MT#61802 retain offered codecs across answers

The `answer` processing empties out the list of codecs and leaves only
those that were accepted in the answer. Side effect of this is that if
another answer with a different list of codecs comes through, them the
codec-accept function is missing the original list of offered codecs and
can yield an incorrect result.

Fix this by storing a copy of the offered codecs at the end of the
`offer` processing, and then restore this list at the beginning of each
`answer` message.

Change-Id: I3c714e80689f3c5689637cc7d1eb2f203c292a15

daemon/call.c

@@ -664,6 +664,7 @@ struct call_media *call_media_new(call_t *call) {
 	med = uid_slice_alloc0(med, &call->medias.q);
 	med->call = call;
 	codec_store_init(&med->codecs, med);
+	codec_store_init(&med->offered_codecs, med);
 	med->media_subscribers_ht = subscription_ht_new();
 	med->media_subscriptions_ht = subscription_ht_new();
 	mutex_init(&med->dtmf_lock);
@@ -2507,6 +2508,9 @@ static void codecs_offer(struct call_media *media, struct call_media *other_medi
 	codec_handlers_update(media, other_media, .flags = flags, .sp = sp, 
 			.allow_asymmetric = !!(flags->allow_asymmetric_codecs),
 			.reset_transcoding = true);
+
+	// keep a copy of the final list of what was offered
+	codec_store_copy(&other_media->offered_codecs, &other_media->codecs);
 }
 
 __attribute__((nonnull(1, 2, 3, 4)))
@@ -2537,6 +2541,9 @@ static void codecs_answer(struct call_media *media, struct call_media *other_med
 	codec_store_offer(&other_media->codecs, &flags->codec_offer, &sp->codecs);
 	codec_store_check_empty(&other_media->codecs, &sp->codecs, flags);
 
+	// restore list of originally offered codecs
+	codec_store_copy(&media->codecs, &media->offered_codecs);
+
 	// update callee side codec handlers again (second pass after the offer) as we
 	// might need to update some handlers, e.g. when supplemental codecs have been
 	// rejected
@@ -4093,6 +4100,7 @@ void call_media_free(struct call_media **mdp) {
 	t_queue_clear(&md->streams);
 	t_queue_clear(&md->endpoint_maps);
 	codec_store_cleanup(&md->codecs);
+	codec_store_cleanup(&md->offered_codecs);
 	codec_handlers_free(md);
 	codec_handler_free(&md->t38_handler);
 	t38_gateway_put(&md->t38_gateway);

daemon/codec.c

@@ -5248,6 +5248,30 @@ void __codec_store_populate(struct codec_store *dst, struct codec_store *src, st
 		codec_store_cleanup(&orig_dst);
 }
 
+void codec_store_copy(struct codec_store *dst, struct codec_store *src) {
+	codec_store_init(dst, src->media);
+
+	for (__auto_type l = src->codec_prefs.head; l; l = l->next) {
+		rtp_payload_type *pt = l->data;
+		codec_store_add_end(dst, pt);
+		if (l == src->supp_link)
+			dst->supp_link = dst->codec_prefs.tail;
+	}
+
+	dst->strip_full = src->strip_full;
+	dst->strip_all = src->strip_all;
+
+#ifdef WITH_TRANSCODING
+	dst->tracker->all_touched = src->tracker->all_touched;
+
+	GHashTableIter iter;
+	g_hash_table_iter_init(&iter, src->tracker->touched);
+	void *key;
+	while (g_hash_table_iter_next(&iter, &key, NULL))
+		g_hash_table_insert(dst->tracker->touched, key, (void *) 0x1);
+#endif
+}
+
 void codec_store_strip(struct codec_store *cs, str_q *strip, str_case_ht except) {
 	for (__auto_type l = strip->head; l; l = l->next) {
 		str *codec = l->data;

include/call.h

@@ -504,6 +504,7 @@ struct call_media {
 	endpoint_map_q		endpoint_maps;
 
 	struct codec_store	codecs;
+	struct codec_store	offered_codecs;
 	sdp_attr_q		generic_attributes;			/* sdp_attr_new() */
 	sdp_attr_q		all_attributes;			/* sdp_attr_new() */
 	sdp_attr_print_f	*sdp_attr_print;

include/codec.h

@@ -136,6 +136,7 @@ void __codec_store_populate_reuse(struct codec_store *, struct codec_store *, st
 #define codec_store_populate_reuse(dst, src, ...) \
 	__codec_store_populate_reuse(dst, src, (struct codec_store_args) {__VA_ARGS__})
 __attribute__((nonnull(1, 2)))
+void codec_store_copy(struct codec_store *, struct codec_store *);
 void codec_store_add_raw(struct codec_store *cs, rtp_payload_type *pt);
 __attribute__((nonnull(1, 2)))
 void codec_store_strip(struct codec_store *, str_q *strip, str_case_ht except);

t/auto-daemon-tests.pl

@@ -83,6 +83,133 @@ sub stun_succ {
 
 
 
+new_call;
+
+offer('double answer codec change', { }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+c=IN IP4 198.51.100.35
+t=0 0
+m=audio 3000 RTP/AVP 0 8 9
+---------------------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0 8 9
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=rtpmap:8 PCMA/8000
+a=rtpmap:9 G722/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+answer('double answer codec change', { }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+c=IN IP4 198.51.100.35
+t=0 0
+m=audio 3000 RTP/AVP 0
+---------------------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+answer('double answer codec change', { }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+c=IN IP4 198.51.100.35
+t=0 0
+m=audio 3000 RTP/AVP 8
+---------------------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 8
+c=IN IP4 203.0.113.1
+a=rtpmap:8 PCMA/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+new_call;
+
+offer('double answer codec change with new to-tag', { }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+c=IN IP4 198.51.100.35
+t=0 0
+m=audio 3000 RTP/AVP 0 8 9
+---------------------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0 8 9
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=rtpmap:8 PCMA/8000
+a=rtpmap:9 G722/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+answer('double answer codec change with new to-tag', { }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+c=IN IP4 198.51.100.35
+t=0 0
+m=audio 3000 RTP/AVP 0
+---------------------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 0
+c=IN IP4 203.0.113.1
+a=rtpmap:0 PCMU/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+new_tt;
+
+answer('double answer codec change with new to-tag', { }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+c=IN IP4 198.51.100.35
+t=0 0
+m=audio 3000 RTP/AVP 8
+---------------------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.23
+s=tester
+t=0 0
+m=audio PORT RTP/AVP 8
+c=IN IP4 203.0.113.1
+a=rtpmap:8 PCMA/8000
+a=sendrecv
+a=rtcp:PORT
+SDP
+
+
+
+
 ($sock_a, $sock_b) = new_call([qw(198.51.100.65 3000)], [qw(198.51.100.65 3002)]);
 
 ($port_a) = offer('opus<>opus+DTMF', { }, <<SDP);