/*
 * proc_llc.c - proc interface for LLC
 *
 * Copyright (c) 2001 by Jay Schulist <jschlst@samba.org>
 *               2002-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 * This program can be redistributed or modified under the terms of the
 * GNU General Public License as published by the Free Software Foundation.
 * This program is distributed without any warranty or implied warranty
 * of merchantability or fitness for a particular purpose.
 *
 * See the GNU General Public License for more details.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/errno.h>
#include <linux/seq_file.h>
#include <linux/export.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/llc.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_st.h>
#include <net/llc_conn.h>

static void llc_ui_format_mac(struct seq_file *seq, const u8 *addr)
{
        seq_printf(seq, "%pM", addr);
}

static struct sock *llc_get_sk_idx(loff_t pos)
{
        struct llc_sap *sap;
        struct sock *sk = NULL;
        int i;

        list_for_each_entry_rcu(sap, &llc_sap_list, node) {
                spin_lock_bh(&sap->sk_lock);
                for (i = 0; i < LLC_SK_LADDR_HASH_ENTRIES; i++) {
                        struct hlist_nulls_head *head = &sap->sk_laddr_hash[i];
                        struct hlist_nulls_node *node;

                        sk_nulls_for_each(sk, node, head) {
                                if (!pos)
                                        goto found; /* keep the lock */
                                --pos;
                        }
                }
                spin_unlock_bh(&sap->sk_lock);
        }
        sk = NULL;
found:
        return sk;
}

static void *llc_seq_start(struct seq_file *seq, loff_t *pos) __acquires(RCU)
{
        loff_t l = *pos;

        rcu_read_lock_bh();
        return l ? llc_get_sk_idx(--l) : SEQ_START_TOKEN;
}

static struct sock *laddr_hash_next(struct llc_sap *sap, int bucket)
{
        struct hlist_nulls_node *node;
        struct sock *sk = NULL;

        while (++bucket < LLC_SK_LADDR_HASH_ENTRIES)
                sk_nulls_for_each(sk, node, &sap->sk_laddr_hash[bucket])
                        goto out;

out:
        return sk;
}

static void *llc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
        struct sock* sk, *next;
        struct llc_sock *llc;
        struct llc_sap *sap;

        ++*pos;
        if (v == SEQ_START_TOKEN) {
                sk = llc_get_sk_idx(0);
                goto out;
        }
        sk = v;
        next = sk_nulls_next(sk);
        if (next) {
                sk = next;
                goto out;
        }
        llc = llc_sk(sk);
        sap = llc->sap;
        sk = laddr_hash_next(sap, llc_sk_laddr_hashfn(sap, &llc->laddr));
        if (sk)
                goto out;
        spin_unlock_bh(&sap->sk_lock);
        list_for_each_entry_continue_rcu(sap, &llc_sap_list, node) {
                spin_lock_bh(&sap->sk_lock);
                sk = laddr_hash_next(sap, -1);
                if (sk)
                        break; /* keep the lock */
                spin_unlock_bh(&sap->sk_lock);
        }
out:
        return sk;
}

static void llc_seq_stop(struct seq_file *seq, void *v)
{
        if (v && v != SEQ_START_TOKEN) {
                struct sock *sk = v;
                struct llc_sock *llc = llc_sk(sk);
                struct llc_sap *sap = llc->sap;

                spin_unlock_bh(&sap->sk_lock);
        }
        rcu_read_unlock_bh();
}

static int llc_seq_socket_show(struct seq_file *seq, void *v)
{
        struct sock* sk;
        struct llc_sock *llc;

        if (v == SEQ_START_TOKEN) {
                seq_puts(seq, "SKt Mc local_mac_sap        remote_mac_sap   "
                              "    tx_queue rx_queue st uid link\n");
                goto out;
        }
        sk = v;
        llc = llc_sk(sk);

        /* FIXME: check if the address is multicast */
        seq_printf(seq, "%2X  %2X ", sk->sk_type, 0);

        if (llc->dev)
                llc_ui_format_mac(seq, llc->dev->dev_addr);
        else {
                u8 addr[6] = {0,0,0,0,0,0};
                llc_ui_format_mac(seq, addr);
        }
        seq_printf(seq, "@%02X ", llc->sap->laddr.lsap);
        llc_ui_format_mac(seq, llc->daddr.mac);
        seq_printf(seq, "@%02X %8d %8d %2d %3u %4d\n", llc->daddr.lsap,
                   sk_wmem_alloc_get(sk),
                   sk_rmem_alloc_get(sk) - llc->copied_seq,
                   sk->sk_state,
                   from_kuid_munged(seq_user_ns(seq), sk_uid(sk)),
                   llc->link);
out:
        return 0;
}

static const char *const llc_conn_state_names[] = {
        [LLC_CONN_STATE_ADM] =        "adm",
        [LLC_CONN_STATE_SETUP] =      "setup",
        [LLC_CONN_STATE_NORMAL] =     "normal",
        [LLC_CONN_STATE_BUSY] =       "busy",
        [LLC_CONN_STATE_REJ] =        "rej",
        [LLC_CONN_STATE_AWAIT] =      "await",
        [LLC_CONN_STATE_AWAIT_BUSY] = "await_busy",
        [LLC_CONN_STATE_AWAIT_REJ] =  "await_rej",
        [LLC_CONN_STATE_D_CONN] =     "d_conn",
        [LLC_CONN_STATE_RESET] =      "reset",
        [LLC_CONN_STATE_ERROR] =      "error",
        [LLC_CONN_STATE_TEMP] =       "temp",
};

static int llc_seq_core_show(struct seq_file *seq, void *v)
{
        struct sock* sk;
        struct llc_sock *llc;

        if (v == SEQ_START_TOKEN) {
                seq_puts(seq, "Connection list:\n"
                              "dsap state      retr txw rxw pf ff sf df rs cs "
                              "tack tpfc trs tbs blog busr\n");
                goto out;
        }
        sk = v;
        llc = llc_sk(sk);

        seq_printf(seq, " %02X  %-10s %3d  %3d %3d %2d %2d %2d %2d %2d %2d "
                        "%4d %4d %3d %3d %4d %4d\n",
                   llc->daddr.lsap, llc_conn_state_names[llc->state],
                   llc->retry_count, llc->k, llc->rw, llc->p_flag, llc->f_flag,
                   llc->s_flag, llc->data_flag, llc->remote_busy_flag,
                   llc->cause_flag, timer_pending(&llc->ack_timer.timer),
                   timer_pending(&llc->pf_cycle_timer.timer),
                   timer_pending(&llc->rej_sent_timer.timer),
                   timer_pending(&llc->busy_state_timer.timer),
                   !!sk->sk_backlog.tail, sock_owned_by_user_nocheck(sk));
out:
        return 0;
}

static const struct seq_operations llc_seq_socket_ops = {
        .start  = llc_seq_start,
        .next   = llc_seq_next,
        .stop   = llc_seq_stop,
        .show   = llc_seq_socket_show,
};

static const struct seq_operations llc_seq_core_ops = {
        .start  = llc_seq_start,
        .next   = llc_seq_next,
        .stop   = llc_seq_stop,
        .show   = llc_seq_core_show,
};

static struct proc_dir_entry *llc_proc_dir;

int __init llc_proc_init(void)
{
        int rc = -ENOMEM;
        struct proc_dir_entry *p;

        llc_proc_dir = proc_mkdir("llc", init_net.proc_net);
        if (!llc_proc_dir)
                goto out;

        p = proc_create_seq("socket", 0444, llc_proc_dir, &llc_seq_socket_ops);
        if (!p)
                goto out_socket;

        p = proc_create_seq("core", 0444, llc_proc_dir, &llc_seq_core_ops);
        if (!p)
                goto out_core;

        rc = 0;
out:
        return rc;
out_core:
        remove_proc_entry("socket", llc_proc_dir);
out_socket:
        remove_proc_entry("llc", init_net.proc_net);
        goto out;
}

void llc_proc_exit(void)
{
        remove_proc_entry("socket", llc_proc_dir);
        remove_proc_entry("core", llc_proc_dir);
        remove_proc_entry("llc", init_net.proc_net);
}