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From: Eric Dumazet <eric.dumazet@gmail.com>
To: kaber@trash.net
Cc: netfilter-devel@vger.kernel.org, netdev@vger.kernel.org,
	ulrich.weber@sophos.com
Subject: Re: [PATCH 10/17] netfilter: ipv6: expand skb head in ip6_route_me_harder after oif change
Date: Mon, 21 Nov 2011 11:29:17 +0100	[thread overview]
Message-ID: <1321871357.2552.24.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> (raw)
In-Reply-To: <1321854369-3432-11-git-send-email-kaber@trash.net>

Le lundi 21 novembre 2011 à 06:46 +0100, kaber@trash.net a écrit :
> From: Patrick McHardy <kaber@trash.net>
> 
> Expand the skb headroom if the oif changed due to rerouting similar to
> how IPv4 packets are handled.
> 
> Signed-off-by: Patrick McHardy <kaber@trash.net>
> ---
>  net/ipv6/netfilter.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c
> index 30fcee4..d39e954 100644
> --- a/net/ipv6/netfilter.c
> +++ b/net/ipv6/netfilter.c
> @@ -14,6 +14,7 @@ int ip6_route_me_harder(struct sk_buff *skb)
>  {
>  	struct net *net = dev_net(skb_dst(skb)->dev);
>  	const struct ipv6hdr *iph = ipv6_hdr(skb);
> +	unsigned int hh_len;
>  	struct dst_entry *dst;
>  	struct flowi6 fl6 = {
>  		.flowi6_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
> @@ -46,6 +47,12 @@ int ip6_route_me_harder(struct sk_buff *skb)
>  	}
>  #endif
>  
> +	/* Change in oif may mean change in hh_len. */
> +	hh_len = skb_dst(skb)->dev->hard_header_len;
> +	if (skb_headroom(skb) < hh_len &&
> +	    pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC))
> +		return -1;
> +

Hmm, We had a problem recently on Tile arches because of unaligned
accesses.

Had you seen the bug report and proposed patch ?

Fix is to instead do :

	pskb_expand_head(skb,
			 HH_DATA_ALIGN(hh_len - skb_headroom(skb)), 
			 0,
			 GFP_ATOMIC);



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  reply	other threads:[~2011-11-21 10:29 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-21  5:45 [RFC PATCH 00/17] netfilter: IPv6 NAT kaber
2011-11-21  5:45 ` [PATCH 01/17] netfilter: nf_nat: use hash random for bysource hash kaber
2011-11-21  7:43   ` Eric Dumazet
2011-11-21  5:45 ` [PATCH 02/17] netfilter: nat: remove module reference counting from NAT protocols kaber
2011-11-21  7:36   ` Eric Dumazet
2011-11-21 14:59     ` Patrick McHardy
2011-11-21  5:45 ` [PATCH 03/17] netfilter: nf_nat: export NAT definitions to userspace kaber
2011-11-21  5:45 ` [PATCH 04/17] netfilter: nf_nat: remove obsolete code from nf_nat_icmp_reply_translation() kaber
2011-11-21  5:45 ` [PATCH 05/17] netfilter: nf_nat: remove obsolete check in nf_nat_mangle_udp_packet() kaber
2011-11-21  5:45 ` [PATCH 06/17] netfilter: ctnetlink: remove dead NAT code kaber
2011-11-21  5:45 ` [PATCH 07/17] netfilter: conntrack: restrict NAT helper invocation to IPv4 kaber
2011-11-21  5:46 ` [PATCH 08/17] netfilter: nf_nat: add protoff argument to packet mangling functions kaber
2011-11-21  5:46 ` [PATCH 09/17] netfilter: add protocol independant NAT core kaber
2011-11-21  5:46 ` [PATCH 10/17] netfilter: ipv6: expand skb head in ip6_route_me_harder after oif change kaber
2011-11-21 10:29   ` Eric Dumazet [this message]
2011-11-21 15:00     ` Patrick McHardy
2011-11-21  5:46 ` [PATCH 11/17] net: core: add function for incremental IPv6 pseudo header checksum updates kaber
2011-11-21  5:46 ` [PATCH 12/17] netfilter: ipv6: add IPv6 NAT support kaber
2011-11-21  5:46 ` [PATCH 13/17] netfilter: ip6tables: add MASQUERADE target kaber
2011-11-21  5:46 ` [PATCH 14/17] netfilter: ip6tables: add REDIRECT target kaber
2011-11-21  5:46 ` [PATCH 15/17] netfilter: ip6tables: add NETMAP target kaber
2011-11-21  5:46 ` [PATCH 16/17] netfilter: nf_nat: support IPv6 in FTP NAT helper kaber
2011-11-21  5:46 ` [PATCH 17/17] netfilter: nf_nat: support IPv6 in amanda " kaber
2011-11-21 13:05 ` [RFC PATCH 00/17] netfilter: IPv6 NAT Jan Engelhardt
2011-11-21 17:01   ` Patrick McHardy

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