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-rw-r--r--net/x25/x25_subr.c374
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diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c
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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 */
23
24#include <linux/kernel.h>
25#include <linux/string.h>
26#include <linux/skbuff.h>
27#include <net/sock.h>
28#include <net/tcp.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);
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 +
128 X25_MAX_CUD_LEN;
129 break;
130 case X25_CALL_ACCEPTED:
131 len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
132 break;
133 case X25_CLEAR_REQUEST:
134 case X25_RESET_REQUEST:
135 len += 2;
136 break;
137 case X25_RR:
138 case X25_RNR:
139 case X25_REJ:
140 case X25_CLEAR_CONFIRMATION:
141 case X25_INTERRUPT_CONFIRMATION:
142 case X25_RESET_CONFIRMATION:
143 break;
144 default:
145 printk(KERN_ERR "X.25: invalid frame type %02X\n",
146 frametype);
147 return;
148 }
149
150 if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
151 return;
152
153 /*
154 * Space for Ethernet and 802.2 LLC headers.
155 */
156 skb_reserve(skb, X25_MAX_L2_LEN);
157
158 /*
159 * Make space for the GFI and LCI, and fill them in.
160 */
161 dptr = skb_put(skb, 2);
162
163 lci1 = (x25->lci >> 8) & 0x0F;
164 lci2 = (x25->lci >> 0) & 0xFF;
165
166 if (x25->neighbour->extended) {
167 *dptr++ = lci1 | X25_GFI_EXTSEQ;
168 *dptr++ = lci2;
169 } else {
170 *dptr++ = lci1 | X25_GFI_STDSEQ;
171 *dptr++ = lci2;
172 }
173
174 /*
175 * Now fill in the frame type specific information.
176 */
177 switch (frametype) {
178
179 case X25_CALL_REQUEST:
180 dptr = skb_put(skb, 1);
181 *dptr++ = X25_CALL_REQUEST;
182 len = x25_addr_aton(addresses, &x25->dest_addr,
183 &x25->source_addr);
184 dptr = skb_put(skb, len);
185 memcpy(dptr, addresses, len);
186 len = x25_create_facilities(facilities,
187 &x25->facilities,
188 x25->neighbour->global_facil_mask);
189 dptr = skb_put(skb, len);
190 memcpy(dptr, facilities, len);
191 dptr = skb_put(skb, x25->calluserdata.cudlength);
192 memcpy(dptr, 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->vc_facil_mask);
204 dptr = skb_put(skb, len);
205 memcpy(dptr, facilities, len);
206 dptr = skb_put(skb, x25->calluserdata.cudlength);
207 memcpy(dptr, x25->calluserdata.cuddata,
208 x25->calluserdata.cudlength);
209 x25->calluserdata.cudlength = 0;
210 break;
211
212 case X25_CLEAR_REQUEST:
213 case X25_RESET_REQUEST:
214 dptr = skb_put(skb, 3);
215 *dptr++ = frametype;
216 *dptr++ = 0x00; /* XXX */
217 *dptr++ = 0x00; /* XXX */
218 break;
219
220 case X25_RR:
221 case X25_RNR:
222 case X25_REJ:
223 if (x25->neighbour->extended) {
224 dptr = skb_put(skb, 2);
225 *dptr++ = frametype;
226 *dptr++ = (x25->vr << 1) & 0xFE;
227 } else {
228 dptr = skb_put(skb, 1);
229 *dptr = frametype;
230 *dptr++ |= (x25->vr << 5) & 0xE0;
231 }
232 break;
233
234 case X25_CLEAR_CONFIRMATION:
235 case X25_INTERRUPT_CONFIRMATION:
236 case X25_RESET_CONFIRMATION:
237 dptr = skb_put(skb, 1);
238 *dptr = frametype;
239 break;
240 }
241
242 x25_transmit_link(skb, x25->neighbour);
243}
244
245/*
246 * Unpick the contents of the passed X.25 Packet Layer frame.
247 */
248int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
249 int *d, int *m)
250{
251 struct x25_sock *x25 = x25_sk(sk);
252 unsigned char *frame = skb->data;
253
254 *ns = *nr = *q = *d = *m = 0;
255
256 switch (frame[2]) {
257 case X25_CALL_REQUEST:
258 case X25_CALL_ACCEPTED:
259 case X25_CLEAR_REQUEST:
260 case X25_CLEAR_CONFIRMATION:
261 case X25_INTERRUPT:
262 case X25_INTERRUPT_CONFIRMATION:
263 case X25_RESET_REQUEST:
264 case X25_RESET_CONFIRMATION:
265 case X25_RESTART_REQUEST:
266 case X25_RESTART_CONFIRMATION:
267 case X25_REGISTRATION_REQUEST:
268 case X25_REGISTRATION_CONFIRMATION:
269 case X25_DIAGNOSTIC:
270 return frame[2];
271 }
272
273 if (x25->neighbour->extended) {
274 if (frame[2] == X25_RR ||
275 frame[2] == X25_RNR ||
276 frame[2] == X25_REJ) {
277 *nr = (frame[3] >> 1) & 0x7F;
278 return frame[2];
279 }
280 } else {
281 if ((frame[2] & 0x1F) == X25_RR ||
282 (frame[2] & 0x1F) == X25_RNR ||
283 (frame[2] & 0x1F) == X25_REJ) {
284 *nr = (frame[2] >> 5) & 0x07;
285 return frame[2] & 0x1F;
286 }
287 }
288
289 if (x25->neighbour->extended) {
290 if ((frame[2] & 0x01) == X25_DATA) {
291 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
292 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
293 *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
294 *nr = (frame[3] >> 1) & 0x7F;
295 *ns = (frame[2] >> 1) & 0x7F;
296 return X25_DATA;
297 }
298 } else {
299 if ((frame[2] & 0x01) == X25_DATA) {
300 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
301 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
302 *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
303 *nr = (frame[2] >> 5) & 0x07;
304 *ns = (frame[2] >> 1) & 0x07;
305 return X25_DATA;
306 }
307 }
308
309 printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n",
310 frame[0], frame[1], frame[2]);
311
312 return X25_ILLEGAL;
313}
314
315void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
316 unsigned char diagnostic)
317{
318 struct x25_sock *x25 = x25_sk(sk);
319
320 x25_clear_queues(sk);
321 x25_stop_timer(sk);
322
323 x25->lci = 0;
324 x25->state = X25_STATE_0;
325
326 x25->causediag.cause = cause;
327 x25->causediag.diagnostic = diagnostic;
328
329 sk->sk_state = TCP_CLOSE;
330 sk->sk_err = reason;
331 sk->sk_shutdown |= SEND_SHUTDOWN;
332
333 if (!sock_flag(sk, SOCK_DEAD)) {
334 sk->sk_state_change(sk);
335 sock_set_flag(sk, SOCK_DEAD);
336 }
337}
338
339/*
340 * Clear an own-rx-busy condition and tell the peer about this, provided
341 * that there is a significant amount of free receive buffer space available.
342 */
343void x25_check_rbuf(struct sock *sk)
344{
345 struct x25_sock *x25 = x25_sk(sk);
346
347 if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
348 (x25->condition & X25_COND_OWN_RX_BUSY)) {
349 x25->condition &= ~X25_COND_OWN_RX_BUSY;
350 x25->condition &= ~X25_COND_ACK_PENDING;
351 x25->vl = x25->vr;
352 x25_write_internal(sk, X25_RR);
353 x25_stop_timer(sk);
354 }
355}
356
357/*
358 * Compare 2 calluserdata structures, used to find correct listening sockets
359 * when call user data is used.
360 */
361int x25_check_calluserdata(struct x25_calluserdata *ours, struct x25_calluserdata *theirs)
362{
363 int i;
364 if (ours->cudlength != theirs->cudlength)
365 return 0;
366
367 for (i=0;i<ours->cudlength;i++) {
368 if (ours->cuddata[i] != theirs->cuddata[i]) {
369 return 0;
370 }
371 }
372 return 1;
373}
374
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-21 10:01:39 -0500