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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#define pr_fmt(fmt) "X25: " fmt
27
28#include <linux/slab.h>
29#include <linux/kernel.h>
30#include <linux/string.h>
31#include <linux/skbuff.h>
32#include <net/sock.h>
33#include <net/tcp_states.h>
34#include <net/x25.h>
35
36/*
37 * This routine purges all of the queues of frames.
38 */
39void 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*/
56void 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
73void 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
86 skb_append(skb_prev, skb, &sk->sk_write_queue);
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 */
95int 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 */
114void 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) {
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:
153 pr_err("invalid frame type %02X\n", 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 */
270int 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;
275
276 if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
277 return X25_ILLEGAL;
278 frame = skb->data;
279
280 *ns = *nr = *q = *d = *m = 0;
281
282 switch (frame[2]) {
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];
297 }
298
299 if (x25->neighbour->extended) {
300 if (frame[2] == X25_RR ||
301 frame[2] == X25_RNR ||
302 frame[2] == X25_REJ) {
303 if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
304 return X25_ILLEGAL;
305 frame = skb->data;
306
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) {
321 if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
322 return X25_ILLEGAL;
323 frame = skb->data;
324
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
343 pr_debug("invalid PLP frame %02X %02X %02X\n",
344 frame[0], frame[1], frame[2]);
345
346 return X25_ILLEGAL;
347}
348
349void 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 */
377void x25_check_rbuf(struct sock *sk)
378{
379 struct x25_sock *x25 = x25_sk(sk);
380
381 if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) &&
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
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * X.25 Packet Layer release 002
4 *
5 * This is ALPHA test software. This code may break your machine,
6 * randomly fail to work with new releases, misbehave and/or generally
7 * screw up. It might even work.
8 *
9 * This code REQUIRES 2.1.15 or higher
10 *
11 * History
12 * X.25 001 Jonathan Naylor Started coding.
13 * X.25 002 Jonathan Naylor Centralised disconnection processing.
14 * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
15 * negotiation.
16 * jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups
17 * apr/04/15 Shaun Pereira Fast select with no
18 * restriction on response.
19 */
20
21#define pr_fmt(fmt) "X25: " fmt
22
23#include <linux/slab.h>
24#include <linux/kernel.h>
25#include <linux/string.h>
26#include <linux/skbuff.h>
27#include <net/sock.h>
28#include <net/tcp_states.h>
29#include <net/x25.h>
30
31/*
32 * This routine purges all of the queues of frames.
33 */
34void x25_clear_queues(struct sock *sk)
35{
36 struct x25_sock *x25 = x25_sk(sk);
37
38 skb_queue_purge(&sk->sk_write_queue);
39 skb_queue_purge(&x25->ack_queue);
40 skb_queue_purge(&x25->interrupt_in_queue);
41 skb_queue_purge(&x25->interrupt_out_queue);
42 skb_queue_purge(&x25->fragment_queue);
43}
44
45
46/*
47 * This routine purges the input queue of those frames that have been
48 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
49 * SDL diagram.
50*/
51void x25_frames_acked(struct sock *sk, unsigned short nr)
52{
53 struct sk_buff *skb;
54 struct x25_sock *x25 = x25_sk(sk);
55 int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
56
57 /*
58 * Remove all the ack-ed frames from the ack queue.
59 */
60 if (x25->va != nr)
61 while (skb_peek(&x25->ack_queue) && x25->va != nr) {
62 skb = skb_dequeue(&x25->ack_queue);
63 kfree_skb(skb);
64 x25->va = (x25->va + 1) % modulus;
65 }
66}
67
68void x25_requeue_frames(struct sock *sk)
69{
70 struct sk_buff *skb, *skb_prev = NULL;
71
72 /*
73 * Requeue all the un-ack-ed frames on the output queue to be picked
74 * up by x25_kick. This arrangement handles the possibility of an empty
75 * output queue.
76 */
77 while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {
78 if (!skb_prev)
79 skb_queue_head(&sk->sk_write_queue, skb);
80 else
81 skb_append(skb_prev, skb, &sk->sk_write_queue);
82 skb_prev = skb;
83 }
84}
85
86/*
87 * Validate that the value of nr is between va and vs. Return true or
88 * false for testing.
89 */
90int x25_validate_nr(struct sock *sk, unsigned short nr)
91{
92 struct x25_sock *x25 = x25_sk(sk);
93 unsigned short vc = x25->va;
94 int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
95
96 while (vc != x25->vs) {
97 if (nr == vc)
98 return 1;
99 vc = (vc + 1) % modulus;
100 }
101
102 return nr == x25->vs ? 1 : 0;
103}
104
105/*
106 * This routine is called when the packet layer internally generates a
107 * control frame.
108 */
109void x25_write_internal(struct sock *sk, int frametype)
110{
111 struct x25_sock *x25 = x25_sk(sk);
112 struct sk_buff *skb;
113 unsigned char *dptr;
114 unsigned char facilities[X25_MAX_FAC_LEN];
115 unsigned char addresses[1 + X25_ADDR_LEN];
116 unsigned char lci1, lci2;
117 /*
118 * Default safe frame size.
119 */
120 int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
121
122 /*
123 * Adjust frame size.
124 */
125 switch (frametype) {
126 case X25_CALL_REQUEST:
127 len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
128 break;
129 case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */
130 if (x25->facilities.reverse & 0x80) {
131 len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
132 } else {
133 len += 1 + X25_MAX_FAC_LEN;
134 }
135 break;
136 case X25_CLEAR_REQUEST:
137 case X25_RESET_REQUEST:
138 len += 2;
139 break;
140 case X25_RR:
141 case X25_RNR:
142 case X25_REJ:
143 case X25_CLEAR_CONFIRMATION:
144 case X25_INTERRUPT_CONFIRMATION:
145 case X25_RESET_CONFIRMATION:
146 break;
147 default:
148 pr_err("invalid frame type %02X\n", frametype);
149 return;
150 }
151
152 if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
153 return;
154
155 /*
156 * Space for Ethernet and 802.2 LLC headers.
157 */
158 skb_reserve(skb, X25_MAX_L2_LEN);
159
160 /*
161 * Make space for the GFI and LCI, and fill them in.
162 */
163 dptr = skb_put(skb, 2);
164
165 lci1 = (x25->lci >> 8) & 0x0F;
166 lci2 = (x25->lci >> 0) & 0xFF;
167
168 if (x25->neighbour->extended) {
169 *dptr++ = lci1 | X25_GFI_EXTSEQ;
170 *dptr++ = lci2;
171 } else {
172 *dptr++ = lci1 | X25_GFI_STDSEQ;
173 *dptr++ = lci2;
174 }
175
176 /*
177 * Now fill in the frame type specific information.
178 */
179 switch (frametype) {
180
181 case X25_CALL_REQUEST:
182 dptr = skb_put(skb, 1);
183 *dptr++ = X25_CALL_REQUEST;
184 len = x25_addr_aton(addresses, &x25->dest_addr,
185 &x25->source_addr);
186 skb_put_data(skb, addresses, len);
187 len = x25_create_facilities(facilities,
188 &x25->facilities,
189 &x25->dte_facilities,
190 x25->neighbour->global_facil_mask);
191 skb_put_data(skb, facilities, len);
192 skb_put_data(skb, x25->calluserdata.cuddata,
193 x25->calluserdata.cudlength);
194 x25->calluserdata.cudlength = 0;
195 break;
196
197 case X25_CALL_ACCEPTED:
198 dptr = skb_put(skb, 2);
199 *dptr++ = X25_CALL_ACCEPTED;
200 *dptr++ = 0x00; /* Address lengths */
201 len = x25_create_facilities(facilities,
202 &x25->facilities,
203 &x25->dte_facilities,
204 x25->vc_facil_mask);
205 skb_put_data(skb, facilities, len);
206
207 /* fast select with no restriction on response
208 allows call user data. Userland must
209 ensure it is ours and not theirs */
210 if(x25->facilities.reverse & 0x80) {
211 skb_put_data(skb,
212 x25->calluserdata.cuddata,
213 x25->calluserdata.cudlength);
214 }
215 x25->calluserdata.cudlength = 0;
216 break;
217
218 case X25_CLEAR_REQUEST:
219 dptr = skb_put(skb, 3);
220 *dptr++ = frametype;
221 *dptr++ = x25->causediag.cause;
222 *dptr++ = x25->causediag.diagnostic;
223 break;
224
225 case X25_RESET_REQUEST:
226 dptr = skb_put(skb, 3);
227 *dptr++ = frametype;
228 *dptr++ = 0x00; /* XXX */
229 *dptr++ = 0x00; /* XXX */
230 break;
231
232 case X25_RR:
233 case X25_RNR:
234 case X25_REJ:
235 if (x25->neighbour->extended) {
236 dptr = skb_put(skb, 2);
237 *dptr++ = frametype;
238 *dptr++ = (x25->vr << 1) & 0xFE;
239 } else {
240 dptr = skb_put(skb, 1);
241 *dptr = frametype;
242 *dptr++ |= (x25->vr << 5) & 0xE0;
243 }
244 break;
245
246 case X25_CLEAR_CONFIRMATION:
247 case X25_INTERRUPT_CONFIRMATION:
248 case X25_RESET_CONFIRMATION:
249 dptr = skb_put(skb, 1);
250 *dptr = frametype;
251 break;
252 }
253
254 x25_transmit_link(skb, x25->neighbour);
255}
256
257/*
258 * Unpick the contents of the passed X.25 Packet Layer frame.
259 */
260int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
261 int *d, int *m)
262{
263 struct x25_sock *x25 = x25_sk(sk);
264 unsigned char *frame;
265
266 if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
267 return X25_ILLEGAL;
268 frame = skb->data;
269
270 *ns = *nr = *q = *d = *m = 0;
271
272 switch (frame[2]) {
273 case X25_CALL_REQUEST:
274 case X25_CALL_ACCEPTED:
275 case X25_CLEAR_REQUEST:
276 case X25_CLEAR_CONFIRMATION:
277 case X25_INTERRUPT:
278 case X25_INTERRUPT_CONFIRMATION:
279 case X25_RESET_REQUEST:
280 case X25_RESET_CONFIRMATION:
281 case X25_RESTART_REQUEST:
282 case X25_RESTART_CONFIRMATION:
283 case X25_REGISTRATION_REQUEST:
284 case X25_REGISTRATION_CONFIRMATION:
285 case X25_DIAGNOSTIC:
286 return frame[2];
287 }
288
289 if (x25->neighbour->extended) {
290 if (frame[2] == X25_RR ||
291 frame[2] == X25_RNR ||
292 frame[2] == X25_REJ) {
293 if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
294 return X25_ILLEGAL;
295 frame = skb->data;
296
297 *nr = (frame[3] >> 1) & 0x7F;
298 return frame[2];
299 }
300 } else {
301 if ((frame[2] & 0x1F) == X25_RR ||
302 (frame[2] & 0x1F) == X25_RNR ||
303 (frame[2] & 0x1F) == X25_REJ) {
304 *nr = (frame[2] >> 5) & 0x07;
305 return frame[2] & 0x1F;
306 }
307 }
308
309 if (x25->neighbour->extended) {
310 if ((frame[2] & 0x01) == X25_DATA) {
311 if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
312 return X25_ILLEGAL;
313 frame = skb->data;
314
315 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
316 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
317 *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
318 *nr = (frame[3] >> 1) & 0x7F;
319 *ns = (frame[2] >> 1) & 0x7F;
320 return X25_DATA;
321 }
322 } else {
323 if ((frame[2] & 0x01) == X25_DATA) {
324 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
325 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
326 *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
327 *nr = (frame[2] >> 5) & 0x07;
328 *ns = (frame[2] >> 1) & 0x07;
329 return X25_DATA;
330 }
331 }
332
333 pr_debug("invalid PLP frame %3ph\n", frame);
334
335 return X25_ILLEGAL;
336}
337
338void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
339 unsigned char diagnostic)
340{
341 struct x25_sock *x25 = x25_sk(sk);
342
343 x25_clear_queues(sk);
344 x25_stop_timer(sk);
345
346 x25->lci = 0;
347 x25->state = X25_STATE_0;
348
349 x25->causediag.cause = cause;
350 x25->causediag.diagnostic = diagnostic;
351
352 sk->sk_state = TCP_CLOSE;
353 sk->sk_err = reason;
354 sk->sk_shutdown |= SEND_SHUTDOWN;
355
356 if (!sock_flag(sk, SOCK_DEAD)) {
357 sk->sk_state_change(sk);
358 sock_set_flag(sk, SOCK_DEAD);
359 }
360 if (x25->neighbour) {
361 read_lock_bh(&x25_list_lock);
362 x25_neigh_put(x25->neighbour);
363 x25->neighbour = NULL;
364 read_unlock_bh(&x25_list_lock);
365 }
366}
367
368/*
369 * Clear an own-rx-busy condition and tell the peer about this, provided
370 * that there is a significant amount of free receive buffer space available.
371 */
372void x25_check_rbuf(struct sock *sk)
373{
374 struct x25_sock *x25 = x25_sk(sk);
375
376 if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) &&
377 (x25->condition & X25_COND_OWN_RX_BUSY)) {
378 x25->condition &= ~X25_COND_OWN_RX_BUSY;
379 x25->condition &= ~X25_COND_ACK_PENDING;
380 x25->vl = x25->vr;
381 x25_write_internal(sk, X25_RR);
382 x25_stop_timer(sk);
383 }
384}