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authorrussell <russell@f38db490-d61c-443f-a65b-d21fe96a405b>2008-05-08 19:15:25 +0000
committerrussell <russell@f38db490-d61c-443f-a65b-d21fe96a405b>2008-05-08 19:15:25 +0000
commit7b35d3cf7448b3d37e28e33e0295f7c2aa02c5ff (patch)
treec8ced2a9cc51fe1909b27be0d6e732e0089c0c67
parentba69481b61a4ee1af01f82464fc98fc611ec072a (diff)
Merged revisions 115564 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.2 ........ r115564 | russell | 2008-05-08 14:14:04 -0500 (Thu, 08 May 2008) | 25 lines Fix a race condition that bbryant just found while doing some IAX2 testing. He was running Asterisk trunk running IAX2 calls through a few Asterisk boxes, however, the audio was extremely choppy. We looked at a packet trace and saw a storm of INVAL and VNAK frames being sent from one box to another. It turned out that what had happened was that one box tried to send a CONTROL frame before the 3 way handshake had completed. So, that frame did not include the destination call number, because it didn't have it yet. Part of our recent work for security issues included an additional check to ensure that frames that are supposed to include the destination call number have the correct one. This caused the frame to be rejected with an INVAL. The frame would get retransmitted for forever, rejected every time ... This race condition exists in all versions that got the security changes, in theory. However, it is really only likely that this would cause a problem in Asterisk trunk. There was a control frame being sent (SRCUPDATE) at the _very_ beginning of the call, which does not exist in 1.2 or 1.4. However, I am fixing all versions that could potentially be affected by the introduced race condition. These changes are what bbryant and I came up with to fix the issue. Instead of simply dropping control frames that get sent before the handshake is complete, the code attempts to wait a little while, since in most cases, the handshake will complete very quickly. If it doesn't complete after yielding for a little while, then the frame gets dropped. ........ git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@115565 f38db490-d61c-443f-a65b-d21fe96a405b
-rw-r--r--channels/chan_iax2.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index 8c81ca73d..26f01a38b 100644
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -3633,6 +3633,24 @@ static int iax2_indicate(struct ast_channel *c, int condition, const void *data,
ast_mutex_lock(&iaxsl[callno]);
pvt = iaxs[callno];
+ if (!pvt->peercallno) {
+ /* We don't know the remote side's call number, yet. :( */
+ int count = 10;
+ while (count-- && pvt && !pvt->peercallno) {
+ ast_mutex_unlock(&iaxsl[callno]);
+ usleep(1);
+ ast_mutex_lock(&iaxsl[callno]);
+ pvt = iaxs[callno];
+ }
+ if (pvt->peercallno) {
+ ast_log(LOG_NOTICE, "Yay, we didn't know the peercallno, but we were patient and got it.\n");
+ } else {
+ ast_log(LOG_NOTICE, "Damnit! We waited around and never got the peercallno ...\n");
+ res = -1;
+ goto done;
+ }
+ }
+
switch (condition) {
case AST_CONTROL_HOLD:
if (strcasecmp(pvt->mohinterpret, "passthrough")) {