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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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 | |
f8e1d201 | 6 | * screw up. It might even work. |
1da177e4 LT |
7 | * |
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. | |
f8e1d201 | 20 | * 2000-03-20 Daniela Squassoni Disabling/enabling of facilities |
1da177e4 LT |
21 | * negotiation. |
22 | * 2000-11-10 Henner Eisen Check and reset for out-of-sequence | |
23 | * i-frames. | |
24 | */ | |
25 | ||
b73e9e3c | 26 | #define pr_fmt(fmt) "X25: " fmt |
27 | ||
5a0e3ad6 | 28 | #include <linux/slab.h> |
1da177e4 LT |
29 | #include <linux/errno.h> |
30 | #include <linux/kernel.h> | |
31 | #include <linux/string.h> | |
32 | #include <linux/skbuff.h> | |
33 | #include <net/sock.h> | |
c752f073 | 34 | #include <net/tcp_states.h> |
1da177e4 LT |
35 | #include <net/x25.h> |
36 | ||
37 | static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more) | |
38 | { | |
39 | struct sk_buff *skbo, *skbn = skb; | |
40 | struct x25_sock *x25 = x25_sk(sk); | |
41 | ||
42 | if (more) { | |
43 | x25->fraglen += skb->len; | |
44 | skb_queue_tail(&x25->fragment_queue, skb); | |
45 | skb_set_owner_r(skb, sk); | |
46 | return 0; | |
47 | } | |
48 | ||
49 | if (!more && x25->fraglen > 0) { /* End of fragment */ | |
50 | int len = x25->fraglen + skb->len; | |
51 | ||
52 | if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){ | |
53 | kfree_skb(skb); | |
54 | return 1; | |
55 | } | |
56 | ||
57 | skb_queue_tail(&x25->fragment_queue, skb); | |
58 | ||
badff6d0 | 59 | skb_reset_transport_header(skbn); |
1da177e4 LT |
60 | |
61 | skbo = skb_dequeue(&x25->fragment_queue); | |
1a4e2d09 ACM |
62 | skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len), |
63 | skbo->len); | |
1da177e4 LT |
64 | kfree_skb(skbo); |
65 | ||
66 | while ((skbo = | |
67 | skb_dequeue(&x25->fragment_queue)) != NULL) { | |
68 | skb_pull(skbo, (x25->neighbour->extended) ? | |
69 | X25_EXT_MIN_LEN : X25_STD_MIN_LEN); | |
1a4e2d09 ACM |
70 | skb_copy_from_linear_data(skbo, |
71 | skb_put(skbn, skbo->len), | |
72 | skbo->len); | |
1da177e4 LT |
73 | kfree_skb(skbo); |
74 | } | |
75 | ||
f8e1d201 | 76 | x25->fraglen = 0; |
1da177e4 LT |
77 | } |
78 | ||
79 | skb_set_owner_r(skbn, sk); | |
80 | skb_queue_tail(&sk->sk_receive_queue, skbn); | |
81 | if (!sock_flag(sk, SOCK_DEAD)) | |
676d2369 | 82 | sk->sk_data_ready(sk); |
1da177e4 LT |
83 | |
84 | return 0; | |
85 | } | |
86 | ||
87 | /* | |
88 | * State machine for state 1, Awaiting Call Accepted State. | |
89 | * The handling of the timer(s) is in file x25_timer.c. | |
90 | * Handling of state 0 and connection release is in af_x25.c. | |
91 | */ | |
92 | static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
93 | { | |
94 | struct x25_address source_addr, dest_addr; | |
f5eb917b | 95 | int len; |
95c30430 | 96 | struct x25_sock *x25 = x25_sk(sk); |
1da177e4 LT |
97 | |
98 | switch (frametype) { | |
fddc5f3e JP |
99 | case X25_CALL_ACCEPTED: { |
100 | ||
101 | x25_stop_timer(sk); | |
102 | x25->condition = 0x00; | |
103 | x25->vs = 0; | |
104 | x25->va = 0; | |
105 | x25->vr = 0; | |
106 | x25->vl = 0; | |
107 | x25->state = X25_STATE_3; | |
108 | sk->sk_state = TCP_ESTABLISHED; | |
109 | /* | |
110 | * Parse the data in the frame. | |
111 | */ | |
cb101ed2 MD |
112 | if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) |
113 | goto out_clear; | |
fddc5f3e JP |
114 | skb_pull(skb, X25_STD_MIN_LEN); |
115 | ||
116 | len = x25_parse_address_block(skb, &source_addr, | |
117 | &dest_addr); | |
118 | if (len > 0) | |
119 | skb_pull(skb, len); | |
120 | else if (len < 0) | |
121 | goto out_clear; | |
122 | ||
123 | len = x25_parse_facilities(skb, &x25->facilities, | |
124 | &x25->dte_facilities, | |
125 | &x25->vc_facil_mask); | |
126 | if (len > 0) | |
127 | skb_pull(skb, len); | |
128 | else if (len < 0) | |
129 | goto out_clear; | |
130 | /* | |
131 | * Copy any Call User Data. | |
132 | */ | |
133 | if (skb->len > 0) { | |
c7fd0d48 MD |
134 | if (skb->len > X25_MAX_CUD_LEN) |
135 | goto out_clear; | |
136 | ||
cb101ed2 MD |
137 | skb_copy_bits(skb, 0, x25->calluserdata.cuddata, |
138 | skb->len); | |
fddc5f3e | 139 | x25->calluserdata.cudlength = skb->len; |
1da177e4 | 140 | } |
fddc5f3e JP |
141 | if (!sock_flag(sk, SOCK_DEAD)) |
142 | sk->sk_state_change(sk); | |
143 | break; | |
144 | } | |
b020fcf6 MS |
145 | case X25_CALL_REQUEST: |
146 | /* call collision */ | |
147 | x25->causediag.cause = 0x01; | |
148 | x25->causediag.diagnostic = 0x48; | |
149 | ||
150 | x25_write_internal(sk, X25_CLEAR_REQUEST); | |
151 | x25_disconnect(sk, EISCONN, 0x01, 0x48); | |
152 | break; | |
153 | ||
fddc5f3e | 154 | case X25_CLEAR_REQUEST: |
cb101ed2 MD |
155 | if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) |
156 | goto out_clear; | |
157 | ||
fddc5f3e JP |
158 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); |
159 | x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]); | |
160 | break; | |
1da177e4 | 161 | |
fddc5f3e JP |
162 | default: |
163 | break; | |
1da177e4 LT |
164 | } |
165 | ||
166 | return 0; | |
95c30430 | 167 | |
168 | out_clear: | |
169 | x25_write_internal(sk, X25_CLEAR_REQUEST); | |
170 | x25->state = X25_STATE_2; | |
171 | x25_start_t23timer(sk); | |
172 | return 0; | |
1da177e4 LT |
173 | } |
174 | ||
175 | /* | |
176 | * State machine for state 2, Awaiting Clear Confirmation State. | |
177 | * The handling of the timer(s) is in file x25_timer.c | |
178 | * Handling of state 0 and connection release is in af_x25.c. | |
179 | */ | |
180 | static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
181 | { | |
182 | switch (frametype) { | |
183 | ||
184 | case X25_CLEAR_REQUEST: | |
cb101ed2 MD |
185 | if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) |
186 | goto out_clear; | |
187 | ||
1da177e4 LT |
188 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); |
189 | x25_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
190 | break; | |
191 | ||
192 | case X25_CLEAR_CONFIRMATION: | |
193 | x25_disconnect(sk, 0, 0, 0); | |
194 | break; | |
195 | ||
196 | default: | |
197 | break; | |
198 | } | |
199 | ||
200 | return 0; | |
cb101ed2 MD |
201 | |
202 | out_clear: | |
203 | x25_write_internal(sk, X25_CLEAR_REQUEST); | |
204 | x25_start_t23timer(sk); | |
205 | return 0; | |
1da177e4 LT |
206 | } |
207 | ||
208 | /* | |
209 | * State machine for state 3, Connected State. | |
210 | * The handling of the timer(s) is in file x25_timer.c | |
211 | * Handling of state 0 and connection release is in af_x25.c. | |
212 | */ | |
213 | static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m) | |
214 | { | |
215 | int queued = 0; | |
216 | int modulus; | |
217 | struct x25_sock *x25 = x25_sk(sk); | |
f8e1d201 | 218 | |
1da177e4 LT |
219 | modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS; |
220 | ||
221 | switch (frametype) { | |
222 | ||
223 | case X25_RESET_REQUEST: | |
224 | x25_write_internal(sk, X25_RESET_CONFIRMATION); | |
225 | x25_stop_timer(sk); | |
226 | x25->condition = 0x00; | |
227 | x25->vs = 0; | |
228 | x25->vr = 0; | |
229 | x25->va = 0; | |
230 | x25->vl = 0; | |
231 | x25_requeue_frames(sk); | |
232 | break; | |
233 | ||
234 | case X25_CLEAR_REQUEST: | |
cb101ed2 MD |
235 | if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) |
236 | goto out_clear; | |
237 | ||
1da177e4 LT |
238 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); |
239 | x25_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
240 | break; | |
241 | ||
242 | case X25_RR: | |
243 | case X25_RNR: | |
244 | if (!x25_validate_nr(sk, nr)) { | |
245 | x25_clear_queues(sk); | |
246 | x25_write_internal(sk, X25_RESET_REQUEST); | |
247 | x25_start_t22timer(sk); | |
248 | x25->condition = 0x00; | |
249 | x25->vs = 0; | |
250 | x25->vr = 0; | |
251 | x25->va = 0; | |
252 | x25->vl = 0; | |
253 | x25->state = X25_STATE_4; | |
254 | } else { | |
255 | x25_frames_acked(sk, nr); | |
256 | if (frametype == X25_RNR) { | |
257 | x25->condition |= X25_COND_PEER_RX_BUSY; | |
258 | } else { | |
259 | x25->condition &= ~X25_COND_PEER_RX_BUSY; | |
260 | } | |
261 | } | |
262 | break; | |
263 | ||
264 | case X25_DATA: /* XXX */ | |
265 | x25->condition &= ~X25_COND_PEER_RX_BUSY; | |
266 | if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) { | |
267 | x25_clear_queues(sk); | |
268 | x25_write_internal(sk, X25_RESET_REQUEST); | |
269 | x25_start_t22timer(sk); | |
270 | x25->condition = 0x00; | |
271 | x25->vs = 0; | |
272 | x25->vr = 0; | |
273 | x25->va = 0; | |
274 | x25->vl = 0; | |
275 | x25->state = X25_STATE_4; | |
276 | break; | |
277 | } | |
278 | x25_frames_acked(sk, nr); | |
279 | if (ns == x25->vr) { | |
280 | if (x25_queue_rx_frame(sk, skb, m) == 0) { | |
281 | x25->vr = (x25->vr + 1) % modulus; | |
282 | queued = 1; | |
283 | } else { | |
284 | /* Should never happen */ | |
285 | x25_clear_queues(sk); | |
286 | x25_write_internal(sk, X25_RESET_REQUEST); | |
287 | x25_start_t22timer(sk); | |
288 | x25->condition = 0x00; | |
289 | x25->vs = 0; | |
290 | x25->vr = 0; | |
291 | x25->va = 0; | |
292 | x25->vl = 0; | |
293 | x25->state = X25_STATE_4; | |
294 | break; | |
295 | } | |
296 | if (atomic_read(&sk->sk_rmem_alloc) > | |
6bf1574e | 297 | (sk->sk_rcvbuf >> 1)) |
1da177e4 LT |
298 | x25->condition |= X25_COND_OWN_RX_BUSY; |
299 | } | |
300 | /* | |
301 | * If the window is full Ack it immediately, else | |
302 | * start the holdback timer. | |
303 | */ | |
304 | if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) { | |
305 | x25->condition &= ~X25_COND_ACK_PENDING; | |
306 | x25_stop_timer(sk); | |
307 | x25_enquiry_response(sk); | |
308 | } else { | |
309 | x25->condition |= X25_COND_ACK_PENDING; | |
310 | x25_start_t2timer(sk); | |
311 | } | |
312 | break; | |
313 | ||
314 | case X25_INTERRUPT_CONFIRMATION: | |
b7792e34 | 315 | clear_bit(X25_INTERRUPT_FLAG, &x25->flags); |
1da177e4 LT |
316 | break; |
317 | ||
318 | case X25_INTERRUPT: | |
319 | if (sock_flag(sk, SOCK_URGINLINE)) | |
320 | queued = !sock_queue_rcv_skb(sk, skb); | |
321 | else { | |
322 | skb_set_owner_r(skb, sk); | |
323 | skb_queue_tail(&x25->interrupt_in_queue, skb); | |
324 | queued = 1; | |
325 | } | |
326 | sk_send_sigurg(sk); | |
327 | x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION); | |
328 | break; | |
329 | ||
330 | default: | |
b73e9e3c | 331 | pr_warn("unknown %02X in state 3\n", frametype); |
1da177e4 LT |
332 | break; |
333 | } | |
334 | ||
335 | return queued; | |
cb101ed2 MD |
336 | |
337 | out_clear: | |
338 | x25_write_internal(sk, X25_CLEAR_REQUEST); | |
339 | x25->state = X25_STATE_2; | |
340 | x25_start_t23timer(sk); | |
341 | return 0; | |
1da177e4 LT |
342 | } |
343 | ||
344 | /* | |
345 | * State machine for state 4, Awaiting Reset Confirmation State. | |
346 | * The handling of the timer(s) is in file x25_timer.c | |
347 | * Handling of state 0 and connection release is in af_x25.c. | |
348 | */ | |
349 | static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype) | |
350 | { | |
cb101ed2 MD |
351 | struct x25_sock *x25 = x25_sk(sk); |
352 | ||
1da177e4 LT |
353 | switch (frametype) { |
354 | ||
355 | case X25_RESET_REQUEST: | |
356 | x25_write_internal(sk, X25_RESET_CONFIRMATION); | |
0cea8e28 | 357 | /* fall through */ |
1da177e4 | 358 | case X25_RESET_CONFIRMATION: { |
1da177e4 LT |
359 | x25_stop_timer(sk); |
360 | x25->condition = 0x00; | |
361 | x25->va = 0; | |
362 | x25->vr = 0; | |
363 | x25->vs = 0; | |
364 | x25->vl = 0; | |
365 | x25->state = X25_STATE_3; | |
366 | x25_requeue_frames(sk); | |
367 | break; | |
368 | } | |
369 | case X25_CLEAR_REQUEST: | |
cb101ed2 MD |
370 | if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2)) |
371 | goto out_clear; | |
372 | ||
1da177e4 LT |
373 | x25_write_internal(sk, X25_CLEAR_CONFIRMATION); |
374 | x25_disconnect(sk, 0, skb->data[3], skb->data[4]); | |
375 | break; | |
376 | ||
377 | default: | |
378 | break; | |
379 | } | |
380 | ||
381 | return 0; | |
cb101ed2 MD |
382 | |
383 | out_clear: | |
384 | x25_write_internal(sk, X25_CLEAR_REQUEST); | |
385 | x25->state = X25_STATE_2; | |
386 | x25_start_t23timer(sk); | |
387 | return 0; | |
1da177e4 LT |
388 | } |
389 | ||
390 | /* Higher level upcall for a LAPB frame */ | |
391 | int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb) | |
392 | { | |
393 | struct x25_sock *x25 = x25_sk(sk); | |
394 | int queued = 0, frametype, ns, nr, q, d, m; | |
395 | ||
396 | if (x25->state == X25_STATE_0) | |
397 | return 0; | |
398 | ||
399 | frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m); | |
400 | ||
401 | switch (x25->state) { | |
fddc5f3e JP |
402 | case X25_STATE_1: |
403 | queued = x25_state1_machine(sk, skb, frametype); | |
404 | break; | |
405 | case X25_STATE_2: | |
406 | queued = x25_state2_machine(sk, skb, frametype); | |
407 | break; | |
408 | case X25_STATE_3: | |
409 | queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m); | |
410 | break; | |
411 | case X25_STATE_4: | |
412 | queued = x25_state4_machine(sk, skb, frametype); | |
413 | break; | |
1da177e4 LT |
414 | } |
415 | ||
416 | x25_kick(sk); | |
417 | ||
418 | return queued; | |
419 | } | |
420 | ||
421 | int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
422 | { | |
423 | int queued = x25_process_rx_frame(sk, skb); | |
424 | ||
425 | if (!queued) | |
426 | kfree_skb(skb); | |
427 | ||
428 | return 0; | |
429 | } |