Do not allow native RTP bridging if packetization of media streams differs.

The RTP engine will no longer allow for local and remote native RTP bridges
if packetization of streams differs. Allowing native bridging in this scenario
has been known to cause FAX failures.

(closes ASTERISK-20650)
Reported by: Maciej Krajewski
Patches:
	ASTERISK-20659.patch uploaded by Mark Michelson (License #5049)

Review: https://reviewboard.asterisk.org/r/2319
........

Merged revisions 381281 from http://svn.asterisk.org/svn/asterisk/branches/1.8

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@381306 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/main/rtp_engine.c b/main/rtp_engine.c
index e7680ed52c6584b53dc03140cdc06583d66c109b..dc2983637c26e7d1f2187f32f44248e7ffca0bef 100644 (file)
--- a/main/rtp_engine.c
+++ b/main/rtp_engine.c
@@ -1460,6 +1460,7 @@ enum ast_bridge_result ast_rtp_instance_bridge(struct ast_channel *c0, struct as
        struct ast_format_cap *cap0 = ast_format_cap_alloc_nolock();
        struct ast_format_cap *cap1 = ast_format_cap_alloc_nolock();
        int unlock_chans = 1;
+       int read_ptime0, read_ptime1, write_ptime0, write_ptime1;
 
        if (!cap0 || !cap1) {
                unlock_chans = 0;
@@ -1568,6 +1569,18 @@ enum ast_bridge_result ast_rtp_instance_bridge(struct ast_channel *c0, struct as
                goto done;
        }
 
+       read_ptime0 = (ast_codec_pref_getsize(&instance0->codecs.pref, ast_channel_rawreadformat(c0))).cur_ms;
+       read_ptime1 = (ast_codec_pref_getsize(&instance1->codecs.pref, ast_channel_rawreadformat(c1))).cur_ms;
+       write_ptime0 = (ast_codec_pref_getsize(&instance0->codecs.pref, ast_channel_rawwriteformat(c0))).cur_ms;
+       write_ptime1 = (ast_codec_pref_getsize(&instance1->codecs.pref, ast_channel_rawwriteformat(c1))).cur_ms;
+
+       if (read_ptime0 != write_ptime1 || read_ptime1 != write_ptime0) {
+               ast_debug(1, "Packetization differs between RTP streams (%d != %d or %d != %d). Cannot native bridge in RTP\n",
+                               read_ptime0, write_ptime1, read_ptime1, write_ptime0);
+               res = AST_BRIDGE_FAILED_NOWARN;
+               goto done;
+       }
+
        instance0->glue = glue0;
        instance1->glue = glue1;
        instance0->chan = c0;