[OpenSIPS-Devel] [ opensips-Bugs-2956739 ] SRV lookup not correct

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Bugs item #2956739, was opened at 2010-02-22 13:38
Message generated for change (Comment added) made by byron_clark
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Category: core
Group: 1.6.x
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Byron Clark (byron_clark)
Assigned to: Nobody/Anonymous (nobody)
Summary: SRV lookup not correct

Initial Comment:
When using an SRV record to relay to a destination, OpenSIPS will repeatedly attempt to send the message to the second result in the lookup reply.

Here's an example (assume no response is received to the message):
- call t_relay() to relay to sip.example.com
- OpenSIPS performs SRV lookup for _sip._udp.sip.example.com
- DNS responds with sip1.example.com, sip2.example.com, sip3.example.com, sip4.example.com (equal priority)
- OpenSIPS performs A lookup for sip1.example.com
- OpenSIPS relays the message to sip1.example.com (including retransmits)
- OpenSIPS performs A lookulp for sip2.example.com
- OpenSIPS relays the message to sip2.example.com (including retransmits)

At this point, OpenSIPS should attempt to use sip3.example.com, but instead continues to lookup and then send the message to sip2.example.com until these errors show up in the log:
Feb 18 16:36:08 bgw1 opensips[1745]: ERROR:tm:add_uac: maximum number of branches exceeded
Feb 18 16:36:08 bgw1 opensips[1745]: ERROR:tm:t_forward_nonack: failure to add branches

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>Comment By: Byron Clark (byron_clark)
Date: 2010-02-22 13:40

Message:
The attached patch (against the 1.6 branch) causes OpenSIPS to correctly
walk through all of the SRV responses instead of continuing to use the same
entry.

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