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 static void ax25_ds_add_timer(ax25_dev *ax25_dev)
  44 {
  45         struct timer_list *t = &ax25_dev->dama.slave_timer;
  46         t->data         = (unsigned long) ax25_dev;
  47         t->function     = &ax25_ds_timeout;
  48         t->expires      = jiffies + HZ;
  49         add_timer(t);
  50 }
  51
  52 void ax25_ds_del_timer(ax25_dev *ax25_dev)
  53 {
  54         if (ax25_dev)
  55                 del_timer(&ax25_dev->dama.slave_timer);
  56 }
  57
  58 void ax25_ds_set_timer(ax25_dev *ax25_dev)
  59 {
  60         if (ax25_dev == NULL)           /* paranoia */
  61                 return;
  62
  63         del_timer(&ax25_dev->dama.slave_timer);
  64         ax25_dev->dama.slave_timeout =
  65                 msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
  66         ax25_ds_add_timer(ax25_dev);
  67 }
  68
  69 /*
  70  *      DAMA Slave Timeout
  71  *      Silently discard all (slave) connections in case our master forgot us...
  72  */
  73
  74 static void ax25_ds_timeout(unsigned long arg)
  75 {
  76         ax25_dev *ax25_dev = (struct ax25_dev *) arg;
  77         ax25_cb *ax25;
  78         struct hlist_node *node;
  79
  80         if (ax25_dev == NULL || !ax25_dev->dama.slave)
  81                 return;                 /* Yikes! */
  82
  83         if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
  84                 ax25_ds_set_timer(ax25_dev);
  85                 return;
  86         }
  87
  88         spin_lock(&ax25_list_lock);
  89         ax25_for_each(ax25, node, &ax25_list) {
  90                 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
  91                         continue;
  92
  93                 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
  94                 ax25_disconnect(ax25, ETIMEDOUT);
  95         }
  96         spin_unlock(&ax25_list_lock);
  97
  98         ax25_dev_dama_off(ax25_dev);
  99 }
 100
 101 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
 102 {
 103         struct sock *sk=ax25->sk;
 104
 105         if (sk)
 106                 bh_lock_sock(sk);
 107
 108         switch (ax25->state) {
 109
 110         case AX25_STATE_0:
 111                 /* Magic here: If we listen() and a new link dies before it
 112                    is accepted() it isn't 'dead' so doesn't get removed. */
 113                 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
 114                     (sk->sk_state == TCP_LISTEN &&
 115                      sock_flag(sk, SOCK_DEAD))) {
 116                         if (sk) {
 117                                 sock_hold(sk);
 118                                 ax25_destroy_socket(ax25);
 119                                 sock_put(sk);
 120                                 bh_unlock_sock(sk);
 121                         } else
 122                                 ax25_destroy_socket(ax25);
 123                         return;
 124                 }
 125                 break;
 126
 127         case AX25_STATE_3:
 128                 /*
 129                  * Check the state of the receive buffer.
 130                  */
 131                 if (sk != NULL) {
 132                         if (atomic_read(&sk->sk_rmem_alloc) <
 133                             (sk->sk_rcvbuf >> 1) &&
 134                             (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
 135                                 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
 136                                 ax25->condition &= ~AX25_COND_ACK_PENDING;
 137                                 break;
 138                         }
 139                 }
 140                 break;
 141         }
 142
 143         if (sk)
 144                 bh_unlock_sock(sk);
 145
 146         ax25_start_heartbeat(ax25);
 147 }
 148
 149 /* dl1bke 960114: T3 works much like the IDLE timeout, but
 150  *                gets reloaded with every frame for this
 151  *                connection.
 152  */
 153 void ax25_ds_t3timer_expiry(ax25_cb *ax25)
 154 {
 155         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 156         ax25_dama_off(ax25);
 157         ax25_disconnect(ax25, ETIMEDOUT);
 158 }
 159
 160 /* dl1bke 960228: close the connection when IDLE expires.
 161  *                unlike T3 this timer gets reloaded only on
 162  *                I frames.
 163  */
 164 void ax25_ds_idletimer_expiry(ax25_cb *ax25)
 165 {
 166         ax25_clear_queues(ax25);
 167
 168         ax25->n2count = 0;
 169         ax25->state = AX25_STATE_2;
 170
 171         ax25_calculate_t1(ax25);
 172         ax25_start_t1timer(ax25);
 173         ax25_stop_t3timer(ax25);
 174
 175         if (ax25->sk != NULL) {
 176                 bh_lock_sock(ax25->sk);
 177                 ax25->sk->sk_state     = TCP_CLOSE;
 178                 ax25->sk->sk_err       = 0;
 179                 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
 180                 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
 181                         ax25->sk->sk_state_change(ax25->sk);
 182                         sock_set_flag(ax25->sk, SOCK_DEAD);
 183                 }
 184                 bh_unlock_sock(ax25->sk);
 185         }
 186 }
 187
 188 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
 189  *                within the poll of any connected channel. Remember
 190  *                that we are not allowed to send anything unless we
 191  *                get polled by the Master.
 192  *
 193  *                Thus we'll have to do parts of our T1 handling in
 194  *                ax25_enquiry_response().
 195  */
 196 void ax25_ds_t1_timeout(ax25_cb *ax25)
 197 {
 198         switch (ax25->state) {
 199         case AX25_STATE_1:
 200                 if (ax25->n2count == ax25->n2) {
 201                         if (ax25->modulus == AX25_MODULUS) {
 202                                 ax25_disconnect(ax25, ETIMEDOUT);
 203                                 return;
 204                         } else {
 205                                 ax25->modulus = AX25_MODULUS;
 206                                 ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 207                                 ax25->n2count = 0;
 208                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 209                         }
 210                 } else {
 211                         ax25->n2count++;
 212                         if (ax25->modulus == AX25_MODULUS)
 213                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 214                         else
 215                                 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
 216                 }
 217                 break;
 218
 219         case AX25_STATE_2:
 220                 if (ax25->n2count == ax25->n2) {
 221                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 222                         ax25_disconnect(ax25, ETIMEDOUT);
 223                         return;
 224                 } else {
 225                         ax25->n2count++;
 226                 }
 227                 break;
 228
 229         case AX25_STATE_3:
 230                 if (ax25->n2count == ax25->n2) {
 231                         ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 232                         ax25_disconnect(ax25, ETIMEDOUT);
 233                         return;
 234                 } else {
 235                         ax25->n2count++;
 236                 }
 237                 break;
 238         }
 239
 240         ax25_calculate_t1(ax25);
 241         ax25_start_t1timer(ax25);
 242 }