Hi,
The firewall at work doesn't allow me to make a direct SSH connection
to the Internet, so I use the ProxyCommand to tunnel SSH through a
HTTP proxy. This works fine, except for the fact that the HTTP proxy
server closes the connection after 60 seconds of inactivity. Attached
below is a patch that implements a new configuration option called
"Idle" that lets you specify the maximum idle time of a connection in
seconds. When this limit is reached, a dummy packet (SSH_MSG_IGNORE)
is sent, to fake activity, and to prevent the timeout. This option
might be usefull for others, so I'm posting it here.
--
Dick Streefland //// De Bilt
dick.streefland at xs4all.nl (@ @) The Netherlands
------------------------------oOO--(_)--OOo------------------
--- openssh-2.9.9p2/clientloop.c.orig Tue Sep 18 07:51:14 2001
+++ openssh-2.9.9p2/clientloop.c Thu Oct 11 22:03:09 2001
@@ -320,6 +320,9 @@
client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
int *maxfdp, int *nallocp, int rekeying)
{
+ struct timeval tv;
+ int n;
+
/* Add any selections by the channel mechanism. */
channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying);
@@ -364,7 +367,24 @@
* SSH_MSG_IGNORE packet when the timeout expires.
*/
- if (select((*maxfdp)+1, *readsetp, *writesetp, NULL, NULL) < 0) {
+ /*
+ * When the "Idle" option is set to a non-zero value, a dummy
+ * packet is sent after the connection is idle for the specified
+ * number of seconds, to prevent the connection from timing out.
+ */
+ if (options.idle > 0) {
+ tv.tv_sec = options.idle;
+ tv.tv_usec = 0;
+ n = select((*maxfdp)+1, *readsetp, *writesetp, NULL, &tv);
+ if (n == 0) {
+ debug2("idle");
+ packet_send_ignore(1);
+ packet_send();
+ }
+ } else {
+ n = select((*maxfdp)+1, *readsetp, *writesetp, NULL, NULL);
+ }
+ if (n < 0) {
char buf[100];
/*
--- openssh-2.9.9p2/readconf.c.orig Thu Sep 20 02:57:56 2001
+++ openssh-2.9.9p2/readconf.c Thu Oct 11 22:03:09 2001
@@ -109,7 +109,7 @@
oUser, oHost, oEscapeChar, oRhostsRSAAuthentication, oProxyCommand,
oGlobalKnownHostsFile, oUserKnownHostsFile, oConnectionAttempts,
oBatchMode, oCheckHostIP, oStrictHostKeyChecking, oCompression,
- oCompressionLevel, oKeepAlives, oNumberOfPasswordPrompts,
+ oCompressionLevel, oKeepAlives, oIdle, oNumberOfPasswordPrompts,
oUsePrivilegedPort, oLogLevel, oCiphers, oProtocol, oMacs,
oGlobalKnownHostsFile2, oUserKnownHostsFile2, oPubkeyAuthentication,
oKbdInteractiveAuthentication, oKbdInteractiveDevices, oHostKeyAlias,
@@ -178,6 +178,7 @@
{ "compression", oCompression },
{ "compressionlevel", oCompressionLevel },
{ "keepalive", oKeepAlives },
+ { "idle", oIdle },
{ "numberofpasswordprompts", oNumberOfPasswordPrompts },
{ "loglevel", oLogLevel },
{ "dynamicforward", oDynamicForward },
@@ -415,6 +416,10 @@
intptr = &options->keepalives;
goto parse_flag;
+ case oIdle:
+ intptr = &options->idle;
+ goto parse_int;
+
case oNumberOfPasswordPrompts:
intptr = &options->number_of_password_prompts;
goto parse_int;
@@ -767,6 +772,7 @@
options->strict_host_key_checking = -1;
options->compression = -1;
options->keepalives = -1;
+ options->idle = -1;
options->compression_level = -1;
options->port = -1;
options->connection_attempts = -1;
@@ -859,6 +865,8 @@
options->compression = 0;
if (options->keepalives == -1)
options->keepalives = 1;
+ if (options->idle == -1)
+ options->idle = 0;
if (options->compression_level == -1)
options->compression_level = 6;
if (options->port == -1)
--- openssh-2.9.9p2/readconf.h.orig Thu Sep 20 02:57:56 2001
+++ openssh-2.9.9p2/readconf.h Thu Oct 11 22:03:09 2001
@@ -63,6 +63,7 @@
int compression_level; /* Compression level 1 (fast) to 9
* (best). */
int keepalives; /* Set SO_KEEPALIVE. */
+ int idle; /* prevent idle connection from timing out */
LogLevel log_level; /* Level for logging. */
int port; /* Port to connect. */
--- openssh-2.9.9p2/ssh.1.orig Thu Sep 20 02:57:56 2001
+++ openssh-2.9.9p2/ssh.1 Thu Oct 11 22:03:09 2001
@@ -926,6 +926,14 @@
It is possible to have
multiple identity files specified in configuration files; all these
identities will be tried in sequence.
+.It Cm Idle
+When this option is set to a non-zero value, a dummy packet is sent
+after the connection is idle for the specified number of seconds.
+This faked activity will prevent the connection from timing out.
+The default value is 0 seconds, which disables this feature.
+Note that this is different from the
+.Cm KeepAlive
+option, which merely sets the SO_KEEPALIVE socket option.
.It Cm KeepAlive
Specifies whether the system should send keepalive messages to the
other side.
