Revamp of the local X11 connection code. We now parse X display
[u/mdw/putty] / ssh.c
diff --git a/ssh.c b/ssh.c
index 809f4af..d30626d 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -12,6 +12,7 @@
 #include "putty.h"
 #include "tree234.h"
 #include "ssh.h"
+#include "sshgss.h"
 
 #ifndef FALSE
 #define FALSE 0
 #define SSH1_SMSG_AUTH_CCARD_CHALLENGE            71   /* 0x47 */
 #define SSH1_CMSG_AUTH_CCARD_RESPONSE             72   /* 0x48 */
 
+#define SSH1_AUTH_RHOSTS                          1    /* 0x1 */
+#define SSH1_AUTH_RSA                             2    /* 0x2 */
+#define SSH1_AUTH_PASSWORD                        3    /* 0x3 */
+#define SSH1_AUTH_RHOSTS_RSA                      4    /* 0x4 */
 #define SSH1_AUTH_TIS                             5    /* 0x5 */
 #define SSH1_AUTH_CCARD                           16   /* 0x10 */
 
 #define SSH2_MSG_CHANNEL_REQUEST                  98   /* 0x62 */
 #define SSH2_MSG_CHANNEL_SUCCESS                  99   /* 0x63 */
 #define SSH2_MSG_CHANNEL_FAILURE                  100  /* 0x64 */
+#define SSH2_MSG_USERAUTH_GSSAPI_RESPONSE               60
+#define SSH2_MSG_USERAUTH_GSSAPI_TOKEN                  61
+#define SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE      63
+#define SSH2_MSG_USERAUTH_GSSAPI_ERROR                  64
+#define SSH2_MSG_USERAUTH_GSSAPI_ERRTOK                 65
+#define SSH2_MSG_USERAUTH_GSSAPI_MIC                    66
 
 /*
  * Packet type contexts, so that ssh2_pkt_type can correctly decode
  * the ambiguous type numbers back into the correct type strings.
  */
-#define SSH2_PKTCTX_DHGROUP          0x0001
-#define SSH2_PKTCTX_DHGEX            0x0002
-#define SSH2_PKTCTX_RSAKEX           0x0004
-#define SSH2_PKTCTX_KEX_MASK         0x000F
-#define SSH2_PKTCTX_PUBLICKEY        0x0010
-#define SSH2_PKTCTX_PASSWORD         0x0020
-#define SSH2_PKTCTX_KBDINTER         0x0040
-#define SSH2_PKTCTX_AUTH_MASK        0x00F0
+typedef enum {
+    SSH2_PKTCTX_NOKEX,
+    SSH2_PKTCTX_DHGROUP,
+    SSH2_PKTCTX_DHGEX,
+    SSH2_PKTCTX_RSAKEX
+} Pkt_KCtx;
+typedef enum {
+    SSH2_PKTCTX_NOAUTH,
+    SSH2_PKTCTX_PUBLICKEY,
+    SSH2_PKTCTX_PASSWORD,
+    SSH2_PKTCTX_GSSAPI,
+    SSH2_PKTCTX_KBDINTER
+} Pkt_ACtx;
 
 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1  /* 0x1 */
 #define SSH2_DISCONNECT_PROTOCOL_ERROR            2    /* 0x2 */
@@ -175,11 +191,12 @@ static const char *const ssh2_disconnect_reasons[] = {
 #define BUG_SSH2_DERIVEKEY                       32
 #define BUG_SSH2_REKEY                           64
 #define BUG_SSH2_PK_SESSIONID                   128
+#define BUG_SSH2_MAXPKT                                256
 
 /*
  * Codes for terminal modes.
  * Most of these are the same in SSH-1 and SSH-2.
- * This list is derived from draft-ietf-secsh-connect-25 and
+ * This list is derived from RFC 4254 and
  * SSH-1 RFC-1.2.31.
  */
 static const struct {
@@ -281,7 +298,8 @@ static unsigned int ssh_tty_parse_boolean(char *s)
 }
 
 #define translate(x) if (type == x) return #x
-#define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
+#define translatek(x,ctx) if (type == x && (pkt_kctx == ctx)) return #x
+#define translatea(x,ctx) if (type == x && (pkt_actx == ctx)) return #x
 static char *ssh1_pkt_type(int type)
 {
     translate(SSH1_MSG_DISCONNECT);
@@ -327,8 +345,14 @@ static char *ssh1_pkt_type(int type)
     translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
     return "unknown";
 }
-static char *ssh2_pkt_type(int pkt_ctx, int type)
+static char *ssh2_pkt_type(Pkt_KCtx pkt_kctx, Pkt_ACtx pkt_actx, int type)
 {
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_ERROR,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,SSH2_PKTCTX_GSSAPI);
+    translatea(SSH2_MSG_USERAUTH_GSSAPI_MIC, SSH2_PKTCTX_GSSAPI);
     translate(SSH2_MSG_DISCONNECT);
     translate(SSH2_MSG_IGNORE);
     translate(SSH2_MSG_UNIMPLEMENTED);
@@ -337,23 +361,23 @@ static char *ssh2_pkt_type(int pkt_ctx, int type)
     translate(SSH2_MSG_SERVICE_ACCEPT);
     translate(SSH2_MSG_KEXINIT);
     translate(SSH2_MSG_NEWKEYS);
-    translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
-    translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
-    translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
-    translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
-    translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
-    translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
-    translatec(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
-    translatec(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
-    translatec(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
+    translatek(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP);
+    translatek(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP);
+    translatek(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
+    translatek(SSH2_MSG_KEXRSA_PUBKEY, SSH2_PKTCTX_RSAKEX);
+    translatek(SSH2_MSG_KEXRSA_SECRET, SSH2_PKTCTX_RSAKEX);
+    translatek(SSH2_MSG_KEXRSA_DONE, SSH2_PKTCTX_RSAKEX);
     translate(SSH2_MSG_USERAUTH_REQUEST);
     translate(SSH2_MSG_USERAUTH_FAILURE);
     translate(SSH2_MSG_USERAUTH_SUCCESS);
     translate(SSH2_MSG_USERAUTH_BANNER);
-    translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
-    translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
-    translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
-    translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
+    translatea(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
+    translatea(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
+    translatea(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
+    translatea(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
     translate(SSH2_MSG_GLOBAL_REQUEST);
     translate(SSH2_MSG_REQUEST_SUCCESS);
     translate(SSH2_MSG_REQUEST_FAILURE);
@@ -465,11 +489,15 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
  * 
  *  - OUR_V2_WINSIZE is the maximum window size we present on SSH-2
  *    channels.
+ *
+ *  - OUR_V2_BIGWIN is the window size we advertise for the only
+ *    channel in a simple connection.  It must be <= INT_MAX.
  */
 
 #define SSH1_BUFFER_LIMIT 32768
 #define SSH_MAX_BACKLOG 32768
 #define OUR_V2_WINSIZE 16384
+#define OUR_V2_BIGWIN 0x7fffffff
 #define OUR_V2_MAXPKT 0x4000UL
 
 /* Maximum length of passwords/passphrases (arbitrary) */
@@ -520,6 +548,14 @@ enum {                                    /* channel types */
 };
 
 /*
+ * little structure to keep track of outstanding WINDOW_ADJUSTs
+ */
+struct winadj {
+    struct winadj *next;
+    unsigned size;
+};
+
+/*
  * 2-3-4 tree storing channels.
  */
 struct ssh_channel {
@@ -539,14 +575,29 @@ struct ssh_channel {
      * A channel is completely finished with when all four bits are set.
      */
     int closes;
+    /*
+     * True if this channel is causing the underlying connection to be
+     * throttled.
+     */
+    int throttling_conn;
     union {
-       struct ssh1_data_channel {
-           int throttling;
-       } v1;
        struct ssh2_data_channel {
            bufchain outbuffer;
            unsigned remwindow, remmaxpkt;
-           unsigned locwindow;
+           /* locwindow is signed so we can cope with excess data. */
+           int locwindow, locmaxwin;
+           /*
+            * remlocwin is the amount of local window that we think
+            * the remote end had available to it after it sent the
+            * last data packet or window adjust ack.
+            */
+           int remlocwin;
+           /*
+            * These store the list of window adjusts that haven't
+            * been acked.
+            */
+           struct winadj *winadj_head, *winadj_tail;
+           enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
        } v2;
     } v;
     union {
@@ -653,7 +704,7 @@ static void ssh_special(void *handle, Telnet_Special);
 static int ssh2_try_send(struct ssh_channel *c);
 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
-static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
+static void ssh2_set_window(struct ssh_channel *c, int newwin);
 static int ssh_sendbuffer(void *handle);
 static int ssh_do_close(Ssh ssh, int notify_exit);
 static unsigned long ssh_pkt_getuint32(struct Packet *pkt);
@@ -770,12 +821,13 @@ struct ssh_tag {
 
     bufchain banner;   /* accumulates banners during do_ssh2_authconn */
 
-    int pkt_ctx;
+    Pkt_KCtx pkt_kctx;
+    Pkt_ACtx pkt_actx;
 
-    void *x11auth;
+    struct X11Display *x11disp;
 
     int version;
-    int v1_throttle_count;
+    int conn_throttle_count;
     int overall_bufsize;
     int throttled_all;
     int v1_stdout_throttling;
@@ -858,6 +910,11 @@ struct ssh_tag {
     int kex_in_progress;
     long next_rekey, last_rekey;
     char *deferred_rekey_reason;    /* points to STATIC string; don't free */
+
+    /*
+     * Fully qualified host name, which we need if doing GSSAPI.
+     */
+    char *fullhostname;
 };
 
 #define logevent(s) logevent(ssh->frontend, s)
@@ -1215,9 +1272,9 @@ static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
            /* "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;
+           } else if (st->pktin->type == SSH1_MSG_CHANNEL_DATA) {
+               do_blank = TRUE; blank_prefix = 8;
            }
            if (do_blank) {
                blank.offset = blank_prefix;
@@ -1230,7 +1287,7 @@ static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
                   PKT_INCOMING, st->pktin->type,
                   ssh1_pkt_type(st->pktin->type),
                   st->pktin->body, st->pktin->length,
-                  nblanks, &blank);
+                  nblanks, &blank, NULL);
     }
 
     crFinish(st->pktin);
@@ -1375,9 +1432,9 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
            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;
+           } else if (st->pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
+               do_blank = TRUE; blank_prefix = 12;
            }
            if (do_blank) {
                blank.offset = blank_prefix;
@@ -1387,9 +1444,10 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
            }
        }
        log_packet(ssh->logctx, PKT_INCOMING, st->pktin->type,
-                  ssh2_pkt_type(ssh->pkt_ctx, st->pktin->type),
+                  ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
+                                st->pktin->type),
                   st->pktin->data+6, st->pktin->length-6,
-                  nblanks, &blank);
+                  nblanks, &blank, &st->pktin->sequence);
     }
 
     crFinish(st->pktin);
@@ -1414,7 +1472,7 @@ static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
        log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[12],
                   ssh1_pkt_type(pkt->data[12]),
                   pkt->body, pkt->length - (pkt->body - pkt->data),
-                  pkt->nblanks, pkt->blanks);
+                  pkt->nblanks, pkt->blanks, NULL);
     sfree(pkt->blanks); pkt->blanks = NULL;
     pkt->nblanks = 0;
 
@@ -1453,7 +1511,9 @@ static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt, int *offset_p)
 
 static int s_write(Ssh ssh, void *data, int len)
 {
-    log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len, 0, NULL);
+    if (ssh->logctx)
+       log_packet(ssh->logctx, PKT_OUTGOING, -1, NULL, data, len,
+                  0, NULL, NULL);
     return sk_write(ssh->s, (char *)data, len);
 }
 
@@ -1734,9 +1794,9 @@ static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt)
 
     if (ssh->logctx)
        log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5],
-                  ssh2_pkt_type(ssh->pkt_ctx, pkt->data[5]),
+                  ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx, pkt->data[5]),
                   pkt->body, pkt->length - (pkt->body - pkt->data),
-                  pkt->nblanks, pkt->blanks);
+                  pkt->nblanks, pkt->blanks, &ssh->v2_outgoing_sequence);
     sfree(pkt->blanks); pkt->blanks = NULL;
     pkt->nblanks = 0;
 
@@ -2352,6 +2412,17 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring)
        ssh->remote_bugs |= BUG_SSH2_REKEY;
        logevent("We believe remote version has SSH-2 rekey bug");
     }
+
+    if (ssh->cfg.sshbug_maxpkt2 == FORCE_ON ||
+       (ssh->cfg.sshbug_maxpkt2 == AUTO &&
+        (wc_match("1.36_sshlib GlobalSCAPE", imp) ||
+          wc_match("1.36 sshlib: GlobalScape", imp)))) {
+       /*
+        * This version ignores our makpkt and needs to be throttled.
+        */
+       ssh->remote_bugs |= BUG_SSH2_MAXPKT;
+       logevent("We believe remote version ignores SSH-2 maximum packet size");
+    }
 }
 
 /*
@@ -2377,6 +2448,47 @@ static void ssh_fix_verstring(char *str)
     }
 }
 
+/*
+ * Send an appropriate SSH version string.
+ */
+static void ssh_send_verstring(Ssh ssh, char *svers)
+{
+    char *verstring;
+
+    if (ssh->version == 2) {
+       /*
+        * Construct a v2 version string.
+        */
+       verstring = dupprintf("SSH-2.0-%s\015\012", sshver);
+    } else {
+       /*
+        * Construct a v1 version string.
+        */
+       verstring = dupprintf("SSH-%s-%s\012",
+                             (ssh_versioncmp(svers, "1.5") <= 0 ?
+                              svers : "1.5"),
+                             sshver);
+    }
+
+    ssh_fix_verstring(verstring);
+
+    if (ssh->version == 2) {
+       size_t len;
+       /*
+        * Record our version string.
+        */
+       len = strcspn(verstring, "\015\012");
+       ssh->v_c = snewn(len + 1, char);
+       memcpy(ssh->v_c, verstring, len);
+       ssh->v_c[len] = 0;
+    }
+
+    logeventf(ssh, "We claim version: %.*s",
+             strcspn(verstring, "\015\012"), verstring);
+    s_write(ssh, verstring, strlen(verstring));
+    sfree(verstring);
+}
+
 static int do_ssh_init(Ssh ssh, unsigned char c)
 {
     struct do_ssh_init_state {
@@ -2455,65 +2567,43 @@ static int do_ssh_init(Ssh ssh, unsigned char c)
        crStop(0);
     }
 
-    {
-        char *verstring;
+    if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1))
+       ssh->version = 2;
+    else
+       ssh->version = 1;
 
-        if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) {
-            /*
-             * Construct a v2 version string.
-             */
-            verstring = dupprintf("SSH-2.0-%s\015\012", sshver);
-            ssh->version = 2;
-        } else {
-            /*
-             * Construct a v1 version string.
-             */
-            verstring = dupprintf("SSH-%s-%s\012",
-                                  (ssh_versioncmp(s->version, "1.5") <= 0 ?
-                                   s->version : "1.5"),
-                                  sshver);
-            ssh->version = 1;
-        }
+    logeventf(ssh, "Using SSH protocol version %d", ssh->version);
 
-        ssh_fix_verstring(verstring);
+    /* Send the version string, if we haven't already */
+    if (ssh->cfg.sshprot != 3)
+       ssh_send_verstring(ssh, s->version);
 
-        if (ssh->version == 2) {
-           size_t len;
-            /*
-             * Hash our version string and their version string.
-             */
-           len = strcspn(verstring, "\015\012");
-           ssh->v_c = snewn(len + 1, char);
-           memcpy(ssh->v_c, verstring, len);
-           ssh->v_c[len] = 0;
-           len = strcspn(s->vstring, "\015\012");
-           ssh->v_s = snewn(len + 1, char);
-           memcpy(ssh->v_s, s->vstring, len);
-           ssh->v_s[len] = 0;
+    if (ssh->version == 2) {
+       size_t len;
+       /*
+        * Record their version string.
+        */
+       len = strcspn(s->vstring, "\015\012");
+       ssh->v_s = snewn(len + 1, char);
+       memcpy(ssh->v_s, s->vstring, len);
+       ssh->v_s[len] = 0;
            
-            /*
-             * Initialise SSH-2 protocol.
-             */
-            ssh->protocol = ssh2_protocol;
-            ssh2_protocol_setup(ssh);
-            ssh->s_rdpkt = ssh2_rdpkt;
-        } else {
-            /*
-             * Initialise SSH-1 protocol.
-             */
-            ssh->protocol = ssh1_protocol;
-            ssh1_protocol_setup(ssh);
-            ssh->s_rdpkt = ssh1_rdpkt;
-        }
-        logeventf(ssh, "We claim version: %.*s",
-                  strcspn(verstring, "\015\012"), verstring);
-       s_write(ssh, verstring, strlen(verstring));
-        sfree(verstring);
-       if (ssh->version == 2)
-           do_ssh2_transport(ssh, NULL, -1, NULL);
+       /*
+        * Initialise SSH-2 protocol.
+        */
+       ssh->protocol = ssh2_protocol;
+       ssh2_protocol_setup(ssh);
+       ssh->s_rdpkt = ssh2_rdpkt;
+    } else {
+       /*
+        * Initialise SSH-1 protocol.
+        */
+       ssh->protocol = ssh1_protocol;
+       ssh1_protocol_setup(ssh);
+       ssh->s_rdpkt = ssh1_rdpkt;
     }
-
-    logeventf(ssh, "Using SSH protocol version %d", ssh->version);
+    if (ssh->version == 2)
+       do_ssh2_transport(ssh, NULL, -1, NULL);
 
     update_specials_menu(ssh->frontend);
     ssh->state = SSH_STATE_BEFORE_SIZE;
@@ -2573,7 +2663,9 @@ static void ssh_set_frozen(Ssh ssh, int frozen)
 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
 {
     /* Log raw data, if we're in that mode. */
-    log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen, 0, NULL);
+    if (ssh->logctx)
+       log_packet(ssh->logctx, PKT_INCOMING, -1, NULL, data, datalen,
+                  0, NULL, NULL);
 
     crBegin(ssh->ssh_gotdata_crstate);
 
@@ -2766,12 +2858,30 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
     SockAddr addr;
     const char *err;
 
-    ssh->savedhost = snewn(1 + strlen(host), char);
-    strcpy(ssh->savedhost, host);
+    if (*ssh->cfg.loghost) {
+       char *colon;
 
-    if (port < 0)
-       port = 22;                     /* default ssh port */
-    ssh->savedport = port;
+       ssh->savedhost = dupstr(ssh->cfg.loghost);
+       ssh->savedport = 22;           /* default ssh port */
+
+       /*
+        * A colon suffix on savedhost also lets us affect
+        * savedport.
+        * 
+        * (FIXME: do something about IPv6 address literals here.)
+        */
+       colon = strrchr(ssh->savedhost, ':');
+       if (colon) {
+           *colon++ = '\0';
+           if (*colon)
+               ssh->savedport = atoi(colon);
+       }
+    } else {
+       ssh->savedhost = dupstr(host);
+       if (port < 0)
+           port = 22;                 /* default ssh port */
+       ssh->savedport = port;
+    }
 
     /*
      * Try to find host.
@@ -2785,6 +2895,7 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
        sk_addr_free(addr);
        return err;
     }
+    ssh->fullhostname = dupstr(*realhost);   /* save in case of GSSAPI */
 
     /*
      * Open socket.
@@ -2798,20 +2909,39 @@ static const char *connect_to_host(Ssh ssh, char *host, int port,
        return err;
     }
 
+    /*
+     * If the SSH version number's fixed, set it now, and if it's SSH-2,
+     * send the version string too.
+     */
+    if (ssh->cfg.sshprot == 0)
+       ssh->version = 1;
+    if (ssh->cfg.sshprot == 3) {
+       ssh->version = 2;
+       ssh_send_verstring(ssh, NULL);
+    }
+
+    /*
+     * loghost, if configured, overrides realhost.
+     */
+    if (*ssh->cfg.loghost) {
+       sfree(*realhost);
+       *realhost = dupstr(ssh->cfg.loghost);
+    }
+
     return NULL;
 }
 
 /*
  * Throttle or unthrottle the SSH connection.
  */
-static void ssh1_throttle(Ssh ssh, int adjust)
+static void ssh_throttle_conn(Ssh ssh, int adjust)
 {
-    int old_count = ssh->v1_throttle_count;
-    ssh->v1_throttle_count += adjust;
-    assert(ssh->v1_throttle_count >= 0);
-    if (ssh->v1_throttle_count && !old_count) {
+    int old_count = ssh->conn_throttle_count;
+    ssh->conn_throttle_count += adjust;
+    assert(ssh->conn_throttle_count >= 0);
+    if (ssh->conn_throttle_count && !old_count) {
        ssh_set_frozen(ssh, 1);
-    } else if (!ssh->v1_throttle_count && old_count) {
+    } else if (!ssh->conn_throttle_count && old_count) {
        ssh_set_frozen(ssh, 0);
     }
 }
@@ -2899,8 +3029,8 @@ 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,
+                   PKTT_DATA,
                    PKT_DATA, sentreply, replylen,
                    PKTT_OTHER,
                    PKT_END);
@@ -3021,6 +3151,8 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
     ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin);
     s->supported_ciphers_mask = ssh_pkt_getuint32(pktin);
     s->supported_auths_mask = ssh_pkt_getuint32(pktin);
+    if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA))
+       s->supported_auths_mask &= ~(1 << SSH1_AUTH_RSA);
 
     ssh->v1_local_protoflags =
        ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
@@ -3274,7 +3406,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
 
     crWaitUntil(pktin);
 
-    if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
+    if ((s->supported_auths_mask & (1 << SSH1_AUTH_RSA)) == 0) {
        /* We must not attempt PK auth. Pretend we've already tried it. */
        s->tried_publickey = s->tried_agent = 1;
     } else {
@@ -3731,6 +3863,10 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen,
            }
        }
        if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
+           if ((s->supported_auths_mask & (1 << SSH1_AUTH_PASSWORD)) == 0) {
+               bombout(("No supported authentication methods available"));
+               crStop(0);
+           }
            s->cur_prompt->to_server = TRUE;
            s->cur_prompt->name = dupstr("SSH password");
            add_prompt(s->cur_prompt, dupprintf("%.90s@%.90s's password: ",
@@ -3960,8 +4096,7 @@ 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,
-                   PKTT_DATA,
-                   PKT_INT, len, PKT_DATA, buf, len,
+                   PKT_INT, len, PKTT_DATA, PKT_DATA, buf, len,
                    PKTT_OTHER, PKT_END);
        /*
         * In SSH-1 we can return 0 here - implying that forwarded
@@ -3980,17 +4115,20 @@ int sshfwd_write(struct ssh_channel *c, char *buf, int len)
 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
 {
     Ssh ssh = c->ssh;
+    int buflimit;
 
     if (ssh->state == SSH_STATE_CLOSED)
        return;
 
     if (ssh->version == 1) {
-       if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
-           c->v.v1.throttling = 0;
-           ssh1_throttle(ssh, -1);
-       }
+       buflimit = SSH1_BUFFER_LIMIT;
     } else {
-       ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
+       buflimit = c->v.v2.locmaxwin;
+       ssh2_set_window(c, bufsize < buflimit ? buflimit - bufsize : 0);
+    }
+    if (c->throttling_conn && bufsize <= buflimit) {
+       c->throttling_conn = 0;
+       ssh_throttle_conn(ssh, -1);
     }
 }
 
@@ -4419,7 +4557,7 @@ static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
                           string, stringlen);
     if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
        ssh->v1_stdout_throttling = 1;
-       ssh1_throttle(ssh, +1);
+       ssh_throttle_conn(ssh, +1);
     }
 }
 
@@ -4440,8 +4578,8 @@ static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
        c = snew(struct ssh_channel);
        c->ssh = ssh;
 
-       if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
-                    ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) {
+       if (x11_init(&c->u.x11.s, ssh->x11disp, c,
+                    NULL, -1, &ssh->cfg) != NULL) {
            logevent("Opening X11 forward connection failed");
            sfree(c);
            send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
@@ -4453,7 +4591,7 @@ static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin)
            c->halfopen = FALSE;
            c->localid = alloc_channel_id(ssh);
            c->closes = 0;
-           c->v.v1.throttling = 0;
+           c->throttling_conn = 0;
            c->type = CHAN_X11; /* identify channel type */
            add234(ssh->channels, c);
            send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
@@ -4482,7 +4620,7 @@ static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin)
        c->halfopen = FALSE;
        c->localid = alloc_channel_id(ssh);
        c->closes = 0;
-       c->v.v1.throttling = 0;
+       c->throttling_conn = 0;
        c->type = CHAN_AGENT;   /* identify channel type */
        c->u.a.lensofar = 0;
        add234(ssh->channels, c);
@@ -4536,7 +4674,7 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin)
            c->halfopen = FALSE;
            c->localid = alloc_channel_id(ssh);
            c->closes = 0;
-           c->v.v1.throttling = 0;
+           c->throttling_conn = 0;
            c->type = CHAN_SOCKDATA;    /* identify channel type */
            add234(ssh->channels, c);
            send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
@@ -4558,7 +4696,7 @@ static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
        c->remoteid = localid;
        c->halfopen = FALSE;
        c->type = CHAN_SOCKDATA;
-       c->v.v1.throttling = 0;
+       c->throttling_conn = 0;
        pfd_confirm(c->u.pfd.s);
     }
 
@@ -4694,9 +4832,9 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin)
            bufsize = 0;   /* agent channels never back up */
            break;
        }
-       if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
-           c->v.v1.throttling = 1;
-           ssh1_throttle(ssh, +1);
+       if (!c->throttling_conn && bufsize > SSH1_BUFFER_LIMIT) {
+           c->throttling_conn = 1;
+           ssh_throttle_conn(ssh, +1);
        }
     }
 }
@@ -4776,11 +4914,9 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
     }
 
     if (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);
+       ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                        ssh->cfg.x11_auth, &ssh->cfg);
        /*
         * Note that while we blank the X authentication data here, we don't
         * take any special action to blank the start of an X11 channel,
@@ -4790,14 +4926,19 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
         */
        if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
            send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
-                       PKT_STR, proto,
-                       PKTT_PASSWORD, PKT_STR, data, PKTT_OTHER,
-                       PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
+                       PKT_STR, ssh->x11disp->remoteauthprotoname,
+                       PKTT_PASSWORD,
+                       PKT_STR, ssh->x11disp->remoteauthdatastring,
+                       PKTT_OTHER,
+                       PKT_INT, ssh->x11disp->screennum,
                        PKT_END);
        } else {
            send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
-                       PKT_STR, proto,
-                       PKTT_PASSWORD, PKT_STR, data, PKTT_OTHER, PKT_END);
+                       PKT_STR, ssh->x11disp->remoteauthprotoname,
+                       PKTT_PASSWORD,
+                       PKT_STR, ssh->x11disp->remoteauthdatastring,
+                       PKTT_OTHER,
+                       PKT_END);
        }
        do {
            crReturnV;
@@ -4932,8 +5073,8 @@ static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
        } else {
            while (inlen > 0) {
                int len = min(inlen, 512);
-               send_packet(ssh, SSH1_CMSG_STDIN_DATA, PKTT_DATA,
-                           PKT_INT, len, PKT_DATA, in, len,
+               send_packet(ssh, SSH1_CMSG_STDIN_DATA,
+                           PKT_INT, len,  PKTT_DATA, PKT_DATA, in, len,
                            PKTT_OTHER, PKT_END);
                in += len;
                inlen -= len;
@@ -5148,7 +5289,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
        s->maclist = macs, s->nmacs = lenof(macs);
 
   begin_key_exchange:
-    ssh->pkt_ctx &= ~SSH2_PKTCTX_KEX_MASK;
+    ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
     {
        int i, j, commalist_started;
 
@@ -5597,7 +5738,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
          */
         if (!ssh->kex->pdata) {
             logevent("Doing Diffie-Hellman group exchange");
-            ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
+            ssh->pkt_kctx = SSH2_PKTCTX_DHGEX;
             /*
              * Work out how big a DH group we will need to allow that
              * much data.
@@ -5622,7 +5763,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
             s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
             s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
         } else {
-            ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP;
+            ssh->pkt_kctx = SSH2_PKTCTX_DHGROUP;
             ssh->kex_ctx = dh_setup_group(ssh->kex);
             s->kex_init_value = SSH2_MSG_KEXDH_INIT;
             s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
@@ -5681,7 +5822,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
     } else {
        logeventf(ssh, "Doing RSA key exchange with hash %s",
                  ssh->kex->hash->text_name);
-       ssh->pkt_ctx |= SSH2_PKTCTX_RSAKEX;
+       ssh->pkt_kctx = SSH2_PKTCTX_RSAKEX;
         /*
          * RSA key exchange. First expect a KEXRSA_PUBKEY packet
          * from the server.
@@ -5756,7 +5897,7 @@ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
              */
             s->pktout = ssh2_pkt_init(SSH2_MSG_KEXRSA_SECRET);
             ssh2_pkt_addstring_start(s->pktout);
-            ssh2_pkt_addstring_data(s->pktout, outstr, outstrlen);
+            ssh2_pkt_addstring_data(s->pktout, (char *)outstr, outstrlen);
             ssh2_pkt_send_noqueue(ssh, s->pktout);
 
            hash_string(ssh->kex->hash, ssh->exhash, outstr, outstrlen);
@@ -6083,8 +6224,8 @@ static int ssh2_try_send(struct ssh_channel *c)
            len = c->v.v2.remmaxpkt;
        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);
+       dont_log_data(ssh, pktout, PKTLOG_OMIT);
        ssh2_pkt_addstring_data(pktout, data, len);
        end_log_omission(ssh, pktout);
        ssh2_pkt_send(ssh, pktout);
@@ -6126,9 +6267,25 @@ static void ssh2_try_send_and_unthrottle(struct ssh_channel *c)
 }
 
 /*
+ * Set up most of a new ssh_channel for SSH-2.
+ */
+static void ssh2_channel_init(struct ssh_channel *c)
+{
+    Ssh ssh = c->ssh;
+    c->localid = alloc_channel_id(ssh);
+    c->closes = 0;
+    c->throttling_conn = FALSE;
+    c->v.v2.locwindow = c->v.v2.locmaxwin = c->v.v2.remlocwin =
+       ssh->cfg.ssh_simple ? OUR_V2_BIGWIN : OUR_V2_WINSIZE;
+    c->v.v2.winadj_head = c->v.v2.winadj_tail = NULL;
+    c->v.v2.throttle_state = UNTHROTTLED;
+    bufchain_init(&c->v.v2.outbuffer);
+}
+
+/*
  * Potentially enlarge the window on an SSH-2 channel.
  */
-static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
+static void ssh2_set_window(struct ssh_channel *c, int newwin)
 {
     Ssh ssh = c->ssh;
 
@@ -6141,15 +6298,68 @@ static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
        return;
 
     /*
+     * If the remote end has a habit of ignoring maxpkt, limit the
+     * window so that it has no choice (assuming it doesn't ignore the
+     * window as well).
+     */
+    if ((ssh->remote_bugs & BUG_SSH2_MAXPKT) && newwin > OUR_V2_MAXPKT)
+       newwin = OUR_V2_MAXPKT;
+       
+
+    /*
      * Only send a WINDOW_ADJUST if there's significantly more window
      * available than the other end thinks there is.  This saves us
      * sending a WINDOW_ADJUST for every character in a shell session.
      *
      * "Significant" is arbitrarily defined as half the window size.
      */
-    if (newwin > c->v.v2.locwindow * 2) {
+    if (newwin / 2 >= c->v.v2.locwindow) {
        struct Packet *pktout;
+       struct winadj *wa;
 
+       /*
+        * In order to keep track of how much window the client
+        * actually has available, we'd like it to acknowledge each
+        * WINDOW_ADJUST.  We can't do that directly, so we accompany
+        * it with a CHANNEL_REQUEST that has to be acknowledged.
+        *
+        * This is only necessary if we're opening the window wide.
+        * If we're not, then throughput is being constrained by
+        * something other than the maximum window size anyway.
+        *
+        * We also only send this if the main channel has finished its
+        * initial CHANNEL_REQUESTs and installed the default
+        * CHANNEL_FAILURE handler, so as not to risk giving it
+        * unexpected CHANNEL_FAILUREs.
+        */
+       if (newwin == c->v.v2.locmaxwin &&
+           ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE]) {
+           pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+           ssh2_pkt_adduint32(pktout, c->remoteid);
+           ssh2_pkt_addstring(pktout, "winadj@putty.projects.tartarus.org");
+           ssh2_pkt_addbool(pktout, TRUE);
+           ssh2_pkt_send(ssh, pktout);
+
+           /*
+            * CHANNEL_FAILURE doesn't come with any indication of
+            * what message caused it, so we have to keep track of the
+            * outstanding CHANNEL_REQUESTs ourselves.
+            */
+           wa = snew(struct winadj);
+           wa->size = newwin - c->v.v2.locwindow;
+           wa->next = NULL;
+           if (!c->v.v2.winadj_head)
+               c->v.v2.winadj_head = wa;
+           else
+               c->v.v2.winadj_tail->next = wa;
+           c->v.v2.winadj_tail = wa;
+           if (c->v.v2.throttle_state != UNTHROTTLED)
+               c->v.v2.throttle_state = UNTHROTTLING;
+       } else {
+           /* Pretend the WINDOW_ADJUST was acked immediately. */
+           c->v.v2.remlocwin = newwin;
+           c->v.v2.throttle_state = THROTTLED;
+       }
        pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
        ssh2_pkt_adduint32(pktout, c->remoteid);
        ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow);
@@ -6158,12 +6368,94 @@ static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
     }
 }
 
+/*
+ * Find the channel associated with a message.  If there's no channel,
+ * or it's not properly open, make a noise about it and return NULL.
+ */
+static struct ssh_channel *ssh2_channel_msg(Ssh ssh, struct Packet *pktin)
+{
+    unsigned localid = ssh_pkt_getuint32(pktin);
+    struct ssh_channel *c;
+
+    c = find234(ssh->channels, &localid, ssh_channelfind);
+    if (!c ||
+       (c->halfopen && pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION &&
+        pktin->type != SSH2_MSG_CHANNEL_OPEN_FAILURE)) {
+       char *buf = dupprintf("Received %s for %s channel %u",
+                             ssh2_pkt_type(ssh->pkt_kctx, ssh->pkt_actx,
+                                           pktin->type),
+                             c ? "half-open" : "nonexistent", localid);
+       ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+       sfree(buf);
+       return NULL;
+    }
+    return c;
+}
+
+static void ssh2_msg_channel_success(Ssh ssh, struct Packet *pktin)
+{
+    /*
+     * This should never get called.  All channel requests are either
+     * sent with want_reply false or are sent before this handler gets
+     * installed.
+     */
+    struct ssh_channel *c;
+    struct winadj *wa;
+
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
+    wa = c->v.v2.winadj_head;
+    if (wa)
+       ssh_disconnect(ssh, NULL, "Received SSH_MSG_CHANNEL_SUCCESS for "
+                      "\"winadj@putty.projects.tartarus.org\"",
+                      SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+    else
+       ssh_disconnect(ssh, NULL,
+                      "Received unsolicited SSH_MSG_CHANNEL_SUCCESS",
+                      SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+}
+
+static void ssh2_msg_channel_failure(Ssh ssh, struct Packet *pktin)
+{
+    /*
+     * The only time this should get called is for "winadj@putty"
+     * messages sent above.  All other channel requests are either
+     * sent with want_reply false or are sent before this handler gets
+     * installed.
+     */
+    struct ssh_channel *c;
+    struct winadj *wa;
+
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
+    wa = c->v.v2.winadj_head;
+    if (!wa) {
+       ssh_disconnect(ssh, NULL,
+                      "Received unsolicited SSH_MSG_CHANNEL_FAILURE",
+                      SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
+       return;
+    }
+    c->v.v2.winadj_head = wa->next;
+    c->v.v2.remlocwin += wa->size;
+    sfree(wa);
+    /*
+     * winadj messages are only sent when the window is fully open, so
+     * if we get an ack of one, we know any pending unthrottle is
+     * complete.
+     */
+    if (c->v.v2.throttle_state == UNTHROTTLING)
+       c->v.v2.throttle_state = UNTHROTTLED;
+}
+
 static 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 = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
+    if (!c->closes) {
        c->v.v2.remwindow += ssh_pkt_getuint32(pktin);
        ssh2_try_send_and_unthrottle(c);
     }
@@ -6173,11 +6465,10 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
 {
     char *data;
     int length;
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
     if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
        ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR)
        return;                        /* extended but not stderr */
@@ -6185,6 +6476,7 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
     if (data) {
        int bufsize = 0;
        c->v.v2.locwindow -= length;
+       c->v.v2.remlocwin -= length;
        switch (c->type) {
          case CHAN_MAINSESSION:
            bufsize =
@@ -6242,22 +6534,43 @@ static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin)
            break;
        }
        /*
+        * If it looks like the remote end hit the end of its window,
+        * and we didn't want it to do that, think about using a
+        * larger window.
+        */
+       if (c->v.v2.remlocwin <= 0 && c->v.v2.throttle_state == UNTHROTTLED &&
+           c->v.v2.locmaxwin < 0x40000000)
+           c->v.v2.locmaxwin += OUR_V2_WINSIZE;
+       /*
         * If we are not buffering too much data,
         * enlarge the window again at the remote side.
+        * If we are buffering too much, we may still
+        * need to adjust the window if the server's
+        * sent excess data.
+        */
+       ssh2_set_window(c, bufsize < c->v.v2.locmaxwin ?
+                       c->v.v2.locmaxwin - bufsize : 0);
+       /*
+        * If we're either buffering way too much data, or if we're
+        * buffering anything at all and we're in "simple" mode,
+        * throttle the whole channel.
         */
-       if (bufsize < OUR_V2_WINSIZE)
-           ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
+       if ((bufsize > c->v.v2.locmaxwin ||
+            (ssh->cfg.ssh_simple && bufsize > 0)) &&
+           !c->throttling_conn) {
+           c->throttling_conn = 1;
+           ssh_throttle_conn(ssh, +1);
+       }
     }
 }
 
 static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
 {
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
 
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
 
     if (c->type == CHAN_X11) {
        /*
@@ -6276,16 +6589,12 @@ static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin)
 
 static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
 {
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
     struct Packet *pktout;
 
-    c = find234(ssh->channels, &i, ssh_channelfind);
-    if (!c || c->halfopen) {
-       bombout(("Received CHANNEL_CLOSE for %s channel %d\n",
-                c ? "half-open" : "nonexistent", i));
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
        return;
-    }
     /* Do pre-close processing on the channel. */
     switch (c->type) {
       case CHAN_MAINSESSION:
@@ -6338,13 +6647,12 @@ static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin)
 
 static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin)
 {
-    unsigned i = ssh_pkt_getuint32(pktin);
     struct ssh_channel *c;
     struct Packet *pktout;
 
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
     if (c->type != CHAN_SOCKDATA_DORMANT)
        return;                        /* dunno why they're confirming this */
     c->remoteid = ssh_pkt_getuint32(pktin);
@@ -6376,14 +6684,13 @@ static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
            "Unknown channel type",
            "Resource shortage",
     };
-    unsigned i = ssh_pkt_getuint32(pktin);
     unsigned reason_code;
     char *reason_string;
     int reason_length;
     struct ssh_channel *c;
-    c = find234(ssh->channels, &i, ssh_channelfind);
+    c = ssh2_channel_msg(ssh, pktin);
     if (!c)
-       return;                        /* nonexistent channel */
+       return;
     if (c->type != CHAN_SOCKDATA_DORMANT)
        return;                        /* dunno why they're failing this */
 
@@ -6402,31 +6709,19 @@ static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin)
 
 static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
 {
-    unsigned localid;
     char *type;
     int typelen, want_reply;
     int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */
     struct ssh_channel *c;
     struct Packet *pktout;
 
-    localid = ssh_pkt_getuint32(pktin);
+    c = ssh2_channel_msg(ssh, pktin);
+    if (!c)
+       return;
     ssh_pkt_getstring(pktin, &type, &typelen);
     want_reply = ssh2_pkt_getbool(pktin);
 
     /*
-     * First, check that the channel exists. Otherwise,
-     * we can instantly disconnect with a rude message.
-     */
-    c = find234(ssh->channels, &localid, ssh_channelfind);
-    if (!c) {
-       char *buf = dupprintf("Received channel request for nonexistent"
-                             " channel %d", localid);
-       ssh_disconnect(ssh, NULL, buf, SSH2_DISCONNECT_PROTOCOL_ERROR, FALSE);
-       sfree(buf);
-       return;
-    }
-
-    /*
      * Having got the channel number, we now look at
      * the request type string to see if it's something
      * we recognise.
@@ -6453,7 +6748,7 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
            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
+            * having been a `string' in the drafts of RFC 4254 since at
             * least 2001. (Fixed in session.c 1.147.) Try to
             * infer which we can safely parse it as. */
            {
@@ -6496,7 +6791,7 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin)
                    fmt_sig = dupprintf(" %d", signum);
                    ssh->exitcode = 128 + signum;
                } else {
-                   /* As per the drafts. */
+                   /* As per RFC 4254. */
                    char *sig;
                    int siglen;
                    ssh_pkt_getstring(pktin, &sig, &siglen);
@@ -6647,9 +6942,8 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
 
        if (!ssh->X11_fwd_enabled)
            error = "X11 forwarding is not enabled";
-       else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c,
-                         ssh->x11auth, addrstr, peerport,
-                         &ssh->cfg) != NULL) {
+       else if (x11_init(&c->u.x11.s, ssh->x11disp, c,
+                         addrstr, peerport, &ssh->cfg) != NULL) {
            error = "Unable to open an X11 connection";
        } else {
            logevent("Opening X11 forward connection succeeded");
@@ -6711,12 +7005,9 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin)
        logeventf(ssh, "Rejected channel open: %s", error);
        sfree(c);
     } else {
-       c->localid = alloc_channel_id(ssh);
-       c->closes = 0;
-       c->v.v2.locwindow = OUR_V2_WINSIZE;
+       ssh2_channel_init(c);
        c->v.v2.remwindow = winsize;
        c->v.v2.remmaxpkt = pktsize;
-       bufchain_init(&c->v.v2.outbuffer);
        add234(ssh->channels, c);
        pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
        ssh2_pkt_adduint32(pktout, c->remoteid);
@@ -6775,12 +7066,15 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
                AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
                AUTH_TYPE_PASSWORD,
+               AUTH_TYPE_GSSAPI,
                AUTH_TYPE_KEYBOARD_INTERACTIVE,
                AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
        } type;
        int done_service_req;
        int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
        int tried_pubkey_config, done_agent;
+       int can_gssapi;
+       int tried_gssapi;
        int kbd_inter_refused;
        int we_are_in;
        prompts_t *cur_prompt;
@@ -6804,6 +7098,11 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        int try_send;
        int num_env, env_left, env_ok;
        struct Packet *pktout;
+       Ssh_gss_ctx gss_ctx;
+       Ssh_gss_buf gss_buf;
+       Ssh_gss_buf gss_rcvtok, gss_sndtok;
+       Ssh_gss_name gss_srv_name;
+       Ssh_gss_stat gss_stat;
     };
     crState(do_ssh2_authconn_state);
 
@@ -6811,6 +7110,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
 
     s->done_service_req = FALSE;
     s->we_are_in = FALSE;
+    s->tried_gssapi = FALSE;
+
     if (!ssh->cfg.ssh_no_userauth) {
        /*
         * Request userauth protocol, and await a response to it.
@@ -7037,7 +7338,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
         * just in case it succeeds, and (b) so that we know what
         * authentication methods we can usefully try next.
         */
-       ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
+       ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
 
        s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
        ssh2_pkt_addstring(s->pktout, s->username);
@@ -7098,7 +7399,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                break;
            }
 
-           if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) {
+           if (pktin->type != SSH2_MSG_USERAUTH_FAILURE && s->type != AUTH_TYPE_GSSAPI) {
                bombout(("Strange packet received during authentication: "
                         "type %d", pktin->type));
                crStopV;
@@ -7169,9 +7470,14 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    in_commasep_string("password", methods, methlen);
                s->can_keyb_inter = ssh->cfg.try_ki_auth &&
                    in_commasep_string("keyboard-interactive", methods, methlen);
+#ifndef NO_GSSAPI              
+               s->can_gssapi = ssh->cfg.try_gssapi_auth &&
+                 in_commasep_string("gssapi-with-mic", methods, methlen) &&
+                 ssh_gss_init();
+#endif
            }
 
-           ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
+           ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
 
            if (s->can_pubkey && !s->done_agent && s->nkeys) {
 
@@ -7179,8 +7485,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                 * Attempt public-key authentication using a key from Pageant.
                 */
 
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
+               ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
 
                logeventf(ssh, "Trying Pageant key #%d", s->keyi);
 
@@ -7327,8 +7632,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                struct ssh2_userkey *key;   /* not live over crReturn */
                char *passphrase;           /* not live over crReturn */
 
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
+               ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY;
 
                s->tried_pubkey_config = TRUE;
 
@@ -7499,6 +7803,157 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    key->alg->freekey(key->data);
                }
 
+#ifndef NO_GSSAPI
+           } else if (s->can_gssapi && !s->tried_gssapi) {
+
+               /* GSSAPI Authentication */
+
+               int micoffset;
+               Ssh_gss_buf mic;
+               s->type = AUTH_TYPE_GSSAPI;
+               s->tried_gssapi = TRUE;
+               s->gotit = TRUE;
+               ssh->pkt_actx = SSH2_PKTCTX_GSSAPI;
+
+               /* Sending USERAUTH_REQUEST with "gssapi-with-mic" method */
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+               ssh2_pkt_addstring(s->pktout, s->username);
+               ssh2_pkt_addstring(s->pktout, "ssh-connection");
+               ssh2_pkt_addstring(s->pktout, "gssapi-with-mic");
+
+               /* add mechanism info */
+               ssh_gss_indicate_mech(&s->gss_buf);
+
+               /* number of GSSAPI mechanisms */
+               ssh2_pkt_adduint32(s->pktout,1);
+
+               /* length of OID + 2 */
+               ssh2_pkt_adduint32(s->pktout, s->gss_buf.len + 2);
+               ssh2_pkt_addbyte(s->pktout, SSH2_GSS_OIDTYPE);
+
+               /* length of OID */
+               ssh2_pkt_addbyte(s->pktout, (unsigned char) s->gss_buf.len);
+
+               ssh_pkt_adddata(s->pktout, s->gss_buf.data, s->gss_buf.len);
+               ssh2_pkt_send(ssh, s->pktout);
+               crWaitUntilV(pktin);
+               if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_RESPONSE) {
+                   logevent("GSSAPI authentication request refused");
+                   continue;
+               }
+
+               /* check returned packet ... */
+
+               ssh_pkt_getstring(pktin,&s->gss_rcvtok.data,&s->gss_rcvtok.len);
+               if (s->gss_rcvtok.len != s->gss_buf.len + 2 ||
+                   s->gss_rcvtok.data[0] != SSH2_GSS_OIDTYPE ||
+                   s->gss_rcvtok.data[1] != s->gss_buf.len ||
+                   memcmp(s->gss_rcvtok.data+2,s->gss_buf.data,s->gss_buf.len) ) {
+                   logevent("GSSAPI authentication - wrong response from server");
+                   continue;
+               }
+
+               /* now start running */
+               s->gss_stat = ssh_gss_import_name(ssh->fullhostname,
+                                                 &s->gss_srv_name);
+               if (s->gss_stat != SSH_GSS_OK) {
+                   if (s->gss_stat == SSH_GSS_BAD_HOST_NAME)
+                       logevent("GSSAPI import name failed - Bad service name");
+                   else
+                       logevent("GSSAPI import name failed");
+                   continue;
+               }
+
+               /* fetch TGT into GSS engine */
+               s->gss_stat = ssh_gss_acquire_cred(&s->gss_ctx);
+
+               if (s->gss_stat != SSH_GSS_OK) {
+                   logevent("GSSAPI authentication failed to get credentials");
+                   ssh_gss_release_name(&s->gss_srv_name);
+                   continue;
+               }
+
+               /* initial tokens are empty */
+               s->gss_rcvtok.len = s->gss_sndtok.len = 0;
+               s->gss_rcvtok.data = s->gss_sndtok.data = NULL;
+
+               /* now enter the loop */
+               do {
+                   s->gss_stat = ssh_gss_init_sec_context(&s->gss_ctx,
+                                                          s->gss_srv_name,
+                                                          ssh->cfg.gssapifwd,
+                                                          &s->gss_rcvtok,
+                                                          &s->gss_sndtok);
+
+                   if (s->gss_stat!=SSH_GSS_S_COMPLETE &&
+                       s->gss_stat!=SSH_GSS_S_CONTINUE_NEEDED) {
+                       logevent("GSSAPI authentication initialisation failed");
+
+                       if (ssh_gss_display_status(s->gss_ctx,&s->gss_buf) == SSH_GSS_OK) {
+                           logevent(s->gss_buf.data);
+                           sfree(s->gss_buf.data);
+                       }
+
+                       break;
+                   }
+                   logevent("GSSAPI authentication initialised");
+
+                   /* Client and server now exchange tokens until GSSAPI
+                    * no longer says CONTINUE_NEEDED */
+
+                   if (s->gss_sndtok.len != 0) {
+                       s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
+                       ssh_pkt_addstring_start(s->pktout);
+                       ssh_pkt_addstring_data(s->pktout,s->gss_sndtok.data,s->gss_sndtok.len);
+                       ssh2_pkt_send(ssh, s->pktout);
+                       ssh_gss_free_tok(&s->gss_sndtok);
+                   }
+
+                   if (s->gss_stat == SSH_GSS_S_CONTINUE_NEEDED) {
+                       crWaitUntilV(pktin);
+                       if (pktin->type != SSH2_MSG_USERAUTH_GSSAPI_TOKEN) {
+                           logevent("GSSAPI authentication - bad server response");
+                           s->gss_stat = SSH_GSS_FAILURE;
+                           break;
+                       }
+                       ssh_pkt_getstring(pktin,&s->gss_rcvtok.data,&s->gss_rcvtok.len);
+                   }
+               } while (s-> gss_stat == SSH_GSS_S_CONTINUE_NEEDED);
+
+               if (s->gss_stat != SSH_GSS_OK) {
+                   ssh_gss_release_name(&s->gss_srv_name);
+                   ssh_gss_release_cred(&s->gss_ctx);
+                   continue;
+               }
+               logevent("GSSAPI authentication loop finished OK");
+
+               /* Now send the MIC */
+
+               s->pktout = ssh2_pkt_init(0);
+               micoffset = s->pktout->length;
+               ssh_pkt_addstring_start(s->pktout);
+               ssh_pkt_addstring_data(s->pktout, (char *)ssh->v2_session_id, ssh->v2_session_id_len);
+               ssh_pkt_addbyte(s->pktout, SSH2_MSG_USERAUTH_REQUEST);
+               ssh_pkt_addstring(s->pktout, s->username);
+               ssh_pkt_addstring(s->pktout, "ssh-connection");
+               ssh_pkt_addstring(s->pktout, "gssapi-with-mic");
+
+               s->gss_buf.data = (char *)s->pktout->data + micoffset;
+               s->gss_buf.len = s->pktout->length - micoffset;
+
+               ssh_gss_get_mic(s->gss_ctx, &s->gss_buf, &mic);
+               s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_GSSAPI_MIC);
+               ssh_pkt_addstring_start(s->pktout);
+               ssh_pkt_addstring_data(s->pktout, mic.data, mic.len);
+               ssh2_pkt_send(ssh, s->pktout);
+               ssh_gss_free_mic(&mic);
+
+               s->gotit = FALSE;
+
+               ssh_gss_release_name(&s->gss_srv_name);
+               ssh_gss_release_cred(&s->gss_ctx);
+               continue;
+#endif
            } else if (s->can_keyb_inter && !s->kbd_inter_refused) {
 
                /*
@@ -7507,8 +7962,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
 
                s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
 
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
+               ssh->pkt_actx = SSH2_PKTCTX_KBDINTER;
 
                s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
                ssh2_pkt_addstring(s->pktout, s->username);
@@ -7571,7 +8025,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    s->cur_prompt->instr_reqd = TRUE;
 
                    /*
-                    * Get the prompts from the packet.
+                    * Get any prompt(s) from the packet.
                     */
                    s->num_prompts = ssh_pkt_getuint32(pktin);
                    for (i = 0; i < s->num_prompts; i++) {
@@ -7593,9 +8047,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    }
 
                    /*
-                    * Get the user's responses.
+                     * Display any instructions, and get the user's
+                     * response(s).
                     */
-                   if (s->num_prompts) {
+                   {
                        int ret; /* not live over crReturn */
                        ret = get_userpass_input(s->cur_prompt, NULL, 0);
                        while (ret < 0) {
@@ -7617,7 +8072,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                    }
 
                    /*
-                    * Send the responses to the server.
+                    * Send the response(s) to the server.
                     */
                    s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
                    ssh2_pkt_adduint32(s->pktout, s->num_prompts);
@@ -7650,8 +8105,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
                int ret; /* not live over crReturn */
                int changereq_first_time; /* not live over crReturn */
 
-               ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
-               ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
+               ssh->pkt_actx = SSH2_PKTCTX_PASSWORD;
 
                s->cur_prompt = new_prompts(ssh->frontend);
                s->cur_prompt->to_server = TRUE;
@@ -7921,14 +8375,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
         */
        ssh->mainchan = snew(struct ssh_channel);
        ssh->mainchan->ssh = ssh;
-       ssh->mainchan->localid = alloc_channel_id(ssh);
+       ssh2_channel_init(ssh->mainchan);
        logeventf(ssh,
                  "Opening direct-tcpip channel to %s:%d in place of session",
                  ssh->cfg.ssh_nc_host, ssh->cfg.ssh_nc_port);
        s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
        ssh2_pkt_addstring(s->pktout, "direct-tcpip");
        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, OUR_V2_MAXPKT);      /* our max pkt size */
        ssh2_pkt_addstring(s->pktout, ssh->cfg.ssh_nc_host);
@@ -7955,10 +8408,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
        ssh->mainchan->halfopen = FALSE;
        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 direct-tcpip channel");
@@ -7966,11 +8417,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     } else {
        ssh->mainchan = snew(struct ssh_channel);
        ssh->mainchan->ssh = ssh;
-       ssh->mainchan->localid = alloc_channel_id(ssh);
+       ssh2_channel_init(ssh->mainchan);
        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, OUR_V2_MAXPKT);    /* our max pkt size */
        ssh2_pkt_send(ssh, s->pktout);
@@ -7987,10 +8437,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin);
        ssh->mainchan->halfopen = FALSE;
        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");
@@ -8015,21 +8463,33 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
     ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] =
        ssh2_msg_channel_open;
 
+    if (ssh->cfg.ssh_simple) {
+       /*
+        * This message indicates to the server that we promise
+        * not to try to run any other channel in parallel with
+        * this one, so it's safe for it to advertise a very large
+        * window and leave the flow control to TCP.
+        */
+       s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+       ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid);
+       ssh2_pkt_addstring(s->pktout, "simple@putty.projects.tartarus.org");
+       ssh2_pkt_addbool(s->pktout, 0); /* no reply */
+       ssh2_pkt_send(ssh, s->pktout);
+    }
+
     /*
      * Potentially enable X11 forwarding.
      */
     if (ssh->mainchan && !ssh->ncmode && 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);
+       ssh->x11disp = x11_setup_display(ssh->cfg.x11_display,
+                                        ssh->cfg.x11_auth, &ssh->cfg);
        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, ssh->x11disp->remoteauthprotoname);
        /*
         * Note that while we blank the X authentication data here, we don't
         * take any special action to blank the start of an X11 channel,
@@ -8038,9 +8498,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
         * cookie into the log.
         */
        dont_log_password(ssh, s->pktout, PKTLOG_BLANK);
-       ssh2_pkt_addstring(s->pktout, data);
+       ssh2_pkt_addstring(s->pktout, ssh->x11disp->remoteauthdatastring);
        end_log_omission(ssh, s->pktout);
-       ssh2_pkt_adduint32(s->pktout, x11_get_screen_number(ssh->cfg.x11_display));
+       ssh2_pkt_adduint32(s->pktout, ssh->x11disp->screennum);
        ssh2_pkt_send(ssh, s->pktout);
 
        crWaitUntilV(pktin);
@@ -8270,6 +8730,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen,
        ssh_special(ssh, TS_EOF);
 
     /*
+     * All the initial channel requests are done, so install the default
+     * failure handler.
+     */
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = ssh2_msg_channel_success;
+    ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = ssh2_msg_channel_failure;
+
+    /*
      * Transfer data!
      */
     if (ssh->ldisc)
@@ -8317,7 +8784,7 @@ static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
 {
     /* log reason code in disconnect message */
     char *buf, *msg;
-    int nowlen, reason, msglen;
+    int reason, msglen;
 
     reason = ssh_pkt_getuint32(pktin);
     ssh_pkt_getstring(pktin, &msg, &msglen);
@@ -8331,14 +8798,14 @@ static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin)
     }
     logevent(buf);
     sfree(buf);
-    buf = dupprintf("Disconnection message text: %n%.*s",
-                   &nowlen, msglen, msg);
+    buf = dupprintf("Disconnection message text: %.*s",
+                   msglen, msg);
     logevent(buf);
-    bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
+    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));
+            msglen, msg));
     sfree(buf);
 }
 
@@ -8522,8 +8989,9 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->deferred_len = 0;
     ssh->deferred_size = 0;
     ssh->fallback_cmd = 0;
-    ssh->pkt_ctx = 0;
-    ssh->x11auth = NULL;
+    ssh->pkt_kctx = SSH2_PKTCTX_NOKEX;
+    ssh->pkt_actx = SSH2_PKTCTX_NOAUTH;
+    ssh->x11disp = NULL;
     ssh->v1_compressing = FALSE;
     ssh->v2_outgoing_sequence = 0;
     ssh->ssh1_rdpkt_crstate = 0;
@@ -8569,7 +9037,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh->send_ok = 0;
     ssh->editing = 0;
     ssh->echoing = 0;
-    ssh->v1_throttle_count = 0;
+    ssh->conn_throttle_count = 0;
     ssh->overall_bufsize = 0;
     ssh->fallback_cmd = 0;
 
@@ -8661,14 +9129,15 @@ static void ssh_free(void *handle)
        ssh->rportfwds = NULL;
     }
     sfree(ssh->deferred_send_data);
-    if (ssh->x11auth)
-       x11_free_auth(ssh->x11auth);
+    if (ssh->x11disp)
+       x11_free_display(ssh->x11disp);
     sfree(ssh->do_ssh_init_state);
     sfree(ssh->do_ssh1_login_state);
     sfree(ssh->do_ssh2_transport_state);
     sfree(ssh->do_ssh2_authconn_state);
     sfree(ssh->v_c);
     sfree(ssh->v_s);
+    sfree(ssh->fullhostname);
     if (ssh->crcda_ctx) {
        crcda_free_context(ssh->crcda_ctx);
        ssh->crcda_ctx = NULL;
@@ -8846,7 +9315,7 @@ static const struct telnet_special *ssh_get_specials(void *handle)
     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-23.
+       /* These are the signal names defined by RFC 4254.
         * They include all the ISO C signals, but are a subset of the POSIX
         * required signals. */
        {"SIGINT (Interrupt)", TS_SIGINT},
@@ -8995,17 +9464,13 @@ void *new_sock_channel(void *handle, Socket s)
     Ssh ssh = (Ssh) handle;
     struct ssh_channel *c;
     c = snew(struct ssh_channel);
-    c->ssh = ssh;
 
-    if (c) {
-       c->halfopen = TRUE;
-       c->localid = alloc_channel_id(ssh);
-       c->closes = 0;
-       c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
-       c->u.pfd.s = s;
-       bufchain_init(&c->v.v2.outbuffer);
-       add234(ssh->channels, c);
-    }
+    c->ssh = ssh;
+    ssh2_channel_init(c);
+    c->halfopen = TRUE;
+    c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
+    c->u.pfd.s = s;
+    add234(ssh->channels, c);
     return c;
 }
 
@@ -9016,13 +9481,27 @@ void *new_sock_channel(void *handle, Socket s)
 static void ssh_unthrottle(void *handle, int bufsize)
 {
     Ssh ssh = (Ssh) handle;
+    int buflimit;
+
     if (ssh->version == 1) {
        if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
            ssh->v1_stdout_throttling = 0;
-           ssh1_throttle(ssh, -1);
+           ssh_throttle_conn(ssh, -1);
        }
     } else {
-       ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
+       if (ssh->mainchan) {
+           ssh2_set_window(ssh->mainchan,
+                           bufsize < ssh->mainchan->v.v2.locmaxwin ?
+                           ssh->mainchan->v.v2.locmaxwin - bufsize : 0);
+           if (ssh->cfg.ssh_simple)
+               buflimit = 0;
+           else
+               buflimit = ssh->mainchan->v.v2.locmaxwin;
+           if (ssh->mainchan->throttling_conn && bufsize <= buflimit) {
+               ssh->mainchan->throttling_conn = 0;
+               ssh_throttle_conn(ssh, -1);
+           }
+       }
     }
 }
 
@@ -9045,7 +9524,6 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
        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(pktout, c->v.v2.locwindow);/* our window size */
        ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT);      /* our max pkt size */
        ssh2_pkt_addstring(pktout, hostname);
@@ -9146,5 +9624,7 @@ Backend ssh_backend = {
     ssh_provide_logctx,
     ssh_unthrottle,
     ssh_cfg_info,
+    "ssh",
+    PROT_SSH,
     22
 };