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-rw-r--r--net/ax25/ax25_ds_in.c305
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diff --git a/net/ax25/ax25_ds_in.c b/net/ax25/ax25_ds_in.c
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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) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
9 */
10#include <linux/errno.h>
11#include <linux/types.h>
12#include <linux/socket.h>
13#include <linux/in.h>
14#include <linux/kernel.h>
15#include <linux/sched.h>
16#include <linux/timer.h>
17#include <linux/string.h>
18#include <linux/sockios.h>
19#include <linux/net.h>
20#include <net/ax25.h>
21#include <linux/inet.h>
22#include <linux/netdevice.h>
23#include <linux/skbuff.h>
24#include <net/sock.h>
25#include <net/ip.h> /* For ip_rcv */
26#include <net/tcp.h>
27#include <asm/uaccess.h>
28#include <asm/system.h>
29#include <linux/fcntl.h>
30#include <linux/mm.h>
31#include <linux/interrupt.h>
32
33/*
34 * State machine for state 1, Awaiting Connection State.
35 * The handling of the timer(s) is in file ax25_ds_timer.c.
36 * Handling of state 0 and connection release is in ax25.c.
37 */
38static int ax25_ds_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
39{
40 switch (frametype) {
41 case AX25_SABM:
42 ax25->modulus = AX25_MODULUS;
43 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
44 ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
45 break;
46
47 case AX25_SABME:
48 ax25->modulus = AX25_EMODULUS;
49 ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
50 ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
51 break;
52
53 case AX25_DISC:
54 ax25_send_control(ax25, AX25_DM, pf, AX25_RESPONSE);
55 break;
56
57 case AX25_UA:
58 ax25_calculate_rtt(ax25);
59 ax25_stop_t1timer(ax25);
60 ax25_start_t3timer(ax25);
61 ax25_start_idletimer(ax25);
62 ax25->vs = 0;
63 ax25->va = 0;
64 ax25->vr = 0;
65 ax25->state = AX25_STATE_3;
66 ax25->n2count = 0;
67 if (ax25->sk != NULL) {
68 bh_lock_sock(ax25->sk);
69 ax25->sk->sk_state = TCP_ESTABLISHED;
70 /*
71 * For WAIT_SABM connections we will produce an accept
72 * ready socket here
73 */
74 if (!sock_flag(ax25->sk, SOCK_DEAD))
75 ax25->sk->sk_state_change(ax25->sk);
76 bh_unlock_sock(ax25->sk);
77 }
78 ax25_dama_on(ax25);
79
80 /* according to DK4EG´s spec we are required to
81 * send a RR RESPONSE FINAL NR=0.
82 */
83
84 ax25_std_enquiry_response(ax25);
85 break;
86
87 case AX25_DM:
88 if (pf)
89 ax25_disconnect(ax25, ECONNREFUSED);
90 break;
91
92 default:
93 if (pf)
94 ax25_send_control(ax25, AX25_SABM, AX25_POLLON, AX25_COMMAND);
95 break;
96 }
97
98 return 0;
99}
100
101/*
102 * State machine for state 2, Awaiting Release State.
103 * The handling of the timer(s) is in file ax25_ds_timer.c
104 * Handling of state 0 and connection release is in ax25.c.
105 */
106static int ax25_ds_state2_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int pf, int type)
107{
108 switch (frametype) {
109 case AX25_SABM:
110 case AX25_SABME:
111 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
112 ax25_dama_off(ax25);
113 break;
114
115 case AX25_DISC:
116 ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
117 ax25_dama_off(ax25);
118 ax25_disconnect(ax25, 0);
119 break;
120
121 case AX25_DM:
122 case AX25_UA:
123 if (pf) {
124 ax25_dama_off(ax25);
125 ax25_disconnect(ax25, 0);
126 }
127 break;
128
129 case AX25_I:
130 case AX25_REJ:
131 case AX25_RNR:
132 case AX25_RR:
133 if (pf) {
134 ax25_send_control(ax25, AX25_DISC, AX25_POLLON, AX25_COMMAND);
135 ax25_dama_off(ax25);
136 }
137 break;
138
139 default:
140 break;
141 }
142
143 return 0;
144}
145
146/*
147 * State machine for state 3, Connected State.
148 * The handling of the timer(s) is in file ax25_timer.c
149 * Handling of state 0 and connection release is in ax25.c.
150 */
151static int ax25_ds_state3_machine(ax25_cb *ax25, struct sk_buff *skb, int frametype, int ns, int nr, int pf, int type)
152{
153 int queued = 0;
154
155 switch (frametype) {
156 case AX25_SABM:
157 case AX25_SABME:
158 if (frametype == AX25_SABM) {
159 ax25->modulus = AX25_MODULUS;
160 ax25->window = ax25->ax25_dev->values[AX25_VALUES_WINDOW];
161 } else {
162 ax25->modulus = AX25_EMODULUS;
163 ax25->window = ax25->ax25_dev->values[AX25_VALUES_EWINDOW];
164 }
165 ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
166 ax25_stop_t1timer(ax25);
167 ax25_start_t3timer(ax25);
168 ax25_start_idletimer(ax25);
169 ax25->condition = 0x00;
170 ax25->vs = 0;
171 ax25->va = 0;
172 ax25->vr = 0;
173 ax25_requeue_frames(ax25);
174 ax25_dama_on(ax25);
175 break;
176
177 case AX25_DISC:
178 ax25_send_control(ax25, AX25_UA, pf, AX25_RESPONSE);
179 ax25_dama_off(ax25);
180 ax25_disconnect(ax25, 0);
181 break;
182
183 case AX25_DM:
184 ax25_dama_off(ax25);
185 ax25_disconnect(ax25, ECONNRESET);
186 break;
187
188 case AX25_RR:
189 case AX25_RNR:
190 if (frametype == AX25_RR)
191 ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
192 else
193 ax25->condition |= AX25_COND_PEER_RX_BUSY;
194
195 if (ax25_validate_nr(ax25, nr)) {
196 if (ax25_check_iframes_acked(ax25, nr))
197 ax25->n2count=0;
198 if (type == AX25_COMMAND && pf)
199 ax25_ds_enquiry_response(ax25);
200 } else {
201 ax25_ds_nr_error_recovery(ax25);
202 ax25->state = AX25_STATE_1;
203 }
204 break;
205
206 case AX25_REJ:
207 ax25->condition &= ~AX25_COND_PEER_RX_BUSY;
208
209 if (ax25_validate_nr(ax25, nr)) {
210 if (ax25->va != nr)
211 ax25->n2count=0;
212
213 ax25_frames_acked(ax25, nr);
214 ax25_calculate_rtt(ax25);
215 ax25_stop_t1timer(ax25);
216 ax25_start_t3timer(ax25);
217 ax25_requeue_frames(ax25);
218
219 if (type == AX25_COMMAND && pf)
220 ax25_ds_enquiry_response(ax25);
221 } else {
222 ax25_ds_nr_error_recovery(ax25);
223 ax25->state = AX25_STATE_1;
224 }
225 break;
226
227 case AX25_I:
228 if (!ax25_validate_nr(ax25, nr)) {
229 ax25_ds_nr_error_recovery(ax25);
230 ax25->state = AX25_STATE_1;
231 break;
232 }
233 if (ax25->condition & AX25_COND_PEER_RX_BUSY) {
234 ax25_frames_acked(ax25, nr);
235 ax25->n2count = 0;
236 } else {
237 if (ax25_check_iframes_acked(ax25, nr))
238 ax25->n2count = 0;
239 }
240 if (ax25->condition & AX25_COND_OWN_RX_BUSY) {
241 if (pf) ax25_ds_enquiry_response(ax25);
242 break;
243 }
244 if (ns == ax25->vr) {
245 ax25->vr = (ax25->vr + 1) % ax25->modulus;
246 queued = ax25_rx_iframe(ax25, skb);
247 if (ax25->condition & AX25_COND_OWN_RX_BUSY)
248 ax25->vr = ns; /* ax25->vr - 1 */
249 ax25->condition &= ~AX25_COND_REJECT;
250 if (pf) {
251 ax25_ds_enquiry_response(ax25);
252 } else {
253 if (!(ax25->condition & AX25_COND_ACK_PENDING)) {
254 ax25->condition |= AX25_COND_ACK_PENDING;
255 ax25_start_t2timer(ax25);
256 }
257 }
258 } else {
259 if (ax25->condition & AX25_COND_REJECT) {
260 if (pf) ax25_ds_enquiry_response(ax25);
261 } else {
262 ax25->condition |= AX25_COND_REJECT;
263 ax25_ds_enquiry_response(ax25);
264 ax25->condition &= ~AX25_COND_ACK_PENDING;
265 }
266 }
267 break;
268
269 case AX25_FRMR:
270 case AX25_ILLEGAL:
271 ax25_ds_establish_data_link(ax25);
272 ax25->state = AX25_STATE_1;
273 break;
274
275 default:
276 break;
277 }
278
279 return queued;
280}
281
282/*
283 * Higher level upcall for a LAPB frame
284 */
285int ax25_ds_frame_in(ax25_cb *ax25, struct sk_buff *skb, int type)
286{
287 int queued = 0, frametype, ns, nr, pf;
288
289 frametype = ax25_decode(ax25, skb, &ns, &nr, &pf);
290
291 switch (ax25->state) {
292 case AX25_STATE_1:
293 queued = ax25_ds_state1_machine(ax25, skb, frametype, pf, type);
294 break;
295 case AX25_STATE_2:
296 queued = ax25_ds_state2_machine(ax25, skb, frametype, pf, type);
297 break;
298 case AX25_STATE_3:
299 queued = ax25_ds_state3_machine(ax25, skb, frametype, ns, nr, pf, type);
300 break;
301 }
302
303 return queued;
304}
305
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