netdev - Re: [PATCH] ipv6: Fix protocol resubmission

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Message-ID: <5568C526.4060502@akamai.com>
Date:	Fri, 29 May 2015 14:59:34 -0500
From:	Josh Hunt <johunt@...mai.com>
To:	davem@...emloft.net
CC:	netdev@...r.kernel.org, tom@...bertland.com
Subject: Re: [PATCH] ipv6: Fix protocol resubmission

On 05/29/2015 02:56 PM, Josh Hunt wrote:
> I came across this problem while trying to use UDP encapsulation with IPv6. The
> change below fixes that, but it was not immediately apparent if there are any
> other protocols relying on this broken behavior. FWIW the behavior below now
> matches IPv4.
>
> Josh
> ---
>
> UDP encapsulation is broken on IPv6 because it expects when it returns a negative
> value that the packet will be resubmitted to the stack with the handler corresponding
> to the return value. The check currently looks for return values > 0 and then resubmits.
>
> This patch fixes that check and also moves the resubmit label to take advantage of
> the return code identifying the next protocol we want to process.
>
> Signed-off-by: Josh Hunt <johunt@...mai.com>
> ---
>   net/ipv6/ip6_input.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
> index f2e464e..a4c1026 100644
> --- a/net/ipv6/ip6_input.c
> +++ b/net/ipv6/ip6_input.c
> @@ -212,13 +212,13 @@ static int ip6_input_finish(struct sock *sk, struct sk_buff *skb)
>   	 */
>
>   	rcu_read_lock();
> -resubmit:
>   	idev = ip6_dst_idev(skb_dst(skb));
>   	if (!pskb_pull(skb, skb_transport_offset(skb)))
>   		goto discard;
>   	nhoff = IP6CB(skb)->nhoff;
>   	nexthdr = skb_network_header(skb)[nhoff];
>
> +resubmit:
>   	raw = raw6_local_deliver(skb, nexthdr);
>   	ipprot = rcu_dereference(inet6_protos[nexthdr]);
>   	if (ipprot) {
> @@ -246,7 +246,7 @@ resubmit:
>   			goto discard;
>
>   		ret = ipprot->handler(skb);
> -		if (ret > 0)
> +		if (ret < 0)
>   			goto resubmit;
>   		else if (ret == 0)
>   			IP6_INC_STATS_BH(net, idev, IPSTATS_MIB_INDELIVERS);
>

Please ignore, sending v2.

Josh
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