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

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	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
 *
 *	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.
 */

#define pr_fmt(fmt) "X25: " fmt

#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:
		pr_err("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);
			skb_put_data(skb, addresses, len);
			len     = x25_create_facilities(facilities,
					&x25->facilities,
					&x25->dte_facilities,
					x25->neighbour->global_facil_mask);
			skb_put_data(skb, facilities, len);
			skb_put_data(skb, 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);
			skb_put_data(skb, 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) {
				skb_put_data(skb,
					     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;
		}
	}

	pr_debug("invalid PLP frame %3ph\n", frame);

	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);
	}
	if (x25->neighbour) {
		read_lock_bh(&x25_list_lock);
		x25_neigh_put(x25->neighbour);
		x25->neighbour = NULL;
		read_unlock_bh(&x25_list_lock);
	}
}

/*
 * 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
ee5d8f4d	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	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	*
1da177e4 LT	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
ebc3f64b SP	17	* apr/04/15 Shaun Pereira Fast select with no
ebc3f64b SP	18	* restriction on response.
1da177e4 LT	19	*/
1da177e4 LT	20
b73e9e3c	21	#define pr_fmt(fmt) "X25: " fmt
b73e9e3c	22
5a0e3ad6	23	#include <linux/slab.h>
1da177e4 LT	24	#include <linux/kernel.h>
	25	#include <linux/string.h>
	26	#include <linux/skbuff.h>
	27	#include <net/sock.h>
c752f073	28	#include <net/tcp_states.h>
1da177e4 LT	29	#include <net/x25.h>
	30
	31	/*
	32	* This routine purges all of the queues of frames.
	33	*/
	34	void 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	*/
	51	void 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
	68	void 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
8728b834	81	skb_append(skb_prev, skb, &sk->sk_write_queue);
1da177e4 LT	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	*/
	90	int 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	*/
	109	void 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) {
fddc5f3e JP	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:
b73e9e3c	148	pr_err("invalid frame type %02X\n", frametype);
fddc5f3e	149	return;
1da177e4 LT	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);
b952f4df	186	skb_put_data(skb, addresses, len);
1da177e4	187	len = x25_create_facilities(facilities,
a64b7b93 SP	188	&x25->facilities,
	189	&x25->dte_facilities,
	190	x25->neighbour->global_facil_mask);
b952f4df	191	skb_put_data(skb, facilities, len);
	192	skb_put_data(skb, x25->calluserdata.cuddata,
	193	x25->calluserdata.cudlength);
1da177e4 LT	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,
a64b7b93	203	&x25->dte_facilities,
1da177e4	204	x25->vc_facil_mask);
b952f4df	205	skb_put_data(skb, facilities, len);
ebc3f64b SP	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) {
b952f4df	211	skb_put_data(skb,
	212	x25->calluserdata.cuddata,
	213	x25->calluserdata.cudlength);
ebc3f64b	214	}
1da177e4 LT	215	x25->calluserdata.cudlength = 0;
	216	break;
	217
	218	case X25_CLEAR_REQUEST:
386e50cc AH	219	dptr = skb_put(skb, 3);
	220	*dptr++ = frametype;
	221	*dptr++ = x25->causediag.cause;
	222	*dptr++ = x25->causediag.diagnostic;
	223	break;
	224
1da177e4 LT	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	*/
	260	int 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);
cb101ed2 MD	264	unsigned char *frame;
	265
	266	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
	267	return X25_ILLEGAL;
	268	frame = skb->data;
1da177e4 LT	269
	270	ns = nr = q = d = *m = 0;
	271
	272	switch (frame[2]) {
fddc5f3e JP	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];
1da177e4 LT	287	}
	288
	289	if (x25->neighbour->extended) {
	290	if (frame[2] == X25_RR \|\|
	291	frame[2] == X25_RNR \|\|
	292	frame[2] == X25_REJ) {
cb101ed2 MD	293	if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
	294	return X25_ILLEGAL;
	295	frame = skb->data;
	296
1da177e4 LT	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) {
cb101ed2 MD	311	if (!pskb_may_pull(skb, X25_EXT_MIN_LEN))
	312	return X25_ILLEGAL;
	313	frame = skb->data;
	314
1da177e4 LT	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
3fef2b62	333	pr_debug("invalid PLP frame %3ph\n", frame);
1da177e4 LT	334
	335	return X25_ILLEGAL;
	336	}
	337
	338	void 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	}
8999dc89 Y	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	}
1da177e4 LT	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	*/
	372	void x25_check_rbuf(struct sock *sk)
	373	{
	374	struct x25_sock *x25 = x25_sk(sk);
	375
6bf1574e	376	if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf >> 1) &&
1da177e4 LT	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	}