vge(4) bad checksum

[Ruslan Ermilov]

Hi,

On Sun, Dec 17, 2006 at 03:52:49PM -0500, Kris Kennaway wrote:
> On Sun, Dec 17, 2006 at 11:46:24PM +0300, Andrew Pantyukhin wrote:
> > I'm not sure what it's all about, but with today's
> > current whatever goes out my vge interface (icmp/
> > tcp/udp) has bad checksum:
> 
> This is a FAQ; it's probably using hardware checksum offloading.
> 
> Since the packet passed down to the NIC does not yet have the checksum
> computed, it looks to tcpdump like the checksum is incorrect.  However
> if you look at the packet actually transmitted by the NIC
> (e.g. tcpdump on another host), you'll see that it has the correct
> checksum.
> 
Kris, you probably missed a commit by csjp@ where it was fixed.

: revision 1.220
: date: 2006/11/18 23:17:22;  author: csjp;  state: Exp;  lines: +40 -0
: Currently, drivers that support hardware offload of VLAN tag
: processing are forced to toggle this functionality when the card
: is put in and out of promiscuous mode.  The main reason for this
: is because the hardware strips the VLAN tag, making it impossible
: for the tag information to show up in network diagnostic tools like
: tcpdump(1).
: [...]

Andrey, have you been able to narrow your problem down to
either this commit, my vge(4) commit (though you tested it
as well before it was committed), or to FAST_IPSEC?


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