Release 4.15 net/802/psnap.c

/*
 *      SNAP data link layer. Derived from 802.2
 *
 *              Alan Cox <alan@lxorguk.ukuu.org.uk>,
 *              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 <linux/slab.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>
#include <linux/rculist.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(const unsigned char *desc)
{
	struct datalink_proto *proto = NULL, *p;

	list_for_each_entry_rcu(p, &snap_list, node) {
		if (!memcmp(p->type, desc, 5)) {
			proto = p;
			break;
		}
	}
	return proto;
}

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Linus Torvalds (pre-git)
32
55.17%
1
20.00%
Arnaldo Carvalho de Melo
21
36.21%
2
40.00%
Paul E. McKenney
4
6.90%
1
20.00%
Stephen Hemminger
1
1.72%
1
20.00%
Total
58
100.00%
5
100.00%

/*
 *      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 = cpu_to_be16(ETH_P_SNAP),
        };

	if (unlikely(!pskb_may_pull(skb, 5)))
		goto drop;

	rcu_read_lock();
	proto = find_snap_client(skb_transport_header(skb));
	if (proto) {
		/* Pass the frame on. */
		skb->transport_header += 5;
		skb_pull_rcsum(skb, 5);
		rc = proto->rcvfunc(skb, dev, &snap_packet_type, orig_dev);
	}
	rcu_read_unlock();

	if (unlikely(!proto))
		goto drop;

out:
	return rc;

drop:
	kfree_skb(skb);
	goto out;
}

Contributors
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Arnaldo Carvalho de Melo
47
32.41%
6
42.86%
Herbert Xu
40
27.59%
2
14.29%
Linus Torvalds (pre-git)
37
25.52%
3
21.43%
Stephen Hemminger
13
8.97%
1
7.14%
David S. Miller
7
4.83%
1
7.14%
Harvey Harrison
1
0.69%
1
7.14%
Total
145
100.00%
14
100.00%

/*
 *      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;
}

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62.96%
3
60.00%
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20
37.04%
2
40.00%
Total
54
100.00%
5
100.00%

/*
 *      Set up the SNAP layer
 */

EXPORT_SYMBOL(register_snap_client);

EXPORT_SYMBOL(unregister_snap_client);


static const char snap_err_msg[] __initconst =
	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 -EBUSY;
	}

	return 0;
}

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3
37.50%
Arnaldo Carvalho de Melo
8
21.62%
4
50.00%
Stephen Hemminger
6
16.22%
1
12.50%
Total
37
100.00%
8
100.00%


module_init(snap_init);



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

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module_exit(snap_exit);


/*
 *      Register SNAP clients. We don't yet use this for IP.
 */


struct datalink_proto *register_snap_client(const 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);

	return proto;
}

Contributors
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Linus Torvalds (pre-git)
97
73.48%
2
28.57%
Arnaldo Carvalho de Melo
23
17.42%
2
28.57%
Stephen Hemminger
8
6.06%
2
28.57%
David S. Miller
4
3.03%
1
14.29%
Total
132
100.00%
7
100.00%

/*
 *      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);
}

Contributors
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Linus Torvalds (pre-git)
20
52.63%
1
33.33%
Stephen Hemminger
12
31.58%
1
33.33%
Arnaldo Carvalho de Melo
6
15.79%
1
33.33%
Total
38
100.00%
3
100.00%

MODULE_LICENSE("GPL");
Overall Contributors
Person
Tokens
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Commits
CommitProp
Linus Torvalds (pre-git)
294
51.49%
12
35.29%
Arnaldo Carvalho de Melo
165
28.90%
10
29.41%
Stephen Hemminger
45
7.88%
3
8.82%
Herbert Xu
40
7.01%
2
5.88%
David S. Miller
11
1.93%
1
2.94%
Thomas Gleixner
4
0.70%
1
2.94%
Paul E. McKenney
4
0.70%
1
2.94%
Franck Bui-Huu
3
0.53%
1
2.94%
Tejun Heo
3
0.53%
1
2.94%
Harvey Harrison
1
0.18%
1
2.94%
Alan Cox
1
0.18%
1
2.94%
Total
571
100.00%
34
100.00%
Directory: net/802

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