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1 #include <linux/types.h>
2 #include <linux/skbuff.h>
3 #include <linux/socket.h>
4 #include <linux/sysctl.h>
5 #include <linux/net.h>
6 #include <linux/module.h>
7 #include <linux/if_arp.h>
8 #include <linux/ipv6.h>
9 #include <linux/mpls.h>
10 #include <linux/nospec.h>
11 #include <linux/vmalloc.h>
12 #include <net/ip.h>
13 #include <net/dst.h>
14 #include <net/sock.h>
15 #include <net/arp.h>
16 #include <net/ip_fib.h>
17 #include <net/netevent.h>
18 #include <net/netns/generic.h>
19 #if IS_ENABLED(CONFIG_IPV6)
20 #include <net/ipv6.h>
21 #include <net/addrconf.h>
22 #endif
23 #include <net/nexthop.h>
24 #include "internal.h"
25 
26 /* Maximum number of labels to look ahead at when selecting a path of
27  * a multipath route
28  */
29 #define MAX_MP_SELECT_LABELS 4
30 
31 #define MPLS_NEIGH_TABLE_UNSPEC (NEIGH_LINK_TABLE + 1)
32 
33 static int zero = 0;
34 static int label_limit = (1 << 20) - 1;
35 
36 static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
37 		       struct nlmsghdr *nlh, struct net *net, u32 portid,
38 		       unsigned int nlm_flags);
39 
mpls_route_input_rcu(struct net * net,unsigned index)40 static struct mpls_route *mpls_route_input_rcu(struct net *net, unsigned index)
41 {
42 	struct mpls_route *rt = NULL;
43 
44 	if (index < net->mpls.platform_labels) {
45 		struct mpls_route __rcu **platform_label =
46 			rcu_dereference(net->mpls.platform_label);
47 		rt = rcu_dereference(platform_label[index]);
48 	}
49 	return rt;
50 }
51 
mpls_dev_get(const struct net_device * dev)52 static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
53 {
54 	return rcu_dereference_rtnl(dev->mpls_ptr);
55 }
56 
mpls_output_possible(const struct net_device * dev)57 bool mpls_output_possible(const struct net_device *dev)
58 {
59 	return dev && (dev->flags & IFF_UP) && netif_carrier_ok(dev);
60 }
61 EXPORT_SYMBOL_GPL(mpls_output_possible);
62 
__mpls_nh_via(struct mpls_route * rt,struct mpls_nh * nh)63 static u8 *__mpls_nh_via(struct mpls_route *rt, struct mpls_nh *nh)
64 {
65 	u8 *nh0_via = PTR_ALIGN((u8 *)&rt->rt_nh[rt->rt_nhn], VIA_ALEN_ALIGN);
66 	int nh_index = nh - rt->rt_nh;
67 
68 	return nh0_via + rt->rt_max_alen * nh_index;
69 }
70 
mpls_nh_via(const struct mpls_route * rt,const struct mpls_nh * nh)71 static const u8 *mpls_nh_via(const struct mpls_route *rt,
72 			     const struct mpls_nh *nh)
73 {
74 	return __mpls_nh_via((struct mpls_route *)rt, (struct mpls_nh *)nh);
75 }
76 
mpls_nh_header_size(const struct mpls_nh * nh)77 static unsigned int mpls_nh_header_size(const struct mpls_nh *nh)
78 {
79 	/* The size of the layer 2.5 labels to be added for this route */
80 	return nh->nh_labels * sizeof(struct mpls_shim_hdr);
81 }
82 
mpls_dev_mtu(const struct net_device * dev)83 unsigned int mpls_dev_mtu(const struct net_device *dev)
84 {
85 	/* The amount of data the layer 2 frame can hold */
86 	return dev->mtu;
87 }
88 EXPORT_SYMBOL_GPL(mpls_dev_mtu);
89 
mpls_pkt_too_big(const struct sk_buff * skb,unsigned int mtu)90 bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
91 {
92 	if (skb->len <= mtu)
93 		return false;
94 
95 	if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
96 		return false;
97 
98 	return true;
99 }
100 EXPORT_SYMBOL_GPL(mpls_pkt_too_big);
101 
mpls_multipath_hash(struct mpls_route * rt,struct sk_buff * skb)102 static u32 mpls_multipath_hash(struct mpls_route *rt, struct sk_buff *skb)
103 {
104 	struct mpls_entry_decoded dec;
105 	unsigned int mpls_hdr_len = 0;
106 	struct mpls_shim_hdr *hdr;
107 	bool eli_seen = false;
108 	int label_index;
109 	u32 hash = 0;
110 
111 	for (label_index = 0; label_index < MAX_MP_SELECT_LABELS;
112 	     label_index++) {
113 		mpls_hdr_len += sizeof(*hdr);
114 		if (!pskb_may_pull(skb, mpls_hdr_len))
115 			break;
116 
117 		/* Read and decode the current label */
118 		hdr = mpls_hdr(skb) + label_index;
119 		dec = mpls_entry_decode(hdr);
120 
121 		/* RFC6790 - reserved labels MUST NOT be used as keys
122 		 * for the load-balancing function
123 		 */
124 		if (likely(dec.label >= MPLS_LABEL_FIRST_UNRESERVED)) {
125 			hash = jhash_1word(dec.label, hash);
126 
127 			/* The entropy label follows the entropy label
128 			 * indicator, so this means that the entropy
129 			 * label was just added to the hash - no need to
130 			 * go any deeper either in the label stack or in the
131 			 * payload
132 			 */
133 			if (eli_seen)
134 				break;
135 		} else if (dec.label == MPLS_LABEL_ENTROPY) {
136 			eli_seen = true;
137 		}
138 
139 		if (!dec.bos)
140 			continue;
141 
142 		/* found bottom label; does skb have room for a header? */
143 		if (pskb_may_pull(skb, mpls_hdr_len + sizeof(struct iphdr))) {
144 			const struct iphdr *v4hdr;
145 
146 			v4hdr = (const struct iphdr *)(hdr + 1);
147 			if (v4hdr->version == 4) {
148 				hash = jhash_3words(ntohl(v4hdr->saddr),
149 						    ntohl(v4hdr->daddr),
150 						    v4hdr->protocol, hash);
151 			} else if (v4hdr->version == 6 &&
152 				   pskb_may_pull(skb, mpls_hdr_len +
153 						 sizeof(struct ipv6hdr))) {
154 				const struct ipv6hdr *v6hdr;
155 
156 				v6hdr = (const struct ipv6hdr *)(hdr + 1);
157 				hash = __ipv6_addr_jhash(&v6hdr->saddr, hash);
158 				hash = __ipv6_addr_jhash(&v6hdr->daddr, hash);
159 				hash = jhash_1word(v6hdr->nexthdr, hash);
160 			}
161 		}
162 
163 		break;
164 	}
165 
166 	return hash;
167 }
168 
mpls_select_multipath(struct mpls_route * rt,struct sk_buff * skb)169 static struct mpls_nh *mpls_select_multipath(struct mpls_route *rt,
170 					     struct sk_buff *skb)
171 {
172 	int alive = ACCESS_ONCE(rt->rt_nhn_alive);
173 	u32 hash = 0;
174 	int nh_index = 0;
175 	int n = 0;
176 
177 	/* No need to look further into packet if there's only
178 	 * one path
179 	 */
180 	if (rt->rt_nhn == 1)
181 		goto out;
182 
183 	if (alive <= 0)
184 		return NULL;
185 
186 	hash = mpls_multipath_hash(rt, skb);
187 	nh_index = hash % alive;
188 	if (alive == rt->rt_nhn)
189 		goto out;
190 	for_nexthops(rt) {
191 		if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
192 			continue;
193 		if (n == nh_index)
194 			return nh;
195 		n++;
196 	} endfor_nexthops(rt);
197 
198 out:
199 	return &rt->rt_nh[nh_index];
200 }
201 
mpls_egress(struct mpls_route * rt,struct sk_buff * skb,struct mpls_entry_decoded dec)202 static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
203 			struct mpls_entry_decoded dec)
204 {
205 	enum mpls_payload_type payload_type;
206 	bool success = false;
207 
208 	/* The IPv4 code below accesses through the IPv4 header
209 	 * checksum, which is 12 bytes into the packet.
210 	 * The IPv6 code below accesses through the IPv6 hop limit
211 	 * which is 8 bytes into the packet.
212 	 *
213 	 * For all supported cases there should always be at least 12
214 	 * bytes of packet data present.  The IPv4 header is 20 bytes
215 	 * without options and the IPv6 header is always 40 bytes
216 	 * long.
217 	 */
218 	if (!pskb_may_pull(skb, 12))
219 		return false;
220 
221 	payload_type = rt->rt_payload_type;
222 	if (payload_type == MPT_UNSPEC)
223 		payload_type = ip_hdr(skb)->version;
224 
225 	switch (payload_type) {
226 	case MPT_IPV4: {
227 		struct iphdr *hdr4 = ip_hdr(skb);
228 		skb->protocol = htons(ETH_P_IP);
229 		csum_replace2(&hdr4->check,
230 			      htons(hdr4->ttl << 8),
231 			      htons(dec.ttl << 8));
232 		hdr4->ttl = dec.ttl;
233 		success = true;
234 		break;
235 	}
236 	case MPT_IPV6: {
237 		struct ipv6hdr *hdr6 = ipv6_hdr(skb);
238 		skb->protocol = htons(ETH_P_IPV6);
239 		hdr6->hop_limit = dec.ttl;
240 		success = true;
241 		break;
242 	}
243 	case MPT_UNSPEC:
244 		break;
245 	}
246 
247 	return success;
248 }
249 
mpls_forward(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)250 static int mpls_forward(struct sk_buff *skb, struct net_device *dev,
251 			struct packet_type *pt, struct net_device *orig_dev)
252 {
253 	struct net *net = dev_net(dev);
254 	struct mpls_shim_hdr *hdr;
255 	struct mpls_route *rt;
256 	struct mpls_nh *nh;
257 	struct mpls_entry_decoded dec;
258 	struct net_device *out_dev;
259 	struct mpls_dev *mdev;
260 	unsigned int hh_len;
261 	unsigned int new_header_size;
262 	unsigned int mtu;
263 	int err;
264 
265 	/* Careful this entire function runs inside of an rcu critical section */
266 
267 	mdev = mpls_dev_get(dev);
268 	if (!mdev || !mdev->input_enabled)
269 		goto drop;
270 
271 	if (skb->pkt_type != PACKET_HOST)
272 		goto drop;
273 
274 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
275 		goto drop;
276 
277 	if (!pskb_may_pull(skb, sizeof(*hdr)))
278 		goto drop;
279 
280 	/* Read and decode the label */
281 	hdr = mpls_hdr(skb);
282 	dec = mpls_entry_decode(hdr);
283 
284 	rt = mpls_route_input_rcu(net, dec.label);
285 	if (!rt)
286 		goto drop;
287 
288 	nh = mpls_select_multipath(rt, skb);
289 	if (!nh)
290 		goto drop;
291 
292 	/* Find the output device */
293 	out_dev = rcu_dereference(nh->nh_dev);
294 	if (!mpls_output_possible(out_dev))
295 		goto drop;
296 
297 	/* Pop the label */
298 	skb_pull(skb, sizeof(*hdr));
299 	skb_reset_network_header(skb);
300 
301 	skb_orphan(skb);
302 
303 	if (skb_warn_if_lro(skb))
304 		goto drop;
305 
306 	skb_forward_csum(skb);
307 
308 	/* Verify ttl is valid */
309 	if (dec.ttl <= 1)
310 		goto drop;
311 	dec.ttl -= 1;
312 
313 	/* Verify the destination can hold the packet */
314 	new_header_size = mpls_nh_header_size(nh);
315 	mtu = mpls_dev_mtu(out_dev);
316 	if (mpls_pkt_too_big(skb, mtu - new_header_size))
317 		goto drop;
318 
319 	hh_len = LL_RESERVED_SPACE(out_dev);
320 	if (!out_dev->header_ops)
321 		hh_len = 0;
322 
323 	/* Ensure there is enough space for the headers in the skb */
324 	if (skb_cow(skb, hh_len + new_header_size))
325 		goto drop;
326 
327 	skb->dev = out_dev;
328 	skb->protocol = htons(ETH_P_MPLS_UC);
329 
330 	if (unlikely(!new_header_size && dec.bos)) {
331 		/* Penultimate hop popping */
332 		if (!mpls_egress(rt, skb, dec))
333 			goto drop;
334 	} else {
335 		bool bos;
336 		int i;
337 		skb_push(skb, new_header_size);
338 		skb_reset_network_header(skb);
339 		/* Push the new labels */
340 		hdr = mpls_hdr(skb);
341 		bos = dec.bos;
342 		for (i = nh->nh_labels - 1; i >= 0; i--) {
343 			hdr[i] = mpls_entry_encode(nh->nh_label[i],
344 						   dec.ttl, 0, bos);
345 			bos = false;
346 		}
347 	}
348 
349 	/* If via wasn't specified then send out using device address */
350 	if (nh->nh_via_table == MPLS_NEIGH_TABLE_UNSPEC)
351 		err = neigh_xmit(NEIGH_LINK_TABLE, out_dev,
352 				 out_dev->dev_addr, skb);
353 	else
354 		err = neigh_xmit(nh->nh_via_table, out_dev,
355 				 mpls_nh_via(rt, nh), skb);
356 	if (err)
357 		net_dbg_ratelimited("%s: packet transmission failed: %d\n",
358 				    __func__, err);
359 	return 0;
360 
361 drop:
362 	kfree_skb(skb);
363 	return NET_RX_DROP;
364 }
365 
366 static struct packet_type mpls_packet_type __read_mostly = {
367 	.type = cpu_to_be16(ETH_P_MPLS_UC),
368 	.func = mpls_forward,
369 };
370 
371 static const struct nla_policy rtm_mpls_policy[RTA_MAX+1] = {
372 	[RTA_DST]		= { .type = NLA_U32 },
373 	[RTA_OIF]		= { .type = NLA_U32 },
374 };
375 
376 struct mpls_route_config {
377 	u32			rc_protocol;
378 	u32			rc_ifindex;
379 	u8			rc_via_table;
380 	u8			rc_via_alen;
381 	u8			rc_via[MAX_VIA_ALEN];
382 	u32			rc_label;
383 	u8			rc_output_labels;
384 	u32			rc_output_label[MAX_NEW_LABELS];
385 	u32			rc_nlflags;
386 	enum mpls_payload_type	rc_payload_type;
387 	struct nl_info		rc_nlinfo;
388 	struct rtnexthop	*rc_mp;
389 	int			rc_mp_len;
390 };
391 
mpls_rt_alloc(int num_nh,u8 max_alen)392 static struct mpls_route *mpls_rt_alloc(int num_nh, u8 max_alen)
393 {
394 	u8 max_alen_aligned = ALIGN(max_alen, VIA_ALEN_ALIGN);
395 	struct mpls_route *rt;
396 
397 	rt = kzalloc(ALIGN(sizeof(*rt) + num_nh * sizeof(*rt->rt_nh),
398 			   VIA_ALEN_ALIGN) +
399 		     num_nh * max_alen_aligned,
400 		     GFP_KERNEL);
401 	if (rt) {
402 		rt->rt_nhn = num_nh;
403 		rt->rt_nhn_alive = num_nh;
404 		rt->rt_max_alen = max_alen_aligned;
405 	}
406 
407 	return rt;
408 }
409 
mpls_rt_free(struct mpls_route * rt)410 static void mpls_rt_free(struct mpls_route *rt)
411 {
412 	if (rt)
413 		kfree_rcu(rt, rt_rcu);
414 }
415 
mpls_notify_route(struct net * net,unsigned index,struct mpls_route * old,struct mpls_route * new,const struct nl_info * info)416 static void mpls_notify_route(struct net *net, unsigned index,
417 			      struct mpls_route *old, struct mpls_route *new,
418 			      const struct nl_info *info)
419 {
420 	struct nlmsghdr *nlh = info ? info->nlh : NULL;
421 	unsigned portid = info ? info->portid : 0;
422 	int event = new ? RTM_NEWROUTE : RTM_DELROUTE;
423 	struct mpls_route *rt = new ? new : old;
424 	unsigned nlm_flags = (old && new) ? NLM_F_REPLACE : 0;
425 	/* Ignore reserved labels for now */
426 	if (rt && (index >= MPLS_LABEL_FIRST_UNRESERVED))
427 		rtmsg_lfib(event, index, rt, nlh, net, portid, nlm_flags);
428 }
429 
mpls_route_update(struct net * net,unsigned index,struct mpls_route * new,const struct nl_info * info)430 static void mpls_route_update(struct net *net, unsigned index,
431 			      struct mpls_route *new,
432 			      const struct nl_info *info)
433 {
434 	struct mpls_route __rcu **platform_label;
435 	struct mpls_route *rt;
436 
437 	ASSERT_RTNL();
438 
439 	platform_label = rtnl_dereference(net->mpls.platform_label);
440 	rt = rtnl_dereference(platform_label[index]);
441 	rcu_assign_pointer(platform_label[index], new);
442 
443 	mpls_notify_route(net, index, rt, new, info);
444 
445 	/* If we removed a route free it now */
446 	mpls_rt_free(rt);
447 }
448 
find_free_label(struct net * net)449 static unsigned find_free_label(struct net *net)
450 {
451 	struct mpls_route __rcu **platform_label;
452 	size_t platform_labels;
453 	unsigned index;
454 
455 	platform_label = rtnl_dereference(net->mpls.platform_label);
456 	platform_labels = net->mpls.platform_labels;
457 	for (index = MPLS_LABEL_FIRST_UNRESERVED; index < platform_labels;
458 	     index++) {
459 		if (!rtnl_dereference(platform_label[index]))
460 			return index;
461 	}
462 	return LABEL_NOT_SPECIFIED;
463 }
464 
465 #if IS_ENABLED(CONFIG_INET)
inet_fib_lookup_dev(struct net * net,const void * addr)466 static struct net_device *inet_fib_lookup_dev(struct net *net,
467 					      const void *addr)
468 {
469 	struct net_device *dev;
470 	struct rtable *rt;
471 	struct in_addr daddr;
472 
473 	memcpy(&daddr, addr, sizeof(struct in_addr));
474 	rt = ip_route_output(net, daddr.s_addr, 0, 0, 0);
475 	if (IS_ERR(rt))
476 		return ERR_CAST(rt);
477 
478 	dev = rt->dst.dev;
479 	dev_hold(dev);
480 
481 	ip_rt_put(rt);
482 
483 	return dev;
484 }
485 #else
inet_fib_lookup_dev(struct net * net,const void * addr)486 static struct net_device *inet_fib_lookup_dev(struct net *net,
487 					      const void *addr)
488 {
489 	return ERR_PTR(-EAFNOSUPPORT);
490 }
491 #endif
492 
493 #if IS_ENABLED(CONFIG_IPV6)
inet6_fib_lookup_dev(struct net * net,const void * addr)494 static struct net_device *inet6_fib_lookup_dev(struct net *net,
495 					       const void *addr)
496 {
497 	struct net_device *dev;
498 	struct dst_entry *dst;
499 	struct flowi6 fl6;
500 	int err;
501 
502 	if (!ipv6_stub)
503 		return ERR_PTR(-EAFNOSUPPORT);
504 
505 	memset(&fl6, 0, sizeof(fl6));
506 	memcpy(&fl6.daddr, addr, sizeof(struct in6_addr));
507 	err = ipv6_stub->ipv6_dst_lookup(net, NULL, &dst, &fl6);
508 	if (err)
509 		return ERR_PTR(err);
510 
511 	dev = dst->dev;
512 	dev_hold(dev);
513 	dst_release(dst);
514 
515 	return dev;
516 }
517 #else
inet6_fib_lookup_dev(struct net * net,const void * addr)518 static struct net_device *inet6_fib_lookup_dev(struct net *net,
519 					       const void *addr)
520 {
521 	return ERR_PTR(-EAFNOSUPPORT);
522 }
523 #endif
524 
find_outdev(struct net * net,struct mpls_route * rt,struct mpls_nh * nh,int oif)525 static struct net_device *find_outdev(struct net *net,
526 				      struct mpls_route *rt,
527 				      struct mpls_nh *nh, int oif)
528 {
529 	struct net_device *dev = NULL;
530 
531 	if (!oif) {
532 		switch (nh->nh_via_table) {
533 		case NEIGH_ARP_TABLE:
534 			dev = inet_fib_lookup_dev(net, mpls_nh_via(rt, nh));
535 			break;
536 		case NEIGH_ND_TABLE:
537 			dev = inet6_fib_lookup_dev(net, mpls_nh_via(rt, nh));
538 			break;
539 		case NEIGH_LINK_TABLE:
540 			break;
541 		}
542 	} else {
543 		dev = dev_get_by_index(net, oif);
544 	}
545 
546 	if (!dev)
547 		return ERR_PTR(-ENODEV);
548 
549 	if (IS_ERR(dev))
550 		return dev;
551 
552 	/* The caller is holding rtnl anyways, so release the dev reference */
553 	dev_put(dev);
554 
555 	return dev;
556 }
557 
mpls_nh_assign_dev(struct net * net,struct mpls_route * rt,struct mpls_nh * nh,int oif)558 static int mpls_nh_assign_dev(struct net *net, struct mpls_route *rt,
559 			      struct mpls_nh *nh, int oif)
560 {
561 	struct net_device *dev = NULL;
562 	int err = -ENODEV;
563 
564 	dev = find_outdev(net, rt, nh, oif);
565 	if (IS_ERR(dev)) {
566 		err = PTR_ERR(dev);
567 		dev = NULL;
568 		goto errout;
569 	}
570 
571 	/* Ensure this is a supported device */
572 	err = -EINVAL;
573 	if (!mpls_dev_get(dev))
574 		goto errout;
575 
576 	if ((nh->nh_via_table == NEIGH_LINK_TABLE) &&
577 	    (dev->addr_len != nh->nh_via_alen))
578 		goto errout;
579 
580 	RCU_INIT_POINTER(nh->nh_dev, dev);
581 
582 	if (!(dev->flags & IFF_UP)) {
583 		nh->nh_flags |= RTNH_F_DEAD;
584 	} else {
585 		unsigned int flags;
586 
587 		flags = dev_get_flags(dev);
588 		if (!(flags & (IFF_RUNNING | IFF_LOWER_UP)))
589 			nh->nh_flags |= RTNH_F_LINKDOWN;
590 	}
591 
592 	return 0;
593 
594 errout:
595 	return err;
596 }
597 
mpls_nh_build_from_cfg(struct mpls_route_config * cfg,struct mpls_route * rt)598 static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
599 				  struct mpls_route *rt)
600 {
601 	struct net *net = cfg->rc_nlinfo.nl_net;
602 	struct mpls_nh *nh = rt->rt_nh;
603 	int err;
604 	int i;
605 
606 	if (!nh)
607 		return -ENOMEM;
608 
609 	err = -EINVAL;
610 	/* Ensure only a supported number of labels are present */
611 	if (cfg->rc_output_labels > MAX_NEW_LABELS)
612 		goto errout;
613 
614 	nh->nh_labels = cfg->rc_output_labels;
615 	for (i = 0; i < nh->nh_labels; i++)
616 		nh->nh_label[i] = cfg->rc_output_label[i];
617 
618 	nh->nh_via_table = cfg->rc_via_table;
619 	memcpy(__mpls_nh_via(rt, nh), cfg->rc_via, cfg->rc_via_alen);
620 	nh->nh_via_alen = cfg->rc_via_alen;
621 
622 	err = mpls_nh_assign_dev(net, rt, nh, cfg->rc_ifindex);
623 	if (err)
624 		goto errout;
625 
626 	if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
627 		rt->rt_nhn_alive--;
628 
629 	return 0;
630 
631 errout:
632 	return err;
633 }
634 
mpls_nh_build(struct net * net,struct mpls_route * rt,struct mpls_nh * nh,int oif,struct nlattr * via,struct nlattr * newdst)635 static int mpls_nh_build(struct net *net, struct mpls_route *rt,
636 			 struct mpls_nh *nh, int oif, struct nlattr *via,
637 			 struct nlattr *newdst)
638 {
639 	int err = -ENOMEM;
640 
641 	if (!nh)
642 		goto errout;
643 
644 	if (newdst) {
645 		err = nla_get_labels(newdst, MAX_NEW_LABELS,
646 				     &nh->nh_labels, nh->nh_label);
647 		if (err)
648 			goto errout;
649 	}
650 
651 	if (via) {
652 		err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
653 				  __mpls_nh_via(rt, nh));
654 		if (err)
655 			goto errout;
656 	} else {
657 		nh->nh_via_table = MPLS_NEIGH_TABLE_UNSPEC;
658 	}
659 
660 	err = mpls_nh_assign_dev(net, rt, nh, oif);
661 	if (err)
662 		goto errout;
663 
664 	return 0;
665 
666 errout:
667 	return err;
668 }
669 
mpls_count_nexthops(struct rtnexthop * rtnh,int len,u8 cfg_via_alen,u8 * max_via_alen)670 static int mpls_count_nexthops(struct rtnexthop *rtnh, int len,
671 			       u8 cfg_via_alen, u8 *max_via_alen)
672 {
673 	int nhs = 0;
674 	int remaining = len;
675 
676 	if (!rtnh) {
677 		*max_via_alen = cfg_via_alen;
678 		return 1;
679 	}
680 
681 	*max_via_alen = 0;
682 
683 	while (rtnh_ok(rtnh, remaining)) {
684 		struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
685 		int attrlen;
686 
687 		attrlen = rtnh_attrlen(rtnh);
688 		nla = nla_find(attrs, attrlen, RTA_VIA);
689 		if (nla && nla_len(nla) >=
690 		    offsetof(struct rtvia, rtvia_addr)) {
691 			int via_alen = nla_len(nla) -
692 				offsetof(struct rtvia, rtvia_addr);
693 
694 			if (via_alen <= MAX_VIA_ALEN)
695 				*max_via_alen = max_t(u16, *max_via_alen,
696 						      via_alen);
697 		}
698 
699 		nhs++;
700 		rtnh = rtnh_next(rtnh, &remaining);
701 	}
702 
703 	/* leftover implies invalid nexthop configuration, discard it */
704 	return remaining > 0 ? 0 : nhs;
705 }
706 
mpls_nh_build_multi(struct mpls_route_config * cfg,struct mpls_route * rt)707 static int mpls_nh_build_multi(struct mpls_route_config *cfg,
708 			       struct mpls_route *rt)
709 {
710 	struct rtnexthop *rtnh = cfg->rc_mp;
711 	struct nlattr *nla_via, *nla_newdst;
712 	int remaining = cfg->rc_mp_len;
713 	int nhs = 0;
714 	int err = 0;
715 
716 	change_nexthops(rt) {
717 		int attrlen;
718 
719 		nla_via = NULL;
720 		nla_newdst = NULL;
721 
722 		err = -EINVAL;
723 		if (!rtnh_ok(rtnh, remaining))
724 			goto errout;
725 
726 		/* neither weighted multipath nor any flags
727 		 * are supported
728 		 */
729 		if (rtnh->rtnh_hops || rtnh->rtnh_flags)
730 			goto errout;
731 
732 		attrlen = rtnh_attrlen(rtnh);
733 		if (attrlen > 0) {
734 			struct nlattr *attrs = rtnh_attrs(rtnh);
735 
736 			nla_via = nla_find(attrs, attrlen, RTA_VIA);
737 			nla_newdst = nla_find(attrs, attrlen, RTA_NEWDST);
738 		}
739 
740 		err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh,
741 				    rtnh->rtnh_ifindex, nla_via, nla_newdst);
742 		if (err)
743 			goto errout;
744 
745 		if (nh->nh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
746 			rt->rt_nhn_alive--;
747 
748 		rtnh = rtnh_next(rtnh, &remaining);
749 		nhs++;
750 	} endfor_nexthops(rt);
751 
752 	rt->rt_nhn = nhs;
753 
754 	return 0;
755 
756 errout:
757 	return err;
758 }
759 
mpls_label_ok(struct net * net,unsigned int * index)760 static bool mpls_label_ok(struct net *net, unsigned int *index)
761 {
762 	bool is_ok = true;
763 
764 	/* Reserved labels may not be set */
765 	if (*index < MPLS_LABEL_FIRST_UNRESERVED)
766 		is_ok = false;
767 
768 	/* The full 20 bit range may not be supported. */
769 	if (is_ok && *index >= net->mpls.platform_labels)
770 		is_ok = false;
771 
772 	*index = array_index_nospec(*index, net->mpls.platform_labels);
773 	return is_ok;
774 }
775 
mpls_route_add(struct mpls_route_config * cfg)776 static int mpls_route_add(struct mpls_route_config *cfg)
777 {
778 	struct mpls_route __rcu **platform_label;
779 	struct net *net = cfg->rc_nlinfo.nl_net;
780 	struct mpls_route *rt, *old;
781 	int err = -EINVAL;
782 	u8 max_via_alen;
783 	unsigned index;
784 	int nhs;
785 
786 	index = cfg->rc_label;
787 
788 	/* If a label was not specified during insert pick one */
789 	if ((index == LABEL_NOT_SPECIFIED) &&
790 	    (cfg->rc_nlflags & NLM_F_CREATE)) {
791 		index = find_free_label(net);
792 	}
793 
794 	if (!mpls_label_ok(net, &index))
795 		goto errout;
796 
797 	/* Append makes no sense with mpls */
798 	err = -EOPNOTSUPP;
799 	if (cfg->rc_nlflags & NLM_F_APPEND)
800 		goto errout;
801 
802 	err = -EEXIST;
803 	platform_label = rtnl_dereference(net->mpls.platform_label);
804 	old = rtnl_dereference(platform_label[index]);
805 	if ((cfg->rc_nlflags & NLM_F_EXCL) && old)
806 		goto errout;
807 
808 	err = -EEXIST;
809 	if (!(cfg->rc_nlflags & NLM_F_REPLACE) && old)
810 		goto errout;
811 
812 	err = -ENOENT;
813 	if (!(cfg->rc_nlflags & NLM_F_CREATE) && !old)
814 		goto errout;
815 
816 	err = -EINVAL;
817 	nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len,
818 				  cfg->rc_via_alen, &max_via_alen);
819 	if (nhs == 0)
820 		goto errout;
821 
822 	err = -ENOMEM;
823 	rt = mpls_rt_alloc(nhs, max_via_alen);
824 	if (!rt)
825 		goto errout;
826 
827 	rt->rt_protocol = cfg->rc_protocol;
828 	rt->rt_payload_type = cfg->rc_payload_type;
829 
830 	if (cfg->rc_mp)
831 		err = mpls_nh_build_multi(cfg, rt);
832 	else
833 		err = mpls_nh_build_from_cfg(cfg, rt);
834 	if (err)
835 		goto freert;
836 
837 	mpls_route_update(net, index, rt, &cfg->rc_nlinfo);
838 
839 	return 0;
840 
841 freert:
842 	mpls_rt_free(rt);
843 errout:
844 	return err;
845 }
846 
mpls_route_del(struct mpls_route_config * cfg)847 static int mpls_route_del(struct mpls_route_config *cfg)
848 {
849 	struct net *net = cfg->rc_nlinfo.nl_net;
850 	unsigned index;
851 	int err = -EINVAL;
852 
853 	index = cfg->rc_label;
854 
855 	if (!mpls_label_ok(net, &index))
856 		goto errout;
857 
858 	mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
859 
860 	err = 0;
861 errout:
862 	return err;
863 }
864 
865 #define MPLS_PERDEV_SYSCTL_OFFSET(field)	\
866 	(&((struct mpls_dev *)0)->field)
867 
868 static const struct ctl_table mpls_dev_table[] = {
869 	{
870 		.procname	= "input",
871 		.maxlen		= sizeof(int),
872 		.mode		= 0644,
873 		.proc_handler	= proc_dointvec,
874 		.data		= MPLS_PERDEV_SYSCTL_OFFSET(input_enabled),
875 	},
876 	{ }
877 };
878 
mpls_dev_sysctl_register(struct net_device * dev,struct mpls_dev * mdev)879 static int mpls_dev_sysctl_register(struct net_device *dev,
880 				    struct mpls_dev *mdev)
881 {
882 	char path[sizeof("net/mpls/conf/") + IFNAMSIZ];
883 	struct ctl_table *table;
884 	int i;
885 
886 	table = kmemdup(&mpls_dev_table, sizeof(mpls_dev_table), GFP_KERNEL);
887 	if (!table)
888 		goto out;
889 
890 	/* Table data contains only offsets relative to the base of
891 	 * the mdev at this point, so make them absolute.
892 	 */
893 	for (i = 0; i < ARRAY_SIZE(mpls_dev_table); i++)
894 		table[i].data = (char *)mdev + (uintptr_t)table[i].data;
895 
896 	snprintf(path, sizeof(path), "net/mpls/conf/%s", dev->name);
897 
898 	mdev->sysctl = register_net_sysctl(dev_net(dev), path, table);
899 	if (!mdev->sysctl)
900 		goto free;
901 
902 	return 0;
903 
904 free:
905 	kfree(table);
906 out:
907 	return -ENOBUFS;
908 }
909 
mpls_dev_sysctl_unregister(struct mpls_dev * mdev)910 static void mpls_dev_sysctl_unregister(struct mpls_dev *mdev)
911 {
912 	struct ctl_table *table;
913 
914 	table = mdev->sysctl->ctl_table_arg;
915 	unregister_net_sysctl_table(mdev->sysctl);
916 	kfree(table);
917 }
918 
mpls_add_dev(struct net_device * dev)919 static struct mpls_dev *mpls_add_dev(struct net_device *dev)
920 {
921 	struct mpls_dev *mdev;
922 	int err = -ENOMEM;
923 
924 	ASSERT_RTNL();
925 
926 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
927 	if (!mdev)
928 		return ERR_PTR(err);
929 
930 	err = mpls_dev_sysctl_register(dev, mdev);
931 	if (err)
932 		goto free;
933 
934 	rcu_assign_pointer(dev->mpls_ptr, mdev);
935 
936 	return mdev;
937 
938 free:
939 	kfree(mdev);
940 	return ERR_PTR(err);
941 }
942 
mpls_ifdown(struct net_device * dev,int event)943 static void mpls_ifdown(struct net_device *dev, int event)
944 {
945 	struct mpls_route __rcu **platform_label;
946 	struct net *net = dev_net(dev);
947 	unsigned int nh_flags = RTNH_F_DEAD | RTNH_F_LINKDOWN;
948 	unsigned int alive;
949 	unsigned index;
950 
951 	platform_label = rtnl_dereference(net->mpls.platform_label);
952 	for (index = 0; index < net->mpls.platform_labels; index++) {
953 		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
954 
955 		if (!rt)
956 			continue;
957 
958 		alive = 0;
959 		change_nexthops(rt) {
960 			if (rtnl_dereference(nh->nh_dev) != dev)
961 				goto next;
962 
963 			switch (event) {
964 			case NETDEV_DOWN:
965 			case NETDEV_UNREGISTER:
966 				nh->nh_flags |= RTNH_F_DEAD;
967 				/* fall through */
968 			case NETDEV_CHANGE:
969 				nh->nh_flags |= RTNH_F_LINKDOWN;
970 				break;
971 			}
972 			if (event == NETDEV_UNREGISTER)
973 				RCU_INIT_POINTER(nh->nh_dev, NULL);
974 next:
975 			if (!(nh->nh_flags & nh_flags))
976 				alive++;
977 		} endfor_nexthops(rt);
978 
979 		WRITE_ONCE(rt->rt_nhn_alive, alive);
980 	}
981 }
982 
mpls_ifup(struct net_device * dev,unsigned int nh_flags)983 static void mpls_ifup(struct net_device *dev, unsigned int nh_flags)
984 {
985 	struct mpls_route __rcu **platform_label;
986 	struct net *net = dev_net(dev);
987 	unsigned index;
988 	int alive;
989 
990 	platform_label = rtnl_dereference(net->mpls.platform_label);
991 	for (index = 0; index < net->mpls.platform_labels; index++) {
992 		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
993 
994 		if (!rt)
995 			continue;
996 
997 		alive = 0;
998 		change_nexthops(rt) {
999 			struct net_device *nh_dev =
1000 				rtnl_dereference(nh->nh_dev);
1001 
1002 			if (!(nh->nh_flags & nh_flags)) {
1003 				alive++;
1004 				continue;
1005 			}
1006 			if (nh_dev != dev)
1007 				continue;
1008 			alive++;
1009 			nh->nh_flags &= ~nh_flags;
1010 		} endfor_nexthops(rt);
1011 
1012 		ACCESS_ONCE(rt->rt_nhn_alive) = alive;
1013 	}
1014 }
1015 
mpls_dev_notify(struct notifier_block * this,unsigned long event,void * ptr)1016 static int mpls_dev_notify(struct notifier_block *this, unsigned long event,
1017 			   void *ptr)
1018 {
1019 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1020 	struct mpls_dev *mdev;
1021 	unsigned int flags;
1022 
1023 	if (event == NETDEV_REGISTER) {
1024 		/* For now just support Ethernet, IPGRE, SIT and IPIP devices */
1025 		if (dev->type == ARPHRD_ETHER ||
1026 		    dev->type == ARPHRD_LOOPBACK ||
1027 		    dev->type == ARPHRD_IPGRE ||
1028 		    dev->type == ARPHRD_SIT ||
1029 		    dev->type == ARPHRD_TUNNEL) {
1030 			mdev = mpls_add_dev(dev);
1031 			if (IS_ERR(mdev))
1032 				return notifier_from_errno(PTR_ERR(mdev));
1033 		}
1034 		return NOTIFY_OK;
1035 	}
1036 
1037 	mdev = mpls_dev_get(dev);
1038 	if (!mdev)
1039 		return NOTIFY_OK;
1040 
1041 	switch (event) {
1042 	case NETDEV_DOWN:
1043 		mpls_ifdown(dev, event);
1044 		break;
1045 	case NETDEV_UP:
1046 		flags = dev_get_flags(dev);
1047 		if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1048 			mpls_ifup(dev, RTNH_F_DEAD | RTNH_F_LINKDOWN);
1049 		else
1050 			mpls_ifup(dev, RTNH_F_DEAD);
1051 		break;
1052 	case NETDEV_CHANGE:
1053 		flags = dev_get_flags(dev);
1054 		if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1055 			mpls_ifup(dev, RTNH_F_DEAD | RTNH_F_LINKDOWN);
1056 		else
1057 			mpls_ifdown(dev, event);
1058 		break;
1059 	case NETDEV_UNREGISTER:
1060 		mpls_ifdown(dev, event);
1061 		mdev = mpls_dev_get(dev);
1062 		if (mdev) {
1063 			mpls_dev_sysctl_unregister(mdev);
1064 			RCU_INIT_POINTER(dev->mpls_ptr, NULL);
1065 			kfree_rcu(mdev, rcu);
1066 		}
1067 		break;
1068 	case NETDEV_CHANGENAME:
1069 		mdev = mpls_dev_get(dev);
1070 		if (mdev) {
1071 			int err;
1072 
1073 			mpls_dev_sysctl_unregister(mdev);
1074 			err = mpls_dev_sysctl_register(dev, mdev);
1075 			if (err)
1076 				return notifier_from_errno(err);
1077 		}
1078 		break;
1079 	}
1080 	return NOTIFY_OK;
1081 }
1082 
1083 static struct notifier_block mpls_dev_notifier = {
1084 	.notifier_call = mpls_dev_notify,
1085 };
1086 
nla_put_via(struct sk_buff * skb,u8 table,const void * addr,int alen)1087 static int nla_put_via(struct sk_buff *skb,
1088 		       u8 table, const void *addr, int alen)
1089 {
1090 	static const int table_to_family[NEIGH_NR_TABLES + 1] = {
1091 		AF_INET, AF_INET6, AF_DECnet, AF_PACKET,
1092 	};
1093 	struct nlattr *nla;
1094 	struct rtvia *via;
1095 	int family = AF_UNSPEC;
1096 
1097 	nla = nla_reserve(skb, RTA_VIA, alen + 2);
1098 	if (!nla)
1099 		return -EMSGSIZE;
1100 
1101 	if (table <= NEIGH_NR_TABLES)
1102 		family = table_to_family[table];
1103 
1104 	via = nla_data(nla);
1105 	via->rtvia_family = family;
1106 	memcpy(via->rtvia_addr, addr, alen);
1107 	return 0;
1108 }
1109 
nla_put_labels(struct sk_buff * skb,int attrtype,u8 labels,const u32 label[])1110 int nla_put_labels(struct sk_buff *skb, int attrtype,
1111 		   u8 labels, const u32 label[])
1112 {
1113 	struct nlattr *nla;
1114 	struct mpls_shim_hdr *nla_label;
1115 	bool bos;
1116 	int i;
1117 	nla = nla_reserve(skb, attrtype, labels*4);
1118 	if (!nla)
1119 		return -EMSGSIZE;
1120 
1121 	nla_label = nla_data(nla);
1122 	bos = true;
1123 	for (i = labels - 1; i >= 0; i--) {
1124 		nla_label[i] = mpls_entry_encode(label[i], 0, 0, bos);
1125 		bos = false;
1126 	}
1127 
1128 	return 0;
1129 }
1130 EXPORT_SYMBOL_GPL(nla_put_labels);
1131 
nla_get_labels(const struct nlattr * nla,u32 max_labels,u8 * labels,u32 label[])1132 int nla_get_labels(const struct nlattr *nla,
1133 		   u32 max_labels, u8 *labels, u32 label[])
1134 {
1135 	unsigned len = nla_len(nla);
1136 	unsigned nla_labels;
1137 	struct mpls_shim_hdr *nla_label;
1138 	bool bos;
1139 	int i;
1140 
1141 	/* len needs to be an even multiple of 4 (the label size) */
1142 	if (len & 3)
1143 		return -EINVAL;
1144 
1145 	/* Limit the number of new labels allowed */
1146 	nla_labels = len/4;
1147 	if (nla_labels > max_labels)
1148 		return -EINVAL;
1149 
1150 	nla_label = nla_data(nla);
1151 	bos = true;
1152 	for (i = nla_labels - 1; i >= 0; i--, bos = false) {
1153 		struct mpls_entry_decoded dec;
1154 		dec = mpls_entry_decode(nla_label + i);
1155 
1156 		/* Ensure the bottom of stack flag is properly set
1157 		 * and ttl and tc are both clear.
1158 		 */
1159 		if ((dec.bos != bos) || dec.ttl || dec.tc)
1160 			return -EINVAL;
1161 
1162 		switch (dec.label) {
1163 		case MPLS_LABEL_IMPLNULL:
1164 			/* RFC3032: This is a label that an LSR may
1165 			 * assign and distribute, but which never
1166 			 * actually appears in the encapsulation.
1167 			 */
1168 			return -EINVAL;
1169 		}
1170 
1171 		label[i] = dec.label;
1172 	}
1173 	*labels = nla_labels;
1174 	return 0;
1175 }
1176 EXPORT_SYMBOL_GPL(nla_get_labels);
1177 
nla_get_via(const struct nlattr * nla,u8 * via_alen,u8 * via_table,u8 via_addr[])1178 int nla_get_via(const struct nlattr *nla, u8 *via_alen,
1179 		u8 *via_table, u8 via_addr[])
1180 {
1181 	struct rtvia *via = nla_data(nla);
1182 	int err = -EINVAL;
1183 	int alen;
1184 
1185 	if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
1186 		goto errout;
1187 	alen = nla_len(nla) -
1188 			offsetof(struct rtvia, rtvia_addr);
1189 	if (alen > MAX_VIA_ALEN)
1190 		goto errout;
1191 
1192 	/* Validate the address family */
1193 	switch (via->rtvia_family) {
1194 	case AF_PACKET:
1195 		*via_table = NEIGH_LINK_TABLE;
1196 		break;
1197 	case AF_INET:
1198 		*via_table = NEIGH_ARP_TABLE;
1199 		if (alen != 4)
1200 			goto errout;
1201 		break;
1202 	case AF_INET6:
1203 		*via_table = NEIGH_ND_TABLE;
1204 		if (alen != 16)
1205 			goto errout;
1206 		break;
1207 	default:
1208 		/* Unsupported address family */
1209 		goto errout;
1210 	}
1211 
1212 	memcpy(via_addr, via->rtvia_addr, alen);
1213 	*via_alen = alen;
1214 	err = 0;
1215 
1216 errout:
1217 	return err;
1218 }
1219 
rtm_to_route_config(struct sk_buff * skb,struct nlmsghdr * nlh,struct mpls_route_config * cfg)1220 static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
1221 			       struct mpls_route_config *cfg)
1222 {
1223 	struct rtmsg *rtm;
1224 	struct nlattr *tb[RTA_MAX+1];
1225 	int index;
1226 	int err;
1227 
1228 	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_mpls_policy);
1229 	if (err < 0)
1230 		goto errout;
1231 
1232 	err = -EINVAL;
1233 	rtm = nlmsg_data(nlh);
1234 	memset(cfg, 0, sizeof(*cfg));
1235 
1236 	if (rtm->rtm_family != AF_MPLS)
1237 		goto errout;
1238 	if (rtm->rtm_dst_len != 20)
1239 		goto errout;
1240 	if (rtm->rtm_src_len != 0)
1241 		goto errout;
1242 	if (rtm->rtm_tos != 0)
1243 		goto errout;
1244 	if (rtm->rtm_table != RT_TABLE_MAIN)
1245 		goto errout;
1246 	/* Any value is acceptable for rtm_protocol */
1247 
1248 	/* As mpls uses destination specific addresses
1249 	 * (or source specific address in the case of multicast)
1250 	 * all addresses have universal scope.
1251 	 */
1252 	if (rtm->rtm_scope != RT_SCOPE_UNIVERSE)
1253 		goto errout;
1254 	if (rtm->rtm_type != RTN_UNICAST)
1255 		goto errout;
1256 	if (rtm->rtm_flags != 0)
1257 		goto errout;
1258 
1259 	cfg->rc_label		= LABEL_NOT_SPECIFIED;
1260 	cfg->rc_protocol	= rtm->rtm_protocol;
1261 	cfg->rc_via_table	= MPLS_NEIGH_TABLE_UNSPEC;
1262 	cfg->rc_nlflags		= nlh->nlmsg_flags;
1263 	cfg->rc_nlinfo.portid	= NETLINK_CB(skb).portid;
1264 	cfg->rc_nlinfo.nlh	= nlh;
1265 	cfg->rc_nlinfo.nl_net	= sock_net(skb->sk);
1266 
1267 	for (index = 0; index <= RTA_MAX; index++) {
1268 		struct nlattr *nla = tb[index];
1269 		if (!nla)
1270 			continue;
1271 
1272 		switch (index) {
1273 		case RTA_OIF:
1274 			cfg->rc_ifindex = nla_get_u32(nla);
1275 			break;
1276 		case RTA_NEWDST:
1277 			if (nla_get_labels(nla, MAX_NEW_LABELS,
1278 					   &cfg->rc_output_labels,
1279 					   cfg->rc_output_label))
1280 				goto errout;
1281 			break;
1282 		case RTA_DST:
1283 		{
1284 			u8 label_count;
1285 			if (nla_get_labels(nla, 1, &label_count,
1286 					   &cfg->rc_label))
1287 				goto errout;
1288 
1289 			if (!mpls_label_ok(cfg->rc_nlinfo.nl_net,
1290 					   &cfg->rc_label))
1291 				goto errout;
1292 			break;
1293 		}
1294 		case RTA_VIA:
1295 		{
1296 			if (nla_get_via(nla, &cfg->rc_via_alen,
1297 					&cfg->rc_via_table, cfg->rc_via))
1298 				goto errout;
1299 			break;
1300 		}
1301 		case RTA_MULTIPATH:
1302 		{
1303 			cfg->rc_mp = nla_data(nla);
1304 			cfg->rc_mp_len = nla_len(nla);
1305 			break;
1306 		}
1307 		default:
1308 			/* Unsupported attribute */
1309 			goto errout;
1310 		}
1311 	}
1312 
1313 	err = 0;
1314 errout:
1315 	return err;
1316 }
1317 
mpls_rtm_delroute(struct sk_buff * skb,struct nlmsghdr * nlh)1318 static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
1319 {
1320 	struct mpls_route_config cfg;
1321 	int err;
1322 
1323 	err = rtm_to_route_config(skb, nlh, &cfg);
1324 	if (err < 0)
1325 		return err;
1326 
1327 	return mpls_route_del(&cfg);
1328 }
1329 
1330 
mpls_rtm_newroute(struct sk_buff * skb,struct nlmsghdr * nlh)1331 static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
1332 {
1333 	struct mpls_route_config cfg;
1334 	int err;
1335 
1336 	err = rtm_to_route_config(skb, nlh, &cfg);
1337 	if (err < 0)
1338 		return err;
1339 
1340 	return mpls_route_add(&cfg);
1341 }
1342 
mpls_dump_route(struct sk_buff * skb,u32 portid,u32 seq,int event,u32 label,struct mpls_route * rt,int flags)1343 static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
1344 			   u32 label, struct mpls_route *rt, int flags)
1345 {
1346 	struct net_device *dev;
1347 	struct nlmsghdr *nlh;
1348 	struct rtmsg *rtm;
1349 
1350 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1351 	if (nlh == NULL)
1352 		return -EMSGSIZE;
1353 
1354 	rtm = nlmsg_data(nlh);
1355 	rtm->rtm_family = AF_MPLS;
1356 	rtm->rtm_dst_len = 20;
1357 	rtm->rtm_src_len = 0;
1358 	rtm->rtm_tos = 0;
1359 	rtm->rtm_table = RT_TABLE_MAIN;
1360 	rtm->rtm_protocol = rt->rt_protocol;
1361 	rtm->rtm_scope = RT_SCOPE_UNIVERSE;
1362 	rtm->rtm_type = RTN_UNICAST;
1363 	rtm->rtm_flags = 0;
1364 
1365 	if (nla_put_labels(skb, RTA_DST, 1, &label))
1366 		goto nla_put_failure;
1367 	if (rt->rt_nhn == 1) {
1368 		const struct mpls_nh *nh = rt->rt_nh;
1369 
1370 		if (nh->nh_labels &&
1371 		    nla_put_labels(skb, RTA_NEWDST, nh->nh_labels,
1372 				   nh->nh_label))
1373 			goto nla_put_failure;
1374 		if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC &&
1375 		    nla_put_via(skb, nh->nh_via_table, mpls_nh_via(rt, nh),
1376 				nh->nh_via_alen))
1377 			goto nla_put_failure;
1378 		dev = rtnl_dereference(nh->nh_dev);
1379 		if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
1380 			goto nla_put_failure;
1381 		if (nh->nh_flags & RTNH_F_LINKDOWN)
1382 			rtm->rtm_flags |= RTNH_F_LINKDOWN;
1383 		if (nh->nh_flags & RTNH_F_DEAD)
1384 			rtm->rtm_flags |= RTNH_F_DEAD;
1385 	} else {
1386 		struct rtnexthop *rtnh;
1387 		struct nlattr *mp;
1388 		int dead = 0;
1389 		int linkdown = 0;
1390 
1391 		mp = nla_nest_start(skb, RTA_MULTIPATH);
1392 		if (!mp)
1393 			goto nla_put_failure;
1394 
1395 		for_nexthops(rt) {
1396 			rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1397 			if (!rtnh)
1398 				goto nla_put_failure;
1399 
1400 			dev = rtnl_dereference(nh->nh_dev);
1401 			if (dev)
1402 				rtnh->rtnh_ifindex = dev->ifindex;
1403 			if (nh->nh_flags & RTNH_F_LINKDOWN) {
1404 				rtnh->rtnh_flags |= RTNH_F_LINKDOWN;
1405 				linkdown++;
1406 			}
1407 			if (nh->nh_flags & RTNH_F_DEAD) {
1408 				rtnh->rtnh_flags |= RTNH_F_DEAD;
1409 				dead++;
1410 			}
1411 
1412 			if (nh->nh_labels && nla_put_labels(skb, RTA_NEWDST,
1413 							    nh->nh_labels,
1414 							    nh->nh_label))
1415 				goto nla_put_failure;
1416 			if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC &&
1417 			    nla_put_via(skb, nh->nh_via_table,
1418 					mpls_nh_via(rt, nh),
1419 					nh->nh_via_alen))
1420 				goto nla_put_failure;
1421 
1422 			/* length of rtnetlink header + attributes */
1423 			rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1424 		} endfor_nexthops(rt);
1425 
1426 		if (linkdown == rt->rt_nhn)
1427 			rtm->rtm_flags |= RTNH_F_LINKDOWN;
1428 		if (dead == rt->rt_nhn)
1429 			rtm->rtm_flags |= RTNH_F_DEAD;
1430 
1431 		nla_nest_end(skb, mp);
1432 	}
1433 
1434 	nlmsg_end(skb, nlh);
1435 	return 0;
1436 
1437 nla_put_failure:
1438 	nlmsg_cancel(skb, nlh);
1439 	return -EMSGSIZE;
1440 }
1441 
mpls_dump_routes(struct sk_buff * skb,struct netlink_callback * cb)1442 static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
1443 {
1444 	struct net *net = sock_net(skb->sk);
1445 	struct mpls_route __rcu **platform_label;
1446 	size_t platform_labels;
1447 	unsigned int index;
1448 
1449 	ASSERT_RTNL();
1450 
1451 	index = cb->args[0];
1452 	if (index < MPLS_LABEL_FIRST_UNRESERVED)
1453 		index = MPLS_LABEL_FIRST_UNRESERVED;
1454 
1455 	platform_label = rtnl_dereference(net->mpls.platform_label);
1456 	platform_labels = net->mpls.platform_labels;
1457 	for (; index < platform_labels; index++) {
1458 		struct mpls_route *rt;
1459 		rt = rtnl_dereference(platform_label[index]);
1460 		if (!rt)
1461 			continue;
1462 
1463 		if (mpls_dump_route(skb, NETLINK_CB(cb->skb).portid,
1464 				    cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1465 				    index, rt, NLM_F_MULTI) < 0)
1466 			break;
1467 	}
1468 	cb->args[0] = index;
1469 
1470 	return skb->len;
1471 }
1472 
lfib_nlmsg_size(struct mpls_route * rt)1473 static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
1474 {
1475 	size_t payload =
1476 		NLMSG_ALIGN(sizeof(struct rtmsg))
1477 		+ nla_total_size(4);			/* RTA_DST */
1478 
1479 	if (rt->rt_nhn == 1) {
1480 		struct mpls_nh *nh = rt->rt_nh;
1481 
1482 		if (nh->nh_dev)
1483 			payload += nla_total_size(4); /* RTA_OIF */
1484 		if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC) /* RTA_VIA */
1485 			payload += nla_total_size(2 + nh->nh_via_alen);
1486 		if (nh->nh_labels) /* RTA_NEWDST */
1487 			payload += nla_total_size(nh->nh_labels * 4);
1488 	} else {
1489 		/* each nexthop is packed in an attribute */
1490 		size_t nhsize = 0;
1491 
1492 		for_nexthops(rt) {
1493 			nhsize += nla_total_size(sizeof(struct rtnexthop));
1494 			/* RTA_VIA */
1495 			if (nh->nh_via_table != MPLS_NEIGH_TABLE_UNSPEC)
1496 				nhsize += nla_total_size(2 + nh->nh_via_alen);
1497 			if (nh->nh_labels)
1498 				nhsize += nla_total_size(nh->nh_labels * 4);
1499 		} endfor_nexthops(rt);
1500 		/* nested attribute */
1501 		payload += nla_total_size(nhsize);
1502 	}
1503 
1504 	return payload;
1505 }
1506 
rtmsg_lfib(int event,u32 label,struct mpls_route * rt,struct nlmsghdr * nlh,struct net * net,u32 portid,unsigned int nlm_flags)1507 static void rtmsg_lfib(int event, u32 label, struct mpls_route *rt,
1508 		       struct nlmsghdr *nlh, struct net *net, u32 portid,
1509 		       unsigned int nlm_flags)
1510 {
1511 	struct sk_buff *skb;
1512 	u32 seq = nlh ? nlh->nlmsg_seq : 0;
1513 	int err = -ENOBUFS;
1514 
1515 	skb = nlmsg_new(lfib_nlmsg_size(rt), GFP_KERNEL);
1516 	if (skb == NULL)
1517 		goto errout;
1518 
1519 	err = mpls_dump_route(skb, portid, seq, event, label, rt, nlm_flags);
1520 	if (err < 0) {
1521 		/* -EMSGSIZE implies BUG in lfib_nlmsg_size */
1522 		WARN_ON(err == -EMSGSIZE);
1523 		kfree_skb(skb);
1524 		goto errout;
1525 	}
1526 	rtnl_notify(skb, net, portid, RTNLGRP_MPLS_ROUTE, nlh, GFP_KERNEL);
1527 
1528 	return;
1529 errout:
1530 	if (err < 0)
1531 		rtnl_set_sk_err(net, RTNLGRP_MPLS_ROUTE, err);
1532 }
1533 
resize_platform_label_table(struct net * net,size_t limit)1534 static int resize_platform_label_table(struct net *net, size_t limit)
1535 {
1536 	size_t size = sizeof(struct mpls_route *) * limit;
1537 	size_t old_limit;
1538 	size_t cp_size;
1539 	struct mpls_route __rcu **labels = NULL, **old;
1540 	struct mpls_route *rt0 = NULL, *rt2 = NULL;
1541 	unsigned index;
1542 
1543 	if (size) {
1544 		labels = kzalloc(size, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
1545 		if (!labels)
1546 			labels = vzalloc(size);
1547 
1548 		if (!labels)
1549 			goto nolabels;
1550 	}
1551 
1552 	/* In case the predefined labels need to be populated */
1553 	if (limit > MPLS_LABEL_IPV4NULL) {
1554 		struct net_device *lo = net->loopback_dev;
1555 		rt0 = mpls_rt_alloc(1, lo->addr_len);
1556 		if (!rt0)
1557 			goto nort0;
1558 		RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo);
1559 		rt0->rt_protocol = RTPROT_KERNEL;
1560 		rt0->rt_payload_type = MPT_IPV4;
1561 		rt0->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
1562 		rt0->rt_nh->nh_via_alen = lo->addr_len;
1563 		memcpy(__mpls_nh_via(rt0, rt0->rt_nh), lo->dev_addr,
1564 		       lo->addr_len);
1565 	}
1566 	if (limit > MPLS_LABEL_IPV6NULL) {
1567 		struct net_device *lo = net->loopback_dev;
1568 		rt2 = mpls_rt_alloc(1, lo->addr_len);
1569 		if (!rt2)
1570 			goto nort2;
1571 		RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo);
1572 		rt2->rt_protocol = RTPROT_KERNEL;
1573 		rt2->rt_payload_type = MPT_IPV6;
1574 		rt2->rt_nh->nh_via_table = NEIGH_LINK_TABLE;
1575 		rt2->rt_nh->nh_via_alen = lo->addr_len;
1576 		memcpy(__mpls_nh_via(rt2, rt2->rt_nh), lo->dev_addr,
1577 		       lo->addr_len);
1578 	}
1579 
1580 	rtnl_lock();
1581 	/* Remember the original table */
1582 	old = rtnl_dereference(net->mpls.platform_label);
1583 	old_limit = net->mpls.platform_labels;
1584 
1585 	/* Free any labels beyond the new table */
1586 	for (index = limit; index < old_limit; index++)
1587 		mpls_route_update(net, index, NULL, NULL);
1588 
1589 	/* Copy over the old labels */
1590 	cp_size = size;
1591 	if (old_limit < limit)
1592 		cp_size = old_limit * sizeof(struct mpls_route *);
1593 
1594 	memcpy(labels, old, cp_size);
1595 
1596 	/* If needed set the predefined labels */
1597 	if ((old_limit <= MPLS_LABEL_IPV6NULL) &&
1598 	    (limit > MPLS_LABEL_IPV6NULL)) {
1599 		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV6NULL], rt2);
1600 		rt2 = NULL;
1601 	}
1602 
1603 	if ((old_limit <= MPLS_LABEL_IPV4NULL) &&
1604 	    (limit > MPLS_LABEL_IPV4NULL)) {
1605 		RCU_INIT_POINTER(labels[MPLS_LABEL_IPV4NULL], rt0);
1606 		rt0 = NULL;
1607 	}
1608 
1609 	/* Update the global pointers */
1610 	net->mpls.platform_labels = limit;
1611 	rcu_assign_pointer(net->mpls.platform_label, labels);
1612 
1613 	rtnl_unlock();
1614 
1615 	mpls_rt_free(rt2);
1616 	mpls_rt_free(rt0);
1617 
1618 	if (old) {
1619 		synchronize_rcu();
1620 		kvfree(old);
1621 	}
1622 	return 0;
1623 
1624 nort2:
1625 	mpls_rt_free(rt0);
1626 nort0:
1627 	kvfree(labels);
1628 nolabels:
1629 	return -ENOMEM;
1630 }
1631 
mpls_platform_labels(struct ctl_table * table,int write,void __user * buffer,size_t * lenp,loff_t * ppos)1632 static int mpls_platform_labels(struct ctl_table *table, int write,
1633 				void __user *buffer, size_t *lenp, loff_t *ppos)
1634 {
1635 	struct net *net = table->data;
1636 	int platform_labels = net->mpls.platform_labels;
1637 	int ret;
1638 	struct ctl_table tmp = {
1639 		.procname	= table->procname,
1640 		.data		= &platform_labels,
1641 		.maxlen		= sizeof(int),
1642 		.mode		= table->mode,
1643 		.extra1		= &zero,
1644 		.extra2		= &label_limit,
1645 	};
1646 
1647 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
1648 
1649 	if (write && ret == 0)
1650 		ret = resize_platform_label_table(net, platform_labels);
1651 
1652 	return ret;
1653 }
1654 
1655 static const struct ctl_table mpls_table[] = {
1656 	{
1657 		.procname	= "platform_labels",
1658 		.data		= NULL,
1659 		.maxlen		= sizeof(int),
1660 		.mode		= 0644,
1661 		.proc_handler	= mpls_platform_labels,
1662 	},
1663 	{ }
1664 };
1665 
mpls_net_init(struct net * net)1666 static int mpls_net_init(struct net *net)
1667 {
1668 	struct ctl_table *table;
1669 
1670 	net->mpls.platform_labels = 0;
1671 	net->mpls.platform_label = NULL;
1672 
1673 	table = kmemdup(mpls_table, sizeof(mpls_table), GFP_KERNEL);
1674 	if (table == NULL)
1675 		return -ENOMEM;
1676 
1677 	table[0].data = net;
1678 	net->mpls.ctl = register_net_sysctl(net, "net/mpls", table);
1679 	if (net->mpls.ctl == NULL) {
1680 		kfree(table);
1681 		return -ENOMEM;
1682 	}
1683 
1684 	return 0;
1685 }
1686 
mpls_net_exit(struct net * net)1687 static void mpls_net_exit(struct net *net)
1688 {
1689 	struct mpls_route __rcu **platform_label;
1690 	size_t platform_labels;
1691 	struct ctl_table *table;
1692 	unsigned int index;
1693 
1694 	table = net->mpls.ctl->ctl_table_arg;
1695 	unregister_net_sysctl_table(net->mpls.ctl);
1696 	kfree(table);
1697 
1698 	/* An rcu grace period has passed since there was a device in
1699 	 * the network namespace (and thus the last in flight packet)
1700 	 * left this network namespace.  This is because
1701 	 * unregister_netdevice_many and netdev_run_todo has completed
1702 	 * for each network device that was in this network namespace.
1703 	 *
1704 	 * As such no additional rcu synchronization is necessary when
1705 	 * freeing the platform_label table.
1706 	 */
1707 	rtnl_lock();
1708 	platform_label = rtnl_dereference(net->mpls.platform_label);
1709 	platform_labels = net->mpls.platform_labels;
1710 	for (index = 0; index < platform_labels; index++) {
1711 		struct mpls_route *rt = rtnl_dereference(platform_label[index]);
1712 		RCU_INIT_POINTER(platform_label[index], NULL);
1713 		mpls_notify_route(net, index, rt, NULL, NULL);
1714 		mpls_rt_free(rt);
1715 	}
1716 	rtnl_unlock();
1717 
1718 	kvfree(platform_label);
1719 }
1720 
1721 static struct pernet_operations mpls_net_ops = {
1722 	.init = mpls_net_init,
1723 	.exit = mpls_net_exit,
1724 };
1725 
mpls_init(void)1726 static int __init mpls_init(void)
1727 {
1728 	int err;
1729 
1730 	BUILD_BUG_ON(sizeof(struct mpls_shim_hdr) != 4);
1731 
1732 	err = register_pernet_subsys(&mpls_net_ops);
1733 	if (err)
1734 		goto out;
1735 
1736 	err = register_netdevice_notifier(&mpls_dev_notifier);
1737 	if (err)
1738 		goto out_unregister_pernet;
1739 
1740 	dev_add_pack(&mpls_packet_type);
1741 
1742 	rtnl_register(PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, NULL);
1743 	rtnl_register(PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, NULL);
1744 	rtnl_register(PF_MPLS, RTM_GETROUTE, NULL, mpls_dump_routes, NULL);
1745 	err = 0;
1746 out:
1747 	return err;
1748 
1749 out_unregister_pernet:
1750 	unregister_pernet_subsys(&mpls_net_ops);
1751 	goto out;
1752 }
1753 module_init(mpls_init);
1754 
mpls_exit(void)1755 static void __exit mpls_exit(void)
1756 {
1757 	rtnl_unregister_all(PF_MPLS);
1758 	dev_remove_pack(&mpls_packet_type);
1759 	unregister_netdevice_notifier(&mpls_dev_notifier);
1760 	unregister_pernet_subsys(&mpls_net_ops);
1761 }
1762 module_exit(mpls_exit);
1763 
1764 MODULE_DESCRIPTION("MultiProtocol Label Switching");
1765 MODULE_LICENSE("GPL v2");
1766 MODULE_ALIAS_NETPROTO(PF_MPLS);
1767