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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1977/">https://reviewboard.asterisk.org/r/1977/</a>
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<a href="https://reviewboard.asterisk.org/r/1977/diff/1/?file=28599#file28599line25254" style="color: black; font-weight: bold; text-decoration: underline;">/branches/1.8/channels/chan_sip.c</a>
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(Diff revision 1)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int handle_incoming(struct sip_pvt *p, struct sip_request *req, struct ast_sockaddr *addr, int *recount, int *nounlock)</pre></td>
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<th bgcolor="#e9eaa8" style="border-right: 1px solid #C0C0C0;" align="right"><font size="2">25254</font></th>
<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="kt">char</span> <span class="o">*</span><span class="n">tag</span> <span class="o">=</span> <span class="n">strstr</span><span class="p">(</span><span class="n">to_header</span><span class="p">,</span> <span class="s">";tag="</span><span class="p">);</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">const</span> <span class="kt">char</span> <span class="o">*</span><span class="n">to_header</span> <span class="o">=</span> <span class="n">get_header</span><span class="p">(</span><span class="n">req</span><span class="p">,</span> <span class="s">"To"</span><span class="p">);</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="o">*</span><span class="n">tag</span> <span class="o">=</span> <span class="sc">'\0'</span><span class="p">;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="kt">char</span> <span class="o">*</span><span class="n">totag</span> <span class="o">=</span> <span class="n">strstr</span><span class="p">(</span><span class="n">to_header</span><span class="p">,</span> <span class="s">";tag="</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="n">totag</span> <span class="o">+=</span> <span class="mi">5</span><span class="p">;</span> <span class="cm">/* ";tag=" */</span></pre></td>
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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="n">ast_string_field_set</span><span class="p">(</span><span class="n">p</span><span class="p">,</span> <span class="n">tag</span><span class="p">,</span> <span class="n">totag</span><span class="p">);</span></pre></td>
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<pre style="margin-left: 2em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">You should use gettag() here.
(And preferably all other strcasestr.*"tag=" should be replaced with a to be created hastag() that checks ";tag=" instead of "tag=".)</pre>
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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;">Otherwise it looks good, although I haven't tested it.</pre>
<p>- wdoekes</p>
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<p>On June 7th, 2012, 9:38 a.m., Mark Michelson wrote:</p>
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<div>Review request for Asterisk Developers.</div>
<div>By Mark Michelson.</div>
<p style="color: grey;"><i>Updated June 7, 2012, 9:38 a.m.</i></p>
<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;">When Asterisk receives what it believes to be a dialog-starting INVITE with a to-tag, Asterisk will reply with a 481. There was an issue where Asterisk would not recognize the incoming ACK of the 481 because Asterisk's internally generated to-tag did not match the actual to-tag used in the transaction. My initial fix for this was to make Asterisk send its generated to-tag in the 481 to essentially "change" the to-tag of the transaction. This way, the UA would respond with an ACK with a matching to-tag and all would be happy.
Unfortunately, it was pointed out to me that just because Asterisk thinks that an INVITE is out-of-dialog doesn't make it so. For instance, Asterisk could crash with a SIP dialog up, be restarted, and then receive a reinvite for that dialog. The new Asterisk instance would have no knowledge of the dialog, so it would think the INVITE was out-of-dialog with an illegitimate to-tag. In this case, the sender of the reinvite would not recognize the 481 as being in-dialog and would thus continue retransmitting the reinvite until the transaction timed out.
The new approach here is to update Asterisk's local tag to be the to-tag present in the INVITE in the case that Asterisk will be transmitting a 481 response. Taking this approach meant having to change the local tag to be a string field instead of a static buffer and rewriting the make_our_tag() method.</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;">I have tested using Walter Doekes's 481 test. The 481 that Asterisk sends has the same to-tag as the INVITE, and Asterisk properly recognizes the inbound ACK.</pre>
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<b style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Bugs: </b>
<a href="https://issues.asterisk.org/jira/browse/ASTERISK-19892">ASTERISK-19892</a>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>/branches/1.8/channels/chan_sip.c <span style="color: grey">(368625)</span></li>
<li>/branches/1.8/channels/sip/include/sip.h <span style="color: grey">(368624)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1977/diff/" style="margin-left: 3em;">View Diff</a></p>
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