xref: /kernel/linux/linux-6.6/net/netrom/nr_timer.c (revision 62306a36) 
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/uaccess.h>
24#include <linux/fcntl.h>
25#include <linux/mm.h>
26#include <linux/interrupt.h>
27#include <net/netrom.h>
28
29static void nr_heartbeat_expiry(struct timer_list *);
30static void nr_t1timer_expiry(struct timer_list *);
31static void nr_t2timer_expiry(struct timer_list *);
32static void nr_t4timer_expiry(struct timer_list *);
33static void nr_idletimer_expiry(struct timer_list *);
34
35void nr_init_timers(struct sock *sk)
36{
37	struct nr_sock *nr = nr_sk(sk);
38
39	timer_setup(&nr->t1timer, nr_t1timer_expiry, 0);
40	timer_setup(&nr->t2timer, nr_t2timer_expiry, 0);
41	timer_setup(&nr->t4timer, nr_t4timer_expiry, 0);
42	timer_setup(&nr->idletimer, nr_idletimer_expiry, 0);
43
44	/* initialized by sock_init_data */
45	sk->sk_timer.function = nr_heartbeat_expiry;
46}
47
48void nr_start_t1timer(struct sock *sk)
49{
50	struct nr_sock *nr = nr_sk(sk);
51
52	sk_reset_timer(sk, &nr->t1timer, jiffies + nr->t1);
53}
54
55void nr_start_t2timer(struct sock *sk)
56{
57	struct nr_sock *nr = nr_sk(sk);
58
59	sk_reset_timer(sk, &nr->t2timer, jiffies + nr->t2);
60}
61
62void nr_start_t4timer(struct sock *sk)
63{
64	struct nr_sock *nr = nr_sk(sk);
65
66	sk_reset_timer(sk, &nr->t4timer, jiffies + nr->t4);
67}
68
69void nr_start_idletimer(struct sock *sk)
70{
71	struct nr_sock *nr = nr_sk(sk);
72
73	if (nr->idle > 0)
74		sk_reset_timer(sk, &nr->idletimer, jiffies + nr->idle);
75}
76
77void nr_start_heartbeat(struct sock *sk)
78{
79	sk_reset_timer(sk, &sk->sk_timer, jiffies + 5 * HZ);
80}
81
82void nr_stop_t1timer(struct sock *sk)
83{
84	sk_stop_timer(sk, &nr_sk(sk)->t1timer);
85}
86
87void nr_stop_t2timer(struct sock *sk)
88{
89	sk_stop_timer(sk, &nr_sk(sk)->t2timer);
90}
91
92void nr_stop_t4timer(struct sock *sk)
93{
94	sk_stop_timer(sk, &nr_sk(sk)->t4timer);
95}
96
97void nr_stop_idletimer(struct sock *sk)
98{
99	sk_stop_timer(sk, &nr_sk(sk)->idletimer);
100}
101
102void nr_stop_heartbeat(struct sock *sk)
103{
104	sk_stop_timer(sk, &sk->sk_timer);
105}
106
107int nr_t1timer_running(struct sock *sk)
108{
109	return timer_pending(&nr_sk(sk)->t1timer);
110}
111
112static void nr_heartbeat_expiry(struct timer_list *t)
113{
114	struct sock *sk = from_timer(sk, t, sk_timer);
115	struct nr_sock *nr = nr_sk(sk);
116
117	bh_lock_sock(sk);
118	switch (nr->state) {
119	case NR_STATE_0:
120		/* Magic here: If we listen() and a new link dies before it
121		   is accepted() it isn't 'dead' so doesn't get removed. */
122		if (sock_flag(sk, SOCK_DESTROY) ||
123		    (sk->sk_state == TCP_LISTEN && sock_flag(sk, SOCK_DEAD))) {
124			sock_hold(sk);
125			bh_unlock_sock(sk);
126			nr_destroy_socket(sk);
127			goto out;
128		}
129		break;
130
131	case NR_STATE_3:
132		/*
133		 * Check for the state of the receive buffer.
134		 */
135		if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
136		    (nr->condition & NR_COND_OWN_RX_BUSY)) {
137			nr->condition &= ~NR_COND_OWN_RX_BUSY;
138			nr->condition &= ~NR_COND_ACK_PENDING;
139			nr->vl         = nr->vr;
140			nr_write_internal(sk, NR_INFOACK);
141			break;
142		}
143		break;
144	}
145
146	nr_start_heartbeat(sk);
147	bh_unlock_sock(sk);
148out:
149	sock_put(sk);
150}
151
152static void nr_t2timer_expiry(struct timer_list *t)
153{
154	struct nr_sock *nr = from_timer(nr, t, t2timer);
155	struct sock *sk = &nr->sock;
156
157	bh_lock_sock(sk);
158	if (nr->condition & NR_COND_ACK_PENDING) {
159		nr->condition &= ~NR_COND_ACK_PENDING;
160		nr_enquiry_response(sk);
161	}
162	bh_unlock_sock(sk);
163	sock_put(sk);
164}
165
166static void nr_t4timer_expiry(struct timer_list *t)
167{
168	struct nr_sock *nr = from_timer(nr, t, t4timer);
169	struct sock *sk = &nr->sock;
170
171	bh_lock_sock(sk);
172	nr_sk(sk)->condition &= ~NR_COND_PEER_RX_BUSY;
173	bh_unlock_sock(sk);
174	sock_put(sk);
175}
176
177static void nr_idletimer_expiry(struct timer_list *t)
178{
179	struct nr_sock *nr = from_timer(nr, t, idletimer);
180	struct sock *sk = &nr->sock;
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	sock_put(sk);
204}
205
206static void nr_t1timer_expiry(struct timer_list *t)
207{
208	struct nr_sock *nr = from_timer(nr, t, t1timer);
209	struct sock *sk = &nr->sock;
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			goto out;
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			goto out;
227		} else {
228			nr->n2count++;
229			nr_write_internal(sk, NR_DISCREQ);
230		}
231		break;
232
233	case NR_STATE_3:
234		if (nr->n2count == nr->n2) {
235			nr_disconnect(sk, ETIMEDOUT);
236			goto out;
237		} else {
238			nr->n2count++;
239			nr_requeue_frames(sk);
240		}
241		break;
242	}
243
244	nr_start_t1timer(sk);
245out:
246	bh_unlock_sock(sk);
247	sock_put(sk);
248}
249