Fix wrap around for rtp (bug #5595)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@7069 65c4cc65-6c06-0410-ace0-fbb531ad65f3

rtp.c

@@ -1098,6 +1098,8 @@ static unsigned int calc_txstamp(struct ast_rtp *rtp, struct timeval *delivery)
 	/* Use previous txcore if available */
 	t = (delivery && !ast_tvzero(*delivery)) ? *delivery : ast_tvnow();
 	ms = ast_tvdiff_ms(t, rtp->txcore);
+	if (ms < 0)
+		ms = 0;
 	/* Use what we just got for next time */
 	rtp->txcore = t;
 	return (unsigned int) ms;
@@ -1226,7 +1228,7 @@ static int ast_rtp_raw_write(struct ast_rtp *rtp, struct ast_frame *f, int codec
 	char iabuf[INET_ADDRSTRLEN];
 	int hdrlen = 12;
 	int res;
-	int ms;
+	unsigned int ms;
 	int pred;
 	int mark = 0;