xref: /openbmc/linux/drivers/net/veth.c (revision 9a69abf8) 
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/dst.h>
18 #include <net/xfrm.h>
19 #include <linux/veth.h>
20 #include <linux/module.h>
21 
22 #define DRV_NAME	"veth"
23 #define DRV_VERSION	"1.0"
24 
25 #define MIN_MTU 68		/* Min L3 MTU */
26 #define MAX_MTU 65535		/* Max L3 MTU (arbitrary) */
27 
28 struct pcpu_vstats {
29 	u64			packets;
30 	u64			bytes;
31 	struct u64_stats_sync	syncp;
32 };
33 
34 struct veth_priv {
35 	struct net_device __rcu	*peer;
36 	atomic64_t		dropped;
37 };
38 
39 /*
40  * ethtool interface
41  */
42 
43 static struct {
44 	const char string[ETH_GSTRING_LEN];
45 } ethtool_stats_keys[] = {
46 	{ "peer_ifindex" },
47 };
48 
49 static int veth_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
50 {
51 	cmd->supported		= 0;
52 	cmd->advertising	= 0;
53 	ethtool_cmd_speed_set(cmd, SPEED_10000);
54 	cmd->duplex		= DUPLEX_FULL;
55 	cmd->port		= PORT_TP;
56 	cmd->phy_address	= 0;
57 	cmd->transceiver	= XCVR_INTERNAL;
58 	cmd->autoneg		= AUTONEG_DISABLE;
59 	cmd->maxtxpkt		= 0;
60 	cmd->maxrxpkt		= 0;
61 	return 0;
62 }
63 
64 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
65 {
66 	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
67 	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
68 }
69 
70 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
71 {
72 	switch(stringset) {
73 	case ETH_SS_STATS:
74 		memcpy(buf, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
75 		break;
76 	}
77 }
78 
79 static int veth_get_sset_count(struct net_device *dev, int sset)
80 {
81 	switch (sset) {
82 	case ETH_SS_STATS:
83 		return ARRAY_SIZE(ethtool_stats_keys);
84 	default:
85 		return -EOPNOTSUPP;
86 	}
87 }
88 
89 static void veth_get_ethtool_stats(struct net_device *dev,
90 		struct ethtool_stats *stats, u64 *data)
91 {
92 	struct veth_priv *priv = netdev_priv(dev);
93 	struct net_device *peer = rtnl_dereference(priv->peer);
94 
95 	data[0] = peer ? peer->ifindex : 0;
96 }
97 
98 static const struct ethtool_ops veth_ethtool_ops = {
99 	.get_settings		= veth_get_settings,
100 	.get_drvinfo		= veth_get_drvinfo,
101 	.get_link		= ethtool_op_get_link,
102 	.get_strings		= veth_get_strings,
103 	.get_sset_count		= veth_get_sset_count,
104 	.get_ethtool_stats	= veth_get_ethtool_stats,
105 };
106 
107 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
108 {
109 	struct veth_priv *priv = netdev_priv(dev);
110 	struct net_device *rcv;
111 	int length = skb->len;
112 
113 	rcu_read_lock();
114 	rcv = rcu_dereference(priv->peer);
115 	if (unlikely(!rcv)) {
116 		kfree_skb(skb);
117 		goto drop;
118 	}
119 	/* don't change ip_summed == CHECKSUM_PARTIAL, as that
120 	 * will cause bad checksum on forwarded packets
121 	 */
122 	if (skb->ip_summed == CHECKSUM_NONE &&
123 	    rcv->features & NETIF_F_RXCSUM)
124 		skb->ip_summed = CHECKSUM_UNNECESSARY;
125 
126 	if (likely(dev_forward_skb(rcv, skb) == NET_RX_SUCCESS)) {
127 		struct pcpu_vstats *stats = this_cpu_ptr(dev->vstats);
128 
129 		u64_stats_update_begin(&stats->syncp);
130 		stats->bytes += length;
131 		stats->packets++;
132 		u64_stats_update_end(&stats->syncp);
133 	} else {
134 drop:
135 		atomic64_inc(&priv->dropped);
136 	}
137 	rcu_read_unlock();
138 	return NETDEV_TX_OK;
139 }
140 
141 /*
142  * general routines
143  */
144 
145 static u64 veth_stats_one(struct pcpu_vstats *result, struct net_device *dev)
146 {
147 	struct veth_priv *priv = netdev_priv(dev);
148 	int cpu;
149 
150 	result->packets = 0;
151 	result->bytes = 0;
152 	for_each_possible_cpu(cpu) {
153 		struct pcpu_vstats *stats = per_cpu_ptr(dev->vstats, cpu);
154 		u64 packets, bytes;
155 		unsigned int start;
156 
157 		do {
158 			start = u64_stats_fetch_begin_bh(&stats->syncp);
159 			packets = stats->packets;
160 			bytes = stats->bytes;
161 		} while (u64_stats_fetch_retry_bh(&stats->syncp, start));
162 		result->packets += packets;
163 		result->bytes += bytes;
164 	}
165 	return atomic64_read(&priv->dropped);
166 }
167 
168 static struct rtnl_link_stats64 *veth_get_stats64(struct net_device *dev,
169 						  struct rtnl_link_stats64 *tot)
170 {
171 	struct veth_priv *priv = netdev_priv(dev);
172 	struct net_device *peer;
173 	struct pcpu_vstats one;
174 
175 	tot->tx_dropped = veth_stats_one(&one, dev);
176 	tot->tx_bytes = one.bytes;
177 	tot->tx_packets = one.packets;
178 
179 	rcu_read_lock();
180 	peer = rcu_dereference(priv->peer);
181 	if (peer) {
182 		tot->rx_dropped = veth_stats_one(&one, peer);
183 		tot->rx_bytes = one.bytes;
184 		tot->rx_packets = one.packets;
185 	}
186 	rcu_read_unlock();
187 
188 	return tot;
189 }
190 
191 static int veth_open(struct net_device *dev)
192 {
193 	struct veth_priv *priv = netdev_priv(dev);
194 	struct net_device *peer = rtnl_dereference(priv->peer);
195 
196 	if (!peer)
197 		return -ENOTCONN;
198 
199 	if (peer->flags & IFF_UP) {
200 		netif_carrier_on(dev);
201 		netif_carrier_on(peer);
202 	}
203 	return 0;
204 }
205 
206 static int veth_close(struct net_device *dev)
207 {
208 	struct veth_priv *priv = netdev_priv(dev);
209 	struct net_device *peer = rtnl_dereference(priv->peer);
210 
211 	netif_carrier_off(dev);
212 	if (peer)
213 		netif_carrier_off(peer);
214 
215 	return 0;
216 }
217 
218 static int is_valid_veth_mtu(int new_mtu)
219 {
220 	return new_mtu >= MIN_MTU && new_mtu <= MAX_MTU;
221 }
222 
223 static int veth_change_mtu(struct net_device *dev, int new_mtu)
224 {
225 	if (!is_valid_veth_mtu(new_mtu))
226 		return -EINVAL;
227 	dev->mtu = new_mtu;
228 	return 0;
229 }
230 
231 static int veth_dev_init(struct net_device *dev)
232 {
233 	dev->vstats = alloc_percpu(struct pcpu_vstats);
234 	if (!dev->vstats)
235 		return -ENOMEM;
236 
237 	return 0;
238 }
239 
240 static void veth_dev_free(struct net_device *dev)
241 {
242 	free_percpu(dev->vstats);
243 	free_netdev(dev);
244 }
245 
246 static const struct net_device_ops veth_netdev_ops = {
247 	.ndo_init            = veth_dev_init,
248 	.ndo_open            = veth_open,
249 	.ndo_stop            = veth_close,
250 	.ndo_start_xmit      = veth_xmit,
251 	.ndo_change_mtu      = veth_change_mtu,
252 	.ndo_get_stats64     = veth_get_stats64,
253 	.ndo_set_mac_address = eth_mac_addr,
254 };
255 
256 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO |    \
257 		       NETIF_F_HW_CSUM | NETIF_F_RXCSUM | NETIF_F_HIGHDMA | \
258 		       NETIF_F_HW_VLAN_TX | NETIF_F_HW_VLAN_RX)
259 
260 static void veth_setup(struct net_device *dev)
261 {
262 	ether_setup(dev);
263 
264 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
265 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
266 
267 	dev->netdev_ops = &veth_netdev_ops;
268 	dev->ethtool_ops = &veth_ethtool_ops;
269 	dev->features |= NETIF_F_LLTX;
270 	dev->features |= VETH_FEATURES;
271 	dev->destructor = veth_dev_free;
272 
273 	dev->hw_features = VETH_FEATURES;
274 }
275 
276 /*
277  * netlink interface
278  */
279 
280 static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
281 {
282 	if (tb[IFLA_ADDRESS]) {
283 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
284 			return -EINVAL;
285 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
286 			return -EADDRNOTAVAIL;
287 	}
288 	if (tb[IFLA_MTU]) {
289 		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
290 			return -EINVAL;
291 	}
292 	return 0;
293 }
294 
295 static struct rtnl_link_ops veth_link_ops;
296 
297 static int veth_newlink(struct net *src_net, struct net_device *dev,
298 			 struct nlattr *tb[], struct nlattr *data[])
299 {
300 	int err;
301 	struct net_device *peer;
302 	struct veth_priv *priv;
303 	char ifname[IFNAMSIZ];
304 	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
305 	struct ifinfomsg *ifmp;
306 	struct net *net;
307 
308 	/*
309 	 * create and register peer first
310 	 */
311 	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
312 		struct nlattr *nla_peer;
313 
314 		nla_peer = data[VETH_INFO_PEER];
315 		ifmp = nla_data(nla_peer);
316 		err = nla_parse(peer_tb, IFLA_MAX,
317 				nla_data(nla_peer) + sizeof(struct ifinfomsg),
318 				nla_len(nla_peer) - sizeof(struct ifinfomsg),
319 				ifla_policy);
320 		if (err < 0)
321 			return err;
322 
323 		err = veth_validate(peer_tb, NULL);
324 		if (err < 0)
325 			return err;
326 
327 		tbp = peer_tb;
328 	} else {
329 		ifmp = NULL;
330 		tbp = tb;
331 	}
332 
333 	if (tbp[IFLA_IFNAME])
334 		nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
335 	else
336 		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
337 
338 	net = rtnl_link_get_net(src_net, tbp);
339 	if (IS_ERR(net))
340 		return PTR_ERR(net);
341 
342 	peer = rtnl_create_link(net, ifname, &veth_link_ops, tbp);
343 	if (IS_ERR(peer)) {
344 		put_net(net);
345 		return PTR_ERR(peer);
346 	}
347 
348 	if (tbp[IFLA_ADDRESS] == NULL)
349 		eth_hw_addr_random(peer);
350 
351 	if (ifmp && (dev->ifindex != 0))
352 		peer->ifindex = ifmp->ifi_index;
353 
354 	err = register_netdevice(peer);
355 	put_net(net);
356 	net = NULL;
357 	if (err < 0)
358 		goto err_register_peer;
359 
360 	netif_carrier_off(peer);
361 
362 	err = rtnl_configure_link(peer, ifmp);
363 	if (err < 0)
364 		goto err_configure_peer;
365 
366 	/*
367 	 * register dev last
368 	 *
369 	 * note, that since we've registered new device the dev's name
370 	 * should be re-allocated
371 	 */
372 
373 	if (tb[IFLA_ADDRESS] == NULL)
374 		eth_hw_addr_random(dev);
375 
376 	if (tb[IFLA_IFNAME])
377 		nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
378 	else
379 		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
380 
381 	if (strchr(dev->name, '%')) {
382 		err = dev_alloc_name(dev, dev->name);
383 		if (err < 0)
384 			goto err_alloc_name;
385 	}
386 
387 	err = register_netdevice(dev);
388 	if (err < 0)
389 		goto err_register_dev;
390 
391 	netif_carrier_off(dev);
392 
393 	/*
394 	 * tie the deviced together
395 	 */
396 
397 	priv = netdev_priv(dev);
398 	rcu_assign_pointer(priv->peer, peer);
399 
400 	priv = netdev_priv(peer);
401 	rcu_assign_pointer(priv->peer, dev);
402 	return 0;
403 
404 err_register_dev:
405 	/* nothing to do */
406 err_alloc_name:
407 err_configure_peer:
408 	unregister_netdevice(peer);
409 	return err;
410 
411 err_register_peer:
412 	free_netdev(peer);
413 	return err;
414 }
415 
416 static void veth_dellink(struct net_device *dev, struct list_head *head)
417 {
418 	struct veth_priv *priv;
419 	struct net_device *peer;
420 
421 	priv = netdev_priv(dev);
422 	peer = rtnl_dereference(priv->peer);
423 
424 	/* Note : dellink() is called from default_device_exit_batch(),
425 	 * before a rcu_synchronize() point. The devices are guaranteed
426 	 * not being freed before one RCU grace period.
427 	 */
428 	RCU_INIT_POINTER(priv->peer, NULL);
429 	unregister_netdevice_queue(dev, head);
430 
431 	if (peer) {
432 		priv = netdev_priv(peer);
433 		RCU_INIT_POINTER(priv->peer, NULL);
434 		unregister_netdevice_queue(peer, head);
435 	}
436 }
437 
438 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
439 	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
440 };
441 
442 static struct rtnl_link_ops veth_link_ops = {
443 	.kind		= DRV_NAME,
444 	.priv_size	= sizeof(struct veth_priv),
445 	.setup		= veth_setup,
446 	.validate	= veth_validate,
447 	.newlink	= veth_newlink,
448 	.dellink	= veth_dellink,
449 	.policy		= veth_policy,
450 	.maxtype	= VETH_INFO_MAX,
451 };
452 
453 /*
454  * init/fini
455  */
456 
457 static __init int veth_init(void)
458 {
459 	return rtnl_link_register(&veth_link_ops);
460 }
461 
462 static __exit void veth_exit(void)
463 {
464 	rtnl_link_unregister(&veth_link_ops);
465 }
466 
467 module_init(veth_init);
468 module_exit(veth_exit);
469 
470 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
471 MODULE_LICENSE("GPL v2");
472 MODULE_ALIAS_RTNL_LINK(DRV_NAME);
473