Re: in_cksum() for ip packets with multiple mbufs

From: Simon 'corecode' Schubert (corecode_at_fs.ei.tum.de)
Date: 10/24/05

  • Next message: FreeBSD bugmaster: "Current problem reports assigned to you" 
    Date: Mon, 24 Oct 2005 11:51:01 +0200
To: kamal kc <kamal_ckk@yahoo.com>

    kamal kc wrote:
    > - final thing does this makes any difference
    > (calling the htons() twice):
    >
    > ip->ip_id=htons(ip->ip_id);
    > ip->ip_id=htons(ip->ip_id);

    on little endian machines: yes. on big endian machines: no. So don't
    do it. :)

    freebsd has several fields of the ip headerin host byte order to speed
    up access. they get converted to network byte order at a very late
    stage of the ip output path.

    cheers
       simon 

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