net/ax25/ax25_std_subr.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   8  */
   9 #include <linux/errno.h>
  10 #include <linux/types.h>
  11 #include <linux/socket.h>
  12 #include <linux/in.h>
  13 #include <linux/kernel.h>
  14 #include <linux/timer.h>
  15 #include <linux/string.h>
  16 #include <linux/sockios.h>
  17 #include <linux/net.h>
  18 #include <net/ax25.h>
  19 #include <linux/inet.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/skbuff.h>
  22 #include <net/sock.h>
  23 #include <asm/uaccess.h>
  24 #include <linux/fcntl.h>
  25 #include <linux/mm.h>
  26 #include <linux/interrupt.h>
  27
  28 /*
  29  * The following routines are taken from page 170 of the 7th ARRL Computer
  30  * Networking Conference paper, as is the whole state machine.
  31  */
  32
  33 void ax25_std_nr_error_recovery(ax25_cb *ax25)
  34 {
  35         ax25_std_establish_data_link(ax25);
  36 }
  37
  38 void ax25_std_establish_data_link(ax25_cb *ax25)
  39 {
  40         ax25->condition = 0x00;
  41         ax25->n2count   = 0;
  42
  43         if (ax25->modulus == AX25_MODULUS)
  44                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
  45         else
  46                 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
  47
  48         ax25_calculate_t1(ax25);
  49         ax25_stop_idletimer(ax25);
  50         ax25_stop_t3timer(ax25);
  51         ax25_stop_t2timer(ax25);
  52         ax25_start_t1timer(ax25);
  53 }
  54
  55 void ax25_std_transmit_enquiry(ax25_cb *ax25)
  56 {
  57         if (ax25->condition & AX25_COND_OWN_RX_BUSY)
  58                 ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_COMMAND);
  59         else
  60                 ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_COMMAND);
  61
  62         ax25->condition &= ~AX25_COND_ACK_PENDING;
  63
  64         ax25_calculate_t1(ax25);
  65         ax25_start_t1timer(ax25);
  66 }
  67
  68 void ax25_std_enquiry_response(ax25_cb *ax25)
  69 {
  70         if (ax25->condition & AX25_COND_OWN_RX_BUSY)
  71                 ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_RESPONSE);
  72         else
  73                 ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_RESPONSE);
  74
  75         ax25->condition &= ~AX25_COND_ACK_PENDING;
  76 }
  77
  78 void ax25_std_timeout_response(ax25_cb *ax25)
  79 {
  80         if (ax25->condition & AX25_COND_OWN_RX_BUSY)
  81                 ax25_send_control(ax25, AX25_RNR, AX25_POLLOFF, AX25_RESPONSE);
  82         else
  83                 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
  84
  85         ax25->condition &= ~AX25_COND_ACK_PENDING;
  86 }