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From: "Maciej Żenczykowski" <zenczykowski@gmail.com>
To: "Maciej Żenczykowski" <maze@google.com>,
	"David S . Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org, David Ahern <dsahern@gmail.com>,
	Lorenzo Colitti <lorenzo@google.com>
Subject: [PATCH v2] net-ipv6: fix excessive RTF_ADDRCONF flag on ::1/128 local route (and others)
Date: Mon,  2 Sep 2019 09:23:36 -0700	[thread overview]
Message-ID: <20190902162336.240405-1-zenczykowski@gmail.com> (raw)
In-Reply-To: <565e386f-e72a-73db-1f34-fedb5190658a@gmail.com>

From: Maciej Żenczykowski <maze@google.com>

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: c7a1ce397adacaf5d4bb2eab0a738b5f80dc3e43
Cc: David Ahern <dsahern@gmail.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
 net/ipv6/route.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 558c6c68855f..516b2e568dae 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4365,13 +4365,14 @@ 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;
@@ -4381,7 +4382,10 @@ 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 */
-- 
2.23.0.187.g17f5b7556c-goog


  reply	other threads:[~2019-09-02 16:23 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-01 17:47 [PATCH] net-ipv6: fix excessive RTF_ADDRCONF flag on ::1/128 local route (and others) Maciej Żenczykowski
2019-09-01 17:55 ` Maciej Żenczykowski
2019-09-02  2:12   ` Lorenzo Colitti
2019-09-03  2:18     ` David Ahern
2019-09-03  4:58       ` Lorenzo Colitti
2019-09-03 12:17         ` Maciej Żenczykowski
2019-09-03 19:45           ` David Ahern
2019-09-04  3:17             ` Lorenzo Colitti
2019-09-02 13:37 ` David Ahern
2019-09-02 16:23   ` Maciej Żenczykowski [this message]
2019-09-03  2:14     ` [PATCH v2] " David Ahern
2019-09-04 22:33     ` David Miller
2019-09-05 18:49     ` Eric Dumazet
2019-09-06  3:31       ` Maciej Żenczykowski
2019-09-06  3:56         ` [PATCH] net-ipv6: addrconf_f6i_alloc - fix non-null pointer check to !IS_ERR() Maciej Żenczykowski
2019-09-06  5:10           ` Eric Dumazet
2019-09-07 15:48           ` David Miller

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