From: Ben Greear <greearb@candelatech.com>
To: Lewis Adam-CAL022 <Adam.Lewis@motorola.com>
Cc: netdev@oss.sgi.com
Subject: Re: hard_start_xmit and Linux bridging
Date: Thu, 09 Sep 2004 16:30:10 -0700 [thread overview]
Message-ID: <4140E782.2000505@candelatech.com> (raw)
In-Reply-To: <FD52892BD296D71183B400065BFCB6900EDB4C74@il02exm12>
Lewis Adam-CAL022 wrote:
> Hi all,
>
> I tried going to the bridge@lists.osdl.org for this question but got no response, I'm hoping somebody here has had a similar experience as me.
>
> Basically, I put my wlan0 driver in a bridge with eth0. When my hard_start_xmit() function is called (as a result of a packet received on eth0 and bridged to my driver), the skb that I am passed contains an extra four bytes (e.g. the Ethernet FCS).
>
> In my mind, this should be stripped off. But I have looked at all the open source net drivers I could find and nobody seems to care. Is there a way to know if the skb has been forwarded by a bridged interface? If I forward on the extra bytes, then a 1500 byte packet becomes 1504 and fails the MTU check on the other side of the wireless interface (when it is passed back to eth0).
>
> TIA,
> Adam
I added some ioctls to allow one to turn on the ability to receive the CRC, but I
don't know of any drivers that include it by default.
What driver/hardware is your eth0 device?
How are you determining the size, by the skb->len ?
Does tcpdump/ethereal show the extra 4 bytes if you sniff eth0 w/out bridging?
Ben
--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
next prev parent reply other threads:[~2004-09-09 23:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-09 22:10 hard_start_xmit and Linux bridging Lewis Adam-CAL022
2004-09-09 23:30 ` Ben Greear [this message]
-- strict thread matches above, loose matches on Subject: below --
2004-09-10 15:24 Lewis Adam-CAL022
2004-09-13 18:14 ` Ben Greear
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4140E782.2000505@candelatech.com \
--to=greearb@candelatech.com \
--cc=Adam.Lewis@motorola.com \
--cc=netdev@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).