Changli Gao
2010-Dec-25 13:41 UTC
[Bridge] [PATCH] net: bridge: check the length of skb after nf_bridge_maybe_copy_header()
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 at gmail.com> --- net/bridge/br_forward.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c index 2bd11ec..ee64287 100644 --- a/net/bridge/br_forward.c +++ b/net/bridge/br_forward.c @@ -41,17 +41,13 @@ static inline unsigned packet_length(const struct sk_buff *skb) int br_dev_queue_push_xmit(struct sk_buff *skb) { - /* drop mtu oversized packets except gso */ - if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb)) + /* ip_fragment doesn't copy the MAC header */ + if (nf_bridge_maybe_copy_header(skb) || + (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))) { kfree_skb(skb); - else { - /* ip_fragment doesn't copy the MAC header */ - if (nf_bridge_maybe_copy_header(skb)) - kfree_skb(skb); - else { - skb_push(skb, ETH_HLEN); - dev_queue_xmit(skb); - } + } else { + skb_push(skb, ETH_HLEN); + dev_queue_xmit(skb); } return 0;
David Miller
2010-Dec-31 19:10 UTC
[Bridge] [PATCH] net: bridge: check the length of skb after nf_bridge_maybe_copy_header()
From: Changli Gao <xiaosuo at 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 at 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. Otherwise I suspect you have many other functions to fix as well. I'm not applying this patch.
Changli Gao
2011-Jan-03 10:44 UTC
[Bridge] [PATCH] net: bridge: check the length of skb after nf_bridge_maybe_copy_header()
On Sat, Jan 1, 2011 at 3:10 AM, David Miller <davem at davemloft.net> wrote:> From: Changli Gao <xiaosuo at 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 at 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. Please see this patch: http://git.kernel.org/?p=linux/kernel/git/davem/net-next-2.6.git;a=commitdiff;h=c893b8066c7bf6156e4d760e5acaf4c148e37190;hp=3c0fef0b7d36e5f8d3ea3731a8228102274e3c23> Otherwise I suspect you have many other functions to fix as well. > > I'm not applying this patch. >-- Regards, Changli Gao(xiaosuo at gmail.com)