ip_tunnel: replace dst_cache with generic implementation

The current ip_tunnel cache implementation is prone to a race
that will cause the wrong dst to be cached on cuncurrent dst cache
miss and ip tunnel update via netlink.

Replacing with the generic implementation fix the issue.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 8 deletions

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 9a6b407f5840..0625ac6356b5 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -475,7 +475,7 @@ static void ipip6_tunnel_uninit(struct net_device *dev)
 		ipip6_tunnel_unlink(sitn, tunnel);
 		ipip6_tunnel_del_prl(tunnel, NULL);
 	}
-	ip_tunnel_dst_reset_all(tunnel);
+	dst_cache_reset(&tunnel->dst_cache);
 	dev_put(dev);
 }
 
@@ -1093,7 +1093,7 @@ static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
 		t->parms.link = p->link;
 		ipip6_tunnel_bind_dev(t->dev);
 	}
-	ip_tunnel_dst_reset_all(t);
+	dst_cache_reset(&t->dst_cache);
 	netdev_state_change(t->dev);
 }
 
@@ -1124,7 +1124,7 @@ static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
 	t->ip6rd.relay_prefix = relay_prefix;
 	t->ip6rd.prefixlen = ip6rd->prefixlen;
 	t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
-	ip_tunnel_dst_reset_all(t);
+	dst_cache_reset(&t->dst_cache);
 	netdev_state_change(t->dev);
 	return 0;
 }
@@ -1278,7 +1278,7 @@ ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 			err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
 			break;
 		}
-		ip_tunnel_dst_reset_all(t);
+		dst_cache_reset(&t->dst_cache);
 		netdev_state_change(dev);
 		break;
 
@@ -1339,7 +1339,7 @@ static void ipip6_dev_free(struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
 
-	free_percpu(tunnel->dst_cache);
+	dst_cache_destroy(&tunnel->dst_cache);
 	free_percpu(dev->tstats);
 	free_netdev(dev);
 }
@@ -1372,6 +1372,7 @@ static void ipip6_tunnel_setup(struct net_device *dev)
 static int ipip6_tunnel_init(struct net_device *dev)
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
+	int err;
 
 	tunnel->dev = dev;
 	tunnel->net = dev_net(dev);
@@ -1382,10 +1383,10 @@ static int ipip6_tunnel_init(struct net_device *dev)
 	if (!dev->tstats)
 		return -ENOMEM;
 
-	tunnel->dst_cache = alloc_percpu(struct ip_tunnel_dst);
-	if (!tunnel->dst_cache) {
+	err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
+	if (err) {
 		free_percpu(dev->tstats);
-		return -ENOMEM;
+		return err;
 	}
 
 	return 0;