cvs commit: src/sys/net if_tap.c

Bruce M Simpson bms at
Sat Feb 3 02:57:47 UTC 2007

bms         2007-02-03 02:57:46 UTC

  FreeBSD src repository

  Modified files:
    sys/net              if_tap.c 
  Drop unicast Ethernet frames not destined for the configured address
  of a tap(4) instance, if IFF_PROMISC is not set.
  In tap(4), we should emulate the effect IFF_PROMISC would have on
  hardware, otherwise we risk introducing layer 2 loops if tap(4) is
  used with bridges. This means not even bpf(4) gets to see them.
  This patch has been tested in a variety of situations. Multicast and
  broadcast frames are correctly allowed through. I have observed this
  behaviour causing problems with multiple QEMU instances hosted on
  the same FreeBSD machine.
  The checks in in ether_demux() [if_ethersubr.c, rev 1.222, line 638]
  are insufficient to prevent this bug from occurring, as ifp->if_vlantrunk
  will always be NULL for the non-vlan case.
  MFC after:      3 weeks
  PR:             86429
  Submitted by:   Pieter de Boer (with changes)
  Revision  Changes    Path
  1.68      +18 -0     src/sys/net/if_tap.c

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