Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / net / tipc / bcast.c
diff --git a/kernel/net/tipc/bcast.c b/kernel/net/tipc/bcast.c
new file mode 100644 (file)
index 0000000..c5cbdcb
--- /dev/null
@@ -0,0 +1,986 @@
+/*
+ * net/tipc/bcast.c: TIPC broadcast code
+ *
+ * Copyright (c) 2004-2006, 2014-2015, Ericsson AB
+ * Copyright (c) 2004, Intel Corporation.
+ * Copyright (c) 2005, 2010-2011, Wind River Systems
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "socket.h"
+#include "msg.h"
+#include "bcast.h"
+#include "name_distr.h"
+#include "core.h"
+
+#define        MAX_PKT_DEFAULT_MCAST   1500    /* bcast link max packet size (fixed) */
+#define        BCLINK_WIN_DEFAULT      20      /* bcast link window size (default) */
+
+const char tipc_bclink_name[] = "broadcast-link";
+
+static void tipc_nmap_diff(struct tipc_node_map *nm_a,
+                          struct tipc_node_map *nm_b,
+                          struct tipc_node_map *nm_diff);
+static void tipc_nmap_add(struct tipc_node_map *nm_ptr, u32 node);
+static void tipc_nmap_remove(struct tipc_node_map *nm_ptr, u32 node);
+
+static void tipc_bclink_lock(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       spin_lock_bh(&tn->bclink->lock);
+}
+
+static void tipc_bclink_unlock(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       spin_unlock_bh(&tn->bclink->lock);
+}
+
+void tipc_bclink_input(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       tipc_sk_mcast_rcv(net, &tn->bclink->arrvq, &tn->bclink->inputq);
+}
+
+uint  tipc_bclink_get_mtu(void)
+{
+       return MAX_PKT_DEFAULT_MCAST;
+}
+
+static u32 bcbuf_acks(struct sk_buff *buf)
+{
+       return (u32)(unsigned long)TIPC_SKB_CB(buf)->handle;
+}
+
+static void bcbuf_set_acks(struct sk_buff *buf, u32 acks)
+{
+       TIPC_SKB_CB(buf)->handle = (void *)(unsigned long)acks;
+}
+
+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);
+
+       tipc_bclink_lock(net);
+       tipc_nmap_add(&tn->bclink->bcast_nodes, addr);
+       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->bclink->bcast_nodes, addr);
+       tipc_bclink_unlock(net);
+}
+
+static void bclink_set_last_sent(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_link *bcl = tn->bcl;
+       struct sk_buff *skb = skb_peek(&bcl->backlogq);
+
+       if (skb)
+               bcl->fsm_msg_cnt = mod(buf_seqno(skb) - 1);
+       else
+               bcl->fsm_msg_cnt = mod(bcl->next_out_no - 1);
+}
+
+u32 tipc_bclink_get_last_sent(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       return tn->bcl->fsm_msg_cnt;
+}
+
+static void bclink_update_last_sent(struct tipc_node *node, u32 seqno)
+{
+       node->bclink.last_sent = less_eq(node->bclink.last_sent, seqno) ?
+                                               seqno : node->bclink.last_sent;
+}
+
+/**
+ * tipc_bclink_retransmit_to - get most recent node to request retransmission
+ *
+ * Called with bclink_lock locked
+ */
+struct tipc_node *tipc_bclink_retransmit_to(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       return tn->bclink->retransmit_to;
+}
+
+/**
+ * bclink_retransmit_pkt - retransmit broadcast packets
+ * @after: sequence number of last packet to *not* retransmit
+ * @to: sequence number of last packet to retransmit
+ *
+ * Called with bclink_lock locked
+ */
+static void bclink_retransmit_pkt(struct tipc_net *tn, u32 after, u32 to)
+{
+       struct sk_buff *skb;
+       struct tipc_link *bcl = tn->bcl;
+
+       skb_queue_walk(&bcl->transmq, skb) {
+               if (more(buf_seqno(skb), after)) {
+                       tipc_link_retransmit(bcl, skb, mod(to - after));
+                       break;
+               }
+       }
+}
+
+/**
+ * tipc_bclink_wakeup_users - wake up pending users
+ *
+ * Called with no locks taken
+ */
+void tipc_bclink_wakeup_users(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       tipc_sk_rcv(net, &tn->bclink->link.wakeupq);
+}
+
+/**
+ * tipc_bclink_acknowledge - handle acknowledgement of broadcast packets
+ * @n_ptr: node that sent acknowledgement info
+ * @acked: broadcast sequence # that has been acknowledged
+ *
+ * Node is locked, bclink_lock unlocked.
+ */
+void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
+{
+       struct sk_buff *skb, *tmp;
+       unsigned int released = 0;
+       struct net *net = n_ptr->net;
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       if (unlikely(!n_ptr->bclink.recv_permitted))
+               return;
+
+       tipc_bclink_lock(net);
+
+       /* Bail out if tx queue is empty (no clean up is required) */
+       skb = skb_peek(&tn->bcl->transmq);
+       if (!skb)
+               goto exit;
+
+       /* Determine which messages need to be acknowledged */
+       if (acked == INVALID_LINK_SEQ) {
+               /*
+                * Contact with specified node has been lost, so need to
+                * acknowledge sent messages only (if other nodes still exist)
+                * or both sent and unsent messages (otherwise)
+                */
+               if (tn->bclink->bcast_nodes.count)
+                       acked = tn->bcl->fsm_msg_cnt;
+               else
+                       acked = tn->bcl->next_out_no;
+       } else {
+               /*
+                * Bail out if specified sequence number does not correspond
+                * to a message that has been sent and not yet acknowledged
+                */
+               if (less(acked, buf_seqno(skb)) ||
+                   less(tn->bcl->fsm_msg_cnt, acked) ||
+                   less_eq(acked, n_ptr->bclink.acked))
+                       goto exit;
+       }
+
+       /* Skip over packets that node has previously acknowledged */
+       skb_queue_walk(&tn->bcl->transmq, skb) {
+               if (more(buf_seqno(skb), n_ptr->bclink.acked))
+                       break;
+       }
+
+       /* Update packets that node is now acknowledging */
+       skb_queue_walk_from_safe(&tn->bcl->transmq, skb, tmp) {
+               if (more(buf_seqno(skb), acked))
+                       break;
+               bcbuf_decr_acks(skb);
+               bclink_set_last_sent(net);
+               if (bcbuf_acks(skb) == 0) {
+                       __skb_unlink(skb, &tn->bcl->transmq);
+                       kfree_skb(skb);
+                       released = 1;
+               }
+       }
+       n_ptr->bclink.acked = acked;
+
+       /* Try resolving broadcast link congestion, if necessary */
+       if (unlikely(skb_peek(&tn->bcl->backlogq))) {
+               tipc_link_push_packets(tn->bcl);
+               bclink_set_last_sent(net);
+       }
+       if (unlikely(released && !skb_queue_empty(&tn->bcl->wakeupq)))
+               n_ptr->action_flags |= TIPC_WAKEUP_BCAST_USERS;
+exit:
+       tipc_bclink_unlock(net);
+}
+
+/**
+ * tipc_bclink_update_link_state - update broadcast link state
+ *
+ * RCU and node lock set
+ */
+void tipc_bclink_update_link_state(struct tipc_node *n_ptr,
+                                  u32 last_sent)
+{
+       struct sk_buff *buf;
+       struct net *net = n_ptr->net;
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       /* Ignore "stale" link state info */
+       if (less_eq(last_sent, n_ptr->bclink.last_in))
+               return;
+
+       /* Update link synchronization state; quit if in sync */
+       bclink_update_last_sent(n_ptr, last_sent);
+
+       if (n_ptr->bclink.last_sent == n_ptr->bclink.last_in)
+               return;
+
+       /* Update out-of-sync state; quit if loss is still unconfirmed */
+       if ((++n_ptr->bclink.oos_state) == 1) {
+               if (n_ptr->bclink.deferred_size < (TIPC_MIN_LINK_WIN / 2))
+                       return;
+               n_ptr->bclink.oos_state++;
+       }
+
+       /* Don't NACK if one has been recently sent (or seen) */
+       if (n_ptr->bclink.oos_state & 0x1)
+               return;
+
+       /* Send NACK */
+       buf = tipc_buf_acquire(INT_H_SIZE);
+       if (buf) {
+               struct tipc_msg *msg = buf_msg(buf);
+               struct sk_buff *skb = skb_peek(&n_ptr->bclink.deferdq);
+               u32 to = skb ? buf_seqno(skb) - 1 : n_ptr->bclink.last_sent;
+
+               tipc_msg_init(tn->own_addr, msg, BCAST_PROTOCOL, STATE_MSG,
+                             INT_H_SIZE, n_ptr->addr);
+               msg_set_non_seq(msg, 1);
+               msg_set_mc_netid(msg, tn->net_id);
+               msg_set_bcast_ack(msg, n_ptr->bclink.last_in);
+               msg_set_bcgap_after(msg, n_ptr->bclink.last_in);
+               msg_set_bcgap_to(msg, to);
+
+               tipc_bclink_lock(net);
+               tipc_bearer_send(net, MAX_BEARERS, buf, NULL);
+               tn->bcl->stats.sent_nacks++;
+               tipc_bclink_unlock(net);
+               kfree_skb(buf);
+
+               n_ptr->bclink.oos_state++;
+       }
+}
+
+/**
+ * bclink_peek_nack - monitor retransmission requests sent by other nodes
+ *
+ * Delay any upcoming NACK by this node if another node has already
+ * requested the first message this node is going to ask for.
+ */
+static void bclink_peek_nack(struct net *net, struct tipc_msg *msg)
+{
+       struct tipc_node *n_ptr = tipc_node_find(net, msg_destnode(msg));
+
+       if (unlikely(!n_ptr))
+               return;
+
+       tipc_node_lock(n_ptr);
+       if (n_ptr->bclink.recv_permitted &&
+           (n_ptr->bclink.last_in != n_ptr->bclink.last_sent) &&
+           (n_ptr->bclink.last_in == msg_bcgap_after(msg)))
+               n_ptr->bclink.oos_state = 2;
+       tipc_node_unlock(n_ptr);
+       tipc_node_put(n_ptr);
+}
+
+/* tipc_bclink_xmit - deliver buffer chain to all nodes in cluster
+ *                    and to identified node local sockets
+ * @net: the applicable net namespace
+ * @list: chain of buffers containing message
+ * Consumes the buffer chain, except when returning -ELINKCONG
+ * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
+ */
+int tipc_bclink_xmit(struct net *net, struct sk_buff_head *list)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_link *bcl = tn->bcl;
+       struct tipc_bclink *bclink = tn->bclink;
+       int rc = 0;
+       int bc = 0;
+       struct sk_buff *skb;
+       struct sk_buff_head arrvq;
+       struct sk_buff_head inputq;
+
+       /* Prepare clone of message for local node */
+       skb = tipc_msg_reassemble(list);
+       if (unlikely(!skb)) {
+               __skb_queue_purge(list);
+               return -EHOSTUNREACH;
+       }
+       /* Broadcast to all nodes */
+       if (likely(bclink)) {
+               tipc_bclink_lock(net);
+               if (likely(bclink->bcast_nodes.count)) {
+                       rc = __tipc_link_xmit(net, bcl, list);
+                       if (likely(!rc)) {
+                               u32 len = skb_queue_len(&bcl->transmq);
+
+                               bclink_set_last_sent(net);
+                               bcl->stats.queue_sz_counts++;
+                               bcl->stats.accu_queue_sz += len;
+                       }
+                       bc = 1;
+               }
+               tipc_bclink_unlock(net);
+       }
+
+       if (unlikely(!bc))
+               __skb_queue_purge(list);
+
+       if (unlikely(rc)) {
+               kfree_skb(skb);
+               return rc;
+       }
+       /* Deliver message clone */
+       __skb_queue_head_init(&arrvq);
+       skb_queue_head_init(&inputq);
+       __skb_queue_tail(&arrvq, skb);
+       tipc_sk_mcast_rcv(net, &arrvq, &inputq);
+       return rc;
+}
+
+/**
+ * bclink_accept_pkt - accept an incoming, in-sequence broadcast packet
+ *
+ * Called with both sending node's lock and bclink_lock taken.
+ */
+static void bclink_accept_pkt(struct tipc_node *node, u32 seqno)
+{
+       struct tipc_net *tn = net_generic(node->net, tipc_net_id);
+
+       bclink_update_last_sent(node, seqno);
+       node->bclink.last_in = seqno;
+       node->bclink.oos_state = 0;
+       tn->bcl->stats.recv_info++;
+
+       /*
+        * Unicast an ACK periodically, ensuring that
+        * all nodes in the cluster don't ACK at the same time
+        */
+       if (((seqno - tn->own_addr) % TIPC_MIN_LINK_WIN) == 0) {
+               tipc_link_proto_xmit(node->active_links[node->addr & 1],
+                                    STATE_MSG, 0, 0, 0, 0);
+               tn->bcl->stats.sent_acks++;
+       }
+}
+
+/**
+ * tipc_bclink_rcv - receive a broadcast packet, and deliver upwards
+ *
+ * RCU is locked, no other locks set
+ */
+void tipc_bclink_rcv(struct net *net, struct sk_buff *buf)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_link *bcl = tn->bcl;
+       struct tipc_msg *msg = buf_msg(buf);
+       struct tipc_node *node;
+       u32 next_in;
+       u32 seqno;
+       int deferred = 0;
+       int pos = 0;
+       struct sk_buff *iskb;
+       struct sk_buff_head *arrvq, *inputq;
+
+       /* Screen out unwanted broadcast messages */
+       if (msg_mc_netid(msg) != tn->net_id)
+               goto exit;
+
+       node = tipc_node_find(net, msg_prevnode(msg));
+       if (unlikely(!node))
+               goto exit;
+
+       tipc_node_lock(node);
+       if (unlikely(!node->bclink.recv_permitted))
+               goto unlock;
+
+       /* Handle broadcast protocol message */
+       if (unlikely(msg_user(msg) == BCAST_PROTOCOL)) {
+               if (msg_type(msg) != STATE_MSG)
+                       goto unlock;
+               if (msg_destnode(msg) == tn->own_addr) {
+                       tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
+                       tipc_bclink_lock(net);
+                       bcl->stats.recv_nacks++;
+                       tn->bclink->retransmit_to = node;
+                       bclink_retransmit_pkt(tn, msg_bcgap_after(msg),
+                                             msg_bcgap_to(msg));
+                       tipc_bclink_unlock(net);
+                       tipc_node_unlock(node);
+               } else {
+                       tipc_node_unlock(node);
+                       bclink_peek_nack(net, msg);
+               }
+               tipc_node_put(node);
+               goto exit;
+       }
+
+       /* Handle in-sequence broadcast message */
+       seqno = msg_seqno(msg);
+       next_in = mod(node->bclink.last_in + 1);
+       arrvq = &tn->bclink->arrvq;
+       inputq = &tn->bclink->inputq;
+
+       if (likely(seqno == next_in)) {
+receive:
+               /* Deliver message to destination */
+               if (likely(msg_isdata(msg))) {
+                       tipc_bclink_lock(net);
+                       bclink_accept_pkt(node, seqno);
+                       spin_lock_bh(&inputq->lock);
+                       __skb_queue_tail(arrvq, buf);
+                       spin_unlock_bh(&inputq->lock);
+                       node->action_flags |= TIPC_BCAST_MSG_EVT;
+                       tipc_bclink_unlock(net);
+                       tipc_node_unlock(node);
+               } else if (msg_user(msg) == MSG_BUNDLER) {
+                       tipc_bclink_lock(net);
+                       bclink_accept_pkt(node, seqno);
+                       bcl->stats.recv_bundles++;
+                       bcl->stats.recv_bundled += msg_msgcnt(msg);
+                       pos = 0;
+                       while (tipc_msg_extract(buf, &iskb, &pos)) {
+                               spin_lock_bh(&inputq->lock);
+                               __skb_queue_tail(arrvq, iskb);
+                               spin_unlock_bh(&inputq->lock);
+                       }
+                       node->action_flags |= TIPC_BCAST_MSG_EVT;
+                       tipc_bclink_unlock(net);
+                       tipc_node_unlock(node);
+               } else if (msg_user(msg) == MSG_FRAGMENTER) {
+                       tipc_bclink_lock(net);
+                       bclink_accept_pkt(node, seqno);
+                       tipc_buf_append(&node->bclink.reasm_buf, &buf);
+                       if (unlikely(!buf && !node->bclink.reasm_buf)) {
+                               tipc_bclink_unlock(net);
+                               goto unlock;
+                       }
+                       bcl->stats.recv_fragments++;
+                       if (buf) {
+                               bcl->stats.recv_fragmented++;
+                               msg = buf_msg(buf);
+                               tipc_bclink_unlock(net);
+                               goto receive;
+                       }
+                       tipc_bclink_unlock(net);
+                       tipc_node_unlock(node);
+               } else {
+                       tipc_bclink_lock(net);
+                       bclink_accept_pkt(node, seqno);
+                       tipc_bclink_unlock(net);
+                       tipc_node_unlock(node);
+                       kfree_skb(buf);
+               }
+               buf = NULL;
+
+               /* Determine new synchronization state */
+               tipc_node_lock(node);
+               if (unlikely(!tipc_node_is_up(node)))
+                       goto unlock;
+
+               if (node->bclink.last_in == node->bclink.last_sent)
+                       goto unlock;
+
+               if (skb_queue_empty(&node->bclink.deferdq)) {
+                       node->bclink.oos_state = 1;
+                       goto unlock;
+               }
+
+               msg = buf_msg(skb_peek(&node->bclink.deferdq));
+               seqno = msg_seqno(msg);
+               next_in = mod(next_in + 1);
+               if (seqno != next_in)
+                       goto unlock;
+
+               /* Take in-sequence message from deferred queue & deliver it */
+               buf = __skb_dequeue(&node->bclink.deferdq);
+               goto receive;
+       }
+
+       /* Handle out-of-sequence broadcast message */
+       if (less(next_in, seqno)) {
+               deferred = tipc_link_defer_pkt(&node->bclink.deferdq,
+                                              buf);
+               bclink_update_last_sent(node, seqno);
+               buf = NULL;
+       }
+
+       tipc_bclink_lock(net);
+
+       if (deferred)
+               bcl->stats.deferred_recv++;
+       else
+               bcl->stats.duplicates++;
+
+       tipc_bclink_unlock(net);
+
+unlock:
+       tipc_node_unlock(node);
+       tipc_node_put(node);
+exit:
+       kfree_skb(buf);
+}
+
+u32 tipc_bclink_acks_missing(struct tipc_node *n_ptr)
+{
+       return (n_ptr->bclink.recv_permitted &&
+               (tipc_bclink_get_last_sent(n_ptr->net) != n_ptr->bclink.acked));
+}
+
+
+/**
+ * tipc_bcbearer_send - send a packet through the broadcast pseudo-bearer
+ *
+ * Send packet over as many bearers as necessary to reach all nodes
+ * that have joined the broadcast link.
+ *
+ * Returns 0 (packet sent successfully) under all circumstances,
+ * since the broadcast link's pseudo-bearer never blocks
+ */
+static int tipc_bcbearer_send(struct net *net, struct sk_buff *buf,
+                             struct tipc_bearer *unused1,
+                             struct tipc_media_addr *unused2)
+{
+       int bp_index;
+       struct tipc_msg *msg = buf_msg(buf);
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_bcbearer *bcbearer = tn->bcbearer;
+       struct tipc_bclink *bclink = tn->bclink;
+
+       /* Prepare broadcast link message for reliable transmission,
+        * if first time trying to send it;
+        * preparation is skipped for broadcast link protocol messages
+        * since they are sent in an unreliable manner and don't need it
+        */
+       if (likely(!msg_non_seq(buf_msg(buf)))) {
+               bcbuf_set_acks(buf, bclink->bcast_nodes.count);
+               msg_set_non_seq(msg, 1);
+               msg_set_mc_netid(msg, tn->net_id);
+               tn->bcl->stats.sent_info++;
+               if (WARN_ON(!bclink->bcast_nodes.count)) {
+                       dump_stack();
+                       return 0;
+               }
+       }
+
+       /* Send buffer over bearers until all targets reached */
+       bcbearer->remains = bclink->bcast_nodes;
+
+       for (bp_index = 0; bp_index < MAX_BEARERS; bp_index++) {
+               struct tipc_bearer *p = bcbearer->bpairs[bp_index].primary;
+               struct tipc_bearer *s = bcbearer->bpairs[bp_index].secondary;
+               struct tipc_bearer *bp[2] = {p, s};
+               struct tipc_bearer *b = bp[msg_link_selector(msg)];
+               struct sk_buff *tbuf;
+
+               if (!p)
+                       break; /* No more bearers to try */
+               if (!b)
+                       b = p;
+               tipc_nmap_diff(&bcbearer->remains, &b->nodes,
+                              &bcbearer->remains_new);
+               if (bcbearer->remains_new.count == bcbearer->remains.count)
+                       continue; /* Nothing added by bearer pair */
+
+               if (bp_index == 0) {
+                       /* Use original buffer for first bearer */
+                       tipc_bearer_send(net, b->identity, buf, &b->bcast_addr);
+               } else {
+                       /* Avoid concurrent buffer access */
+                       tbuf = pskb_copy_for_clone(buf, GFP_ATOMIC);
+                       if (!tbuf)
+                               break;
+                       tipc_bearer_send(net, b->identity, tbuf,
+                                        &b->bcast_addr);
+                       kfree_skb(tbuf); /* Bearer keeps a clone */
+               }
+               if (bcbearer->remains_new.count == 0)
+                       break; /* All targets reached */
+
+               bcbearer->remains = bcbearer->remains_new;
+       }
+
+       return 0;
+}
+
+/**
+ * tipc_bcbearer_sort - create sets of bearer pairs used by broadcast bearer
+ */
+void tipc_bcbearer_sort(struct net *net, struct tipc_node_map *nm_ptr,
+                       u32 node, bool action)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_bcbearer *bcbearer = tn->bcbearer;
+       struct tipc_bcbearer_pair *bp_temp = bcbearer->bpairs_temp;
+       struct tipc_bcbearer_pair *bp_curr;
+       struct tipc_bearer *b;
+       int b_index;
+       int pri;
+
+       tipc_bclink_lock(net);
+
+       if (action)
+               tipc_nmap_add(nm_ptr, node);
+       else
+               tipc_nmap_remove(nm_ptr, node);
+
+       /* Group bearers by priority (can assume max of two per priority) */
+       memset(bp_temp, 0, sizeof(bcbearer->bpairs_temp));
+
+       rcu_read_lock();
+       for (b_index = 0; b_index < MAX_BEARERS; b_index++) {
+               b = rcu_dereference_rtnl(tn->bearer_list[b_index]);
+               if (!b || !b->nodes.count)
+                       continue;
+
+               if (!bp_temp[b->priority].primary)
+                       bp_temp[b->priority].primary = b;
+               else
+                       bp_temp[b->priority].secondary = b;
+       }
+       rcu_read_unlock();
+
+       /* Create array of bearer pairs for broadcasting */
+       bp_curr = bcbearer->bpairs;
+       memset(bcbearer->bpairs, 0, sizeof(bcbearer->bpairs));
+
+       for (pri = TIPC_MAX_LINK_PRI; pri >= 0; pri--) {
+
+               if (!bp_temp[pri].primary)
+                       continue;
+
+               bp_curr->primary = bp_temp[pri].primary;
+
+               if (bp_temp[pri].secondary) {
+                       if (tipc_nmap_equal(&bp_temp[pri].primary->nodes,
+                                           &bp_temp[pri].secondary->nodes)) {
+                               bp_curr->secondary = bp_temp[pri].secondary;
+                       } else {
+                               bp_curr++;
+                               bp_curr->primary = bp_temp[pri].secondary;
+                       }
+               }
+
+               bp_curr++;
+       }
+
+       tipc_bclink_unlock(net);
+}
+
+static int __tipc_nl_add_bc_link_stat(struct sk_buff *skb,
+                                     struct tipc_stats *stats)
+{
+       int i;
+       struct nlattr *nest;
+
+       struct nla_map {
+               __u32 key;
+               __u32 val;
+       };
+
+       struct nla_map map[] = {
+               {TIPC_NLA_STATS_RX_INFO, stats->recv_info},
+               {TIPC_NLA_STATS_RX_FRAGMENTS, stats->recv_fragments},
+               {TIPC_NLA_STATS_RX_FRAGMENTED, stats->recv_fragmented},
+               {TIPC_NLA_STATS_RX_BUNDLES, stats->recv_bundles},
+               {TIPC_NLA_STATS_RX_BUNDLED, stats->recv_bundled},
+               {TIPC_NLA_STATS_TX_INFO, stats->sent_info},
+               {TIPC_NLA_STATS_TX_FRAGMENTS, stats->sent_fragments},
+               {TIPC_NLA_STATS_TX_FRAGMENTED, stats->sent_fragmented},
+               {TIPC_NLA_STATS_TX_BUNDLES, stats->sent_bundles},
+               {TIPC_NLA_STATS_TX_BUNDLED, stats->sent_bundled},
+               {TIPC_NLA_STATS_RX_NACKS, stats->recv_nacks},
+               {TIPC_NLA_STATS_RX_DEFERRED, stats->deferred_recv},
+               {TIPC_NLA_STATS_TX_NACKS, stats->sent_nacks},
+               {TIPC_NLA_STATS_TX_ACKS, stats->sent_acks},
+               {TIPC_NLA_STATS_RETRANSMITTED, stats->retransmitted},
+               {TIPC_NLA_STATS_DUPLICATES, stats->duplicates},
+               {TIPC_NLA_STATS_LINK_CONGS, stats->link_congs},
+               {TIPC_NLA_STATS_MAX_QUEUE, stats->max_queue_sz},
+               {TIPC_NLA_STATS_AVG_QUEUE, stats->queue_sz_counts ?
+                       (stats->accu_queue_sz / stats->queue_sz_counts) : 0}
+       };
+
+       nest = nla_nest_start(skb, TIPC_NLA_LINK_STATS);
+       if (!nest)
+               return -EMSGSIZE;
+
+       for (i = 0; i <  ARRAY_SIZE(map); i++)
+               if (nla_put_u32(skb, map[i].key, map[i].val))
+                       goto msg_full;
+
+       nla_nest_end(skb, nest);
+
+       return 0;
+msg_full:
+       nla_nest_cancel(skb, nest);
+
+       return -EMSGSIZE;
+}
+
+int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg)
+{
+       int err;
+       void *hdr;
+       struct nlattr *attrs;
+       struct nlattr *prop;
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_link *bcl = tn->bcl;
+
+       if (!bcl)
+               return 0;
+
+       tipc_bclink_lock(net);
+
+       hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
+                         NLM_F_MULTI, TIPC_NL_LINK_GET);
+       if (!hdr)
+               return -EMSGSIZE;
+
+       attrs = nla_nest_start(msg->skb, TIPC_NLA_LINK);
+       if (!attrs)
+               goto msg_full;
+
+       /* The broadcast link is always up */
+       if (nla_put_flag(msg->skb, TIPC_NLA_LINK_UP))
+               goto attr_msg_full;
+
+       if (nla_put_flag(msg->skb, TIPC_NLA_LINK_BROADCAST))
+               goto attr_msg_full;
+       if (nla_put_string(msg->skb, TIPC_NLA_LINK_NAME, bcl->name))
+               goto attr_msg_full;
+       if (nla_put_u32(msg->skb, TIPC_NLA_LINK_RX, bcl->next_in_no))
+               goto attr_msg_full;
+       if (nla_put_u32(msg->skb, TIPC_NLA_LINK_TX, bcl->next_out_no))
+               goto attr_msg_full;
+
+       prop = nla_nest_start(msg->skb, TIPC_NLA_LINK_PROP);
+       if (!prop)
+               goto attr_msg_full;
+       if (nla_put_u32(msg->skb, TIPC_NLA_PROP_WIN, bcl->window))
+               goto prop_msg_full;
+       nla_nest_end(msg->skb, prop);
+
+       err = __tipc_nl_add_bc_link_stat(msg->skb, &bcl->stats);
+       if (err)
+               goto attr_msg_full;
+
+       tipc_bclink_unlock(net);
+       nla_nest_end(msg->skb, attrs);
+       genlmsg_end(msg->skb, hdr);
+
+       return 0;
+
+prop_msg_full:
+       nla_nest_cancel(msg->skb, prop);
+attr_msg_full:
+       nla_nest_cancel(msg->skb, attrs);
+msg_full:
+       tipc_bclink_unlock(net);
+       genlmsg_cancel(msg->skb, hdr);
+
+       return -EMSGSIZE;
+}
+
+int tipc_bclink_reset_stats(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_link *bcl = tn->bcl;
+
+       if (!bcl)
+               return -ENOPROTOOPT;
+
+       tipc_bclink_lock(net);
+       memset(&bcl->stats, 0, sizeof(bcl->stats));
+       tipc_bclink_unlock(net);
+       return 0;
+}
+
+int tipc_bclink_set_queue_limits(struct net *net, u32 limit)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_link *bcl = tn->bcl;
+
+       if (!bcl)
+               return -ENOPROTOOPT;
+       if ((limit < TIPC_MIN_LINK_WIN) || (limit > TIPC_MAX_LINK_WIN))
+               return -EINVAL;
+
+       tipc_bclink_lock(net);
+       tipc_link_set_queue_limits(bcl, limit);
+       tipc_bclink_unlock(net);
+       return 0;
+}
+
+int tipc_bclink_init(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+       struct tipc_bcbearer *bcbearer;
+       struct tipc_bclink *bclink;
+       struct tipc_link *bcl;
+
+       bcbearer = kzalloc(sizeof(*bcbearer), GFP_ATOMIC);
+       if (!bcbearer)
+               return -ENOMEM;
+
+       bclink = kzalloc(sizeof(*bclink), GFP_ATOMIC);
+       if (!bclink) {
+               kfree(bcbearer);
+               return -ENOMEM;
+       }
+
+       bcl = &bclink->link;
+       bcbearer->bearer.media = &bcbearer->media;
+       bcbearer->media.send_msg = tipc_bcbearer_send;
+       sprintf(bcbearer->media.name, "tipc-broadcast");
+
+       spin_lock_init(&bclink->lock);
+       __skb_queue_head_init(&bcl->transmq);
+       __skb_queue_head_init(&bcl->backlogq);
+       __skb_queue_head_init(&bcl->deferdq);
+       skb_queue_head_init(&bcl->wakeupq);
+       bcl->next_out_no = 1;
+       spin_lock_init(&bclink->node.lock);
+       __skb_queue_head_init(&bclink->arrvq);
+       skb_queue_head_init(&bclink->inputq);
+       bcl->owner = &bclink->node;
+       bcl->owner->net = net;
+       bcl->mtu = MAX_PKT_DEFAULT_MCAST;
+       tipc_link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT);
+       bcl->bearer_id = MAX_BEARERS;
+       rcu_assign_pointer(tn->bearer_list[MAX_BEARERS], &bcbearer->bearer);
+       bcl->state = WORKING_WORKING;
+       bcl->pmsg = (struct tipc_msg *)&bcl->proto_msg;
+       msg_set_prevnode(bcl->pmsg, tn->own_addr);
+       strlcpy(bcl->name, tipc_bclink_name, TIPC_MAX_LINK_NAME);
+       tn->bcbearer = bcbearer;
+       tn->bclink = bclink;
+       tn->bcl = bcl;
+       return 0;
+}
+
+void tipc_bclink_stop(struct net *net)
+{
+       struct tipc_net *tn = net_generic(net, tipc_net_id);
+
+       tipc_bclink_lock(net);
+       tipc_link_purge_queues(tn->bcl);
+       tipc_bclink_unlock(net);
+
+       RCU_INIT_POINTER(tn->bearer_list[BCBEARER], NULL);
+       synchronize_net();
+       kfree(tn->bcbearer);
+       kfree(tn->bclink);
+}
+
+/**
+ * tipc_nmap_add - add a node to a node map
+ */
+static void tipc_nmap_add(struct tipc_node_map *nm_ptr, u32 node)
+{
+       int n = tipc_node(node);
+       int w = n / WSIZE;
+       u32 mask = (1 << (n % WSIZE));
+
+       if ((nm_ptr->map[w] & mask) == 0) {
+               nm_ptr->count++;
+               nm_ptr->map[w] |= mask;
+       }
+}
+
+/**
+ * tipc_nmap_remove - remove a node from a node map
+ */
+static void tipc_nmap_remove(struct tipc_node_map *nm_ptr, u32 node)
+{
+       int n = tipc_node(node);
+       int w = n / WSIZE;
+       u32 mask = (1 << (n % WSIZE));
+
+       if ((nm_ptr->map[w] & mask) != 0) {
+               nm_ptr->map[w] &= ~mask;
+               nm_ptr->count--;
+       }
+}
+
+/**
+ * tipc_nmap_diff - find differences between node maps
+ * @nm_a: input node map A
+ * @nm_b: input node map B
+ * @nm_diff: output node map A-B (i.e. nodes of A that are not in B)
+ */
+static void tipc_nmap_diff(struct tipc_node_map *nm_a,
+                          struct tipc_node_map *nm_b,
+                          struct tipc_node_map *nm_diff)
+{
+       int stop = ARRAY_SIZE(nm_a->map);
+       int w;
+       int b;
+       u32 map;
+
+       memset(nm_diff, 0, sizeof(*nm_diff));
+       for (w = 0; w < stop; w++) {
+               map = nm_a->map[w] ^ (nm_a->map[w] & nm_b->map[w]);
+               nm_diff->map[w] = map;
+               if (map != 0) {
+                       for (b = 0 ; b < WSIZE; b++) {
+                               if (map & (1 << b))
+                                       nm_diff->count++;
+                       }
+               }
+       }
+}