[v2] net-ipv6: fix excessive RTF_ADDRCONF flag on ::1/128 local route (and others)
diff mbox series

Message ID 20190902162336.240405-1-zenczykowski@gmail.com
State Accepted
Delegated to: David Miller
Headers show
Series
  • [v2] net-ipv6: fix excessive RTF_ADDRCONF flag on ::1/128 local route (and others)
Related show

Commit Message

Maciej Żenczykowski Sept. 2, 2019, 4:23 p.m. UTC
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(-)

Comments

David Ahern Sept. 3, 2019, 2:14 a.m. UTC | #1
On 9/2/19 10:23 AM, Maciej Żenczykowski wrote:
> 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(-)
> 

Looks correct to me. Thanks for the patch.

Reviewed-by: David Ahern <dsahern@gmail.com>
David Miller Sept. 4, 2019, 10:33 p.m. UTC | #2
From: Maciej Żenczykowski <zenczykowski@gmail.com>
Date: Mon,  2 Sep 2019 09:23:36 -0700

> 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

Please format your Fixes: tag properly next time, I fixed it up for you.

> Cc: David Ahern <dsahern@gmail.com>
> Cc: Lorenzo Colitti <lorenzo@google.com>
> Signed-off-by: Maciej Żenczykowski <maze@google.com>

Applied and queued up for -stable.
Eric Dumazet Sept. 5, 2019, 6:49 p.m. UTC | #3
On 9/2/19 6:23 PM, Maciej Żenczykowski wrote:
> 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;

Shouldn't it use 

	if (!IS_ERR(f6i))
		f6i->dst_nocount = true;

???


> +	return f6i;
>  }
>  
>  /* remove deleted ip from prefsrc entries */
>
Maciej Żenczykowski Sept. 6, 2019, 3:31 a.m. UTC | #4
> Shouldn't it use
>
>         if (!IS_ERR(f6i))
>                 f6i->dst_nocount = true;
>
> ???

Yes, certainly.  I'll send a fix.

Patch
diff mbox series

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 */