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
30void ax25_std_nr_error_recovery(ax25_cb *ax25)
31{
32 ax25_std_establish_data_link(ax25);
33}
34
35void 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
52void 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
65void 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
75void 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}
84

source code of linux/net/ax25/ax25_std_subr.c