[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/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;

	switch (frametype) {
		case X25_CALL_ACCEPTED: {
			struct x25_sock *x25 = x25_sk(sk);

			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.
			 */
			skb_pull(skb, X25_STD_MIN_LEN);
			skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
			skb_pull(skb,
				 x25_parse_facilities(skb, &x25->facilities,
						&x25->dte_facilities,
						&x25->vc_facil_mask));
			/*
			 *	Copy any Call User Data.
			 */
			if (skb->len >= 0) {
				skb_copy_from_linear_data(skb,
					      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:
			x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
			x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
			break;

		default:
			break;
	}

	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:
			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;
}

/*
 * 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:
			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 / 2))
					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:
			x25->intflag = 0;
			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;
}

/*
 * 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)
{
	switch (frametype) {

		case X25_RESET_REQUEST:
			x25_write_internal(sk, X25_RESET_CONFIRMATION);
		case X25_RESET_CONFIRMATION: {
			struct x25_sock *x25 = x25_sk(sk);

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

		default:
			break;
	}

	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
	26	#include <linux/errno.h>
	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	static int x25_queue_rx_frame(struct sock sk, struct sk_buff skb, int more)
	35	{
	36	struct sk_buff skbo, skbn = skb;
	37	struct x25_sock *x25 = x25_sk(sk);
	38
	39	if (more) {
	40	x25->fraglen += skb->len;
	41	skb_queue_tail(&x25->fragment_queue, skb);
	42	skb_set_owner_r(skb, sk);
	43	return 0;
	44	}
	45
	46	if (!more && x25->fraglen > 0) { /* End of fragment */
	47	int len = x25->fraglen + skb->len;
	48
	49	if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
	50	kfree_skb(skb);
	51	return 1;
	52	}
	53
	54	skb_queue_tail(&x25->fragment_queue, skb);
	55
badff6d0	56	skb_reset_transport_header(skbn);
1da177e4 LT	57
1da177e4 LT	58	skbo = skb_dequeue(&x25->fragment_queue);
1a4e2d09 ACM	59	skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
1a4e2d09 ACM	60	skbo->len);
1da177e4 LT	61	kfree_skb(skbo);
	62
	63	while ((skbo =
	64	skb_dequeue(&x25->fragment_queue)) != NULL) {
	65	skb_pull(skbo, (x25->neighbour->extended) ?
	66	X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
1a4e2d09 ACM	67	skb_copy_from_linear_data(skbo,
	68	skb_put(skbn, skbo->len),
	69	skbo->len);
1da177e4 LT	70	kfree_skb(skbo);
	71	}
	72
f8e1d201	73	x25->fraglen = 0;
1da177e4 LT	74	}
	75
	76	skb_set_owner_r(skbn, sk);
	77	skb_queue_tail(&sk->sk_receive_queue, skbn);
	78	if (!sock_flag(sk, SOCK_DEAD))
	79	sk->sk_data_ready(sk, skbn->len);
	80
	81	return 0;
	82	}
	83
	84	/*
	85	* State machine for state 1, Awaiting Call Accepted State.
	86	* The handling of the timer(s) is in file x25_timer.c.
	87	* Handling of state 0 and connection release is in af_x25.c.
	88	*/
	89	static int x25_state1_machine(struct sock sk, struct sk_buff skb, int frametype)
	90	{
	91	struct x25_address source_addr, dest_addr;
	92
	93	switch (frametype) {
	94	case X25_CALL_ACCEPTED: {
	95	struct x25_sock *x25 = x25_sk(sk);
	96
	97	x25_stop_timer(sk);
	98	x25->condition = 0x00;
	99	x25->vs = 0;
	100	x25->va = 0;
	101	x25->vr = 0;
	102	x25->vl = 0;
	103	x25->state = X25_STATE_3;
	104	sk->sk_state = TCP_ESTABLISHED;
	105	/*
	106	* Parse the data in the frame.
	107	*/
	108	skb_pull(skb, X25_STD_MIN_LEN);
	109	skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
	110	skb_pull(skb,
	111	x25_parse_facilities(skb, &x25->facilities,
a64b7b93 SP	112	&x25->dte_facilities,
a64b7b93 SP	113	&x25->vc_facil_mask));
1da177e4 LT	114	/*
	115	* Copy any Call User Data.
	116	*/
	117	if (skb->len >= 0) {
d626f62b ACM	118	skb_copy_from_linear_data(skb,
	119	x25->calluserdata.cuddata,
	120	skb->len);
1da177e4 LT	121	x25->calluserdata.cudlength = skb->len;
	122	}
	123	if (!sock_flag(sk, SOCK_DEAD))
	124	sk->sk_state_change(sk);
	125	break;
	126	}
	127	case X25_CLEAR_REQUEST:
	128	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	129	x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
	130	break;
	131
	132	default:
	133	break;
	134	}
	135
	136	return 0;
	137	}
	138
	139	/*
	140	* State machine for state 2, Awaiting Clear Confirmation State.
	141	* The handling of the timer(s) is in file x25_timer.c
	142	* Handling of state 0 and connection release is in af_x25.c.
	143	*/
	144	static int x25_state2_machine(struct sock sk, struct sk_buff skb, int frametype)
	145	{
	146	switch (frametype) {
	147
	148	case X25_CLEAR_REQUEST:
	149	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	150	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
	151	break;
	152
	153	case X25_CLEAR_CONFIRMATION:
	154	x25_disconnect(sk, 0, 0, 0);
	155	break;
	156
	157	default:
	158	break;
	159	}
	160
	161	return 0;
	162	}
	163
	164	/*
	165	* State machine for state 3, Connected 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_state3_machine(struct sock sk, struct sk_buff skb, int frametype, int ns, int nr, int q, int d, int m)
	170	{
	171	int queued = 0;
	172	int modulus;
	173	struct x25_sock *x25 = x25_sk(sk);
f8e1d201	174
1da177e4 LT	175	modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
	176
	177	switch (frametype) {
	178
	179	case X25_RESET_REQUEST:
	180	x25_write_internal(sk, X25_RESET_CONFIRMATION);
	181	x25_stop_timer(sk);
	182	x25->condition = 0x00;
	183	x25->vs = 0;
	184	x25->vr = 0;
	185	x25->va = 0;
	186	x25->vl = 0;
	187	x25_requeue_frames(sk);
	188	break;
	189
	190	case X25_CLEAR_REQUEST:
	191	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	192	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
	193	break;
	194
	195	case X25_RR:
	196	case X25_RNR:
	197	if (!x25_validate_nr(sk, nr)) {
	198	x25_clear_queues(sk);
	199	x25_write_internal(sk, X25_RESET_REQUEST);
	200	x25_start_t22timer(sk);
	201	x25->condition = 0x00;
	202	x25->vs = 0;
	203	x25->vr = 0;
	204	x25->va = 0;
	205	x25->vl = 0;
	206	x25->state = X25_STATE_4;
	207	} else {
	208	x25_frames_acked(sk, nr);
	209	if (frametype == X25_RNR) {
	210	x25->condition \|= X25_COND_PEER_RX_BUSY;
	211	} else {
	212	x25->condition &= ~X25_COND_PEER_RX_BUSY;
	213	}
	214	}
	215	break;
	216
	217	case X25_DATA: /* XXX */
	218	x25->condition &= ~X25_COND_PEER_RX_BUSY;
	219	if ((ns != x25->vr) \|\| !x25_validate_nr(sk, nr)) {
	220	x25_clear_queues(sk);
	221	x25_write_internal(sk, X25_RESET_REQUEST);
	222	x25_start_t22timer(sk);
	223	x25->condition = 0x00;
	224	x25->vs = 0;
	225	x25->vr = 0;
	226	x25->va = 0;
	227	x25->vl = 0;
	228	x25->state = X25_STATE_4;
	229	break;
	230	}
	231	x25_frames_acked(sk, nr);
	232	if (ns == x25->vr) {
	233	if (x25_queue_rx_frame(sk, skb, m) == 0) {
	234	x25->vr = (x25->vr + 1) % modulus;
	235	queued = 1;
	236	} else {
	237	/* Should never happen */
	238	x25_clear_queues(sk);
239	x25_write_internal(sk, X25_RESET_REQUEST);
240	x25_start_t22timer(sk);
241	x25->condition = 0x00;
242	x25->vs = 0;
243	x25->vr = 0;
244	x25->va = 0;
245	x25->vl = 0;
246	x25->state = X25_STATE_4;
247	break;
248	}
249	if (atomic_read(&sk->sk_rmem_alloc) >
250	(sk->sk_rcvbuf / 2))
251	x25->condition \|= X25_COND_OWN_RX_BUSY;
252	}
253	/*
254	* If the window is full Ack it immediately, else
255	* start the holdback timer.
256	*/
257	if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
258	x25->condition &= ~X25_COND_ACK_PENDING;
259	x25_stop_timer(sk);
260	x25_enquiry_response(sk);
261	} else {
262	x25->condition \|= X25_COND_ACK_PENDING;
263	x25_start_t2timer(sk);
264	}
265	break;
266
267	case X25_INTERRUPT_CONFIRMATION:
268	x25->intflag = 0;
269	break;
270
271	case X25_INTERRUPT:
272	if (sock_flag(sk, SOCK_URGINLINE))
273	queued = !sock_queue_rcv_skb(sk, skb);
274	else {
275	skb_set_owner_r(skb, sk);
276	skb_queue_tail(&x25->interrupt_in_queue, skb);
277	queued = 1;
278	}
279	sk_send_sigurg(sk);
280	x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
281	break;
282
283	default:
284	printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
285	break;
286	}
287
288	return queued;
289	}
290
291	/*
292	* State machine for state 4, Awaiting Reset Confirmation State.
293	* The handling of the timer(s) is in file x25_timer.c
294	* Handling of state 0 and connection release is in af_x25.c.
295	*/
296	static int x25_state4_machine(struct sock sk, struct sk_buff skb, int frametype)
297	{
298	switch (frametype) {
299
300	case X25_RESET_REQUEST:
301	x25_write_internal(sk, X25_RESET_CONFIRMATION);
302	case X25_RESET_CONFIRMATION: {
303	struct x25_sock *x25 = x25_sk(sk);
304
305	x25_stop_timer(sk);
306	x25->condition = 0x00;
307	x25->va = 0;
308	x25->vr = 0;
309	x25->vs = 0;
310	x25->vl = 0;
311	x25->state = X25_STATE_3;
312	x25_requeue_frames(sk);
313	break;
314	}
315	case X25_CLEAR_REQUEST:
316	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
317	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
318	break;
319
320	default:
321	break;
322	}
323
324	return 0;
325	}
326
327	/* Higher level upcall for a LAPB frame */
328	int x25_process_rx_frame(struct sock sk, struct sk_buff skb)
329	{
330	struct x25_sock *x25 = x25_sk(sk);
331	int queued = 0, frametype, ns, nr, q, d, m;
332
333	if (x25->state == X25_STATE_0)
334	return 0;
335
336	frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
337
338	switch (x25->state) {
339	case X25_STATE_1:
340	queued = x25_state1_machine(sk, skb, frametype);
341	break;
342	case X25_STATE_2:
343	queued = x25_state2_machine(sk, skb, frametype);
344	break;
345	case X25_STATE_3:
346	queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
347	break;
348	case X25_STATE_4:
349	queued = x25_state4_machine(sk, skb, frametype);
350	break;
351	}
352
353	x25_kick(sk);
354
355	return queued;
356	}
357
358	int x25_backlog_rcv(struct sock sk, struct sk_buff skb)
359	{
360	int queued = x25_process_rx_frame(sk, skb);
361
362	if (!queued)
363	kfree_skb(skb);
364
365	return 0;
366	}