net/lapb/lapb_timer.c

   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
  33 static void lapb_t1timer_expiry(struct timer_list *);
  34 static void lapb_t2timer_expiry(struct timer_list *);
  35
  36 void 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
  46 void 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
  56 void lapb_stop_t1timer(struct lapb_cb *lapb)
  57 {
  58         del_timer(&lapb->t1timer);
  59 }
  60
  61 void lapb_stop_t2timer(struct lapb_cb *lapb)
  62 {
  63         del_timer(&lapb->t2timer);
  64 }
  65
  66 int lapb_t1timer_running(struct lapb_cb *lapb)
  67 {
  68         return timer_pending(&lapb->t1timer);
  69 }
  70
  71 static 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
  81 static 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, send DM up to N2 times, then switch to
  89                  *      STATE_1 and send SABM(E).
  90                  */
  91                 case LAPB_STATE_0:
  92                         if (lapb->mode & LAPB_DCE &&
  93                             lapb->n2count != lapb->n2) {
  94                                 lapb->n2count++;
  95                                 lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE);
  96                         } else {
  97                                 lapb->state = LAPB_STATE_1;
  98                                 lapb_establish_data_link(lapb);
  99                         }
 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                                 lapb_kick(lapb);
 158                         }
 159                         break;
 160
 161                 /*
 162                  *      Frame reject state, restransmit FRMR frames, up to N2 times.
 163                  */
 164                 case LAPB_STATE_4:
 165                         if (lapb->n2count == lapb->n2) {
 166                                 lapb_clear_queues(lapb);
 167                                 lapb->state = LAPB_STATE_0;
 168                                 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT);
 169                                 lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev);
 170                                 return;
 171                         } else {
 172                                 lapb->n2count++;
 173                                 lapb_transmit_frmr(lapb);
 174                         }
 175                         break;
 176         }
 177
 178         lapb_start_t1timer(lapb);
 179 }