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 * Copyright (C) 2002 Ralf Baechle DO1GRB (ralf@gnu.org)
9 */
10#include <linux/errno.h>
11#include <linux/types.h>
12#include <linux/socket.h>
13#include <linux/in.h>
14#include <linux/kernel.h>
15#include <linux/jiffies.h>
16#include <linux/timer.h>
17#include <linux/string.h>
18#include <linux/sockios.h>
19#include <linux/net.h>
20#include <net/ax25.h>
21#include <linux/inet.h>
22#include <linux/netdevice.h>
23#include <linux/skbuff.h>
24#include <net/sock.h>
25#include <net/tcp_states.h>
26#include <asm/uaccess.h>
27#include <asm/system.h>
28#include <linux/fcntl.h>
29#include <linux/mm.h>
30#include <linux/interrupt.h>
31#include <net/netrom.h>
32
33static void nr_heartbeat_expiry(unsigned long);
34static void nr_t1timer_expiry(unsigned long);
35static void nr_t2timer_expiry(unsigned long);
36static void nr_t4timer_expiry(unsigned long);
37static void nr_idletimer_expiry(unsigned long);
38
39void nr_init_timers(struct sock *sk)
40{
41	struct nr_sock *nr = nr_sk(sk);
42
43	init_timer(&nr->t1timer);
44	nr->t1timer.data     = (unsigned long)sk;
45	nr->t1timer.function = &nr_t1timer_expiry;
46
47	init_timer(&nr->t2timer);
48	nr->t2timer.data     = (unsigned long)sk;
49	nr->t2timer.function = &nr_t2timer_expiry;
50
51	init_timer(&nr->t4timer);
52	nr->t4timer.data     = (unsigned long)sk;
53	nr->t4timer.function = &nr_t4timer_expiry;
54
55	init_timer(&nr->idletimer);
56	nr->idletimer.data     = (unsigned long)sk;
57	nr->idletimer.function = &nr_idletimer_expiry;
58
59	/* initialized by sock_init_data */
60	sk->sk_timer.data     = (unsigned long)sk;
61	sk->sk_timer.function = &nr_heartbeat_expiry;
62}
63
64void nr_start_t1timer(struct sock *sk)
65{
66	struct nr_sock *nr = nr_sk(sk);
67
68	mod_timer(&nr->t1timer, jiffies + nr->t1);
69}
70
71void nr_start_t2timer(struct sock *sk)
72{
73	struct nr_sock *nr = nr_sk(sk);
74
75	mod_timer(&nr->t2timer, jiffies + nr->t2);
76}
77
78void nr_start_t4timer(struct sock *sk)
79{
80	struct nr_sock *nr = nr_sk(sk);
81
82	mod_timer(&nr->t4timer, jiffies + nr->t4);
83}
84
85void nr_start_idletimer(struct sock *sk)
86{
87	struct nr_sock *nr = nr_sk(sk);
88
89	if (nr->idle > 0)
90		mod_timer(&nr->idletimer, jiffies + nr->idle);
91}
92
93void nr_start_heartbeat(struct sock *sk)
94{
95	mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
96}
97
98void nr_stop_t1timer(struct sock *sk)
99{
100	del_timer(&nr_sk(sk)->t1timer);
101}
102
103void nr_stop_t2timer(struct sock *sk)
104{
105	del_timer(&nr_sk(sk)->t2timer);
106}
107
108void nr_stop_t4timer(struct sock *sk)
109{
110	del_timer(&nr_sk(sk)->t4timer);
111}
112
113void nr_stop_idletimer(struct sock *sk)
114{
115	del_timer(&nr_sk(sk)->idletimer);
116}
117
118void nr_stop_heartbeat(struct sock *sk)
119{
120	del_timer(&sk->sk_timer);
121}
122
123int nr_t1timer_running(struct sock *sk)
124{
125	return timer_pending(&nr_sk(sk)->t1timer);
126}
127
128static void nr_heartbeat_expiry(unsigned long param)
129{
130	struct sock *sk = (struct sock *)param;
131	struct nr_sock *nr = nr_sk(sk);
132
133	bh_lock_sock(sk);
134	switch (nr->state) {
135	case NR_STATE_0:
136		/* Magic here: If we listen() and a new link dies before it
137		   is accepted() it isn't 'dead' so doesn't get removed. */
138		if (sock_flag(sk, SOCK_DESTROY) ||
139		    (sk->sk_state == TCP_LISTEN && sock_flag(sk, SOCK_DEAD))) {
140			sock_hold(sk);
141			bh_unlock_sock(sk);
142			nr_destroy_socket(sk);
143			sock_put(sk);
144			return;
145		}
146		break;
147
148	case NR_STATE_3:
149		/*
150		 * Check for the state of the receive buffer.
151		 */
152		if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
153		    (nr->condition & NR_COND_OWN_RX_BUSY)) {
154			nr->condition &= ~NR_COND_OWN_RX_BUSY;
155			nr->condition &= ~NR_COND_ACK_PENDING;
156			nr->vl         = nr->vr;
157			nr_write_internal(sk, NR_INFOACK);
158			break;
159		}
160		break;
161	}
162
163	nr_start_heartbeat(sk);
164	bh_unlock_sock(sk);
165}
166
167static void nr_t2timer_expiry(unsigned long param)
168{
169	struct sock *sk = (struct sock *)param;
170	struct nr_sock *nr = nr_sk(sk);
171
172	bh_lock_sock(sk);
173	if (nr->condition & NR_COND_ACK_PENDING) {
174		nr->condition &= ~NR_COND_ACK_PENDING;
175		nr_enquiry_response(sk);
176	}
177	bh_unlock_sock(sk);
178}
179
180static void nr_t4timer_expiry(unsigned long param)
181{
182	struct sock *sk = (struct sock *)param;
183
184	bh_lock_sock(sk);
185	nr_sk(sk)->condition &= ~NR_COND_PEER_RX_BUSY;
186	bh_unlock_sock(sk);
187}
188
189static void nr_idletimer_expiry(unsigned long param)
190{
191	struct sock *sk = (struct sock *)param;
192	struct nr_sock *nr = nr_sk(sk);
193
194	bh_lock_sock(sk);
195
196	nr_clear_queues(sk);
197
198	nr->n2count = 0;
199	nr_write_internal(sk, NR_DISCREQ);
200	nr->state = NR_STATE_2;
201
202	nr_start_t1timer(sk);
203	nr_stop_t2timer(sk);
204	nr_stop_t4timer(sk);
205
206	sk->sk_state     = TCP_CLOSE;
207	sk->sk_err       = 0;
208	sk->sk_shutdown |= SEND_SHUTDOWN;
209
210	if (!sock_flag(sk, SOCK_DEAD)) {
211		sk->sk_state_change(sk);
212		sock_set_flag(sk, SOCK_DEAD);
213	}
214	bh_unlock_sock(sk);
215}
216
217static void nr_t1timer_expiry(unsigned long param)
218{
219	struct sock *sk = (struct sock *)param;
220	struct nr_sock *nr = nr_sk(sk);
221
222	bh_lock_sock(sk);
223	switch (nr->state) {
224	case NR_STATE_1:
225		if (nr->n2count == nr->n2) {
226			nr_disconnect(sk, ETIMEDOUT);
227			bh_unlock_sock(sk);
228			return;
229		} else {
230			nr->n2count++;
231			nr_write_internal(sk, NR_CONNREQ);
232		}
233		break;
234
235	case NR_STATE_2:
236		if (nr->n2count == nr->n2) {
237			nr_disconnect(sk, ETIMEDOUT);
238			bh_unlock_sock(sk);
239			return;
240		} else {
241			nr->n2count++;
242			nr_write_internal(sk, NR_DISCREQ);
243		}
244		break;
245
246	case NR_STATE_3:
247		if (nr->n2count == nr->n2) {
248			nr_disconnect(sk, ETIMEDOUT);
249			bh_unlock_sock(sk);
250			return;
251		} else {
252			nr->n2count++;
253			nr_requeue_frames(sk);
254		}
255		break;
256	}
257
258	nr_start_t1timer(sk);
259	bh_unlock_sock(sk);
260}
261