net/ax25/ax25_ds_timer.c

   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) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   8  * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
   9  */
  10 #include <linux/errno.h>
  11 #include <linux/types.h>
  12 #include <linux/socket.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/in.h>
  15 #include <linux/kernel.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/timer.h>
  18 #include <linux/string.h>
  19 #include <linux/sockios.h>
  20 #include <linux/net.h>
  21 #include <net/tcp_states.h>
  22 #include <net/ax25.h>
  23 #include <linux/inet.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/skbuff.h>
  26 #include <net/sock.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/fcntl.h>
  29 #include <linux/mm.h>
  30 #include <linux/interrupt.h>
  31
  32 static void ax25_ds_timeout(struct timer_list *);
  33
  34 /*
  35  *      Add DAMA slave timeout timer to timer list.
  36  *      Unlike the connection based timers the timeout function gets
  37  *      triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
  38  *      (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
  39  *      1/10th of a second.
  40  */
  41
  42 void ax25_ds_setup_timer(ax25_dev *ax25_dev)
  43 {
  44         timer_setup(&ax25_dev->dama.slave_timer, ax25_ds_timeout, 0);
  45 }
  46
  47 void ax25_ds_del_timer(ax25_dev *ax25_dev)
  48 {
  49         if (ax25_dev)
  50                 del_timer(&ax25_dev->dama.slave_timer);
  51 }
  52
  53 void ax25_ds_set_timer(ax25_dev *ax25_dev)
  54 {
  55         if (ax25_dev == NULL)           /* paranoia */
  56                 return;
  57
  58         ax25_dev->dama.slave_timeout =
  59                 msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
  60         mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
  61 }
  62
  63 /*
  64  *      DAMA Slave Timeout
  65  *      Silently discard all (slave) connections in case our master forgot us...
  66  */
  67
  68 static void ax25_ds_timeout(struct timer_list *t)
  69 {
  70         ax25_dev *ax25_dev = from_timer(ax25_dev, t, dama.slave_timer);
  71         ax25_cb *ax25;
  72
  73         if (ax25_dev == NULL || !ax25_dev->dama.slave)
  74                 return;                 /* Yikes! */
  75
  76         if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
  77                 ax25_ds_set_timer(ax25_dev);
  78                 return;
  79         }
  80
  81         spin_lock(&ax25_list_lock);
  82         ax25_for_each(ax25, &ax25_list) {
  83                 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
  84                         continue;
  85
  86                 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
  87                 ax25_disconnect(ax25, ETIMEDOUT);
  88         }
  89         spin_unlock(&ax25_list_lock);
  90
  91         ax25_dev_dama_off(ax25_dev);
  92 }
  93
  94 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
  95 {
  96         struct sock *sk=ax25->sk;
  97
  98         if (sk)
  99                 bh_lock_sock(sk);
 100
 101         switch (ax25->state) {
 102
 103         case AX25_STATE_0:
 104         case AX25_STATE_2:
 105                 /* Magic here: If we listen() and a new link dies before it
 106                    is accepted() it isn't 'dead' so doesn't get removed. */
 107                 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
 108                     (sk->sk_state == TCP_LISTEN &&
 109                      sock_flag(sk, SOCK_DEAD))) {
 110                         if (sk) {
 111                                 sock_hold(sk);
 112                                 ax25_destroy_socket(ax25);
 113                                 bh_unlock_sock(sk);
 114                                 /* Ungrab socket and destroy it */
 115                                 sock_put(sk);
 116                         } else
 117                                 ax25_destroy_socket(ax25);
 118                         return;
 119                 }
 120                 break;
 121
 122         case AX25_STATE_3:
 123                 /*
 124                  * Check the state of the receive buffer.
 125                  */
 126                 if (sk != NULL) {
 127                         if (atomic_read(&sk->sk_rmem_alloc) <
 128                             (sk->sk_rcvbuf >> 1) &&
 129                             (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
 130                                 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
 131                                 ax25->condition &= ~AX25_COND_ACK_PENDING;
 132                                 break;
 133                         }
 134                 }
 135                 break;
 136         }
 137
 138         if (sk)
 139                 bh_unlock_sock(sk);
 140
 141         ax25_start_heartbeat(ax25);
 142 }
 143
 144 /* dl1bke 960114: T3 works much like the IDLE timeout, but
 145  *                gets reloaded with every frame for this
 146  *                connection.
 147  */
 148 void ax25_ds_t3timer_expiry(ax25_cb *ax25)
 149 {
 150         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 151         ax25_dama_off(ax25);
 152         ax25_disconnect(ax25, ETIMEDOUT);
 153 }
 154
 155 /* dl1bke 960228: close the connection when IDLE expires.
 156  *                unlike T3 this timer gets reloaded only on
 157  *                I frames.
 158  */
 159 void ax25_ds_idletimer_expiry(ax25_cb *ax25)
 160 {
 161         ax25_clear_queues(ax25);
 162
 163         ax25->n2count = 0;
 164         ax25->state = AX25_STATE_2;
 165
 166         ax25_calculate_t1(ax25);
 167         ax25_start_t1timer(ax25);
 168         ax25_stop_t3timer(ax25);
 169
 170         if (ax25->sk != NULL) {
 171                 bh_lock_sock(ax25->sk);
 172                 ax25->sk->sk_state     = TCP_CLOSE;
 173                 ax25->sk->sk_err       = 0;
 174                 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
 175                 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
 176                         ax25->sk->sk_state_change(ax25->sk);
 177                         sock_set_flag(ax25->sk, SOCK_DEAD);
 178                 }
 179                 bh_unlock_sock(ax25->sk);
 180         }
 181 }
 182
 183 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
 184  *                within the poll of any connected channel. Remember
 185  *                that we are not allowed to send anything unless we
 186  *                get polled by the Master.
 187  *
 188  *                Thus we'll have to do parts of our T1 handling in
 189  *                ax25_enquiry_response().
 190  */
 191 void ax25_ds_t1_timeout(ax25_cb *ax25)
 192 {
 193         switch (ax25->state) {
 194         case AX25_STATE_1:
 195                 if (ax25->n2count == ax25->n2) {
 196                         if (ax25->modulus == AX25_MODULUS) {
 197                                 ax25_disconnect(ax25, ETIMEDOUT);
 198                                 return;
 199                         } else {
 200                                 ax25->modulus = AX25_MODULUS;
 201                                 ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 202                                 ax25->n2count = 0;
 203                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 204                         }
 205                 } else {
 206                         ax25->n2count++;
 207                         if (ax25->modulus == AX25_MODULUS)
 208                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 209                         else
 210                                 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
 211                 }
 212                 break;
 213
 214         case AX25_STATE_2:
 215                 if (ax25->n2count == ax25->n2) {
 216                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 217                         if (!sock_flag(ax25->sk, SOCK_DESTROY))
 218                                 ax25_disconnect(ax25, ETIMEDOUT);
 219                         return;
 220                 } else {
 221                         ax25->n2count++;
 222                 }
 223                 break;
 224
 225         case AX25_STATE_3:
 226                 if (ax25->n2count == ax25->n2) {
 227                         ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 228                         ax25_disconnect(ax25, ETIMEDOUT);
 229                         return;
 230                 } else {
 231                         ax25->n2count++;
 232                 }
 233                 break;
 234         }
 235
 236         ax25_calculate_t1(ax25);
 237         ax25_start_t1timer(ax25);
 238 }