/*
 * net/tipc/bcast.c: TIPC broadcast code
 *
 * Copyright (c) 2004-2006, 2014-2015, Ericsson AB
 * Copyright (c) 2004, Intel Corporation.
 * Copyright (c) 2005, 2010-2011, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/tipc_config.h>
#include "socket.h"
#include "msg.h"
#include "bcast.h"
#include "name_distr.h"
#include "link.h"
#include "node.h"

#define BCLINK_WIN_DEFAULT      50      /* bcast link window size (default) */
#define BCLINK_WIN_MIN          32      /* bcast minimum link window size */

const char tipc_bclink_name[] = "broadcast-link";

/**
 * struct tipc_bc_base - base structure for keeping broadcast send state
 * @link: broadcast send link structure
 * @inputq: data input queue; will only carry SOCK_WAKEUP messages
 * @dest: array keeping number of reachable destinations per bearer
 * @primary_bearer: a bearer having links to all broadcast destinations, if any
 */
struct tipc_bc_base {
        struct tipc_link *link;
        struct sk_buff_head inputq;
        int dests[MAX_BEARERS];
        int primary_bearer;
};

static struct tipc_bc_base *tipc_bc_base(struct net *net)
{
        return tipc_net(net)->bcbase;
}

int tipc_bcast_get_mtu(struct net *net)
{
        return tipc_link_mtu(tipc_bc_sndlink(net));
}

/* tipc_bcbase_select_primary(): find a bearer with links to all destinations,
 *                               if any, and make it primary bearer
 */
static void tipc_bcbase_select_primary(struct net *net)
{
        struct tipc_bc_base *bb = tipc_bc_base(net);
        int all_dests =  tipc_link_bc_peers(bb->link);
        int i, mtu;

        bb->primary_bearer = INVALID_BEARER_ID;

        if (!all_dests)
                return;

        for (i = 0; i < MAX_BEARERS; i++) {
                if (!bb->dests[i])
                        continue;

                mtu = tipc_bearer_mtu(net, i);
                if (mtu < tipc_link_mtu(bb->link))
                        tipc_link_set_mtu(bb->link, mtu);

                if (bb->dests[i] < all_dests)
                        continue;

                bb->primary_bearer = i;

                /* Reduce risk that all nodes select same primary */
                if ((i ^ tipc_own_addr(net)) & 1)
                        break;
        }
}

void tipc_bcast_inc_bearer_dst_cnt(struct net *net, int bearer_id)
{
        struct tipc_bc_base *bb = tipc_bc_base(net);

        tipc_bcast_lock(net);
        bb->dests[bearer_id]++;
        tipc_bcbase_select_primary(net);
        tipc_bcast_unlock(net);
}

void tipc_bcast_dec_bearer_dst_cnt(struct net *net, int bearer_id)
{
        struct tipc_bc_base *bb = tipc_bc_base(net);

        tipc_bcast_lock(net);
        bb->dests[bearer_id]--;
        tipc_bcbase_select_primary(net);
        tipc_bcast_unlock(net);
}

/* tipc_bcbase_xmit - broadcast a packet queue across one or more bearers
 *
 * Note that number of reachable destinations, as indicated in the dests[]
 * array, may transitionally differ from the number of destinations indicated
 * in each sent buffer. We can sustain this. Excess destination nodes will
 * drop and never acknowledge the unexpected packets, and missing destinations
 * will either require retransmission (if they are just about to be added to
 * the bearer), or be removed from the buffer's 'ackers' counter (if they
 * just went down)
 */
static void tipc_bcbase_xmit(struct net *net, struct sk_buff_head *xmitq)
{
        int bearer_id;
        struct tipc_bc_base *bb = tipc_bc_base(net);
        struct sk_buff *skb, *_skb;
        struct sk_buff_head _xmitq;

        if (skb_queue_empty(xmitq))
                return;

        /* The typical case: at least one bearer has links to all nodes */
        bearer_id = bb->primary_bearer;
        if (bearer_id >= 0) {
                tipc_bearer_bc_xmit(net, bearer_id, xmitq);
                return;
        }

        /* We have to transmit across all bearers */
        skb_queue_head_init(&_xmitq);
        for (bearer_id = 0; bearer_id < MAX_BEARERS; bearer_id++) {
                if (!bb->dests[bearer_id])
                        continue;

                skb_queue_walk(xmitq, skb) {
                        _skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
                        if (!_skb)
                                break;
                        __skb_queue_tail(&_xmitq, _skb);
                }
                tipc_bearer_bc_xmit(net, bearer_id, &_xmitq);
        }
        __skb_queue_purge(xmitq);
        __skb_queue_purge(&_xmitq);
}

/* tipc_bcast_xmit - deliver buffer chain to all nodes in cluster
 *                    and to identified node local sockets
 * @net: the applicable net namespace
 * @list: chain of buffers containing message
 * Consumes the buffer chain, except when returning -ELINKCONG
 * Returns 0 if success, otherwise errno: -ELINKCONG,-EHOSTUNREACH,-EMSGSIZE
 */
int tipc_bcast_xmit(struct net *net, struct sk_buff_head *list)
{
        struct tipc_link *l = tipc_bc_sndlink(net);
        struct sk_buff_head xmitq, inputq, rcvq;
        int rc = 0;

        __skb_queue_head_init(&rcvq);
        __skb_queue_head_init(&xmitq);
        skb_queue_head_init(&inputq);

        /* Prepare message clone for local node */
        if (unlikely(!tipc_msg_reassemble(list, &rcvq)))
                return -EHOSTUNREACH;

        tipc_bcast_lock(net);
        if (tipc_link_bc_peers(l))
                rc = tipc_link_xmit(l, list, &xmitq);
        tipc_bcast_unlock(net);

        /* Don't send to local node if adding to link failed */
        if (unlikely(rc)) {
                __skb_queue_purge(&rcvq);
                return rc;
        }

        /* Broadcast to all nodes, inluding local node */
        tipc_bcbase_xmit(net, &xmitq);
        tipc_sk_mcast_rcv(net, &rcvq, &inputq);
        __skb_queue_purge(list);
        return 0;
}

/* tipc_bcast_rcv - receive a broadcast packet, and deliver to rcv link
 *
 * RCU is locked, no other locks set
 */
int tipc_bcast_rcv(struct net *net, struct tipc_link *l, struct sk_buff *skb)
{
        struct tipc_msg *hdr = buf_msg(skb);
        struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
        struct sk_buff_head xmitq;
        int rc;

        __skb_queue_head_init(&xmitq);

        if (msg_mc_netid(hdr) != tipc_netid(net) || !tipc_link_is_up(l)) {
                kfree_skb(skb);
                return 0;
        }

        tipc_bcast_lock(net);
        if (msg_user(hdr) == BCAST_PROTOCOL)
                rc = tipc_link_bc_nack_rcv(l, skb, &xmitq);
        else
                rc = tipc_link_rcv(l, skb, NULL);
        tipc_bcast_unlock(net);

        tipc_bcbase_xmit(net, &xmitq);

        /* Any socket wakeup messages ? */
        if (!skb_queue_empty(inputq))
                tipc_sk_rcv(net, inputq);

        return rc;
}

/* tipc_bcast_ack_rcv - receive and handle a broadcast acknowledge
 *
 * RCU is locked, no other locks set
 */
void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l,
                        struct tipc_msg *hdr)
{
        struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
        u16 acked = msg_bcast_ack(hdr);
        struct sk_buff_head xmitq;

        /* Ignore bc acks sent by peer before bcast synch point was received */
        if (msg_bc_ack_invalid(hdr))
                return;

        __skb_queue_head_init(&xmitq);

        tipc_bcast_lock(net);
        tipc_link_bc_ack_rcv(l, acked, &xmitq);
        tipc_bcast_unlock(net);

        tipc_bcbase_xmit(net, &xmitq);

        /* Any socket wakeup messages ? */
        if (!skb_queue_empty(inputq))
                tipc_sk_rcv(net, inputq);
}

/* tipc_bcast_synch_rcv -  check and update rcv link with peer's send state
 *
 * RCU is locked, no other locks set
 */
int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
                        struct tipc_msg *hdr)
{
        struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
        struct sk_buff_head xmitq;
        int rc = 0;

        __skb_queue_head_init(&xmitq);

        tipc_bcast_lock(net);
        if (msg_type(hdr) != STATE_MSG) {
                tipc_link_bc_init_rcv(l, hdr);
        } else if (!msg_bc_ack_invalid(hdr)) {
                tipc_link_bc_ack_rcv(l, msg_bcast_ack(hdr), &xmitq);
                rc = tipc_link_bc_sync_rcv(l, hdr, &xmitq);
        }
        tipc_bcast_unlock(net);

        tipc_bcbase_xmit(net, &xmitq);

        /* Any socket wakeup messages ? */
        if (!skb_queue_empty(inputq))
                tipc_sk_rcv(net, inputq);
        return rc;
}

/* tipc_bcast_add_peer - add a peer node to broadcast link and bearer
 *
 * RCU is locked, node lock is set
 */
void tipc_bcast_add_peer(struct net *net, struct tipc_link *uc_l,
                         struct sk_buff_head *xmitq)
{
        struct tipc_link *snd_l = tipc_bc_sndlink(net);

        tipc_bcast_lock(net);
        tipc_link_add_bc_peer(snd_l, uc_l, xmitq);
        tipc_bcbase_select_primary(net);
        tipc_bcast_unlock(net);
}

/* tipc_bcast_remove_peer - remove a peer node from broadcast link and bearer
 *
 * RCU is locked, node lock is set
 */
void tipc_bcast_remove_peer(struct net *net, struct tipc_link *rcv_l)
{
        struct tipc_link *snd_l = tipc_bc_sndlink(net);
        struct sk_buff_head *inputq = &tipc_bc_base(net)->inputq;
        struct sk_buff_head xmitq;

        __skb_queue_head_init(&xmitq);

        tipc_bcast_lock(net);
        tipc_link_remove_bc_peer(snd_l, rcv_l, &xmitq);
        tipc_bcbase_select_primary(net);
        tipc_bcast_unlock(net);

        tipc_bcbase_xmit(net, &xmitq);

        /* Any socket wakeup messages ? */
        if (!skb_queue_empty(inputq))
                tipc_sk_rcv(net, inputq);
}

int tipc_bclink_reset_stats(struct net *net)
{
        struct tipc_link *l = tipc_bc_sndlink(net);

        if (!l)
                return -ENOPROTOOPT;

        tipc_bcast_lock(net);
        tipc_link_reset_stats(l);
        tipc_bcast_unlock(net);
        return 0;
}

static int tipc_bc_link_set_queue_limits(struct net *net, u32 limit)
{
        struct tipc_link *l = tipc_bc_sndlink(net);

        if (!l)
                return -ENOPROTOOPT;
        if (limit < BCLINK_WIN_MIN)
                limit = BCLINK_WIN_MIN;
        if (limit > TIPC_MAX_LINK_WIN)
                return -EINVAL;
        tipc_bcast_lock(net);
        tipc_link_set_queue_limits(l, limit);
        tipc_bcast_unlock(net);
        return 0;
}

int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[])
{
        int err;
        u32 win;
        struct nlattr *props[TIPC_NLA_PROP_MAX + 1];

        if (!attrs[TIPC_NLA_LINK_PROP])
                return -EINVAL;

        err = tipc_nl_parse_link_prop(attrs[TIPC_NLA_LINK_PROP], props);
        if (err)
                return err;

        if (!props[TIPC_NLA_PROP_WIN])
                return -EOPNOTSUPP;

        win = nla_get_u32(props[TIPC_NLA_PROP_WIN]);

        return tipc_bc_link_set_queue_limits(net, win);
}

int tipc_bcast_init(struct net *net)
{
        struct tipc_net *tn = tipc_net(net);
        struct tipc_bc_base *bb = NULL;
        struct tipc_link *l = NULL;

        bb = kzalloc(sizeof(*bb), GFP_ATOMIC);
        if (!bb)
                goto enomem;
        tn->bcbase = bb;
        spin_lock_init(&tipc_net(net)->bclock);

        if (!tipc_link_bc_create(net, 0, 0,
                                 U16_MAX,
                                 BCLINK_WIN_DEFAULT,
                                 0,
                                 &bb->inputq,
                                 NULL,
                                 NULL,
                                 &l))
                goto enomem;
        bb->link = l;
        tn->bcl = l;
        return 0;
enomem:
        kfree(bb);
        kfree(l);
        return -ENOMEM;
}

void tipc_bcast_stop(struct net *net)
{
        struct tipc_net *tn = net_generic(net, tipc_net_id);

        synchronize_net();
        kfree(tn->bcbase);
        kfree(tn->bcl);
}