Release 4.15 net/l2tp/l2tp_eth.c

/*
 * L2TPv3 ethernet pseudowire driver
 *
 * Copyright (c) 2008,2009,2010 Katalix Systems Ltd
 *
 *      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.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/hash.h>
#include <linux/l2tp.h>
#include <linux/in.h>
#include <linux/etherdevice.h>
#include <linux/spinlock.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/tcp_states.h>
#include <net/protocol.h>
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>

#include "l2tp_core.h"

/* Default device name. May be overridden by name specified by user */

#define L2TP_ETH_DEV_NAME	"l2tpeth%d"

/* via netdev_priv() */

struct l2tp_eth {
	
struct l2tp_session	*session;
	
atomic_long_t		tx_bytes;
	
atomic_long_t		tx_packets;
	
atomic_long_t		tx_dropped;
	
atomic_long_t		rx_bytes;
	
atomic_long_t		rx_packets;
	
atomic_long_t		rx_errors;
};

/* via l2tp_session_priv() */

struct l2tp_eth_sess {
	
struct net_device __rcu *dev;
};




static int l2tp_eth_dev_init(struct net_device *dev)
{
	eth_hw_addr_random(dev);
	eth_broadcast_addr(dev->broadcast);
	netdev_lockdep_set_classes(dev);

	return 0;
}

Contributors
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James Chapman
24
77.42%
1
16.67%
Eric Dumazet
5
16.13%
3
50.00%
Joe Perches
1
3.23%
1
16.67%
Danny Kukawka
1
3.23%
1
16.67%
Total
31
100.00%
6
100.00%



static void l2tp_eth_dev_uninit(struct net_device *dev)
{
	struct l2tp_eth *priv = netdev_priv(dev);
	struct l2tp_eth_sess *spriv;

	spriv = l2tp_session_priv(priv->session);
	RCU_INIT_POINTER(spriv->dev, NULL);
	/* No need for synchronize_net() here. We're called by
         * unregister_netdev*(), which does the synchronisation for us.
         */
}

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30
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1
50.00%
James Chapman
15
33.33%
1
50.00%
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45
100.00%
2
100.00%



static int l2tp_eth_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct l2tp_eth *priv = netdev_priv(dev);
	struct l2tp_session *session = priv->session;
	unsigned int len = skb->len;
	int ret = l2tp_xmit_skb(session, skb, session->hdr_len);

	if (likely(ret == NET_XMIT_SUCCESS)) {
		atomic_long_add(len, &priv->tx_bytes);
		atomic_long_inc(&priv->tx_packets);
	} else {
		atomic_long_inc(&priv->tx_dropped);
	}
	return NETDEV_TX_OK;
}

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Eric Dumazet
56
56.00%
3
75.00%
James Chapman
44
44.00%
1
25.00%
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100
100.00%
4
100.00%



static void l2tp_eth_get_stats64(struct net_device *dev,
				 struct rtnl_link_stats64 *stats)
{
	struct l2tp_eth *priv = netdev_priv(dev);

	stats->tx_bytes   = (unsigned long) atomic_long_read(&priv->tx_bytes);
	stats->tx_packets = (unsigned long) atomic_long_read(&priv->tx_packets);
	stats->tx_dropped = (unsigned long) atomic_long_read(&priv->tx_dropped);
	stats->rx_bytes   = (unsigned long) atomic_long_read(&priv->rx_bytes);
	stats->rx_packets = (unsigned long) atomic_long_read(&priv->rx_packets);
	stats->rx_errors  = (unsigned long) atomic_long_read(&priv->rx_errors);

}

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Eric Dumazet
97
79.51%
2
50.00%
Dominik Heidler
24
19.67%
1
25.00%
Stephen Hemminger
1
0.82%
1
25.00%
Total
122
100.00%
4
100.00%


static const struct net_device_ops l2tp_eth_netdev_ops = {
	.ndo_init		= l2tp_eth_dev_init,
	.ndo_uninit		= l2tp_eth_dev_uninit,
	.ndo_start_xmit		= l2tp_eth_dev_xmit,
	.ndo_get_stats64	= l2tp_eth_get_stats64,
	.ndo_set_mac_address	= eth_mac_addr,
};


static struct device_type l2tpeth_type = {
	.name = "l2tpeth",
};



static void l2tp_eth_dev_setup(struct net_device *dev)
{
	SET_NETDEV_DEVTYPE(dev, &l2tpeth_type);
	ether_setup(dev);
	dev->priv_flags		&= ~IFF_TX_SKB_SHARING;
	dev->features		|= NETIF_F_LLTX;
	dev->netdev_ops		= &l2tp_eth_netdev_ops;
	dev->needs_free_netdev	= true;
}

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James Chapman
27
54.00%
1
20.00%
Guillaume Nault
8
16.00%
1
20.00%
Neil Horman
7
14.00%
1
20.00%
Eric Dumazet
6
12.00%
1
20.00%
David S. Miller
2
4.00%
1
20.00%
Total
50
100.00%
5
100.00%



static void l2tp_eth_dev_recv(struct l2tp_session *session, struct sk_buff *skb, int data_len)
{
	struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
	struct net_device *dev;
	struct l2tp_eth *priv;

	if (session->debug & L2TP_MSG_DATA) {
		unsigned int length;

		length = min(32u, skb->len);
		if (!pskb_may_pull(skb, length))
			goto error;

		pr_debug("%s: eth recv\n", session->name);
		print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, skb->data, length);
	}

	if (!pskb_may_pull(skb, ETH_HLEN))
		goto error;

	secpath_reset(skb);

	/* checksums verified by L2TP */
	skb->ip_summed = CHECKSUM_NONE;

	skb_dst_drop(skb);
	nf_reset(skb);

	rcu_read_lock();
	dev = rcu_dereference(spriv->dev);
	if (!dev)
		goto error_rcu;

	priv = netdev_priv(dev);
	if (dev_forward_skb(dev, skb) == NET_RX_SUCCESS) {
		atomic_long_inc(&priv->rx_packets);
		atomic_long_add(data_len, &priv->rx_bytes);
	} else {
		atomic_long_inc(&priv->rx_errors);
	}
	rcu_read_unlock();

	return;

error_rcu:
	rcu_read_unlock();
error:
	kfree_skb(skb);
}

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James Chapman
144
65.75%
1
20.00%
Guillaume Nault
35
15.98%
1
20.00%
Eric Dumazet
33
15.07%
2
40.00%
Joe Perches
7
3.20%
1
20.00%
Total
219
100.00%
5
100.00%



static void l2tp_eth_delete(struct l2tp_session *session)
{
	struct l2tp_eth_sess *spriv;
	struct net_device *dev;

	if (session) {
		spriv = l2tp_session_priv(session);

		rtnl_lock();
		dev = rtnl_dereference(spriv->dev);
		if (dev) {
			unregister_netdevice(dev);
			rtnl_unlock();
			module_put(THIS_MODULE);
		} else {
			rtnl_unlock();
		}
	}
}

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James Chapman
51
71.83%
1
33.33%
Guillaume Nault
15
21.13%
1
33.33%
Eric Dumazet
5
7.04%
1
33.33%
Total
71
100.00%
3
100.00%

#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)


static void l2tp_eth_show(struct seq_file *m, void *arg)
{
	struct l2tp_session *session = arg;
	struct l2tp_eth_sess *spriv = l2tp_session_priv(session);
	struct net_device *dev;

	rcu_read_lock();
	dev = rcu_dereference(spriv->dev);
	if (!dev) {
		rcu_read_unlock();
		return;
	}
	dev_hold(dev);
	rcu_read_unlock();

	seq_printf(m, "   interface %s\n", dev->name);

	dev_put(dev);
}
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James Chapman
50
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1
50.00%
Guillaume Nault
34
40.48%
1
50.00%
Total
84
100.00%
2
100.00%

#endif



static void l2tp_eth_adjust_mtu(struct l2tp_tunnel *tunnel,
				struct l2tp_session *session,
				struct net_device *dev)
{
	unsigned int overhead = 0;
	struct dst_entry *dst;
	u32 l3_overhead = 0;

	/* if the encap is UDP, account for UDP header size */
	if (tunnel->encap == L2TP_ENCAPTYPE_UDP) {
		overhead += sizeof(struct udphdr);
		dev->needed_headroom += sizeof(struct udphdr);
	}
	if (session->mtu != 0) {
		dev->mtu = session->mtu;
		dev->needed_headroom += session->hdr_len;
		return;
	}
	lock_sock(tunnel->sock);
	l3_overhead = kernel_sock_ip_overhead(tunnel->sock);
	release_sock(tunnel->sock);
	if (l3_overhead == 0) {
		/* L3 Overhead couldn't be identified, this could be
                 * because tunnel->sock was NULL or the socket's
                 * address family was not IPv4 or IPv6,
                 * dev mtu stays at 1500.
                 */
		return;
	}
	/* Adjust MTU, factor overhead - underlay L3, overlay L2 hdr
         * UDP overhead, if any, was already factored in above.
         */
	overhead += session->hdr_len + ETH_HLEN + l3_overhead;

	/* If PMTU discovery was enabled, use discovered MTU on L2TP device */
	dst = sk_dst_get(tunnel->sock);
	if (dst) {
		/* dst_mtu will use PMTU if found, else fallback to intf MTU */
		u32 pmtu = dst_mtu(dst);

		if (pmtu != 0)
			dev->mtu = pmtu;
		dst_release(dst);
	}
	session->mtu = dev->mtu - overhead;
	dev->mtu = session->mtu;
	dev->needed_headroom += session->hdr_len;
}

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static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
			   u32 session_id, u32 peer_session_id,
			   struct l2tp_session_cfg *cfg)
{
	unsigned char name_assign_type;
	struct net_device *dev;
	char name[IFNAMSIZ];
	struct l2tp_session *session;
	struct l2tp_eth *priv;
	struct l2tp_eth_sess *spriv;
	int rc;

	if (cfg->ifname) {
		strlcpy(name, cfg->ifname, IFNAMSIZ);
		name_assign_type = NET_NAME_USER;
	} else {
		strcpy(name, L2TP_ETH_DEV_NAME);
		name_assign_type = NET_NAME_ENUM;
	}

	session = l2tp_session_create(sizeof(*spriv), tunnel, session_id,
				      peer_session_id, cfg);
	if (IS_ERR(session)) {
		rc = PTR_ERR(session);
		goto err;
	}

	dev = alloc_netdev(sizeof(*priv), name, name_assign_type,
			   l2tp_eth_dev_setup);
	if (!dev) {
		rc = -ENOMEM;
		goto err_sess;
	}

	dev_net_set(dev, net);
	dev->min_mtu = 0;
	dev->max_mtu = ETH_MAX_MTU;
	l2tp_eth_adjust_mtu(tunnel, session, dev);

	priv = netdev_priv(dev);
	priv->session = session;

	session->recv_skb = l2tp_eth_dev_recv;
	session->session_close = l2tp_eth_delete;
#if IS_ENABLED(CONFIG_L2TP_DEBUGFS)
	session->show = l2tp_eth_show;
#endif

	spriv = l2tp_session_priv(session);

	l2tp_session_inc_refcount(session);

	rtnl_lock();

	/* Register both device and session while holding the rtnl lock. This
         * ensures that l2tp_eth_delete() will see that there's a device to
         * unregister, even if it happened to run before we assign spriv->dev.
         */
	rc = l2tp_session_register(session, tunnel);
	if (rc < 0) {
		rtnl_unlock();
		goto err_sess_dev;
	}

	rc = register_netdevice(dev);
	if (rc < 0) {
		rtnl_unlock();
		l2tp_session_delete(session);
		l2tp_session_dec_refcount(session);
		free_netdev(dev);

		return rc;
	}

	strlcpy(session->ifname, dev->name, IFNAMSIZ);
	rcu_assign_pointer(spriv->dev, dev);

	rtnl_unlock();

	l2tp_session_dec_refcount(session);

	__module_get(THIS_MODULE);

	return 0;

err_sess_dev:
	l2tp_session_dec_refcount(session);
	free_netdev(dev);
err_sess:
	kfree(session);
err:
	return rc;
}


Contributors
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James Chapman
228
61.46%
2
15.38%
Guillaume Nault
113
30.46%
5
38.46%
Jarod Wilson
12
3.23%
1
7.69%
R. Parameswaran
9
2.43%
1
7.69%
David S. Miller
4
1.08%
1
7.69%
Eric Dumazet
3
0.81%
1
7.69%
Tom Gundersen
1
0.27%
1
7.69%
Javier Martinez Canillas
1
0.27%
1
7.69%
Total
371
100.00%
13
100.00%


static const struct l2tp_nl_cmd_ops l2tp_eth_nl_cmd_ops = {
	.session_create	= l2tp_eth_create,
	.session_delete	= l2tp_session_delete,
};




static int __init l2tp_eth_init(void)
{
	int err = 0;

	err = l2tp_nl_register_ops(L2TP_PWTYPE_ETH, &l2tp_eth_nl_cmd_ops);
	if (err)
		goto err;

	pr_info("L2TP ethernet pseudowire support (L2TPv3)\n");

	return 0;

err:
	return err;
}

Contributors
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James Chapman
42
95.45%
1
33.33%
Joe Perches
1
2.27%
1
33.33%
Guillaume Nault
1
2.27%
1
33.33%
Total
44
100.00%
3
100.00%



static void __exit l2tp_eth_exit(void)
{
	l2tp_nl_unregister_ops(L2TP_PWTYPE_ETH);
}

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1
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14
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1
100.00%


module_init(l2tp_eth_init);

module_exit(l2tp_eth_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
MODULE_DESCRIPTION("L2TP ethernet pseudowire driver");
MODULE_VERSION("1.0");
MODULE_ALIAS_L2TP_PWTYPE(5);
Overall Contributors
Person
Tokens
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Commits
CommitProp
James Chapman
800
50.47%
2
6.06%
Guillaume Nault
249
15.71%
7
21.21%
Eric Dumazet
228
14.38%
8
24.24%
R. Parameswaran
223
14.07%
2
6.06%
Dominik Heidler
24
1.51%
1
3.03%
Joe Perches
16
1.01%
2
6.06%
Jarod Wilson
12
0.76%
1
3.03%
David S. Miller
10
0.63%
2
6.06%
Neil Horman
7
0.44%
1
3.03%
Stephen Hemminger
6
0.38%
2
6.06%
Alexander Couzens
5
0.32%
1
3.03%
Javier Martinez Canillas
2
0.13%
1
3.03%
Julia Lawall
1
0.06%
1
3.03%
Danny Kukawka
1
0.06%
1
3.03%
Tom Gundersen
1
0.06%
1
3.03%
Total
1585
100.00%
33
100.00%
Directory: net/l2tp

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