[mirror_ubuntu-bionic-kernel.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.
 */

#define pr_fmt(fmt) "X25: " fmt

#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)
		pr_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) {
		pr_debug("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) {
			pr_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) {
		pr_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
b73e9e3c	20	#define pr_fmt(fmt) "X25: " fmt
b73e9e3c	21
1da177e4 LT	22	#include <linux/kernel.h>
	23	#include <linux/netdevice.h>
	24	#include <linux/skbuff.h>
5a0e3ad6	25	#include <linux/slab.h>
1da177e4 LT	26	#include <net/sock.h>
	27	#include <linux/if_arp.h>
	28	#include <net/x25.h>
5ebfbc06	29	#include <net/x25device.h>
1da177e4 LT	30
	31	static int x25_receive_data(struct sk_buff skb, struct x25_neigh nb)
	32	{
	33	struct sock *sk;
	34	unsigned short frametype;
	35	unsigned int lci;
	36
cb101ed2 MD	37	if (!pskb_may_pull(skb, X25_STD_MIN_LEN))
	38	return 0;
	39
1da177e4	40	frametype = skb->data[2];
f8e1d201	41	lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
1da177e4 LT	42
	43	/*
	44	* LCI of zero is always for us, and its always a link control
	45	* frame.
	46	*/
	47	if (lci == 0) {
	48	x25_link_control(skb, nb, frametype);
	49	return 0;
	50	}
	51
	52	/*
	53	* Find an existing socket.
	54	*/
	55	if ((sk = x25_find_socket(lci, nb)) != NULL) {
	56	int queued = 1;
	57
badff6d0	58	skb_reset_transport_header(skb);
1da177e4 LT	59	bh_lock_sock(sk);
	60	if (!sock_owned_by_user(sk)) {
	61	queued = x25_process_rx_frame(sk, skb);
	62	} else {
f545a38f	63	queued = !sk_add_backlog(sk, skb, sk->sk_rcvbuf);
1da177e4 LT	64	}
1da177e4 LT	65	bh_unlock_sock(sk);
9d0f7d29	66	sock_put(sk);
1da177e4 LT	67	return queued;
	68	}
	69
	70	/*
	71	* Is is a Call Request ? if so process it.
	72	*/
	73	if (frametype == X25_CALL_REQUEST)
	74	return x25_rx_call_request(skb, nb, lci);
	75
	76	/*
95a9dc43 AH	77	* Its not a Call Request, nor is it a control frame.
95a9dc43 AH	78	* Can we forward it?
1da177e4	79	*/
95a9dc43 AH	80
	81	if (x25_forward_data(lci, nb, skb)) {
	82	if (frametype == X25_CLEAR_CONFIRMATION) {
	83	x25_clear_forward_by_lci(lci);
	84	}
	85	kfree_skb(skb);
	86	return 1;
	87	}
	88
1da177e4 LT	89	/*
	90	x25_transmit_clear_request(nb, lci, 0x0D);
	91	*/
	92
	93	if (frametype != X25_CLEAR_CONFIRMATION)
b73e9e3c	94	pr_debug("x25_receive_data(): unknown frame type %2x\n",frametype);
1da177e4 LT	95
	96	return 0;
	97	}
	98
	99	int x25_lapb_receive_frame(struct sk_buff skb, struct net_device dev,
f2ccd8fa	100	struct packet_type ptype, struct net_device orig_dev)
1da177e4 LT	101	{
	102	struct sk_buff *nskb;
	103	struct x25_neigh *nb;
	104
721499e8	105	if (!net_eq(dev_net(dev), &init_net))
e730c155 EB	106	goto drop;
e730c155 EB	107
1da177e4 LT	108	nskb = skb_copy(skb, GFP_ATOMIC);
	109	if (!nskb)
	110	goto drop;
	111	kfree_skb(skb);
	112	skb = nskb;
	113
	114	/*
	115	* Packet received from unrecognised device, throw it away.
	116	*/
	117	nb = x25_get_neigh(dev);
	118	if (!nb) {
b73e9e3c	119	pr_debug("unknown neighbour - %s\n", dev->name);
1da177e4 LT	120	goto drop;
	121	}
	122
cb101ed2 MD	123	if (!pskb_may_pull(skb, 1))
	124	return 0;
	125
1da177e4	126	switch (skb->data[0]) {
5ebfbc06 AH	127
	128	case X25_IFACE_DATA:
	129	skb_pull(skb, 1);
	130	if (x25_receive_data(skb, nb)) {
	131	x25_neigh_put(nb);
	132	goto out;
	133	}
	134	break;
	135
	136	case X25_IFACE_CONNECT:
	137	x25_link_established(nb);
	138	break;
	139
	140	case X25_IFACE_DISCONNECT:
	141	x25_link_terminated(nb);
	142	break;
1da177e4 LT	143	}
	144	x25_neigh_put(nb);
	145	drop:
	146	kfree_skb(skb);
	147	out:
	148	return 0;
	149	}
	150
	151	void x25_establish_link(struct x25_neigh *nb)
	152	{
	153	struct sk_buff *skb;
	154	unsigned char *ptr;
	155
	156	switch (nb->dev->type) {
fddc5f3e JP	157	case ARPHRD_X25:
fddc5f3e JP	158	if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
b73e9e3c	159	pr_err("x25_dev: out of memory\n");
fddc5f3e JP	160	return;
	161	}
	162	ptr = skb_put(skb, 1);
	163	*ptr = X25_IFACE_CONNECT;
	164	break;
1da177e4	165
29c36262	166	#if IS_ENABLED(CONFIG_LLC)
fddc5f3e JP	167	case ARPHRD_ETHER:
fddc5f3e JP	168	return;
1da177e4	169	#endif
fddc5f3e JP	170	default:
fddc5f3e JP	171	return;
1da177e4 LT	172	}
	173
	174	skb->protocol = htons(ETH_P_X25);
	175	skb->dev = nb->dev;
	176
	177	dev_queue_xmit(skb);
	178	}
	179
	180	void x25_terminate_link(struct x25_neigh *nb)
	181	{
	182	struct sk_buff *skb;
	183	unsigned char *ptr;
	184
29c36262	185	#if IS_ENABLED(CONFIG_LLC)
1da177e4 LT	186	if (nb->dev->type == ARPHRD_ETHER)
	187	return;
	188	#endif
	189	if (nb->dev->type != ARPHRD_X25)
	190	return;
	191
	192	skb = alloc_skb(1, GFP_ATOMIC);
	193	if (!skb) {
b73e9e3c	194	pr_err("x25_dev: out of memory\n");
1da177e4 LT	195	return;
	196	}
	197
	198	ptr = skb_put(skb, 1);
5ebfbc06	199	*ptr = X25_IFACE_DISCONNECT;
1da177e4 LT	200
	201	skb->protocol = htons(ETH_P_X25);
	202	skb->dev = nb->dev;
	203	dev_queue_xmit(skb);
	204	}
	205
	206	void x25_send_frame(struct sk_buff skb, struct x25_neigh nb)
	207	{
	208	unsigned char *dptr;
	209
c1d2bbe1	210	skb_reset_network_header(skb);
1da177e4 LT	211
1da177e4 LT	212	switch (nb->dev->type) {
fddc5f3e JP	213	case ARPHRD_X25:
	214	dptr = skb_push(skb, 1);
	215	*dptr = X25_IFACE_DATA;
	216	break;
1da177e4	217
29c36262	218	#if IS_ENABLED(CONFIG_LLC)
fddc5f3e JP	219	case ARPHRD_ETHER:
	220	kfree_skb(skb);
	221	return;
1da177e4	222	#endif
fddc5f3e JP	223	default:
	224	kfree_skb(skb);
	225	return;
1da177e4 LT	226	}
	227
	228	skb->protocol = htons(ETH_P_X25);
	229	skb->dev = nb->dev;
	230
	231	dev_queue_xmit(skb);
	232	}