tipc: add functionality to lookup multicast destination nodes

As a further preparation for the upcoming 'replicast' functionality,
we add some necessary structs and functions for looking up and returning
a list of all nodes that host destinations for a given multicast message.

Reviewed-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/bcast.c

@@ -39,9 +39,8 @@
 #include "socket.h"
 #include "msg.h"
 #include "bcast.h"
-#include "name_distr.h"
 #include "link.h"
-#include "node.h"
+#include "name_table.h"
 
 #define	BCLINK_WIN_DEFAULT	50	/* bcast link window size (default) */
 #define	BCLINK_WIN_MIN	        32	/* bcast minimum link window size */
@@ -434,3 +433,33 @@ void tipc_bcast_stop(struct net *net)
 	kfree(tn->bcbase);
 	kfree(tn->bcl);
 }
+
+void tipc_nlist_init(struct tipc_nlist *nl, u32 self)
+{
+	memset(nl, 0, sizeof(*nl));
+	INIT_LIST_HEAD(&nl->list);
+	nl->self = self;
+}
+
+void tipc_nlist_add(struct tipc_nlist *nl, u32 node)
+{
+	if (node == nl->self)
+		nl->local = true;
+	else if (u32_push(&nl->list, node))
+		nl->remote++;
+}
+
+void tipc_nlist_del(struct tipc_nlist *nl, u32 node)
+{
+	if (node == nl->self)
+		nl->local = false;
+	else if (u32_del(&nl->list, node))
+		nl->remote--;
+}
+
+void tipc_nlist_purge(struct tipc_nlist *nl)
+{
+	u32_list_purge(&nl->list);
+	nl->remote = 0;
+	nl->local = 0;
+}

net/tipc/bcast.h

@@ -42,9 +42,22 @@
 struct tipc_node;
 struct tipc_msg;
 struct tipc_nl_msg;
-struct tipc_node_map;
+struct tipc_nlist;
+struct tipc_nitem;
 extern const char tipc_bclink_name[];
 
+struct tipc_nlist {
+	struct list_head list;
+	u32 self;
+	u16 remote;
+	bool local;
+};
+
+void tipc_nlist_init(struct tipc_nlist *nl, u32 self);
+void tipc_nlist_purge(struct tipc_nlist *nl);
+void tipc_nlist_add(struct tipc_nlist *nl, u32 node);
+void tipc_nlist_del(struct tipc_nlist *nl, u32 node);
+
 int tipc_bcast_init(struct net *net);
 void tipc_bcast_stop(struct net *net);
 void tipc_bcast_add_peer(struct net *net, struct tipc_link *l,

net/tipc/name_table.c

@@ -645,6 +645,39 @@ exit:
 	return res;
 }
 
+/* tipc_nametbl_lookup_dst_nodes - find broadcast destination nodes
+ * - Creates list of nodes that overlap the given multicast address
+ * - Determines if any node local ports overlap
+ */
+void tipc_nametbl_lookup_dst_nodes(struct net *net, u32 type, u32 lower,
+				   u32 upper, u32 domain,
+				   struct tipc_nlist *nodes)
+{
+	struct sub_seq *sseq, *stop;
+	struct publication *publ;
+	struct name_info *info;
+	struct name_seq *seq;
+
+	rcu_read_lock();
+	seq = nametbl_find_seq(net, type);
+	if (!seq)
+		goto exit;
+
+	spin_lock_bh(&seq->lock);
+	sseq = seq->sseqs + nameseq_locate_subseq(seq, lower);
+	stop = seq->sseqs + seq->first_free;
+	for (; sseq->lower <= upper && sseq != stop; sseq++) {
+		info = sseq->info;
+		list_for_each_entry(publ, &info->zone_list, zone_list) {
+			if (tipc_in_scope(domain, publ->node))
+				tipc_nlist_add(nodes, publ->node);
+		}
+	}
+	spin_unlock_bh(&seq->lock);
+exit:
+	rcu_read_unlock();
+}
+
 /*
  * tipc_nametbl_publish - add name publication to network name tables
  */
@@ -1022,11 +1055,6 @@ int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
-struct u32_item {
-	struct list_head list;
-	u32 value;
-};
-
 bool u32_find(struct list_head *l, u32 value)
 {
 	struct u32_item *item;

net/tipc/name_table.h

@@ -39,6 +39,7 @@
 
 struct tipc_subscription;
 struct tipc_plist;
+struct tipc_nlist;
 
 /*
  * TIPC name types reserved for internal TIPC use (both current and planned)
@@ -100,6 +101,9 @@ int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb);
 u32 tipc_nametbl_translate(struct net *net, u32 type, u32 instance, u32 *node);
 int tipc_nametbl_mc_translate(struct net *net, u32 type, u32 lower, u32 upper,
 			      u32 limit, struct list_head *dports);
+void tipc_nametbl_lookup_dst_nodes(struct net *net, u32 type, u32 lower,
+				   u32 upper, u32 domain,
+				   struct tipc_nlist *nodes);
 struct publication *tipc_nametbl_publish(struct net *net, u32 type, u32 lower,
 					 u32 upper, u32 scope, u32 port_ref,
 					 u32 key);
@@ -116,6 +120,11 @@ void tipc_nametbl_unsubscribe(struct tipc_subscription *s);
 int tipc_nametbl_init(struct net *net);
 void tipc_nametbl_stop(struct net *net);
 
+struct u32_item {
+	struct list_head list;
+	u32 value;
+};
+
 bool u32_push(struct list_head *l, u32 value);
 u32 u32_pop(struct list_head *l);
 bool u32_find(struct list_head *l, u32 value);