veth.c revision 5517750f058edd111bcabe5e116056cc63b1f39c 
1/*
2 *  drivers/net/veth.c
3 *
4 *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
5 *
6 * Author: Pavel Emelianov <xemul@openvz.org>
7 * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
8 *
9 */
10
11#include <linux/netdevice.h>
12#include <linux/slab.h>
13#include <linux/ethtool.h>
14#include <linux/etherdevice.h>
15#include <linux/u64_stats_sync.h>
16
17#include <net/rtnetlink.h>
18#include <net/dst.h>
19#include <net/xfrm.h>
20#include <linux/veth.h>
21#include <linux/module.h>
22
23#define DRV_NAME	"veth"
24#define DRV_VERSION	"1.0"
25
26#define MIN_MTU 68		/* Min L3 MTU */
27#define MAX_MTU 65535		/* Max L3 MTU (arbitrary) */
28
29struct pcpu_vstats {
30	u64			packets;
31	u64			bytes;
32	struct u64_stats_sync	syncp;
33};
34
35struct veth_priv {
36	struct net_device __rcu	*peer;
37	atomic64_t		dropped;
38};
39
40/*
41 * ethtool interface
42 */
43
44static struct {
45	const char string[ETH_GSTRING_LEN];
46} ethtool_stats_keys[] = {
47	{ "peer_ifindex" },
48};
49
50static int veth_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
51{
52	cmd->supported		= 0;
53	cmd->advertising	= 0;
54	ethtool_cmd_speed_set(cmd, SPEED_10000);
55	cmd->duplex		= DUPLEX_FULL;
56	cmd->port		= PORT_TP;
57	cmd->phy_address	= 0;
58	cmd->transceiver	= XCVR_INTERNAL;
59	cmd->autoneg		= AUTONEG_DISABLE;
60	cmd->maxtxpkt		= 0;
61	cmd->maxrxpkt		= 0;
62	return 0;
63}
64
65static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
66{
67	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
68	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
69}
70
71static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
72{
73	switch(stringset) {
74	case ETH_SS_STATS:
75		memcpy(buf, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
76		break;
77	}
78}
79
80static int veth_get_sset_count(struct net_device *dev, int sset)
81{
82	switch (sset) {
83	case ETH_SS_STATS:
84		return ARRAY_SIZE(ethtool_stats_keys);
85	default:
86		return -EOPNOTSUPP;
87	}
88}
89
90static void veth_get_ethtool_stats(struct net_device *dev,
91		struct ethtool_stats *stats, u64 *data)
92{
93	struct veth_priv *priv = netdev_priv(dev);
94	struct net_device *peer = rtnl_dereference(priv->peer);
95
96	data[0] = peer ? peer->ifindex : 0;
97}
98
99static const struct ethtool_ops veth_ethtool_ops = {
100	.get_settings		= veth_get_settings,
101	.get_drvinfo		= veth_get_drvinfo,
102	.get_link		= ethtool_op_get_link,
103	.get_strings		= veth_get_strings,
104	.get_sset_count		= veth_get_sset_count,
105	.get_ethtool_stats	= veth_get_ethtool_stats,
106};
107
108static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
109{
110	struct veth_priv *priv = netdev_priv(dev);
111	struct net_device *rcv;
112	int length = skb->len;
113
114	rcu_read_lock();
115	rcv = rcu_dereference(priv->peer);
116	if (unlikely(!rcv)) {
117		kfree_skb(skb);
118		goto drop;
119	}
120	/* don't change ip_summed == CHECKSUM_PARTIAL, as that
121	 * will cause bad checksum on forwarded packets
122	 */
123	if (skb->ip_summed == CHECKSUM_NONE &&
124	    rcv->features & NETIF_F_RXCSUM)
125		skb->ip_summed = CHECKSUM_UNNECESSARY;
126
127	if (likely(dev_forward_skb(rcv, skb) == NET_RX_SUCCESS)) {
128		struct pcpu_vstats *stats = this_cpu_ptr(dev->vstats);
129
130		u64_stats_update_begin(&stats->syncp);
131		stats->bytes += length;
132		stats->packets++;
133		u64_stats_update_end(&stats->syncp);
134	} else {
135drop:
136		atomic64_inc(&priv->dropped);
137	}
138	rcu_read_unlock();
139	return NETDEV_TX_OK;
140}
141
142/*
143 * general routines
144 */
145
146static u64 veth_stats_one(struct pcpu_vstats *result, struct net_device *dev)
147{
148	struct veth_priv *priv = netdev_priv(dev);
149	int cpu;
150
151	result->packets = 0;
152	result->bytes = 0;
153	for_each_possible_cpu(cpu) {
154		struct pcpu_vstats *stats = per_cpu_ptr(dev->vstats, cpu);
155		u64 packets, bytes;
156		unsigned int start;
157
158		do {
159			start = u64_stats_fetch_begin_irq(&stats->syncp);
160			packets = stats->packets;
161			bytes = stats->bytes;
162		} while (u64_stats_fetch_retry_irq(&stats->syncp, start));
163		result->packets += packets;
164		result->bytes += bytes;
165	}
166	return atomic64_read(&priv->dropped);
167}
168
169static struct rtnl_link_stats64 *veth_get_stats64(struct net_device *dev,
170						  struct rtnl_link_stats64 *tot)
171{
172	struct veth_priv *priv = netdev_priv(dev);
173	struct net_device *peer;
174	struct pcpu_vstats one;
175
176	tot->tx_dropped = veth_stats_one(&one, dev);
177	tot->tx_bytes = one.bytes;
178	tot->tx_packets = one.packets;
179
180	rcu_read_lock();
181	peer = rcu_dereference(priv->peer);
182	if (peer) {
183		tot->rx_dropped = veth_stats_one(&one, peer);
184		tot->rx_bytes = one.bytes;
185		tot->rx_packets = one.packets;
186	}
187	rcu_read_unlock();
188
189	return tot;
190}
191
192/* fake multicast ability */
193static void veth_set_multicast_list(struct net_device *dev)
194{
195}
196
197static int veth_open(struct net_device *dev)
198{
199	struct veth_priv *priv = netdev_priv(dev);
200	struct net_device *peer = rtnl_dereference(priv->peer);
201
202	if (!peer)
203		return -ENOTCONN;
204
205	if (peer->flags & IFF_UP) {
206		netif_carrier_on(dev);
207		netif_carrier_on(peer);
208	}
209	return 0;
210}
211
212static int veth_close(struct net_device *dev)
213{
214	struct veth_priv *priv = netdev_priv(dev);
215	struct net_device *peer = rtnl_dereference(priv->peer);
216
217	netif_carrier_off(dev);
218	if (peer)
219		netif_carrier_off(peer);
220
221	return 0;
222}
223
224static int is_valid_veth_mtu(int new_mtu)
225{
226	return new_mtu >= MIN_MTU && new_mtu <= MAX_MTU;
227}
228
229static int veth_change_mtu(struct net_device *dev, int new_mtu)
230{
231	if (!is_valid_veth_mtu(new_mtu))
232		return -EINVAL;
233	dev->mtu = new_mtu;
234	return 0;
235}
236
237static int veth_dev_init(struct net_device *dev)
238{
239	dev->vstats = netdev_alloc_pcpu_stats(struct pcpu_vstats);
240	if (!dev->vstats)
241		return -ENOMEM;
242	return 0;
243}
244
245static void veth_dev_free(struct net_device *dev)
246{
247	free_percpu(dev->vstats);
248	free_netdev(dev);
249}
250
251#ifdef CONFIG_NET_POLL_CONTROLLER
252static void veth_poll_controller(struct net_device *dev)
253{
254	/* veth only receives frames when its peer sends one
255	 * Since it's a synchronous operation, we are guaranteed
256	 * never to have pending data when we poll for it so
257	 * there is nothing to do here.
258	 *
259	 * We need this though so netpoll recognizes us as an interface that
260	 * supports polling, which enables bridge devices in virt setups to
261	 * still use netconsole
262	 */
263}
264#endif	/* CONFIG_NET_POLL_CONTROLLER */
265
266static const struct net_device_ops veth_netdev_ops = {
267	.ndo_init            = veth_dev_init,
268	.ndo_open            = veth_open,
269	.ndo_stop            = veth_close,
270	.ndo_start_xmit      = veth_xmit,
271	.ndo_change_mtu      = veth_change_mtu,
272	.ndo_get_stats64     = veth_get_stats64,
273	.ndo_set_rx_mode     = veth_set_multicast_list,
274	.ndo_set_mac_address = eth_mac_addr,
275#ifdef CONFIG_NET_POLL_CONTROLLER
276	.ndo_poll_controller	= veth_poll_controller,
277#endif
278};
279
280#define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO |    \
281		       NETIF_F_HW_CSUM | NETIF_F_RXCSUM | NETIF_F_HIGHDMA | \
282		       NETIF_F_GSO_GRE | NETIF_F_GSO_UDP_TUNNEL |	    \
283		       NETIF_F_GSO_IPIP | NETIF_F_GSO_SIT | NETIF_F_UFO	|   \
284		       NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
285		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
286
287static void veth_setup(struct net_device *dev)
288{
289	ether_setup(dev);
290
291	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
292	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
293
294	dev->netdev_ops = &veth_netdev_ops;
295	dev->ethtool_ops = &veth_ethtool_ops;
296	dev->features |= NETIF_F_LLTX;
297	dev->features |= VETH_FEATURES;
298	dev->vlan_features = dev->features &
299			     ~(NETIF_F_HW_VLAN_CTAG_TX |
300			       NETIF_F_HW_VLAN_STAG_TX |
301			       NETIF_F_HW_VLAN_CTAG_RX |
302			       NETIF_F_HW_VLAN_STAG_RX);
303	dev->destructor = veth_dev_free;
304
305	dev->hw_features = VETH_FEATURES;
306	dev->hw_enc_features = VETH_FEATURES;
307}
308
309/*
310 * netlink interface
311 */
312
313static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
314{
315	if (tb[IFLA_ADDRESS]) {
316		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
317			return -EINVAL;
318		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
319			return -EADDRNOTAVAIL;
320	}
321	if (tb[IFLA_MTU]) {
322		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
323			return -EINVAL;
324	}
325	return 0;
326}
327
328static struct rtnl_link_ops veth_link_ops;
329
330static int veth_newlink(struct net *src_net, struct net_device *dev,
331			 struct nlattr *tb[], struct nlattr *data[])
332{
333	int err;
334	struct net_device *peer;
335	struct veth_priv *priv;
336	char ifname[IFNAMSIZ];
337	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
338	unsigned char name_assign_type;
339	struct ifinfomsg *ifmp;
340	struct net *net;
341
342	/*
343	 * create and register peer first
344	 */
345	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
346		struct nlattr *nla_peer;
347
348		nla_peer = data[VETH_INFO_PEER];
349		ifmp = nla_data(nla_peer);
350		err = rtnl_nla_parse_ifla(peer_tb,
351					  nla_data(nla_peer) + sizeof(struct ifinfomsg),
352					  nla_len(nla_peer) - sizeof(struct ifinfomsg));
353		if (err < 0)
354			return err;
355
356		err = veth_validate(peer_tb, NULL);
357		if (err < 0)
358			return err;
359
360		tbp = peer_tb;
361	} else {
362		ifmp = NULL;
363		tbp = tb;
364	}
365
366	if (tbp[IFLA_IFNAME]) {
367		nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
368		name_assign_type = NET_NAME_USER;
369	} else {
370		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
371		name_assign_type = NET_NAME_ENUM;
372	}
373
374	net = rtnl_link_get_net(src_net, tbp);
375	if (IS_ERR(net))
376		return PTR_ERR(net);
377
378	peer = rtnl_create_link(net, ifname, name_assign_type,
379				&veth_link_ops, tbp);
380	if (IS_ERR(peer)) {
381		put_net(net);
382		return PTR_ERR(peer);
383	}
384
385	if (tbp[IFLA_ADDRESS] == NULL)
386		eth_hw_addr_random(peer);
387
388	if (ifmp && (dev->ifindex != 0))
389		peer->ifindex = ifmp->ifi_index;
390
391	err = register_netdevice(peer);
392	put_net(net);
393	net = NULL;
394	if (err < 0)
395		goto err_register_peer;
396
397	netif_carrier_off(peer);
398
399	err = rtnl_configure_link(peer, ifmp);
400	if (err < 0)
401		goto err_configure_peer;
402
403	/*
404	 * register dev last
405	 *
406	 * note, that since we've registered new device the dev's name
407	 * should be re-allocated
408	 */
409
410	if (tb[IFLA_ADDRESS] == NULL)
411		eth_hw_addr_random(dev);
412
413	if (tb[IFLA_IFNAME])
414		nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
415	else
416		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
417
418	err = register_netdevice(dev);
419	if (err < 0)
420		goto err_register_dev;
421
422	netif_carrier_off(dev);
423
424	/*
425	 * tie the deviced together
426	 */
427
428	priv = netdev_priv(dev);
429	rcu_assign_pointer(priv->peer, peer);
430
431	priv = netdev_priv(peer);
432	rcu_assign_pointer(priv->peer, dev);
433	return 0;
434
435err_register_dev:
436	/* nothing to do */
437err_configure_peer:
438	unregister_netdevice(peer);
439	return err;
440
441err_register_peer:
442	free_netdev(peer);
443	return err;
444}
445
446static void veth_dellink(struct net_device *dev, struct list_head *head)
447{
448	struct veth_priv *priv;
449	struct net_device *peer;
450
451	priv = netdev_priv(dev);
452	peer = rtnl_dereference(priv->peer);
453
454	/* Note : dellink() is called from default_device_exit_batch(),
455	 * before a rcu_synchronize() point. The devices are guaranteed
456	 * not being freed before one RCU grace period.
457	 */
458	RCU_INIT_POINTER(priv->peer, NULL);
459	unregister_netdevice_queue(dev, head);
460
461	if (peer) {
462		priv = netdev_priv(peer);
463		RCU_INIT_POINTER(priv->peer, NULL);
464		unregister_netdevice_queue(peer, head);
465	}
466}
467
468static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
469	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
470};
471
472static struct rtnl_link_ops veth_link_ops = {
473	.kind		= DRV_NAME,
474	.priv_size	= sizeof(struct veth_priv),
475	.setup		= veth_setup,
476	.validate	= veth_validate,
477	.newlink	= veth_newlink,
478	.dellink	= veth_dellink,
479	.policy		= veth_policy,
480	.maxtype	= VETH_INFO_MAX,
481};
482
483/*
484 * init/fini
485 */
486
487static __init int veth_init(void)
488{
489	return rtnl_link_register(&veth_link_ops);
490}
491
492static __exit void veth_exit(void)
493{
494	rtnl_link_unregister(&veth_link_ops);
495}
496
497module_init(veth_init);
498module_exit(veth_exit);
499
500MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
501MODULE_LICENSE("GPL v2");
502MODULE_ALIAS_RTNL_LINK(DRV_NAME);
503