[PATCH net v2] ipv6: reallocate addrconf router for ipv6 address when lo device up

[PATCH net v2] ipv6: reallocate addrconf router for ipv6 address when lo device up

[Gao feng]

commit 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f
"net IPv6 : Fix broken IPv6 routing table after loopback down-up"
allocates addrconf router for ipv6 address when lo device up.
but commit a881ae1f625c599b460cc8f8a7fcb1c438f699ad
"ipv6:don't call addrconf_dst_alloc again when enable lo" breaks
this behavior.

Since the addrconf router is moved to the garbage list when
lo device down, we should release this router and rellocate
a new one for ipv6 address when lo device up.

This patch solves bug 67951 on bugzilla
https://bugzilla.kernel.org/show_bug.cgi?id=67951

change from v1:
use ip6_rt_put to repleace ip6_del_rt, thanks Hannes!
change code style, suggested by Sergei.

CC: Sabrina Dubroca <sd@queasysnail.net>
CC: Hannes Frederic Sowa <hannes@stressinduktion.org>
Reported-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
---
 net/ipv6/addrconf.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 4b6b720..dee84d6 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2611,8 +2611,18 @@ static void init_loopback(struct net_device *dev)
 			if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))
 				continue;
 
-			if (sp_ifa->rt)
-				continue;
+			if (sp_ifa->rt) {
+				/* This dst has been added to garbage list when
+				 * lo device down, release this obsolete dst and
+				 * reallocate a new router for ifa.
+				 */
+				if (sp_ifa->rt->dst.obsolete > 0) {
+					ip6_rt_put(sp_ifa->rt);
+					sp_ifa->rt = NULL;
+				} else {
+					continue;
+				}
+			}
 
 			sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, false);
 
-- 
1.8.4.2

Re: [PATCH net v2] ipv6: reallocate addrconf router for ipv6 address when lo device up

[Hannes Frederic Sowa]

On Fri, Jan 24, 2014 at 04:29:11PM +0800, Gao feng wrote:
> commit 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f
> "net IPv6 : Fix broken IPv6 routing table after loopback down-up"
> allocates addrconf router for ipv6 address when lo device up.
> but commit a881ae1f625c599b460cc8f8a7fcb1c438f699ad
> "ipv6:don't call addrconf_dst_alloc again when enable lo" breaks
> this behavior.
> 
> Since the addrconf router is moved to the garbage list when
> lo device down, we should release this router and rellocate
> a new one for ipv6 address when lo device up.
> 
> This patch solves bug 67951 on bugzilla
> https://bugzilla.kernel.org/show_bug.cgi?id=67951
> 
> change from v1:
> use ip6_rt_put to repleace ip6_del_rt, thanks Hannes!
> change code style, suggested by Sergei.
> 
> CC: Sabrina Dubroca <sd@queasysnail.net>
> CC: Hannes Frederic Sowa <hannes@stressinduktion.org>
> Reported-by: Weilong Chen <chenweilong@huawei.com>
> Signed-off-by: Weilong Chen <chenweilong@huawei.com>
> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>

Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

Thanks, Gao!

Re: [PATCH net v2] ipv6: reallocate addrconf router for ipv6 address when lo device up

[David Miller]

From: Gao feng <gaofeng@cn.fujitsu.com>
Date: Fri, 24 Jan 2014 16:29:11 +0800

> commit 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f
> "net IPv6 : Fix broken IPv6 routing table after loopback down-up"
> allocates addrconf router for ipv6 address when lo device up.
> but commit a881ae1f625c599b460cc8f8a7fcb1c438f699ad
> "ipv6:don't call addrconf_dst_alloc again when enable lo" breaks
> this behavior.
> 
> Since the addrconf router is moved to the garbage list when
> lo device down, we should release this router and rellocate
> a new one for ipv6 address when lo device up.
> 
> This patch solves bug 67951 on bugzilla
> https://bugzilla.kernel.org/show_bug.cgi?id=67951
> 
> change from v1:
> use ip6_rt_put to repleace ip6_del_rt, thanks Hannes!
> change code style, suggested by Sergei.
> 
> CC: Sabrina Dubroca <sd@queasysnail.net>
> CC: Hannes Frederic Sowa <hannes@stressinduktion.org>
> Reported-by: Weilong Chen <chenweilong@huawei.com>
> Signed-off-by: Weilong Chen <chenweilong@huawei.com>
> Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>

Applied and queued up for -stable, thanks!