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.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 = ax25_dev->values[AX25_VALUES_DS_TIMEOUT] / 10;
  65         ax25_ds_add_timer(ax25_dev);
  66 }
  67
  68 /*
  69  *      DAMA Slave Timeout
  70  *      Silently discard all (slave) connections in case our master forgot us...
  71  */
  72
  73 static void ax25_ds_timeout(unsigned long arg)
  74 {
  75         ax25_dev *ax25_dev = (struct ax25_dev *) arg;
  76         ax25_cb *ax25;
  77         struct hlist_node *node;
  78
  79         if (ax25_dev == NULL || !ax25_dev->dama.slave)
  80                 return;                 /* Yikes! */
  81
  82         if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
  83                 ax25_ds_set_timer(ax25_dev);
  84                 return;
  85         }
  86
  87         spin_lock_bh(&ax25_list_lock);
  88         ax25_for_each(ax25, node, &ax25_list) {
  89                 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
  90                         continue;
  91
  92                 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
  93                 ax25_disconnect(ax25, ETIMEDOUT);
  94         }
  95         spin_unlock_bh(&ax25_list_lock);
  96
  97         ax25_dev_dama_off(ax25_dev);
  98 }
  99
 100 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
 101 {
 102         struct sock *sk=ax25->sk;
 103
 104         if (sk)
 105                 bh_lock_sock(sk);
 106
 107         switch (ax25->state) {
 108
 109         case AX25_STATE_0:
 110                 /* Magic here: If we listen() and a new link dies before it
 111                    is accepted() it isn't 'dead' so doesn't get removed. */
 112                 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
 113                     (sk->sk_state == TCP_LISTEN &&
 114                      sock_flag(sk, SOCK_DEAD))) {
 115                         if (sk) {
 116                                 sock_hold(sk);
 117                                 ax25_destroy_socket(ax25);
 118                                 sock_put(sk);
 119                                 bh_unlock_sock(sk);
 120                         } else
 121                                 ax25_destroy_socket(ax25);
 122                         return;
 123                 }
 124                 break;
 125
 126         case AX25_STATE_3:
 127                 /*
 128                  * Check the state of the receive buffer.
 129                  */
 130                 if (sk != NULL) {
 131                         if (atomic_read(&sk->sk_rmem_alloc) <
 132                             (sk->sk_rcvbuf / 2) &&
 133                             (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
 134                                 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
 135                                 ax25->condition &= ~AX25_COND_ACK_PENDING;
 136                                 break;
 137                         }
 138                 }
 139                 break;
 140         }
 141
 142         if (sk)
 143                 bh_unlock_sock(sk);
 144
 145         ax25_start_heartbeat(ax25);
 146 }
 147
 148 /* dl1bke 960114: T3 works much like the IDLE timeout, but
 149  *                gets reloaded with every frame for this
 150  *                connection.
 151  */
 152 void ax25_ds_t3timer_expiry(ax25_cb *ax25)
 153 {
 154         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 155         ax25_dama_off(ax25);
 156         ax25_disconnect(ax25, ETIMEDOUT);
 157 }
 158
 159 /* dl1bke 960228: close the connection when IDLE expires.
 160  *                unlike T3 this timer gets reloaded only on
 161  *                I frames.
 162  */
 163 void ax25_ds_idletimer_expiry(ax25_cb *ax25)
 164 {
 165         ax25_clear_queues(ax25);
 166
 167         ax25->n2count = 0;
 168         ax25->state = AX25_STATE_2;
 169
 170         ax25_calculate_t1(ax25);
 171         ax25_start_t1timer(ax25);
 172         ax25_stop_t3timer(ax25);
 173
 174         if (ax25->sk != NULL) {
 175                 bh_lock_sock(ax25->sk);
 176                 ax25->sk->sk_state     = TCP_CLOSE;
 177                 ax25->sk->sk_err       = 0;
 178                 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
 179                 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
 180                         ax25->sk->sk_state_change(ax25->sk);
 181                         sock_set_flag(ax25->sk, SOCK_DEAD);
 182                 }
 183                 bh_unlock_sock(ax25->sk);
 184         }
 185 }
 186
 187 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
 188  *                within the poll of any connected channel. Remember
 189  *                that we are not allowed to send anything unless we
 190  *                get polled by the Master.
 191  *
 192  *                Thus we'll have to do parts of our T1 handling in
 193  *                ax25_enquiry_response().
 194  */
 195 void ax25_ds_t1_timeout(ax25_cb *ax25)
 196 {
 197         switch (ax25->state) {
 198         case AX25_STATE_1:
 199                 if (ax25->n2count == ax25->n2) {
 200                         if (ax25->modulus == AX25_MODULUS) {
 201                                 ax25_disconnect(ax25, ETIMEDOUT);
 202                                 return;
 203                         } else {
 204                                 ax25->modulus = AX25_MODULUS;
 205                                 ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 206                                 ax25->n2count = 0;
 207                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 208                         }
 209                 } else {
 210                         ax25->n2count++;
 211                         if (ax25->modulus == AX25_MODULUS)
 212                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 213                         else
 214                                 ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
 215                 }
 216                 break;
 217
 218         case AX25_STATE_2:
 219                 if (ax25->n2count == ax25->n2) {
 220                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 221                         ax25_disconnect(ax25, ETIMEDOUT);
 222                         return;
 223                 } else {
 224                         ax25->n2count++;
 225                 }
 226                 break;
 227
 228         case AX25_STATE_3:
 229                 if (ax25->n2count == ax25->n2) {
 230                         ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 231                         ax25_disconnect(ax25, ETIMEDOUT);
 232                         return;
 233                 } else {
 234                         ax25->n2count++;
 235                 }
 236                 break;
 237         }
 238
 239         ax25_calculate_t1(ax25);
 240         ax25_start_t1timer(ax25);
 241 }