[net-next-2.6.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);
		memcpy(skb_put(skbn, skbo->len), skbo->data, 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);
			memcpy(skb_put(skbn, skbo->len), skbo->data, 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
	58	skbo = skb_dequeue(&x25->fragment_queue);
	59	memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
	60	kfree_skb(skbo);
	61
	62	while ((skbo =
	63	skb_dequeue(&x25->fragment_queue)) != NULL) {
	64	skb_pull(skbo, (x25->neighbour->extended) ?
	65	X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
	66	memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
	67	kfree_skb(skbo);
	68	}
	69
f8e1d201	70	x25->fraglen = 0;
1da177e4 LT	71	}
	72
	73	skb_set_owner_r(skbn, sk);
	74	skb_queue_tail(&sk->sk_receive_queue, skbn);
	75	if (!sock_flag(sk, SOCK_DEAD))
	76	sk->sk_data_ready(sk, skbn->len);
	77
	78	return 0;
	79	}
	80
	81	/*
	82	* State machine for state 1, Awaiting Call Accepted State.
	83	* The handling of the timer(s) is in file x25_timer.c.
	84	* Handling of state 0 and connection release is in af_x25.c.
	85	*/
	86	static int x25_state1_machine(struct sock sk, struct sk_buff skb, int frametype)
	87	{
	88	struct x25_address source_addr, dest_addr;
	89
	90	switch (frametype) {
	91	case X25_CALL_ACCEPTED: {
	92	struct x25_sock *x25 = x25_sk(sk);
	93
	94	x25_stop_timer(sk);
	95	x25->condition = 0x00;
	96	x25->vs = 0;
	97	x25->va = 0;
	98	x25->vr = 0;
	99	x25->vl = 0;
	100	x25->state = X25_STATE_3;
	101	sk->sk_state = TCP_ESTABLISHED;
	102	/*
	103	* Parse the data in the frame.
	104	*/
	105	skb_pull(skb, X25_STD_MIN_LEN);
	106	skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
	107	skb_pull(skb,
	108	x25_parse_facilities(skb, &x25->facilities,
a64b7b93 SP	109	&x25->dte_facilities,
a64b7b93 SP	110	&x25->vc_facil_mask));
1da177e4 LT	111	/*
	112	* Copy any Call User Data.
	113	*/
	114	if (skb->len >= 0) {
d626f62b ACM	115	skb_copy_from_linear_data(skb,
	116	x25->calluserdata.cuddata,
	117	skb->len);
1da177e4 LT	118	x25->calluserdata.cudlength = skb->len;
	119	}
	120	if (!sock_flag(sk, SOCK_DEAD))
	121	sk->sk_state_change(sk);
	122	break;
	123	}
	124	case X25_CLEAR_REQUEST:
	125	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	126	x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
	127	break;
	128
	129	default:
	130	break;
	131	}
	132
	133	return 0;
	134	}
	135
	136	/*
	137	* State machine for state 2, Awaiting Clear Confirmation State.
	138	* The handling of the timer(s) is in file x25_timer.c
	139	* Handling of state 0 and connection release is in af_x25.c.
	140	*/
	141	static int x25_state2_machine(struct sock sk, struct sk_buff skb, int frametype)
	142	{
	143	switch (frametype) {
	144
	145	case X25_CLEAR_REQUEST:
	146	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	147	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
	148	break;
	149
	150	case X25_CLEAR_CONFIRMATION:
	151	x25_disconnect(sk, 0, 0, 0);
	152	break;
	153
	154	default:
	155	break;
	156	}
	157
	158	return 0;
	159	}
	160
	161	/*
	162	* State machine for state 3, Connected State.
	163	* The handling of the timer(s) is in file x25_timer.c
	164	* Handling of state 0 and connection release is in af_x25.c.
	165	*/
	166	static int x25_state3_machine(struct sock sk, struct sk_buff skb, int frametype, int ns, int nr, int q, int d, int m)
	167	{
	168	int queued = 0;
	169	int modulus;
	170	struct x25_sock *x25 = x25_sk(sk);
f8e1d201	171
1da177e4 LT	172	modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
	173
	174	switch (frametype) {
	175
	176	case X25_RESET_REQUEST:
	177	x25_write_internal(sk, X25_RESET_CONFIRMATION);
	178	x25_stop_timer(sk);
	179	x25->condition = 0x00;
	180	x25->vs = 0;
	181	x25->vr = 0;
	182	x25->va = 0;
	183	x25->vl = 0;
	184	x25_requeue_frames(sk);
	185	break;
	186
	187	case X25_CLEAR_REQUEST:
	188	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
	189	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
	190	break;
	191
	192	case X25_RR:
	193	case X25_RNR:
	194	if (!x25_validate_nr(sk, nr)) {
	195	x25_clear_queues(sk);
	196	x25_write_internal(sk, X25_RESET_REQUEST);
	197	x25_start_t22timer(sk);
	198	x25->condition = 0x00;
	199	x25->vs = 0;
	200	x25->vr = 0;
	201	x25->va = 0;
	202	x25->vl = 0;
	203	x25->state = X25_STATE_4;
	204	} else {
	205	x25_frames_acked(sk, nr);
	206	if (frametype == X25_RNR) {
	207	x25->condition \|= X25_COND_PEER_RX_BUSY;
	208	} else {
	209	x25->condition &= ~X25_COND_PEER_RX_BUSY;
	210	}
	211	}
	212	break;
	213
	214	case X25_DATA: /* XXX */
	215	x25->condition &= ~X25_COND_PEER_RX_BUSY;
	216	if ((ns != x25->vr) \|\| !x25_validate_nr(sk, nr)) {
	217	x25_clear_queues(sk);
	218	x25_write_internal(sk, X25_RESET_REQUEST);
	219	x25_start_t22timer(sk);
	220	x25->condition = 0x00;
	221	x25->vs = 0;
	222	x25->vr = 0;
	223	x25->va = 0;
	224	x25->vl = 0;
	225	x25->state = X25_STATE_4;
	226	break;
	227	}
	228	x25_frames_acked(sk, nr);
	229	if (ns == x25->vr) {
	230	if (x25_queue_rx_frame(sk, skb, m) == 0) {
	231	x25->vr = (x25->vr + 1) % modulus;
	232	queued = 1;
	233	} else {
	234	/* Should never happen */
	235	x25_clear_queues(sk);
236	x25_write_internal(sk, X25_RESET_REQUEST);
237	x25_start_t22timer(sk);
238	x25->condition = 0x00;
239	x25->vs = 0;
240	x25->vr = 0;
241	x25->va = 0;
242	x25->vl = 0;
243	x25->state = X25_STATE_4;
244	break;
245	}
246	if (atomic_read(&sk->sk_rmem_alloc) >
247	(sk->sk_rcvbuf / 2))
248	x25->condition \|= X25_COND_OWN_RX_BUSY;
249	}
250	/*
251	* If the window is full Ack it immediately, else
252	* start the holdback timer.
253	*/
254	if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
255	x25->condition &= ~X25_COND_ACK_PENDING;
256	x25_stop_timer(sk);
257	x25_enquiry_response(sk);
258	} else {
259	x25->condition \|= X25_COND_ACK_PENDING;
260	x25_start_t2timer(sk);
261	}
262	break;
263
264	case X25_INTERRUPT_CONFIRMATION:
265	x25->intflag = 0;
266	break;
267
268	case X25_INTERRUPT:
269	if (sock_flag(sk, SOCK_URGINLINE))
270	queued = !sock_queue_rcv_skb(sk, skb);
271	else {
272	skb_set_owner_r(skb, sk);
273	skb_queue_tail(&x25->interrupt_in_queue, skb);
274	queued = 1;
275	}
276	sk_send_sigurg(sk);
277	x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
278	break;
279
280	default:
281	printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
282	break;
283	}
284
285	return queued;
286	}
287
288	/*
289	* State machine for state 4, Awaiting Reset Confirmation State.
290	* The handling of the timer(s) is in file x25_timer.c
291	* Handling of state 0 and connection release is in af_x25.c.
292	*/
293	static int x25_state4_machine(struct sock sk, struct sk_buff skb, int frametype)
294	{
295	switch (frametype) {
296
297	case X25_RESET_REQUEST:
298	x25_write_internal(sk, X25_RESET_CONFIRMATION);
299	case X25_RESET_CONFIRMATION: {
300	struct x25_sock *x25 = x25_sk(sk);
301
302	x25_stop_timer(sk);
303	x25->condition = 0x00;
304	x25->va = 0;
305	x25->vr = 0;
306	x25->vs = 0;
307	x25->vl = 0;
308	x25->state = X25_STATE_3;
309	x25_requeue_frames(sk);
310	break;
311	}
312	case X25_CLEAR_REQUEST:
313	x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
314	x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
315	break;
316
317	default:
318	break;
319	}
320
321	return 0;
322	}
323
324	/* Higher level upcall for a LAPB frame */
325	int x25_process_rx_frame(struct sock sk, struct sk_buff skb)
326	{
327	struct x25_sock *x25 = x25_sk(sk);
328	int queued = 0, frametype, ns, nr, q, d, m;
329
330	if (x25->state == X25_STATE_0)
331	return 0;
332
333	frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
334
335	switch (x25->state) {
336	case X25_STATE_1:
337	queued = x25_state1_machine(sk, skb, frametype);
338	break;
339	case X25_STATE_2:
340	queued = x25_state2_machine(sk, skb, frametype);
341	break;
342	case X25_STATE_3:
343	queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
344	break;
345	case X25_STATE_4:
346	queued = x25_state4_machine(sk, skb, frametype);
347	break;
348	}
349
350	x25_kick(sk);
351
352	return queued;
353	}
354
355	int x25_backlog_rcv(struct sock sk, struct sk_buff skb)
356	{
357	int queued = x25_process_rx_frame(sk, skb);
358
359	if (!queued)
360	kfree_skb(skb);
361
362	return 0;
363	}