[PATCH 3.10 13/16] ipv6: reallocate addrconf router for ipv6 address when lo device up

From: Greg Kroah-Hartman
Date: Sun Oct 12 2014 - 22:59:59 EST

3.10-stable review patch. If anyone has any objections, please let me know.


From: Gao feng <gaofeng@xxxxxxxxxxxxxx>

[ Upstream commit 33d99113b1102c2d2f8603b9ba72d89d915c13f5 ]

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

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

CC: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
CC: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Reported-by: Weilong Chen <chenweilong@xxxxxxxxxx>
Signed-off-by: Weilong Chen <chenweilong@xxxxxxxxxx>
Signed-off-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/ipv6/addrconf.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2691,8 +2691,18 @@ static void init_loopback(struct net_dev
if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))

- 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, 0);

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