linux/net/ax25/ax25_std_timer.c
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   1/*
   2 * This program is free software; you can redistribute it and/or modify
   3 * it under the terms of the GNU General Public License as published by
   4 * the Free Software Foundation; either version 2 of the License, or
   5 * (at your option) any later version.
   6 *
   7 * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
   8 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   9 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
  10 * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
  11 */
  12#include <linux/errno.h>
  13#include <linux/types.h>
  14#include <linux/socket.h>
  15#include <linux/in.h>
  16#include <linux/kernel.h>
  17#include <linux/timer.h>
  18#include <linux/string.h>
  19#include <linux/sockios.h>
  20#include <linux/net.h>
  21#include <net/ax25.h>
  22#include <linux/inet.h>
  23#include <linux/netdevice.h>
  24#include <linux/skbuff.h>
  25#include <net/sock.h>
  26#include <net/tcp_states.h>
  27#include <asm/uaccess.h>
  28#include <linux/fcntl.h>
  29#include <linux/mm.h>
  30#include <linux/interrupt.h>
  31
  32void ax25_std_heartbeat_expiry(ax25_cb *ax25)
  33{
  34        struct sock *sk = ax25->sk;
  35
  36        if (sk)
  37                bh_lock_sock(sk);
  38
  39        switch (ax25->state) {
  40        case AX25_STATE_0:
  41                /* Magic here: If we listen() and a new link dies before it
  42                   is accepted() it isn't 'dead' so doesn't get removed. */
  43                if (!sk || sock_flag(sk, SOCK_DESTROY) ||
  44                    (sk->sk_state == TCP_LISTEN &&
  45                     sock_flag(sk, SOCK_DEAD))) {
  46                        if (sk) {
  47                                sock_hold(sk);
  48                                ax25_destroy_socket(ax25);
  49                                bh_unlock_sock(sk);
  50                                sock_put(sk);
  51                        } else
  52                                ax25_destroy_socket(ax25);
  53                        return;
  54                }
  55                break;
  56
  57        case AX25_STATE_3:
  58        case AX25_STATE_4:
  59                /*
  60                 * Check the state of the receive buffer.
  61                 */
  62                if (sk != NULL) {
  63                        if (atomic_read(&sk->sk_rmem_alloc) <
  64                            (sk->sk_rcvbuf >> 1) &&
  65                            (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
  66                                ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
  67                                ax25->condition &= ~AX25_COND_ACK_PENDING;
  68                                ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
  69                                break;
  70                        }
  71                }
  72        }
  73
  74        if (sk)
  75                bh_unlock_sock(sk);
  76
  77        ax25_start_heartbeat(ax25);
  78}
  79
  80void ax25_std_t2timer_expiry(ax25_cb *ax25)
  81{
  82        if (ax25->condition & AX25_COND_ACK_PENDING) {
  83                ax25->condition &= ~AX25_COND_ACK_PENDING;
  84                ax25_std_timeout_response(ax25);
  85        }
  86}
  87
  88void ax25_std_t3timer_expiry(ax25_cb *ax25)
  89{
  90        ax25->n2count = 0;
  91        ax25_std_transmit_enquiry(ax25);
  92        ax25->state   = AX25_STATE_4;
  93}
  94
  95void ax25_std_idletimer_expiry(ax25_cb *ax25)
  96{
  97        ax25_clear_queues(ax25);
  98
  99        ax25->n2count = 0;
 100        ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 101        ax25->state   = AX25_STATE_2;
 102
 103        ax25_calculate_t1(ax25);
 104        ax25_start_t1timer(ax25);
 105        ax25_stop_t2timer(ax25);
 106        ax25_stop_t3timer(ax25);
 107
 108        if (ax25->sk != NULL) {
 109                bh_lock_sock(ax25->sk);
 110                ax25->sk->sk_state     = TCP_CLOSE;
 111                ax25->sk->sk_err       = 0;
 112                ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
 113                if (!sock_flag(ax25->sk, SOCK_DEAD)) {
 114                        ax25->sk->sk_state_change(ax25->sk);
 115                        sock_set_flag(ax25->sk, SOCK_DEAD);
 116                }
 117                bh_unlock_sock(ax25->sk);
 118        }
 119}
 120
 121void ax25_std_t1timer_expiry(ax25_cb *ax25)
 122{
 123        switch (ax25->state) {
 124        case AX25_STATE_1:
 125                if (ax25->n2count == ax25->n2) {
 126                        if (ax25->modulus == AX25_MODULUS) {
 127                                ax25_disconnect(ax25, ETIMEDOUT);
 128                                return;
 129                        } else {
 130                                ax25->modulus = AX25_MODULUS;
 131                                ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 132                                ax25->n2count = 0;
 133                                ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 134                        }
 135                } else {
 136                        ax25->n2count++;
 137                        if (ax25->modulus == AX25_MODULUS)
 138                                ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 139                        else
 140                                ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
 141                }
 142                break;
 143
 144        case AX25_STATE_2:
 145                if (ax25->n2count == ax25->n2) {
 146                        ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 147                        ax25_disconnect(ax25, ETIMEDOUT);
 148                        return;
 149                } else {
 150                        ax25->n2count++;
 151                        ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 152                }
 153                break;
 154
 155        case AX25_STATE_3:
 156                ax25->n2count = 1;
 157                ax25_std_transmit_enquiry(ax25);
 158                ax25->state   = AX25_STATE_4;
 159                break;
 160
 161        case AX25_STATE_4:
 162                if (ax25->n2count == ax25->n2) {
 163                        ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 164                        ax25_disconnect(ax25, ETIMEDOUT);
 165                        return;
 166                } else {
 167                        ax25->n2count++;
 168                        ax25_std_transmit_enquiry(ax25);
 169                }
 170                break;
 171        }
 172
 173        ax25_calculate_t1(ax25);
 174        ax25_start_t1timer(ax25);
 175}
 176
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