res_pjsip_sdp_rtp.c: Set preferred rx payload type mapping on incoming offers.

ASTERISK-25166
Reported by: Kevin Harwell

ASTERISK-17410
Reported by: Boris Fox

Change-Id: I97ecebc1ab9b5654fb918bf1f4c98c956b852369

diff --git a/res/res_pjsip_sdp_rtp.c b/res/res_pjsip_sdp_rtp.c
index 2ca1f98de78514f40465eb48099ea1b1396b9c96..f1314f52816fc13431aba0bfbb363a44580e7e35 100644 (file)
--- a/res/res_pjsip_sdp_rtp.c
+++ b/res/res_pjsip_sdp_rtp.c
@@ -286,8 +286,10 @@ static void get_codecs(struct ast_sip_session *session, const struct pjmedia_sdp
        }
 }
 
-static int set_caps(struct ast_sip_session *session, struct ast_sip_session_media *session_media,
-                   const struct pjmedia_sdp_media *stream)
+static int set_caps(struct ast_sip_session *session,
+       struct ast_sip_session_media *session_media,
+       const struct pjmedia_sdp_media *stream,
+       int is_offer)
 {
        RAII_VAR(struct ast_format_cap *, caps, NULL, ao2_cleanup);
        RAII_VAR(struct ast_format_cap *, peer, NULL, ao2_cleanup);
@@ -332,6 +334,13 @@ static int set_caps(struct ast_sip_session *session, struct ast_sip_session_medi
                return -1;
        }
 
+       if (is_offer) {
+               /*
+                * Setup rx payload type mapping to prefer the mapping
+                * from the peer that the RFC says we SHOULD use.
+                */
+               ast_rtp_codecs_payloads_xover(&codecs, &codecs, NULL);
+       }
        ast_rtp_codecs_payloads_copy(&codecs, ast_rtp_instance_get_codecs(session_media->rtp),
                session_media->rtp);
 
@@ -901,7 +910,7 @@ static int negotiate_incoming_sdp_stream(struct ast_sip_session *session, struct
                pj_strdup(session->inv_session->pool, &session_media->transport, &stream->desc.transport);
        }
 
-       if (set_caps(session, session_media, stream)) {
+       if (set_caps(session, session_media, stream, 1)) {
                return 0;
        }
        return 1;
@@ -1249,7 +1258,7 @@ static int apply_negotiated_sdp_stream(struct ast_sip_session *session, struct a
        /* Apply connection information to the RTP instance */
        ast_sockaddr_set_port(addrs, remote_stream->desc.port);
        ast_rtp_instance_set_remote_address(session_media->rtp, addrs);
-       if (set_caps(session, session_media, remote_stream)) {
+       if (set_caps(session, session_media, remote_stream, 0)) {
                return 1;
        }