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