link.c

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/*
 * net/tipc/link.c: TIPC link code
 *
 * Copyright (c) 1996-2007, Ericsson AB
 * Copyright (c) 2004-2007, 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 "name_distr.h"
#include "discover.h"
#include "config.h"

/*
 * Error message prefixes
 */
static const char *link_co_err = "Link changeover error, ";
static const char *link_rst_msg = "Resetting link ";
static const char *link_unk_evt = "Unknown link event ";

/*
 * Out-of-range value for link session numbers
 */
#define INVALID_SESSION 0x10000

/*
 * Link state events:
 */
#define  STARTING_EVT    856384768  /* link processing trigger */
#define  TRAFFIC_MSG_EVT 560815u    /* rx'd ??? */
#define  TIMEOUT_EVT     560817u    /* link timer expired */

/*
 * The following two 'message types' is really just implementation
 * data conveniently stored in the message header.
 * They must not be considered part of the protocol
 */
#define OPEN_MSG   0
#define CLOSED_MSG 1

/*
 * State value stored in 'exp_msg_count'
 */
#define START_CHANGEOVER 100000u

struct tipc_link_name {
    u32 addr_local;
    char if_local[TIPC_MAX_IF_NAME];
    u32 addr_peer;
    char if_peer[TIPC_MAX_IF_NAME];
};

static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
                       struct sk_buff *buf);
static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf);
static int  link_recv_changeover_msg(struct tipc_link **l_ptr,
                     struct sk_buff **buf);
static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance);
static int  link_send_sections_long(struct tipc_port *sender,
                    struct iovec const *msg_sect,
                    u32 num_sect, unsigned int total_len,
                    u32 destnode);
static void link_check_defragm_bufs(struct tipc_link *l_ptr);
static void link_state_event(struct tipc_link *l_ptr, u32 event);
static void link_reset_statistics(struct tipc_link *l_ptr);
static void link_print(struct tipc_link *l_ptr, const char *str);
static void link_start(struct tipc_link *l_ptr);
static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf);

/*
 *  Simple link routines
 */
static unsigned int align(unsigned int i)
{
    return (i + 3) & ~3u;
}

static void link_init_max_pkt(struct tipc_link *l_ptr)
{
    u32 max_pkt;

    max_pkt = (l_ptr->b_ptr->mtu & ~3);
    if (max_pkt > MAX_MSG_SIZE)
        max_pkt = MAX_MSG_SIZE;

    l_ptr->max_pkt_target = max_pkt;
    if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
        l_ptr->max_pkt = l_ptr->max_pkt_target;
    else
        l_ptr->max_pkt = MAX_PKT_DEFAULT;

    l_ptr->max_pkt_probes = 0;
}

static u32 link_next_sent(struct tipc_link *l_ptr)
{
    if (l_ptr->next_out)
        return buf_seqno(l_ptr->next_out);
    return mod(l_ptr->next_out_no);
}

static u32 link_last_sent(struct tipc_link *l_ptr)
{
    return mod(link_next_sent(l_ptr) - 1);
}

/*
 *  Simple non-static link routines (i.e. referenced outside this file)
 */
int tipc_link_is_up(struct tipc_link *l_ptr)
{
    if (!l_ptr)
        return 0;
    return link_working_working(l_ptr) || link_working_unknown(l_ptr);
}

int tipc_link_is_active(struct tipc_link *l_ptr)
{
    return  (l_ptr->owner->active_links[0] == l_ptr) ||
        (l_ptr->owner->active_links[1] == l_ptr);
}

static int link_name_validate(const char *name,
                struct tipc_link_name *name_parts)
{
    char name_copy[TIPC_MAX_LINK_NAME];
    char *addr_local;
    char *if_local;
    char *addr_peer;
    char *if_peer;
    char dummy;
    u32 z_local, c_local, n_local;
    u32 z_peer, c_peer, n_peer;
    u32 if_local_len;
    u32 if_peer_len;

    /* copy link name & ensure length is OK */
    name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
    /* need above in case non-Posix strncpy() doesn't pad with nulls */
    strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
    if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
        return 0;

    /* ensure all component parts of link name are present */
    addr_local = name_copy;
    if_local = strchr(addr_local, ':');
    if (if_local == NULL)
        return 0;
    *(if_local++) = 0;
    addr_peer = strchr(if_local, '-');
    if (addr_peer == NULL)
        return 0;
    *(addr_peer++) = 0;
    if_local_len = addr_peer - if_local;
    if_peer = strchr(addr_peer, ':');
    if (if_peer == NULL)
        return 0;
    *(if_peer++) = 0;
    if_peer_len = strlen(if_peer) + 1;

    /* validate component parts of link name */
    if ((sscanf(addr_local, "%u.%u.%u%c",
            &z_local, &c_local, &n_local, &dummy) != 3) ||
        (sscanf(addr_peer, "%u.%u.%u%c",
            &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
        (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
        (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
        (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
        (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME))
        return 0;

    /* return link name components, if necessary */
    if (name_parts) {
        name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
        strcpy(name_parts->if_local, if_local);
        name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
        strcpy(name_parts->if_peer, if_peer);
    }
    return 1;
}

static void link_timeout(struct tipc_link *l_ptr)
{
    tipc_node_lock(l_ptr->owner);

    /* update counters used in statistical profiling of send traffic */
    l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
    l_ptr->stats.queue_sz_counts++;

    if (l_ptr->first_out) {
        struct tipc_msg *msg = buf_msg(l_ptr->first_out);
        u32 length = msg_size(msg);

        if ((msg_user(msg) == MSG_FRAGMENTER) &&
            (msg_type(msg) == FIRST_FRAGMENT)) {
            length = msg_size(msg_get_wrapped(msg));
        }
        if (length) {
            l_ptr->stats.msg_lengths_total += length;
            l_ptr->stats.msg_length_counts++;
            if (length <= 64)
                l_ptr->stats.msg_length_profile[0]++;
            else if (length <= 256)
                l_ptr->stats.msg_length_profile[1]++;
            else if (length <= 1024)
                l_ptr->stats.msg_length_profile[2]++;
            else if (length <= 4096)
                l_ptr->stats.msg_length_profile[3]++;
            else if (length <= 16384)
                l_ptr->stats.msg_length_profile[4]++;
            else if (length <= 32768)
                l_ptr->stats.msg_length_profile[5]++;
            else
                l_ptr->stats.msg_length_profile[6]++;
        }
    }

    /* do all other link processing performed on a periodic basis */
    link_check_defragm_bufs(l_ptr);

    link_state_event(l_ptr, TIMEOUT_EVT);

    if (l_ptr->next_out)
        tipc_link_push_queue(l_ptr);

    tipc_node_unlock(l_ptr->owner);
}

static void link_set_timer(struct tipc_link *l_ptr, u32 time)
{
    k_start_timer(&l_ptr->timer, time);
}

struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
                  struct tipc_bearer *b_ptr,
                  const struct tipc_media_addr *media_addr)
{
    struct tipc_link *l_ptr;
    struct tipc_msg *msg;
    char *if_name;
    char addr_string[16];
    u32 peer = n_ptr->addr;

    if (n_ptr->link_cnt >= 2) {
        tipc_addr_string_fill(addr_string, n_ptr->addr);
        pr_err("Attempt to establish third link to %s\n", addr_string);
        return NULL;
    }

    if (n_ptr->links[b_ptr->identity]) {
        tipc_addr_string_fill(addr_string, n_ptr->addr);
        pr_err("Attempt to establish second link on <%s> to %s\n",
               b_ptr->name, addr_string);
        return NULL;
    }

    l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
    if (!l_ptr) {
        pr_warn("Link creation failed, no memory\n");
        return NULL;
    }

    l_ptr->addr = peer;
    if_name = strchr(b_ptr->name, ':') + 1;
    sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:unknown",
        tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
        tipc_node(tipc_own_addr),
        if_name,
        tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
        /* note: peer i/f name is updated by reset/activate message */
    memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
    l_ptr->owner = n_ptr;
    l_ptr->checkpoint = 1;
    l_ptr->peer_session = INVALID_SESSION;
    l_ptr->b_ptr = b_ptr;
    link_set_supervision_props(l_ptr, b_ptr->tolerance);
    l_ptr->state = RESET_UNKNOWN;

    l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
    msg = l_ptr->pmsg;
    tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
    msg_set_size(msg, sizeof(l_ptr->proto_msg));
    msg_set_session(msg, (tipc_random & 0xffff));
    msg_set_bearer_id(msg, b_ptr->identity);
    strcpy((char *)msg_data(msg), if_name);

    l_ptr->priority = b_ptr->priority;
    tipc_link_set_queue_limits(l_ptr, b_ptr->window);

    link_init_max_pkt(l_ptr);

    l_ptr->next_out_no = 1;
    INIT_LIST_HEAD(&l_ptr->waiting_ports);

    link_reset_statistics(l_ptr);

    tipc_node_attach_link(n_ptr, l_ptr);

    k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
    list_add_tail(&l_ptr->link_list, &b_ptr->links);
    tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);

    return l_ptr;
}

void tipc_link_delete(struct tipc_link *l_ptr)
{
    if (!l_ptr) {
        pr_err("Attempt to delete non-existent link\n");
        return;
    }

    k_cancel_timer(&l_ptr->timer);

    tipc_node_lock(l_ptr->owner);
    tipc_link_reset(l_ptr);
    tipc_node_detach_link(l_ptr->owner, l_ptr);
    tipc_link_stop(l_ptr);
    list_del_init(&l_ptr->link_list);
    tipc_node_unlock(l_ptr->owner);
    k_term_timer(&l_ptr->timer);
    kfree(l_ptr);
}

static void link_start(struct tipc_link *l_ptr)
{
    tipc_node_lock(l_ptr->owner);
    link_state_event(l_ptr, STARTING_EVT);
    tipc_node_unlock(l_ptr->owner);
}

static int link_schedule_port(struct tipc_link *l_ptr, u32 origport, u32 sz)
{
    struct tipc_port *p_ptr;

    spin_lock_bh(&tipc_port_list_lock);
    p_ptr = tipc_port_lock(origport);
    if (p_ptr) {
        if (!p_ptr->wakeup)
            goto exit;
        if (!list_empty(&p_ptr->wait_list))
            goto exit;
        p_ptr->congested = 1;
        p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
        list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
        l_ptr->stats.link_congs++;
exit:
        tipc_port_unlock(p_ptr);
    }
    spin_unlock_bh(&tipc_port_list_lock);
    return -ELINKCONG;
}

void tipc_link_wakeup_ports(struct tipc_link *l_ptr, int all)
{
    struct tipc_port *p_ptr;
    struct tipc_port *temp_p_ptr;
    int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;

    if (all)
        win = 100000;
    if (win <= 0)
        return;
    if (!spin_trylock_bh(&tipc_port_list_lock))
        return;
    if (link_congested(l_ptr))
        goto exit;
    list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
                 wait_list) {
        if (win <= 0)
            break;
        list_del_init(&p_ptr->wait_list);
        spin_lock_bh(p_ptr->lock);
        p_ptr->congested = 0;
        p_ptr->wakeup(p_ptr);
        win -= p_ptr->waiting_pkts;
        spin_unlock_bh(p_ptr->lock);
    }

exit:
    spin_unlock_bh(&tipc_port_list_lock);
}

static void link_release_outqueue(struct tipc_link *l_ptr)
{
    struct sk_buff *buf = l_ptr->first_out;
    struct sk_buff *next;

    while (buf) {
        next = buf->next;
        kfree_skb(buf);
        buf = next;
    }
    l_ptr->first_out = NULL;
    l_ptr->out_queue_size = 0;
}

void tipc_link_reset_fragments(struct tipc_link *l_ptr)
{
    struct sk_buff *buf = l_ptr->defragm_buf;
    struct sk_buff *next;

    while (buf) {
        next = buf->next;
        kfree_skb(buf);
        buf = next;
    }
    l_ptr->defragm_buf = NULL;
}

void tipc_link_stop(struct tipc_link *l_ptr)
{
    struct sk_buff *buf;
    struct sk_buff *next;

    buf = l_ptr->oldest_deferred_in;
    while (buf) {
        next = buf->next;
        kfree_skb(buf);
        buf = next;
    }

    buf = l_ptr->first_out;
    while (buf) {
        next = buf->next;
        kfree_skb(buf);
        buf = next;
    }

    tipc_link_reset_fragments(l_ptr);

    kfree_skb(l_ptr->proto_msg_queue);
    l_ptr->proto_msg_queue = NULL;
}

void tipc_link_reset(struct tipc_link *l_ptr)
{
    struct sk_buff *buf;
    u32 prev_state = l_ptr->state;
    u32 checkpoint = l_ptr->next_in_no;
    int was_active_link = tipc_link_is_active(l_ptr);

    msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));

    /* Link is down, accept any session */
    l_ptr->peer_session = INVALID_SESSION;

    /* Prepare for max packet size negotiation */
    link_init_max_pkt(l_ptr);

    l_ptr->state = RESET_UNKNOWN;

    if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
        return;

    tipc_node_link_down(l_ptr->owner, l_ptr);
    tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);

    if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
        l_ptr->owner->permit_changeover) {
        l_ptr->reset_checkpoint = checkpoint;
        l_ptr->exp_msg_count = START_CHANGEOVER;
    }

    /* Clean up all queues: */
    link_release_outqueue(l_ptr);
    kfree_skb(l_ptr->proto_msg_queue);
    l_ptr->proto_msg_queue = NULL;
    buf = l_ptr->oldest_deferred_in;
    while (buf) {
        struct sk_buff *next = buf->next;
        kfree_skb(buf);
        buf = next;
    }
    if (!list_empty(&l_ptr->waiting_ports))
        tipc_link_wakeup_ports(l_ptr, 1);

    l_ptr->retransm_queue_head = 0;
    l_ptr->retransm_queue_size = 0;
    l_ptr->last_out = NULL;
    l_ptr->first_out = NULL;
    l_ptr->next_out = NULL;
    l_ptr->unacked_window = 0;
    l_ptr->checkpoint = 1;
    l_ptr->next_out_no = 1;
    l_ptr->deferred_inqueue_sz = 0;
    l_ptr->oldest_deferred_in = NULL;
    l_ptr->newest_deferred_in = NULL;
    l_ptr->fsm_msg_cnt = 0;
    l_ptr->stale_count = 0;
    link_reset_statistics(l_ptr);
}


static void link_activate(struct tipc_link *l_ptr)
{
    l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
    tipc_node_link_up(l_ptr->owner, l_ptr);
    tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
}

static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
{
    struct tipc_link *other;
    u32 cont_intv = l_ptr->continuity_interval;

    if (!l_ptr->started && (event != STARTING_EVT))
        return;     /* Not yet. */

    if (link_blocked(l_ptr)) {
        if (event == TIMEOUT_EVT)
            link_set_timer(l_ptr, cont_intv);
        return;   /* Changeover going on */
    }

    switch (l_ptr->state) {
    case WORKING_WORKING:
        switch (event) {
        case TRAFFIC_MSG_EVT:
        case ACTIVATE_MSG:
            break;
        case TIMEOUT_EVT:
            if (l_ptr->next_in_no != l_ptr->checkpoint) {
                l_ptr->checkpoint = l_ptr->next_in_no;
                if (tipc_bclink_acks_missing(l_ptr->owner)) {
                    tipc_link_send_proto_msg(l_ptr, STATE_MSG,
                                 0, 0, 0, 0, 0);
                    l_ptr->fsm_msg_cnt++;
                } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
                    tipc_link_send_proto_msg(l_ptr, STATE_MSG,
                                 1, 0, 0, 0, 0);
                    l_ptr->fsm_msg_cnt++;
                }
                link_set_timer(l_ptr, cont_intv);
                break;
            }
            l_ptr->state = WORKING_UNKNOWN;
            l_ptr->fsm_msg_cnt = 0;
            tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv / 4);
            break;
        case RESET_MSG:
            pr_info("%s<%s>, requested by peer\n", link_rst_msg,
                l_ptr->name);
            tipc_link_reset(l_ptr);
            l_ptr->state = RESET_RESET;
            l_ptr->fsm_msg_cnt = 0;
            tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv);
            break;
        default:
            pr_err("%s%u in WW state\n", link_unk_evt, event);
        }
        break;
    case WORKING_UNKNOWN:
        switch (event) {
        case TRAFFIC_MSG_EVT:
        case ACTIVATE_MSG:
            l_ptr->state = WORKING_WORKING;
            l_ptr->fsm_msg_cnt = 0;
            link_set_timer(l_ptr, cont_intv);
            break;
        case RESET_MSG:
            pr_info("%s<%s>, requested by peer while probing\n",
                link_rst_msg, l_ptr->name);
            tipc_link_reset(l_ptr);
            l_ptr->state = RESET_RESET;
            l_ptr->fsm_msg_cnt = 0;
            tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv);
            break;
        case TIMEOUT_EVT:
            if (l_ptr->next_in_no != l_ptr->checkpoint) {
                l_ptr->state = WORKING_WORKING;
                l_ptr->fsm_msg_cnt = 0;
                l_ptr->checkpoint = l_ptr->next_in_no;
                if (tipc_bclink_acks_missing(l_ptr->owner)) {
                    tipc_link_send_proto_msg(l_ptr, STATE_MSG,
                                 0, 0, 0, 0, 0);
                    l_ptr->fsm_msg_cnt++;
                }
                link_set_timer(l_ptr, cont_intv);
            } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
                tipc_link_send_proto_msg(l_ptr, STATE_MSG,
                             1, 0, 0, 0, 0);
                l_ptr->fsm_msg_cnt++;
                link_set_timer(l_ptr, cont_intv / 4);
            } else {    /* Link has failed */
                pr_warn("%s<%s>, peer not responding\n",
                    link_rst_msg, l_ptr->name);
                tipc_link_reset(l_ptr);
                l_ptr->state = RESET_UNKNOWN;
                l_ptr->fsm_msg_cnt = 0;
                tipc_link_send_proto_msg(l_ptr, RESET_MSG,
                             0, 0, 0, 0, 0);
                l_ptr->fsm_msg_cnt++;
                link_set_timer(l_ptr, cont_intv);
            }
            break;
        default:
            pr_err("%s%u in WU state\n", link_unk_evt, event);
        }
        break;
    case RESET_UNKNOWN:
        switch (event) {
        case TRAFFIC_MSG_EVT:
            break;
        case ACTIVATE_MSG:
            other = l_ptr->owner->active_links[0];
            if (other && link_working_unknown(other))
                break;
            l_ptr->state = WORKING_WORKING;
            l_ptr->fsm_msg_cnt = 0;
            link_activate(l_ptr);
            tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv);
            break;
        case RESET_MSG:
            l_ptr->state = RESET_RESET;
            l_ptr->fsm_msg_cnt = 0;
            tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv);
            break;
        case STARTING_EVT:
            l_ptr->started = 1;
            /* fall through */
        case TIMEOUT_EVT:
            tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv);
            break;
        default:
            pr_err("%s%u in RU state\n", link_unk_evt, event);
        }
        break;
    case RESET_RESET:
        switch (event) {
        case TRAFFIC_MSG_EVT:
        case ACTIVATE_MSG:
            other = l_ptr->owner->active_links[0];
            if (other && link_working_unknown(other))
                break;
            l_ptr->state = WORKING_WORKING;
            l_ptr->fsm_msg_cnt = 0;
            link_activate(l_ptr);
            tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv);
            break;
        case RESET_MSG:
            break;
        case TIMEOUT_EVT:
            tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
            l_ptr->fsm_msg_cnt++;
            link_set_timer(l_ptr, cont_intv);
            break;
        default:
            pr_err("%s%u in RR state\n", link_unk_evt, event);
        }
        break;
    default:
        pr_err("Unknown link state %u/%u\n", l_ptr->state, event);
    }
}

/*
 * link_bundle_buf(): Append contents of a buffer to
 * the tail of an existing one.
 */
static int link_bundle_buf(struct tipc_link *l_ptr,
               struct sk_buff *bundler,
               struct sk_buff *buf)
{
    struct tipc_msg *bundler_msg = buf_msg(bundler);
    struct tipc_msg *msg = buf_msg(buf);
    u32 size = msg_size(msg);
    u32 bundle_size = msg_size(bundler_msg);
    u32 to_pos = align(bundle_size);
    u32 pad = to_pos - bundle_size;

    if (msg_user(bundler_msg) != MSG_BUNDLER)
        return 0;
    if (msg_type(bundler_msg) != OPEN_MSG)
        return 0;
    if (skb_tailroom(bundler) < (pad + size))
        return 0;
    if (l_ptr->max_pkt < (to_pos + size))
        return 0;

    skb_put(bundler, pad + size);
    skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
    msg_set_size(bundler_msg, to_pos + size);
    msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
    kfree_skb(buf);
    l_ptr->stats.sent_bundled++;
    return 1;
}

static void link_add_to_outqueue(struct tipc_link *l_ptr,
                 struct sk_buff *buf,
                 struct tipc_msg *msg)
{
    u32 ack = mod(l_ptr->next_in_no - 1);
    u32 seqno = mod(l_ptr->next_out_no++);

    msg_set_word(msg, 2, ((ack << 16) | seqno));
    msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
    buf->next = NULL;
    if (l_ptr->first_out) {
        l_ptr->last_out->next = buf;
        l_ptr->last_out = buf;
    } else
        l_ptr->first_out = l_ptr->last_out = buf;

    l_ptr->out_queue_size++;
    if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
        l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
}

static void link_add_chain_to_outqueue(struct tipc_link *l_ptr,
                       struct sk_buff *buf_chain,
                       u32 long_msgno)
{
    struct sk_buff *buf;
    struct tipc_msg *msg;

    if (!l_ptr->next_out)
        l_ptr->next_out = buf_chain;
    while (buf_chain) {
        buf = buf_chain;
        buf_chain = buf_chain->next;

        msg = buf_msg(buf);
        msg_set_long_msgno(msg, long_msgno);
        link_add_to_outqueue(l_ptr, buf, msg);
    }
}

/*
 * tipc_link_send_buf() is the 'full path' for messages, called from
 * inside TIPC when the 'fast path' in tipc_send_buf
 * has failed, and from link_send()
 */
int tipc_link_send_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
{
    struct tipc_msg *msg = buf_msg(buf);
    u32 size = msg_size(msg);
    u32 dsz = msg_data_sz(msg);
    u32 queue_size = l_ptr->out_queue_size;
    u32 imp = tipc_msg_tot_importance(msg);
    u32 queue_limit = l_ptr->queue_limit[imp];
    u32 max_packet = l_ptr->max_pkt;

    /* Match msg importance against queue limits: */
    if (unlikely(queue_size >= queue_limit)) {
        if (imp <= TIPC_CRITICAL_IMPORTANCE) {
            link_schedule_port(l_ptr, msg_origport(msg), size);
            kfree_skb(buf);
            return -ELINKCONG;
        }
        kfree_skb(buf);
        if (imp > CONN_MANAGER) {
            pr_warn("%s<%s>, send queue full", link_rst_msg,
                l_ptr->name);
            tipc_link_reset(l_ptr);
        }
        return dsz;
    }

    /* Fragmentation needed ? */
    if (size > max_packet)
        return link_send_long_buf(l_ptr, buf);

    /* Packet can be queued or sent. */
    if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
           !link_congested(l_ptr))) {
        link_add_to_outqueue(l_ptr, buf, msg);

        if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
            l_ptr->unacked_window = 0;
        } else {
            tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
            l_ptr->stats.bearer_congs++;
            l_ptr->next_out = buf;
        }
        return dsz;
    }
    /* Congestion: can message be bundled ? */
    if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
        (msg_user(msg) != MSG_FRAGMENTER)) {

        /* Try adding message to an existing bundle */
        if (l_ptr->next_out &&
            link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
            tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
            return dsz;
        }

        /* Try creating a new bundle */
        if (size <= max_packet * 2 / 3) {
            struct sk_buff *bundler = tipc_buf_acquire(max_packet);
            struct tipc_msg bundler_hdr;

            if (bundler) {
                tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
                     INT_H_SIZE, l_ptr->addr);
                skb_copy_to_linear_data(bundler, &bundler_hdr,
                            INT_H_SIZE);
                skb_trim(bundler, INT_H_SIZE);
                link_bundle_buf(l_ptr, bundler, buf);
                buf = bundler;
                msg = buf_msg(buf);
                l_ptr->stats.sent_bundles++;
            }
        }
    }
    if (!l_ptr->next_out)
        l_ptr->next_out = buf;
    link_add_to_outqueue(l_ptr, buf, msg);
    tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
    return dsz;
}

/*
 * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
 * not been selected yet, and the the owner node is not locked
 * Called by TIPC internal users, e.g. the name distributor
 */
int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
{
    struct tipc_link *l_ptr;
    struct tipc_node *n_ptr;
    int res = -ELINKCONG;

    read_lock_bh(&tipc_net_lock);
    n_ptr = tipc_node_find(dest);
    if (n_ptr) {
        tipc_node_lock(n_ptr);
        l_ptr = n_ptr->active_links[selector & 1];
        if (l_ptr)
            res = tipc_link_send_buf(l_ptr, buf);
        else
            kfree_skb(buf);
        tipc_node_unlock(n_ptr);
    } else {
        kfree_skb(buf);
    }
    read_unlock_bh(&tipc_net_lock);
    return res;
}

void tipc_link_send_names(struct list_head *message_list, u32 dest)
{
    struct tipc_node *n_ptr;
    struct tipc_link *l_ptr;
    struct sk_buff *buf;
    struct sk_buff *temp_buf;

    if (list_empty(message_list))
        return;

    read_lock_bh(&tipc_net_lock);
    n_ptr = tipc_node_find(dest);
    if (n_ptr) {
        tipc_node_lock(n_ptr);
        l_ptr = n_ptr->active_links[0];
        if (l_ptr) {
            /* convert circular list to linear list */
            ((struct sk_buff *)message_list->prev)->next = NULL;
            link_add_chain_to_outqueue(l_ptr,
                (struct sk_buff *)message_list->next, 0);
            tipc_link_push_queue(l_ptr);
            INIT_LIST_HEAD(message_list);
        }
        tipc_node_unlock(n_ptr);
    }
    read_unlock_bh(&tipc_net_lock);

    /* discard the messages if they couldn't be sent */
    list_for_each_safe(buf, temp_buf, ((struct sk_buff *)message_list)) {
        list_del((struct list_head *)buf);
        kfree_skb(buf);
    }
}

/*
 * link_send_buf_fast: Entry for data messages where the
 * destination link is known and the header is complete,
 * inclusive total message length. Very time critical.
 * Link is locked. Returns user data length.
 */
static int link_send_buf_fast(struct tipc_link *l_ptr, struct sk_buff *buf,
                  u32 *used_max_pkt)
{
    struct tipc_msg *msg = buf_msg(buf);
    int res = msg_data_sz(msg);

    if (likely(!link_congested(l_ptr))) {
        if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
            if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
                link_add_to_outqueue(l_ptr, buf, msg);
                if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
                                &l_ptr->media_addr))) {
                    l_ptr->unacked_window = 0;
                    return res;
                }
                tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
                l_ptr->stats.bearer_congs++;
                l_ptr->next_out = buf;
                return res;
            }
        } else
            *used_max_pkt = l_ptr->max_pkt;
    }
    return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
}

/*
 * tipc_send_buf_fast: Entry for data messages where the
 * destination node is known and the header is complete,
 * inclusive total message length.
 * Returns user data length.
 */
int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
{
    struct tipc_link *l_ptr;
    struct tipc_node *n_ptr;
    int res;
    u32 selector = msg_origport(buf_msg(buf)) & 1;
    u32 dummy;

    read_lock_bh(&tipc_net_lock);
    n_ptr = tipc_node_find(destnode);
    if (likely(n_ptr)) {
        tipc_node_lock(n_ptr);
        l_ptr = n_ptr->active_links[selector];
        if (likely(l_ptr)) {
            res = link_send_buf_fast(l_ptr, buf, &dummy);
            tipc_node_unlock(n_ptr);
            read_unlock_bh(&tipc_net_lock);
            return res;
        }
        tipc_node_unlock(n_ptr);
    }
    read_unlock_bh(&tipc_net_lock);
    res = msg_data_sz(buf_msg(buf));
    tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
    return res;
}


/*
 * tipc_link_send_sections_fast: Entry for messages where the
 * destination processor is known and the header is complete,
 * except for total message length.
 * Returns user data length or errno.
 */
int tipc_link_send_sections_fast(struct tipc_port *sender,
                 struct iovec const *msg_sect,
                 const u32 num_sect,
                 unsigned int total_len,
                 u32 destaddr)
{
    struct tipc_msg *hdr = &sender->phdr;
    struct tipc_link *l_ptr;
    struct sk_buff *buf;
    struct tipc_node *node;
    int res;
    u32 selector = msg_origport(hdr) & 1;

again:
    /*
     * Try building message using port's max_pkt hint.
     * (Must not hold any locks while building message.)
     */
    res = tipc_msg_build(hdr, msg_sect, num_sect, total_len,
                 sender->max_pkt, !sender->user_port, &buf);

    read_lock_bh(&tipc_net_lock);
    node = tipc_node_find(destaddr);
    if (likely(node)) {
        tipc_node_lock(node);
        l_ptr = node->active_links[selector];
        if (likely(l_ptr)) {
            if (likely(buf)) {
                res = link_send_buf_fast(l_ptr, buf,
                             &sender->max_pkt);
exit:
                tipc_node_unlock(node);
                read_unlock_bh(&tipc_net_lock);
                return res;
            }

            /* Exit if build request was invalid */
            if (unlikely(res < 0))
                goto exit;

            /* Exit if link (or bearer) is congested */
            if (link_congested(l_ptr) ||
                !list_empty(&l_ptr->b_ptr->cong_links)) {
                res = link_schedule_port(l_ptr,
                             sender->ref, res);
                goto exit;
            }

            /*
             * Message size exceeds max_pkt hint; update hint,
             * then re-try fast path or fragment the message
             */
            sender->max_pkt = l_ptr->max_pkt;
            tipc_node_unlock(node);
            read_unlock_bh(&tipc_net_lock);


            if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
                goto again;

            return link_send_sections_long(sender, msg_sect,
                               num_sect, total_len,
                               destaddr);
        }
        tipc_node_unlock(node);
    }
    read_unlock_bh(&tipc_net_lock);

    /* Couldn't find a link to the destination node */
    if (buf)
        return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
    if (res >= 0)
        return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
                         total_len, TIPC_ERR_NO_NODE);
    return res;
}

/*
 * link_send_sections_long(): Entry for long messages where the
 * destination node is known and the header is complete,
 * inclusive total message length.
 * Link and bearer congestion status have been checked to be ok,
 * and are ignored if they change.
 *
 * Note that fragments do not use the full link MTU so that they won't have
 * to undergo refragmentation if link changeover causes them to be sent
 * over another link with an additional tunnel header added as prefix.
 * (Refragmentation will still occur if the other link has a smaller MTU.)
 *
 * Returns user data length or errno.
 */
static int link_send_sections_long(struct tipc_port *sender,
                   struct iovec const *msg_sect,
                   u32 num_sect,
                   unsigned int total_len,
                   u32 destaddr)
{
    struct tipc_link *l_ptr;
    struct tipc_node *node;
    struct tipc_msg *hdr = &sender->phdr;
    u32 dsz = total_len;
    u32 max_pkt, fragm_sz, rest;
    struct tipc_msg fragm_hdr;
    struct sk_buff *buf, *buf_chain, *prev;
    u32 fragm_crs, fragm_rest, hsz, sect_rest;
    const unchar *sect_crs;
    int curr_sect;
    u32 fragm_no;

again:
    fragm_no = 1;
    max_pkt = sender->max_pkt - INT_H_SIZE;
        /* leave room for tunnel header in case of link changeover */
    fragm_sz = max_pkt - INT_H_SIZE;
        /* leave room for fragmentation header in each fragment */
    rest = dsz;
    fragm_crs = 0;
    fragm_rest = 0;
    sect_rest = 0;
    sect_crs = NULL;
    curr_sect = -1;

    /* Prepare reusable fragment header */
    tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
         INT_H_SIZE, msg_destnode(hdr));
    msg_set_size(&fragm_hdr, max_pkt);
    msg_set_fragm_no(&fragm_hdr, 1);

    /* Prepare header of first fragment */
    buf_chain = buf = tipc_buf_acquire(max_pkt);
    if (!buf)
        return -ENOMEM;
    buf->next = NULL;
    skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
    hsz = msg_hdr_sz(hdr);
    skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);

    /* Chop up message */
    fragm_crs = INT_H_SIZE + hsz;
    fragm_rest = fragm_sz - hsz;

    do {        /* For all sections */
        u32 sz;

        if (!sect_rest) {
            sect_rest = msg_sect[++curr_sect].iov_len;
            sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
        }

        if (sect_rest < fragm_rest)
            sz = sect_rest;
        else
            sz = fragm_rest;

        if (likely(!sender->user_port)) {
            if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
error:
                for (; buf_chain; buf_chain = buf) {
                    buf = buf_chain->next;
                    kfree_skb(buf_chain);
                }
                return -EFAULT;
            }
        } else
            skb_copy_to_linear_data_offset(buf, fragm_crs,
                               sect_crs, sz);
        sect_crs += sz;
        sect_rest -= sz;
        fragm_crs += sz;
        fragm_rest -= sz;
        rest -= sz;

        if (!fragm_rest && rest) {

            /* Initiate new fragment: */
            if (rest <= fragm_sz) {
                fragm_sz = rest;
                msg_set_type(&fragm_hdr, LAST_FRAGMENT);
            } else {
                msg_set_type(&fragm_hdr, FRAGMENT);
            }
            msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
            msg_set_fragm_no(&fragm_hdr, ++fragm_no);
            prev = buf;
            buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
            if (!buf)
                goto error;

            buf->next = NULL;
            prev->next = buf;
            skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
            fragm_crs = INT_H_SIZE;
            fragm_rest = fragm_sz;
        }
    } while (rest > 0);

    /*
     * Now we have a buffer chain. Select a link and check
     * that packet size is still OK
     */
    node = tipc_node_find(destaddr);
    if (likely(node)) {
        tipc_node_lock(node);
        l_ptr = node->active_links[sender->ref & 1];
        if (!l_ptr) {
            tipc_node_unlock(node);
            goto reject;
        }
        if (l_ptr->max_pkt < max_pkt) {
            sender->max_pkt = l_ptr->max_pkt;
            tipc_node_unlock(node);
            for (; buf_chain; buf_chain = buf) {
                buf = buf_chain->next;
                kfree_skb(buf_chain);
            }
            goto again;
        }
    } else {
reject:
        for (; buf_chain; buf_chain = buf) {
            buf = buf_chain->next;
            kfree_skb(buf_chain);
        }
        return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
                         total_len, TIPC_ERR_NO_NODE);
    }

    /* Append chain of fragments to send queue & send them */
    l_ptr->long_msg_seq_no++;
    link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
    l_ptr->stats.sent_fragments += fragm_no;
    l_ptr->stats.sent_fragmented++;
    tipc_link_push_queue(l_ptr);
    tipc_node_unlock(node);
    return dsz;
}

/*
 * tipc_link_push_packet: Push one unsent packet to the media
 */
u32 tipc_link_push_packet(struct tipc_link *l_ptr)
{
    struct sk_buff *buf = l_ptr->first_out;
    u32 r_q_size = l_ptr->retransm_queue_size;
    u32 r_q_head = l_ptr->retransm_queue_head;

    /* Step to position where retransmission failed, if any,    */
    /* consider that buffers may have been released in meantime */
    if (r_q_size && buf) {
        u32 last = lesser(mod(r_q_head + r_q_size),
                  link_last_sent(l_ptr));
        u32 first = buf_seqno(buf);

        while (buf && less(first, r_q_head)) {
            first = mod(first + 1);
            buf = buf->next;
        }
        l_ptr->retransm_queue_head = r_q_head = first;
        l_ptr->retransm_queue_size = r_q_size = mod(last - first);
    }

    /* Continue retransmission now, if there is anything: */
    if (r_q_size && buf) {
        msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
        msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
        if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
            l_ptr->retransm_queue_head = mod(++r_q_head);
            l_ptr->retransm_queue_size = --r_q_size;
            l_ptr->stats.retransmitted++;
            return 0;
        } else {
            l_ptr->stats.bearer_congs++;
            return PUSH_FAILED;
        }
    }

    /* Send deferred protocol message, if any: */
    buf = l_ptr->proto_msg_queue;
    if (buf) {
        msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
        msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
        if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
            l_ptr->unacked_window = 0;
            kfree_skb(buf);
            l_ptr->proto_msg_queue = NULL;
            return 0;
        } else {
            l_ptr->stats.bearer_congs++;
            return PUSH_FAILED;
        }
    }

    /* Send one deferred data message, if send window not full: */
    buf = l_ptr->next_out;
    if (buf) {
        struct tipc_msg *msg = buf_msg(buf);
        u32 next = msg_seqno(msg);
        u32 first = buf_seqno(l_ptr->first_out);

        if (mod(next - first) < l_ptr->queue_limit[0]) {
            msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
            msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
            if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
                if (msg_user(msg) == MSG_BUNDLER)
                    msg_set_type(msg, CLOSED_MSG);
                l_ptr->next_out = buf->next;
                return 0;
            } else {
                l_ptr->stats.bearer_congs++;
                return PUSH_FAILED;
            }
        }
    }
    return PUSH_FINISHED;
}

/*
 * push_queue(): push out the unsent messages of a link where
 *               congestion has abated. Node is locked
 */
void tipc_link_push_queue(struct tipc_link *l_ptr)
{
    u32 res;

    if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
        return;

    do {
        res = tipc_link_push_packet(l_ptr);
    } while (!res);

    if (res == PUSH_FAILED)
        tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
}

static void link_reset_all(unsigned long addr)
{
    struct tipc_node *n_ptr;
    char addr_string[16];
    u32 i;

    read_lock_bh(&tipc_net_lock);
    n_ptr = tipc_node_find((u32)addr);
    if (!n_ptr) {
        read_unlock_bh(&tipc_net_lock);
        return; /* node no longer exists */
    }

    tipc_node_lock(n_ptr);

    pr_warn("Resetting all links to %s\n",
        tipc_addr_string_fill(addr_string, n_ptr->addr));

    for (i = 0; i < MAX_BEARERS; i++) {
        if (n_ptr->links[i]) {
            link_print(n_ptr->links[i], "Resetting link\n");
            tipc_link_reset(n_ptr->links[i]);
        }
    }

    tipc_node_unlock(n_ptr);
    read_unlock_bh(&tipc_net_lock);
}

static void link_retransmit_failure(struct tipc_link *l_ptr,
                    struct sk_buff *buf)
{
    struct tipc_msg *msg = buf_msg(buf);

    pr_warn("Retransmission failure on link <%s>\n", l_ptr->name);

    if (l_ptr->addr) {
        /* Handle failure on standard link */
        link_print(l_ptr, "Resetting link\n");
        tipc_link_reset(l_ptr);

    } else {
        /* Handle failure on broadcast link */
        struct tipc_node *n_ptr;
        char addr_string[16];

        pr_info("Msg seq number: %u,  ", msg_seqno(msg));
        pr_cont("Outstanding acks: %lu\n",
            (unsigned long) TIPC_SKB_CB(buf)->handle);

        n_ptr = tipc_bclink_retransmit_to();
        tipc_node_lock(n_ptr);

        tipc_addr_string_fill(addr_string, n_ptr->addr);
        pr_info("Broadcast link info for %s\n", addr_string);
        pr_info("Supportable: %d,  Supported: %d,  Acked: %u\n",
            n_ptr->bclink.supportable,
            n_ptr->bclink.supported,
            n_ptr->bclink.acked);
        pr_info("Last in: %u,  Oos state: %u,  Last sent: %u\n",
            n_ptr->bclink.last_in,
            n_ptr->bclink.oos_state,
            n_ptr->bclink.last_sent);

        tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);

        tipc_node_unlock(n_ptr);

        l_ptr->stale_count = 0;
    }
}

void tipc_link_retransmit(struct tipc_link *l_ptr, struct sk_buff *buf,
              u32 retransmits)
{
    struct tipc_msg *msg;

    if (!buf)
        return;

    msg = buf_msg(buf);

    if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
        if (l_ptr->retransm_queue_size == 0) {
            l_ptr->retransm_queue_head = msg_seqno(msg);
            l_ptr->retransm_queue_size = retransmits;
        } else {
            pr_err("Unexpected retransmit on link %s (qsize=%d)\n",
                   l_ptr->name, l_ptr->retransm_queue_size);
        }
        return;
    } else {
        /* Detect repeated retransmit failures on uncongested bearer */
        if (l_ptr->last_retransmitted == msg_seqno(msg)) {
            if (++l_ptr->stale_count > 100) {
                link_retransmit_failure(l_ptr, buf);
                return;
            }
        } else {
            l_ptr->last_retransmitted = msg_seqno(msg);
            l_ptr->stale_count = 1;
        }
    }

    while (retransmits && (buf != l_ptr->next_out) && buf) {
        msg = buf_msg(buf);
        msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
        msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
        if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
            buf = buf->next;
            retransmits--;
            l_ptr->stats.retransmitted++;
        } else {
            tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
            l_ptr->stats.bearer_congs++;
            l_ptr->retransm_queue_head = buf_seqno(buf);
            l_ptr->retransm_queue_size = retransmits;
            return;
        }
    }

    l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
}

static struct sk_buff *link_insert_deferred_queue(struct tipc_link *l_ptr,
                          struct sk_buff *buf)
{
    u32 seq_no;

    if (l_ptr->oldest_deferred_in == NULL)
        return buf;

    seq_no = buf_seqno(l_ptr->oldest_deferred_in);
    if (seq_no == mod(l_ptr->next_in_no)) {
        l_ptr->newest_deferred_in->next = buf;
        buf = l_ptr->oldest_deferred_in;
        l_ptr->oldest_deferred_in = NULL;
        l_ptr->deferred_inqueue_sz = 0;
    }
    return buf;
}

static int link_recv_buf_validate(struct sk_buff *buf)
{
    static u32 min_data_hdr_size[8] = {
        SHORT_H_SIZE, MCAST_H_SIZE, NAMED_H_SIZE, BASIC_H_SIZE,
        MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
        };

    struct tipc_msg *msg;
    u32 tipc_hdr[2];
    u32 size;
    u32 hdr_size;
    u32 min_hdr_size;

    if (unlikely(buf->len < MIN_H_SIZE))
        return 0;

    msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
    if (msg == NULL)
        return 0;

    if (unlikely(msg_version(msg) != TIPC_VERSION))
        return 0;

    size = msg_size(msg);
    hdr_size = msg_hdr_sz(msg);
    min_hdr_size = msg_isdata(msg) ?
        min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;

    if (unlikely((hdr_size < min_hdr_size) ||
             (size < hdr_size) ||
             (buf->len < size) ||
             (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
        return 0;

    return pskb_may_pull(buf, hdr_size);
}

void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
{
    read_lock_bh(&tipc_net_lock);
    while (head) {
        struct tipc_node *n_ptr;
        struct tipc_link *l_ptr;
        struct sk_buff *crs;
        struct sk_buff *buf = head;
        struct tipc_msg *msg;
        u32 seq_no;
        u32 ackd;
        u32 released = 0;
        int type;

        head = head->next;

        /* Ensure bearer is still enabled */
        if (unlikely(!b_ptr->active))
            goto cont;

        /* Ensure message is well-formed */
        if (unlikely(!link_recv_buf_validate(buf)))
            goto cont;

        /* Ensure message data is a single contiguous unit */
        if (unlikely(skb_linearize(buf)))
            goto cont;

        /* Handle arrival of a non-unicast link message */
        msg = buf_msg(buf);

        if (unlikely(msg_non_seq(msg))) {
            if (msg_user(msg) ==  LINK_CONFIG)
                tipc_disc_recv_msg(buf, b_ptr);
            else
                tipc_bclink_recv_pkt(buf);
            continue;
        }

        /* Discard unicast link messages destined for another node */
        if (unlikely(!msg_short(msg) &&
                 (msg_destnode(msg) != tipc_own_addr)))
            goto cont;

        /* Locate neighboring node that sent message */
        n_ptr = tipc_node_find(msg_prevnode(msg));
        if (unlikely(!n_ptr))
            goto cont;
        tipc_node_lock(n_ptr);

        /* Locate unicast link endpoint that should handle message */
        l_ptr = n_ptr->links[b_ptr->identity];
        if (unlikely(!l_ptr)) {
            tipc_node_unlock(n_ptr);
            goto cont;
        }

        /* Verify that communication with node is currently allowed */
        if ((n_ptr->block_setup & WAIT_PEER_DOWN) &&
            msg_user(msg) == LINK_PROTOCOL &&
            (msg_type(msg) == RESET_MSG ||
                    msg_type(msg) == ACTIVATE_MSG) &&
            !msg_redundant_link(msg))
            n_ptr->block_setup &= ~WAIT_PEER_DOWN;

        if (n_ptr->block_setup) {
            tipc_node_unlock(n_ptr);
            goto cont;
        }

        /* Validate message sequence number info */
        seq_no = msg_seqno(msg);
        ackd = msg_ack(msg);

        /* Release acked messages */
        if (n_ptr->bclink.supported)
            tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));

        crs = l_ptr->first_out;
        while ((crs != l_ptr->next_out) &&
               less_eq(buf_seqno(crs), ackd)) {
            struct sk_buff *next = crs->next;

            kfree_skb(crs);
            crs = next;
            released++;
        }
        if (released) {
            l_ptr->first_out = crs;
            l_ptr->out_queue_size -= released;
        }

        /* Try sending any messages link endpoint has pending */
        if (unlikely(l_ptr->next_out))
            tipc_link_push_queue(l_ptr);
        if (unlikely(!list_empty(&l_ptr->waiting_ports)))
            tipc_link_wakeup_ports(l_ptr, 0);
        if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
            l_ptr->stats.sent_acks++;
            tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
        }

        /* Now (finally!) process the incoming message */
protocol_check:
        if (likely(link_working_working(l_ptr))) {
            if (likely(seq_no == mod(l_ptr->next_in_no))) {
                l_ptr->next_in_no++;
                if (unlikely(l_ptr->oldest_deferred_in))
                    head = link_insert_deferred_queue(l_ptr,
                                      head);
deliver:
                if (likely(msg_isdata(msg))) {
                    tipc_node_unlock(n_ptr);
                    tipc_port_recv_msg(buf);
                    continue;
                }
                switch (msg_user(msg)) {
                    int ret;
                case MSG_BUNDLER:
                    l_ptr->stats.recv_bundles++;
                    l_ptr->stats.recv_bundled +=
                        msg_msgcnt(msg);
                    tipc_node_unlock(n_ptr);
                    tipc_link_recv_bundle(buf);
                    continue;
                case NAME_DISTRIBUTOR:
                    tipc_node_unlock(n_ptr);
                    tipc_named_recv(buf);
                    continue;
                case CONN_MANAGER:
                    tipc_node_unlock(n_ptr);
                    tipc_port_recv_proto_msg(buf);
                    continue;
                case MSG_FRAGMENTER:
                    l_ptr->stats.recv_fragments++;
                    ret = tipc_link_recv_fragment(
                        &l_ptr->defragm_buf,
                        &buf, &msg);
                    if (ret == 1) {
                        l_ptr->stats.recv_fragmented++;
                        goto deliver;
                    }
                    if (ret == -1)
                        l_ptr->next_in_no--;
                    break;
                case CHANGEOVER_PROTOCOL:
                    type = msg_type(msg);
                    if (link_recv_changeover_msg(&l_ptr,
                                     &buf)) {
                        msg = buf_msg(buf);
                        seq_no = msg_seqno(msg);
                        if (type == ORIGINAL_MSG)
                            goto deliver;
                        goto protocol_check;
                    }
                    break;
                default:
                    kfree_skb(buf);
                    buf = NULL;
                    break;
                }
                tipc_node_unlock(n_ptr);
                tipc_net_route_msg(buf);
                continue;
            }
            link_handle_out_of_seq_msg(l_ptr, buf);
            head = link_insert_deferred_queue(l_ptr, head);
            tipc_node_unlock(n_ptr);
            continue;
        }

        if (msg_user(msg) == LINK_PROTOCOL) {
            link_recv_proto_msg(l_ptr, buf);
            head = link_insert_deferred_queue(l_ptr, head);
            tipc_node_unlock(n_ptr);
            continue;
        }
        link_state_event(l_ptr, TRAFFIC_MSG_EVT);

        if (link_working_working(l_ptr)) {
            /* Re-insert in front of queue */
            buf->next = head;
            head = buf;
            tipc_node_unlock(n_ptr);
            continue;
        }
        tipc_node_unlock(n_ptr);
cont:
        kfree_skb(buf);
    }
    read_unlock_bh(&tipc_net_lock);
}

u32 tipc_link_defer_pkt(struct sk_buff **head, struct sk_buff **tail,
            struct sk_buff *buf)
{
    struct sk_buff *queue_buf;
    struct sk_buff **prev;
    u32 seq_no = buf_seqno(buf);

    buf->next = NULL;

    /* Empty queue ? */
    if (*head == NULL) {
        *head = *tail = buf;
        return 1;
    }

    /* Last ? */
    if (less(buf_seqno(*tail), seq_no)) {
        (*tail)->next = buf;
        *tail = buf;
        return 1;
    }

    /* Locate insertion point in queue, then insert; discard if duplicate */
    prev = head;
    queue_buf = *head;
    for (;;) {
        u32 curr_seqno = buf_seqno(queue_buf);

        if (seq_no == curr_seqno) {
            kfree_skb(buf);
            return 0;
        }

        if (less(seq_no, curr_seqno))
            break;

        prev = &queue_buf->next;
        queue_buf = queue_buf->next;
    }

    buf->next = queue_buf;
    *prev = buf;
    return 1;
}

/*
 * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
 */
static void link_handle_out_of_seq_msg(struct tipc_link *l_ptr,
                       struct sk_buff *buf)
{
    u32 seq_no = buf_seqno(buf);

    if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
        link_recv_proto_msg(l_ptr, buf);
        return;
    }

    /* Record OOS packet arrival (force mismatch on next timeout) */
    l_ptr->checkpoint--;

    /*
     * Discard packet if a duplicate; otherwise add it to deferred queue
     * and notify peer of gap as per protocol specification
     */
    if (less(seq_no, mod(l_ptr->next_in_no))) {
        l_ptr->stats.duplicates++;
        kfree_skb(buf);
        return;
    }

    if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
                &l_ptr->newest_deferred_in, buf)) {
        l_ptr->deferred_inqueue_sz++;
        l_ptr->stats.deferred_recv++;
        if ((l_ptr->deferred_inqueue_sz % 16) == 1)
            tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
    } else
        l_ptr->stats.duplicates++;
}

/*
 * Send protocol message to the other endpoint.
 */
void tipc_link_send_proto_msg(struct tipc_link *l_ptr, u32 msg_typ,
                int probe_msg, u32 gap, u32 tolerance,
                u32 priority, u32 ack_mtu)
{
    struct sk_buff *buf = NULL;
    struct tipc_msg *msg = l_ptr->pmsg;
    u32 msg_size = sizeof(l_ptr->proto_msg);
    int r_flag;

    /* Discard any previous message that was deferred due to congestion */
    if (l_ptr->proto_msg_queue) {
        kfree_skb(l_ptr->proto_msg_queue);
        l_ptr->proto_msg_queue = NULL;
    }

    if (link_blocked(l_ptr))
        return;

    /* Abort non-RESET send if communication with node is prohibited */
    if ((l_ptr->owner->block_setup) && (msg_typ != RESET_MSG))
        return;

    /* Create protocol message with "out-of-sequence" sequence number */
    msg_set_type(msg, msg_typ);
    msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
    msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
    msg_set_last_bcast(msg, tipc_bclink_get_last_sent());

    if (msg_typ == STATE_MSG) {
        u32 next_sent = mod(l_ptr->next_out_no);

        if (!tipc_link_is_up(l_ptr))
            return;
        if (l_ptr->next_out)
            next_sent = buf_seqno(l_ptr->next_out);
        msg_set_next_sent(msg, next_sent);
        if (l_ptr->oldest_deferred_in) {
            u32 rec = buf_seqno(l_ptr->oldest_deferred_in);
            gap = mod(rec - mod(l_ptr->next_in_no));
        }
        msg_set_seq_gap(msg, gap);
        if (gap)
            l_ptr->stats.sent_nacks++;
        msg_set_link_tolerance(msg, tolerance);
        msg_set_linkprio(msg, priority);
        msg_set_max_pkt(msg, ack_mtu);
        msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
        msg_set_probe(msg, probe_msg != 0);
        if (probe_msg) {
            u32 mtu = l_ptr->max_pkt;

            if ((mtu < l_ptr->max_pkt_target) &&
                link_working_working(l_ptr) &&
                l_ptr->fsm_msg_cnt) {
                msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
                if (l_ptr->max_pkt_probes == 10) {
                    l_ptr->max_pkt_target = (msg_size - 4);
                    l_ptr->max_pkt_probes = 0;
                    msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
                }
                l_ptr->max_pkt_probes++;
            }

            l_ptr->stats.sent_probes++;
        }
        l_ptr->stats.sent_states++;
    } else {        /* RESET_MSG or ACTIVATE_MSG */
        msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
        msg_set_seq_gap(msg, 0);
        msg_set_next_sent(msg, 1);
        msg_set_probe(msg, 0);
        msg_set_link_tolerance(msg, l_ptr->tolerance);
        msg_set_linkprio(msg, l_ptr->priority);
        msg_set_max_pkt(msg, l_ptr->max_pkt_target);
    }

    r_flag = (l_ptr->owner->working_links > tipc_link_is_up(l_ptr));
    msg_set_redundant_link(msg, r_flag);
    msg_set_linkprio(msg, l_ptr->priority);
    msg_set_size(msg, msg_size);

    msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));

    buf = tipc_buf_acquire(msg_size);
    if (!buf)
        return;

    skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));

    /* Defer message if bearer is already congested */
    if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
        l_ptr->proto_msg_queue = buf;
        return;
    }

    /* Defer message if attempting to send results in bearer congestion */
    if (!tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
        tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
        l_ptr->proto_msg_queue = buf;
        l_ptr->stats.bearer_congs++;
        return;
    }

    /* Discard message if it was sent successfully */
    l_ptr->unacked_window = 0;
    kfree_skb(buf);
}

/*
 * Receive protocol message :
 * Note that network plane id propagates through the network, and may
 * change at any time. The node with lowest address rules
 */
static void link_recv_proto_msg(struct tipc_link *l_ptr, struct sk_buff *buf)
{
    u32 rec_gap = 0;
    u32 max_pkt_info;
    u32 max_pkt_ack;
    u32 msg_tol;
    struct tipc_msg *msg = buf_msg(buf);

    if (link_blocked(l_ptr))
        goto exit;

    /* record unnumbered packet arrival (force mismatch on next timeout) */
    l_ptr->checkpoint--;

    if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
        if (tipc_own_addr > msg_prevnode(msg))
            l_ptr->b_ptr->net_plane = msg_net_plane(msg);

    l_ptr->owner->permit_changeover = msg_redundant_link(msg);

    switch (msg_type(msg)) {

    case RESET_MSG:
        if (!link_working_unknown(l_ptr) &&
            (l_ptr->peer_session != INVALID_SESSION)) {
            if (less_eq(msg_session(msg), l_ptr->peer_session))
                break; /* duplicate or old reset: ignore */
        }

        if (!msg_redundant_link(msg) && (link_working_working(l_ptr) ||
                link_working_unknown(l_ptr))) {
            /*
             * peer has lost contact -- don't allow peer's links
             * to reactivate before we recognize loss & clean up
             */
            l_ptr->owner->block_setup = WAIT_NODE_DOWN;
        }

        link_state_event(l_ptr, RESET_MSG);

        /* fall thru' */
    case ACTIVATE_MSG:
        /* Update link settings according other endpoint's values */
        strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));

        msg_tol = msg_link_tolerance(msg);
        if (msg_tol > l_ptr->tolerance)
            link_set_supervision_props(l_ptr, msg_tol);

        if (msg_linkprio(msg) > l_ptr->priority)
            l_ptr->priority = msg_linkprio(msg);

        max_pkt_info = msg_max_pkt(msg);
        if (max_pkt_info) {
            if (max_pkt_info < l_ptr->max_pkt_target)
                l_ptr->max_pkt_target = max_pkt_info;
            if (l_ptr->max_pkt > l_ptr->max_pkt_target)
                l_ptr->max_pkt = l_ptr->max_pkt_target;
        } else {
            l_ptr->max_pkt = l_ptr->max_pkt_target;
        }
        l_ptr->owner->bclink.supportable = (max_pkt_info != 0);

        /* Synchronize broadcast link info, if not done previously */
        if (!tipc_node_is_up(l_ptr->owner)) {
            l_ptr->owner->bclink.last_sent =
                l_ptr->owner->bclink.last_in =
                msg_last_bcast(msg);
            l_ptr->owner->bclink.oos_state = 0;
        }

        l_ptr->peer_session = msg_session(msg);
        l_ptr->peer_bearer_id = msg_bearer_id(msg);

        if (msg_type(msg) == ACTIVATE_MSG)
            link_state_event(l_ptr, ACTIVATE_MSG);
        break;
    case STATE_MSG:

        msg_tol = msg_link_tolerance(msg);
        if (msg_tol)
            link_set_supervision_props(l_ptr, msg_tol);

        if (msg_linkprio(msg) &&
            (msg_linkprio(msg) != l_ptr->priority)) {
            pr_warn("%s<%s>, priority change %u->%u\n",
                link_rst_msg, l_ptr->name, l_ptr->priority,
                msg_linkprio(msg));
            l_ptr->priority = msg_linkprio(msg);
            tipc_link_reset(l_ptr); /* Enforce change to take effect */
            break;
        }
        link_state_event(l_ptr, TRAFFIC_MSG_EVT);
        l_ptr->stats.recv_states++;
        if (link_reset_unknown(l_ptr))
            break;

        if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
            rec_gap = mod(msg_next_sent(msg) -
                      mod(l_ptr->next_in_no));
        }

        max_pkt_ack = msg_max_pkt(msg);
        if (max_pkt_ack > l_ptr->max_pkt) {
            l_ptr->max_pkt = max_pkt_ack;
            l_ptr->max_pkt_probes = 0;
        }

        max_pkt_ack = 0;
        if (msg_probe(msg)) {
            l_ptr->stats.recv_probes++;
            if (msg_size(msg) > sizeof(l_ptr->proto_msg))
                max_pkt_ack = msg_size(msg);
        }

        /* Protocol message before retransmits, reduce loss risk */
        if (l_ptr->owner->bclink.supported)
            tipc_bclink_update_link_state(l_ptr->owner,
                              msg_last_bcast(msg));

        if (rec_gap || (msg_probe(msg))) {
            tipc_link_send_proto_msg(l_ptr, STATE_MSG,
                         0, rec_gap, 0, 0, max_pkt_ack);
        }
        if (msg_seq_gap(msg)) {
            l_ptr->stats.recv_nacks++;
            tipc_link_retransmit(l_ptr, l_ptr->first_out,
                         msg_seq_gap(msg));
        }
        break;
    }
exit:
    kfree_skb(buf);
}


/*
 * tipc_link_tunnel(): Send one message via a link belonging to
 * another bearer. Owner node is locked.
 */
static void tipc_link_tunnel(struct tipc_link *l_ptr,
                 struct tipc_msg *tunnel_hdr,
                 struct tipc_msg  *msg,
                 u32 selector)
{
    struct tipc_link *tunnel;
    struct sk_buff *buf;
    u32 length = msg_size(msg);

    tunnel = l_ptr->owner->active_links[selector & 1];
    if (!tipc_link_is_up(tunnel)) {
        pr_warn("%stunnel link no longer available\n", link_co_err);
        return;
    }
    msg_set_size(tunnel_hdr, length + INT_H_SIZE);
    buf = tipc_buf_acquire(length + INT_H_SIZE);
    if (!buf) {
        pr_warn("%sunable to send tunnel msg\n", link_co_err);
        return;
    }
    skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
    skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
    tipc_link_send_buf(tunnel, buf);
}



/*
 * changeover(): Send whole message queue via the remaining link
 *               Owner node is locked.
 */
void tipc_link_changeover(struct tipc_link *l_ptr)
{
    u32 msgcount = l_ptr->out_queue_size;
    struct sk_buff *crs = l_ptr->first_out;
    struct tipc_link *tunnel = l_ptr->owner->active_links[0];
    struct tipc_msg tunnel_hdr;
    int split_bundles;

    if (!tunnel)
        return;

    if (!l_ptr->owner->permit_changeover) {
        pr_warn("%speer did not permit changeover\n", link_co_err);
        return;
    }

    tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
         ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
    msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
    msg_set_msgcnt(&tunnel_hdr, msgcount);

    if (!l_ptr->first_out) {
        struct sk_buff *buf;

        buf = tipc_buf_acquire(INT_H_SIZE);
        if (buf) {
            skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
            msg_set_size(&tunnel_hdr, INT_H_SIZE);
            tipc_link_send_buf(tunnel, buf);
        } else {
            pr_warn("%sunable to send changeover msg\n",
                link_co_err);
        }
        return;
    }

    split_bundles = (l_ptr->owner->active_links[0] !=
             l_ptr->owner->active_links[1]);

    while (crs) {
        struct tipc_msg *msg = buf_msg(crs);

        if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
            struct tipc_msg *m = msg_get_wrapped(msg);
            unchar *pos = (unchar *)m;

            msgcount = msg_msgcnt(msg);
            while (msgcount--) {
                msg_set_seqno(m, msg_seqno(msg));
                tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
                         msg_link_selector(m));
                pos += align(msg_size(m));
                m = (struct tipc_msg *)pos;
            }
        } else {
            tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
                     msg_link_selector(msg));
        }
        crs = crs->next;
    }
}

void tipc_link_send_duplicate(struct tipc_link *l_ptr, struct tipc_link *tunnel)
{
    struct sk_buff *iter;
    struct tipc_msg tunnel_hdr;

    tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
         DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
    msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
    msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
    iter = l_ptr->first_out;
    while (iter) {
        struct sk_buff *outbuf;
        struct tipc_msg *msg = buf_msg(iter);
        u32 length = msg_size(msg);

        if (msg_user(msg) == MSG_BUNDLER)
            msg_set_type(msg, CLOSED_MSG);
        msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
        msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
        msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
        outbuf = tipc_buf_acquire(length + INT_H_SIZE);
        if (outbuf == NULL) {
            pr_warn("%sunable to send duplicate msg\n",
                link_co_err);
            return;
        }
        skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
        skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
                           length);
        tipc_link_send_buf(tunnel, outbuf);
        if (!tipc_link_is_up(l_ptr))
            return;
        iter = iter->next;
    }
}

static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
{
    struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
    u32 size = msg_size(msg);
    struct sk_buff *eb;

    eb = tipc_buf_acquire(size);
    if (eb)
        skb_copy_to_linear_data(eb, msg, size);
    return eb;
}

/*
 *  link_recv_changeover_msg(): Receive tunneled packet sent
 *  via other link. Node is locked. Return extracted buffer.
 */
static int link_recv_changeover_msg(struct tipc_link **l_ptr,
                    struct sk_buff **buf)
{
    struct sk_buff *tunnel_buf = *buf;
    struct tipc_link *dest_link;
    struct tipc_msg *msg;
    struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
    u32 msg_typ = msg_type(tunnel_msg);
    u32 msg_count = msg_msgcnt(tunnel_msg);

    dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
    if (!dest_link)
        goto exit;
    if (dest_link == *l_ptr) {
        pr_err("Unexpected changeover message on link <%s>\n",
               (*l_ptr)->name);
        goto exit;
    }
    *l_ptr = dest_link;
    msg = msg_get_wrapped(tunnel_msg);

    if (msg_typ == DUPLICATE_MSG) {
        if (less(msg_seqno(msg), mod(dest_link->next_in_no)))
            goto exit;
        *buf = buf_extract(tunnel_buf, INT_H_SIZE);
        if (*buf == NULL) {
            pr_warn("%sduplicate msg dropped\n", link_co_err);
            goto exit;
        }
        kfree_skb(tunnel_buf);
        return 1;
    }

    /* First original message ?: */
    if (tipc_link_is_up(dest_link)) {
        pr_info("%s<%s>, changeover initiated by peer\n", link_rst_msg,
            dest_link->name);
        tipc_link_reset(dest_link);
        dest_link->exp_msg_count = msg_count;
        if (!msg_count)
            goto exit;
    } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
        dest_link->exp_msg_count = msg_count;
        if (!msg_count)
            goto exit;
    }

    /* Receive original message */
    if (dest_link->exp_msg_count == 0) {
        pr_warn("%sgot too many tunnelled messages\n", link_co_err);
        goto exit;
    }
    dest_link->exp_msg_count--;
    if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
        goto exit;
    } else {
        *buf = buf_extract(tunnel_buf, INT_H_SIZE);
        if (*buf != NULL) {
            kfree_skb(tunnel_buf);
            return 1;
        } else {
            pr_warn("%soriginal msg dropped\n", link_co_err);
        }
    }
exit:
    *buf = NULL;
    kfree_skb(tunnel_buf);
    return 0;
}

/*
 *  Bundler functionality:
 */
void tipc_link_recv_bundle(struct sk_buff *buf)
{
    u32 msgcount = msg_msgcnt(buf_msg(buf));
    u32 pos = INT_H_SIZE;
    struct sk_buff *obuf;

    while (msgcount--) {
        obuf = buf_extract(buf, pos);
        if (obuf == NULL) {
            pr_warn("Link unable to unbundle message(s)\n");
            break;
        }
        pos += align(msg_size(buf_msg(obuf)));
        tipc_net_route_msg(obuf);
    }
    kfree_skb(buf);
}

/*
 *  Fragmentation/defragmentation:
 */

/*
 * link_send_long_buf: Entry for buffers needing fragmentation.
 * The buffer is complete, inclusive total message length.
 * Returns user data length.
 */
static int link_send_long_buf(struct tipc_link *l_ptr, struct sk_buff *buf)
{
    struct sk_buff *buf_chain = NULL;
    struct sk_buff *buf_chain_tail = (struct sk_buff *)&buf_chain;
    struct tipc_msg *inmsg = buf_msg(buf);
    struct tipc_msg fragm_hdr;
    u32 insize = msg_size(inmsg);
    u32 dsz = msg_data_sz(inmsg);
    unchar *crs = buf->data;
    u32 rest = insize;
    u32 pack_sz = l_ptr->max_pkt;
    u32 fragm_sz = pack_sz - INT_H_SIZE;
    u32 fragm_no = 0;
    u32 destaddr;

    if (msg_short(inmsg))
        destaddr = l_ptr->addr;
    else
        destaddr = msg_destnode(inmsg);

    /* Prepare reusable fragment header: */
    tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
         INT_H_SIZE, destaddr);

    /* Chop up message: */
    while (rest > 0) {
        struct sk_buff *fragm;

        if (rest <= fragm_sz) {
            fragm_sz = rest;
            msg_set_type(&fragm_hdr, LAST_FRAGMENT);
        }
        fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
        if (fragm == NULL) {
            kfree_skb(buf);
            while (buf_chain) {
                buf = buf_chain;
                buf_chain = buf_chain->next;
                kfree_skb(buf);
            }
            return -ENOMEM;
        }
        msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
        fragm_no++;
        msg_set_fragm_no(&fragm_hdr, fragm_no);
        skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
        skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
                           fragm_sz);
        buf_chain_tail->next = fragm;
        buf_chain_tail = fragm;

        rest -= fragm_sz;
        crs += fragm_sz;
        msg_set_type(&fragm_hdr, FRAGMENT);
    }
    kfree_skb(buf);

    /* Append chain of fragments to send queue & send them */
    l_ptr->long_msg_seq_no++;
    link_add_chain_to_outqueue(l_ptr, buf_chain, l_ptr->long_msg_seq_no);
    l_ptr->stats.sent_fragments += fragm_no;
    l_ptr->stats.sent_fragmented++;
    tipc_link_push_queue(l_ptr);

    return dsz;
}

/*
 * A pending message being re-assembled must store certain values
 * to handle subsequent fragments correctly. The following functions
 * help storing these values in unused, available fields in the
 * pending message. This makes dynamic memory allocation unnecessary.
 */
static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
{
    msg_set_seqno(buf_msg(buf), seqno);
}

static u32 get_fragm_size(struct sk_buff *buf)
{
    return msg_ack(buf_msg(buf));
}

static void set_fragm_size(struct sk_buff *buf, u32 sz)
{
    msg_set_ack(buf_msg(buf), sz);
}

static u32 get_expected_frags(struct sk_buff *buf)
{
    return msg_bcast_ack(buf_msg(buf));
}

static void set_expected_frags(struct sk_buff *buf, u32 exp)
{
    msg_set_bcast_ack(buf_msg(buf), exp);
}

static u32 get_timer_cnt(struct sk_buff *buf)
{
    return msg_reroute_cnt(buf_msg(buf));
}

static void incr_timer_cnt(struct sk_buff *buf)
{
    msg_incr_reroute_cnt(buf_msg(buf));
}

/*
 * tipc_link_recv_fragment(): Called with node lock on. Returns
 * the reassembled buffer if message is complete.
 */
int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
                struct tipc_msg **m)
{
    struct sk_buff *prev = NULL;
    struct sk_buff *fbuf = *fb;
    struct tipc_msg *fragm = buf_msg(fbuf);
    struct sk_buff *pbuf = *pending;
    u32 long_msg_seq_no = msg_long_msgno(fragm);

    *fb = NULL;

    /* Is there an incomplete message waiting for this fragment? */
    while (pbuf && ((buf_seqno(pbuf) != long_msg_seq_no) ||
            (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
        prev = pbuf;
        pbuf = pbuf->next;
    }

    if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
        struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
        u32 msg_sz = msg_size(imsg);
        u32 fragm_sz = msg_data_sz(fragm);
        u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
        u32 max =  TIPC_MAX_USER_MSG_SIZE + NAMED_H_SIZE;
        if (msg_type(imsg) == TIPC_MCAST_MSG)
            max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
        if (msg_size(imsg) > max) {
            kfree_skb(fbuf);
            return 0;
        }
        pbuf = tipc_buf_acquire(msg_size(imsg));
        if (pbuf != NULL) {
            pbuf->next = *pending;
            *pending = pbuf;
            skb_copy_to_linear_data(pbuf, imsg,
                        msg_data_sz(fragm));
            /*  Prepare buffer for subsequent fragments. */
            set_long_msg_seqno(pbuf, long_msg_seq_no);
            set_fragm_size(pbuf, fragm_sz);
            set_expected_frags(pbuf, exp_fragm_cnt - 1);
        } else {
            pr_debug("Link unable to reassemble fragmented message\n");
            kfree_skb(fbuf);
            return -1;
        }
        kfree_skb(fbuf);
        return 0;
    } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
        u32 dsz = msg_data_sz(fragm);
        u32 fsz = get_fragm_size(pbuf);
        u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
        u32 exp_frags = get_expected_frags(pbuf) - 1;
        skb_copy_to_linear_data_offset(pbuf, crs,
                           msg_data(fragm), dsz);
        kfree_skb(fbuf);

        /* Is message complete? */
        if (exp_frags == 0) {
            if (prev)
                prev->next = pbuf->next;
            else
                *pending = pbuf->next;
            msg_reset_reroute_cnt(buf_msg(pbuf));
            *fb = pbuf;
            *m = buf_msg(pbuf);
            return 1;
        }
        set_expected_frags(pbuf, exp_frags);
        return 0;
    }
    kfree_skb(fbuf);
    return 0;
}

static void link_check_defragm_bufs(struct tipc_link *l_ptr)
{
    struct sk_buff *prev = NULL;
    struct sk_buff *next = NULL;
    struct sk_buff *buf = l_ptr->defragm_buf;

    if (!buf)
        return;
    if (!link_working_working(l_ptr))
        return;
    while (buf) {
        u32 cnt = get_timer_cnt(buf);

        next = buf->next;
        if (cnt < 4) {
            incr_timer_cnt(buf);
            prev = buf;
        } else {
            if (prev)
                prev->next = buf->next;
            else
                l_ptr->defragm_buf = buf->next;
            kfree_skb(buf);
        }
        buf = next;
    }
}

static void link_set_supervision_props(struct tipc_link *l_ptr, u32 tolerance)
{
    if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
        return;

    l_ptr->tolerance = tolerance;
    l_ptr->continuity_interval =
        ((tolerance / 4) > 500) ? 500 : tolerance / 4;
    l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
}

void tipc_link_set_queue_limits(struct tipc_link *l_ptr, u32 window)
{
    /* Data messages from this node, inclusive FIRST_FRAGM */
    l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
    l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
    l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
    l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
    /* Transiting data messages,inclusive FIRST_FRAGM */
    l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
    l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
    l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
    l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
    l_ptr->queue_limit[CONN_MANAGER] = 1200;
    l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
    l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
    /* FRAGMENT and LAST_FRAGMENT packets */
    l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
}

static struct tipc_link *link_find_link(const char *name,
                    struct tipc_node **node)
{
    struct tipc_link_name link_name_parts;
    struct tipc_bearer *b_ptr;
    struct tipc_link *l_ptr;

    if (!link_name_validate(name, &link_name_parts))
        return NULL;

    b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
    if (!b_ptr)
        return NULL;

    *node = tipc_node_find(link_name_parts.addr_peer);
    if (!*node)
        return NULL;

    l_ptr = (*node)->links[b_ptr->identity];
    if (!l_ptr || strcmp(l_ptr->name, name))
        return NULL;

    return l_ptr;
}

static int link_value_is_valid(u16 cmd, u32 new_value)
{
    switch (cmd) {
    case TIPC_CMD_SET_LINK_TOL:
        return (new_value >= TIPC_MIN_LINK_TOL) &&
            (new_value <= TIPC_MAX_LINK_TOL);
    case TIPC_CMD_SET_LINK_PRI:
        return (new_value <= TIPC_MAX_LINK_PRI);
    case TIPC_CMD_SET_LINK_WINDOW:
        return (new_value >= TIPC_MIN_LINK_WIN) &&
            (new_value <= TIPC_MAX_LINK_WIN);
    }
    return 0;
}

static int link_cmd_set_value(const char *name, u32 new_value, u16 cmd)
{
    struct tipc_node *node;
    struct tipc_link *l_ptr;
    struct tipc_bearer *b_ptr;
    struct tipc_media *m_ptr;

    l_ptr = link_find_link(name, &node);
    if (l_ptr) {
        /*
         * acquire node lock for tipc_link_send_proto_msg().
         * see "TIPC locking policy" in net.c.
         */
        tipc_node_lock(node);
        switch (cmd) {
        case TIPC_CMD_SET_LINK_TOL:
            link_set_supervision_props(l_ptr, new_value);
            tipc_link_send_proto_msg(l_ptr,
                STATE_MSG, 0, 0, new_value, 0, 0);
            break;
        case TIPC_CMD_SET_LINK_PRI:
            l_ptr->priority = new_value;
            tipc_link_send_proto_msg(l_ptr,
                STATE_MSG, 0, 0, 0, new_value, 0);
            break;
        case TIPC_CMD_SET_LINK_WINDOW:
            tipc_link_set_queue_limits(l_ptr, new_value);
            break;
        }
        tipc_node_unlock(node);
        return 0;
    }

    b_ptr = tipc_bearer_find(name);
    if (b_ptr) {
        switch (cmd) {
        case TIPC_CMD_SET_LINK_TOL:
            b_ptr->tolerance = new_value;
            return 0;
        case TIPC_CMD_SET_LINK_PRI:
            b_ptr->priority = new_value;
            return 0;
        case TIPC_CMD_SET_LINK_WINDOW:
            b_ptr->window = new_value;
            return 0;
        }
        return -EINVAL;
    }

    m_ptr = tipc_media_find(name);
    if (!m_ptr)
        return -ENODEV;
    switch (cmd) {
    case TIPC_CMD_SET_LINK_TOL:
        m_ptr->tolerance = new_value;
        return 0;
    case TIPC_CMD_SET_LINK_PRI:
        m_ptr->priority = new_value;
        return 0;
    case TIPC_CMD_SET_LINK_WINDOW:
        m_ptr->window = new_value;
        return 0;
    }
    return -EINVAL;
}

struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
                     u16 cmd)
{
    struct tipc_link_config *args;
    u32 new_value;
    int res;

    if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
        return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

    args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
    new_value = ntohl(args->value);

    if (!link_value_is_valid(cmd, new_value))
        return tipc_cfg_reply_error_string(
            "cannot change, value invalid");

    if (!strcmp(args->name, tipc_bclink_name)) {
        if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
            (tipc_bclink_set_queue_limits(new_value) == 0))
            return tipc_cfg_reply_none();
        return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                           " (cannot change setting on broadcast link)");
    }

    read_lock_bh(&tipc_net_lock);
    res = link_cmd_set_value(args->name, new_value, cmd);
    read_unlock_bh(&tipc_net_lock);
    if (res)
        return tipc_cfg_reply_error_string("cannot change link setting");

    return tipc_cfg_reply_none();
}

static void link_reset_statistics(struct tipc_link *l_ptr)
{
    memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
    l_ptr->stats.sent_info = l_ptr->next_out_no;
    l_ptr->stats.recv_info = l_ptr->next_in_no;
}

struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
{
    char *link_name;
    struct tipc_link *l_ptr;
    struct tipc_node *node;

    if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
        return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

    link_name = (char *)TLV_DATA(req_tlv_area);
    if (!strcmp(link_name, tipc_bclink_name)) {
        if (tipc_bclink_reset_stats())
            return tipc_cfg_reply_error_string("link not found");
        return tipc_cfg_reply_none();
    }

    read_lock_bh(&tipc_net_lock);
    l_ptr = link_find_link(link_name, &node);
    if (!l_ptr) {
        read_unlock_bh(&tipc_net_lock);
        return tipc_cfg_reply_error_string("link not found");
    }

    tipc_node_lock(node);
    link_reset_statistics(l_ptr);
    tipc_node_unlock(node);
    read_unlock_bh(&tipc_net_lock);
    return tipc_cfg_reply_none();
}

static u32 percent(u32 count, u32 total)
{
    return (count * 100 + (total / 2)) / total;
}

static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
{
    struct tipc_link *l;
    struct tipc_stats *s;
    struct tipc_node *node;
    char *status;
    u32 profile_total = 0;
    int ret;

    if (!strcmp(name, tipc_bclink_name))
        return tipc_bclink_stats(buf, buf_size);

    read_lock_bh(&tipc_net_lock);
    l = link_find_link(name, &node);
    if (!l) {
        read_unlock_bh(&tipc_net_lock);
        return 0;
    }
    tipc_node_lock(node);
    s = &l->stats;

    if (tipc_link_is_active(l))
        status = "ACTIVE";
    else if (tipc_link_is_up(l))
        status = "STANDBY";
    else
        status = "DEFUNCT";

    ret = tipc_snprintf(buf, buf_size, "Link <%s>\n"
                "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
                "  Window:%u packets\n",
                l->name, status, l->max_pkt, l->priority,
                l->tolerance, l->queue_limit[0]);

    ret += tipc_snprintf(buf + ret, buf_size - ret,
                 "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
                 l->next_in_no - 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",
                 l->next_out_no - s->sent_info, s->sent_fragments,
                 s->sent_fragmented, s->sent_bundles,
                 s->sent_bundled);

    profile_total = s->msg_length_counts;
    if (!profile_total)
        profile_total = 1;

    ret += tipc_snprintf(buf + ret, buf_size - ret,
                 "  TX profile sample:%u packets  average:%u octets\n"
                 "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
                 "-16384:%u%% -32768:%u%% -66000:%u%%\n",
                 s->msg_length_counts,
                 s->msg_lengths_total / profile_total,
                 percent(s->msg_length_profile[0], profile_total),
                 percent(s->msg_length_profile[1], profile_total),
                 percent(s->msg_length_profile[2], profile_total),
                 percent(s->msg_length_profile[3], profile_total),
                 percent(s->msg_length_profile[4], profile_total),
                 percent(s->msg_length_profile[5], profile_total),
                 percent(s->msg_length_profile[6], profile_total));

    ret += tipc_snprintf(buf + ret, buf_size - ret,
                 "  RX states:%u probes:%u naks:%u defs:%u"
                 " dups:%u\n", s->recv_states, s->recv_probes,
                 s->recv_nacks, s->deferred_recv, s->duplicates);

    ret += tipc_snprintf(buf + ret, buf_size - ret,
                 "  TX states:%u probes:%u naks:%u acks:%u"
                 " dups:%u\n", s->sent_states, s->sent_probes,
                 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);

    tipc_node_unlock(node);
    read_unlock_bh(&tipc_net_lock);
    return ret;
}

struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
{
    struct sk_buff *buf;
    struct tlv_desc *rep_tlv;
    int str_len;
    int pb_len;
    char *pb;

    if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
        return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

    buf = tipc_cfg_reply_alloc(TLV_SPACE(ULTRA_STRING_MAX_LEN));
    if (!buf)
        return NULL;

    rep_tlv = (struct tlv_desc *)buf->data;
    pb = TLV_DATA(rep_tlv);
    pb_len = ULTRA_STRING_MAX_LEN;
    str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
                  pb, pb_len);
    if (!str_len) {
        kfree_skb(buf);
        return tipc_cfg_reply_error_string("link not found");
    }
    str_len += 1;   /* for "\0" */
    skb_put(buf, TLV_SPACE(str_len));
    TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);

    return buf;
}

u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
{
    struct tipc_node *n_ptr;
    struct tipc_link *l_ptr;
    u32 res = MAX_PKT_DEFAULT;

    if (dest == tipc_own_addr)
        return MAX_MSG_SIZE;

    read_lock_bh(&tipc_net_lock);
    n_ptr = tipc_node_find(dest);
    if (n_ptr) {
        tipc_node_lock(n_ptr);
        l_ptr = n_ptr->active_links[selector & 1];
        if (l_ptr)
            res = l_ptr->max_pkt;
        tipc_node_unlock(n_ptr);
    }
    read_unlock_bh(&tipc_net_lock);
    return res;
}

static void link_print(struct tipc_link *l_ptr, const char *str)
{
    pr_info("%s Link %x<%s>:", str, l_ptr->addr, l_ptr->b_ptr->name);

    if (link_working_unknown(l_ptr))
        pr_cont(":WU\n");
    else if (link_reset_reset(l_ptr))
        pr_cont(":RR\n");
    else if (link_reset_unknown(l_ptr))
        pr_cont(":RU\n");
    else if (link_working_working(l_ptr))
        pr_cont(":WW\n");
    else
        pr_cont("\n");
}