Re: [Sip-implementors] SDP longer than that given in "Content-Lenght" header
From: "Aneesh Naik" <[EMAIL PROTECTED]> What should be the behavior when SDP is longer than that given in "Content-Length" header? If the SIP message arrives in a UDP datagram, or via some other protocol which "frames" each message, as you say, the excess bytes must be discarded. The RFC 3261 section 18.3 Framing states: If there are additional bytes in the transport packet beyond the end of the body, they MUST be discarded. So this means, SIP parser should discard the data beyond the length given by "Content-Lenght" header. In the below case the call should fail as we wont get enough data from SDP to complete the call as we will drop them. INVITE sip:[EMAIL PROTECTED]:5060 SIP/2.0 Via: SIP/2.0/UDP 10.10.1.209:5061;branch=z9hG4bK-15126-1-0 From: sipp ;tag=15126SIPpTag001 To: sut Call-ID: [EMAIL PROTECTED] CSeq: 1 INVITE Contact: sip:[EMAIL PROTECTED]:5061 Max-Forwards: 70 Subject: Performance Test Content-Type: application/sdp *Content-Length: 20* v=0 o=user1 53655765 2353687637 IN IP4 10.253.6.209 s=- c=IN IP4 10.253.6.209 t=0 0 m=audio 6001 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Please suggest what must be the behavior in this case. Which means that the message is effectively: INVITE sip:[EMAIL PROTECTED]:5060 SIP/2.0 Via: SIP/2.0/UDP 10.10.1.209:5061;branch=z9hG4bK-15126-1-0 From: sipp ;tag=15126SIPpTag001 To: sut Call-ID: [EMAIL PROTECTED] CSeq: 1 INVITE Contact: sip:[EMAIL PROTECTED]:5061 Max-Forwards: 70 Subject: Performance Test Content-Type: application/sdp Content-Length: 20 v=0 o=user1 5365576 That is not validly formed SDP, since the o-line does not have the correct syntax. Your SDP parser should detect this. There is no defined error code for this situation, but 488 seems to be the closest in meaning. You can add a Warning header to the reponse that contains text explaining the problem with the invalid SDP. And as Attila says, tell the vendor about their problem. If the SIP message comes in via TCP or another "unframed" (stream) protocol, the Content-Length defines where the end of the SIP message is. The following bytes start the next SIP message. In this case, they are: 5 2353687637 IN IP4 10.253.6.209 s=- c=IN IP4 10.253.6.209 t=0 0 m=audio 6001 RTP/AVP 0 a=rtpmap:0 PCMU/8000 which is syntactically invalid. Dale ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
Re: [Sip-implementors] SDP longer than that given in "Content-Lenght"header
Comments Inline... Regards, Nataraju A B > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Aneesh Naik > Sent: Thursday, December 20, 2007 5:33 PM > To: Sip-implementors@lists.cs.columbia.edu > Subject: [Sip-implementors] SDP longer than that given in > "Content-Lenght"header > > Hi, > > What should be the behavior when SDP is longer than that > given in "Content-Length" header? > > The RFC 3261 section 18.3 Framing states: > If there are additional bytes in the transport packet beyond > the end of the body, they MUST be discarded. > > So this means, SIP parser should discard the data beyond the > length given by "Content-Lenght" header. > In the below case the call should fail as we wont get enough > data from SDP to complete the call as we will drop them. > > INVITE sip:[EMAIL PROTECTED]:5060 SIP/2.0 > Via: SIP/2.0/UDP 10.10.1.209:5061;branch=z9hG4bK-15126-1-0 > From: sipp ;tag=15126SIPpTag001 > To: sut > Call-ID: [EMAIL PROTECTED] > CSeq: 1 INVITE > Contact: sip:[EMAIL PROTECTED]:5061 > Max-Forwards: 70 > Subject: Performance Test > Content-Type: application/sdp > *Content-Length: 20* > > v=0 > o=user1 53655765 2353687637 IN IP4 10.253.6.209 > s=- > c=IN IP4 10.253.6.209 > t=0 0 > m=audio 6001 RTP/AVP 0 > a=rtpmap:0 PCMU/8000 > > > Please suggest what must be the behavior in this case. > [ABN] since this message is received over UDP transport, it would be preferred to consider whole packet and give less precedence to content-length header value. Even RFC.3261 suggests discard the rest of the bytes, but being liberal here would make the UA implementation more robust also. In case of TCP transport you should use the content-length header value strictly to determine the body of the received SIP request/response. This is my understanding, please add on if something better or preferred alternatives are available > Thanks, > Aneesh > ___ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
Re: [Sip-implementors] SDP longer than that given in "Content-Lenght"header
Discard the extra bytes. You have no choice. And tell the UA vendor to fix their implementation. Regards, Attila -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Aneesh Naik Sent: 20 December 2007 12:03 To: Sip-implementors@lists.cs.columbia.edu Subject: [Sip-implementors] SDP longer than that given in "Content-Lenght"header Hi, What should be the behavior when SDP is longer than that given in "Content-Length" header? The RFC 3261 section 18.3 Framing states: If there are additional bytes in the transport packet beyond the end of the body, they MUST be discarded. So this means, SIP parser should discard the data beyond the length given by "Content-Lenght" header. In the below case the call should fail as we wont get enough data from SDP to complete the call as we will drop them. INVITE sip:[EMAIL PROTECTED]:5060 SIP/2.0 Via: SIP/2.0/UDP 10.10.1.209:5061;branch=z9hG4bK-15126-1-0 From: sipp ;tag=15126SIPpTag001 To: sut Call-ID: [EMAIL PROTECTED] CSeq: 1 INVITE Contact: sip:[EMAIL PROTECTED]:5061 Max-Forwards: 70 Subject: Performance Test Content-Type: application/sdp *Content-Length: 20* v=0 o=user1 53655765 2353687637 IN IP4 10.253.6.209 s=- c=IN IP4 10.253.6.209 t=0 0 m=audio 6001 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Please suggest what must be the behavior in this case. Thanks, Aneesh ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
[Sip-implementors] SDP longer than that given in "Content-Lenght" header
Hi, What should be the behavior when SDP is longer than that given in "Content-Length" header? The RFC 3261 section 18.3 Framing states: If there are additional bytes in the transport packet beyond the end of the body, they MUST be discarded. So this means, SIP parser should discard the data beyond the length given by "Content-Lenght" header. In the below case the call should fail as we wont get enough data from SDP to complete the call as we will drop them. INVITE sip:[EMAIL PROTECTED]:5060 SIP/2.0 Via: SIP/2.0/UDP 10.10.1.209:5061;branch=z9hG4bK-15126-1-0 From: sipp ;tag=15126SIPpTag001 To: sut Call-ID: [EMAIL PROTECTED] CSeq: 1 INVITE Contact: sip:[EMAIL PROTECTED]:5061 Max-Forwards: 70 Subject: Performance Test Content-Type: application/sdp *Content-Length: 20* v=0 o=user1 53655765 2353687637 IN IP4 10.253.6.209 s=- c=IN IP4 10.253.6.209 t=0 0 m=audio 6001 RTP/AVP 0 a=rtpmap:0 PCMU/8000 Please suggest what must be the behavior in this case. Thanks, Aneesh ___ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
