Ticket #527: ticket527.patch

pjmedia/src/pjmedia/sdp_neg.c

@@ -648 +648 @@
                                   pj_bool_t allow_asym,
                                   pjmedia_sdp_session **p_active)
 {
-    unsigned mi;
+    unsigned omi = 0; /* Offer media index */
+    unsigned ami = 0; /* Answer media index */
     pj_bool_t has_active = PJ_FALSE;
     pj_status_t status;
 
@@ -656 +657 @@
     PJ_ASSERT_RETURN(pool && offer && answer && p_active, PJ_EINVAL);
 
     /* Check that media count match between offer and answer */
-    if (offer->media_count != answer->media_count)
+    // Ticket #527, different media count is allowed for more interoperability.
+    // However, number of media in answer must be <= number of media in offer,
+    // and the media order must be same between offer and answer.
+    // if (offer->media_count != answer->media_count)
+    //     return PJMEDIA_SDPNEG_EMISMEDIA;
+    if (offer->media_count < answer->media_count)
         return PJMEDIA_SDPNEG_EMISMEDIA;
 
     /* Now update each media line in the offer with the answer. */
-    for (mi=0; mi<offer->media_count; ++mi) {
-        status = process_m_answer(pool, offer->media[mi], answer->media[mi],
+    for (omi=0; omi<offer->media_count; ++omi) {
+
+        if (ami == answer->media_count) {
+            /* No answer media to be negotiated */
+            remove_all_media_directions(offer->media[omi]);
+            pjmedia_sdp_media_deactivate(pool, offer->media[omi]);
+            continue;
+        }
+
+        status = process_m_answer(pool, offer->media[omi], answer->media[ami],
                                   allow_asym);
+
+        /* If media type is mismatched, deactivate the media instead of return
+         * non PJ_SUCCESS.
+         */
+        if (status == PJMEDIA_SDPNEG_EINVANSMEDIA) {
+            remove_all_media_directions(offer->media[omi]);
+            pjmedia_sdp_media_deactivate(pool, offer->media[omi]);
+            continue;
+        }
+
         if (status != PJ_SUCCESS)
             return status;
 
-        if (offer->media[mi]->desc.port != 0)
+        if (offer->media[omi]->desc.port != 0)
             has_active = PJ_TRUE;
+
+        ++ami;
     }
 
+    /* There should be unordered/ambigue answer if there is any unprocessed 
+     * media of the answer.
+     */
+    if (ami < answer->media_count)
+        return PJMEDIA_SDPNEG_EINVANSMEDIA;
+
     *p_active = offer;
 
     return has_active ? PJ_SUCCESS : PJMEDIA_SDPNEG_ENOMEDIA;