On 2003-02-20 16:46, ?? ?? <[EMAIL PROTECTED]> wrote:
> hi,i have a question about tcp/ip stack,could you help me?
> when we send a tcp packet with tcp_maxopt(tcp_maxopt = min(my
> mss,mss offerd by opposite socket) +length of TCP options,as ecos
> does in function tcp_mss() of the file tcp_input.c) to IP,and IP
> insert some IP options into packet,so maybe length of whole IP
> packet > ifp->mtu,so Ip must fragment this tcp packet,and TCP failed
> to avoid fragmenting in host itsself.

> as we know,TCP always avoid to fragment as possible,maybe the
> condition above does not occur often,but it is possible.
> right?
> or wrong,please tell me,Thank you very much!

The comment above tcp_mss() says:

 * NOTE that this routine is only called when we process an incoming
 * segment, for outgoing segments only tcp_mssopt is called.

So, it won't be called for frames created by ip_output() :-)


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