1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 * Copyright (C) 2002 Ralf Baechle DO1GRB (ralf@gnu.org)
6 */
7#include <linux/errno.h>
8#include <linux/types.h>
9#include <linux/socket.h>
10#include <linux/in.h>
11#include <linux/kernel.h>
12#include <linux/jiffies.h>
13#include <linux/timer.h>
14#include <linux/string.h>
15#include <linux/sockios.h>
16#include <linux/net.h>
17#include <net/ax25.h>
18#include <linux/inet.h>
19#include <linux/netdevice.h>
20#include <linux/skbuff.h>
21#include <net/sock.h>
22#include <net/tcp_states.h>
23#include <linux/fcntl.h>
24#include <linux/mm.h>
25#include <linux/interrupt.h>
26#include <net/rose.h>
27
28static void rose_heartbeat_expiry(struct timer_list *t);
29static void rose_timer_expiry(struct timer_list *);
30static void rose_idletimer_expiry(struct timer_list *);
31
32void rose_start_heartbeat(struct sock *sk)
33{
34	sk_stop_timer(sk, &sk->sk_timer);
35
36	sk->sk_timer.function = rose_heartbeat_expiry;
37	sk->sk_timer.expires  = jiffies + 5 * HZ;
38
39	sk_reset_timer(sk, &sk->sk_timer, sk->sk_timer.expires);
40}
41
42void rose_start_t1timer(struct sock *sk)
43{
44	struct rose_sock *rose = rose_sk(sk);
45
46	sk_stop_timer(sk, &rose->timer);
47
48	rose->timer.function = rose_timer_expiry;
49	rose->timer.expires  = jiffies + rose->t1;
50
51	sk_reset_timer(sk, &rose->timer, rose->timer.expires);
52}
53
54void rose_start_t2timer(struct sock *sk)
55{
56	struct rose_sock *rose = rose_sk(sk);
57
58	sk_stop_timer(sk, &rose->timer);
59
60	rose->timer.function = rose_timer_expiry;
61	rose->timer.expires  = jiffies + rose->t2;
62
63	sk_reset_timer(sk, &rose->timer, rose->timer.expires);
64}
65
66void rose_start_t3timer(struct sock *sk)
67{
68	struct rose_sock *rose = rose_sk(sk);
69
70	sk_stop_timer(sk, &rose->timer);
71
72	rose->timer.function = rose_timer_expiry;
73	rose->timer.expires  = jiffies + rose->t3;
74
75	sk_reset_timer(sk, &rose->timer, rose->timer.expires);
76}
77
78void rose_start_hbtimer(struct sock *sk)
79{
80	struct rose_sock *rose = rose_sk(sk);
81
82	sk_stop_timer(sk, &rose->timer);
83
84	rose->timer.function = rose_timer_expiry;
85	rose->timer.expires  = jiffies + rose->hb;
86
87	sk_reset_timer(sk, &rose->timer, rose->timer.expires);
88}
89
90void rose_start_idletimer(struct sock *sk)
91{
92	struct rose_sock *rose = rose_sk(sk);
93
94	sk_stop_timer(sk, &rose->idletimer);
95
96	if (rose->idle > 0) {
97		rose->idletimer.function = rose_idletimer_expiry;
98		rose->idletimer.expires  = jiffies + rose->idle;
99
100		sk_reset_timer(sk, &rose->idletimer, rose->idletimer.expires);
101	}
102}
103
104void rose_stop_heartbeat(struct sock *sk)
105{
106	sk_stop_timer(sk, &sk->sk_timer);
107}
108
109void rose_stop_timer(struct sock *sk)
110{
111	sk_stop_timer(sk, &rose_sk(sk)->timer);
112}
113
114void rose_stop_idletimer(struct sock *sk)
115{
116	sk_stop_timer(sk, &rose_sk(sk)->idletimer);
117}
118
119static void rose_heartbeat_expiry(struct timer_list *t)
120{
121	struct sock *sk = from_timer(sk, t, sk_timer);
122	struct rose_sock *rose = rose_sk(sk);
123
124	bh_lock_sock(sk);
125	switch (rose->state) {
126	case ROSE_STATE_0:
127		/* Magic here: If we listen() and a new link dies before it
128		   is accepted() it isn't 'dead' so doesn't get removed. */
129		if (sock_flag(sk, SOCK_DESTROY) ||
130		    (sk->sk_state == TCP_LISTEN && sock_flag(sk, SOCK_DEAD))) {
131			bh_unlock_sock(sk);
132			rose_destroy_socket(sk);
133			sock_put(sk);
134			return;
135		}
136		break;
137
138	case ROSE_STATE_3:
139		/*
140		 * Check for the state of the receive buffer.
141		 */
142		if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
143		    (rose->condition & ROSE_COND_OWN_RX_BUSY)) {
144			rose->condition &= ~ROSE_COND_OWN_RX_BUSY;
145			rose->condition &= ~ROSE_COND_ACK_PENDING;
146			rose->vl         = rose->vr;
147			rose_write_internal(sk, ROSE_RR);
148			rose_stop_timer(sk);	/* HB */
149			break;
150		}
151		break;
152	}
153
154	rose_start_heartbeat(sk);
155	bh_unlock_sock(sk);
156	sock_put(sk);
157}
158
159static void rose_timer_expiry(struct timer_list *t)
160{
161	struct rose_sock *rose = from_timer(rose, t, timer);
162	struct sock *sk = &rose->sock;
163
164	bh_lock_sock(sk);
165	switch (rose->state) {
166	case ROSE_STATE_1:	/* T1 */
167	case ROSE_STATE_4:	/* T2 */
168		rose_write_internal(sk, ROSE_CLEAR_REQUEST);
169		rose->state = ROSE_STATE_2;
170		rose_start_t3timer(sk);
171		break;
172
173	case ROSE_STATE_2:	/* T3 */
174		rose->neighbour->use--;
175		rose_disconnect(sk, ETIMEDOUT, -1, -1);
176		break;
177
178	case ROSE_STATE_3:	/* HB */
179		if (rose->condition & ROSE_COND_ACK_PENDING) {
180			rose->condition &= ~ROSE_COND_ACK_PENDING;
181			rose_enquiry_response(sk);
182		}
183		break;
184	}
185	bh_unlock_sock(sk);
186	sock_put(sk);
187}
188
189static void rose_idletimer_expiry(struct timer_list *t)
190{
191	struct rose_sock *rose = from_timer(rose, t, idletimer);
192	struct sock *sk = &rose->sock;
193
194	bh_lock_sock(sk);
195	rose_clear_queues(sk);
196
197	rose_write_internal(sk, ROSE_CLEAR_REQUEST);
198	rose_sk(sk)->state = ROSE_STATE_2;
199
200	rose_start_t3timer(sk);
201
202	sk->sk_state     = TCP_CLOSE;
203	sk->sk_err       = 0;
204	sk->sk_shutdown |= SEND_SHUTDOWN;
205
206	if (!sock_flag(sk, SOCK_DEAD)) {
207		sk->sk_state_change(sk);
208		sock_set_flag(sk, SOCK_DEAD);
209	}
210	bh_unlock_sock(sk);
211	sock_put(sk);
212}
213