Patch "ip6_tunnel: disable caching when the traffic class is inherited" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

ip6_tunnel: disable caching when the traffic class is inherited

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ip6_tunnel-disable-caching-when-the-traffic-class-is-inherited.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Paolo Abeni <[email protected]>
Date: Wed, 16 Nov 2016 16:26:46 +0100
Subject: ip6_tunnel: disable caching when the traffic class is inherited

From: Paolo Abeni <[email protected]>

[ Upstream commit b5c2d49544e5930c96e2632a7eece3f4325a1888 ]

If an ip6 tunnel is configured to inherit the traffic class from the inner header, the dst_cache must be disabled or it will foul the policy routing.

The issue is apprently there since at leat Linux-2.6.12-rc2.

---
 net/ipv6/ip6_tunnel.c |   13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

@@ -1014,6 +1014,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, st
 	int mtu;
 	unsigned int psh_hlen = sizeof(struct ipv6hdr) + t->encap_hlen;
 	unsigned int max_headroom = psh_hlen;
+	bool use_cache = false;
 	int err = -1;
 
 	/* NBMA tunnel */

@@ -1038,7 +1039,15 @@ int ip6_tnl_xmit(struct sk_buff *skb, st
 
 		memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
 		neigh_release(neigh);
-	} else if (!fl6->flowi6_mark)
+	} else if (!(t->parms.flags &
+		     (IP6_TNL_F_USE_ORIG_TCLASS | IP6_TNL_F_USE_ORIG_FWMARK))) {
+		/* enable the cache only only if the routing decision does
+		 * not depend on the current inner header value
+		 */
+		use_cache = true;
+	}
+
+	if (use_cache)
 		dst = dst_cache_get(&t->dst_cache);
 
 	if (!ip6_tnl_xmit_ctl(t, &fl6->saddr, &fl6->daddr))

@@ -1113,7 +1122,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, st
 		skb = new_skb;
 	}
 
-	if (!fl6->flowi6_mark && ndst)
+	if (use_cache && ndst)
 		dst_cache_set_ip6(&t->dst_cache, ndst, &fl6->saddr);
 	skb_dst_set(skb, dst);
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/ip6_tunnel-disable-caching-when-the-traffic-class-is-inherited.patch queue-4.8/ipv6-bump-genid-when-the-ifa_f_tentative-flag-is-clear.patch