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From cbbc8577950b93090171c7394bcdeb68b7c3cd0c Mon Sep 17 00:00:00 2001
From: Colin Watson <cjwatson@debian.org>
Date: Sun, 9 Feb 2014 16:09:51 +0000
Subject: Partial server keep-alive implementation for SSH1
Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1712
Last-Update: 2013-09-14
Patch-Name: ssh1-keepalive.patch
---
clientloop.c | 25 +++++++++++++++----------
ssh_config.5 | 5 ++++-
2 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/clientloop.c b/clientloop.c
index f9175e3..046ca8b 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -563,16 +563,21 @@ client_global_request_reply(int type, u_int32_t seq, void *ctxt)
static void
server_alive_check(void)
{
- if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
- logit("Timeout, server %s not responding.", host);
- cleanup_exit(255);
+ if (compat20) {
+ if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
+ logit("Timeout, server %s not responding.", host);
+ 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);
}
/*
@@ -634,7 +639,7 @@ client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
*/
timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */
- if (options.server_alive_interval > 0 && compat20) {
+ if (options.server_alive_interval > 0) {
timeout_secs = options.server_alive_interval;
server_alive_time = now + options.server_alive_interval;
}
diff --git a/ssh_config.5 b/ssh_config.5
index e6649ac..01f1f7f 100644
--- a/ssh_config.5
+++ b/ssh_config.5
@@ -1325,7 +1325,10 @@ If, for example,
.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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