/*
 * net/tipc/discover.c
 *
 * Copyright (c) 2003-2006, Ericsson AB
 * Copyright (c) 2005-2006, 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 "link.h"
#include "zone.h"
#include "discover.h"
#include "port.h"
#include "name_table.h"

#define TIPC_LINK_REQ_INIT      125     /* min delay during bearer start up */
#define TIPC_LINK_REQ_FAST      2000    /* normal delay if bearer has no links */
#define TIPC_LINK_REQ_SLOW      600000  /* normal delay if bearer has links */

#if 0
#define  GET_NODE_INFO         300
#define  GET_NODE_INFO_RESULT  301
#define  FORWARD_LINK_PROBE    302
#define  LINK_REQUEST_REJECTED 303
#define  LINK_REQUEST_ACCEPTED 304
#define  DROP_LINK_REQUEST     305
#define  CHECK_LINK_COUNT      306
#endif

/*
 * TODO: Most of the inter-cluster setup stuff should be
 * rewritten, and be made conformant with specification.
 */


/**
 * struct link_req - information about an ongoing link setup request
 * @bearer: bearer issuing requests
 * @dest: destination address for request messages
 * @buf: request message to be (repeatedly) sent
 * @timer: timer governing period between requests
 * @timer_intv: current interval between requests (in ms)
 */
struct link_req {
        struct bearer *bearer;
        struct tipc_media_addr dest;
        struct sk_buff *buf;
        struct timer_list timer;
        unsigned int timer_intv;
};


#if 0
int disc_create_link(const struct tipc_link_create *argv)
{
        /*
         * Code for inter cluster link setup here
         */
        return TIPC_OK;
}
#endif

/*
 * disc_lost_link(): A link has lost contact
 */

void tipc_disc_link_event(u32 addr, char *name, int up)
{
        if (in_own_cluster(addr))
                return;
        /*
         * Code for inter cluster link setup here
         */
}

/**
 * tipc_disc_init_msg - initialize a link setup message
 * @type: message type (request or response)
 * @req_links: number of links associated with message
 * @dest_domain: network domain of node(s) which should respond to message
 * @b_ptr: ptr to bearer issuing message
 */

static struct sk_buff *tipc_disc_init_msg(u32 type,
                                          u32 req_links,
                                          u32 dest_domain,
                                          struct bearer *b_ptr)
{
        struct sk_buff *buf = buf_acquire(DSC_H_SIZE);
        struct tipc_msg *msg;

        if (buf) {
                msg = buf_msg(buf);
                msg_init(msg, LINK_CONFIG, type, DSC_H_SIZE, dest_domain);
                msg_set_non_seq(msg, 1);
                msg_set_req_links(msg, req_links);
                msg_set_dest_domain(msg, dest_domain);
                msg_set_bc_netid(msg, tipc_net_id);
                msg_set_media_addr(msg, &b_ptr->publ.addr);
        }
        return buf;
}

/**
 * disc_dupl_alert - issue node address duplication alert
 * @b_ptr: pointer to bearer detecting duplication
 * @node_addr: duplicated node address
 * @media_addr: media address advertised by duplicated node
 */

static void disc_dupl_alert(struct bearer *b_ptr, u32 node_addr,
                            struct tipc_media_addr *media_addr)
{
        char node_addr_str[16];
        char media_addr_str[64];
        struct print_buf pb;

        addr_string_fill(node_addr_str, node_addr);
        tipc_printbuf_init(&pb, media_addr_str, sizeof(media_addr_str));
        tipc_media_addr_printf(&pb, media_addr);
        tipc_printbuf_validate(&pb);
        warn("Duplicate %s using %s seen on <%s>\n",
             node_addr_str, media_addr_str, b_ptr->publ.name);
}

/**
 * tipc_disc_recv_msg - handle incoming link setup message (request or response)
 * @buf: buffer containing message
 * @b_ptr: bearer that message arrived on
 */

void tipc_disc_recv_msg(struct sk_buff *buf, struct bearer *b_ptr)
{
        struct link *link;
        struct tipc_media_addr media_addr;
        struct tipc_msg *msg = buf_msg(buf);
        u32 dest = msg_dest_domain(msg);
        u32 orig = msg_prevnode(msg);
        u32 net_id = msg_bc_netid(msg);
        u32 type = msg_type(msg);

        msg_get_media_addr(msg,&media_addr);
        msg_dbg(msg, "RECV:");
        buf_discard(buf);

        if (net_id != tipc_net_id)
                return;
        if (!tipc_addr_domain_valid(dest))
                return;
        if (!tipc_addr_node_valid(orig))
                return;
        if (orig == tipc_own_addr) {
                if (memcmp(&media_addr, &b_ptr->publ.addr, sizeof(media_addr)))
                        disc_dupl_alert(b_ptr, tipc_own_addr, &media_addr);
                return;
        }
        if (!in_scope(dest, tipc_own_addr))
                return;
        if (is_slave(tipc_own_addr) && is_slave(orig))
                return;
        if (is_slave(orig) && !in_own_cluster(orig))
                return;
        if (in_own_cluster(orig)) {
                /* Always accept link here */
                struct sk_buff *rbuf;
                struct tipc_media_addr *addr;
                struct tipc_node *n_ptr = tipc_node_find(orig);
                int link_fully_up;

                dbg(" in own cluster\n");
                if (n_ptr == NULL) {
                        n_ptr = tipc_node_create(orig);
                        if (!n_ptr)
                                return;
                }
                spin_lock_bh(&n_ptr->lock);
                link = n_ptr->links[b_ptr->identity];
                if (!link) {
                        dbg("creating link\n");
                        link = tipc_link_create(b_ptr, orig, &media_addr);
                        if (!link) {
                                spin_unlock_bh(&n_ptr->lock);
                                return;
                        }
                }
                addr = &link->media_addr;
                if (memcmp(addr, &media_addr, sizeof(*addr))) {
                        if (tipc_link_is_up(link) || (!link->started)) {
                                disc_dupl_alert(b_ptr, orig, &media_addr);
                                spin_unlock_bh(&n_ptr->lock);
                                return;
                        }
                        warn("Resetting link <%s>, peer interface address changed\n",
                             link->name);
                        memcpy(addr, &media_addr, sizeof(*addr));
                        tipc_link_reset(link);
                }
                link_fully_up = (link->state == WORKING_WORKING);
                spin_unlock_bh(&n_ptr->lock);
                if ((type == DSC_RESP_MSG) || link_fully_up)
                        return;
                rbuf = tipc_disc_init_msg(DSC_RESP_MSG, 1, orig, b_ptr);
                if (rbuf != NULL) {
                        msg_dbg(buf_msg(rbuf),"SEND:");
                        b_ptr->media->send_msg(rbuf, &b_ptr->publ, &media_addr);
                        buf_discard(rbuf);
                }
        }
}

/**
 * tipc_disc_stop_link_req - stop sending periodic link setup requests
 * @req: ptr to link request structure
 */

void tipc_disc_stop_link_req(struct link_req *req)
{
        if (!req)
                return;

        k_cancel_timer(&req->timer);
        k_term_timer(&req->timer);
        buf_discard(req->buf);
        kfree(req);
}

/**
 * tipc_disc_update_link_req - update frequency of periodic link setup requests
 * @req: ptr to link request structure
 */

void tipc_disc_update_link_req(struct link_req *req)
{
        if (!req)
                return;

        if (req->timer_intv == TIPC_LINK_REQ_SLOW) {
                if (!req->bearer->nodes.count) {
                        req->timer_intv = TIPC_LINK_REQ_FAST;
                        k_start_timer(&req->timer, req->timer_intv);
                }
        } else if (req->timer_intv == TIPC_LINK_REQ_FAST) {
                if (req->bearer->nodes.count) {
                        req->timer_intv = TIPC_LINK_REQ_SLOW;
                        k_start_timer(&req->timer, req->timer_intv);
                }
        } else {
                /* leave timer "as is" if haven't yet reached a "normal" rate */
        }
}

/**
 * disc_timeout - send a periodic link setup request
 * @req: ptr to link request structure
 *
 * Called whenever a link setup request timer associated with a bearer expires.
 */

static void disc_timeout(struct link_req *req)
{
        spin_lock_bh(&req->bearer->publ.lock);

        req->bearer->media->send_msg(req->buf, &req->bearer->publ, &req->dest);

        if ((req->timer_intv == TIPC_LINK_REQ_SLOW) ||
            (req->timer_intv == TIPC_LINK_REQ_FAST)) {
                /* leave timer interval "as is" if already at a "normal" rate */
        } else {
                req->timer_intv *= 2;
                if (req->timer_intv > TIPC_LINK_REQ_FAST)
                        req->timer_intv = TIPC_LINK_REQ_FAST;
                if ((req->timer_intv == TIPC_LINK_REQ_FAST) &&
                    (req->bearer->nodes.count))
                        req->timer_intv = TIPC_LINK_REQ_SLOW;
        }
        k_start_timer(&req->timer, req->timer_intv);

        spin_unlock_bh(&req->bearer->publ.lock);
}

/**
 * tipc_disc_init_link_req - start sending periodic link setup requests
 * @b_ptr: ptr to bearer issuing requests
 * @dest: destination address for request messages
 * @dest_domain: network domain of node(s) which should respond to message
 * @req_links: max number of desired links
 *
 * Returns pointer to link request structure, or NULL if unable to create.
 */

struct link_req *tipc_disc_init_link_req(struct bearer *b_ptr,
                                         const struct tipc_media_addr *dest,
                                         u32 dest_domain,
                                         u32 req_links)
{
        struct link_req *req;

        req = kmalloc(sizeof(*req), GFP_ATOMIC);
        if (!req)
                return NULL;

        req->buf = tipc_disc_init_msg(DSC_REQ_MSG, req_links, dest_domain, b_ptr);
        if (!req->buf) {
                kfree(req);
                return NULL;
        }

        memcpy(&req->dest, dest, sizeof(*dest));
        req->bearer = b_ptr;
        req->timer_intv = TIPC_LINK_REQ_INIT;
        k_init_timer(&req->timer, (Handler)disc_timeout, (unsigned long)req);
        k_start_timer(&req->timer, req->timer_intv);
        return req;
}