netdev - Re: [PATCH net] net/tunnel: set inner protocol in network gro hooks

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Date:   Tue, 7 Mar 2017 10:15:15 -0800
From:   Alexander Duyck <alexander.duyck@...il.com>
To:     Paolo Abeni <pabeni@...hat.com>
Cc:     Netdev <netdev@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Tom Herbert <tom@...bertland.com>
Subject: Re: [PATCH net] net/tunnel: set inner protocol in network gro hooks

On Tue, Mar 7, 2017 at 9:33 AM, Paolo Abeni <pabeni@...hat.com> wrote:
> The gso code of several tunnels type (gre and udp tunnels)
> takes for granted that the skb->inner_protocol is properly
> initialized and drops the packet elsewhere.
>
> On the forwarding path no one is initializing such field,
> so gro encapsulated packets are dropped on forward.
>
> Since commit 38720352412a ("gre: Use inner_proto to obtain
> inner header protocol"), this can be reproduced when the
> encapsulated packets use gre as the tunneling protocol.
>
> The issue happens also with vxlan and geneve tunnels since
> commit 8bce6d7d0d1e ("udp: Generalize skb_udp_segment"), if the
> forwarding host's ingress nic has h/w offload for such tunnel
> and a vxlan/geneve device is configured on top of it, regardless
> of the configured peer address and vni.
>
> To address the issue, this change initialize the inner_protocol
> field for encapsulated packets in both ipv4 and ipv6 gro complete
> callbacks.
>
> Fixes: 38720352412a ("gre: Use inner_proto to obtain inner header protocol")
> Fixes: 8bce6d7d0d1e ("udp: Generalize skb_udp_segment")
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Looks good to me.

Acked-by: Alexander Duyck <alexander.h.duyck@...el.com>

> ---
>  net/ipv4/af_inet.c     | 4 +++-
>  net/ipv6/ip6_offload.c | 4 +++-
>  2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index 602d40f..5091f46 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -1487,8 +1487,10 @@ int inet_gro_complete(struct sk_buff *skb, int nhoff)
>         int proto = iph->protocol;
>         int err = -ENOSYS;
>
> -       if (skb->encapsulation)
> +       if (skb->encapsulation) {
> +               skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IP));
>                 skb_set_inner_network_header(skb, nhoff);
> +       }
>
>         csum_replace2(&iph->check, iph->tot_len, newlen);
>         iph->tot_len = newlen;
> diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
> index 0838e6d..93e58a5 100644
> --- a/net/ipv6/ip6_offload.c
> +++ b/net/ipv6/ip6_offload.c
> @@ -294,8 +294,10 @@ static int ipv6_gro_complete(struct sk_buff *skb, int nhoff)
>         struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff);
>         int err = -ENOSYS;
>
> -       if (skb->encapsulation)
> +       if (skb->encapsulation) {
> +               skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IPV6));
>                 skb_set_inner_network_header(skb, nhoff);
> +       }
>
>         iph->payload_len = htons(skb->len - nhoff - sizeof(*iph));
>
> --
> 2.9.3
>