net/lapb/lapb_timer.c

   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
  38 static void lapb_t1timer_expiry(struct timer_list *);
  39 static void lapb_t2timer_expiry(struct timer_list *);
  40
  41 void 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
  51 void 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
  61 void lapb_stop_t1timer(struct lapb_cb *lapb)
  62 {
  63         del_timer(&lapb->t1timer);
  64 }
  65
  66 void lapb_stop_t2timer(struct lapb_cb *lapb)
  67 {
  68         del_timer(&lapb->t2timer);
  69 }
  70
  71 int lapb_t1timer_running(struct lapb_cb *lapb)
  72 {
  73         return timer_pending(&lapb->t1timer);
  74 }
  75
  76 static 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
  86 static 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 }