[asterisk-bugs] [JIRA] (ASTERISK-24873) Cancelling transmission of packet loop wrap around

[Y Ateya (JIRA)]

Y Ateya created ASTERISK-24873:
----------------------------------

             Summary: Cancelling transmission of packet loop wrap around
                 Key: ASTERISK-24873
                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-24873
             Project: Asterisk
          Issue Type: Bug
      Security Level: None
            Reporter: Y Ateya
            Severity: Minor


In IAX, when a packet is received with sequence number, all not-yet-ACKed packets with lower sequence number shall be considered ACKed.

Sometimes after VNAK is recieved, the first packet sequence number makes the for loop run for useless 255 times.

check attachment: use_case.txt for extracted sequence of packets.
check attachment: client_logs_cancelling_packet_issue.txt.bz2 for a full log with many occurrences of this issue.

{code:title=The affected for loop|borderStyle=solid}
			/* First we have to qualify that the ACKed value is within our window */
			if (iaxs[fr->callno]->rseqno >= iaxs[fr->callno]->oseqno || (fr->iseqno >= iaxs[fr->callno]->rseqno && fr->iseqno < iaxs[fr->callno]->oseqno))
				x = fr->iseqno;
			else
				x = iaxs[fr->callno]->oseqno;
			if ((x != iaxs[fr->callno]->oseqno) || (iaxs[fr->callno]->oseqno == fr->iseqno)) {
				/* The acknowledgement is within our window.  Time to acknowledge everything
				   that it says to */
				for (x=iaxs[fr->callno]->rseqno; x != fr->iseqno; x++) {
					/* Ack the packet with the given timestamp */
					if (iaxdebug)
						ast_debug(1, "Cancelling transmission of packet %d\n", x);
{code}

"Cancelling transmission of packet X" shall be printed only for packets with lower sequence number than received packet.

Simple solution of using `<` for checking end of loop is not enough as it don't handle sequence number wrap around.

Note that there is not functional effect of this issue. It just blocks its thread in useless 255 loop.



--
This message was sent by Atlassian JIRA
(v6.2#6252)