tipc: let broadcast packet reception use new link receive function

The code path for receiving broadcast packets is currently distinct
from the unicast path. This leads to unnecessary code and data
duplication, something that can be avoided with some effort.

We now introduce separate per-peer tipc_link instances for handling
broadcast packet reception. Each receive link keeps a pointer to the
common, single, broadcast link instance, and can hence handle release
and retransmission of send buffers as if they belonged to the own
instance.

Furthermore, we let each unicast link instance keep a reference to both
the pertaining broadcast receive link, and to the common send link.
This makes it possible for the unicast links to easily access data for
broadcast link synchronization, as well as for carrying acknowledges for
received broadcast packets.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/tipc/bcast.c

@@ -112,11 +112,6 @@ static struct tipc_bc_base *tipc_bc_base(struct net *net)
 	return tipc_net(net)->bcbase;
 }
 
-static struct tipc_link *tipc_bc_sndlink(struct net *net)
-{
-	return tipc_net(net)->bcl;
-}
-
 /**
  * tipc_nmap_equal - test for equality of node maps
  */
@@ -169,31 +164,6 @@ static void bcbuf_decr_acks(struct sk_buff *buf)
 	bcbuf_set_acks(buf, bcbuf_acks(buf) - 1);
 }
 
-void tipc_bclink_add_node(struct net *net, u32 addr)
-{
-	struct tipc_net *tn = net_generic(net, tipc_net_id);
-	struct tipc_link *l = tipc_bc_sndlink(net);
-	tipc_bclink_lock(net);
-	tipc_nmap_add(&tn->bcbase->bcast_nodes, addr);
-	tipc_link_add_bc_peer(l);
-	tipc_bclink_unlock(net);
-}
-
-void tipc_bclink_remove_node(struct net *net, u32 addr)
-{
-	struct tipc_net *tn = net_generic(net, tipc_net_id);
-
-	tipc_bclink_lock(net);
-	tipc_nmap_remove(&tn->bcbase->bcast_nodes, addr);
-	tn->bcl->ackers--;
-
-	/* Last node? => reset backlog queue */
-	if (!tn->bcbase->bcast_nodes.count)
-		tipc_link_purge_backlog(tn->bcbase->link);
-
-	tipc_bclink_unlock(net);
-}
-
 static void bclink_set_last_sent(struct net *net)
 {
 	struct tipc_net *tn = net_generic(net, tipc_net_id);
@@ -501,12 +471,141 @@ int tipc_bcast_xmit(struct net *net, struct sk_buff_head *list)
 		__skb_queue_purge(&rcvq);
 		return rc;
 	}
+
 	/* Broadcast to all nodes, inluding local node */
 	tipc_bcbearer_xmit(net, &xmitq);
 	tipc_sk_mcast_rcv(net, &rcvq, &inputq);
 	__skb_queue_purge(list);
 	return 0;
 }
+
+/* tipc_bcast_rcv - receive a broadcast packet, and deliver to rcv link
+ *
+ * RCU is locked, no other locks set
+ */
+int tipc_bcast_rcv(struct net *net, struct tipc_link *l, struct sk_buff *skb)
+{
+	struct tipc_msg *hdr = buf_msg(skb);
+	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
+	struct sk_buff_head xmitq;
+	int rc;
+
+	__skb_queue_head_init(&xmitq);
+
+	if (msg_mc_netid(hdr) != tipc_netid(net) || !tipc_link_is_up(l)) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	tipc_bcast_lock(net);
+	if (msg_user(hdr) == BCAST_PROTOCOL)
+		rc = tipc_link_bc_nack_rcv(l, skb, &xmitq);
+	else
+		rc = tipc_link_rcv(l, skb, NULL);
+	tipc_bcast_unlock(net);
+
+	if (!skb_queue_empty(&xmitq))
+		tipc_bcbearer_xmit(net, &xmitq);
+
+	/* Any socket wakeup messages ? */
+	if (!skb_queue_empty(inputq))
+		tipc_sk_rcv(net, inputq);
+
+	return rc;
+}
+
+/* tipc_bcast_ack_rcv - receive and handle a broadcast acknowledge
+ *
+ * RCU is locked, no other locks set
+ */
+void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l, u32 acked)
+{
+	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
+	struct sk_buff_head xmitq;
+
+	__skb_queue_head_init(&xmitq);
+
+	tipc_bcast_lock(net);
+	tipc_link_bc_ack_rcv(l, acked, &xmitq);
+	tipc_bcast_unlock(net);
+
+	tipc_bcbearer_xmit(net, &xmitq);
+
+	/* Any socket wakeup messages ? */
+	if (!skb_queue_empty(inputq))
+		tipc_sk_rcv(net, inputq);
+}
+
+/* tipc_bcast_synch_rcv -  check and update rcv link with peer's send state
+ *
+ * RCU is locked, no other locks set
+ */
+void tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
+			 struct tipc_msg *hdr)
+{
+	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
+	struct sk_buff_head xmitq;
+
+	__skb_queue_head_init(&xmitq);
+
+	tipc_bcast_lock(net);
+	if (msg_type(hdr) == STATE_MSG) {
+		tipc_link_bc_ack_rcv(l, msg_bcast_ack(hdr), &xmitq);
+		tipc_link_bc_sync_rcv(l, hdr, &xmitq);
+	} else {
+		tipc_link_bc_init_rcv(l, hdr);
+	}
+	tipc_bcast_unlock(net);
+
+	tipc_bcbearer_xmit(net, &xmitq);
+
+	/* Any socket wakeup messages ? */
+	if (!skb_queue_empty(inputq))
+		tipc_sk_rcv(net, inputq);
+}
+
+/* tipc_bcast_add_peer - add a peer node to broadcast link and bearer
+ *
+ * RCU is locked, node lock is set
+ */
+void tipc_bcast_add_peer(struct net *net, u32 addr, struct tipc_link *uc_l,
+			 struct sk_buff_head *xmitq)
+{
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+	struct tipc_link *snd_l = tipc_bc_sndlink(net);
+
+	tipc_bclink_lock(net);
+	tipc_nmap_add(&tn->bcbase->bcast_nodes, addr);
+	tipc_link_add_bc_peer(snd_l, uc_l, xmitq);
+	tipc_bclink_unlock(net);
+}
+
+/* tipc_bcast_remove_peer - remove a peer node from broadcast link and bearer
+ *
+ * RCU is locked, node lock is set
+ */
+void tipc_bcast_remove_peer(struct net *net, u32 addr,
+			    struct tipc_link *rcv_l)
+{
+	struct tipc_net *tn = net_generic(net, tipc_net_id);
+	struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
+	struct tipc_link *snd_l = tipc_bc_sndlink(net);
+	struct sk_buff_head xmitq;
+
+	__skb_queue_head_init(&xmitq);
+
+	tipc_bclink_lock(net);
+	tipc_nmap_remove(&tn->bcbase->bcast_nodes, addr);
+	tipc_link_remove_bc_peer(snd_l, rcv_l, &xmitq);
+	tipc_bclink_unlock(net);
+
+	tipc_bcbearer_xmit(net, &xmitq);
+
+	/* Any socket wakeup messages ? */
+	if (!skb_queue_empty(inputq))
+		tipc_sk_rcv(net, inputq);
+}
+
 /**
  * bclink_accept_pkt - accept an incoming, in-sequence broadcast packet
  *
@@ -728,6 +827,7 @@ static int tipc_bcbearer_send(struct net *net, struct sk_buff *buf,
 			return 0;
 		}
 	}
+	msg_set_mc_netid(msg, tn->net_id);
 
 	/* Send buffer over bearers until all targets reached */
 	bcbearer->remains = bclink->bcast_nodes;
@@ -1042,12 +1142,13 @@ int tipc_bcast_init(struct net *net)
 	spin_lock_init(&tipc_net(net)->bclock);
 	bb->node.net = net;
 
-	if (!tipc_link_bc_create(&bb->node,
+	if (!tipc_link_bc_create(&bb->node, 0, 0,
 				 MAX_PKT_DEFAULT_MCAST,
 				 BCLINK_WIN_DEFAULT,
 				 0,
 				 &bb->inputq,
 				 &bb->namedq,
+				 NULL,
 				 &l))
 		goto enomem;
 	bb->link = l;

net/tipc/bcast.h

@@ -47,8 +47,11 @@ struct tipc_node_map;
 int tipc_bcast_init(struct net *net);
 void tipc_bcast_reinit(struct net *net);
 void tipc_bcast_stop(struct net *net);
-void tipc_bclink_add_node(struct net *net, u32 addr);
-void tipc_bclink_remove_node(struct net *net, u32 addr);
+void tipc_bcast_add_peer(struct net *net, u32 addr,
+			 struct tipc_link *l,
+			 struct sk_buff_head *xmitq);
+void tipc_bcast_remove_peer(struct net *net, u32 addr,
+			    struct tipc_link *rcv_bcl);
 struct tipc_node *tipc_bclink_retransmit_to(struct net *tn);
 void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked);
 void tipc_bclink_rcv(struct net *net, struct sk_buff *buf);
@@ -62,6 +65,10 @@ int  tipc_bclink_reset_stats(struct net *net);
 int  tipc_bclink_set_queue_limits(struct net *net, u32 limit);
 uint  tipc_bcast_get_mtu(void);
 int tipc_bcast_xmit(struct net *net, struct sk_buff_head *list);
+int tipc_bcast_rcv(struct net *net, struct tipc_link *l, struct sk_buff *skb);
+void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l, u32 acked);
+void tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
+			 struct tipc_msg *hdr);
 void tipc_bclink_wakeup_users(struct net *net);
 int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg);
 int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[]);
@@ -78,4 +85,9 @@ static inline void tipc_bcast_unlock(struct net *net)
 	spin_unlock_bh(&tipc_net(net)->bclock);
 }
 
+static inline struct tipc_link *tipc_bc_sndlink(struct net *net)
+{
+	return tipc_net(net)->bcl;
+}
+
 #endif

net/tipc/core.h

@@ -115,6 +115,11 @@ static inline struct tipc_net *tipc_net(struct net *net)
 	return net_generic(net, tipc_net_id);
 }
 
+static inline int tipc_netid(struct net *net)
+{
+	return tipc_net(net)->net_id;
+}
+
 static inline u16 mod(u16 x)
 {
 	return x & 0xffffu;

net/tipc/link.h

@@ -66,7 +66,8 @@ enum {
  */
 enum {
 	TIPC_LINK_UP_EVT       = 1,
-	TIPC_LINK_DOWN_EVT     = (1 << 1)
+	TIPC_LINK_DOWN_EVT     = (1 << 1),
+	TIPC_LINK_SND_BC_ACK   = (1 << 2)
 };
 
 /* Starting value for maximum packet size negotiation on unicast links
@@ -209,6 +210,10 @@ struct tipc_link {
 	/* Broadcast */
 	u16 ackers;
 	u16 acked;
+	struct tipc_link *bc_rcvlink;
+	struct tipc_link *bc_sndlink;
+	int nack_state;
+	bool bc_peer_is_up;
 
 	/* Statistics */
 	struct tipc_stats stats;
@@ -217,17 +222,21 @@ struct tipc_link {
 bool tipc_link_create(struct tipc_node *n, char *if_name, int bearer_id,
 		      int tolerance, char net_plane, u32 mtu, int priority,
 		      int window, u32 session, u32 ownnode, u32 peer,
-		      u16 peer_caps, struct tipc_media_addr *maddr,
-		      struct sk_buff_head *inputq, struct sk_buff_head *namedq,
+		      u16 peer_caps,
+		      struct tipc_media_addr *maddr,
+		      struct tipc_link *bc_sndlink,
+		      struct tipc_link *bc_rcvlink,
+		      struct sk_buff_head *inputq,
+		      struct sk_buff_head *namedq,
 		      struct tipc_link **link);
-bool tipc_link_bc_create(struct tipc_node *n, int mtu, int window,
-			 u16 peer_caps, struct sk_buff_head *inputq,
+bool tipc_link_bc_create(struct tipc_node *n, u32 ownnode, u32 peer,
+			 int mtu, int window, u16 peer_caps,
+			 struct sk_buff_head *inputq,
 			 struct sk_buff_head *namedq,
+			 struct tipc_link *bc_sndlink,
 			 struct tipc_link **link);
 void tipc_link_tnl_prepare(struct tipc_link *l, struct tipc_link *tnl,
 			   int mtyp, struct sk_buff_head *xmitq);
-void tipc_link_build_bcast_sync_msg(struct tipc_link *l,
-				    struct sk_buff_head *xmitq);
 void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
 int tipc_link_fsm_evt(struct tipc_link *l, int evt);
 void tipc_link_reset_fragments(struct tipc_link *l_ptr);
@@ -264,9 +273,21 @@ int tipc_nl_parse_link_prop(struct nlattr *prop, struct nlattr *props[]);
 int tipc_link_timeout(struct tipc_link *l, struct sk_buff_head *xmitq);
 int tipc_link_rcv(struct tipc_link *l, struct sk_buff *skb,
 		  struct sk_buff_head *xmitq);
-void tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
-void tipc_link_add_bc_peer(struct tipc_link *l);
-void tipc_link_remove_bc_peer(struct tipc_link *l);
+int tipc_link_build_ack_msg(struct tipc_link *l, struct sk_buff_head *xmitq);
+void tipc_link_add_bc_peer(struct tipc_link *snd_l,
+			   struct tipc_link *uc_l,
+			   struct sk_buff_head *xmitq);
+void tipc_link_remove_bc_peer(struct tipc_link *snd_l,
+			      struct tipc_link *rcv_l,
+			      struct sk_buff_head *xmitq);
 int tipc_link_bc_peers(struct tipc_link *l);
-
+void tipc_link_bc_ack_rcv(struct tipc_link *l, u16 acked,
+			  struct sk_buff_head *xmitq);
+void tipc_link_build_bc_sync_msg(struct tipc_link *l,
+				 struct sk_buff_head *xmitq);
+void tipc_link_bc_init_rcv(struct tipc_link *l, struct tipc_msg *hdr);
+void tipc_link_bc_sync_rcv(struct tipc_link *l,   struct tipc_msg *hdr,
+			   struct sk_buff_head *xmitq);
+int tipc_link_bc_nack_rcv(struct tipc_link *l, struct sk_buff *skb,
+			  struct sk_buff_head *xmitq);
 #endif

net/tipc/msg.c

@@ -182,7 +182,6 @@ int tipc_buf_append(struct sk_buff **headbuf, struct sk_buff **buf)
 	*buf = NULL;
 	return 0;
 err:
-	pr_warn_ratelimited("Unable to build fragment list\n");
 	kfree_skb(*buf);
 	kfree_skb(*headbuf);
 	*buf = *headbuf = NULL;

net/tipc/msg.h

@@ -601,6 +601,11 @@ static inline u32 msg_last_bcast(struct tipc_msg *m)
 	return msg_bits(m, 4, 16, 0xffff);
 }
 
+static inline u32 msg_bc_snd_nxt(struct tipc_msg *m)
+{
+	return msg_last_bcast(m) + 1;
+}
+
 static inline void msg_set_last_bcast(struct tipc_msg *m, u32 n)
 {
 	msg_set_bits(m, 4, 16, 0xffff, n);

net/tipc/node.c

@@ -72,7 +72,6 @@ static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id,
 static void tipc_node_link_down(struct tipc_node *n, int bearer_id,
 				bool delete);
 static void node_lost_contact(struct tipc_node *n, struct sk_buff_head *inputq);
-static void node_established_contact(struct tipc_node *n_ptr);
 static void tipc_node_delete(struct tipc_node *node);
 static void tipc_node_timeout(unsigned long data);
 static void tipc_node_fsm_evt(struct tipc_node *n, int evt);
@@ -165,8 +164,10 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
 	INIT_LIST_HEAD(&n_ptr->list);
 	INIT_LIST_HEAD(&n_ptr->publ_list);
 	INIT_LIST_HEAD(&n_ptr->conn_sks);
-	skb_queue_head_init(&n_ptr->bclink.namedq);
-	__skb_queue_head_init(&n_ptr->bclink.deferdq);
+	skb_queue_head_init(&n_ptr->bc_entry.namedq);
+	skb_queue_head_init(&n_ptr->bc_entry.inputq1);
+	__skb_queue_head_init(&n_ptr->bc_entry.arrvq);
+	skb_queue_head_init(&n_ptr->bc_entry.inputq2);
 	hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
 	list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
 		if (n_ptr->addr < temp_node->addr)
@@ -177,6 +178,18 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr, u16 capabilities)
 	n_ptr->signature = INVALID_NODE_SIG;
 	n_ptr->active_links[0] = INVALID_BEARER_ID;
 	n_ptr->active_links[1] = INVALID_BEARER_ID;
+	if (!tipc_link_bc_create(n_ptr, tipc_own_addr(net), n_ptr->addr,
+				 U16_MAX, tipc_bc_sndlink(net)->window,
+				 n_ptr->capabilities,
+				 &n_ptr->bc_entry.inputq1,
+				 &n_ptr->bc_entry.namedq,
+				 tipc_bc_sndlink(net),
+				 &n_ptr->bc_entry.link)) {
+		pr_warn("Broadcast rcv link creation failed, no memory\n");
+		kfree(n_ptr);
+		n_ptr = NULL;
+		goto exit;
+	}
 	tipc_node_get(n_ptr);
 	setup_timer(&n_ptr->timer, tipc_node_timeout, (unsigned long)n_ptr);
 	n_ptr->keepalive_intv = U32_MAX;
@@ -203,6 +216,7 @@ static void tipc_node_delete(struct tipc_node *node)
 {
 	list_del_rcu(&node->list);
 	hlist_del_rcu(&node->hash);
+	kfree(node->bc_entry.link);
 	kfree_rcu(node, rcu);
 }
 
@@ -340,8 +354,9 @@ static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
 	if (!ol) {
 		*slot0 = bearer_id;
 		*slot1 = bearer_id;
-		tipc_link_build_bcast_sync_msg(nl, xmitq);
-		node_established_contact(n);
+		tipc_node_fsm_evt(n, SELF_ESTABL_CONTACT_EVT);
+		n->action_flags |= TIPC_NOTIFY_NODE_UP;
+		tipc_bcast_add_peer(n->net, n->addr, nl, xmitq);
 		return;
 	}
 
@@ -585,9 +600,10 @@ void tipc_node_check_dest(struct net *net, u32 onode,
 				      b->net_plane, b->mtu, b->priority,
 				      b->window, mod(tipc_net(net)->random),
 				      tipc_own_addr(net), onode,
-				      n->capabilities,
-				      &le->maddr, &le->inputq,
-				      &n->bclink.namedq, &l)) {
+				      n->capabilities, &le->maddr,
+				      tipc_bc_sndlink(n->net), n->bc_entry.link,
+				      &le->inputq,
+				      &n->bc_entry.namedq, &l)) {
 			*respond = false;
 			goto exit;
 		}
@@ -830,58 +846,36 @@ bool tipc_node_filter_pkt(struct tipc_node *n, struct tipc_msg *hdr)
 	return true;
 }
 
-static void node_established_contact(struct tipc_node *n_ptr)
-{
-	tipc_node_fsm_evt(n_ptr, SELF_ESTABL_CONTACT_EVT);
-	n_ptr->action_flags |= TIPC_NOTIFY_NODE_UP;
-	n_ptr->bclink.oos_state = 0;
-	n_ptr->bclink.acked = tipc_bclink_get_last_sent(n_ptr->net);
-	tipc_bclink_add_node(n_ptr->net, n_ptr->addr);
-}
-
-static void node_lost_contact(struct tipc_node *n_ptr,
+static void node_lost_contact(struct tipc_node *n,
 			      struct sk_buff_head *inputq)
 {
 	char addr_string[16];
 	struct tipc_sock_conn *conn, *safe;
 	struct tipc_link *l;
-	struct list_head *conns = &n_ptr->conn_sks;
+	struct list_head *conns = &n->conn_sks;
 	struct sk_buff *skb;
-	struct tipc_net *tn = net_generic(n_ptr->net, tipc_net_id);
 	uint i;
 
 	pr_debug("Lost contact with %s\n",
-		 tipc_addr_string_fill(addr_string, n_ptr->addr));
-
-	/* Flush broadcast link info associated with lost node */
-	if (n_ptr->bclink.recv_permitted) {
-		__skb_queue_purge(&n_ptr->bclink.deferdq);
+		 tipc_addr_string_fill(addr_string, n->addr));
 
-		if (n_ptr->bclink.reasm_buf) {
-			kfree_skb(n_ptr->bclink.reasm_buf);
-			n_ptr->bclink.reasm_buf = NULL;
-		}
-
-		tipc_bclink_remove_node(n_ptr->net, n_ptr->addr);
-		tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);
-
-		n_ptr->bclink.recv_permitted = false;
-	}
+	/* Clean up broadcast state */
+	tipc_bcast_remove_peer(n->net, n->addr, n->bc_entry.link);
 
 	/* Abort any ongoing link failover */
 	for (i = 0; i < MAX_BEARERS; i++) {
-		l = n_ptr->links[i].link;
+		l = n->links[i].link;
 		if (l)
 			tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);
 	}
 
 	/* Notify publications from this node */
-	n_ptr->action_flags |= TIPC_NOTIFY_NODE_DOWN;
+	n->action_flags |= TIPC_NOTIFY_NODE_DOWN;
 
 	/* Notify sockets connected to node */
 	list_for_each_entry_safe(conn, safe, conns, list) {
 		skb = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
-				      SHORT_H_SIZE, 0, tn->own_addr,
+				      SHORT_H_SIZE, 0, tipc_own_addr(n->net),
 				      conn->peer_node, conn->port,
 				      conn->peer_port, TIPC_ERR_NO_NODE);
 		if (likely(skb))
@@ -1085,6 +1079,67 @@ int tipc_node_xmit_skb(struct net *net, struct sk_buff *skb, u32 dnode,
 	return 0;
 }
 
+/**
+ * tipc_node_bc_rcv - process TIPC broadcast packet arriving from off-node
+ * @net: the applicable net namespace
+ * @skb: TIPC packet
+ * @bearer_id: id of bearer message arrived on
+ *
+ * Invoked with no locks held.
+ */
+void tipc_node_bc_rcv(struct net *net, struct sk_buff *skb, int bearer_id)
+{
+	int rc;
+	struct sk_buff_head xmitq;
+	struct tipc_bclink_entry *be;
+	struct tipc_link_entry *le;
+	struct tipc_msg *hdr = buf_msg(skb);
+	int usr = msg_user(hdr);
+	u32 dnode = msg_destnode(hdr);
+	struct tipc_node *n;
+
+	__skb_queue_head_init(&xmitq);
+
+	/* If NACK for other node, let rcv link for that node peek into it */
+	if ((usr == BCAST_PROTOCOL) && (dnode != tipc_own_addr(net)))
+		n = tipc_node_find(net, dnode);
+	else
+		n = tipc_node_find(net, msg_prevnode(hdr));
+	if (!n) {
+		kfree_skb(skb);
+		return;
+	}
+	be = &n->bc_entry;
+	le = &n->links[bearer_id];
+
+	rc = tipc_bcast_rcv(net, be->link, skb);
+
+	/* Broadcast link reset may happen at reassembly failure */
+	if (rc & TIPC_LINK_DOWN_EVT)
+		tipc_node_reset_links(n);
+
+	/* Broadcast ACKs are sent on a unicast link */
+	if (rc & TIPC_LINK_SND_BC_ACK) {
+		tipc_node_lock(n);
+		tipc_link_build_ack_msg(le->link, &xmitq);
+		tipc_node_unlock(n);
+	}
+
+	if (!skb_queue_empty(&xmitq))
+		tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
+
+	/* Deliver. 'arrvq' is under inputq2's lock protection */
+	if (!skb_queue_empty(&be->inputq1)) {
+		spin_lock_bh(&be->inputq2.lock);
+		spin_lock_bh(&be->inputq1.lock);
+		skb_queue_splice_tail_init(&be->inputq1, &be->arrvq);
+		spin_unlock_bh(&be->inputq1.lock);
+		spin_unlock_bh(&be->inputq2.lock);
+		tipc_sk_mcast_rcv(net, &be->arrvq, &be->inputq2);
+	}
+	tipc_node_put(n);
+}
+
 /**
  * tipc_node_check_state - check and if necessary update node state
  * @skb: TIPC packet
@@ -1227,6 +1282,7 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 	int usr = msg_user(hdr);
 	int bearer_id = b->identity;
 	struct tipc_link_entry *le;
+	u16 bc_ack = msg_bcast_ack(hdr);
 	int rc = 0;
 
 	__skb_queue_head_init(&xmitq);
@@ -1235,13 +1291,12 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 	if (unlikely(!tipc_msg_validate(skb)))
 		goto discard;
 
-	/* Handle arrival of a non-unicast link packet */
+	/* Handle arrival of discovery or broadcast packet */
 	if (unlikely(msg_non_seq(hdr))) {
-		if (usr ==  LINK_CONFIG)
-			tipc_disc_rcv(net, skb, b);
+		if (unlikely(usr == LINK_CONFIG))
+			return tipc_disc_rcv(net, skb, b);
 		else
-			tipc_bclink_rcv(net, skb);
-		return;
+			return tipc_node_bc_rcv(net, skb, bearer_id);
 	}
 
 	/* Locate neighboring node that sent packet */
@@ -1250,19 +1305,18 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 		goto discard;
 	le = &n->links[bearer_id];
 
+	/* Ensure broadcast reception is in synch with peer's send state */
+	if (unlikely(usr == LINK_PROTOCOL))
+		tipc_bcast_sync_rcv(net, n->bc_entry.link, hdr);
+	else if (unlikely(n->bc_entry.link->acked != bc_ack))
+		tipc_bcast_ack_rcv(net, n->bc_entry.link, bc_ack);
+
 	tipc_node_lock(n);
 
 	/* Is reception permitted at the moment ? */
 	if (!tipc_node_filter_pkt(n, hdr))
 		goto unlock;
 
-	if (unlikely(msg_user(hdr) == LINK_PROTOCOL))
-		tipc_bclink_sync_state(n, hdr);
-
-	/* Release acked broadcast packets */
-	if (unlikely(n->bclink.acked != msg_bcast_ack(hdr)))
-		tipc_bclink_acknowledge(n, msg_bcast_ack(hdr));
-
 	/* Check and if necessary update node state */
 	if (likely(tipc_node_check_state(n, skb, bearer_id, &xmitq))) {
 		rc = tipc_link_rcv(le->link, skb, &xmitq);
@@ -1277,8 +1331,8 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 	if (unlikely(rc & TIPC_LINK_DOWN_EVT))
 		tipc_node_link_down(n, bearer_id, false);
 
-	if (unlikely(!skb_queue_empty(&n->bclink.namedq)))
-		tipc_named_rcv(net, &n->bclink.namedq);
+	if (unlikely(!skb_queue_empty(&n->bc_entry.namedq)))
+		tipc_named_rcv(net, &n->bc_entry.namedq);
 
 	if (!skb_queue_empty(&le->inputq))
 		tipc_sk_rcv(net, &le->inputq);

net/tipc/node.h

@@ -100,6 +100,14 @@ struct tipc_link_entry {
 	struct tipc_media_addr maddr;
 };
 
+struct tipc_bclink_entry {
+	struct tipc_link *link;
+	struct sk_buff_head inputq1;
+	struct sk_buff_head arrvq;
+	struct sk_buff_head inputq2;
+	struct sk_buff_head namedq;
+};
+
 /**
  * struct tipc_node - TIPC node structure
  * @addr: network address of node
@@ -132,6 +140,7 @@ struct tipc_node {
 	struct hlist_node hash;
 	int active_links[2];
 	struct tipc_link_entry links[MAX_BEARERS];
+	struct tipc_bclink_entry bc_entry;
 	int action_flags;
 	struct tipc_node_bclink bclink;
 	struct list_head list;