From: David Miller <davem@davemloft.net>
To: xiaosuo@gmail.com
Cc: shemminger@linux-foundation.org,
bridge@lists.linux-foundation.org, netdev@vger.kernel.org
Subject: Re: [PATCH] net: bridge: check the length of skb after nf_bridge_maybe_copy_header()
Date: Mon, 03 Jan 2011 09:22:14 -0800 (PST) [thread overview]
Message-ID: <20110103.092214.193706896.davem@davemloft.net> (raw)
In-Reply-To: <AANLkTingFk8qJ8tBwSRCxD=9k-0O3GnTv9V9TbF4N=bg@mail.gmail.com>
From: Changli Gao <xiaosuo@gmail.com>
Date: Mon, 3 Jan 2011 18:44:59 +0800
> On Sat, Jan 1, 2011 at 3:10 AM, David Miller <davem@davemloft.net> wrote:
>> From: Changli Gao <xiaosuo@gmail.com>
>> Date: Sat, 25 Dec 2010 21:41:30 +0800
>>
>>> Since nf_bridge_maybe_copy_header() may change the length of skb,
>>> we should check the length of skb after it to handle the ppoe skbs.
>>>
>>> Signed-off-by: Changli Gao <xiaosuo@gmail.com>
>>
>> This is really strange.
>>
>> packet_length() subtracts VLAN_HLEN from the value it returns, so the
>> correct fix seems to be to make this function handle the PPPOE case
>> too.
>>
>
> It is correct. The actual MTU of 802.1q frame is 4 bytes larger. For
> example, the MTU of ethernet is normally 1500, however the actual MTU
> of the 802.1Q is 1504.
Yes, I understand this, but I don't see why packet_length() cannot
simply account for PPPOE's encapsulation overhead just as it does for
VLAN's special MTU considerations.
next prev parent reply other threads:[~2011-01-03 17:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-25 13:41 [PATCH] net: bridge: check the length of skb after nf_bridge_maybe_copy_header() Changli Gao
2010-12-31 19:10 ` David Miller
2011-01-03 10:44 ` Changli Gao
2011-01-03 17:22 ` David Miller [this message]
2011-01-03 18:15 ` Stephen Hemminger
2011-01-03 20:13 ` David Miller
2011-01-05 13:37 ` Changli Gao
2011-01-06 19:33 ` David Miller
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