From 1e5dc146173251e7baad9a1f7586d5a009b6d9f9 Mon Sep 17 00:00:00 2001
From: Masahide NAKAMURA <nakam@linux-ipv6.org>
Date: Fri, 24 Aug 2007 19:08:55 +0900
Subject: [PATCH] [IPV6] IPSEC: Omit redirect for tunnelled packet.

IPv6 IPsec tunnel gateway incorrectly sends redirect to
router or sender when network device the IPsec tunnelled packet
is arrived is the same as the one the decapsulated packet
is sent.

With this patch, it omits to send the redirect when the forwarding
skbuff carries secpath, since such skbuff should be assumed as
a decapsulated packet from IPsec tunnel by own.

It may be a rare case for an IPsec security gateway, however
it is not rare when the gateway is MIPv6 Home Agent since
the another tunnel end-point is Mobile Node and it changes
the attached network.

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv6/ip6_output.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 26de3c0ea31e..e46d4683eab0 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -441,8 +441,10 @@ int ip6_forward(struct sk_buff *skb)
 
 	/* IPv6 specs say nothing about it, but it is clear that we cannot
 	   send redirects to source routed frames.
+	   We don't send redirects to frames decapsulated from IPsec.
 	 */
-	if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0) {
+	if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0 &&
+	    !skb->sp) {
 		struct in6_addr *target = NULL;
 		struct rt6_info *rt;
 		struct neighbour *n = dst->neighbour;
-- 
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