xref: /openbmc/linux/drivers/net/veth.c (revision 9cfc5c90) 
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 
29 struct pcpu_vstats {
30 	u64			packets;
31 	u64			bytes;
32 	struct u64_stats_sync	syncp;
33 };
34 
35 struct veth_priv {
36 	struct net_device __rcu	*peer;
37 	atomic64_t		dropped;
38 };
39 
40 /*
41  * ethtool interface
42  */
43 
44 static struct {
45 	const char string[ETH_GSTRING_LEN];
46 } ethtool_stats_keys[] = {
47 	{ "peer_ifindex" },
48 };
49 
50 static 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 
65 static 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 
71 static 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 
80 static 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 
90 static 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 
99 static 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 
108 static 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 {
135 drop:
136 		atomic64_inc(&priv->dropped);
137 	}
138 	rcu_read_unlock();
139 	return NETDEV_TX_OK;
140 }
141 
142 /*
143  * general routines
144  */
145 
146 static 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 
169 static 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 */
193 static void veth_set_multicast_list(struct net_device *dev)
194 {
195 }
196 
197 static 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 
212 static 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 
224 static int is_valid_veth_mtu(int new_mtu)
225 {
226 	return new_mtu >= MIN_MTU && new_mtu <= MAX_MTU;
227 }
228 
229 static 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 
237 static 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 
245 static 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
252 static 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 
266 static int veth_get_iflink(const struct net_device *dev)
267 {
268 	struct veth_priv *priv = netdev_priv(dev);
269 	struct net_device *peer;
270 	int iflink;
271 
272 	rcu_read_lock();
273 	peer = rcu_dereference(priv->peer);
274 	iflink = peer ? peer->ifindex : 0;
275 	rcu_read_unlock();
276 
277 	return iflink;
278 }
279 
280 static const struct net_device_ops veth_netdev_ops = {
281 	.ndo_init            = veth_dev_init,
282 	.ndo_open            = veth_open,
283 	.ndo_stop            = veth_close,
284 	.ndo_start_xmit      = veth_xmit,
285 	.ndo_change_mtu      = veth_change_mtu,
286 	.ndo_get_stats64     = veth_get_stats64,
287 	.ndo_set_rx_mode     = veth_set_multicast_list,
288 	.ndo_set_mac_address = eth_mac_addr,
289 #ifdef CONFIG_NET_POLL_CONTROLLER
290 	.ndo_poll_controller	= veth_poll_controller,
291 #endif
292 	.ndo_get_iflink		= veth_get_iflink,
293 	.ndo_features_check	= passthru_features_check,
294 };
295 
296 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO |    \
297 		       NETIF_F_HW_CSUM | NETIF_F_RXCSUM | NETIF_F_HIGHDMA | \
298 		       NETIF_F_GSO_GRE | NETIF_F_GSO_UDP_TUNNEL |	    \
299 		       NETIF_F_GSO_IPIP | NETIF_F_GSO_SIT | NETIF_F_UFO	|   \
300 		       NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
301 		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
302 
303 static void veth_setup(struct net_device *dev)
304 {
305 	ether_setup(dev);
306 
307 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
308 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
309 	dev->priv_flags |= IFF_NO_QUEUE;
310 
311 	dev->netdev_ops = &veth_netdev_ops;
312 	dev->ethtool_ops = &veth_ethtool_ops;
313 	dev->features |= NETIF_F_LLTX;
314 	dev->features |= VETH_FEATURES;
315 	dev->vlan_features = dev->features &
316 			     ~(NETIF_F_HW_VLAN_CTAG_TX |
317 			       NETIF_F_HW_VLAN_STAG_TX |
318 			       NETIF_F_HW_VLAN_CTAG_RX |
319 			       NETIF_F_HW_VLAN_STAG_RX);
320 	dev->destructor = veth_dev_free;
321 
322 	dev->hw_features = VETH_FEATURES;
323 	dev->hw_enc_features = VETH_FEATURES;
324 }
325 
326 /*
327  * netlink interface
328  */
329 
330 static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
331 {
332 	if (tb[IFLA_ADDRESS]) {
333 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
334 			return -EINVAL;
335 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
336 			return -EADDRNOTAVAIL;
337 	}
338 	if (tb[IFLA_MTU]) {
339 		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
340 			return -EINVAL;
341 	}
342 	return 0;
343 }
344 
345 static struct rtnl_link_ops veth_link_ops;
346 
347 static int veth_newlink(struct net *src_net, struct net_device *dev,
348 			 struct nlattr *tb[], struct nlattr *data[])
349 {
350 	int err;
351 	struct net_device *peer;
352 	struct veth_priv *priv;
353 	char ifname[IFNAMSIZ];
354 	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
355 	unsigned char name_assign_type;
356 	struct ifinfomsg *ifmp;
357 	struct net *net;
358 
359 	/*
360 	 * create and register peer first
361 	 */
362 	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
363 		struct nlattr *nla_peer;
364 
365 		nla_peer = data[VETH_INFO_PEER];
366 		ifmp = nla_data(nla_peer);
367 		err = rtnl_nla_parse_ifla(peer_tb,
368 					  nla_data(nla_peer) + sizeof(struct ifinfomsg),
369 					  nla_len(nla_peer) - sizeof(struct ifinfomsg));
370 		if (err < 0)
371 			return err;
372 
373 		err = veth_validate(peer_tb, NULL);
374 		if (err < 0)
375 			return err;
376 
377 		tbp = peer_tb;
378 	} else {
379 		ifmp = NULL;
380 		tbp = tb;
381 	}
382 
383 	if (tbp[IFLA_IFNAME]) {
384 		nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
385 		name_assign_type = NET_NAME_USER;
386 	} else {
387 		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
388 		name_assign_type = NET_NAME_ENUM;
389 	}
390 
391 	net = rtnl_link_get_net(src_net, tbp);
392 	if (IS_ERR(net))
393 		return PTR_ERR(net);
394 
395 	peer = rtnl_create_link(net, ifname, name_assign_type,
396 				&veth_link_ops, tbp);
397 	if (IS_ERR(peer)) {
398 		put_net(net);
399 		return PTR_ERR(peer);
400 	}
401 
402 	if (tbp[IFLA_ADDRESS] == NULL)
403 		eth_hw_addr_random(peer);
404 
405 	if (ifmp && (dev->ifindex != 0))
406 		peer->ifindex = ifmp->ifi_index;
407 
408 	err = register_netdevice(peer);
409 	put_net(net);
410 	net = NULL;
411 	if (err < 0)
412 		goto err_register_peer;
413 
414 	netif_carrier_off(peer);
415 
416 	err = rtnl_configure_link(peer, ifmp);
417 	if (err < 0)
418 		goto err_configure_peer;
419 
420 	/*
421 	 * register dev last
422 	 *
423 	 * note, that since we've registered new device the dev's name
424 	 * should be re-allocated
425 	 */
426 
427 	if (tb[IFLA_ADDRESS] == NULL)
428 		eth_hw_addr_random(dev);
429 
430 	if (tb[IFLA_IFNAME])
431 		nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
432 	else
433 		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
434 
435 	err = register_netdevice(dev);
436 	if (err < 0)
437 		goto err_register_dev;
438 
439 	netif_carrier_off(dev);
440 
441 	/*
442 	 * tie the deviced together
443 	 */
444 
445 	priv = netdev_priv(dev);
446 	rcu_assign_pointer(priv->peer, peer);
447 
448 	priv = netdev_priv(peer);
449 	rcu_assign_pointer(priv->peer, dev);
450 	return 0;
451 
452 err_register_dev:
453 	/* nothing to do */
454 err_configure_peer:
455 	unregister_netdevice(peer);
456 	return err;
457 
458 err_register_peer:
459 	free_netdev(peer);
460 	return err;
461 }
462 
463 static void veth_dellink(struct net_device *dev, struct list_head *head)
464 {
465 	struct veth_priv *priv;
466 	struct net_device *peer;
467 
468 	priv = netdev_priv(dev);
469 	peer = rtnl_dereference(priv->peer);
470 
471 	/* Note : dellink() is called from default_device_exit_batch(),
472 	 * before a rcu_synchronize() point. The devices are guaranteed
473 	 * not being freed before one RCU grace period.
474 	 */
475 	RCU_INIT_POINTER(priv->peer, NULL);
476 	unregister_netdevice_queue(dev, head);
477 
478 	if (peer) {
479 		priv = netdev_priv(peer);
480 		RCU_INIT_POINTER(priv->peer, NULL);
481 		unregister_netdevice_queue(peer, head);
482 	}
483 }
484 
485 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
486 	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
487 };
488 
489 static struct net *veth_get_link_net(const struct net_device *dev)
490 {
491 	struct veth_priv *priv = netdev_priv(dev);
492 	struct net_device *peer = rtnl_dereference(priv->peer);
493 
494 	return peer ? dev_net(peer) : dev_net(dev);
495 }
496 
497 static struct rtnl_link_ops veth_link_ops = {
498 	.kind		= DRV_NAME,
499 	.priv_size	= sizeof(struct veth_priv),
500 	.setup		= veth_setup,
501 	.validate	= veth_validate,
502 	.newlink	= veth_newlink,
503 	.dellink	= veth_dellink,
504 	.policy		= veth_policy,
505 	.maxtype	= VETH_INFO_MAX,
506 	.get_link_net	= veth_get_link_net,
507 };
508 
509 /*
510  * init/fini
511  */
512 
513 static __init int veth_init(void)
514 {
515 	return rtnl_link_register(&veth_link_ops);
516 }
517 
518 static __exit void veth_exit(void)
519 {
520 	rtnl_link_unregister(&veth_link_ops);
521 }
522 
523 module_init(veth_init);
524 module_exit(veth_exit);
525 
526 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
527 MODULE_LICENSE("GPL v2");
528 MODULE_ALIAS_RTNL_LINK(DRV_NAME);
529