From cdc1af48e63ad3558c385b2741aa7fa5f3e96099 Mon Sep 17 00:00:00 2001 From: Alexander Traud Date: Mon, 18 Jul 2016 12:13:25 +0200 Subject: [PATCH] res_rtp_asterisk: Count a roll-over of the sequence number even on lost packets. With this change, the initial RTP sequence number is randomly chosen not between 0 and 65535 (0xffff) but 0 and 32767 (0x7fff). This assures, the roll-over counter (ROC) synchronization is not lost for sRTP, when the very first RTP packets get lost; see http://srtp.sourceforge.net/faq.html#Q6 ASTERISK-26207 #close Change-Id: I9a527e3aa3ce8f3becc5131d7ba32b57b5845464 --- res/res_rtp_asterisk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/res/res_rtp_asterisk.c b/res/res_rtp_asterisk.c index d60440e8f6..3223cc9691 100644 --- a/res/res_rtp_asterisk.c +++ b/res/res_rtp_asterisk.c @@ -2536,7 +2536,7 @@ static int ast_rtp_new(struct ast_rtp_instance *instance, /* Set default parameters on the newly created RTP structure */ rtp->ssrc = ast_random(); - rtp->seqno = ast_random() & 0xffff; + rtp->seqno = ast_random() & 0x7fff; rtp->strict_rtp_state = (strictrtp ? STRICT_RTP_LEARN : STRICT_RTP_OPEN); if (strictrtp) { rtp_learning_seq_init(&rtp->rtp_source_learn, (uint16_t)rtp->seqno); -- 2.47.2