Re: bridge callbacks in if_ed.c?

From: Luigi Rizzo (luigi_at_freebsd.org)
Date: 09/05/04

  • Next message: Matthew Dillon: "Re: bridge callbacks in if_ed.c?" 
    Date: Sun, 5 Sep 2004 14:20:36 -0700
To: Gleb Smirnoff <glebius@freebsd.org>

    On Mon, Sep 06, 2004 at 12:52:49AM +0400, Gleb Smirnoff wrote:
    > Luigi,
    >
    > I see that bridge callbacks are still living in if_ed.c
    > from FreeBSD 2.x times. See if_ed.c:2816. I think this is
    > not correct.
    >
    > Bridge code is called from ether_input(), which is
    > indirectly called from if_ed.c:2836.
    >
    > Any objections about attached patch?

    there are performance reasons to do this way -- grabbing
    the entire packet is expensive because it is done via programmed
    I/O, so the current code only grabs the header, does the
    filtering, and grabs the rest of the packet only if
    needed.

    Probably the current code runs bridge_in_ptr() twice, but I
    believe this is still cheaper than grabbing all packets
    entirely.

    I'd rather not apply the patch unless you can show that
    the current code leads to incorrect behaviour.

    cheers
    luigi

    > [ccing hackers@ and net@ to get more eyes reviewing]
    >
    > --
    > Totus tuus, Glebius.
    > GLEBIUS-RIPN GLEB-RIPE

    > Index: if_ed.c
    > ===================================================================
    > RCS file: /home/ncvs/src/sys/dev/ed/if_ed.c,v
    > retrieving revision 1.233
    > diff -u -r1.233 if_ed.c
    > --- if_ed.c 13 Aug 2004 23:04:23 -0000 1.233
    > +++ if_ed.c 5 Sep 2004 20:48:19 -0000
    > @@ -2810,26 +2810,9 @@
    > eh = mtod(m, struct ether_header *);
    >
    > /*
    > - * Don't read in the entire packet if we know we're going to drop it
    > - * and no bpf is active.
    > + * Get packet, including link layer address, from interface.
    > */
    > - if (!ifp->if_bpf && BDG_ACTIVE( (ifp) ) ) {
    > - struct ifnet *bif;
    > -
    > - ed_ring_copy(sc, buf, (char *)eh, ETHER_HDR_LEN);
    > - bif = bridge_in_ptr(ifp, eh) ;
    > - if (bif == BDG_DROP) {
    > - m_freem(m);
    > - return;
    > - }
    > - if (len > ETHER_HDR_LEN)
    > - ed_ring_copy(sc, buf + ETHER_HDR_LEN,
    > - (char *)(eh + 1), len - ETHER_HDR_LEN);
    > - } else
    > - /*
    > - * Get packet, including link layer address, from interface.
    > - */
    > - ed_ring_copy(sc, buf, (char *)eh, len);
    > + ed_ring_copy(sc, buf, (char *)eh, len);
    >
    > m->m_pkthdr.len = m->m_len = len;
    >

    > _______________________________________________
    > freebsd-hackers@freebsd.org mailing list
    > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
    > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"

    _______________________________________________
    freebsd-net@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-net
    To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"

  • Next message: Matthew Dillon: "Re: bridge callbacks in if_ed.c?"