Re: [sipcore] Content-Length in multipart body parts

Paul Kyzivat <pkyzivat@alum.mit.edu> Mon, 02 April 2012 22:37 UTC

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Date: Mon, 02 Apr 2012 18:37:07 -0400
From: Paul Kyzivat <pkyzivat@alum.mit.edu>
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To: Hadriel Kaplan <HKaplan@acmepacket.com>
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Cc: "Dale R (Dale) Worley" <dworley@avaya.com>, "<sipcore@ietf.org>" <sipcore@ietf.org>
Subject: Re: [sipcore] Content-Length in multipart body parts
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On 4/2/12 6:21 PM, Hadriel Kaplan wrote:
>
> Ugh.  Yeah, that's not good for examples to show.
> So what's the solution?  Errata?

Yes, I think the errata process is the right one for this.

	Thanks,
	Paul

> -hadriel
> p.s. I like the "Suspicious Line" thing - all RFC lines are suspicious! ;)
>
>
> On Apr 2, 2012, at 2:12 PM, Paul Kyzivat wrote:
>
>> [reposting with a subject line]
>>
>> On 4/2/12 6:53 PM, Worley, Dale R (Dale) wrote:
>>> Bruno Chatras has pointed out that a number of examples in various SIP-related
>>> RFCs show Content-Length header fields in the headers of body-parts of multipart
>>> entities.  MIME does not define the meaining of such header fields, as the MIME
>>> framing of body parts is done by the boundary markers.
>>>
>>> As Dale Moberg has pointed out, these header fields might not be truly incorrect
>>> but merely redundant or "to be ignored".
>>>
>>> But given that MIME multipart already frames the body-parts, Content-Length
>>> headers on body-parts are never necessary.
>>>
>>> So it seems to me that we should decide on a "best practices" for the use of
>>> Content-Length in the headers of a body part, to clarify the ambiguities in the
>>> specifications, and to state whether it's preferable to include such a Content-Length
>>> or not.
>>>
>>> I've appended a list of all the examples carrying such Content-Length headers
>>> that I could find by automated means.
>>>
>>> Dale
>>> --------------------------------------------------------------------------------------------------------
>>> RFC 2848
>>>
>>>                         The PINT Service Protocol:
>>>     Extensions to SIP and SDP for IP Access to Telephone Call Services
>>>
>>> Suspicious line at rfc2848.txt:2195:       Content-Length: 236
>>> Suspicious line at rfc2848.txt:2209:       Content-Length:50
>>> Suspicious line at rfc2848.txt:2268:       Content-Length: 316
>>> Suspicious line at rfc2848.txt:2284:       Content-Length: 172
>>> Suspicious line at rfc2848.txt:2372:    Content-Length: 325
>>> Suspicious line at rfc2848.txt:2387:    Content-Length: 352
>>>
>>> Several of these body-part headers are not separated from the
>>> body-part contents by CR-LF-CR-LF.
>>>
>>> RFC 3261
>>>
>>>                      SIP: Session Initiation Protocol
>>>
>>> Suspicious line at rfc3261.txt:11846:         Content-Length: 231
>>>
>>> RFC 3892
>>>
>>>        The Session Initiation Protocol (SIP) Referred-By Mechanism
>>>
>>> Suspicious line at rfc3892.txt:642:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:687:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:702:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:879:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:887:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:938:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:964:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:972:       Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:1056:      Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:1106:      Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:1168:      Content-Length: (appropriate value)
>>> Suspicious line at rfc3892.txt:1196:      Content-Length: (appropriate value)
>>>
>>> RFC 3893
>>>
>>>                     Session Initiation Protocol (SIP)
>>>                  Authenticated Identity Body (AIB) Format
>>>
>>> Suspicious line at rfc3893.txt:249:    Content-Length: 147
>>> (This has an extra CR-LF before the body-part headers.)
>>> Suspicious line at rfc3893.txt:263:    Content-Length: 608
>>>
>>> RFC 4463
>>>
>>>                  A Media Resource Control Protocol (MRCP)
>>>                Developed by Cisco, Nuance, and Speechworks
>>>
>>> Suspicious line at rfc4463.txt:1705:        Content-Length:176
>>> Suspicious line at rfc4463.txt:1714:        Content-Length:104
>>> Suspicious line at rfc4463.txt:2977:       Content-Length:176
>>> (Also missing the CR-LF after the body part headers.)
>>> Suspicious line at rfc4463.txt:2985:       Content-Length:104
>>>
>>> RFC 5547
>>>
>>>        A Session Description Protocol (SDP) Offer/Answer Mechanism
>>>                          to Enable File Transfer
>>>
>>> Suspicious line at rfc5547.txt:1645:    Content-Length: [length of SDP]
>>> Suspicious line at rfc5547.txt:1670:    Content-Length: [length of image]
>>> Suspicious line at rfc5547.txt:2093:    Content-Length: [length of SDP]
>>> Suspicious line at rfc5547.txt:2118:    Content-Length: [length of image]
>>>
>>> RFC 5589
>>>
>>>         Session Initiation Protocol (SIP) Call Control - Transfer
>>>
>>> Suspicious line at rfc5589.txt:2609:    Content-Length: 2961
>>> (An extra CR-LF in the middle of the body part headers.)
>>> Suspicious line at rfc5589.txt:2677:    Content-Length: 156
>>> (An extra CR-LF in the middle of the body part headers.)
>>> Suspicious line at rfc5589.txt:2696:    Content-Length: 2961
>>>
>>> RFC 6086
>>>
>>>    Session Initiation Protocol (SIP) INFO Method and Package Framework
>>>
>>> Suspicious line at rfc6086.txt:1594:    Content-length: 59
>>> Suspicious line at rfc6086.txt:1620:    Content-length: 59
>>> Suspicious line at rfc6086.txt:1637:    Content-length: 59
>>> Suspicious line at rfc6086.txt:1664:    Content-length: 59
>>> _______________________________________________
>>> sipcore mailing list
>>> sipcore@ietf.org
>>> https://www.ietf.org/mailman/listinfo/sipcore
>>>
>>
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