bearer.c

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/*
 * net/tipc/bearer.c: TIPC bearer code
 *
 * Copyright (c) 1996-2006, Ericsson AB
 * Copyright (c) 2004-2006, 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 "config.h"
#include "bearer.h"
#include "discover.h"

#define MAX_ADDR_STR 32

static struct tipc_media *media_list[MAX_MEDIA];
static u32 media_count;

struct tipc_bearer tipc_bearers[MAX_BEARERS];

static void bearer_disable(struct tipc_bearer *b_ptr);

struct tipc_media *tipc_media_find(const char *name)
{
    u32 i;

    for (i = 0; i < media_count; i++) {
        if (!strcmp(media_list[i]->name, name))
            return media_list[i];
    }
    return NULL;
}

static struct tipc_media *media_find_id(u8 type)
{
    u32 i;

    for (i = 0; i < media_count; i++) {
        if (media_list[i]->type_id == type)
            return media_list[i];
    }
    return NULL;
}

int tipc_register_media(struct tipc_media *m_ptr)
{
    int res = -EINVAL;

    write_lock_bh(&tipc_net_lock);

    if ((strlen(m_ptr->name) + 1) > TIPC_MAX_MEDIA_NAME)
        goto exit;
    if ((m_ptr->bcast_addr.media_id != m_ptr->type_id) ||
        !m_ptr->bcast_addr.broadcast)
        goto exit;
    if (m_ptr->priority > TIPC_MAX_LINK_PRI)
        goto exit;
    if ((m_ptr->tolerance < TIPC_MIN_LINK_TOL) ||
        (m_ptr->tolerance > TIPC_MAX_LINK_TOL))
        goto exit;
    if (media_count >= MAX_MEDIA)
        goto exit;
    if (tipc_media_find(m_ptr->name) || media_find_id(m_ptr->type_id))
        goto exit;

    media_list[media_count] = m_ptr;
    media_count++;
    res = 0;
exit:
    write_unlock_bh(&tipc_net_lock);
    if (res)
        pr_warn("Media <%s> registration error\n", m_ptr->name);
    return res;
}

void tipc_media_addr_printf(char *buf, int len, struct tipc_media_addr *a)
{
    char addr_str[MAX_ADDR_STR];
    struct tipc_media *m_ptr;
    int ret;

    m_ptr = media_find_id(a->media_id);

    if (m_ptr && !m_ptr->addr2str(a, addr_str, sizeof(addr_str)))
        ret = tipc_snprintf(buf, len, "%s(%s)", m_ptr->name, addr_str);
    else {
        u32 i;

        ret = tipc_snprintf(buf, len, "UNKNOWN(%u)", a->media_id);
        for (i = 0; i < sizeof(a->value); i++)
            ret += tipc_snprintf(buf - ret, len + ret,
                        "-%02x", a->value[i]);
    }
}

struct sk_buff *tipc_media_get_names(void)
{
    struct sk_buff *buf;
    int i;

    buf = tipc_cfg_reply_alloc(MAX_MEDIA * TLV_SPACE(TIPC_MAX_MEDIA_NAME));
    if (!buf)
        return NULL;

    read_lock_bh(&tipc_net_lock);
    for (i = 0; i < media_count; i++) {
        tipc_cfg_append_tlv(buf, TIPC_TLV_MEDIA_NAME,
                    media_list[i]->name,
                    strlen(media_list[i]->name) + 1);
    }
    read_unlock_bh(&tipc_net_lock);
    return buf;
}

static int bearer_name_validate(const char *name,
                struct tipc_bearer_names *name_parts)
{
    char name_copy[TIPC_MAX_BEARER_NAME];
    char *media_name;
    char *if_name;
    u32 media_len;
    u32 if_len;

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

    /* ensure all component parts of bearer name are present */
    media_name = name_copy;
    if_name = strchr(media_name, ':');
    if (if_name == NULL)
        return 0;
    *(if_name++) = 0;
    media_len = if_name - media_name;
    if_len = strlen(if_name) + 1;

    /* validate component parts of bearer name */
    if ((media_len <= 1) || (media_len > TIPC_MAX_MEDIA_NAME) ||
        (if_len <= 1) || (if_len > TIPC_MAX_IF_NAME))
        return 0;

    /* return bearer name components, if necessary */
    if (name_parts) {
        strcpy(name_parts->media_name, media_name);
        strcpy(name_parts->if_name, if_name);
    }
    return 1;
}

struct tipc_bearer *tipc_bearer_find(const char *name)
{
    struct tipc_bearer *b_ptr;
    u32 i;

    for (i = 0, b_ptr = tipc_bearers; i < MAX_BEARERS; i++, b_ptr++) {
        if (b_ptr->active && (!strcmp(b_ptr->name, name)))
            return b_ptr;
    }
    return NULL;
}

struct tipc_bearer *tipc_bearer_find_interface(const char *if_name)
{
    struct tipc_bearer *b_ptr;
    char *b_if_name;
    u32 i;

    for (i = 0, b_ptr = tipc_bearers; i < MAX_BEARERS; i++, b_ptr++) {
        if (!b_ptr->active)
            continue;
        b_if_name = strchr(b_ptr->name, ':') + 1;
        if (!strcmp(b_if_name, if_name))
            return b_ptr;
    }
    return NULL;
}

struct sk_buff *tipc_bearer_get_names(void)
{
    struct sk_buff *buf;
    struct tipc_bearer *b_ptr;
    int i, j;

    buf = tipc_cfg_reply_alloc(MAX_BEARERS * TLV_SPACE(TIPC_MAX_BEARER_NAME));
    if (!buf)
        return NULL;

    read_lock_bh(&tipc_net_lock);
    for (i = 0; i < media_count; i++) {
        for (j = 0; j < MAX_BEARERS; j++) {
            b_ptr = &tipc_bearers[j];
            if (b_ptr->active && (b_ptr->media == media_list[i])) {
                tipc_cfg_append_tlv(buf, TIPC_TLV_BEARER_NAME,
                            b_ptr->name,
                            strlen(b_ptr->name) + 1);
            }
        }
    }
    read_unlock_bh(&tipc_net_lock);
    return buf;
}

void tipc_bearer_add_dest(struct tipc_bearer *b_ptr, u32 dest)
{
    tipc_nmap_add(&b_ptr->nodes, dest);
    tipc_bcbearer_sort();
    tipc_disc_add_dest(b_ptr->link_req);
}

void tipc_bearer_remove_dest(struct tipc_bearer *b_ptr, u32 dest)
{
    tipc_nmap_remove(&b_ptr->nodes, dest);
    tipc_bcbearer_sort();
    tipc_disc_remove_dest(b_ptr->link_req);
}

/*
 * bearer_push(): Resolve bearer congestion. Force the waiting
 * links to push out their unsent packets, one packet per link
 * per iteration, until all packets are gone or congestion reoccurs.
 * 'tipc_net_lock' is read_locked when this function is called
 * bearer.lock must be taken before calling
 * Returns binary true(1) ore false(0)
 */
static int bearer_push(struct tipc_bearer *b_ptr)
{
    u32 res = 0;
    struct tipc_link *ln, *tln;

    if (b_ptr->blocked)
        return 0;

    while (!list_empty(&b_ptr->cong_links) && (res != PUSH_FAILED)) {
        list_for_each_entry_safe(ln, tln, &b_ptr->cong_links, link_list) {
            res = tipc_link_push_packet(ln);
            if (res == PUSH_FAILED)
                break;
            if (res == PUSH_FINISHED)
                list_move_tail(&ln->link_list, &b_ptr->links);
        }
    }
    return list_empty(&b_ptr->cong_links);
}

void tipc_bearer_lock_push(struct tipc_bearer *b_ptr)
{
    spin_lock_bh(&b_ptr->lock);
    bearer_push(b_ptr);
    spin_unlock_bh(&b_ptr->lock);
}


/*
 * Interrupt enabling new requests after bearer congestion or blocking:
 * See bearer_send().
 */
void tipc_continue(struct tipc_bearer *b_ptr)
{
    spin_lock_bh(&b_ptr->lock);
    if (!list_empty(&b_ptr->cong_links))
        tipc_k_signal((Handler)tipc_bearer_lock_push, (unsigned long)b_ptr);
    b_ptr->blocked = 0;
    spin_unlock_bh(&b_ptr->lock);
}

/*
 * Schedule link for sending of messages after the bearer
 * has been deblocked by 'continue()'. This method is called
 * when somebody tries to send a message via this link while
 * the bearer is congested. 'tipc_net_lock' is in read_lock here
 * bearer.lock is busy
 */
static void tipc_bearer_schedule_unlocked(struct tipc_bearer *b_ptr,
                        struct tipc_link *l_ptr)
{
    list_move_tail(&l_ptr->link_list, &b_ptr->cong_links);
}

/*
 * Schedule link for sending of messages after the bearer
 * has been deblocked by 'continue()'. This method is called
 * when somebody tries to send a message via this link while
 * the bearer is congested. 'tipc_net_lock' is in read_lock here,
 * bearer.lock is free
 */
void tipc_bearer_schedule(struct tipc_bearer *b_ptr, struct tipc_link *l_ptr)
{
    spin_lock_bh(&b_ptr->lock);
    tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
    spin_unlock_bh(&b_ptr->lock);
}


/*
 * tipc_bearer_resolve_congestion(): Check if there is bearer congestion,
 * and if there is, try to resolve it before returning.
 * 'tipc_net_lock' is read_locked when this function is called
 */
int tipc_bearer_resolve_congestion(struct tipc_bearer *b_ptr,
                    struct tipc_link *l_ptr)
{
    int res = 1;

    if (list_empty(&b_ptr->cong_links))
        return 1;
    spin_lock_bh(&b_ptr->lock);
    if (!bearer_push(b_ptr)) {
        tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
        res = 0;
    }
    spin_unlock_bh(&b_ptr->lock);
    return res;
}

int tipc_bearer_congested(struct tipc_bearer *b_ptr, struct tipc_link *l_ptr)
{
    if (unlikely(b_ptr->blocked))
        return 1;
    if (likely(list_empty(&b_ptr->cong_links)))
        return 0;
    return !tipc_bearer_resolve_congestion(b_ptr, l_ptr);
}

int tipc_enable_bearer(const char *name, u32 disc_domain, u32 priority)
{
    struct tipc_bearer *b_ptr;
    struct tipc_media *m_ptr;
    struct tipc_bearer_names b_names;
    char addr_string[16];
    u32 bearer_id;
    u32 with_this_prio;
    u32 i;
    int res = -EINVAL;

    if (!tipc_own_addr) {
        pr_warn("Bearer <%s> rejected, not supported in standalone mode\n",
            name);
        return -ENOPROTOOPT;
    }
    if (!bearer_name_validate(name, &b_names)) {
        pr_warn("Bearer <%s> rejected, illegal name\n", name);
        return -EINVAL;
    }
    if (tipc_addr_domain_valid(disc_domain) &&
        (disc_domain != tipc_own_addr)) {
        if (tipc_in_scope(disc_domain, tipc_own_addr)) {
            disc_domain = tipc_own_addr & TIPC_CLUSTER_MASK;
            res = 0;   /* accept any node in own cluster */
        } else if (in_own_cluster_exact(disc_domain))
            res = 0;   /* accept specified node in own cluster */
    }
    if (res) {
        pr_warn("Bearer <%s> rejected, illegal discovery domain\n",
            name);
        return -EINVAL;
    }
    if ((priority > TIPC_MAX_LINK_PRI) &&
        (priority != TIPC_MEDIA_LINK_PRI)) {
        pr_warn("Bearer <%s> rejected, illegal priority\n", name);
        return -EINVAL;
    }

    write_lock_bh(&tipc_net_lock);

    m_ptr = tipc_media_find(b_names.media_name);
    if (!m_ptr) {
        pr_warn("Bearer <%s> rejected, media <%s> not registered\n",
            name, b_names.media_name);
        goto exit;
    }

    if (priority == TIPC_MEDIA_LINK_PRI)
        priority = m_ptr->priority;

restart:
    bearer_id = MAX_BEARERS;
    with_this_prio = 1;
    for (i = MAX_BEARERS; i-- != 0; ) {
        if (!tipc_bearers[i].active) {
            bearer_id = i;
            continue;
        }
        if (!strcmp(name, tipc_bearers[i].name)) {
            pr_warn("Bearer <%s> rejected, already enabled\n",
                name);
            goto exit;
        }
        if ((tipc_bearers[i].priority == priority) &&
            (++with_this_prio > 2)) {
            if (priority-- == 0) {
                pr_warn("Bearer <%s> rejected, duplicate priority\n",
                    name);
                goto exit;
            }
            pr_warn("Bearer <%s> priority adjustment required %u->%u\n",
                name, priority + 1, priority);
            goto restart;
        }
    }
    if (bearer_id >= MAX_BEARERS) {
        pr_warn("Bearer <%s> rejected, bearer limit reached (%u)\n",
            name, MAX_BEARERS);
        goto exit;
    }

    b_ptr = &tipc_bearers[bearer_id];
    strcpy(b_ptr->name, name);
    res = m_ptr->enable_bearer(b_ptr);
    if (res) {
        pr_warn("Bearer <%s> rejected, enable failure (%d)\n",
            name, -res);
        goto exit;
    }

    b_ptr->identity = bearer_id;
    b_ptr->media = m_ptr;
    b_ptr->tolerance = m_ptr->tolerance;
    b_ptr->window = m_ptr->window;
    b_ptr->net_plane = bearer_id + 'A';
    b_ptr->active = 1;
    b_ptr->priority = priority;
    INIT_LIST_HEAD(&b_ptr->cong_links);
    INIT_LIST_HEAD(&b_ptr->links);
    spin_lock_init(&b_ptr->lock);

    res = tipc_disc_create(b_ptr, &m_ptr->bcast_addr, disc_domain);
    if (res) {
        bearer_disable(b_ptr);
        pr_warn("Bearer <%s> rejected, discovery object creation failed\n",
            name);
        goto exit;
    }
    pr_info("Enabled bearer <%s>, discovery domain %s, priority %u\n",
        name,
        tipc_addr_string_fill(addr_string, disc_domain), priority);
exit:
    write_unlock_bh(&tipc_net_lock);
    return res;
}

int tipc_block_bearer(const char *name)
{
    struct tipc_bearer *b_ptr = NULL;
    struct tipc_link *l_ptr;
    struct tipc_link *temp_l_ptr;

    read_lock_bh(&tipc_net_lock);
    b_ptr = tipc_bearer_find(name);
    if (!b_ptr) {
        pr_warn("Attempt to block unknown bearer <%s>\n", name);
        read_unlock_bh(&tipc_net_lock);
        return -EINVAL;
    }

    pr_info("Blocking bearer <%s>\n", name);
    spin_lock_bh(&b_ptr->lock);
    b_ptr->blocked = 1;
    list_splice_init(&b_ptr->cong_links, &b_ptr->links);
    list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
        struct tipc_node *n_ptr = l_ptr->owner;

        spin_lock_bh(&n_ptr->lock);
        tipc_link_reset(l_ptr);
        spin_unlock_bh(&n_ptr->lock);
    }
    spin_unlock_bh(&b_ptr->lock);
    read_unlock_bh(&tipc_net_lock);
    return 0;
}

static void bearer_disable(struct tipc_bearer *b_ptr)
{
    struct tipc_link *l_ptr;
    struct tipc_link *temp_l_ptr;

    pr_info("Disabling bearer <%s>\n", b_ptr->name);
    spin_lock_bh(&b_ptr->lock);
    b_ptr->blocked = 1;
    b_ptr->media->disable_bearer(b_ptr);
    list_splice_init(&b_ptr->cong_links, &b_ptr->links);
    list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
        tipc_link_delete(l_ptr);
    }
    if (b_ptr->link_req)
        tipc_disc_delete(b_ptr->link_req);
    spin_unlock_bh(&b_ptr->lock);
    memset(b_ptr, 0, sizeof(struct tipc_bearer));
}

int tipc_disable_bearer(const char *name)
{
    struct tipc_bearer *b_ptr;
    int res;

    write_lock_bh(&tipc_net_lock);
    b_ptr = tipc_bearer_find(name);
    if (b_ptr == NULL) {
        pr_warn("Attempt to disable unknown bearer <%s>\n", name);
        res = -EINVAL;
    } else {
        bearer_disable(b_ptr);
        res = 0;
    }
    write_unlock_bh(&tipc_net_lock);
    return res;
}



void tipc_bearer_stop(void)
{
    u32 i;

    for (i = 0; i < MAX_BEARERS; i++) {
        if (tipc_bearers[i].active)
            bearer_disable(&tipc_bearers[i]);
    }
    media_count = 0;
}