osmux: Fix osmux seqnum incremented globally instead of per circuit

There's no real use in having a global seqnum. The seqnum, as specified
by the osmux protocol specification, relates to that of the RTP
seq+timestamp, hence it is per circuit.
Having it per circuit allows detecting gaps and lost batches on the
receiver side, applying the Marker bit on the re-assembled RTP packets.

As a resut of the fix, tests/osmux/osmux_test part validating Marker bit
started failing. It failed because it was wrongly written to start with,
since it used only one osmux_out_handle for the 4 CIDs in use, which was
wrong, since each CID must have its own osmux_out_handle as state is
kept there per circuit.

Related: SYS#5987
Change-Id: I562de6a871d8a35475c314ca107c2a12b55d6683

src/osmux.c

@@ -298,7 +298,6 @@ struct osmux_batch {
 	struct osmux_hdr	*osmuxh;
 	struct llist_head	circuit_list;
 	unsigned int		remaining_bytes;
-	uint8_t			seq;
 	uint32_t		nmsgs;
 	int			ndummy;
 };
@@ -309,6 +308,7 @@ struct osmux_circuit {
 	struct llist_head	msg_list;
 	int			nmsgs;
 	int			dummy;
+	uint8_t			seq;
 };
 
 /* returns: 1 if batch is full, 0 if batch still not full, negative on error. */
@@ -357,7 +357,7 @@ struct osmux_input_state {
 	struct rtp_hdr	*rtph;
 	struct amr_hdr	*amrh;
 	uint32_t	amr_payload_len;
-	int		ccid;
+	struct osmux_circuit *circuit;
 	int		add_osmux_hdr;
 };
 
@@ -371,8 +371,8 @@ static int osmux_batch_put(struct osmux_batch *batch,
 		osmuxh->ft = OSMUX_FT_VOICE_AMR;
 		osmuxh->ctr = 0;
 		osmuxh->rtp_m = osmuxh->rtp_m || state->rtph->marker;
-		osmuxh->seq = batch->seq++;
-		osmuxh->circuit_id = state->ccid;
+		osmuxh->seq = state->circuit->seq++;
+		osmuxh->circuit_id = state->circuit->ccid;
 		osmuxh->amr_ft = state->amrh->ft;
 
 		/* annotate current osmux header */
@@ -412,7 +412,7 @@ static void osmux_encode_dummy(struct osmux_batch *batch, uint8_t batch_factor,
 	osmuxh->amr_f = 0;
 	osmuxh->amr_q= 0;
 	osmuxh->seq = 0;
-	osmuxh->circuit_id = state->ccid;
+	osmuxh->circuit_id = state->circuit->ccid;
 	osmuxh->amr_cmr = 0;
 	osmuxh->amr_ft = AMR_FT_3;
 	msgb_put(state->out_msg, sizeof(struct osmux_hdr));
@@ -445,7 +445,7 @@ static struct msgb *osmux_build_batch(struct osmux_batch *batch,
 		if (circuit->dummy) {
 			struct osmux_input_state state = {
 				.out_msg	= batch_msg,
-				.ccid		= circuit->ccid,
+				.circuit	= circuit,
 			};
 			osmux_encode_dummy(batch, batch_factor, &state);
 			continue;
@@ -455,7 +455,7 @@ static struct msgb *osmux_build_batch(struct osmux_batch *batch,
 			struct osmux_input_state state = {
 				.msg		= cur,
 				.out_msg	= batch_msg,
-				.ccid		= circuit->ccid,
+				.circuit	= circuit,
 			};
 			uint32_t amr_len;
 #ifdef DEBUG_MSG

tests/osmux/osmux_test.c

@@ -102,7 +102,7 @@ static void tx_cb(struct msgb *msg, void *data)
 	msgb_free(msg);
 }
 
-static struct osmux_out_handle *h_output;
+static struct osmux_out_handle *h_output[4];
 
 static void osmux_deliver(struct msgb *batch_msg, void *data)
 {
@@ -116,7 +116,7 @@ static void osmux_deliver(struct msgb *batch_msg, void *data)
 	 * in a list. Then, reconstruct transmission timing.
 	 */
 	while((osmuxh = osmux_xfrm_output_pull(batch_msg)) != NULL)
-		osmux_xfrm_output_sched(h_output, osmuxh);
+		osmux_xfrm_output_sched(h_output[osmuxh->circuit_id], osmuxh);
 	msgb_free(batch_msg);
 }
 
@@ -132,7 +132,8 @@ static void sigalarm_handler(int foo)
 	exit(EXIT_FAILURE);
 }
 
-static void osmux_test_marker(int ccid) {
+static void osmux_test_marker(int num_ccid)
+{
 	struct msgb *msg;
 	struct rtp_hdr *rtph = (struct rtp_hdr *)rtp_pkt;
 	struct rtp_hdr *cpy_rtph;
@@ -145,7 +146,7 @@ static void osmux_test_marker(int ccid) {
 		seq++;
 		rtph->sequence = htons(seq);
 
-		for (j=0; j<4; j++) {
+		for (j = 0; j < num_ccid; j++) {
 			msg = msgb_alloc(1500, "test");
 			if (!msg)
 				exit(EXIT_FAILURE);
@@ -160,7 +161,7 @@ static void osmux_test_marker(int ccid) {
 			}
 
 			rtp_pkts++;
-			while (osmux_xfrm_input(&h_input, msg, j + ccid) > 0) {
+			while (osmux_xfrm_input(&h_input, msg, j) > 0) {
 				osmux_xfrm_input_deliver(&h_input);
 			}
 		}
@@ -265,13 +266,15 @@ int main(void)
 	log_set_print_category_hex(osmo_stderr_target, 0);
 	log_set_use_color(osmo_stderr_target, 0);
 
-	h_output = osmux_xfrm_output_alloc(NULL);
-	osmux_xfrm_output_set_rtp_ssrc(h_output, 0x7000000);
-	osmux_xfrm_output_set_rtp_pl_type(h_output, 98);
-	osmux_xfrm_output_set_tx_cb(h_output, tx_cb, NULL);
-	/* These fields are set using random() */
-	h_output->rtp_seq = 9158;
-	h_output->rtp_timestamp = 1681692777;
+	for (i = 0; i < ARRAY_SIZE(h_output); i++) {
+		h_output[i] = osmux_xfrm_output_alloc(NULL);
+		osmux_xfrm_output_set_rtp_ssrc(h_output[i], 0x7000000 + i);
+		osmux_xfrm_output_set_rtp_pl_type(h_output[i], 98);
+		osmux_xfrm_output_set_tx_cb(h_output[i], tx_cb, NULL);
+		/* These fields are set using random() */
+		h_output[i]->rtp_seq = 9158;
+		h_output[i]->rtp_timestamp = 1681692777;
+	}
 
 	/* If the test takes longer than 10 seconds, abort it */
 	alarm(10);
@@ -280,7 +283,7 @@ int main(void)
 	osmux_xfrm_input_init(&h_input);
 	for (i = 0; i < 4; i++)
 		osmux_xfrm_input_open_circuit(&h_input, i, 0);
-	osmux_test_marker(0);
+	osmux_test_marker(4);
 	for (i = 0; i < 4; i++)
 		osmux_xfrm_input_close_circuit(&h_input, i);
 	osmux_xfrm_input_fini(&h_input);