[linux.git] / net / x25 / x25_out.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	New timer architecture.
 *	2000-09-04	Henner Eisen	Prevented x25_output() skb leakage.
 *	2000-10-27	Henner Eisen	MSG_DONTWAIT for fragment allocation.
 *	2000-11-10	Henner Eisen	x25_send_iframe(): re-queued frames
 *					needed cleaned seq-number fields.
 */

#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/x25.h>

static int x25_pacsize_to_bytes(unsigned int pacsize)
{
	int bytes = 1;

	if (!pacsize)
		return 128;

	while (pacsize-- > 0)
		bytes *= 2;

	return bytes;
}

/*
 *	This is where all X.25 information frames pass.
 *
 *      Returns the amount of user data bytes sent on success
 *      or a negative error code on failure.
 */
int x25_output(struct sock *sk, struct sk_buff *skb)
{
	struct sk_buff *skbn;
	unsigned char header[X25_EXT_MIN_LEN];
	int err, frontlen, len;
	int sent=0, noblock = X25_SKB_CB(skb)->flags & MSG_DONTWAIT;
	struct x25_sock *x25 = x25_sk(sk);
	int header_len = x25->neighbour->extended ? X25_EXT_MIN_LEN :
						    X25_STD_MIN_LEN;
	int max_len = x25_pacsize_to_bytes(x25->facilities.pacsize_out);

	if (skb->len - header_len > max_len) {
		/* Save a copy of the Header */
		skb_copy_from_linear_data(skb, header, header_len);
		skb_pull(skb, header_len);

		frontlen = skb_headroom(skb);

		while (skb->len > 0) {
			release_sock(sk);
			skbn = sock_alloc_send_skb(sk, frontlen + max_len,
						   noblock, &err);
			lock_sock(sk);
			if (!skbn) {
				if (err == -EWOULDBLOCK && noblock){
					kfree_skb(skb);
					return sent;
				}
				SOCK_DEBUG(sk, "x25_output: fragment alloc"
					       " failed, err=%d, %d bytes "
					       "sent\n", err, sent);
				return err;
			}

			skb_reserve(skbn, frontlen);

			len = max_len > skb->len ? skb->len : max_len;

			/* Copy the user data */
			skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
			skb_pull(skb, len);

			/* Duplicate the Header */
			skb_push(skbn, header_len);
			skb_copy_to_linear_data(skbn, header, header_len);

			if (skb->len > 0) {
				if (x25->neighbour->extended)
					skbn->data[3] |= X25_EXT_M_BIT;
				else
					skbn->data[2] |= X25_STD_M_BIT;
			}

			skb_queue_tail(&sk->sk_write_queue, skbn);
			sent += len;
		}

		kfree_skb(skb);
	} else {
		skb_queue_tail(&sk->sk_write_queue, skb);
		sent = skb->len - header_len;
	}
	return sent;
}

/*
 *	This procedure is passed a buffer descriptor for an iframe. It builds
 *	the rest of the control part of the frame and then writes it out.
 */
static void x25_send_iframe(struct sock *sk, struct sk_buff *skb)
{
	struct x25_sock *x25 = x25_sk(sk);

	if (!skb)
		return;

	if (x25->neighbour->extended) {
		skb->data[2]  = (x25->vs << 1) & 0xFE;
		skb->data[3] &= X25_EXT_M_BIT;
		skb->data[3] |= (x25->vr << 1) & 0xFE;
	} else {
		skb->data[2] &= X25_STD_M_BIT;
		skb->data[2] |= (x25->vs << 1) & 0x0E;
		skb->data[2] |= (x25->vr << 5) & 0xE0;
	}

	x25_transmit_link(skb, x25->neighbour);
}

void x25_kick(struct sock *sk)
{
	struct sk_buff *skb, *skbn;
	unsigned short start, end;
	int modulus;
	struct x25_sock *x25 = x25_sk(sk);

	if (x25->state != X25_STATE_3)
		return;

	/*
	 *	Transmit interrupt data.
	 */
	if (skb_peek(&x25->interrupt_out_queue) != NULL &&
		!test_and_set_bit(X25_INTERRUPT_FLAG, &x25->flags)) {

		skb = skb_dequeue(&x25->interrupt_out_queue);
		x25_transmit_link(skb, x25->neighbour);
	}

	if (x25->condition & X25_COND_PEER_RX_BUSY)
		return;

	if (!skb_peek(&sk->sk_write_queue))
		return;

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

	start   = skb_peek(&x25->ack_queue) ? x25->vs : x25->va;
	end     = (x25->va + x25->facilities.winsize_out) % modulus;

	if (start == end)
		return;

	x25->vs = start;

	/*
	 * Transmit data until either we're out of data to send or
	 * the window is full.
	 */

	skb = skb_dequeue(&sk->sk_write_queue);

	do {
		if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
			skb_queue_head(&sk->sk_write_queue, skb);
			break;
		}

		skb_set_owner_w(skbn, sk);

		/*
		 * Transmit the frame copy.
		 */
		x25_send_iframe(sk, skbn);

		x25->vs = (x25->vs + 1) % modulus;

		/*
		 * Requeue the original data frame.
		 */
		skb_queue_tail(&x25->ack_queue, skb);

	} while (x25->vs != end &&
		 (skb = skb_dequeue(&sk->sk_write_queue)) != NULL);

	x25->vl         = x25->vr;
	x25->condition &= ~X25_COND_ACK_PENDING;

	x25_stop_timer(sk);
}

/*
 * The following routines are taken from page 170 of the 7th ARRL Computer
 * Networking Conference paper, as is the whole state machine.
 */

void x25_enquiry_response(struct sock *sk)
{
	struct x25_sock *x25 = x25_sk(sk);

	if (x25->condition & X25_COND_OWN_RX_BUSY)
		x25_write_internal(sk, X25_RNR);
	else
		x25_write_internal(sk, X25_RR);

	x25->vl         = x25->vr;
	x25->condition &= ~X25_COND_ACK_PENDING;

	x25_stop_timer(sk);
}
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 New timer architecture.
	19	* 2000-09-04 Henner Eisen Prevented x25_output() skb leakage.
	20	* 2000-10-27 Henner Eisen MSG_DONTWAIT for fragment allocation.
	21	* 2000-11-10 Henner Eisen x25_send_iframe(): re-queued frames
	22	* needed cleaned seq-number fields.
	23	*/
	24
5a0e3ad6	25	#include <linux/slab.h>
1da177e4 LT	26	#include <linux/socket.h>
	27	#include <linux/kernel.h>
	28	#include <linux/string.h>
	29	#include <linux/skbuff.h>
	30	#include <net/sock.h>
	31	#include <net/x25.h>
	32
	33	static int x25_pacsize_to_bytes(unsigned int pacsize)
	34	{
	35	int bytes = 1;
	36
	37	if (!pacsize)
	38	return 128;
	39
	40	while (pacsize-- > 0)
	41	bytes *= 2;
	42
	43	return bytes;
	44	}
	45
	46	/*
	47	* This is where all X.25 information frames pass.
	48	*
	49	* Returns the amount of user data bytes sent on success
	50	* or a negative error code on failure.
	51	*/
	52	int x25_output(struct sock sk, struct sk_buff skb)
	53	{
	54	struct sk_buff *skbn;
	55	unsigned char header[X25_EXT_MIN_LEN];
	56	int err, frontlen, len;
	57	int sent=0, noblock = X25_SKB_CB(skb)->flags & MSG_DONTWAIT;
	58	struct x25_sock *x25 = x25_sk(sk);
	59	int header_len = x25->neighbour->extended ? X25_EXT_MIN_LEN :
	60	X25_STD_MIN_LEN;
	61	int max_len = x25_pacsize_to_bytes(x25->facilities.pacsize_out);
	62
	63	if (skb->len - header_len > max_len) {
	64	/* Save a copy of the Header */
d626f62b	65	skb_copy_from_linear_data(skb, header, header_len);
1da177e4 LT	66	skb_pull(skb, header_len);
	67
	68	frontlen = skb_headroom(skb);
	69
	70	while (skb->len > 0) {
77b22836 AB	71	release_sock(sk);
	72	skbn = sock_alloc_send_skb(sk, frontlen + max_len,
	73	noblock, &err);
	74	lock_sock(sk);
	75	if (!skbn) {
1da177e4 LT	76	if (err == -EWOULDBLOCK && noblock){
	77	kfree_skb(skb);
	78	return sent;
	79	}
	80	SOCK_DEBUG(sk, "x25_output: fragment alloc"
	81	" failed, err=%d, %d bytes "
	82	"sent\n", err, sent);
	83	return err;
	84	}
f8e1d201	85
1da177e4 LT	86	skb_reserve(skbn, frontlen);
	87
	88	len = max_len > skb->len ? skb->len : max_len;
	89
	90	/* Copy the user data */
d626f62b	91	skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
1da177e4 LT	92	skb_pull(skb, len);
	93
	94	/* Duplicate the Header */
	95	skb_push(skbn, header_len);
27d7ff46	96	skb_copy_to_linear_data(skbn, header, header_len);
1da177e4 LT	97
	98	if (skb->len > 0) {
	99	if (x25->neighbour->extended)
	100	skbn->data[3] \|= X25_EXT_M_BIT;
	101	else
	102	skbn->data[2] \|= X25_STD_M_BIT;
	103	}
	104
	105	skb_queue_tail(&sk->sk_write_queue, skbn);
	106	sent += len;
	107	}
f8e1d201	108
1da177e4 LT	109	kfree_skb(skb);
	110	} else {
	111	skb_queue_tail(&sk->sk_write_queue, skb);
	112	sent = skb->len - header_len;
	113	}
	114	return sent;
	115	}
	116
f8e1d201	117	/*
1da177e4 LT	118	* This procedure is passed a buffer descriptor for an iframe. It builds
	119	* the rest of the control part of the frame and then writes it out.
	120	*/
	121	static void x25_send_iframe(struct sock sk, struct sk_buff skb)
	122	{
	123	struct x25_sock *x25 = x25_sk(sk);
	124
	125	if (!skb)
	126	return;
	127
	128	if (x25->neighbour->extended) {
	129	skb->data[2] = (x25->vs << 1) & 0xFE;
	130	skb->data[3] &= X25_EXT_M_BIT;
	131	skb->data[3] \|= (x25->vr << 1) & 0xFE;
	132	} else {
	133	skb->data[2] &= X25_STD_M_BIT;
	134	skb->data[2] \|= (x25->vs << 1) & 0x0E;
	135	skb->data[2] \|= (x25->vr << 5) & 0xE0;
	136	}
	137
f8e1d201	138	x25_transmit_link(skb, x25->neighbour);
1da177e4 LT	139	}
	140
	141	void x25_kick(struct sock *sk)
	142	{
	143	struct sk_buff skb, skbn;
	144	unsigned short start, end;
	145	int modulus;
	146	struct x25_sock *x25 = x25_sk(sk);
	147
	148	if (x25->state != X25_STATE_3)
	149	return;
	150
	151	/*
	152	* Transmit interrupt data.
	153	*/
b7792e34	154	if (skb_peek(&x25->interrupt_out_queue) != NULL &&
	155	!test_and_set_bit(X25_INTERRUPT_FLAG, &x25->flags)) {
	156
1da177e4 LT	157	skb = skb_dequeue(&x25->interrupt_out_queue);
	158	x25_transmit_link(skb, x25->neighbour);
	159	}
	160
	161	if (x25->condition & X25_COND_PEER_RX_BUSY)
	162	return;
	163
	164	if (!skb_peek(&sk->sk_write_queue))
	165	return;
	166
	167	modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
	168
	169	start = skb_peek(&x25->ack_queue) ? x25->vs : x25->va;
	170	end = (x25->va + x25->facilities.winsize_out) % modulus;
	171
	172	if (start == end)
	173	return;
	174
	175	x25->vs = start;
	176
	177	/*
	178	* Transmit data until either we're out of data to send or
	179	* the window is full.
	180	*/
	181
	182	skb = skb_dequeue(&sk->sk_write_queue);
	183
	184	do {
	185	if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
	186	skb_queue_head(&sk->sk_write_queue, skb);
	187	break;
	188	}
	189
	190	skb_set_owner_w(skbn, sk);
	191
	192	/*
	193	* Transmit the frame copy.
	194	*/
	195	x25_send_iframe(sk, skbn);
	196
	197	x25->vs = (x25->vs + 1) % modulus;
	198
	199	/*
	200	* Requeue the original data frame.
	201	*/
	202	skb_queue_tail(&x25->ack_queue, skb);
	203
	204	} while (x25->vs != end &&
	205	(skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
	206
	207	x25->vl = x25->vr;
	208	x25->condition &= ~X25_COND_ACK_PENDING;
	209
	210	x25_stop_timer(sk);
	211	}
	212
	213	/*
	214	* The following routines are taken from page 170 of the 7th ARRL Computer
	215	* Networking Conference paper, as is the whole state machine.
	216	*/
	217
	218	void x25_enquiry_response(struct sock *sk)
	219	{
	220	struct x25_sock *x25 = x25_sk(sk);
221
222	if (x25->condition & X25_COND_OWN_RX_BUSY)
223	x25_write_internal(sk, X25_RNR);
224	else
225	x25_write_internal(sk, X25_RR);
226
227	x25->vl = x25->vr;
228	x25->condition &= ~X25_COND_ACK_PENDING;
229
230	x25_stop_timer(sk);
231	}