net/ax25/ax25_std_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 028a      Jonathan(G4KLX) New state machine based on SDL diagrams.
  14  *      AX.25 028b      Jonathan(G4KLX) Extracted AX25 control block from the
  15  *                                      sock structure.
  16  *      AX.25 029       Alan(GW4PTS)    Switched to KA9Q constant names.
  17  *      AX.25 031       Joerg(DL1BKE)   Added DAMA support
  18  *      AX.25 032       Joerg(DL1BKE)   Fixed DAMA timeout bug
  19  *      AX.25 033       Jonathan(G4KLX) Modularisation functions.
  20  *      AX.25 035       Frederic(F1OAT) Support for pseudo-digipeating.
  21  *      AX.25 036       Jonathan(G4KLX) Split from ax25_timer.c.
  22  *      AX.25 037       Jonathan(G4KLX) New timer architecture.
  23  */
  24
  25 #include <linux/errno.h>
  26 #include <linux/types.h>
  27 #include <linux/socket.h>
  28 #include <linux/in.h>
  29 #include <linux/kernel.h>
  30 #include <linux/sched.h>
  31 #include <linux/timer.h>
  32 #include <linux/string.h>
  33 #include <linux/sockios.h>
  34 #include <linux/net.h>
  35 #include <net/ax25.h>
  36 #include <linux/inet.h>
  37 #include <linux/netdevice.h>
  38 #include <linux/skbuff.h>
  39 #include <net/sock.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/system.h>
  42 #include <linux/fcntl.h>
  43 #include <linux/mm.h>
  44 #include <linux/interrupt.h>
  45
  46 void ax25_std_heartbeat_expiry(ax25_cb *ax25)
  47 {
  48         switch (ax25->state) {
  49
  50                 case AX25_STATE_0:
  51                         /* Magic here: If we listen() and a new link dies before it
  52                            is accepted() it isn't 'dead' so doesn't get removed. */
  53                         if (ax25->sk == NULL || ax25->sk->destroy || (ax25->sk->state == TCP_LISTEN && ax25->sk->dead)) {
  54                                 ax25_destroy_socket(ax25);
  55                                 return;
  56                         }
  57                         break;
  58
  59                 case AX25_STATE_3:
  60                 case AX25_STATE_4:
  61                         /*
  62                          * Check the state of the receive buffer.
  63                          */
  64                         if (ax25->sk != NULL) {
  65                                 if (atomic_read(&ax25->sk->rmem_alloc) < (ax25->sk->rcvbuf / 2) &&
  66                                     (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
  67                                         ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
  68                                         ax25->condition &= ~AX25_COND_ACK_PENDING;
  69                                         ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
  70                                         break;
  71                                 }
  72                         }
  73         }
  74
  75         ax25_start_heartbeat(ax25);
  76 }
  77
  78 void ax25_std_t2timer_expiry(ax25_cb *ax25)
  79 {
  80         if (ax25->condition & AX25_COND_ACK_PENDING) {
  81                 ax25->condition &= ~AX25_COND_ACK_PENDING;
  82                 ax25_std_timeout_response(ax25);
  83         }
  84 }
  85
  86 void ax25_std_t3timer_expiry(ax25_cb *ax25)
  87 {
  88         ax25->n2count = 0;
  89         ax25_std_transmit_enquiry(ax25);
  90         ax25->state   = AX25_STATE_4;
  91 }
  92
  93 void ax25_std_idletimer_expiry(ax25_cb *ax25)
  94 {
  95         ax25_clear_queues(ax25);
  96
  97         ax25->n2count = 0;
  98         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
  99         ax25->state   = AX25_STATE_2;
 100
 101         ax25_calculate_t1(ax25);
 102         ax25_start_t1timer(ax25);
 103         ax25_stop_t2timer(ax25);
 104         ax25_stop_t3timer(ax25);
 105
 106         if (ax25->sk != NULL) {
 107                 ax25->sk->state     = TCP_CLOSE;
 108                 ax25->sk->err       = 0;
 109                 ax25->sk->shutdown |= SEND_SHUTDOWN;
 110                 if (!ax25->sk->dead)
 111                         ax25->sk->state_change(ax25->sk);
 112                 ax25->sk->dead      = 1;
 113         }
 114 }
 115
 116 void ax25_std_t1timer_expiry(ax25_cb *ax25)
 117 {
 118         switch (ax25->state) {
 119                 case AX25_STATE_1:
 120                         if (ax25->n2count == ax25->n2) {
 121                                 if (ax25->modulus == AX25_MODULUS) {
 122                                         ax25_disconnect(ax25, ETIMEDOUT);
 123                                         return;
 124                                 } else {
 125                                         ax25->modulus = AX25_MODULUS;
 126                                         ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 127                                         ax25->n2count = 0;
 128                                         ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 129                                 }
 130                         } else {
 131                                 ax25->n2count++;
 132                                 if (ax25->modulus == AX25_MODULUS)
 133                                         ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 134                                 else
 135                                         ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
 136                         }
 137                         break;
 138
 139                 case AX25_STATE_2:
 140                         if (ax25->n2count == ax25->n2) {
 141                                 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 142                                 ax25_disconnect(ax25, ETIMEDOUT);
 143                                 return;
 144                         } else {
 145                                 ax25->n2count++;
 146                                 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 147                         }
 148                         break;
 149
 150                 case AX25_STATE_3:
 151                         ax25->n2count = 1;
 152                         ax25_std_transmit_enquiry(ax25);
 153                         ax25->state   = AX25_STATE_4;
 154                         break;
 155
 156                 case AX25_STATE_4:
 157                         if (ax25->n2count == ax25->n2) {
 158                                 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 159                                 ax25_disconnect(ax25, ETIMEDOUT);
 160                                 return;
 161                         } else {
 162                                 ax25->n2count++;
 163                                 ax25_std_transmit_enquiry(ax25);
 164                         }
 165                         break;
 166         }
 167
 168         ax25_calculate_t1(ax25);
 169         ax25_start_t1timer(ax25);
 170 }