blob: 63178961efac00488d36e7c8fc3d21f00e036e2e [file] [log] [blame]
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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 /*
123 * Copy any Call User Data.
124 */
roel kluin091bb8a2009-10-23 05:21:56 +0000125 if (skb->len > 0) {
Arnaldo Carvalho de Melod626f622007-03-27 18:55:52 -0300126 skb_copy_from_linear_data(skb,
127 x25->calluserdata.cuddata,
128 skb->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 x25->calluserdata.cudlength = skb->len;
130 }
131 if (!sock_flag(sk, SOCK_DEAD))
132 sk->sk_state_change(sk);
133 break;
134 }
135 case X25_CLEAR_REQUEST:
136 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
137 x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
138 break;
139
140 default:
141 break;
142 }
143
144 return 0;
145}
146
147/*
148 * State machine for state 2, Awaiting Clear Confirmation State.
149 * The handling of the timer(s) is in file x25_timer.c
150 * Handling of state 0 and connection release is in af_x25.c.
151 */
152static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
153{
154 switch (frametype) {
155
156 case X25_CLEAR_REQUEST:
157 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
158 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
159 break;
160
161 case X25_CLEAR_CONFIRMATION:
162 x25_disconnect(sk, 0, 0, 0);
163 break;
164
165 default:
166 break;
167 }
168
169 return 0;
170}
171
172/*
173 * State machine for state 3, Connected State.
174 * The handling of the timer(s) is in file x25_timer.c
175 * Handling of state 0 and connection release is in af_x25.c.
176 */
177static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
178{
179 int queued = 0;
180 int modulus;
181 struct x25_sock *x25 = x25_sk(sk);
YOSHIFUJI Hideakif8e1d2012007-02-09 23:25:27 +0900182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
184
185 switch (frametype) {
186
187 case X25_RESET_REQUEST:
188 x25_write_internal(sk, X25_RESET_CONFIRMATION);
189 x25_stop_timer(sk);
190 x25->condition = 0x00;
191 x25->vs = 0;
192 x25->vr = 0;
193 x25->va = 0;
194 x25->vl = 0;
195 x25_requeue_frames(sk);
196 break;
197
198 case X25_CLEAR_REQUEST:
199 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
200 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
201 break;
202
203 case X25_RR:
204 case X25_RNR:
205 if (!x25_validate_nr(sk, nr)) {
206 x25_clear_queues(sk);
207 x25_write_internal(sk, X25_RESET_REQUEST);
208 x25_start_t22timer(sk);
209 x25->condition = 0x00;
210 x25->vs = 0;
211 x25->vr = 0;
212 x25->va = 0;
213 x25->vl = 0;
214 x25->state = X25_STATE_4;
215 } else {
216 x25_frames_acked(sk, nr);
217 if (frametype == X25_RNR) {
218 x25->condition |= X25_COND_PEER_RX_BUSY;
219 } else {
220 x25->condition &= ~X25_COND_PEER_RX_BUSY;
221 }
222 }
223 break;
224
225 case X25_DATA: /* XXX */
226 x25->condition &= ~X25_COND_PEER_RX_BUSY;
227 if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
228 x25_clear_queues(sk);
229 x25_write_internal(sk, X25_RESET_REQUEST);
230 x25_start_t22timer(sk);
231 x25->condition = 0x00;
232 x25->vs = 0;
233 x25->vr = 0;
234 x25->va = 0;
235 x25->vl = 0;
236 x25->state = X25_STATE_4;
237 break;
238 }
239 x25_frames_acked(sk, nr);
240 if (ns == x25->vr) {
241 if (x25_queue_rx_frame(sk, skb, m) == 0) {
242 x25->vr = (x25->vr + 1) % modulus;
243 queued = 1;
244 } else {
245 /* Should never happen */
246 x25_clear_queues(sk);
247 x25_write_internal(sk, X25_RESET_REQUEST);
248 x25_start_t22timer(sk);
249 x25->condition = 0x00;
250 x25->vs = 0;
251 x25->vr = 0;
252 x25->va = 0;
253 x25->vl = 0;
254 x25->state = X25_STATE_4;
255 break;
256 }
257 if (atomic_read(&sk->sk_rmem_alloc) >
Eric Dumazet6bf15742008-01-13 22:27:52 -0800258 (sk->sk_rcvbuf >> 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 x25->condition |= X25_COND_OWN_RX_BUSY;
260 }
261 /*
262 * If the window is full Ack it immediately, else
263 * start the holdback timer.
264 */
265 if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
266 x25->condition &= ~X25_COND_ACK_PENDING;
267 x25_stop_timer(sk);
268 x25_enquiry_response(sk);
269 } else {
270 x25->condition |= X25_COND_ACK_PENDING;
271 x25_start_t2timer(sk);
272 }
273 break;
274
275 case X25_INTERRUPT_CONFIRMATION:
andrew hendryb7792e32010-05-16 23:00:02 +0000276 clear_bit(X25_INTERRUPT_FLAG, &x25->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 break;
278
279 case X25_INTERRUPT:
280 if (sock_flag(sk, SOCK_URGINLINE))
281 queued = !sock_queue_rcv_skb(sk, skb);
282 else {
283 skb_set_owner_r(skb, sk);
284 skb_queue_tail(&x25->interrupt_in_queue, skb);
285 queued = 1;
286 }
287 sk_send_sigurg(sk);
288 x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
289 break;
290
291 default:
292 printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
293 break;
294 }
295
296 return queued;
297}
298
299/*
300 * State machine for state 4, Awaiting Reset Confirmation State.
301 * The handling of the timer(s) is in file x25_timer.c
302 * Handling of state 0 and connection release is in af_x25.c.
303 */
304static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
305{
306 switch (frametype) {
307
308 case X25_RESET_REQUEST:
309 x25_write_internal(sk, X25_RESET_CONFIRMATION);
310 case X25_RESET_CONFIRMATION: {
311 struct x25_sock *x25 = x25_sk(sk);
312
313 x25_stop_timer(sk);
314 x25->condition = 0x00;
315 x25->va = 0;
316 x25->vr = 0;
317 x25->vs = 0;
318 x25->vl = 0;
319 x25->state = X25_STATE_3;
320 x25_requeue_frames(sk);
321 break;
322 }
323 case X25_CLEAR_REQUEST:
324 x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
325 x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
326 break;
327
328 default:
329 break;
330 }
331
332 return 0;
333}
334
335/* Higher level upcall for a LAPB frame */
336int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
337{
338 struct x25_sock *x25 = x25_sk(sk);
339 int queued = 0, frametype, ns, nr, q, d, m;
340
341 if (x25->state == X25_STATE_0)
342 return 0;
343
344 frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
345
346 switch (x25->state) {
347 case X25_STATE_1:
348 queued = x25_state1_machine(sk, skb, frametype);
349 break;
350 case X25_STATE_2:
351 queued = x25_state2_machine(sk, skb, frametype);
352 break;
353 case X25_STATE_3:
354 queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
355 break;
356 case X25_STATE_4:
357 queued = x25_state4_machine(sk, skb, frametype);
358 break;
359 }
360
361 x25_kick(sk);
362
363 return queued;
364}
365
366int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
367{
368 int queued = x25_process_rx_frame(sk, skb);
369
370 if (!queued)
371 kfree_skb(skb);
372
373 return 0;
374}