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

[ Upstream commit 3e8b0ac3e41e3c882222a5522d5df7212438ab51 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 493490f052a03702ecdcc35b8b94636ff9284d74..5a272c6520c5adf6a22230bb4a78dccdfd8d6c48 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1973,7 +1973,8 @@ 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);