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	setup_timer(&nr->t1timer, nr_t1timer_expiry, (unsigned long)sk);
44	setup_timer(&nr->t2timer, nr_t2timer_expiry, (unsigned long)sk);
45	setup_timer(&nr->t4timer, nr_t4timer_expiry, (unsigned long)sk);
46	setup_timer(&nr->idletimer, nr_idletimer_expiry, (unsigned long)sk);
47
48	/* initialized by sock_init_data */
49	sk->sk_timer.data     = (unsigned long)sk;
50	sk->sk_timer.function = &nr_heartbeat_expiry;
51}
52
53void nr_start_t1timer(struct sock *sk)
54{
55	struct nr_sock *nr = nr_sk(sk);
56
57	mod_timer(&nr->t1timer, jiffies + nr->t1);
58}
59
60void nr_start_t2timer(struct sock *sk)
61{
62	struct nr_sock *nr = nr_sk(sk);
63
64	mod_timer(&nr->t2timer, jiffies + nr->t2);
65}
66
67void nr_start_t4timer(struct sock *sk)
68{
69	struct nr_sock *nr = nr_sk(sk);
70
71	mod_timer(&nr->t4timer, jiffies + nr->t4);
72}
73
74void nr_start_idletimer(struct sock *sk)
75{
76	struct nr_sock *nr = nr_sk(sk);
77
78	if (nr->idle > 0)
79		mod_timer(&nr->idletimer, jiffies + nr->idle);
80}
81
82void nr_start_heartbeat(struct sock *sk)
83{
84	mod_timer(&sk->sk_timer, jiffies + 5 * HZ);
85}
86
87void nr_stop_t1timer(struct sock *sk)
88{
89	del_timer(&nr_sk(sk)->t1timer);
90}
91
92void nr_stop_t2timer(struct sock *sk)
93{
94	del_timer(&nr_sk(sk)->t2timer);
95}
96
97void nr_stop_t4timer(struct sock *sk)
98{
99	del_timer(&nr_sk(sk)->t4timer);
100}
101
102void nr_stop_idletimer(struct sock *sk)
103{
104	del_timer(&nr_sk(sk)->idletimer);
105}
106
107void nr_stop_heartbeat(struct sock *sk)
108{
109	del_timer(&sk->sk_timer);
110}
111
112int nr_t1timer_running(struct sock *sk)
113{
114	return timer_pending(&nr_sk(sk)->t1timer);
115}
116
117static void nr_heartbeat_expiry(unsigned long param)
118{
119	struct sock *sk = (struct sock *)param;
120	struct nr_sock *nr = nr_sk(sk);
121
122	bh_lock_sock(sk);
123	switch (nr->state) {
124	case NR_STATE_0:
125		/* Magic here: If we listen() and a new link dies before it
126		   is accepted() it isn't 'dead' so doesn't get removed. */
127		if (sock_flag(sk, SOCK_DESTROY) ||
128		    (sk->sk_state == TCP_LISTEN && sock_flag(sk, SOCK_DEAD))) {
129			sock_hold(sk);
130			bh_unlock_sock(sk);
131			nr_destroy_socket(sk);
132			sock_put(sk);
133			return;
134		}
135		break;
136
137	case NR_STATE_3:
138		/*
139		 * Check for the state of the receive buffer.
140		 */
141		if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
142		    (nr->condition & NR_COND_OWN_RX_BUSY)) {
143			nr->condition &= ~NR_COND_OWN_RX_BUSY;
144			nr->condition &= ~NR_COND_ACK_PENDING;
145			nr->vl         = nr->vr;
146			nr_write_internal(sk, NR_INFOACK);
147			break;
148		}
149		break;
150	}
151
152	nr_start_heartbeat(sk);
153	bh_unlock_sock(sk);
154}
155
156static void nr_t2timer_expiry(unsigned long param)
157{
158	struct sock *sk = (struct sock *)param;
159	struct nr_sock *nr = nr_sk(sk);
160
161	bh_lock_sock(sk);
162	if (nr->condition & NR_COND_ACK_PENDING) {
163		nr->condition &= ~NR_COND_ACK_PENDING;
164		nr_enquiry_response(sk);
165	}
166	bh_unlock_sock(sk);
167}
168
169static void nr_t4timer_expiry(unsigned long param)
170{
171	struct sock *sk = (struct sock *)param;
172
173	bh_lock_sock(sk);
174	nr_sk(sk)->condition &= ~NR_COND_PEER_RX_BUSY;
175	bh_unlock_sock(sk);
176}
177
178static void nr_idletimer_expiry(unsigned long param)
179{
180	struct sock *sk = (struct sock *)param;
181	struct nr_sock *nr = nr_sk(sk);
182
183	bh_lock_sock(sk);
184
185	nr_clear_queues(sk);
186
187	nr->n2count = 0;
188	nr_write_internal(sk, NR_DISCREQ);
189	nr->state = NR_STATE_2;
190
191	nr_start_t1timer(sk);
192	nr_stop_t2timer(sk);
193	nr_stop_t4timer(sk);
194
195	sk->sk_state     = TCP_CLOSE;
196	sk->sk_err       = 0;
197	sk->sk_shutdown |= SEND_SHUTDOWN;
198
199	if (!sock_flag(sk, SOCK_DEAD)) {
200		sk->sk_state_change(sk);
201		sock_set_flag(sk, SOCK_DEAD);
202	}
203	bh_unlock_sock(sk);
204}
205
206static void nr_t1timer_expiry(unsigned long param)
207{
208	struct sock *sk = (struct sock *)param;
209	struct nr_sock *nr = nr_sk(sk);
210
211	bh_lock_sock(sk);
212	switch (nr->state) {
213	case NR_STATE_1:
214		if (nr->n2count == nr->n2) {
215			nr_disconnect(sk, ETIMEDOUT);
216			bh_unlock_sock(sk);
217			return;
218		} else {
219			nr->n2count++;
220			nr_write_internal(sk, NR_CONNREQ);
221		}
222		break;
223
224	case NR_STATE_2:
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_DISCREQ);
232		}
233		break;
234
235	case NR_STATE_3:
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_requeue_frames(sk);
243		}
244		break;
245	}
246
247	nr_start_t1timer(sk);
248	bh_unlock_sock(sk);
249}
250