ipv6: Fix route replacement with dev-only route (e404b8c7) · Commits · 戴 / test

After commit ("ipv6: fix ECMP route replacement") it is no longer possible to replace an ECMP-able route by a non ECMP-able route. For example, ip route add 2001:db8::1/128 via fe80::1 dev dummy0 ip route replace 2001:db8::1/128 dev dummy0 does not work as expected. Tweak the replacement logic so that point 3 in the log of the above commit becomes: 3. If the new route is not ECMP-able, and no matching non-ECMP-able route exists, replace matching ECMP-able route (if any) or add the new route. We can now summarize the entire replace semantics to: When doing a replace, prefer replacing a matching route of the same "ECMP-able-ness" as the replace argument. If there is no such candidate, fallback to the first route found. Fixes: ("ipv6: fix ECMP route replacement") Signed-off-by:

Benjamin Poirier <bpoirier@cumulusnetworks.com> Reviewed-by:

Michal Kubecek <mkubecek@suse.cz> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv6/ip6_fib.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -1102,7 +1102,6 @@ static int fib6_add_rt2node(struct fib6_node fn, struct fib6_info rt,
		found++;
		break;
		}
		if (rt_can_ecmp)
		fallback_ins = fallback_ins ?: ins;
		goto next_iter;
		}
		@@ -1146,7 +1145,9 @@ next_iter:
		}

		if (fallback_ins && !found) {
		/* No ECMP-able route found, replace first non-ECMP one */
		/* No matching route with same ecmp-able-ness found, replace
		* first matching route
		*/
		ins = fallback_ins;
		iter = rcu_dereference_protected(*ins,
		lockdep_is_held(&rt->fib6_table->tb6_lock));

tools/testing/selftests/net/fib_tests.sh

+6 −0

Original line number	Diff line number	Diff line
		@@ -910,6 +910,12 @@ ipv6_rt_replace_mpath()
		check_route6 "2001:db8:104::/64 via 2001:db8:101::3 dev veth1 metric 1024"
		log_test $? 0 "Multipath with single path via multipath attribute"

		# multipath with dev-only
		add_initial_route6 "nexthop via 2001:db8:101::2 nexthop via 2001:db8:103::2"
		run_cmd "$IP -6 ro replace 2001:db8:104::/64 dev veth1"
		check_route6 "2001:db8:104::/64 dev veth1 metric 1024"
		log_test $? 0 "Multipath with dev-only"

		# route replace fails - invalid nexthop 1
		add_initial_route6 "nexthop via 2001:db8:101::2 nexthop via 2001:db8:103::2"
		run_cmd "$IP -6 ro replace 2001:db8:104::/64 nexthop via 2001:db8:111::3 nexthop via 2001:db8:103::3"

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