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