bridge callbacks in if_ed.c?

Matthew Dillon dillon at apollo.backplane.com
Sun Sep 5 14:37:31 PDT 2004


    Well, wait a second... are we talking about a lot of packets being
    discarded by the filter in 'normal' operation, or are we talking about
    an attack?  Because if we are takling about an attack the LAST ethernet
    device anyone would ever want to use would be ED.  i.e. they would be
    under a major cpu load anyway and would be far better served using a
    better ethernet card.  It seems silly to leave a major hack in the system
    just to support attacks on an ethernet device that nobody in their right
    mind would use if they expected to be attacked!  Also, most ED devices
    are limited to 10BaseT (?), it's hard to imagine how the added load could
    possibly make things any worse then they would otherwise be, and similarly
    hard to imagine why anyone would want to use a programmed-I/O interface
    at 100BaseT or greater speeds (I'd say that the poor guy would deserve
    what he gets from that!).

						-Matt

: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


More information about the freebsd-hackers mailing list