net-ipv6: fix excessive RTF_ADDRCONF flag on ::1/128 local route (and others)

[ Upstream commit d55a2e374a94fa34a3048c6a2be535266e506d97 ]

There is a subtle change in behaviour introduced by:
  commit c7a1ce397adacaf5d4bb2eab0a738b5f80dc3e43
  'ipv6: Change addrconf_f6i_alloc to use ip6_route_info_create'

Before that patch /proc/net/ipv6_route includes:
00000000000000000000000000000001 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000003 00000000 80200001 lo

Afterwards /proc/net/ipv6_route includes:
00000000000000000000000000000001 80 00000000000000000000000000000000 00 00000000000000000000000000000000 00000000 00000002 00000000 80240001 lo

ie. the above commit causes the ::1/128 local (automatic) route to be flagged with RTF_ADDRCONF (0x040000).

AFAICT, this is incorrect since these routes are *not* coming from RA's.

As such, this patch restores the old behaviour.

Fixes: c7a1ce397ada ("ipv6: Change addrconf_f6i_alloc to use ip6_route_info_create")
Cc: David Ahern <dsahern@gmail.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 5f5a0a42ce60fe5b645f28fee0243f3b6a76b4e2..97a350041f1899e6469c8b44898167ea36dd1935 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3841,13 +3841,14 @@ struct fib6_info *addrconf_f6i_alloc(struct net *net,
        struct fib6_config cfg = {
                .fc_table = l3mdev_fib_table(idev->dev) ? : RT6_TABLE_LOCAL,
                .fc_ifindex = idev->dev->ifindex,
-               .fc_flags = RTF_UP | RTF_ADDRCONF | RTF_NONEXTHOP,
+               .fc_flags = RTF_UP | RTF_NONEXTHOP,
                .fc_dst = *addr,
                .fc_dst_len = 128,
                .fc_protocol = RTPROT_KERNEL,
                .fc_nlinfo.nl_net = net,
                .fc_ignore_dev_down = true,
        };
+       struct fib6_info *f6i;
 
        if (anycast) {
                cfg.fc_type = RTN_ANYCAST;
@@ -3857,7 +3858,10 @@ struct fib6_info *addrconf_f6i_alloc(struct net *net,
                cfg.fc_flags |= RTF_LOCAL;
        }
 
-       return ip6_route_info_create(&cfg, gfp_flags, NULL);
+       f6i = ip6_route_info_create(&cfg, gfp_flags, NULL);
+       if (f6i)
+               f6i->dst_nocount = true;
+       return f6i;
 }
 
 /* remove deleted ip from prefsrc entries */