/*
 * net/tipc/bcast.c: TIPC broadcast code
 *
 * Copyright (c) 2004-2006, 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 "core.h"
#include "link.h"
#include "port.h"
#include "bcast.h"
#include "name_distr.h"

#define MAX_PKT_DEFAULT_MCAST 1500      /* bcast link max packet size (fixed) */

#define BCLINK_WIN_DEFAULT 20           /* bcast link window size (default) */

/**
 * struct tipc_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 tipc_bcbearer_pair {
        struct tipc_bearer *primary;
        struct tipc_bearer *secondary;
};

/**
 * struct tipc_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: temporary array of bearer pairs used by tipc_bcbearer_sort()
 * @remains: temporary node map used by tipc_bcbearer_send()
 * @remains_new: temporary node map used tipc_bcbearer_send()
 *
 * Note: The fields labelled "temporary" are incorporated into the bearer
 * to avoid consuming potentially limited stack space through the use of
 * large local variables within multicast routines.  Concurrent access is
 * prevented through use of the spinlock "bc_lock".
 */
struct tipc_bcbearer {
        struct tipc_bearer bearer;
        struct tipc_media media;
        struct tipc_bcbearer_pair bpairs[MAX_BEARERS];
        struct tipc_bcbearer_pair bpairs_temp[TIPC_MAX_LINK_PRI + 1];
        struct tipc_node_map remains;
        struct tipc_node_map remains_new;
};

/**
 * struct tipc_bclink - link used for broadcast messages
 * @link: (non-standard) broadcast link structure
 * @node: (non-standard) node structure representing b'cast link's peer node
 * @bcast_nodes: map of broadcast-capable nodes
 * @retransmit_to: node that most recently requested a retransmit
 *
 * Handles sequence numbering, fragmentation, bundling, etc.
 */
struct tipc_bclink {
        struct tipc_link link;
        struct tipc_node node;
        struct tipc_node_map bcast_nodes;
        struct tipc_node *retransmit_to;
};

static struct tipc_bcbearer bcast_bearer;
static struct tipc_bclink bcast_link;

static struct tipc_bcbearer *bcbearer = &bcast_bearer;
static struct tipc_bclink *bclink = &bcast_link;
static struct tipc_link *bcl = &bcast_link.link;

static DEFINE_SPINLOCK(bc_lock);

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 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(u32 addr)
{
        spin_lock_bh(&bc_lock);
        tipc_nmap_add(&bclink->bcast_nodes, addr);
        spin_unlock_bh(&bc_lock);
}

void tipc_bclink_remove_node(u32 addr)
{
        spin_lock_bh(&bc_lock);
        tipc_nmap_remove(&bclink->bcast_nodes, addr);
        spin_unlock_bh(&bc_lock);
}

static void bclink_set_last_sent(void)
{
        if (bcl->next_out)
                bcl->fsm_msg_cnt = mod(buf_seqno(bcl->next_out) - 1);
        else
                bcl->fsm_msg_cnt = mod(bcl->next_out_no - 1);
}

u32 tipc_bclink_get_last_sent(void)
{
        return 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 bc_lock locked
 */
struct tipc_node *tipc_bclink_retransmit_to(void)
{
        return 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 bc_lock locked
 */
static void bclink_retransmit_pkt(u32 after, u32 to)
{
        struct sk_buff *buf;

        buf = bcl->first_out;
        while (buf && less_eq(buf_seqno(buf), after))
                buf = buf->next;
        tipc_link_retransmit(bcl, buf, mod(to - after));
}

/**
 * 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, bc_lock unlocked.
 */
void tipc_bclink_acknowledge(struct tipc_node *n_ptr, u32 acked)
{
        struct sk_buff *crs;
        struct sk_buff *next;
        unsigned int released = 0;

        spin_lock_bh(&bc_lock);

        /* Bail out if tx queue is empty (no clean up is required) */
        crs = bcl->first_out;
        if (!crs)
                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 (bclink->bcast_nodes.count)
                        acked = bcl->fsm_msg_cnt;
                else
                        acked = 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(crs)) ||
                    less(bcl->fsm_msg_cnt, acked) ||
                    less_eq(acked, n_ptr->bclink.acked))
                        goto exit;
        }

        /* Skip over packets that node has previously acknowledged */
        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;

                if (crs != bcl->next_out)
                        bcbuf_decr_acks(crs);
                else {
                        bcbuf_set_acks(crs, 0);
                        bcl->next_out = next;
                        bclink_set_last_sent();
                }

                if (bcbuf_acks(crs) == 0) {
                        bcl->first_out = next;
                        bcl->out_queue_size--;
                        kfree_skb(crs);
                        released = 1;
                }
                crs = next;
        }
        n_ptr->bclink.acked = acked;

        /* Try resolving broadcast link congestion, if necessary */

        if (unlikely(bcl->next_out)) {
                tipc_link_push_queue(bcl);
                bclink_set_last_sent();
        }
        if (unlikely(released && !list_empty(&bcl->waiting_ports)))
                tipc_link_wakeup_ports(bcl, 0);
exit:
        spin_unlock_bh(&bc_lock);
}

/**
 * tipc_bclink_update_link_state - update broadcast link state
 *
 * tipc_net_lock and node lock set
 */
void tipc_bclink_update_link_state(struct tipc_node *n_ptr, u32 last_sent)
{
        struct sk_buff *buf;

        /* 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);

                tipc_msg_init(msg, BCAST_PROTOCOL, STATE_MSG,
                              INT_H_SIZE, n_ptr->addr);
                msg_set_non_seq(msg, 1);
                msg_set_mc_netid(msg, tipc_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, n_ptr->bclink.deferred_head
                                 ? buf_seqno(n_ptr->bclink.deferred_head) - 1
                                 : n_ptr->bclink.last_sent);

                spin_lock_bh(&bc_lock);
                tipc_bearer_send(&bcbearer->bearer, buf, NULL);
                bcl->stats.sent_nacks++;
                spin_unlock_bh(&bc_lock);
                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.
 *
 * Only tipc_net_lock set.
 */
static void bclink_peek_nack(struct tipc_msg *msg)
{
        struct tipc_node *n_ptr = tipc_node_find(msg_destnode(msg));

        if (unlikely(!n_ptr))
                return;

        tipc_node_lock(n_ptr);

        if (n_ptr->bclink.supported &&
            (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_bclink_send_msg - broadcast a packet to all nodes in cluster
 */
int tipc_bclink_send_msg(struct sk_buff *buf)
{
        int res;

        spin_lock_bh(&bc_lock);

        if (!bclink->bcast_nodes.count) {
                res = msg_data_sz(buf_msg(buf));
                kfree_skb(buf);
                goto exit;
        }

        res = tipc_link_send_buf(bcl, buf);
        if (likely(res >= 0)) {
                bclink_set_last_sent();
                bcl->stats.queue_sz_counts++;
                bcl->stats.accu_queue_sz += bcl->out_queue_size;
        }
exit:
        spin_unlock_bh(&bc_lock);
        return res;
}

/**
 * bclink_accept_pkt - accept an incoming, in-sequence broadcast packet
 *
 * Called with both sending node's lock and bc_lock taken.
 */
static void bclink_accept_pkt(struct tipc_node *node, u32 seqno)
{
        bclink_update_last_sent(node, seqno);
        node->bclink.last_in = seqno;
        node->bclink.oos_state = 0;
        bcl->stats.recv_info++;

        /*
         * Unicast an ACK periodically, ensuring that
         * all nodes in the cluster don't ACK at the same time
         */

        if (((seqno - tipc_own_addr) % TIPC_MIN_LINK_WIN) == 0) {
                tipc_link_send_proto_msg(
                        node->active_links[node->addr & 1],
                        STATE_MSG, 0, 0, 0, 0, 0);
                bcl->stats.sent_acks++;
        }
}

/**
 * tipc_bclink_recv_pkt - receive a broadcast packet, and deliver upwards
 *
 * tipc_net_lock is read_locked, no other locks set
 */
void tipc_bclink_recv_pkt(struct sk_buff *buf)
{
        struct tipc_msg *msg = buf_msg(buf);
        struct tipc_node *node;
        u32 next_in;
        u32 seqno;
        int deferred;

        /* Screen out unwanted broadcast messages */

        if (msg_mc_netid(msg) != tipc_net_id)
                goto exit;

        node = tipc_node_find(msg_prevnode(msg));
        if (unlikely(!node))
                goto exit;

        tipc_node_lock(node);
        if (unlikely(!node->bclink.supported))
                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) == tipc_own_addr) {
                        tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
                        tipc_node_unlock(node);
                        spin_lock_bh(&bc_lock);
                        bcl->stats.recv_nacks++;
                        bclink->retransmit_to = node;
                        bclink_retransmit_pkt(msg_bcgap_after(msg),
                                              msg_bcgap_to(msg));
                        spin_unlock_bh(&bc_lock);
                } else {
                        tipc_node_unlock(node);
                        bclink_peek_nack(msg);
                }
                goto exit;
        }

        /* Handle in-sequence broadcast message */

        seqno = msg_seqno(msg);
        next_in = mod(node->bclink.last_in + 1);

        if (likely(seqno == next_in)) {
receive:
                /* Deliver message to destination */

                if (likely(msg_isdata(msg))) {
                        spin_lock_bh(&bc_lock);
                        bclink_accept_pkt(node, seqno);
                        spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        if (likely(msg_mcast(msg)))
                                tipc_port_recv_mcast(buf, NULL);
                        else
                                kfree_skb(buf);
                } else if (msg_user(msg) == MSG_BUNDLER) {
                        spin_lock_bh(&bc_lock);
                        bclink_accept_pkt(node, seqno);
                        bcl->stats.recv_bundles++;
                        bcl->stats.recv_bundled += msg_msgcnt(msg);
                        spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        tipc_link_recv_bundle(buf);
                } else if (msg_user(msg) == MSG_FRAGMENTER) {
                        int ret = tipc_link_recv_fragment(&node->bclink.defragm,
                                                      &buf, &msg);
                        if (ret < 0)
                                goto unlock;
                        spin_lock_bh(&bc_lock);
                        bclink_accept_pkt(node, seqno);
                        bcl->stats.recv_fragments++;
                        if (ret > 0)
                                bcl->stats.recv_fragmented++;
                        spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        tipc_net_route_msg(buf);
                } else if (msg_user(msg) == NAME_DISTRIBUTOR) {
                        spin_lock_bh(&bc_lock);
                        bclink_accept_pkt(node, seqno);
                        spin_unlock_bh(&bc_lock);
                        tipc_node_unlock(node);
                        tipc_named_recv(buf);
                } else {
                        spin_lock_bh(&bc_lock);
                        bclink_accept_pkt(node, seqno);
                        spin_unlock_bh(&bc_lock);
                        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 (!node->bclink.deferred_head) {
                        node->bclink.oos_state = 1;
                        goto unlock;
                }

                msg = buf_msg(node->bclink.deferred_head);
                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 = node->bclink.deferred_head;
                node->bclink.deferred_head = buf->next;
                node->bclink.deferred_size--;
                goto receive;
        }

        /* Handle out-of-sequence broadcast message */

        if (less(next_in, seqno)) {
                deferred = tipc_link_defer_pkt(&node->bclink.deferred_head,
                                               &node->bclink.deferred_tail,
                                               buf);
                node->bclink.deferred_size += deferred;
                bclink_update_last_sent(node, seqno);
                buf = NULL;
        } else
                deferred = 0;

        spin_lock_bh(&bc_lock);

        if (deferred)
                bcl->stats.deferred_recv++;
        else
                bcl->stats.duplicates++;

        spin_unlock_bh(&bc_lock);

unlock:
        tipc_node_unlock(node);
exit:
        kfree_skb(buf);
}

u32 tipc_bclink_acks_missing(struct tipc_node *n_ptr)
{
        return (n_ptr->bclink.supported &&
                (tipc_bclink_get_last_sent() != 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 sk_buff *buf,
                              struct tipc_bearer *unused1,
                              struct tipc_media_addr *unused2)
{
        int bp_index;

        /*
         * 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)))) {
                struct tipc_msg *msg;

                bcbuf_set_acks(buf, bclink->bcast_nodes.count);
                msg = buf_msg(buf);
                msg_set_non_seq(msg, 1);
                msg_set_mc_netid(msg, tipc_net_id);
                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;

                if (!p)
                        break;  /* no more bearers to try */

                tipc_nmap_diff(&bcbearer->remains, &p->nodes, &bcbearer->remains_new);
                if (bcbearer->remains_new.count == bcbearer->remains.count)
                        continue;       /* bearer pair doesn't add anything */

                if (p->blocked ||
                    p->media->send_msg(buf, p, &p->media->bcast_addr)) {
                        /* unable to send on primary bearer */
                        if (!s || s->blocked ||
                            s->media->send_msg(buf, s,
                                               &s->media->bcast_addr)) {
                                /* unable to send on either bearer */
                                continue;
                        }
                }

                if (s) {
                        bcbearer->bpairs[bp_index].primary = s;
                        bcbearer->bpairs[bp_index].secondary = p;
                }

                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(void)
{
        struct tipc_bcbearer_pair *bp_temp = bcbearer->bpairs_temp;
        struct tipc_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 tipc_bearer *b = &tipc_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_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++;
        }

        spin_unlock_bh(&bc_lock);
}


int tipc_bclink_stats(char *buf, const u32 buf_size)
{
        int ret;
        struct tipc_stats *s;

        if (!bcl)
                return 0;

        spin_lock_bh(&bc_lock);

        s = &bcl->stats;

        ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
                            "  Window:%u packets\n",
                            bcl->name, bcl->queue_limit[0]);
        ret += tipc_snprintf(buf + ret, buf_size - ret,
                             "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
                             s->recv_info, s->recv_fragments,
                             s->recv_fragmented, s->recv_bundles,
                             s->recv_bundled);
        ret += tipc_snprintf(buf + ret, buf_size - ret,
                             "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
                             s->sent_info, s->sent_fragments,
                             s->sent_fragmented, s->sent_bundles,
                             s->sent_bundled);
        ret += tipc_snprintf(buf + ret, buf_size - ret,
                             "  RX naks:%u defs:%u dups:%u\n",
                             s->recv_nacks, s->deferred_recv, s->duplicates);
        ret += tipc_snprintf(buf + ret, buf_size - ret,
                             "  TX naks:%u acks:%u dups:%u\n",
                             s->sent_nacks, s->sent_acks, s->retransmitted);
        ret += tipc_snprintf(buf + ret, buf_size - ret,
                             "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
                             s->bearer_congs, s->link_congs, s->max_queue_sz,
                             s->queue_sz_counts ?
                             (s->accu_queue_sz / s->queue_sz_counts) : 0);

        spin_unlock_bh(&bc_lock);
        return ret;
}

int tipc_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 0;
}

int tipc_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);
        tipc_link_set_queue_limits(bcl, limit);
        spin_unlock_bh(&bc_lock);
        return 0;
}

void tipc_bclink_init(void)
{
        INIT_LIST_HEAD(&bcbearer->bearer.cong_links);
        bcbearer->bearer.media = &bcbearer->media;
        bcbearer->media.send_msg = tipc_bcbearer_send;
        sprintf(bcbearer->media.name, "tipc-broadcast");

        INIT_LIST_HEAD(&bcl->waiting_ports);
        bcl->next_out_no = 1;
        spin_lock_init(&bclink->node.lock);
        bcl->owner = &bclink->node;
        bcl->max_pkt = MAX_PKT_DEFAULT_MCAST;
        tipc_link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT);
        bcl->b_ptr = &bcbearer->bearer;
        bcl->state = WORKING_WORKING;
        strlcpy(bcl->name, tipc_bclink_name, TIPC_MAX_LINK_NAME);
}

void tipc_bclink_stop(void)
{
        spin_lock_bh(&bc_lock);
        tipc_link_stop(bcl);
        spin_unlock_bh(&bc_lock);

        memset(bclink, 0, sizeof(*bclink));
        memset(bcbearer, 0, sizeof(*bcbearer));
}


/**
 * tipc_nmap_add - add a node to a node map
 */
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
 */
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++;
                        }
                }
        }
}

/**
 * tipc_port_list_add - add a port to a port list, ensuring no duplicates
 */
void tipc_port_list_add(struct tipc_port_list *pl_ptr, u32 port)
{
        struct tipc_port_list *item = pl_ptr;
        int i;
        int item_sz = PLSIZE;
        int cnt = pl_ptr->count;

        for (; ; cnt -= item_sz, item = item->next) {
                if (cnt < PLSIZE)
                        item_sz = cnt;
                for (i = 0; i < item_sz; i++)
                        if (item->ports[i] == port)
                                return;
                if (i < PLSIZE) {
                        item->ports[i] = port;
                        pl_ptr->count++;
                        return;
                }
                if (!item->next) {
                        item->next = kmalloc(sizeof(*item), GFP_ATOMIC);
                        if (!item->next) {
                                pr_warn("Incomplete multicast delivery, no memory\n");
                                return;
                        }
                        item->next->next = NULL;
                }
        }
}

/**
 * tipc_port_list_free - free dynamically created entries in port_list chain
 *
 */
void tipc_port_list_free(struct tipc_port_list *pl_ptr)
{
        struct tipc_port_list *item;
        struct tipc_port_list *next;

        for (item = pl_ptr->next; item; item = next) {
                next = item->next;
                kfree(item);
        }
}