Fix Incrementing Sequence Number For Retransmitted DTMF End Packets

In Asterisk 1.4+, a fix was put in place to increment the sequence number for
retransmitted DTMF end packets.  With the introduction of the RTP engine API in
1.8, the sequence number was no longer being incremented.  This patch fixes this
regression as well as cleans up a few lines that were not doing anything.

(closes issue ASTERISK-20295)
Reported by: Nitesh Bansal
Tested by: Michael L. Young
Patches: 
01_rtp_event_seq_num.patch uploaded by Nitesh Bansal (license 6418)
asterisk-20295-dtmf-fix-cleanup.diff uploaded by Michael L. Young (license 5026)

Review: https://reviewboard.asterisk.org/r/2083/


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@372185 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_rtp_asterisk.c

@@ -718,11 +718,10 @@ static int ast_rtp_dtmf_continuation(struct ast_rtp_instance *instance)
 	}
 
 	/* Actually create the packet we will be sending */
-	rtpheader[0] = htonl((2 << 30) | (1 << 23) | (rtp->send_payload << 16) | (rtp->seqno));
+	rtpheader[0] = htonl((2 << 30) | (rtp->send_payload << 16) | (rtp->seqno));
 	rtpheader[1] = htonl(rtp->lastdigitts);
 	rtpheader[2] = htonl(rtp->ssrc);
 	rtpheader[3] = htonl((rtp->send_digit << 24) | (0xa << 16) | (rtp->send_duration));
-	rtpheader[0] = htonl((2 << 30) | (rtp->send_payload << 16) | (rtp->seqno));
 
 	/* Boom, send it on out */
 	res = rtp_sendto(instance, (void *) rtpheader, hdrlen + 4, 0, &remote_address);
@@ -785,15 +784,16 @@ static int ast_rtp_dtmf_end_with_duration(struct ast_rtp_instance *instance, cha
 	}
 
 	/* Construct the packet we are going to send */
-	rtpheader[0] = htonl((2 << 30) | (1 << 23) | (rtp->send_payload << 16) | (rtp->seqno));
 	rtpheader[1] = htonl(rtp->lastdigitts);
 	rtpheader[2] = htonl(rtp->ssrc);
 	rtpheader[3] = htonl((digit << 24) | (0xa << 16) | (rtp->send_duration));
 	rtpheader[3] |= htonl((1 << 23));
-	rtpheader[0] = htonl((2 << 30) | (rtp->send_payload << 16) | (rtp->seqno));
 
 	/* Send it 3 times, that's the magical number */
 	for (i = 0; i < 3; i++) {
+
+		rtpheader[0] = htonl((2 << 30) | (rtp->send_payload << 16) | (rtp->seqno));
+
 		res = rtp_sendto(instance, (void *) rtpheader, hdrlen + 4, 0, &remote_address);
 		if (res < 0) {
 			ast_log(LOG_ERROR, "RTP Transmission error to %s: %s\n",
@@ -805,6 +805,8 @@ static int ast_rtp_dtmf_end_with_duration(struct ast_rtp_instance *instance, cha
 				    ast_sockaddr_stringify(&remote_address),
 				    rtp->send_payload, rtp->seqno, rtp->lastdigitts, res - hdrlen);
 		}
+
+		rtp->seqno++;
 	}
 
 	/* Oh and we can't forget to turn off the stuff that says we are sending DTMF */