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