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-rw-r--r--serverloop.c64
1 files changed, 60 insertions, 4 deletions
diff --git a/serverloop.c b/serverloop.c
index d6b360d9..5a5b1e37 100644
--- a/serverloop.c
+++ b/serverloop.c
@@ -35,7 +35,7 @@
*/
#include "includes.h"
-RCSID("$OpenBSD: serverloop.c,v 1.60 2001/04/05 23:39:20 markus Exp $");
+RCSID("$OpenBSD: serverloop.c,v 1.61 2001/04/13 22:46:54 beck Exp $");
#include "xmalloc.h"
#include "packet.h"
@@ -91,6 +91,8 @@ static volatile int child_wait_status; /* Status from wait(). */
void server_init_dispatch(void);
+int client_alive_timeouts = 0;
+
void
sigchld_handler(int sig)
{
@@ -190,6 +192,21 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
{
struct timeval tv, *tvp;
int ret;
+ int client_alive_scheduled = 0;
+
+ /*
+ * if using client_alive, set the max timeout accordingly,
+ * and indicate that this particular timeout was for client
+ * alive by setting the client_alive_scheduled flag.
+ *
+ * this could be randomized somewhat to make traffic
+ * analysis more difficult, but we're not doing it yet.
+ */
+ if (max_time_milliseconds == 0 && options.client_alive_interval) {
+ client_alive_scheduled = 1;
+ max_time_milliseconds = options.client_alive_interval * 1000;
+ } else
+ client_alive_scheduled = 0;
/* When select fails we restart from here. */
retry_select:
@@ -239,7 +256,7 @@ retry_select:
* from it, then read as much as is available and exit.
*/
if (child_terminated && packet_not_very_much_data_to_write())
- if (max_time_milliseconds == 0)
+ if (max_time_milliseconds == 0 || client_alive_scheduled)
max_time_milliseconds = 100;
if (max_time_milliseconds == 0)
@@ -255,12 +272,36 @@ retry_select:
/* Wait for something to happen, or the timeout to expire. */
ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
- if (ret < 0) {
+ if (ret == -1) {
if (errno != EINTR)
error("select: %.100s", strerror(errno));
else
goto retry_select;
}
+ if (ret == 0 && client_alive_scheduled) {
+ /* timeout, check to see how many we have had */
+ client_alive_timeouts++;
+
+ if (client_alive_timeouts > options.client_alive_count_max ) {
+ packet_disconnect(
+ "Timeout, your session not responding.");
+ } else {
+ /*
+ * send a bogus channel request with "wantreply"
+ * we should get back a failure
+ */
+ int id;
+
+ id = channel_find_open();
+ if (id != -1) {
+ channel_request_start(id,
+ "keepalive@openssh.com", 1);
+ packet_send();
+ } else
+ packet_disconnect(
+ "No open channels after timeout!");
+ }
+ }
}
/*
@@ -701,6 +742,19 @@ server_loop2(void)
}
void
+server_input_channel_failure(int type, int plen, void *ctxt)
+{
+ debug("Got CHANNEL_FAILURE for keepalive");
+ /*
+ * reset timeout, since we got a sane answer from the client.
+ * even if this was generated by something other than
+ * the bogus CHANNEL_REQUEST we send for keepalives.
+ */
+ client_alive_timeouts = 0;
+}
+
+
+void
server_input_stdin_data(int type, int plen, void *ctxt)
{
char *data;
@@ -912,7 +966,8 @@ server_init_dispatch_20(void)
dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &channel_input_channel_request);
dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
-
+ /* client_alive */
+ dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_channel_failure);
/* rekeying */
dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
}
@@ -949,3 +1004,4 @@ server_init_dispatch(void)
else
server_init_dispatch_15();
}
+