net/ax25/ax25_ds_timer.c

   1 /*
   2  *      AX.25 release 037
   3  *
   4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   5  *
   6  *      This module:
   7  *              This module is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  *      History
  13  *      AX.25 036       Jonathan(G4KLX) Cloned from ax25_timer.c.
  14  *                      Joerg(DL1BKE)   Added DAMA Slave Timeout timer
  15  *      AX.25 037       Jonathan(G4KLX) New timer architecture.
  16  */
  17
  18 #include <linux/errno.h>
  19 #include <linux/types.h>
  20 #include <linux/socket.h>
  21 #include <linux/in.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/timer.h>
  25 #include <linux/string.h>
  26 #include <linux/sockios.h>
  27 #include <linux/net.h>
  28 #include <net/ax25.h>
  29 #include <linux/inet.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/skbuff.h>
  32 #include <net/sock.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/system.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/mm.h>
  37 #include <linux/interrupt.h>
  38
  39 static void ax25_ds_timeout(unsigned long);
  40
  41 /*
  42  *      Add DAMA slave timeout timer to timer list.
  43  *      Unlike the connection based timers the timeout function gets
  44  *      triggered every second. Please note that NET_AX25_DAMA_SLAVE_TIMEOUT
  45  *      (aka /proc/sys/net/ax25/{dev}/dama_slave_timeout) is still in
  46  *      1/10th of a second.
  47  */
  48
  49 static void ax25_ds_add_timer(ax25_dev *ax25_dev)
  50 {
  51         struct timer_list *t = &ax25_dev->dama.slave_timer;
  52         t->data         = (unsigned long) ax25_dev;
  53         t->function     = &ax25_ds_timeout;
  54         t->expires      = jiffies + HZ;
  55         add_timer(t);
  56 }
  57
  58 void ax25_ds_del_timer(ax25_dev *ax25_dev)
  59 {
  60         if (ax25_dev) del_timer(&ax25_dev->dama.slave_timer);
  61 }
  62
  63 void ax25_ds_set_timer(ax25_dev *ax25_dev)
  64 {
  65         if (ax25_dev == NULL)           /* paranoia */
  66                 return;
  67
  68         del_timer(&ax25_dev->dama.slave_timer);
  69         ax25_dev->dama.slave_timeout = ax25_dev->values[AX25_VALUES_DS_TIMEOUT] / 10;
  70         ax25_ds_add_timer(ax25_dev);
  71 }
  72
  73 /*
  74  *      DAMA Slave Timeout
  75  *      Silently discard all (slave) connections in case our master forgot us...
  76  */
  77
  78 static void ax25_ds_timeout(unsigned long arg)
  79 {
  80         ax25_dev *ax25_dev = (struct ax25_dev *) arg;
  81         ax25_cb *ax25;
  82
  83         if (ax25_dev == NULL || !ax25_dev->dama.slave)
  84                 return;                 /* Yikes! */
  85
  86         if (!ax25_dev->dama.slave_timeout || --ax25_dev->dama.slave_timeout) {
  87                 ax25_ds_set_timer(ax25_dev);
  88                 return;
  89         }
  90
  91         for (ax25=ax25_list; ax25 != NULL; ax25 = ax25->next) {
  92                 if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
  93                         continue;
  94
  95                 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
  96                 ax25_disconnect(ax25, ETIMEDOUT);
  97         }
  98
  99         ax25_dev_dama_off(ax25_dev);
 100 }
 101
 102 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
 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 (ax25->sk == NULL || ax25->sk->destroy || (ax25->sk->state == TCP_LISTEN && ax25->sk->dead)) {
 110                                 ax25_destroy_socket(ax25);
 111                                 return;
 112                         }
 113                         break;
 114
 115                 case AX25_STATE_3:
 116                         /*
 117                          * Check the state of the receive buffer.
 118                          */
 119                         if (ax25->sk != NULL) {
 120                                 if (atomic_read(&ax25->sk->rmem_alloc) < (ax25->sk->rcvbuf / 2) &&
 121                                     (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
 122                                         ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
 123                                         ax25->condition &= ~AX25_COND_ACK_PENDING;
 124                                         break;
 125                                 }
 126                         }
 127                         break;
 128         }
 129
 130         ax25_start_heartbeat(ax25);
 131 }
 132
 133 /* dl1bke 960114: T3 works much like the IDLE timeout, but
 134  *                gets reloaded with every frame for this
 135  *                connection.
 136  */
 137 void ax25_ds_t3timer_expiry(ax25_cb *ax25)
 138 {
 139         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 140         ax25_dama_off(ax25);
 141         ax25_disconnect(ax25, ETIMEDOUT);
 142 }
 143
 144 /* dl1bke 960228: close the connection when IDLE expires.
 145  *                unlike T3 this timer gets reloaded only on
 146  *                I frames.
 147  */
 148 void ax25_ds_idletimer_expiry(ax25_cb *ax25)
 149 {
 150         ax25_clear_queues(ax25);
 151
 152         ax25->n2count = 0;
 153         ax25->state = AX25_STATE_2;
 154
 155         ax25_calculate_t1(ax25);
 156         ax25_start_t1timer(ax25);
 157         ax25_stop_t3timer(ax25);
 158
 159         if (ax25->sk != NULL) {
 160                 ax25->sk->state     = TCP_CLOSE;
 161                 ax25->sk->err       = 0;
 162                 ax25->sk->shutdown |= SEND_SHUTDOWN;
 163                 if (!ax25->sk->dead)
 164                         ax25->sk->state_change(ax25->sk);
 165                 ax25->sk->dead      = 1;
 166         }
 167 }
 168
 169 /* dl1bke 960114: The DAMA protocol requires to send data and SABM/DISC
 170  *                within the poll of any connected channel. Remember
 171  *                that we are not allowed to send anything unless we
 172  *                get polled by the Master.
 173  *
 174  *                Thus we'll have to do parts of our T1 handling in
 175  *                ax25_enquiry_response().
 176  */
 177 void ax25_ds_t1_timeout(ax25_cb *ax25)
 178 {
 179         switch (ax25->state) {
 180
 181                 case AX25_STATE_1:
 182                         if (ax25->n2count == ax25->n2) {
 183                                 if (ax25->modulus == AX25_MODULUS) {
 184                                         ax25_disconnect(ax25, ETIMEDOUT);
 185                                         return;
 186                                 } else {
 187                                         ax25->modulus = AX25_MODULUS;
 188                                         ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 189                                         ax25->n2count = 0;
 190                                         ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 191                                 }
 192                         } else {
 193                                 ax25->n2count++;
 194                                 if (ax25->modulus == AX25_MODULUS)
 195                                         ax25_send_control(ax25, AX25_SABM, AX25_POLLOFF, AX25_COMMAND);
 196                                 else
 197                                         ax25_send_control(ax25, AX25_SABME, AX25_POLLOFF, AX25_COMMAND);
 198                         }
 199                         break;
 200
 201                 case AX25_STATE_2:
 202                         if (ax25->n2count == ax25->n2) {
 203                                 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 204                                 ax25_disconnect(ax25, ETIMEDOUT);
 205                                 return;
 206                         } else {
 207                                 ax25->n2count++;
 208                         }
 209                         break;
 210
 211                 case AX25_STATE_3:
 212                         if (ax25->n2count == ax25->n2) {
 213                                 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 214                                 ax25_disconnect(ax25, ETIMEDOUT);
 215                                 return;
 216                         } else {
 217                                 ax25->n2count++;
 218                         }
 219                         break;
 220         }
 221
 222         ax25_calculate_t1(ax25);
 223         ax25_start_t1timer(ax25);
 224 }