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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/4084/">https://reviewboard.asterisk.org/r/4084/</a>
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<p style="margin-top: 0;">On October 15th, 2014, 8:37 p.m. UTC, <b>Mark Michelson</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/4084/diff/1/?file=68351#file68351line92" style="color: black; font-weight: bold; text-decoration: underline;">/trunk/res/res_pjsip_keepalive.c</a>
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(Diff revision 1)
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="n">pjsip_tpmgr_send_raw</span><span class="p">(</span><span class="n">pjsip_endpt_get_tpmgr</span><span class="p">(</span><span class="n">ast_sip_get_pjsip_endpoint</span><span class="p">()),</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">keepalive</span><span class="o">-></span><span class="n">transport</span><span class="o">-></span><span class="n">key</span><span class="p">.</span><span class="n">type</span><span class="p">,</span> <span class="o">&</span><span class="n">selector</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">,</span> <span class="n">keepalive_packet</span><span class="p">.</span><span class="n">ptr</span><span class="p">,</span> <span class="n">keepalive_packet</span><span class="p">.</span><span class="n">slen</span><span class="p">,</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="o">&</span><span class="n">keepalive</span><span class="o">-></span><span class="n">transport</span><span class="o">-></span><span class="n">key</span><span class="p">.</span><span class="n">rem_addr</span><span class="p">,</span> <span class="n">pj_sockaddr_get_len</span><span class="p">(</span><span class="o">&</span><span class="n">keepalive</span><span class="o">-></span><span class="n">transport</span><span class="o">-></span><span class="n">key</span><span class="p">.</span><span class="n">rem_addr</span><span class="p">),</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="nb">NULL</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">);</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Possible optimization:
Since tpmgr is having to create the exact same tdata every time you send a keepalive, it may be worth creating and storing your own tdata instead. Then you can just reuse the same tdata each time you send a keepalive.
Probably not worth doing unless we determine that there really is an issue here, but worth noting nonetheless.</pre>
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<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">I can't guarantee that would be safe to do because the raw method still stores some attempt specific information on the tdata and has a callback. Provided the callback happens within the call it could be fine, but if it happens later OR allocates any additional data from the tdata pool then I'm back at the beginning. I'd have to use an individual tdata and reset the pool and recreate state.</pre>
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<p style="margin-top: 0;">On October 15th, 2014, 8:37 p.m. UTC, <b>Mark Michelson</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/4084/diff/1/?file=68351#file68351line151" style="color: black; font-weight: bold; text-decoration: underline;">/trunk/res/res_pjsip_keepalive.c</a>
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(Diff revision 1)
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="k">case</span> <span class="n">PJSIP_TP_STATE_DISCONNECTED</span>:</pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">ao2_find</span><span class="p">(</span><span class="n">transports</span><span class="p">,</span> <span class="n">transport</span><span class="o">-></span><span class="n">obj_name</span><span class="p">,</span> <span class="n">OBJ_SEARCH_KEY</span> <span class="o">|</span> <span class="n">OBJ_NODATA</span> <span class="o">|</span> <span class="n">OBJ_UNLINK</span><span class="p">);</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="k">break</span><span class="p">;</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">I'm not very familiar with the PJSIP transport state machine, but I can see that there are two additional states, PJSIP_TP_STATE_SHUTDOWN and PJSIP_TP_STATE_DESTROY. Is it possible for a connected transport to enter one of those two states without first entering the disconnected state?</pre>
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<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">It is not.</pre>
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<p style="margin-top: 0;">On October 15th, 2014, 8:37 p.m. UTC, <b>Mark Michelson</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/4084/diff/1/?file=68351#file68351line152" style="color: black; font-weight: bold; text-decoration: underline;">/trunk/res/res_pjsip_keepalive.c</a>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="tb"> </span><span class="tb"> </span><span class="n">ao2_find</span><span class="p">(</span><span class="n">transports</span><span class="p">,</span> <span class="n">transport</span><span class="o">-></span><span class="n">obj_name</span><span class="p">,</span> <span class="n">OBJ_SEARCH_KEY</span> <span class="o">|</span> <span class="n">OBJ_NODATA</span> <span class="o">|</span> <span class="n">OBJ_UNLINK</span><span class="p">);</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Hm, seems like there may be a race condition here, but it may be benign. If a connection is disconnected, then the call to ao2_find() to remove the transport from the keepalive container may block until the current set of keepalives has completed being sent.
While the keepalives are being sent, it is possible that we may try to send a keepalive on the transport that just disconnected. That may just result in an error return from pjsip_tpmgr_send_raw(), but there's also that worry it could trip an assertion. Can you verify?</pre>
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<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Confirmed, there be no assertions that would occur.</pre>
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<p>- Joshua</p>
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<p>On October 15th, 2014, 6:08 p.m. UTC, Joshua Colp wrote:</p>
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<div>Review request for Asterisk Developers.</div>
<div>By Joshua Colp.</div>
<p style="color: grey;"><i>Updated Oct. 15, 2014, 6:08 p.m.</i></p>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
Asterisk
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Reusing connections is a good thing(tm). In the case of NAT it means that you have an actual way to exchange data back and forth. In practice, however, some things (such as PJSIP) close down the TCP connection after a short period of time (in the case of PJSIP for UAC it's 33 seconds). While PJSIP has a built in keepalive mechanism this is by default set to 90 seconds and can only be controlled at compile time.
The attached module implements its own keepalive which is configurable at runtime and does not require configuration. This sends a lightweight keepalive to keep the TCP (or TLS) connection open.</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Configured keepalives and used wireshark to verify that at the specific interval the message went out.</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>/trunk/res/res_pjsip_keepalive.c <span style="color: grey">(PRE-CREATION)</span></li>
<li>/trunk/configs/samples/pjsip.conf.sample <span style="color: grey">(425216)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/4084/diff/" style="margin-left: 3em;">View Diff</a></p>
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