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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
8 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
9 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
10 * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
11 */
12#include <linux/errno.h>
13#include <linux/types.h>
14#include <linux/socket.h>
15#include <linux/in.h>
16#include <linux/kernel.h>
17#include <linux/timer.h>
18#include <linux/string.h>
19#include <linux/sockios.h>
20#include <linux/net.h>
21#include <net/ax25.h>
22#include <linux/inet.h>
23#include <linux/netdevice.h>
24#include <linux/skbuff.h>
25#include <net/sock.h>
26#include <net/tcp_states.h>
27#include <asm/uaccess.h>
28#include <asm/system.h>
29#include <linux/fcntl.h>
30#include <linux/mm.h>
31#include <linux/interrupt.h>
32
33void ax25_std_heartbeat_expiry(ax25_cb *ax25)
34{
35	struct sock *sk=ax25->sk;
36
37	if (sk)
38		bh_lock_sock(sk);
39
40	switch (ax25->state) {
41	case AX25_STATE_0:
42		/* Magic here: If we listen() and a new link dies before it
43		   is accepted() it isn't 'dead' so doesn't get removed. */
44		if (!sk || sock_flag(sk, SOCK_DESTROY) ||
45		    (sk->sk_state == TCP_LISTEN &&
46		     sock_flag(sk, SOCK_DEAD))) {
47			if (sk) {
48				sock_hold(sk);
49				ax25_destroy_socket(ax25);
50				bh_unlock_sock(sk);
51				sock_put(sk);
52			} else
53				ax25_destroy_socket(ax25);
54			return;
55		}
56		break;
57
58	case AX25_STATE_3:
59	case AX25_STATE_4:
60		/*
61		 * Check the state of the receive buffer.
62		 */
63		if (sk != NULL) {
64			if (atomic_read(&sk->sk_rmem_alloc) <
65			    (sk->sk_rcvbuf / 2) &&
66			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
67				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
68				ax25->condition &= ~AX25_COND_ACK_PENDING;
69				ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
70				break;
71			}
72		}
73	}
74
75	if (sk)
76		bh_unlock_sock(sk);
77
78	ax25_start_heartbeat(ax25);
79}
80
81void ax25_std_t2timer_expiry(ax25_cb *ax25)
82{
83	if (ax25->condition & AX25_COND_ACK_PENDING) {
84		ax25->condition &= ~AX25_COND_ACK_PENDING;
85		ax25_std_timeout_response(ax25);
86	}
87}
88
89void ax25_std_t3timer_expiry(ax25_cb *ax25)
90{
91	ax25->n2count = 0;
92	ax25_std_transmit_enquiry(ax25);
93	ax25->state   = AX25_STATE_4;
94}
95
96void ax25_std_idletimer_expiry(ax25_cb *ax25)
97{
98	ax25_clear_queues(ax25);
99
100	ax25->n2count = 0;
101	ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
102	ax25->state   = AX25_STATE_2;
103
104	ax25_calculate_t1(ax25);
105	ax25_start_t1timer(ax25);
106	ax25_stop_t2timer(ax25);
107	ax25_stop_t3timer(ax25);
108
109	if (ax25->sk != NULL) {
110		bh_lock_sock(ax25->sk);
111		ax25->sk->sk_state     = TCP_CLOSE;
112		ax25->sk->sk_err       = 0;
113		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
114		if (!sock_flag(ax25->sk, SOCK_DEAD)) {
115			ax25->sk->sk_state_change(ax25->sk);
116			sock_set_flag(ax25->sk, SOCK_DEAD);
117		}
118		bh_unlock_sock(ax25->sk);
119	}
120}
121
122void ax25_std_t1timer_expiry(ax25_cb *ax25)
123{
124	switch (ax25->state) {
125	case AX25_STATE_1:
126		if (ax25->n2count == ax25->n2) {
127			if (ax25->modulus == AX25_MODULUS) {
128				ax25_disconnect(ax25, ETIMEDOUT);
129				return;
130			} else {
131				ax25->modulus = AX25_MODULUS;
132				ax25->window  = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
133				ax25->n2count = 0;
134				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
135			}
136		} else {
137			ax25->n2count++;
138			if (ax25->modulus == AX25_MODULUS)
139				ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
140			else
141				ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
142		}
143		break;
144
145	case AX25_STATE_2:
146		if (ax25->n2count == ax25->n2) {
147			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
148			ax25_disconnect(ax25, ETIMEDOUT);
149			return;
150		} else {
151			ax25->n2count++;
152			ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
153		}
154		break;
155
156	case AX25_STATE_3:
157		ax25->n2count = 1;
158		ax25_std_transmit_enquiry(ax25);
159		ax25->state   = AX25_STATE_4;
160		break;
161
162	case AX25_STATE_4:
163		if (ax25->n2count == ax25->n2) {
164			ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
165			ax25_disconnect(ax25, ETIMEDOUT);
166			return;
167		} else {
168			ax25->n2count++;
169			ax25_std_transmit_enquiry(ax25);
170		}
171		break;
172	}
173
174	ax25_calculate_t1(ax25);
175	ax25_start_t1timer(ax25);
176}
177