linux/net/lapb/lapb_timer.c
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   1/*
   2 *      LAPB release 002
   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 *      LAPB 001        Jonathan Naylor Started Coding
  14 *      LAPB 002        Jonathan Naylor New timer architecture.
  15 */
  16
  17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  18
  19#include <linux/errno.h>
  20#include <linux/types.h>
  21#include <linux/socket.h>
  22#include <linux/in.h>
  23#include <linux/kernel.h>
  24#include <linux/jiffies.h>
  25#include <linux/timer.h>
  26#include <linux/string.h>
  27#include <linux/sockios.h>
  28#include <linux/net.h>
  29#include <linux/inet.h>
  30#include <linux/skbuff.h>
  31#include <net/sock.h>
  32#include <asm/uaccess.h>
  33#include <linux/fcntl.h>
  34#include <linux/mm.h>
  35#include <linux/interrupt.h>
  36#include <net/lapb.h>
  37
  38static void lapb_t1timer_expiry(unsigned long);
  39static void lapb_t2timer_expiry(unsigned long);
  40
  41void lapb_start_t1timer(struct lapb_cb *lapb)
  42{
  43        del_timer(&lapb->t1timer);
  44
  45        lapb->t1timer.data     = (unsigned long)lapb;
  46        lapb->t1timer.function = &lapb_t1timer_expiry;
  47        lapb->t1timer.expires  = jiffies + lapb->t1;
  48
  49        add_timer(&lapb->t1timer);
  50}
  51
  52void lapb_start_t2timer(struct lapb_cb *lapb)
  53{
  54        del_timer(&lapb->t2timer);
  55
  56        lapb->t2timer.data     = (unsigned long)lapb;
  57        lapb->t2timer.function = &lapb_t2timer_expiry;
  58        lapb->t2timer.expires  = jiffies + lapb->t2;
  59
  60        add_timer(&lapb->t2timer);
  61}
  62
  63void lapb_stop_t1timer(struct lapb_cb *lapb)
  64{
  65        del_timer(&lapb->t1timer);
  66}
  67
  68void lapb_stop_t2timer(struct lapb_cb *lapb)
  69{
  70        del_timer(&lapb->t2timer);
  71}
  72
  73int lapb_t1timer_running(struct lapb_cb *lapb)
  74{
  75        return timer_pending(&lapb->t1timer);
  76}
  77
  78static void lapb_t2timer_expiry(unsigned long param)
  79{
  80        struct lapb_cb *lapb = (struct lapb_cb *)param;
  81
  82        if (lapb->condition & LAPB_ACK_PENDING_CONDITION) {
  83                lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
  84                lapb_timeout_response(lapb);
  85        }
  86}
  87
  88static void lapb_t1timer_expiry(unsigned long param)
  89{
  90        struct lapb_cb *lapb = (struct lapb_cb *)param;
  91
  92        switch (lapb->state) {
  93
  94                /*
  95                 *      If we are a DCE, keep going DM .. DM .. DM
  96                 */
  97                case LAPB_STATE_0:
  98                        if (lapb->mode & LAPB_DCE)
  99                                lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
 100                        break;
 101
 102                /*
 103                 *      Awaiting connection state, send SABM(E), up to N2 times.
 104                 */
 105                case LAPB_STATE_1:
 106                        if (lapb->n2count == lapb->n2) {
 107                                lapb_clear_queues(lapb);
 108                                lapb->state = LAPB_STATE_0;
 109                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 110                                lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
 111                                return;
 112                        } else {
 113                                lapb->n2count++;
 114                                if (lapb->mode & LAPB_EXTENDED) {
 115                                        lapb_dbg(1, "(%p) S1 TX SABME(1)\n",
 116                                                 lapb->dev);
 117                                        lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
 118                                } else {
 119                                        lapb_dbg(1, "(%p) S1 TX SABM(1)\n",
 120                                                 lapb->dev);
 121                                        lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
 122                                }
 123                        }
 124                        break;
 125
 126                /*
 127                 *      Awaiting disconnection state, send DISC, up to N2 times.
 128                 */
 129                case LAPB_STATE_2:
 130                        if (lapb->n2count == lapb->n2) {
 131                                lapb_clear_queues(lapb);
 132                                lapb->state = LAPB_STATE_0;
 133                                lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT);
 134                                lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
 135                                return;
 136                        } else {
 137                                lapb->n2count++;
 138                                lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev);
 139                                lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 140                        }
 141                        break;
 142
 143                /*
 144                 *      Data transfer state, restransmit I frames, up to N2 times.
 145                 */
 146                case LAPB_STATE_3:
 147                        if (lapb->n2count == lapb->n2) {
 148                                lapb_clear_queues(lapb);
 149                                lapb->state = LAPB_STATE_0;
 150                                lapb_stop_t2timer(lapb);
 151                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 152                                lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
 153                                return;
 154                        } else {
 155                                lapb->n2count++;
 156                                lapb_requeue_frames(lapb);
 157                        }
 158                        break;
 159
 160                /*
 161                 *      Frame reject state, restransmit FRMR frames, up to N2 times.
 162                 */
 163                case LAPB_STATE_4:
 164                        if (lapb->n2count == lapb->n2) {
 165                                lapb_clear_queues(lapb);
 166                                lapb->state = LAPB_STATE_0;
 167                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 168                                lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
 169                                return;
 170                        } else {
 171                                lapb->n2count++;
 172                                lapb_transmit_frmr(lapb);
 173                        }
 174                        break;
 175        }
 176
 177        lapb_start_t1timer(lapb);
 178}
 179
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