/*
 * net/tipc/node.c: TIPC node management routines
 *
 * Copyright (c) 2000-2006, 2012-2014, Ericsson AB
 * Copyright (c) 2005-2006, 2010-2014, 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 "node.h"
#include "name_distr.h"
#include "socket.h"

#define NODE_HTABLE_SIZE 512

static void node_lost_contact(struct tipc_node *n_ptr);
static void node_established_contact(struct tipc_node *n_ptr);

static struct hlist_head node_htable[NODE_HTABLE_SIZE];
LIST_HEAD(tipc_node_list);
static u32 tipc_num_nodes;
static u32 tipc_num_links;
static DEFINE_SPINLOCK(node_list_lock);

struct tipc_sock_conn {
        u32 port;
        u32 peer_port;
        u32 peer_node;
        struct list_head list;
};

static const struct nla_policy tipc_nl_node_policy[TIPC_NLA_NODE_MAX + 1] = {
        [TIPC_NLA_NODE_UNSPEC]          = { .type = NLA_UNSPEC },
        [TIPC_NLA_NODE_ADDR]            = { .type = NLA_U32 },
        [TIPC_NLA_NODE_UP]              = { .type = NLA_FLAG }
};

/*
 * A trivial power-of-two bitmask technique is used for speed, since this
 * operation is done for every incoming TIPC packet. The number of hash table
 * entries has been chosen so that no hash chain exceeds 8 nodes and will
 * usually be much smaller (typically only a single node).
 */
static unsigned int tipc_hashfn(u32 addr)
{
        return addr & (NODE_HTABLE_SIZE - 1);
}

/*
 * tipc_node_find - locate specified node object, if it exists
 */
struct tipc_node *tipc_node_find(u32 addr)
{
        struct tipc_node *node;

        if (unlikely(!in_own_cluster_exact(addr)))
                return NULL;

        rcu_read_lock();
        hlist_for_each_entry_rcu(node, &node_htable[tipc_hashfn(addr)], hash) {
                if (node->addr == addr) {
                        rcu_read_unlock();
                        return node;
                }
        }
        rcu_read_unlock();
        return NULL;
}

struct tipc_node *tipc_node_create(u32 addr)
{
        struct tipc_node *n_ptr, *temp_node;

        spin_lock_bh(&node_list_lock);

        n_ptr = kzalloc(sizeof(*n_ptr), GFP_ATOMIC);
        if (!n_ptr) {
                spin_unlock_bh(&node_list_lock);
                pr_warn("Node creation failed, no memory\n");
                return NULL;
        }

        n_ptr->addr = addr;
        spin_lock_init(&n_ptr->lock);
        INIT_HLIST_NODE(&n_ptr->hash);
        INIT_LIST_HEAD(&n_ptr->list);
        INIT_LIST_HEAD(&n_ptr->publ_list);
        INIT_LIST_HEAD(&n_ptr->conn_sks);
        skb_queue_head_init(&n_ptr->waiting_sks);
        __skb_queue_head_init(&n_ptr->bclink.deferred_queue);

        hlist_add_head_rcu(&n_ptr->hash, &node_htable[tipc_hashfn(addr)]);

        list_for_each_entry_rcu(temp_node, &tipc_node_list, list) {
                if (n_ptr->addr < temp_node->addr)
                        break;
        }
        list_add_tail_rcu(&n_ptr->list, &temp_node->list);
        n_ptr->action_flags = TIPC_WAIT_PEER_LINKS_DOWN;
        n_ptr->signature = INVALID_NODE_SIG;

        tipc_num_nodes++;

        spin_unlock_bh(&node_list_lock);
        return n_ptr;
}

static void tipc_node_delete(struct tipc_node *n_ptr)
{
        list_del_rcu(&n_ptr->list);
        hlist_del_rcu(&n_ptr->hash);
        kfree_rcu(n_ptr, rcu);

        tipc_num_nodes--;
}

void tipc_node_stop(void)
{
        struct tipc_node *node, *t_node;

        spin_lock_bh(&node_list_lock);
        list_for_each_entry_safe(node, t_node, &tipc_node_list, list)
                tipc_node_delete(node);
        spin_unlock_bh(&node_list_lock);
}

int tipc_node_add_conn(u32 dnode, u32 port, u32 peer_port)
{
        struct tipc_node *node;
        struct tipc_sock_conn *conn;

        if (in_own_node(dnode))
                return 0;

        node = tipc_node_find(dnode);
        if (!node) {
                pr_warn("Connecting sock to node 0x%x failed\n", dnode);
                return -EHOSTUNREACH;
        }
        conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
        if (!conn)
                return -EHOSTUNREACH;
        conn->peer_node = dnode;
        conn->port = port;
        conn->peer_port = peer_port;

        tipc_node_lock(node);
        list_add_tail(&conn->list, &node->conn_sks);
        tipc_node_unlock(node);
        return 0;
}

void tipc_node_remove_conn(u32 dnode, u32 port)
{
        struct tipc_node *node;
        struct tipc_sock_conn *conn, *safe;

        if (in_own_node(dnode))
                return;

        node = tipc_node_find(dnode);
        if (!node)
                return;

        tipc_node_lock(node);
        list_for_each_entry_safe(conn, safe, &node->conn_sks, list) {
                if (port != conn->port)
                        continue;
                list_del(&conn->list);
                kfree(conn);
        }
        tipc_node_unlock(node);
}

void tipc_node_abort_sock_conns(struct list_head *conns)
{
        struct tipc_sock_conn *conn, *safe;
        struct sk_buff *buf;

        list_for_each_entry_safe(conn, safe, conns, list) {
                buf = tipc_msg_create(TIPC_CRITICAL_IMPORTANCE, TIPC_CONN_MSG,
                                      SHORT_H_SIZE, 0, tipc_own_addr,
                                      conn->peer_node, conn->port,
                                      conn->peer_port, TIPC_ERR_NO_NODE);
                if (likely(buf))
                        tipc_sk_rcv(buf);
                list_del(&conn->list);
                kfree(conn);
        }
}

/**
 * tipc_node_link_up - handle addition of link
 *
 * Link becomes active (alone or shared) or standby, depending on its priority.
 */
void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
        struct tipc_link **active = &n_ptr->active_links[0];

        n_ptr->working_links++;
        n_ptr->action_flags |= TIPC_NOTIFY_LINK_UP;
        n_ptr->link_id = l_ptr->peer_bearer_id << 16 | l_ptr->bearer_id;

        pr_info("Established link <%s> on network plane %c\n",
                l_ptr->name, l_ptr->net_plane);

        if (!active[0]) {
                active[0] = active[1] = l_ptr;
                node_established_contact(n_ptr);
                goto exit;
        }
        if (l_ptr->priority < active[0]->priority) {
                pr_info("New link <%s> becomes standby\n", l_ptr->name);
                goto exit;
        }
        tipc_link_dup_queue_xmit(active[0], l_ptr);
        if (l_ptr->priority == active[0]->priority) {
                active[0] = l_ptr;
                goto exit;
        }
        pr_info("Old link <%s> becomes standby\n", active[0]->name);
        if (active[1] != active[0])
                pr_info("Old link <%s> becomes standby\n", active[1]->name);
        active[0] = active[1] = l_ptr;
exit:
        /* Leave room for changeover header when returning 'mtu' to users: */
        n_ptr->act_mtus[0] = active[0]->max_pkt - INT_H_SIZE;
        n_ptr->act_mtus[1] = active[1]->max_pkt - INT_H_SIZE;
}

/**
 * node_select_active_links - select active link
 */
static void node_select_active_links(struct tipc_node *n_ptr)
{
        struct tipc_link **active = &n_ptr->active_links[0];
        u32 i;
        u32 highest_prio = 0;

        active[0] = active[1] = NULL;

        for (i = 0; i < MAX_BEARERS; i++) {
                struct tipc_link *l_ptr = n_ptr->links[i];

                if (!l_ptr || !tipc_link_is_up(l_ptr) ||
                    (l_ptr->priority < highest_prio))
                        continue;

                if (l_ptr->priority > highest_prio) {
                        highest_prio = l_ptr->priority;
                        active[0] = active[1] = l_ptr;
                } else {
                        active[1] = l_ptr;
                }
        }
}

/**
 * tipc_node_link_down - handle loss of link
 */
void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
        struct tipc_link **active;

        n_ptr->working_links--;
        n_ptr->action_flags |= TIPC_NOTIFY_LINK_DOWN;
        n_ptr->link_id = l_ptr->peer_bearer_id << 16 | l_ptr->bearer_id;

        if (!tipc_link_is_active(l_ptr)) {
                pr_info("Lost standby link <%s> on network plane %c\n",
                        l_ptr->name, l_ptr->net_plane);
                return;
        }
        pr_info("Lost link <%s> on network plane %c\n",
                l_ptr->name, l_ptr->net_plane);

        active = &n_ptr->active_links[0];
        if (active[0] == l_ptr)
                active[0] = active[1];
        if (active[1] == l_ptr)
                active[1] = active[0];
        if (active[0] == l_ptr)
                node_select_active_links(n_ptr);
        if (tipc_node_is_up(n_ptr))
                tipc_link_failover_send_queue(l_ptr);
        else
                node_lost_contact(n_ptr);

        /* Leave room for changeover header when returning 'mtu' to users: */
        if (active[0]) {
                n_ptr->act_mtus[0] = active[0]->max_pkt - INT_H_SIZE;
                n_ptr->act_mtus[1] = active[1]->max_pkt - INT_H_SIZE;
                return;
        }

        /* Loopback link went down? No fragmentation needed from now on. */
        if (n_ptr->addr == tipc_own_addr) {
                n_ptr->act_mtus[0] = MAX_MSG_SIZE;
                n_ptr->act_mtus[1] = MAX_MSG_SIZE;
        }
}

int tipc_node_active_links(struct tipc_node *n_ptr)
{
        return n_ptr->active_links[0] != NULL;
}

int tipc_node_is_up(struct tipc_node *n_ptr)
{
        return tipc_node_active_links(n_ptr);
}

void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
        n_ptr->links[l_ptr->bearer_id] = l_ptr;
        spin_lock_bh(&node_list_lock);
        tipc_num_links++;
        spin_unlock_bh(&node_list_lock);
        n_ptr->link_cnt++;
}

void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr)
{
        int i;

        for (i = 0; i < MAX_BEARERS; i++) {
                if (l_ptr != n_ptr->links[i])
                        continue;
                n_ptr->links[i] = NULL;
                spin_lock_bh(&node_list_lock);
                tipc_num_links--;
                spin_unlock_bh(&node_list_lock);
                n_ptr->link_cnt--;
        }
}

static void node_established_contact(struct tipc_node *n_ptr)
{
        n_ptr->action_flags |= TIPC_NOTIFY_NODE_UP;
        n_ptr->bclink.oos_state = 0;
        n_ptr->bclink.acked = tipc_bclink_get_last_sent();
        tipc_bclink_add_node(n_ptr->addr);
}

static void node_lost_contact(struct tipc_node *n_ptr)
{
        char addr_string[16];
        u32 i;

        pr_info("Lost contact with %s\n",
                tipc_addr_string_fill(addr_string, n_ptr->addr));

        /* Flush broadcast link info associated with lost node */
        if (n_ptr->bclink.recv_permitted) {
                __skb_queue_purge(&n_ptr->bclink.deferred_queue);

                if (n_ptr->bclink.reasm_buf) {
                        kfree_skb(n_ptr->bclink.reasm_buf);
                        n_ptr->bclink.reasm_buf = NULL;
                }

                tipc_bclink_remove_node(n_ptr->addr);
                tipc_bclink_acknowledge(n_ptr, INVALID_LINK_SEQ);

                n_ptr->bclink.recv_permitted = false;
        }

        /* Abort link changeover */
        for (i = 0; i < MAX_BEARERS; i++) {
                struct tipc_link *l_ptr = n_ptr->links[i];
                if (!l_ptr)
                        continue;
                l_ptr->reset_checkpoint = l_ptr->next_in_no;
                l_ptr->exp_msg_count = 0;
                tipc_link_reset_fragments(l_ptr);
        }

        n_ptr->action_flags &= ~TIPC_WAIT_OWN_LINKS_DOWN;

        /* Notify subscribers and prevent re-contact with node until
         * cleanup is done.
         */
        n_ptr->action_flags |= TIPC_WAIT_PEER_LINKS_DOWN |
                               TIPC_NOTIFY_NODE_DOWN;
}

struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
{
        u32 domain;
        struct sk_buff *buf;
        struct tipc_node *n_ptr;
        struct tipc_node_info node_info;
        u32 payload_size;

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

        domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (!tipc_addr_domain_valid(domain))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (network address)");

        spin_lock_bh(&node_list_lock);
        if (!tipc_num_nodes) {
                spin_unlock_bh(&node_list_lock);
                return tipc_cfg_reply_none();
        }

        /* For now, get space for all other nodes */
        payload_size = TLV_SPACE(sizeof(node_info)) * tipc_num_nodes;
        if (payload_size > 32768u) {
                spin_unlock_bh(&node_list_lock);
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                                                   " (too many nodes)");
        }
        spin_unlock_bh(&node_list_lock);

        buf = tipc_cfg_reply_alloc(payload_size);
        if (!buf)
                return NULL;

        /* Add TLVs for all nodes in scope */
        rcu_read_lock();
        list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
                if (!tipc_in_scope(domain, n_ptr->addr))
                        continue;
                node_info.addr = htonl(n_ptr->addr);
                node_info.up = htonl(tipc_node_is_up(n_ptr));
                tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
                                    &node_info, sizeof(node_info));
        }
        rcu_read_unlock();
        return buf;
}

struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
{
        u32 domain;
        struct sk_buff *buf;
        struct tipc_node *n_ptr;
        struct tipc_link_info link_info;
        u32 payload_size;

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

        domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
        if (!tipc_addr_domain_valid(domain))
                return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
                                                   " (network address)");

        if (!tipc_own_addr)
                return tipc_cfg_reply_none();

        spin_lock_bh(&node_list_lock);
        /* Get space for all unicast links + broadcast link */
        payload_size = TLV_SPACE((sizeof(link_info)) * (tipc_num_links + 1));
        if (payload_size > 32768u) {
                spin_unlock_bh(&node_list_lock);
                return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
                                                   " (too many links)");
        }
        spin_unlock_bh(&node_list_lock);

        buf = tipc_cfg_reply_alloc(payload_size);
        if (!buf)
                return NULL;

        /* Add TLV for broadcast link */
        link_info.dest = htonl(tipc_cluster_mask(tipc_own_addr));
        link_info.up = htonl(1);
        strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_NAME);
        tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));

        /* Add TLVs for any other links in scope */
        rcu_read_lock();
        list_for_each_entry_rcu(n_ptr, &tipc_node_list, list) {
                u32 i;

                if (!tipc_in_scope(domain, n_ptr->addr))
                        continue;
                tipc_node_lock(n_ptr);
                for (i = 0; i < MAX_BEARERS; i++) {
                        if (!n_ptr->links[i])
                                continue;
                        link_info.dest = htonl(n_ptr->addr);
                        link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
                        strcpy(link_info.str, n_ptr->links[i]->name);
                        tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
                                            &link_info, sizeof(link_info));
                }
                tipc_node_unlock(n_ptr);
        }
        rcu_read_unlock();
        return buf;
}

/**
 * tipc_node_get_linkname - get the name of a link
 *
 * @bearer_id: id of the bearer
 * @node: peer node address
 * @linkname: link name output buffer
 *
 * Returns 0 on success
 */
int tipc_node_get_linkname(u32 bearer_id, u32 addr, char *linkname, size_t len)
{
        struct tipc_link *link;
        struct tipc_node *node = tipc_node_find(addr);

        if ((bearer_id >= MAX_BEARERS) || !node)
                return -EINVAL;
        tipc_node_lock(node);
        link = node->links[bearer_id];
        if (link) {
                strncpy(linkname, link->name, len);
                tipc_node_unlock(node);
                return 0;
        }
        tipc_node_unlock(node);
        return -EINVAL;
}

void tipc_node_unlock(struct tipc_node *node)
{
        LIST_HEAD(nsub_list);
        LIST_HEAD(conn_sks);
        struct sk_buff_head waiting_sks;
        u32 addr = 0;
        int flags = node->action_flags;
        u32 link_id = 0;

        if (likely(!flags)) {
                spin_unlock_bh(&node->lock);
                return;
        }

        addr = node->addr;
        link_id = node->link_id;
        __skb_queue_head_init(&waiting_sks);

        if (flags & TIPC_WAKEUP_USERS)
                skb_queue_splice_init(&node->waiting_sks, &waiting_sks);

        if (flags & TIPC_NOTIFY_NODE_DOWN) {
                list_replace_init(&node->publ_list, &nsub_list);
                list_replace_init(&node->conn_sks, &conn_sks);
        }
        node->action_flags &= ~(TIPC_WAKEUP_USERS | TIPC_NOTIFY_NODE_DOWN |
                                TIPC_NOTIFY_NODE_UP | TIPC_NOTIFY_LINK_UP |
                                TIPC_NOTIFY_LINK_DOWN |
                                TIPC_WAKEUP_BCAST_USERS);

        spin_unlock_bh(&node->lock);

        while (!skb_queue_empty(&waiting_sks))
                tipc_sk_rcv(__skb_dequeue(&waiting_sks));

        if (!list_empty(&conn_sks))
                tipc_node_abort_sock_conns(&conn_sks);

        if (!list_empty(&nsub_list))
                tipc_publ_notify(&nsub_list, addr);

        if (flags & TIPC_WAKEUP_BCAST_USERS)
                tipc_bclink_wakeup_users();

        if (flags & TIPC_NOTIFY_NODE_UP)
                tipc_named_node_up(addr);

        if (flags & TIPC_NOTIFY_LINK_UP)
                tipc_nametbl_publish(TIPC_LINK_STATE, addr, addr,
                                     TIPC_NODE_SCOPE, link_id, addr);

        if (flags & TIPC_NOTIFY_LINK_DOWN)
                tipc_nametbl_withdraw(TIPC_LINK_STATE, addr,
                                      link_id, addr);
}

/* Caller should hold node lock for the passed node */
static int __tipc_nl_add_node(struct tipc_nl_msg *msg, struct tipc_node *node)
{
        void *hdr;
        struct nlattr *attrs;

        hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_v2_family,
                          NLM_F_MULTI, TIPC_NL_NODE_GET);
        if (!hdr)
                return -EMSGSIZE;

        attrs = nla_nest_start(msg->skb, TIPC_NLA_NODE);
        if (!attrs)
                goto msg_full;

        if (nla_put_u32(msg->skb, TIPC_NLA_NODE_ADDR, node->addr))
                goto attr_msg_full;
        if (tipc_node_is_up(node))
                if (nla_put_flag(msg->skb, TIPC_NLA_NODE_UP))
                        goto attr_msg_full;

        nla_nest_end(msg->skb, attrs);
        genlmsg_end(msg->skb, hdr);

        return 0;

attr_msg_full:
        nla_nest_cancel(msg->skb, attrs);
msg_full:
        genlmsg_cancel(msg->skb, hdr);

        return -EMSGSIZE;
}

int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        int err;
        int done = cb->args[0];
        int last_addr = cb->args[1];
        struct tipc_node *node;
        struct tipc_nl_msg msg;

        if (done)
                return 0;

        msg.skb = skb;
        msg.portid = NETLINK_CB(cb->skb).portid;
        msg.seq = cb->nlh->nlmsg_seq;

        rcu_read_lock();

        if (last_addr && !tipc_node_find(last_addr)) {
                rcu_read_unlock();
                /* We never set seq or call nl_dump_check_consistent() this
                 * means that setting prev_seq here will cause the consistence
                 * check to fail in the netlink callback handler. Resulting in
                 * the NLMSG_DONE message having the NLM_F_DUMP_INTR flag set if
                 * the node state changed while we released the lock.
                 */
                cb->prev_seq = 1;
                return -EPIPE;
        }

        list_for_each_entry_rcu(node, &tipc_node_list, list) {
                if (last_addr) {
                        if (node->addr == last_addr)
                                last_addr = 0;
                        else
                                continue;
                }

                tipc_node_lock(node);
                err = __tipc_nl_add_node(&msg, node);
                if (err) {
                        last_addr = node->addr;
                        tipc_node_unlock(node);
                        goto out;
                }

                tipc_node_unlock(node);
        }
        done = 1;
out:
        cb->args[0] = done;
        cb->args[1] = last_addr;
        rcu_read_unlock();

        return skb->len;
}