net: ipv6: Don't purge default router if accept_ra=2

Setting net.ipv6.conf.<interface>.accept_ra=2 causes the kernel
to accept RAs even when forwarding is enabled. However, enabling
forwarding purges all default routes on the system, breaking
connectivity until the next RA is received. Fix this by not
purging default routes on interfaces that have accept_ra=2.

Signed-off-by: Lorenzo Colitti <lorenzo@google.com>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 928266569689..e5fe0041adfa 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1915,7 +1915,8 @@ void rt6_purge_dflt_routers(struct net *net)
 restart:
         read_lock_bh(&table->tb6_lock);
         for (rt = table->tb6_root.leaf; rt; rt = rt->dst.rt6_next) {
-                if (rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) {
+                if (rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF) &&
+                    (!rt->rt6i_idev || rt->rt6i_idev->cnf.accept_ra != 2)) {
                         dst_hold(&rt->dst);
                         read_unlock_bh(&table->tb6_lock);
                         ip6_del_rt(rt);