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<p>Hello,</p>
<p>t_precheck_trans() is returning true if a SIP worker process has
received the SIP request and it is handling it at that moment.
However, in case of a retransmission, that can be at the moment
when the transaction was already created for the previous same
requests (e.g., via t_newtran() or the execution is in a
branch_route block). The specs require that a stateful proxy
re-sends the last response in case of a re-transmission.
t_check_trans() is used for that purpose, to see if the
transaction was already created and to what specs require.</p>
<p>If still not clear, I will try to add more details.</p>
<p>Cheers,<br>
Daniel<br>
</p>
<br>
<div class="moz-cite-prefix">On 04.08.17 21:45, Joe Baran wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CA+sTEg_N2jKrDPNLGUe5PC9poXvAQJwafB0diTKJzm+D8fB-uA@mail.gmail.com">
<div dir="ltr">Probably an elementary question, but we're
relatively new at digging into the details. We are trying to
understand the following block of config code and have a
question or two. Our assumption is the t_precheck_trans()
function tells us whether another packet has arrived already as
a retransmission. However, we're not clear on what the
t_check_trans() is doing assuming the condition is true. Any
direction on this?
<div><br>
</div>
<div>Thanks.<br>
<div><br>
</div>
<div>
<div>route[CHECK_RETRANS]</div>
<div>{</div>
<div> # handle retransmissions</div>
<div> if(t_precheck_trans()) {</div>
<div> t_check_trans();</div>
<div> exit;</div>
<div> }</div>
<div>}</div>
</div>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Joe Baran</div>
</div>
<br>
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<br>
<pre class="moz-signature" cols="72">--
Daniel-Constantin Mierla
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