sip - exosip always answer twice when receive invite event

Question

I'm new in sip and use exosip to develop a sip gateway.
I found my gate way is always send answer twice, but the log in my program just print once.
I don't know what happened and how to fix this problem.

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UPDATE: I update my version to 5.2.0, but the problem still exists. Also, I found there exists duplicated RTP connections:

The question most bothers me is that audio packets are duplicated, which makes high packet loss rate:

question from:https://stackoverflow.com/questions/65938443/exosip-always-answer-twice-when-receive-invite-event

Answer 1

In version 5.1.2, there was a major rewrite of DNS, UDP, TCP and TLS management. The rewrite was required to maximize performance and to reach the same results with select and epoll implementations. Those changes introduced issues resolved in incremental steps and 3 versions were published in a row: exosip 5.1.2, 5.1.3 and finally 5.2.0

Your issue was fixed only in 5.2.0 with this ChangeLog line:

* fix duplicate packets for TCP and TLS when several outgoing NICT are happening at the same time [since 5.1.2]

The git fix is this one:

https://git.savannah.nongnu.org/cgit/exosip.git/commit/?id=1fdc54ed38eaf5155f5702240586c472f2cc73d4

You can read the full ChangeLog here for details.

There as been 3 commits since 5.2.0 in the git which may be nice to have. access git here

Make sure you also use latest osip 5.2.0 or access git here. There was only one additionnal commit which is also interesting.

NOTE: In my own tests: I have seen only retransmission of REQUESTs, but I would not be surprised if the bug was also affecting ANSWERS? If you use already the latest version, please write me a mail.