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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * X.25 Packet Layer release 002
3 *
4 * This is ALPHA test software. This code may break your machine,
5 * randomly fail to work with new releases, misbehave and/or generally
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +09006 * screw up. It might even work.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
8 * This code REQUIRES 2.1.15 or higher
9 *
10 * This module:
11 * This module is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 *
16 * History
17 * X.25 001 Jonathan Naylor Started coding.
18 * X.25 002 Jonathan Naylor Centralised disconnection code.
19 * New timer architecture.
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +090020 * 2000-03-20 Daniela Squassoni Disabling/enabling of facilities
Linus Torvalds1da177e2005-04-16 15:20:36 -070021 * negotiation.
22 * 2000-11-10 Henner Eisen Check and reset for out-of-sequence
23 * i-frames.
24 */
25
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090026#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/errno.h>
28#include <linux/kernel.h>
29#include <linux/string.h>
30#include <linux/skbuff.h>
31#include <net/sock.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070032#include <net/tcp_states.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <net/x25.h>
34
35static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
36{
37 struct sk_buff *skbo, *skbn = skb;
38 struct x25_sock *x25 = x25_sk(sk);
39
40 if (more) {
41 x25->fraglen += skb->len;
42 skb_queue_tail(&x25->fragment_queue, skb);
43 skb_set_owner_r(skb, sk);
44 return 0;
45 }
46
47 if (!more && x25->fraglen > 0) { /* End of fragment */
48 int len = x25->fraglen + skb->len;
49
50 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
51 kfree_skb(skb);
52 return 1;
53 }
54
55 skb_queue_tail(&x25->fragment_queue, skb);
56
Arnaldo Carvalho de Melobadff6d2007-03-13 13:06:52 -030057 skb_reset_transport_header(skbn);
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
59 skbo = skb_dequeue(&x25->fragment_queue);
Arnaldo Carvalho de Melo1a4e2d02007-03-31 11:55:45 -030060 skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
61 skbo->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 kfree_skb(skbo);
63
64 while ((skbo =
65 skb_dequeue(&x25->fragment_queue)) != NULL) {
66 skb_pull(skbo, (x25->neighbour->extended) ?
67 X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
Arnaldo Carvalho de Melo1a4e2d02007-03-31 11:55:45 -030068 skb_copy_from_linear_data(skbo,
69 skb_put(skbn, skbo->len),
70 skbo->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 kfree_skb(skbo);
72 }
73
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +090074 x25->fraglen = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 }
76
77 skb_set_owner_r(skbn, sk);
78 skb_queue_tail(&sk->sk_receive_queue, skbn);
79 if (!sock_flag(sk, SOCK_DEAD))
80 sk->sk_data_ready(sk, skbn->len);
81
82 return 0;
83}
84
85/*
86 * State machine for state 1, Awaiting Call Accepted State.
87 * The handling of the timer(s) is in file x25_timer.c.
88 * Handling of state 0 and connection release is in af_x25.c.
89 */
90static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
91{
92 struct x25_address source_addr, dest_addr;
John Hughesf5eb9172010-04-07 21:29:25 -070093 int len;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95 switch (frametype) {
96 case X25_CALL_ACCEPTED: {
97 struct x25_sock *x25 = x25_sk(sk);
98
99 x25_stop_timer(sk);
100 x25->condition = 0x00;
101 x25->vs = 0;
102 x25->va = 0;
103 x25->vr = 0;
104 x25->vl = 0;
105 x25->state = X25_STATE_3;
106 sk->sk_state = TCP_ESTABLISHED;
107 /*
108 * Parse the data in the frame.
109 */
110 skb_pull(skb, X25_STD_MIN_LEN);
John Hughesf5eb9172010-04-07 21:29:25 -0700111
112 len = x25_parse_address_block(skb, &source_addr,
113 &dest_addr);
114 if (len > 0)
115 skb_pull(skb, len);
116
117 len = x25_parse_facilities(skb, &x25->facilities,
Shaun Pereiraa64b7b92006-03-22 00:01:31 -0800118 &x25->dte_facilities,
John Hughesf5eb9172010-04-07 21:29:25 -0700119 &x25->vc_facil_mask);
120 if (len > 0)
121 skb_pull(skb, len);
andrew hendrya6331d62010-11-03 12:54:53 +0000122 else
123 return -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 /*
125 * Copy any Call User Data.
126 */
roel kluin091bb8a2009-10-23 05:21:56 +0000127 if (skb->len > 0) {
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -0300128 skb_copy_from_linear_data(skb,
129 x25->calluserdata.cuddata,
130 skb->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 x25->calluserdata.cudlength = skb->len;
132 }
133 if (!sock_flag(sk, SOCK_DEAD))
134 sk->sk_state_change(sk);
135 break;
136 }
137 case X25_CLEAR_REQUEST:
138 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
139 x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
140 break;
141
142 default:
143 break;
144 }
145
146 return 0;
147}
148
149/*
150 * State machine for state 2, Awaiting Clear Confirmation State.
151 * The handling of the timer(s) is in file x25_timer.c
152 * Handling of state 0 and connection release is in af_x25.c.
153 */
154static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
155{
156 switch (frametype) {
157
158 case X25_CLEAR_REQUEST:
159 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
160 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
161 break;
162
163 case X25_CLEAR_CONFIRMATION:
164 x25_disconnect(sk, 0, 0, 0);
165 break;
166
167 default:
168 break;
169 }
170
171 return 0;
172}
173
174/*
175 * State machine for state 3, Connected State.
176 * The handling of the timer(s) is in file x25_timer.c
177 * Handling of state 0 and connection release is in af_x25.c.
178 */
179static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
180{
181 int queued = 0;
182 int modulus;
183 struct x25_sock *x25 = x25_sk(sk);
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +0900184
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
186
187 switch (frametype) {
188
189 case X25_RESET_REQUEST:
190 x25_write_internal(sk, X25_RESET_CONFIRMATION);
191 x25_stop_timer(sk);
192 x25->condition = 0x00;
193 x25->vs = 0;
194 x25->vr = 0;
195 x25->va = 0;
196 x25->vl = 0;
197 x25_requeue_frames(sk);
198 break;
199
200 case X25_CLEAR_REQUEST:
201 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
202 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
203 break;
204
205 case X25_RR:
206 case X25_RNR:
207 if (!x25_validate_nr(sk, nr)) {
208 x25_clear_queues(sk);
209 x25_write_internal(sk, X25_RESET_REQUEST);
210 x25_start_t22timer(sk);
211 x25->condition = 0x00;
212 x25->vs = 0;
213 x25->vr = 0;
214 x25->va = 0;
215 x25->vl = 0;
216 x25->state = X25_STATE_4;
217 } else {
218 x25_frames_acked(sk, nr);
219 if (frametype == X25_RNR) {
220 x25->condition |= X25_COND_PEER_RX_BUSY;
221 } else {
222 x25->condition &= ~X25_COND_PEER_RX_BUSY;
223 }
224 }
225 break;
226
227 case X25_DATA: /* XXX */
228 x25->condition &= ~X25_COND_PEER_RX_BUSY;
229 if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
230 x25_clear_queues(sk);
231 x25_write_internal(sk, X25_RESET_REQUEST);
232 x25_start_t22timer(sk);
233 x25->condition = 0x00;
234 x25->vs = 0;
235 x25->vr = 0;
236 x25->va = 0;
237 x25->vl = 0;
238 x25->state = X25_STATE_4;
239 break;
240 }
241 x25_frames_acked(sk, nr);
242 if (ns == x25->vr) {
243 if (x25_queue_rx_frame(sk, skb, m) == 0) {
244 x25->vr = (x25->vr + 1) % modulus;
245 queued = 1;
246 } else {
247 /* Should never happen */
248 x25_clear_queues(sk);
249 x25_write_internal(sk, X25_RESET_REQUEST);
250 x25_start_t22timer(sk);
251 x25->condition = 0x00;
252 x25->vs = 0;
253 x25->vr = 0;
254 x25->va = 0;
255 x25->vl = 0;
256 x25->state = X25_STATE_4;
257 break;
258 }
259 if (atomic_read(&sk->sk_rmem_alloc) >
Eric Dumazet6bf15742008-01-13 22:27:52 -0800260 (sk->sk_rcvbuf >> 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 x25->condition |= X25_COND_OWN_RX_BUSY;
262 }
263 /*
264 * If the window is full Ack it immediately, else
265 * start the holdback timer.
266 */
267 if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
268 x25->condition &= ~X25_COND_ACK_PENDING;
269 x25_stop_timer(sk);
270 x25_enquiry_response(sk);
271 } else {
272 x25->condition |= X25_COND_ACK_PENDING;
273 x25_start_t2timer(sk);
274 }
275 break;
276
277 case X25_INTERRUPT_CONFIRMATION:
andrew hendryb7792e32010-05-16 23:00:02 +0000278 clear_bit(X25_INTERRUPT_FLAG, &x25->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 break;
280
281 case X25_INTERRUPT:
282 if (sock_flag(sk, SOCK_URGINLINE))
283 queued = !sock_queue_rcv_skb(sk, skb);
284 else {
285 skb_set_owner_r(skb, sk);
286 skb_queue_tail(&x25->interrupt_in_queue, skb);
287 queued = 1;
288 }
289 sk_send_sigurg(sk);
290 x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
291 break;
292
293 default:
294 printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
295 break;
296 }
297
298 return queued;
299}
300
301/*
302 * State machine for state 4, Awaiting Reset Confirmation State.
303 * The handling of the timer(s) is in file x25_timer.c
304 * Handling of state 0 and connection release is in af_x25.c.
305 */
306static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
307{
308 switch (frametype) {
309
310 case X25_RESET_REQUEST:
311 x25_write_internal(sk, X25_RESET_CONFIRMATION);
312 case X25_RESET_CONFIRMATION: {
313 struct x25_sock *x25 = x25_sk(sk);
314
315 x25_stop_timer(sk);
316 x25->condition = 0x00;
317 x25->va = 0;
318 x25->vr = 0;
319 x25->vs = 0;
320 x25->vl = 0;
321 x25->state = X25_STATE_3;
322 x25_requeue_frames(sk);
323 break;
324 }
325 case X25_CLEAR_REQUEST:
326 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
327 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
328 break;
329
330 default:
331 break;
332 }
333
334 return 0;
335}
336
337/* Higher level upcall for a LAPB frame */
338int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
339{
340 struct x25_sock *x25 = x25_sk(sk);
341 int queued = 0, frametype, ns, nr, q, d, m;
342
343 if (x25->state == X25_STATE_0)
344 return 0;
345
346 frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
347
348 switch (x25->state) {
349 case X25_STATE_1:
350 queued = x25_state1_machine(sk, skb, frametype);
351 break;
352 case X25_STATE_2:
353 queued = x25_state2_machine(sk, skb, frametype);
354 break;
355 case X25_STATE_3:
356 queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
357 break;
358 case X25_STATE_4:
359 queued = x25_state4_machine(sk, skb, frametype);
360 break;
361 }
362
363 x25_kick(sk);
364
365 return queued;
366}
367
368int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
369{
370 int queued = x25_process_rx_frame(sk, skb);
371
372 if (!queued)
373 kfree_skb(skb);
374
375 return 0;
376}