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Description: Partial server keep-alive implementation for SSH1
Author: Colin Watson <cjwatson@debian.org>
Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1712
Last-Update: 2010-02-27
Index: b/clientloop.c
===================================================================
--- a/clientloop.c
+++ b/clientloop.c
@@ -502,16 +502,21 @@
static void
server_alive_check(void)
{
- if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
- logit("Timeout, server not responding.");
- cleanup_exit(255);
+ if (compat20) {
+ if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
+ logit("Timeout, server not responding.");
+ cleanup_exit(255);
+ }
+ packet_start(SSH2_MSG_GLOBAL_REQUEST);
+ packet_put_cstring("keepalive@openssh.com");
+ packet_put_char(1); /* boolean: want reply */
+ packet_send();
+ /* Insert an empty placeholder to maintain ordering */
+ client_register_global_confirm(NULL, NULL);
+ } else {
+ packet_send_ignore(0);
+ packet_send();
}
- packet_start(SSH2_MSG_GLOBAL_REQUEST);
- packet_put_cstring("keepalive@openssh.com");
- packet_put_char(1); /* boolean: want reply */
- packet_send();
- /* Insert an empty placeholder to maintain ordering */
- client_register_global_confirm(NULL, NULL);
}
/*
@@ -572,7 +577,7 @@
* event pending.
*/
- if (options.server_alive_interval == 0 || !compat20)
+ if (options.server_alive_interval == 0)
tvp = NULL;
else {
tv.tv_sec = options.server_alive_interval;
Index: b/ssh_config.5
===================================================================
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -935,7 +935,10 @@
.Cm ServerAliveCountMax
is left at the default, if the server becomes unresponsive,
ssh will disconnect after approximately 45 seconds.
-This option applies to protocol version 2 only.
+This option applies to protocol version 2 only; in protocol version
+1 there is no mechanism to request a response from the server to the
+server alive messages, so disconnection is the responsibility of the TCP
+stack.
.It Cm ServerAliveInterval
Sets a timeout interval in seconds after which if no data has been received
from the server,
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