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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 | |
6 | * screw up. It might even work. | |
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 processing. | |
19 | * mar/20/00 Daniela Squassoni Disabling/enabling of facilities | |
20 | * negotiation. | |
21 | * jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups | |
22 | * apr/04/15 Shaun Pereira Fast select with no | |
23 | * restriction on response. | |
24 | */ | |
25 | ||
26 | #include <linux/slab.h> | |
27 | #include <linux/kernel.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/skbuff.h> | |
30 | #include <net/sock.h> | |
31 | #include <net/tcp_states.h> | |
32 | #include <net/x25.h> | |
33 | ||
34 | /* | |
35 | * This routine purges all of the queues of frames. | |
36 | */ | |
37 | void x25_clear_queues(struct sock *sk) | |
38 | { | |
39 | struct x25_sock *x25 = x25_sk(sk); | |
40 | ||
41 | skb_queue_purge(&sk->sk_write_queue); | |
42 | skb_queue_purge(&x25->ack_queue); | |
43 | skb_queue_purge(&x25->interrupt_in_queue); | |
44 | skb_queue_purge(&x25->interrupt_out_queue); | |
45 | skb_queue_purge(&x25->fragment_queue); | |
46 | } | |
47 | ||
48 | ||
49 | /* | |
50 | * This routine purges the input queue of those frames that have been | |
51 | * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the | |
52 | * SDL diagram. | |
53 | */ | |
54 | void x25_frames_acked(struct sock *sk, unsigned short nr) | |
55 | { | |
56 | struct sk_buff *skb; | |
57 | struct x25_sock *x25 = x25_sk(sk); | |
58 | int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; | |
59 | ||
60 | /* | |
61 | * Remove all the ack-ed frames from the ack queue. | |
62 | */ | |
63 | if (x25->va != nr) | |
64 | while (skb_peek(&x25->ack_queue) && x25->va != nr) { | |
65 | skb = skb_dequeue(&x25->ack_queue); | |
66 | kfree_skb(skb); | |
67 | x25->va = (x25->va + 1) % modulus; | |
68 | } | |
69 | } | |
70 | ||
71 | void x25_requeue_frames(struct sock *sk) | |
72 | { | |
73 | struct sk_buff *skb, *skb_prev = NULL; | |
74 | ||
75 | /* | |
76 | * Requeue all the un-ack-ed frames on the output queue to be picked | |
77 | * up by x25_kick. This arrangement handles the possibility of an empty | |
78 | * output queue. | |
79 | */ | |
80 | while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) { | |
81 | if (!skb_prev) | |
82 | skb_queue_head(&sk->sk_write_queue, skb); | |
83 | else | |
84 | skb_append(skb_prev, skb, &sk->sk_write_queue); | |
85 | skb_prev = skb; | |
86 | } | |
87 | } | |
88 | ||
89 | /* | |
90 | * Validate that the value of nr is between va and vs. Return true or | |
91 | * false for testing. | |
92 | */ | |
93 | int x25_validate_nr(struct sock *sk, unsigned short nr) | |
94 | { | |
95 | struct x25_sock *x25 = x25_sk(sk); | |
96 | unsigned short vc = x25->va; | |
97 | int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; | |
98 | ||
99 | while (vc != x25->vs) { | |
100 | if (nr == vc) | |
101 | return 1; | |
102 | vc = (vc + 1) % modulus; | |
103 | } | |
104 | ||
105 | return nr == x25->vs ? 1 : 0; | |
106 | } | |
107 | ||
108 | /* | |
109 | * This routine is called when the packet layer internally generates a | |
110 | * control frame. | |
111 | */ | |
112 | void x25_write_internal(struct sock *sk, int frametype) | |
113 | { | |
114 | struct x25_sock *x25 = x25_sk(sk); | |
115 | struct sk_buff *skb; | |
116 | unsigned char *dptr; | |
117 | unsigned char facilities[X25_MAX_FAC_LEN]; | |
118 | unsigned char addresses[1 + X25_ADDR_LEN]; | |
119 | unsigned char lci1, lci2; | |
120 | /* | |
121 | * Default safe frame size. | |
122 | */ | |
123 | int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN; | |
124 | ||
125 | /* | |
126 | * Adjust frame size. | |
127 | */ | |
128 | switch (frametype) { | |
129 | case X25_CALL_REQUEST: | |
130 | len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; | |
131 | break; | |
132 | case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */ | |
133 | if (x25->facilities.reverse & 0x80) { | |
134 | len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; | |
135 | } else { | |
136 | len += 1 + X25_MAX_FAC_LEN; | |
137 | } | |
138 | break; | |
139 | case X25_CLEAR_REQUEST: | |
140 | case X25_RESET_REQUEST: | |
141 | len += 2; | |
142 | break; | |
143 | case X25_RR: | |
144 | case X25_RNR: | |
145 | case X25_REJ: | |
146 | case X25_CLEAR_CONFIRMATION: | |
147 | case X25_INTERRUPT_CONFIRMATION: | |
148 | case X25_RESET_CONFIRMATION: | |
149 | break; | |
150 | default: | |
151 | printk(KERN_ERR "X.25: invalid frame type %02X\n", frametype); | |
152 | return; | |
153 | } | |
154 | ||
155 | if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL) | |
156 | return; | |
157 | ||
158 | /* | |
159 | * Space for Ethernet and 802.2 LLC headers. | |
160 | */ | |
161 | skb_reserve(skb, X25_MAX_L2_LEN); | |
162 | ||
163 | /* | |
164 | * Make space for the GFI and LCI, and fill them in. | |
165 | */ | |
166 | dptr = skb_put(skb, 2); | |
167 | ||
168 | lci1 = (x25->lci >> 8) & 0x0F; | |
169 | lci2 = (x25->lci >> 0) & 0xFF; | |
170 | ||
171 | if (x25->neighbour->extended) { | |
172 | *dptr++ = lci1 | X25_GFI_EXTSEQ; | |
173 | *dptr++ = lci2; | |
174 | } else { | |
175 | *dptr++ = lci1 | X25_GFI_STDSEQ; | |
176 | *dptr++ = lci2; | |
177 | } | |
178 | ||
179 | /* | |
180 | * Now fill in the frame type specific information. | |
181 | */ | |
182 | switch (frametype) { | |
183 | ||
184 | case X25_CALL_REQUEST: | |
185 | dptr = skb_put(skb, 1); | |
186 | *dptr++ = X25_CALL_REQUEST; | |
187 | len = x25_addr_aton(addresses, &x25->dest_addr, | |
188 | &x25->source_addr); | |
189 | dptr = skb_put(skb, len); | |
190 | memcpy(dptr, addresses, len); | |
191 | len = x25_create_facilities(facilities, | |
192 | &x25->facilities, | |
193 | &x25->dte_facilities, | |
194 | x25->neighbour->global_facil_mask); | |
195 | dptr = skb_put(skb, len); | |
196 | memcpy(dptr, facilities, len); | |
197 | dptr = skb_put(skb, x25->calluserdata.cudlength); | |
198 | memcpy(dptr, x25->calluserdata.cuddata, | |
199 | x25->calluserdata.cudlength); | |
200 | x25->calluserdata.cudlength = 0; | |
201 | break; | |
202 | ||
203 | case X25_CALL_ACCEPTED: | |
204 | dptr = skb_put(skb, 2); | |
205 | *dptr++ = X25_CALL_ACCEPTED; | |
206 | *dptr++ = 0x00; /* Address lengths */ | |
207 | len = x25_create_facilities(facilities, | |
208 | &x25->facilities, | |
209 | &x25->dte_facilities, | |
210 | x25->vc_facil_mask); | |
211 | dptr = skb_put(skb, len); | |
212 | memcpy(dptr, facilities, len); | |
213 | ||
214 | /* fast select with no restriction on response | |
215 | allows call user data. Userland must | |
216 | ensure it is ours and not theirs */ | |
217 | if(x25->facilities.reverse & 0x80) { | |
218 | dptr = skb_put(skb, | |
219 | x25->calluserdata.cudlength); | |
220 | memcpy(dptr, x25->calluserdata.cuddata, | |
221 | x25->calluserdata.cudlength); | |
222 | } | |
223 | x25->calluserdata.cudlength = 0; | |
224 | break; | |
225 | ||
226 | case X25_CLEAR_REQUEST: | |
227 | dptr = skb_put(skb, 3); | |
228 | *dptr++ = frametype; | |
229 | *dptr++ = x25->causediag.cause; | |
230 | *dptr++ = x25->causediag.diagnostic; | |
231 | break; | |
232 | ||
233 | case X25_RESET_REQUEST: | |
234 | dptr = skb_put(skb, 3); | |
235 | *dptr++ = frametype; | |
236 | *dptr++ = 0x00; /* XXX */ | |
237 | *dptr++ = 0x00; /* XXX */ | |
238 | break; | |
239 | ||
240 | case X25_RR: | |
241 | case X25_RNR: | |
242 | case X25_REJ: | |
243 | if (x25->neighbour->extended) { | |
244 | dptr = skb_put(skb, 2); | |
245 | *dptr++ = frametype; | |
246 | *dptr++ = (x25->vr << 1) & 0xFE; | |
247 | } else { | |
248 | dptr = skb_put(skb, 1); | |
249 | *dptr = frametype; | |
250 | *dptr++ |= (x25->vr << 5) & 0xE0; | |
251 | } | |
252 | break; | |
253 | ||
254 | case X25_CLEAR_CONFIRMATION: | |
255 | case X25_INTERRUPT_CONFIRMATION: | |
256 | case X25_RESET_CONFIRMATION: | |
257 | dptr = skb_put(skb, 1); | |
258 | *dptr = frametype; | |
259 | break; | |
260 | } | |
261 | ||
262 | x25_transmit_link(skb, x25->neighbour); | |
263 | } | |
264 | ||
265 | /* | |
266 | * Unpick the contents of the passed X.25 Packet Layer frame. | |
267 | */ | |
268 | int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q, | |
269 | int *d, int *m) | |
270 | { | |
271 | struct x25_sock *x25 = x25_sk(sk); | |
272 | unsigned char *frame; | |
273 | ||
274 | if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) | |
275 | return X25_ILLEGAL; | |
276 | frame = skb->data; | |
277 | ||
278 | *ns = *nr = *q = *d = *m = 0; | |
279 | ||
280 | switch (frame[2]) { | |
281 | case X25_CALL_REQUEST: | |
282 | case X25_CALL_ACCEPTED: | |
283 | case X25_CLEAR_REQUEST: | |
284 | case X25_CLEAR_CONFIRMATION: | |
285 | case X25_INTERRUPT: | |
286 | case X25_INTERRUPT_CONFIRMATION: | |
287 | case X25_RESET_REQUEST: | |
288 | case X25_RESET_CONFIRMATION: | |
289 | case X25_RESTART_REQUEST: | |
290 | case X25_RESTART_CONFIRMATION: | |
291 | case X25_REGISTRATION_REQUEST: | |
292 | case X25_REGISTRATION_CONFIRMATION: | |
293 | case X25_DIAGNOSTIC: | |
294 | return frame[2]; | |
295 | } | |
296 | ||
297 | if (x25->neighbour->extended) { | |
298 | if (frame[2] == X25_RR || | |
299 | frame[2] == X25_RNR || | |
300 | frame[2] == X25_REJ) { | |
301 | if (!pskb_may_pull(skb, X25_EXT_MIN_LEN)) | |
302 | return X25_ILLEGAL; | |
303 | frame = skb->data; | |
304 | ||
305 | *nr = (frame[3] >> 1) & 0x7F; | |
306 | return frame[2]; | |
307 | } | |
308 | } else { | |
309 | if ((frame[2] & 0x1F) == X25_RR || | |
310 | (frame[2] & 0x1F) == X25_RNR || | |
311 | (frame[2] & 0x1F) == X25_REJ) { | |
312 | *nr = (frame[2] >> 5) & 0x07; | |
313 | return frame[2] & 0x1F; | |
314 | } | |
315 | } | |
316 | ||
317 | if (x25->neighbour->extended) { | |
318 | if ((frame[2] & 0x01) == X25_DATA) { | |
319 | if (!pskb_may_pull(skb, X25_EXT_MIN_LEN)) | |
320 | return X25_ILLEGAL; | |
321 | frame = skb->data; | |
322 | ||
323 | *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; | |
324 | *d = (frame[0] & X25_D_BIT) == X25_D_BIT; | |
325 | *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT; | |
326 | *nr = (frame[3] >> 1) & 0x7F; | |
327 | *ns = (frame[2] >> 1) & 0x7F; | |
328 | return X25_DATA; | |
329 | } | |
330 | } else { | |
331 | if ((frame[2] & 0x01) == X25_DATA) { | |
332 | *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; | |
333 | *d = (frame[0] & X25_D_BIT) == X25_D_BIT; | |
334 | *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT; | |
335 | *nr = (frame[2] >> 5) & 0x07; | |
336 | *ns = (frame[2] >> 1) & 0x07; | |
337 | return X25_DATA; | |
338 | } | |
339 | } | |
340 | ||
341 | printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n", | |
342 | frame[0], frame[1], frame[2]); | |
343 | ||
344 | return X25_ILLEGAL; | |
345 | } | |
346 | ||
347 | void x25_disconnect(struct sock *sk, int reason, unsigned char cause, | |
348 | unsigned char diagnostic) | |
349 | { | |
350 | struct x25_sock *x25 = x25_sk(sk); | |
351 | ||
352 | x25_clear_queues(sk); | |
353 | x25_stop_timer(sk); | |
354 | ||
355 | x25->lci = 0; | |
356 | x25->state = X25_STATE_0; | |
357 | ||
358 | x25->causediag.cause = cause; | |
359 | x25->causediag.diagnostic = diagnostic; | |
360 | ||
361 | sk->sk_state = TCP_CLOSE; | |
362 | sk->sk_err = reason; | |
363 | sk->sk_shutdown |= SEND_SHUTDOWN; | |
364 | ||
365 | if (!sock_flag(sk, SOCK_DEAD)) { | |
366 | sk->sk_state_change(sk); | |
367 | sock_set_flag(sk, SOCK_DEAD); | |
368 | } | |
369 | } | |
370 | ||
371 | /* | |
372 | * Clear an own-rx-busy condition and tell the peer about this, provided | |
373 | * that there is a significant amount of free receive buffer space available. | |
374 | */ | |
375 | void x25_check_rbuf(struct sock *sk) | |
376 | { | |
377 | struct x25_sock *x25 = x25_sk(sk); | |
378 | ||
379 | if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) && | |
380 | (x25->condition & X25_COND_OWN_RX_BUSY)) { | |
381 | x25->condition &= ~X25_COND_OWN_RX_BUSY; | |
382 | x25->condition &= ~X25_COND_ACK_PENDING; | |
383 | x25->vl = x25->vr; | |
384 | x25_write_internal(sk, X25_RR); | |
385 | x25_stop_timer(sk); | |
386 | } | |
387 | } | |
388 |