net/ax25/ax25_std_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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
   8  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   9  * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
  10  * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
  11  */
  12 #include <linux/errno.h>
  13 #include <linux/types.h>
  14 #include <linux/socket.h>
  15 #include <linux/in.h>
  16 #include <linux/kernel.h>
  17 #include <linux/timer.h>
  18 #include <linux/string.h>
  19 #include <linux/sockios.h>
  20 #include <linux/net.h>
  21 #include <net/ax25.h>
  22 #include <linux/inet.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/skbuff.h>
  25 #include <net/sock.h>
  26 #include <net/tcp_states.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 void ax25_std_heartbeat_expiry(ax25_cb *ax25)
  34 {
  35         struct sock *sk = ax25->sk;
  36
  37         if (sk)
  38                 bh_lock_sock(sk);
  39
  40         switch (ax25->state) {
  41         case AX25_STATE_0:
  42                 /* Magic here: If we listen() and a new link dies before it
  43                    is accepted() it isn't 'dead' so doesn't get removed. */
  44                 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
  45                     (sk->sk_state == TCP_LISTEN &&
  46                      sock_flag(sk, SOCK_DEAD))) {
  47                         if (sk) {
  48                                 sock_hold(sk);
  49                                 ax25_destroy_socket(ax25);
  50                                 bh_unlock_sock(sk);
  51                                 sock_put(sk);
  52                         } else
  53                                 ax25_destroy_socket(ax25);
  54                         return;
  55                 }
  56                 break;
  57
  58         case AX25_STATE_3:
  59         case AX25_STATE_4:
  60                 /*
  61                  * Check the state of the receive buffer.
  62                  */
  63                 if (sk != NULL) {
  64                         if (atomic_read(&sk->sk_rmem_alloc) <
  65                             (sk->sk_rcvbuf >> 1) &&
  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         if (sk)
  76                 bh_unlock_sock(sk);
  77
  78         ax25_start_heartbeat(ax25);
  79 }
  80
  81 void ax25_std_t2timer_expiry(ax25_cb *ax25)
  82 {
  83         if (ax25->condition & AX25_COND_ACK_PENDING) {
  84                 ax25->condition &= ~AX25_COND_ACK_PENDING;
  85                 ax25_std_timeout_response(ax25);
  86         }
  87 }
  88
  89 void ax25_std_t3timer_expiry(ax25_cb *ax25)
  90 {
  91         ax25->n2count = 0;
  92         ax25_std_transmit_enquiry(ax25);
  93         ax25->state   = AX25_STATE_4;
  94 }
  95
  96 void ax25_std_idletimer_expiry(ax25_cb *ax25)
  97 {
  98         ax25_clear_queues(ax25);
  99
 100         ax25->n2count = 0;
 101         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 102         ax25->state   = AX25_STATE_2;
 103
 104         ax25_calculate_t1(ax25);
 105         ax25_start_t1timer(ax25);
 106         ax25_stop_t2timer(ax25);
 107         ax25_stop_t3timer(ax25);
 108
 109         if (ax25->sk != NULL) {
 110                 bh_lock_sock(ax25->sk);
 111                 ax25->sk->sk_state     = TCP_CLOSE;
 112                 ax25->sk->sk_err       = 0;
 113                 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
 114                 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
 115                         ax25->sk->sk_state_change(ax25->sk);
 116                         sock_set_flag(ax25->sk, SOCK_DEAD);
 117                 }
 118                 bh_unlock_sock(ax25->sk);
 119         }
 120 }
 121
 122 void ax25_std_t1timer_expiry(ax25_cb *ax25)
 123 {
 124         switch (ax25->state) {
 125         case AX25_STATE_1:
 126                 if (ax25->n2count == ax25->n2) {
 127                         if (ax25->modulus == AX25_MODULUS) {
 128                                 ax25_disconnect(ax25, ETIMEDOUT);
 129                                 return;
 130                         } else {
 131                                 ax25->modulus = AX25_MODULUS;
 132                                 ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 133                                 ax25->n2count = 0;
 134                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 135                         }
 136                 } else {
 137                         ax25->n2count++;
 138                         if (ax25->modulus == AX25_MODULUS)
 139                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 140                         else
 141                                 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
 142                 }
 143                 break;
 144
 145         case AX25_STATE_2:
 146                 if (ax25->n2count == ax25->n2) {
 147                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 148                         ax25_disconnect(ax25, ETIMEDOUT);
 149                         return;
 150                 } else {
 151                         ax25->n2count++;
 152                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 153                 }
 154                 break;
 155
 156         case AX25_STATE_3:
 157                 ax25->n2count = 1;
 158                 ax25_std_transmit_enquiry(ax25);
 159                 ax25->state   = AX25_STATE_4;
 160                 break;
 161
 162         case AX25_STATE_4:
 163                 if (ax25->n2count == ax25->n2) {
 164                         ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 165                         ax25_disconnect(ax25, ETIMEDOUT);
 166                         return;
 167                 } else {
 168                         ax25->n2count++;
 169                         ax25_std_transmit_enquiry(ax25);
 170                 }
 171                 break;
 172         }
 173
 174         ax25_calculate_t1(ax25);
 175         ax25_start_t1timer(ax25);
 176 }