xref: /openbmc/linux/drivers/net/veth.c (revision c1d45424) 
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_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
259 		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
260 
261 static void veth_setup(struct net_device *dev)
262 {
263 	ether_setup(dev);
264 
265 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
266 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
267 
268 	dev->netdev_ops = &veth_netdev_ops;
269 	dev->ethtool_ops = &veth_ethtool_ops;
270 	dev->features |= NETIF_F_LLTX;
271 	dev->features |= VETH_FEATURES;
272 	dev->vlan_features = dev->features;
273 	dev->destructor = veth_dev_free;
274 
275 	dev->hw_features = VETH_FEATURES;
276 }
277 
278 /*
279  * netlink interface
280  */
281 
282 static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
283 {
284 	if (tb[IFLA_ADDRESS]) {
285 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
286 			return -EINVAL;
287 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
288 			return -EADDRNOTAVAIL;
289 	}
290 	if (tb[IFLA_MTU]) {
291 		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
292 			return -EINVAL;
293 	}
294 	return 0;
295 }
296 
297 static struct rtnl_link_ops veth_link_ops;
298 
299 static int veth_newlink(struct net *src_net, struct net_device *dev,
300 			 struct nlattr *tb[], struct nlattr *data[])
301 {
302 	int err;
303 	struct net_device *peer;
304 	struct veth_priv *priv;
305 	char ifname[IFNAMSIZ];
306 	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
307 	struct ifinfomsg *ifmp;
308 	struct net *net;
309 
310 	/*
311 	 * create and register peer first
312 	 */
313 	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
314 		struct nlattr *nla_peer;
315 
316 		nla_peer = data[VETH_INFO_PEER];
317 		ifmp = nla_data(nla_peer);
318 		err = nla_parse(peer_tb, IFLA_MAX,
319 				nla_data(nla_peer) + sizeof(struct ifinfomsg),
320 				nla_len(nla_peer) - sizeof(struct ifinfomsg),
321 				ifla_policy);
322 		if (err < 0)
323 			return err;
324 
325 		err = veth_validate(peer_tb, NULL);
326 		if (err < 0)
327 			return err;
328 
329 		tbp = peer_tb;
330 	} else {
331 		ifmp = NULL;
332 		tbp = tb;
333 	}
334 
335 	if (tbp[IFLA_IFNAME])
336 		nla_strlcpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
337 	else
338 		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
339 
340 	net = rtnl_link_get_net(src_net, tbp);
341 	if (IS_ERR(net))
342 		return PTR_ERR(net);
343 
344 	peer = rtnl_create_link(net, ifname, &veth_link_ops, tbp);
345 	if (IS_ERR(peer)) {
346 		put_net(net);
347 		return PTR_ERR(peer);
348 	}
349 
350 	if (tbp[IFLA_ADDRESS] == NULL)
351 		eth_hw_addr_random(peer);
352 
353 	if (ifmp && (dev->ifindex != 0))
354 		peer->ifindex = ifmp->ifi_index;
355 
356 	err = register_netdevice(peer);
357 	put_net(net);
358 	net = NULL;
359 	if (err < 0)
360 		goto err_register_peer;
361 
362 	netif_carrier_off(peer);
363 
364 	err = rtnl_configure_link(peer, ifmp);
365 	if (err < 0)
366 		goto err_configure_peer;
367 
368 	/*
369 	 * register dev last
370 	 *
371 	 * note, that since we've registered new device the dev's name
372 	 * should be re-allocated
373 	 */
374 
375 	if (tb[IFLA_ADDRESS] == NULL)
376 		eth_hw_addr_random(dev);
377 
378 	if (tb[IFLA_IFNAME])
379 		nla_strlcpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
380 	else
381 		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
382 
383 	err = register_netdevice(dev);
384 	if (err < 0)
385 		goto err_register_dev;
386 
387 	netif_carrier_off(dev);
388 
389 	/*
390 	 * tie the deviced together
391 	 */
392 
393 	priv = netdev_priv(dev);
394 	rcu_assign_pointer(priv->peer, peer);
395 
396 	priv = netdev_priv(peer);
397 	rcu_assign_pointer(priv->peer, dev);
398 	return 0;
399 
400 err_register_dev:
401 	/* nothing to do */
402 err_configure_peer:
403 	unregister_netdevice(peer);
404 	return err;
405 
406 err_register_peer:
407 	free_netdev(peer);
408 	return err;
409 }
410 
411 static void veth_dellink(struct net_device *dev, struct list_head *head)
412 {
413 	struct veth_priv *priv;
414 	struct net_device *peer;
415 
416 	priv = netdev_priv(dev);
417 	peer = rtnl_dereference(priv->peer);
418 
419 	/* Note : dellink() is called from default_device_exit_batch(),
420 	 * before a rcu_synchronize() point. The devices are guaranteed
421 	 * not being freed before one RCU grace period.
422 	 */
423 	RCU_INIT_POINTER(priv->peer, NULL);
424 	unregister_netdevice_queue(dev, head);
425 
426 	if (peer) {
427 		priv = netdev_priv(peer);
428 		RCU_INIT_POINTER(priv->peer, NULL);
429 		unregister_netdevice_queue(peer, head);
430 	}
431 }
432 
433 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
434 	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
435 };
436 
437 static struct rtnl_link_ops veth_link_ops = {
438 	.kind		= DRV_NAME,
439 	.priv_size	= sizeof(struct veth_priv),
440 	.setup		= veth_setup,
441 	.validate	= veth_validate,
442 	.newlink	= veth_newlink,
443 	.dellink	= veth_dellink,
444 	.policy		= veth_policy,
445 	.maxtype	= VETH_INFO_MAX,
446 };
447 
448 /*
449  * init/fini
450  */
451 
452 static __init int veth_init(void)
453 {
454 	return rtnl_link_register(&veth_link_ops);
455 }
456 
457 static __exit void veth_exit(void)
458 {
459 	rtnl_link_unregister(&veth_link_ops);
460 }
461 
462 module_init(veth_init);
463 module_exit(veth_exit);
464 
465 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
466 MODULE_LICENSE("GPL v2");
467 MODULE_ALIAS_RTNL_LINK(DRV_NAME);
468