2 * X.25 Packet Layer release 002
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.
8 * This code REQUIRES 2.1.15 or higher
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.
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
21 * jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups
24 #include <linux/errno.h>
25 #include <linux/types.h>
26 #include <linux/socket.h>
28 #include <linux/kernel.h>
29 #include <linux/sched.h>
30 #include <linux/timer.h>
31 #include <linux/string.h>
32 #include <linux/sockios.h>
33 #include <linux/net.h>
34 #include <linux/inet.h>
35 #include <linux/netdevice.h>
36 #include <linux/skbuff.h>
39 #include <asm/system.h>
40 #include <linux/fcntl.h>
42 #include <linux/interrupt.h>
46 * This routine purges all of the queues of frames.
48 void x25_clear_queues(struct sock *sk)
50 struct x25_opt *x25 = x25_sk(sk);
52 skb_queue_purge(&sk->sk_write_queue);
53 skb_queue_purge(&x25->ack_queue);
54 skb_queue_purge(&x25->interrupt_in_queue);
55 skb_queue_purge(&x25->interrupt_out_queue);
56 skb_queue_purge(&x25->fragment_queue);
61 * This routine purges the input queue of those frames that have been
62 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
65 void x25_frames_acked(struct sock *sk, unsigned short nr)
68 struct x25_opt *x25 = x25_sk(sk);
69 int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
72 * Remove all the ack-ed frames from the ack queue.
75 while (skb_peek(&x25->ack_queue) && x25->va != nr) {
76 skb = skb_dequeue(&x25->ack_queue);
78 x25->va = (x25->va + 1) % modulus;
82 void x25_requeue_frames(struct sock *sk)
84 struct sk_buff *skb, *skb_prev = NULL;
87 * Requeue all the un-ack-ed frames on the output queue to be picked
88 * up by x25_kick. This arrangement handles the possibility of an empty
91 while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {
93 skb_queue_head(&sk->sk_write_queue, skb);
95 skb_append(skb_prev, skb);
101 * Validate that the value of nr is between va and vs. Return true or
104 int x25_validate_nr(struct sock *sk, unsigned short nr)
106 struct x25_opt *x25 = x25_sk(sk);
107 unsigned short vc = x25->va;
108 int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
110 while (vc != x25->vs) {
113 vc = (vc + 1) % modulus;
116 return nr == x25->vs ? 1 : 0;
120 * This routine is called when the packet layer internally generates a
123 void x25_write_internal(struct sock *sk, int frametype)
125 struct x25_opt *x25 = x25_sk(sk);
128 unsigned char facilities[X25_MAX_FAC_LEN];
129 unsigned char addresses[1 + X25_ADDR_LEN];
130 unsigned char lci1, lci2;
132 * Default safe frame size.
134 int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
140 case X25_CALL_REQUEST:
141 len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN +
144 case X25_CALL_ACCEPTED:
145 len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
147 case X25_CLEAR_REQUEST:
148 case X25_RESET_REQUEST:
154 case X25_CLEAR_CONFIRMATION:
155 case X25_INTERRUPT_CONFIRMATION:
156 case X25_RESET_CONFIRMATION:
159 printk(KERN_ERR "X.25: invalid frame type %02X\n",
164 if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
168 * Space for Ethernet and 802.2 LLC headers.
170 skb_reserve(skb, X25_MAX_L2_LEN);
173 * Make space for the GFI and LCI, and fill them in.
175 dptr = skb_put(skb, 2);
177 lci1 = (x25->lci >> 8) & 0x0F;
178 lci2 = (x25->lci >> 0) & 0xFF;
180 if (x25->neighbour->extended) {
181 *dptr++ = lci1 | X25_GFI_EXTSEQ;
184 *dptr++ = lci1 | X25_GFI_STDSEQ;
189 * Now fill in the frame type specific information.
193 case X25_CALL_REQUEST:
194 dptr = skb_put(skb, 1);
195 *dptr++ = X25_CALL_REQUEST;
196 len = x25_addr_aton(addresses, &x25->dest_addr,
198 dptr = skb_put(skb, len);
199 memcpy(dptr, addresses, len);
200 len = x25_create_facilities(facilities,
202 x25->neighbour->global_facil_mask);
203 dptr = skb_put(skb, len);
204 memcpy(dptr, facilities, len);
205 dptr = skb_put(skb, x25->calluserdata.cudlength);
206 memcpy(dptr, x25->calluserdata.cuddata,
207 x25->calluserdata.cudlength);
208 x25->calluserdata.cudlength = 0;
211 case X25_CALL_ACCEPTED:
212 dptr = skb_put(skb, 2);
213 *dptr++ = X25_CALL_ACCEPTED;
214 *dptr++ = 0x00; /* Address lengths */
215 len = x25_create_facilities(facilities,
218 dptr = skb_put(skb, len);
219 memcpy(dptr, facilities, len);
220 dptr = skb_put(skb, x25->calluserdata.cudlength);
221 memcpy(dptr, x25->calluserdata.cuddata,
222 x25->calluserdata.cudlength);
223 x25->calluserdata.cudlength = 0;
226 case X25_CLEAR_REQUEST:
227 case X25_RESET_REQUEST:
228 dptr = skb_put(skb, 3);
230 *dptr++ = 0x00; /* XXX */
231 *dptr++ = 0x00; /* XXX */
237 if (x25->neighbour->extended) {
238 dptr = skb_put(skb, 2);
240 *dptr++ = (x25->vr << 1) & 0xFE;
242 dptr = skb_put(skb, 1);
244 *dptr++ |= (x25->vr << 5) & 0xE0;
248 case X25_CLEAR_CONFIRMATION:
249 case X25_INTERRUPT_CONFIRMATION:
250 case X25_RESET_CONFIRMATION:
251 dptr = skb_put(skb, 1);
256 x25_transmit_link(skb, x25->neighbour);
260 * Unpick the contents of the passed X.25 Packet Layer frame.
262 int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
265 struct x25_opt *x25 = x25_sk(sk);
266 unsigned char *frame = skb->data;
268 *ns = *nr = *q = *d = *m = 0;
271 case X25_CALL_REQUEST:
272 case X25_CALL_ACCEPTED:
273 case X25_CLEAR_REQUEST:
274 case X25_CLEAR_CONFIRMATION:
276 case X25_INTERRUPT_CONFIRMATION:
277 case X25_RESET_REQUEST:
278 case X25_RESET_CONFIRMATION:
279 case X25_RESTART_REQUEST:
280 case X25_RESTART_CONFIRMATION:
281 case X25_REGISTRATION_REQUEST:
282 case X25_REGISTRATION_CONFIRMATION:
287 if (x25->neighbour->extended) {
288 if (frame[2] == X25_RR ||
289 frame[2] == X25_RNR ||
290 frame[2] == X25_REJ) {
291 *nr = (frame[3] >> 1) & 0x7F;
295 if ((frame[2] & 0x1F) == X25_RR ||
296 (frame[2] & 0x1F) == X25_RNR ||
297 (frame[2] & 0x1F) == X25_REJ) {
298 *nr = (frame[2] >> 5) & 0x07;
299 return frame[2] & 0x1F;
303 if (x25->neighbour->extended) {
304 if ((frame[2] & 0x01) == X25_DATA) {
305 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
306 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
307 *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
308 *nr = (frame[3] >> 1) & 0x7F;
309 *ns = (frame[2] >> 1) & 0x7F;
313 if ((frame[2] & 0x01) == X25_DATA) {
314 *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
315 *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
316 *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
317 *nr = (frame[2] >> 5) & 0x07;
318 *ns = (frame[2] >> 1) & 0x07;
323 printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n",
324 frame[0], frame[1], frame[2]);
329 void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
330 unsigned char diagnostic)
332 struct x25_opt *x25 = x25_sk(sk);
334 x25_clear_queues(sk);
338 x25->state = X25_STATE_0;
340 x25->causediag.cause = cause;
341 x25->causediag.diagnostic = diagnostic;
343 sk->sk_state = TCP_CLOSE;
345 sk->sk_shutdown |= SEND_SHUTDOWN;
347 if (!sock_flag(sk, SOCK_DEAD)) {
348 sk->sk_state_change(sk);
349 sock_set_flag(sk, SOCK_DEAD);
354 * Clear an own-rx-busy condition and tell the peer about this, provided
355 * that there is a significant amount of free receive buffer space available.
357 void x25_check_rbuf(struct sock *sk)
359 struct x25_opt *x25 = x25_sk(sk);
361 if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
362 (x25->condition & X25_COND_OWN_RX_BUSY)) {
363 x25->condition &= ~X25_COND_OWN_RX_BUSY;
364 x25->condition &= ~X25_COND_ACK_PENDING;
366 x25_write_internal(sk, X25_RR);