diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 55aeba681cf4..656ebc79c64e 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -305,17 +305,17 @@ static int tipc_rcast_xmit(struct net *net, struct sk_buff_head *pkts,
  * @skb: socket buffer to copy
  * @method: send method to be used
  * @dests: destination nodes for message.
- * @cong_link_cnt: returns number of encountered congested destination links
  * Returns 0 if success, otherwise errno
  */
 static int tipc_mcast_send_sync(struct net *net, struct sk_buff *skb,
 				struct tipc_mc_method *method,
-				struct tipc_nlist *dests,
-				u16 *cong_link_cnt)
+				struct tipc_nlist *dests)
 {
 	struct tipc_msg *hdr, *_hdr;
 	struct sk_buff_head tmpq;
 	struct sk_buff *_skb;
+	u16 cong_link_cnt;
+	int rc = 0;
 
 	/* Is a cluster supporting with new capabilities ? */
 	if (!(tipc_net(net)->capabilities & TIPC_MCAST_RBCTL))
@@ -343,18 +343,19 @@ static int tipc_mcast_send_sync(struct net *net, struct sk_buff *skb,
 	_hdr = buf_msg(_skb);
 	msg_set_size(_hdr, MCAST_H_SIZE);
 	msg_set_is_rcast(_hdr, !msg_is_rcast(hdr));
+	msg_set_errcode(_hdr, TIPC_ERR_NO_PORT);
 
 	__skb_queue_head_init(&tmpq);
 	__skb_queue_tail(&tmpq, _skb);
 	if (method->rcast)
-		tipc_bcast_xmit(net, &tmpq, cong_link_cnt);
+		rc = tipc_bcast_xmit(net, &tmpq, &cong_link_cnt);
 	else
-		tipc_rcast_xmit(net, &tmpq, dests, cong_link_cnt);
+		rc = tipc_rcast_xmit(net, &tmpq, dests, &cong_link_cnt);
 
 	/* This queue should normally be empty by now */
 	__skb_queue_purge(&tmpq);
 
-	return 0;
+	return rc;
 }
 
 /* tipc_mcast_xmit - deliver message to indicated destination nodes
@@ -396,9 +397,14 @@ int tipc_mcast_xmit(struct net *net, struct sk_buff_head *pkts,
 		msg_set_is_rcast(hdr, method->rcast);
 
 		/* Switch method ? */
-		if (rcast != method->rcast)
-			tipc_mcast_send_sync(net, skb, method,
-					     dests, cong_link_cnt);
+		if (rcast != method->rcast) {
+			rc = tipc_mcast_send_sync(net, skb, method, dests);
+			if (unlikely(rc)) {
+				pr_err("Unable to send SYN: method %d, rc %d\n",
+				       rcast, rc);
+				goto exit;
+			}
+		}
 
 		if (method->rcast)
 			rc = tipc_rcast_xmit(net, pkts, dests, cong_link_cnt);
diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index b043e8c6397a..bfe43da127c0 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -194,6 +194,7 @@ void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
 {
 	struct tipc_net *tn = tipc_net(net);
 	struct tipc_msg *hdr = buf_msg(skb);
+	u32 pnet_hash = msg_peer_net_hash(hdr);
 	u16 caps = msg_node_capabilities(hdr);
 	bool legacy = tn->legacy_addr_format;
 	u32 sugg = msg_sugg_node_addr(hdr);
@@ -242,9 +243,8 @@ void tipc_disc_rcv(struct net *net, struct sk_buff *skb,
 		return;
 	if (!tipc_in_scope(legacy, b->domain, src))
 		return;
-	tipc_node_check_dest(net, src, peer_id, b, caps, signature,
-			     msg_peer_net_hash(hdr), &maddr, &respond,
-			     &dupl_addr);
+	tipc_node_check_dest(net, src, peer_id, b, caps, signature, pnet_hash,
+			     &maddr, &respond, &dupl_addr);
 	if (dupl_addr)
 		disc_dupl_alert(b, src, &maddr);
 	if (!respond)
diff --git a/net/tipc/name_table.c b/net/tipc/name_table.c
index 92d04dc2a44b..359b2bc888cf 100644
--- a/net/tipc/name_table.c
+++ b/net/tipc/name_table.c
@@ -36,6 +36,7 @@
 
 #include <net/sock.h>
 #include <linux/list_sort.h>
+#include <linux/rbtree_augmented.h>
 #include "core.h"
 #include "netlink.h"
 #include "name_table.h"
@@ -51,6 +52,7 @@
  * @lower: service range lower bound
  * @upper: service range upper bound
  * @tree_node: member of service range RB tree
+ * @max: largest 'upper' in this node subtree
  * @local_publ: list of identical publications made from this node
  *   Used by closest_first lookup and multicast lookup algorithm
  * @all_publ: all publications identical to this one, whatever node and scope
@@ -60,6 +62,7 @@ struct service_range {
 	u32 lower;
 	u32 upper;
 	struct rb_node tree_node;
+	u32 max;
 	struct list_head local_publ;
 	struct list_head all_publ;
 };
@@ -84,6 +87,130 @@ struct tipc_service {
 	struct rcu_head rcu;
 };
 
+#define service_range_upper(sr) ((sr)->upper)
+RB_DECLARE_CALLBACKS_MAX(static, sr_callbacks,
+			 struct service_range, tree_node, u32, max,
+			 service_range_upper)
+
+#define service_range_entry(rbtree_node)				\
+	(container_of(rbtree_node, struct service_range, tree_node))
+
+#define service_range_overlap(sr, start, end)				\
+	((sr)->lower <= (end) && (sr)->upper >= (start))
+
+/**
+ * service_range_foreach_match - iterate over tipc service rbtree for each
+ *                               range match
+ * @sr: the service range pointer as a loop cursor
+ * @sc: the pointer to tipc service which holds the service range rbtree
+ * @start, end: the range (end >= start) for matching
+ */
+#define service_range_foreach_match(sr, sc, start, end)			\
+	for (sr = service_range_match_first((sc)->ranges.rb_node,	\
+					    start,			\
+					    end);			\
+	     sr;							\
+	     sr = service_range_match_next(&(sr)->tree_node,		\
+					   start,			\
+					   end))
+
+/**
+ * service_range_match_first - find first service range matching a range
+ * @n: the root node of service range rbtree for searching
+ * @start, end: the range (end >= start) for matching
+ *
+ * Return: the leftmost service range node in the rbtree that overlaps the
+ * specific range if any. Otherwise, returns NULL.
+ */
+static struct service_range *service_range_match_first(struct rb_node *n,
+						       u32 start, u32 end)
+{
+	struct service_range *sr;
+	struct rb_node *l, *r;
+
+	/* Non overlaps in tree at all? */
+	if (!n || service_range_entry(n)->max < start)
+		return NULL;
+
+	while (n) {
+		l = n->rb_left;
+		if (l && service_range_entry(l)->max >= start) {
+			/* A leftmost overlap range node must be one in the left
+			 * subtree. If not, it has lower > end, then nodes on
+			 * the right side cannot satisfy the condition either.
+			 */
+			n = l;
+			continue;
+		}
+
+		/* No one in the left subtree can match, return if this node is
+		 * an overlap i.e. leftmost.
+		 */
+		sr = service_range_entry(n);
+		if (service_range_overlap(sr, start, end))
+			return sr;
+
+		/* Ok, try to lookup on the right side */
+		r = n->rb_right;
+		if (sr->lower <= end &&
+		    r && service_range_entry(r)->max >= start) {
+			n = r;
+			continue;
+		}
+		break;
+	}
+
+	return NULL;
+}
+
+/**
+ * service_range_match_next - find next service range matching a range
+ * @n: a node in service range rbtree from which the searching starts
+ * @start, end: the range (end >= start) for matching
+ *
+ * Return: the next service range node to the given node in the rbtree that
+ * overlaps the specific range if any. Otherwise, returns NULL.
+ */
+static struct service_range *service_range_match_next(struct rb_node *n,
+						      u32 start, u32 end)
+{
+	struct service_range *sr;
+	struct rb_node *p, *r;
+
+	while (n) {
+		r = n->rb_right;
+		if (r && service_range_entry(r)->max >= start)
+			/* A next overlap range node must be one in the right
+			 * subtree. If not, it has lower > end, then any next
+			 * successor (- an ancestor) of this node cannot
+			 * satisfy the condition either.
+			 */
+			return service_range_match_first(r, start, end);
+
+		/* No one in the right subtree can match, go up to find an
+		 * ancestor of this node which is parent of a left-hand child.
+		 */
+		while ((p = rb_parent(n)) && n == p->rb_right)
+			n = p;
+		if (!p)
+			break;
+
+		/* Return if this ancestor is an overlap */
+		sr = service_range_entry(p);
+		if (service_range_overlap(sr, start, end))
+			return sr;
+
+		/* Ok, try to lookup more from this ancestor */
+		if (sr->lower <= end) {
+			n = p;
+			continue;
+		}
+		break;
+	}
+
+	return NULL;
+}
+
 static int hash(int x)
 {
 	return x & (TIPC_NAMETBL_SIZE - 1);
@@ -139,84 +266,51 @@ static struct tipc_service *tipc_service_create(u32 type, struct hlist_head *hd)
 	return service;
 }
 
-/**
- * tipc_service_first_range - find first service range in tree matching instance
- *
- * Very time-critical, so binary search through range rb tree
- */
-static struct service_range *tipc_service_first_range(struct tipc_service *sc,
-						      u32 instance)
-{
-	struct rb_node *n = sc->ranges.rb_node;
-	struct service_range *sr;
-
-	while (n) {
-		sr = container_of(n, struct service_range, tree_node);
-		if (sr->lower > instance)
-			n = n->rb_left;
-		else if (sr->upper < instance)
-			n = n->rb_right;
-		else
-			return sr;
-	}
-	return NULL;
-}
-
 /*  tipc_service_find_range - find service range matching publication parameters
  */
 static struct service_range *tipc_service_find_range(struct tipc_service *sc,
 						     u32 lower, u32 upper)
 {
-	struct rb_node *n = sc->ranges.rb_node;
 	struct service_range *sr;
 
-	sr = tipc_service_first_range(sc, lower);
-	if (!sr)
-		return NULL;
-
-	/* Look for exact match */
-	for (n = &sr->tree_node; n; n = rb_next(n)) {
-		sr = container_of(n, struct service_range, tree_node);
-		if (sr->upper == upper)
-			break;
+	service_range_foreach_match(sr, sc, lower, upper) {
+		/* Look for exact match */
+		if (sr->lower == lower && sr->upper == upper)
+			return sr;
 	}
-	if (!n || sr->lower != lower || sr->upper != upper)
-		return NULL;
 
-	return sr;
+	return NULL;
 }
 
 static struct service_range *tipc_service_create_range(struct tipc_service *sc,
 						       u32 lower, u32 upper)
 {
 	struct rb_node **n, *parent = NULL;
-	struct service_range *sr, *tmp;
+	struct service_range *sr;
 
 	n = &sc->ranges.rb_node;
 	while (*n) {
-		tmp = container_of(*n, struct service_range, tree_node);
 		parent = *n;
-		tmp = container_of(parent, struct service_range, tree_node);
-		if (lower < tmp->lower)
-			n = &(*n)->rb_left;
-		else if (lower > tmp->lower)
-			n = &(*n)->rb_right;
-		else if (upper < tmp->upper)
-			n = &(*n)->rb_left;
-		else if (upper > tmp->upper)
-			n = &(*n)->rb_right;
+		sr = service_range_entry(parent);
+		if (lower == sr->lower && upper == sr->upper)
+			return sr;
+		if (sr->max < upper)
+			sr->max = upper;
+		if (lower <= sr->lower)
+			n = &parent->rb_left;
 		else
-			return tmp;
+			n = &parent->rb_right;
 	}
 	sr = kzalloc(sizeof(*sr), GFP_ATOMIC);
 	if (!sr)
 		return NULL;
 	sr->lower = lower;
 	sr->upper = upper;
+	sr->max = upper;
 	INIT_LIST_HEAD(&sr->local_publ);
 	INIT_LIST_HEAD(&sr->all_publ);
 	rb_link_node(&sr->tree_node, parent, n);
-	rb_insert_color(&sr->tree_node, &sc->ranges);
+	rb_insert_augmented(&sr->tree_node, &sc->ranges, &sr_callbacks);
 	return sr;
 }
 
@@ -310,7 +404,6 @@ static void tipc_service_subscribe(struct tipc_service *service,
 	struct list_head publ_list;
 	struct service_range *sr;
 	struct tipc_name_seq ns;
-	struct rb_node *n;
 	u32 filter;
 
 	ns.type = tipc_sub_read(sb, seq.type);
@@ -325,13 +418,7 @@ static void tipc_service_subscribe(struct tipc_service *service,
 		return;
 
 	INIT_LIST_HEAD(&publ_list);
-	for (n = rb_first(&service->ranges); n; n = rb_next(n)) {
-		sr = container_of(n, struct service_range, tree_node);
-		if (sr->lower > ns.upper)
-			break;
-		if (!tipc_sub_check_overlap(&ns, sr->lower, sr->upper))
-			continue;
-
+	service_range_foreach_match(sr, service, ns.lower, ns.upper) {
 		first = NULL;
 		list_for_each_entry(p, &sr->all_publ, all_publ) {
 			if (filter & TIPC_SUB_PORTS)
@@ -425,7 +512,7 @@ struct publication *tipc_nametbl_remove_publ(struct net *net, u32 type,
 
 	/* Remove service range item if this was its last publication */
 	if (list_empty(&sr->all_publ)) {
-		rb_erase(&sr->tree_node, &sc->ranges);
+		rb_erase_augmented(&sr->tree_node, &sc->ranges, &sr_callbacks);
 		kfree(sr);
 	}
 
@@ -473,34 +560,39 @@ u32 tipc_nametbl_translate(struct net *net, u32 type, u32 instance, u32 *dnode)
 	rcu_read_lock();
 	sc = tipc_service_find(net, type);
 	if (unlikely(!sc))
-		goto not_found;
+		goto exit;
 
 	spin_lock_bh(&sc->lock);
-	sr = tipc_service_first_range(sc, instance);
-	if (unlikely(!sr))
-		goto no_match;
-
-	/* Select lookup algorithm: local, closest-first or round-robin */
-	if (*dnode == self) {
-		list = &sr->local_publ;
-		if (list_empty(list))
-			goto no_match;
-		p = list_first_entry(list, struct publication, local_publ);
-		list_move_tail(&p->local_publ, &sr->local_publ);
-	} else if (legacy && !*dnode && !list_empty(&sr->local_publ)) {
-		list = &sr->local_publ;
-		p = list_first_entry(list, struct publication, local_publ);
-		list_move_tail(&p->local_publ, &sr->local_publ);
-	} else {
-		list = &sr->all_publ;
-		p = list_first_entry(list, struct publication, all_publ);
-		list_move_tail(&p->all_publ, &sr->all_publ);
+	service_range_foreach_match(sr, sc, instance, instance) {
+		/* Select lookup algo: local, closest-first or round-robin */
+		if (*dnode == self) {
+			list = &sr->local_publ;
+			if (list_empty(list))
+				continue;
+			p = list_first_entry(list, struct publication,
+					     local_publ);
+			list_move_tail(&p->local_publ, &sr->local_publ);
+		} else if (legacy && !*dnode && !list_empty(&sr->local_publ)) {
+			list = &sr->local_publ;
+			p = list_first_entry(list, struct publication,
+					     local_publ);
+			list_move_tail(&p->local_publ, &sr->local_publ);
+		} else {
+			list = &sr->all_publ;
+			p = list_first_entry(list, struct publication,
+					     all_publ);
+			list_move_tail(&p->all_publ, &sr->all_publ);
+		}
+		port = p->port;
+		node = p->node;
+		/* Todo: as for legacy, pick the first matching range only, a
+		 * "true" round-robin will be performed as needed.
+		 */
+		break;
 	}
-	port = p->port;
-	node = p->node;
-no_match:
 	spin_unlock_bh(&sc->lock);
-not_found:
+
+exit:
 	rcu_read_unlock();
 	*dnode = node;
 	return port;
@@ -523,7 +615,8 @@ bool tipc_nametbl_lookup(struct net *net, u32 type, u32 instance, u32 scope,
 
 	spin_lock_bh(&sc->lock);
 
-	sr = tipc_service_first_range(sc, instance);
+	/* Todo: a full search i.e. service_range_foreach_match() instead? */
+	sr = service_range_match_first(sc->ranges.rb_node, instance, instance);
 	if (!sr)
 		goto no_match;
 
@@ -552,7 +645,6 @@ void tipc_nametbl_mc_lookup(struct net *net, u32 type, u32 lower, u32 upper,
 	struct service_range *sr;
 	struct tipc_service *sc;
 	struct publication *p;
-	struct rb_node *n;
 
 	rcu_read_lock();
 	sc = tipc_service_find(net, type);
@@ -560,13 +652,7 @@ void tipc_nametbl_mc_lookup(struct net *net, u32 type, u32 lower, u32 upper,
 		goto exit;
 
 	spin_lock_bh(&sc->lock);
-
-	for (n = rb_first(&sc->ranges); n; n = rb_next(n)) {
-		sr = container_of(n, struct service_range, tree_node);
-		if (sr->upper < lower)
-			continue;
-		if (sr->lower > upper)
-			break;
+	service_range_foreach_match(sr, sc, lower, upper) {
 		list_for_each_entry(p, &sr->local_publ, local_publ) {
 			if (p->scope == scope || (!exact && p->scope < scope))
 				tipc_dest_push(dports, 0, p->port);
@@ -587,7 +673,6 @@ void tipc_nametbl_lookup_dst_nodes(struct net *net, u32 type, u32 lower,
 	struct service_range *sr;
 	struct tipc_service *sc;
 	struct publication *p;
-	struct rb_node *n;
 
 	rcu_read_lock();
 	sc = tipc_service_find(net, type);
@@ -595,13 +680,7 @@ void tipc_nametbl_lookup_dst_nodes(struct net *net, u32 type, u32 lower,
 		goto exit;
 
 	spin_lock_bh(&sc->lock);
-
-	for (n = rb_first(&sc->ranges); n; n = rb_next(n)) {
-		sr = container_of(n, struct service_range, tree_node);
-		if (sr->upper < lower)
-			continue;
-		if (sr->lower > upper)
-			break;
+	service_range_foreach_match(sr, sc, lower, upper) {
 		list_for_each_entry(p, &sr->all_publ, all_publ) {
 			tipc_nlist_add(nodes, p->node);
 		}
@@ -799,7 +878,7 @@ static void tipc_service_delete(struct net *net, struct tipc_service *sc)
 			tipc_service_remove_publ(sr, p->node, p->key);
 			kfree_rcu(p, rcu);
 		}
-		rb_erase(&sr->tree_node, &sc->ranges);
+		rb_erase_augmented(&sr->tree_node, &sc->ranges, &sr_callbacks);
 		kfree(sr);
 	}
 	hlist_del_init_rcu(&sc->service_list);
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 41688da233ab..6552f986774c 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1364,8 +1364,8 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
 	struct tipc_msg *hdr = &tsk->phdr;
 	struct tipc_name_seq *seq;
 	struct sk_buff_head pkts;
-	u32 dport, dnode = 0;
-	u32 type, inst;
+	u32 dport = 0, dnode = 0;
+	u32 type = 0, inst = 0;
 	int mtu, rc;
 
 	if (unlikely(dlen > TIPC_MAX_USER_MSG_SIZE))
@@ -1418,23 +1418,11 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
 		type = dest->addr.name.name.type;
 		inst = dest->addr.name.name.instance;
 		dnode = dest->addr.name.domain;
-		msg_set_type(hdr, TIPC_NAMED_MSG);
-		msg_set_hdr_sz(hdr, NAMED_H_SIZE);
-		msg_set_nametype(hdr, type);
-		msg_set_nameinst(hdr, inst);
-		msg_set_lookup_scope(hdr, tipc_node2scope(dnode));
 		dport = tipc_nametbl_translate(net, type, inst, &dnode);
-		msg_set_destnode(hdr, dnode);
-		msg_set_destport(hdr, dport);
 		if (unlikely(!dport && !dnode))
 			return -EHOSTUNREACH;
 	} else if (dest->addrtype == TIPC_ADDR_ID) {
 		dnode = dest->addr.id.node;
-		msg_set_type(hdr, TIPC_DIRECT_MSG);
-		msg_set_lookup_scope(hdr, 0);
-		msg_set_destnode(hdr, dnode);
-		msg_set_destport(hdr, dest->addr.id.ref);
-		msg_set_hdr_sz(hdr, BASIC_H_SIZE);
 	} else {
 		return -EINVAL;
 	}
@@ -1445,6 +1433,22 @@ static int __tipc_sendmsg(struct socket *sock, struct msghdr *m, size_t dlen)
 	if (unlikely(rc))
 		return rc;
 
+	if (dest->addrtype == TIPC_ADDR_NAME) {
+		msg_set_type(hdr, TIPC_NAMED_MSG);
+		msg_set_hdr_sz(hdr, NAMED_H_SIZE);
+		msg_set_nametype(hdr, type);
+		msg_set_nameinst(hdr, inst);
+		msg_set_lookup_scope(hdr, tipc_node2scope(dnode));
+		msg_set_destnode(hdr, dnode);
+		msg_set_destport(hdr, dport);
+	} else { /* TIPC_ADDR_ID */
+		msg_set_type(hdr, TIPC_DIRECT_MSG);
+		msg_set_lookup_scope(hdr, 0);
+		msg_set_destnode(hdr, dnode);
+		msg_set_destport(hdr, dest->addr.id.ref);
+		msg_set_hdr_sz(hdr, BASIC_H_SIZE);
+	}
+
 	__skb_queue_head_init(&pkts);
 	mtu = tipc_node_get_mtu(net, dnode, tsk->portid, false);
 	rc = tipc_msg_build(hdr, m, 0, dlen, mtu, &pkts);