[linux.git] / net / x25 / x25_in.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 code.
 *					  New timer architecture.
 *	2000-03-20	Daniela Squassoni Disabling/enabling of facilities
 *					  negotiation.
 *	2000-11-10	Henner Eisen	  Check and reset for out-of-sequence
 *					  i-frames.
 */

#define pr_fmt(fmt) "X25: " fmt

#include <linux/slab.h>
#include <linux/errno.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>

static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
{
	struct sk_buff *skbo, *skbn = skb;
	struct x25_sock *x25 = x25_sk(sk);

	if (more) {
		x25->fraglen += skb->len;
		skb_queue_tail(&x25->fragment_queue, skb);
		skb_set_owner_r(skb, sk);
		return 0;
	}

	if (!more && x25->fraglen > 0) {	/* End of fragment */
		int len = x25->fraglen + skb->len;

		if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
			kfree_skb(skb);
			return 1;
		}

		skb_queue_tail(&x25->fragment_queue, skb);

		skb_reset_transport_header(skbn);

		skbo = skb_dequeue(&x25->fragment_queue);
		skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
					  skbo->len);
		kfree_skb(skbo);

		while ((skbo =
			skb_dequeue(&x25->fragment_queue)) != NULL) {
			skb_pull(skbo, (x25->neighbour->extended) ?
					X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
			skb_copy_from_linear_data(skbo,
						  skb_put(skbn, skbo->len),
						  skbo->len);
			kfree_skb(skbo);
		}

		x25->fraglen = 0;
	}

	skb_set_owner_r(skbn, sk);
	skb_queue_tail(&sk->sk_receive_queue, skbn);
	if (!sock_flag(sk, SOCK_DEAD))
		sk->sk_data_ready(sk);

	return 0;
}

/*
 * State machine for state 1, Awaiting Call Accepted State.
 * The handling of the timer(s) is in file x25_timer.c.
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	struct x25_address source_addr, dest_addr;
	int len;
	struct x25_sock *x25 = x25_sk(sk);

	switch (frametype) {
	case X25_CALL_ACCEPTED: {

		x25_stop_timer(sk);
		x25->condition = 0x00;
		x25->vs        = 0;
		x25->va        = 0;
		x25->vr        = 0;
		x25->vl        = 0;
		x25->state     = X25_STATE_3;
		sk->sk_state   = TCP_ESTABLISHED;
		/*
		 *	Parse the data in the frame.
		 */
		if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
			goto out_clear;
		skb_pull(skb, X25_STD_MIN_LEN);

		len = x25_parse_address_block(skb, &source_addr,
					      &dest_addr);
		if (len > 0)
			skb_pull(skb, len);
		else if (len < 0)
			goto out_clear;

		len = x25_parse_facilities(skb, &x25->facilities,
					   &x25->dte_facilities,
					   &x25->vc_facil_mask);
		if (len > 0)
			skb_pull(skb, len);
		else if (len < 0)
			goto out_clear;
		/*
		 *	Copy any Call User Data.
		 */
		if (skb->len > 0) {
			if (skb->len > X25_MAX_CUD_LEN)
				goto out_clear;

			skb_copy_bits(skb, 0, x25->calluserdata.cuddata,
				skb->len);
			x25->calluserdata.cudlength = skb->len;
		}
		if (!sock_flag(sk, SOCK_DEAD))
			sk->sk_state_change(sk);
		break;
	}
	case X25_CLEAR_REQUEST:
		if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
			goto out_clear;

		x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
		x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
		break;

	default:
		break;
	}

	return 0;

out_clear:
	x25_write_internal(sk, X25_CLEAR_REQUEST);
	x25->state = X25_STATE_2;
	x25_start_t23timer(sk);
	return 0;
}

/*
 * State machine for state 2, Awaiting Clear Confirmation State.
 * The handling of the timer(s) is in file x25_timer.c
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	switch (frametype) {

		case X25_CLEAR_REQUEST:
			if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
				goto out_clear;

			x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
			x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
			break;

		case X25_CLEAR_CONFIRMATION:
			x25_disconnect(sk, 0, 0, 0);
			break;

		default:
			break;
	}

	return 0;

out_clear:
	x25_write_internal(sk, X25_CLEAR_REQUEST);
	x25_start_t23timer(sk);
	return 0;
}

/*
 * State machine for state 3, Connected State.
 * The handling of the timer(s) is in file x25_timer.c
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
{
	int queued = 0;
	int modulus;
	struct x25_sock *x25 = x25_sk(sk);

	modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;

	switch (frametype) {

		case X25_RESET_REQUEST:
			x25_write_internal(sk, X25_RESET_CONFIRMATION);
			x25_stop_timer(sk);
			x25->condition = 0x00;
			x25->vs        = 0;
			x25->vr        = 0;
			x25->va        = 0;
			x25->vl        = 0;
			x25_requeue_frames(sk);
			break;

		case X25_CLEAR_REQUEST:
			if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
				goto out_clear;

			x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
			x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
			break;

		case X25_RR:
		case X25_RNR:
			if (!x25_validate_nr(sk, nr)) {
				x25_clear_queues(sk);
				x25_write_internal(sk, X25_RESET_REQUEST);
				x25_start_t22timer(sk);
				x25->condition = 0x00;
				x25->vs        = 0;
				x25->vr        = 0;
				x25->va        = 0;
				x25->vl        = 0;
				x25->state     = X25_STATE_4;
			} else {
				x25_frames_acked(sk, nr);
				if (frametype == X25_RNR) {
					x25->condition |= X25_COND_PEER_RX_BUSY;
				} else {
					x25->condition &= ~X25_COND_PEER_RX_BUSY;
				}
			}
			break;

		case X25_DATA:	/* XXX */
			x25->condition &= ~X25_COND_PEER_RX_BUSY;
			if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
				x25_clear_queues(sk);
				x25_write_internal(sk, X25_RESET_REQUEST);
				x25_start_t22timer(sk);
				x25->condition = 0x00;
				x25->vs        = 0;
				x25->vr        = 0;
				x25->va        = 0;
				x25->vl        = 0;
				x25->state     = X25_STATE_4;
				break;
			}
			x25_frames_acked(sk, nr);
			if (ns == x25->vr) {
				if (x25_queue_rx_frame(sk, skb, m) == 0) {
					x25->vr = (x25->vr + 1) % modulus;
					queued = 1;
				} else {
					/* Should never happen */
					x25_clear_queues(sk);
					x25_write_internal(sk, X25_RESET_REQUEST);
					x25_start_t22timer(sk);
					x25->condition = 0x00;
					x25->vs        = 0;
					x25->vr        = 0;
					x25->va        = 0;
					x25->vl        = 0;
					x25->state     = X25_STATE_4;
					break;
				}
				if (atomic_read(&sk->sk_rmem_alloc) >
				    (sk->sk_rcvbuf >> 1))
					x25->condition |= X25_COND_OWN_RX_BUSY;
			}
			/*
			 *	If the window is full Ack it immediately, else
			 *	start the holdback timer.
			 */
			if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
				x25->condition &= ~X25_COND_ACK_PENDING;
				x25_stop_timer(sk);
				x25_enquiry_response(sk);
			} else {
				x25->condition |= X25_COND_ACK_PENDING;
				x25_start_t2timer(sk);
			}
			break;

		case X25_INTERRUPT_CONFIRMATION:
			clear_bit(X25_INTERRUPT_FLAG, &x25->flags);
			break;

		case X25_INTERRUPT:
			if (sock_flag(sk, SOCK_URGINLINE))
				queued = !sock_queue_rcv_skb(sk, skb);
			else {
				skb_set_owner_r(skb, sk);
				skb_queue_tail(&x25->interrupt_in_queue, skb);
				queued = 1;
			}
			sk_send_sigurg(sk);
			x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
			break;

		default:
			pr_warn("unknown %02X in state 3\n", frametype);
			break;
	}

	return queued;

out_clear:
	x25_write_internal(sk, X25_CLEAR_REQUEST);
	x25->state = X25_STATE_2;
	x25_start_t23timer(sk);
	return 0;
}

/*
 * State machine for state 4, Awaiting Reset Confirmation State.
 * The handling of the timer(s) is in file x25_timer.c
 * Handling of state 0 and connection release is in af_x25.c.
 */
static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
	struct x25_sock *x25 = x25_sk(sk);

	switch (frametype) {

		case X25_RESET_REQUEST:
			x25_write_internal(sk, X25_RESET_CONFIRMATION);
		case X25_RESET_CONFIRMATION: {
			x25_stop_timer(sk);
			x25->condition = 0x00;
			x25->va        = 0;
			x25->vr        = 0;
			x25->vs        = 0;
			x25->vl        = 0;
			x25->state     = X25_STATE_3;
			x25_requeue_frames(sk);
			break;
		}
		case X25_CLEAR_REQUEST:
			if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
				goto out_clear;

			x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
			x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
			break;

		default:
			break;
	}

	return 0;

out_clear:
	x25_write_internal(sk, X25_CLEAR_REQUEST);
	x25->state = X25_STATE_2;
	x25_start_t23timer(sk);
	return 0;
}

/* Higher level upcall for a LAPB frame */
int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
{
	struct x25_sock *x25 = x25_sk(sk);
	int queued = 0, frametype, ns, nr, q, d, m;

	if (x25->state == X25_STATE_0)
		return 0;

	frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);

	switch (x25->state) {
	case X25_STATE_1:
		queued = x25_state1_machine(sk, skb, frametype);
		break;
	case X25_STATE_2:
		queued = x25_state2_machine(sk, skb, frametype);
		break;
	case X25_STATE_3:
		queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
		break;
	case X25_STATE_4:
		queued = x25_state4_machine(sk, skb, frametype);
		break;
	}

	x25_kick(sk);

	return queued;
}

int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
	int queued = x25_process_rx_frame(sk, skb);

	if (!queued)
		kfree_skb(skb);

	return 0;
}
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
f8e1d201	6	* screw up. It might even work.
1da177e4 LT	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 code.
	19	* New timer architecture.
f8e1d201	20	* 2000-03-20 Daniela Squassoni Disabling/enabling of facilities
1da177e4 LT	21	* negotiation.
	22	* 2000-11-10 Henner Eisen Check and reset for out-of-sequence
	23	* i-frames.
	24	*/
	25
b73e9e3c	26	#define pr_fmt(fmt) "X25: " fmt
b73e9e3c	27
5a0e3ad6	28	#include <linux/slab.h>
1da177e4 LT	29	#include <linux/errno.h>
	30	#include <linux/kernel.h>
	31	#include <linux/string.h>
	32	#include <linux/skbuff.h>
	33	#include <net/sock.h>
c752f073	34	#include <net/tcp_states.h>
1da177e4 LT	35	#include <net/x25.h>
	36
	37	static int x25_queue_rx_frame(struct sock sk, struct sk_buff skb, int more)
	38	{
	39	struct sk_buff skbo, skbn = skb;
	40	struct x25_sock *x25 = x25_sk(sk);
	41
	42	if (more) {
	43	x25->fraglen += skb->len;
	44	skb_queue_tail(&x25->fragment_queue, skb);
	45	skb_set_owner_r(skb, sk);
	46	return 0;
	47	}
	48
	49	if (!more && x25->fraglen > 0) { /* End of fragment */
	50	int len = x25->fraglen + skb->len;
	51
	52	if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
	53	kfree_skb(skb);
	54	return 1;
	55	}
	56
	57	skb_queue_tail(&x25->fragment_queue, skb);
	58
badff6d0	59	skb_reset_transport_header(skbn);
1da177e4 LT	60
1da177e4 LT	61	skbo = skb_dequeue(&x25->fragment_queue);
1a4e2d09 ACM	62	skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
1a4e2d09 ACM	63	skbo->len);
1da177e4 LT	64	kfree_skb(skbo);
	65
	66	while ((skbo =
	67	skb_dequeue(&x25->fragment_queue)) != NULL) {
	68	skb_pull(skbo, (x25->neighbour->extended) ?
	69	X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
1a4e2d09 ACM	70	skb_copy_from_linear_data(skbo,
	71	skb_put(skbn, skbo->len),
	72	skbo->len);
1da177e4 LT	73	kfree_skb(skbo);
	74	}
	75
f8e1d201	76	x25->fraglen = 0;
1da177e4 LT	77	}
	78
	79	skb_set_owner_r(skbn, sk);
	80	skb_queue_tail(&sk->sk_receive_queue, skbn);
	81	if (!sock_flag(sk, SOCK_DEAD))
676d2369	82	sk->sk_data_ready(sk);
1da177e4 LT	83
	84	return 0;
	85	}
	86
	87	/*
	88	* State machine for state 1, Awaiting Call Accepted State.
	89	* The handling of the timer(s) is in file x25_timer.c.
	90	* Handling of state 0 and connection release is in af_x25.c.
	91	*/
	92	static int x25_state1_machine(struct sock sk, struct sk_buff skb, int frametype)
	93	{
	94	struct x25_address source_addr, dest_addr;
f5eb917b	95	int len;
95c30430	96	struct x25_sock *x25 = x25_sk(sk);
1da177e4 LT	97
1da177e4 LT	98	switch (frametype) {
fddc5f3e JP	99	case X25_CALL_ACCEPTED: {
	100
	101	x25_stop_timer(sk);
	102	x25->condition = 0x00;
	103	x25->vs = 0;
	104	x25->va = 0;
	105	x25->vr = 0;
	106	x25->vl = 0;
	107	x25->state = X25_STATE_3;
	108	sk->sk_state = TCP_ESTABLISHED;
	109	/*
	110	* Parse the data in the frame.
	111	*/
cb101ed2 MD	112	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
cb101ed2 MD	113	goto out_clear;
fddc5f3e JP	114	skb_pull(skb, X25_STD_MIN_LEN);
	115
	116	len = x25_parse_address_block(skb, &source_addr,
	117	&dest_addr);
	118	if (len > 0)
	119	skb_pull(skb, len);
	120	else if (len < 0)
	121	goto out_clear;
	122
	123	len = x25_parse_facilities(skb, &x25->facilities,
	124	&x25->dte_facilities,
	125	&x25->vc_facil_mask);
	126	if (len > 0)
	127	skb_pull(skb, len);
	128	else if (len < 0)
	129	goto out_clear;
	130	/*
	131	* Copy any Call User Data.
	132	*/
	133	if (skb->len > 0) {
c7fd0d48 MD	134	if (skb->len > X25_MAX_CUD_LEN)
	135	goto out_clear;
	136
cb101ed2 MD	137	skb_copy_bits(skb, 0, x25->calluserdata.cuddata,
cb101ed2 MD	138	skb->len);
fddc5f3e	139	x25->calluserdata.cudlength = skb->len;
1da177e4	140	}
fddc5f3e JP	141	if (!sock_flag(sk, SOCK_DEAD))
	142	sk->sk_state_change(sk);
	143	break;
	144	}
	145	case X25_CLEAR_REQUEST:
cb101ed2 MD	146	if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
	147	goto out_clear;
	148
fddc5f3e JP	149	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	150	x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
	151	break;
1da177e4	152
fddc5f3e JP	153	default:
fddc5f3e JP	154	break;
1da177e4 LT	155	}
	156
	157	return 0;
95c30430	158
	159	out_clear:
	160	x25_write_internal(sk, X25_CLEAR_REQUEST);
	161	x25->state = X25_STATE_2;
	162	x25_start_t23timer(sk);
	163	return 0;
1da177e4 LT	164	}
	165
	166	/*
	167	* State machine for state 2, Awaiting Clear Confirmation State.
	168	* The handling of the timer(s) is in file x25_timer.c
	169	* Handling of state 0 and connection release is in af_x25.c.
	170	*/
	171	static int x25_state2_machine(struct sock sk, struct sk_buff skb, int frametype)
	172	{
	173	switch (frametype) {
	174
	175	case X25_CLEAR_REQUEST:
cb101ed2 MD	176	if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
	177	goto out_clear;
	178
1da177e4 LT	179	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	180	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
	181	break;
	182
	183	case X25_CLEAR_CONFIRMATION:
	184	x25_disconnect(sk, 0, 0, 0);
	185	break;
	186
	187	default:
	188	break;
	189	}
	190
	191	return 0;
cb101ed2 MD	192
	193	out_clear:
	194	x25_write_internal(sk, X25_CLEAR_REQUEST);
	195	x25_start_t23timer(sk);
	196	return 0;
1da177e4 LT	197	}
	198
	199	/*
	200	* State machine for state 3, Connected State.
	201	* The handling of the timer(s) is in file x25_timer.c
	202	* Handling of state 0 and connection release is in af_x25.c.
	203	*/
	204	static int x25_state3_machine(struct sock sk, struct sk_buff skb, int frametype, int ns, int nr, int q, int d, int m)
	205	{
	206	int queued = 0;
	207	int modulus;
	208	struct x25_sock *x25 = x25_sk(sk);
f8e1d201	209
1da177e4 LT	210	modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
	211
	212	switch (frametype) {
	213
	214	case X25_RESET_REQUEST:
	215	x25_write_internal(sk, X25_RESET_CONFIRMATION);
	216	x25_stop_timer(sk);
	217	x25->condition = 0x00;
	218	x25->vs = 0;
	219	x25->vr = 0;
	220	x25->va = 0;
	221	x25->vl = 0;
	222	x25_requeue_frames(sk);
	223	break;
	224
	225	case X25_CLEAR_REQUEST:
cb101ed2 MD	226	if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
	227	goto out_clear;
	228
1da177e4 LT	229	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	230	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
	231	break;
	232
	233	case X25_RR:
	234	case X25_RNR:
	235	if (!x25_validate_nr(sk, nr)) {
	236	x25_clear_queues(sk);
	237	x25_write_internal(sk, X25_RESET_REQUEST);
	238	x25_start_t22timer(sk);
	239	x25->condition = 0x00;
	240	x25->vs = 0;
	241	x25->vr = 0;
	242	x25->va = 0;
	243	x25->vl = 0;
	244	x25->state = X25_STATE_4;
	245	} else {
	246	x25_frames_acked(sk, nr);
	247	if (frametype == X25_RNR) {
	248	x25->condition \|= X25_COND_PEER_RX_BUSY;
	249	} else {
	250	x25->condition &= ~X25_COND_PEER_RX_BUSY;
	251	}
	252	}
	253	break;
	254
	255	case X25_DATA: /* XXX */
	256	x25->condition &= ~X25_COND_PEER_RX_BUSY;
	257	if ((ns != x25->vr) \|\| !x25_validate_nr(sk, nr)) {
	258	x25_clear_queues(sk);
	259	x25_write_internal(sk, X25_RESET_REQUEST);
	260	x25_start_t22timer(sk);
	261	x25->condition = 0x00;
	262	x25->vs = 0;
	263	x25->vr = 0;
	264	x25->va = 0;
	265	x25->vl = 0;
	266	x25->state = X25_STATE_4;
	267	break;
	268	}
	269	x25_frames_acked(sk, nr);
	270	if (ns == x25->vr) {
	271	if (x25_queue_rx_frame(sk, skb, m) == 0) {
	272	x25->vr = (x25->vr + 1) % modulus;
	273	queued = 1;
	274	} else {
	275	/* Should never happen */
	276	x25_clear_queues(sk);
	277	x25_write_internal(sk, X25_RESET_REQUEST);
	278	x25_start_t22timer(sk);
	279	x25->condition = 0x00;
	280	x25->vs = 0;
	281	x25->vr = 0;
	282	x25->va = 0;
	283	x25->vl = 0;
	284	x25->state = X25_STATE_4;
	285	break;
	286	}
	287	if (atomic_read(&sk->sk_rmem_alloc) >
6bf1574e	288	(sk->sk_rcvbuf >> 1))
1da177e4 LT	289	x25->condition \|= X25_COND_OWN_RX_BUSY;
	290	}
	291	/*
	292	* If the window is full Ack it immediately, else
	293	* start the holdback timer.
	294	*/
	295	if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
	296	x25->condition &= ~X25_COND_ACK_PENDING;
	297	x25_stop_timer(sk);
	298	x25_enquiry_response(sk);
	299	} else {
	300	x25->condition \|= X25_COND_ACK_PENDING;
	301	x25_start_t2timer(sk);
	302	}
	303	break;
	304
	305	case X25_INTERRUPT_CONFIRMATION:
b7792e34	306	clear_bit(X25_INTERRUPT_FLAG, &x25->flags);
1da177e4 LT	307	break;
	308
	309	case X25_INTERRUPT:
	310	if (sock_flag(sk, SOCK_URGINLINE))
	311	queued = !sock_queue_rcv_skb(sk, skb);
	312	else {
	313	skb_set_owner_r(skb, sk);
	314	skb_queue_tail(&x25->interrupt_in_queue, skb);
	315	queued = 1;
	316	}
	317	sk_send_sigurg(sk);
	318	x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
	319	break;
	320
	321	default:
b73e9e3c	322	pr_warn("unknown %02X in state 3\n", frametype);
1da177e4 LT	323	break;
	324	}
	325
	326	return queued;
cb101ed2 MD	327
	328	out_clear:
	329	x25_write_internal(sk, X25_CLEAR_REQUEST);
	330	x25->state = X25_STATE_2;
	331	x25_start_t23timer(sk);
	332	return 0;
1da177e4 LT	333	}
	334
	335	/*
	336	* State machine for state 4, Awaiting Reset Confirmation State.
	337	* The handling of the timer(s) is in file x25_timer.c
	338	* Handling of state 0 and connection release is in af_x25.c.
	339	*/
	340	static int x25_state4_machine(struct sock sk, struct sk_buff skb, int frametype)
	341	{
cb101ed2 MD	342	struct x25_sock *x25 = x25_sk(sk);
cb101ed2 MD	343
1da177e4 LT	344	switch (frametype) {
	345
	346	case X25_RESET_REQUEST:
	347	x25_write_internal(sk, X25_RESET_CONFIRMATION);
	348	case X25_RESET_CONFIRMATION: {
1da177e4 LT	349	x25_stop_timer(sk);
	350	x25->condition = 0x00;
	351	x25->va = 0;
	352	x25->vr = 0;
	353	x25->vs = 0;
	354	x25->vl = 0;
	355	x25->state = X25_STATE_3;
	356	x25_requeue_frames(sk);
	357	break;
	358	}
	359	case X25_CLEAR_REQUEST:
cb101ed2 MD	360	if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 2))
	361	goto out_clear;
	362
1da177e4 LT	363	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	364	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
	365	break;
	366
	367	default:
	368	break;
	369	}
	370
	371	return 0;
cb101ed2 MD	372
	373	out_clear:
	374	x25_write_internal(sk, X25_CLEAR_REQUEST);
	375	x25->state = X25_STATE_2;
	376	x25_start_t23timer(sk);
	377	return 0;
1da177e4 LT	378	}
	379
	380	/* Higher level upcall for a LAPB frame */
	381	int x25_process_rx_frame(struct sock sk, struct sk_buff skb)
	382	{
	383	struct x25_sock *x25 = x25_sk(sk);
	384	int queued = 0, frametype, ns, nr, q, d, m;
	385
	386	if (x25->state == X25_STATE_0)
	387	return 0;
	388
	389	frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
	390
	391	switch (x25->state) {
fddc5f3e JP	392	case X25_STATE_1:
	393	queued = x25_state1_machine(sk, skb, frametype);
	394	break;
	395	case X25_STATE_2:
	396	queued = x25_state2_machine(sk, skb, frametype);
	397	break;
	398	case X25_STATE_3:
	399	queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
	400	break;
	401	case X25_STATE_4:
	402	queued = x25_state4_machine(sk, skb, frametype);
	403	break;
1da177e4 LT	404	}
	405
	406	x25_kick(sk);
	407
	408	return queued;
	409	}
	410
	411	int x25_backlog_rcv(struct sock sk, struct sk_buff skb)
	412	{
	413	int queued = x25_process_rx_frame(sk, skb);
	414
	415	if (!queued)
	416	kfree_skb(skb);
	417
	418	return 0;
	419	}