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Accept T.38 re-INVITE responses with invalid SDP versions. 

This commit changes the 'incoming SDP version' check logic a bit more; when
'ignoresdpversion' is *not* set for a peer, if we initiate a re-INVITE to
switch to T.38, we'll always accept the peer's SDP response, even if they
don't properly increment the SDP version number as they should. If this situation
occurs, a warning message will be generated suggesting that the peer's
configuration be changed to include the 'ignoresdpversion' configuration option
(although ideally they'd fix their SIP implementation to be RFC compliant).

AST-221


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@200689 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Kevin P. Fleming 2009-06-15 20:42:38 +00:00
parent aaeec3b40f
commit 85e57521ab
1 changed files with 31 additions and 8 deletions
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39
channels/chan_sip.c
View File

@ -7824,16 +7824,39 @@ static int process_sdp(struct sip_pvt *p, struct sip_request *req, int t38action
return -1;
}
if (ast_test_flag(&p->flags[1], SIP_PAGE2_IGNORESDPVERSION)
|| p->sessionversion_remote < 0
|| p->sessionversion_remote != rua_version) {
/* we need to check the SDP version number the other end sent us;
* our rules for deciding what to accept are a bit complex.
*
* 1) if 'ignoresdpversion' has been set for this dialog, then
* we will just accept whatever they sent and assume it is
* a modification of the session, even if it is not
* 2) otherwise, if this is the first SDP we've seen from them
* we accept it
* 3) otherwise, if the new SDP version number is higher than the
* old one, we accept it
* 4) otherwise, if this SDP is in response to us requesting a switch
* to T.38, we accept the SDP, but also generate a warning message
* that this peer should have the 'ignoresdpversion' option set,
* because it is not following the SDP offer/answer RFC; if we did
* not request a switch to T.38, then we stop parsing the SDP, as it
* has not changed from the previous version
*/
if (ast_test_flag(&p->flags[1], SIP_PAGE2_IGNORESDPVERSION) ||
(p->sessionversion_remote < 0) ||
(p->sessionversion_remote < rua_version)) {
p->sessionversion_remote = rua_version;
p->session_modify = TRUE;
} else if (p->sessionversion_remote == rua_version) {
p->session_modify = FALSE;
ast_debug(2, "SDP version number same as previous SDP. Not parsing this SDP.\n");
return 0;
} else {
if (p->t38.state == T38_LOCAL_REINVITE) {
p->sessionversion_remote = rua_version;
p->session_modify = TRUE;
ast_log(LOG_WARNING, "Call %s responded to our T.38 reinvite without changing SDP version; 'ignoresdpversion' should be set for this peer.\n", p->callid);
} else {
p->session_modify = FALSE;
ast_debug(2, "Call %s responded to our reinvite without changing SDP version; ignoring SDP.\n", p->callid);
return 0;
}
}
/* Try to find first media stream */