xref: /openbmc/linux/drivers/net/vrf.c (revision e63c7a0979f28bb13e06b981765dd514c01c075b) 
1 /*
2  * vrf.c: device driver to encapsulate a VRF space
3  *
4  * Copyright (c) 2015 Cumulus Networks. All rights reserved.
5  * Copyright (c) 2015 Shrijeet Mukherjee <shm@cumulusnetworks.com>
6  * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
7  *
8  * Based on dummy, team and ipvlan drivers
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/netdevice.h>
19 #include <linux/etherdevice.h>
20 #include <linux/ip.h>
21 #include <linux/init.h>
22 #include <linux/moduleparam.h>
23 #include <linux/netfilter.h>
24 #include <linux/rtnetlink.h>
25 #include <net/rtnetlink.h>
26 #include <linux/u64_stats_sync.h>
27 #include <linux/hashtable.h>
28 
29 #include <linux/inetdevice.h>
30 #include <net/arp.h>
31 #include <net/ip.h>
32 #include <net/ip_fib.h>
33 #include <net/ip6_route.h>
34 #include <net/rtnetlink.h>
35 #include <net/route.h>
36 #include <net/addrconf.h>
37 #include <net/vrf.h>
38 
39 #define DRV_NAME	"vrf"
40 #define DRV_VERSION	"1.0"
41 
42 #define vrf_is_slave(dev)   ((dev)->flags & IFF_SLAVE)
43 
44 #define vrf_master_get_rcu(dev) \
45 	((struct net_device *)rcu_dereference(dev->rx_handler_data))
46 
47 struct pcpu_dstats {
48 	u64			tx_pkts;
49 	u64			tx_bytes;
50 	u64			tx_drps;
51 	u64			rx_pkts;
52 	u64			rx_bytes;
53 	struct u64_stats_sync	syncp;
54 };
55 
56 static struct dst_entry *vrf_ip_check(struct dst_entry *dst, u32 cookie)
57 {
58 	return dst;
59 }
60 
61 static int vrf_ip_local_out(struct sk_buff *skb)
62 {
63 	return ip_local_out(skb);
64 }
65 
66 static unsigned int vrf_v4_mtu(const struct dst_entry *dst)
67 {
68 	/* TO-DO: return max ethernet size? */
69 	return dst->dev->mtu;
70 }
71 
72 static void vrf_dst_destroy(struct dst_entry *dst)
73 {
74 	/* our dst lives forever - or until the device is closed */
75 }
76 
77 static unsigned int vrf_default_advmss(const struct dst_entry *dst)
78 {
79 	return 65535 - 40;
80 }
81 
82 static struct dst_ops vrf_dst_ops = {
83 	.family		= AF_INET,
84 	.local_out	= vrf_ip_local_out,
85 	.check		= vrf_ip_check,
86 	.mtu		= vrf_v4_mtu,
87 	.destroy	= vrf_dst_destroy,
88 	.default_advmss	= vrf_default_advmss,
89 };
90 
91 static bool is_ip_rx_frame(struct sk_buff *skb)
92 {
93 	switch (skb->protocol) {
94 	case htons(ETH_P_IP):
95 	case htons(ETH_P_IPV6):
96 		return true;
97 	}
98 	return false;
99 }
100 
101 static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb)
102 {
103 	vrf_dev->stats.tx_errors++;
104 	kfree_skb(skb);
105 }
106 
107 /* note: already called with rcu_read_lock */
108 static rx_handler_result_t vrf_handle_frame(struct sk_buff **pskb)
109 {
110 	struct sk_buff *skb = *pskb;
111 
112 	if (is_ip_rx_frame(skb)) {
113 		struct net_device *dev = vrf_master_get_rcu(skb->dev);
114 		struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
115 
116 		u64_stats_update_begin(&dstats->syncp);
117 		dstats->rx_pkts++;
118 		dstats->rx_bytes += skb->len;
119 		u64_stats_update_end(&dstats->syncp);
120 
121 		skb->dev = dev;
122 
123 		return RX_HANDLER_ANOTHER;
124 	}
125 	return RX_HANDLER_PASS;
126 }
127 
128 static struct rtnl_link_stats64 *vrf_get_stats64(struct net_device *dev,
129 						 struct rtnl_link_stats64 *stats)
130 {
131 	int i;
132 
133 	for_each_possible_cpu(i) {
134 		const struct pcpu_dstats *dstats;
135 		u64 tbytes, tpkts, tdrops, rbytes, rpkts;
136 		unsigned int start;
137 
138 		dstats = per_cpu_ptr(dev->dstats, i);
139 		do {
140 			start = u64_stats_fetch_begin_irq(&dstats->syncp);
141 			tbytes = dstats->tx_bytes;
142 			tpkts = dstats->tx_pkts;
143 			tdrops = dstats->tx_drps;
144 			rbytes = dstats->rx_bytes;
145 			rpkts = dstats->rx_pkts;
146 		} while (u64_stats_fetch_retry_irq(&dstats->syncp, start));
147 		stats->tx_bytes += tbytes;
148 		stats->tx_packets += tpkts;
149 		stats->tx_dropped += tdrops;
150 		stats->rx_bytes += rbytes;
151 		stats->rx_packets += rpkts;
152 	}
153 	return stats;
154 }
155 
156 static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb,
157 					   struct net_device *dev)
158 {
159 	vrf_tx_error(dev, skb);
160 	return NET_XMIT_DROP;
161 }
162 
163 static int vrf_send_v4_prep(struct sk_buff *skb, struct flowi4 *fl4,
164 			    struct net_device *vrf_dev)
165 {
166 	struct rtable *rt;
167 	int err = 1;
168 
169 	rt = ip_route_output_flow(dev_net(vrf_dev), fl4, NULL);
170 	if (IS_ERR(rt))
171 		goto out;
172 
173 	/* TO-DO: what about broadcast ? */
174 	if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) {
175 		ip_rt_put(rt);
176 		goto out;
177 	}
178 
179 	skb_dst_drop(skb);
180 	skb_dst_set(skb, &rt->dst);
181 	err = 0;
182 out:
183 	return err;
184 }
185 
186 static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb,
187 					   struct net_device *vrf_dev)
188 {
189 	struct iphdr *ip4h = ip_hdr(skb);
190 	int ret = NET_XMIT_DROP;
191 	struct flowi4 fl4 = {
192 		/* needed to match OIF rule */
193 		.flowi4_oif = vrf_dev->ifindex,
194 		.flowi4_iif = LOOPBACK_IFINDEX,
195 		.flowi4_tos = RT_TOS(ip4h->tos),
196 		.flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_VRFSRC,
197 		.daddr = ip4h->daddr,
198 	};
199 
200 	if (vrf_send_v4_prep(skb, &fl4, vrf_dev))
201 		goto err;
202 
203 	if (!ip4h->saddr) {
204 		ip4h->saddr = inet_select_addr(skb_dst(skb)->dev, 0,
205 					       RT_SCOPE_LINK);
206 	}
207 
208 	ret = ip_local_out(skb);
209 	if (unlikely(net_xmit_eval(ret)))
210 		vrf_dev->stats.tx_errors++;
211 	else
212 		ret = NET_XMIT_SUCCESS;
213 
214 out:
215 	return ret;
216 err:
217 	vrf_tx_error(vrf_dev, skb);
218 	goto out;
219 }
220 
221 static netdev_tx_t is_ip_tx_frame(struct sk_buff *skb, struct net_device *dev)
222 {
223 	/* strip the ethernet header added for pass through VRF device */
224 	__skb_pull(skb, skb_network_offset(skb));
225 
226 	switch (skb->protocol) {
227 	case htons(ETH_P_IP):
228 		return vrf_process_v4_outbound(skb, dev);
229 	case htons(ETH_P_IPV6):
230 		return vrf_process_v6_outbound(skb, dev);
231 	default:
232 		vrf_tx_error(dev, skb);
233 		return NET_XMIT_DROP;
234 	}
235 }
236 
237 static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev)
238 {
239 	netdev_tx_t ret = is_ip_tx_frame(skb, dev);
240 
241 	if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
242 		struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
243 
244 		u64_stats_update_begin(&dstats->syncp);
245 		dstats->tx_pkts++;
246 		dstats->tx_bytes += skb->len;
247 		u64_stats_update_end(&dstats->syncp);
248 	} else {
249 		this_cpu_inc(dev->dstats->tx_drps);
250 	}
251 
252 	return ret;
253 }
254 
255 /* modelled after ip_finish_output2 */
256 static int vrf_finish_output(struct sock *sk, struct sk_buff *skb)
257 {
258 	struct dst_entry *dst = skb_dst(skb);
259 	struct rtable *rt = (struct rtable *)dst;
260 	struct net_device *dev = dst->dev;
261 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
262 	struct neighbour *neigh;
263 	u32 nexthop;
264 	int ret = -EINVAL;
265 
266 	/* Be paranoid, rather than too clever. */
267 	if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
268 		struct sk_buff *skb2;
269 
270 		skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
271 		if (!skb2) {
272 			ret = -ENOMEM;
273 			goto err;
274 		}
275 		if (skb->sk)
276 			skb_set_owner_w(skb2, skb->sk);
277 
278 		consume_skb(skb);
279 		skb = skb2;
280 	}
281 
282 	rcu_read_lock_bh();
283 
284 	nexthop = (__force u32)rt_nexthop(rt, ip_hdr(skb)->daddr);
285 	neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
286 	if (unlikely(!neigh))
287 		neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
288 	if (!IS_ERR(neigh))
289 		ret = dst_neigh_output(dst, neigh, skb);
290 
291 	rcu_read_unlock_bh();
292 err:
293 	if (unlikely(ret < 0))
294 		vrf_tx_error(skb->dev, skb);
295 	return ret;
296 }
297 
298 static int vrf_output(struct sock *sk, struct sk_buff *skb)
299 {
300 	struct net_device *dev = skb_dst(skb)->dev;
301 
302 	IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
303 
304 	skb->dev = dev;
305 	skb->protocol = htons(ETH_P_IP);
306 
307 	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb,
308 			    NULL, dev,
309 			    vrf_finish_output,
310 			    !(IPCB(skb)->flags & IPSKB_REROUTED));
311 }
312 
313 static void vrf_rtable_destroy(struct net_vrf *vrf)
314 {
315 	struct dst_entry *dst = (struct dst_entry *)vrf->rth;
316 
317 	dst_destroy(dst);
318 	vrf->rth = NULL;
319 }
320 
321 static struct rtable *vrf_rtable_create(struct net_device *dev)
322 {
323 	struct net_vrf *vrf = netdev_priv(dev);
324 	struct rtable *rth;
325 
326 	rth = dst_alloc(&vrf_dst_ops, dev, 2,
327 			DST_OBSOLETE_NONE,
328 			(DST_HOST | DST_NOPOLICY | DST_NOXFRM));
329 	if (rth) {
330 		rth->dst.output	= vrf_output;
331 		rth->rt_genid	= rt_genid_ipv4(dev_net(dev));
332 		rth->rt_flags	= 0;
333 		rth->rt_type	= RTN_UNICAST;
334 		rth->rt_is_input = 0;
335 		rth->rt_iif	= 0;
336 		rth->rt_pmtu	= 0;
337 		rth->rt_gateway	= 0;
338 		rth->rt_uses_gateway = 0;
339 		rth->rt_table_id = vrf->tb_id;
340 		INIT_LIST_HEAD(&rth->rt_uncached);
341 		rth->rt_uncached_list = NULL;
342 	}
343 
344 	return rth;
345 }
346 
347 /**************************** device handling ********************/
348 
349 /* cycle interface to flush neighbor cache and move routes across tables */
350 static void cycle_netdev(struct net_device *dev)
351 {
352 	unsigned int flags = dev->flags;
353 	int ret;
354 
355 	if (!netif_running(dev))
356 		return;
357 
358 	ret = dev_change_flags(dev, flags & ~IFF_UP);
359 	if (ret >= 0)
360 		ret = dev_change_flags(dev, flags);
361 
362 	if (ret < 0) {
363 		netdev_err(dev,
364 			   "Failed to cycle device %s; route tables might be wrong!\n",
365 			   dev->name);
366 	}
367 }
368 
369 static struct slave *__vrf_find_slave_dev(struct slave_queue *queue,
370 					  struct net_device *dev)
371 {
372 	struct list_head *head = &queue->all_slaves;
373 	struct slave *slave;
374 
375 	list_for_each_entry(slave, head, list) {
376 		if (slave->dev == dev)
377 			return slave;
378 	}
379 
380 	return NULL;
381 }
382 
383 /* inverse of __vrf_insert_slave */
384 static void __vrf_remove_slave(struct slave_queue *queue, struct slave *slave)
385 {
386 	list_del(&slave->list);
387 }
388 
389 static void __vrf_insert_slave(struct slave_queue *queue, struct slave *slave)
390 {
391 	list_add(&slave->list, &queue->all_slaves);
392 }
393 
394 static int do_vrf_add_slave(struct net_device *dev, struct net_device *port_dev)
395 {
396 	struct net_vrf_dev *vrf_ptr = kmalloc(sizeof(*vrf_ptr), GFP_KERNEL);
397 	struct slave *slave = kzalloc(sizeof(*slave), GFP_KERNEL);
398 	struct net_vrf *vrf = netdev_priv(dev);
399 	struct slave_queue *queue = &vrf->queue;
400 	int ret = -ENOMEM;
401 
402 	if (!slave || !vrf_ptr)
403 		goto out_fail;
404 
405 	slave->dev = port_dev;
406 	vrf_ptr->ifindex = dev->ifindex;
407 	vrf_ptr->tb_id = vrf->tb_id;
408 
409 	/* register the packet handler for slave ports */
410 	ret = netdev_rx_handler_register(port_dev, vrf_handle_frame, dev);
411 	if (ret) {
412 		netdev_err(port_dev,
413 			   "Device %s failed to register rx_handler\n",
414 			   port_dev->name);
415 		goto out_fail;
416 	}
417 
418 	ret = netdev_master_upper_dev_link(port_dev, dev);
419 	if (ret < 0)
420 		goto out_unregister;
421 
422 	port_dev->flags |= IFF_SLAVE;
423 	__vrf_insert_slave(queue, slave);
424 	rcu_assign_pointer(port_dev->vrf_ptr, vrf_ptr);
425 	cycle_netdev(port_dev);
426 
427 	return 0;
428 
429 out_unregister:
430 	netdev_rx_handler_unregister(port_dev);
431 out_fail:
432 	kfree(vrf_ptr);
433 	kfree(slave);
434 	return ret;
435 }
436 
437 static int vrf_add_slave(struct net_device *dev, struct net_device *port_dev)
438 {
439 	if (netif_is_vrf(port_dev) || vrf_is_slave(port_dev))
440 		return -EINVAL;
441 
442 	return do_vrf_add_slave(dev, port_dev);
443 }
444 
445 /* inverse of do_vrf_add_slave */
446 static int do_vrf_del_slave(struct net_device *dev, struct net_device *port_dev)
447 {
448 	struct net_vrf_dev *vrf_ptr = rtnl_dereference(port_dev->vrf_ptr);
449 	struct net_vrf *vrf = netdev_priv(dev);
450 	struct slave_queue *queue = &vrf->queue;
451 	struct slave *slave;
452 
453 	RCU_INIT_POINTER(port_dev->vrf_ptr, NULL);
454 
455 	netdev_upper_dev_unlink(port_dev, dev);
456 	port_dev->flags &= ~IFF_SLAVE;
457 
458 	netdev_rx_handler_unregister(port_dev);
459 
460 	/* after netdev_rx_handler_unregister for synchronize_rcu */
461 	kfree(vrf_ptr);
462 
463 	cycle_netdev(port_dev);
464 
465 	slave = __vrf_find_slave_dev(queue, port_dev);
466 	if (slave)
467 		__vrf_remove_slave(queue, slave);
468 
469 	kfree(slave);
470 
471 	return 0;
472 }
473 
474 static int vrf_del_slave(struct net_device *dev, struct net_device *port_dev)
475 {
476 	return do_vrf_del_slave(dev, port_dev);
477 }
478 
479 static void vrf_dev_uninit(struct net_device *dev)
480 {
481 	struct net_vrf *vrf = netdev_priv(dev);
482 	struct slave_queue *queue = &vrf->queue;
483 	struct list_head *head = &queue->all_slaves;
484 	struct slave *slave, *next;
485 
486 	vrf_rtable_destroy(vrf);
487 
488 	list_for_each_entry_safe(slave, next, head, list)
489 		vrf_del_slave(dev, slave->dev);
490 
491 	free_percpu(dev->dstats);
492 	dev->dstats = NULL;
493 }
494 
495 static int vrf_dev_init(struct net_device *dev)
496 {
497 	struct net_vrf *vrf = netdev_priv(dev);
498 
499 	INIT_LIST_HEAD(&vrf->queue.all_slaves);
500 
501 	dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
502 	if (!dev->dstats)
503 		goto out_nomem;
504 
505 	/* create the default dst which points back to us */
506 	vrf->rth = vrf_rtable_create(dev);
507 	if (!vrf->rth)
508 		goto out_stats;
509 
510 	dev->flags = IFF_MASTER | IFF_NOARP;
511 
512 	return 0;
513 
514 out_stats:
515 	free_percpu(dev->dstats);
516 	dev->dstats = NULL;
517 out_nomem:
518 	return -ENOMEM;
519 }
520 
521 static const struct net_device_ops vrf_netdev_ops = {
522 	.ndo_init		= vrf_dev_init,
523 	.ndo_uninit		= vrf_dev_uninit,
524 	.ndo_start_xmit		= vrf_xmit,
525 	.ndo_get_stats64	= vrf_get_stats64,
526 	.ndo_add_slave		= vrf_add_slave,
527 	.ndo_del_slave		= vrf_del_slave,
528 };
529 
530 static void vrf_get_drvinfo(struct net_device *dev,
531 			    struct ethtool_drvinfo *info)
532 {
533 	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
534 	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
535 }
536 
537 static const struct ethtool_ops vrf_ethtool_ops = {
538 	.get_drvinfo	= vrf_get_drvinfo,
539 };
540 
541 static void vrf_setup(struct net_device *dev)
542 {
543 	ether_setup(dev);
544 
545 	/* Initialize the device structure. */
546 	dev->netdev_ops = &vrf_netdev_ops;
547 	dev->ethtool_ops = &vrf_ethtool_ops;
548 	dev->destructor = free_netdev;
549 
550 	/* Fill in device structure with ethernet-generic values. */
551 	eth_hw_addr_random(dev);
552 
553 	/* don't acquire vrf device's netif_tx_lock when transmitting */
554 	dev->features |= NETIF_F_LLTX;
555 
556 	/* don't allow vrf devices to change network namespaces. */
557 	dev->features |= NETIF_F_NETNS_LOCAL;
558 }
559 
560 static int vrf_validate(struct nlattr *tb[], struct nlattr *data[])
561 {
562 	if (tb[IFLA_ADDRESS]) {
563 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
564 			return -EINVAL;
565 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
566 			return -EADDRNOTAVAIL;
567 	}
568 	return 0;
569 }
570 
571 static void vrf_dellink(struct net_device *dev, struct list_head *head)
572 {
573 	struct net_vrf_dev *vrf_ptr = rtnl_dereference(dev->vrf_ptr);
574 
575 	RCU_INIT_POINTER(dev->vrf_ptr, NULL);
576 	kfree_rcu(vrf_ptr, rcu);
577 	unregister_netdevice_queue(dev, head);
578 }
579 
580 static int vrf_newlink(struct net *src_net, struct net_device *dev,
581 		       struct nlattr *tb[], struct nlattr *data[])
582 {
583 	struct net_vrf *vrf = netdev_priv(dev);
584 	struct net_vrf_dev *vrf_ptr;
585 	int err;
586 
587 	if (!data || !data[IFLA_VRF_TABLE])
588 		return -EINVAL;
589 
590 	vrf->tb_id = nla_get_u32(data[IFLA_VRF_TABLE]);
591 
592 	dev->priv_flags |= IFF_VRF_MASTER;
593 
594 	err = -ENOMEM;
595 	vrf_ptr = kmalloc(sizeof(*dev->vrf_ptr), GFP_KERNEL);
596 	if (!vrf_ptr)
597 		goto out_fail;
598 
599 	vrf_ptr->ifindex = dev->ifindex;
600 	vrf_ptr->tb_id = vrf->tb_id;
601 
602 	err = register_netdevice(dev);
603 	if (err < 0)
604 		goto out_fail;
605 
606 	rcu_assign_pointer(dev->vrf_ptr, vrf_ptr);
607 
608 	return 0;
609 
610 out_fail:
611 	kfree(vrf_ptr);
612 	free_netdev(dev);
613 	return err;
614 }
615 
616 static size_t vrf_nl_getsize(const struct net_device *dev)
617 {
618 	return nla_total_size(sizeof(u32));  /* IFLA_VRF_TABLE */
619 }
620 
621 static int vrf_fillinfo(struct sk_buff *skb,
622 			const struct net_device *dev)
623 {
624 	struct net_vrf *vrf = netdev_priv(dev);
625 
626 	return nla_put_u32(skb, IFLA_VRF_TABLE, vrf->tb_id);
627 }
628 
629 static const struct nla_policy vrf_nl_policy[IFLA_VRF_MAX + 1] = {
630 	[IFLA_VRF_TABLE] = { .type = NLA_U32 },
631 };
632 
633 static struct rtnl_link_ops vrf_link_ops __read_mostly = {
634 	.kind		= DRV_NAME,
635 	.priv_size	= sizeof(struct net_vrf),
636 
637 	.get_size	= vrf_nl_getsize,
638 	.policy		= vrf_nl_policy,
639 	.validate	= vrf_validate,
640 	.fill_info	= vrf_fillinfo,
641 
642 	.newlink	= vrf_newlink,
643 	.dellink	= vrf_dellink,
644 	.setup		= vrf_setup,
645 	.maxtype	= IFLA_VRF_MAX,
646 };
647 
648 static int vrf_device_event(struct notifier_block *unused,
649 			    unsigned long event, void *ptr)
650 {
651 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
652 
653 	/* only care about unregister events to drop slave references */
654 	if (event == NETDEV_UNREGISTER) {
655 		struct net_vrf_dev *vrf_ptr = rtnl_dereference(dev->vrf_ptr);
656 		struct net_device *vrf_dev;
657 
658 		if (!vrf_ptr || netif_is_vrf(dev))
659 			goto out;
660 
661 		vrf_dev = netdev_master_upper_dev_get(dev);
662 		vrf_del_slave(vrf_dev, dev);
663 	}
664 out:
665 	return NOTIFY_DONE;
666 }
667 
668 static struct notifier_block vrf_notifier_block __read_mostly = {
669 	.notifier_call = vrf_device_event,
670 };
671 
672 static int __init vrf_init_module(void)
673 {
674 	int rc;
675 
676 	vrf_dst_ops.kmem_cachep =
677 		kmem_cache_create("vrf_ip_dst_cache",
678 				  sizeof(struct rtable), 0,
679 				  SLAB_HWCACHE_ALIGN,
680 				  NULL);
681 
682 	if (!vrf_dst_ops.kmem_cachep)
683 		return -ENOMEM;
684 
685 	register_netdevice_notifier(&vrf_notifier_block);
686 
687 	rc = rtnl_link_register(&vrf_link_ops);
688 	if (rc < 0)
689 		goto error;
690 
691 	return 0;
692 
693 error:
694 	unregister_netdevice_notifier(&vrf_notifier_block);
695 	kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
696 	return rc;
697 }
698 
699 static void __exit vrf_cleanup_module(void)
700 {
701 	rtnl_link_unregister(&vrf_link_ops);
702 	unregister_netdevice_notifier(&vrf_notifier_block);
703 	kmem_cache_destroy(vrf_dst_ops.kmem_cachep);
704 }
705 
706 module_init(vrf_init_module);
707 module_exit(vrf_cleanup_module);
708 MODULE_AUTHOR("Shrijeet Mukherjee, David Ahern");
709 MODULE_DESCRIPTION("Device driver to instantiate VRF domains");
710 MODULE_LICENSE("GPL");
711 MODULE_ALIAS_RTNL_LINK(DRV_NAME);
712 MODULE_VERSION(DRV_VERSION);
713