static void logeventf(Ssh ssh, char *fmt, ...)
     sfree(buf);
 }
 
-#define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
-                          (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
-                          logeventf msg, connection_fatal msg )
+#define bombout(msg) \
+    do { \
+        char *text = dupprintf msg; \
+       ssh_do_close(ssh); \
+        logevent(text); \
+        connection_fatal(ssh->frontend, "%s", text); \
+        sfree(text); \
+    } while (0)
+
+/* Functions to leave bits out of the SSH packet log file. */
+
+static void dont_log_password(Ssh ssh, struct Packet *pkt, int blanktype)
+{
+    if (ssh->cfg.logomitpass)
+       pkt->logmode = blanktype;
+}
+
+static void dont_log_data(Ssh ssh, struct Packet *pkt, int blanktype)
+{
+    if (ssh->cfg.logomitdata)
+       pkt->logmode = blanktype;
+}
+
+static void end_log_omission(Ssh ssh, struct Packet *pkt)
+{
+    pkt->logmode = PKTLOG_EMIT;
+}
 
 static int ssh_channelcmp(void *av, void *bv)
 {
@@ -782,48 +861,69 @@ static void c_write_str(Ssh ssh, const char *buf)
     c_write(ssh, buf, strlen(buf));
 }
 
+static void ssh_free_packet(struct Packet *pkt)
+{
+    sfree(pkt->data);
+    sfree(pkt);
+}
+static struct Packet *ssh_new_packet(void)
+{
+    struct Packet *pkt = snew(struct Packet);
+
+    pkt->data = NULL;
+    pkt->maxlen = 0;
+    pkt->logmode = PKTLOG_EMIT;
+    pkt->nblanks = 0;
+    pkt->blanks = NULL;
+
+    return pkt;
+}
+
 /*
  * Collect incoming data in the incoming packet buffer.
  * Decipher and verify the packet when it is completely read.
  * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
  * Update the *data and *datalen variables.
- * Return the additional nr of bytes needed, or 0 when
- * a complete packet is available.
+ * Return a Packet structure when a packet is completed.
  */
-static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
+static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
 {
     struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
 
     crBegin(ssh->ssh1_rdpkt_crstate);
 
-  next_packet:
+    st->pktin = ssh_new_packet();
 
-    ssh->pktin.type = 0;
-    ssh->pktin.length = 0;
+    st->pktin->type = 0;
+    st->pktin->length = 0;
 
     for (st->i = st->len = 0; st->i < 4; st->i++) {
        while ((*datalen) == 0)
-           crReturn(4 - st->i);
+           crReturn(NULL);
        st->len = (st->len << 8) + **data;
        (*data)++, (*datalen)--;
     }
 
     st->pad = 8 - (st->len % 8);
     st->biglen = st->len + st->pad;
-    ssh->pktin.length = st->len - 5;
+    st->pktin->length = st->len - 5;
 
-    if (ssh->pktin.maxlen < st->biglen) {
-       ssh->pktin.maxlen = st->biglen;
-       ssh->pktin.data = sresize(ssh->pktin.data, st->biglen + APIEXTRA,
-                                 unsigned char);
+    if (st->biglen < 0) {
+        bombout(("Extremely large packet length from server suggests"
+                " data stream corruption"));
+       ssh_free_packet(st->pktin);
+        crStop(NULL);
     }
 
+    st->pktin->maxlen = st->biglen;
+    st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char);
+
     st->to_read = st->biglen;
-    st->p = ssh->pktin.data;
+    st->p = st->pktin->data;
     while (st->to_read > 0) {
        st->chunk = st->to_read;
        while ((*datalen) == 0)
-           crReturn(st->to_read);
+           crReturn(NULL);
        if (st->chunk > (*datalen))
            st->chunk = (*datalen);
        memcpy(st->p, *data, st->chunk);
@@ -833,108 +933,95 @@ static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
        st->to_read -= st->chunk;
     }
 
-    if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
+    if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data,
                                     st->biglen, NULL)) {
-        bombout((ssh,"Network attack (CRC compensation) detected!"));
-        crReturn(0);
+        bombout(("Network attack (CRC compensation) detected!"));
+       ssh_free_packet(st->pktin);
+        crStop(NULL);
     }
 
     if (ssh->cipher)
-       ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
+       ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen);
 
-    st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
-    st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
+    st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4);
+    st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4);
     if (st->gotcrc != st->realcrc) {
-       bombout((ssh,"Incorrect CRC received on packet"));
-       crReturn(0);
+       bombout(("Incorrect CRC received on packet"));
+       ssh_free_packet(st->pktin);
+       crStop(NULL);
     }
 
-    ssh->pktin.body = ssh->pktin.data + st->pad + 1;
+    st->pktin->body = st->pktin->data + st->pad + 1;
+    st->pktin->savedpos = 0;
 
     if (ssh->v1_compressing) {
        unsigned char *decompblk;
        int decomplen;
-       zlib_decompress_block(ssh->sc_comp_ctx,
-                             ssh->pktin.body - 1, ssh->pktin.length + 1,
-                             &decompblk, &decomplen);
-
-       if (ssh->pktin.maxlen < st->pad + decomplen) {
-           ssh->pktin.maxlen = st->pad + decomplen;
-           ssh->pktin.data = sresize(ssh->pktin.data,
-                                     ssh->pktin.maxlen + APIEXTRA,
+       if (!zlib_decompress_block(ssh->sc_comp_ctx,
+                                  st->pktin->body - 1, st->pktin->length + 1,
+                                  &decompblk, &decomplen)) {
+           bombout(("Zlib decompression encountered invalid data"));
+           ssh_free_packet(st->pktin);
+           crStop(NULL);
+       }
+
+       if (st->pktin->maxlen < st->pad + decomplen) {
+           st->pktin->maxlen = st->pad + decomplen;
+           st->pktin->data = sresize(st->pktin->data,
+                                     st->pktin->maxlen + APIEXTRA,
                                      unsigned char);
-           ssh->pktin.body = ssh->pktin.data + st->pad + 1;
+           st->pktin->body = st->pktin->data + st->pad + 1;
        }
 
-       memcpy(ssh->pktin.body - 1, decompblk, decomplen);
+       memcpy(st->pktin->body - 1, decompblk, decomplen);
        sfree(decompblk);
-       ssh->pktin.length = decomplen - 1;
+       st->pktin->length = decomplen - 1;
     }
 
-    ssh->pktin.type = ssh->pktin.body[-1];
+    st->pktin->type = st->pktin->body[-1];
 
-    if (ssh->logctx)
-       log_packet(ssh->logctx,
-                  PKT_INCOMING, ssh->pktin.type,
-                  ssh1_pkt_type(ssh->pktin.type),
-                  ssh->pktin.body, ssh->pktin.length);
-
-    if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
-       ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
-       ssh->pktin.type == SSH1_MSG_DEBUG ||
-       ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
-       ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
-       long stringlen = GET_32BIT(ssh->pktin.body);
-       if (stringlen + 4 != ssh->pktin.length) {
-           bombout((ssh,"Received data packet with bogus string length"));
-           crReturn(0);
+    /*
+     * Log incoming packet, possibly omitting sensitive fields.
+     */
+    if (ssh->logctx) {
+       int nblanks = 0;
+       struct logblank_t blank;
+       if (ssh->cfg.logomitdata) {
+           int do_blank = FALSE, blank_prefix = 0;
+           /* "Session data" packets - omit the data field */
+           if ((st->pktin->type == SSH1_SMSG_STDOUT_DATA) ||
+               (st->pktin->type == SSH1_SMSG_STDERR_DATA)) {
+               do_blank = TRUE; blank_prefix = 0;
+           } else if (st->pktin->type == SSH1_MSG_CHANNEL_DATA) {
+               do_blank = TRUE; blank_prefix = 4;
+           }
+           if (do_blank) {
+               blank.offset = blank_prefix;
+               blank.len = st->pktin->length;
+               blank.type = PKTLOG_OMIT;
+               nblanks = 1;
+           }
        }
+       log_packet(ssh->logctx,
+                  PKT_INCOMING, st->pktin->type,
+                  ssh1_pkt_type(st->pktin->type),
+                  st->pktin->body, st->pktin->length,
+                  nblanks, &blank);
     }
 
-    if (ssh->pktin.type == SSH1_MSG_DEBUG) {
-       /* log debug message */
-       char buf[512];
-       int stringlen = GET_32BIT(ssh->pktin.body);
-       strcpy(buf, "Remote debug message: ");
-       if (stringlen > 480)
-           stringlen = 480;
-       memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
-       buf[8 + stringlen] = '\0';
-       logevent(buf);
-       goto next_packet;
-    } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
-       /* do nothing */
-       goto next_packet;
-    }
-
-    if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
-       /* log reason code in disconnect message */
-       char buf[256];
-       unsigned msglen = GET_32BIT(ssh->pktin.body);
-       unsigned nowlen;
-       strcpy(buf, "Remote sent disconnect: ");
-       nowlen = strlen(buf);
-       if (msglen > sizeof(buf) - nowlen - 1)
-           msglen = sizeof(buf) - nowlen - 1;
-       memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
-       buf[nowlen + msglen] = '\0';
-       /* logevent(buf); (this is now done within the bombout macro) */
-       bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
-       crReturn(0);
-    }
-
-    crFinish(0);
+    crFinish(st->pktin);
 }
 
-static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
+static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
 {
     struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
 
     crBegin(ssh->ssh2_rdpkt_crstate);
 
-  next_packet:
-    ssh->pktin.type = 0;
-    ssh->pktin.length = 0;
+    st->pktin = ssh_new_packet();
+
+    st->pktin->type = 0;
+    st->pktin->length = 0;
     if (ssh->sccipher)
        st->cipherblk = ssh->sccipher->blksize;
     else
@@ -942,11 +1029,7 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
     if (st->cipherblk < 8)
        st->cipherblk = 8;
 
-    if (ssh->pktin.maxlen < st->cipherblk) {
-       ssh->pktin.maxlen = st->cipherblk;
-       ssh->pktin.data = sresize(ssh->pktin.data, st->cipherblk + APIEXTRA,
-                                 unsigned char);
-    }
+    st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char);
 
     /*
      * Acquire and decrypt the first block of the packet. This will
@@ -954,28 +1037,29 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
      */
     for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
        while ((*datalen) == 0)
-           crReturn(st->cipherblk - st->i);
-       ssh->pktin.data[st->i] = *(*data)++;
+           crReturn(NULL);
+       st->pktin->data[st->i] = *(*data)++;
        (*datalen)--;
     }
 
     if (ssh->sccipher)
        ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
-                              ssh->pktin.data, st->cipherblk);
+                              st->pktin->data, st->cipherblk);
 
     /*
      * Now get the length and padding figures.
      */
-    st->len = GET_32BIT(ssh->pktin.data);
-    st->pad = ssh->pktin.data[4];
+    st->len = GET_32BIT(st->pktin->data);
+    st->pad = st->pktin->data[4];
 
     /*
      * _Completely_ silly lengths should be stomped on before they
      * do us any more damage.
      */
     if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
-       bombout((ssh,"Incoming packet was garbled on decryption"));
-       crReturn(0);
+       bombout(("Incoming packet was garbled on decryption"));
+       ssh_free_packet(st->pktin);
+       crStop(NULL);
     }
 
     /*
@@ -983,7 +1067,7 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
      */
     st->payload = st->len - st->pad - 1;
 
-    ssh->pktin.length = st->payload + 5;
+    st->pktin->length = st->payload + 5;
 
     /*
      * So now we can work out the total packet length.
@@ -992,14 +1076,12 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
     st->maclen = ssh->scmac ? ssh->scmac->len : 0;
 
     /*
-     * Adjust memory allocation if packet is too big.
+     * Allocate memory for the rest of the packet.
      */
-    if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
-       ssh->pktin.maxlen = st->packetlen + st->maclen;
-       ssh->pktin.data = sresize(ssh->pktin.data,
-                                 ssh->pktin.maxlen + APIEXTRA,
-                                 unsigned char);
-    }
+    st->pktin->maxlen = st->packetlen + st->maclen;
+    st->pktin->data = sresize(st->pktin->data,
+                             st->pktin->maxlen + APIEXTRA,
+                             unsigned char);
 
     /*
      * Read and decrypt the remainder of the packet.
@@ -1007,26 +1089,28 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
     for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
         st->i++) {
        while ((*datalen) == 0)
-           crReturn(st->packetlen + st->maclen - st->i);
-       ssh->pktin.data[st->i] = *(*data)++;
+           crReturn(NULL);
+       st->pktin->data[st->i] = *(*data)++;
        (*datalen)--;
     }
     /* Decrypt everything _except_ the MAC. */
     if (ssh->sccipher)
        ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
-                              ssh->pktin.data + st->cipherblk,
+                              st->pktin->data + st->cipherblk,
                               st->packetlen - st->cipherblk);
 
     /*
      * Check the MAC.
      */
     if (ssh->scmac
-       && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
+       && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data, st->len + 4,
                               st->incoming_sequence)) {
-       bombout((ssh,"Incorrect MAC received on packet"));
-       crReturn(0);
+       bombout(("Incorrect MAC received on packet"));
+       ssh_free_packet(st->pktin);
+       crStop(NULL);
     }
-    st->incoming_sequence++;          /* whether or not we MACed */
+
+    st->pktin->sequence = st->incoming_sequence++;
 
     /*
      * Decompress packet payload.
@@ -1036,132 +1120,55 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
        int newlen;
        if (ssh->sccomp &&
            ssh->sccomp->decompress(ssh->sc_comp_ctx,
-                                   ssh->pktin.data + 5, ssh->pktin.length - 5,
+                                   st->pktin->data + 5, st->pktin->length - 5,
                                    &newpayload, &newlen)) {
-           if (ssh->pktin.maxlen < newlen + 5) {
-               ssh->pktin.maxlen = newlen + 5;
-               ssh->pktin.data = sresize(ssh->pktin.data,
-                                         ssh->pktin.maxlen + APIEXTRA,
+           if (st->pktin->maxlen < newlen + 5) {
+               st->pktin->maxlen = newlen + 5;
+               st->pktin->data = sresize(st->pktin->data,
+                                         st->pktin->maxlen + APIEXTRA,
                                          unsigned char);
            }
-           ssh->pktin.length = 5 + newlen;
-           memcpy(ssh->pktin.data + 5, newpayload, newlen);
+           st->pktin->length = 5 + newlen;
+           memcpy(st->pktin->data + 5, newpayload, newlen);
            sfree(newpayload);
        }
     }
 
-    ssh->pktin.savedpos = 6;
-    ssh->pktin.type = ssh->pktin.data[5];
+    st->pktin->savedpos = 6;
+    st->pktin->body = st->pktin->data;
+    st->pktin->type = st->pktin->data[5];
 
-    if (ssh->logctx)
-       log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
-                  ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
-                  ssh->pktin.data+6, ssh->pktin.length-6);
-
-    switch (ssh->pktin.type) {
-        /*
-         * These packets we must handle instantly.
-         */
-      case SSH2_MSG_DISCONNECT:
-        {
-            /* log reason code in disconnect message */
-            char *buf;
-           int nowlen;
-            int reason = GET_32BIT(ssh->pktin.data + 6);
-            unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
-
-            if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
-                buf = dupprintf("Received disconnect message (%s)",
-                               ssh2_disconnect_reasons[reason]);
-            } else {
-                buf = dupprintf("Received disconnect message (unknown"
-                               " type %d)", reason);
-            }
-            logevent(buf);
-           sfree(buf);
-            buf = dupprintf("Disconnection message text: %n%.*s",
-                           &nowlen, msglen, ssh->pktin.data + 14);
-            logevent(buf);
-            bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
-                     reason,
-                     (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
-                     ssh2_disconnect_reasons[reason] : "unknown",
-                     buf+nowlen));
-           sfree(buf);
-            crReturn(0);
-        }
-        break;
-      case SSH2_MSG_IGNORE:
-       goto next_packet;
-      case SSH2_MSG_DEBUG:
-       {
-           /* log the debug message */
-           char buf[512];
-           /* int display = ssh->pktin.body[6]; */
-           int stringlen = GET_32BIT(ssh->pktin.data+7);
-           int prefix;
-           strcpy(buf, "Remote debug message: ");
-           prefix = strlen(buf);
-           if (stringlen > (int)(sizeof(buf)-prefix-1))
-               stringlen = sizeof(buf)-prefix-1;
-           memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
-           buf[prefix + stringlen] = '\0';
-           logevent(buf);
+    /*
+     * Log incoming packet, possibly omitting sensitive fields.
+     */
+    if (ssh->logctx) {
+       int nblanks = 0;
+       struct logblank_t blank;
+       if (ssh->cfg.logomitdata) {
+           int do_blank = FALSE, blank_prefix = 0;
+           /* "Session data" packets - omit the data field */
+           if (st->pktin->type == SSH2_MSG_CHANNEL_DATA) {
+               do_blank = TRUE; blank_prefix = 4;
+           } else if (st->pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
+               do_blank = TRUE; blank_prefix = 8;
+           }
+           if (do_blank) {
+               blank.offset = blank_prefix;
+               blank.len = (st->pktin->length-6) - blank_prefix;
+               blank.type = PKTLOG_OMIT;
+               nblanks = 1;
+           }
        }
-        goto next_packet;              /* FIXME: print the debug message */
-
-        /*
-         * These packets we need do nothing about here.
-         */
-      case SSH2_MSG_UNIMPLEMENTED:
-      case SSH2_MSG_SERVICE_REQUEST:
-      case SSH2_MSG_SERVICE_ACCEPT:
-      case SSH2_MSG_KEXINIT:
-      case SSH2_MSG_NEWKEYS:
-      case SSH2_MSG_KEXDH_INIT:
-      case SSH2_MSG_KEXDH_REPLY:
-      /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
-      /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
-      case SSH2_MSG_KEX_DH_GEX_INIT:
-      case SSH2_MSG_KEX_DH_GEX_REPLY:
-      case SSH2_MSG_USERAUTH_REQUEST:
-      case SSH2_MSG_USERAUTH_FAILURE:
-      case SSH2_MSG_USERAUTH_SUCCESS:
-      case SSH2_MSG_USERAUTH_BANNER:
-      case SSH2_MSG_USERAUTH_PK_OK:
-      /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
-      /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
-      case SSH2_MSG_USERAUTH_INFO_RESPONSE:
-      case SSH2_MSG_GLOBAL_REQUEST:
-      case SSH2_MSG_REQUEST_SUCCESS:
-      case SSH2_MSG_REQUEST_FAILURE:
-      case SSH2_MSG_CHANNEL_OPEN:
-      case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
-      case SSH2_MSG_CHANNEL_OPEN_FAILURE:
-      case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
-      case SSH2_MSG_CHANNEL_DATA:
-      case SSH2_MSG_CHANNEL_EXTENDED_DATA:
-      case SSH2_MSG_CHANNEL_EOF:
-      case SSH2_MSG_CHANNEL_CLOSE:
-      case SSH2_MSG_CHANNEL_REQUEST:
-      case SSH2_MSG_CHANNEL_SUCCESS:
-      case SSH2_MSG_CHANNEL_FAILURE:
-        break;
-
-        /*
-         * For anything else we send SSH2_MSG_UNIMPLEMENTED.
-         */
-      default:
-       ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
-       ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
-       ssh2_pkt_send(ssh);
-        break;
+       log_packet(ssh->logctx, PKT_INCOMING, st->pktin->type,
+                  ssh2_pkt_type(ssh->pkt_ctx, st->pktin->type),
+                  st->pktin->data+6, st->pktin->length-6,
+                  nblanks, &blank);
     }
 
-    crFinish(0);
+    crFinish(st->pktin);
 }
 
-static void ssh1_pktout_size(Ssh ssh, int len)
+static void ssh1_pktout_size(struct Packet *pkt, int len)
 {
     int pad, biglen;
 
@@ -1169,29 +1176,26 @@ static void ssh1_pktout_size(Ssh ssh, int len)
     pad = 8 - (len % 8);
     biglen = len + pad;
 
-    ssh->pktout.length = len - 5;
-    if (ssh->pktout.maxlen < biglen) {
-       ssh->pktout.maxlen = biglen;
-#ifdef MSCRYPTOAPI
-       /* Allocate enough buffer space for extra block
-        * for MS CryptEncrypt() */
-       ssh->pktout.data = sresize(ssh->pktout.data, biglen + 12,
-                                  unsigned char);
-#else
-       ssh->pktout.data = sresize(ssh->pktout.data, biglen + 4,
-                                  unsigned char);
-#endif
+    pkt->length = len - 5;
+    if (pkt->maxlen < biglen) {
+       pkt->maxlen = biglen;
+       pkt->data = sresize(pkt->data, biglen + 4 + APIEXTRA, unsigned char);
     }
-    ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
+    pkt->body = pkt->data + 4 + pad + 1;
 }
 
-static void s_wrpkt_start(Ssh ssh, int type, int len)
+static struct Packet *s_wrpkt_start(int type, int len)
 {
-    ssh1_pktout_size(ssh, len);
-    ssh->pktout.type = type;
+    struct Packet *pkt = ssh_new_packet();
+    ssh1_pktout_size(pkt, len);
+    pkt->type = type;
+    /* Initialise log omission state */
+    pkt->nblanks = 0;
+    pkt->blanks = NULL;
+    return pkt;
 }
 
-static int s_wrpkt_prepare(Ssh ssh)
+static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt)
 {
     int pad, biglen, i;
     unsigned long crc;
@@ -1206,72 +1210,77 @@ static int s_wrpkt_prepare(Ssh ssh)
 #endif
     int len;
 
-    ssh->pktout.body[-1] = ssh->pktout.type;
+    pkt->body[-1] = pkt->type;
 
     if (ssh->logctx)
-       log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
-                  ssh1_pkt_type(ssh->pktout.type),
-                  ssh->pktout.body, ssh->pktout.length);
+       log_packet(ssh->logctx, PKT_OUTGOING, pkt->type,
+                  ssh1_pkt_type(pkt->type),
+                  pkt->body, pkt->length,
+                  pkt->nblanks, pkt->blanks);
+    sfree(pkt->blanks); pkt->blanks = NULL;
+    pkt->nblanks = 0;
 
     if (ssh->v1_compressing) {
        unsigned char *compblk;
        int complen;
        zlib_compress_block(ssh->cs_comp_ctx,
-                           ssh->pktout.body - 1, ssh->pktout.length + 1,
+                           pkt->body - 1, pkt->length + 1,
                            &compblk, &complen);
-       ssh1_pktout_size(ssh, complen - 1);
-       memcpy(ssh->pktout.body - 1, compblk, complen);
+       ssh1_pktout_size(pkt, complen - 1);
+       memcpy(pkt->body - 1, compblk, complen);
        sfree(compblk);
     }
 
-    len = ssh->pktout.length + 5;             /* type and CRC */
+    len = pkt->length + 5;            /* type and CRC */
     pad = 8 - (len % 8);
     biglen = len + pad;
 
     for (i = 0; i < pad; i++)
-       ssh->pktout.data[i + 4] = random_byte();
-    crc = crc32(ssh->pktout.data + 4, biglen - 4);
-    PUT_32BIT(ssh->pktout.data + biglen, crc);
-    PUT_32BIT(ssh->pktout.data, len);
+       pkt->data[i + 4] = random_byte();
+    crc = crc32_compute(pkt->data + 4, biglen - 4);
+    PUT_32BIT(pkt->data + biglen, crc);
+    PUT_32BIT(pkt->data, len);
 
     if (ssh->cipher)
-       ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
+       ssh->cipher->encrypt(ssh->v1_cipher_ctx, pkt->data + 4, biglen);
 
     return biglen + 4;
 }
 
-static void s_wrpkt(Ssh ssh)
+static void s_wrpkt(Ssh ssh, struct Packet *pkt)
 {
     int len, backlog;
-    len = s_wrpkt_prepare(ssh);
-    backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
+    len = s_wrpkt_prepare(ssh, pkt);
+    backlog = sk_write(ssh->s, (char *)pkt->data, len);
     if (backlog > SSH_MAX_BACKLOG)
        ssh_throttle_all(ssh, 1, backlog);
 }
 
-static void s_wrpkt_defer(Ssh ssh)
+static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt)
 {
     int len;
-    len = s_wrpkt_prepare(ssh);
+    len = s_wrpkt_prepare(ssh, pkt);
     if (ssh->deferred_len + len > ssh->deferred_size) {
        ssh->deferred_size = ssh->deferred_len + len + 128;
        ssh->deferred_send_data = sresize(ssh->deferred_send_data,
                                          ssh->deferred_size,
                                          unsigned char);
     }
-    memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
+    memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->data, len);
     ssh->deferred_len += len;
 }
 
 /*
  * Construct a packet with the specified contents.
  */
-static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
+static struct Packet *construct_packet(Ssh ssh, int pkttype,
+                                      va_list ap1, va_list ap2)
 {
     unsigned char *p, *argp, argchar;
     unsigned long argint;
     int pktlen, argtype, arglen;
     Bignum bn;
+    struct Packet *pkt;
 
     pktlen = 0;
     while ((argtype = va_arg(ap1, int)) != PKT_END) {
@@ -1298,63 +1307,100 @@ static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
            bn = va_arg(ap1, Bignum);
            pktlen += ssh1_bignum_length(bn);
            break;
+         case PKTT_PASSWORD:
+         case PKTT_DATA:
+         case PKTT_OTHER:
+           /* ignore this pass */
+           break;
          default:
            assert(0);
        }
     }
 
-    s_wrpkt_start(ssh, pkttype, pktlen);
-    p = ssh->pktout.body;
+    pkt = s_wrpkt_start(pkttype, pktlen);
+    p = pkt->body;
 
     while ((argtype = va_arg(ap2, int)) != PKT_END) {
+       int offset = p - pkt->body, len = 0;
        switch (argtype) {
+         /* Actual fields in the packet */
          case PKT_INT:
            argint = va_arg(ap2, int);
            PUT_32BIT(p, argint);
-           p += 4;
+           len = 4;
            break;
          case PKT_CHAR:
            argchar = (unsigned char) va_arg(ap2, int);
            *p = argchar;
-           p++;
+           len = 1;
            break;
          case PKT_DATA:
            argp = va_arg(ap2, unsigned char *);
            arglen = va_arg(ap2, int);
            memcpy(p, argp, arglen);
-           p += arglen;
+           len = arglen;
            break;
          case PKT_STR:
            argp = va_arg(ap2, unsigned char *);
            arglen = strlen((char *)argp);
            PUT_32BIT(p, arglen);
            memcpy(p + 4, argp, arglen);
-           p += 4 + arglen;
+           len = arglen + 4;
            break;
          case PKT_BIGNUM:
            bn = va_arg(ap2, Bignum);
-           p += ssh1_write_bignum(p, bn);
+           len = ssh1_write_bignum(p, bn);
            break;
+         /* Tokens for modifications to packet logging */
+         case PKTT_PASSWORD:
+           dont_log_password(ssh, pkt, PKTLOG_BLANK);
+           break;
+         case PKTT_DATA:
+           dont_log_data(ssh, pkt, PKTLOG_OMIT);
+           break;
+         case PKTT_OTHER:
+           end_log_omission(ssh, pkt);
+           break;
+       }
+       p += len;
+       /* Deal with logfile omission, if required. */
+       if (len && (pkt->logmode != PKTLOG_EMIT)) {
+           pkt->nblanks++;
+           pkt->blanks = sresize(pkt->blanks, pkt->nblanks,
+                                 struct logblank_t);
+           pkt->blanks[pkt->nblanks-1].offset = offset;
+           pkt->blanks[pkt->nblanks-1].len    = len;
+           pkt->blanks[pkt->nblanks-1].type   = pkt->logmode;
        }
     }
+
+    return pkt;
 }
 
 static void send_packet(Ssh ssh, int pkttype, ...)
 {
+    struct Packet *pkt;
     va_list ap1, ap2;
     va_start(ap1, pkttype);
     va_start(ap2, pkttype);
-    construct_packet(ssh, pkttype, ap1, ap2);
-    s_wrpkt(ssh);
+    pkt = construct_packet(ssh, pkttype, ap1, ap2);
+    va_end(ap2);
+    va_end(ap1);
+    s_wrpkt(ssh, pkt);
+    ssh_free_packet(pkt);
 }
 
 static void defer_packet(Ssh ssh, int pkttype, ...)
 {
+    struct Packet *pkt;
     va_list ap1, ap2;
     va_start(ap1, pkttype);
     va_start(ap2, pkttype);
-    construct_packet(ssh, pkttype, ap1, ap2);
-    s_wrpkt_defer(ssh);
+    pkt = construct_packet(ssh, pkttype, ap1, ap2);
+    va_end(ap2);
+    va_end(ap1);
+    s_wrpkt_defer(ssh, pkt);
+    ssh_free_packet(pkt);
 }
 
 static int ssh_versioncmp(char *a, char *b)
@@ -1400,63 +1446,66 @@ static void sha_uint32(SHA_State * s, unsigned i)
 /*
  * SSH2 packet construction functions.
  */
-static void ssh2_pkt_ensure(Ssh ssh, int length)
+static void ssh2_pkt_ensure(struct Packet *pkt, int length)
 {
-    if (ssh->pktout.maxlen < length) {
-       ssh->pktout.maxlen = length + 256;
-       ssh->pktout.data = sresize(ssh->pktout.data,
-                                  ssh->pktout.maxlen + APIEXTRA,
-                                  unsigned char);
-       if (!ssh->pktout.data)
-           fatalbox("Out of memory");
+    if (pkt->maxlen < length) {
+       pkt->maxlen = length + 256;
+       pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char);
     }
 }
-static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
+static void ssh2_pkt_adddata(struct Packet *pkt, void *data, int len)
 {
-    ssh->pktout.length += len;
-    ssh2_pkt_ensure(ssh, ssh->pktout.length);
-    memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
+    if (pkt->logmode != PKTLOG_EMIT) {
+       pkt->nblanks++;
+       pkt->blanks = sresize(pkt->blanks, pkt->nblanks, struct logblank_t);
+       pkt->blanks[pkt->nblanks-1].offset = pkt->length - 6;
+       pkt->blanks[pkt->nblanks-1].len = len;
+       pkt->blanks[pkt->nblanks-1].type = pkt->logmode;
+    }
+    pkt->length += len;
+    ssh2_pkt_ensure(pkt, pkt->length);
+    memcpy(pkt->data + pkt->length - len, data, len);
 }
-static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
+static void ssh2_pkt_addbyte(struct Packet *pkt, unsigned char byte)
 {
-    ssh2_pkt_adddata(ssh, &byte, 1);
+    ssh2_pkt_adddata(pkt, &byte, 1);
 }
-static void ssh2_pkt_init(Ssh ssh, int pkt_type)
+static struct Packet *ssh2_pkt_init(int pkt_type)
 {
-    ssh->pktout.length = 5;
-    ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
+    struct Packet *pkt = ssh_new_packet();
+    pkt->length = 5;
+    ssh2_pkt_addbyte(pkt, (unsigned char) pkt_type);
+    return pkt;
 }
-static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
+static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value)
 {
-    ssh2_pkt_adddata(ssh, &value, 1);
+    ssh2_pkt_adddata(pkt, &value, 1);
 }
-static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
+static void ssh2_pkt_adduint32(struct Packet *pkt, unsigned long value)
 {
     unsigned char x[4];
     PUT_32BIT(x, value);
-    ssh2_pkt_adddata(ssh, x, 4);
+    ssh2_pkt_adddata(pkt, x, 4);
 }
-static void ssh2_pkt_addstring_start(Ssh ssh)
+static void ssh2_pkt_addstring_start(struct Packet *pkt)
 {
-    ssh2_pkt_adduint32(ssh, 0);
-    ssh->pktout.savedpos = ssh->pktout.length;
+    ssh2_pkt_adduint32(pkt, 0);
+    pkt->savedpos = pkt->length;
 }
-static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
+static void ssh2_pkt_addstring_str(struct Packet *pkt, char *data)
 {
-    ssh2_pkt_adddata(ssh, data, strlen(data));
-    PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
-             ssh->pktout.length - ssh->pktout.savedpos);
+    ssh2_pkt_adddata(pkt, data, strlen(data));
+    PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
 }
-static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
+static void ssh2_pkt_addstring_data(struct Packet *pkt, char *data, int len)
 {
-    ssh2_pkt_adddata(ssh, data, len);
-    PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
-             ssh->pktout.length - ssh->pktout.savedpos);
+    ssh2_pkt_adddata(pkt, data, len);
+    PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos);
 }
-static void ssh2_pkt_addstring(Ssh ssh, char *data)
+static void ssh2_pkt_addstring(struct Packet *pkt, char *data)
 {
-    ssh2_pkt_addstring_start(ssh);
-    ssh2_pkt_addstring_str(ssh, data);
+    ssh2_pkt_addstring_start(pkt);
+    ssh2_pkt_addstring_str(pkt, data);
 }
 static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
 {
@@ -1475,29 +1524,32 @@ static unsigned char *ssh2_mpint_fmt(Bignum b, int *len)
     *len = n + 1 - i;
     return p;
 }
-static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
+static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b)
 {
     unsigned char *p;
     int len;
     p = ssh2_mpint_fmt(b, &len);
-    ssh2_pkt_addstring_start(ssh);
-    ssh2_pkt_addstring_data(ssh, (char *)p, len);
+    ssh2_pkt_addstring_start(pkt);
+    ssh2_pkt_addstring_data(pkt, (char *)p, len);
     sfree(p);
 }
 
 /*
  * Construct an SSH2 final-form packet: compress it, encrypt it,
  * put the MAC on it. Final packet, ready to be sent, is stored in
- * ssh->pktout.data. Total length is returned.
+ * pkt->data. Total length is returned.
  */
-static int ssh2_pkt_construct(Ssh ssh)
+static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
 {
     int cipherblk, maclen, padding, i;
 
     if (ssh->logctx)
-       log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
-                  ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
-                  ssh->pktout.data + 6, ssh->pktout.length - 6);
+       log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
+                  ssh2_pkt_type(ssh->pkt_ctx, pkt->data[5]),
+                  pkt->data + 6, pkt->length - 6,
+                  pkt->nblanks, pkt->blanks);
+    sfree(pkt->blanks); pkt->blanks = NULL;
+    pkt->nblanks = 0;
 
     /*
      * Compress packet payload.
@@ -1506,11 +1558,11 @@ static int ssh2_pkt_construct(Ssh ssh)
        unsigned char *newpayload;
        int newlen;
        if (ssh->cscomp &&
-           ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
-                                 ssh->pktout.length - 5,
+           ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5,
+                                 pkt->length - 5,
                                  &newpayload, &newlen)) {
-           ssh->pktout.length = 5;
-           ssh2_pkt_adddata(ssh, newpayload, newlen);
+           pkt->length = 5;
+           ssh2_pkt_adddata(pkt, newpayload, newlen);
            sfree(newpayload);
        }
     }
@@ -1523,67 +1575,138 @@ static int ssh2_pkt_construct(Ssh ssh)
     cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
     padding = 4;
     padding +=
-       (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
+       (cipherblk - (pkt->length + padding) % cipherblk) % cipherblk;
     maclen = ssh->csmac ? ssh->csmac->len : 0;
-    ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
-    ssh->pktout.data[4] = padding;
+    ssh2_pkt_ensure(pkt, pkt->length + padding + maclen);
+    pkt->data[4] = padding;
     for (i = 0; i < padding; i++)
-       ssh->pktout.data[ssh->pktout.length + i] = random_byte();
-    PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
+       pkt->data[pkt->length + i] = random_byte();
+    PUT_32BIT(pkt->data, pkt->length + padding - 4);
     if (ssh->csmac)
-       ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
-                            ssh->pktout.length + padding,
+       ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data,
+                            pkt->length + padding,
                             ssh->v2_outgoing_sequence);
     ssh->v2_outgoing_sequence++;       /* whether or not we MACed */
 
     if (ssh->cscipher)
        ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
-                              ssh->pktout.data, ssh->pktout.length + padding);
+                              pkt->data, pkt->length + padding);
 
-    /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
-    return ssh->pktout.length + padding + maclen;
+    /* Ready-to-send packet starts at pkt->data. We return length. */
+    return pkt->length + padding + maclen;
 }
 
 /*
- * Construct and send an SSH2 packet immediately.
+ * Routines called from the main SSH code to send packets. There
+ * are quite a few of these, because we have two separate
+ * mechanisms for delaying the sending of packets:
+ * 
+ *  - In order to send an IGNORE message and a password message in
+ *    a single fixed-length blob, we require the ability to
+ *    concatenate the encrypted forms of those two packets _into_ a
+ *    single blob and then pass it to our <network.h> transport
+ *    layer in one go. Hence, there's a deferment mechanism which
+ *    works after packet encryption.
+ * 
+ *  - In order to avoid sending any connection-layer messages
+ *    during repeat key exchange, we have to queue up any such
+ *    outgoing messages _before_ they are encrypted (and in
+ *    particular before they're allocated sequence numbers), and
+ *    then send them once we've finished.
+ * 
+ * I call these mechanisms `defer' and `queue' respectively, so as
+ * to distinguish them reasonably easily.
+ * 
+ * The functions send_noqueue() and defer_noqueue() free the packet
+ * structure they are passed. Every outgoing packet goes through
+ * precisely one of these functions in its life; packets passed to
+ * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of
+ * these or get queued, and then when the queue is later emptied
+ * the packets are all passed to defer_noqueue().
+ */
+
+/*
+ * Send an SSH2 packet immediately, without queuing or deferring.
  */
-static void ssh2_pkt_send(Ssh ssh)
+static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt)
 {
     int len;
     int backlog;
-    len = ssh2_pkt_construct(ssh);
-    backlog = sk_write(ssh->s, (char *)ssh->pktout.data, len);
+    len = ssh2_pkt_construct(ssh, pkt);
+    backlog = sk_write(ssh->s, (char *)pkt->data, len);
     if (backlog > SSH_MAX_BACKLOG)
        ssh_throttle_all(ssh, 1, backlog);
+    ssh_free_packet(pkt);
 }
 
 /*
- * Construct an SSH2 packet and add it to a deferred data block.
- * Useful for sending multiple packets in a single sk_write() call,
- * to prevent a traffic-analysing listener from being able to work
- * out the length of any particular packet (such as the password
- * packet).
- * 
- * Note that because SSH2 sequence-numbers its packets, this can
- * NOT be used as an m4-style `defer' allowing packets to be
- * constructed in one order and sent in another.
+ * Defer an SSH2 packet.
  */
-static void ssh2_pkt_defer(Ssh ssh)
+static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt)
 {
-    int len = ssh2_pkt_construct(ssh);
+    int len = ssh2_pkt_construct(ssh, pkt);
     if (ssh->deferred_len + len > ssh->deferred_size) {
        ssh->deferred_size = ssh->deferred_len + len + 128;
        ssh->deferred_send_data = sresize(ssh->deferred_send_data,
                                          ssh->deferred_size,
                                          unsigned char);
     }
-    memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
+    memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->data, len);
     ssh->deferred_len += len;
+    ssh_free_packet(pkt);
+}
+
+/*
+ * Queue an SSH2 packet.
+ */
+static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt)
+{
+    assert(ssh->queueing);
+
+    if (ssh->queuelen >= ssh->queuesize) {
+       ssh->queuesize = ssh->queuelen + 32;
+       ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *);
+    }
+
+    ssh->queue[ssh->queuelen++] = pkt;
+}
+
+/*
+ * Either queue or send a packet, depending on whether queueing is
+ * set.
+ */
+static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt)
+{
+    if (ssh->queueing)
+       ssh2_pkt_queue(ssh, pkt);
+    else
+       ssh2_pkt_send_noqueue(ssh, pkt);
+}
+
+/*
+ * Either queue or defer a packet, depending on whether queueing is
+ * set.
+ */
+static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt)
+{
+    if (ssh->queueing)
+       ssh2_pkt_queue(ssh, pkt);
+    else
+       ssh2_pkt_defer_noqueue(ssh, pkt);
 }
 
 /*
  * Send the whole deferred data block constructed by
  * ssh2_pkt_defer() or SSH1's defer_packet().
+ * 
+ * The expected use of the defer mechanism is that you call
+ * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If
+ * not currently queueing, this simply sets up deferred_send_data
+ * and then sends it. If we _are_ currently queueing, the calls to
+ * ssh2_pkt_defer() put the deferred packets on to the queue
+ * instead, and therefore ssh_pkt_defersend() has no deferred data
+ * to send. Hence, there's no need to make it conditional on
+ * ssh->queueing.
  */
 static void ssh_pkt_defersend(Ssh ssh)
 {
@@ -1597,6 +1720,24 @@ static void ssh_pkt_defersend(Ssh ssh)
        ssh_throttle_all(ssh, 1, backlog);
 }
 
+/*
+ * Send all queued SSH2 packets. We send them by means of
+ * ssh2_pkt_defer_noqueue(), in case they included a pair of
+ * packets that needed to be lumped together.
+ */
+static void ssh2_pkt_queuesend(Ssh ssh)
+{
+    int i;
+
+    assert(!ssh->queueing);
+
+    for (i = 0; i < ssh->queuelen; i++)
+       ssh2_pkt_defer_noqueue(ssh, ssh->queue[i]);
+    ssh->queuelen = 0;
+
+    ssh_pkt_defersend(ssh);
+}
+
 #if 0
 void bndebug(char *string, Bignum b)
 {
@@ -1621,56 +1762,92 @@ static void sha_mpint(SHA_State * s, Bignum b)
 }
 
 /*
- * SSH2 packet decode functions.
+ * Packet decode functions for both SSH1 and SSH2.
  */
-static unsigned long ssh2_pkt_getuint32(Ssh ssh)
+static unsigned long ssh_pkt_getuint32(struct Packet *pkt)
 {
     unsigned long value;
-    if (ssh->pktin.length - ssh->pktin.savedpos < 4)
+    if (pkt->length - pkt->savedpos < 4)
        return 0;                      /* arrgh, no way to decline (FIXME?) */
-    value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
-    ssh->pktin.savedpos += 4;
+    value = GET_32BIT(pkt->body + pkt->savedpos);
+    pkt->savedpos += 4;
     return value;
 }
-static int ssh2_pkt_getbool(Ssh ssh)
+static int ssh2_pkt_getbool(struct Packet *pkt)
 {
     unsigned long value;
-    if (ssh->pktin.length - ssh->pktin.savedpos < 1)
+    if (pkt->length - pkt->savedpos < 1)
        return 0;                      /* arrgh, no way to decline (FIXME?) */
-    value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
-    ssh->pktin.savedpos++;
+    value = pkt->body[pkt->savedpos] != 0;
+    pkt->savedpos++;
     return value;
 }
-static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
+static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length)
 {
     int len;
     *p = NULL;
     *length = 0;
-    if (ssh->pktin.length - ssh->pktin.savedpos < 4)
+    if (pkt->length - pkt->savedpos < 4)
        return;
-    len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
+    len = GET_32BIT(pkt->body + pkt->savedpos);
     if (len < 0)
        return;
     *length = len;
-    ssh->pktin.savedpos += 4;
-    if (ssh->pktin.length - ssh->pktin.savedpos < *length)
+    pkt->savedpos += 4;
+    if (pkt->length - pkt->savedpos < *length)
        return;
-    *p = (char *)(ssh->pktin.data + ssh->pktin.savedpos);
-    ssh->pktin.savedpos += *length;
+    *p = (char *)(pkt->body + pkt->savedpos);
+    pkt->savedpos += *length;
+}
+static void *ssh_pkt_getdata(struct Packet *pkt, int length)
+{
+    if (pkt->length - pkt->savedpos < length)
+       return NULL;
+    pkt->savedpos += length;
+    return pkt->body + (pkt->savedpos - length);
+}
+static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key,
+                             unsigned char **keystr)
+{
+    int j;
+
+    j = makekey(pkt->body + pkt->savedpos,
+               pkt->length - pkt->savedpos,
+               key, keystr, 0);
+
+    if (j < 0)
+       return FALSE;
+    
+    pkt->savedpos += j;
+    assert(pkt->savedpos < pkt->length);
+
+    return TRUE;
+}
+static Bignum ssh1_pkt_getmp(struct Packet *pkt)
+{
+    int j;
+    Bignum b;
+
+    j = ssh1_read_bignum(pkt->body + pkt->savedpos,
+                        pkt->length - pkt->savedpos, &b);
+
+    if (j < 0)
+       return NULL;
+
+    pkt->savedpos += j;
+    return b;
 }
-static Bignum ssh2_pkt_getmp(Ssh ssh)
+static Bignum ssh2_pkt_getmp(struct Packet *pkt)
 {
     char *p;
     int length;
     Bignum b;
 
-    ssh2_pkt_getstring(ssh, &p, &length);
+    ssh_pkt_getstring(pkt, &p, &length);
     if (!p)
        return NULL;
-    if (p[0] & 0x80) {
-       bombout((ssh,"internal error: Can't handle negative mpints"));
+    if (p[0] & 0x80)
        return NULL;
-    }
     b = bignum_from_bytes((unsigned char *)p, length);
     return b;
 }
@@ -1682,7 +1859,8 @@ static Bignum ssh2_pkt_getmp(Ssh ssh)
  * fiddle with the signature packet if necessary for
  * BUG_SSH2_RSA_PADDING.
  */
-static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
+static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt,
+                            void *pkblob_v, int pkblob_len,
                             void *sigblob_v, int sigblob_len)
 {
     unsigned char *pkblob = (unsigned char *)pkblob_v;
@@ -1720,19 +1898,19 @@ static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
 
        if (len != siglen) {
            unsigned char newlen[4];
-           ssh2_pkt_addstring_start(ssh);
-           ssh2_pkt_addstring_data(ssh, (char *)sigblob, pos);
+           ssh2_pkt_addstring_start(pkt);
+           ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos);
            /* dmemdump(sigblob, pos); */
            pos += 4;                  /* point to start of actual sig */
            PUT_32BIT(newlen, len);
-           ssh2_pkt_addstring_data(ssh, (char *)newlen, 4);
+           ssh2_pkt_addstring_data(pkt, (char *)newlen, 4);
            /* dmemdump(newlen, 4); */
            newlen[0] = 0;
            while (len-- > siglen) {
-               ssh2_pkt_addstring_data(ssh, (char *)newlen, 1);
+               ssh2_pkt_addstring_data(pkt, (char *)newlen, 1);
                /* dmemdump(newlen, 1); */
            }
-           ssh2_pkt_addstring_data(ssh, (char *)(sigblob+pos), siglen);
+           ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen);
            /* dmemdump(sigblob+pos, siglen); */
            return;
        }
@@ -1740,8 +1918,8 @@ static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
        /* Otherwise fall through and do it the easy way. */
     }
 
-    ssh2_pkt_addstring_start(ssh);
-    ssh2_pkt_addstring_data(ssh, (char *)sigblob, sigblob_len);
+    ssh2_pkt_addstring_start(pkt);
+    ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len);
 }
 
 /*
@@ -1763,7 +1941,8 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        (ssh->cfg.sshbug_ignore1 == AUTO &&
         (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
          !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
-         !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
+         !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") ||
+         !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) {
        /*
         * These versions don't support SSH1_MSG_IGNORE, so we have
         * to use a different defence against password length
@@ -1775,7 +1954,7 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     if (ssh->cfg.sshbug_plainpw1 == FORCE_ON ||
        (ssh->cfg.sshbug_plainpw1 == AUTO &&
-        (!strcmp(imp, "Cisco-1.25")))) {
+        (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) {
        /*
         * These versions need a plain password sent; they can't
         * handle having a null and a random length of data after
@@ -1799,6 +1978,7 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     if (ssh->cfg.sshbug_hmac2 == FORCE_ON ||
        (ssh->cfg.sshbug_hmac2 == AUTO &&
+        !wc_match("* VShell", imp) &&
         (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
          wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
          wc_match("2.1 *", imp)))) {
@@ -1811,6 +1991,7 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 
     if (ssh->cfg.sshbug_derivekey2 == FORCE_ON ||
        (ssh->cfg.sshbug_derivekey2 == AUTO &&
+        !wc_match("* VShell", imp) &&
         (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) {
        /*
         * These versions have the key-derivation bug (failing to
@@ -1931,12 +2112,12 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
     s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
 
     if (ssh->cfg.sshprot == 0 && !s->proto1) {
-       bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
-       crReturn(0);
+       bombout(("SSH protocol version 1 required by user but not provided by server"));
+       crStop(0);
     }
     if (ssh->cfg.sshprot == 3 && !s->proto2) {
-       bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
-       crReturn(0);
+       bombout(("SSH protocol version 2 required by user but not provided by server"));
+       crStop(0);
     }
 
     if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
@@ -1957,6 +2138,7 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
        logevent("Using SSH protocol version 2");
        sk_write(ssh->s, verstring, strlen(verstring));
        ssh->protocol = ssh2_protocol;
+       ssh2_protocol_setup(ssh);
        ssh->version = 2;
        ssh->s_rdpkt = ssh2_rdpkt;
     } else {
@@ -1974,10 +2156,13 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
        logevent("Using SSH protocol version 1");
        sk_write(ssh->s, verstring, strlen(verstring));
        ssh->protocol = ssh1_protocol;
+       ssh1_protocol_setup(ssh);
        ssh->version = 1;
        ssh->s_rdpkt = ssh1_rdpkt;
     }
+    update_specials_menu(ssh->frontend);
     ssh->state = SSH_STATE_BEFORE_SIZE;
+    ssh->pinger = pinger_new(&ssh->cfg, &ssh_backend, ssh);
 
     sfree(s->vstring);
 
@@ -2015,34 +2200,61 @@ static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
        crReturnV;
     while (1) {
        while (datalen > 0) {
-           if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
-               if (ssh->state == SSH_STATE_CLOSED) {
-                   return;
-               }
-               ssh->protocol(ssh, NULL, 0, 1);
-               if (ssh->state == SSH_STATE_CLOSED) {
-                   return;
-               }
+           struct Packet *pktin = ssh->s_rdpkt(ssh, &data, &datalen);
+           if (pktin) {
+               ssh->protocol(ssh, NULL, 0, pktin);
+               ssh_free_packet(pktin);
            }
+           if (ssh->state == SSH_STATE_CLOSED)
+               return;
        }
        crReturnV;
     }
     crFinishV;
 }
 
-static int ssh_closing(Plug plug, char *error_msg, int error_code,
-                      int calling_back)
+static void ssh_do_close(Ssh ssh)
 {
-    Ssh ssh = (Ssh) plug;
+    int i;
+    struct ssh_channel *c;
+
     ssh->state = SSH_STATE_CLOSED;
     if (ssh->s) {
         sk_close(ssh->s);
         ssh->s = NULL;
+       notify_remote_exit(ssh->frontend);
+    }
+    /*
+     * Now we must shut down any port and X forwardings going
+     * through this connection.
+     */
+    if (ssh->channels) {
+       for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
+           switch (c->type) {
+             case CHAN_X11:
+               x11_close(c->u.x11.s);
+               break;
+             case CHAN_SOCKDATA:
+               pfd_close(c->u.pfd.s);
+               break;
+           }
+           del234(ssh->channels, c);
+           if (ssh->version == 2)
+               bufchain_clear(&c->v.v2.outbuffer);
+           sfree(c);
+       }
     }
+}
+
+static int ssh_closing(Plug plug, const char *error_msg, int error_code,
+                      int calling_back)
+{
+    Ssh ssh = (Ssh) plug;
+    ssh_do_close(ssh);
     if (error_msg) {
        /* A socket error has occurred. */
        logevent(error_msg);
-       connection_fatal(ssh->frontend, error_msg);
+       connection_fatal(ssh->frontend, "%s", error_msg);
     } else {
        /* Otherwise, the remote side closed the connection normally. */
     }
@@ -2054,10 +2266,7 @@ static int ssh_receive(Plug plug, int urgent, char *data, int len)
     Ssh ssh = (Ssh) plug;
     ssh_gotdata(ssh, (unsigned char *)data, len);
     if (ssh->state == SSH_STATE_CLOSED) {
-       if (ssh->s) {
-           sk_close(ssh->s);
-           ssh->s = NULL;
-       }
+       ssh_do_close(ssh);
        return 0;
     }
     return 1;
@@ -2080,8 +2289,8 @@ static void ssh_sent(Plug plug, int bufsize)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static char *connect_to_host(Ssh ssh, char *host, int port,
-                            char **realhost, int nodelay)
+static const char *connect_to_host(Ssh ssh, char *host, int port,
+                                  char **realhost, int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
        ssh_closing,
@@ -2091,7 +2300,7 @@ static char *connect_to_host(Ssh ssh, char *host, int port,
     };
 
     SockAddr addr;
-    char *err;
+    const char *err;
 
     ssh->savedhost = snewn(1 + strlen(host), char);
     if (!ssh->savedhost)
@@ -2107,8 +2316,10 @@ static char *connect_to_host(Ssh ssh, char *host, int port,
      */
     logeventf(ssh, "Looking up host \"%s\"", host);
     addr = name_lookup(host, port, realhost, &ssh->cfg);
-    if ((err = sk_addr_error(addr)) != NULL)
+    if ((err = sk_addr_error(addr)) != NULL) {
+       sk_addr_free(addr);
        return err;
+    }
 
     /*
      * Open socket.
@@ -2120,9 +2331,10 @@ static char *connect_to_host(Ssh ssh, char *host, int port,
     }
     ssh->fn = &fn_table;
     ssh->s = new_connection(addr, *realhost, port,
-                           0, 1, nodelay, (Plug) ssh, &ssh->cfg);
+                           0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg);
     if ((err = sk_socket_error(ssh->s)) != NULL) {
        ssh->s = NULL;
+       notify_remote_exit(ssh->frontend);
        return err;
     }
 
@@ -2173,7 +2385,7 @@ static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
            /* Agent channels require no buffer management. */
            break;
          case CHAN_SOCKDATA:
-           pfd_override_throttle(c->u.x11.s, enable);
+           pfd_override_throttle(c->u.pfd.s, enable);
            break;
        }
     }
@@ -2251,13 +2463,54 @@ static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
     return 0;
 }
 
+static void ssh_agent_callback(void *sshv, void *reply, int replylen)
+{
+    Ssh ssh = (Ssh) sshv;
+
+    ssh->agent_response = reply;
+    ssh->agent_response_len = replylen;
+
+    if (ssh->version == 1)
+       do_ssh1_login(ssh, NULL, -1, NULL);
+    else
+       do_ssh2_authconn(ssh, NULL, -1, NULL);
+}
+
+static void ssh_agentf_callback(void *cv, void *reply, int replylen)
+{
+    struct ssh_channel *c = (struct ssh_channel *)cv;
+    Ssh ssh = c->ssh;
+    void *sentreply = reply;
+
+    if (!sentreply) {
+       /* Fake SSH_AGENT_FAILURE. */
+       sentreply = "\0\0\0\1\5";
+       replylen = 5;
+    }
+    if (ssh->version == 2) {
+       ssh2_add_channel_data(c, sentreply, replylen);
+       ssh2_try_send(c);
+    } else {
+       send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
+                   PKT_INT, c->remoteid,
+                   PKTT_DATA,
+                   PKT_INT, replylen,
+                   PKT_DATA, sentreply, replylen,
+                   PKTT_OTHER,
+                   PKT_END);
+    }
+    if (reply)
+       sfree(reply);
+}
+
 /*
  * Handle the key exchange and user authentication phases.
  */
-static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
+static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
+                        struct Packet *pktin)
 {
-    int i, j;
-    unsigned char cookie[8];
+    int i, j, ret;
+    unsigned char cookie[8], *ptr;
     struct RSAKey servkey, hostkey;
     struct MD5Context md5c;
     struct do_ssh1_login_state {
@@ -2289,20 +2542,30 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
     crBegin(ssh->do_ssh1_login_crstate);
 
-    if (!ispkt)
-       crWaitUntil(ispkt);
+    random_init();
+
+    if (!pktin)
+       crWaitUntil(pktin);
 
-    if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
-       bombout((ssh,"Public key packet not received"));
-       crReturn(0);
+    if (pktin->type != SSH1_SMSG_PUBLIC_KEY) {
+       bombout(("Public key packet not received"));
+       crStop(0);
     }
 
     logevent("Received public keys");
 
-    memcpy(cookie, ssh->pktin.body, 8);
+    ptr = ssh_pkt_getdata(pktin, 8);
+    if (!ptr) {
+       bombout(("SSH1 public key packet stopped before random cookie"));
+       crStop(0);
+    }
+    memcpy(cookie, ptr, 8);
 
-    i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
-    j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
+    if (!ssh1_pkt_getrsakey(pktin, &servkey, &s->keystr1) ||
+       !ssh1_pkt_getrsakey(pktin, &hostkey, &s->keystr2)) {    
+       bombout(("Failed to read SSH1 public keys from public key packet"));
+       crStop(0);
+    }
 
     /*
      * Log the host key fingerprint.
@@ -2317,9 +2580,9 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        logevent(logmsg);
     }
 
-    ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
-    s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
-    s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
+    ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
+    s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
+    s->supported_auths_mask = ssh_pkt_getuint32(pktin);
 
     ssh->v1_local_protoflags =
        ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
@@ -2328,12 +2591,21 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     MD5Init(&md5c);
     MD5Update(&md5c, s->keystr2, hostkey.bytes);
     MD5Update(&md5c, s->keystr1, servkey.bytes);
-    MD5Update(&md5c, ssh->pktin.body, 8);
+    MD5Update(&md5c, cookie, 8);
     MD5Final(s->session_id, &md5c);
 
     for (i = 0; i < 32; i++)
        ssh->session_key[i] = random_byte();
 
+    /*
+     * Verify that the `bits' and `bytes' parameters match.
+     */
+    if (hostkey.bits > hostkey.bytes * 8 ||
+       servkey.bits > servkey.bytes * 8) {
+       bombout(("SSH1 public keys were badly formatted"));
+       crStop(0);
+    }
+
     s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
 
     s->rsabuf = snewn(s->len, unsigned char);
@@ -2367,11 +2639,17 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     }
 
     if (hostkey.bytes > servkey.bytes) {
-       rsaencrypt(s->rsabuf, 32, &servkey);
-       rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
+       ret = rsaencrypt(s->rsabuf, 32, &servkey);
+       if (ret)
+           ret = rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
     } else {
-       rsaencrypt(s->rsabuf, 32, &hostkey);
-       rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
+       ret = rsaencrypt(s->rsabuf, 32, &hostkey);
+       if (ret)
+           ret = rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
+    }
+    if (!ret) {
+       bombout(("SSH1 public key encryptions failed due to bad formatting"));
+       crStop(0);      
     }
 
     logevent("Encrypted session key");
@@ -2403,12 +2681,12 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        }
        if (!cipher_chosen) {
            if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
-               bombout((ssh,"Server violates SSH 1 protocol by not "
+               bombout(("Server violates SSH 1 protocol by not "
                         "supporting 3DES encryption"));
            else
                /* shouldn't happen */
-               bombout((ssh,"No supported ciphers found"));
-           crReturn(0);
+               bombout(("No supported ciphers found"));
+           crStop(0);
        }
 
        /* Warn about chosen cipher if necessary. */
@@ -2449,18 +2727,34 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     ssh->crcda_ctx = crcda_make_context();
     logevent("Installing CRC compensation attack detector");
 
-    crWaitUntil(ispkt);
+    if (servkey.modulus) {
+       sfree(servkey.modulus);
+       servkey.modulus = NULL;
+    }
+    if (servkey.exponent) {
+       sfree(servkey.exponent);
+       servkey.exponent = NULL;
+    }
+    if (hostkey.modulus) {
+       sfree(hostkey.modulus);
+       hostkey.modulus = NULL;
+    }
+    if (hostkey.exponent) {
+       sfree(hostkey.exponent);
+       hostkey.exponent = NULL;
+    }
+    crWaitUntil(pktin);
 
-    if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
-       bombout((ssh,"Encryption not successfully enabled"));
-       crReturn(0);
+    if (pktin->type != SSH1_SMSG_SUCCESS) {
+       bombout(("Encryption not successfully enabled"));
+       crStop(0);
     }
 
     logevent("Successfully started encryption");
 
     fflush(stdout);
     {
-       if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
+       if (!*ssh->cfg.username) {
            if (ssh_get_line && !ssh_getline_pw_only) {
                if (!ssh_get_line("login as: ",
                                  s->username, sizeof(s->username), FALSE)) {
@@ -2469,8 +2763,8 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * Terminate.
                     */
                    logevent("No username provided. Abandoning session.");
-                   ssh->state = SSH_STATE_CLOSED;
-                   crReturn(1);
+                    ssh_closing((Plug)ssh, NULL, 0, 0);
+                   crStop(1);
                }
            } else {
                int ret;               /* need not be kept over crReturn */
@@ -2479,7 +2773,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
                setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
                do {
-                   crWaitUntil(!ispkt);
+                   crWaitUntil(!pktin);
                    ret = process_userpass_input(ssh, in, inlen);
                } while (ret == 0);
                if (ret < 0)
@@ -2504,7 +2798,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        }
     }
 
-    crWaitUntil(ispkt);
+    crWaitUntil(pktin);
 
     if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
        /* We must not attempt PK auth. Pretend we've already tried it. */
@@ -2516,12 +2810,12 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */
     if (!filename_is_null(ssh->cfg.keyfile)) {
        if (!rsakey_pubblob(&ssh->cfg.keyfile,
-                           &s->publickey_blob, &s->publickey_bloblen))
+                           &s->publickey_blob, &s->publickey_bloblen, NULL))
            s->publickey_blob = NULL;
     } else
        s->publickey_blob = NULL;
 
-    while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+    while (pktin->type == SSH1_SMSG_FAILURE) {
        s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
 
        if (agent_exists() && !s->tried_agent) {
@@ -2537,7 +2831,19 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            /* Request the keys held by the agent. */
            PUT_32BIT(s->request, 1);
            s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
-           agent_query(s->request, 5, &r, &s->responselen);
+           if (!agent_query(s->request, 5, &r, &s->responselen,
+                            ssh_agent_callback, ssh)) {
+               do {
+                   crReturn(0);
+                   if (pktin) {
+                       bombout(("Unexpected data from server while waiting"
+                                " for agent response"));
+                       crStop(0);
+                   }
+               } while (pktin || inlen > 0);
+               r = ssh->agent_response;
+               s->responselen = ssh->agent_response_len;
+           }
            s->response = (unsigned char *) r;
            if (s->response && s->responselen >= 5 &&
                s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
@@ -2562,21 +2868,50 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        s->tried_publickey = 1;
                    }
                    s->p += 4;
-                   s->p += ssh1_read_bignum(s->p, &s->key.exponent);
-                   s->p += ssh1_read_bignum(s->p, &s->key.modulus);
-                   s->commentlen = GET_32BIT(s->p);
-                   s->p += 4;
-                   s->commentp = (char *)s->p;
-                   s->p += s->commentlen;
+                   {
+                       int n, ok = FALSE;
+                       do {           /* do while (0) to make breaking easy */
+                           n = ssh1_read_bignum
+                               (s->p, s->responselen-(s->p-s->response),
+                                &s->key.exponent);
+                           if (n < 0)
+                               break;
+                           s->p += n;
+                           n = ssh1_read_bignum
+                               (s->p, s->responselen-(s->p-s->response),
+                                &s->key.modulus);
+                           if (n < 0)
+                           break;
+                           s->p += n;
+                           if (s->responselen - (s->p-s->response) < 4)
+                               break;
+                           s->commentlen = GET_32BIT(s->p);
+                           s->p += 4;
+                           if (s->responselen - (s->p-s->response) <
+                               s->commentlen)
+                               break;
+                           s->commentp = (char *)s->p;
+                           s->p += s->commentlen;
+                           ok = TRUE;
+                       } while (0);
+                       if (!ok) {
+                           logevent("Pageant key list packet was truncated");
+                           break;
+                       }
+                   }
                    send_packet(ssh, SSH1_CMSG_AUTH_RSA,
                                PKT_BIGNUM, s->key.modulus, PKT_END);
-                   crWaitUntil(ispkt);
-                   if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
+                   crWaitUntil(pktin);
+                   if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
                        logevent("Key refused");
                        continue;
                    }
                    logevent("Received RSA challenge");
-                   ssh1_read_bignum(ssh->pktin.body, &s->challenge);
+                   if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) {
+                       bombout(("Server's RSA challenge was badly formatted"));
+                       crStop(0);
+                   }
+
                    {
                        char *agentreq, *q, *ret;
                        void *vret;
@@ -2599,9 +2934,23 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        memcpy(q, s->session_id, 16);
                        q += 16;
                        PUT_32BIT(q, 1);        /* response format */
-                       agent_query(agentreq, len + 4, &vret, &retlen);
+                       if (!agent_query(agentreq, len + 4, &vret, &retlen,
+                                        ssh_agent_callback, ssh)) {
+                           sfree(agentreq);
+                           do {
+                               crReturn(0);
+                               if (pktin) {
+                                   bombout(("Unexpected data from server"
+                                            " while waiting for agent"
+                                            " response"));
+                                   crStop(0);
+                               }
+                           } while (pktin || inlen > 0);
+                           vret = ssh->agent_response;
+                           retlen = ssh->agent_response_len;
+                       } else
+                           sfree(agentreq);
                        ret = vret;
-                       sfree(agentreq);
                        if (ret) {
                            if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
                                logevent("Sending Pageant's response");
@@ -2609,8 +2958,8 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                            PKT_DATA, ret + 5, 16,
                                            PKT_END);
                                sfree(ret);
-                               crWaitUntil(ispkt);
-                               if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
+                               crWaitUntil(pktin);
+                               if (pktin->type == SSH1_SMSG_SUCCESS) {
                                    logevent
                                        ("Pageant's response accepted");
                                    if (flags & FLAG_VERBOSE) {
@@ -2639,6 +2988,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    if (s->authed)
                        break;
                }
+               sfree(s->response);
            }
            if (s->authed)
                break;
@@ -2652,19 +3002,26 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
            logevent("Requested TIS authentication");
            send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
-           crWaitUntil(ispkt);
-           if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
+           crWaitUntil(pktin);
+           if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
                logevent("TIS authentication declined");
                if (flags & FLAG_INTERACTIVE)
                    c_write_str(ssh, "TIS authentication refused.\r\n");
                s->tis_auth_refused = 1;
                continue;
            } else {
-               int challengelen = GET_32BIT(ssh->pktin.body);
+               char *challenge;
+               int challengelen;
+
+               ssh_pkt_getstring(pktin, &challenge, &challengelen);
+               if (!challenge) {
+                   bombout(("TIS challenge packet was badly formed"));
+                   crStop(0);
+               }
                logevent("Received TIS challenge");
                if (challengelen > sizeof(s->prompt) - 1)
                    challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
-               memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
+               memcpy(s->prompt, challenge, challengelen);
                /* Prompt heuristic comes from OpenSSH */
                strncpy(s->prompt + challengelen,
                        memchr(s->prompt, '\n', challengelen) ?
@@ -2679,18 +3036,25 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
            logevent("Requested CryptoCard authentication");
            send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
-           crWaitUntil(ispkt);
-           if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
+           crWaitUntil(pktin);
+           if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
                logevent("CryptoCard authentication declined");
                c_write_str(ssh, "CryptoCard authentication refused.\r\n");
                s->ccard_auth_refused = 1;
                continue;
            } else {
-               int challengelen = GET_32BIT(ssh->pktin.body);
+               char *challenge;
+               int challengelen;
+
+               ssh_pkt_getstring(pktin, &challenge, &challengelen);
+               if (!challenge) {
+                   bombout(("CryptoCard challenge packet was badly formed"));
+                   crStop(0);
+               }
                logevent("Received CryptoCard challenge");
                if (challengelen > sizeof(s->prompt) - 1)
                    challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
-               memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
+               memcpy(s->prompt, challenge, challengelen);
                strncpy(s->prompt + challengelen,
                        memchr(s->prompt, '\n', challengelen) ?
                        "" : "\r\nResponse: ",
@@ -2747,8 +3111,8 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                            PKT_END);
                logevent("Unable to authenticate");
                connection_fatal(ssh->frontend, "Unable to authenticate");
-               ssh->state = SSH_STATE_CLOSED;
-               crReturn(1);
+                ssh_closing((Plug)ssh, NULL, 0, 0);
+               crStop(1);
            }
        } else {
            /* Prompt may have come from server. We've munged it a bit, so
@@ -2759,7 +3123,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
            setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
            do {
-               crWaitUntil(!ispkt);
+               crWaitUntil(!pktin);
                ret = process_userpass_input(ssh, in, inlen);
            } while (ret == 0);
            if (ret < 0)
@@ -2776,11 +3140,15 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            s->tried_publickey = 1;
            
            {
-               int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password);
+               const char *error = NULL;
+               int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password,
+                                    &error);
                if (ret == 0) {
                    c_write_str(ssh, "Couldn't load private key from ");
                    c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile));
-                   c_write_str(ssh, ".\r\n");
+                   c_write_str(ssh, " (");
+                   c_write_str(ssh, error);
+                   c_write_str(ssh, ").\r\n");
                    continue;          /* go and try password */
                }
                if (ret == -1) {
@@ -2796,14 +3164,14 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            send_packet(ssh, SSH1_CMSG_AUTH_RSA,
                        PKT_BIGNUM, s->key.modulus, PKT_END);
 
-           crWaitUntil(ispkt);
-           if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+           crWaitUntil(pktin);
+           if (pktin->type == SSH1_SMSG_FAILURE) {
                c_write_str(ssh, "Server refused our public key.\r\n");
                continue;              /* go and try password */
            }
-           if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
-               bombout((ssh,"Bizarre response to offer of public key"));
-               crReturn(0);
+           if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
+               bombout(("Bizarre response to offer of public key"));
+               crStop(0);
            }
 
            {
@@ -2811,7 +3179,10 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                unsigned char buffer[32];
                Bignum challenge, response;
 
-               ssh1_read_bignum(ssh->pktin.body, &challenge);
+               if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) {
+                   bombout(("Server's RSA challenge was badly formatted"));
+                   crStop(0);
+               }
                response = rsadecrypt(challenge, &s->key);
                freebn(s->key.private_exponent);/* burn the evidence */
 
@@ -2831,15 +3202,15 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                freebn(response);
            }
 
-           crWaitUntil(ispkt);
-           if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+           crWaitUntil(pktin);
+           if (pktin->type == SSH1_SMSG_FAILURE) {
                if (flags & FLAG_VERBOSE)
                    c_write_str(ssh, "Failed to authenticate with"
                                " our public key.\r\n");
                continue;              /* go and try password */
-           } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
-               bombout((ssh,"Bizarre response to RSA authentication response"));
-               crReturn(0);
+           } else if (pktin->type != SSH1_SMSG_SUCCESS) {
+               bombout(("Bizarre response to RSA authentication response"));
+               crStop(0);
            }
 
            break;                     /* we're through! */
@@ -2905,10 +3276,11 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    randomstr = snewn(top + 1, char);
 
                    for (i = bottom; i <= top; i++) {
-                       if (i == pwlen)
+                       if (i == pwlen) {
                            defer_packet(ssh, s->pwpkt_type,
-                                        PKT_STR, s->password, PKT_END);
-                       else {
+                                        PKTT_PASSWORD, PKT_STR, s->password,
+                                        PKTT_OTHER, PKT_END);
+                       } else {
                            for (j = 0; j < i; j++) {
                                do {
                                    randomstr[j] = random_byte();
@@ -2921,6 +3293,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    }
                    logevent("Sending password with camouflage packets");
                    ssh_pkt_defersend(ssh);
+                   sfree(randomstr);
                } 
                else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
                    /*
@@ -2944,8 +3317,9 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        ss = s->password;
                    }
                    logevent("Sending length-padded password");
-                   send_packet(ssh, s->pwpkt_type, PKT_INT, len,
-                               PKT_DATA, ss, len, PKT_END);
+                   send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
+                               PKT_INT, len, PKT_DATA, ss, len,
+                               PKTT_OTHER, PKT_END);
                } else {
                    /*
                     * The server has _both_
@@ -2956,23 +3330,26 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    int len;
                    len = strlen(s->password);
                    logevent("Sending unpadded password");
-                   send_packet(ssh, s->pwpkt_type, PKT_INT, len,
-                               PKT_DATA, s->password, len, PKT_END);
+                   send_packet(ssh, s->pwpkt_type,
+                               PKTT_PASSWORD, PKT_INT, len,
+                               PKT_DATA, s->password, len,
+                               PKTT_OTHER, PKT_END);
                }
            } else {
-               send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
+               send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD,
+                           PKT_STR, s->password, PKTT_OTHER, PKT_END);
            }
        }
        logevent("Sent password");
        memset(s->password, 0, strlen(s->password));
-       crWaitUntil(ispkt);
-       if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+       crWaitUntil(pktin);
+       if (pktin->type == SSH1_SMSG_FAILURE) {
            if (flags & FLAG_VERBOSE)
                c_write_str(ssh, "Access denied\r\n");
            logevent("Authentication refused");
-       } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
-           bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
-           crReturn(0);
+       } else if (pktin->type != SSH1_SMSG_SUCCESS) {
+           bombout(("Strange packet received, type %d", pktin->type));
+           crStop(0);
        }
     }
 
@@ -2985,6 +3362,11 @@ void sshfwd_close(struct ssh_channel *c)
 {
     Ssh ssh = c->ssh;
 
+    if (ssh->state != SSH_STATE_SESSION) {
+       assert(ssh->state == SSH_STATE_CLOSED);
+       return;
+    }
+
     if (c && !c->closes) {
        /*
         * If the channel's remoteid is -1, we have sent
@@ -2998,9 +3380,10 @@ void sshfwd_close(struct ssh_channel *c)
                send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
                            PKT_END);
            } else {
-               ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
-               ssh2_pkt_adduint32(ssh, c->remoteid);
-               ssh2_pkt_send(ssh);
+               struct Packet *pktout;
+               pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
+               ssh2_pkt_adduint32(pktout, c->remoteid);
+               ssh2_pkt_send(ssh, pktout);
            }
        }
        c->closes = 1;                 /* sent MSG_CLOSE */
@@ -3019,10 +3402,17 @@ int sshfwd_write(struct ssh_channel *c, char *buf, int len)
 {
     Ssh ssh = c->ssh;
 
+    if (ssh->state != SSH_STATE_SESSION) {
+       assert(ssh->state == SSH_STATE_CLOSED);
+       return 0;
+    }
+
     if (ssh->version == 1) {
        send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
                    PKT_INT, c->remoteid,
-                   PKT_INT, len, PKT_DATA, buf, len, PKT_END);
+                   PKTT_DATA,
+                   PKT_INT, len, PKT_DATA, buf, len,
+                   PKTT_OTHER, PKT_END);
        /*
         * In SSH1 we can return 0 here - implying that forwarded
         * connections are never individually throttled - because
@@ -3041,6 +3431,11 @@ void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
 {
     Ssh ssh = c->ssh;
 
+    if (ssh->state != SSH_STATE_SESSION) {
+       assert(ssh->state == SSH_STATE_CLOSED);
+       return;
+    }
+
     if (ssh->version == 1) {
        if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
            c->v.v1.throttling = 0;
@@ -3051,29 +3446,22 @@ void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
     }
 }
 
-static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
+static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
+                              struct Packet *pktin)
 {
-    crBegin(ssh->ssh1_protocol_crstate);
-
-    random_init();
-
-    while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
-       crReturnV;
-    }
-    if (ssh->state == SSH_STATE_CLOSED)
-       crReturnV;
+    crBegin(ssh->do_ssh1_connection_crstate);
 
     if (ssh->cfg.agentfwd && agent_exists()) {
        logevent("Requesting agent forwarding");
        send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
        do {
            crReturnV;
-       } while (!ispkt);
-       if (ssh->pktin.type != SSH1_SMSG_SUCCESS
-           && ssh->pktin.type != SSH1_SMSG_FAILURE) {
-           bombout((ssh,"Protocol confusion"));
-           crReturnV;
-       } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+       } while (!pktin);
+       if (pktin->type != SSH1_SMSG_SUCCESS
+           && pktin->type != SSH1_SMSG_FAILURE) {
+           bombout(("Protocol confusion"));
+           crStopV;
+       } else if (pktin->type == SSH1_SMSG_FAILURE) {
            logevent("Agent forwarding refused");
        } else {
            logevent("Agent forwarding enabled");
@@ -3098,12 +3486,12 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        }
        do {
            crReturnV;
-       } while (!ispkt);
-       if (ssh->pktin.type != SSH1_SMSG_SUCCESS
-           && ssh->pktin.type != SSH1_SMSG_FAILURE) {
-           bombout((ssh,"Protocol confusion"));
-           crReturnV;
-       } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+       } while (!pktin);
+       if (pktin->type != SSH1_SMSG_SUCCESS
+           && pktin->type != SSH1_SMSG_FAILURE) {
+           bombout(("Protocol confusion"));
+           crStopV;
+       } else if (pktin->type == SSH1_SMSG_FAILURE) {
            logevent("X11 forwarding refused");
        } else {
            logevent("X11 forwarding enabled");
@@ -3142,30 +3530,36 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
            }
            sports[n] = 0;
-           if (*ssh->portfwd_strptr == '\t')
-               ssh->portfwd_strptr++;
-           n = 0;
-           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
-               if (n < 255) host[n++] = *ssh->portfwd_strptr++;
-           }
-           host[n] = 0;
-           if (*ssh->portfwd_strptr == ':')
+           if (type != 'D') {
+               if (*ssh->portfwd_strptr == '\t')
+                   ssh->portfwd_strptr++;
+               n = 0;
+               while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
+                   if (n < 255) host[n++] = *ssh->portfwd_strptr++;
+               }
+               host[n] = 0;
+               if (*ssh->portfwd_strptr == ':')
+                   ssh->portfwd_strptr++;
+               n = 0;
+               while (*ssh->portfwd_strptr) {
+                   if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
+               }
+               dports[n] = 0;
                ssh->portfwd_strptr++;
-           n = 0;
-           while (*ssh->portfwd_strptr) {
-               if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
-           }
-           dports[n] = 0;
-           ssh->portfwd_strptr++;
-           dport = atoi(dports);
-           dserv = 0;
-           if (dport == 0) {
-               dserv = 1;
-               dport = net_service_lookup(dports);
-               if (!dport) {
-                   logeventf(ssh, "Service lookup failed for"
-                             " destination port \"%s\"", dports);
+               dport = atoi(dports);
+               dserv = 0;
+               if (dport == 0) {
+                   dserv = 1;
+                   dport = net_service_lookup(dports);
+                   if (!dport) {
+                       logeventf(ssh, "Service lookup failed for"
+                                 " destination port \"%s\"", dports);
+                   }
                }
+           } else {
+               while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
+               dport = dserv = -1;
+               ssh->portfwd_strptr++; /* eat the NUL and move to next one */
            }
            sport = atoi(sports);
            sserv = 0;
@@ -3178,24 +3572,47 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                }
            }
            if (sport && dport) {
+               /* Set up a description of the source port. */
+               static char *sportdesc;
+               sportdesc = dupprintf("%.*s%.*s%.*s%.*s%d%.*s",
+                       (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
+                       (int)(*saddr?1:0), ":",
+                       (int)(sserv ? strlen(sports) : 0), sports,
+                       sserv, "(", sport, sserv, ")");
                if (type == 'L') {
-                   pfd_addforward(host, dport, *saddr ? saddr : NULL,
-                                  sport, ssh, &ssh->cfg);
-                   logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
-                             " forwarding to %s:%.*s%.*s%d%.*s",
-                             (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
-                             (int)(*saddr?1:0), ":",
-                             (int)(sserv ? strlen(sports) : 0), sports,
-                             sserv, "(", sport, sserv, ")",
-                             host,
-                             (int)(dserv ? strlen(dports) : 0), dports,
-                             dserv, "(", dport, dserv, ")");
+                   /* Verbose description of the destination port */
+                   char *dportdesc = dupprintf("%s:%.*s%.*s%d%.*s",
+                           host,
+                           (int)(dserv ? strlen(dports) : 0), dports,
+                           dserv, "(", dport, dserv, ")");
+                   const char *err = pfd_addforward(host, dport,
+                                                    *saddr ? saddr : NULL,
+                                                    sport, ssh, &ssh->cfg);
+                   if (err) {
+                       logeventf(ssh, "Local port %s forward to %s"
+                                 " failed: %s", sportdesc, dportdesc, err);
+                   } else {
+                       logeventf(ssh, "Local port %s forwarding to %s",
+                                 sportdesc, dportdesc);
+                   }
+                   sfree(dportdesc);
+               } else if (type == 'D') {
+                   const char *err = pfd_addforward(NULL, -1,
+                                                    *saddr ? saddr : NULL,
+                                                    sport, ssh, &ssh->cfg);
+                   if (err) {
+                       logeventf(ssh, "Local port %s SOCKS dynamic forward"
+                                 " setup failed: %s", sportdesc, err);
+                   } else {
+                       logeventf(ssh, "Local port %s doing SOCKS"
+                                 " dynamic forwarding", sportdesc);
+                   }
                } else {
                    struct ssh_rportfwd *pf;
                    pf = snew(struct ssh_rportfwd);
                    strcpy(pf->dhost, host);
                    pf->dport = dport;
-                   if (saddr) {
+                   if (*saddr) {
                        logeventf(ssh,
                                  "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
                                  saddr, sport);
@@ -3220,41 +3637,51 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                    PKT_END);
                        do {
                            crReturnV;
-                       } while (!ispkt);
-                       if (ssh->pktin.type != SSH1_SMSG_SUCCESS
-                           && ssh->pktin.type != SSH1_SMSG_FAILURE) {
-                           bombout((ssh,"Protocol confusion"));
-                           crReturnV;
-                       } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+                       } while (!pktin);
+                       if (pktin->type != SSH1_SMSG_SUCCESS
+                           && pktin->type != SSH1_SMSG_FAILURE) {
+                           bombout(("Protocol confusion"));
+                           crStopV;
+                       } else if (pktin->type == SSH1_SMSG_FAILURE) {
                            c_write_str(ssh, "Server refused port"
                                        " forwarding\r\n");
                        }
                        logevent("Remote port forwarding enabled");
                    }
                }
+               sfree(sportdesc);
            }
        }
     }
 
     if (!ssh->cfg.nopty) {
+       /* Unpick the terminal-speed string. */
+       /* XXX perhaps we should allow no speeds to be sent. */
+       ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
+       sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
+       /* Send the pty request. */
        send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
                    PKT_STR, ssh->cfg.termtype,
                    PKT_INT, ssh->term_height,
                    PKT_INT, ssh->term_width,
-                   PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
+                   PKT_INT, 0, PKT_INT, 0, /* width,height in pixels */
+                   PKT_CHAR, 192, PKT_INT, ssh->ispeed, /* TTY_OP_ISPEED */
+                   PKT_CHAR, 193, PKT_INT, ssh->ospeed, /* TTY_OP_OSPEED */
+                   PKT_CHAR, 0, PKT_END);
        ssh->state = SSH_STATE_INTERMED;
        do {
            crReturnV;
-       } while (!ispkt);
-       if (ssh->pktin.type != SSH1_SMSG_SUCCESS
-           && ssh->pktin.type != SSH1_SMSG_FAILURE) {
-           bombout((ssh,"Protocol confusion"));
-           crReturnV;
-       } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+       } while (!pktin);
+       if (pktin->type != SSH1_SMSG_SUCCESS
+           && pktin->type != SSH1_SMSG_FAILURE) {
+           bombout(("Protocol confusion"));
+           crStopV;
+       } else if (pktin->type == SSH1_SMSG_FAILURE) {
            c_write_str(ssh, "Server refused to allocate pty\r\n");
            ssh->editing = ssh->echoing = 1;
        }
-       logevent("Allocated pty");
+       logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
+                 ssh->ospeed, ssh->ispeed);
     } else {
        ssh->editing = ssh->echoing = 1;
     }
@@ -3263,12 +3690,12 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
        do {
            crReturnV;
-       } while (!ispkt);
-       if (ssh->pktin.type != SSH1_SMSG_SUCCESS
-           && ssh->pktin.type != SSH1_SMSG_FAILURE) {
-           bombout((ssh,"Protocol confusion"));
-           crReturnV;
-       } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+       } while (!pktin);
+       if (pktin->type != SSH1_SMSG_SUCCESS
+           && pktin->type != SSH1_SMSG_FAILURE) {
+           bombout(("Protocol confusion"));
+           crStopV;
+       } else if (pktin->type == SSH1_SMSG_FAILURE) {
            c_write_str(ssh, "Server refused to compress\r\n");
        }
        logevent("Started compression");
@@ -3312,32 +3739,41 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     ssh->channels = newtree234(ssh_channelcmp);
     while (1) {
        crReturnV;
-       if (ispkt) {
-           if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
-               ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
-               long len = GET_32BIT(ssh->pktin.body);
-               int bufsize =
+       if (pktin) {
+           if (pktin->type == SSH1_SMSG_STDOUT_DATA ||
+               pktin->type == SSH1_SMSG_STDERR_DATA) {
+               char *string;
+               int stringlen, bufsize;
+
+               ssh_pkt_getstring(pktin, &string, &stringlen);
+               if (string == NULL) {
+                   bombout(("Incoming terminal data packet was badly formed"));
+                   crStopV;
+               }
+
+               bufsize =
                    from_backend(ssh->frontend,
-                                ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
-                                (char *)(ssh->pktin.body) + 4, len);
+                                pktin->type == SSH1_SMSG_STDERR_DATA,
+                                string, stringlen);
                if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
                    ssh->v1_stdout_throttling = 1;
                    ssh1_throttle(ssh, +1);
                }
-           } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
-               ssh->state = SSH_STATE_CLOSED;
+           } else if (pktin->type == SSH1_MSG_DISCONNECT) {
+                ssh_closing((Plug)ssh, NULL, 0, 0);
                logevent("Received disconnect request");
-               crReturnV;
-           } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
+               crStopV;
+           } else if (pktin->type == SSH1_SMSG_X11_OPEN) {
                /* Remote side is trying to open a channel to talk to our
                 * X-Server. Give them back a local channel number. */
                struct ssh_channel *c;
+               int remoteid = ssh_pkt_getuint32(pktin);
 
                logevent("Received X11 connect request");
                /* Refuse if X11 forwarding is disabled. */
                if (!ssh->X11_fwd_enabled) {
                    send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
-                               PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
+                               PKT_INT, remoteid, PKT_END);
                    logevent("Rejected X11 connect request");
                } else {
                    c = snew(struct ssh_channel);
@@ -3345,15 +3781,14 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
                    if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
                                 ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
-                       logevent("opening X11 forward connection failed");
+                       logevent("Opening X11 forward connection failed");
                        sfree(c);
                        send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
-                                   PKT_INT, GET_32BIT(ssh->pktin.body),
-                                   PKT_END);
+                                   PKT_INT, remoteid, PKT_END);
                    } else {
                        logevent
-                           ("opening X11 forward connection succeeded");
-                       c->remoteid = GET_32BIT(ssh->pktin.body);
+                           ("Opening X11 forward connection succeeded");
+                       c->remoteid = remoteid;
                        c->localid = alloc_channel_id(ssh);
                        c->closes = 0;
                        c->v.v1.throttling = 0;
@@ -3365,19 +3800,20 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        logevent("Opened X11 forward channel");
                    }
                }
-           } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
+           } else if (pktin->type == SSH1_SMSG_AGENT_OPEN) {
                /* Remote side is trying to open a channel to talk to our
                 * agent. Give them back a local channel number. */
                struct ssh_channel *c;
+               int remoteid = ssh_pkt_getuint32(pktin);
 
                /* Refuse if agent forwarding is disabled. */
                if (!ssh->agentfwd_enabled) {
                    send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
-                               PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
+                               PKT_INT, remoteid, PKT_END);
                } else {
                    c = snew(struct ssh_channel);
                    c->ssh = ssh;
-                   c->remoteid = GET_32BIT(ssh->pktin.body);
+                   c->remoteid = remoteid;
                    c->localid = alloc_channel_id(ssh);
                    c->closes = 0;
                    c->v.v1.throttling = 0;
@@ -3388,51 +3824,49 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                PKT_INT, c->remoteid, PKT_INT, c->localid,
                                PKT_END);
                }
-           } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
+           } else if (pktin->type == SSH1_MSG_PORT_OPEN) {
                /* Remote side is trying to open a channel to talk to a
                 * forwarded port. Give them back a local channel number. */
                struct ssh_channel *c;
                struct ssh_rportfwd pf;
+               int remoteid;
                int hostsize, port;
-               char host[256], buf[1024];
-               char *p, *h, *e;
+               char *host, buf[1024];
+               const char *e;
                c = snew(struct ssh_channel);
                c->ssh = ssh;
 
-               hostsize = GET_32BIT(ssh->pktin.body+4);
-               for (h = host, p = (char *)(ssh->pktin.body+8);
-                    hostsize != 0; hostsize--) {
-                   if (h+1 < host+sizeof(host))
-                       *h++ = *p;
-                   p++;
-               }
-               *h = 0;
-               port = GET_32BIT(p);
+               remoteid = ssh_pkt_getuint32(pktin);
+               ssh_pkt_getstring(pktin, &host, &hostsize);
+               port = ssh_pkt_getuint32(pktin);
 
-               strcpy(pf.dhost, host);
+               if (hostsize >= lenof(pf.dhost))
+                   hostsize = lenof(pf.dhost)-1;
+               memcpy(pf.dhost, host, hostsize);
+               pf.dhost[hostsize] = '\0';
                pf.dport = port;
 
                if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
                    sprintf(buf, "Rejected remote port open request for %s:%d",
-                           host, port);
+                           pf.dhost, port);
                    logevent(buf);
                     send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
-                                PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
+                                PKT_INT, remoteid, PKT_END);
                } else {
                    sprintf(buf, "Received remote port open request for %s:%d",
-                           host, port);
+                           pf.dhost, port);
                    logevent(buf);
-                   e = pfd_newconnect(&c->u.pfd.s, host, port, c, &ssh->cfg);
+                   e = pfd_newconnect(&c->u.pfd.s, pf.dhost, port,
+                                      c, &ssh->cfg);
                    if (e != NULL) {
                        char buf[256];
                        sprintf(buf, "Port open failed: %s", e);
                        logevent(buf);
                        sfree(c);
                        send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
-                                   PKT_INT, GET_32BIT(ssh->pktin.body),
-                                   PKT_END);
+                                   PKT_INT, remoteid, PKT_END);
                    } else {
-                       c->remoteid = GET_32BIT(ssh->pktin.body);
+                       c->remoteid = remoteid;
                        c->localid = alloc_channel_id(ssh);
                        c->closes = 0;
                        c->v.v1.throttling = 0;
@@ -3445,9 +3879,9 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    }
                }
 
-           } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
-               unsigned int remoteid = GET_32BIT(ssh->pktin.body);
-               unsigned int localid = GET_32BIT(ssh->pktin.body+4);
+           } else if (pktin->type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
+               unsigned int remoteid = ssh_pkt_getuint32(pktin);
+               unsigned int localid = ssh_pkt_getuint32(pktin);
                struct ssh_channel *c;
 
                c = find234(ssh->channels, &remoteid, ssh_channelfind);
@@ -3469,8 +3903,8 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                PKT_INT, c->remoteid, PKT_END);
                }
 
-           } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
-               unsigned int remoteid = GET_32BIT(ssh->pktin.body);
+           } else if (pktin->type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
+               unsigned int remoteid = ssh_pkt_getuint32(pktin);
                struct ssh_channel *c;
 
                c = find234(ssh->channels, &remoteid, ssh_channelfind);
@@ -3481,16 +3915,16 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    sfree(c);
                }
 
-           } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
-                      ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
+           } else if (pktin->type == SSH1_MSG_CHANNEL_CLOSE ||
+                      pktin->type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
                /* Remote side closes a channel. */
-               unsigned i = GET_32BIT(ssh->pktin.body);
+               unsigned i = ssh_pkt_getuint32(pktin);
                struct ssh_channel *c;
                c = find234(ssh->channels, &i, ssh_channelfind);
                if (c && ((int)c->remoteid) != -1) {
                    int closetype;
                    closetype =
-                       (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
+                       (pktin->type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
 
                    if ((c->closes == 0) && (c->type == CHAN_X11)) {
                        logevent("Forwarded X11 connection terminated");
@@ -3507,7 +3941,7 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
                    c->closes |= (closetype << 2);   /* seen this message */
                    if (!(c->closes & closetype)) {
-                       send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
+                       send_packet(ssh, pktin->type, PKT_INT, c->remoteid,
                                    PKT_END);
                        c->closes |= closetype;      /* sent it too */
                    }
@@ -3517,26 +3951,30 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        sfree(c);
                    }
                } else {
-                   bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
-                            ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
+                   bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
+                            pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" :
                             "_CONFIRMATION", c ? "half-open" : "nonexistent",
                             i));
+                   crStopV;
                }
-           } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
+           } else if (pktin->type == SSH1_MSG_CHANNEL_DATA) {
                /* Data sent down one of our channels. */
-               int i = GET_32BIT(ssh->pktin.body);
-               int len = GET_32BIT(ssh->pktin.body + 4);
-               unsigned char *p = ssh->pktin.body + 8;
+               int i = ssh_pkt_getuint32(pktin);
+               char *p;
+               int len;
                struct ssh_channel *c;
+
+               ssh_pkt_getstring(pktin, &p, &len);
+
                c = find234(ssh->channels, &i, ssh_channelfind);
                if (c) {
-                   int bufsize;
+                   int bufsize = 0;
                    switch (c->type) {
                      case CHAN_X11:
-                       bufsize = x11_send(c->u.x11.s, (char *)p, len);
+                       bufsize = x11_send(c->u.x11.s, p, len);
                        break;
                      case CHAN_SOCKDATA:
-                       bufsize = pfd_send(c->u.pfd.s, (char *)p, len);
+                       bufsize = pfd_send(c->u.pfd.s, p, len);
                        break;
                      case CHAN_AGENT:
                        /* Data for an agent message. Buffer it. */
@@ -3567,25 +4005,13 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                c->u.a.lensofar += l;
                            }
                            if (c->u.a.lensofar == c->u.a.totallen) {
-                               void *reply, *sentreply;
+                               void *reply;
                                int replylen;
-                               agent_query(c->u.a.message,
-                                           c->u.a.totallen, &reply,
-                                           &replylen);
-                               if (reply)
-                                   sentreply = reply;
-                               else {
-                                   /* Fake SSH_AGENT_FAILURE. */
-                                   sentreply = "\0\0\0\1\5";
-                                   replylen = 5;
-                               }
-                               send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
-                                           PKT_INT, c->remoteid,
-                                           PKT_INT, replylen,
-                                           PKT_DATA, sentreply, replylen,
-                                           PKT_END);
-                               if (reply)
-                                   sfree(reply);
+                               if (agent_query(c->u.a.message,
+                                               c->u.a.totallen,
+                                               &reply, &replylen,
+                                               ssh_agentf_callback, c))
+                                   ssh_agentf_callback(c, reply, replylen);
                                sfree(c->u.a.message);
                                c->u.a.lensofar = 0;
                            }
@@ -3598,14 +4024,14 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        ssh1_throttle(ssh, +1);
                    }
                }
-           } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
+           } else if (pktin->type == SSH1_SMSG_SUCCESS) {
                /* may be from EXEC_SHELL on some servers */
-           } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+           } else if (pktin->type == SSH1_SMSG_FAILURE) {
                /* may be from EXEC_SHELL on some servers
                 * if no pty is available or in other odd cases. Ignore */
-           } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
+           } else if (pktin->type == SSH1_SMSG_EXIT_STATUS) {
                char buf[100];
-               ssh->exitcode = GET_32BIT(ssh->pktin.body);
+               ssh->exitcode = ssh_pkt_getuint32(pktin);
                sprintf(buf, "Server sent command exit status %d",
                        ssh->exitcode);
                logevent(buf);
@@ -3617,17 +4043,18 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                  * encrypted packet, we close the session once
                  * we've sent EXIT_CONFIRMATION.
                  */
-                ssh->state = SSH_STATE_CLOSED;
-                crReturnV;
+                ssh_closing((Plug)ssh, NULL, 0, 0);
+                crStopV;
            } else {
-               bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
-               crReturnV;
+               bombout(("Strange packet received: type %d", pktin->type));
+               crStopV;
            }
        } else {
            while (inlen > 0) {
                int len = min(inlen, 512);
-               send_packet(ssh, SSH1_CMSG_STDIN_DATA,
-                           PKT_INT, len, PKT_DATA, in, len, PKT_END);
+               send_packet(ssh, SSH1_CMSG_STDIN_DATA, PKTT_DATA,
+                           PKT_INT, len, PKT_DATA, in, len,
+                           PKTT_OTHER, PKT_END);
                in += len;
                inlen -= len;
            }
@@ -3638,15 +4065,83 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 }
 
 /*
- * Utility routine for decoding comma-separated strings in KEXINIT.
+ * Handle the top-level SSH2 protocol.
  */
-static int in_commasep_string(char *needle, char *haystack, int haylen)
+static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
 {
-    int needlen;
-    if (!needle || !haystack)         /* protect against null pointers */
-       return 0;
-    needlen = strlen(needle);
-    while (1) {
+    char *buf, *msg;
+    int msglen;
+
+    ssh_pkt_getstring(pktin, &msg, &msglen);
+    buf = dupprintf("Remote debug message: %.*s", msglen, msg);
+    logevent(buf);
+    sfree(buf);
+}
+
+static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
+{
+    /* log reason code in disconnect message */
+    char *msg;
+    int msglen;
+
+    ssh_pkt_getstring(pktin, &msg, &msglen);
+    bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
+}
+
+void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
+{
+    /* Do nothing, because we're ignoring it! Duhh. */
+}
+
+static void ssh1_protocol_setup(Ssh ssh)
+{
+    int i;
+
+    /*
+     * Most messages are handled by the coroutines.
+     */
+    for (i = 0; i < 256; i++)
+       ssh->packet_dispatch[i] = NULL;
+
+    /*
+     * These special message types we install handlers for.
+     */
+    ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
+    ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
+    ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
+}
+
+static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen,
+                         struct Packet *pktin)
+{
+    if (ssh->state == SSH_STATE_CLOSED)
+       return;
+
+    if (pktin && ssh->packet_dispatch[pktin->type]) {
+       ssh->packet_dispatch[pktin->type](ssh, pktin);
+       return;
+    }
+
+    if (!ssh->protocol_initial_phase_done) {
+       if (do_ssh1_login(ssh, in, inlen, pktin))
+           ssh->protocol_initial_phase_done = TRUE;
+       else
+           return;
+    }
+
+    do_ssh1_connection(ssh, in, inlen, pktin);
+}
+
+/*
+ * Utility routine for decoding comma-separated strings in KEXINIT.
+ */
+static int in_commasep_string(char *needle, char *haystack, int haylen)
+{
+    int needlen;
+    if (!needle || !haystack)         /* protect against null pointers */
+       return 0;
+    needlen = strlen(needle);
+    while (1) {
        /*
         * Is it at the start of the string?
         */
@@ -3696,7 +4191,8 @@ static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
 /*
  * Handle the SSH2 transport layer.
  */
-static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
+static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen,
+                            struct Packet *pktin)
 {
     struct do_ssh2_transport_state {
        int nbits, pbits, warn;
@@ -3718,6 +4214,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
        const struct ssh_compress *preferred_comp;
        int first_kex;
+       struct Packet *pktout;
     };
     crState(do_ssh2_transport_state);
 
@@ -3784,105 +4281,115 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        int i, j, cipherstr_started;
 
        /*
+        * Enable queueing of outgoing auth- or connection-layer
+        * packets while we are in the middle of a key exchange.
+        */
+       ssh->queueing = TRUE;
+
+       /*
         * Construct and send our key exchange packet.
         */
-       ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
+       s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
        for (i = 0; i < 16; i++)
-           ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
+           ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
        /* List key exchange algorithms. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        for (i = 0; i < lenof(kex_algs); i++) {
            if (kex_algs[i] == &ssh_diffiehellman_gex &&
                (ssh->remote_bugs & BUG_SSH2_DH_GEX))
                continue;
-           ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
+           ssh2_pkt_addstring_str(s->pktout, kex_algs[i]->name);
            if (i < lenof(kex_algs) - 1)
-               ssh2_pkt_addstring_str(ssh, ",");
+               ssh2_pkt_addstring_str(s->pktout, ",");
        }
        /* List server host key algorithms. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        for (i = 0; i < lenof(hostkey_algs); i++) {
-           ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
+           ssh2_pkt_addstring_str(s->pktout, hostkey_algs[i]->name);
            if (i < lenof(hostkey_algs) - 1)
-               ssh2_pkt_addstring_str(ssh, ",");
+               ssh2_pkt_addstring_str(s->pktout, ",");
        }
        /* List client->server encryption algorithms. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        cipherstr_started = 0;
        for (i = 0; i < s->n_preferred_ciphers; i++) {
            const struct ssh2_ciphers *c = s->preferred_ciphers[i];
            if (!c) continue;          /* warning flag */
            for (j = 0; j < c->nciphers; j++) {
                if (cipherstr_started)
-                   ssh2_pkt_addstring_str(ssh, ",");
-               ssh2_pkt_addstring_str(ssh, c->list[j]->name);
+                   ssh2_pkt_addstring_str(s->pktout, ",");
+               ssh2_pkt_addstring_str(s->pktout, c->list[j]->name);
                cipherstr_started = 1;
            }
        }
        /* List server->client encryption algorithms. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        cipherstr_started = 0;
        for (i = 0; i < s->n_preferred_ciphers; i++) {
            const struct ssh2_ciphers *c = s->preferred_ciphers[i];
            if (!c) continue; /* warning flag */
            for (j = 0; j < c->nciphers; j++) {
                if (cipherstr_started)
-                   ssh2_pkt_addstring_str(ssh, ",");
-               ssh2_pkt_addstring_str(ssh, c->list[j]->name);
+                   ssh2_pkt_addstring_str(s->pktout, ",");
+               ssh2_pkt_addstring_str(s->pktout, c->list[j]->name);
                cipherstr_started = 1;
            }
        }
        /* List client->server MAC algorithms. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        for (i = 0; i < s->nmacs; i++) {
-           ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
+           ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name);
            if (i < s->nmacs - 1)
-               ssh2_pkt_addstring_str(ssh, ",");
+               ssh2_pkt_addstring_str(s->pktout, ",");
        }
        /* List server->client MAC algorithms. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        for (i = 0; i < s->nmacs; i++) {
-           ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
+           ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name);
            if (i < s->nmacs - 1)
-               ssh2_pkt_addstring_str(ssh, ",");
+               ssh2_pkt_addstring_str(s->pktout, ",");
        }
        /* List client->server compression algorithms. */
-       ssh2_pkt_addstring_start(ssh);
-       for (i = 0; i < lenof(compressions) + 1; i++) {
-           const struct ssh_compress *c =
-               i == 0 ? s->preferred_comp : compressions[i - 1];
-           ssh2_pkt_addstring_str(ssh, c->name);
-           if (i < lenof(compressions))
-               ssh2_pkt_addstring_str(ssh, ",");
+       ssh2_pkt_addstring_start(s->pktout);
+       assert(lenof(compressions) > 1);
+       ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name);
+       for (i = 0; i < lenof(compressions); i++) {
+           const struct ssh_compress *c = compressions[i];
+           if (c != s->preferred_comp) {
+               ssh2_pkt_addstring_str(s->pktout, ",");
+               ssh2_pkt_addstring_str(s->pktout, c->name);
+           }
        }
        /* List server->client compression algorithms. */
-       ssh2_pkt_addstring_start(ssh);
-       for (i = 0; i < lenof(compressions) + 1; i++) {
-           const struct ssh_compress *c =
-               i == 0 ? s->preferred_comp : compressions[i - 1];
-           ssh2_pkt_addstring_str(ssh, c->name);
-           if (i < lenof(compressions))
-               ssh2_pkt_addstring_str(ssh, ",");
+       ssh2_pkt_addstring_start(s->pktout);
+       assert(lenof(compressions) > 1);
+       ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name);
+       for (i = 0; i < lenof(compressions); i++) {
+           const struct ssh_compress *c = compressions[i];
+           if (c != s->preferred_comp) {
+               ssh2_pkt_addstring_str(s->pktout, ",");
+               ssh2_pkt_addstring_str(s->pktout, c->name);
+           }
        }
        /* List client->server languages. Empty list. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        /* List server->client languages. Empty list. */
-       ssh2_pkt_addstring_start(ssh);
+       ssh2_pkt_addstring_start(s->pktout);
        /* First KEX packet does _not_ follow, because we're not that brave. */
-       ssh2_pkt_addbool(ssh, FALSE);
+       ssh2_pkt_addbool(s->pktout, FALSE);
        /* Reserved. */
-       ssh2_pkt_adduint32(ssh, 0);
+       ssh2_pkt_adduint32(s->pktout, 0);
     }
 
     ssh->exhash = ssh->exhashbase;
-    sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
+    sha_string(&ssh->exhash, s->pktout->data + 5, s->pktout->length - 5);
 
-    ssh2_pkt_send(ssh);
+    ssh2_pkt_send_noqueue(ssh, s->pktout);
 
-    if (!ispkt)
-       crWaitUntil(ispkt);
-    if (ssh->pktin.length > 5)
-       sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
+    if (!pktin)
+       crWaitUntil(pktin);
+    if (pktin->length > 5)
+       sha_string(&ssh->exhash, pktin->data + 5, pktin->length - 5);
 
     /*
      * Now examine the other side's KEXINIT to see what we're up
@@ -3892,9 +4399,9 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        char *str;
        int i, j, len;
 
-       if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
-           bombout((ssh,"expected key exchange packet from server"));
-           crReturn(0);
+       if (pktin->type != SSH2_MSG_KEXINIT) {
+           bombout(("expected key exchange packet from server"));
+           crStop(0);
        }
        ssh->kex = NULL;
        ssh->hostkey = NULL;
@@ -3904,8 +4411,8 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        s->scmac_tobe = NULL;
        s->cscomp_tobe = NULL;
        s->sccomp_tobe = NULL;
-       ssh->pktin.savedpos += 16;              /* skip garbage cookie */
-       ssh2_pkt_getstring(ssh, &str, &len);    /* key exchange algorithms */
+       pktin->savedpos += 16;          /* skip garbage cookie */
+       ssh_pkt_getstring(pktin, &str, &len);    /* key exchange algorithms */
        for (i = 0; i < lenof(kex_algs); i++) {
            if (kex_algs[i] == &ssh_diffiehellman_gex &&
                (ssh->remote_bugs & BUG_SSH2_DH_GEX))
@@ -3915,14 +4422,14 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                break;
            }
        }
-       ssh2_pkt_getstring(ssh, &str, &len);    /* host key algorithms */
+       ssh_pkt_getstring(pktin, &str, &len);    /* host key algorithms */
        for (i = 0; i < lenof(hostkey_algs); i++) {
            if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
                ssh->hostkey = hostkey_algs[i];
                break;
            }
        }
-       ssh2_pkt_getstring(ssh, &str, &len);    /* client->server cipher */
+       ssh_pkt_getstring(pktin, &str, &len);    /* client->server cipher */
        s->warn = 0;
        for (i = 0; i < s->n_preferred_ciphers; i++) {
            const struct ssh2_ciphers *c = s->preferred_ciphers[i];
@@ -3943,12 +4450,12 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            }
        }
        if (!s->cscipher_tobe) {
-           bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
+           bombout(("Couldn't agree a client-to-server cipher (available: %s)",
                     str ? str : "(null)"));
-           crReturn(0);
+           crStop(0);
        }
 
-       ssh2_pkt_getstring(ssh, &str, &len);    /* server->client cipher */
+       ssh_pkt_getstring(pktin, &str, &len);    /* server->client cipher */
        s->warn = 0;
        for (i = 0; i < s->n_preferred_ciphers; i++) {
            const struct ssh2_ciphers *c = s->preferred_ciphers[i];
@@ -3969,26 +4476,26 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            }
        }
        if (!s->sccipher_tobe) {
-           bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
+           bombout(("Couldn't agree a server-to-client cipher (available: %s)",
                     str ? str : "(null)"));
-           crReturn(0);
+           crStop(0);
        }
 
-       ssh2_pkt_getstring(ssh, &str, &len);    /* client->server mac */
+       ssh_pkt_getstring(pktin, &str, &len);    /* client->server mac */
        for (i = 0; i < s->nmacs; i++) {
            if (in_commasep_string(s->maclist[i]->name, str, len)) {
                s->csmac_tobe = s->maclist[i];
                break;
            }
        }
-       ssh2_pkt_getstring(ssh, &str, &len);    /* server->client mac */
+       ssh_pkt_getstring(pktin, &str, &len);    /* server->client mac */
        for (i = 0; i < s->nmacs; i++) {
            if (in_commasep_string(s->maclist[i]->name, str, len)) {
                s->scmac_tobe = s->maclist[i];
                break;
            }
        }
-       ssh2_pkt_getstring(ssh, &str, &len);  /* client->server compression */
+       ssh_pkt_getstring(pktin, &str, &len);  /* client->server compression */
        for (i = 0; i < lenof(compressions) + 1; i++) {
            const struct ssh_compress *c =
                i == 0 ? s->preferred_comp : compressions[i - 1];
@@ -3997,7 +4504,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                break;
            }
        }
-       ssh2_pkt_getstring(ssh, &str, &len);  /* server->client compression */
+       ssh_pkt_getstring(pktin, &str, &len);  /* server->client compression */
        for (i = 0; i < lenof(compressions) + 1; i++) {
            const struct ssh_compress *c =
                i == 0 ? s->preferred_comp : compressions[i - 1];
@@ -4037,17 +4544,21 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
         * much data.
         */
        s->pbits = 512 << ((s->nbits - 1) / 64);
-       ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
-       ssh2_pkt_adduint32(ssh, s->pbits);
-       ssh2_pkt_send(ssh);
-
-       crWaitUntil(ispkt);
-       if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
-           bombout((ssh,"expected key exchange group packet from server"));
-           crReturn(0);
+       s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
+       ssh2_pkt_adduint32(s->pktout, s->pbits);
+       ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+       crWaitUntil(pktin);
+       if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) {
+           bombout(("expected key exchange group packet from server"));
+           crStop(0);
+       }
+       s->p = ssh2_pkt_getmp(pktin);
+       s->g = ssh2_pkt_getmp(pktin);
+       if (!s->p || !s->g) {
+           bombout(("unable to read mp-ints from incoming group packet"));
+           crStop(0);
        }
-       s->p = ssh2_pkt_getmp(ssh);
-       s->g = ssh2_pkt_getmp(ssh);
        ssh->kex_ctx = dh_setup_group(s->p, s->g);
        s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
        s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
@@ -4063,18 +4574,22 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
      * Now generate and send e for Diffie-Hellman.
      */
     s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
-    ssh2_pkt_init(ssh, s->kex_init_value);
-    ssh2_pkt_addmp(ssh, s->e);
-    ssh2_pkt_send(ssh);
-
-    crWaitUntil(ispkt);
-    if (ssh->pktin.type != s->kex_reply_value) {
-       bombout((ssh,"expected key exchange reply packet from server"));
-       crReturn(0);
+    s->pktout = ssh2_pkt_init(s->kex_init_value);
+    ssh2_pkt_addmp(s->pktout, s->e);
+    ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+    crWaitUntil(pktin);
+    if (pktin->type != s->kex_reply_value) {
+       bombout(("expected key exchange reply packet from server"));
+       crStop(0);
+    }
+    ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
+    s->f = ssh2_pkt_getmp(pktin);
+    if (!s->f) {
+       bombout(("unable to parse key exchange reply packet"));
+       crStop(0);
     }
-    ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
-    s->f = ssh2_pkt_getmp(ssh);
-    ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
+    ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
 
     s->K = dh_find_K(ssh->kex_ctx, s->f);
 
@@ -4101,8 +4616,8 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     if (!s->hkey ||
        !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
                                 (char *)s->exchange_hash, 20)) {
-       bombout((ssh,"Server's host key did not match the signature supplied"));
-       crReturn(0);
+       bombout(("Server's host key did not match the signature supplied"));
+       crStop(0);
     }
 
     /*
@@ -4125,16 +4640,23 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Send SSH2_MSG_NEWKEYS.
      */
-    ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
-    ssh2_pkt_send(ssh);
+    s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS);
+    ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+    /*
+     * Now our end of the key exchange is complete, we can send all
+     * our queued higher-layer packets.
+     */
+    ssh->queueing = FALSE;
+    ssh2_pkt_queuesend(ssh);
 
     /*
      * Expect SSH2_MSG_NEWKEYS from server.
      */
-    crWaitUntil(ispkt);
-    if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
-       bombout((ssh,"expected new-keys packet from server"));
-       crReturn(0);
+    crWaitUntil(pktin);
+    if (pktin->type != SSH2_MSG_NEWKEYS) {
+       bombout(("expected new-keys packet from server"));
+       crStop(0);
     }
 
     /*
@@ -4196,12 +4718,22 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
              ssh->cscipher->text_name);
     logeventf(ssh, "Initialised %.200s server->client encryption",
              ssh->sccipher->text_name);
+    logeventf(ssh, "Initialised %.200s client->server MAC algorithm",
+             ssh->csmac->text_name);
+    logeventf(ssh, "Initialised %.200s server->client MAC algorithm",
+             ssh->scmac->text_name);
     if (ssh->cscomp->text_name)
        logeventf(ssh, "Initialised %s compression",
                  ssh->cscomp->text_name);
     if (ssh->sccomp->text_name)
        logeventf(ssh, "Initialised %s decompression",
                  ssh->sccomp->text_name);
+    freebn(s->f);
+    freebn(s->K);
+    if (ssh->kex == &ssh_diffiehellman_gex) {
+       freebn(s->g);
+       freebn(s->p);
+    }
 
     /*
      * If this is the first key exchange phase, we must pass the
@@ -4212,7 +4744,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
      * it would only confuse the layer above.
      */
     if (!s->first_kex) {
-       crReturn(0);
+       crReturn(1);
     }
     s->first_kex = 0;
 
@@ -4222,7 +4754,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
      * transport. If we ever see a KEXINIT, we must go back to the
      * start.
      */
-    while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
+    while (!(pktin && pktin->type == SSH2_MSG_KEXINIT)) {
        crReturn(1);
     }
     logevent("Server initiated key re-exchange");
@@ -4246,6 +4778,7 @@ static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
 static int ssh2_try_send(struct ssh_channel *c)
 {
     Ssh ssh = c->ssh;
+    struct Packet *pktout;
 
     while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
        int len;
@@ -4255,11 +4788,13 @@ static int ssh2_try_send(struct ssh_channel *c)
            len = c->v.v2.remwindow;
        if ((unsigned)len > c->v.v2.remmaxpkt)
            len = c->v.v2.remmaxpkt;
-       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
-       ssh2_pkt_adduint32(ssh, c->remoteid);
-       ssh2_pkt_addstring_start(ssh);
-       ssh2_pkt_addstring_data(ssh, data, len);
-       ssh2_pkt_send(ssh);
+       pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
+       ssh2_pkt_adduint32(pktout, c->remoteid);
+       dont_log_data(ssh, pktout, PKTLOG_OMIT);
+       ssh2_pkt_addstring_start(pktout);
+       ssh2_pkt_addstring_data(pktout, data, len);
+       end_log_omission(ssh, pktout);
+       ssh2_pkt_send(ssh, pktout);
        bufchain_consume(&c->v.v2.outbuffer, len);
        c->v.v2.remwindow -= len;
     }
@@ -4287,18 +4822,30 @@ static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
        return;
 
     if (newwin > c->v.v2.locwindow) {
-       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
-       ssh2_pkt_adduint32(ssh, c->remoteid);
-       ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
-       ssh2_pkt_send(ssh);
+       struct Packet *pktout;
+
+       pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
+       ssh2_pkt_adduint32(pktout, c->remoteid);
+       ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
+       ssh2_pkt_send(ssh, pktout);
        c->v.v2.locwindow = newwin;
     }
 }
 
+void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin)
+{
+    unsigned i = ssh_pkt_getuint32(pktin);
+    struct ssh_channel *c;
+    c = find234(ssh->channels, &i, ssh_channelfind);
+    if (c && !c->closes)
+       c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
+}
+
 /*
  * Handle the SSH2 userauth and connection layers.
  */
-static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
+static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
+                            struct Packet *pktin)
 {
     struct do_ssh2_authconn_state {
        enum {
@@ -4322,7 +4869,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        int num_prompts, curr_prompt, echo;
        char username[100];
        int got_username;
-       char pwprompt[200];
+       char pwprompt[512];
        char password[100];
        void *publickey_blob;
        int publickey_bloblen;
@@ -4335,6 +4882,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
        int siglen, retlen, len;
        char *q, *agentreq, *ret;
        int try_send;
+       int num_env, env_left, env_ok;
+       struct Packet *pktout;
     };
     crState(do_ssh2_authconn_state);
 
@@ -4343,13 +4892,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Request userauth protocol, and await a response to it.
      */
-    ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
-    ssh2_pkt_addstring(ssh, "ssh-userauth");
-    ssh2_pkt_send(ssh);
-    crWaitUntilV(ispkt);
-    if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
-       bombout((ssh,"Server refused user authentication protocol"));
-       crReturnV;
+    s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
+    ssh2_pkt_addstring(s->pktout, "ssh-userauth");
+    ssh2_pkt_send(ssh, s->pktout);
+    crWaitUntilV(pktin);
+    if (pktin->type != SSH2_MSG_SERVICE_ACCEPT) {
+       bombout(("Server refused user authentication protocol"));
+       crStopV;
     }
 
     /*
@@ -4388,7 +4937,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
             * with change_username turned off we don't try to get
             * it again.
             */
-       } else if ((flags & FLAG_INTERACTIVE) && !*ssh->cfg.username) {
+       } else if (!*ssh->cfg.username) {
            if (ssh_get_line && !ssh_getline_pw_only) {
                if (!ssh_get_line("login as: ",
                                  s->username, sizeof(s->username), FALSE)) {
@@ -4397,8 +4946,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * Terminate.
                     */
                    logevent("No username provided. Abandoning session.");
-                   ssh->state = SSH_STATE_CLOSED;
-                   crReturnV;
+                    ssh_closing((Plug)ssh, NULL, 0, 0);
+                   crStopV;
                }
            } else {
                int ret;               /* need not be saved across crReturn */
@@ -4406,7 +4955,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                ssh->send_ok = 1;
                setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
                do {
-                   crWaitUntilV(!ispkt);
+                   crWaitUntilV(!pktin);
                    ret = process_userpass_input(ssh, in, inlen);
                } while (ret == 0);
                if (ret < 0)
@@ -4433,11 +4982,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
         */
        ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
 
-       ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-       ssh2_pkt_addstring(ssh, s->username);
-       ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
-       ssh2_pkt_addstring(ssh, "none");    /* method */
-       ssh2_pkt_send(ssh);
+       s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+       ssh2_pkt_addstring(s->pktout, s->username);
+       ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */
+       ssh2_pkt_addstring(s->pktout, "none");    /* method */
+       ssh2_pkt_send(ssh, s->pktout);
        s->type = AUTH_TYPE_NONE;
        s->gotit = FALSE;
        s->we_are_in = FALSE;
@@ -4455,7 +5004,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            if (keytype == SSH_KEYTYPE_SSH2) {
                s->publickey_blob =
                    ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL,
-                                        &s->publickey_bloblen);
+                                        &s->publickey_bloblen, NULL);
            } else {
                char *msgbuf;
                logeventf(ssh, "Unable to use this key file (%s)",
@@ -4476,8 +5025,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
             * Wait for the result of the last authentication request.
             */
            if (!s->gotit)
-               crWaitUntilV(ispkt);
-           while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
+               crWaitUntilV(pktin);
+           while (pktin->type == SSH2_MSG_USERAUTH_BANNER) {
                char *banner;
                int size;
                /*
@@ -4489,20 +5038,20 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 * output of (say) plink.)
                 */
                if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
-                   ssh2_pkt_getstring(ssh, &banner, &size);
+                   ssh_pkt_getstring(pktin, &banner, &size);
                    if (banner)
                        c_write_untrusted(ssh, banner, size);
                }
-               crWaitUntilV(ispkt);
+               crWaitUntilV(pktin);
            }
-           if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
+           if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) {
                logevent("Access granted");
                s->we_are_in = TRUE;
                break;
            }
 
            if (s->kbd_inter_running &&
-               ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
+               pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
                /*
                 * This is either a further set-of-prompts packet
                 * in keyboard-interactive authentication, or it's
@@ -4512,10 +5061,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 */
                if (!s->gotit)
                    s->curr_prompt = 0;
-           } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
-               bombout((ssh,"Strange packet received during authentication: type %d",
-                        ssh->pktin.type));
-               crReturnV;
+           } else if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) {
+               bombout(("Strange packet received during authentication: type %d",
+                        pktin->type));
+               crStopV;
            }
 
            s->gotit = FALSE;
@@ -4525,12 +5074,12 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
             * we can look at the string in it and know what we can
             * helpfully try next.
             */
-           if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
+           if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) {
                char *methods;
                int methlen;
-               ssh2_pkt_getstring(ssh, &methods, &methlen);
+               ssh_pkt_getstring(pktin, &methods, &methlen);
                s->kbd_inter_running = FALSE;
-               if (!ssh2_pkt_getbool(ssh)) {
+               if (!ssh2_pkt_getbool(pktin)) {
                    /*
                     * We have received an unequivocal Access
                     * Denied. This can translate to a variety of
@@ -4550,7 +5099,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * Additionally, if we'd just tried password
                     * authentication, we should break out of this
                     * whole loop so as to go back to the username
-                    * prompt.
+                    * prompt (iff we're configured to allow
+                    * username change attempts).
                     */
                    if (s->type == AUTH_TYPE_NONE) {
                        /* do nothing */
@@ -4564,7 +5114,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    } else {
                        c_write_str(ssh, "Access denied\r\n");
                        logevent("Access denied");
-                       if (s->type == AUTH_TYPE_PASSWORD) {
+                       if (s->type == AUTH_TYPE_PASSWORD &&
+                           ssh->cfg.change_username) {
+                           /* XXX perhaps we should allow
+                            * keyboard-interactive to do this too? */
                            s->we_are_in = FALSE;
                            break;
                        }
@@ -4584,6 +5137,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
            s->method = 0;
            ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
+           s->need_pw = FALSE;
 
            /*
             * Most password/passphrase prompts will be
@@ -4611,7 +5165,19 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                /* Request the keys held by the agent. */
                PUT_32BIT(s->request, 1);
                s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
-               agent_query(s->request, 5, &r, &s->responselen);
+               if (!agent_query(s->request, 5, &r, &s->responselen,
+                                ssh_agent_callback, ssh)) {
+                   do {
+                       crReturnV;
+                       if (pktin) {
+                           bombout(("Unexpected data from server while"
+                                    " waiting for agent response"));
+                           crStopV;
+                       }
+                   } while (pktin || inlen > 0);
+                   r = ssh->agent_response;
+                   s->responselen = ssh->agent_response_len;
+               }
                s->response = (unsigned char *) r;
                if (s->response && s->responselen >= 5 &&
                    s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
@@ -4648,19 +5214,19 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        s->p += 4;
                        s->commentp = (char *)s->p;
                        s->p += s->commentlen;
-                       ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-                       ssh2_pkt_addstring(ssh, s->username);
-                       ssh2_pkt_addstring(ssh, "ssh-connection");      /* service requested */
-                       ssh2_pkt_addstring(ssh, "publickey");   /* method */
-                       ssh2_pkt_addbool(ssh, FALSE);   /* no signature included */
-                       ssh2_pkt_addstring_start(ssh);
-                       ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
-                       ssh2_pkt_addstring_start(ssh);
-                       ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
-                       ssh2_pkt_send(ssh);
-
-                       crWaitUntilV(ispkt);
-                       if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
+                       s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+                       ssh2_pkt_addstring(s->pktout, s->username);
+                       ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
+                       ssh2_pkt_addstring(s->pktout, "publickey");     /* method */
+                       ssh2_pkt_addbool(s->pktout, FALSE);     /* no signature included */
+                       ssh2_pkt_addstring_start(s->pktout);
+                       ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
+                       ssh2_pkt_addstring_start(s->pktout);
+                       ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
+                       ssh2_pkt_send(ssh, s->pktout);
+
+                       crWaitUntilV(pktin);
+                       if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
                            logevent("Key refused");
                            continue;
                        }
@@ -4676,17 +5242,17 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                         * Server is willing to accept the key.
                         * Construct a SIGN_REQUEST.
                         */
-                       ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-                       ssh2_pkt_addstring(ssh, s->username);
-                       ssh2_pkt_addstring(ssh, "ssh-connection");      /* service requested */
-                       ssh2_pkt_addstring(ssh, "publickey");   /* method */
-                       ssh2_pkt_addbool(ssh, TRUE);
-                       ssh2_pkt_addstring_start(ssh);
-                       ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
-                       ssh2_pkt_addstring_start(ssh);
-                       ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
-
-                       s->siglen = ssh->pktout.length - 5 + 4 + 20;
+                       s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+                       ssh2_pkt_addstring(s->pktout, s->username);
+                       ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
+                       ssh2_pkt_addstring(s->pktout, "publickey");     /* method */
+                       ssh2_pkt_addbool(s->pktout, TRUE);
+                       ssh2_pkt_addstring_start(s->pktout);
+                       ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen);
+                       ssh2_pkt_addstring_start(s->pktout);
+                       ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen);
+
+                       s->siglen = s->pktout->length - 5 + 4 + 20;
                         if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
                             s->siglen -= 4;
                        s->len = 1;       /* message type */
@@ -4710,21 +5276,36 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                         }
                        memcpy(s->q, ssh->v2_session_id, 20);
                        s->q += 20;
-                       memcpy(s->q, ssh->pktout.data + 5,
-                              ssh->pktout.length - 5);
-                       s->q += ssh->pktout.length - 5;
+                       memcpy(s->q, s->pktout->data + 5,
+                              s->pktout->length - 5);
+                       s->q += s->pktout->length - 5;
                        /* And finally the (zero) flags word. */
                        PUT_32BIT(s->q, 0);
-                       agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
+                       if (!agent_query(s->agentreq, s->len + 4,
+                                        &vret, &s->retlen,
+                                        ssh_agent_callback, ssh)) {
+                           do {
+                               crReturnV;
+                               if (pktin) {
+                                   bombout(("Unexpected data from server"
+                                            " while waiting for agent"
+                                            " response"));
+                                   crStopV;
+                               }
+                           } while (pktin || inlen > 0);
+                           vret = ssh->agent_response;
+                           s->retlen = ssh->agent_response_len;
+                       }
                        s->ret = vret;
                        sfree(s->agentreq);
                        if (s->ret) {
                            if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
                                logevent("Sending Pageant's response");
-                               ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
+                               ssh2_add_sigblob(ssh, s->pktout,
+                                                s->pkblob, s->pklen,
                                                 s->ret + 9,
                                                 GET_32BIT(s->ret + 5));
-                               ssh2_pkt_send(ssh);
+                               ssh2_pkt_send(ssh, s->pktout);
                                s->authed = TRUE;
                                break;
                            } else {
@@ -4737,6 +5318,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    if (s->authed)
                        continue;
                }
+               sfree(s->response);
            }
 
            if (!s->method && s->can_pubkey && s->publickey_blob
@@ -4759,22 +5341,23 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                pub_blob =
                    (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile,
                                                          &algorithm,
-                                                         &pub_blob_len);
+                                                         &pub_blob_len,
+                                                         NULL);
                if (pub_blob) {
-                   ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-                   ssh2_pkt_addstring(ssh, s->username);
-                   ssh2_pkt_addstring(ssh, "ssh-connection");  /* service requested */
-                   ssh2_pkt_addstring(ssh, "publickey");       /* method */
-                   ssh2_pkt_addbool(ssh, FALSE);       /* no signature included */
-                   ssh2_pkt_addstring(ssh, algorithm);
-                   ssh2_pkt_addstring_start(ssh);
-                   ssh2_pkt_addstring_data(ssh, (char *)pub_blob,
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+                   ssh2_pkt_addstring(s->pktout, s->username);
+                   ssh2_pkt_addstring(s->pktout, "ssh-connection");    /* service requested */
+                   ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
+                   ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */
+                   ssh2_pkt_addstring(s->pktout, algorithm);
+                   ssh2_pkt_addstring_start(s->pktout);
+                   ssh2_pkt_addstring_data(s->pktout, (char *)pub_blob,
                                            pub_blob_len);
-                   ssh2_pkt_send(ssh);
-                   logevent("Offered public key");     /* FIXME */
+                   ssh2_pkt_send(ssh, s->pktout);
+                   logevent("Offered public key");
 
-                   crWaitUntilV(ispkt);
-                   if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
+                   crWaitUntilV(pktin);
+                   if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) {
                        s->gotit = TRUE;
                        s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
                        continue;      /* key refused; give up on it */
@@ -4793,9 +5376,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    } else {
                        s->need_pw = FALSE;
                    }
-                   c_write_str(ssh, "Authenticating with public key \"");
-                   c_write_str(ssh, comment);
-                   c_write_str(ssh, "\"\r\n");
+                   if (flags & FLAG_VERBOSE) {
+                       c_write_str(ssh, "Authenticating with public key \"");
+                       c_write_str(ssh, comment);
+                       c_write_str(ssh, "\"\r\n");
+                   }
                    s->method = AUTH_PUBLICKEY_FILE;
                }
            }
@@ -4808,17 +5393,17 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
                ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
 
-               ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-               ssh2_pkt_addstring(ssh, s->username);
-               ssh2_pkt_addstring(ssh, "ssh-connection");      /* service requested */
-               ssh2_pkt_addstring(ssh, "keyboard-interactive");        /* method */
-               ssh2_pkt_addstring(ssh, ""); /* lang */
-               ssh2_pkt_addstring(ssh, "");
-               ssh2_pkt_send(ssh);
-
-               crWaitUntilV(ispkt);
-               if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
-                   if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+               ssh2_pkt_addstring(s->pktout, s->username);
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
+               ssh2_pkt_addstring(s->pktout, "keyboard-interactive");  /* method */
+               ssh2_pkt_addstring(s->pktout, ""); /* lang */
+               ssh2_pkt_addstring(s->pktout, "");
+               ssh2_pkt_send(ssh, s->pktout);
+
+               crWaitUntilV(pktin);
+               if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
+                   if (pktin->type == SSH2_MSG_USERAUTH_FAILURE)
                        s->gotit = TRUE;
                    logevent("Keyboard-interactive authentication refused");
                    s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
@@ -4846,9 +5431,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    char *name, *inst, *lang;
                    int name_len, inst_len, lang_len;
 
-                   ssh2_pkt_getstring(ssh, &name, &name_len);
-                   ssh2_pkt_getstring(ssh, &inst, &inst_len);
-                   ssh2_pkt_getstring(ssh, &lang, &lang_len);
+                   ssh_pkt_getstring(pktin, &name, &name_len);
+                   ssh_pkt_getstring(pktin, &inst, &inst_len);
+                   ssh_pkt_getstring(pktin, &lang, &lang_len);
                    if (name_len > 0) {
                        c_write_untrusted(ssh, name, name_len);
                        c_write_str(ssh, "\r\n");
@@ -4857,7 +5442,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        c_write_untrusted(ssh, inst, inst_len);
                        c_write_str(ssh, "\r\n");
                    }
-                   s->num_prompts = ssh2_pkt_getuint32(ssh);
+                   s->num_prompts = ssh_pkt_getuint32(pktin);
                }
 
                /*
@@ -4868,16 +5453,23 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    char *prompt;
                    int prompt_len;
 
-                   ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
+                   ssh_pkt_getstring(pktin, &prompt, &prompt_len);
                    if (prompt_len > 0) {
-                       strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
-                       s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
-                                   prompt_len : sizeof(s->pwprompt)-1] = '\0';
+                       static const char trunc[] = "<prompt truncated>: ";
+                       static const int prlen = sizeof(s->pwprompt) -
+                                                lenof(trunc);
+                       if (prompt_len > prlen) {
+                           memcpy(s->pwprompt, prompt, prlen);
+                           strcpy(s->pwprompt + prlen, trunc);
+                       } else {
+                           memcpy(s->pwprompt, prompt, prompt_len);
+                           s->pwprompt[prompt_len] = '\0';
+                       }
                    } else {
                        strcpy(s->pwprompt,
                               "<server failed to send prompt>: ");
                    }
-                   s->echo = ssh2_pkt_getbool(ssh);
+                   s->echo = ssh2_pkt_getbool(pktin);
                    s->need_pw = TRUE;
                } else
                    s->need_pw = FALSE;
@@ -4902,17 +5494,17 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                         * command line which has already failed to
                         * work). Terminate.
                         */
-                       ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
-                       ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
-                       ssh2_pkt_addstring(ssh, "No more passwords available"
+                       s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
+                       ssh2_pkt_adduint32(s->pktout,SSH2_DISCONNECT_BY_APPLICATION);
+                       ssh2_pkt_addstring(s->pktout, "No more passwords available"
                                           " to try");
-                       ssh2_pkt_addstring(ssh, "en");  /* language tag */
-                       ssh2_pkt_send(ssh);
+                       ssh2_pkt_addstring(s->pktout, "en");    /* language tag */
+                       ssh2_pkt_send_noqueue(ssh, s->pktout);
                        logevent("Unable to authenticate");
                        connection_fatal(ssh->frontend,
                                         "Unable to authenticate");
-                       ssh->state = SSH_STATE_CLOSED;
-                       crReturnV;
+                        ssh_closing((Plug)ssh, NULL, 0, 0);
+                       crStopV;
                    }
                } else {
                    int ret;           /* need not be saved across crReturn */
@@ -4922,7 +5514,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    setup_userpass_input(ssh, s->password,
                                         sizeof(s->password), s->echo);
                    do {
-                       crWaitUntilV(!ispkt);
+                       crWaitUntilV(!pktin);
                        ret = process_userpass_input(ssh, in, inlen);
                    } while (ret == 0);
                    if (ret < 0)
@@ -4936,22 +5528,26 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 * We have our passphrase. Now try the actual authentication.
                 */
                struct ssh2_userkey *key;
+               const char *error = NULL;
 
-               key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password);
+               key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password,
+                                       &error);
                if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
                    if (key == SSH2_WRONG_PASSPHRASE) {
                        c_write_str(ssh, "Wrong passphrase\r\n");
                        s->tried_pubkey_config = FALSE;
                    } else {
-                       c_write_str(ssh, "Unable to load private key\r\n");
+                       c_write_str(ssh, "Unable to load private key (");
+                       c_write_str(ssh, error);
+                       c_write_str(ssh, ")\r\n");
                        s->tried_pubkey_config = TRUE;
                    }
                    /* Send a spurious AUTH_NONE to return to the top. */
-                   ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-                   ssh2_pkt_addstring(ssh, s->username);
-                   ssh2_pkt_addstring(ssh, "ssh-connection");  /* service requested */
-                   ssh2_pkt_addstring(ssh, "none");    /* method */
-                   ssh2_pkt_send(ssh);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+                   ssh2_pkt_addstring(s->pktout, s->username);
+                   ssh2_pkt_addstring(s->pktout, "ssh-connection");    /* service requested */
+                   ssh2_pkt_addstring(s->pktout, "none");      /* method */
+                   ssh2_pkt_send(ssh, s->pktout);
                    s->type = AUTH_TYPE_NONE;
                } else {
                    unsigned char *pkblob, *sigblob, *sigdata;
@@ -4963,15 +5559,15 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * has announced that it's willing to accept it.
                     * Hallelujah. Generate a signature and send it.
                     */
-                   ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-                   ssh2_pkt_addstring(ssh, s->username);
-                   ssh2_pkt_addstring(ssh, "ssh-connection");  /* service requested */
-                   ssh2_pkt_addstring(ssh, "publickey");       /* method */
-                   ssh2_pkt_addbool(ssh, TRUE);
-                   ssh2_pkt_addstring(ssh, key->alg->name);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+                   ssh2_pkt_addstring(s->pktout, s->username);
+                   ssh2_pkt_addstring(s->pktout, "ssh-connection");    /* service requested */
+                   ssh2_pkt_addstring(s->pktout, "publickey"); /* method */
+                   ssh2_pkt_addbool(s->pktout, TRUE);
+                   ssh2_pkt_addstring(s->pktout, key->alg->name);
                    pkblob = key->alg->public_blob(key->data, &pkblob_len);
-                   ssh2_pkt_addstring_start(ssh);
-                   ssh2_pkt_addstring_data(ssh, (char *)pkblob, pkblob_len);
+                   ssh2_pkt_addstring_start(s->pktout);
+                   ssh2_pkt_addstring_data(s->pktout, (char *)pkblob, pkblob_len);
 
                    /*
                     * The data to be signed is:
@@ -4981,7 +5577,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * followed by everything so far placed in the
                     * outgoing packet.
                     */
-                   sigdata_len = ssh->pktout.length - 5 + 4 + 20;
+                   sigdata_len = s->pktout->length - 5 + 4 + 20;
                     if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)
                         sigdata_len -= 4;
                    sigdata = snewn(sigdata_len, unsigned char);
@@ -4991,20 +5587,21 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                         p += 4;
                     }
                    memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20;
-                   memcpy(sigdata+p, ssh->pktout.data + 5,
-                          ssh->pktout.length - 5);
-                    p += ssh->pktout.length - 5;
+                   memcpy(sigdata+p, s->pktout->data + 5,
+                          s->pktout->length - 5);
+                    p += s->pktout->length - 5;
                     assert(p == sigdata_len);
                    sigblob = key->alg->sign(key->data, (char *)sigdata,
                                             sigdata_len, &sigblob_len);
-                   ssh2_add_sigblob(ssh, pkblob, pkblob_len,
+                   ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len,
                                     sigblob, sigblob_len);
                    sfree(pkblob);
                    sfree(sigblob);
                    sfree(sigdata);
 
-                   ssh2_pkt_send(ssh);
+                   ssh2_pkt_send(ssh, s->pktout);
                    s->type = AUTH_TYPE_PUBLICKEY;
+                   key->alg->freekey(key->data);
                }
            } else if (s->method == AUTH_PASSWORD) {
                /*
@@ -5021,14 +5618,16 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 * that probably doesn't have much to worry about from
                 * people who find out how long their password is!
                 */
-               ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
-               ssh2_pkt_addstring(ssh, s->username);
-               ssh2_pkt_addstring(ssh, "ssh-connection");      /* service requested */
-               ssh2_pkt_addstring(ssh, "password");
-               ssh2_pkt_addbool(ssh, FALSE);
-               ssh2_pkt_addstring(ssh, s->password);
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+               ssh2_pkt_addstring(s->pktout, s->username);
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");        /* service requested */
+               ssh2_pkt_addstring(s->pktout, "password");
+               ssh2_pkt_addbool(s->pktout, FALSE);
+               dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
+               ssh2_pkt_addstring(s->pktout, s->password);
                memset(s->password, 0, sizeof(s->password));
-               ssh2_pkt_defer(ssh);
+               end_log_omission(ssh, s->pktout);
+               ssh2_pkt_defer(ssh, s->pktout);
                /*
                 * We'll include a string that's an exact multiple of the
                 * cipher block size. If the cipher is NULL for some
@@ -5054,29 +5653,31 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        stringlen -= 
                            ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
                    }
-                   ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
-                   ssh2_pkt_addstring_start(ssh);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
+                   ssh2_pkt_addstring_start(s->pktout);
                    for (i = 0; i < stringlen; i++) {
                        char c = (char) random_byte();
-                       ssh2_pkt_addstring_data(ssh, &c, 1);
+                       ssh2_pkt_addstring_data(s->pktout, &c, 1);
                    }
-                   ssh2_pkt_defer(ssh);
+                   ssh2_pkt_defer(ssh, s->pktout);
                }
                ssh_pkt_defersend(ssh);
                logevent("Sent password");
                s->type = AUTH_TYPE_PASSWORD;
            } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
                if (s->curr_prompt == 0) {
-                   ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
-                   ssh2_pkt_adduint32(ssh, s->num_prompts);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
+                   ssh2_pkt_adduint32(s->pktout, s->num_prompts);
                }
                if (s->need_pw) {      /* only add pw if we just got one! */
-                   ssh2_pkt_addstring(ssh, s->password);
+                   dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
+                   ssh2_pkt_addstring(s->pktout, s->password);
                    memset(s->password, 0, sizeof(s->password));
+                   end_log_omission(ssh, s->pktout);
                    s->curr_prompt++;
                }
                if (s->curr_prompt >= s->num_prompts) {
-                   ssh2_pkt_send(ssh);
+                   ssh2_pkt_send(ssh, s->pktout);
                } else {
                    /*
                     * If there are prompts remaining, we set
@@ -5094,14 +5695,14 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                            " left to try!\r\n");
                logevent("No supported authentications offered."
                         " Disconnecting");
-               ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
-               ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
-               ssh2_pkt_addstring(ssh, "No supported authentication"
+               s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
+               ssh2_pkt_adduint32(s->pktout, SSH2_DISCONNECT_BY_APPLICATION);
+               ssh2_pkt_addstring(s->pktout, "No supported authentication"
                                   " methods available");
-               ssh2_pkt_addstring(ssh, "en");  /* language tag */
-               ssh2_pkt_send(ssh);
-               ssh->state = SSH_STATE_CLOSED;
-               crReturnV;
+               ssh2_pkt_addstring(s->pktout, "en");    /* language tag */
+               ssh2_pkt_send_noqueue(ssh, s->pktout);
+                ssh_closing((Plug)ssh, NULL, 0, 0);
+               crStopV;
            }
        }
     } while (!s->we_are_in);
@@ -5112,75 +5713,77 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
      * point; there's no need to send SERVICE_REQUEST.
      */
 
+    ssh->channels = newtree234(ssh_channelcmp);
+
     /*
-     * So now create a channel with a session in it.
+     * Set up handlers for some connection protocol messages, so we
+     * don't have to handle them repeatedly in this coroutine.
      */
-    ssh->channels = newtree234(ssh_channelcmp);
-    ssh->mainchan = snew(struct ssh_channel);
-    ssh->mainchan->ssh = ssh;
-    ssh->mainchan->localid = alloc_channel_id(ssh);
-    ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
-    ssh2_pkt_addstring(ssh, "session");
-    ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
-    ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
-    ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
-    ssh2_pkt_adduint32(ssh, 0x4000UL);      /* our max pkt size */
-    ssh2_pkt_send(ssh);
-    crWaitUntilV(ispkt);
-    if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
-       bombout((ssh,"Server refused to open a session"));
-       crReturnV;
-       /* FIXME: error data comes back in FAILURE packet */
-    }
-    if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
-       bombout((ssh,"Server's channel confirmation cited wrong channel"));
-       crReturnV;
-    }
-    ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
-    ssh->mainchan->type = CHAN_MAINSESSION;
-    ssh->mainchan->closes = 0;
-    ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
-    ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
-    bufchain_init(&ssh->mainchan->v.v2.outbuffer);
-    add234(ssh->channels, ssh->mainchan);
-    logevent("Opened channel for session");
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] =
+       ssh2_msg_channel_window_adjust;
+
+    /*
+     * Create the main session channel.
+     */
+    if (!ssh->cfg.ssh_no_shell) {
+       ssh->mainchan = snew(struct ssh_channel);
+       ssh->mainchan->ssh = ssh;
+       ssh->mainchan->localid = alloc_channel_id(ssh);
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
+       ssh2_pkt_addstring(s->pktout, "session");
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->localid);
+       ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->v.v2.locwindow);/* our window size */
+       ssh2_pkt_adduint32(s->pktout, 0x4000UL);      /* our max pkt size */
+       ssh2_pkt_send(ssh, s->pktout);
+       crWaitUntilV(pktin);
+       if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
+           bombout(("Server refused to open a session"));
+           crStopV;
+           /* FIXME: error data comes back in FAILURE packet */
+       }
+       if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) {
+           bombout(("Server's channel confirmation cited wrong channel"));
+           crStopV;
+       }
+       ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
+       ssh->mainchan->type = CHAN_MAINSESSION;
+       ssh->mainchan->closes = 0;
+       ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin);
+       ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
+       bufchain_init(&ssh->mainchan->v.v2.outbuffer);
+       add234(ssh->channels, ssh->mainchan);
+       update_specials_menu(ssh->frontend);
+       logevent("Opened channel for session");
+    } else
+       ssh->mainchan = NULL;
 
     /*
      * Potentially enable X11 forwarding.
      */
-    if (ssh->cfg.x11_forward) {
+    if (ssh->mainchan && ssh->cfg.x11_forward) {
        char proto[20], data[64];
        logevent("Requesting X11 forwarding");
        ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
                                       data, sizeof(data), ssh->cfg.x11_auth);
         x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
-       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
-       ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
-       ssh2_pkt_addstring(ssh, "x11-req");
-       ssh2_pkt_addbool(ssh, 1);              /* want reply */
-       ssh2_pkt_addbool(ssh, 0);              /* many connections */
-       ssh2_pkt_addstring(ssh, proto);
-       ssh2_pkt_addstring(ssh, data);
-       ssh2_pkt_adduint32(ssh, x11_get_screen_number(ssh->cfg.x11_display));
-       ssh2_pkt_send(ssh);
-
-       do {
-           crWaitUntilV(ispkt);
-           if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
-               struct ssh_channel *c;
-               c = find234(ssh->channels, &i, ssh_channelfind);
-               if (!c)
-                   continue;          /* nonexistent channel */
-               c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
-           }
-       } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
-
-       if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
-           if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
-               bombout((ssh,"Unexpected response to X11 forwarding request:"
-                        " packet type %d", ssh->pktin.type));
-               crReturnV;
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
+       ssh2_pkt_addstring(s->pktout, "x11-req");
+       ssh2_pkt_addbool(s->pktout, 1);        /* want reply */
+       ssh2_pkt_addbool(s->pktout, 0);        /* many connections */
+       ssh2_pkt_addstring(s->pktout, proto);
+       ssh2_pkt_addstring(s->pktout, data);
+       ssh2_pkt_adduint32(s->pktout, x11_get_screen_number(ssh->cfg.x11_display));
+       ssh2_pkt_send(ssh, s->pktout);
+
+       crWaitUntilV(pktin);
+
+       if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
+           if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
+               bombout(("Unexpected response to X11 forwarding request:"
+                        " packet type %d", pktin->type));
+               crStopV;
            }
            logevent("X11 forwarding refused");
        } else {
@@ -5223,30 +5826,36 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
            }
            sports[n] = 0;
-           if (*ssh->portfwd_strptr == '\t')
-               ssh->portfwd_strptr++;
-           n = 0;
-           while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
-               if (n < 255) host[n++] = *ssh->portfwd_strptr++;
-           }
-           host[n] = 0;
-           if (*ssh->portfwd_strptr == ':')
+           if (type != 'D') {
+               if (*ssh->portfwd_strptr == '\t')
+                   ssh->portfwd_strptr++;
+               n = 0;
+               while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
+                   if (n < 255) host[n++] = *ssh->portfwd_strptr++;
+               }
+               host[n] = 0;
+               if (*ssh->portfwd_strptr == ':')
+                   ssh->portfwd_strptr++;
+               n = 0;
+               while (*ssh->portfwd_strptr) {
+                   if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
+               }
+               dports[n] = 0;
                ssh->portfwd_strptr++;
-           n = 0;
-           while (*ssh->portfwd_strptr) {
-               if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
-           }
-           dports[n] = 0;
-           ssh->portfwd_strptr++;
-           dport = atoi(dports);
-           dserv = 0;
-           if (dport == 0) {
-               dserv = 1;
-               dport = net_service_lookup(dports);
-               if (!dport) {
-                   logeventf(ssh, "Service lookup failed for destination"
-                             " port \"%s\"", dports);
+               dport = atoi(dports);
+               dserv = 0;
+               if (dport == 0) {
+                   dserv = 1;
+                   dport = net_service_lookup(dports);
+                   if (!dport) {
+                       logeventf(ssh, "Service lookup failed for destination"
+                                 " port \"%s\"", dports);
+                   }
                }
+           } else {
+               while (*ssh->portfwd_strptr) ssh->portfwd_strptr++;
+               dport = dserv = -1;
+               ssh->portfwd_strptr++; /* eat the NUL and move to next one */
            }
            sport = atoi(sports);
            sserv = 0;
@@ -5259,18 +5868,41 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                }
            }
            if (sport && dport) {
+               /* Set up a description of the source port. */
+               static char *sportdesc;
+               sportdesc = dupprintf("%.*s%.*s%.*s%.*s%d%.*s",
+                       (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
+                       (int)(*saddr?1:0), ":",
+                       (int)(sserv ? strlen(sports) : 0), sports,
+                       sserv, "(", sport, sserv, ")");
                if (type == 'L') {
-                   pfd_addforward(host, dport, *saddr ? saddr : NULL,
-                                  sport, ssh, &ssh->cfg);
-                   logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
-                             " forwarding to %s:%.*s%.*s%d%.*s",
-                             (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
-                             (int)(*saddr?1:0), ":",
-                             (int)(sserv ? strlen(sports) : 0), sports,
-                             sserv, "(", sport, sserv, ")",
-                             host,
-                             (int)(dserv ? strlen(dports) : 0), dports,
-                             dserv, "(", dport, dserv, ")");
+                   /* Verbose description of the destination port */
+                   char *dportdesc = dupprintf("%s:%.*s%.*s%d%.*s",
+                           host,
+                           (int)(dserv ? strlen(dports) : 0), dports,
+                           dserv, "(", dport, dserv, ")");
+                   const char *err = pfd_addforward(host, dport,
+                                                    *saddr ? saddr : NULL,
+                                                    sport, ssh, &ssh->cfg);
+                   if (err) {
+                       logeventf(ssh, "Local port %s forward to %s"
+                                 " failed: %s", sportdesc, dportdesc, err);
+                   } else {
+                       logeventf(ssh, "Local port %s forwarding to %s",
+                                 sportdesc, dportdesc);
+                   }
+                   sfree(dportdesc);
+               } else if (type == 'D') {
+                   const char *err = pfd_addforward(NULL, -1,
+                                                    *saddr ? saddr : NULL,
+                                                    sport, ssh, &ssh->cfg);
+                   if (err) {
+                       logeventf(ssh, "Local port %s SOCKS dynamic forward"
+                                 " setup failed: %s", sportdesc, err);
+                   } else {
+                       logeventf(ssh, "Local port %s doing SOCKS"
+                                 " dynamic forwarding", sportdesc);
+                   }
                } else {
                    struct ssh_rportfwd *pf;
                    pf = snew(struct ssh_rportfwd);
@@ -5282,47 +5914,33 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                  " to %s:%d", host, dport);
                        sfree(pf);
                    } else {
-                       logeventf(ssh, "Requesting remote port "
-                                 "%.*s%.*s%.*s%.*s%d%.*s"
+                       logeventf(ssh, "Requesting remote port %s"
                                  " forward to %s:%.*s%.*s%d%.*s",
-                                 (int)(*saddr?strlen(saddr):0),
-                                 *saddr?saddr:NULL,
-                                 (int)(*saddr?1:0), ":",
-                                 (int)(sserv ? strlen(sports) : 0), sports,
-                                 sserv, "(", sport, sserv, ")",
+                                 sportdesc,
                                  host,
                                  (int)(dserv ? strlen(dports) : 0), dports,
                                  dserv, "(", dport, dserv, ")");
-                       ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
-                       ssh2_pkt_addstring(ssh, "tcpip-forward");
-                       ssh2_pkt_addbool(ssh, 1);/* want reply */
-                       if (*saddr)
-                           ssh2_pkt_addstring(ssh, saddr);
-                       if (ssh->cfg.rport_acceptall)
-                           ssh2_pkt_addstring(ssh, "0.0.0.0");
-                       else
-                           ssh2_pkt_addstring(ssh, "127.0.0.1");
-                       ssh2_pkt_adduint32(ssh, sport);
-                       ssh2_pkt_send(ssh);
+                       s->pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
+                       ssh2_pkt_addstring(s->pktout, "tcpip-forward");
+                       ssh2_pkt_addbool(s->pktout, 1);/* want reply */
+                       if (*saddr) {
+                           ssh2_pkt_addstring(s->pktout, saddr);
+                       } else if (ssh->cfg.rport_acceptall) {
+                           ssh2_pkt_addstring(s->pktout, "0.0.0.0");
+                       } else {
+                           ssh2_pkt_addstring(s->pktout, "127.0.0.1");
+                       }
+                       ssh2_pkt_adduint32(s->pktout, sport);
+                       ssh2_pkt_send(ssh, s->pktout);
 
-                       do {
-                           crWaitUntilV(ispkt);
-                           if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
-                               unsigned i = ssh2_pkt_getuint32(ssh);
-                               struct ssh_channel *c;
-                               c = find234(ssh->channels, &i, ssh_channelfind);
-                               if (!c)
-                                   continue;/* nonexistent channel */
-                               c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
-                           }
-                       } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
+                       crWaitUntilV(pktin);
 
-                       if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
-                           if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
-                               bombout((ssh,"Unexpected response to port "
+                       if (pktin->type != SSH2_MSG_REQUEST_SUCCESS) {
+                           if (pktin->type != SSH2_MSG_REQUEST_FAILURE) {
+                               bombout(("Unexpected response to port "
                                         "forwarding request: packet type %d",
-                                        ssh->pktin.type));
-                               crReturnV;
+                                        pktin->type));
+                               crStopV;
                            }
                            logevent("Server refused this port forwarding");
                        } else {
@@ -5330,6 +5948,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                        }
                    }
                }
+               sfree(sportdesc);
            }
        }
     }
@@ -5337,31 +5956,21 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Potentially enable agent forwarding.
      */
-    if (ssh->cfg.agentfwd && agent_exists()) {
+    if (ssh->mainchan && ssh->cfg.agentfwd && agent_exists()) {
        logevent("Requesting OpenSSH-style agent forwarding");
-       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
-       ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
-       ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
-       ssh2_pkt_addbool(ssh, 1);              /* want reply */
-       ssh2_pkt_send(ssh);
-
-       do {
-           crWaitUntilV(ispkt);
-           if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
-               struct ssh_channel *c;
-               c = find234(ssh->channels, &i, ssh_channelfind);
-               if (!c)
-                   continue;          /* nonexistent channel */
-               c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
-           }
-       } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
-
-       if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
-           if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
-               bombout((ssh,"Unexpected response to agent forwarding request:"
-                        " packet type %d", ssh->pktin.type));
-               crReturnV;
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
+       ssh2_pkt_addstring(s->pktout, "auth-agent-req@openssh.com");
+       ssh2_pkt_addbool(s->pktout, 1);        /* want reply */
+       ssh2_pkt_send(ssh, s->pktout);
+
+       crWaitUntilV(pktin);
+
+       if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
+           if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
+               bombout(("Unexpected response to agent forwarding request:"
+                        " packet type %d", pktin->type));
+               crStopV;
            }
            logevent("Agent forwarding refused");
        } else {
@@ -5373,54 +5982,120 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Now allocate a pty for the session.
      */
-    if (!ssh->cfg.nopty) {
-       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
-       ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);       /* recipient channel */
-       ssh2_pkt_addstring(ssh, "pty-req");
-       ssh2_pkt_addbool(ssh, 1);              /* want reply */
-       ssh2_pkt_addstring(ssh, ssh->cfg.termtype);
-       ssh2_pkt_adduint32(ssh, ssh->term_width);
-       ssh2_pkt_adduint32(ssh, ssh->term_height);
-       ssh2_pkt_adduint32(ssh, 0);            /* pixel width */
-       ssh2_pkt_adduint32(ssh, 0);            /* pixel height */
-       ssh2_pkt_addstring_start(ssh);
-       ssh2_pkt_addstring_data(ssh, "\0", 1);  /* TTY_OP_END, no special options */
-       ssh2_pkt_send(ssh);
+    if (ssh->mainchan && !ssh->cfg.nopty) {
+       /* Unpick the terminal-speed string. */
+       /* XXX perhaps we should allow no speeds to be sent. */
+        ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
+       sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
+       /* Build the pty request. */
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); /* recipient channel */
+       ssh2_pkt_addstring(s->pktout, "pty-req");
+       ssh2_pkt_addbool(s->pktout, 1);        /* want reply */
+       ssh2_pkt_addstring(s->pktout, ssh->cfg.termtype);
+       ssh2_pkt_adduint32(s->pktout, ssh->term_width);
+       ssh2_pkt_adduint32(s->pktout, ssh->term_height);
+       ssh2_pkt_adduint32(s->pktout, 0);              /* pixel width */
+       ssh2_pkt_adduint32(s->pktout, 0);              /* pixel height */
+       ssh2_pkt_addstring_start(s->pktout);
+       ssh2_pkt_addbyte(s->pktout, 128);              /* TTY_OP_ISPEED */
+       ssh2_pkt_adduint32(s->pktout, ssh->ispeed);
+       ssh2_pkt_addbyte(s->pktout, 129);              /* TTY_OP_OSPEED */
+       ssh2_pkt_adduint32(s->pktout, ssh->ospeed);
+       ssh2_pkt_addstring_data(s->pktout, "\0", 1); /* TTY_OP_END */
+       ssh2_pkt_send(ssh, s->pktout);
        ssh->state = SSH_STATE_INTERMED;
 
-       do {
-           crWaitUntilV(ispkt);
-           if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
-               struct ssh_channel *c;
-               c = find234(ssh->channels, &i, ssh_channelfind);
-               if (!c)
-                   continue;          /* nonexistent channel */
-               c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
-           }
-       } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
+       crWaitUntilV(pktin);
 
-       if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
-           if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
-               bombout((ssh,"Unexpected response to pty request:"
-                        " packet type %d", ssh->pktin.type));
-               crReturnV;
+       if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
+           if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
+               bombout(("Unexpected response to pty request:"
+                        " packet type %d", pktin->type));
+               crStopV;
            }
            c_write_str(ssh, "Server refused to allocate pty\r\n");
            ssh->editing = ssh->echoing = 1;
        } else {
-           logevent("Allocated pty");
+           logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
+                     ssh->ospeed, ssh->ispeed);
        }
     } else {
        ssh->editing = ssh->echoing = 1;
     }
 
     /*
+     * Send environment variables.
+     * 
+     * Simplest thing here is to send all the requests at once, and
+     * then wait for a whole bunch of successes or failures.
+     */
+    if (ssh->mainchan && *ssh->cfg.environmt) {
+       char *e = ssh->cfg.environmt;
+       char *var, *varend, *val;
+
+       s->num_env = 0;
+
+       while (*e) {
+           var = e;
+           while (*e && *e != '\t') e++;
+           varend = e;
+           if (*e == '\t') e++;
+           val = e;
+           while (*e) e++;
+           e++;
+
+           s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+           ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
+           ssh2_pkt_addstring(s->pktout, "env");
+           ssh2_pkt_addbool(s->pktout, 1);            /* want reply */
+           ssh2_pkt_addstring_start(s->pktout);
+           ssh2_pkt_addstring_data(s->pktout, var, varend-var);
+           ssh2_pkt_addstring(s->pktout, val);
+           ssh2_pkt_send(ssh, s->pktout);
+
+           s->num_env++;
+       }
+
+       logeventf(ssh, "Sent %d environment variables", s->num_env);
+
+       s->env_ok = 0;
+       s->env_left = s->num_env;
+
+       while (s->env_left > 0) {
+           crWaitUntilV(pktin);
+
+           if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
+               if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
+                   bombout(("Unexpected response to environment request:"
+                            " packet type %d", pktin->type));
+                   crStopV;
+               }
+           } else {
+               s->env_ok++;
+           }
+
+           s->env_left--;
+       }
+
+       if (s->env_ok == s->num_env) {
+           logevent("All environment variables successfully set");
+       } else if (s->env_ok == 0) {
+           logevent("All environment variables refused");
+           c_write_str(ssh, "Server refused to set environment variables\r\n");
+       } else {
+           logeventf(ssh, "%d environment variables refused",
+                     s->num_env - s->env_ok);
+           c_write_str(ssh, "Server refused to set all environment variables\r\n");
+       }
+    }
+
+    /*
      * Start a shell or a remote command. We may have to attempt
      * this twice if the config data has provided a second choice
      * of command.
      */
-    while (1) {
+    if (ssh->mainchan) while (1) {
        int subsys;
        char *cmd;
 
@@ -5432,37 +6107,29 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
            cmd = ssh->cfg.remote_cmd_ptr;
        }
 
-       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
-       ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);       /* recipient channel */
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); /* recipient channel */
        if (subsys) {
-           ssh2_pkt_addstring(ssh, "subsystem");
-           ssh2_pkt_addbool(ssh, 1);          /* want reply */
-           ssh2_pkt_addstring(ssh, cmd);
+           ssh2_pkt_addstring(s->pktout, "subsystem");
+           ssh2_pkt_addbool(s->pktout, 1);            /* want reply */
+           ssh2_pkt_addstring(s->pktout, cmd);
        } else if (*cmd) {
-           ssh2_pkt_addstring(ssh, "exec");
-           ssh2_pkt_addbool(ssh, 1);          /* want reply */
-           ssh2_pkt_addstring(ssh, cmd);
+           ssh2_pkt_addstring(s->pktout, "exec");
+           ssh2_pkt_addbool(s->pktout, 1);            /* want reply */
+           ssh2_pkt_addstring(s->pktout, cmd);
        } else {
-           ssh2_pkt_addstring(ssh, "shell");
-           ssh2_pkt_addbool(ssh, 1);          /* want reply */
+           ssh2_pkt_addstring(s->pktout, "shell");
+           ssh2_pkt_addbool(s->pktout, 1);            /* want reply */
        }
-       ssh2_pkt_send(ssh);
-       do {
-           crWaitUntilV(ispkt);
-           if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
-               struct ssh_channel *c;
-               c = find234(ssh->channels, &i, ssh_channelfind);
-               if (!c)
-                   continue;          /* nonexistent channel */
-               c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
-           }
-       } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
-       if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
-           if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
-               bombout((ssh,"Unexpected response to shell/command request:"
-                        " packet type %d", ssh->pktin.type));
-               crReturnV;
+       ssh2_pkt_send(ssh, s->pktout);
+
+       crWaitUntilV(pktin);
+
+       if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
+           if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
+               bombout(("Unexpected response to shell/command request:"
+                        " packet type %d", pktin->type));
+               crStopV;
            }
            /*
             * We failed to start the command. If this is the
@@ -5475,8 +6142,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                ssh->fallback_cmd = TRUE;
                continue;
            }
-           bombout((ssh,"Server refused to start a shell/command"));
-           crReturnV;
+           bombout(("Server refused to start a shell/command"));
+           crStopV;
        } else {
            logevent("Started a shell/command");
        }
@@ -5494,31 +6161,32 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
      */
     if (ssh->ldisc)
        ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
-    ssh->send_ok = 1;
+    if (ssh->mainchan)
+       ssh->send_ok = 1;
     while (1) {
        crReturnV;
        s->try_send = FALSE;
-       if (ispkt) {
-           if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
-               ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
+       if (pktin) {
+           if (pktin->type == SSH2_MSG_CHANNEL_DATA ||
+               pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
                char *data;
                int length;
-               unsigned i = ssh2_pkt_getuint32(ssh);
+               unsigned i = ssh_pkt_getuint32(pktin);
                struct ssh_channel *c;
                c = find234(ssh->channels, &i, ssh_channelfind);
                if (!c)
                    continue;          /* nonexistent channel */
-               if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
-                   ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
+               if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
+                   ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
                    continue;          /* extended but not stderr */
-               ssh2_pkt_getstring(ssh, &data, &length);
+               ssh_pkt_getstring(pktin, &data, &length);
                if (data) {
-                   int bufsize;
+                   int bufsize = 0;
                    c->v.v2.locwindow -= length;
                    switch (c->type) {
                      case CHAN_MAINSESSION:
                        bufsize =
-                           from_backend(ssh->frontend, ssh->pktin.type ==
+                           from_backend(ssh->frontend, pktin->type ==
                                         SSH2_MSG_CHANNEL_EXTENDED_DATA,
                                         data, length);
                        break;
@@ -5556,22 +6224,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                                c->u.a.lensofar += l;
                            }
                            if (c->u.a.lensofar == c->u.a.totallen) {
-                               void *reply, *sentreply;
+                               void *reply;
                                int replylen;
-                               agent_query(c->u.a.message,
-                                           c->u.a.totallen, &reply,
-                                           &replylen);
-                               if (reply)
-                                   sentreply = reply;
-                               else {
-                                   /* Fake SSH_AGENT_FAILURE. */
-                                   sentreply = "\0\0\0\1\5";
-                                   replylen = 5;
-                               }
-                               ssh2_add_channel_data(c, sentreply, replylen);
-                               s->try_send = TRUE;
-                               if (reply)
-                                   sfree(reply);
+                               if (agent_query(c->u.a.message,
+                                               c->u.a.totallen,
+                                               &reply, &replylen,
+                                               ssh_agentf_callback, c))
+                                   ssh_agentf_callback(c, reply, replylen);
                                sfree(c->u.a.message);
                                c->u.a.lensofar = 0;
                            }
@@ -5586,8 +6245,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    if (bufsize < OUR_V2_WINSIZE)
                        ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
                }
-           } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
+           } else if (pktin->type == SSH2_MSG_CHANNEL_EOF) {
+               unsigned i = ssh_pkt_getuint32(pktin);
                struct ssh_channel *c;
 
                c = find234(ssh->channels, &i, ssh_channelfind);
@@ -5607,19 +6266,22 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    pfd_close(c->u.pfd.s);
                    sshfwd_close(c);
                }
-           } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
+           } else if (pktin->type == SSH2_MSG_CHANNEL_CLOSE) {
+               unsigned i = ssh_pkt_getuint32(pktin);
                struct ssh_channel *c;
 
                c = find234(ssh->channels, &i, ssh_channelfind);
                if (!c || ((int)c->remoteid) == -1) {
-                   bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
+                   bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
                             c ? "half-open" : "nonexistent", i));
+                   crStopV;
                }
                /* Do pre-close processing on the channel. */
                switch (c->type) {
                  case CHAN_MAINSESSION:
-                   break;             /* nothing to see here, move along */
+                   ssh->mainchan = NULL;
+                   update_specials_menu(ssh->frontend);
+                   break;
                  case CHAN_X11:
                    if (c->u.x11.s != NULL)
                        x11_close(c->u.x11.s);
@@ -5635,9 +6297,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    break;
                }
                if (c->closes == 0) {
-                   ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
-                   ssh2_pkt_adduint32(ssh, c->remoteid);
-                   ssh2_pkt_send(ssh);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
+                   ssh2_pkt_adduint32(s->pktout, c->remoteid);
+                   ssh2_pkt_send(ssh, s->pktout);
                }
                del234(ssh->channels, c);
                bufchain_clear(&c->v.v2.outbuffer);
@@ -5645,8 +6307,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
                /*
                 * See if that was the last channel left open.
+                * (This is only our termination condition if we're
+                * not running in -N mode.)
                 */
-               if (count234(ssh->channels) == 0) {
+               if (!ssh->cfg.ssh_no_shell && count234(ssh->channels) == 0) {
+                   logevent("All channels closed. Disconnecting");
 #if 0
                     /*
                      * We used to send SSH_MSG_DISCONNECT here,
@@ -5659,37 +6324,28 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                      * this is more polite than sending a
                      * DISCONNECT. So now we don't.
                      */
-                   logevent("All channels closed. Disconnecting");
-                   ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
-                   ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
-                   ssh2_pkt_addstring(ssh, "All open channels closed");
-                   ssh2_pkt_addstring(ssh, "en");      /* language tag */
-                   ssh2_pkt_send(ssh);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
+                   ssh2_pkt_adduint32(s->pktout, SSH2_DISCONNECT_BY_APPLICATION);
+                   ssh2_pkt_addstring(s->pktout, "All open channels closed");
+                   ssh2_pkt_addstring(s->pktout, "en");        /* language tag */
+                   ssh2_pkt_send_noqueue(ssh, s->pktout);
 #endif
-                   ssh->state = SSH_STATE_CLOSED;
-                   crReturnV;
+                    ssh_closing((Plug)ssh, NULL, 0, 0);
+                   crStopV;
                }
                continue;              /* remote sends close; ignore (FIXME) */
-           } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
-               struct ssh_channel *c;
-               c = find234(ssh->channels, &i, ssh_channelfind);
-               if (!c || c->closes)
-                   continue;          /* nonexistent or closing channel */
-               c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
-               s->try_send = TRUE;
-           } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
+           } else if (pktin->type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
+               unsigned i = ssh_pkt_getuint32(pktin);
                struct ssh_channel *c;
                c = find234(ssh->channels, &i, ssh_channelfind);
                if (!c)
                    continue;          /* nonexistent channel */
                if (c->type != CHAN_SOCKDATA_DORMANT)
                    continue;          /* dunno why they're confirming this */
-               c->remoteid = ssh2_pkt_getuint32(ssh);
+               c->remoteid = ssh_pkt_getuint32(pktin);
                c->type = CHAN_SOCKDATA;
-               c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
-               c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
+               c->v.v2.remwindow = ssh_pkt_getuint32(pktin);
+               c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin);
                if (c->u.pfd.s)
                    pfd_confirm(c->u.pfd.s);
                if (c->closes) {
@@ -5699,12 +6355,23 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * the channel open. So now we know the
                     * remoteid, we can close it again.
                     */
-                   ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
-                   ssh2_pkt_adduint32(ssh, c->remoteid);
-                   ssh2_pkt_send(ssh);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
+                   ssh2_pkt_adduint32(s->pktout, c->remoteid);
+                   ssh2_pkt_send(ssh, s->pktout);
                }
-           } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
-               unsigned i = ssh2_pkt_getuint32(ssh);
+           } else if (pktin->type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
+                static const char *const reasons[] = {
+                    "<unknown reason code>",
+                    "Administratively prohibited",
+                    "Connect failed",
+                    "Unknown channel type",
+                    "Resource shortage",
+                };
+               unsigned i = ssh_pkt_getuint32(pktin);
+                unsigned reason_code;
+                char *reason_string;
+                int reason_length;
+                char *message;
                struct ssh_channel *c;
                c = find234(ssh->channels, &i, ssh_channelfind);
                if (!c)
@@ -5712,21 +6379,30 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                if (c->type != CHAN_SOCKDATA_DORMANT)
                    continue;          /* dunno why they're failing this */
 
-               logevent("Forwarded connection refused by server");
+                reason_code = ssh_pkt_getuint32(pktin);
+                if (reason_code >= lenof(reasons))
+                    reason_code = 0; /* ensure reasons[reason_code] in range */
+                ssh_pkt_getstring(pktin, &reason_string, &reason_length);
+                message = dupprintf("Forwarded connection refused by"
+                                    " server: %s [%.*s]", reasons[reason_code],
+                                    reason_length, reason_string);
+               logevent(message);
+                sfree(message);
 
                pfd_close(c->u.pfd.s);
 
                del234(ssh->channels, c);
                sfree(c);
-           } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
+           } else if (pktin->type == SSH2_MSG_CHANNEL_REQUEST) {
                unsigned localid;
                char *type;
                int typelen, want_reply;
+               int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
                struct ssh_channel *c;
 
-               localid = ssh2_pkt_getuint32(ssh);
-               ssh2_pkt_getstring(ssh, &type, &typelen);
-               want_reply = ssh2_pkt_getbool(ssh);
+               localid = ssh_pkt_getuint32(pktin);
+               ssh_pkt_getstring(pktin, &type, &typelen);
+               want_reply = ssh2_pkt_getbool(pktin);
 
                /*
                 * First, check that the channel exists. Otherwise,
@@ -5738,14 +6414,14 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    sprintf(buf, "Received channel request for nonexistent"
                            " channel %d", localid);
                    logevent(buf);
-                   ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
-                   ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
-                   ssh2_pkt_addstring(ssh, buf);
-                   ssh2_pkt_addstring(ssh, "en");      /* language tag */
-                   ssh2_pkt_send(ssh);
-                   connection_fatal("%s", buf);
-                   ssh->state = SSH_STATE_CLOSED;
-                   crReturnV;
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT);
+                   ssh2_pkt_adduint32(s->pktout, SSH2_DISCONNECT_BY_APPLICATION);
+                   ssh2_pkt_addstring(s->pktout, buf);
+                   ssh2_pkt_addstring(s->pktout, "en");        /* language tag */
+                   ssh2_pkt_send_noqueue(ssh, s->pktout);
+                   connection_fatal(ssh->frontend, "%s", buf);
+                    ssh_closing((Plug)ssh, NULL, 0, 0);
+                   crStopV;
                }
 
                /*
@@ -5753,18 +6429,94 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 * the request type string to see if it's something
                 * we recognise.
                 */
-               if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
-                   c == ssh->mainchan) {
-                   /* We recognise "exit-status" on the primary channel. */
-                   char buf[100];
-                   ssh->exitcode = ssh2_pkt_getuint32(ssh);
-                   sprintf(buf, "Server sent command exit status %d",
-                           ssh->exitcode);
-                   logevent(buf);
-                   if (want_reply) {
-                       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
-                       ssh2_pkt_adduint32(ssh, c->remoteid);
-                       ssh2_pkt_send(ssh);
+               if (c == ssh->mainchan) {
+                   /*
+                    * We recognise "exit-status" and "exit-signal" on
+                    * the primary channel.
+                    */
+                   if (typelen == 11 &&
+                       !memcmp(type, "exit-status", 11)) {
+
+                       ssh->exitcode = ssh_pkt_getuint32(pktin);
+                       logeventf(ssh, "Server sent command exit status %d",
+                                 ssh->exitcode);
+                       reply = SSH2_MSG_CHANNEL_SUCCESS;
+
+                   } else if (typelen == 11 &&
+                              !memcmp(type, "exit-signal", 11)) {
+
+                       int is_plausible = TRUE, is_int = FALSE;
+                       char *fmt_sig = "", *fmt_msg = "";
+                       char *msg;
+                       int msglen = 0, core = FALSE;
+                       /* ICK: older versions of OpenSSH (e.g. 3.4p1)
+                        * provide an `int' for the signal, despite its
+                        * having been a `string' in the drafts since at
+                        * least 2001. (Fixed in session.c 1.147.) Try to
+                        * infer which we can safely parse it as. */
+                       {
+                           unsigned char *p = pktin->body +
+                                              pktin->savedpos;
+                           long len = pktin->length - pktin->savedpos;
+                           unsigned long num = GET_32BIT(p); /* what is it? */
+                           /* If it's 0, it hardly matters; assume string */
+                           if (num == 0) {
+                               is_int = FALSE;
+                           } else {
+                               int maybe_int = FALSE, maybe_str = FALSE;
+#define CHECK_HYPOTHESIS(offset, result) \
+    do { \
+       long q = offset; \
+       if (q >= 0 && q+4 <= len) { \
+           q = q + 4 + GET_32BIT(p+q); \
+           if (q >= 0 && q+4 <= len && \
+                   (q = q + 4 + GET_32BIT(p+q)) && q == len) \
+               result = TRUE; \
+       } \
+    } while(0)
+                               CHECK_HYPOTHESIS(4+1, maybe_int);
+                               CHECK_HYPOTHESIS(4+num+1, maybe_str);
+#undef CHECK_HYPOTHESIS
+                               if (maybe_int && !maybe_str)
+                                   is_int = TRUE;
+                               else if (!maybe_int && maybe_str)
+                                   is_int = FALSE;
+                               else
+                                   /* Crikey. Either or neither. Panic. */
+                                   is_plausible = FALSE;
+                           }
+                       }
+                       if (is_plausible) {
+                           if (is_int) {
+                               /* Old non-standard OpenSSH. */
+                               int signum = ssh_pkt_getuint32(pktin);
+                               fmt_sig = dupprintf(" %d", signum);
+                           } else {
+                               /* As per the drafts. */
+                               char *sig;
+                               int siglen;
+                               ssh_pkt_getstring(pktin, &sig, &siglen);
+                               /* Signal name isn't supposed to be blank, but
+                                * let's cope gracefully if it is. */
+                               if (siglen) {
+                                   fmt_sig = dupprintf(" \"%.*s\"",
+                                                       siglen, sig);
+                               }
+                           }
+                           core = ssh2_pkt_getbool(pktin);
+                           ssh_pkt_getstring(pktin, &msg, &msglen);
+                           if (msglen) {
+                               fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg);
+                           }
+                           /* ignore lang tag */
+                       } /* else don't attempt to parse */
+                       logeventf(ssh, "Server exited on signal%s%s%s",
+                                 fmt_sig, core ? " (core dumped)" : "",
+                                 fmt_msg);
+                       if (*fmt_sig) sfree(fmt_sig);
+                       if (*fmt_msg) sfree(fmt_msg);
+                       reply = SSH2_MSG_CHANNEL_SUCCESS;
+
                    }
                } else {
                    /*
@@ -5773,18 +6525,19 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                     * or respond with CHANNEL_FAILURE, depending
                     * on want_reply.
                     */
-                   if (want_reply) {
-                       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
-                       ssh2_pkt_adduint32(ssh, c->remoteid);
-                       ssh2_pkt_send(ssh);
-                   }
+                   reply = SSH2_MSG_CHANNEL_FAILURE;
                }
-           } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
+               if (want_reply) {
+                   s->pktout = ssh2_pkt_init(reply);
+                   ssh2_pkt_adduint32(s->pktout, c->remoteid);
+                   ssh2_pkt_send(ssh, s->pktout);
+               }
+           } else if (pktin->type == SSH2_MSG_GLOBAL_REQUEST) {
                char *type;
                int typelen, want_reply;
 
-               ssh2_pkt_getstring(ssh, &type, &typelen);
-               want_reply = ssh2_pkt_getbool(ssh);
+               ssh_pkt_getstring(pktin, &type, &typelen);
+               want_reply = ssh2_pkt_getbool(pktin);
 
                 /*
                  * We currently don't support any global requests
@@ -5793,40 +6546,46 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                  * want_reply.
                  */
                 if (want_reply) {
-                    ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
-                    ssh2_pkt_send(ssh);
+                    s->pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE);
+                    ssh2_pkt_send(ssh, s->pktout);
                }
-           } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
+           } else if (pktin->type == SSH2_MSG_CHANNEL_OPEN) {
                char *type;
                int typelen;
                char *peeraddr;
                int peeraddrlen;
-               int port;
+               int peerport;
                char *error = NULL;
                struct ssh_channel *c;
                unsigned remid, winsize, pktsize;
-               ssh2_pkt_getstring(ssh, &type, &typelen);
+               ssh_pkt_getstring(pktin, &type, &typelen);
                c = snew(struct ssh_channel);
                c->ssh = ssh;
 
-               remid = ssh2_pkt_getuint32(ssh);
-               winsize = ssh2_pkt_getuint32(ssh);
-               pktsize = ssh2_pkt_getuint32(ssh);
-               ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
-               port = ssh2_pkt_getuint32(ssh);
+               remid = ssh_pkt_getuint32(pktin);
+               winsize = ssh_pkt_getuint32(pktin);
+               pktsize = ssh_pkt_getuint32(pktin);
 
                if (typelen == 3 && !memcmp(type, "x11", 3)) {
-                   char *addrstr = snewn(peeraddrlen+1, char);
+                   char *addrstr;
+
+                    ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
+                   addrstr = snewn(peeraddrlen+1, char);
                    memcpy(addrstr, peeraddr, peeraddrlen);
-                   peeraddr[peeraddrlen] = '\0';
+                   addrstr[peeraddrlen] = '\0';
+                    peerport = ssh_pkt_getuint32(pktin);
+
+                   logeventf(ssh, "Received X11 connect request from %s:%d",
+                             addrstr, peerport);
 
                    if (!ssh->X11_fwd_enabled)
                        error = "X11 forwarding is not enabled";
                    else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
-                                     ssh->x11auth, addrstr, port,
+                                     ssh->x11auth, addrstr, peerport,
                                      &ssh->cfg) != NULL) {
                        error = "Unable to open an X11 connection";
                    } else {
+                       logevent("Opening X11 forward connection succeeded");
                        c->type = CHAN_X11;
                    }
 
@@ -5836,16 +6595,22 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    struct ssh_rportfwd pf, *realpf;
                    char *dummy;
                    int dummylen;
-                   ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
-                   pf.sport = ssh2_pkt_getuint32(ssh);
+                   ssh_pkt_getstring(pktin, &dummy, &dummylen);/* skip address */
+                   pf.sport = ssh_pkt_getuint32(pktin);
+                    ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
+                    peerport = ssh_pkt_getuint32(pktin);
                    realpf = find234(ssh->rportfwds, &pf, NULL);
+                   logeventf(ssh, "Received remote port %d open request "
+                             "from %s:%d", pf.sport, peeraddr, peerport);
                    if (realpf == NULL) {
                        error = "Remote port is not recognised";
                    } else {
-                       char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
-                                                realpf->dport, c, &ssh->cfg);
-                       logeventf(ssh, "Received remote port open request"
-                                 " for %s:%d", realpf->dhost, realpf->dport);
+                       const char *e = pfd_newconnect(&c->u.pfd.s,
+                                                      realpf->dhost,
+                                                      realpf->dport, c,
+                                                      &ssh->cfg);
+                       logeventf(ssh, "Attempting to forward remote port to "
+                                 "%s:%d", realpf->dhost, realpf->dport);
                        if (e != NULL) {
                            logeventf(ssh, "Port open failed: %s", e);
                            error = "Port open failed";
@@ -5868,12 +6633,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
                c->remoteid = remid;
                if (error) {
-                   ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
-                   ssh2_pkt_adduint32(ssh, c->remoteid);
-                   ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
-                   ssh2_pkt_addstring(ssh, error);
-                   ssh2_pkt_addstring(ssh, "en");      /* language tag */
-                   ssh2_pkt_send(ssh);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
+                   ssh2_pkt_adduint32(s->pktout, c->remoteid);
+                   ssh2_pkt_adduint32(s->pktout, SSH2_OPEN_CONNECT_FAILED);
+                   ssh2_pkt_addstring(s->pktout, error);
+                   ssh2_pkt_addstring(s->pktout, "en");        /* language tag */
+                   ssh2_pkt_send(ssh, s->pktout);
+                   logeventf(ssh, "Rejected channel open: %s", error);
                    sfree(c);
                } else {
                    c->localid = alloc_channel_id(ssh);
@@ -5883,18 +6649,18 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                    c->v.v2.remmaxpkt = pktsize;
                    bufchain_init(&c->v.v2.outbuffer);
                    add234(ssh->channels, c);
-                   ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
-                   ssh2_pkt_adduint32(ssh, c->remoteid);
-                   ssh2_pkt_adduint32(ssh, c->localid);
-                   ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
-                   ssh2_pkt_adduint32(ssh, 0x4000UL);  /* our max pkt size */
-                   ssh2_pkt_send(ssh);
+                   s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
+                   ssh2_pkt_adduint32(s->pktout, c->remoteid);
+                   ssh2_pkt_adduint32(s->pktout, c->localid);
+                   ssh2_pkt_adduint32(s->pktout, c->v.v2.locwindow);
+                   ssh2_pkt_adduint32(s->pktout, 0x4000UL);    /* our max pkt size */
+                   ssh2_pkt_send(ssh, s->pktout);
                }
            } else {
-               bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
-               crReturnV;
+               bombout(("Strange packet received: type %d", pktin->type));
+               crStopV;
            }
-       } else {
+       } else if (ssh->mainchan) {
            /*
             * We have spare data. Add it to the channel buffer.
             */
@@ -5938,13 +6704,148 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 }
 
 /*
+ * Handlers for SSH2 messages that might arrive at any moment.
+ */
+void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
+{
+    /* log reason code in disconnect message */
+    char *buf, *msg;
+    int nowlen, reason, msglen;
+
+    reason = ssh_pkt_getuint32(pktin);
+    ssh_pkt_getstring(pktin, &msg, &msglen);
+
+    if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
+       buf = dupprintf("Received disconnect message (%s)",
+                       ssh2_disconnect_reasons[reason]);
+    } else {
+       buf = dupprintf("Received disconnect message (unknown"
+                       " type %d)", reason);
+    }
+    logevent(buf);
+    sfree(buf);
+    buf = dupprintf("Disconnection message text: %n%.*s",
+                   &nowlen, msglen, msg);
+    logevent(buf);
+    bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
+            reason,
+            (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
+            ssh2_disconnect_reasons[reason] : "unknown",
+            buf+nowlen));
+    sfree(buf);
+}
+
+void ssh2_msg_debug(Ssh ssh, struct Packet *pktin)
+{
+    /* log the debug message */
+    char *buf, *msg;
+    int msglen;
+    int always_display;
+
+    /* XXX maybe we should actually take notice of this */
+    always_display = ssh2_pkt_getbool(pktin);
+    ssh_pkt_getstring(pktin, &msg, &msglen);
+
+    buf = dupprintf("Remote debug message: %.*s", msglen, msg);
+    logevent(buf);
+    sfree(buf);
+}
+
+void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin)
+{
+    struct Packet *pktout;
+    pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED);
+    ssh2_pkt_adduint32(pktout, pktin->sequence);
+    /*
+     * UNIMPLEMENTED messages MUST appear in the same order as the
+     * messages they respond to. Hence, never queue them.
+     */
+    ssh2_pkt_send_noqueue(ssh, pktout);
+}
+
+/*
  * Handle the top-level SSH2 protocol.
  */
-static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
+static void ssh2_protocol_setup(Ssh ssh)
 {
-    if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
+    int i;
+
+    /*
+     * Most messages cause SSH2_MSG_UNIMPLEMENTED.
+     */
+    for (i = 0; i < 256; i++)
+       ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented;
+
+    /*
+     * Any message we actually understand, we set to NULL so that
+     * the coroutines will get it.
+     */
+    ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_KEXINIT] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = NULL;
+    /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = NULL; duplicate case value */
+    /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = NULL; duplicate case value */
+    ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = NULL;
+    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = NULL; duplicate case value */
+    /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = NULL; duplicate case value */
+    ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = NULL;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = NULL;
+
+    /*
+     * These special message types we install handlers for.
+     */
+    ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect;
+    ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with ssh1 */
+    ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug;
+}
+
+static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen,
+                         struct Packet *pktin)
+{
+    if (ssh->state == SSH_STATE_CLOSED)
        return;
-    do_ssh2_authconn(ssh, in, inlen, ispkt);
+
+    if (pktin && ssh->packet_dispatch[pktin->type]) {
+       ssh->packet_dispatch[pktin->type](ssh, pktin);
+       return;
+    }
+
+    if (!ssh->protocol_initial_phase_done ||
+       (pktin && pktin->type >= 20 && pktin->type < 50)) {
+       if (do_ssh2_transport(ssh, in, inlen, pktin) &&
+           !ssh->protocol_initial_phase_done) {
+           ssh->protocol_initial_phase_done = TRUE;
+           /*
+            * Allow authconn to initialise itself.
+            */
+           do_ssh2_authconn(ssh, NULL, 0, NULL);
+       }
+    } else {
+       do_ssh2_authconn(ssh, in, inlen, pktin);
+    }
 }
 
 /*
@@ -5952,15 +6853,17 @@ static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
  *
  * Returns an error message, or NULL on success.
  */
-static char *ssh_init(void *frontend_handle, void **backend_handle,
-                     Config *cfg,
-                     char *host, int port, char **realhost, int nodelay)
+static const char *ssh_init(void *frontend_handle, void **backend_handle,
+                           Config *cfg,
+                           char *host, int port, char **realhost, int nodelay,
+                           int keepalive)
 {
-    char *p;
+    const char *p;
     Ssh ssh;
 
     ssh = snew(struct ssh_tag);
     ssh->cfg = *cfg;                  /* STRUCTURE COPY */
+    ssh->version = 0;                 /* when not ready yet */
     ssh->s = NULL;
     ssh->cipher = NULL;
     ssh->v1_cipher_ctx = NULL;
@@ -5986,10 +6889,6 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->eof_needed = FALSE;
     ssh->ldisc = NULL;
     ssh->logctx = NULL;
-    {
-       static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
-       ssh->pktin = ssh->pktout = empty;
-    }
     ssh->deferred_send_data = NULL;
     ssh->deferred_len = 0;
     ssh->deferred_size = 0;
@@ -6002,7 +6901,7 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->ssh2_rdpkt_crstate = 0;
     ssh->do_ssh_init_crstate = 0;
     ssh->ssh_gotdata_crstate = 0;
-    ssh->ssh1_protocol_crstate = 0;
+    ssh->do_ssh1_connection_crstate = 0;
     ssh->do_ssh1_login_crstate = 0;
     ssh->do_ssh2_transport_crstate = 0;
     ssh->do_ssh2_authconn_crstate = 0;
@@ -6013,6 +6912,9 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->mainchan = NULL;
     ssh->throttled_all = 0;
     ssh->v1_stdout_throttling = 0;
+    ssh->queue = NULL;
+    ssh->queuelen = ssh->queuesize = 0;
+    ssh->queueing = FALSE;
 
     *backend_handle = ssh;
 
@@ -6037,7 +6939,11 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
 
     ssh->protocol = NULL;
 
-    p = connect_to_host(ssh, host, port, realhost, nodelay);
+    ssh->protocol_initial_phase_done = FALSE;
+
+    ssh->pinger = NULL;
+
+    p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive);
     if (p != NULL)
        return p;
 
@@ -6060,14 +6966,26 @@ static void ssh_free(void *handle)
        ssh->csmac->free_context(ssh->cs_mac_ctx);
     if (ssh->sc_mac_ctx)
        ssh->scmac->free_context(ssh->sc_mac_ctx);
-    if (ssh->cs_comp_ctx)
-       ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
-    if (ssh->sc_comp_ctx)
-       ssh->sccomp->compress_cleanup(ssh->sc_comp_ctx);
+    if (ssh->cs_comp_ctx) {
+       if (ssh->cscomp)
+           ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
+       else
+           zlib_compress_cleanup(ssh->cs_comp_ctx);
+    }
+    if (ssh->sc_comp_ctx) {
+       if (ssh->sccomp)
+           ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
+       else
+           zlib_decompress_cleanup(ssh->sc_comp_ctx);
+    }
     if (ssh->kex_ctx)
        dh_cleanup(ssh->kex_ctx);
     sfree(ssh->savedhost);
 
+    while (ssh->queuelen-- > 0)
+       ssh_free_packet(ssh->queue[ssh->queuelen]);
+    sfree(ssh->queue);
+
     if (ssh->channels) {
        while ((c = delpos234(ssh->channels, 0)) != NULL) {
            switch (c->type) {
@@ -6097,10 +7015,15 @@ static void ssh_free(void *handle)
     sfree(ssh->do_ssh1_login_state);
     sfree(ssh->do_ssh2_transport_state);
     sfree(ssh->do_ssh2_authconn_state);
-    
+    if (ssh->crcda_ctx) {
+       crcda_free_context(ssh->crcda_ctx);
+       ssh->crcda_ctx = NULL;
+    }
     if (ssh->s)
-       sk_close(ssh->s);
+       ssh_do_close(ssh);
     sfree(ssh);
+    if (ssh->pinger)
+       pinger_free(ssh->pinger);
 }
 
 /*
@@ -6115,6 +7038,7 @@ static void ssh_free(void *handle)
 static void ssh_reconfig(void *handle, Config *cfg)
 {
     Ssh ssh = (Ssh) handle;
+    pinger_reconfig(ssh->pinger, &ssh->cfg, cfg);
     ssh->cfg = *cfg;                  /* STRUCTURE COPY */
 }
 
@@ -6171,6 +7095,7 @@ static int ssh_sendbuffer(void *handle)
 static void ssh_size(void *handle, int width, int height)
 {
     Ssh ssh = (Ssh) handle;
+    struct Packet *pktout;
 
     ssh->term_width = width;
     ssh->term_height = height;
@@ -6190,16 +7115,16 @@ static void ssh_size(void *handle, int width, int height)
                            PKT_INT, ssh->term_height,
                            PKT_INT, ssh->term_width,
                            PKT_INT, 0, PKT_INT, 0, PKT_END);
-           } else {
-               ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
-               ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
-               ssh2_pkt_addstring(ssh, "window-change");
-               ssh2_pkt_addbool(ssh, 0);
-               ssh2_pkt_adduint32(ssh, ssh->term_width);
-               ssh2_pkt_adduint32(ssh, ssh->term_height);
-               ssh2_pkt_adduint32(ssh, 0);
-               ssh2_pkt_adduint32(ssh, 0);
-               ssh2_pkt_send(ssh);
+           } else if (ssh->mainchan) {
+               pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+               ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
+               ssh2_pkt_addstring(pktout, "window-change");
+               ssh2_pkt_addbool(pktout, 0);
+               ssh2_pkt_adduint32(pktout, ssh->term_width);
+               ssh2_pkt_adduint32(pktout, ssh->term_height);
+               ssh2_pkt_adduint32(pktout, 0);
+               ssh2_pkt_adduint32(pktout, 0);
+               ssh2_pkt_send(ssh, pktout);
            }
        }
        break;
@@ -6207,6 +7132,70 @@ static void ssh_size(void *handle, int width, int height)
 }
 
 /*
+ * Return a list of the special codes that make sense in this
+ * protocol.
+ */
+static const struct telnet_special *ssh_get_specials(void *handle)
+{
+    static const struct telnet_special ignore_special[] = {
+       {"IGNORE message", TS_NOP},
+    };
+    static const struct telnet_special ssh2_session_specials[] = {
+       {NULL, TS_SEP},
+       {"Break", TS_BRK},
+       /* These are the signal names defined by draft-ietf-secsh-connect-19.
+        * They include all the ISO C signals, but are a subset of the POSIX
+        * required signals. */
+       {"SIGINT (Interrupt)", TS_SIGINT},
+       {"SIGTERM (Terminate)", TS_SIGTERM},
+       {"SIGKILL (Kill)", TS_SIGKILL},
+       {"SIGQUIT (Quit)", TS_SIGQUIT},
+       {"SIGHUP (Hangup)", TS_SIGHUP},
+       {"More signals", TS_SUBMENU},
+         {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM},
+         {"SIGFPE",  TS_SIGFPE},  {"SIGILL",  TS_SIGILL},
+         {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV},
+         {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2},
+       {NULL, TS_EXITMENU}
+    };
+    static const struct telnet_special specials_end[] = {
+       {NULL, TS_EXITMENU}
+    };
+    static struct telnet_special ssh_specials[lenof(ignore_special) +
+                                             lenof(ssh2_session_specials) +
+                                             lenof(specials_end)];
+    Ssh ssh = (Ssh) handle;
+    int i = 0;
+#define ADD_SPECIALS(name) \
+    do { \
+       assert((i + lenof(name)) <= lenof(ssh_specials)); \
+       memcpy(&ssh_specials[i], name, sizeof name); \
+       i += lenof(name); \
+    } while(0)
+
+    if (ssh->version == 1) {
+       /* Don't bother offering IGNORE if we've decided the remote
+        * won't cope with it, since we wouldn't bother sending it if
+        * asked anyway. */
+       if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
+           ADD_SPECIALS(ignore_special);
+    } else if (ssh->version == 2) {
+       /* XXX add rekey, when implemented */
+       ADD_SPECIALS(ignore_special);
+       if (ssh->mainchan)
+           ADD_SPECIALS(ssh2_session_specials);
+    } /* else we're not ready yet */
+
+    if (i) {
+       ADD_SPECIALS(specials_end);
+       return ssh_specials;
+    } else {
+       return NULL;
+    }
+#undef ADD_SPECIALS
+}
+
+/*
  * Send Telnet special codes. TS_EOF is useful for `plink', so you
  * can send an EOF and collect resulting output (e.g. `plink
  * hostname sort').
@@ -6214,6 +7203,7 @@ static void ssh_size(void *handle, int width, int height)
 static void ssh_special(void *handle, Telnet_Special code)
 {
     Ssh ssh = (Ssh) handle;
+    struct Packet *pktout;
 
     if (code == TS_EOF) {
        if (ssh->state != SSH_STATE_SESSION) {
@@ -6227,25 +7217,68 @@ static void ssh_special(void *handle, Telnet_Special code)
        }
        if (ssh->version == 1) {
            send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
-       } else {
-           ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
-           ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
-           ssh2_pkt_send(ssh);
+       } else if (ssh->mainchan) {
+           struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
+           ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
+           ssh2_pkt_send(ssh, pktout);
        }
        logevent("Sent EOF message");
-    } else if (code == TS_PING) {
+    } else if (code == TS_PING || code == TS_NOP) {
        if (ssh->state == SSH_STATE_CLOSED
            || ssh->state == SSH_STATE_PREPACKET) return;
        if (ssh->version == 1) {
            if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
                send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
        } else {
-           ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
-           ssh2_pkt_addstring_start(ssh);
-           ssh2_pkt_send(ssh);
+           pktout = ssh2_pkt_init(SSH2_MSG_IGNORE);
+           ssh2_pkt_addstring_start(pktout);
+           ssh2_pkt_send_noqueue(ssh, pktout);
+       }
+    } else if (code == TS_BRK) {
+       if (ssh->state == SSH_STATE_CLOSED
+           || ssh->state == SSH_STATE_PREPACKET) return;
+       if (ssh->version == 1) {
+           logevent("Unable to send BREAK signal in SSH1");
+       } else if (ssh->mainchan) {
+           pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+           ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
+           ssh2_pkt_addstring(pktout, "break");
+           ssh2_pkt_addbool(pktout, 0);
+           ssh2_pkt_adduint32(pktout, 0);   /* default break length */
+           ssh2_pkt_send(ssh, pktout);
        }
     } else {
-       /* do nothing */
+       /* Is is a POSIX signal? */
+       char *signame = NULL;
+       if (code == TS_SIGABRT) signame = "ABRT";
+       if (code == TS_SIGALRM) signame = "ALRM";
+       if (code == TS_SIGFPE)  signame = "FPE";
+       if (code == TS_SIGHUP)  signame = "HUP";
+       if (code == TS_SIGILL)  signame = "ILL";
+       if (code == TS_SIGINT)  signame = "INT";
+       if (code == TS_SIGKILL) signame = "KILL";
+       if (code == TS_SIGPIPE) signame = "PIPE";
+       if (code == TS_SIGQUIT) signame = "QUIT";
+       if (code == TS_SIGSEGV) signame = "SEGV";
+       if (code == TS_SIGTERM) signame = "TERM";
+       if (code == TS_SIGUSR1) signame = "USR1";
+       if (code == TS_SIGUSR2) signame = "USR2";
+       /* The SSH-2 protocol does in principle support arbitrary named
+        * signals, including signame@domain, but we don't support those. */
+       if (signame) {
+           /* It's a signal. */
+           if (ssh->version == 2 && ssh->mainchan) {
+               pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+               ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid);
+               ssh2_pkt_addstring(pktout, "signal");
+               ssh2_pkt_addbool(pktout, 0);
+               ssh2_pkt_addstring(pktout, signame);
+               ssh2_pkt_send(ssh, pktout);
+               logeventf(ssh, "Sent signal SIG%s", signame);
+           }
+       } else {
+           /* Never heard of it. Do nothing */
+       }
     }
 }
 
@@ -6290,6 +7323,7 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
 {
     struct ssh_channel *c = (struct ssh_channel *)channel;
     Ssh ssh = c->ssh;
+    struct Packet *pktout;
 
     logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
 
@@ -6301,27 +7335,26 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
                    //PKT_STR, <org:orgport>,
                    PKT_END);
     } else {
-       ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
-       ssh2_pkt_addstring(ssh, "direct-tcpip");
-       ssh2_pkt_adduint32(ssh, c->localid);
+       pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
+       ssh2_pkt_addstring(pktout, "direct-tcpip");
+       ssh2_pkt_adduint32(pktout, c->localid);
        c->v.v2.locwindow = OUR_V2_WINSIZE;
-       ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
-       ssh2_pkt_adduint32(ssh, 0x4000UL);      /* our max pkt size */
-       ssh2_pkt_addstring(ssh, hostname);
-       ssh2_pkt_adduint32(ssh, port);
+       ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */
+       ssh2_pkt_adduint32(pktout, 0x4000UL);      /* our max pkt size */
+       ssh2_pkt_addstring(pktout, hostname);
+       ssh2_pkt_adduint32(pktout, port);
        /*
         * We make up values for the originator data; partly it's
         * too much hassle to keep track, and partly I'm not
         * convinced the server should be told details like that
         * about my local network configuration.
         */
-       ssh2_pkt_addstring(ssh, "client-side-connection");
-       ssh2_pkt_adduint32(ssh, 0);
-       ssh2_pkt_send(ssh);
+       ssh2_pkt_addstring(pktout, "client-side-connection");
+       ssh2_pkt_adduint32(pktout, 0);
+       ssh2_pkt_send(ssh, pktout);
     }
 }
 
-
 static Socket ssh_socket(void *handle)
 {
     Ssh ssh = (Ssh) handle;
@@ -6359,7 +7392,10 @@ static void ssh_provide_logctx(void *handle, void *logctx)
 static int ssh_return_exitcode(void *handle)
 {
     Ssh ssh = (Ssh) handle;
-    return ssh->exitcode;
+    if (ssh->s != NULL)
+        return -1;
+    else
+        return (ssh->exitcode >= 0 ? ssh->exitcode : 0);
 }
 
 /*
@@ -6381,6 +7417,7 @@ Backend ssh_backend = {
     ssh_sendbuffer,
     ssh_size,
     ssh_special,
+    ssh_get_specials,
     ssh_socket,
     ssh_return_exitcode,
     ssh_sendok,