LXR linux/net/lapb/lapb

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *      LAPB release 002
   4 *
   5 *      This code REQUIRES 2.1.15 or higher/ NET3.038
   6 *
   7 *      History
   8 *      LAPB 001        Jonathan Naylor Started Coding
   9 *      LAPB 002        Jonathan Naylor New timer architecture.
  10 */
  11
  12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14#include <linux/errno.h>
  15#include <linux/types.h>
  16#include <linux/socket.h>
  17#include <linux/in.h>
  18#include <linux/kernel.h>
  19#include <linux/jiffies.h>
  20#include <linux/timer.h>
  21#include <linux/string.h>
  22#include <linux/sockios.h>
  23#include <linux/net.h>
  24#include <linux/inet.h>
  25#include <linux/skbuff.h>
  26#include <net/sock.h>
  27#include <linux/uaccess.h>
  28#include <linux/fcntl.h>
  29#include <linux/mm.h>
  30#include <linux/interrupt.h>
  31#include <net/lapb.h>
  32
  33static void lapb_t1timer_expiry(struct timer_list *);
  34static void lapb_t2timer_expiry(struct timer_list *);
  35
  36void lapb_start_t1timer(struct lapb_cb *lapb)
  37{
  38        del_timer(&lapb->t1timer);
  39
  40        lapb->t1timer.function = lapb_t1timer_expiry;
  41        lapb->t1timer.expires  = jiffies + lapb->t1;
  42
  43        add_timer(&lapb->t1timer);
  44}
  45
  46void lapb_start_t2timer(struct lapb_cb *lapb)
  47{
  48        del_timer(&lapb->t2timer);
  49
  50        lapb->t2timer.function = lapb_t2timer_expiry;
  51        lapb->t2timer.expires  = jiffies + lapb->t2;
  52
  53        add_timer(&lapb->t2timer);
  54}
  55
  56void lapb_stop_t1timer(struct lapb_cb *lapb)
  57{
  58        del_timer(&lapb->t1timer);
  59}
  60
  61void lapb_stop_t2timer(struct lapb_cb *lapb)
  62{
  63        del_timer(&lapb->t2timer);
  64}
  65
  66int lapb_t1timer_running(struct lapb_cb *lapb)
  67{
  68        return timer_pending(&lapb->t1timer);
  69}
  70
  71static void lapb_t2timer_expiry(struct timer_list *t)
  72{
  73        struct lapb_cb *lapb = from_timer(lapb, t, t2timer);
  74
  75        if (lapb->condition & LAPB_ACK_PENDING_CONDITION) {
  76                lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
  77                lapb_timeout_response(lapb);
  78        }
  79}
  80
  81static void lapb_t1timer_expiry(struct timer_list *t)
  82{
  83        struct lapb_cb *lapb = from_timer(lapb, t, t1timer);
  84
  85        switch (lapb->state) {
  86
  87                /*
  88                 *      If we are a DCE, keep going DM .. DM .. DM
  89                 */
  90                case LAPB_STATE_0:
  91                        if (lapb->mode & LAPB_DCE)
  92                                lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
  93                        break;
  94
  95                /*
  96                 *      Awaiting connection state, send SABM(E), up to N2 times.
  97                 */
  98                case LAPB_STATE_1:
  99                        if (lapb->n2count == lapb->n2) {
 100                                lapb_clear_queues(lapb);
 101                                lapb->state = LAPB_STATE_0;
 102                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 103                                lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
 104                                return;
 105                        } else {
 106                                lapb->n2count++;
 107                                if (lapb->mode & LAPB_EXTENDED) {
 108                                        lapb_dbg(1, "(%p) S1 TX SABME(1)\n",
 109                                                 lapb->dev);
 110                                        lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
 111                                } else {
 112                                        lapb_dbg(1, "(%p) S1 TX SABM(1)\n",
 113                                                 lapb->dev);
 114                                        lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
 115                                }
 116                        }
 117                        break;
 118
 119                /*
 120                 *      Awaiting disconnection state, send DISC, up to N2 times.
 121                 */
 122                case LAPB_STATE_2:
 123                        if (lapb->n2count == lapb->n2) {
 124                                lapb_clear_queues(lapb);
 125                                lapb->state = LAPB_STATE_0;
 126                                lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT);
 127                                lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev);
 128                                return;
 129                        } else {
 130                                lapb->n2count++;
 131                                lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev);
 132                                lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
 133                        }
 134                        break;
 135
 136                /*
 137                 *      Data transfer state, restransmit I frames, up to N2 times.
 138                 */
 139                case LAPB_STATE_3:
 140                        if (lapb->n2count == lapb->n2) {
 141                                lapb_clear_queues(lapb);
 142                                lapb->state = LAPB_STATE_0;
 143                                lapb_stop_t2timer(lapb);
 144                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 145                                lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev);
 146                                return;
 147                        } else {
 148                                lapb->n2count++;
 149                                lapb_requeue_frames(lapb);
 150                                lapb_kick(lapb);
 151                        }
 152                        break;
 153
 154                /*
 155                 *      Frame reject state, restransmit FRMR frames, up to N2 times.
 156                 */
 157                case LAPB_STATE_4:
 158                        if (lapb->n2count == lapb->n2) {
 159                                lapb_clear_queues(lapb);
 160                                lapb->state = LAPB_STATE_0;
 161                                lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 162                                lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
 163                                return;
 164                        } else {
 165                                lapb->n2count++;
 166                                lapb_transmit_frmr(lapb);
 167                        }
 168                        break;
 169        }
 170
 171        lapb_start_t1timer(lapb);
 172}
 173