[TIPC] Initial merge

TIPC (Transparent Inter Process Communication) is a protocol designed for
intra cluster communication. For more information see
http://tipc.sourceforge.net

Signed-off-by: Per Liden <per.liden@nospam.ericsson.com>

1 files changed, 803 insertions, 0 deletions

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
new file mode 100644
index 000000000000..35ca90667a59
--- /dev/null
+++ b/net/tipc/bcast.c
@@ -0,0 +1,803 @@
+/*
+ * net/tipc/bcast.c: TIPC broadcast code
+ *     
+ * Copyright (c) 2003-2005, Ericsson Research Canada
+ * Copyright (c) 2004, Intel Corporation.
+ * Copyright (c) 2005, Wind River Systems
+ * Copyright (c) 2005-2006, Ericsson AB
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this 
+ * list of conditions and the following disclaimer.
+ * 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.
+ * 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.
+ *
+ * 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 "core.h"
+#include "msg.h"
+#include "dbg.h"
+#include "link.h"
+#include "net.h"
+#include "node.h"
+#include "port.h"
+#include "addr.h"
+#include "node_subscr.h"
+#include "name_distr.h"
+#include "bearer.h"
+#include "name_table.h"
+#include "bcast.h"
+
+
+#define MAX_PKT_DEFAULT_MCAST 1500      /* bcast link max packet size (fixed) */
+
+#define BCLINK_WIN_DEFAULT 20           /* bcast link window size (default) */
+
+#define BCLINK_LOG_BUF_SIZE 0
+
+/**
+ * struct bcbearer_pair - a pair of bearers used by broadcast link
+ * @primary: pointer to primary bearer
+ * @secondary: pointer to secondary bearer
+ * 
+ * Bearers must have same priority and same set of reachable destinations 
+ * to be paired.
+ */
+
+struct bcbearer_pair {
+        struct bearer *primary;
+        struct bearer *secondary;
+};
+
+/**
+ * struct bcbearer - bearer used by broadcast link
+ * @bearer: (non-standard) broadcast bearer structure
+ * @media: (non-standard) broadcast media structure
+ * @bpairs: array of bearer pairs
+ * @bpairs_temp: array of bearer pairs used during creation of "bpairs"
+ */
+
+struct bcbearer {
+        struct bearer bearer;
+        struct media media;
+        struct bcbearer_pair bpairs[MAX_BEARERS];
+        struct bcbearer_pair bpairs_temp[TIPC_NUM_LINK_PRI];
+};
+
+/**
+ * struct bclink - link used for broadcast messages
+ * @link: (non-standard) broadcast link structure
+ * @node: (non-standard) node structure representing b'cast link's peer node
+ * 
+ * Handles sequence numbering, fragmentation, bundling, etc.
+ */
+
+struct bclink {
+        struct link link;
+        struct node node;
+};
+
+
+static struct bcbearer *bcbearer = NULL;
+static struct bclink *bclink = NULL;
+static struct link *bcl = NULL;
+static spinlock_t bc_lock = SPIN_LOCK_UNLOCKED;
+
+char bc_link_name[] = "multicast-link";
+
+
+static inline u32 buf_seqno(struct sk_buff *buf)
+{
+        return msg_seqno(buf_msg(buf));
+} 
+
+static inline u32 bcbuf_acks(struct sk_buff *buf)
+{
+        return (u32)TIPC_SKB_CB(buf)->handle;
+}
+
+static inline void bcbuf_set_acks(struct sk_buff *buf, u32 acks)
+{
+        TIPC_SKB_CB(buf)->handle = (void *)acks;
+}
+
+static inline void bcbuf_decr_acks(struct sk_buff *buf)
+{
+        bcbuf_set_acks(buf, bcbuf_acks(buf) - 1);
+}
+
+
+/** 
+ * bclink_set_gap - set gap according to contents of current deferred pkt queue
+ * 
+ * Called with 'node' locked, bc_lock unlocked
+ */
+
+static inline void bclink_set_gap(struct node *n_ptr)
+{
+        struct sk_buff *buf = n_ptr->bclink.deferred_head;
+
+        n_ptr->bclink.gap_after = n_ptr->bclink.gap_to =
+                mod(n_ptr->bclink.last_in);
+        if (unlikely(buf != NULL))
+                n_ptr->bclink.gap_to = mod(buf_seqno(buf) - 1);
+}
+
+/** 
+ * bclink_ack_allowed - test if ACK or NACK message can be sent at this moment
+ * 
+ * This mechanism endeavours to prevent all nodes in network from trying
+ * to ACK or NACK at the same time.
+ * 
+ * Note: TIPC uses a different trigger to distribute ACKs than it does to
+ *       distribute NACKs, but tries to use the same spacing (divide by 16). 
+ */
+
+static inline int bclink_ack_allowed(u32 n)
+{
+        return((n % TIPC_MIN_LINK_WIN) == tipc_own_tag);
+}
+
+
+/** 
+ * 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 'node' locked, bc_lock unlocked
+ */
+
+static void bclink_retransmit_pkt(u32 after, u32 to)
+{
+        struct sk_buff *buf;
+
+        spin_lock_bh(&bc_lock);
+        buf = bcl->first_out;
+        while (buf && less_eq(buf_seqno(buf), after)) {
+                buf = buf->next;                
+        }
+        if (buf != NULL)
+                link_retransmit(bcl, buf, mod(to - after));
+        spin_unlock_bh(&bc_lock);              
+}
+
+/** 
+ * bclink_acknowledge - handle acknowledgement of broadcast packets
+ * @n_ptr: node that sent acknowledgement info
+ * @acked: broadcast sequence # that has been acknowledged
+ * 
+ * Node is locked, bc_lock unlocked.
+ */
+
+void bclink_acknowledge(struct node *n_ptr, u32 acked)
+{
+        struct sk_buff *crs;
+        struct sk_buff *next;
+        unsigned int released = 0;
+
+        if (less_eq(acked, n_ptr->bclink.acked))
+                return;
+
+        spin_lock_bh(&bc_lock);
+
+        /* Skip over packets that node has previously acknowledged */
+
+        crs = bcl->first_out;
+        while (crs && less_eq(buf_seqno(crs), n_ptr->bclink.acked)) {
+                crs = crs->next;
+        }
+
+        /* Update packets that node is now acknowledging */
+
+        while (crs && less_eq(buf_seqno(crs), acked)) {
+                next = crs->next;
+                bcbuf_decr_acks(crs);
+                if (bcbuf_acks(crs) == 0) {
+                        bcl->first_out = next;
+                        bcl->out_queue_size--;
+                        buf_discard(crs);
+                        released = 1;
+                }
+                crs = next;
+        }
+        n_ptr->bclink.acked = acked;
+
+        /* Try resolving broadcast link congestion, if necessary */
+
+        if (unlikely(bcl->next_out))
+                link_push_queue(bcl);
+        if (unlikely(released && !list_empty(&bcl->waiting_ports)))
+                link_wakeup_ports(bcl, 0);
+        spin_unlock_bh(&bc_lock);
+}
+
+/** 
+ * bclink_send_ack - unicast an ACK msg
+ * 
+ * net_lock and node lock set
+ */
+
+static void bclink_send_ack(struct node *n_ptr)
+{
+        struct link *l_ptr = n_ptr->active_links[n_ptr->addr & 1];
+
+        if (l_ptr != NULL)
+                link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
+}
+
+/** 
+ * bclink_send_nack- broadcast a NACK msg
+ * 
+ * net_lock and node lock set
+ */
+
+static void bclink_send_nack(struct node *n_ptr)
+{
+        struct sk_buff *buf;
+        struct tipc_msg *msg;
+
+        if (!less(n_ptr->bclink.gap_after, n_ptr->bclink.gap_to))
+                return;
+
+        buf = buf_acquire(INT_H_SIZE);
+        if (buf) {
+                msg = buf_msg(buf);
+                msg_init(msg, BCAST_PROTOCOL, STATE_MSG,
+                         TIPC_OK, INT_H_SIZE, n_ptr->addr);
+                msg_set_mc_netid(msg, tipc_net_id);
+                msg_set_bcast_ack(msg, mod(n_ptr->bclink.last_in)); 
+                msg_set_bcgap_after(msg, n_ptr->bclink.gap_after);
+                msg_set_bcgap_to(msg, n_ptr->bclink.gap_to);
+                msg_set_bcast_tag(msg, tipc_own_tag);
+
+                if (bearer_send(&bcbearer->bearer, buf, 0)) {
+                        bcl->stats.sent_nacks++;
+                        buf_discard(buf);
+                } else {
+                        bearer_schedule(bcl->b_ptr, bcl);
+                        bcl->proto_msg_queue = buf;
+                        bcl->stats.bearer_congs++;
+                }
+
+                /* 
+                 * Ensure we doesn't send another NACK msg to the node
+                 * until 16 more deferred messages arrive from it
+                 * (i.e. helps prevent all nodes from NACK'ing at same time)
+                 */
+                
+                n_ptr->bclink.nack_sync = tipc_own_tag;
+        }
+}
+
+/** 
+ * bclink_check_gap - send a NACK if a sequence gap exists
+ *
+ * net_lock and node lock set
+ */
+
+void bclink_check_gap(struct node *n_ptr, u32 last_sent)
+{
+        if (!n_ptr->bclink.supported ||
+            less_eq(last_sent, mod(n_ptr->bclink.last_in)))
+                return;
+
+        bclink_set_gap(n_ptr);
+        if (n_ptr->bclink.gap_after == n_ptr->bclink.gap_to)
+                n_ptr->bclink.gap_to = last_sent;
+        bclink_send_nack(n_ptr);
+}
+
+/** 
+ * bclink_peek_nack - process a NACK msg meant for another node
+ * 
+ * Only net_lock set.
+ */
+
+void bclink_peek_nack(u32 dest, u32 sender_tag, u32 gap_after, u32 gap_to)
+{
+        struct node *n_ptr = node_find(dest);
+        u32 my_after, my_to;
+
+        if (unlikely(!n_ptr || !node_is_up(n_ptr)))
+                return;
+        node_lock(n_ptr);
+        /*
+         * Modify gap to suppress unnecessary NACKs from this node
+         */
+        my_after = n_ptr->bclink.gap_after;
+        my_to = n_ptr->bclink.gap_to;
+
+        if (less_eq(gap_after, my_after)) {
+                if (less(my_after, gap_to) && less(gap_to, my_to))
+                        n_ptr->bclink.gap_after = gap_to;
+                else if (less_eq(my_to, gap_to))
+                        n_ptr->bclink.gap_to = n_ptr->bclink.gap_after;
+        } else if (less_eq(gap_after, my_to)) {
+                if (less_eq(my_to, gap_to))
+                        n_ptr->bclink.gap_to = gap_after;
+        } else {
+                /* 
+                 * Expand gap if missing bufs not in deferred queue:
+                 */
+                struct sk_buff *buf = n_ptr->bclink.deferred_head;
+                u32 prev = n_ptr->bclink.gap_to;
+
+                for (; buf; buf = buf->next) {
+                        u32 seqno = buf_seqno(buf);
+
+                        if (mod(seqno - prev) != 1)
+                                buf = NULL;
+                        if (seqno == gap_after)
+                                break;
+                        prev = seqno;
+                }
+                if (buf == NULL)
+                        n_ptr->bclink.gap_to = gap_after;
+        }
+        /*
+         * Some nodes may send a complementary NACK now:
+         */ 
+        if (bclink_ack_allowed(sender_tag + 1)) {
+                if (n_ptr->bclink.gap_to != n_ptr->bclink.gap_after) {
+                        bclink_send_nack(n_ptr);
+                        bclink_set_gap(n_ptr);
+                }
+        }
+        node_unlock(n_ptr);
+}
+
+/**
+ * bclink_send_msg - broadcast a packet to all nodes in cluster
+ */
+
+int bclink_send_msg(struct sk_buff *buf)
+{
+        int res;
+
+        spin_lock_bh(&bc_lock);
+
+        res = link_send_buf(bcl, buf);
+        if (unlikely(res == -ELINKCONG))
+                buf_discard(buf);
+        else
+                bcl->stats.sent_info++;
+
+        if (bcl->out_queue_size > bcl->stats.max_queue_sz)
+                bcl->stats.max_queue_sz = bcl->out_queue_size;
+        bcl->stats.queue_sz_counts++;
+        bcl->stats.accu_queue_sz += bcl->out_queue_size;
+
+        spin_unlock_bh(&bc_lock);
+        return res;
+}
+
+/**
+ * bclink_recv_pkt - receive a broadcast packet, and deliver upwards
+ * 
+ * net_lock is read_locked, no other locks set
+ */
+
+void bclink_recv_pkt(struct sk_buff *buf)
+{        
+        struct tipc_msg *msg = buf_msg(buf);
+        struct node* node = node_find(msg_prevnode(msg));
+        u32 next_in;
+        u32 seqno;
+        struct sk_buff *deferred;
+
+        msg_dbg(msg, "<BC<<<");
+
+        if (unlikely(!node || !node_is_up(node) || !node->bclink.supported || 
+                     (msg_mc_netid(msg) != tipc_net_id))) {
+                buf_discard(buf);
+                return;
+        }
+
+        if (unlikely(msg_user(msg) == BCAST_PROTOCOL)) {
+                msg_dbg(msg, "<BCNACK<<<");
+                if (msg_destnode(msg) == tipc_own_addr) {
+                        node_lock(node);
+                        bclink_acknowledge(node, msg_bcast_ack(msg));
+                        node_unlock(node);
+                        bcl->stats.recv_nacks++;
+                        bclink_retransmit_pkt(msg_bcgap_after(msg),
+                                              msg_bcgap_to(msg));
+                } else {
+                        bclink_peek_nack(msg_destnode(msg),
+                                         msg_bcast_tag(msg),
+                                         msg_bcgap_after(msg),
+                                         msg_bcgap_to(msg));
+                }
+                buf_discard(buf);
+                return;
+        }
+
+        node_lock(node);
+receive:
+        deferred = node->bclink.deferred_head;
+        next_in = mod(node->bclink.last_in + 1);
+        seqno = msg_seqno(msg);
+
+        if (likely(seqno == next_in)) {
+                bcl->stats.recv_info++;
+                node->bclink.last_in++;
+                bclink_set_gap(node);
+                if (unlikely(bclink_ack_allowed(seqno))) {
+                        bclink_send_ack(node);
+                        bcl->stats.sent_acks++;
+                }
+                if (likely(msg_isdata(msg))) {
+                        node_unlock(node);
+                        port_recv_mcast(buf, NULL);
+                } else if (msg_user(msg) == MSG_BUNDLER) {
+                        bcl->stats.recv_bundles++;
+                        bcl->stats.recv_bundled += msg_msgcnt(msg);
+                        node_unlock(node);
+                        link_recv_bundle(buf);
+                } else if (msg_user(msg) == MSG_FRAGMENTER) {
+                        bcl->stats.recv_fragments++;
+                        if (link_recv_fragment(&node->bclink.defragm,
+                                               &buf, &msg))
+                                bcl->stats.recv_fragmented++;
+                        node_unlock(node);
+                        net_route_msg(buf);
+                } else {
+                        node_unlock(node);
+                        net_route_msg(buf);
+                }
+                if (deferred && (buf_seqno(deferred) == mod(next_in + 1))) {
+                        node_lock(node);
+                        buf = deferred;
+                        msg = buf_msg(buf);
+                        node->bclink.deferred_head = deferred->next;
+                        goto receive;
+                }
+                return;
+        } else if (less(next_in, seqno)) {
+                u32 gap_after = node->bclink.gap_after;
+                u32 gap_to = node->bclink.gap_to;
+
+                if (link_defer_pkt(&node->bclink.deferred_head,
+                                   &node->bclink.deferred_tail,
+                                   buf)) {
+                        node->bclink.nack_sync++;
+                        bcl->stats.deferred_recv++;
+                        if (seqno == mod(gap_after + 1))
+                                node->bclink.gap_after = seqno;
+                        else if (less(gap_after, seqno) && less(seqno, gap_to))
+                                node->bclink.gap_to = seqno;
+                }
+                if (bclink_ack_allowed(node->bclink.nack_sync)) {
+                        if (gap_to != gap_after)
+                                bclink_send_nack(node);
+                        bclink_set_gap(node);
+                }
+        } else {
+                bcl->stats.duplicates++;
+                buf_discard(buf);
+        }
+        node_unlock(node);
+}
+
+u32 bclink_get_last_sent(void)
+{
+        u32 last_sent = mod(bcl->next_out_no - 1);
+
+        if (bcl->next_out)
+                last_sent = mod(buf_seqno(bcl->next_out) - 1);
+        return last_sent;
+}
+
+u32 bclink_acks_missing(struct node *n_ptr)
+{
+        return (n_ptr->bclink.supported &&
+                (bclink_get_last_sent() != n_ptr->bclink.acked));
+}
+
+
+/**
+ * bcbearer_send - send a packet through the broadcast pseudo-bearer
+ * 
+ * Send through as many bearers as necessary to reach all nodes
+ * that support TIPC multicasting.
+ * 
+ * Returns 0 if packet sent successfully, non-zero if not
+ */
+
+int bcbearer_send(struct sk_buff *buf,
+                  struct tipc_bearer *unused1,
+                  struct tipc_media_addr *unused2)
+{
+        static int send_count = 0;
+
+        struct node_map remains;
+        struct node_map remains_new;
+        int bp_index;
+        int swap_time;
+
+        /* Prepare buffer for broadcasting (if first time trying to send it) */
+
+        if (likely(!msg_non_seq(buf_msg(buf)))) {
+                struct tipc_msg *msg;
+
+                assert(cluster_bcast_nodes.count != 0);
+                bcbuf_set_acks(buf, cluster_bcast_nodes.count);
+                msg = buf_msg(buf);
+                msg_set_non_seq(msg);
+                msg_set_mc_netid(msg, tipc_net_id);
+        }
+
+        /* Determine if bearer pairs should be swapped following this attempt */
+
+        if ((swap_time = (++send_count >= 10)))
+                send_count = 0;
+
+        /* Send buffer over bearers until all targets reached */
+        
+        remains = cluster_bcast_nodes;
+
+        for (bp_index = 0; bp_index < MAX_BEARERS; bp_index++) {
+                struct bearer *p = bcbearer->bpairs[bp_index].primary;
+                struct bearer *s = bcbearer->bpairs[bp_index].secondary;
+
+                if (!p)
+                        break;  /* no more bearers to try */
+
+                nmap_diff(&remains, &p->nodes, &remains_new);
+                if (remains_new.count == remains.count)
+                        continue;       /* bearer pair doesn't add anything */
+
+                if (!p->publ.blocked &&
+                    !p->media->send_msg(buf, &p->publ, &p->media->bcast_addr)) {
+                        if (swap_time && s && !s->publ.blocked)
+                                goto swap;
+                        else
+                                goto update;
+                }
+
+                if (!s || s->publ.blocked ||
+                    s->media->send_msg(buf, &s->publ, &s->media->bcast_addr))
+                        continue;       /* unable to send using bearer pair */
+swap:
+                bcbearer->bpairs[bp_index].primary = s;
+                bcbearer->bpairs[bp_index].secondary = p;
+update:
+                if (remains_new.count == 0)
+                        return TIPC_OK;
+
+                remains = remains_new;
+        }
+        
+        /* Unable to reach all targets */
+
+        bcbearer->bearer.publ.blocked = 1;
+        bcl->stats.bearer_congs++;
+        return ~TIPC_OK;
+}
+
+/**
+ * bcbearer_sort - create sets of bearer pairs used by broadcast bearer
+ */
+
+void bcbearer_sort(void)
+{
+        struct bcbearer_pair *bp_temp = bcbearer->bpairs_temp;
+        struct bcbearer_pair *bp_curr;
+        int b_index;
+        int pri;
+
+        spin_lock_bh(&bc_lock);
+
+        /* Group bearers by priority (can assume max of two per priority) */
+
+        memset(bp_temp, 0, sizeof(bcbearer->bpairs_temp));
+
+        for (b_index = 0; b_index < MAX_BEARERS; b_index++) {
+                struct bearer *b = &bearers[b_index];
+
+                if (!b->active || !b->nodes.count)
+                        continue;
+
+                if (!bp_temp[b->priority].primary)
+                        bp_temp[b->priority].primary = b;
+                else
+                        bp_temp[b->priority].secondary = b;
+        }
+
+        /* Create array of bearer pairs for broadcasting */
+
+        bp_curr = bcbearer->bpairs;
+        memset(bcbearer->bpairs, 0, sizeof(bcbearer->bpairs));
+
+        for (pri = (TIPC_NUM_LINK_PRI - 1); pri >= 0; pri--) {
+
+                if (!bp_temp[pri].primary)
+                        continue;
+
+                bp_curr->primary = bp_temp[pri].primary;
+
+                if (bp_temp[pri].secondary) {
+                        if (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++;
+        }
+
+        spin_unlock_bh(&bc_lock);
+}
+
+/**
+ * bcbearer_push - resolve bearer congestion
+ * 
+ * Forces bclink to push out any unsent packets, until all packets are gone
+ * or congestion reoccurs.
+ * No locks set when function called
+ */
+
+void bcbearer_push(void)
+{
+        struct bearer *b_ptr;
+
+        spin_lock_bh(&bc_lock);
+        b_ptr = &bcbearer->bearer;
+        if (b_ptr->publ.blocked) {
+                b_ptr->publ.blocked = 0;
+                bearer_lock_push(b_ptr);
+        }
+        spin_unlock_bh(&bc_lock);
+}
+
+
+int bclink_stats(char *buf, const u32 buf_size)
+{
+        struct print_buf pb;
+
+        if (!bcl)
+                return 0;
+
+        printbuf_init(&pb, buf, buf_size);
+
+        spin_lock_bh(&bc_lock);
+
+        tipc_printf(&pb, "Link <%s>\n"
+                         "  Window:%u packets\n", 
+                    bcl->name, bcl->queue_limit[0]);
+        tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n", 
+                    bcl->stats.recv_info,
+                    bcl->stats.recv_fragments,
+                    bcl->stats.recv_fragmented,
+                    bcl->stats.recv_bundles,
+                    bcl->stats.recv_bundled);
+        tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n", 
+                    bcl->stats.sent_info,
+                    bcl->stats.sent_fragments,
+                    bcl->stats.sent_fragmented, 
+                    bcl->stats.sent_bundles,
+                    bcl->stats.sent_bundled);
+        tipc_printf(&pb, "  RX naks:%u defs:%u dups:%u\n", 
+                    bcl->stats.recv_nacks,
+                    bcl->stats.deferred_recv, 
+                    bcl->stats.duplicates);
+        tipc_printf(&pb, "  TX naks:%u acks:%u dups:%u\n", 
+                    bcl->stats.sent_nacks, 
+                    bcl->stats.sent_acks, 
+                    bcl->stats.retransmitted);
+        tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
+                    bcl->stats.bearer_congs,
+                    bcl->stats.link_congs,
+                    bcl->stats.max_queue_sz,
+                    bcl->stats.queue_sz_counts
+                    ? (bcl->stats.accu_queue_sz / bcl->stats.queue_sz_counts)
+                    : 0);
+
+        spin_unlock_bh(&bc_lock);
+        return printbuf_validate(&pb);
+}
+
+int bclink_reset_stats(void)
+{
+        if (!bcl)
+                return -ENOPROTOOPT;
+
+        spin_lock_bh(&bc_lock);
+        memset(&bcl->stats, 0, sizeof(bcl->stats));
+        spin_unlock_bh(&bc_lock);
+        return TIPC_OK;
+}
+
+int bclink_set_queue_limits(u32 limit)
+{
+        if (!bcl)
+                return -ENOPROTOOPT;
+        if ((limit < TIPC_MIN_LINK_WIN) || (limit > TIPC_MAX_LINK_WIN))
+                return -EINVAL;
+
+        spin_lock_bh(&bc_lock);
+        link_set_queue_limits(bcl, limit);
+        spin_unlock_bh(&bc_lock);
+        return TIPC_OK;
+}
+
+int bclink_init(void)
+{
+        bcbearer = kmalloc(sizeof(*bcbearer), GFP_ATOMIC);
+        bclink = kmalloc(sizeof(*bclink), GFP_ATOMIC);
+        if (!bcbearer || !bclink) {
+ nomem:
+                warn("Memory squeeze; Failed to create multicast link\n");
+                kfree(bcbearer);
+                bcbearer = NULL;
+                kfree(bclink);
+                bclink = NULL;
+                return -ENOMEM;
+        }
+
+        memset(bcbearer, 0, sizeof(struct bcbearer));
+        INIT_LIST_HEAD(&bcbearer->bearer.cong_links);
+        bcbearer->bearer.media = &bcbearer->media;
+        bcbearer->media.send_msg = bcbearer_send;
+        sprintf(bcbearer->media.name, "tipc-multicast");
+
+        bcl = &bclink->link;
+        memset(bclink, 0, sizeof(struct bclink));
+        INIT_LIST_HEAD(&bcl->waiting_ports);
+        bcl->next_out_no = 1;
+        bclink->node.lock =  SPIN_LOCK_UNLOCKED;        
+        bcl->owner = &bclink->node;
+        bcl->max_pkt = MAX_PKT_DEFAULT_MCAST;
+        link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT);
+        bcl->b_ptr = &bcbearer->bearer;
+        bcl->state = WORKING_WORKING;
+        sprintf(bcl->name, bc_link_name);
+
+        if (BCLINK_LOG_BUF_SIZE) {
+                char *pb = kmalloc(BCLINK_LOG_BUF_SIZE, GFP_ATOMIC);
+
+                if (!pb)
+                        goto nomem;
+                printbuf_init(&bcl->print_buf, pb, BCLINK_LOG_BUF_SIZE);
+        }
+
+        return TIPC_OK;
+}
+
+void bclink_stop(void)
+{
+        spin_lock_bh(&bc_lock);
+        if (bcbearer) {
+                link_stop(bcl);
+                if (BCLINK_LOG_BUF_SIZE)
+                        kfree(bcl->print_buf.buf);
+                bcl = NULL;
+                kfree(bclink);
+                bclink = NULL;
+                kfree(bcbearer);
+                bcbearer = NULL;
+        }
+        spin_unlock_bh(&bc_lock);
+}
+