[deliverable/linux.git] / net / 802 / psnap.c

/*
 *	SNAP data link layer. Derived from 802.2
 *
 *		Alan Cox <Alan.Cox@linux.org>,
 *		from the 802.2 layer by Greg Page.
 *		Merged in additions from Greg Page's psnap.c.
 *
 *		This program 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.
 */

#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/datalink.h>
#include <net/llc.h>
#include <net/psnap.h>
#include <linux/mm.h>
#include <linux/in.h>
#include <linux/init.h>

static LIST_HEAD(snap_list);
static DEFINE_SPINLOCK(snap_lock);
static struct llc_sap *snap_sap;

/*
 *	Find a snap client by matching the 5 bytes.
 */
static struct datalink_proto *find_snap_client(unsigned char *desc)
{
	struct list_head *entry;
	struct datalink_proto *proto = NULL, *p;

	list_for_each_rcu(entry, &snap_list) {
		p = list_entry(entry, struct datalink_proto, node);
		if (!memcmp(p->type, desc, 5)) {
			proto = p;
			break;
		}
	}
	return proto;
}

/*
 *	A SNAP packet has arrived
 */
static int snap_rcv(struct sk_buff *skb, struct net_device *dev,
		    struct packet_type *pt, struct net_device *orig_dev)
{
	int rc = 1;
	struct datalink_proto *proto;
	static struct packet_type snap_packet_type = {
		.type = __constant_htons(ETH_P_SNAP),
	};

	rcu_read_lock();
	proto = find_snap_client(skb->h.raw);
	if (proto) {
		/* Pass the frame on. */
		u8 *hdr = skb->data;
		skb->h.raw  += 5;
		skb_pull_rcsum(skb, 5);
		rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev);
	} else {
		skb->sk = NULL;
		kfree_skb(skb);
		rc = 1;
	}

	rcu_read_unlock();
	return rc;
}

/*
 *	Put a SNAP header on a frame and pass to 802.2
 */
static int snap_request(struct datalink_proto *dl,
			struct sk_buff *skb, u8 *dest)
{
	memcpy(skb_push(skb, 5), dl->type, 5);
	llc_build_and_send_ui_pkt(snap_sap, skb, dest, snap_sap->laddr.lsap);
	return 0;
}

/*
 *	Set up the SNAP layer
 */
EXPORT_SYMBOL(register_snap_client);
EXPORT_SYMBOL(unregister_snap_client);

static char snap_err_msg[] __initdata =
	KERN_CRIT "SNAP - unable to register with 802.2\n";

static int __init snap_init(void)
{
	snap_sap = llc_sap_open(0xAA, snap_rcv);

	if (!snap_sap)
		printk(snap_err_msg);

	return 0;
}

module_init(snap_init);

static void __exit snap_exit(void)
{
	llc_sap_put(snap_sap);
}

module_exit(snap_exit);


/*
 *	Register SNAP clients. We don't yet use this for IP.
 */
struct datalink_proto *register_snap_client(unsigned char *desc,
					    int (*rcvfunc)(struct sk_buff *,
						    	   struct net_device *,
							   struct packet_type *,
							   struct net_device *))
{
	struct datalink_proto *proto = NULL;

	spin_lock_bh(&snap_lock);

	if (find_snap_client(desc))
		goto out;

	proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
	if (proto) {
		memcpy(proto->type, desc,5);
		proto->rcvfunc		= rcvfunc;
		proto->header_length	= 5 + 3; /* snap + 802.2 */
		proto->request		= snap_request;
		list_add_rcu(&proto->node, &snap_list);
	}
out:
	spin_unlock_bh(&snap_lock);

	synchronize_net();
	return proto;
}

/*
 *	Unregister SNAP clients. Protocols no longer want to play with us ...
 */
void unregister_snap_client(struct datalink_proto *proto)
{
	spin_lock_bh(&snap_lock);
	list_del_rcu(&proto->node);
	spin_unlock_bh(&snap_lock);

	synchronize_net();

	kfree(proto);
}

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* SNAP data link layer. Derived from 802.2
	3	*
	4	* Alan Cox <Alan.Cox@linux.org>,
	5	* from the 802.2 layer by Greg Page.
	6	* Merged in additions from Greg Page's psnap.c.
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13
	14	#include <linux/module.h>
	15	#include <linux/netdevice.h>
	16	#include <linux/skbuff.h>
	17	#include <net/datalink.h>
	18	#include <net/llc.h>
	19	#include <net/psnap.h>
	20	#include <linux/mm.h>
	21	#include <linux/in.h>
	22	#include <linux/init.h>
	23
	24	static LIST_HEAD(snap_list);
	25	static DEFINE_SPINLOCK(snap_lock);
	26	static struct llc_sap *snap_sap;
	27
	28	/*
	29	* Find a snap client by matching the 5 bytes.
	30	*/
	31	static struct datalink_proto find_snap_client(unsigned char desc)
	32	{
	33	struct list_head *entry;
	34	struct datalink_proto proto = NULL, p;
	35
	36	list_for_each_rcu(entry, &snap_list) {
	37	p = list_entry(entry, struct datalink_proto, node);
	38	if (!memcmp(p->type, desc, 5)) {
	39	proto = p;
	40	break;
	41	}
	42	}
	43	return proto;
	44	}
	45
	46	/*
	47	* A SNAP packet has arrived
	48	*/
	49	static int snap_rcv(struct sk_buff skb, struct net_device dev,
f2ccd8fa	50	struct packet_type pt, struct net_device orig_dev)
1da177e4 LT	51	{
	52	int rc = 1;
	53	struct datalink_proto *proto;
	54	static struct packet_type snap_packet_type = {
	55	.type = __constant_htons(ETH_P_SNAP),
	56	};
	57
	58	rcu_read_lock();
	59	proto = find_snap_client(skb->h.raw);
	60	if (proto) {
	61	/* Pass the frame on. */
42c5e15f	62	u8 *hdr = skb->data;
1da177e4	63	skb->h.raw += 5;
cbb042f9	64	skb_pull_rcsum(skb, 5);
f2ccd8fa	65	rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev);
1da177e4 LT	66	} else {
	67	skb->sk = NULL;
	68	kfree_skb(skb);
	69	rc = 1;
	70	}
	71
	72	rcu_read_unlock();
	73	return rc;
	74	}
	75
	76	/*
	77	* Put a SNAP header on a frame and pass to 802.2
	78	*/
	79	static int snap_request(struct datalink_proto *dl,
	80	struct sk_buff skb, u8 dest)
	81	{
	82	memcpy(skb_push(skb, 5), dl->type, 5);
	83	llc_build_and_send_ui_pkt(snap_sap, skb, dest, snap_sap->laddr.lsap);
	84	return 0;
	85	}
	86
	87	/*
	88	* Set up the SNAP layer
	89	*/
	90	EXPORT_SYMBOL(register_snap_client);
	91	EXPORT_SYMBOL(unregister_snap_client);
	92
	93	static char snap_err_msg[] __initdata =
	94	KERN_CRIT "SNAP - unable to register with 802.2\n";
	95
	96	static int __init snap_init(void)
	97	{
	98	snap_sap = llc_sap_open(0xAA, snap_rcv);
	99
	100	if (!snap_sap)
	101	printk(snap_err_msg);
	102
	103	return 0;
	104	}
	105
	106	module_init(snap_init);
	107
	108	static void __exit snap_exit(void)
	109	{
6e2144b7	110	llc_sap_put(snap_sap);
1da177e4 LT	111	}
	112
	113	module_exit(snap_exit);
	114
	115
	116	/*
	117	* Register SNAP clients. We don't yet use this for IP.
	118	*/
	119	struct datalink_proto register_snap_client(unsigned char desc,
	120	int (rcvfunc)(struct sk_buff ,
	121	struct net_device *,
f2ccd8fa DM	122	struct packet_type *,
f2ccd8fa DM	123	struct net_device *))
1da177e4 LT	124	{
	125	struct datalink_proto *proto = NULL;
	126
	127	spin_lock_bh(&snap_lock);
	128
	129	if (find_snap_client(desc))
	130	goto out;
	131
	132	proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
	133	if (proto) {
	134	memcpy(proto->type, desc,5);
	135	proto->rcvfunc = rcvfunc;
	136	proto->header_length = 5 + 3; /* snap + 802.2 */
	137	proto->request = snap_request;
	138	list_add_rcu(&proto->node, &snap_list);
	139	}
	140	out:
	141	spin_unlock_bh(&snap_lock);
	142
	143	synchronize_net();
	144	return proto;
	145	}
	146
	147	/*
	148	* Unregister SNAP clients. Protocols no longer want to play with us ...
	149	*/
	150	void unregister_snap_client(struct datalink_proto *proto)
	151	{
	152	spin_lock_bh(&snap_lock);
	153	list_del_rcu(&proto->node);
	154	spin_unlock_bh(&snap_lock);
	155
	156	synchronize_net();
	157
	158	kfree(proto);
	159	}
	160
	161	MODULE_LICENSE("GPL");