Re: Adding support for VRF traffic passed by mangle table

[David Ahern <dsa@cumulusnetworks.com>]

On 4/2/17 10:57 PM, Jack Ma wrote:
> diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
> index c0cc6aa..07168d4 100644
> --- a/net/ipv4/netfilter.c
> +++ b/net/ipv4/netfilter.c
> @@ -46,6 +46,14 @@ int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_t
>                 fl4.flowi4_oif = l3mdev_master_ifindex(dev);

How does the above line (which is part of this block:
        fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0;
        if (!fl4.flowi4_oif)
                fl4.flowi4_oif = l3mdev_master_ifindex(dev);

) not work? The dst should be set on the skb at this point and the
device would reference the VRF.


>         fl4.flowi4_mark = skb->mark;
>         fl4.flowi4_flags = flags;
> +
> +       /* Since we have already known this is vrf flow passed by
> +        * mangle table, we wrap the oif with the master interface.
> +        */
> +       if (fl4.flowi4_oif == 0 && fl4.daddr && skb->dev &&
> +           netif_index_is_l3_master(net, skb->dev->ifindex))
> +               fl4.flowi4_oif = skb->dev->ifindex;
> +
>         rt = ip_route_output_key(net, &fl4);
>         if (IS_ERR(rt))
>                 return PTR_ERR(rt);
>