1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * |
4 | * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk) |
5 | * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) |
6 | * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) |
7 | * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr) |
8 | */ |
9 | #include <linux/errno.h> |
10 | #include <linux/types.h> |
11 | #include <linux/socket.h> |
12 | #include <linux/in.h> |
13 | #include <linux/kernel.h> |
14 | #include <linux/timer.h> |
15 | #include <linux/string.h> |
16 | #include <linux/sockios.h> |
17 | #include <linux/net.h> |
18 | #include <net/ax25.h> |
19 | #include <linux/inet.h> |
20 | #include <linux/netdevice.h> |
21 | #include <linux/skbuff.h> |
22 | #include <net/sock.h> |
23 | #include <net/tcp_states.h> |
24 | #include <linux/uaccess.h> |
25 | #include <linux/fcntl.h> |
26 | #include <linux/mm.h> |
27 | #include <linux/interrupt.h> |
28 | |
29 | void ax25_std_heartbeat_expiry(ax25_cb *ax25) |
30 | { |
31 | struct sock *sk = ax25->sk; |
32 | |
33 | if (sk) |
34 | bh_lock_sock(sk); |
35 | |
36 | switch (ax25->state) { |
37 | case AX25_STATE_0: |
38 | case AX25_STATE_2: |
39 | /* Magic here: If we listen() and a new link dies before it |
40 | is accepted() it isn't 'dead' so doesn't get removed. */ |
41 | if (!sk || sock_flag(sk, flag: SOCK_DESTROY) || |
42 | (sk->sk_state == TCP_LISTEN && |
43 | sock_flag(sk, flag: SOCK_DEAD))) { |
44 | if (sk) { |
45 | sock_hold(sk); |
46 | ax25_destroy_socket(ax25); |
47 | bh_unlock_sock(sk); |
48 | /* Ungrab socket and destroy it */ |
49 | sock_put(sk); |
50 | } else |
51 | ax25_destroy_socket(ax25); |
52 | return; |
53 | } |
54 | break; |
55 | |
56 | case AX25_STATE_3: |
57 | case AX25_STATE_4: |
58 | /* |
59 | * Check the state of the receive buffer. |
60 | */ |
61 | if (sk != NULL) { |
62 | if (atomic_read(v: &sk->sk_rmem_alloc) < |
63 | (sk->sk_rcvbuf >> 1) && |
64 | (ax25->condition & AX25_COND_OWN_RX_BUSY)) { |
65 | ax25->condition &= ~AX25_COND_OWN_RX_BUSY; |
66 | ax25->condition &= ~AX25_COND_ACK_PENDING; |
67 | ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE); |
68 | break; |
69 | } |
70 | } |
71 | } |
72 | |
73 | if (sk) |
74 | bh_unlock_sock(sk); |
75 | |
76 | ax25_start_heartbeat(ax25); |
77 | } |
78 | |
79 | void ax25_std_t2timer_expiry(ax25_cb *ax25) |
80 | { |
81 | if (ax25->condition & AX25_COND_ACK_PENDING) { |
82 | ax25->condition &= ~AX25_COND_ACK_PENDING; |
83 | ax25_std_timeout_response(ax25); |
84 | } |
85 | } |
86 | |
87 | void ax25_std_t3timer_expiry(ax25_cb *ax25) |
88 | { |
89 | ax25->n2count = 0; |
90 | ax25_std_transmit_enquiry(ax25); |
91 | ax25->state = AX25_STATE_4; |
92 | } |
93 | |
94 | void ax25_std_idletimer_expiry(ax25_cb *ax25) |
95 | { |
96 | ax25_clear_queues(ax25); |
97 | |
98 | ax25->n2count = 0; |
99 | ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); |
100 | ax25->state = AX25_STATE_2; |
101 | |
102 | ax25_calculate_t1(ax25); |
103 | ax25_start_t1timer(ax25); |
104 | ax25_stop_t2timer(ax25); |
105 | ax25_stop_t3timer(ax25); |
106 | |
107 | if (ax25->sk != NULL) { |
108 | bh_lock_sock(ax25->sk); |
109 | ax25->sk->sk_state = TCP_CLOSE; |
110 | ax25->sk->sk_err = 0; |
111 | ax25->sk->sk_shutdown |= SEND_SHUTDOWN; |
112 | if (!sock_flag(sk: ax25->sk, flag: SOCK_DEAD)) { |
113 | ax25->sk->sk_state_change(ax25->sk); |
114 | sock_set_flag(sk: ax25->sk, flag: SOCK_DEAD); |
115 | } |
116 | bh_unlock_sock(ax25->sk); |
117 | } |
118 | } |
119 | |
120 | void ax25_std_t1timer_expiry(ax25_cb *ax25) |
121 | { |
122 | switch (ax25->state) { |
123 | case AX25_STATE_1: |
124 | if (ax25->n2count == ax25->n2) { |
125 | if (ax25->modulus == AX25_MODULUS) { |
126 | ax25_disconnect(ax25, ETIMEDOUT); |
127 | return; |
128 | } else { |
129 | ax25->modulus = AX25_MODULUS; |
130 | ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW]; |
131 | ax25->n2count = 0; |
132 | ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); |
133 | } |
134 | } else { |
135 | ax25->n2count++; |
136 | if (ax25->modulus == AX25_MODULUS) |
137 | ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND); |
138 | else |
139 | ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND); |
140 | } |
141 | break; |
142 | |
143 | case AX25_STATE_2: |
144 | if (ax25->n2count == ax25->n2) { |
145 | ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND); |
146 | if (!sock_flag(sk: ax25->sk, flag: SOCK_DESTROY)) |
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 | |