Patch "net: ipv6: Compare lwstate in detecting duplicate nexthops" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    net: ipv6: Compare lwstate in detecting duplicate nexthops

to the 4.9-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:
     net-ipv6-compare-lwstate-in-detecting-duplicate-nexthops.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From f06b7549b79e29a672336d4e134524373fb7a232 Mon Sep 17 00:00:00 2001
From: David Ahern <dsahern@gmail.com>
Date: Wed, 5 Jul 2017 14:41:46 -0600
Subject: net: ipv6: Compare lwstate in detecting duplicate nexthops
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: David Ahern <dsahern@gmail.com>

commit f06b7549b79e29a672336d4e134524373fb7a232 upstream.

Lennert reported a failure to add different mpls encaps in a multipath
route:

  $ ip -6 route add 1234::/16 \
        nexthop encap mpls 10 via fe80::1 dev ens3 \
        nexthop encap mpls 20 via fe80::1 dev ens3
  RTNETLINK answers: File exists

The problem is that the duplicate nexthop detection does not compare
lwtunnel configuration. Add it.

Fixes: 19e42e451506 ("ipv6: support for fib route lwtunnel encap attributes")
Signed-off-by: David Ahern <dsahern@gmail.com>
Reported-by: João Taveira Araújo <joao.taveira@gmail.com>
Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Tested-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/net/ip6_route.h |    8 ++++++++
 net/ipv6/ip6_fib.c      |    5 +----
 net/ipv6/route.c        |    8 +-------
 3 files changed, 10 insertions(+), 11 deletions(-)

--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -22,6 +22,7 @@ struct route_info {
 #include <net/flow.h>
 #include <net/ip6_fib.h>
 #include <net/sock.h>
+#include <net/lwtunnel.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/route.h>
@@ -232,4 +233,11 @@ static inline struct in6_addr *rt6_nexth
 		return daddr;
 }
 
+static inline bool rt6_duplicate_nexthop(struct rt6_info *a, struct rt6_info *b)
+{
+	return a->dst.dev == b->dst.dev &&
+	       a->rt6i_idev == b->rt6i_idev &&
+	       ipv6_addr_equal(&a->rt6i_gateway, &b->rt6i_gateway) &&
+	       !lwtunnel_cmp_encap(a->dst.lwtstate, b->dst.lwtstate);
+}
 #endif
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -771,10 +771,7 @@ static int fib6_add_rt2node(struct fib6_
 				goto next_iter;
 			}
 
-			if (iter->dst.dev == rt->dst.dev &&
-			    iter->rt6i_idev == rt->rt6i_idev &&
-			    ipv6_addr_equal(&iter->rt6i_gateway,
-					    &rt->rt6i_gateway)) {
+			if (rt6_duplicate_nexthop(iter, rt)) {
 				if (rt->rt6i_nsiblings)
 					rt->rt6i_nsiblings = 0;
 				if (!(iter->rt6i_flags & RTF_EXPIRES))
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2953,17 +2953,11 @@ static int ip6_route_info_append(struct
 				 struct rt6_info *rt, struct fib6_config *r_cfg)
 {
 	struct rt6_nh *nh;
-	struct rt6_info *rtnh;
 	int err = -EEXIST;
 
 	list_for_each_entry(nh, rt6_nh_list, next) {
 		/* check if rt6_info already exists */
-		rtnh = nh->rt6_info;
-
-		if (rtnh->dst.dev == rt->dst.dev &&
-		    rtnh->rt6i_idev == rt->rt6i_idev &&
-		    ipv6_addr_equal(&rtnh->rt6i_gateway,
-				    &rt->rt6i_gateway))
+		if (rt6_duplicate_nexthop(nh->rt6_info, rt))
 			return err;
 	}
 


Patches currently in stable-queue which might be from dsahern@gmail.com are

queue-4.9/vrf-fix-bug_on-triggered-by-rx-when-destroying-a-vrf.patch
queue-4.9/ipv6-avoid-unregistering-inet6_dev-for-loopback.patch
queue-4.9/net-ipv6-compare-lwstate-in-detecting-duplicate-nexthops.patch