ctrl_droplist(s, "Chokes on SSH-2 ignore messages", '2', 20,
HELPCTX(ssh_bugs_ignore2),
sshbug_handler, I(CONF_sshbug_ignore2));
+ ctrl_droplist(s, "Chokes on PuTTY's SSH-2 'winadj' requests", 'j',
+ 20, HELPCTX(ssh_bugs_winadj),
+ sshbug_handler, I(CONF_sshbug_winadj));
ctrl_droplist(s, "Miscomputes SSH-2 HMAC keys", 'm', 20,
HELPCTX(ssh_bugs_hmac2),
sshbug_handler, I(CONF_sshbug_hmac2));
correct server, the session will work correctly, but download
performance will be less than it could be.
+\S{config-ssh-bug-winadj} \q{Chokes on PuTTY's SSH-2 \cq{winadj} requests}
+
+\cfg{winhelp-topic}{ssh.bugs.winadj}
+
+PuTTY sometimes sends a special request to SSH servers in the middle
+of channel data, with the name \cw{winadj@putty.projects.tartarus.org}
+(see \k{sshnames-channel}). The purpose of this request is to measure
+the round-trip time to the server, which PuTTY uses to tune its flow
+control. The server does not actually have to \e{understand} the
+message; it is expected to send back a \cw{SSH_MSG_CHANNEL_FAILURE}
+message indicating that it didn't understand it. (All PuTTY needs for
+its timing calculations is \e{some} kind of response.)
+
+It has been known for some SSH servers to get confused by this message
+in one way or another \dash because it has a long name, or because
+they can't cope with unrecognised request names even to the extent of
+sending back the correct failure response, or because they handle it
+sensibly but fill up the server's log file with pointless spam, or
+whatever. PuTTY therefore supports this bug-compatibility flag: if it
+believes the server has this bug, it will never send its
+\cq{winadj@putty.projects.tartarus.org} request, and will make do
+without its timing data.
+
\H{config-serial} The Serial panel
The \i{Serial} panel allows you to configure options that only apply
X(INT, NONE, sshbug_rekey2) \
X(INT, NONE, sshbug_maxpkt2) \
X(INT, NONE, sshbug_ignore2) \
+ X(INT, NONE, sshbug_winadj) \
/* \
* ssh_simple means that we promise never to open any channel \
* other than the main one, which means it can safely use a very \
write_setting_i(sesskey, "BugPKSessID2", 2-conf_get_int(conf, CONF_sshbug_pksessid2));
write_setting_i(sesskey, "BugRekey2", 2-conf_get_int(conf, CONF_sshbug_rekey2));
write_setting_i(sesskey, "BugMaxPkt2", 2-conf_get_int(conf, CONF_sshbug_maxpkt2));
+ write_setting_i(sesskey, "BugWinadj", 2-conf_get_int(conf, CONF_sshbug_winadj));
write_setting_i(sesskey, "StampUtmp", conf_get_int(conf, CONF_stamp_utmp));
write_setting_i(sesskey, "LoginShell", conf_get_int(conf, CONF_login_shell));
write_setting_i(sesskey, "ScrollbarOnLeft", conf_get_int(conf, CONF_scrollbar_on_left));
i = gppi_raw(sesskey, "BugPKSessID2", 0); conf_set_int(conf, CONF_sshbug_pksessid2, 2-i);
i = gppi_raw(sesskey, "BugRekey2", 0); conf_set_int(conf, CONF_sshbug_rekey2, 2-i);
i = gppi_raw(sesskey, "BugMaxPkt2", 0); conf_set_int(conf, CONF_sshbug_maxpkt2, 2-i);
+ i = gppi_raw(sesskey, "BugWinadj", 0); conf_set_int(conf, CONF_sshbug_winadj, 2-i);
conf_set_int(conf, CONF_ssh_simple, FALSE);
gppi(sesskey, "StampUtmp", 1, conf, CONF_stamp_utmp);
gppi(sesskey, "LoginShell", 1, conf, CONF_login_shell);
#define BUG_SSH2_PK_SESSIONID 128
#define BUG_SSH2_MAXPKT 256
#define BUG_CHOKES_ON_SSH2_IGNORE 512
+#define BUG_CHOKES_ON_WINADJ 1024
/*
* Codes for terminal modes.
ssh->remote_bugs |= BUG_CHOKES_ON_SSH2_IGNORE;
logevent("We believe remote version has SSH-2 ignore bug");
}
+
+ if (conf_get_int(ssh->conf, CONF_sshbug_winadj) == FORCE_ON) {
+ /*
+ * Servers that don't support our winadj request for one
+ * reason or another. Currently, none detected automatically.
+ */
+ ssh->remote_bugs |= BUG_CHOKES_ON_WINADJ;
+ logevent("We believe remote version has winadj bug");
+ }
}
/*
* unexpected CHANNEL_FAILUREs.
*/
if (newwin == c->v.v2.locmaxwin &&
- ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE]) {
+ ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] &&
+ !(ssh->remote_bugs & BUG_CHOKES_ON_WINADJ)) {
pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(pktout, c->remoteid);
ssh2_pkt_addstring(pktout, "winadj@putty.projects.tartarus.org");
#define WINHELP_CTX_ssh_bugs_pksessid2 "ssh.bugs.pksessid2:config-ssh-bug-pksessid2"
#define WINHELP_CTX_ssh_bugs_rekey2 "ssh.bugs.rekey2:config-ssh-bug-rekey"
#define WINHELP_CTX_ssh_bugs_maxpkt2 "ssh.bugs.maxpkt2:config-ssh-bug-maxpkt2"
+#define WINHELP_CTX_ssh_bugs_winadj "ssh.bugs.winadj:config-ssh-bug-winadj"
#define WINHELP_CTX_serial_line "serial.line:config-serial-line"
#define WINHELP_CTX_serial_speed "serial.speed:config-serial-speed"
#define WINHELP_CTX_serial_databits "serial.databits:config-serial-databits"