xref: /openbmc/linux/net/ipv6/ndisc.c (revision b737eecd)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	Neighbour Discovery for IPv6
4  *	Linux INET6 implementation
5  *
6  *	Authors:
7  *	Pedro Roque		<roque@di.fc.ul.pt>
8  *	Mike Shaver		<shaver@ingenia.com>
9  */
10 
11 /*
12  *	Changes:
13  *
14  *	Alexey I. Froloff		:	RFC6106 (DNSSL) support
15  *	Pierre Ynard			:	export userland ND options
16  *						through netlink (RDNSS support)
17  *	Lars Fenneberg			:	fixed MTU setting on receipt
18  *						of an RA.
19  *	Janos Farkas			:	kmalloc failure checks
20  *	Alexey Kuznetsov		:	state machine reworked
21  *						and moved to net/core.
22  *	Pekka Savola			:	RFC2461 validation
23  *	YOSHIFUJI Hideaki @USAGI	:	Verify ND options properly
24  */
25 
26 #define pr_fmt(fmt) "ICMPv6: " fmt
27 
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/types.h>
31 #include <linux/socket.h>
32 #include <linux/sockios.h>
33 #include <linux/sched.h>
34 #include <linux/net.h>
35 #include <linux/in6.h>
36 #include <linux/route.h>
37 #include <linux/init.h>
38 #include <linux/rcupdate.h>
39 #include <linux/slab.h>
40 #ifdef CONFIG_SYSCTL
41 #include <linux/sysctl.h>
42 #endif
43 
44 #include <linux/if_addr.h>
45 #include <linux/if_ether.h>
46 #include <linux/if_arp.h>
47 #include <linux/ipv6.h>
48 #include <linux/icmpv6.h>
49 #include <linux/jhash.h>
50 
51 #include <net/sock.h>
52 #include <net/snmp.h>
53 
54 #include <net/ipv6.h>
55 #include <net/protocol.h>
56 #include <net/ndisc.h>
57 #include <net/ip6_route.h>
58 #include <net/addrconf.h>
59 #include <net/icmp.h>
60 
61 #include <net/netlink.h>
62 #include <linux/rtnetlink.h>
63 
64 #include <net/flow.h>
65 #include <net/ip6_checksum.h>
66 #include <net/inet_common.h>
67 #include <linux/proc_fs.h>
68 
69 #include <linux/netfilter.h>
70 #include <linux/netfilter_ipv6.h>
71 
72 static u32 ndisc_hash(const void *pkey,
73 		      const struct net_device *dev,
74 		      __u32 *hash_rnd);
75 static bool ndisc_key_eq(const struct neighbour *neigh, const void *pkey);
76 static bool ndisc_allow_add(const struct net_device *dev,
77 			    struct netlink_ext_ack *extack);
78 static int ndisc_constructor(struct neighbour *neigh);
79 static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb);
80 static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb);
81 static int pndisc_constructor(struct pneigh_entry *n);
82 static void pndisc_destructor(struct pneigh_entry *n);
83 static void pndisc_redo(struct sk_buff *skb);
84 static int ndisc_is_multicast(const void *pkey);
85 
86 static const struct neigh_ops ndisc_generic_ops = {
87 	.family =		AF_INET6,
88 	.solicit =		ndisc_solicit,
89 	.error_report =		ndisc_error_report,
90 	.output =		neigh_resolve_output,
91 	.connected_output =	neigh_connected_output,
92 };
93 
94 static const struct neigh_ops ndisc_hh_ops = {
95 	.family =		AF_INET6,
96 	.solicit =		ndisc_solicit,
97 	.error_report =		ndisc_error_report,
98 	.output =		neigh_resolve_output,
99 	.connected_output =	neigh_resolve_output,
100 };
101 
102 
103 static const struct neigh_ops ndisc_direct_ops = {
104 	.family =		AF_INET6,
105 	.output =		neigh_direct_output,
106 	.connected_output =	neigh_direct_output,
107 };
108 
109 struct neigh_table nd_tbl = {
110 	.family =	AF_INET6,
111 	.key_len =	sizeof(struct in6_addr),
112 	.protocol =	cpu_to_be16(ETH_P_IPV6),
113 	.hash =		ndisc_hash,
114 	.key_eq =	ndisc_key_eq,
115 	.constructor =	ndisc_constructor,
116 	.pconstructor =	pndisc_constructor,
117 	.pdestructor =	pndisc_destructor,
118 	.proxy_redo =	pndisc_redo,
119 	.is_multicast =	ndisc_is_multicast,
120 	.allow_add  =   ndisc_allow_add,
121 	.id =		"ndisc_cache",
122 	.parms = {
123 		.tbl			= &nd_tbl,
124 		.reachable_time		= ND_REACHABLE_TIME,
125 		.data = {
126 			[NEIGH_VAR_MCAST_PROBES] = 3,
127 			[NEIGH_VAR_UCAST_PROBES] = 3,
128 			[NEIGH_VAR_RETRANS_TIME] = ND_RETRANS_TIMER,
129 			[NEIGH_VAR_BASE_REACHABLE_TIME] = ND_REACHABLE_TIME,
130 			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
131 			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
132 			[NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
133 			[NEIGH_VAR_PROXY_QLEN] = 64,
134 			[NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
135 			[NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
136 		},
137 	},
138 	.gc_interval =	  30 * HZ,
139 	.gc_thresh1 =	 128,
140 	.gc_thresh2 =	 512,
141 	.gc_thresh3 =	1024,
142 };
143 EXPORT_SYMBOL_GPL(nd_tbl);
144 
145 void __ndisc_fill_addr_option(struct sk_buff *skb, int type, void *data,
146 			      int data_len, int pad)
147 {
148 	int space = __ndisc_opt_addr_space(data_len, pad);
149 	u8 *opt = skb_put(skb, space);
150 
151 	opt[0] = type;
152 	opt[1] = space>>3;
153 
154 	memset(opt + 2, 0, pad);
155 	opt   += pad;
156 	space -= pad;
157 
158 	memcpy(opt+2, data, data_len);
159 	data_len += 2;
160 	opt += data_len;
161 	space -= data_len;
162 	if (space > 0)
163 		memset(opt, 0, space);
164 }
165 EXPORT_SYMBOL_GPL(__ndisc_fill_addr_option);
166 
167 static inline void ndisc_fill_addr_option(struct sk_buff *skb, int type,
168 					  void *data, u8 icmp6_type)
169 {
170 	__ndisc_fill_addr_option(skb, type, data, skb->dev->addr_len,
171 				 ndisc_addr_option_pad(skb->dev->type));
172 	ndisc_ops_fill_addr_option(skb->dev, skb, icmp6_type);
173 }
174 
175 static inline void ndisc_fill_redirect_addr_option(struct sk_buff *skb,
176 						   void *ha,
177 						   const u8 *ops_data)
178 {
179 	ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR, ha, NDISC_REDIRECT);
180 	ndisc_ops_fill_redirect_addr_option(skb->dev, skb, ops_data);
181 }
182 
183 static struct nd_opt_hdr *ndisc_next_option(struct nd_opt_hdr *cur,
184 					    struct nd_opt_hdr *end)
185 {
186 	int type;
187 	if (!cur || !end || cur >= end)
188 		return NULL;
189 	type = cur->nd_opt_type;
190 	do {
191 		cur = ((void *)cur) + (cur->nd_opt_len << 3);
192 	} while (cur < end && cur->nd_opt_type != type);
193 	return cur <= end && cur->nd_opt_type == type ? cur : NULL;
194 }
195 
196 static inline int ndisc_is_useropt(const struct net_device *dev,
197 				   struct nd_opt_hdr *opt)
198 {
199 	return opt->nd_opt_type == ND_OPT_RDNSS ||
200 		opt->nd_opt_type == ND_OPT_DNSSL ||
201 		opt->nd_opt_type == ND_OPT_CAPTIVE_PORTAL ||
202 		opt->nd_opt_type == ND_OPT_PREF64 ||
203 		ndisc_ops_is_useropt(dev, opt->nd_opt_type);
204 }
205 
206 static struct nd_opt_hdr *ndisc_next_useropt(const struct net_device *dev,
207 					     struct nd_opt_hdr *cur,
208 					     struct nd_opt_hdr *end)
209 {
210 	if (!cur || !end || cur >= end)
211 		return NULL;
212 	do {
213 		cur = ((void *)cur) + (cur->nd_opt_len << 3);
214 	} while (cur < end && !ndisc_is_useropt(dev, cur));
215 	return cur <= end && ndisc_is_useropt(dev, cur) ? cur : NULL;
216 }
217 
218 struct ndisc_options *ndisc_parse_options(const struct net_device *dev,
219 					  u8 *opt, int opt_len,
220 					  struct ndisc_options *ndopts)
221 {
222 	struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt;
223 
224 	if (!nd_opt || opt_len < 0 || !ndopts)
225 		return NULL;
226 	memset(ndopts, 0, sizeof(*ndopts));
227 	while (opt_len) {
228 		int l;
229 		if (opt_len < sizeof(struct nd_opt_hdr))
230 			return NULL;
231 		l = nd_opt->nd_opt_len << 3;
232 		if (opt_len < l || l == 0)
233 			return NULL;
234 		if (ndisc_ops_parse_options(dev, nd_opt, ndopts))
235 			goto next_opt;
236 		switch (nd_opt->nd_opt_type) {
237 		case ND_OPT_SOURCE_LL_ADDR:
238 		case ND_OPT_TARGET_LL_ADDR:
239 		case ND_OPT_MTU:
240 		case ND_OPT_NONCE:
241 		case ND_OPT_REDIRECT_HDR:
242 			if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
243 				ND_PRINTK(2, warn,
244 					  "%s: duplicated ND6 option found: type=%d\n",
245 					  __func__, nd_opt->nd_opt_type);
246 			} else {
247 				ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
248 			}
249 			break;
250 		case ND_OPT_PREFIX_INFO:
251 			ndopts->nd_opts_pi_end = nd_opt;
252 			if (!ndopts->nd_opt_array[nd_opt->nd_opt_type])
253 				ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
254 			break;
255 #ifdef CONFIG_IPV6_ROUTE_INFO
256 		case ND_OPT_ROUTE_INFO:
257 			ndopts->nd_opts_ri_end = nd_opt;
258 			if (!ndopts->nd_opts_ri)
259 				ndopts->nd_opts_ri = nd_opt;
260 			break;
261 #endif
262 		default:
263 			if (ndisc_is_useropt(dev, nd_opt)) {
264 				ndopts->nd_useropts_end = nd_opt;
265 				if (!ndopts->nd_useropts)
266 					ndopts->nd_useropts = nd_opt;
267 			} else {
268 				/*
269 				 * Unknown options must be silently ignored,
270 				 * to accommodate future extension to the
271 				 * protocol.
272 				 */
273 				ND_PRINTK(2, notice,
274 					  "%s: ignored unsupported option; type=%d, len=%d\n",
275 					  __func__,
276 					  nd_opt->nd_opt_type,
277 					  nd_opt->nd_opt_len);
278 			}
279 		}
280 next_opt:
281 		opt_len -= l;
282 		nd_opt = ((void *)nd_opt) + l;
283 	}
284 	return ndopts;
285 }
286 
287 int ndisc_mc_map(const struct in6_addr *addr, char *buf, struct net_device *dev, int dir)
288 {
289 	switch (dev->type) {
290 	case ARPHRD_ETHER:
291 	case ARPHRD_IEEE802:	/* Not sure. Check it later. --ANK */
292 	case ARPHRD_FDDI:
293 		ipv6_eth_mc_map(addr, buf);
294 		return 0;
295 	case ARPHRD_ARCNET:
296 		ipv6_arcnet_mc_map(addr, buf);
297 		return 0;
298 	case ARPHRD_INFINIBAND:
299 		ipv6_ib_mc_map(addr, dev->broadcast, buf);
300 		return 0;
301 	case ARPHRD_IPGRE:
302 		return ipv6_ipgre_mc_map(addr, dev->broadcast, buf);
303 	default:
304 		if (dir) {
305 			memcpy(buf, dev->broadcast, dev->addr_len);
306 			return 0;
307 		}
308 	}
309 	return -EINVAL;
310 }
311 EXPORT_SYMBOL(ndisc_mc_map);
312 
313 static u32 ndisc_hash(const void *pkey,
314 		      const struct net_device *dev,
315 		      __u32 *hash_rnd)
316 {
317 	return ndisc_hashfn(pkey, dev, hash_rnd);
318 }
319 
320 static bool ndisc_key_eq(const struct neighbour *n, const void *pkey)
321 {
322 	return neigh_key_eq128(n, pkey);
323 }
324 
325 static int ndisc_constructor(struct neighbour *neigh)
326 {
327 	struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key;
328 	struct net_device *dev = neigh->dev;
329 	struct inet6_dev *in6_dev;
330 	struct neigh_parms *parms;
331 	bool is_multicast = ipv6_addr_is_multicast(addr);
332 
333 	in6_dev = in6_dev_get(dev);
334 	if (!in6_dev) {
335 		return -EINVAL;
336 	}
337 
338 	parms = in6_dev->nd_parms;
339 	__neigh_parms_put(neigh->parms);
340 	neigh->parms = neigh_parms_clone(parms);
341 
342 	neigh->type = is_multicast ? RTN_MULTICAST : RTN_UNICAST;
343 	if (!dev->header_ops) {
344 		neigh->nud_state = NUD_NOARP;
345 		neigh->ops = &ndisc_direct_ops;
346 		neigh->output = neigh_direct_output;
347 	} else {
348 		if (is_multicast) {
349 			neigh->nud_state = NUD_NOARP;
350 			ndisc_mc_map(addr, neigh->ha, dev, 1);
351 		} else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
352 			neigh->nud_state = NUD_NOARP;
353 			memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
354 			if (dev->flags&IFF_LOOPBACK)
355 				neigh->type = RTN_LOCAL;
356 		} else if (dev->flags&IFF_POINTOPOINT) {
357 			neigh->nud_state = NUD_NOARP;
358 			memcpy(neigh->ha, dev->broadcast, dev->addr_len);
359 		}
360 		if (dev->header_ops->cache)
361 			neigh->ops = &ndisc_hh_ops;
362 		else
363 			neigh->ops = &ndisc_generic_ops;
364 		if (neigh->nud_state&NUD_VALID)
365 			neigh->output = neigh->ops->connected_output;
366 		else
367 			neigh->output = neigh->ops->output;
368 	}
369 	in6_dev_put(in6_dev);
370 	return 0;
371 }
372 
373 static int pndisc_constructor(struct pneigh_entry *n)
374 {
375 	struct in6_addr *addr = (struct in6_addr *)&n->key;
376 	struct in6_addr maddr;
377 	struct net_device *dev = n->dev;
378 
379 	if (!dev || !__in6_dev_get(dev))
380 		return -EINVAL;
381 	addrconf_addr_solict_mult(addr, &maddr);
382 	ipv6_dev_mc_inc(dev, &maddr);
383 	return 0;
384 }
385 
386 static void pndisc_destructor(struct pneigh_entry *n)
387 {
388 	struct in6_addr *addr = (struct in6_addr *)&n->key;
389 	struct in6_addr maddr;
390 	struct net_device *dev = n->dev;
391 
392 	if (!dev || !__in6_dev_get(dev))
393 		return;
394 	addrconf_addr_solict_mult(addr, &maddr);
395 	ipv6_dev_mc_dec(dev, &maddr);
396 }
397 
398 /* called with rtnl held */
399 static bool ndisc_allow_add(const struct net_device *dev,
400 			    struct netlink_ext_ack *extack)
401 {
402 	struct inet6_dev *idev = __in6_dev_get(dev);
403 
404 	if (!idev || idev->cnf.disable_ipv6) {
405 		NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
406 		return false;
407 	}
408 
409 	return true;
410 }
411 
412 static struct sk_buff *ndisc_alloc_skb(struct net_device *dev,
413 				       int len)
414 {
415 	int hlen = LL_RESERVED_SPACE(dev);
416 	int tlen = dev->needed_tailroom;
417 	struct sock *sk = dev_net(dev)->ipv6.ndisc_sk;
418 	struct sk_buff *skb;
419 
420 	skb = alloc_skb(hlen + sizeof(struct ipv6hdr) + len + tlen, GFP_ATOMIC);
421 	if (!skb) {
422 		ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb\n",
423 			  __func__);
424 		return NULL;
425 	}
426 
427 	skb->protocol = htons(ETH_P_IPV6);
428 	skb->dev = dev;
429 
430 	skb_reserve(skb, hlen + sizeof(struct ipv6hdr));
431 	skb_reset_transport_header(skb);
432 
433 	/* Manually assign socket ownership as we avoid calling
434 	 * sock_alloc_send_pskb() to bypass wmem buffer limits
435 	 */
436 	skb_set_owner_w(skb, sk);
437 
438 	return skb;
439 }
440 
441 static void ip6_nd_hdr(struct sk_buff *skb,
442 		       const struct in6_addr *saddr,
443 		       const struct in6_addr *daddr,
444 		       int hop_limit, int len)
445 {
446 	struct ipv6hdr *hdr;
447 	struct inet6_dev *idev;
448 	unsigned tclass;
449 
450 	rcu_read_lock();
451 	idev = __in6_dev_get(skb->dev);
452 	tclass = idev ? idev->cnf.ndisc_tclass : 0;
453 	rcu_read_unlock();
454 
455 	skb_push(skb, sizeof(*hdr));
456 	skb_reset_network_header(skb);
457 	hdr = ipv6_hdr(skb);
458 
459 	ip6_flow_hdr(hdr, tclass, 0);
460 
461 	hdr->payload_len = htons(len);
462 	hdr->nexthdr = IPPROTO_ICMPV6;
463 	hdr->hop_limit = hop_limit;
464 
465 	hdr->saddr = *saddr;
466 	hdr->daddr = *daddr;
467 }
468 
469 static void ndisc_send_skb(struct sk_buff *skb,
470 			   const struct in6_addr *daddr,
471 			   const struct in6_addr *saddr)
472 {
473 	struct dst_entry *dst = skb_dst(skb);
474 	struct net *net = dev_net(skb->dev);
475 	struct sock *sk = net->ipv6.ndisc_sk;
476 	struct inet6_dev *idev;
477 	int err;
478 	struct icmp6hdr *icmp6h = icmp6_hdr(skb);
479 	u8 type;
480 
481 	type = icmp6h->icmp6_type;
482 
483 	if (!dst) {
484 		struct flowi6 fl6;
485 		int oif = skb->dev->ifindex;
486 
487 		icmpv6_flow_init(sk, &fl6, type, saddr, daddr, oif);
488 		dst = icmp6_dst_alloc(skb->dev, &fl6);
489 		if (IS_ERR(dst)) {
490 			kfree_skb(skb);
491 			return;
492 		}
493 
494 		skb_dst_set(skb, dst);
495 	}
496 
497 	icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, skb->len,
498 					      IPPROTO_ICMPV6,
499 					      csum_partial(icmp6h,
500 							   skb->len, 0));
501 
502 	ip6_nd_hdr(skb, saddr, daddr, inet6_sk(sk)->hop_limit, skb->len);
503 
504 	rcu_read_lock();
505 	idev = __in6_dev_get(dst->dev);
506 	IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
507 
508 	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
509 		      net, sk, skb, NULL, dst->dev,
510 		      dst_output);
511 	if (!err) {
512 		ICMP6MSGOUT_INC_STATS(net, idev, type);
513 		ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
514 	}
515 
516 	rcu_read_unlock();
517 }
518 
519 void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
520 		   const struct in6_addr *solicited_addr,
521 		   bool router, bool solicited, bool override, bool inc_opt)
522 {
523 	struct sk_buff *skb;
524 	struct in6_addr tmpaddr;
525 	struct inet6_ifaddr *ifp;
526 	const struct in6_addr *src_addr;
527 	struct nd_msg *msg;
528 	int optlen = 0;
529 
530 	/* for anycast or proxy, solicited_addr != src_addr */
531 	ifp = ipv6_get_ifaddr(dev_net(dev), solicited_addr, dev, 1);
532 	if (ifp) {
533 		src_addr = solicited_addr;
534 		if (ifp->flags & IFA_F_OPTIMISTIC)
535 			override = false;
536 		inc_opt |= ifp->idev->cnf.force_tllao;
537 		in6_ifa_put(ifp);
538 	} else {
539 		if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
540 				       inet6_sk(dev_net(dev)->ipv6.ndisc_sk)->srcprefs,
541 				       &tmpaddr))
542 			return;
543 		src_addr = &tmpaddr;
544 	}
545 
546 	if (!dev->addr_len)
547 		inc_opt = false;
548 	if (inc_opt)
549 		optlen += ndisc_opt_addr_space(dev,
550 					       NDISC_NEIGHBOUR_ADVERTISEMENT);
551 
552 	skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
553 	if (!skb)
554 		return;
555 
556 	msg = skb_put(skb, sizeof(*msg));
557 	*msg = (struct nd_msg) {
558 		.icmph = {
559 			.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT,
560 			.icmp6_router = router,
561 			.icmp6_solicited = solicited,
562 			.icmp6_override = override,
563 		},
564 		.target = *solicited_addr,
565 	};
566 
567 	if (inc_opt)
568 		ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
569 				       dev->dev_addr,
570 				       NDISC_NEIGHBOUR_ADVERTISEMENT);
571 
572 	ndisc_send_skb(skb, daddr, src_addr);
573 }
574 
575 static void ndisc_send_unsol_na(struct net_device *dev)
576 {
577 	struct inet6_dev *idev;
578 	struct inet6_ifaddr *ifa;
579 
580 	idev = in6_dev_get(dev);
581 	if (!idev)
582 		return;
583 
584 	read_lock_bh(&idev->lock);
585 	list_for_each_entry(ifa, &idev->addr_list, if_list) {
586 		/* skip tentative addresses until dad completes */
587 		if (ifa->flags & IFA_F_TENTATIVE &&
588 		    !(ifa->flags & IFA_F_OPTIMISTIC))
589 			continue;
590 
591 		ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifa->addr,
592 			      /*router=*/ !!idev->cnf.forwarding,
593 			      /*solicited=*/ false, /*override=*/ true,
594 			      /*inc_opt=*/ true);
595 	}
596 	read_unlock_bh(&idev->lock);
597 
598 	in6_dev_put(idev);
599 }
600 
601 void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit,
602 		   const struct in6_addr *daddr, const struct in6_addr *saddr,
603 		   u64 nonce)
604 {
605 	struct sk_buff *skb;
606 	struct in6_addr addr_buf;
607 	int inc_opt = dev->addr_len;
608 	int optlen = 0;
609 	struct nd_msg *msg;
610 
611 	if (!saddr) {
612 		if (ipv6_get_lladdr(dev, &addr_buf,
613 				   (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)))
614 			return;
615 		saddr = &addr_buf;
616 	}
617 
618 	if (ipv6_addr_any(saddr))
619 		inc_opt = false;
620 	if (inc_opt)
621 		optlen += ndisc_opt_addr_space(dev,
622 					       NDISC_NEIGHBOUR_SOLICITATION);
623 	if (nonce != 0)
624 		optlen += 8;
625 
626 	skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
627 	if (!skb)
628 		return;
629 
630 	msg = skb_put(skb, sizeof(*msg));
631 	*msg = (struct nd_msg) {
632 		.icmph = {
633 			.icmp6_type = NDISC_NEIGHBOUR_SOLICITATION,
634 		},
635 		.target = *solicit,
636 	};
637 
638 	if (inc_opt)
639 		ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
640 				       dev->dev_addr,
641 				       NDISC_NEIGHBOUR_SOLICITATION);
642 	if (nonce != 0) {
643 		u8 *opt = skb_put(skb, 8);
644 
645 		opt[0] = ND_OPT_NONCE;
646 		opt[1] = 8 >> 3;
647 		memcpy(opt + 2, &nonce, 6);
648 	}
649 
650 	ndisc_send_skb(skb, daddr, saddr);
651 }
652 
653 void ndisc_send_rs(struct net_device *dev, const struct in6_addr *saddr,
654 		   const struct in6_addr *daddr)
655 {
656 	struct sk_buff *skb;
657 	struct rs_msg *msg;
658 	int send_sllao = dev->addr_len;
659 	int optlen = 0;
660 
661 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
662 	/*
663 	 * According to section 2.2 of RFC 4429, we must not
664 	 * send router solicitations with a sllao from
665 	 * optimistic addresses, but we may send the solicitation
666 	 * if we don't include the sllao.  So here we check
667 	 * if our address is optimistic, and if so, we
668 	 * suppress the inclusion of the sllao.
669 	 */
670 	if (send_sllao) {
671 		struct inet6_ifaddr *ifp = ipv6_get_ifaddr(dev_net(dev), saddr,
672 							   dev, 1);
673 		if (ifp) {
674 			if (ifp->flags & IFA_F_OPTIMISTIC)  {
675 				send_sllao = 0;
676 			}
677 			in6_ifa_put(ifp);
678 		} else {
679 			send_sllao = 0;
680 		}
681 	}
682 #endif
683 	if (send_sllao)
684 		optlen += ndisc_opt_addr_space(dev, NDISC_ROUTER_SOLICITATION);
685 
686 	skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
687 	if (!skb)
688 		return;
689 
690 	msg = skb_put(skb, sizeof(*msg));
691 	*msg = (struct rs_msg) {
692 		.icmph = {
693 			.icmp6_type = NDISC_ROUTER_SOLICITATION,
694 		},
695 	};
696 
697 	if (send_sllao)
698 		ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
699 				       dev->dev_addr,
700 				       NDISC_ROUTER_SOLICITATION);
701 
702 	ndisc_send_skb(skb, daddr, saddr);
703 }
704 
705 
706 static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb)
707 {
708 	/*
709 	 *	"The sender MUST return an ICMP
710 	 *	 destination unreachable"
711 	 */
712 	dst_link_failure(skb);
713 	kfree_skb(skb);
714 }
715 
716 /* Called with locked neigh: either read or both */
717 
718 static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
719 {
720 	struct in6_addr *saddr = NULL;
721 	struct in6_addr mcaddr;
722 	struct net_device *dev = neigh->dev;
723 	struct in6_addr *target = (struct in6_addr *)&neigh->primary_key;
724 	int probes = atomic_read(&neigh->probes);
725 
726 	if (skb && ipv6_chk_addr_and_flags(dev_net(dev), &ipv6_hdr(skb)->saddr,
727 					   dev, false, 1,
728 					   IFA_F_TENTATIVE|IFA_F_OPTIMISTIC))
729 		saddr = &ipv6_hdr(skb)->saddr;
730 	probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
731 	if (probes < 0) {
732 		if (!(neigh->nud_state & NUD_VALID)) {
733 			ND_PRINTK(1, dbg,
734 				  "%s: trying to ucast probe in NUD_INVALID: %pI6\n",
735 				  __func__, target);
736 		}
737 		ndisc_send_ns(dev, target, target, saddr, 0);
738 	} else if ((probes -= NEIGH_VAR(neigh->parms, APP_PROBES)) < 0) {
739 		neigh_app_ns(neigh);
740 	} else {
741 		addrconf_addr_solict_mult(target, &mcaddr);
742 		ndisc_send_ns(dev, target, &mcaddr, saddr, 0);
743 	}
744 }
745 
746 static int pndisc_is_router(const void *pkey,
747 			    struct net_device *dev)
748 {
749 	struct pneigh_entry *n;
750 	int ret = -1;
751 
752 	read_lock_bh(&nd_tbl.lock);
753 	n = __pneigh_lookup(&nd_tbl, dev_net(dev), pkey, dev);
754 	if (n)
755 		ret = !!(n->flags & NTF_ROUTER);
756 	read_unlock_bh(&nd_tbl.lock);
757 
758 	return ret;
759 }
760 
761 void ndisc_update(const struct net_device *dev, struct neighbour *neigh,
762 		  const u8 *lladdr, u8 new, u32 flags, u8 icmp6_type,
763 		  struct ndisc_options *ndopts)
764 {
765 	neigh_update(neigh, lladdr, new, flags, 0);
766 	/* report ndisc ops about neighbour update */
767 	ndisc_ops_update(dev, neigh, flags, icmp6_type, ndopts);
768 }
769 
770 static void ndisc_recv_ns(struct sk_buff *skb)
771 {
772 	struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
773 	const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
774 	const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
775 	u8 *lladdr = NULL;
776 	u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
777 				    offsetof(struct nd_msg, opt));
778 	struct ndisc_options ndopts;
779 	struct net_device *dev = skb->dev;
780 	struct inet6_ifaddr *ifp;
781 	struct inet6_dev *idev = NULL;
782 	struct neighbour *neigh;
783 	int dad = ipv6_addr_any(saddr);
784 	bool inc;
785 	int is_router = -1;
786 	u64 nonce = 0;
787 
788 	if (skb->len < sizeof(struct nd_msg)) {
789 		ND_PRINTK(2, warn, "NS: packet too short\n");
790 		return;
791 	}
792 
793 	if (ipv6_addr_is_multicast(&msg->target)) {
794 		ND_PRINTK(2, warn, "NS: multicast target address\n");
795 		return;
796 	}
797 
798 	/*
799 	 * RFC2461 7.1.1:
800 	 * DAD has to be destined for solicited node multicast address.
801 	 */
802 	if (dad && !ipv6_addr_is_solict_mult(daddr)) {
803 		ND_PRINTK(2, warn, "NS: bad DAD packet (wrong destination)\n");
804 		return;
805 	}
806 
807 	if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
808 		ND_PRINTK(2, warn, "NS: invalid ND options\n");
809 		return;
810 	}
811 
812 	if (ndopts.nd_opts_src_lladdr) {
813 		lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev);
814 		if (!lladdr) {
815 			ND_PRINTK(2, warn,
816 				  "NS: invalid link-layer address length\n");
817 			return;
818 		}
819 
820 		/* RFC2461 7.1.1:
821 		 *	If the IP source address is the unspecified address,
822 		 *	there MUST NOT be source link-layer address option
823 		 *	in the message.
824 		 */
825 		if (dad) {
826 			ND_PRINTK(2, warn,
827 				  "NS: bad DAD packet (link-layer address option)\n");
828 			return;
829 		}
830 	}
831 	if (ndopts.nd_opts_nonce && ndopts.nd_opts_nonce->nd_opt_len == 1)
832 		memcpy(&nonce, (u8 *)(ndopts.nd_opts_nonce + 1), 6);
833 
834 	inc = ipv6_addr_is_multicast(daddr);
835 
836 	ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
837 	if (ifp) {
838 have_ifp:
839 		if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
840 			if (dad) {
841 				if (nonce != 0 && ifp->dad_nonce == nonce) {
842 					u8 *np = (u8 *)&nonce;
843 					/* Matching nonce if looped back */
844 					ND_PRINTK(2, notice,
845 						  "%s: IPv6 DAD loopback for address %pI6c nonce %pM ignored\n",
846 						  ifp->idev->dev->name,
847 						  &ifp->addr, np);
848 					goto out;
849 				}
850 				/*
851 				 * We are colliding with another node
852 				 * who is doing DAD
853 				 * so fail our DAD process
854 				 */
855 				addrconf_dad_failure(skb, ifp);
856 				return;
857 			} else {
858 				/*
859 				 * This is not a dad solicitation.
860 				 * If we are an optimistic node,
861 				 * we should respond.
862 				 * Otherwise, we should ignore it.
863 				 */
864 				if (!(ifp->flags & IFA_F_OPTIMISTIC))
865 					goto out;
866 			}
867 		}
868 
869 		idev = ifp->idev;
870 	} else {
871 		struct net *net = dev_net(dev);
872 
873 		/* perhaps an address on the master device */
874 		if (netif_is_l3_slave(dev)) {
875 			struct net_device *mdev;
876 
877 			mdev = netdev_master_upper_dev_get_rcu(dev);
878 			if (mdev) {
879 				ifp = ipv6_get_ifaddr(net, &msg->target, mdev, 1);
880 				if (ifp)
881 					goto have_ifp;
882 			}
883 		}
884 
885 		idev = in6_dev_get(dev);
886 		if (!idev) {
887 			/* XXX: count this drop? */
888 			return;
889 		}
890 
891 		if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
892 		    (idev->cnf.forwarding &&
893 		     (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
894 		     (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
895 			if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
896 			    skb->pkt_type != PACKET_HOST &&
897 			    inc &&
898 			    NEIGH_VAR(idev->nd_parms, PROXY_DELAY) != 0) {
899 				/*
900 				 * for anycast or proxy,
901 				 * sender should delay its response
902 				 * by a random time between 0 and
903 				 * MAX_ANYCAST_DELAY_TIME seconds.
904 				 * (RFC2461) -- yoshfuji
905 				 */
906 				struct sk_buff *n = skb_clone(skb, GFP_ATOMIC);
907 				if (n)
908 					pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
909 				goto out;
910 			}
911 		} else
912 			goto out;
913 	}
914 
915 	if (is_router < 0)
916 		is_router = idev->cnf.forwarding;
917 
918 	if (dad) {
919 		ndisc_send_na(dev, &in6addr_linklocal_allnodes, &msg->target,
920 			      !!is_router, false, (ifp != NULL), true);
921 		goto out;
922 	}
923 
924 	if (inc)
925 		NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_mcast);
926 	else
927 		NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_ucast);
928 
929 	/*
930 	 *	update / create cache entry
931 	 *	for the source address
932 	 */
933 	neigh = __neigh_lookup(&nd_tbl, saddr, dev,
934 			       !inc || lladdr || !dev->addr_len);
935 	if (neigh)
936 		ndisc_update(dev, neigh, lladdr, NUD_STALE,
937 			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
938 			     NEIGH_UPDATE_F_OVERRIDE,
939 			     NDISC_NEIGHBOUR_SOLICITATION, &ndopts);
940 	if (neigh || !dev->header_ops) {
941 		ndisc_send_na(dev, saddr, &msg->target, !!is_router,
942 			      true, (ifp != NULL && inc), inc);
943 		if (neigh)
944 			neigh_release(neigh);
945 	}
946 
947 out:
948 	if (ifp)
949 		in6_ifa_put(ifp);
950 	else
951 		in6_dev_put(idev);
952 }
953 
954 static void ndisc_recv_na(struct sk_buff *skb)
955 {
956 	struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
957 	struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
958 	const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
959 	u8 *lladdr = NULL;
960 	u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
961 				    offsetof(struct nd_msg, opt));
962 	struct ndisc_options ndopts;
963 	struct net_device *dev = skb->dev;
964 	struct inet6_dev *idev = __in6_dev_get(dev);
965 	struct inet6_ifaddr *ifp;
966 	struct neighbour *neigh;
967 
968 	if (skb->len < sizeof(struct nd_msg)) {
969 		ND_PRINTK(2, warn, "NA: packet too short\n");
970 		return;
971 	}
972 
973 	if (ipv6_addr_is_multicast(&msg->target)) {
974 		ND_PRINTK(2, warn, "NA: target address is multicast\n");
975 		return;
976 	}
977 
978 	if (ipv6_addr_is_multicast(daddr) &&
979 	    msg->icmph.icmp6_solicited) {
980 		ND_PRINTK(2, warn, "NA: solicited NA is multicasted\n");
981 		return;
982 	}
983 
984 	/* For some 802.11 wireless deployments (and possibly other networks),
985 	 * there will be a NA proxy and unsolicitd packets are attacks
986 	 * and thus should not be accepted.
987 	 */
988 	if (!msg->icmph.icmp6_solicited && idev &&
989 	    idev->cnf.drop_unsolicited_na)
990 		return;
991 
992 	if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts)) {
993 		ND_PRINTK(2, warn, "NS: invalid ND option\n");
994 		return;
995 	}
996 	if (ndopts.nd_opts_tgt_lladdr) {
997 		lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev);
998 		if (!lladdr) {
999 			ND_PRINTK(2, warn,
1000 				  "NA: invalid link-layer address length\n");
1001 			return;
1002 		}
1003 	}
1004 	ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
1005 	if (ifp) {
1006 		if (skb->pkt_type != PACKET_LOOPBACK
1007 		    && (ifp->flags & IFA_F_TENTATIVE)) {
1008 				addrconf_dad_failure(skb, ifp);
1009 				return;
1010 		}
1011 		/* What should we make now? The advertisement
1012 		   is invalid, but ndisc specs say nothing
1013 		   about it. It could be misconfiguration, or
1014 		   an smart proxy agent tries to help us :-)
1015 
1016 		   We should not print the error if NA has been
1017 		   received from loopback - it is just our own
1018 		   unsolicited advertisement.
1019 		 */
1020 		if (skb->pkt_type != PACKET_LOOPBACK)
1021 			ND_PRINTK(1, warn,
1022 				  "NA: %pM advertised our address %pI6c on %s!\n",
1023 				  eth_hdr(skb)->h_source, &ifp->addr, ifp->idev->dev->name);
1024 		in6_ifa_put(ifp);
1025 		return;
1026 	}
1027 	neigh = neigh_lookup(&nd_tbl, &msg->target, dev);
1028 
1029 	if (neigh) {
1030 		u8 old_flags = neigh->flags;
1031 		struct net *net = dev_net(dev);
1032 
1033 		if (neigh->nud_state & NUD_FAILED)
1034 			goto out;
1035 
1036 		/*
1037 		 * Don't update the neighbor cache entry on a proxy NA from
1038 		 * ourselves because either the proxied node is off link or it
1039 		 * has already sent a NA to us.
1040 		 */
1041 		if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
1042 		    net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
1043 		    pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
1044 			/* XXX: idev->cnf.proxy_ndp */
1045 			goto out;
1046 		}
1047 
1048 		ndisc_update(dev, neigh, lladdr,
1049 			     msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE,
1050 			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
1051 			     (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)|
1052 			     NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1053 			     (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0),
1054 			     NDISC_NEIGHBOUR_ADVERTISEMENT, &ndopts);
1055 
1056 		if ((old_flags & ~neigh->flags) & NTF_ROUTER) {
1057 			/*
1058 			 * Change: router to host
1059 			 */
1060 			rt6_clean_tohost(dev_net(dev),  saddr);
1061 		}
1062 
1063 out:
1064 		neigh_release(neigh);
1065 	}
1066 }
1067 
1068 static void ndisc_recv_rs(struct sk_buff *skb)
1069 {
1070 	struct rs_msg *rs_msg = (struct rs_msg *)skb_transport_header(skb);
1071 	unsigned long ndoptlen = skb->len - sizeof(*rs_msg);
1072 	struct neighbour *neigh;
1073 	struct inet6_dev *idev;
1074 	const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
1075 	struct ndisc_options ndopts;
1076 	u8 *lladdr = NULL;
1077 
1078 	if (skb->len < sizeof(*rs_msg))
1079 		return;
1080 
1081 	idev = __in6_dev_get(skb->dev);
1082 	if (!idev) {
1083 		ND_PRINTK(1, err, "RS: can't find in6 device\n");
1084 		return;
1085 	}
1086 
1087 	/* Don't accept RS if we're not in router mode */
1088 	if (!idev->cnf.forwarding)
1089 		goto out;
1090 
1091 	/*
1092 	 * Don't update NCE if src = ::;
1093 	 * this implies that the source node has no ip address assigned yet.
1094 	 */
1095 	if (ipv6_addr_any(saddr))
1096 		goto out;
1097 
1098 	/* Parse ND options */
1099 	if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts)) {
1100 		ND_PRINTK(2, notice, "NS: invalid ND option, ignored\n");
1101 		goto out;
1102 	}
1103 
1104 	if (ndopts.nd_opts_src_lladdr) {
1105 		lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1106 					     skb->dev);
1107 		if (!lladdr)
1108 			goto out;
1109 	}
1110 
1111 	neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1);
1112 	if (neigh) {
1113 		ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1114 			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
1115 			     NEIGH_UPDATE_F_OVERRIDE|
1116 			     NEIGH_UPDATE_F_OVERRIDE_ISROUTER,
1117 			     NDISC_ROUTER_SOLICITATION, &ndopts);
1118 		neigh_release(neigh);
1119 	}
1120 out:
1121 	return;
1122 }
1123 
1124 static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt)
1125 {
1126 	struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra);
1127 	struct sk_buff *skb;
1128 	struct nlmsghdr *nlh;
1129 	struct nduseroptmsg *ndmsg;
1130 	struct net *net = dev_net(ra->dev);
1131 	int err;
1132 	int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg)
1133 				    + (opt->nd_opt_len << 3));
1134 	size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr));
1135 
1136 	skb = nlmsg_new(msg_size, GFP_ATOMIC);
1137 	if (!skb) {
1138 		err = -ENOBUFS;
1139 		goto errout;
1140 	}
1141 
1142 	nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0);
1143 	if (!nlh) {
1144 		goto nla_put_failure;
1145 	}
1146 
1147 	ndmsg = nlmsg_data(nlh);
1148 	ndmsg->nduseropt_family = AF_INET6;
1149 	ndmsg->nduseropt_ifindex = ra->dev->ifindex;
1150 	ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type;
1151 	ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code;
1152 	ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3;
1153 
1154 	memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);
1155 
1156 	if (nla_put_in6_addr(skb, NDUSEROPT_SRCADDR, &ipv6_hdr(ra)->saddr))
1157 		goto nla_put_failure;
1158 	nlmsg_end(skb, nlh);
1159 
1160 	rtnl_notify(skb, net, 0, RTNLGRP_ND_USEROPT, NULL, GFP_ATOMIC);
1161 	return;
1162 
1163 nla_put_failure:
1164 	nlmsg_free(skb);
1165 	err = -EMSGSIZE;
1166 errout:
1167 	rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err);
1168 }
1169 
1170 static void ndisc_router_discovery(struct sk_buff *skb)
1171 {
1172 	struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
1173 	struct neighbour *neigh = NULL;
1174 	struct inet6_dev *in6_dev;
1175 	struct fib6_info *rt = NULL;
1176 	u32 defrtr_usr_metric;
1177 	struct net *net;
1178 	int lifetime;
1179 	struct ndisc_options ndopts;
1180 	int optlen;
1181 	unsigned int pref = 0;
1182 	__u32 old_if_flags;
1183 	bool send_ifinfo_notify = false;
1184 
1185 	__u8 *opt = (__u8 *)(ra_msg + 1);
1186 
1187 	optlen = (skb_tail_pointer(skb) - skb_transport_header(skb)) -
1188 		sizeof(struct ra_msg);
1189 
1190 	ND_PRINTK(2, info,
1191 		  "RA: %s, dev: %s\n",
1192 		  __func__, skb->dev->name);
1193 	if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1194 		ND_PRINTK(2, warn, "RA: source address is not link-local\n");
1195 		return;
1196 	}
1197 	if (optlen < 0) {
1198 		ND_PRINTK(2, warn, "RA: packet too short\n");
1199 		return;
1200 	}
1201 
1202 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1203 	if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
1204 		ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
1205 		return;
1206 	}
1207 #endif
1208 
1209 	/*
1210 	 *	set the RA_RECV flag in the interface
1211 	 */
1212 
1213 	in6_dev = __in6_dev_get(skb->dev);
1214 	if (!in6_dev) {
1215 		ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n",
1216 			  skb->dev->name);
1217 		return;
1218 	}
1219 
1220 	if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) {
1221 		ND_PRINTK(2, warn, "RA: invalid ND options\n");
1222 		return;
1223 	}
1224 
1225 	if (!ipv6_accept_ra(in6_dev)) {
1226 		ND_PRINTK(2, info,
1227 			  "RA: %s, did not accept ra for dev: %s\n",
1228 			  __func__, skb->dev->name);
1229 		goto skip_linkparms;
1230 	}
1231 
1232 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1233 	/* skip link-specific parameters from interior routers */
1234 	if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1235 		ND_PRINTK(2, info,
1236 			  "RA: %s, nodetype is NODEFAULT, dev: %s\n",
1237 			  __func__, skb->dev->name);
1238 		goto skip_linkparms;
1239 	}
1240 #endif
1241 
1242 	if (in6_dev->if_flags & IF_RS_SENT) {
1243 		/*
1244 		 *	flag that an RA was received after an RS was sent
1245 		 *	out on this interface.
1246 		 */
1247 		in6_dev->if_flags |= IF_RA_RCVD;
1248 	}
1249 
1250 	/*
1251 	 * Remember the managed/otherconf flags from most recently
1252 	 * received RA message (RFC 2462) -- yoshfuji
1253 	 */
1254 	old_if_flags = in6_dev->if_flags;
1255 	in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
1256 				IF_RA_OTHERCONF)) |
1257 				(ra_msg->icmph.icmp6_addrconf_managed ?
1258 					IF_RA_MANAGED : 0) |
1259 				(ra_msg->icmph.icmp6_addrconf_other ?
1260 					IF_RA_OTHERCONF : 0);
1261 
1262 	if (old_if_flags != in6_dev->if_flags)
1263 		send_ifinfo_notify = true;
1264 
1265 	if (!in6_dev->cnf.accept_ra_defrtr) {
1266 		ND_PRINTK(2, info,
1267 			  "RA: %s, defrtr is false for dev: %s\n",
1268 			  __func__, skb->dev->name);
1269 		goto skip_defrtr;
1270 	}
1271 
1272 	/* Do not accept RA with source-addr found on local machine unless
1273 	 * accept_ra_from_local is set to true.
1274 	 */
1275 	net = dev_net(in6_dev->dev);
1276 	if (!in6_dev->cnf.accept_ra_from_local &&
1277 	    ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) {
1278 		ND_PRINTK(2, info,
1279 			  "RA from local address detected on dev: %s: default router ignored\n",
1280 			  skb->dev->name);
1281 		goto skip_defrtr;
1282 	}
1283 
1284 	lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
1285 
1286 #ifdef CONFIG_IPV6_ROUTER_PREF
1287 	pref = ra_msg->icmph.icmp6_router_pref;
1288 	/* 10b is handled as if it were 00b (medium) */
1289 	if (pref == ICMPV6_ROUTER_PREF_INVALID ||
1290 	    !in6_dev->cnf.accept_ra_rtr_pref)
1291 		pref = ICMPV6_ROUTER_PREF_MEDIUM;
1292 #endif
1293 	/* routes added from RAs do not use nexthop objects */
1294 	rt = rt6_get_dflt_router(net, &ipv6_hdr(skb)->saddr, skb->dev);
1295 	if (rt) {
1296 		neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1297 					 rt->fib6_nh->fib_nh_dev, NULL,
1298 					  &ipv6_hdr(skb)->saddr);
1299 		if (!neigh) {
1300 			ND_PRINTK(0, err,
1301 				  "RA: %s got default router without neighbour\n",
1302 				  __func__);
1303 			fib6_info_release(rt);
1304 			return;
1305 		}
1306 	}
1307 	/* Set default route metric as specified by user */
1308 	defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric;
1309 	/* delete the route if lifetime is 0 or if metric needs change */
1310 	if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) {
1311 		ip6_del_rt(net, rt, false);
1312 		rt = NULL;
1313 	}
1314 
1315 	ND_PRINTK(3, info, "RA: rt: %p  lifetime: %d, metric: %d, for dev: %s\n",
1316 		  rt, lifetime, defrtr_usr_metric, skb->dev->name);
1317 	if (!rt && lifetime) {
1318 		ND_PRINTK(3, info, "RA: adding default router\n");
1319 
1320 		rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr,
1321 					 skb->dev, pref, defrtr_usr_metric);
1322 		if (!rt) {
1323 			ND_PRINTK(0, err,
1324 				  "RA: %s failed to add default route\n",
1325 				  __func__);
1326 			return;
1327 		}
1328 
1329 		neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1330 					 rt->fib6_nh->fib_nh_dev, NULL,
1331 					  &ipv6_hdr(skb)->saddr);
1332 		if (!neigh) {
1333 			ND_PRINTK(0, err,
1334 				  "RA: %s got default router without neighbour\n",
1335 				  __func__);
1336 			fib6_info_release(rt);
1337 			return;
1338 		}
1339 		neigh->flags |= NTF_ROUTER;
1340 	} else if (rt) {
1341 		rt->fib6_flags = (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
1342 	}
1343 
1344 	if (rt)
1345 		fib6_set_expires(rt, jiffies + (HZ * lifetime));
1346 	if (in6_dev->cnf.accept_ra_min_hop_limit < 256 &&
1347 	    ra_msg->icmph.icmp6_hop_limit) {
1348 		if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) {
1349 			in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
1350 			fib6_metric_set(rt, RTAX_HOPLIMIT,
1351 					ra_msg->icmph.icmp6_hop_limit);
1352 		} else {
1353 			ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n");
1354 		}
1355 	}
1356 
1357 skip_defrtr:
1358 
1359 	/*
1360 	 *	Update Reachable Time and Retrans Timer
1361 	 */
1362 
1363 	if (in6_dev->nd_parms) {
1364 		unsigned long rtime = ntohl(ra_msg->retrans_timer);
1365 
1366 		if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) {
1367 			rtime = (rtime*HZ)/1000;
1368 			if (rtime < HZ/100)
1369 				rtime = HZ/100;
1370 			NEIGH_VAR_SET(in6_dev->nd_parms, RETRANS_TIME, rtime);
1371 			in6_dev->tstamp = jiffies;
1372 			send_ifinfo_notify = true;
1373 		}
1374 
1375 		rtime = ntohl(ra_msg->reachable_time);
1376 		if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
1377 			rtime = (rtime*HZ)/1000;
1378 
1379 			if (rtime < HZ/10)
1380 				rtime = HZ/10;
1381 
1382 			if (rtime != NEIGH_VAR(in6_dev->nd_parms, BASE_REACHABLE_TIME)) {
1383 				NEIGH_VAR_SET(in6_dev->nd_parms,
1384 					      BASE_REACHABLE_TIME, rtime);
1385 				NEIGH_VAR_SET(in6_dev->nd_parms,
1386 					      GC_STALETIME, 3 * rtime);
1387 				in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
1388 				in6_dev->tstamp = jiffies;
1389 				send_ifinfo_notify = true;
1390 			}
1391 		}
1392 	}
1393 
1394 	/*
1395 	 *	Send a notify if RA changed managed/otherconf flags or timer settings
1396 	 */
1397 	if (send_ifinfo_notify)
1398 		inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
1399 
1400 skip_linkparms:
1401 
1402 	/*
1403 	 *	Process options.
1404 	 */
1405 
1406 	if (!neigh)
1407 		neigh = __neigh_lookup(&nd_tbl, &ipv6_hdr(skb)->saddr,
1408 				       skb->dev, 1);
1409 	if (neigh) {
1410 		u8 *lladdr = NULL;
1411 		if (ndopts.nd_opts_src_lladdr) {
1412 			lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1413 						     skb->dev);
1414 			if (!lladdr) {
1415 				ND_PRINTK(2, warn,
1416 					  "RA: invalid link-layer address length\n");
1417 				goto out;
1418 			}
1419 		}
1420 		ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1421 			     NEIGH_UPDATE_F_WEAK_OVERRIDE|
1422 			     NEIGH_UPDATE_F_OVERRIDE|
1423 			     NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1424 			     NEIGH_UPDATE_F_ISROUTER,
1425 			     NDISC_ROUTER_ADVERTISEMENT, &ndopts);
1426 	}
1427 
1428 	if (!ipv6_accept_ra(in6_dev)) {
1429 		ND_PRINTK(2, info,
1430 			  "RA: %s, accept_ra is false for dev: %s\n",
1431 			  __func__, skb->dev->name);
1432 		goto out;
1433 	}
1434 
1435 #ifdef CONFIG_IPV6_ROUTE_INFO
1436 	if (!in6_dev->cnf.accept_ra_from_local &&
1437 	    ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
1438 			  in6_dev->dev, 0)) {
1439 		ND_PRINTK(2, info,
1440 			  "RA from local address detected on dev: %s: router info ignored.\n",
1441 			  skb->dev->name);
1442 		goto skip_routeinfo;
1443 	}
1444 
1445 	if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
1446 		struct nd_opt_hdr *p;
1447 		for (p = ndopts.nd_opts_ri;
1448 		     p;
1449 		     p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
1450 			struct route_info *ri = (struct route_info *)p;
1451 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1452 			if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT &&
1453 			    ri->prefix_len == 0)
1454 				continue;
1455 #endif
1456 			if (ri->prefix_len == 0 &&
1457 			    !in6_dev->cnf.accept_ra_defrtr)
1458 				continue;
1459 			if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
1460 				continue;
1461 			if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
1462 				continue;
1463 			rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3,
1464 				      &ipv6_hdr(skb)->saddr);
1465 		}
1466 	}
1467 
1468 skip_routeinfo:
1469 #endif
1470 
1471 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1472 	/* skip link-specific ndopts from interior routers */
1473 	if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1474 		ND_PRINTK(2, info,
1475 			  "RA: %s, nodetype is NODEFAULT (interior routes), dev: %s\n",
1476 			  __func__, skb->dev->name);
1477 		goto out;
1478 	}
1479 #endif
1480 
1481 	if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
1482 		struct nd_opt_hdr *p;
1483 		for (p = ndopts.nd_opts_pi;
1484 		     p;
1485 		     p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
1486 			addrconf_prefix_rcv(skb->dev, (u8 *)p,
1487 					    (p->nd_opt_len) << 3,
1488 					    ndopts.nd_opts_src_lladdr != NULL);
1489 		}
1490 	}
1491 
1492 	if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) {
1493 		__be32 n;
1494 		u32 mtu;
1495 
1496 		memcpy(&n, ((u8 *)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu));
1497 		mtu = ntohl(n);
1498 
1499 		if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
1500 			ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
1501 		} else if (in6_dev->cnf.mtu6 != mtu) {
1502 			in6_dev->cnf.mtu6 = mtu;
1503 			fib6_metric_set(rt, RTAX_MTU, mtu);
1504 			rt6_mtu_change(skb->dev, mtu);
1505 		}
1506 	}
1507 
1508 	if (ndopts.nd_useropts) {
1509 		struct nd_opt_hdr *p;
1510 		for (p = ndopts.nd_useropts;
1511 		     p;
1512 		     p = ndisc_next_useropt(skb->dev, p,
1513 					    ndopts.nd_useropts_end)) {
1514 			ndisc_ra_useropt(skb, p);
1515 		}
1516 	}
1517 
1518 	if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
1519 		ND_PRINTK(2, warn, "RA: invalid RA options\n");
1520 	}
1521 out:
1522 	fib6_info_release(rt);
1523 	if (neigh)
1524 		neigh_release(neigh);
1525 }
1526 
1527 static void ndisc_redirect_rcv(struct sk_buff *skb)
1528 {
1529 	u8 *hdr;
1530 	struct ndisc_options ndopts;
1531 	struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb);
1532 	u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
1533 				    offsetof(struct rd_msg, opt));
1534 
1535 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1536 	switch (skb->ndisc_nodetype) {
1537 	case NDISC_NODETYPE_HOST:
1538 	case NDISC_NODETYPE_NODEFAULT:
1539 		ND_PRINTK(2, warn,
1540 			  "Redirect: from host or unauthorized router\n");
1541 		return;
1542 	}
1543 #endif
1544 
1545 	if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1546 		ND_PRINTK(2, warn,
1547 			  "Redirect: source address is not link-local\n");
1548 		return;
1549 	}
1550 
1551 	if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
1552 		return;
1553 
1554 	if (!ndopts.nd_opts_rh) {
1555 		ip6_redirect_no_header(skb, dev_net(skb->dev),
1556 					skb->dev->ifindex);
1557 		return;
1558 	}
1559 
1560 	hdr = (u8 *)ndopts.nd_opts_rh;
1561 	hdr += 8;
1562 	if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
1563 		return;
1564 
1565 	icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
1566 }
1567 
1568 static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb,
1569 					   struct sk_buff *orig_skb,
1570 					   int rd_len)
1571 {
1572 	u8 *opt = skb_put(skb, rd_len);
1573 
1574 	memset(opt, 0, 8);
1575 	*(opt++) = ND_OPT_REDIRECT_HDR;
1576 	*(opt++) = (rd_len >> 3);
1577 	opt += 6;
1578 
1579 	skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt,
1580 		      rd_len - 8);
1581 }
1582 
1583 void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
1584 {
1585 	struct net_device *dev = skb->dev;
1586 	struct net *net = dev_net(dev);
1587 	struct sock *sk = net->ipv6.ndisc_sk;
1588 	int optlen = 0;
1589 	struct inet_peer *peer;
1590 	struct sk_buff *buff;
1591 	struct rd_msg *msg;
1592 	struct in6_addr saddr_buf;
1593 	struct rt6_info *rt;
1594 	struct dst_entry *dst;
1595 	struct flowi6 fl6;
1596 	int rd_len;
1597 	u8 ha_buf[MAX_ADDR_LEN], *ha = NULL,
1598 	   ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL;
1599 	bool ret;
1600 
1601 	if (netif_is_l3_master(skb->dev)) {
1602 		dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
1603 		if (!dev)
1604 			return;
1605 	}
1606 
1607 	if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
1608 		ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
1609 			  dev->name);
1610 		return;
1611 	}
1612 
1613 	if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) &&
1614 	    ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
1615 		ND_PRINTK(2, warn,
1616 			  "Redirect: target address is not link-local unicast\n");
1617 		return;
1618 	}
1619 
1620 	icmpv6_flow_init(sk, &fl6, NDISC_REDIRECT,
1621 			 &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex);
1622 
1623 	dst = ip6_route_output(net, NULL, &fl6);
1624 	if (dst->error) {
1625 		dst_release(dst);
1626 		return;
1627 	}
1628 	dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
1629 	if (IS_ERR(dst))
1630 		return;
1631 
1632 	rt = (struct rt6_info *) dst;
1633 
1634 	if (rt->rt6i_flags & RTF_GATEWAY) {
1635 		ND_PRINTK(2, warn,
1636 			  "Redirect: destination is not a neighbour\n");
1637 		goto release;
1638 	}
1639 	peer = inet_getpeer_v6(net->ipv6.peers, &ipv6_hdr(skb)->saddr, 1);
1640 	ret = inet_peer_xrlim_allow(peer, 1*HZ);
1641 	if (peer)
1642 		inet_putpeer(peer);
1643 	if (!ret)
1644 		goto release;
1645 
1646 	if (dev->addr_len) {
1647 		struct neighbour *neigh = dst_neigh_lookup(skb_dst(skb), target);
1648 		if (!neigh) {
1649 			ND_PRINTK(2, warn,
1650 				  "Redirect: no neigh for target address\n");
1651 			goto release;
1652 		}
1653 
1654 		read_lock_bh(&neigh->lock);
1655 		if (neigh->nud_state & NUD_VALID) {
1656 			memcpy(ha_buf, neigh->ha, dev->addr_len);
1657 			read_unlock_bh(&neigh->lock);
1658 			ha = ha_buf;
1659 			optlen += ndisc_redirect_opt_addr_space(dev, neigh,
1660 								ops_data_buf,
1661 								&ops_data);
1662 		} else
1663 			read_unlock_bh(&neigh->lock);
1664 
1665 		neigh_release(neigh);
1666 	}
1667 
1668 	rd_len = min_t(unsigned int,
1669 		       IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen,
1670 		       skb->len + 8);
1671 	rd_len &= ~0x7;
1672 	optlen += rd_len;
1673 
1674 	buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
1675 	if (!buff)
1676 		goto release;
1677 
1678 	msg = skb_put(buff, sizeof(*msg));
1679 	*msg = (struct rd_msg) {
1680 		.icmph = {
1681 			.icmp6_type = NDISC_REDIRECT,
1682 		},
1683 		.target = *target,
1684 		.dest = ipv6_hdr(skb)->daddr,
1685 	};
1686 
1687 	/*
1688 	 *	include target_address option
1689 	 */
1690 
1691 	if (ha)
1692 		ndisc_fill_redirect_addr_option(buff, ha, ops_data);
1693 
1694 	/*
1695 	 *	build redirect option and copy skb over to the new packet.
1696 	 */
1697 
1698 	if (rd_len)
1699 		ndisc_fill_redirect_hdr_option(buff, skb, rd_len);
1700 
1701 	skb_dst_set(buff, dst);
1702 	ndisc_send_skb(buff, &ipv6_hdr(skb)->saddr, &saddr_buf);
1703 	return;
1704 
1705 release:
1706 	dst_release(dst);
1707 }
1708 
1709 static void pndisc_redo(struct sk_buff *skb)
1710 {
1711 	ndisc_recv_ns(skb);
1712 	kfree_skb(skb);
1713 }
1714 
1715 static int ndisc_is_multicast(const void *pkey)
1716 {
1717 	return ipv6_addr_is_multicast((struct in6_addr *)pkey);
1718 }
1719 
1720 static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
1721 {
1722 	struct inet6_dev *idev = __in6_dev_get(skb->dev);
1723 
1724 	if (!idev)
1725 		return true;
1726 	if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
1727 	    idev->cnf.suppress_frag_ndisc) {
1728 		net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
1729 		return true;
1730 	}
1731 	return false;
1732 }
1733 
1734 int ndisc_rcv(struct sk_buff *skb)
1735 {
1736 	struct nd_msg *msg;
1737 
1738 	if (ndisc_suppress_frag_ndisc(skb))
1739 		return 0;
1740 
1741 	if (skb_linearize(skb))
1742 		return 0;
1743 
1744 	msg = (struct nd_msg *)skb_transport_header(skb);
1745 
1746 	__skb_push(skb, skb->data - skb_transport_header(skb));
1747 
1748 	if (ipv6_hdr(skb)->hop_limit != 255) {
1749 		ND_PRINTK(2, warn, "NDISC: invalid hop-limit: %d\n",
1750 			  ipv6_hdr(skb)->hop_limit);
1751 		return 0;
1752 	}
1753 
1754 	if (msg->icmph.icmp6_code != 0) {
1755 		ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n",
1756 			  msg->icmph.icmp6_code);
1757 		return 0;
1758 	}
1759 
1760 	switch (msg->icmph.icmp6_type) {
1761 	case NDISC_NEIGHBOUR_SOLICITATION:
1762 		memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
1763 		ndisc_recv_ns(skb);
1764 		break;
1765 
1766 	case NDISC_NEIGHBOUR_ADVERTISEMENT:
1767 		ndisc_recv_na(skb);
1768 		break;
1769 
1770 	case NDISC_ROUTER_SOLICITATION:
1771 		ndisc_recv_rs(skb);
1772 		break;
1773 
1774 	case NDISC_ROUTER_ADVERTISEMENT:
1775 		ndisc_router_discovery(skb);
1776 		break;
1777 
1778 	case NDISC_REDIRECT:
1779 		ndisc_redirect_rcv(skb);
1780 		break;
1781 	}
1782 
1783 	return 0;
1784 }
1785 
1786 static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1787 {
1788 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1789 	struct netdev_notifier_change_info *change_info;
1790 	struct net *net = dev_net(dev);
1791 	struct inet6_dev *idev;
1792 
1793 	switch (event) {
1794 	case NETDEV_CHANGEADDR:
1795 		neigh_changeaddr(&nd_tbl, dev);
1796 		fib6_run_gc(0, net, false);
1797 		fallthrough;
1798 	case NETDEV_UP:
1799 		idev = in6_dev_get(dev);
1800 		if (!idev)
1801 			break;
1802 		if (idev->cnf.ndisc_notify ||
1803 		    net->ipv6.devconf_all->ndisc_notify)
1804 			ndisc_send_unsol_na(dev);
1805 		in6_dev_put(idev);
1806 		break;
1807 	case NETDEV_CHANGE:
1808 		change_info = ptr;
1809 		if (change_info->flags_changed & IFF_NOARP)
1810 			neigh_changeaddr(&nd_tbl, dev);
1811 		if (!netif_carrier_ok(dev))
1812 			neigh_carrier_down(&nd_tbl, dev);
1813 		break;
1814 	case NETDEV_DOWN:
1815 		neigh_ifdown(&nd_tbl, dev);
1816 		fib6_run_gc(0, net, false);
1817 		break;
1818 	case NETDEV_NOTIFY_PEERS:
1819 		ndisc_send_unsol_na(dev);
1820 		break;
1821 	default:
1822 		break;
1823 	}
1824 
1825 	return NOTIFY_DONE;
1826 }
1827 
1828 static struct notifier_block ndisc_netdev_notifier = {
1829 	.notifier_call = ndisc_netdev_event,
1830 	.priority = ADDRCONF_NOTIFY_PRIORITY - 5,
1831 };
1832 
1833 #ifdef CONFIG_SYSCTL
1834 static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
1835 					 const char *func, const char *dev_name)
1836 {
1837 	static char warncomm[TASK_COMM_LEN];
1838 	static int warned;
1839 	if (strcmp(warncomm, current->comm) && warned < 5) {
1840 		strcpy(warncomm, current->comm);
1841 		pr_warn("process `%s' is using deprecated sysctl (%s) net.ipv6.neigh.%s.%s - use net.ipv6.neigh.%s.%s_ms instead\n",
1842 			warncomm, func,
1843 			dev_name, ctl->procname,
1844 			dev_name, ctl->procname);
1845 		warned++;
1846 	}
1847 }
1848 
1849 int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer,
1850 		size_t *lenp, loff_t *ppos)
1851 {
1852 	struct net_device *dev = ctl->extra1;
1853 	struct inet6_dev *idev;
1854 	int ret;
1855 
1856 	if ((strcmp(ctl->procname, "retrans_time") == 0) ||
1857 	    (strcmp(ctl->procname, "base_reachable_time") == 0))
1858 		ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");
1859 
1860 	if (strcmp(ctl->procname, "retrans_time") == 0)
1861 		ret = neigh_proc_dointvec(ctl, write, buffer, lenp, ppos);
1862 
1863 	else if (strcmp(ctl->procname, "base_reachable_time") == 0)
1864 		ret = neigh_proc_dointvec_jiffies(ctl, write,
1865 						  buffer, lenp, ppos);
1866 
1867 	else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
1868 		 (strcmp(ctl->procname, "base_reachable_time_ms") == 0))
1869 		ret = neigh_proc_dointvec_ms_jiffies(ctl, write,
1870 						     buffer, lenp, ppos);
1871 	else
1872 		ret = -1;
1873 
1874 	if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
1875 		if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME))
1876 			idev->nd_parms->reachable_time =
1877 					neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME));
1878 		idev->tstamp = jiffies;
1879 		inet6_ifinfo_notify(RTM_NEWLINK, idev);
1880 		in6_dev_put(idev);
1881 	}
1882 	return ret;
1883 }
1884 
1885 
1886 #endif
1887 
1888 static int __net_init ndisc_net_init(struct net *net)
1889 {
1890 	struct ipv6_pinfo *np;
1891 	struct sock *sk;
1892 	int err;
1893 
1894 	err = inet_ctl_sock_create(&sk, PF_INET6,
1895 				   SOCK_RAW, IPPROTO_ICMPV6, net);
1896 	if (err < 0) {
1897 		ND_PRINTK(0, err,
1898 			  "NDISC: Failed to initialize the control socket (err %d)\n",
1899 			  err);
1900 		return err;
1901 	}
1902 
1903 	net->ipv6.ndisc_sk = sk;
1904 
1905 	np = inet6_sk(sk);
1906 	np->hop_limit = 255;
1907 	/* Do not loopback ndisc messages */
1908 	np->mc_loop = 0;
1909 
1910 	return 0;
1911 }
1912 
1913 static void __net_exit ndisc_net_exit(struct net *net)
1914 {
1915 	inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
1916 }
1917 
1918 static struct pernet_operations ndisc_net_ops = {
1919 	.init = ndisc_net_init,
1920 	.exit = ndisc_net_exit,
1921 };
1922 
1923 int __init ndisc_init(void)
1924 {
1925 	int err;
1926 
1927 	err = register_pernet_subsys(&ndisc_net_ops);
1928 	if (err)
1929 		return err;
1930 	/*
1931 	 * Initialize the neighbour table
1932 	 */
1933 	neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
1934 
1935 #ifdef CONFIG_SYSCTL
1936 	err = neigh_sysctl_register(NULL, &nd_tbl.parms,
1937 				    ndisc_ifinfo_sysctl_change);
1938 	if (err)
1939 		goto out_unregister_pernet;
1940 out:
1941 #endif
1942 	return err;
1943 
1944 #ifdef CONFIG_SYSCTL
1945 out_unregister_pernet:
1946 	unregister_pernet_subsys(&ndisc_net_ops);
1947 	goto out;
1948 #endif
1949 }
1950 
1951 int __init ndisc_late_init(void)
1952 {
1953 	return register_netdevice_notifier(&ndisc_netdev_notifier);
1954 }
1955 
1956 void ndisc_late_cleanup(void)
1957 {
1958 	unregister_netdevice_notifier(&ndisc_netdev_notifier);
1959 }
1960 
1961 void ndisc_cleanup(void)
1962 {
1963 #ifdef CONFIG_SYSCTL
1964 	neigh_sysctl_unregister(&nd_tbl.parms);
1965 #endif
1966 	neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl);
1967 	unregister_pernet_subsys(&ndisc_net_ops);
1968 }
1969