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>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 928266569689e7624cde4206f657df495a0bdd43..e5fe0041adfa389388060bffae7055db3508c407 100644 (file)
--- 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);