[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.
 */

#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, skbn->len);

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