netdev - Re: [PATCH net-next v4] vxlan: fix ND proxy when skb doesn't have transport header offset

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Date:   Mon, 03 Apr 2017 18:51:48 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     vincent@...nat.im
Cc:     edumazet@...gle.com, roopa@...ulusnetworks.com, jbenc@...hat.com,
        netdev@...r.kernel.org, xiyou.wangcong@...il.com
Subject: Re: [PATCH net-next v4] vxlan: fix ND proxy when skb doesn't have
 transport header offset

From: Vincent Bernat <vincent@...nat.im>
Date: Sun,  2 Apr 2017 11:00:06 +0200

> When an incoming frame is tagged or when GRO is disabled, the skb
> handled to vxlan_xmit() doesn't contain a valid transport header
> offset. This makes ND proxying fail.
> 
> We combine two changes: replace use of skb_transport_offset() and ensure
> the necessary amount of skb is linear just before using it:
> 
>  - In vxlan_xmit(), when determining if we have an ICMPv6 neighbor
>    discovery packet, just check if it is an ICMPv6 packet and rely on
>    neigh_reduce() to do more checks if this is the case. The use of
>    pskb_may_pull() is replaced by skb_header_pointer() for just the IPv6
>    header.
> 
>  - In neigh_reduce(), add pskb_may_pull() for IPv6 header and neighbor
>    discovery message since this was removed from vxlan_xmit(). Replace
>    skb_transport_header() with ipv6_hdr() + 1.
> 
>  - In vxlan_na_create(), replace first skb_transport_offset() with
>    ipv6_hdr() + 1 and second with skb_network_offset() + sizeof(struct
>    ipv6hdr). Additionally, ensure we pskb_may_pull() the whole skb as we
>    need it to iterate over the options.
> 
> Signed-off-by: Vincent Bernat <vincent@...nat.im>

Applied, thanks.