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 <linux/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         case AX25_STATE_2:
  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                                 /* Ungrab socket and destroy it */
  52                                 sock_put(sk);
  53                         } else
  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 (sk != NULL) {
  65                         if (atomic_read(&sk->sk_rmem_alloc) <
  66                             (sk->sk_rcvbuf >> 1) &&
  67                             (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
  68                                 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
  69                                 ax25->condition &= ~AX25_COND_ACK_PENDING;
  70                                 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
  71                                 break;
  72                         }
  73                 }
  74         }
  75
  76         if (sk)
  77                 bh_unlock_sock(sk);
  78
  79         ax25_start_heartbeat(ax25);
  80 }
  81
  82 void ax25_std_t2timer_expiry(ax25_cb *ax25)
  83 {
  84         if (ax25->condition & AX25_COND_ACK_PENDING) {
  85                 ax25->condition &= ~AX25_COND_ACK_PENDING;
  86                 ax25_std_timeout_response(ax25);
  87         }
  88 }
  89
  90 void ax25_std_t3timer_expiry(ax25_cb *ax25)
  91 {
  92         ax25->n2count = 0;
  93         ax25_std_transmit_enquiry(ax25);
  94         ax25->state   = AX25_STATE_4;
  95 }
  96
  97 void ax25_std_idletimer_expiry(ax25_cb *ax25)
  98 {
  99         ax25_clear_queues(ax25);
 100
 101         ax25->n2count = 0;
 102         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 103         ax25->state   = AX25_STATE_2;
 104
 105         ax25_calculate_t1(ax25);
 106         ax25_start_t1timer(ax25);
 107         ax25_stop_t2timer(ax25);
 108         ax25_stop_t3timer(ax25);
 109
 110         if (ax25->sk != NULL) {
 111                 bh_lock_sock(ax25->sk);
 112                 ax25->sk->sk_state     = TCP_CLOSE;
 113                 ax25->sk->sk_err       = 0;
 114                 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
 115                 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
 116                         ax25->sk->sk_state_change(ax25->sk);
 117                         sock_set_flag(ax25->sk, SOCK_DEAD);
 118                 }
 119                 bh_unlock_sock(ax25->sk);
 120         }
 121 }
 122
 123 void ax25_std_t1timer_expiry(ax25_cb *ax25)
 124 {
 125         switch (ax25->state) {
 126         case AX25_STATE_1:
 127                 if (ax25->n2count == ax25->n2) {
 128                         if (ax25->modulus == AX25_MODULUS) {
 129                                 ax25_disconnect(ax25, ETIMEDOUT);
 130                                 return;
 131                         } else {
 132                                 ax25->modulus = AX25_MODULUS;
 133                                 ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
 134                                 ax25->n2count = 0;
 135                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 136                         }
 137                 } else {
 138                         ax25->n2count++;
 139                         if (ax25->modulus == AX25_MODULUS)
 140                                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
 141                         else
 142                                 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
 143                 }
 144                 break;
 145
 146         case AX25_STATE_2:
 147                 if (ax25->n2count == ax25->n2) {
 148                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 149                         if (!sock_flag(ax25->sk, SOCK_DESTROY))
 150                                 ax25_disconnect(ax25, ETIMEDOUT);
 151                         return;
 152                 } else {
 153                         ax25->n2count++;
 154                         ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
 155                 }
 156                 break;
 157
 158         case AX25_STATE_3:
 159                 ax25->n2count = 1;
 160                 ax25_std_transmit_enquiry(ax25);
 161                 ax25->state   = AX25_STATE_4;
 162                 break;
 163
 164         case AX25_STATE_4:
 165                 if (ax25->n2count == ax25->n2) {
 166                         ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
 167                         ax25_disconnect(ax25, ETIMEDOUT);
 168                         return;
 169                 } else {
 170                         ax25->n2count++;
 171                         ax25_std_transmit_enquiry(ax25);
 172                 }
 173                 break;
 174         }
 175
 176         ax25_calculate_t1(ax25);
 177         ax25_start_t1timer(ax25);
 178 }