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<p class="MsoNormal"><span lang="NL">Hello Community,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="NL"><o:p> </o:p></span></p>
<p class="MsoNormal">We were facing a weird issue in one of our Kamailio servers where custom htable entries were removed which did not belong to a particular call.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Background Information:<o:p></o:p></p>
<p class="MsoNormal">We use htable to store the call-id and a uuid when an INVITE message is received and remove these entries when the call is completed/failed (so on CANCEL, BYE, 4XX, 5XX, 6XX, etc).<o:p></o:p></p>
<p class="MsoNormal">In this case the function sht_rm_name_re was causing incremented call-id’s belonging to different calls to be removed from the htable, since the removal is based on regex and not the exact key.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">On INVITE we do this:<o:p></o:p></p>
<p class="MsoNormal">$var(reference) = $uuid(g);<o:p></o:p></p>
<p class="MsoNormal">$sht(calls=>$ci) = $ci;<o:p></o:p></p>
<p class="MsoNormal">$sht(calls=>$ci::reference) = $var(reference);<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">On BYE/4XX,5XX,6XX, etc we did this:<o:p></o:p></p>
<p class="MsoNormal">sht_rm_name_re("calls=>$ci");<o:p></o:p></p>
<p class="MsoNormal">sht_rm_name_re("calls=>$ci::reference");<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">SIPP generates incremented call-id’s, like this: <a href="mailto:1-14875@1.0.0.1">
1-14875@1.0.0.1</a>. <o:p></o:p></p>
<p class="MsoNormal">When you generate enough calls, for instance 30 calls, the 21<sup>st</sup> call will have the call-id
<a href="mailto:21-14875@1.0.0.1">21-14875@1.0.0.1</a>.<o:p></o:p></p>
<p class="MsoNormal">If for instance the BYE for the call-id <a href="mailto:1-14875@1.0.0.1">
1-14875@1.0.0.1</a> arrives before <a href="mailto:21-14875@1.0.0.1">21-14875@1.0.0.1</a> , both htable entries will be removed by the sht_rm_name_re function, since it matches based on regex.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">To fix this we made sure the function matches on the exact keys by doing this:<o:p></o:p></p>
<p class="MsoNormal">$var(callid) = '^' + $ci + '$';<o:p></o:p></p>
<p class="MsoNormal">$var(callid_reference) = '^' + $ci + '::reference' + '$';<o:p></o:p></p>
<p class="MsoNormal">sht_rm_name_re("calls=>$var(callid)");<o:p></o:p></p>
<p class="MsoNormal">sht_rm_name_re("calls=>$var(callid_reference)");<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hope this may help someone in the future facing the same issue.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Grant Bagdasarian<o:p></o:p></p>
<p class="MsoNormal">CM<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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