7 files changed, 39 insertions, 6 deletions

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 74ee09a..d8c399d 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -148,9 +148,9 @@ void tipc_bclink_input(struct net *net)
 	tipc_sk_mcast_rcv(net, &tn->bcbase->arrvq, &tn->bcbase->inputq);
 }
 
-uint  tipc_bcast_get_mtu(void)
+int tipc_bcast_get_mtu(struct net *net)
 {
-	return MAX_PKT_DEFAULT_MCAST;
+	return tipc_link_mtu(tipc_bc_sndlink(net));
 }
 
 static u16 bcbuf_acks(struct sk_buff *skb)
@@ -175,7 +175,7 @@ static void tipc_bcbase_select_primary(struct net *net)
 {
 	struct tipc_bc_base *bb = tipc_bc_base(net);
 	int all_dests =  tipc_link_bc_peers(bb->link);
-	int i;
+	int i, mtu;
 
 	bb->primary_bearer = INVALID_BEARER_ID;
 
@@ -183,6 +183,13 @@ static void tipc_bcbase_select_primary(struct net *net)
 		return;
 
 	for (i = 0; i < MAX_BEARERS; i++) {
+		if (!bb->dests[i])
+			continue;
+
+		mtu = tipc_bearer_mtu(net, i);
+		if (mtu < tipc_link_mtu(bb->link))
+			tipc_link_set_mtu(bb->link, mtu);
+
 		if (bb->dests[i] < all_dests)
 			continue;
 
@@ -1220,7 +1227,7 @@ int tipc_bcast_init(struct net *net)
 	bb->node.net = net;
 
 	if (!tipc_link_bc_create(&bb->node, 0, 0,
-				 MAX_PKT_DEFAULT_MCAST,
+				 U16_MAX,
 				 BCLINK_WIN_DEFAULT,
 				 0,
 				 &bb->inputq,
diff --git a/net/tipc/bcast.h b/net/tipc/bcast.h
index 76b747a..0cc7220 100644
--- a/net/tipc/bcast.h
+++ b/net/tipc/bcast.h
@@ -63,7 +63,7 @@ void tipc_bcbearer_sort(struct net *net, struct tipc_node_map *nm_ptr,
 			u32 node, bool action);
 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_get_mtu(struct net *net);
 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);
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 62f47ec..b39f631 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -464,6 +464,19 @@ void tipc_bearer_send(struct net *net, u32 bearer_id, struct sk_buff *buf,
 	rcu_read_unlock();
 }
 
+int tipc_bearer_mtu(struct net *net, u32 bearer_id)
+{
+	int mtu = 0;
+	struct tipc_bearer *b;
+
+	rcu_read_lock();
+	b = rcu_dereference_rtnl(tipc_net(net)->bearer_list[bearer_id]);
+	if (b)
+		mtu = b->mtu;
+	rcu_read_unlock();
+	return mtu;
+}
+
 /* tipc_bearer_xmit() -send buffer to destination over bearer
  */
 void tipc_bearer_xmit(struct net *net, u32 bearer_id,
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 9fc1e07..2ba8a7e 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -218,6 +218,7 @@ void tipc_bearer_cleanup(void);
 void tipc_bearer_stop(struct net *net);
 void tipc_bearer_send(struct net *net, u32 bearer_id, struct sk_buff *buf,
 		      struct tipc_media_addr *dest);
+int tipc_bearer_mtu(struct net *net, u32 bearer_id);
 void tipc_bearer_xmit(struct net *net, u32 bearer_id,
 		      struct sk_buff_head *xmitq,
 		      struct tipc_media_addr *dst);
diff --git a/net/tipc/link.c b/net/tipc/link.c
index ff725c3..3b98f8e 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -212,6 +212,16 @@ int tipc_link_bc_peers(struct tipc_link *l)
 	return l->ackers;
 }
 
+void tipc_link_set_mtu(struct tipc_link *l, int mtu)
+{
+	l->mtu = mtu;
+}
+
+int tipc_link_mtu(struct tipc_link *l)
+{
+	return l->mtu;
+}
+
 static u32 link_own_addr(struct tipc_link *l)
 {
 	return msg_prevnode(l->pmsg);
diff --git a/net/tipc/link.h b/net/tipc/link.h
index 28a6396..9b5198e9 100644
--- a/net/tipc/link.h
+++ b/net/tipc/link.h
@@ -281,6 +281,8 @@ 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_set_mtu(struct tipc_link *l, int mtu);
+int tipc_link_mtu(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,
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index e2e35b7..552dbab 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -689,7 +689,7 @@ static int tipc_sendmcast(struct  socket *sock, struct tipc_name_seq *seq,
 	msg_set_hdr_sz(mhdr, MCAST_H_SIZE);
 
 new_mtu:
-	mtu = tipc_bcast_get_mtu();
+	mtu = tipc_bcast_get_mtu(net);
 	rc = tipc_msg_build(mhdr, msg, 0, dsz, mtu, pktchain);
 	if (unlikely(rc < 0))
 		return rc;