cvs commit: src/sys/net if_ethersubr.c

[Ruslan Ermilov]

Hi Sam,

On Mon, Feb 14, 2005 at 08:30:08AM -0800, Sam Leffler wrote:
> Ruslan Ermilov wrote:
> >ru          2005-02-14 08:29:42 UTC
> >
> >  FreeBSD src repository
> >
> >  Modified files:
> >    sys/net              if_ethersubr.c 
> >  Log:
> >  If no vlan(4) interfaces are configured for the interface, and the
> >  driver did VLAN decapsulation in hardware, we were passing a frame
> >  as if it came for the parent (non-VLAN) interface.  Stop this from
> >  happening.
> >  
> >  Reminded by:    glebius
> >  Security:       This could pose a security risk in some setups
> >  
> >  Revision  Changes    Path
> >  1.183     +10 -3     src/sys/net/if_ethersubr.c
> >http://cvsweb.FreeBSD.org/src/sys/net/if_ethersubr.c.diff?r1=1.182&r2=1.183
> >
> >
> Looks like you should use m_tag_find instead of 
> m_tag_first+m_tag_locate.
> 
Unfortunately m_tag_find() is only the compatibility function and
doesn't work for FreeBSD mtags.

> This also has the potential to noticeably 
> affect performance so I think a better solution is needed.
> 
Here are my thoughts.  On a typical input path, there will be
either one or zero mtags, one if driver provided us with the
VLAN mtag, so effectively we replaced "ifp->if_nvlans" with
"m_tag_first(m) != NULL", and this doesn't look like a huge
performance downgrade to me, if at all.


Cheers,
-- 
Ruslan Ermilov
ru at FreeBSD.org
FreeBSD committer
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