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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - net/ax25/ax25_std_in.c
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.
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) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
12 * Most of this code is based on the SDL diagrams published in the 7th ARRL
13 * Computer Networking Conference papers. The diagrams have mistakes in them,
14 * but are mostly correct. Before you modify the code could you read the SDL
15 * diagrams as the code is not obvious and probably very easy to break.
17 #include <linux/errno.h>
18 #include <linux/types.h>
19 #include <linux/socket.h>
21 #include <linux/kernel.h>
22 #include <linux/timer.h>
23 #include <linux/string.h>
24 #include <linux/sockios.h>
25 #include <linux/net.h>
27 #include <linux/inet.h>
28 #include <linux/netdevice.h>
29 #include <linux/skbuff.h>
31 #include <net/tcp_states.h>
32 #include <asm/uaccess.h>
33 #include <linux/fcntl.h>
35 #include <linux/interrupt.h>
38 * State machine for state 1, Awaiting Connection State.
39 * The handling of the timer(s) is in file ax25_std_timer.c.
40 * Handling of state 0 and connection release is in ax25.c.
42 static int ax25_std_state1_machine(ax25_cb
*ax25
, struct sk_buff
*skb
, int frametype
, int pf
, int type
)
46 ax25
->modulus
= AX25_MODULUS
;
47 ax25
->window
= ax25
->ax25_dev
->values
[AX25_VALUES_WINDOW
];
48 ax25_send_control(ax25
, AX25_UA
, pf
, AX25_RESPONSE
);
52 ax25
->modulus
= AX25_EMODULUS
;
53 ax25
->window
= ax25
->ax25_dev
->values
[AX25_VALUES_EWINDOW
];
54 ax25_send_control(ax25
, AX25_UA
, pf
, AX25_RESPONSE
);
58 ax25_send_control(ax25
, AX25_DM
, pf
, AX25_RESPONSE
);
63 ax25_calculate_rtt(ax25
);
64 ax25_stop_t1timer(ax25
);
65 ax25_start_t3timer(ax25
);
66 ax25_start_idletimer(ax25
);
70 ax25
->state
= AX25_STATE_3
;
72 if (ax25
->sk
!= NULL
) {
73 bh_lock_sock(ax25
->sk
);
74 ax25
->sk
->sk_state
= TCP_ESTABLISHED
;
75 /* For WAIT_SABM connections we will produce an accept ready socket here */
76 if (!sock_flag(ax25
->sk
, SOCK_DEAD
))
77 ax25
->sk
->sk_state_change(ax25
->sk
);
78 bh_unlock_sock(ax25
->sk
);
85 if (ax25
->modulus
== AX25_MODULUS
) {
86 ax25_disconnect(ax25
, ECONNREFUSED
);
88 ax25
->modulus
= AX25_MODULUS
;
89 ax25
->window
= ax25
->ax25_dev
->values
[AX25_VALUES_WINDOW
];
102 * State machine for state 2, Awaiting Release State.
103 * The handling of the timer(s) is in file ax25_std_timer.c
104 * Handling of state 0 and connection release is in ax25.c.
106 static int ax25_std_state2_machine(ax25_cb
*ax25
, struct sk_buff
*skb
, int frametype
, int pf
, int type
)
111 ax25_send_control(ax25
, AX25_DM
, pf
, AX25_RESPONSE
);
115 ax25_send_control(ax25
, AX25_UA
, pf
, AX25_RESPONSE
);
116 ax25_disconnect(ax25
, 0);
122 ax25_disconnect(ax25
, 0);
129 if (pf
) ax25_send_control(ax25
, AX25_DM
, AX25_POLLON
, AX25_RESPONSE
);
140 * State machine for state 3, Connected State.
141 * The handling of the timer(s) is in file ax25_std_timer.c
142 * Handling of state 0 and connection release is in ax25.c.
144 static int ax25_std_state3_machine(ax25_cb
*ax25
, struct sk_buff
*skb
, int frametype
, int ns
, int nr
, int pf
, int type
)
151 if (frametype
== AX25_SABM
) {
152 ax25
->modulus
= AX25_MODULUS
;
153 ax25
->window
= ax25
->ax25_dev
->values
[AX25_VALUES_WINDOW
];
155 ax25
->modulus
= AX25_EMODULUS
;
156 ax25
->window
= ax25
->ax25_dev
->values
[AX25_VALUES_EWINDOW
];
158 ax25_send_control(ax25
, AX25_UA
, pf
, AX25_RESPONSE
);
159 ax25_stop_t1timer(ax25
);
160 ax25_stop_t2timer(ax25
);
161 ax25_start_t3timer(ax25
);
162 ax25_start_idletimer(ax25
);
163 ax25
->condition
= 0x00;
167 ax25_requeue_frames(ax25
);
171 ax25_send_control(ax25
, AX25_UA
, pf
, AX25_RESPONSE
);
172 ax25_disconnect(ax25
, 0);
176 ax25_disconnect(ax25
, ECONNRESET
);
181 if (frametype
== AX25_RR
)
182 ax25
->condition
&= ~AX25_COND_PEER_RX_BUSY
;
184 ax25
->condition
|= AX25_COND_PEER_RX_BUSY
;
185 if (type
== AX25_COMMAND
&& pf
)
186 ax25_std_enquiry_response(ax25
);
187 if (ax25_validate_nr(ax25
, nr
)) {
188 ax25_check_iframes_acked(ax25
, nr
);
190 ax25_std_nr_error_recovery(ax25
);
191 ax25
->state
= AX25_STATE_1
;
196 ax25
->condition
&= ~AX25_COND_PEER_RX_BUSY
;
197 if (type
== AX25_COMMAND
&& pf
)
198 ax25_std_enquiry_response(ax25
);
199 if (ax25_validate_nr(ax25
, nr
)) {
200 ax25_frames_acked(ax25
, nr
);
201 ax25_calculate_rtt(ax25
);
202 ax25_stop_t1timer(ax25
);
203 ax25_start_t3timer(ax25
);
204 ax25_requeue_frames(ax25
);
206 ax25_std_nr_error_recovery(ax25
);
207 ax25
->state
= AX25_STATE_1
;
212 if (!ax25_validate_nr(ax25
, nr
)) {
213 ax25_std_nr_error_recovery(ax25
);
214 ax25
->state
= AX25_STATE_1
;
217 if (ax25
->condition
& AX25_COND_PEER_RX_BUSY
) {
218 ax25_frames_acked(ax25
, nr
);
220 ax25_check_iframes_acked(ax25
, nr
);
222 if (ax25
->condition
& AX25_COND_OWN_RX_BUSY
) {
223 if (pf
) ax25_std_enquiry_response(ax25
);
226 if (ns
== ax25
->vr
) {
227 ax25
->vr
= (ax25
->vr
+ 1) % ax25
->modulus
;
228 queued
= ax25_rx_iframe(ax25
, skb
);
229 if (ax25
->condition
& AX25_COND_OWN_RX_BUSY
)
230 ax25
->vr
= ns
; /* ax25->vr - 1 */
231 ax25
->condition
&= ~AX25_COND_REJECT
;
233 ax25_std_enquiry_response(ax25
);
235 if (!(ax25
->condition
& AX25_COND_ACK_PENDING
)) {
236 ax25
->condition
|= AX25_COND_ACK_PENDING
;
237 ax25_start_t2timer(ax25
);
241 if (ax25
->condition
& AX25_COND_REJECT
) {
242 if (pf
) ax25_std_enquiry_response(ax25
);
244 ax25
->condition
|= AX25_COND_REJECT
;
245 ax25_send_control(ax25
, AX25_REJ
, pf
, AX25_RESPONSE
);
246 ax25
->condition
&= ~AX25_COND_ACK_PENDING
;
253 ax25_std_establish_data_link(ax25
);
254 ax25
->state
= AX25_STATE_1
;
265 * State machine for state 4, Timer Recovery State.
266 * The handling of the timer(s) is in file ax25_std_timer.c
267 * Handling of state 0 and connection release is in ax25.c.
269 static int ax25_std_state4_machine(ax25_cb
*ax25
, struct sk_buff
*skb
, int frametype
, int ns
, int nr
, int pf
, int type
)
276 if (frametype
== AX25_SABM
) {
277 ax25
->modulus
= AX25_MODULUS
;
278 ax25
->window
= ax25
->ax25_dev
->values
[AX25_VALUES_WINDOW
];
280 ax25
->modulus
= AX25_EMODULUS
;
281 ax25
->window
= ax25
->ax25_dev
->values
[AX25_VALUES_EWINDOW
];
283 ax25_send_control(ax25
, AX25_UA
, pf
, AX25_RESPONSE
);
284 ax25_stop_t1timer(ax25
);
285 ax25_stop_t2timer(ax25
);
286 ax25_start_t3timer(ax25
);
287 ax25_start_idletimer(ax25
);
288 ax25
->condition
= 0x00;
292 ax25
->state
= AX25_STATE_3
;
294 ax25_requeue_frames(ax25
);
298 ax25_send_control(ax25
, AX25_UA
, pf
, AX25_RESPONSE
);
299 ax25_disconnect(ax25
, 0);
303 ax25_disconnect(ax25
, ECONNRESET
);
308 if (frametype
== AX25_RR
)
309 ax25
->condition
&= ~AX25_COND_PEER_RX_BUSY
;
311 ax25
->condition
|= AX25_COND_PEER_RX_BUSY
;
312 if (type
== AX25_RESPONSE
&& pf
) {
313 ax25_stop_t1timer(ax25
);
315 if (ax25_validate_nr(ax25
, nr
)) {
316 ax25_frames_acked(ax25
, nr
);
317 if (ax25
->vs
== ax25
->va
) {
318 ax25_start_t3timer(ax25
);
319 ax25
->state
= AX25_STATE_3
;
321 ax25_requeue_frames(ax25
);
324 ax25_std_nr_error_recovery(ax25
);
325 ax25
->state
= AX25_STATE_1
;
329 if (type
== AX25_COMMAND
&& pf
)
330 ax25_std_enquiry_response(ax25
);
331 if (ax25_validate_nr(ax25
, nr
)) {
332 ax25_frames_acked(ax25
, nr
);
334 ax25_std_nr_error_recovery(ax25
);
335 ax25
->state
= AX25_STATE_1
;
340 ax25
->condition
&= ~AX25_COND_PEER_RX_BUSY
;
341 if (pf
&& type
== AX25_RESPONSE
) {
342 ax25_stop_t1timer(ax25
);
344 if (ax25_validate_nr(ax25
, nr
)) {
345 ax25_frames_acked(ax25
, nr
);
346 if (ax25
->vs
== ax25
->va
) {
347 ax25_start_t3timer(ax25
);
348 ax25
->state
= AX25_STATE_3
;
350 ax25_requeue_frames(ax25
);
353 ax25_std_nr_error_recovery(ax25
);
354 ax25
->state
= AX25_STATE_1
;
358 if (type
== AX25_COMMAND
&& pf
)
359 ax25_std_enquiry_response(ax25
);
360 if (ax25_validate_nr(ax25
, nr
)) {
361 ax25_frames_acked(ax25
, nr
);
362 ax25_requeue_frames(ax25
);
364 ax25_std_nr_error_recovery(ax25
);
365 ax25
->state
= AX25_STATE_1
;
370 if (!ax25_validate_nr(ax25
, nr
)) {
371 ax25_std_nr_error_recovery(ax25
);
372 ax25
->state
= AX25_STATE_1
;
375 ax25_frames_acked(ax25
, nr
);
376 if (ax25
->condition
& AX25_COND_OWN_RX_BUSY
) {
378 ax25_std_enquiry_response(ax25
);
381 if (ns
== ax25
->vr
) {
382 ax25
->vr
= (ax25
->vr
+ 1) % ax25
->modulus
;
383 queued
= ax25_rx_iframe(ax25
, skb
);
384 if (ax25
->condition
& AX25_COND_OWN_RX_BUSY
)
385 ax25
->vr
= ns
; /* ax25->vr - 1 */
386 ax25
->condition
&= ~AX25_COND_REJECT
;
388 ax25_std_enquiry_response(ax25
);
390 if (!(ax25
->condition
& AX25_COND_ACK_PENDING
)) {
391 ax25
->condition
|= AX25_COND_ACK_PENDING
;
392 ax25_start_t2timer(ax25
);
396 if (ax25
->condition
& AX25_COND_REJECT
) {
397 if (pf
) ax25_std_enquiry_response(ax25
);
399 ax25
->condition
|= AX25_COND_REJECT
;
400 ax25_send_control(ax25
, AX25_REJ
, pf
, AX25_RESPONSE
);
401 ax25
->condition
&= ~AX25_COND_ACK_PENDING
;
408 ax25_std_establish_data_link(ax25
);
409 ax25
->state
= AX25_STATE_1
;
420 * Higher level upcall for a LAPB frame
422 int ax25_std_frame_in(ax25_cb
*ax25
, struct sk_buff
*skb
, int type
)
424 int queued
= 0, frametype
, ns
, nr
, pf
;
426 frametype
= ax25_decode(ax25
, skb
, &ns
, &nr
, &pf
);
428 switch (ax25
->state
) {
430 queued
= ax25_std_state1_machine(ax25
, skb
, frametype
, pf
, type
);
433 queued
= ax25_std_state2_machine(ax25
, skb
, frametype
, pf
, type
);
436 queued
= ax25_std_state3_machine(ax25
, skb
, frametype
, ns
, nr
, pf
, type
);
439 queued
= ax25_std_state4_machine(ax25
, skb
, frametype
, ns
, nr
, pf
, type
);