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<p class="MsoNormal">We have a SIP provider who sends an INVITE with a Branch header.<o:p></o:p></p>
<p class="MsoNormal">Everything is fine in most cases. However, there are times they send a Branch header with a % character.<o:p></o:p></p>
<p class="MsoNormal">From what I have been told, the header is a token, so it is acceptable to include the % character.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">There seem to be two different issues with PJSIP processing of headers with the % character in tokenized fields.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Example.<o:p></o:p></p>
<p class="MsoNormal">branch=z9hG4bKf5s1psess0KGj0gRsgyJIBWEYL%QWIjkWmDXr8xnPVgaOBzOLSV28<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In one case, it can receive the portion and process it, but when sending out the same token it changes it to lower case. Example, received %8A portion, but sent %8a. This means it’s not a match for the token so the other side will not
match.<o:p></o:p></p>
<p class="MsoNormal">Received<o:p></o:p></p>
<p class="MsoNormal">branch=z9hG4bKf5s1psess0gbkeviMkQYREmK31pLWRKQ+FRmVzHQNG1Xv%8AnzLVA!;extension=QKIT3jRNBcmZT7yu5m7absBxXxlfn1kLwfYKYT0MOyY!<o:p></o:p></p>
<p class="MsoNormal">Sent<o:p></o:p></p>
<p class="MsoNormal">branch=z9hG4bKf5s1psess0gbkeviMkQYREmK31pLWRKQ+FRmVzHQNG1Xv%8anzLVA!;extension=QKIT3jRNBcmZT7yu5m7absBxXxlfn1kLwfYKYT0MOyY!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It another case, seems PJSIP has another scenario where the % character is processed as the escaped character if it would be printable character. Example, received %4C. The send replaces that portion with upper case L<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Received<o:p></o:p></p>
<p class="MsoNormal">branch=z9hG4bKf5s1psess0gbkeviMkQYREmK31pLWRKQ+FRmVzHQNG1Xv%4CnzLVA!;extension=QKIT3jRNBcmZT7yu5m7absBxXxlfn1kLwfYKYT0MOyY!<o:p></o:p></p>
<p class="MsoNormal">Sent<o:p></o:p></p>
<p class="MsoNormal">branch=z9hG4bKf5s1psess0gbkeviMkQYREmK31pLWRKQ+FRmVzHQNG1XvLnzLVA!;extension=QKIT3jRNBcmZT7yu5m7absBxXxlfn1kLwfYKYT0MOyY!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Dan<o:p></o:p></p>
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