Re: [PATCH 1/1] reset nf before xmit vxlan encapsulated packet

From: Eric Dumazet
Date: Mon Mar 04 2013 - 10:24:10 EST


On Mon, 2013-03-04 at 22:08 +0800, Zang MingJie wrote:
> We should reset nf settings bond to the skb as ipip/ipgre do.
>
> If not, the conntrack/nat info bond to the origin packet may continually
> redirect the packet to vxlan interface causing a routing loop.
>
> this is the scenario:
>
> VETP VXLAN Gateway
> /----\ /---------------\
> | | | |
> | vx+--+vx --NAT-> eth0+--> Internet
> | | | |
> \----/ \---------------/
>
> when there are any packet coming from internet to the vetp, there will be lots
> of garbage packets coming out the gateway's vxlan interface, but none actually
> sent to the physical interface, because they are redirected back to the vxlan
> interface in the postrouting chain of NAT rule, and dmesg complains:
>
> Mar 1 21:52:53 debian kernel: [ 8802.997699] Dead loop on virtual device vxlan0, fix it urgently!
> Mar 1 21:52:54 debian kernel: [ 8804.004907] Dead loop on virtual device vxlan0, fix it urgently!
> Mar 1 21:52:55 debian kernel: [ 8805.012189] Dead loop on virtual device vxlan0, fix it urgently!
> Mar 1 21:52:56 debian kernel: [ 8806.020593] Dead loop on virtual device vxlan0, fix it urgently!
>
> the patch should fix the problem
>
> Signed-off-by: Zang MingJie <zealot0630@xxxxxxxxx>
> ---
> drivers/net/vxlan.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
> index f10e58a..c3e3d29 100644
> --- a/drivers/net/vxlan.c
> +++ b/drivers/net/vxlan.c
> @@ -961,6 +961,8 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
> iph->ttl = ttl ? : ip4_dst_hoplimit(&rt->dst);
> tunnel_ip_select_ident(skb, old_iph, &rt->dst);
>
> + nf_reset(skb);
> +
> vxlan_set_owner(dev, skb);
>
> /* See iptunnel_xmit() */


As mentioned in MAINTAINERS file, networking patches should be sent to :

M: "David S. Miller" <davem@xxxxxxxxxxxxx>
L: netdev@xxxxxxxxxxxxxxx

Thanks !


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