[linux.git] / net / x25 / x25_subr.c

/*
 *	X.25 Packet Layer release 002
 *
 *	This is ALPHA test software. This code may break your machine,
 *	randomly fail to work with new releases, misbehave and/or generally
 *	screw up. It might even work.
 *
 *	This code REQUIRES 2.1.15 or higher
 *
 *	This module:
 *		This module is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 *	History
 *	X.25 001	Jonathan Naylor	  Started coding.
 *	X.25 002	Jonathan Naylor	  Centralised disconnection processing.
 *	mar/20/00	Daniela Squassoni Disabling/enabling of facilities
 *					  negotiation.
 *	jun/24/01	Arnaldo C. Melo	  use skb_queue_purge, cleanups
 *	apr/04/15	Shaun Pereira		Fast select with no
 *						restriction on response.
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/x25.h>

/*
 *	This routine purges all of the queues of frames.
 */
void x25_clear_queues(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	skb_queue_purge(&sk->sk_write_queue);
	skb_queue_purge(&x25->ack_queue);
	skb_queue_purge(&x25->interrupt_in_queue);
	skb_queue_purge(&x25->interrupt_out_queue);
	skb_queue_purge(&x25->fragment_queue);
}


/*
 * This routine purges the input queue of those frames that have been
 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
 * SDL diagram.
*/
void x25_frames_acked(struct sock *sk, unsigned short nr)
{
	struct sk_buff *skb;
	struct x25_sock *x25 = x25_sk(sk);
	int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;

	/*
	 * Remove all the ack-ed frames from the ack queue.
	 */
	if (x25->va != nr)
		while (skb_peek(&x25->ack_queue) && x25->va != nr) {
			skb = skb_dequeue(&x25->ack_queue);
			kfree_skb(skb);
			x25->va = (x25->va + 1) % modulus;
		}
}

void x25_requeue_frames(struct sock *sk)
{
	struct sk_buff *skb, *skb_prev = NULL;

	/*
	 * Requeue all the un-ack-ed frames on the output queue to be picked
	 * up by x25_kick. This arrangement handles the possibility of an empty
	 * output queue.
	 */
	while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {
		if (!skb_prev)
			skb_queue_head(&sk->sk_write_queue, skb);
		else
			skb_append(skb_prev, skb, &sk->sk_write_queue);
		skb_prev = skb;
	}
}

/*
 *	Validate that the value of nr is between va and vs. Return true or
 *	false for testing.
 */
int x25_validate_nr(struct sock *sk, unsigned short nr)
{
	struct x25_sock *x25 = x25_sk(sk);
	unsigned short vc = x25->va;
	int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;

	while (vc != x25->vs) {
		if (nr == vc)
			return 1;
		vc = (vc + 1) % modulus;
	}

	return nr == x25->vs ? 1 : 0;
}

/*
 *  This routine is called when the packet layer internally generates a
 *  control frame.
 */
void x25_write_internal(struct sock *sk, int frametype)
{
	struct x25_sock *x25 = x25_sk(sk);
	struct sk_buff *skb;
	unsigned char  *dptr;
	unsigned char  facilities[X25_MAX_FAC_LEN];
	unsigned char  addresses[1 + X25_ADDR_LEN];
	unsigned char  lci1, lci2;
	/*
	 *	Default safe frame size.
	 */
	int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;

	/*
	 *	Adjust frame size.
	 */
	switch (frametype) {
	case X25_CALL_REQUEST:
		len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
		break;
	case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */
		if (x25->facilities.reverse & 0x80) {
			len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
		} else {
			len += 1 + X25_MAX_FAC_LEN;
		}
		break;
	case X25_CLEAR_REQUEST:
	case X25_RESET_REQUEST:
		len += 2;
		break;
	case X25_RR:
	case X25_RNR:
	case X25_REJ:
	case X25_CLEAR_CONFIRMATION:
	case X25_INTERRUPT_CONFIRMATION:
	case X25_RESET_CONFIRMATION:
		break;
	default:
		printk(KERN_ERR "X.25: invalid frame type %02X\n", frametype);
		return;
	}

	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
		return;

	/*
	 *	Space for Ethernet and 802.2 LLC headers.
	 */
	skb_reserve(skb, X25_MAX_L2_LEN);

	/*
	 *	Make space for the GFI and LCI, and fill them in.
	 */
	dptr = skb_put(skb, 2);

	lci1 = (x25->lci >> 8) & 0x0F;
	lci2 = (x25->lci >> 0) & 0xFF;

	if (x25->neighbour->extended) {
		*dptr++ = lci1 | X25_GFI_EXTSEQ;
		*dptr++ = lci2;
	} else {
		*dptr++ = lci1 | X25_GFI_STDSEQ;
		*dptr++ = lci2;
	}

	/*
	 *	Now fill in the frame type specific information.
	 */
	switch (frametype) {

		case X25_CALL_REQUEST:
			dptr    = skb_put(skb, 1);
			*dptr++ = X25_CALL_REQUEST;
			len     = x25_addr_aton(addresses, &x25->dest_addr,
						&x25->source_addr);
			dptr    = skb_put(skb, len);
			memcpy(dptr, addresses, len);
			len     = x25_create_facilities(facilities,
					&x25->facilities,
					&x25->dte_facilities,
					x25->neighbour->global_facil_mask);
			dptr    = skb_put(skb, len);
			memcpy(dptr, facilities, len);
			dptr = skb_put(skb, x25->calluserdata.cudlength);
			memcpy(dptr, x25->calluserdata.cuddata,
			       x25->calluserdata.cudlength);
			x25->calluserdata.cudlength = 0;
			break;

		case X25_CALL_ACCEPTED:
			dptr    = skb_put(skb, 2);
			*dptr++ = X25_CALL_ACCEPTED;
			*dptr++ = 0x00;		/* Address lengths */
			len     = x25_create_facilities(facilities,
							&x25->facilities,
							&x25->dte_facilities,
							x25->vc_facil_mask);
			dptr    = skb_put(skb, len);
			memcpy(dptr, facilities, len);

			/* fast select with no restriction on response
				allows call user data. Userland must
				ensure it is ours and not theirs */
			if(x25->facilities.reverse & 0x80) {
				dptr = skb_put(skb,
					x25->calluserdata.cudlength);
				memcpy(dptr, x25->calluserdata.cuddata,
				       x25->calluserdata.cudlength);
			}
			x25->calluserdata.cudlength = 0;
			break;

		case X25_CLEAR_REQUEST:
			dptr    = skb_put(skb, 3);
			*dptr++ = frametype;
			*dptr++ = x25->causediag.cause;
			*dptr++ = x25->causediag.diagnostic;
			break;

		case X25_RESET_REQUEST:
			dptr    = skb_put(skb, 3);
			*dptr++ = frametype;
			*dptr++ = 0x00;		/* XXX */
			*dptr++ = 0x00;		/* XXX */
			break;

		case X25_RR:
		case X25_RNR:
		case X25_REJ:
			if (x25->neighbour->extended) {
				dptr     = skb_put(skb, 2);
				*dptr++  = frametype;
				*dptr++  = (x25->vr << 1) & 0xFE;
			} else {
				dptr     = skb_put(skb, 1);
				*dptr    = frametype;
				*dptr++ |= (x25->vr << 5) & 0xE0;
			}
			break;

		case X25_CLEAR_CONFIRMATION:
		case X25_INTERRUPT_CONFIRMATION:
		case X25_RESET_CONFIRMATION:
			dptr  = skb_put(skb, 1);
			*dptr = frametype;
			break;
	}

	x25_transmit_link(skb, x25->neighbour);
}

/*
 *	Unpick the contents of the passed X.25 Packet Layer frame.
 */
int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
	       int *d, int *m)
{
	struct x25_sock *x25 = x25_sk(sk);
	unsigned char *frame;

	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
		return X25_ILLEGAL;
	frame = skb->data;

	*ns = *nr = *q = *d = *m = 0;

	switch (frame[2]) {
	case X25_CALL_REQUEST:
	case X25_CALL_ACCEPTED:
	case X25_CLEAR_REQUEST:
	case X25_CLEAR_CONFIRMATION:
	case X25_INTERRUPT:
	case X25_INTERRUPT_CONFIRMATION:
	case X25_RESET_REQUEST:
	case X25_RESET_CONFIRMATION:
	case X25_RESTART_REQUEST:
	case X25_RESTART_CONFIRMATION:
	case X25_REGISTRATION_REQUEST:
	case X25_REGISTRATION_CONFIRMATION:
	case X25_DIAGNOSTIC:
		return frame[2];
	}

	if (x25->neighbour->extended) {
		if (frame[2] == X25_RR  ||
		    frame[2] == X25_RNR ||
		    frame[2] == X25_REJ) {
			if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
				return X25_ILLEGAL;
			frame = skb->data;

			*nr = (frame[3] >> 1) & 0x7F;
			return frame[2];
		}
	} else {
		if ((frame[2] & 0x1F) == X25_RR  ||
		    (frame[2] & 0x1F) == X25_RNR ||
		    (frame[2] & 0x1F) == X25_REJ) {
			*nr = (frame[2] >> 5) & 0x07;
			return frame[2] & 0x1F;
		}
	}

	if (x25->neighbour->extended) {
		if ((frame[2] & 0x01) == X25_DATA) {
			if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
				return X25_ILLEGAL;
			frame = skb->data;

			*q  = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
			*d  = (frame[0] & X25_D_BIT) == X25_D_BIT;
			*m  = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
			*nr = (frame[3] >> 1) & 0x7F;
			*ns = (frame[2] >> 1) & 0x7F;
			return X25_DATA;
		}
	} else {
		if ((frame[2] & 0x01) == X25_DATA) {
			*q  = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
			*d  = (frame[0] & X25_D_BIT) == X25_D_BIT;
			*m  = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
			*nr = (frame[2] >> 5) & 0x07;
			*ns = (frame[2] >> 1) & 0x07;
			return X25_DATA;
		}
	}

	printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n",
	       frame[0], frame[1], frame[2]);

	return X25_ILLEGAL;
}

void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
		    unsigned char diagnostic)
{
	struct x25_sock *x25 = x25_sk(sk);

	x25_clear_queues(sk);
	x25_stop_timer(sk);

	x25->lci   = 0;
	x25->state = X25_STATE_0;

	x25->causediag.cause      = cause;
	x25->causediag.diagnostic = diagnostic;

	sk->sk_state     = TCP_CLOSE;
	sk->sk_err       = reason;
	sk->sk_shutdown |= SEND_SHUTDOWN;

	if (!sock_flag(sk, SOCK_DEAD)) {
		sk->sk_state_change(sk);
		sock_set_flag(sk, SOCK_DEAD);
	}
}

/*
 * Clear an own-rx-busy condition and tell the peer about this, provided
 * that there is a significant amount of free receive buffer space available.
 */
void x25_check_rbuf(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) &&
	    (x25->condition & X25_COND_OWN_RX_BUSY)) {
		x25->condition &= ~X25_COND_OWN_RX_BUSY;
		x25->condition &= ~X25_COND_ACK_PENDING;
		x25->vl         = x25->vr;
		x25_write_internal(sk, X25_RR);
		x25_stop_timer(sk);
	}
}
Commit	Line	Data
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
ebc3f64b SP	23	* restriction on response.
1da177e4 LT	24	*/
1da177e4 LT	25
5a0e3ad6	26	#include <linux/slab.h>
1da177e4 LT	27	#include <linux/kernel.h>
	28	#include <linux/string.h>
	29	#include <linux/skbuff.h>
	30	#include <net/sock.h>
c752f073	31	#include <net/tcp_states.h>
1da177e4 LT	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
8728b834	84	skb_append(skb_prev, skb, &sk->sk_write_queue);
1da177e4 LT	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) {
fddc5f3e JP	129	case X25_CALL_REQUEST:
	130	len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
	131	break;
	132	case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */
	133	if (x25->facilities.reverse & 0x80) {
	134	len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
	135	} else {
	136	len += 1 + X25_MAX_FAC_LEN;
	137	}
	138	break;
	139	case X25_CLEAR_REQUEST:
	140	case X25_RESET_REQUEST:
	141	len += 2;
	142	break;
	143	case X25_RR:
	144	case X25_RNR:
	145	case X25_REJ:
	146	case X25_CLEAR_CONFIRMATION:
	147	case X25_INTERRUPT_CONFIRMATION:
	148	case X25_RESET_CONFIRMATION:
	149	break;
	150	default:
	151	printk(KERN_ERR "X.25: invalid frame type %02X\n", frametype);
	152	return;
1da177e4 LT	153	}
	154
	155	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
	156	return;
	157
	158	/*
	159	* Space for Ethernet and 802.2 LLC headers.
	160	*/
	161	skb_reserve(skb, X25_MAX_L2_LEN);
	162
	163	/*
	164	* Make space for the GFI and LCI, and fill them in.
	165	*/
	166	dptr = skb_put(skb, 2);
	167
	168	lci1 = (x25->lci >> 8) & 0x0F;
	169	lci2 = (x25->lci >> 0) & 0xFF;
	170
	171	if (x25->neighbour->extended) {
	172	*dptr++ = lci1 \| X25_GFI_EXTSEQ;
	173	*dptr++ = lci2;
	174	} else {
	175	*dptr++ = lci1 \| X25_GFI_STDSEQ;
	176	*dptr++ = lci2;
	177	}
	178
	179	/*
	180	* Now fill in the frame type specific information.
	181	*/
	182	switch (frametype) {
	183
	184	case X25_CALL_REQUEST:
	185	dptr = skb_put(skb, 1);
	186	*dptr++ = X25_CALL_REQUEST;
	187	len = x25_addr_aton(addresses, &x25->dest_addr,
	188	&x25->source_addr);
	189	dptr = skb_put(skb, len);
	190	memcpy(dptr, addresses, len);
	191	len = x25_create_facilities(facilities,
a64b7b93 SP	192	&x25->facilities,
	193	&x25->dte_facilities,
	194	x25->neighbour->global_facil_mask);
1da177e4 LT	195	dptr = skb_put(skb, len);
	196	memcpy(dptr, facilities, len);
	197	dptr = skb_put(skb, x25->calluserdata.cudlength);
	198	memcpy(dptr, x25->calluserdata.cuddata,
	199	x25->calluserdata.cudlength);
	200	x25->calluserdata.cudlength = 0;
	201	break;
	202
	203	case X25_CALL_ACCEPTED:
	204	dptr = skb_put(skb, 2);
	205	*dptr++ = X25_CALL_ACCEPTED;
	206	dptr++ = 0x00; / Address lengths */
	207	len = x25_create_facilities(facilities,
	208	&x25->facilities,
a64b7b93	209	&x25->dte_facilities,
1da177e4 LT	210	x25->vc_facil_mask);
	211	dptr = skb_put(skb, len);
	212	memcpy(dptr, facilities, len);
ebc3f64b SP	213
	214	/* fast select with no restriction on response
	215	allows call user data. Userland must
	216	ensure it is ours and not theirs */
	217	if(x25->facilities.reverse & 0x80) {
	218	dptr = skb_put(skb,
	219	x25->calluserdata.cudlength);
	220	memcpy(dptr, x25->calluserdata.cuddata,
	221	x25->calluserdata.cudlength);
	222	}
1da177e4 LT	223	x25->calluserdata.cudlength = 0;
	224	break;
	225
	226	case X25_CLEAR_REQUEST:
386e50cc AH	227	dptr = skb_put(skb, 3);
	228	*dptr++ = frametype;
	229	*dptr++ = x25->causediag.cause;
	230	*dptr++ = x25->causediag.diagnostic;
	231	break;
	232
1da177e4 LT	233	case X25_RESET_REQUEST:
	234	dptr = skb_put(skb, 3);
	235	*dptr++ = frametype;
	236	dptr++ = 0x00; / XXX */
	237	dptr++ = 0x00; / XXX */
	238	break;
	239
	240	case X25_RR:
	241	case X25_RNR:
	242	case X25_REJ:
	243	if (x25->neighbour->extended) {
	244	dptr = skb_put(skb, 2);
	245	*dptr++ = frametype;
	246	*dptr++ = (x25->vr << 1) & 0xFE;
	247	} else {
	248	dptr = skb_put(skb, 1);
	249	*dptr = frametype;
	250	*dptr++ \|= (x25->vr << 5) & 0xE0;
	251	}
	252	break;
	253
	254	case X25_CLEAR_CONFIRMATION:
	255	case X25_INTERRUPT_CONFIRMATION:
	256	case X25_RESET_CONFIRMATION:
	257	dptr = skb_put(skb, 1);
	258	*dptr = frametype;
	259	break;
	260	}
	261
	262	x25_transmit_link(skb, x25->neighbour);
	263	}
	264
	265	/*
	266	* Unpick the contents of the passed X.25 Packet Layer frame.
	267	*/
	268	int x25_decode(struct sock sk, struct sk_buff skb, int ns, int nr, int *q,
	269	int d, int m)
	270	{
	271	struct x25_sock *x25 = x25_sk(sk);
cb101ed2 MD	272	unsigned char *frame;
	273
	274	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
	275	return X25_ILLEGAL;
	276	frame = skb->data;
1da177e4 LT	277
	278	ns = nr = q = d = *m = 0;
	279
	280	switch (frame[2]) {
fddc5f3e JP	281	case X25_CALL_REQUEST:
	282	case X25_CALL_ACCEPTED:
	283	case X25_CLEAR_REQUEST:
	284	case X25_CLEAR_CONFIRMATION:
	285	case X25_INTERRUPT:
	286	case X25_INTERRUPT_CONFIRMATION:
	287	case X25_RESET_REQUEST:
	288	case X25_RESET_CONFIRMATION:
	289	case X25_RESTART_REQUEST:
	290	case X25_RESTART_CONFIRMATION:
	291	case X25_REGISTRATION_REQUEST:
	292	case X25_REGISTRATION_CONFIRMATION:
	293	case X25_DIAGNOSTIC:
	294	return frame[2];
1da177e4 LT	295	}
	296
	297	if (x25->neighbour->extended) {
	298	if (frame[2] == X25_RR \|\|
	299	frame[2] == X25_RNR \|\|
	300	frame[2] == X25_REJ) {
cb101ed2 MD	301	if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
	302	return X25_ILLEGAL;
	303	frame = skb->data;
	304
1da177e4 LT	305	*nr = (frame[3] >> 1) & 0x7F;
	306	return frame[2];
	307	}
	308	} else {
	309	if ((frame[2] & 0x1F) == X25_RR \|\|
	310	(frame[2] & 0x1F) == X25_RNR \|\|
	311	(frame[2] & 0x1F) == X25_REJ) {
	312	*nr = (frame[2] >> 5) & 0x07;
	313	return frame[2] & 0x1F;
	314	}
	315	}
	316
	317	if (x25->neighbour->extended) {
	318	if ((frame[2] & 0x01) == X25_DATA) {
cb101ed2 MD	319	if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
	320	return X25_ILLEGAL;
	321	frame = skb->data;
	322
1da177e4 LT	323	*q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
	324	*d = (frame[0] & X25_D_BIT) == X25_D_BIT;
	325	*m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
	326	*nr = (frame[3] >> 1) & 0x7F;
	327	*ns = (frame[2] >> 1) & 0x7F;
	328	return X25_DATA;
	329	}
	330	} else {
	331	if ((frame[2] & 0x01) == X25_DATA) {
	332	*q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
	333	*d = (frame[0] & X25_D_BIT) == X25_D_BIT;
	334	*m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
	335	*nr = (frame[2] >> 5) & 0x07;
	336	*ns = (frame[2] >> 1) & 0x07;
	337	return X25_DATA;
	338	}
	339	}
	340
	341	printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n",
	342	frame[0], frame[1], frame[2]);
	343
	344	return X25_ILLEGAL;
	345	}
	346
	347	void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
	348	unsigned char diagnostic)
	349	{
	350	struct x25_sock *x25 = x25_sk(sk);
	351
	352	x25_clear_queues(sk);
	353	x25_stop_timer(sk);
	354
	355	x25->lci = 0;
	356	x25->state = X25_STATE_0;
	357
	358	x25->causediag.cause = cause;
	359	x25->causediag.diagnostic = diagnostic;
	360
	361	sk->sk_state = TCP_CLOSE;
	362	sk->sk_err = reason;
	363	sk->sk_shutdown \|= SEND_SHUTDOWN;
	364
	365	if (!sock_flag(sk, SOCK_DEAD)) {
	366	sk->sk_state_change(sk);
	367	sock_set_flag(sk, SOCK_DEAD);
	368	}
	369	}
	370
	371	/*
	372	* Clear an own-rx-busy condition and tell the peer about this, provided
	373	* that there is a significant amount of free receive buffer space available.
	374	*/
	375	void x25_check_rbuf(struct sock *sk)
	376	{
	377	struct x25_sock *x25 = x25_sk(sk);
	378
6bf1574e	379	if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) &&
1da177e4 LT	380	(x25->condition & X25_COND_OWN_RX_BUSY)) {
	381	x25->condition &= ~X25_COND_OWN_RX_BUSY;
	382	x25->condition &= ~X25_COND_ACK_PENDING;
	383	x25->vl = x25->vr;
	384	x25_write_internal(sk, X25_RR);
	385	x25_stop_timer(sk);
	386	}
	387	}
	388