writeback: split writeback_inodes_wb

[linux-2.6/next.git] / net / tipc / config.c

/*
 * net/tipc/config.c: TIPC configuration management code
 *
 * Copyright (c) 2002-2006, Ericsson AB
 * Copyright (c) 2004-2007, 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 "dbg.h"
#include "bearer.h"
#include "port.h"
#include "link.h"
#include "zone.h"
#include "addr.h"
#include "name_table.h"
#include "node.h"
#include "config.h"
#include "discover.h"

struct subscr_data {
        char usr_handle[8];
        u32 domain;
        u32 port_ref;
        struct list_head subd_list;
};

struct manager {
        u32 user_ref;
        u32 port_ref;
};

static struct manager mng = { 0};

static DEFINE_SPINLOCK(config_lock);

static const void *req_tlv_area;        /* request message TLV area */
static int req_tlv_space;               /* request message TLV area size */
static int rep_headroom;                /* reply message headroom to use */


struct sk_buff *tipc_cfg_reply_alloc(int payload_size)
{
        struct sk_buff *buf;

        buf = alloc_skb(rep_headroom + payload_size, GFP_ATOMIC);
        if (buf)
                skb_reserve(buf, rep_headroom);
        return buf;
}

int tipc_cfg_append_tlv(struct sk_buff *buf, int tlv_type,
                        void *tlv_data, int tlv_data_size)
{
        struct tlv_desc *tlv = (struct tlv_desc *)skb_tail_pointer(buf);
        int new_tlv_space = TLV_SPACE(tlv_data_size);

        if (skb_tailroom(buf) < new_tlv_space) {
                dbg("tipc_cfg_append_tlv unable to append TLV\n");
                return 0;
        }
        skb_put(buf, new_tlv_space);
        tlv->tlv_type = htons(tlv_type);
        tlv->tlv_len  = htons(TLV_LENGTH(tlv_data_size));
        if (tlv_data_size && tlv_data)
                memcpy(TLV_DATA(tlv), tlv_data, tlv_data_size);
        return 1;
}

struct sk_buff *tipc_cfg_reply_unsigned_type(u16 tlv_type, u32 value)
{
        struct sk_buff *buf;
        __be32 value_net;

        buf = tipc_cfg_reply_alloc(TLV_SPACE(sizeof(value)));
        if (buf) {
                value_net = htonl(value);
                tipc_cfg_append_tlv(buf, tlv_type, &value_net,
                                    sizeof(value_net));
        }
        return buf;
}

struct sk_buff *tipc_cfg_reply_string_type(u16 tlv_type, char *string)
{
        struct sk_buff *buf;
        int string_len = strlen(string) + 1;

        buf = tipc_cfg_reply_alloc(TLV_SPACE(string_len));
        if (buf)
                tipc_cfg_append_tlv(buf, tlv_type, string, string_len);
        return buf;
}


#if 0

/* Now obsolete code for handling commands not yet implemented the new way */

/*
 * Some of this code assumed that the manager structure contains two added
 * fields:
 *      u32 link_subscriptions;
 *      struct list_head link_subscribers;
 * which are currently not present.  These fields may need to be re-introduced
 * if and when support for link subscriptions is added.
 */

void tipc_cfg_link_event(u32 addr, char *name, int up)
{
        /* TIPC DOESN'T HANDLE LINK EVENT SUBSCRIPTIONS AT THE MOMENT */
}

int tipc_cfg_cmd(const struct tipc_cmd_msg * msg,
                 char *data,
                 u32 sz,
                 u32 *ret_size,
                 struct tipc_portid *orig)
{
        int rv = -EINVAL;
        u32 cmd = msg->cmd;

        *ret_size = 0;
        switch (cmd) {
        case TIPC_REMOVE_LINK:
        case TIPC_CMD_BLOCK_LINK:
        case TIPC_CMD_UNBLOCK_LINK:
                if (!cfg_check_connection(orig))
                        rv = link_control(msg->argv.link_name, msg->cmd, 0);
                break;
        case TIPC_ESTABLISH:
                {
                        int connected;

                        tipc_isconnected(mng.conn_port_ref, &connected);
                        if (connected || !orig) {
                                rv = TIPC_FAILURE;
                                break;
                        }
                        rv = tipc_connect2port(mng.conn_port_ref, orig);
                        if (rv == TIPC_OK)
                                orig = 0;
                        break;
                }
        case TIPC_GET_PEER_ADDRESS:
                *ret_size = link_peer_addr(msg->argv.link_name, data, sz);
                break;
        case TIPC_GET_ROUTES:
                rv = TIPC_OK;
                break;
        default: {}
        }
        if (*ret_size)
                rv = TIPC_OK;
        return rv;
}

static void cfg_cmd_event(struct tipc_cmd_msg *msg,
                          char *data,
                          u32 sz,
                          struct tipc_portid const *orig)
{
        int rv = -EINVAL;
        struct tipc_cmd_result_msg rmsg;
        struct iovec msg_sect[2];
        int *arg;

        msg->cmd = ntohl(msg->cmd);

        cfg_prepare_res_msg(msg->cmd, msg->usr_handle, rv, &rmsg, msg_sect,
                            data, 0);
        if (ntohl(msg->magic) != TIPC_MAGIC)
                goto exit;

        switch (msg->cmd) {
        case TIPC_CREATE_LINK:
                if (!cfg_check_connection(orig))
                        rv = disc_create_link(&msg->argv.create_link);
                break;
        case TIPC_LINK_SUBSCRIBE:
                {
                        struct subscr_data *sub;

                        if (mng.link_subscriptions > 64)
                                break;
                        sub = kmalloc(sizeof(*sub),
                                                            GFP_ATOMIC);
                        if (sub == NULL) {
                                warn("Memory squeeze; dropped remote link subscription\n");
                                break;
                        }
                        INIT_LIST_HEAD(&sub->subd_list);
                        tipc_createport(mng.user_ref,
                                        (void *)sub,
                                        TIPC_HIGH_IMPORTANCE,
                                        0,
                                        0,
                                        (tipc_conn_shutdown_event)cfg_linksubscr_cancel,
                                        0,
                                        0,
                                        (tipc_conn_msg_event)cfg_linksubscr_cancel,
                                        0,
                                        &sub->port_ref);
                        if (!sub->port_ref) {
                                kfree(sub);
                                break;
                        }
                        memcpy(sub->usr_handle,msg->usr_handle,
                               sizeof(sub->usr_handle));
                        sub->domain = msg->argv.domain;
                        list_add_tail(&sub->subd_list, &mng.link_subscribers);
                        tipc_connect2port(sub->port_ref, orig);
                        rmsg.retval = TIPC_OK;
                        tipc_send(sub->port_ref, 2u, msg_sect);
                        mng.link_subscriptions++;
                        return;
                }
        default:
                rv = tipc_cfg_cmd(msg, data, sz, (u32 *)&msg_sect[1].iov_len, orig);
        }
exit:
        rmsg.result_len = htonl(msg_sect[1].iov_len);
        rmsg.retval = htonl(rv);
        tipc_cfg_respond(msg_sect, 2u, orig);
}
#endif

#define MAX_STATS_INFO 2000

static struct sk_buff *tipc_show_stats(void)
{
        struct sk_buff *buf;
        struct tlv_desc *rep_tlv;
        struct print_buf pb;
        int str_len;
        u32 value;

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

        value = ntohl(*(u32 *)TLV_DATA(req_tlv_area));
        if (value != 0)
                return tipc_cfg_reply_error_string("unsupported argument");

        buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_STATS_INFO));
        if (buf == NULL)
                return NULL;

        rep_tlv = (struct tlv_desc *)buf->data;
        tipc_printbuf_init(&pb, (char *)TLV_DATA(rep_tlv), MAX_STATS_INFO);

        tipc_printf(&pb, "TIPC version " TIPC_MOD_VER "\n");

        /* Use additional tipc_printf()'s to return more info ... */

        str_len = tipc_printbuf_validate(&pb);
        skb_put(buf, TLV_SPACE(str_len));
        TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);

        return buf;
}

static struct sk_buff *cfg_enable_bearer(void)
{
        struct tipc_bearer_config *args;

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

        args = (struct tipc_bearer_config *)TLV_DATA(req_tlv_area);
        if (tipc_enable_bearer(args->name,
                               ntohl(args->detect_scope),
                               ntohl(args->priority)))
                return tipc_cfg_reply_error_string("unable to enable bearer");

        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_disable_bearer(void)
{
        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_BEARER_NAME))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

        if (tipc_disable_bearer((char *)TLV_DATA(req_tlv_area)))
                return tipc_cfg_reply_error_string("unable to disable bearer");

        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_own_addr(void)
{
        u32 addr;

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

        addr = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (addr == tipc_own_addr)
                return tipc_cfg_reply_none();
        if (!tipc_addr_node_valid(addr))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (node address)");
        if (tipc_mode == TIPC_NET_MODE)
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                                                   " (cannot change node address once assigned)");

        /*
         * Must release all spinlocks before calling start_net() because
         * Linux version of TIPC calls eth_media_start() which calls
         * register_netdevice_notifier() which may block!
         *
         * Temporarily releasing the lock should be harmless for non-Linux TIPC,
         * but Linux version of eth_media_start() should really be reworked
         * so that it can be called with spinlocks held.
         */

        spin_unlock_bh(&config_lock);
        tipc_core_start_net(addr);
        spin_lock_bh(&config_lock);
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_remote_mng(void)
{
        u32 value;

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

        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        tipc_remote_management = (value != 0);
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_max_publications(void)
{
        u32 value;

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

        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value != delimit(value, 1, 65535))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (max publications must be 1-65535)");
        tipc_max_publications = value;
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_max_subscriptions(void)
{
        u32 value;

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

        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value != delimit(value, 1, 65535))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (max subscriptions must be 1-65535");
        tipc_max_subscriptions = value;
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_max_ports(void)
{
        u32 value;

        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value == tipc_max_ports)
                return tipc_cfg_reply_none();
        if (value != delimit(value, 127, 65535))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (max ports must be 127-65535)");
        if (tipc_mode != TIPC_NOT_RUNNING)
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                        " (cannot change max ports while TIPC is active)");
        tipc_max_ports = value;
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_max_zones(void)
{
        u32 value;

        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value == tipc_max_zones)
                return tipc_cfg_reply_none();
        if (value != delimit(value, 1, 255))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (max zones must be 1-255)");
        if (tipc_mode == TIPC_NET_MODE)
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                        " (cannot change max zones once TIPC has joined a network)");
        tipc_max_zones = value;
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_max_clusters(void)
{
        u32 value;

        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value != delimit(value, 1, 1))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (max clusters fixed at 1)");
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_max_nodes(void)
{
        u32 value;

        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value == tipc_max_nodes)
                return tipc_cfg_reply_none();
        if (value != delimit(value, 8, 2047))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (max nodes must be 8-2047)");
        if (tipc_mode == TIPC_NET_MODE)
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                        " (cannot change max nodes once TIPC has joined a network)");
        tipc_max_nodes = value;
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_max_slaves(void)
{
        u32 value;

        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value != 0)
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                                                   " (max secondary nodes fixed at 0)");
        return tipc_cfg_reply_none();
}

static struct sk_buff *cfg_set_netid(void)
{
        u32 value;

        if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_UNSIGNED))
                return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
        value = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (value == tipc_net_id)
                return tipc_cfg_reply_none();
        if (value != delimit(value, 1, 9999))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (network id must be 1-9999)");
        if (tipc_mode == TIPC_NET_MODE)
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                        " (cannot change network id once TIPC has joined a network)");
        tipc_net_id = value;
        return tipc_cfg_reply_none();
}

struct sk_buff *tipc_cfg_do_cmd(u32 orig_node, u16 cmd, const void *request_area,
                                int request_space, int reply_headroom)
{
        struct sk_buff *rep_tlv_buf;

        spin_lock_bh(&config_lock);

        /* Save request and reply details in a well-known location */

        req_tlv_area = request_area;
        req_tlv_space = request_space;
        rep_headroom = reply_headroom;

        /* Check command authorization */

        if (likely(orig_node == tipc_own_addr)) {
                /* command is permitted */
        } else if (cmd >= 0x8000) {
                rep_tlv_buf = tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                                                          " (cannot be done remotely)");
                goto exit;
        } else if (!tipc_remote_management) {
                rep_tlv_buf = tipc_cfg_reply_error_string(TIPC_CFG_NO_REMOTE);
                goto exit;
        }
        else if (cmd >= 0x4000) {
                u32 domain = 0;

                if ((tipc_nametbl_translate(TIPC_ZM_SRV, 0, &domain) == 0) ||
                    (domain != orig_node)) {
                        rep_tlv_buf = tipc_cfg_reply_error_string(TIPC_CFG_NOT_ZONE_MSTR);
                        goto exit;
                }
        }

        /* Call appropriate processing routine */

        switch (cmd) {
        case TIPC_CMD_NOOP:
                rep_tlv_buf = tipc_cfg_reply_none();
                break;
        case TIPC_CMD_GET_NODES:
                rep_tlv_buf = tipc_node_get_nodes(req_tlv_area, req_tlv_space);
                break;
        case TIPC_CMD_GET_LINKS:
                rep_tlv_buf = tipc_node_get_links(req_tlv_area, req_tlv_space);
                break;
        case TIPC_CMD_SHOW_LINK_STATS:
                rep_tlv_buf = tipc_link_cmd_show_stats(req_tlv_area, req_tlv_space);
                break;
        case TIPC_CMD_RESET_LINK_STATS:
                rep_tlv_buf = tipc_link_cmd_reset_stats(req_tlv_area, req_tlv_space);
                break;
        case TIPC_CMD_SHOW_NAME_TABLE:
                rep_tlv_buf = tipc_nametbl_get(req_tlv_area, req_tlv_space);
                break;
        case TIPC_CMD_GET_BEARER_NAMES:
                rep_tlv_buf = tipc_bearer_get_names();
                break;
        case TIPC_CMD_GET_MEDIA_NAMES:
                rep_tlv_buf = tipc_media_get_names();
                break;
        case TIPC_CMD_SHOW_PORTS:
                rep_tlv_buf = tipc_port_get_ports();
                break;
#if 0
        case TIPC_CMD_SHOW_PORT_STATS:
                rep_tlv_buf = port_show_stats(req_tlv_area, req_tlv_space);
                break;
        case TIPC_CMD_RESET_PORT_STATS:
                rep_tlv_buf = tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED);
                break;
#endif
        case TIPC_CMD_SET_LOG_SIZE:
                rep_tlv_buf = tipc_log_resize_cmd(req_tlv_area, req_tlv_space);
                break;
        case TIPC_CMD_DUMP_LOG:
                rep_tlv_buf = tipc_log_dump();
                break;
        case TIPC_CMD_SHOW_STATS:
                rep_tlv_buf = tipc_show_stats();
                break;
        case TIPC_CMD_SET_LINK_TOL:
        case TIPC_CMD_SET_LINK_PRI:
        case TIPC_CMD_SET_LINK_WINDOW:
                rep_tlv_buf = tipc_link_cmd_config(req_tlv_area, req_tlv_space, cmd);
                break;
        case TIPC_CMD_ENABLE_BEARER:
                rep_tlv_buf = cfg_enable_bearer();
                break;
        case TIPC_CMD_DISABLE_BEARER:
                rep_tlv_buf = cfg_disable_bearer();
                break;
        case TIPC_CMD_SET_NODE_ADDR:
                rep_tlv_buf = cfg_set_own_addr();
                break;
        case TIPC_CMD_SET_REMOTE_MNG:
                rep_tlv_buf = cfg_set_remote_mng();
                break;
        case TIPC_CMD_SET_MAX_PORTS:
                rep_tlv_buf = cfg_set_max_ports();
                break;
        case TIPC_CMD_SET_MAX_PUBL:
                rep_tlv_buf = cfg_set_max_publications();
                break;
        case TIPC_CMD_SET_MAX_SUBSCR:
                rep_tlv_buf = cfg_set_max_subscriptions();
                break;
        case TIPC_CMD_SET_MAX_ZONES:
                rep_tlv_buf = cfg_set_max_zones();
                break;
        case TIPC_CMD_SET_MAX_CLUSTERS:
                rep_tlv_buf = cfg_set_max_clusters();
                break;
        case TIPC_CMD_SET_MAX_NODES:
                rep_tlv_buf = cfg_set_max_nodes();
                break;
        case TIPC_CMD_SET_MAX_SLAVES:
                rep_tlv_buf = cfg_set_max_slaves();
                break;
        case TIPC_CMD_SET_NETID:
                rep_tlv_buf = cfg_set_netid();
                break;
        case TIPC_CMD_GET_REMOTE_MNG:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_remote_management);
                break;
        case TIPC_CMD_GET_MAX_PORTS:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_max_ports);
                break;
        case TIPC_CMD_GET_MAX_PUBL:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_max_publications);
                break;
        case TIPC_CMD_GET_MAX_SUBSCR:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_max_subscriptions);
                break;
        case TIPC_CMD_GET_MAX_ZONES:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_max_zones);
                break;
        case TIPC_CMD_GET_MAX_CLUSTERS:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_max_clusters);
                break;
        case TIPC_CMD_GET_MAX_NODES:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_max_nodes);
                break;
        case TIPC_CMD_GET_MAX_SLAVES:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_max_slaves);
                break;
        case TIPC_CMD_GET_NETID:
                rep_tlv_buf = tipc_cfg_reply_unsigned(tipc_net_id);
                break;
        case TIPC_CMD_NOT_NET_ADMIN:
                rep_tlv_buf =
                        tipc_cfg_reply_error_string(TIPC_CFG_NOT_NET_ADMIN);
                break;
        default:
                rep_tlv_buf = tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                                                          " (unknown command)");
                break;
        }

        /* Return reply buffer */
exit:
        spin_unlock_bh(&config_lock);
        return rep_tlv_buf;
}

static void cfg_named_msg_event(void *userdata,
                                u32 port_ref,
                                struct sk_buff **buf,
                                const unchar *msg,
                                u32 size,
                                u32 importance,
                                struct tipc_portid const *orig,
                                struct tipc_name_seq const *dest)
{
        struct tipc_cfg_msg_hdr *req_hdr;
        struct tipc_cfg_msg_hdr *rep_hdr;
        struct sk_buff *rep_buf;

        /* Validate configuration message header (ignore invalid message) */

        req_hdr = (struct tipc_cfg_msg_hdr *)msg;
        if ((size < sizeof(*req_hdr)) ||
            (size != TCM_ALIGN(ntohl(req_hdr->tcm_len))) ||
            (ntohs(req_hdr->tcm_flags) != TCM_F_REQUEST)) {
                warn("Invalid configuration message discarded\n");
                return;
        }

        /* Generate reply for request (if can't, return request) */

        rep_buf = tipc_cfg_do_cmd(orig->node,
                                  ntohs(req_hdr->tcm_type),
                                  msg + sizeof(*req_hdr),
                                  size - sizeof(*req_hdr),
                                  BUF_HEADROOM + MAX_H_SIZE + sizeof(*rep_hdr));
        if (rep_buf) {
                skb_push(rep_buf, sizeof(*rep_hdr));
                rep_hdr = (struct tipc_cfg_msg_hdr *)rep_buf->data;
                memcpy(rep_hdr, req_hdr, sizeof(*rep_hdr));
                rep_hdr->tcm_len = htonl(rep_buf->len);
                rep_hdr->tcm_flags &= htons(~TCM_F_REQUEST);
        } else {
                rep_buf = *buf;
                *buf = NULL;
        }

        /* NEED TO ADD CODE TO HANDLE FAILED SEND (SUCH AS CONGESTION) */
        tipc_send_buf2port(port_ref, orig, rep_buf, rep_buf->len);
}

int tipc_cfg_init(void)
{
        struct tipc_name_seq seq;
        int res;

        res = tipc_attach(&mng.user_ref, NULL, NULL);
        if (res)
                goto failed;

        res = tipc_createport(mng.user_ref, NULL, TIPC_CRITICAL_IMPORTANCE,
                              NULL, NULL, NULL,
                              NULL, cfg_named_msg_event, NULL,
                              NULL, &mng.port_ref);
        if (res)
                goto failed;

        seq.type = TIPC_CFG_SRV;
        seq.lower = seq.upper = tipc_own_addr;
        res = tipc_nametbl_publish_rsv(mng.port_ref, TIPC_ZONE_SCOPE, &seq);
        if (res)
                goto failed;

        return 0;

failed:
        err("Unable to create configuration service\n");
        tipc_detach(mng.user_ref);
        mng.user_ref = 0;
        return res;
}

void tipc_cfg_stop(void)
{
        if (mng.user_ref) {
                tipc_detach(mng.user_ref);
                mng.user_ref = 0;
        }
}