1 /*
2 * AX.25 release 037
3 *
4 * This code REQUIRES 2.1.15 or higher/ NET3.038
5 *
6 * This module:
7 * This module is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * History
13 * AX.25 028a Jonathan(G4KLX) New state machine based on SDL diagrams.
14 * AX.25 028b Jonathan(G4KLX) Extracted AX25 control block from the
15 * sock structure.
16 * AX.25 029 Alan(GW4PTS) Switched to KA9Q constant names.
17 * AX.25 031 Joerg(DL1BKE) Added DAMA support
18 * AX.25 032 Joerg(DL1BKE) Fixed DAMA timeout bug
19 * AX.25 033 Jonathan(G4KLX) Modularisation functions.
20 * AX.25 035 Frederic(F1OAT) Support for pseudo-digipeating.
21 * AX.25 036 Jonathan(G4KLX) Split from ax25_timer.c.
22 * AX.25 037 Jonathan(G4KLX) New timer architecture.
23 */
24
25 #include <linux/errno.h>
26 #include <linux/types.h>
27 #include <linux/socket.h>
28 #include <linux/in.h>
29 #include <linux/kernel.h>
30 #include <linux/sched.h>
31 #include <linux/timer.h>
32 #include <linux/string.h>
33 #include <linux/sockios.h>
34 #include <linux/net.h>
35 #include <net/ax25.h>
36 #include <linux/inet.h>
37 #include <linux/netdevice.h>
38 #include <linux/skbuff.h>
39 #include <net/sock.h>
40 #include <asm/uaccess.h>
41 #include <asm/system.h>
42 #include <linux/fcntl.h>
43 #include <linux/mm.h>
44 #include <linux/interrupt.h>
45
46 void ax25_std_heartbeat_expiry(ax25_cb *ax25)
47 {
48 switch (ax25->state) {
49
50 case AX25_STATE_0:
51 /* Magic here: If we listen() and a new link dies before it
52 is accepted() it isn't 'dead' so doesn't get removed. */
53 if (ax25->sk == NULL || ax25->sk->destroy || (ax25->sk->state == TCP_LISTEN && ax25->sk->dead)) {
54 ax25_destroy_socket(ax25);
55 return;
56 }
57 break;
58
59 case AX25_STATE_3:
60 case AX25_STATE_4:
61 /*
62 * Check the state of the receive buffer.
63 */
64 if (ax25->sk != NULL) {
65 if (atomic_read(&ax25->sk->rmem_alloc) < (ax25->sk->rcvbuf / 2) &&
66 (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
67 ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
68 ax25->condition &= ~AX25_COND_ACK_PENDING;
69 ax25_send_control(ax25, AX25_RR, AX25_POLLOFF, AX25_RESPONSE);
70 break;
71 }
72 }
73 }
74
75 ax25_start_heartbeat(ax25);
76 }
77
78 void ax25_std_t2timer_expiry(ax25_cb *ax25)
79 {
80 if (ax25->condition & AX25_COND_ACK_PENDING) {
81 ax25->condition &= ~AX25_COND_ACK_PENDING;
82 ax25_std_timeout_response(ax25);
83 }
84 }
85
86 void ax25_std_t3timer_expiry(ax25_cb *ax25)
87 {
88 ax25->n2count = 0;
89 ax25_std_transmit_enquiry(ax25);
90 ax25->state = AX25_STATE_4;
91 }
92
93 void ax25_std_idletimer_expiry(ax25_cb *ax25)
94 {
95 ax25_clear_queues(ax25);
96
97 ax25->n2count = 0;
98 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
99 ax25->state = AX25_STATE_2;
100
101 ax25_calculate_t1(ax25);
102 ax25_start_t1timer(ax25);
103 ax25_stop_t2timer(ax25);
104 ax25_stop_t3timer(ax25);
105
106 if (ax25->sk != NULL) {
107 ax25->sk->state = TCP_CLOSE;
108 ax25->sk->err = 0;
109 ax25->sk->shutdown |= SEND_SHUTDOWN;
110 if (!ax25->sk->dead)
111 ax25->sk->state_change(ax25->sk);
112 ax25->sk->dead = 1;
113 }
114 }
115
116 void ax25_std_t1timer_expiry(ax25_cb *ax25)
117 {
118 switch (ax25->state) {
119 case AX25_STATE_1:
120 if (ax25->n2count == ax25->n2) {
121 if (ax25->modulus == AX25_MODULUS) {
122 ax25_disconnect(ax25, ETIMEDOUT);
123 return;
124 } else {
125 ax25->modulus = AX25_MODULUS;
126 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
127 ax25->n2count = 0;
128 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
129 }
130 } else {
131 ax25->n2count++;
132 if (ax25->modulus == AX25_MODULUS)
133 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
134 else
135 ax25_send_control(ax25, AX25_SABME, AX25_POLLON, AX25_COMMAND);
136 }
137 break;
138
139 case AX25_STATE_2:
140 if (ax25->n2count == ax25->n2) {
141 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
142 ax25_disconnect(ax25, ETIMEDOUT);
143 return;
144 } else {
145 ax25->n2count++;
146 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
147 }
148 break;
149
150 case AX25_STATE_3:
151 ax25->n2count = 1;
152 ax25_std_transmit_enquiry(ax25);
153 ax25->state = AX25_STATE_4;
154 break;
155
156 case AX25_STATE_4:
157 if (ax25->n2count == ax25->n2) {
158 ax25_send_control(ax25, AX25_DM, AX25_POLLON, AX25_RESPONSE);
159 ax25_disconnect(ax25, ETIMEDOUT);
160 return;
161 } else {
162 ax25->n2count++;
163 ax25_std_transmit_enquiry(ax25);
164 }
165 break;
166 }
167
168 ax25_calculate_t1(ax25);
169 ax25_start_t1timer(ax25);
170 }
171
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