[Asterisk-code-review] res rtp asterisk: Count a roll-over of the sequence number e... (asterisk[13])

[Anonymous Coward]

Anonymous Coward #1000019 has submitted this change and it was merged.

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

Approvals:
  George Joseph: Looks good to me, but someone else must approve
  Anonymous Coward #1000019: Verified
  Joshua Colp: Looks good to me, approved



diff --git a/res/res_rtp_asterisk.c b/res/res_rtp_asterisk.c
index 8055e87..9db5aef 100644
--- a/res/res_rtp_asterisk.c
+++ b/res/res_rtp_asterisk.c
@@ -2592,7 +2592,7 @@
 
 	/* 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);

-- 
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Gerrit-MessageType: merged
Gerrit-Change-Id: I9a527e3aa3ce8f3becc5131d7ba32b57b5845464
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: Alexander Traud <pabstraud at compuserve.com>
Gerrit-Reviewer: Anonymous Coward #1000019
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>