LXR linux/net/lapb/lapb

   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 <linux/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(struct timer_list *);
  39static void lapb_t2timer_expiry(struct timer_list *);
  40
  41void lapb_start_t1timer(struct lapb_cb *lapb)
  42{
  43        del_timer(&lapb->t1timer);
  44
  45        lapb->t1timer.function = lapb_t1timer_expiry;
  46        lapb->t1timer.expires  = jiffies + lapb->t1;
  47
  48        add_timer(&lapb->t1timer);
  49}
  50
  51void lapb_start_t2timer(struct lapb_cb *lapb)
  52{
  53        del_timer(&lapb->t2timer);
  54
  55        lapb->t2timer.function = lapb_t2timer_expiry;
  56        lapb->t2timer.expires  = jiffies + lapb->t2;
  57
  58        add_timer(&lapb->t2timer);
  59}
  60
  61void lapb_stop_t1timer(struct lapb_cb *lapb)
  62{
  63        del_timer(&lapb->t1timer);
  64}
  65
  66void lapb_stop_t2timer(struct lapb_cb *lapb)
  67{
  68        del_timer(&lapb->t2timer);
  69}
  70
  71int lapb_t1timer_running(struct lapb_cb *lapb)
  72{
  73        return timer_pending(&lapb->t1timer);
  74}
  75
  76static void lapb_t2timer_expiry(struct timer_list *t)
  77{
  78        struct lapb_cb *lapb = from_timer(lapb, t, t2timer);
  79
  80        if (lapb->condition & LAPB_ACK_PENDING_CONDITION) {
  81                lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
  82                lapb_timeout_response(lapb);
  83        }
  84}
  85
  86static void lapb_t1timer_expiry(struct timer_list *t)
  87{
  88        struct lapb_cb *lapb = from_timer(lapb, t, t1timer);
  89
  90        switch (lapb->state) {
  91
  92                /*
  93                 *      If we are a DCE, keep going DM .. DM .. DM
  94                 */
  95                case LAPB_STATE_0:
  96                        if (lapb->mode & LAPB_DCE)
  97                                lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
  98                        break;
  99
 100                /*
 101                 *      Awaiting connection state, send SABM(E), up to N2 times.
 102                 */
 103                case LAPB_STATE_1:
 104                        if (lapb->n2count == lapb->n2) {
 105                                lapb_clear_queues(lapb);
 106                                lapb->state = LAPB_STATE_0;
 107                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 108                                lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
 109                                return;
 110                        } else {
 111                                lapb->n2count++;
 112                                if (lapb->mode & LAPB_EXTENDED) {
 113                                        lapb_dbg(1, "(%p) S1 TX SABME(1)\n",
 114                                                 lapb->dev);
 115                                        lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
 116                                } else {
 117                                        lapb_dbg(1, "(%p) S1 TX SABM(1)\n",
 118                                                 lapb->dev);
 119                                        lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
 120                                }
 121                        }
 122                        break;
 123
 124                /*
 125                 *      Awaiting disconnection state, send DISC, up to N2 times.
 126                 */
 127                case LAPB_STATE_2:
 128                        if (lapb->n2count == lapb->n2) {
 129                                lapb_clear_queues(lapb);
 130                                lapb->state = LAPB_STATE_0;
 131                                lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT);
 132                                lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
 133                                return;
 134                        } else {
 135                                lapb->n2count++;
 136                                lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev);
 137                                lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 138                        }
 139                        break;
 140
 141                /*
 142                 *      Data transfer state, restransmit I frames, up to N2 times.
 143                 */
 144                case LAPB_STATE_3:
 145                        if (lapb->n2count == lapb->n2) {
 146                                lapb_clear_queues(lapb);
 147                                lapb->state = LAPB_STATE_0;
 148                                lapb_stop_t2timer(lapb);
 149                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 150                                lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
 151                                return;
 152                        } else {
 153                                lapb->n2count++;
 154                                lapb_requeue_frames(lapb);
 155                                lapb_kick(lapb);
 156                        }
 157                        break;
 158
 159                /*
 160                 *      Frame reject state, restransmit FRMR frames, up to N2 times.
 161                 */
 162                case LAPB_STATE_4:
 163                        if (lapb->n2count == lapb->n2) {
 164                                lapb_clear_queues(lapb);
 165                                lapb->state = LAPB_STATE_0;
 166                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 167                                lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
 168                                return;
 169                        } else {
 170                                lapb->n2count++;
 171                                lapb_transmit_frmr(lapb);
 172                        }
 173                        break;
 174        }
 175
 176        lapb_start_t1timer(lapb);
 177}
 178