[linux.git] / net / x25 / x25_dev.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.
 *      2000-09-04	Henner Eisen	Prevent freeing a dangling skb.
 */

#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/if_arp.h>
#include <net/x25.h>
#include <net/x25device.h>

static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb)
{
	struct sock *sk;
	unsigned short frametype;
	unsigned int lci;

	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
		return 0;

	frametype = skb->data[2];
	lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);

	/*
	 *	LCI of zero is always for us, and its always a link control
	 *	frame.
	 */
	if (lci == 0) {
		x25_link_control(skb, nb, frametype);
		return 0;
	}

	/*
	 *	Find an existing socket.
	 */
	if ((sk = x25_find_socket(lci, nb)) != NULL) {
		int queued = 1;

		skb_reset_transport_header(skb);
		bh_lock_sock(sk);
		if (!sock_owned_by_user(sk)) {
			queued = x25_process_rx_frame(sk, skb);
		} else {
			queued = !sk_add_backlog(sk, skb, sk->sk_rcvbuf);
		}
		bh_unlock_sock(sk);
		sock_put(sk);
		return queued;
	}

	/*
	 *	Is is a Call Request ? if so process it.
	 */
	if (frametype == X25_CALL_REQUEST)
		return x25_rx_call_request(skb, nb, lci);

	/*
	 * 	Its not a Call Request, nor is it a control frame.
	 *	Can we forward it?
	 */

	if (x25_forward_data(lci, nb, skb)) {
		if (frametype == X25_CLEAR_CONFIRMATION) {
			x25_clear_forward_by_lci(lci);
		}
		kfree_skb(skb);
		return 1;
	}

/*
	x25_transmit_clear_request(nb, lci, 0x0D);
*/

	if (frametype != X25_CLEAR_CONFIRMATION)
		printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);

	return 0;
}

int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev,
			   struct packet_type *ptype, struct net_device *orig_dev)
{
	struct sk_buff *nskb;
	struct x25_neigh *nb;

	if (!net_eq(dev_net(dev), &init_net))
		goto drop;

	nskb = skb_copy(skb, GFP_ATOMIC);
	if (!nskb)
		goto drop;
	kfree_skb(skb);
	skb = nskb;

	/*
	 * Packet received from unrecognised device, throw it away.
	 */
	nb = x25_get_neigh(dev);
	if (!nb) {
		printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);
		goto drop;
	}

	if (!pskb_may_pull(skb, 1))
		return 0;

	switch (skb->data[0]) {

	case X25_IFACE_DATA:
		skb_pull(skb, 1);
		if (x25_receive_data(skb, nb)) {
			x25_neigh_put(nb);
			goto out;
		}
		break;

	case X25_IFACE_CONNECT:
		x25_link_established(nb);
		break;

	case X25_IFACE_DISCONNECT:
		x25_link_terminated(nb);
		break;
	}
	x25_neigh_put(nb);
drop:
	kfree_skb(skb);
out:
	return 0;
}

void x25_establish_link(struct x25_neigh *nb)
{
	struct sk_buff *skb;
	unsigned char *ptr;

	switch (nb->dev->type) {
	case ARPHRD_X25:
		if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
			printk(KERN_ERR "x25_dev: out of memory\n");
			return;
		}
		ptr  = skb_put(skb, 1);
		*ptr = X25_IFACE_CONNECT;
		break;

#if IS_ENABLED(CONFIG_LLC)
	case ARPHRD_ETHER:
		return;
#endif
	default:
		return;
	}

	skb->protocol = htons(ETH_P_X25);
	skb->dev      = nb->dev;

	dev_queue_xmit(skb);
}

void x25_terminate_link(struct x25_neigh *nb)
{
	struct sk_buff *skb;
	unsigned char *ptr;

#if IS_ENABLED(CONFIG_LLC)
	if (nb->dev->type == ARPHRD_ETHER)
		return;
#endif
	if (nb->dev->type != ARPHRD_X25)
		return;

	skb = alloc_skb(1, GFP_ATOMIC);
	if (!skb) {
		printk(KERN_ERR "x25_dev: out of memory\n");
		return;
	}

	ptr  = skb_put(skb, 1);
	*ptr = X25_IFACE_DISCONNECT;

	skb->protocol = htons(ETH_P_X25);
	skb->dev      = nb->dev;
	dev_queue_xmit(skb);
}

void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb)
{
	unsigned char *dptr;

	skb_reset_network_header(skb);

	switch (nb->dev->type) {
	case ARPHRD_X25:
		dptr  = skb_push(skb, 1);
		*dptr = X25_IFACE_DATA;
		break;

#if IS_ENABLED(CONFIG_LLC)
	case ARPHRD_ETHER:
		kfree_skb(skb);
		return;
#endif
	default:
		kfree_skb(skb);
		return;
	}

	skb->protocol = htons(ETH_P_X25);
	skb->dev      = nb->dev;

	dev_queue_xmit(skb);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* X.25 Packet Layer release 002
	3	*
f8e1d201 YH	4	* This is ALPHA test software. This code may break your machine, randomly fail to work with new
f8e1d201 YH	5	* releases, misbehave and/or generally screw up. It might even work.
1da177e4 LT	6	*
	7	* This code REQUIRES 2.1.15 or higher
	8	*
	9	* This module:
	10	* This module is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public License
	12	* as published by the Free Software Foundation; either version
	13	* 2 of the License, or (at your option) any later version.
	14	*
	15	* History
	16	* X.25 001 Jonathan Naylor Started coding.
	17	* 2000-09-04 Henner Eisen Prevent freeing a dangling skb.
	18	*/
	19
1da177e4 LT	20	#include <linux/kernel.h>
	21	#include <linux/netdevice.h>
	22	#include <linux/skbuff.h>
5a0e3ad6	23	#include <linux/slab.h>
1da177e4 LT	24	#include <net/sock.h>
	25	#include <linux/if_arp.h>
	26	#include <net/x25.h>
5ebfbc06	27	#include <net/x25device.h>
1da177e4 LT	28
	29	static int x25_receive_data(struct sk_buff skb, struct x25_neigh nb)
	30	{
	31	struct sock *sk;
	32	unsigned short frametype;
	33	unsigned int lci;
	34
cb101ed2 MD	35	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
	36	return 0;
	37
1da177e4	38	frametype = skb->data[2];
f8e1d201	39	lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
1da177e4 LT	40
	41	/*
	42	* LCI of zero is always for us, and its always a link control
	43	* frame.
	44	*/
	45	if (lci == 0) {
	46	x25_link_control(skb, nb, frametype);
	47	return 0;
	48	}
	49
	50	/*
	51	* Find an existing socket.
	52	*/
	53	if ((sk = x25_find_socket(lci, nb)) != NULL) {
	54	int queued = 1;
	55
badff6d0	56	skb_reset_transport_header(skb);
1da177e4 LT	57	bh_lock_sock(sk);
	58	if (!sock_owned_by_user(sk)) {
	59	queued = x25_process_rx_frame(sk, skb);
	60	} else {
f545a38f	61	queued = !sk_add_backlog(sk, skb, sk->sk_rcvbuf);
1da177e4 LT	62	}
1da177e4 LT	63	bh_unlock_sock(sk);
9d0f7d29	64	sock_put(sk);
1da177e4 LT	65	return queued;
	66	}
	67
	68	/*
	69	* Is is a Call Request ? if so process it.
	70	*/
	71	if (frametype == X25_CALL_REQUEST)
	72	return x25_rx_call_request(skb, nb, lci);
	73
	74	/*
95a9dc43 AH	75	* Its not a Call Request, nor is it a control frame.
95a9dc43 AH	76	* Can we forward it?
1da177e4	77	*/
95a9dc43 AH	78
	79	if (x25_forward_data(lci, nb, skb)) {
	80	if (frametype == X25_CLEAR_CONFIRMATION) {
	81	x25_clear_forward_by_lci(lci);
	82	}
	83	kfree_skb(skb);
	84	return 1;
	85	}
	86
1da177e4 LT	87	/*
	88	x25_transmit_clear_request(nb, lci, 0x0D);
	89	*/
	90
	91	if (frametype != X25_CLEAR_CONFIRMATION)
	92	printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);
	93
	94	return 0;
	95	}
	96
	97	int x25_lapb_receive_frame(struct sk_buff skb, struct net_device dev,
f2ccd8fa	98	struct packet_type ptype, struct net_device orig_dev)
1da177e4 LT	99	{
	100	struct sk_buff *nskb;
	101	struct x25_neigh *nb;
	102
721499e8	103	if (!net_eq(dev_net(dev), &init_net))
e730c155 EB	104	goto drop;
e730c155 EB	105
1da177e4 LT	106	nskb = skb_copy(skb, GFP_ATOMIC);
	107	if (!nskb)
	108	goto drop;
	109	kfree_skb(skb);
	110	skb = nskb;
	111
	112	/*
	113	* Packet received from unrecognised device, throw it away.
	114	*/
	115	nb = x25_get_neigh(dev);
	116	if (!nb) {
	117	printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);
	118	goto drop;
	119	}
	120
cb101ed2 MD	121	if (!pskb_may_pull(skb, 1))
	122	return 0;
	123
1da177e4	124	switch (skb->data[0]) {
5ebfbc06 AH	125
	126	case X25_IFACE_DATA:
	127	skb_pull(skb, 1);
	128	if (x25_receive_data(skb, nb)) {
	129	x25_neigh_put(nb);
	130	goto out;
	131	}
	132	break;
	133
	134	case X25_IFACE_CONNECT:
	135	x25_link_established(nb);
	136	break;
	137
	138	case X25_IFACE_DISCONNECT:
	139	x25_link_terminated(nb);
	140	break;
1da177e4 LT	141	}
	142	x25_neigh_put(nb);
	143	drop:
	144	kfree_skb(skb);
	145	out:
	146	return 0;
	147	}
	148
	149	void x25_establish_link(struct x25_neigh *nb)
	150	{
	151	struct sk_buff *skb;
	152	unsigned char *ptr;
	153
	154	switch (nb->dev->type) {
fddc5f3e JP	155	case ARPHRD_X25:
	156	if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
	157	printk(KERN_ERR "x25_dev: out of memory\n");
	158	return;
	159	}
	160	ptr = skb_put(skb, 1);
	161	*ptr = X25_IFACE_CONNECT;
	162	break;
1da177e4	163
29c36262	164	#if IS_ENABLED(CONFIG_LLC)
fddc5f3e JP	165	case ARPHRD_ETHER:
fddc5f3e JP	166	return;
1da177e4	167	#endif
fddc5f3e JP	168	default:
fddc5f3e JP	169	return;
1da177e4 LT	170	}
	171
	172	skb->protocol = htons(ETH_P_X25);
	173	skb->dev = nb->dev;
	174
	175	dev_queue_xmit(skb);
	176	}
	177
	178	void x25_terminate_link(struct x25_neigh *nb)
	179	{
	180	struct sk_buff *skb;
	181	unsigned char *ptr;
	182
29c36262	183	#if IS_ENABLED(CONFIG_LLC)
1da177e4 LT	184	if (nb->dev->type == ARPHRD_ETHER)
	185	return;
	186	#endif
	187	if (nb->dev->type != ARPHRD_X25)
	188	return;
	189
	190	skb = alloc_skb(1, GFP_ATOMIC);
	191	if (!skb) {
	192	printk(KERN_ERR "x25_dev: out of memory\n");
	193	return;
	194	}
	195
	196	ptr = skb_put(skb, 1);
5ebfbc06	197	*ptr = X25_IFACE_DISCONNECT;
1da177e4 LT	198
	199	skb->protocol = htons(ETH_P_X25);
	200	skb->dev = nb->dev;
	201	dev_queue_xmit(skb);
	202	}
	203
	204	void x25_send_frame(struct sk_buff skb, struct x25_neigh nb)
	205	{
	206	unsigned char *dptr;
	207
c1d2bbe1	208	skb_reset_network_header(skb);
1da177e4 LT	209
1da177e4 LT	210	switch (nb->dev->type) {
fddc5f3e JP	211	case ARPHRD_X25:
	212	dptr = skb_push(skb, 1);
	213	*dptr = X25_IFACE_DATA;
	214	break;
1da177e4	215
29c36262	216	#if IS_ENABLED(CONFIG_LLC)
fddc5f3e JP	217	case ARPHRD_ETHER:
	218	kfree_skb(skb);
	219	return;
1da177e4	220	#endif
fddc5f3e JP	221	default:
	222	kfree_skb(skb);
	223	return;
1da177e4 LT	224	}
	225
	226	skb->protocol = htons(ETH_P_X25);
	227	skb->dev = nb->dev;
	228
	229	dev_queue_xmit(skb);
	230	}