net/x25/x25_timer.c

   1 /*
   2  *      X.25 Packet Layer release 002
   3  *
   4  *      This is ALPHA test software. This code may break your machine, randomly fail to work with new
   5  *      releases, misbehave and/or generally screw up. It might even work.
   6  *
   7  *      This code REQUIRES 2.1.15 or higher
   8  *
   9  *      This module:
  10  *              This module is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or (at your option) any later version.
  14  *
  15  *      History
  16  *      X.25 001        Jonathan Naylor Started coding.
  17  *      X.25 002        Jonathan Naylor New timer architecture.
  18  *                                      Centralised disconnection processing.
  19  */
  20
  21 #include <linux/config.h>
  22 #if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE)
  23 #include <linux/errno.h>
  24 #include <linux/types.h>
  25 #include <linux/socket.h>
  26 #include <linux/in.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched.h>
  29 #include <linux/timer.h>
  30 #include <linux/string.h>
  31 #include <linux/sockios.h>
  32 #include <linux/net.h>
  33 #include <linux/inet.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/skbuff.h>
  36 #include <net/sock.h>
  37 #include <asm/segment.h>
  38 #include <asm/system.h>
  39 #include <linux/fcntl.h>
  40 #include <linux/mm.h>
  41 #include <linux/interrupt.h>
  42 #include <net/x25.h>
  43
  44 static void x25_heartbeat_expiry(unsigned long);
  45 static void x25_timer_expiry(unsigned long);
  46
  47 void x25_start_heartbeat(struct sock *sk)
  48 {
  49         del_timer(&sk->timer);
  50
  51         sk->timer.data     = (unsigned long)sk;
  52         sk->timer.function = &x25_heartbeat_expiry;
  53         sk->timer.expires  = jiffies + 5 * HZ;
  54
  55         add_timer(&sk->timer);
  56 }
  57
  58 void x25_stop_heartbeat(struct sock *sk)
  59 {
  60         del_timer(&sk->timer);
  61 }
  62
  63 void x25_start_t2timer(struct sock *sk)
  64 {
  65         del_timer(&sk->protinfo.x25->timer);
  66
  67         sk->protinfo.x25->timer.data     = (unsigned long)sk;
  68         sk->protinfo.x25->timer.function = &x25_timer_expiry;
  69         sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t2;
  70
  71         add_timer(&sk->protinfo.x25->timer);
  72 }
  73
  74 void x25_start_t21timer(struct sock *sk)
  75 {
  76         del_timer(&sk->protinfo.x25->timer);
  77
  78         sk->protinfo.x25->timer.data     = (unsigned long)sk;
  79         sk->protinfo.x25->timer.function = &x25_timer_expiry;
  80         sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t21;
  81
  82         add_timer(&sk->protinfo.x25->timer);
  83 }
  84
  85 void x25_start_t22timer(struct sock *sk)
  86 {
  87         del_timer(&sk->protinfo.x25->timer);
  88
  89         sk->protinfo.x25->timer.data     = (unsigned long)sk;
  90         sk->protinfo.x25->timer.function = &x25_timer_expiry;
  91         sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t22;
  92
  93         add_timer(&sk->protinfo.x25->timer);
  94 }
  95
  96 void x25_start_t23timer(struct sock *sk)
  97 {
  98         del_timer(&sk->protinfo.x25->timer);
  99
 100         sk->protinfo.x25->timer.data     = (unsigned long)sk;
 101         sk->protinfo.x25->timer.function = &x25_timer_expiry;
 102         sk->protinfo.x25->timer.expires  = jiffies + sk->protinfo.x25->t23;
 103
 104         add_timer(&sk->protinfo.x25->timer);
 105 }
 106
 107 void x25_stop_timer(struct sock *sk)
 108 {
 109         del_timer(&sk->protinfo.x25->timer);
 110 }
 111
 112 unsigned long x25_display_timer(struct sock *sk)
 113 {
 114         if (!timer_pending(&sk->protinfo.x25->timer))
 115                 return 0;
 116
 117         return sk->protinfo.x25->timer.expires - jiffies;
 118 }
 119
 120 static void x25_heartbeat_expiry(unsigned long param)
 121 {
 122         struct sock *sk = (struct sock *)param;
 123
 124         switch (sk->protinfo.x25->state) {
 125
 126                 case X25_STATE_0:
 127                         /* Magic here: If we listen() and a new link dies before it
 128                            is accepted() it isn't 'dead' so doesn't get removed. */
 129                         if (sk->destroy || (sk->state == TCP_LISTEN && sk->dead)) {
 130                                 x25_destroy_socket(sk);
 131                                 return;
 132                         }
 133                         break;
 134
 135                 case X25_STATE_3:
 136                         /*
 137                          * Check for the state of the receive buffer.
 138                          */
 139                         if (atomic_read(&sk->rmem_alloc) < (sk->rcvbuf / 2) &&
 140                             (sk->protinfo.x25->condition & X25_COND_OWN_RX_BUSY)) {
 141                                 sk->protinfo.x25->condition &= ~X25_COND_OWN_RX_BUSY;
 142                                 sk->protinfo.x25->condition &= ~X25_COND_ACK_PENDING;
 143                                 sk->protinfo.x25->vl         = sk->protinfo.x25->vr;
 144                                 x25_write_internal(sk, X25_RR);
 145                                 x25_stop_timer(sk);
 146                                 break;
 147                         }
 148                         break;
 149         }
 150
 151         x25_start_heartbeat(sk);
 152 }
 153
 154 /*
 155  *      Timer has expired, it may have been T2, T21, T22, or T23. We can tell
 156  *      by the state machine state.
 157  */
 158 static void x25_timer_expiry(unsigned long param)
 159 {
 160         struct sock *sk = (struct sock *)param;
 161
 162         switch (sk->protinfo.x25->state) {
 163
 164                 case X25_STATE_3:       /* T2 */
 165                         if (sk->protinfo.x25->condition & X25_COND_ACK_PENDING) {
 166                                 sk->protinfo.x25->condition &= ~X25_COND_ACK_PENDING;
 167                                 x25_enquiry_response(sk);
 168                         }
 169                         break;
 170
 171                 case X25_STATE_1:       /* T21 */
 172                 case X25_STATE_4:       /* T22 */
 173                         x25_write_internal(sk, X25_CLEAR_REQUEST);
 174                         sk->protinfo.x25->state = X25_STATE_2;
 175                         x25_start_t23timer(sk);
 176                         break;
 177
 178                 case X25_STATE_2:       /* T23 */
 179                         x25_disconnect(sk, ETIMEDOUT, 0, 0);
 180                         break;
 181         }
 182 }
 183
 184 #endif