X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/db2197384bb9ad9c6d1e2aeef6fa5be5ab19df36..39934deb5202149f98198c111a35c21cb4d0d0f8:/ssh.c

diff --git a/ssh.c b/ssh.c
index 1078af0f..1d8e6b8d 100644
--- 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
@@ -310,20 +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 int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt);
-static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt);
+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
@@ -454,7 +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;
@@ -502,14 +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);
@@ -518,6 +540,9 @@ 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;
@@ -525,6 +550,7 @@ struct rdpkt1_state_tag {
     unsigned char *p;
     int i;
     int chunk;
+    struct Packet *pktin;
 };
 
 struct rdpkt2_state_tag {
@@ -532,8 +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 */
@@ -592,8 +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;
 
@@ -629,8 +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;
 
@@ -642,8 +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
@@ -658,6 +692,17 @@ struct ssh_tag {
      */
     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)
@@ -684,6 +729,25 @@ static void logeventf(Ssh ssh, const char *fmt, ...)
         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)
 {
     struct ssh_channel *a = (struct ssh_channel *) av;
@@ -797,48 +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);
@@ -848,111 +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(("Network attack (CRC compensation) detected!"));
-        crStop(0);
+	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_compute(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(("Incorrect CRC received on packet"));
-	crStop(0);
+	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;
 	if (!zlib_decompress_block(ssh->sc_comp_ctx,
-				   ssh->pktin.body - 1, ssh->pktin.length + 1,
+				   st->pktin->body - 1, st->pktin->length + 1,
 				   &decompblk, &decomplen)) {
 	    bombout(("Zlib decompression encountered invalid data"));
-	    crStop(0);
+	    ssh_free_packet(st->pktin);
+	    crStop(NULL);
 	}
 
-	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 (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(("Received data packet with bogus string length"));
-	    crStop(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(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
-	crStop(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
@@ -960,11 +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
@@ -972,20 +1037,20 @@ 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
@@ -993,7 +1058,8 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
      */
     if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
 	bombout(("Incoming packet was garbled on decryption"));
-	crStop(0);
+	ssh_free_packet(st->pktin);
+	crStop(NULL);
     }
 
     /*
@@ -1001,7 +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.
@@ -1010,14 +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.
@@ -1025,26 +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(("Incorrect MAC received on packet"));
-	crStop(0);
+	ssh_free_packet(st->pktin);
+	crStop(NULL);
     }
-    st->incoming_sequence++;	       /* whether or not we MACed */
+
+    st->pktin->sequence = st->incoming_sequence++;
 
     /*
      * Decompress packet payload.
@@ -1054,132 +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(("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);
-            crStop(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;
 
@@ -1187,29 +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;
@@ -1224,72 +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_compute(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) {
@@ -1316,63 +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)
@@ -1418,63 +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)
 {
@@ -1493,29 +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.
@@ -1524,11 +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);
 	}
     }
@@ -1541,67 +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)
 {
@@ -1615,6 +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)
 {
@@ -1639,56 +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(("internal error: Can't handle negative mpints"));
+    if (p[0] & 0x80)
 	return NULL;
-    }
     b = bignum_from_bytes((unsigned char *)p, length);
     return b;
 }
@@ -1700,7 +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;
@@ -1738,19 +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;
 	}
@@ -1758,8 +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);
 }
 
 /*
@@ -1782,7 +1942,7 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
 	 (!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, "OSU_1.4alpha3")))) {
+	  !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
@@ -1978,6 +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 {
@@ -1995,11 +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);
 
@@ -2037,15 +2200,13 @@ 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;
     }
@@ -2061,6 +2222,7 @@ static void ssh_do_close(Ssh ssh)
     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
@@ -2128,7 +2290,7 @@ static void ssh_sent(Plug plug, int bufsize)
  * freed by the caller.
  */
 static const char *connect_to_host(Ssh ssh, char *host, int port,
-				   char **realhost, int nodelay)
+				   char **realhost, int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
 	ssh_closing,
@@ -2169,9 +2331,10 @@ static const 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;
     }
 
@@ -2308,9 +2471,9 @@ static void ssh_agent_callback(void *sshv, void *reply, int replylen)
     ssh->agent_response_len = replylen;
 
     if (ssh->version == 1)
-	do_ssh1_login(ssh, NULL, -1, 0);
+	do_ssh1_login(ssh, NULL, -1, NULL);
     else
-	do_ssh2_authconn(ssh, NULL, -1, 0);
+	do_ssh2_authconn(ssh, NULL, -1, NULL);
 }
 
 static void ssh_agentf_callback(void *cv, void *reply, int replylen)
@@ -2330,8 +2493,10 @@ static void ssh_agentf_callback(void *cv, void *reply, int replylen)
     } 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)
@@ -2341,10 +2506,11 @@ static void ssh_agentf_callback(void *cv, void *reply, int replylen)
 /*
  * 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 {
@@ -2376,20 +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) {
+    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.
@@ -2404,9 +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;
@@ -2415,12 +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);
@@ -2454,11 +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");
@@ -2552,9 +2743,9 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 	sfree(hostkey.exponent);
 	hostkey.exponent = NULL;
     }
-    crWaitUntil(ispkt);
+    crWaitUntil(pktin);
 
-    if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
+    if (pktin->type != SSH1_SMSG_SUCCESS) {
 	bombout(("Encryption not successfully enabled"));
 	crStop(0);
     }
@@ -2563,7 +2754,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 
     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)) {
@@ -2582,7 +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)
@@ -2607,7 +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. */
@@ -2624,7 +2815,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     } 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) {
@@ -2644,12 +2835,12 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 			     ssh_agent_callback, ssh)) {
 		do {
 		    crReturn(0);
-		    if (ispkt) {
+		    if (pktin) {
 			bombout(("Unexpected data from server while waiting"
 				 " for agent response"));
 			crStop(0);
 		    }
-		} while (ispkt || inlen > 0);
+		} while (pktin || inlen > 0);
 		r = ssh->agent_response;
 		s->responselen = ssh->agent_response_len;
 	    }
@@ -2677,21 +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;
@@ -2719,13 +2939,13 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 			    sfree(agentreq);
 			    do {
 				crReturn(0);
-				if (ispkt) {
+				if (pktin) {
 				    bombout(("Unexpected data from server"
 					     " while waiting for agent"
 					     " response"));
 				    crStop(0);
 				}
-			    } while (ispkt || inlen > 0);
+			    } while (pktin || inlen > 0);
 			    vret = ssh->agent_response;
 			    retlen = ssh->agent_response_len;
 			} else
@@ -2738,8 +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) {
@@ -2782,19 +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) ?
@@ -2809,18 +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: ",
@@ -2889,7 +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)
@@ -2930,12 +3164,12 @@ 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) {
+	    if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
 		bombout(("Bizarre response to offer of public key"));
 		crStop(0);
 	    }
@@ -2945,7 +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 */
 
@@ -2965,13 +3202,13 @@ 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) {
+	    } else if (pktin->type != SSH1_SMSG_SUCCESS) {
 		bombout(("Bizarre response to RSA authentication response"));
 		crStop(0);
 	    }
@@ -3039,10 +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();
@@ -3079,8 +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_
@@ -3091,22 +3330,25 @@ 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(("Strange packet received, type %d", ssh->pktin.type));
+	} else if (pktin->type != SSH1_SMSG_SUCCESS) {
+	    bombout(("Strange packet received, type %d", pktin->type));
 	    crStop(0);
 	}
     }
@@ -3138,9 +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 */
@@ -3167,7 +3410,9 @@ int sshfwd_write(struct ssh_channel *c, char *buf, int len)
     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
@@ -3201,29 +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) {
+	} while (!pktin);
+	if (pktin->type != SSH1_SMSG_SUCCESS
+	    && pktin->type != SSH1_SMSG_FAILURE) {
 	    bombout(("Protocol confusion"));
 	    crStopV;
-	} else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+	} else if (pktin->type == SSH1_SMSG_FAILURE) {
 	    logevent("Agent forwarding refused");
 	} else {
 	    logevent("Agent forwarding enabled");
@@ -3248,12 +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) {
+	} while (!pktin);
+	if (pktin->type != SSH1_SMSG_SUCCESS
+	    && pktin->type != SSH1_SMSG_FAILURE) {
 	    bombout(("Protocol confusion"));
 	    crStopV;
-	} else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+	} else if (pktin->type == SSH1_SMSG_FAILURE) {
 	    logevent("X11 forwarding refused");
 	} else {
 	    logevent("X11 forwarding enabled");
@@ -3334,33 +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') {
-		    pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
-				   sport, ssh, &ssh->cfg);
-		    logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
-			      " doing SOCKS dynamic forwarding",
-			      (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
-			      (int)(*saddr?1:0), ":",
-			      (int)(sserv ? strlen(sports) : 0), sports,
-			      sserv, "(", sport, sserv, ")");
+		    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);
@@ -3385,18 +3637,19 @@ 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) {
+			} while (!pktin);
+			if (pktin->type != SSH1_SMSG_SUCCESS
+			    && pktin->type != SSH1_SMSG_FAILURE) {
 			    bombout(("Protocol confusion"));
 			    crStopV;
-			} else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+			} else if (pktin->type == SSH1_SMSG_FAILURE) {
 			    c_write_str(ssh, "Server refused port"
 					" forwarding\r\n");
 			}
 			logevent("Remote port forwarding enabled");
 		    }
 		}
+		sfree(sportdesc);
 	    }
 	}
     }
@@ -3418,12 +3671,12 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 	ssh->state = SSH_STATE_INTERMED;
 	do {
 	    crReturnV;
-	} while (!ispkt);
-	if (ssh->pktin.type != SSH1_SMSG_SUCCESS
-	    && 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 (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+	} else if (pktin->type == SSH1_SMSG_FAILURE) {
 	    c_write_str(ssh, "Server refused to allocate pty\r\n");
 	    ssh->editing = ssh->echoing = 1;
 	}
@@ -3437,12 +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) {
+	} while (!pktin);
+	if (pktin->type != SSH1_SMSG_SUCCESS
+	    && pktin->type != SSH1_SMSG_FAILURE) {
 	    bombout(("Protocol confusion"));
 	    crStopV;
-	} else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
+	} else if (pktin->type == SSH1_SMSG_FAILURE) {
 	    c_write_str(ssh, "Server refused to compress\r\n");
 	}
 	logevent("Started compression");
@@ -3486,32 +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) {
+	    } else if (pktin->type == SSH1_MSG_DISCONNECT) {
                 ssh_closing((Plug)ssh, NULL, 0, 0);
 		logevent("Received disconnect request");
 		crStopV;
-	    } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
+	    } 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);
@@ -3519,15 +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;
@@ -3539,19 +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;
@@ -3562,52 +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;
+		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;
@@ -3620,9 +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);
@@ -3644,8 +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);
@@ -3656,16 +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");
@@ -3682,7 +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 */
 		    }
@@ -3693,26 +3952,29 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 		    }
 		} else {
 		    bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n",
-			     ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
+			     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 = 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. */
@@ -3762,14 +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);
@@ -3784,14 +4046,15 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
                 ssh_closing((Plug)ssh, NULL, 0, 0);
                 crStopV;
 	    } else {
-		bombout(("Strange packet received: type %d", ssh->pktin.type));
+		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;
 	    }
@@ -3802,6 +4065,74 @@ static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 }
 
 /*
+ * Handle the top-level SSH2 protocol.
+ */
+static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
+{
+    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)
@@ -3860,7 +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;
@@ -3882,6 +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);
 
@@ -3948,105 +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
@@ -4056,7 +4399,7 @@ 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) {
+	if (pktin->type != SSH2_MSG_KEXINIT) {
 	    bombout(("expected key exchange packet from server"));
 	    crStop(0);
 	}
@@ -4068,8 +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))
@@ -4079,14 +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];
@@ -4112,7 +4455,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 	    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];
@@ -4138,21 +4481,21 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 	    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];
@@ -4161,7 +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];
@@ -4201,17 +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);
+	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(ispkt);
-	if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
+	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(ssh);
-	s->g = ssh2_pkt_getmp(ssh);
+	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);
+	}
 	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;
@@ -4227,18 +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);
+    s->pktout = ssh2_pkt_init(s->kex_init_value);
+    ssh2_pkt_addmp(s->pktout, s->e);
+    ssh2_pkt_send_noqueue(ssh, s->pktout);
 
-    crWaitUntil(ispkt);
-    if (ssh->pktin.type != s->kex_reply_value) {
+    crWaitUntil(pktin);
+    if (pktin->type != s->kex_reply_value) {
 	bombout(("expected key exchange reply packet from server"));
 	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->hostkeydata, &s->hostkeylen);
+    s->f = ssh2_pkt_getmp(pktin);
+    if (!s->f) {
+	bombout(("unable to parse key exchange reply packet"));
+	crStop(0);
+    }
+    ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
 
     s->K = dh_find_K(ssh->kex_ctx, s->f);
 
@@ -4289,14 +4640,21 @@ 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) {
+    crWaitUntil(pktin);
+    if (pktin->type != SSH2_MSG_NEWKEYS) {
 	bombout(("expected new-keys packet from server"));
 	crStop(0);
     }
@@ -4360,6 +4718,10 @@ 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);
@@ -4382,7 +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;
 
@@ -4392,7 +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");
@@ -4416,6 +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;
@@ -4425,11 +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;
     }
@@ -4457,18 +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 {
@@ -4492,7 +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;
@@ -4505,6 +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);
 
@@ -4513,11 +4892,11 @@ 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) {
+    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;
     }
@@ -4558,7 +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)) {
@@ -4576,7 +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)
@@ -4603,11 +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;
@@ -4646,8 +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;
 		/*
@@ -4659,20 +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
@@ -4682,9 +5061,9 @@ 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) {
+	    } else if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) {
 		bombout(("Strange packet received during authentication: type %d",
-			 ssh->pktin.type));
+			 pktin->type));
 		crStopV;
 	    }
 
@@ -4695,12 +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
@@ -4720,7 +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 */
@@ -4734,7 +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;
 			}
@@ -4786,12 +5169,12 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 				 ssh_agent_callback, ssh)) {
 		    do {
 			crReturnV;
-			if (ispkt) {
+			if (pktin) {
 			    bombout(("Unexpected data from server while"
 				     " waiting for agent response"));
 			    crStopV;
 			}
-		    } while (ispkt || inlen > 0);
+		    } while (pktin || inlen > 0);
 		    r = ssh->agent_response;
 		    s->responselen = ssh->agent_response_len;
 		}
@@ -4831,19 +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;
 			}
@@ -4859,17 +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 */
@@ -4893,9 +5276,9 @@ 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);
 			if (!agent_query(s->agentreq, s->len + 4,
@@ -4903,13 +5286,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 					 ssh_agent_callback, ssh)) {
 			    do {
 				crReturnV;
-				if (ispkt) {
+				if (pktin) {
 				    bombout(("Unexpected data from server"
 					     " while waiting for agent"
 					     " response"));
 				    crStopV;
 				}
-			    } while (ispkt || inlen > 0);
+			    } while (pktin || inlen > 0);
 			    vret = ssh->agent_response;
 			    s->retlen = ssh->agent_response_len;
 			}
@@ -4918,10 +5301,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 			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 {
@@ -4960,20 +5344,20 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 							  &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 */
@@ -4992,9 +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;
 		}
 	    }
@@ -5007,17 +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;
@@ -5045,9 +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");
@@ -5056,7 +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);
 		}
 
 		/*
@@ -5067,16 +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;
@@ -5101,12 +5494,12 @@ 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");
@@ -5121,7 +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)
@@ -5150,11 +5543,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 			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;
@@ -5166,15 +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:
@@ -5184,7 +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);
@@ -5194,19 +5587,19 @@ 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);
 		}
@@ -5225,14 +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
@@ -5258,29 +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
@@ -5298,12 +5695,12 @@ 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);
+		ssh2_pkt_addstring(s->pktout, "en");	/* language tag */
+		ssh2_pkt_send_noqueue(ssh, s->pktout);
                 ssh_closing((Plug)ssh, NULL, 0, 0);
 		crStopV;
 	    }
@@ -5316,74 +5713,76 @@ 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(("Server refused to open a session"));
-	crStopV;
-	/* FIXME: error data comes back in FAILURE packet */
-    }
-    if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
-	bombout(("Server's channel confirmation cited wrong channel"));
-	crStopV;
-    }
-    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) {
+	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", ssh->pktin.type));
+			 " packet type %d", pktin->type));
 		crStopV;
 	    }
 	    logevent("X11 forwarding refused");
@@ -5469,27 +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') {
-		    pfd_addforward(NULL, -1, *saddr ? saddr : NULL,
-				   sport, ssh, &ssh->cfg);
-		    logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
-			      " doing SOCKS dynamic forwarding",
-			      (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
-			      (int)(*saddr?1:0), ":",
-			      (int)(sserv ? strlen(sports) : 0), sports,
-			      sserv, "(", sport, sserv, ")");
+		    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);
@@ -5501,46 +5914,32 @@ 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) {
+			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));
+					 pktin->type));
 				crStopV;
 			    }
 			    logevent("Server refused this port forwarding");
@@ -5549,6 +5948,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 			}
 		    }
 		}
+		sfree(sportdesc);
 	    }
 	}
     }
@@ -5556,30 +5956,20 @@ 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);
+	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);
 
-	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) {
+	if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
+	    if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
 		bombout(("Unexpected response to agent forwarding request:"
-			 " packet type %d", ssh->pktin.type));
+			 " packet type %d", pktin->type));
 		crStopV;
 	    }
 	    logevent("Agent forwarding refused");
@@ -5592,46 +5982,36 @@ 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) {
+    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. */
-	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_addbyte(ssh, 128);	       /* TTY_OP_ISPEED */
-	ssh2_pkt_adduint32(ssh, ssh->ispeed);
-	ssh2_pkt_addbyte(ssh, 129);	       /* TTY_OP_OSPEED */
-	ssh2_pkt_adduint32(ssh, ssh->ospeed);
-	ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END */
-	ssh2_pkt_send(ssh);
+	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) {
+	if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) {
+	    if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) {
 		bombout(("Unexpected response to pty request:"
-			 " packet type %d", ssh->pktin.type));
+			 " packet type %d", pktin->type));
 		crStopV;
 	    }
 	    c_write_str(ssh, "Server refused to allocate pty\r\n");
@@ -5645,11 +6025,77 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     }
 
     /*
+     * 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;
 
@@ -5661,36 +6107,28 @@ 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) {
+	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", ssh->pktin.type));
+			 " packet type %d", pktin->type));
 		crStopV;
 	    }
 	    /*
@@ -5723,31 +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 = 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;
@@ -5806,8 +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);
@@ -5827,8 +6266,8 @@ 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);
@@ -5840,7 +6279,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 		/* 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);
@@ -5856,9 +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);
@@ -5866,8 +6307,10 @@ 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
                     /*
@@ -5881,36 +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.
                      */
-		    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_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) {
@@ -5920,12 +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)
@@ -5933,21 +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,
@@ -5959,11 +6414,11 @@ 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);
+		    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;
@@ -5974,18 +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 {
 		    /*
@@ -5994,18 +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
@@ -6014,10 +6546,10 @@ 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;
@@ -6026,22 +6558,25 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 		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);
+		remid = ssh_pkt_getuint32(pktin);
+		winsize = ssh_pkt_getuint32(pktin);
+		pktsize = ssh_pkt_getuint32(pktin);
 
 		if (typelen == 3 && !memcmp(type, "x11", 3)) {
 		    char *addrstr;
 
-                    ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
+                    ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen);
 		    addrstr = snewn(peeraddrlen+1, char);
 		    memcpy(addrstr, peeraddr, peeraddrlen);
-		    peeraddr[peeraddrlen] = '\0';
-                    peerport = ssh2_pkt_getuint32(ssh);
+		    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";
@@ -6050,6 +6585,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 				      &ssh->cfg) != NULL) {
 			error = "Unable to open an X11 connection";
 		    } else {
+			logevent("Opening X11 forward connection succeeded");
 			c->type = CHAN_X11;
 		    }
 
@@ -6059,11 +6595,13 @@ 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);
-                    ssh2_pkt_getstring(ssh, &peeraddr, &peeraddrlen);
-                    peerport = 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 {
@@ -6071,8 +6609,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 						       realpf->dhost,
 						       realpf->dport, c,
 						       &ssh->cfg);
-			logeventf(ssh, "Received remote port open request"
-				  " for %s:%d", realpf->dhost, realpf->dport);
+			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";
@@ -6095,12 +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);
@@ -6110,18 +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(("Strange packet received: type %d", ssh->pktin.type));
+		bombout(("Strange packet received: type %d", pktin->type));
 		crStopV;
 	    }
-	} else {
+	} else if (ssh->mainchan) {
 	    /*
 	     * We have spare data. Add it to the channel buffer.
 	     */
@@ -6165,13 +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)
+{
+    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 (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
+    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);
+    }
 }
 
 /*
@@ -6181,7 +6855,8 @@ static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
  */
 static const char *ssh_init(void *frontend_handle, void **backend_handle,
 			    Config *cfg,
-			    char *host, int port, char **realhost, int nodelay)
+			    char *host, int port, char **realhost, int nodelay,
+			    int keepalive)
 {
     const char *p;
     Ssh ssh;
@@ -6214,10 +6889,6 @@ static const 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;
@@ -6230,7 +6901,7 @@ static const 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;
@@ -6241,6 +6912,9 @@ static const 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;
 
@@ -6265,7 +6939,11 @@ static const 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;
 
@@ -6304,6 +6982,10 @@ static void ssh_free(void *handle)
 	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) {
@@ -6333,25 +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->pktout.data) {
-	sfree(ssh->pktout.data);
-	ssh->pktout.data = NULL;
-    }
-    if (ssh->pktin.data) {
-	sfree(ssh->pktin.data);
-	ssh->pktin.data = NULL;
-    }
     if (ssh->crcda_ctx) {
 	crcda_free_context(ssh->crcda_ctx);
 	ssh->crcda_ctx = NULL;
     }
-    if (ssh->logctx) {
-	log_free(ssh->logctx);
-	ssh->logctx = NULL;
-    }
     if (ssh->s)
 	ssh_do_close(ssh);
     sfree(ssh);
+    if (ssh->pinger)
+	pinger_free(ssh->pinger);
 }
 
 /*
@@ -6366,6 +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 */
 }
 
@@ -6422,6 +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;
@@ -6441,16 +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;
@@ -6463,23 +7137,62 @@ static void ssh_size(void *handle, int width, int height)
  */
 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) {
-	static const struct telnet_special ssh1_specials[] = {
-	    {"IGNORE message", TS_NOP},
-	    {NULL, 0}
-	};
-	return ssh1_specials;
+	/* 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) {
-	static const struct telnet_special ssh2_specials[] = {
-	    {"Break", TS_BRK},
-	    {"IGNORE message", TS_NOP},
-	    {NULL, 0}
-	};
-	return ssh2_specials;
-    } else
+	/* 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
 }
 
 /*
@@ -6490,6 +7203,7 @@ static const struct telnet_special *ssh_get_specials(void *handle)
 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) {
@@ -6503,10 +7217,10 @@ 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 || code == TS_NOP) {
@@ -6516,25 +7230,55 @@ static void ssh_special(void *handle, Telnet_Special code)
 	    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 {
-	    ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
-	    ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
-	    ssh2_pkt_addstring(ssh, "break");
-	    ssh2_pkt_addbool(ssh, 0);
-	    ssh2_pkt_adduint32(ssh, 0);   /* default break length */
-	    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, "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 */
+	}
     }
 }
 
@@ -6579,6 +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);
 
@@ -6590,27 +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;