xref: /linux/net/mpls/af_mpls.c (revision aec499c75cf8e0b599be4d559e6922b613085f8f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/types.h>
3 #include <linux/skbuff.h>
4 #include <linux/socket.h>
5 #include <linux/sysctl.h>
6 #include <linux/net.h>
7 #include <linux/module.h>
8 #include <linux/if_arp.h>
9 #include <linux/ipv6.h>
10 #include <linux/mpls.h>
11 #include <linux/netconf.h>
12 #include <linux/nospec.h>
13 #include <linux/vmalloc.h>
14 #include <linux/percpu.h>
15 #include <net/ip.h>
16 #include <net/dst.h>
17 #include <net/sock.h>
18 #include <net/arp.h>
19 #include <net/ip_fib.h>
20 #include <net/netevent.h>
21 #include <net/ip_tunnels.h>
22 #include <net/netns/generic.h>
23 #if IS_ENABLED(CONFIG_IPV6)
24 #include <net/ipv6.h>
25 #endif
26 #include <net/ipv6_stubs.h>
27 #include <net/rtnh.h>
28 #include "internal.h"
29 
30 /* max memory we will use for mpls_route */
31 #define MAX_MPLS_ROUTE_MEM	4096
32 
33 /* Maximum number of labels to look ahead at when selecting a path of
34  * a multipath route
35  */
36 #define MAX_MP_SELECT_LABELS 4
37 
38 #define MPLS_NEIGH_TABLE_UNSPEC (NEIGH_LINK_TABLE + 1)
39 
40 static int label_limit = (1 << 20) - 1;
41 static int ttl_max = 255;
42 
43 #if IS_ENABLED(CONFIG_NET_IP_TUNNEL)
44 static size_t ipgre_mpls_encap_hlen(struct ip_tunnel_encap *e)
45 {
46 	return sizeof(struct mpls_shim_hdr);
47 }
48 
49 static const struct ip_tunnel_encap_ops mpls_iptun_ops = {
50 	.encap_hlen	= ipgre_mpls_encap_hlen,
51 };
52 
53 static int ipgre_tunnel_encap_add_mpls_ops(void)
54 {
55 	return ip_tunnel_encap_add_ops(&mpls_iptun_ops, TUNNEL_ENCAP_MPLS);
56 }
57 
58 static void ipgre_tunnel_encap_del_mpls_ops(void)
59 {
60 	ip_tunnel_encap_del_ops(&mpls_iptun_ops, TUNNEL_ENCAP_MPLS);
61 }
62 #else
63 static int ipgre_tunnel_encap_add_mpls_ops(void)
64 {
65 	return 0;
66 }
67 
68 static void ipgre_tunnel_encap_del_mpls_ops(void)
69 {
70 }
71 #endif
72 
73 static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
74 		       struct nlmsghdr *nlh, struct net *net, u32 portid,
75 		       unsigned int nlm_flags);
76 
77 static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned index)
78 {
79 	struct mpls_route *rt = NULL;
80 
81 	if (index < net->mpls.platform_labels) {
82 		struct mpls_route __rcu **platform_label =
83 			rcu_dereference(net->mpls.platform_label);
84 		rt = rcu_dereference(platform_label[index]);
85 	}
86 	return rt;
87 }
88 
89 bool mpls_output_possible(const struct net_device *dev)
90 {
91 	return dev && (dev->flags & IFF_UP) && netif_carrier_ok(dev);
92 }
93 EXPORT_SYMBOL_GPL(mpls_output_possible);
94 
95 static u8 *__mpls_nh_via(struct mpls_route *rt, struct mpls_nh *nh)
96 {
97 	return (u8 *)nh + rt->rt_via_offset;
98 }
99 
100 static const u8 *mpls_nh_via(const struct mpls_route *rt,
101 			     const struct mpls_nh *nh)
102 {
103 	return __mpls_nh_via((struct mpls_route *)rt, (struct mpls_nh *)nh);
104 }
105 
106 static unsigned int mpls_nh_header_size(const struct mpls_nh *nh)
107 {
108 	/* The size of the layer 2.5 labels to be added for this route */
109 	return nh->nh_labels * sizeof(struct mpls_shim_hdr);
110 }
111 
112 unsigned int mpls_dev_mtu(const struct net_device *dev)
113 {
114 	/* The amount of data the layer 2 frame can hold */
115 	return dev->mtu;
116 }
117 EXPORT_SYMBOL_GPL(mpls_dev_mtu);
118 
119 bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
120 {
121 	if (skb->len <= mtu)
122 		return false;
123 
124 	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
125 		return false;
126 
127 	return true;
128 }
129 EXPORT_SYMBOL_GPL(mpls_pkt_too_big);
130 
131 void mpls_stats_inc_outucastpkts(struct net_device *dev,
132 				 const struct sk_buff *skb)
133 {
134 	struct mpls_dev *mdev;
135 
136 	if (skb->protocol == htons(ETH_P_MPLS_UC)) {
137 		mdev = mpls_dev_get(dev);
138 		if (mdev)
139 			MPLS_INC_STATS_LEN(mdev, skb->len,
140 					   tx_packets,
141 					   tx_bytes);
142 	} else if (skb->protocol == htons(ETH_P_IP)) {
143 		IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len);
144 #if IS_ENABLED(CONFIG_IPV6)
145 	} else if (skb->protocol == htons(ETH_P_IPV6)) {
146 		struct inet6_dev *in6dev = __in6_dev_get(dev);
147 
148 		if (in6dev)
149 			IP6_UPD_PO_STATS(dev_net(dev), in6dev,
150 					 IPSTATS_MIB_OUT, skb->len);
151 #endif
152 	}
153 }
154 EXPORT_SYMBOL_GPL(mpls_stats_inc_outucastpkts);
155 
156 static u32 mpls_multipath_hash(struct mpls_route *rt, struct sk_buff *skb)
157 {
158 	struct mpls_entry_decoded dec;
159 	unsigned int mpls_hdr_len = 0;
160 	struct mpls_shim_hdr *hdr;
161 	bool eli_seen = false;
162 	int label_index;
163 	u32 hash = 0;
164 
165 	for (label_index = 0; label_index < MAX_MP_SELECT_LABELS;
166 	     label_index++) {
167 		mpls_hdr_len += sizeof(*hdr);
168 		if (!pskb_may_pull(skb, mpls_hdr_len))
169 			break;
170 
171 		/* Read and decode the current label */
172 		hdr = mpls_hdr(skb) + label_index;
173 		dec = mpls_entry_decode(hdr);
174 
175 		/* RFC6790 - reserved labels MUST NOT be used as keys
176 		 * for the load-balancing function
177 		 */
178 		if (likely(dec.label >= MPLS_LABEL_FIRST_UNRESERVED)) {
179 			hash = jhash_1word(dec.label, hash);
180 
181 			/* The entropy label follows the entropy label
182 			 * indicator, so this means that the entropy
183 			 * label was just added to the hash - no need to
184 			 * go any deeper either in the label stack or in the
185 			 * payload
186 			 */
187 			if (eli_seen)
188 				break;
189 		} else if (dec.label == MPLS_LABEL_ENTROPY) {
190 			eli_seen = true;
191 		}
192 
193 		if (!dec.bos)
194 			continue;
195 
196 		/* found bottom label; does skb have room for a header? */
197 		if (pskb_may_pull(skb, mpls_hdr_len + sizeof(struct iphdr))) {
198 			const struct iphdr *v4hdr;
199 
200 			v4hdr = (const struct iphdr *)(hdr + 1);
201 			if (v4hdr->version == 4) {
202 				hash = jhash_3words(ntohl(v4hdr->saddr),
203 						    ntohl(v4hdr->daddr),
204 						    v4hdr->protocol, hash);
205 			} else if (v4hdr->version == 6 &&
206 				   pskb_may_pull(skb, mpls_hdr_len +
207 						 sizeof(struct ipv6hdr))) {
208 				const struct ipv6hdr *v6hdr;
209 
210 				v6hdr = (const struct ipv6hdr *)(hdr + 1);
211 				hash = __ipv6_addr_jhash(&v6hdr->saddr, hash);
212 				hash = __ipv6_addr_jhash(&v6hdr->daddr, hash);
213 				hash = jhash_1word(v6hdr->nexthdr, hash);
214 			}
215 		}
216 
217 		break;
218 	}
219 
220 	return hash;
221 }
222 
223 static struct mpls_nh *mpls_get_nexthop(struct mpls_route *rt, u8 index)
224 {
225 	return (struct mpls_nh *)((u8 *)rt->rt_nh + index * rt->rt_nh_size);
226 }
227 
228 /* number of alive nexthops (rt->rt_nhn_alive) and the flags for
229  * a next hop (nh->nh_flags) are modified by netdev event handlers.
230  * Since those fields can change at any moment, use READ_ONCE to
231  * access both.
232  */
233 static const struct mpls_nh *mpls_select_multipath(struct mpls_route *rt,
234 						   struct sk_buff *skb)
235 {
236 	u32 hash = 0;
237 	int nh_index = 0;
238 	int n = 0;
239 	u8 alive;
240 
241 	/* No need to look further into packet if there's only
242 	 * one path
243 	 */
244 	if (rt->rt_nhn == 1)
245 		return rt->rt_nh;
246 
247 	alive = READ_ONCE(rt->rt_nhn_alive);
248 	if (alive == 0)
249 		return NULL;
250 
251 	hash = mpls_multipath_hash(rt, skb);
252 	nh_index = hash % alive;
253 	if (alive == rt->rt_nhn)
254 		goto out;
255 	for_nexthops(rt) {
256 		unsigned int nh_flags = READ_ONCE(nh->nh_flags);
257 
258 		if (nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
259 			continue;
260 		if (n == nh_index)
261 			return nh;
262 		n++;
263 	} endfor_nexthops(rt);
264 
265 out:
266 	return mpls_get_nexthop(rt, nh_index);
267 }
268 
269 static bool mpls_egress(struct net *net, struct mpls_route *rt,
270 			struct sk_buff *skb, struct mpls_entry_decoded dec)
271 {
272 	enum mpls_payload_type payload_type;
273 	bool success = false;
274 
275 	/* The IPv4 code below accesses through the IPv4 header
276 	 * checksum, which is 12 bytes into the packet.
277 	 * The IPv6 code below accesses through the IPv6 hop limit
278 	 * which is 8 bytes into the packet.
279 	 *
280 	 * For all supported cases there should always be at least 12
281 	 * bytes of packet data present.  The IPv4 header is 20 bytes
282 	 * without options and the IPv6 header is always 40 bytes
283 	 * long.
284 	 */
285 	if (!pskb_may_pull(skb, 12))
286 		return false;
287 
288 	payload_type = rt->rt_payload_type;
289 	if (payload_type == MPT_UNSPEC)
290 		payload_type = ip_hdr(skb)->version;
291 
292 	switch (payload_type) {
293 	case MPT_IPV4: {
294 		struct iphdr *hdr4 = ip_hdr(skb);
295 		u8 new_ttl;
296 		skb->protocol = htons(ETH_P_IP);
297 
298 		/* If propagating TTL, take the decremented TTL from
299 		 * the incoming MPLS header, otherwise decrement the
300 		 * TTL, but only if not 0 to avoid underflow.
301 		 */
302 		if (rt->rt_ttl_propagate == MPLS_TTL_PROP_ENABLED ||
303 		    (rt->rt_ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
304 		     net->mpls.ip_ttl_propagate))
305 			new_ttl = dec.ttl;
306 		else
307 			new_ttl = hdr4->ttl ? hdr4->ttl - 1 : 0;
308 
309 		csum_replace2(&hdr4->check,
310 			      htons(hdr4->ttl << 8),
311 			      htons(new_ttl << 8));
312 		hdr4->ttl = new_ttl;
313 		success = true;
314 		break;
315 	}
316 	case MPT_IPV6: {
317 		struct ipv6hdr *hdr6 = ipv6_hdr(skb);
318 		skb->protocol = htons(ETH_P_IPV6);
319 
320 		/* If propagating TTL, take the decremented TTL from
321 		 * the incoming MPLS header, otherwise decrement the
322 		 * hop limit, but only if not 0 to avoid underflow.
323 		 */
324 		if (rt->rt_ttl_propagate == MPLS_TTL_PROP_ENABLED ||
325 		    (rt->rt_ttl_propagate == MPLS_TTL_PROP_DEFAULT &&
326 		     net->mpls.ip_ttl_propagate))
327 			hdr6->hop_limit = dec.ttl;
328 		else if (hdr6->hop_limit)
329 			hdr6->hop_limit = hdr6->hop_limit - 1;
330 		success = true;
331 		break;
332 	}
333 	case MPT_UNSPEC:
334 		/* Should have decided which protocol it is by now */
335 		break;
336 	}
337 
338 	return success;
339 }
340 
341 static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
342 			struct packet_type *pt, struct net_device *orig_dev)
343 {
344 	struct net *net = dev_net(dev);
345 	struct mpls_shim_hdr *hdr;
346 	const struct mpls_nh *nh;
347 	struct mpls_route *rt;
348 	struct mpls_entry_decoded dec;
349 	struct net_device *out_dev;
350 	struct mpls_dev *out_mdev;
351 	struct mpls_dev *mdev;
352 	unsigned int hh_len;
353 	unsigned int new_header_size;
354 	unsigned int mtu;
355 	int err;
356 
357 	/* Careful this entire function runs inside of an rcu critical section */
358 
359 	mdev = mpls_dev_get(dev);
360 	if (!mdev)
361 		goto drop;
362 
363 	MPLS_INC_STATS_LEN(mdev, skb->len, rx_packets,
364 			   rx_bytes);
365 
366 	if (!mdev->input_enabled) {
367 		MPLS_INC_STATS(mdev, rx_dropped);
368 		goto drop;
369 	}
370 
371 	if (skb->pkt_type != PACKET_HOST)
372 		goto err;
373 
374 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
375 		goto err;
376 
377 	if (!pskb_may_pull(skb, sizeof(*hdr)))
378 		goto err;
379 
380 	skb_dst_drop(skb);
381 
382 	/* Read and decode the label */
383 	hdr = mpls_hdr(skb);
384 	dec = mpls_entry_decode(hdr);
385 
386 	rt = mpls_route_input_rcu(net, dec.label);
387 	if (!rt) {
388 		MPLS_INC_STATS(mdev, rx_noroute);
389 		goto drop;
390 	}
391 
392 	nh = mpls_select_multipath(rt, skb);
393 	if (!nh)
394 		goto err;
395 
396 	/* Pop the label */
397 	skb_pull(skb, sizeof(*hdr));
398 	skb_reset_network_header(skb);
399 
400 	skb_orphan(skb);
401 
402 	if (skb_warn_if_lro(skb))
403 		goto err;
404 
405 	skb_forward_csum(skb);
406 
407 	/* Verify ttl is valid */
408 	if (dec.ttl <= 1)
409 		goto err;
410 
411 	/* Find the output device */
412 	out_dev = nh->nh_dev;
413 	if (!mpls_output_possible(out_dev))
414 		goto tx_err;
415 
416 	/* Verify the destination can hold the packet */
417 	new_header_size = mpls_nh_header_size(nh);
418 	mtu = mpls_dev_mtu(out_dev);
419 	if (mpls_pkt_too_big(skb, mtu - new_header_size))
420 		goto tx_err;
421 
422 	hh_len = LL_RESERVED_SPACE(out_dev);
423 	if (!out_dev->header_ops)
424 		hh_len = 0;
425 
426 	/* Ensure there is enough space for the headers in the skb */
427 	if (skb_cow(skb, hh_len + new_header_size))
428 		goto tx_err;
429 
430 	skb->dev = out_dev;
431 	skb->protocol = htons(ETH_P_MPLS_UC);
432 
433 	dec.ttl -= 1;
434 	if (unlikely(!new_header_size && dec.bos)) {
435 		/* Penultimate hop popping */
436 		if (!mpls_egress(dev_net(out_dev), rt, skb, dec))
437 			goto err;
438 	} else {
439 		bool bos;
440 		int i;
441 		skb_push(skb, new_header_size);
442 		skb_reset_network_header(skb);
443 		/* Push the new labels */
444 		hdr = mpls_hdr(skb);
445 		bos = dec.bos;
446 		for (i = nh->nh_labels - 1; i >= 0; i--) {
447 			hdr[i] = mpls_entry_encode(nh->nh_label[i],
448 						   dec.ttl, 0, bos);
449 			bos = false;
450 		}
451 	}
452 
453 	mpls_stats_inc_outucastpkts(out_dev, skb);
454 
455 	/* If via wasn't specified then send out using device address */
456 	if (nh->nh_via_table == MPLS_NEIGH_TABLE_UNSPEC)
457 		err = neigh_xmit(NEIGH_LINK_TABLE, out_dev,
458 				 out_dev->dev_addr, skb);
459 	else
460 		err = neigh_xmit(nh->nh_via_table, out_dev,
461 				 mpls_nh_via(rt, nh), skb);
462 	if (err)
463 		net_dbg_ratelimited("%s: packet transmission failed: %d\n",
464 				    __func__, err);
465 	return 0;
466 
467 tx_err:
468 	out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;
469 	if (out_mdev)
470 		MPLS_INC_STATS(out_mdev, tx_errors);
471 	goto drop;
472 err:
473 	MPLS_INC_STATS(mdev, rx_errors);
474 drop:
475 	kfree_skb(skb);
476 	return NET_RX_DROP;
477 }
478 
479 static struct packet_type mpls_packet_type __read_mostly = {
480 	.type = cpu_to_be16(ETH_P_MPLS_UC),
481 	.func = mpls_forward,
482 };
483 
484 static const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = {
485 	[RTA_DST]		= { .type = NLA_U32 },
486 	[RTA_OIF]		= { .type = NLA_U32 },
487 	[RTA_TTL_PROPAGATE]	= { .type = NLA_U8 },
488 };
489 
490 struct mpls_route_config {
491 	u32			rc_protocol;
492 	u32			rc_ifindex;
493 	u8			rc_via_table;
494 	u8			rc_via_alen;
495 	u8			rc_via[MAX_VIA_ALEN];
496 	u32			rc_label;
497 	u8			rc_ttl_propagate;
498 	u8			rc_output_labels;
499 	u32			rc_output_label[MAX_NEW_LABELS];
500 	u32			rc_nlflags;
501 	enum mpls_payload_type	rc_payload_type;
502 	struct nl_info		rc_nlinfo;
503 	struct rtnexthop	*rc_mp;
504 	int			rc_mp_len;
505 };
506 
507 /* all nexthops within a route have the same size based on max
508  * number of labels and max via length for a hop
509  */
510 static struct mpls_route *mpls_rt_alloc(u8 num_nh, u8 max_alen, u8 max_labels)
511 {
512 	u8 nh_size = MPLS_NH_SIZE(max_labels, max_alen);
513 	struct mpls_route *rt;
514 	size_t size;
515 
516 	size = sizeof(*rt) + num_nh * nh_size;
517 	if (size > MAX_MPLS_ROUTE_MEM)
518 		return ERR_PTR(-EINVAL);
519 
520 	rt = kzalloc(size, GFP_KERNEL);
521 	if (!rt)
522 		return ERR_PTR(-ENOMEM);
523 
524 	rt->rt_nhn = num_nh;
525 	rt->rt_nhn_alive = num_nh;
526 	rt->rt_nh_size = nh_size;
527 	rt->rt_via_offset = MPLS_NH_VIA_OFF(max_labels);
528 
529 	return rt;
530 }
531 
532 static void mpls_rt_free(struct mpls_route *rt)
533 {
534 	if (rt)
535 		kfree_rcu(rt, rt_rcu);
536 }
537 
538 static void mpls_notify_route(struct net *net, unsigned index,
539 			      struct mpls_route *old, struct mpls_route *new,
540 			      const struct nl_info *info)
541 {
542 	struct nlmsghdr *nlh = info ? info->nlh : NULL;
543 	unsigned portid = info ? info->portid : 0;
544 	int event = new ? RTM_NEWROUTE : RTM_DELROUTE;
545 	struct mpls_route *rt = new ? new : old;
546 	unsigned nlm_flags = (old && new) ? NLM_F_REPLACE : 0;
547 	/* Ignore reserved labels for now */
548 	if (rt && (index >= MPLS_LABEL_FIRST_UNRESERVED))
549 		rtmsg_lfib(event, index, rt, nlh, net, portid, nlm_flags);
550 }
551 
552 static void mpls_route_update(struct net *net, unsigned index,
553 			      struct mpls_route *new,
554 			      const struct nl_info *info)
555 {
556 	struct mpls_route __rcu **platform_label;
557 	struct mpls_route *rt;
558 
559 	ASSERT_RTNL();
560 
561 	platform_label = rtnl_dereference(net->mpls.platform_label);
562 	rt = rtnl_dereference(platform_label[index]);
563 	rcu_assign_pointer(platform_label[index], new);
564 
565 	mpls_notify_route(net, index, rt, new, info);
566 
567 	/* If we removed a route free it now */
568 	mpls_rt_free(rt);
569 }
570 
571 static unsigned find_free_label(struct net *net)
572 {
573 	struct mpls_route __rcu **platform_label;
574 	size_t platform_labels;
575 	unsigned index;
576 
577 	platform_label = rtnl_dereference(net->mpls.platform_label);
578 	platform_labels = net->mpls.platform_labels;
579 	for (index = MPLS_LABEL_FIRST_UNRESERVED; index < platform_labels;
580 	     index++) {
581 		if (!rtnl_dereference(platform_label[index]))
582 			return index;
583 	}
584 	return LABEL_NOT_SPECIFIED;
585 }
586 
587 #if IS_ENABLED(CONFIG_INET)
588 static struct net_device *inet_fib_lookup_dev(struct net *net,
589 					      const void *addr)
590 {
591 	struct net_device *dev;
592 	struct rtable *rt;
593 	struct in_addr daddr;
594 
595 	memcpy(&daddr, addr, sizeof(struct in_addr));
596 	rt = ip_route_output(net, daddr.s_addr, 0, 0, 0);
597 	if (IS_ERR(rt))
598 		return ERR_CAST(rt);
599 
600 	dev = rt->dst.dev;
601 	dev_hold(dev);
602 
603 	ip_rt_put(rt);
604 
605 	return dev;
606 }
607 #else
608 static struct net_device *inet_fib_lookup_dev(struct net *net,
609 					      const void *addr)
610 {
611 	return ERR_PTR(-EAFNOSUPPORT);
612 }
613 #endif
614 
615 #if IS_ENABLED(CONFIG_IPV6)
616 static struct net_device *inet6_fib_lookup_dev(struct net *net,
617 					       const void *addr)
618 {
619 	struct net_device *dev;
620 	struct dst_entry *dst;
621 	struct flowi6 fl6;
622 
623 	if (!ipv6_stub)
624 		return ERR_PTR(-EAFNOSUPPORT);
625 
626 	memset(&fl6, 0, sizeof(fl6));
627 	memcpy(&fl6.daddr, addr, sizeof(struct in6_addr));
628 	dst = ipv6_stub->ipv6_dst_lookup_flow(net, NULL, &fl6, NULL);
629 	if (IS_ERR(dst))
630 		return ERR_CAST(dst);
631 
632 	dev = dst->dev;
633 	dev_hold(dev);
634 	dst_release(dst);
635 
636 	return dev;
637 }
638 #else
639 static struct net_device *inet6_fib_lookup_dev(struct net *net,
640 					       const void *addr)
641 {
642 	return ERR_PTR(-EAFNOSUPPORT);
643 }
644 #endif
645 
646 static struct net_device *find_outdev(struct net *net,
647 				      struct mpls_route *rt,
648 				      struct mpls_nh *nh, int oif)
649 {
650 	struct net_device *dev = NULL;
651 
652 	if (!oif) {
653 		switch (nh->nh_via_table) {
654 		case NEIGH_ARP_TABLE:
655 			dev = inet_fib_lookup_dev(net, mpls_nh_via(rt, nh));
656 			break;
657 		case NEIGH_ND_TABLE:
658 			dev = inet6_fib_lookup_dev(net, mpls_nh_via(rt, nh));
659 			break;
660 		case NEIGH_LINK_TABLE:
661 			break;
662 		}
663 	} else {
664 		dev = dev_get_by_index(net, oif);
665 	}
666 
667 	if (!dev)
668 		return ERR_PTR(-ENODEV);
669 
670 	if (IS_ERR(dev))
671 		return dev;
672 
673 	/* The caller is holding rtnl anyways, so release the dev reference */
674 	dev_put(dev);
675 
676 	return dev;
677 }
678 
679 static int mpls_nh_assign_dev(struct net *net, struct mpls_route *rt,
680 			      struct mpls_nh *nh, int oif)
681 {
682 	struct net_device *dev = NULL;
683 	int err = -ENODEV;
684 
685 	dev = find_outdev(net, rt, nh, oif);
686 	if (IS_ERR(dev)) {
687 		err = PTR_ERR(dev);
688 		dev = NULL;
689 		goto errout;
690 	}
691 
692 	/* Ensure this is a supported device */
693 	err = -EINVAL;
694 	if (!mpls_dev_get(dev))
695 		goto errout;
696 
697 	if ((nh->nh_via_table == NEIGH_LINK_TABLE) &&
698 	    (dev->addr_len != nh->nh_via_alen))
699 		goto errout;
700 
701 	nh->nh_dev = dev;
702 
703 	if (!(dev->flags & IFF_UP)) {
704 		nh->nh_flags |= RTNH_F_DEAD;
705 	} else {
706 		unsigned int flags;
707 
708 		flags = dev_get_flags(dev);
709 		if (!(flags & (IFF_RUNNING | IFF_LOWER_UP)))
710 			nh->nh_flags |= RTNH_F_LINKDOWN;
711 	}
712 
713 	return 0;
714 
715 errout:
716 	return err;
717 }
718 
719 static int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
720 		       u8 via_addr[], struct netlink_ext_ack *extack)
721 {
722 	struct rtvia *via = nla_data(nla);
723 	int err = -EINVAL;
724 	int alen;
725 
726 	if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
727 		NL_SET_ERR_MSG_ATTR(extack, nla,
728 				    "Invalid attribute length for RTA_VIA");
729 		goto errout;
730 	}
731 	alen = nla_len(nla) -
732 			offsetof(struct rtvia, rtvia_addr);
733 	if (alen > MAX_VIA_ALEN) {
734 		NL_SET_ERR_MSG_ATTR(extack, nla,
735 				    "Invalid address length for RTA_VIA");
736 		goto errout;
737 	}
738 
739 	/* Validate the address family */
740 	switch (via->rtvia_family) {
741 	case AF_PACKET:
742 		*via_table = NEIGH_LINK_TABLE;
743 		break;
744 	case AF_INET:
745 		*via_table = NEIGH_ARP_TABLE;
746 		if (alen != 4)
747 			goto errout;
748 		break;
749 	case AF_INET6:
750 		*via_table = NEIGH_ND_TABLE;
751 		if (alen != 16)
752 			goto errout;
753 		break;
754 	default:
755 		/* Unsupported address family */
756 		goto errout;
757 	}
758 
759 	memcpy(via_addr, via->rtvia_addr, alen);
760 	*via_alen = alen;
761 	err = 0;
762 
763 errout:
764 	return err;
765 }
766 
767 static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
768 				  struct mpls_route *rt)
769 {
770 	struct net *net = cfg->rc_nlinfo.nl_net;
771 	struct mpls_nh *nh = rt->rt_nh;
772 	int err;
773 	int i;
774 
775 	if (!nh)
776 		return -ENOMEM;
777 
778 	nh->nh_labels = cfg->rc_output_labels;
779 	for (i = 0; i < nh->nh_labels; i++)
780 		nh->nh_label[i] = cfg->rc_output_label[i];
781 
782 	nh->nh_via_table = cfg->rc_via_table;
783 	memcpy(__mpls_nh_via(rt, nh), cfg->rc_via, cfg->rc_via_alen);
784 	nh->nh_via_alen = cfg->rc_via_alen;
785 
786 	err = mpls_nh_assign_dev(net, rt, nh, cfg->rc_ifindex);
787 	if (err)
788 		goto errout;
789 
790 	if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
791 		rt->rt_nhn_alive--;
792 
793 	return 0;
794 
795 errout:
796 	return err;
797 }
798 
799 static int mpls_nh_build(struct net *net, struct mpls_route *rt,
800 			 struct mpls_nh *nh, int oif, struct nlattr *via,
801 			 struct nlattr *newdst, u8 max_labels,
802 			 struct netlink_ext_ack *extack)
803 {
804 	int err = -ENOMEM;
805 
806 	if (!nh)
807 		goto errout;
808 
809 	if (newdst) {
810 		err = nla_get_labels(newdst, max_labels, &nh->nh_labels,
811 				     nh->nh_label, extack);
812 		if (err)
813 			goto errout;
814 	}
815 
816 	if (via) {
817 		err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
818 				  __mpls_nh_via(rt, nh), extack);
819 		if (err)
820 			goto errout;
821 	} else {
822 		nh->nh_via_table = MPLS_NEIGH_TABLE_UNSPEC;
823 	}
824 
825 	err = mpls_nh_assign_dev(net, rt, nh, oif);
826 	if (err)
827 		goto errout;
828 
829 	return 0;
830 
831 errout:
832 	return err;
833 }
834 
835 static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len,
836 			      u8 cfg_via_alen, u8 *max_via_alen,
837 			      u8 *max_labels)
838 {
839 	int remaining = len;
840 	u8 nhs = 0;
841 
842 	*max_via_alen = 0;
843 	*max_labels = 0;
844 
845 	while (rtnh_ok(rtnh, remaining)) {
846 		struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
847 		int attrlen;
848 		u8 n_labels = 0;
849 
850 		attrlen = rtnh_attrlen(rtnh);
851 		nla = nla_find(attrs, attrlen, RTA_VIA);
852 		if (nla && nla_len(nla) >=
853 		    offsetof(struct rtvia, rtvia_addr)) {
854 			int via_alen = nla_len(nla) -
855 				offsetof(struct rtvia, rtvia_addr);
856 
857 			if (via_alen <= MAX_VIA_ALEN)
858 				*max_via_alen = max_t(u16, *max_via_alen,
859 						      via_alen);
860 		}
861 
862 		nla = nla_find(attrs, attrlen, RTA_NEWDST);
863 		if (nla &&
864 		    nla_get_labels(nla, MAX_NEW_LABELS, &n_labels,
865 				   NULL, NULL) != 0)
866 			return 0;
867 
868 		*max_labels = max_t(u8, *max_labels, n_labels);
869 
870 		/* number of nexthops is tracked by a u8.
871 		 * Check for overflow.
872 		 */
873 		if (nhs == 255)
874 			return 0;
875 		nhs++;
876 
877 		rtnh = rtnh_next(rtnh, &remaining);
878 	}
879 
880 	/* leftover implies invalid nexthop configuration, discard it */
881 	return remaining > 0 ? 0 : nhs;
882 }
883 
884 static int mpls_nh_build_multi(struct mpls_route_config *cfg,
885 			       struct mpls_route *rt, u8 max_labels,
886 			       struct netlink_ext_ack *extack)
887 {
888 	struct rtnexthop *rtnh = cfg->rc_mp;
889 	struct nlattr *nla_via, *nla_newdst;
890 	int remaining = cfg->rc_mp_len;
891 	int err = 0;
892 	u8 nhs = 0;
893 
894 	change_nexthops(rt) {
895 		int attrlen;
896 
897 		nla_via = NULL;
898 		nla_newdst = NULL;
899 
900 		err = -EINVAL;
901 		if (!rtnh_ok(rtnh, remaining))
902 			goto errout;
903 
904 		/* neither weighted multipath nor any flags
905 		 * are supported
906 		 */
907 		if (rtnh->rtnh_hops || rtnh->rtnh_flags)
908 			goto errout;
909 
910 		attrlen = rtnh_attrlen(rtnh);
911 		if (attrlen > 0) {
912 			struct nlattr *attrs = rtnh_attrs(rtnh);
913 
914 			nla_via = nla_find(attrs, attrlen, RTA_VIA);
915 			nla_newdst = nla_find(attrs, attrlen, RTA_NEWDST);
916 		}
917 
918 		err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh,
919 				    rtnh->rtnh_ifindex, nla_via, nla_newdst,
920 				    max_labels, extack);
921 		if (err)
922 			goto errout;
923 
924 		if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
925 			rt->rt_nhn_alive--;
926 
927 		rtnh = rtnh_next(rtnh, &remaining);
928 		nhs++;
929 	} endfor_nexthops(rt);
930 
931 	rt->rt_nhn = nhs;
932 
933 	return 0;
934 
935 errout:
936 	return err;
937 }
938 
939 static bool mpls_label_ok(struct net *net, unsigned int *index,
940 			  struct netlink_ext_ack *extack)
941 {
942 	bool is_ok = true;
943 
944 	/* Reserved labels may not be set */
945 	if (*index < MPLS_LABEL_FIRST_UNRESERVED) {
946 		NL_SET_ERR_MSG(extack,
947 			       "Invalid label - must be MPLS_LABEL_FIRST_UNRESERVED or higher");
948 		is_ok = false;
949 	}
950 
951 	/* The full 20 bit range may not be supported. */
952 	if (is_ok && *index >= net->mpls.platform_labels) {
953 		NL_SET_ERR_MSG(extack,
954 			       "Label >= configured maximum in platform_labels");
955 		is_ok = false;
956 	}
957 
958 	*index = array_index_nospec(*index, net->mpls.platform_labels);
959 	return is_ok;
960 }
961 
962 static int mpls_route_add(struct mpls_route_config *cfg,
963 			  struct netlink_ext_ack *extack)
964 {
965 	struct mpls_route __rcu **platform_label;
966 	struct net *net = cfg->rc_nlinfo.nl_net;
967 	struct mpls_route *rt, *old;
968 	int err = -EINVAL;
969 	u8 max_via_alen;
970 	unsigned index;
971 	u8 max_labels;
972 	u8 nhs;
973 
974 	index = cfg->rc_label;
975 
976 	/* If a label was not specified during insert pick one */
977 	if ((index == LABEL_NOT_SPECIFIED) &&
978 	    (cfg->rc_nlflags & NLM_F_CREATE)) {
979 		index = find_free_label(net);
980 	}
981 
982 	if (!mpls_label_ok(net, &index, extack))
983 		goto errout;
984 
985 	/* Append makes no sense with mpls */
986 	err = -EOPNOTSUPP;
987 	if (cfg->rc_nlflags & NLM_F_APPEND) {
988 		NL_SET_ERR_MSG(extack, "MPLS does not support route append");
989 		goto errout;
990 	}
991 
992 	err = -EEXIST;
993 	platform_label = rtnl_dereference(net->mpls.platform_label);
994 	old = rtnl_dereference(platform_label[index]);
995 	if ((cfg->rc_nlflags & NLM_F_EXCL) && old)
996 		goto errout;
997 
998 	err = -EEXIST;
999 	if (!(cfg->rc_nlflags & NLM_F_REPLACE) && old)
1000 		goto errout;
1001 
1002 	err = -ENOENT;
1003 	if (!(cfg->rc_nlflags & NLM_F_CREATE) && !old)
1004 		goto errout;
1005 
1006 	err = -EINVAL;
1007 	if (cfg->rc_mp) {
1008 		nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len,
1009 					  cfg->rc_via_alen, &max_via_alen,
1010 					  &max_labels);
1011 	} else {
1012 		max_via_alen = cfg->rc_via_alen;
1013 		max_labels = cfg->rc_output_labels;
1014 		nhs = 1;
1015 	}
1016 
1017 	if (nhs == 0) {
1018 		NL_SET_ERR_MSG(extack, "Route does not contain a nexthop");
1019 		goto errout;
1020 	}
1021 
1022 	rt = mpls_rt_alloc(nhs, max_via_alen, max_labels);
1023 	if (IS_ERR(rt)) {
1024 		err = PTR_ERR(rt);
1025 		goto errout;
1026 	}
1027 
1028 	rt->rt_protocol = cfg->rc_protocol;
1029 	rt->rt_payload_type = cfg->rc_payload_type;
1030 	rt->rt_ttl_propagate = cfg->rc_ttl_propagate;
1031 
1032 	if (cfg->rc_mp)
1033 		err = mpls_nh_build_multi(cfg, rt, max_labels, extack);
1034 	else
1035 		err = mpls_nh_build_from_cfg(cfg, rt);
1036 	if (err)
1037 		goto freert;
1038 
1039 	mpls_route_update(net, index, rt, &cfg->rc_nlinfo);
1040 
1041 	return 0;
1042 
1043 freert:
1044 	mpls_rt_free(rt);
1045 errout:
1046 	return err;
1047 }
1048 
1049 static int mpls_route_del(struct mpls_route_config *cfg,
1050 			  struct netlink_ext_ack *extack)
1051 {
1052 	struct net *net = cfg->rc_nlinfo.nl_net;
1053 	unsigned index;
1054 	int err = -EINVAL;
1055 
1056 	index = cfg->rc_label;
1057 
1058 	if (!mpls_label_ok(net, &index, extack))
1059 		goto errout;
1060 
1061 	mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
1062 
1063 	err = 0;
1064 errout:
1065 	return err;
1066 }
1067 
1068 static void mpls_get_stats(struct mpls_dev *mdev,
1069 			   struct mpls_link_stats *stats)
1070 {
1071 	struct mpls_pcpu_stats *p;
1072 	int i;
1073 
1074 	memset(stats, 0, sizeof(*stats));
1075 
1076 	for_each_possible_cpu(i) {
1077 		struct mpls_link_stats local;
1078 		unsigned int start;
1079 
1080 		p = per_cpu_ptr(mdev->stats, i);
1081 		do {
1082 			start = u64_stats_fetch_begin(&p->syncp);
1083 			local = p->stats;
1084 		} while (u64_stats_fetch_retry(&p->syncp, start));
1085 
1086 		stats->rx_packets	+= local.rx_packets;
1087 		stats->rx_bytes		+= local.rx_bytes;
1088 		stats->tx_packets	+= local.tx_packets;
1089 		stats->tx_bytes		+= local.tx_bytes;
1090 		stats->rx_errors	+= local.rx_errors;
1091 		stats->tx_errors	+= local.tx_errors;
1092 		stats->rx_dropped	+= local.rx_dropped;
1093 		stats->tx_dropped	+= local.tx_dropped;
1094 		stats->rx_noroute	+= local.rx_noroute;
1095 	}
1096 }
1097 
1098 static int mpls_fill_stats_af(struct sk_buff *skb,
1099 			      const struct net_device *dev)
1100 {
1101 	struct mpls_link_stats *stats;
1102 	struct mpls_dev *mdev;
1103 	struct nlattr *nla;
1104 
1105 	mdev = mpls_dev_get(dev);
1106 	if (!mdev)
1107 		return -ENODATA;
1108 
1109 	nla = nla_reserve_64bit(skb, MPLS_STATS_LINK,
1110 				sizeof(struct mpls_link_stats),
1111 				MPLS_STATS_UNSPEC);
1112 	if (!nla)
1113 		return -EMSGSIZE;
1114 
1115 	stats = nla_data(nla);
1116 	mpls_get_stats(mdev, stats);
1117 
1118 	return 0;
1119 }
1120 
1121 static size_t mpls_get_stats_af_size(const struct net_device *dev)
1122 {
1123 	struct mpls_dev *mdev;
1124 
1125 	mdev = mpls_dev_get(dev);
1126 	if (!mdev)
1127 		return 0;
1128 
1129 	return nla_total_size_64bit(sizeof(struct mpls_link_stats));
1130 }
1131 
1132 static int mpls_netconf_fill_devconf(struct sk_buff *skb, struct mpls_dev *mdev,
1133 				     u32 portid, u32 seq, int event,
1134 				     unsigned int flags, int type)
1135 {
1136 	struct nlmsghdr  *nlh;
1137 	struct netconfmsg *ncm;
1138 	bool all = false;
1139 
1140 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct netconfmsg),
1141 			flags);
1142 	if (!nlh)
1143 		return -EMSGSIZE;
1144 
1145 	if (type == NETCONFA_ALL)
1146 		all = true;
1147 
1148 	ncm = nlmsg_data(nlh);
1149 	ncm->ncm_family = AF_MPLS;
1150 
1151 	if (nla_put_s32(skb, NETCONFA_IFINDEX, mdev->dev->ifindex) < 0)
1152 		goto nla_put_failure;
1153 
1154 	if ((all || type == NETCONFA_INPUT) &&
1155 	    nla_put_s32(skb, NETCONFA_INPUT,
1156 			mdev->input_enabled) < 0)
1157 		goto nla_put_failure;
1158 
1159 	nlmsg_end(skb, nlh);
1160 	return 0;
1161 
1162 nla_put_failure:
1163 	nlmsg_cancel(skb, nlh);
1164 	return -EMSGSIZE;
1165 }
1166 
1167 static int mpls_netconf_msgsize_devconf(int type)
1168 {
1169 	int size = NLMSG_ALIGN(sizeof(struct netconfmsg))
1170 			+ nla_total_size(4); /* NETCONFA_IFINDEX */
1171 	bool all = false;
1172 
1173 	if (type == NETCONFA_ALL)
1174 		all = true;
1175 
1176 	if (all || type == NETCONFA_INPUT)
1177 		size += nla_total_size(4);
1178 
1179 	return size;
1180 }
1181 
1182 static void mpls_netconf_notify_devconf(struct net *net, int event,
1183 					int type, struct mpls_dev *mdev)
1184 {
1185 	struct sk_buff *skb;
1186 	int err = -ENOBUFS;
1187 
1188 	skb = nlmsg_new(mpls_netconf_msgsize_devconf(type), GFP_KERNEL);
1189 	if (!skb)
1190 		goto errout;
1191 
1192 	err = mpls_netconf_fill_devconf(skb, mdev, 0, 0, event, 0, type);
1193 	if (err < 0) {
1194 		/* -EMSGSIZE implies BUG in mpls_netconf_msgsize_devconf() */
1195 		WARN_ON(err == -EMSGSIZE);
1196 		kfree_skb(skb);
1197 		goto errout;
1198 	}
1199 
1200 	rtnl_notify(skb, net, 0, RTNLGRP_MPLS_NETCONF, NULL, GFP_KERNEL);
1201 	return;
1202 errout:
1203 	if (err < 0)
1204 		rtnl_set_sk_err(net, RTNLGRP_MPLS_NETCONF, err);
1205 }
1206 
1207 static const struct nla_policy devconf_mpls_policy[NETCONFA_MAX + 1] = {
1208 	[NETCONFA_IFINDEX]	= { .len = sizeof(int) },
1209 };
1210 
1211 static int mpls_netconf_valid_get_req(struct sk_buff *skb,
1212 				      const struct nlmsghdr *nlh,
1213 				      struct nlattr **tb,
1214 				      struct netlink_ext_ack *extack)
1215 {
1216 	int i, err;
1217 
1218 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(struct netconfmsg))) {
1219 		NL_SET_ERR_MSG_MOD(extack,
1220 				   "Invalid header for netconf get request");
1221 		return -EINVAL;
1222 	}
1223 
1224 	if (!netlink_strict_get_check(skb))
1225 		return nlmsg_parse_deprecated(nlh, sizeof(struct netconfmsg),
1226 					      tb, NETCONFA_MAX,
1227 					      devconf_mpls_policy, extack);
1228 
1229 	err = nlmsg_parse_deprecated_strict(nlh, sizeof(struct netconfmsg),
1230 					    tb, NETCONFA_MAX,
1231 					    devconf_mpls_policy, extack);
1232 	if (err)
1233 		return err;
1234 
1235 	for (i = 0; i <= NETCONFA_MAX; i++) {
1236 		if (!tb[i])
1237 			continue;
1238 
1239 		switch (i) {
1240 		case NETCONFA_IFINDEX:
1241 			break;
1242 		default:
1243 			NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in netconf get request");
1244 			return -EINVAL;
1245 		}
1246 	}
1247 
1248 	return 0;
1249 }
1250 
1251 static int mpls_netconf_get_devconf(struct sk_buff *in_skb,
1252 				    struct nlmsghdr *nlh,
1253 				    struct netlink_ext_ack *extack)
1254 {
1255 	struct net *net = sock_net(in_skb->sk);
1256 	struct nlattr *tb[NETCONFA_MAX + 1];
1257 	struct net_device *dev;
1258 	struct mpls_dev *mdev;
1259 	struct sk_buff *skb;
1260 	int ifindex;
1261 	int err;
1262 
1263 	err = mpls_netconf_valid_get_req(in_skb, nlh, tb, extack);
1264 	if (err < 0)
1265 		goto errout;
1266 
1267 	err = -EINVAL;
1268 	if (!tb[NETCONFA_IFINDEX])
1269 		goto errout;
1270 
1271 	ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]);
1272 	dev = __dev_get_by_index(net, ifindex);
1273 	if (!dev)
1274 		goto errout;
1275 
1276 	mdev = mpls_dev_get(dev);
1277 	if (!mdev)
1278 		goto errout;
1279 
1280 	err = -ENOBUFS;
1281 	skb = nlmsg_new(mpls_netconf_msgsize_devconf(NETCONFA_ALL), GFP_KERNEL);
1282 	if (!skb)
1283 		goto errout;
1284 
1285 	err = mpls_netconf_fill_devconf(skb, mdev,
1286 					NETLINK_CB(in_skb).portid,
1287 					nlh->nlmsg_seq, RTM_NEWNETCONF, 0,
1288 					NETCONFA_ALL);
1289 	if (err < 0) {
1290 		/* -EMSGSIZE implies BUG in mpls_netconf_msgsize_devconf() */
1291 		WARN_ON(err == -EMSGSIZE);
1292 		kfree_skb(skb);
1293 		goto errout;
1294 	}
1295 	err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
1296 errout:
1297 	return err;
1298 }
1299 
1300 static int mpls_netconf_dump_devconf(struct sk_buff *skb,
1301 				     struct netlink_callback *cb)
1302 {
1303 	const struct nlmsghdr *nlh = cb->nlh;
1304 	struct net *net = sock_net(skb->sk);
1305 	struct hlist_head *head;
1306 	struct net_device *dev;
1307 	struct mpls_dev *mdev;
1308 	int idx, s_idx;
1309 	int h, s_h;
1310 
1311 	if (cb->strict_check) {
1312 		struct netlink_ext_ack *extack = cb->extack;
1313 		struct netconfmsg *ncm;
1314 
1315 		if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*ncm))) {
1316 			NL_SET_ERR_MSG_MOD(extack, "Invalid header for netconf dump request");
1317 			return -EINVAL;
1318 		}
1319 
1320 		if (nlmsg_attrlen(nlh, sizeof(*ncm))) {
1321 			NL_SET_ERR_MSG_MOD(extack, "Invalid data after header in netconf dump request");
1322 			return -EINVAL;
1323 		}
1324 	}
1325 
1326 	s_h = cb->args[0];
1327 	s_idx = idx = cb->args[1];
1328 
1329 	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
1330 		idx = 0;
1331 		head = &net->dev_index_head[h];
1332 		rcu_read_lock();
1333 		cb->seq = net->dev_base_seq;
1334 		hlist_for_each_entry_rcu(dev, head, index_hlist) {
1335 			if (idx < s_idx)
1336 				goto cont;
1337 			mdev = mpls_dev_get(dev);
1338 			if (!mdev)
1339 				goto cont;
1340 			if (mpls_netconf_fill_devconf(skb, mdev,
1341 						      NETLINK_CB(cb->skb).portid,
1342 						      nlh->nlmsg_seq,
1343 						      RTM_NEWNETCONF,
1344 						      NLM_F_MULTI,
1345 						      NETCONFA_ALL) < 0) {
1346 				rcu_read_unlock();
1347 				goto done;
1348 			}
1349 			nl_dump_check_consistent(cb, nlmsg_hdr(skb));
1350 cont:
1351 			idx++;
1352 		}
1353 		rcu_read_unlock();
1354 	}
1355 done:
1356 	cb->args[0] = h;
1357 	cb->args[1] = idx;
1358 
1359 	return skb->len;
1360 }
1361 
1362 #define MPLS_PERDEV_SYSCTL_OFFSET(field)	\
1363 	(&((struct mpls_dev *)0)->field)
1364 
1365 static int mpls_conf_proc(struct ctl_table *ctl, int write,
1366 			  void *buffer, size_t *lenp, loff_t *ppos)
1367 {
1368 	int oval = *(int *)ctl->data;
1369 	int ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
1370 
1371 	if (write) {
1372 		struct mpls_dev *mdev = ctl->extra1;
1373 		int i = (int *)ctl->data - (int *)mdev;
1374 		struct net *net = ctl->extra2;
1375 		int val = *(int *)ctl->data;
1376 
1377 		if (i == offsetof(struct mpls_dev, input_enabled) &&
1378 		    val != oval) {
1379 			mpls_netconf_notify_devconf(net, RTM_NEWNETCONF,
1380 						    NETCONFA_INPUT, mdev);
1381 		}
1382 	}
1383 
1384 	return ret;
1385 }
1386 
1387 static const struct ctl_table mpls_dev_table[] = {
1388 	{
1389 		.procname	= "input",
1390 		.maxlen		= sizeof(int),
1391 		.mode		= 0644,
1392 		.proc_handler	= mpls_conf_proc,
1393 		.data		= MPLS_PERDEV_SYSCTL_OFFSET(input_enabled),
1394 	},
1395 	{ }
1396 };
1397 
1398 static int mpls_dev_sysctl_register(struct net_device *dev,
1399 				    struct mpls_dev *mdev)
1400 {
1401 	char path[sizeof("net/mpls/conf/") + IFNAMSIZ];
1402 	struct net *net = dev_net(dev);
1403 	struct ctl_table *table;
1404 	int i;
1405 
1406 	table = kmemdup(&mpls_dev_table, sizeof(mpls_dev_table), GFP_KERNEL);
1407 	if (!table)
1408 		goto out;
1409 
1410 	/* Table data contains only offsets relative to the base of
1411 	 * the mdev at this point, so make them absolute.
1412 	 */
1413 	for (i = 0; i < ARRAY_SIZE(mpls_dev_table); i++) {
1414 		table[i].data = (char *)mdev + (uintptr_t)table[i].data;
1415 		table[i].extra1 = mdev;
1416 		table[i].extra2 = net;
1417 	}
1418 
1419 	snprintf(path, sizeof(path), "net/mpls/conf/%s", dev->name);
1420 
1421 	mdev->sysctl = register_net_sysctl(net, path, table);
1422 	if (!mdev->sysctl)
1423 		goto free;
1424 
1425 	mpls_netconf_notify_devconf(net, RTM_NEWNETCONF, NETCONFA_ALL, mdev);
1426 	return 0;
1427 
1428 free:
1429 	kfree(table);
1430 out:
1431 	return -ENOBUFS;
1432 }
1433 
1434 static void mpls_dev_sysctl_unregister(struct net_device *dev,
1435 				       struct mpls_dev *mdev)
1436 {
1437 	struct net *net = dev_net(dev);
1438 	struct ctl_table *table;
1439 
1440 	table = mdev->sysctl->ctl_table_arg;
1441 	unregister_net_sysctl_table(mdev->sysctl);
1442 	kfree(table);
1443 
1444 	mpls_netconf_notify_devconf(net, RTM_DELNETCONF, 0, mdev);
1445 }
1446 
1447 static struct mpls_dev *mpls_add_dev(struct net_device *dev)
1448 {
1449 	struct mpls_dev *mdev;
1450 	int err = -ENOMEM;
1451 	int i;
1452 
1453 	ASSERT_RTNL();
1454 
1455 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
1456 	if (!mdev)
1457 		return ERR_PTR(err);
1458 
1459 	mdev->stats = alloc_percpu(struct mpls_pcpu_stats);
1460 	if (!mdev->stats)
1461 		goto free;
1462 
1463 	for_each_possible_cpu(i) {
1464 		struct mpls_pcpu_stats *mpls_stats;
1465 
1466 		mpls_stats = per_cpu_ptr(mdev->stats, i);
1467 		u64_stats_init(&mpls_stats->syncp);
1468 	}
1469 
1470 	mdev->dev = dev;
1471 
1472 	err = mpls_dev_sysctl_register(dev, mdev);
1473 	if (err)
1474 		goto free;
1475 
1476 	rcu_assign_pointer(dev->mpls_ptr, mdev);
1477 
1478 	return mdev;
1479 
1480 free:
1481 	free_percpu(mdev->stats);
1482 	kfree(mdev);
1483 	return ERR_PTR(err);
1484 }
1485 
1486 static void mpls_dev_destroy_rcu(struct rcu_head *head)
1487 {
1488 	struct mpls_dev *mdev = container_of(head, struct mpls_dev, rcu);
1489 
1490 	free_percpu(mdev->stats);
1491 	kfree(mdev);
1492 }
1493 
1494 static int mpls_ifdown(struct net_device *dev, int event)
1495 {
1496 	struct mpls_route __rcu **platform_label;
1497 	struct net *net = dev_net(dev);
1498 	unsigned index;
1499 
1500 	platform_label = rtnl_dereference(net->mpls.platform_label);
1501 	for (index = 0; index < net->mpls.platform_labels; index++) {
1502 		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
1503 		bool nh_del = false;
1504 		u8 alive = 0;
1505 
1506 		if (!rt)
1507 			continue;
1508 
1509 		if (event == NETDEV_UNREGISTER) {
1510 			u8 deleted = 0;
1511 
1512 			for_nexthops(rt) {
1513 				if (!nh->nh_dev || nh->nh_dev == dev)
1514 					deleted++;
1515 				if (nh->nh_dev == dev)
1516 					nh_del = true;
1517 			} endfor_nexthops(rt);
1518 
1519 			/* if there are no more nexthops, delete the route */
1520 			if (deleted == rt->rt_nhn) {
1521 				mpls_route_update(net, index, NULL, NULL);
1522 				continue;
1523 			}
1524 
1525 			if (nh_del) {
1526 				size_t size = sizeof(*rt) + rt->rt_nhn *
1527 					rt->rt_nh_size;
1528 				struct mpls_route *orig = rt;
1529 
1530 				rt = kmalloc(size, GFP_KERNEL);
1531 				if (!rt)
1532 					return -ENOMEM;
1533 				memcpy(rt, orig, size);
1534 			}
1535 		}
1536 
1537 		change_nexthops(rt) {
1538 			unsigned int nh_flags = nh->nh_flags;
1539 
1540 			if (nh->nh_dev != dev)
1541 				goto next;
1542 
1543 			switch (event) {
1544 			case NETDEV_DOWN:
1545 			case NETDEV_UNREGISTER:
1546 				nh_flags |= RTNH_F_DEAD;
1547 				fallthrough;
1548 			case NETDEV_CHANGE:
1549 				nh_flags |= RTNH_F_LINKDOWN;
1550 				break;
1551 			}
1552 			if (event == NETDEV_UNREGISTER)
1553 				nh->nh_dev = NULL;
1554 
1555 			if (nh->nh_flags != nh_flags)
1556 				WRITE_ONCE(nh->nh_flags, nh_flags);
1557 next:
1558 			if (!(nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)))
1559 				alive++;
1560 		} endfor_nexthops(rt);
1561 
1562 		WRITE_ONCE(rt->rt_nhn_alive, alive);
1563 
1564 		if (nh_del)
1565 			mpls_route_update(net, index, rt, NULL);
1566 	}
1567 
1568 	return 0;
1569 }
1570 
1571 static void mpls_ifup(struct net_device *dev, unsigned int flags)
1572 {
1573 	struct mpls_route __rcu **platform_label;
1574 	struct net *net = dev_net(dev);
1575 	unsigned index;
1576 	u8 alive;
1577 
1578 	platform_label = rtnl_dereference(net->mpls.platform_label);
1579 	for (index = 0; index < net->mpls.platform_labels; index++) {
1580 		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
1581 
1582 		if (!rt)
1583 			continue;
1584 
1585 		alive = 0;
1586 		change_nexthops(rt) {
1587 			unsigned int nh_flags = nh->nh_flags;
1588 
1589 			if (!(nh_flags & flags)) {
1590 				alive++;
1591 				continue;
1592 			}
1593 			if (nh->nh_dev != dev)
1594 				continue;
1595 			alive++;
1596 			nh_flags &= ~flags;
1597 			WRITE_ONCE(nh->nh_flags, nh_flags);
1598 		} endfor_nexthops(rt);
1599 
1600 		WRITE_ONCE(rt->rt_nhn_alive, alive);
1601 	}
1602 }
1603 
1604 static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
1605 			   void *ptr)
1606 {
1607 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1608 	struct mpls_dev *mdev;
1609 	unsigned int flags;
1610 
1611 	if (event == NETDEV_REGISTER) {
1612 		mdev = mpls_add_dev(dev);
1613 		if (IS_ERR(mdev))
1614 			return notifier_from_errno(PTR_ERR(mdev));
1615 
1616 		return NOTIFY_OK;
1617 	}
1618 
1619 	mdev = mpls_dev_get(dev);
1620 	if (!mdev)
1621 		return NOTIFY_OK;
1622 
1623 	switch (event) {
1624 		int err;
1625 
1626 	case NETDEV_DOWN:
1627 		err = mpls_ifdown(dev, event);
1628 		if (err)
1629 			return notifier_from_errno(err);
1630 		break;
1631 	case NETDEV_UP:
1632 		flags = dev_get_flags(dev);
1633 		if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1634 			mpls_ifup(dev, RTNH_F_DEAD | RTNH_F_LINKDOWN);
1635 		else
1636 			mpls_ifup(dev, RTNH_F_DEAD);
1637 		break;
1638 	case NETDEV_CHANGE:
1639 		flags = dev_get_flags(dev);
1640 		if (flags & (IFF_RUNNING | IFF_LOWER_UP)) {
1641 			mpls_ifup(dev, RTNH_F_DEAD | RTNH_F_LINKDOWN);
1642 		} else {
1643 			err = mpls_ifdown(dev, event);
1644 			if (err)
1645 				return notifier_from_errno(err);
1646 		}
1647 		break;
1648 	case NETDEV_UNREGISTER:
1649 		err = mpls_ifdown(dev, event);
1650 		if (err)
1651 			return notifier_from_errno(err);
1652 		mdev = mpls_dev_get(dev);
1653 		if (mdev) {
1654 			mpls_dev_sysctl_unregister(dev, mdev);
1655 			RCU_INIT_POINTER(dev->mpls_ptr, NULL);
1656 			call_rcu(&mdev->rcu, mpls_dev_destroy_rcu);
1657 		}
1658 		break;
1659 	case NETDEV_CHANGENAME:
1660 		mdev = mpls_dev_get(dev);
1661 		if (mdev) {
1662 			mpls_dev_sysctl_unregister(dev, mdev);
1663 			err = mpls_dev_sysctl_register(dev, mdev);
1664 			if (err)
1665 				return notifier_from_errno(err);
1666 		}
1667 		break;
1668 	}
1669 	return NOTIFY_OK;
1670 }
1671 
1672 static struct notifier_block mpls_dev_notifier = {
1673 	.notifier_call = mpls_dev_notify,
1674 };
1675 
1676 static int nla_put_via(struct sk_buff *skb,
1677 		       u8 table, const void *addr, int alen)
1678 {
1679 	static const int table_to_family[NEIGH_NR_TABLES + 1] = {
1680 		AF_INET, AF_INET6, AF_DECnet, AF_PACKET,
1681 	};
1682 	struct nlattr *nla;
1683 	struct rtvia *via;
1684 	int family = AF_UNSPEC;
1685 
1686 	nla = nla_reserve(skb, RTA_VIA, alen + 2);
1687 	if (!nla)
1688 		return -EMSGSIZE;
1689 
1690 	if (table <= NEIGH_NR_TABLES)
1691 		family = table_to_family[table];
1692 
1693 	via = nla_data(nla);
1694 	via->rtvia_family = family;
1695 	memcpy(via->rtvia_addr, addr, alen);
1696 	return 0;
1697 }
1698 
1699 int nla_put_labels(struct sk_buff *skb, int attrtype,
1700 		   u8 labels, const u32 label[])
1701 {
1702 	struct nlattr *nla;
1703 	struct mpls_shim_hdr *nla_label;
1704 	bool bos;
1705 	int i;
1706 	nla = nla_reserve(skb, attrtype, labels*4);
1707 	if (!nla)
1708 		return -EMSGSIZE;
1709 
1710 	nla_label = nla_data(nla);
1711 	bos = true;
1712 	for (i = labels - 1; i >= 0; i--) {
1713 		nla_label[i] = mpls_entry_encode(label[i], 0, 0, bos);
1714 		bos = false;
1715 	}
1716 
1717 	return 0;
1718 }
1719 EXPORT_SYMBOL_GPL(nla_put_labels);
1720 
1721 int nla_get_labels(const struct nlattr *nla, u8 max_labels, u8 *labels,
1722 		   u32 label[], struct netlink_ext_ack *extack)
1723 {
1724 	unsigned len = nla_len(nla);
1725 	struct mpls_shim_hdr *nla_label;
1726 	u8 nla_labels;
1727 	bool bos;
1728 	int i;
1729 
1730 	/* len needs to be an even multiple of 4 (the label size). Number
1731 	 * of labels is a u8 so check for overflow.
1732 	 */
1733 	if (len & 3 || len / 4 > 255) {
1734 		NL_SET_ERR_MSG_ATTR(extack, nla,
1735 				    "Invalid length for labels attribute");
1736 		return -EINVAL;
1737 	}
1738 
1739 	/* Limit the number of new labels allowed */
1740 	nla_labels = len/4;
1741 	if (nla_labels > max_labels) {
1742 		NL_SET_ERR_MSG(extack, "Too many labels");
1743 		return -EINVAL;
1744 	}
1745 
1746 	/* when label == NULL, caller wants number of labels */
1747 	if (!label)
1748 		goto out;
1749 
1750 	nla_label = nla_data(nla);
1751 	bos = true;
1752 	for (i = nla_labels - 1; i >= 0; i--, bos = false) {
1753 		struct mpls_entry_decoded dec;
1754 		dec = mpls_entry_decode(nla_label + i);
1755 
1756 		/* Ensure the bottom of stack flag is properly set
1757 		 * and ttl and tc are both clear.
1758 		 */
1759 		if (dec.ttl) {
1760 			NL_SET_ERR_MSG_ATTR(extack, nla,
1761 					    "TTL in label must be 0");
1762 			return -EINVAL;
1763 		}
1764 
1765 		if (dec.tc) {
1766 			NL_SET_ERR_MSG_ATTR(extack, nla,
1767 					    "Traffic class in label must be 0");
1768 			return -EINVAL;
1769 		}
1770 
1771 		if (dec.bos != bos) {
1772 			NL_SET_BAD_ATTR(extack, nla);
1773 			if (bos) {
1774 				NL_SET_ERR_MSG(extack,
1775 					       "BOS bit must be set in first label");
1776 			} else {
1777 				NL_SET_ERR_MSG(extack,
1778 					       "BOS bit can only be set in first label");
1779 			}
1780 			return -EINVAL;
1781 		}
1782 
1783 		switch (dec.label) {
1784 		case MPLS_LABEL_IMPLNULL:
1785 			/* RFC3032: This is a label that an LSR may
1786 			 * assign and distribute, but which never
1787 			 * actually appears in the encapsulation.
1788 			 */
1789 			NL_SET_ERR_MSG_ATTR(extack, nla,
1790 					    "Implicit NULL Label (3) can not be used in encapsulation");
1791 			return -EINVAL;
1792 		}
1793 
1794 		label[i] = dec.label;
1795 	}
1796 out:
1797 	*labels = nla_labels;
1798 	return 0;
1799 }
1800 EXPORT_SYMBOL_GPL(nla_get_labels);
1801 
1802 static int rtm_to_route_config(struct sk_buff *skb,
1803 			       struct nlmsghdr *nlh,
1804 			       struct mpls_route_config *cfg,
1805 			       struct netlink_ext_ack *extack)
1806 {
1807 	struct rtmsg *rtm;
1808 	struct nlattr *tb[RTA_MAX+1];
1809 	int index;
1810 	int err;
1811 
1812 	err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
1813 				     rtm_mpls_policy, extack);
1814 	if (err < 0)
1815 		goto errout;
1816 
1817 	err = -EINVAL;
1818 	rtm = nlmsg_data(nlh);
1819 
1820 	if (rtm->rtm_family != AF_MPLS) {
1821 		NL_SET_ERR_MSG(extack, "Invalid address family in rtmsg");
1822 		goto errout;
1823 	}
1824 	if (rtm->rtm_dst_len != 20) {
1825 		NL_SET_ERR_MSG(extack, "rtm_dst_len must be 20 for MPLS");
1826 		goto errout;
1827 	}
1828 	if (rtm->rtm_src_len != 0) {
1829 		NL_SET_ERR_MSG(extack, "rtm_src_len must be 0 for MPLS");
1830 		goto errout;
1831 	}
1832 	if (rtm->rtm_tos != 0) {
1833 		NL_SET_ERR_MSG(extack, "rtm_tos must be 0 for MPLS");
1834 		goto errout;
1835 	}
1836 	if (rtm->rtm_table != RT_TABLE_MAIN) {
1837 		NL_SET_ERR_MSG(extack,
1838 			       "MPLS only supports the main route table");
1839 		goto errout;
1840 	}
1841 	/* Any value is acceptable for rtm_protocol */
1842 
1843 	/* As mpls uses destination specific addresses
1844 	 * (or source specific address in the case of multicast)
1845 	 * all addresses have universal scope.
1846 	 */
1847 	if (rtm->rtm_scope != RT_SCOPE_UNIVERSE) {
1848 		NL_SET_ERR_MSG(extack,
1849 			       "Invalid route scope  - MPLS only supports UNIVERSE");
1850 		goto errout;
1851 	}
1852 	if (rtm->rtm_type != RTN_UNICAST) {
1853 		NL_SET_ERR_MSG(extack,
1854 			       "Invalid route type - MPLS only supports UNICAST");
1855 		goto errout;
1856 	}
1857 	if (rtm->rtm_flags != 0) {
1858 		NL_SET_ERR_MSG(extack, "rtm_flags must be 0 for MPLS");
1859 		goto errout;
1860 	}
1861 
1862 	cfg->rc_label		= LABEL_NOT_SPECIFIED;
1863 	cfg->rc_protocol	= rtm->rtm_protocol;
1864 	cfg->rc_via_table	= MPLS_NEIGH_TABLE_UNSPEC;
1865 	cfg->rc_ttl_propagate	= MPLS_TTL_PROP_DEFAULT;
1866 	cfg->rc_nlflags		= nlh->nlmsg_flags;
1867 	cfg->rc_nlinfo.portid	= NETLINK_CB(skb).portid;
1868 	cfg->rc_nlinfo.nlh	= nlh;
1869 	cfg->rc_nlinfo.nl_net	= sock_net(skb->sk);
1870 
1871 	for (index = 0; index <= RTA_MAX; index++) {
1872 		struct nlattr *nla = tb[index];
1873 		if (!nla)
1874 			continue;
1875 
1876 		switch (index) {
1877 		case RTA_OIF:
1878 			cfg->rc_ifindex = nla_get_u32(nla);
1879 			break;
1880 		case RTA_NEWDST:
1881 			if (nla_get_labels(nla, MAX_NEW_LABELS,
1882 					   &cfg->rc_output_labels,
1883 					   cfg->rc_output_label, extack))
1884 				goto errout;
1885 			break;
1886 		case RTA_DST:
1887 		{
1888 			u8 label_count;
1889 			if (nla_get_labels(nla, 1, &label_count,
1890 					   &cfg->rc_label, extack))
1891 				goto errout;
1892 
1893 			if (!mpls_label_ok(cfg->rc_nlinfo.nl_net,
1894 					   &cfg->rc_label, extack))
1895 				goto errout;
1896 			break;
1897 		}
1898 		case RTA_GATEWAY:
1899 			NL_SET_ERR_MSG(extack, "MPLS does not support RTA_GATEWAY attribute");
1900 			goto errout;
1901 		case RTA_VIA:
1902 		{
1903 			if (nla_get_via(nla, &cfg->rc_via_alen,
1904 					&cfg->rc_via_table, cfg->rc_via,
1905 					extack))
1906 				goto errout;
1907 			break;
1908 		}
1909 		case RTA_MULTIPATH:
1910 		{
1911 			cfg->rc_mp = nla_data(nla);
1912 			cfg->rc_mp_len = nla_len(nla);
1913 			break;
1914 		}
1915 		case RTA_TTL_PROPAGATE:
1916 		{
1917 			u8 ttl_propagate = nla_get_u8(nla);
1918 
1919 			if (ttl_propagate > 1) {
1920 				NL_SET_ERR_MSG_ATTR(extack, nla,
1921 						    "RTA_TTL_PROPAGATE can only be 0 or 1");
1922 				goto errout;
1923 			}
1924 			cfg->rc_ttl_propagate = ttl_propagate ?
1925 				MPLS_TTL_PROP_ENABLED :
1926 				MPLS_TTL_PROP_DISABLED;
1927 			break;
1928 		}
1929 		default:
1930 			NL_SET_ERR_MSG_ATTR(extack, nla, "Unknown attribute");
1931 			/* Unsupported attribute */
1932 			goto errout;
1933 		}
1934 	}
1935 
1936 	err = 0;
1937 errout:
1938 	return err;
1939 }
1940 
1941 static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1942 			     struct netlink_ext_ack *extack)
1943 {
1944 	struct mpls_route_config *cfg;
1945 	int err;
1946 
1947 	cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
1948 	if (!cfg)
1949 		return -ENOMEM;
1950 
1951 	err = rtm_to_route_config(skb, nlh, cfg, extack);
1952 	if (err < 0)
1953 		goto out;
1954 
1955 	err = mpls_route_del(cfg, extack);
1956 out:
1957 	kfree(cfg);
1958 
1959 	return err;
1960 }
1961 
1962 
1963 static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
1964 			     struct netlink_ext_ack *extack)
1965 {
1966 	struct mpls_route_config *cfg;
1967 	int err;
1968 
1969 	cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
1970 	if (!cfg)
1971 		return -ENOMEM;
1972 
1973 	err = rtm_to_route_config(skb, nlh, cfg, extack);
1974 	if (err < 0)
1975 		goto out;
1976 
1977 	err = mpls_route_add(cfg, extack);
1978 out:
1979 	kfree(cfg);
1980 
1981 	return err;
1982 }
1983 
1984 static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
1985 			   u32 label, struct mpls_route *rt, int flags)
1986 {
1987 	struct net_device *dev;
1988 	struct nlmsghdr *nlh;
1989 	struct rtmsg *rtm;
1990 
1991 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1992 	if (nlh == NULL)
1993 		return -EMSGSIZE;
1994 
1995 	rtm = nlmsg_data(nlh);
1996 	rtm->rtm_family = AF_MPLS;
1997 	rtm->rtm_dst_len = 20;
1998 	rtm->rtm_src_len = 0;
1999 	rtm->rtm_tos = 0;
2000 	rtm->rtm_table = RT_TABLE_MAIN;
2001 	rtm->rtm_protocol = rt->rt_protocol;
2002 	rtm->rtm_scope = RT_SCOPE_UNIVERSE;
2003 	rtm->rtm_type = RTN_UNICAST;
2004 	rtm->rtm_flags = 0;
2005 
2006 	if (nla_put_labels(skb, RTA_DST, 1, &label))
2007 		goto nla_put_failure;
2008 
2009 	if (rt->rt_ttl_propagate != MPLS_TTL_PROP_DEFAULT) {
2010 		bool ttl_propagate =
2011 			rt->rt_ttl_propagate == MPLS_TTL_PROP_ENABLED;
2012 
2013 		if (nla_put_u8(skb, RTA_TTL_PROPAGATE,
2014 			       ttl_propagate))
2015 			goto nla_put_failure;
2016 	}
2017 	if (rt->rt_nhn == 1) {
2018 		const struct mpls_nh *nh = rt->rt_nh;
2019 
2020 		if (nh->nh_labels &&
2021 		    nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
2022 				   nh->nh_label))
2023 			goto nla_put_failure;
2024 		if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC &&
2025 		    nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh),
2026 				nh->nh_via_alen))
2027 			goto nla_put_failure;
2028 		dev = nh->nh_dev;
2029 		if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
2030 			goto nla_put_failure;
2031 		if (nh->nh_flags & RTNH_F_LINKDOWN)
2032 			rtm->rtm_flags |= RTNH_F_LINKDOWN;
2033 		if (nh->nh_flags & RTNH_F_DEAD)
2034 			rtm->rtm_flags |= RTNH_F_DEAD;
2035 	} else {
2036 		struct rtnexthop *rtnh;
2037 		struct nlattr *mp;
2038 		u8 linkdown = 0;
2039 		u8 dead = 0;
2040 
2041 		mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
2042 		if (!mp)
2043 			goto nla_put_failure;
2044 
2045 		for_nexthops(rt) {
2046 			dev = nh->nh_dev;
2047 			if (!dev)
2048 				continue;
2049 
2050 			rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
2051 			if (!rtnh)
2052 				goto nla_put_failure;
2053 
2054 			rtnh->rtnh_ifindex = dev->ifindex;
2055 			if (nh->nh_flags & RTNH_F_LINKDOWN) {
2056 				rtnh->rtnh_flags |= RTNH_F_LINKDOWN;
2057 				linkdown++;
2058 			}
2059 			if (nh->nh_flags & RTNH_F_DEAD) {
2060 				rtnh->rtnh_flags |= RTNH_F_DEAD;
2061 				dead++;
2062 			}
2063 
2064 			if (nh->nh_labels && nla_put_labels(skb, RTA_NEWDST,
2065 							    nh->nh_labels,
2066 							    nh->nh_label))
2067 				goto nla_put_failure;
2068 			if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC &&
2069 			    nla_put_via(skb, nh->nh_via_table,
2070 					mpls_nh_via(rt, nh),
2071 					nh->nh_via_alen))
2072 				goto nla_put_failure;
2073 
2074 			/* length of rtnetlink header + attributes */
2075 			rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
2076 		} endfor_nexthops(rt);
2077 
2078 		if (linkdown == rt->rt_nhn)
2079 			rtm->rtm_flags |= RTNH_F_LINKDOWN;
2080 		if (dead == rt->rt_nhn)
2081 			rtm->rtm_flags |= RTNH_F_DEAD;
2082 
2083 		nla_nest_end(skb, mp);
2084 	}
2085 
2086 	nlmsg_end(skb, nlh);
2087 	return 0;
2088 
2089 nla_put_failure:
2090 	nlmsg_cancel(skb, nlh);
2091 	return -EMSGSIZE;
2092 }
2093 
2094 #if IS_ENABLED(CONFIG_INET)
2095 static int mpls_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
2096 				   struct fib_dump_filter *filter,
2097 				   struct netlink_callback *cb)
2098 {
2099 	return ip_valid_fib_dump_req(net, nlh, filter, cb);
2100 }
2101 #else
2102 static int mpls_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
2103 				   struct fib_dump_filter *filter,
2104 				   struct netlink_callback *cb)
2105 {
2106 	struct netlink_ext_ack *extack = cb->extack;
2107 	struct nlattr *tb[RTA_MAX + 1];
2108 	struct rtmsg *rtm;
2109 	int err, i;
2110 
2111 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
2112 		NL_SET_ERR_MSG_MOD(extack, "Invalid header for FIB dump request");
2113 		return -EINVAL;
2114 	}
2115 
2116 	rtm = nlmsg_data(nlh);
2117 	if (rtm->rtm_dst_len || rtm->rtm_src_len  || rtm->rtm_tos   ||
2118 	    rtm->rtm_table   || rtm->rtm_scope    || rtm->rtm_type  ||
2119 	    rtm->rtm_flags) {
2120 		NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for FIB dump request");
2121 		return -EINVAL;
2122 	}
2123 
2124 	if (rtm->rtm_protocol) {
2125 		filter->protocol = rtm->rtm_protocol;
2126 		filter->filter_set = 1;
2127 		cb->answer_flags = NLM_F_DUMP_FILTERED;
2128 	}
2129 
2130 	err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
2131 					    rtm_mpls_policy, extack);
2132 	if (err < 0)
2133 		return err;
2134 
2135 	for (i = 0; i <= RTA_MAX; ++i) {
2136 		int ifindex;
2137 
2138 		if (i == RTA_OIF) {
2139 			ifindex = nla_get_u32(tb[i]);
2140 			filter->dev = __dev_get_by_index(net, ifindex);
2141 			if (!filter->dev)
2142 				return -ENODEV;
2143 			filter->filter_set = 1;
2144 		} else if (tb[i]) {
2145 			NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in dump request");
2146 			return -EINVAL;
2147 		}
2148 	}
2149 
2150 	return 0;
2151 }
2152 #endif
2153 
2154 static bool mpls_rt_uses_dev(struct mpls_route *rt,
2155 			     const struct net_device *dev)
2156 {
2157 	if (rt->rt_nhn == 1) {
2158 		struct mpls_nh *nh = rt->rt_nh;
2159 
2160 		if (nh->nh_dev == dev)
2161 			return true;
2162 	} else {
2163 		for_nexthops(rt) {
2164 			if (nh->nh_dev == dev)
2165 				return true;
2166 		} endfor_nexthops(rt);
2167 	}
2168 
2169 	return false;
2170 }
2171 
2172 static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
2173 {
2174 	const struct nlmsghdr *nlh = cb->nlh;
2175 	struct net *net = sock_net(skb->sk);
2176 	struct mpls_route __rcu **platform_label;
2177 	struct fib_dump_filter filter = {};
2178 	unsigned int flags = NLM_F_MULTI;
2179 	size_t platform_labels;
2180 	unsigned int index;
2181 
2182 	ASSERT_RTNL();
2183 
2184 	if (cb->strict_check) {
2185 		int err;
2186 
2187 		err = mpls_valid_fib_dump_req(net, nlh, &filter, cb);
2188 		if (err < 0)
2189 			return err;
2190 
2191 		/* for MPLS, there is only 1 table with fixed type and flags.
2192 		 * If either are set in the filter then return nothing.
2193 		 */
2194 		if ((filter.table_id && filter.table_id != RT_TABLE_MAIN) ||
2195 		    (filter.rt_type && filter.rt_type != RTN_UNICAST) ||
2196 		     filter.flags)
2197 			return skb->len;
2198 	}
2199 
2200 	index = cb->args[0];
2201 	if (index < MPLS_LABEL_FIRST_UNRESERVED)
2202 		index = MPLS_LABEL_FIRST_UNRESERVED;
2203 
2204 	platform_label = rtnl_dereference(net->mpls.platform_label);
2205 	platform_labels = net->mpls.platform_labels;
2206 
2207 	if (filter.filter_set)
2208 		flags |= NLM_F_DUMP_FILTERED;
2209 
2210 	for (; index < platform_labels; index++) {
2211 		struct mpls_route *rt;
2212 
2213 		rt = rtnl_dereference(platform_label[index]);
2214 		if (!rt)
2215 			continue;
2216 
2217 		if ((filter.dev && !mpls_rt_uses_dev(rt, filter.dev)) ||
2218 		    (filter.protocol && rt->rt_protocol != filter.protocol))
2219 			continue;
2220 
2221 		if (mpls_dump_route(skb, NETLINK_CB(cb->skb).portid,
2222 				    cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2223 				    index, rt, flags) < 0)
2224 			break;
2225 	}
2226 	cb->args[0] = index;
2227 
2228 	return skb->len;
2229 }
2230 
2231 static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
2232 {
2233 	size_t payload =
2234 		NLMSG_ALIGN(sizeof(struct rtmsg))
2235 		+ nla_total_size(4)			/* RTA_DST */
2236 		+ nla_total_size(1);			/* RTA_TTL_PROPAGATE */
2237 
2238 	if (rt->rt_nhn == 1) {
2239 		struct mpls_nh *nh = rt->rt_nh;
2240 
2241 		if (nh->nh_dev)
2242 			payload += nla_total_size(4); /* RTA_OIF */
2243 		if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC) /* RTA_VIA */
2244 			payload += nla_total_size(2 + nh->nh_via_alen);
2245 		if (nh->nh_labels) /* RTA_NEWDST */
2246 			payload += nla_total_size(nh->nh_labels * 4);
2247 	} else {
2248 		/* each nexthop is packed in an attribute */
2249 		size_t nhsize = 0;
2250 
2251 		for_nexthops(rt) {
2252 			if (!nh->nh_dev)
2253 				continue;
2254 			nhsize += nla_total_size(sizeof(struct rtnexthop));
2255 			/* RTA_VIA */
2256 			if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC)
2257 				nhsize += nla_total_size(2 + nh->nh_via_alen);
2258 			if (nh->nh_labels)
2259 				nhsize += nla_total_size(nh->nh_labels * 4);
2260 		} endfor_nexthops(rt);
2261 		/* nested attribute */
2262 		payload += nla_total_size(nhsize);
2263 	}
2264 
2265 	return payload;
2266 }
2267 
2268 static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
2269 		       struct nlmsghdr *nlh, struct net *net, u32 portid,
2270 		       unsigned int nlm_flags)
2271 {
2272 	struct sk_buff *skb;
2273 	u32 seq = nlh ? nlh->nlmsg_seq : 0;
2274 	int err = -ENOBUFS;
2275 
2276 	skb = nlmsg_new(lfib_nlmsg_size(rt), GFP_KERNEL);
2277 	if (skb == NULL)
2278 		goto errout;
2279 
2280 	err = mpls_dump_route(skb, portid, seq, event, label, rt, nlm_flags);
2281 	if (err < 0) {
2282 		/* -EMSGSIZE implies BUG in lfib_nlmsg_size */
2283 		WARN_ON(err == -EMSGSIZE);
2284 		kfree_skb(skb);
2285 		goto errout;
2286 	}
2287 	rtnl_notify(skb, net, portid, RTNLGRP_MPLS_ROUTE, nlh, GFP_KERNEL);
2288 
2289 	return;
2290 errout:
2291 	if (err < 0)
2292 		rtnl_set_sk_err(net, RTNLGRP_MPLS_ROUTE, err);
2293 }
2294 
2295 static int mpls_valid_getroute_req(struct sk_buff *skb,
2296 				   const struct nlmsghdr *nlh,
2297 				   struct nlattr **tb,
2298 				   struct netlink_ext_ack *extack)
2299 {
2300 	struct rtmsg *rtm;
2301 	int i, err;
2302 
2303 	if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*rtm))) {
2304 		NL_SET_ERR_MSG_MOD(extack,
2305 				   "Invalid header for get route request");
2306 		return -EINVAL;
2307 	}
2308 
2309 	if (!netlink_strict_get_check(skb))
2310 		return nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
2311 					      rtm_mpls_policy, extack);
2312 
2313 	rtm = nlmsg_data(nlh);
2314 	if ((rtm->rtm_dst_len && rtm->rtm_dst_len != 20) ||
2315 	    rtm->rtm_src_len || rtm->rtm_tos || rtm->rtm_table ||
2316 	    rtm->rtm_protocol || rtm->rtm_scope || rtm->rtm_type) {
2317 		NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for get route request");
2318 		return -EINVAL;
2319 	}
2320 	if (rtm->rtm_flags & ~RTM_F_FIB_MATCH) {
2321 		NL_SET_ERR_MSG_MOD(extack,
2322 				   "Invalid flags for get route request");
2323 		return -EINVAL;
2324 	}
2325 
2326 	err = nlmsg_parse_deprecated_strict(nlh, sizeof(*rtm), tb, RTA_MAX,
2327 					    rtm_mpls_policy, extack);
2328 	if (err)
2329 		return err;
2330 
2331 	if ((tb[RTA_DST] || tb[RTA_NEWDST]) && !rtm->rtm_dst_len) {
2332 		NL_SET_ERR_MSG_MOD(extack, "rtm_dst_len must be 20 for MPLS");
2333 		return -EINVAL;
2334 	}
2335 
2336 	for (i = 0; i <= RTA_MAX; i++) {
2337 		if (!tb[i])
2338 			continue;
2339 
2340 		switch (i) {
2341 		case RTA_DST:
2342 		case RTA_NEWDST:
2343 			break;
2344 		default:
2345 			NL_SET_ERR_MSG_MOD(extack, "Unsupported attribute in get route request");
2346 			return -EINVAL;
2347 		}
2348 	}
2349 
2350 	return 0;
2351 }
2352 
2353 static int mpls_getroute(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
2354 			 struct netlink_ext_ack *extack)
2355 {
2356 	struct net *net = sock_net(in_skb->sk);
2357 	u32 portid = NETLINK_CB(in_skb).portid;
2358 	u32 in_label = LABEL_NOT_SPECIFIED;
2359 	struct nlattr *tb[RTA_MAX + 1];
2360 	u32 labels[MAX_NEW_LABELS];
2361 	struct mpls_shim_hdr *hdr;
2362 	unsigned int hdr_size = 0;
2363 	const struct mpls_nh *nh;
2364 	struct net_device *dev;
2365 	struct mpls_route *rt;
2366 	struct rtmsg *rtm, *r;
2367 	struct nlmsghdr *nlh;
2368 	struct sk_buff *skb;
2369 	u8 n_labels;
2370 	int err;
2371 
2372 	err = mpls_valid_getroute_req(in_skb, in_nlh, tb, extack);
2373 	if (err < 0)
2374 		goto errout;
2375 
2376 	rtm = nlmsg_data(in_nlh);
2377 
2378 	if (tb[RTA_DST]) {
2379 		u8 label_count;
2380 
2381 		if (nla_get_labels(tb[RTA_DST], 1, &label_count,
2382 				   &in_label, extack)) {
2383 			err = -EINVAL;
2384 			goto errout;
2385 		}
2386 
2387 		if (!mpls_label_ok(net, &in_label, extack)) {
2388 			err = -EINVAL;
2389 			goto errout;
2390 		}
2391 	}
2392 
2393 	rt = mpls_route_input_rcu(net, in_label);
2394 	if (!rt) {
2395 		err = -ENETUNREACH;
2396 		goto errout;
2397 	}
2398 
2399 	if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
2400 		skb = nlmsg_new(lfib_nlmsg_size(rt), GFP_KERNEL);
2401 		if (!skb) {
2402 			err = -ENOBUFS;
2403 			goto errout;
2404 		}
2405 
2406 		err = mpls_dump_route(skb, portid, in_nlh->nlmsg_seq,
2407 				      RTM_NEWROUTE, in_label, rt, 0);
2408 		if (err < 0) {
2409 			/* -EMSGSIZE implies BUG in lfib_nlmsg_size */
2410 			WARN_ON(err == -EMSGSIZE);
2411 			goto errout_free;
2412 		}
2413 
2414 		return rtnl_unicast(skb, net, portid);
2415 	}
2416 
2417 	if (tb[RTA_NEWDST]) {
2418 		if (nla_get_labels(tb[RTA_NEWDST], MAX_NEW_LABELS, &n_labels,
2419 				   labels, extack) != 0) {
2420 			err = -EINVAL;
2421 			goto errout;
2422 		}
2423 
2424 		hdr_size = n_labels * sizeof(struct mpls_shim_hdr);
2425 	}
2426 
2427 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
2428 	if (!skb) {
2429 		err = -ENOBUFS;
2430 		goto errout;
2431 	}
2432 
2433 	skb->protocol = htons(ETH_P_MPLS_UC);
2434 
2435 	if (hdr_size) {
2436 		bool bos;
2437 		int i;
2438 
2439 		if (skb_cow(skb, hdr_size)) {
2440 			err = -ENOBUFS;
2441 			goto errout_free;
2442 		}
2443 
2444 		skb_reserve(skb, hdr_size);
2445 		skb_push(skb, hdr_size);
2446 		skb_reset_network_header(skb);
2447 
2448 		/* Push new labels */
2449 		hdr = mpls_hdr(skb);
2450 		bos = true;
2451 		for (i = n_labels - 1; i >= 0; i--) {
2452 			hdr[i] = mpls_entry_encode(labels[i],
2453 						   1, 0, bos);
2454 			bos = false;
2455 		}
2456 	}
2457 
2458 	nh = mpls_select_multipath(rt, skb);
2459 	if (!nh) {
2460 		err = -ENETUNREACH;
2461 		goto errout_free;
2462 	}
2463 
2464 	if (hdr_size) {
2465 		skb_pull(skb, hdr_size);
2466 		skb_reset_network_header(skb);
2467 	}
2468 
2469 	nlh = nlmsg_put(skb, portid, in_nlh->nlmsg_seq,
2470 			RTM_NEWROUTE, sizeof(*r), 0);
2471 	if (!nlh) {
2472 		err = -EMSGSIZE;
2473 		goto errout_free;
2474 	}
2475 
2476 	r = nlmsg_data(nlh);
2477 	r->rtm_family	 = AF_MPLS;
2478 	r->rtm_dst_len	= 20;
2479 	r->rtm_src_len	= 0;
2480 	r->rtm_table	= RT_TABLE_MAIN;
2481 	r->rtm_type	= RTN_UNICAST;
2482 	r->rtm_scope	= RT_SCOPE_UNIVERSE;
2483 	r->rtm_protocol = rt->rt_protocol;
2484 	r->rtm_flags	= 0;
2485 
2486 	if (nla_put_labels(skb, RTA_DST, 1, &in_label))
2487 		goto nla_put_failure;
2488 
2489 	if (nh->nh_labels &&
2490 	    nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
2491 			   nh->nh_label))
2492 		goto nla_put_failure;
2493 
2494 	if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC &&
2495 	    nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh),
2496 			nh->nh_via_alen))
2497 		goto nla_put_failure;
2498 	dev = nh->nh_dev;
2499 	if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
2500 		goto nla_put_failure;
2501 
2502 	nlmsg_end(skb, nlh);
2503 
2504 	err = rtnl_unicast(skb, net, portid);
2505 errout:
2506 	return err;
2507 
2508 nla_put_failure:
2509 	nlmsg_cancel(skb, nlh);
2510 	err = -EMSGSIZE;
2511 errout_free:
2512 	kfree_skb(skb);
2513 	return err;
2514 }
2515 
2516 static int resize_platform_label_table(struct net *net, size_t limit)
2517 {
2518 	size_t size = sizeof(struct mpls_route *) * limit;
2519 	size_t old_limit;
2520 	size_t cp_size;
2521 	struct mpls_route __rcu **labels = NULL, **old;
2522 	struct mpls_route *rt0 = NULL, *rt2 = NULL;
2523 	unsigned index;
2524 
2525 	if (size) {
2526 		labels = kvzalloc(size, GFP_KERNEL);
2527 		if (!labels)
2528 			goto nolabels;
2529 	}
2530 
2531 	/* In case the predefined labels need to be populated */
2532 	if (limit > MPLS_LABEL_IPV4NULL) {
2533 		struct net_device *lo = net->loopback_dev;
2534 		rt0 = mpls_rt_alloc(1, lo->addr_len, 0);
2535 		if (IS_ERR(rt0))
2536 			goto nort0;
2537 		rt0->rt_nh->nh_dev = lo;
2538 		rt0->rt_protocol = RTPROT_KERNEL;
2539 		rt0->rt_payload_type = MPT_IPV4;
2540 		rt0->rt_ttl_propagate = MPLS_TTL_PROP_DEFAULT;
2541 		rt0->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
2542 		rt0->rt_nh->nh_via_alen = lo->addr_len;
2543 		memcpy(__mpls_nh_via(rt0, rt0->rt_nh), lo->dev_addr,
2544 		       lo->addr_len);
2545 	}
2546 	if (limit > MPLS_LABEL_IPV6NULL) {
2547 		struct net_device *lo = net->loopback_dev;
2548 		rt2 = mpls_rt_alloc(1, lo->addr_len, 0);
2549 		if (IS_ERR(rt2))
2550 			goto nort2;
2551 		rt2->rt_nh->nh_dev = lo;
2552 		rt2->rt_protocol = RTPROT_KERNEL;
2553 		rt2->rt_payload_type = MPT_IPV6;
2554 		rt2->rt_ttl_propagate = MPLS_TTL_PROP_DEFAULT;
2555 		rt2->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
2556 		rt2->rt_nh->nh_via_alen = lo->addr_len;
2557 		memcpy(__mpls_nh_via(rt2, rt2->rt_nh), lo->dev_addr,
2558 		       lo->addr_len);
2559 	}
2560 
2561 	rtnl_lock();
2562 	/* Remember the original table */
2563 	old = rtnl_dereference(net->mpls.platform_label);
2564 	old_limit = net->mpls.platform_labels;
2565 
2566 	/* Free any labels beyond the new table */
2567 	for (index = limit; index < old_limit; index++)
2568 		mpls_route_update(net, index, NULL, NULL);
2569 
2570 	/* Copy over the old labels */
2571 	cp_size = size;
2572 	if (old_limit < limit)
2573 		cp_size = old_limit * sizeof(struct mpls_route *);
2574 
2575 	memcpy(labels, old, cp_size);
2576 
2577 	/* If needed set the predefined labels */
2578 	if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
2579 	    (limit > MPLS_LABEL_IPV6NULL)) {
2580 		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
2581 		rt2 = NULL;
2582 	}
2583 
2584 	if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
2585 	    (limit > MPLS_LABEL_IPV4NULL)) {
2586 		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
2587 		rt0 = NULL;
2588 	}
2589 
2590 	/* Update the global pointers */
2591 	net->mpls.platform_labels = limit;
2592 	rcu_assign_pointer(net->mpls.platform_label, labels);
2593 
2594 	rtnl_unlock();
2595 
2596 	mpls_rt_free(rt2);
2597 	mpls_rt_free(rt0);
2598 
2599 	if (old) {
2600 		synchronize_rcu();
2601 		kvfree(old);
2602 	}
2603 	return 0;
2604 
2605 nort2:
2606 	mpls_rt_free(rt0);
2607 nort0:
2608 	kvfree(labels);
2609 nolabels:
2610 	return -ENOMEM;
2611 }
2612 
2613 static int mpls_platform_labels(struct ctl_table *table, int write,
2614 				void *buffer, size_t *lenp, loff_t *ppos)
2615 {
2616 	struct net *net = table->data;
2617 	int platform_labels = net->mpls.platform_labels;
2618 	int ret;
2619 	struct ctl_table tmp = {
2620 		.procname	= table->procname,
2621 		.data		= &platform_labels,
2622 		.maxlen		= sizeof(int),
2623 		.mode		= table->mode,
2624 		.extra1		= SYSCTL_ZERO,
2625 		.extra2		= &label_limit,
2626 	};
2627 
2628 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
2629 
2630 	if (write && ret == 0)
2631 		ret = resize_platform_label_table(net, platform_labels);
2632 
2633 	return ret;
2634 }
2635 
2636 #define MPLS_NS_SYSCTL_OFFSET(field)		\
2637 	(&((struct net *)0)->field)
2638 
2639 static const struct ctl_table mpls_table[] = {
2640 	{
2641 		.procname	= "platform_labels",
2642 		.data		= NULL,
2643 		.maxlen		= sizeof(int),
2644 		.mode		= 0644,
2645 		.proc_handler	= mpls_platform_labels,
2646 	},
2647 	{
2648 		.procname	= "ip_ttl_propagate",
2649 		.data		= MPLS_NS_SYSCTL_OFFSET(mpls.ip_ttl_propagate),
2650 		.maxlen		= sizeof(int),
2651 		.mode		= 0644,
2652 		.proc_handler	= proc_dointvec_minmax,
2653 		.extra1		= SYSCTL_ZERO,
2654 		.extra2		= SYSCTL_ONE,
2655 	},
2656 	{
2657 		.procname	= "default_ttl",
2658 		.data		= MPLS_NS_SYSCTL_OFFSET(mpls.default_ttl),
2659 		.maxlen		= sizeof(int),
2660 		.mode		= 0644,
2661 		.proc_handler	= proc_dointvec_minmax,
2662 		.extra1		= SYSCTL_ONE,
2663 		.extra2		= &ttl_max,
2664 	},
2665 	{ }
2666 };
2667 
2668 static int mpls_net_init(struct net *net)
2669 {
2670 	struct ctl_table *table;
2671 	int i;
2672 
2673 	net->mpls.platform_labels = 0;
2674 	net->mpls.platform_label = NULL;
2675 	net->mpls.ip_ttl_propagate = 1;
2676 	net->mpls.default_ttl = 255;
2677 
2678 	table = kmemdup(mpls_table, sizeof(mpls_table), GFP_KERNEL);
2679 	if (table == NULL)
2680 		return -ENOMEM;
2681 
2682 	/* Table data contains only offsets relative to the base of
2683 	 * the mdev at this point, so make them absolute.
2684 	 */
2685 	for (i = 0; i < ARRAY_SIZE(mpls_table) - 1; i++)
2686 		table[i].data = (char *)net + (uintptr_t)table[i].data;
2687 
2688 	net->mpls.ctl = register_net_sysctl(net, "net/mpls", table);
2689 	if (net->mpls.ctl == NULL) {
2690 		kfree(table);
2691 		return -ENOMEM;
2692 	}
2693 
2694 	return 0;
2695 }
2696 
2697 static void mpls_net_exit(struct net *net)
2698 {
2699 	struct mpls_route __rcu **platform_label;
2700 	size_t platform_labels;
2701 	struct ctl_table *table;
2702 	unsigned int index;
2703 
2704 	table = net->mpls.ctl->ctl_table_arg;
2705 	unregister_net_sysctl_table(net->mpls.ctl);
2706 	kfree(table);
2707 
2708 	/* An rcu grace period has passed since there was a device in
2709 	 * the network namespace (and thus the last in flight packet)
2710 	 * left this network namespace.  This is because
2711 	 * unregister_netdevice_many and netdev_run_todo has completed
2712 	 * for each network device that was in this network namespace.
2713 	 *
2714 	 * As such no additional rcu synchronization is necessary when
2715 	 * freeing the platform_label table.
2716 	 */
2717 	rtnl_lock();
2718 	platform_label = rtnl_dereference(net->mpls.platform_label);
2719 	platform_labels = net->mpls.platform_labels;
2720 	for (index = 0; index < platform_labels; index++) {
2721 		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
2722 		RCU_INIT_POINTER(platform_label[index], NULL);
2723 		mpls_notify_route(net, index, rt, NULL, NULL);
2724 		mpls_rt_free(rt);
2725 	}
2726 	rtnl_unlock();
2727 
2728 	kvfree(platform_label);
2729 }
2730 
2731 static struct pernet_operations mpls_net_ops = {
2732 	.init = mpls_net_init,
2733 	.exit = mpls_net_exit,
2734 };
2735 
2736 static struct rtnl_af_ops mpls_af_ops __read_mostly = {
2737 	.family		   = AF_MPLS,
2738 	.fill_stats_af	   = mpls_fill_stats_af,
2739 	.get_stats_af_size = mpls_get_stats_af_size,
2740 };
2741 
2742 static int __init mpls_init(void)
2743 {
2744 	int err;
2745 
2746 	BUILD_BUG_ON(sizeof(struct mpls_shim_hdr) != 4);
2747 
2748 	err = register_pernet_subsys(&mpls_net_ops);
2749 	if (err)
2750 		goto out;
2751 
2752 	err = register_netdevice_notifier(&mpls_dev_notifier);
2753 	if (err)
2754 		goto out_unregister_pernet;
2755 
2756 	dev_add_pack(&mpls_packet_type);
2757 
2758 	rtnl_af_register(&mpls_af_ops);
2759 
2760 	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_NEWROUTE,
2761 			     mpls_rtm_newroute, NULL, 0);
2762 	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_DELROUTE,
2763 			     mpls_rtm_delroute, NULL, 0);
2764 	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_GETROUTE,
2765 			     mpls_getroute, mpls_dump_routes, 0);
2766 	rtnl_register_module(THIS_MODULE, PF_MPLS, RTM_GETNETCONF,
2767 			     mpls_netconf_get_devconf,
2768 			     mpls_netconf_dump_devconf, 0);
2769 	err = ipgre_tunnel_encap_add_mpls_ops();
2770 	if (err)
2771 		pr_err("Can't add mpls over gre tunnel ops\n");
2772 
2773 	err = 0;
2774 out:
2775 	return err;
2776 
2777 out_unregister_pernet:
2778 	unregister_pernet_subsys(&mpls_net_ops);
2779 	goto out;
2780 }
2781 module_init(mpls_init);
2782 
2783 static void __exit mpls_exit(void)
2784 {
2785 	rtnl_unregister_all(PF_MPLS);
2786 	rtnl_af_unregister(&mpls_af_ops);
2787 	dev_remove_pack(&mpls_packet_type);
2788 	unregister_netdevice_notifier(&mpls_dev_notifier);
2789 	unregister_pernet_subsys(&mpls_net_ops);
2790 	ipgre_tunnel_encap_del_mpls_ops();
2791 }
2792 module_exit(mpls_exit);
2793 
2794 MODULE_DESCRIPTION("MultiProtocol Label Switching");
2795 MODULE_LICENSE("GPL v2");
2796 MODULE_ALIAS_NETPROTO(PF_MPLS);
2797