1 files changed, 59 insertions, 48 deletions

diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 2c66b356025a..230645cc01c9 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -40,6 +40,7 @@
 #include <linux/igmp.h>
 #include <linux/kernel.h>
 #include <linux/workqueue.h>
+#include <linux/wait_bit.h>
 #include <linux/list.h>
 #include <net/sock.h>
 #include <net/ip.h>
@@ -89,17 +90,21 @@ struct udp_replicast {
 /**
  * struct udp_bearer - ip/udp bearer data structure
  * @bearer:	associated generic tipc bearer
- * @ubsock:	bearer associated socket
+ * @sk:		bearer associated socket
  * @ifindex:	local address scope
  * @work:	used to schedule deferred work on a bearer
  * @rcast:	associated udp_replicast container
+ * @rcast_lock:	serialize updates to @rcast.list against concurrent updaters
+ * @disabled:	bearer is being torn down; reject further @rcast.list additions
  */
 struct udp_bearer {
 	struct tipc_bearer __rcu *bearer;
-	struct socket *ubsock;
+	struct sock *sk;
 	u32 ifindex;
 	struct work_struct work;
 	struct udp_replicast rcast;
+	spinlock_t rcast_lock;
+	bool disabled;
 };
 
 static int tipc_udp_is_mcast_addr(struct udp_media_addr *addr)
@@ -194,7 +199,7 @@ static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
 		}
 
 		ttl = ip4_dst_hoplimit(&rt->dst);
-		udp_tunnel_xmit_skb(rt, ub->ubsock->sk, skb, src->ipv4.s_addr,
+		udp_tunnel_xmit_skb(rt, ub->sk, skb, src->ipv4.s_addr,
 				    dst->ipv4.s_addr, 0, ttl, 0, src->port,
 				    dst->port, false, true, 0);
 #if IS_ENABLED(CONFIG_IPV6)
@@ -206,7 +211,7 @@ static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
 				.saddr = src->ipv6,
 				.flowi6_proto = IPPROTO_UDP
 			};
-			ndst = ip6_dst_lookup_flow(net, ub->ubsock->sk,
+			ndst = ip6_dst_lookup_flow(net, ub->sk,
 						   &fl6, NULL);
 			if (IS_ERR(ndst)) {
 				err = PTR_ERR(ndst);
@@ -215,7 +220,7 @@ static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
 			dst_cache_set_ip6(cache, ndst, &fl6.saddr);
 		}
 		ttl = ip6_dst_hoplimit(ndst);
-		udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, skb, NULL,
+		udp_tunnel6_xmit_skb(ndst, ub->sk, skb, NULL,
 				     &src->ipv6, &dst->ipv6, 0, ttl, 0,
 				     src->port, dst->port, false, 0);
 #endif
@@ -277,26 +282,6 @@ out:
 	return err;
 }
 
-static bool tipc_udp_is_known_peer(struct tipc_bearer *b,
-				   struct udp_media_addr *addr)
-{
-	struct udp_replicast *rcast, *tmp;
-	struct udp_bearer *ub;
-
-	ub = rcu_dereference_rtnl(b->media_ptr);
-	if (!ub) {
-		pr_err_ratelimited("UDP bearer instance not found\n");
-		return false;
-	}
-
-	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
-		if (!memcmp(&rcast->addr, addr, sizeof(struct udp_media_addr)))
-			return true;
-	}
-
-	return false;
-}
-
 static int tipc_udp_rcast_add(struct tipc_bearer *b,
 			      struct udp_media_addr *addr)
 {
@@ -307,16 +292,34 @@ static int tipc_udp_rcast_add(struct tipc_bearer *b,
 	if (!ub)
 		return -ENODEV;
 
+	spin_lock_bh(&ub->rcast_lock);
+	if (ub->disabled) {
+		spin_unlock_bh(&ub->rcast_lock);
+		return 0;
+	}
+	list_for_each_entry(rcast, &ub->rcast.list, list) {
+		if (!memcmp(&rcast->addr, addr, sizeof(*addr))) {
+			spin_unlock_bh(&ub->rcast_lock);
+			return 0;
+		}
+	}
+
 	rcast = kmalloc_obj(*rcast, GFP_ATOMIC);
-	if (!rcast)
+	if (!rcast) {
+		spin_unlock_bh(&ub->rcast_lock);
 		return -ENOMEM;
+	}
 
 	if (dst_cache_init(&rcast->dst_cache, GFP_ATOMIC)) {
+		spin_unlock_bh(&ub->rcast_lock);
 		kfree(rcast);
 		return -ENOMEM;
 	}
 
 	memcpy(&rcast->addr, addr, sizeof(struct udp_media_addr));
+	list_add_rcu(&rcast->list, &ub->rcast.list);
+	b->bcast_addr.broadcast = TIPC_REPLICAST_SUPPORT;
+	spin_unlock_bh(&ub->rcast_lock);
 
 	if (ntohs(addr->proto) == ETH_P_IP)
 		pr_info("New replicast peer: %pI4\n", &rcast->addr.ipv4);
@@ -324,8 +327,6 @@ static int tipc_udp_rcast_add(struct tipc_bearer *b,
 	else if (ntohs(addr->proto) == ETH_P_IPV6)
 		pr_info("New replicast peer: %pI6\n", &rcast->addr.ipv6);
 #endif
-	b->bcast_addr.broadcast = TIPC_REPLICAST_SUPPORT;
-	list_add_rcu(&rcast->list, &ub->rcast.list);
 	return 0;
 }
 
@@ -360,9 +361,6 @@ static int tipc_udp_rcast_disc(struct tipc_bearer *b, struct sk_buff *skb)
 		return 0;
 	}
 
-	if (likely(tipc_udp_is_known_peer(b, &src)))
-		return 0;
-
 	return tipc_udp_rcast_add(b, &src);
 }
 
@@ -405,9 +403,9 @@ out:
 
 static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
 {
-	int err = 0;
+	struct sock *sk = ub->sk;
 	struct ip_mreqn mreqn;
-	struct sock *sk = ub->ubsock->sk;
+	int err = 0;
 
 	if (ntohs(remote->proto) == ETH_P_IP) {
 		mreqn.imr_multiaddr = remote->ipv4;
@@ -643,9 +641,6 @@ int tipc_udp_nl_bearer_add(struct tipc_bearer *b, struct nlattr *attr)
 		return -EINVAL;
 	}
 
-	if (tipc_udp_is_known_peer(b, &addr))
-		return 0;
-
 	return tipc_udp_rcast_add(b, &addr);
 }
 
@@ -670,6 +665,7 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 	struct nlattr *opts[TIPC_NLA_UDP_MAX + 1];
 	u8 node_id[NODE_ID_LEN] = {0,};
 	struct net_device *dev;
+	struct socket *sock;
 	int rmcast = 0;
 
 	ub = kzalloc_obj(*ub, GFP_ATOMIC);
@@ -677,6 +673,7 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 		return -ENOMEM;
 
 	INIT_LIST_HEAD(&ub->rcast.list);
+	spin_lock_init(&ub->rcast_lock);
 
 	if (!attrs[TIPC_NLA_BEARER_UDP_OPTS])
 		goto err;
@@ -764,14 +761,16 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 		goto err;
 	}
 	udp_conf.local_udp_port = local.port;
-	err = udp_sock_create(net, &udp_conf, &ub->ubsock);
+	err = udp_sock_create(net, &udp_conf, &sock);
 	if (err)
 		goto err;
+
+	ub->sk = sock->sk;
 	tuncfg.sk_user_data = ub;
 	tuncfg.encap_type = 1;
 	tuncfg.encap_rcv = tipc_udp_recv;
 	tuncfg.encap_destroy = NULL;
-	setup_udp_tunnel_sock(net, ub->ubsock, &tuncfg);
+	setup_udp_tunnel_sock(net, ub->sk, &tuncfg);
 
 	err = dst_cache_init(&ub->rcast.dst_cache, GFP_ATOMIC);
 	if (err)
@@ -793,12 +792,21 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 
 free:
 	dst_cache_destroy(&ub->rcast.dst_cache);
-	udp_tunnel_sock_release(ub->ubsock);
+	udp_tunnel_sock_release(ub->sk);
+	synchronize_rcu();
 err:
 	kfree(ub);
 	return err;
 }
 
+static void rcast_free_rcu(struct rcu_head *rcu)
+{
+	struct udp_replicast *rcast = container_of(rcu, struct udp_replicast, rcu);
+
+	dst_cache_destroy(&rcast->dst_cache);
+	kfree(rcast);
+}
+
 /* cleanup_bearer - break the socket/bearer association */
 static void cleanup_bearer(struct work_struct *work)
 {
@@ -806,20 +814,23 @@ static void cleanup_bearer(struct work_struct *work)
 	struct udp_replicast *rcast, *tmp;
 	struct tipc_net *tn;
 
+	spin_lock_bh(&ub->rcast_lock);
 	list_for_each_entry_safe(rcast, tmp, &ub->rcast.list, list) {
-		dst_cache_destroy(&rcast->dst_cache);
 		list_del_rcu(&rcast->list);
-		kfree_rcu(rcast, rcu);
+		call_rcu_hurry(&rcast->rcu, rcast_free_rcu);
 	}
+	ub->disabled = true;
+	spin_unlock_bh(&ub->rcast_lock);
 
-	tn = tipc_net(sock_net(ub->ubsock->sk));
+	tn = tipc_net(sock_net(ub->sk));
 
-	dst_cache_destroy(&ub->rcast.dst_cache);
-	udp_tunnel_sock_release(ub->ubsock);
+	udp_tunnel_sock_release(ub->sk);
 
-	/* Note: could use a call_rcu() to avoid another synchronize_net() */
 	synchronize_net();
-	atomic_dec(&tn->wq_count);
+
+	dst_cache_destroy(&ub->rcast.dst_cache);
+	if (atomic_dec_and_test(&tn->wq_count))
+		wake_up_var(&tn->wq_count);
 	kfree(ub);
 }
 
@@ -833,11 +844,11 @@ static void tipc_udp_disable(struct tipc_bearer *b)
 		pr_err("UDP bearer instance not found\n");
 		return;
 	}
-	sock_set_flag(ub->ubsock->sk, SOCK_DEAD);
+	sock_set_flag(ub->sk, SOCK_DEAD);
 	RCU_INIT_POINTER(ub->bearer, NULL);
 
 	/* sock_release need to be done outside of rtnl lock */
-	atomic_inc(&tipc_net(sock_net(ub->ubsock->sk))->wq_count);
+	atomic_inc(&tipc_net(sock_net(ub->sk))->wq_count);
 	INIT_WORK(&ub->work, cleanup_bearer);
 	schedule_work(&ub->work);
 }