Commit f06b7549 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

net: ipv6: Compare lwstate in detecting duplicate nexthops 



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: 19e42e45 ("ipv6: support for fib route lwtunnel encap attributes")
Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Reported-by: default avatarJoão Taveira Araújo <joao.taveira@gmail.com>
Reported-by: default avatarLennert Buytenhek <buytenh@wantstofly.org>
Acked-by: default avatarRoopa Prabhu <roopa@cumulusnetworks.com>
Tested-by: default avatarLennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 05a6b4ca

include/net/ip6_route.h

+8 −0
Original line number Diff line number Diff line
@@ -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_nexthop(struct rt6_info *rt, 
		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

net/ipv6/ip6_fib.c

+1 −4
Original line number Diff line number Diff line
@@ -786,10 +786,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, 
				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))

net/ipv6/route.c

+1 −7
Original line number Diff line number Diff line
@@ -3036,17 +3036,11 @@ static int ip6_route_info_append(struct list_head *rt6_nh_list, 
				 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;

	}

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