bcast.c

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

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 {
    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;
}


struct tipc_node *tipc_bclink_retransmit_to(void)
{
    return bclink->retransmit_to;
}

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));
}

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);
}

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++;
    }
}

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;
}

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++;
    }
}

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));
}


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;
}

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));
}


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;
    }
}

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--;
    }
}

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++;
            }
        }
    }
}

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;
        }
    }
}

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);
    }
}