[Asterisk-code-review] res rtp asterisk: Count a roll-over of the sequence number e... (asterisk[11])

[Alexander Traud]

Alexander Traud has uploaded a new change for review.

  https://gerrit.asterisk.org/3222

Change subject: res_rtp_asterisk: Count a roll-over of the sequence number even on lost packets.
......................................................................

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
---
M res/res_rtp_asterisk.c
1 file changed, 1 insertion(+), 1 deletion(-)


  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/22/3222/1

diff --git a/res/res_rtp_asterisk.c b/res/res_rtp_asterisk.c
index d60440e..3223cc9 100644
--- a/res/res_rtp_asterisk.c
+++ b/res/res_rtp_asterisk.c
@@ -2536,7 +2536,7 @@
 
 	/* 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);

-- 
To view, visit https://gerrit.asterisk.org/3222
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I9a527e3aa3ce8f3becc5131d7ba32b57b5845464
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 11
Gerrit-Owner: Alexander Traud <pabstraud at compuserve.com>