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 6f9f7b63609ecf8c00db5517caaad2ba4cffde5f..5845613d3a30a10ae88bca0576fd42153036ae71 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1990,7 +1990,8 @@ 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);