net/ax25/ax25_std_subr.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   5  */
   6 #include <linux/errno.h>
   7 #include <linux/types.h>
   8 #include <linux/socket.h>
   9 #include <linux/in.h>
  10 #include <linux/kernel.h>
  11 #include <linux/timer.h>
  12 #include <linux/string.h>
  13 #include <linux/sockios.h>
  14 #include <linux/net.h>
  15 #include <net/ax25.h>
  16 #include <linux/inet.h>
  17 #include <linux/netdevice.h>
  18 #include <linux/skbuff.h>
  19 #include <net/sock.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/fcntl.h>
  22 #include <linux/mm.h>
  23 #include <linux/interrupt.h>
  24
  25 /*
  26  * The following routines are taken from page 170 of the 7th ARRL Computer
  27  * Networking Conference paper, as is the whole state machine.
  28  */
  29
  30 void ax25_std_nr_error_recovery(ax25_cb *ax25)
  31 {
  32         ax25_std_establish_data_link(ax25);
  33 }
  34
  35 void ax25_std_establish_data_link(ax25_cb *ax25)
  36 {
  37         ax25->condition = 0x00;
  38         ax25->n2count   = 0;
  39
  40         if (ax25->modulus == AX25_MODULUS)
  41                 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
  42         else
  43                 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
  44
  45         ax25_calculate_t1(ax25);
  46         ax25_stop_idletimer(ax25);
  47         ax25_stop_t3timer(ax25);
  48         ax25_stop_t2timer(ax25);
  49         ax25_start_t1timer(ax25);
  50 }
  51
  52 void ax25_std_transmit_enquiry(ax25_cb *ax25)
  53 {
  54         if (ax25->condition & AX25_COND_OWN_RX_BUSY)
  55                 ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_COMMAND);
  56         else
  57                 ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_COMMAND);
  58
  59         ax25->condition &= ~AX25_COND_ACK_PENDING;
  60
  61         ax25_calculate_t1(ax25);
  62         ax25_start_t1timer(ax25);
  63 }
  64
  65 void ax25_std_enquiry_response(ax25_cb *ax25)
  66 {
  67         if (ax25->condition & AX25_COND_OWN_RX_BUSY)
  68                 ax25_send_control(ax25, AX25_RNR, AX25_POLLON, AX25_RESPONSE);
  69         else
  70                 ax25_send_control(ax25, AX25_RR, AX25_POLLON, AX25_RESPONSE);
  71
  72         ax25->condition &= ~AX25_COND_ACK_PENDING;
  73 }
  74
  75 void ax25_std_timeout_response(ax25_cb *ax25)
  76 {
  77         if (ax25->condition & AX25_COND_OWN_RX_BUSY)
  78                 ax25_send_control(ax25, AX25_RNR, AX25_POLLOFF, AX25_RESPONSE);
  79         else
  80                 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
  81
  82         ax25->condition &= ~AX25_COND_ACK_PENDING;
  83 }