[PATCH] ipv6: judge the accept_ra_defrtr before calling rt6_route_rcv

[PATCH] ipv6: judge the accept_ra_defrtr before calling rt6_route_rcv

[Duan Jiong]

when dealing with a RA message, if accept_ra_defrtr is false,
the kernel will not add the default route, and then deal with
the following route information options. Unfortunately, those
options maybe contain default route, so let's judge the
accept_ra_defrtr before calling rt6_route_rcv.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
---
 net/ipv6/ndisc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 3512177..3008651 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1277,6 +1277,9 @@ skip_linkparms:
 			    ri->prefix_len == 0)
 				continue;
 #endif
+			if (ri->prefix_len == 0 &&
+			    !in6_dev->cnf.accept_ra_defrtr)
+				continue;
 			if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
 				continue;
 			rt6_route_rcv(skb->dev, (u8*)p, (p->nd_opt_len) << 3,
-- 
1.8.3.1

Re: [PATCH] ipv6: judge the accept_ra_defrtr before calling rt6_route_rcv

[Hannes Frederic Sowa]

On Tue, Nov 26, 2013 at 03:46:56PM +0800, Duan Jiong wrote:
> 
> when dealing with a RA message, if accept_ra_defrtr is false,
> the kernel will not add the default route, and then deal with
> the following route information options. Unfortunately, those
> options maybe contain default route, so let's judge the
> accept_ra_defrtr before calling rt6_route_rcv.
> 
> Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>

I am ambivalent regarding this change.

accept_ra_defrtr protected against adding default routers without routing
options and accept_ra_rt_info_max_plen == -1 disables the acceptance of any
routing options in router advertisments.

I don't have an idea why we need this distinction altough I once used it for
testing. But because this change makes it more understandable for users I am
ok with that.

Greetings,

  Hannes

Re: [PATCH] ipv6: judge the accept_ra_defrtr before calling rt6_route_rcv

[David Miller]

From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Fri, 29 Nov 2013 07:09:45 +0100

> On Tue, Nov 26, 2013 at 03:46:56PM +0800, Duan Jiong wrote:
>> 
>> when dealing with a RA message, if accept_ra_defrtr is false,
>> the kernel will not add the default route, and then deal with
>> the following route information options. Unfortunately, those
>> options maybe contain default route, so let's judge the
>> accept_ra_defrtr before calling rt6_route_rcv.
>> 
>> Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
> 
> I am ambivalent regarding this change.
> 
> accept_ra_defrtr protected against adding default routers without routing
> options and accept_ra_rt_info_max_plen == -1 disables the acceptance of any
> routing options in router advertisments.
> 
> I don't have an idea why we need this distinction altough I once used it for
> testing. But because this change makes it more understandable for users I am
> ok with that.

I've applied this, thanks everyone.