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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
8 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
9 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
10 * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
11 */
12 #include <linux/errno.h>
13 #include <linux/types.h>
14 #include <linux/socket.h>
15 #include <linux/in.h>
16 #include <linux/kernel.h>
17 #include <linux/timer.h>
18 #include <linux/string.h>
19 #include <linux/sockios.h>
20 #include <linux/net.h>
21 #include <net/ax25.h>
22 #include <linux/inet.h>
23 #include <linux/netdevice.h>
24 #include <linux/skbuff.h>
25 #include <net/sock.h>
26 #include <net/tcp_states.h>
27 #include <asm/uaccess.h>
28 #include <linux/fcntl.h>
29 #include <linux/mm.h>
30 #include <linux/interrupt.h>
31
ax25_std_heartbeat_expiry(ax25_cb * ax25)32 void ax25_std_heartbeat_expiry(ax25_cb *ax25)
33 {
34 struct sock *sk = ax25->sk;
35
36 if (sk)
37 bh_lock_sock(sk);
38
39 switch (ax25->state) {
40 case AX25_STATE_0:
41 /* Magic here: If we listen() and a new link dies before it
42 is accepted() it isn't 'dead' so doesn't get removed. */
43 if (!sk || sock_flag(sk, SOCK_DESTROY) ||
44 (sk->sk_state == TCP_LISTEN &&
45 sock_flag(sk, SOCK_DEAD))) {
46 if (sk) {
47 sock_hold(sk);
48 ax25_destroy_socket(ax25);
49 bh_unlock_sock(sk);
50 sock_put(sk);
51 } else
52 ax25_destroy_socket(ax25);
53 return;
54 }
55 break;
56
57 case AX25_STATE_3:
58 case AX25_STATE_4:
59 /*
60 * Check the state of the receive buffer.
61 */
62 if (sk != NULL) {
63 if (atomic_read(&sk->sk_rmem_alloc) <
64 (sk->sk_rcvbuf >> 1) &&
65 (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
66 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
67 ax25->condition &= ~AX25_COND_ACK_PENDING;
68 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
69 break;
70 }
71 }
72 }
73
74 if (sk)
75 bh_unlock_sock(sk);
76
77 ax25_start_heartbeat(ax25);
78 }
79
ax25_std_t2timer_expiry(ax25_cb * ax25)80 void ax25_std_t2timer_expiry(ax25_cb *ax25)
81 {
82 if (ax25->condition & AX25_COND_ACK_PENDING) {
83 ax25->condition &= ~AX25_COND_ACK_PENDING;
84 ax25_std_timeout_response(ax25);
85 }
86 }
87
ax25_std_t3timer_expiry(ax25_cb * ax25)88 void ax25_std_t3timer_expiry(ax25_cb *ax25)
89 {
90 ax25->n2count = 0;
91 ax25_std_transmit_enquiry(ax25);
92 ax25->state = AX25_STATE_4;
93 }
94
ax25_std_idletimer_expiry(ax25_cb * ax25)95 void ax25_std_idletimer_expiry(ax25_cb *ax25)
96 {
97 ax25_clear_queues(ax25);
98
99 ax25->n2count = 0;
100 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
101 ax25->state = AX25_STATE_2;
102
103 ax25_calculate_t1(ax25);
104 ax25_start_t1timer(ax25);
105 ax25_stop_t2timer(ax25);
106 ax25_stop_t3timer(ax25);
107
108 if (ax25->sk != NULL) {
109 bh_lock_sock(ax25->sk);
110 ax25->sk->sk_state = TCP_CLOSE;
111 ax25->sk->sk_err = 0;
112 ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
113 if (!sock_flag(ax25->sk, SOCK_DEAD)) {
114 ax25->sk->sk_state_change(ax25->sk);
115 sock_set_flag(ax25->sk, SOCK_DEAD);
116 }
117 bh_unlock_sock(ax25->sk);
118 }
119 }
120
ax25_std_t1timer_expiry(ax25_cb * ax25)121 void ax25_std_t1timer_expiry(ax25_cb *ax25)
122 {
123 switch (ax25->state) {
124 case AX25_STATE_1:
125 if (ax25->n2count == ax25->n2) {
126 if (ax25->modulus == AX25_MODULUS) {
127 ax25_disconnect(ax25, ETIMEDOUT);
128 return;
129 } else {
130 ax25->modulus = AX25_MODULUS;
131 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
132 ax25->n2count = 0;
133 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
134 }
135 } else {
136 ax25->n2count++;
137 if (ax25->modulus == AX25_MODULUS)
138 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
139 else
140 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
141 }
142 break;
143
144 case AX25_STATE_2:
145 if (ax25->n2count == ax25->n2) {
146 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
147 ax25_disconnect(ax25, ETIMEDOUT);
148 return;
149 } else {
150 ax25->n2count++;
151 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
152 }
153 break;
154
155 case AX25_STATE_3:
156 ax25->n2count = 1;
157 ax25_std_transmit_enquiry(ax25);
158 ax25->state = AX25_STATE_4;
159 break;
160
161 case AX25_STATE_4:
162 if (ax25->n2count == ax25->n2) {
163 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
164 ax25_disconnect(ax25, ETIMEDOUT);
165 return;
166 } else {
167 ax25->n2count++;
168 ax25_std_transmit_enquiry(ax25);
169 }
170 break;
171 }
172
173 ax25_calculate_t1(ax25);
174 ax25_start_t1timer(ax25);
175 }
176