[PATCH] fix IDLE_WAIT handling

[James Cameron-2]

By Michael Douglass <mikedoug@...>
Signed-off-by: James Cameron <james.cameron@...>

I noticed that my pptpd processes were not terminating when the remote
pptp client went off the network unexpectedly.  I straced the pptpd
process and noticed that the select() loop in pptctrl.c was never timing
out because the /dev/ptmx descriptor was sending data to pptpd every 10
seconds.  Since the select() loop was never timing out, the IDLE_WAIT
mechanism never triggered.

The patch below makes the following changes:

* select() returning 0 is no longer a direct trigger case for sending an
ECHO REQ

* Track the last time we heard anything from our TCP socket in last_time
(initialized to now on startup)

* Any time we go through the loop and we don't hear from our TCP socket,
we check to see if our last_time is older than IDLE_WAIT -- if so,
send an ECHO REQ

I've tested this successfully with my installation.

Index: pptpctrl.c
===================================================================
RCS file: /cvsroot/poptop/poptop/pptpctrl.c,v
retrieving revision 1.21
diff -u -u -r1.21 pptpctrl.c
--- pptpctrl.c 7 Oct 2008 23:17:38 -0000 1.21
+++ pptpctrl.c 15 Jun 2009 02:43:49 -0000
@@ -226,6 +226,7 @@
  int echo_wait = FALSE; /* Waiting for echo? */
  u_int32_t echo_count = 0; /* Sequence # of echo */
  time_t echo_time = 0; /* Time last echo req sent */
+ time_t last_time = time(NULL); /* Time last received data */
  struct timeval idleTime; /* How long to select() */
 
  /* General local variables */
@@ -281,16 +282,6 @@
  } else if (encaps_gre(-1, NULL, 0))
  /* Pending ack and nothing else to do */
  encaps_gre(gre_fd, NULL, 0); /* send ack with no payload */
- else if (echo_wait != TRUE) {
- /* Timeout. Start idle link detection. */
- echo_count++;
- if (pptpctrl_debug)
- syslog(LOG_DEBUG, "CTRL: Sending ECHO REQ id %d", echo_count);
- time(&echo_time);
- make_echo_req_packet(rply_packet, &rply_size, echo_count);
- echo_wait = TRUE;
- send_packet = TRUE;
- }
  break;
 
  default:
@@ -328,6 +319,7 @@
  /* handle control messages */
 
  if (FD_ISSET(clientSocket, &fds)) {
+ time(&last_time);
  send_packet = TRUE;
  switch (read_pptp_packet(clientSocket, packet, rply_packet, &rply_size)) {
  case 0:
@@ -420,6 +412,15 @@
 
  /* Otherwise, the already-formed reply will do fine, so send it */
  }
+ /* send echo request packet if we have not heard from the TCP socket in IDLE_TIME */
+ } else if (echo_wait != TRUE && (time(NULL) - last_time) > IDLE_WAIT) {
+ echo_count++;
+ if (pptpctrl_debug)
+ syslog(LOG_DEBUG, "CTRL: Sending ECHO REQ id %d", echo_count);
+ time(&echo_time);
+ make_echo_req_packet(rply_packet, &rply_size, echo_count);
+ echo_wait = TRUE;
+ send_packet = TRUE;
  }
 
  /* send reply packet - this may block, but it should be very rare */

--
James Cameron                         http://quozl.netrek.org/
HP Open Source, Volunteer             http://opensource.hp.com/
PPTP Client Project, Release Engineer http://pptpclient.sourceforge.net/

------------------------------------------------------------------------------
Crystal Reports - New Free Runtime and 30 Day Trial
Check out the new simplified licensing option that enables unlimited
royalty-free distribution of the report engine for externally facing
server and web deployment.
http://p.sf.net/sfu/businessobjects
_______________________________________________
Poptop-server mailing list
Poptop-server@...
https://lists.sourceforge.net/lists/listinfo/poptop-server