Re: [Sip] ABNF issue

[Christer Holmberg <christer.holmberg@lmf.ericsson.se>]

Hi Jonathan,

> Christer Holmberg wrote:
> > Hi,
> >
> > The ABNF syntax in RFC3261 says the following things:
> >
> > LWS              =  [*WSP CRLF] 1*WSP ; linear whitespace
> >
> > Request          = Request-Line
> >                           *( message-header )
> >                           CRLF
> >                           [ message-body ]
> >
> > message-body  =  *OCTET
> >
> > Also, the syntax says that every message-header ends with CTRL.
> >
> > Now, the spec says that the SIP part of a message ends with CTRL CTRL.
> >
> > However, if the message-body part starts with one or more WSP, won't the
> >
> > CRLF between the message-body be interpreted as LWS instead? Ie, there
> > will NOT be CRLF CRLF at the end of the SIP part of message, but instead
> >
> > CRLF LWS.
>
> I don't know how you come to this conclusion. If the body starts with
> LWS, you will see a CRLF after the last header field, another CRLF
> before the body, and then an LWS which is the first byte of the body. Thus:
>
> CRLF CRLF LWS
>
> which is fine.

The body does not start with LWS. The body starts with WSP (RFC3261 doesn't
define what WSP is, but if I remember correct it is SP or TAB). So, in that
case you will have:

CRLF CRLF WSP

...which, according to the ABNF is:

CRLF LWS

Regards,

Christer Holmberg
Ericsson Finland


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