kernel/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 <linux/fcntl.h>
  29 #include <linux/mm.h>
  30 #include <linux/interrupt.h>
  31
  32 void ax25_std_heartbeat_expiry(ax25_cb *ax25)
  33 {
  34         struct sock *sk = ax25->sk;
  35
  36         if (sk)
  37                 bh_lock_sock(sk);
  38
  39         switch (ax25->state) {
  40         case AX25_STATE_0:
  41                 /* Magic here: If we listen() and a new link dies before it
  42                    is accepted() it isn't 'dead' so doesn't get removed. */
  43                 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
  44                     (sk->sk_state == TCP_LISTEN &&
  45                      sock_flag(sk, SOCK_DEAD))) {
  46                         if (sk) {
  47                                 sock_hold(sk);
  48                                 ax25_destroy_socket(ax25);
  49                                 bh_unlock_sock(sk);
  50                                 sock_put(sk);
  51                         } else
  52                                 ax25_destroy_socket(ax25);
  53                         return;
  54                 }
  55                 break;
  56
  57         case AX25_STATE_3:
  58         case AX25_STATE_4:
  59                 /*
  60                  * Check the state of the receive buffer.
  61                  */
  62                 if (sk != NULL) {
  63                         if (atomic_read(&sk->sk_rmem_alloc) <
  64                             (sk->sk_rcvbuf >> 1) &&
  65                             (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
  66                                 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
  67                                 ax25->condition &= ~AX25_COND_ACK_PENDING;
  68                                 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
  69                                 break;
  70                         }
  71                 }
  72         }
  73
  74         if (sk)
  75                 bh_unlock_sock(sk);
  76
  77         ax25_start_heartbeat(ax25);
  78 }
  79
  80 void ax25_std_t2timer_expiry(ax25_cb *ax25)
  81 {
  82         if (ax25->condition & AX25_COND_ACK_PENDING) {
  83                 ax25->condition &= ~AX25_COND_ACK_PENDING;
  84                 ax25_std_timeout_response(ax25);
  85         }
  86 }
  87
  88 void ax25_std_t3timer_expiry(ax25_cb *ax25)
  89 {
  90         ax25->n2count = 0;
  91         ax25_std_transmit_enquiry(ax25);
  92         ax25->state   = AX25_STATE_4;
  93 }
  94
  95 void ax25_std_idletimer_expiry(ax25_cb *ax25)
  96 {
  97         ax25_clear_queues(ax25);
  98
  99         ax25->n2count = 0;
 100         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 101         ax25->state   = AX25_STATE_2;
 102
 103         ax25_calculate_t1(ax25);
 104         ax25_start_t1timer(ax25);
 105         ax25_stop_t2timer(ax25);
 106         ax25_stop_t3timer(ax25);
 107
 108         if (ax25->sk != NULL) {
 109                 bh_lock_sock(ax25->sk);
 110                 ax25->sk->sk_state     = TCP_CLOSE;
 111                 ax25->sk->sk_err       = 0;
 112                 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
 113                 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
 114                         ax25->sk->sk_state_change(ax25->sk);
 115                         sock_set_flag(ax25->sk, SOCK_DEAD);
 116                 }
 117                 bh_unlock_sock(ax25->sk);
 118         }
 119 }
 120
 121 void ax25_std_t1timer_expiry(ax25_cb *ax25)
 122 {
 123         switch (ax25->state) {
 124         case AX25_STATE_1:
 125                 if (ax25->n2count == ax25->n2) {
 126                         if (ax25->modulus == AX25_MODULUS) {
 127                                 ax25_disconnect(ax25, ETIMEDOUT);
 128                                 return;
 129                         } else {
 130                                 ax25->modulus = AX25_MODULUS;
 131                                 ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 132                                 ax25->n2count = 0;
 133                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 134                         }
 135                 } else {
 136                         ax25->n2count++;
 137                         if (ax25->modulus == AX25_MODULUS)
 138                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 139                         else
 140                                 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
 141                 }
 142                 break;
 143
 144         case AX25_STATE_2:
 145                 if (ax25->n2count == ax25->n2) {
 146                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 147                         ax25_disconnect(ax25, ETIMEDOUT);
 148                         return;
 149                 } else {
 150                         ax25->n2count++;
 151                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 152                 }
 153                 break;
 154
 155         case AX25_STATE_3:
 156                 ax25->n2count = 1;
 157                 ax25_std_transmit_enquiry(ax25);
 158                 ax25->state   = AX25_STATE_4;
 159                 break;
 160
 161         case AX25_STATE_4:
 162                 if (ax25->n2count == ax25->n2) {
 163                         ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 164                         ax25_disconnect(ax25, ETIMEDOUT);
 165                         return;
 166                 } else {
 167                         ax25->n2count++;
 168                         ax25_std_transmit_enquiry(ax25);
 169                 }
 170                 break;
 171         }
 172
 173         ax25_calculate_t1(ax25);
 174         ax25_start_t1timer(ax25);
 175 }