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 
29 static void nr_heartbeat_expiry(struct timer_list *);
30 static void nr_t1timer_expiry(struct timer_list *);
31 static void nr_t2timer_expiry(struct timer_list *);
32 static void nr_t4timer_expiry(struct timer_list *);
33 static void nr_idletimer_expiry(struct timer_list *);
34 
nr_init_timers(struct sock * sk)35 void 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 
nr_start_t1timer(struct sock * sk)48 void 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 
nr_start_t2timer(struct sock * sk)55 void 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 
nr_start_t4timer(struct sock * sk)62 void 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 
nr_start_idletimer(struct sock * sk)69 void 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 
nr_start_heartbeat(struct sock * sk)77 void nr_start_heartbeat(struct sock *sk)
78 {
79 	sk_reset_timer(sk, &sk->sk_timer, jiffies + 5 * HZ);
80 }
81 
nr_stop_t1timer(struct sock * sk)82 void nr_stop_t1timer(struct sock *sk)
83 {
84 	sk_stop_timer(sk, &nr_sk(sk)->t1timer);
85 }
86 
nr_stop_t2timer(struct sock * sk)87 void nr_stop_t2timer(struct sock *sk)
88 {
89 	sk_stop_timer(sk, &nr_sk(sk)->t2timer);
90 }
91 
nr_stop_t4timer(struct sock * sk)92 void nr_stop_t4timer(struct sock *sk)
93 {
94 	sk_stop_timer(sk, &nr_sk(sk)->t4timer);
95 }
96 
nr_stop_idletimer(struct sock * sk)97 void nr_stop_idletimer(struct sock *sk)
98 {
99 	sk_stop_timer(sk, &nr_sk(sk)->idletimer);
100 }
101 
nr_stop_heartbeat(struct sock * sk)102 void nr_stop_heartbeat(struct sock *sk)
103 {
104 	sk_stop_timer(sk, &sk->sk_timer);
105 }
106 
nr_t1timer_running(struct sock * sk)107 int nr_t1timer_running(struct sock *sk)
108 {
109 	return timer_pending(&nr_sk(sk)->t1timer);
110 }
111 
nr_heartbeat_expiry(struct timer_list * t)112 static 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 			bh_unlock_sock(sk);
125 			nr_destroy_socket(sk);
126 			goto out;
127 		}
128 		break;
129 
130 	case NR_STATE_3:
131 		/*
132 		 * Check for the state of the receive buffer.
133 		 */
134 		if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
135 		    (nr->condition & NR_COND_OWN_RX_BUSY)) {
136 			nr->condition &= ~NR_COND_OWN_RX_BUSY;
137 			nr->condition &= ~NR_COND_ACK_PENDING;
138 			nr->vl         = nr->vr;
139 			nr_write_internal(sk, NR_INFOACK);
140 			break;
141 		}
142 		break;
143 	}
144 
145 	nr_start_heartbeat(sk);
146 	bh_unlock_sock(sk);
147 out:
148 	sock_put(sk);
149 }
150 
nr_t2timer_expiry(struct timer_list * t)151 static void nr_t2timer_expiry(struct timer_list *t)
152 {
153 	struct nr_sock *nr = from_timer(nr, t, t2timer);
154 	struct sock *sk = &nr->sock;
155 
156 	bh_lock_sock(sk);
157 	if (nr->condition & NR_COND_ACK_PENDING) {
158 		nr->condition &= ~NR_COND_ACK_PENDING;
159 		nr_enquiry_response(sk);
160 	}
161 	bh_unlock_sock(sk);
162 	sock_put(sk);
163 }
164 
nr_t4timer_expiry(struct timer_list * t)165 static void nr_t4timer_expiry(struct timer_list *t)
166 {
167 	struct nr_sock *nr = from_timer(nr, t, t4timer);
168 	struct sock *sk = &nr->sock;
169 
170 	bh_lock_sock(sk);
171 	nr_sk(sk)->condition &= ~NR_COND_PEER_RX_BUSY;
172 	bh_unlock_sock(sk);
173 	sock_put(sk);
174 }
175 
nr_idletimer_expiry(struct timer_list * t)176 static void nr_idletimer_expiry(struct timer_list *t)
177 {
178 	struct nr_sock *nr = from_timer(nr, t, idletimer);
179 	struct sock *sk = &nr->sock;
180 
181 	bh_lock_sock(sk);
182 
183 	nr_clear_queues(sk);
184 
185 	nr->n2count = 0;
186 	nr_write_internal(sk, NR_DISCREQ);
187 	nr->state = NR_STATE_2;
188 
189 	nr_start_t1timer(sk);
190 	nr_stop_t2timer(sk);
191 	nr_stop_t4timer(sk);
192 
193 	sk->sk_state     = TCP_CLOSE;
194 	sk->sk_err       = 0;
195 	sk->sk_shutdown |= SEND_SHUTDOWN;
196 
197 	if (!sock_flag(sk, SOCK_DEAD)) {
198 		sk->sk_state_change(sk);
199 		sock_set_flag(sk, SOCK_DEAD);
200 	}
201 	bh_unlock_sock(sk);
202 	sock_put(sk);
203 }
204 
nr_t1timer_expiry(struct timer_list * t)205 static void nr_t1timer_expiry(struct timer_list *t)
206 {
207 	struct nr_sock *nr = from_timer(nr, t, t1timer);
208 	struct sock *sk = &nr->sock;
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 			goto out;
216 		} else {
217 			nr->n2count++;
218 			nr_write_internal(sk, NR_CONNREQ);
219 		}
220 		break;
221 
222 	case NR_STATE_2:
223 		if (nr->n2count == nr->n2) {
224 			nr_disconnect(sk, ETIMEDOUT);
225 			goto out;
226 		} else {
227 			nr->n2count++;
228 			nr_write_internal(sk, NR_DISCREQ);
229 		}
230 		break;
231 
232 	case NR_STATE_3:
233 		if (nr->n2count == nr->n2) {
234 			nr_disconnect(sk, ETIMEDOUT);
235 			goto out;
236 		} else {
237 			nr->n2count++;
238 			nr_requeue_frames(sk);
239 		}
240 		break;
241 	}
242 
243 	nr_start_t1timer(sk);
244 out:
245 	bh_unlock_sock(sk);
246 	sock_put(sk);
247 }
248