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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 + |
131 | X25_MAX_CUD_LEN; |
132 | break; |
133 | case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */ |
134 | if(x25->facilities.reverse & 0x80) { |
135 | len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN; |
136 | } else { |
137 | len += 1 + X25_MAX_FAC_LEN; |
138 | } |
139 | break; |
140 | case X25_CLEAR_REQUEST: |
141 | case X25_RESET_REQUEST: |
142 | len += 2; |
143 | break; |
144 | case X25_RR: |
145 | case X25_RNR: |
146 | case X25_REJ: |
147 | case X25_CLEAR_CONFIRMATION: |
148 | case X25_INTERRUPT_CONFIRMATION: |
149 | case X25_RESET_CONFIRMATION: |
150 | break; |
151 | default: |
152 | printk(KERN_ERR "X.25: invalid frame type %02X\n", |
153 | frametype); |
154 | return; |
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, |
194 | &x25->facilities, |
195 | &x25->dte_facilities, |
196 | x25->neighbour->global_facil_mask); |
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, |
211 | &x25->dte_facilities, |
212 | x25->vc_facil_mask); |
213 | dptr = skb_put(skb, len); |
214 | memcpy(dptr, facilities, len); |
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 | } |
225 | x25->calluserdata.cudlength = 0; |
226 | break; |
227 | |
228 | case X25_CLEAR_REQUEST: |
229 | dptr = skb_put(skb, 3); |
230 | *dptr++ = frametype; |
231 | *dptr++ = x25->causediag.cause; |
232 | *dptr++ = x25->causediag.diagnostic; |
233 | break; |
234 | |
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); |
274 | unsigned char *frame = skb->data; |
275 | |
276 | *ns = *nr = *q = *d = *m = 0; |
277 | |
278 | switch (frame[2]) { |
279 | case X25_CALL_REQUEST: |
280 | case X25_CALL_ACCEPTED: |
281 | case X25_CLEAR_REQUEST: |
282 | case X25_CLEAR_CONFIRMATION: |
283 | case X25_INTERRUPT: |
284 | case X25_INTERRUPT_CONFIRMATION: |
285 | case X25_RESET_REQUEST: |
286 | case X25_RESET_CONFIRMATION: |
287 | case X25_RESTART_REQUEST: |
288 | case X25_RESTART_CONFIRMATION: |
289 | case X25_REGISTRATION_REQUEST: |
290 | case X25_REGISTRATION_CONFIRMATION: |
291 | case X25_DIAGNOSTIC: |
292 | return frame[2]; |
293 | } |
294 | |
295 | if (x25->neighbour->extended) { |
296 | if (frame[2] == X25_RR || |
297 | frame[2] == X25_RNR || |
298 | frame[2] == X25_REJ) { |
299 | *nr = (frame[3] >> 1) & 0x7F; |
300 | return frame[2]; |
301 | } |
302 | } else { |
303 | if ((frame[2] & 0x1F) == X25_RR || |
304 | (frame[2] & 0x1F) == X25_RNR || |
305 | (frame[2] & 0x1F) == X25_REJ) { |
306 | *nr = (frame[2] >> 5) & 0x07; |
307 | return frame[2] & 0x1F; |
308 | } |
309 | } |
310 | |
311 | if (x25->neighbour->extended) { |
312 | if ((frame[2] & 0x01) == X25_DATA) { |
313 | *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; |
314 | *d = (frame[0] & X25_D_BIT) == X25_D_BIT; |
315 | *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT; |
316 | *nr = (frame[3] >> 1) & 0x7F; |
317 | *ns = (frame[2] >> 1) & 0x7F; |
318 | return X25_DATA; |
319 | } |
320 | } else { |
321 | if ((frame[2] & 0x01) == X25_DATA) { |
322 | *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT; |
323 | *d = (frame[0] & X25_D_BIT) == X25_D_BIT; |
324 | *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT; |
325 | *nr = (frame[2] >> 5) & 0x07; |
326 | *ns = (frame[2] >> 1) & 0x07; |
327 | return X25_DATA; |
328 | } |
329 | } |
330 | |
331 | printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n", |
332 | frame[0], frame[1], frame[2]); |
333 | |
334 | return X25_ILLEGAL; |
335 | } |
336 | |
337 | void x25_disconnect(struct sock *sk, int reason, unsigned char cause, |
338 | unsigned char diagnostic) |
339 | { |
340 | struct x25_sock *x25 = x25_sk(sk); |
341 | |
342 | x25_clear_queues(sk); |
343 | x25_stop_timer(sk); |
344 | |
345 | x25->lci = 0; |
346 | x25->state = X25_STATE_0; |
347 | |
348 | x25->causediag.cause = cause; |
349 | x25->causediag.diagnostic = diagnostic; |
350 | |
351 | sk->sk_state = TCP_CLOSE; |
352 | sk->sk_err = reason; |
353 | sk->sk_shutdown |= SEND_SHUTDOWN; |
354 | |
355 | if (!sock_flag(sk, SOCK_DEAD)) { |
356 | sk->sk_state_change(sk); |
357 | sock_set_flag(sk, SOCK_DEAD); |
358 | } |
359 | } |
360 | |
361 | /* |
362 | * Clear an own-rx-busy condition and tell the peer about this, provided |
363 | * that there is a significant amount of free receive buffer space available. |
364 | */ |
365 | void x25_check_rbuf(struct sock *sk) |
366 | { |
367 | struct x25_sock *x25 = x25_sk(sk); |
368 | |
369 | if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) && |
370 | (x25->condition & X25_COND_OWN_RX_BUSY)) { |
371 | x25->condition &= ~X25_COND_OWN_RX_BUSY; |
372 | x25->condition &= ~X25_COND_ACK_PENDING; |
373 | x25->vl = x25->vr; |
374 | x25_write_internal(sk, X25_RR); |
375 | x25_stop_timer(sk); |
376 | } |
377 | } |
378 | |
379 |
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Tags:
od-2011-09-04
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v2.6.34-rc5
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