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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 | |
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 | |
ebc3f64b SP |
22 | * apr/04/15 Shaun Pereira Fast select with no |
23 | * restriction on response. | |
1da177e4 LT |
24 | */ |
25 | ||
b73e9e3c | 26 | #define pr_fmt(fmt) "X25: " fmt |
27 | ||
5a0e3ad6 | 28 | #include <linux/slab.h> |
1da177e4 LT |
29 | #include <linux/kernel.h> |
30 | #include <linux/string.h> | |
31 | #include <linux/skbuff.h> | |
32 | #include <net/sock.h> | |
c752f073 | 33 | #include <net/tcp_states.h> |
1da177e4 LT |
34 | #include <net/x25.h> |
35 | ||
36 | /* | |
37 | * This routine purges all of the queues of frames. | |
38 | */ | |
39 | void x25_clear_queues(struct sock *sk) | |
40 | { | |
41 | struct x25_sock *x25 = x25_sk(sk); | |
42 | ||
43 | skb_queue_purge(&sk->sk_write_queue); | |
44 | skb_queue_purge(&x25->ack_queue); | |
45 | skb_queue_purge(&x25->interrupt_in_queue); | |
46 | skb_queue_purge(&x25->interrupt_out_queue); | |
47 | skb_queue_purge(&x25->fragment_queue); | |
48 | } | |
49 | ||
50 | ||
51 | /* | |
52 | * This routine purges the input queue of those frames that have been | |
53 | * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the | |
54 | * SDL diagram. | |
55 | */ | |
56 | void x25_frames_acked(struct sock *sk, unsigned short nr) | |
57 | { | |
58 | struct sk_buff *skb; | |
59 | struct x25_sock *x25 = x25_sk(sk); | |
60 | int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; | |
61 | ||
62 | /* | |
63 | * Remove all the ack-ed frames from the ack queue. | |
64 | */ | |
65 | if (x25->va != nr) | |
66 | while (skb_peek(&x25->ack_queue) && x25->va != nr) { | |
67 | skb = skb_dequeue(&x25->ack_queue); | |
68 | kfree_skb(skb); | |
69 | x25->va = (x25->va + 1) % modulus; | |
70 | } | |
71 | } | |
72 | ||
73 | void x25_requeue_frames(struct sock *sk) | |
74 | { | |
75 | struct sk_buff *skb, *skb_prev = NULL; | |
76 | ||
77 | /* | |
78 | * Requeue all the un-ack-ed frames on the output queue to be picked | |
79 | * up by x25_kick. This arrangement handles the possibility of an empty | |
80 | * output queue. | |
81 | */ | |
82 | while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) { | |
83 | if (!skb_prev) | |
84 | skb_queue_head(&sk->sk_write_queue, skb); | |
85 | else | |
8728b834 | 86 | skb_append(skb_prev, skb, &sk->sk_write_queue); |
1da177e4 LT |
87 | skb_prev = skb; |
88 | } | |
89 | } | |
90 | ||
91 | /* | |
92 | * Validate that the value of nr is between va and vs. Return true or | |
93 | * false for testing. | |
94 | */ | |
95 | int x25_validate_nr(struct sock *sk, unsigned short nr) | |
96 | { | |
97 | struct x25_sock *x25 = x25_sk(sk); | |
98 | unsigned short vc = x25->va; | |
99 | int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS; | |
100 | ||
101 | while (vc != x25->vs) { | |
102 | if (nr == vc) | |
103 | return 1; | |
104 | vc = (vc + 1) % modulus; | |
105 | } | |
106 | ||
107 | return nr == x25->vs ? 1 : 0; | |
108 | } | |
109 | ||
110 | /* | |
111 | * This routine is called when the packet layer internally generates a | |
112 | * control frame. | |
113 | */ | |
114 | void x25_write_internal(struct sock *sk, int frametype) | |
115 | { | |
116 | struct x25_sock *x25 = x25_sk(sk); | |
117 | struct sk_buff *skb; | |
118 | unsigned char *dptr; | |
119 | unsigned char facilities[X25_MAX_FAC_LEN]; | |
120 | unsigned char addresses[1 + X25_ADDR_LEN]; | |
121 | unsigned char lci1, lci2; | |
122 | /* | |
123 | * Default safe frame size. | |
124 | */ | |
125 | int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN; | |
126 | ||
127 | /* | |
128 | * Adjust frame size. | |
129 | */ | |
130 | switch (frametype) { | |
fddc5f3e JP |
131 | case X25_CALL_REQUEST: |
132 | len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; | |
133 | break; | |
134 | case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */ | |
135 | if (x25->facilities.reverse & 0x80) { | |
136 | len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; | |
137 | } else { | |
138 | len += 1 + X25_MAX_FAC_LEN; | |
139 | } | |
140 | break; | |
141 | case X25_CLEAR_REQUEST: | |
142 | case X25_RESET_REQUEST: | |
143 | len += 2; | |
144 | break; | |
145 | case X25_RR: | |
146 | case X25_RNR: | |
147 | case X25_REJ: | |
148 | case X25_CLEAR_CONFIRMATION: | |
149 | case X25_INTERRUPT_CONFIRMATION: | |
150 | case X25_RESET_CONFIRMATION: | |
151 | break; | |
152 | default: | |
b73e9e3c | 153 | pr_err("invalid frame type %02X\n", frametype); |
fddc5f3e | 154 | return; |
1da177e4 LT |
155 | } |
156 | ||
157 | if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL) | |
158 | return; | |
159 | ||
160 | /* | |
161 | * Space for Ethernet and 802.2 LLC headers. | |
162 | */ | |
163 | skb_reserve(skb, X25_MAX_L2_LEN); | |
164 | ||
165 | /* | |
166 | * Make space for the GFI and LCI, and fill them in. | |
167 | */ | |
168 | dptr = skb_put(skb, 2); | |
169 | ||
170 | lci1 = (x25->lci >> 8) & 0x0F; | |
171 | lci2 = (x25->lci >> 0) & 0xFF; | |
172 | ||
173 | if (x25->neighbour->extended) { | |
174 | *dptr++ = lci1 | X25_GFI_EXTSEQ; | |
175 | *dptr++ = lci2; | |
176 | } else { | |
177 | *dptr++ = lci1 | X25_GFI_STDSEQ; | |
178 | *dptr++ = lci2; | |
179 | } | |
180 | ||
181 | /* | |
182 | * Now fill in the frame type specific information. | |
183 | */ | |
184 | switch (frametype) { | |
185 | ||
186 | case X25_CALL_REQUEST: | |
187 | dptr = skb_put(skb, 1); | |
188 | *dptr++ = X25_CALL_REQUEST; | |
189 | len = x25_addr_aton(addresses, &x25->dest_addr, | |
190 | &x25->source_addr); | |
191 | dptr = skb_put(skb, len); | |
192 | memcpy(dptr, addresses, len); | |
193 | len = x25_create_facilities(facilities, | |
a64b7b93 SP |
194 | &x25->facilities, |
195 | &x25->dte_facilities, | |
196 | x25->neighbour->global_facil_mask); | |
1da177e4 LT |
197 | dptr = skb_put(skb, len); |
198 | memcpy(dptr, facilities, len); | |
199 | dptr = skb_put(skb, x25->calluserdata.cudlength); | |
200 | memcpy(dptr, x25->calluserdata.cuddata, | |
201 | x25->calluserdata.cudlength); | |
202 | x25->calluserdata.cudlength = 0; | |
203 | break; | |
204 | ||
205 | case X25_CALL_ACCEPTED: | |
206 | dptr = skb_put(skb, 2); | |
207 | *dptr++ = X25_CALL_ACCEPTED; | |
208 | *dptr++ = 0x00; /* Address lengths */ | |
209 | len = x25_create_facilities(facilities, | |
210 | &x25->facilities, | |
a64b7b93 | 211 | &x25->dte_facilities, |
1da177e4 LT |
212 | x25->vc_facil_mask); |
213 | dptr = skb_put(skb, len); | |
214 | memcpy(dptr, facilities, len); | |
ebc3f64b SP |
215 | |
216 | /* fast select with no restriction on response | |
217 | allows call user data. Userland must | |
218 | ensure it is ours and not theirs */ | |
219 | if(x25->facilities.reverse & 0x80) { | |
220 | dptr = skb_put(skb, | |
221 | x25->calluserdata.cudlength); | |
222 | memcpy(dptr, x25->calluserdata.cuddata, | |
223 | x25->calluserdata.cudlength); | |
224 | } | |
1da177e4 LT |
225 | x25->calluserdata.cudlength = 0; |
226 | break; | |
227 | ||
228 | case X25_CLEAR_REQUEST: | |
386e50cc AH |
229 | dptr = skb_put(skb, 3); |
230 | *dptr++ = frametype; | |
231 | *dptr++ = x25->causediag.cause; | |
232 | *dptr++ = x25->causediag.diagnostic; | |
233 | break; | |
234 | ||
1da177e4 LT |
235 | case X25_RESET_REQUEST: |
236 | dptr = skb_put(skb, 3); | |
237 | *dptr++ = frametype; | |
238 | *dptr++ = 0x00; /* XXX */ | |
239 | *dptr++ = 0x00; /* XXX */ | |
240 | break; | |
241 | ||
242 | case X25_RR: | |
243 | case X25_RNR: | |
244 | case X25_REJ: | |
245 | if (x25->neighbour->extended) { | |
246 | dptr = skb_put(skb, 2); | |
247 | *dptr++ = frametype; | |
248 | *dptr++ = (x25->vr << 1) & 0xFE; | |
249 | } else { | |
250 | dptr = skb_put(skb, 1); | |
251 | *dptr = frametype; | |
252 | *dptr++ |= (x25->vr << 5) & 0xE0; | |
253 | } | |
254 | break; | |
255 | ||
256 | case X25_CLEAR_CONFIRMATION: | |
257 | case X25_INTERRUPT_CONFIRMATION: | |
258 | case X25_RESET_CONFIRMATION: | |
259 | dptr = skb_put(skb, 1); | |
260 | *dptr = frametype; | |
261 | break; | |
262 | } | |
263 | ||
264 | x25_transmit_link(skb, x25->neighbour); | |
265 | } | |
266 | ||
267 | /* | |
268 | * Unpick the contents of the passed X.25 Packet Layer frame. | |
269 | */ | |
270 | int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q, | |
271 | int *d, int *m) | |
272 | { | |
273 | struct x25_sock *x25 = x25_sk(sk); | |
cb101ed2 MD |
274 | unsigned char *frame; |
275 | ||
276 | if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) | |
277 | return X25_ILLEGAL; | |
278 | frame = skb->data; | |
1da177e4 LT |
279 | |
280 | *ns = *nr = *q = *d = *m = 0; | |
281 | ||
282 | switch (frame[2]) { | |
fddc5f3e JP |
283 | case X25_CALL_REQUEST: |
284 | case X25_CALL_ACCEPTED: | |
285 | case X25_CLEAR_REQUEST: | |
286 | case X25_CLEAR_CONFIRMATION: | |
287 | case X25_INTERRUPT: | |
288 | case X25_INTERRUPT_CONFIRMATION: | |
289 | case X25_RESET_REQUEST: | |
290 | case X25_RESET_CONFIRMATION: | |
291 | case X25_RESTART_REQUEST: | |
292 | case X25_RESTART_CONFIRMATION: | |
293 | case X25_REGISTRATION_REQUEST: | |
294 | case X25_REGISTRATION_CONFIRMATION: | |
295 | case X25_DIAGNOSTIC: | |
296 | return frame[2]; | |
1da177e4 LT |
297 | } |
298 | ||
299 | if (x25->neighbour->extended) { | |
300 | if (frame[2] == X25_RR || | |
301 | frame[2] == X25_RNR || | |
302 | frame[2] == X25_REJ) { | |
cb101ed2 MD |
303 | if (!pskb_may_pull(skb, X25_EXT_MIN_LEN)) |
304 | return X25_ILLEGAL; | |
305 | frame = skb->data; | |
306 | ||
1da177e4 LT |
307 | *nr = (frame[3] >> 1) & 0x7F; |
308 | return frame[2]; | |
309 | } | |
310 | } else { | |
311 | if ((frame[2] & 0x1F) == X25_RR || | |
312 | (frame[2] & 0x1F) == X25_RNR || | |
313 | (frame[2] & 0x1F) == X25_REJ) { | |
314 | *nr = (frame[2] >> 5) & 0x07; | |
315 | return frame[2] & 0x1F; | |
316 | } | |
317 | } | |
318 | ||
319 | if (x25->neighbour->extended) { | |
320 | if ((frame[2] & 0x01) == X25_DATA) { | |
cb101ed2 MD |
321 | if (!pskb_may_pull(skb, X25_EXT_MIN_LEN)) |
322 | return X25_ILLEGAL; | |
323 | frame = skb->data; | |
324 | ||
1da177e4 LT |
325 | *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; |
326 | *d = (frame[0] & X25_D_BIT) == X25_D_BIT; | |
327 | *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT; | |
328 | *nr = (frame[3] >> 1) & 0x7F; | |
329 | *ns = (frame[2] >> 1) & 0x7F; | |
330 | return X25_DATA; | |
331 | } | |
332 | } else { | |
333 | if ((frame[2] & 0x01) == X25_DATA) { | |
334 | *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; | |
335 | *d = (frame[0] & X25_D_BIT) == X25_D_BIT; | |
336 | *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT; | |
337 | *nr = (frame[2] >> 5) & 0x07; | |
338 | *ns = (frame[2] >> 1) & 0x07; | |
339 | return X25_DATA; | |
340 | } | |
341 | } | |
342 | ||
b73e9e3c | 343 | pr_debug("invalid PLP frame %02X %02X %02X\n", |
1da177e4 LT |
344 | frame[0], frame[1], frame[2]); |
345 | ||
346 | return X25_ILLEGAL; | |
347 | } | |
348 | ||
349 | void x25_disconnect(struct sock *sk, int reason, unsigned char cause, | |
350 | unsigned char diagnostic) | |
351 | { | |
352 | struct x25_sock *x25 = x25_sk(sk); | |
353 | ||
354 | x25_clear_queues(sk); | |
355 | x25_stop_timer(sk); | |
356 | ||
357 | x25->lci = 0; | |
358 | x25->state = X25_STATE_0; | |
359 | ||
360 | x25->causediag.cause = cause; | |
361 | x25->causediag.diagnostic = diagnostic; | |
362 | ||
363 | sk->sk_state = TCP_CLOSE; | |
364 | sk->sk_err = reason; | |
365 | sk->sk_shutdown |= SEND_SHUTDOWN; | |
366 | ||
367 | if (!sock_flag(sk, SOCK_DEAD)) { | |
368 | sk->sk_state_change(sk); | |
369 | sock_set_flag(sk, SOCK_DEAD); | |
370 | } | |
371 | } | |
372 | ||
373 | /* | |
374 | * Clear an own-rx-busy condition and tell the peer about this, provided | |
375 | * that there is a significant amount of free receive buffer space available. | |
376 | */ | |
377 | void x25_check_rbuf(struct sock *sk) | |
378 | { | |
379 | struct x25_sock *x25 = x25_sk(sk); | |
380 | ||
6bf1574e | 381 | if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) && |
1da177e4 LT |
382 | (x25->condition & X25_COND_OWN_RX_BUSY)) { |
383 | x25->condition &= ~X25_COND_OWN_RX_BUSY; | |
384 | x25->condition &= ~X25_COND_ACK_PENDING; | |
385 | x25->vl = x25->vr; | |
386 | x25_write_internal(sk, X25_RR); | |
387 | x25_stop_timer(sk); | |
388 | } | |
389 | } | |
390 |