Re: [PATCH net-next] ipvlan: Make skb->skb_iif track skb->dev for l3s mode

[Jiri Pirko <jiri@resnulli.us>]

Thu, Mar 09, 2023 at 03:03:36AM CET, wujianguo106@163.com wrote:
>From: Jianguo Wu <wujianguo@chinatelecom.cn>
>
>For l3s mode, skb->dev is set to ipvlan interface in ipvlan_nf_input():
>  skb->dev = addr->master->dev
>but, skb->skb_iif remain unchanged, this will cause socket lookup failed
>if a target socket is bound to a interface, like the following example:
>
>  ip link add ipvlan0 link eth0 type ipvlan mode l3s
>  ip addr add dev ipvlan0 192.168.124.111/24
>  ip link set ipvlan0 up
>
>  ping -c 1 -I ipvlan0 8.8.8.8
>  100% packet loss
>
>This is because there is no match sk in __raw_v4_lookup() as sk->sk_bound_dev_if != dif(skb->skb_iif).
>Fix this by make skb->skb_iif track skb->dev in ipvlan_nf_input().
>
>Fixes: c675e06a98a4 ("ipvlan: decouple l3s mode dependencies from other modes").
>
>Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn>
>---
> drivers/net/ipvlan/ipvlan_l3s.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/drivers/net/ipvlan/ipvlan_l3s.c b/drivers/net/ipvlan/ipvlan_l3s.c
>index 943d26cbf39f..71712ea25403 100644
>--- a/drivers/net/ipvlan/ipvlan_l3s.c
>+++ b/drivers/net/ipvlan/ipvlan_l3s.c
>@@ -101,6 +101,7 @@ static unsigned int ipvlan_nf_input(void *priv, struct sk_buff *skb,
> 		goto out;
>
> 	skb->dev = addr->master->dev;
>+	skb->skb_iif = skb->dev->ifindex;

I think we should have a macro to replace skb->dev which would handle
this too. It's on multiple places.

Anyway, this patch looks fine to me.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>



> 	len = skb->len + ETH_HLEN;
> 	ipvlan_count_rx(addr->master, len, true, false);
> out:
>-- 
>1.8.3.1
>