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_INTERVAL_PROBE_TIME_MS] = 5 * HZ,
132 [NEIGH_VAR_GC_STALETIME] = 60 * HZ,
133 [NEIGH_VAR_QUEUE_LEN_BYTES] = SK_WMEM_MAX,
134 [NEIGH_VAR_PROXY_QLEN] = 64,
135 [NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
136 [NEIGH_VAR_PROXY_DELAY] = (8 * HZ) / 10,
137 },
138 },
139 .gc_interval = 30 * HZ,
140 .gc_thresh1 = 128,
141 .gc_thresh2 = 512,
142 .gc_thresh3 = 1024,
143 };
144 EXPORT_SYMBOL_GPL(nd_tbl);
145
__ndisc_fill_addr_option(struct sk_buff * skb,int type,const void * data,int data_len,int pad)146 void __ndisc_fill_addr_option(struct sk_buff *skb, int type, const void *data,
147 int data_len, int pad)
148 {
149 int space = __ndisc_opt_addr_space(data_len, pad);
150 u8 *opt = skb_put(skb, space);
151
152 opt[0] = type;
153 opt[1] = space>>3;
154
155 memset(opt + 2, 0, pad);
156 opt += pad;
157 space -= pad;
158
159 memcpy(opt+2, data, data_len);
160 data_len += 2;
161 opt += data_len;
162 space -= data_len;
163 if (space > 0)
164 memset(opt, 0, space);
165 }
166 EXPORT_SYMBOL_GPL(__ndisc_fill_addr_option);
167
ndisc_fill_addr_option(struct sk_buff * skb,int type,const void * data,u8 icmp6_type)168 static inline void ndisc_fill_addr_option(struct sk_buff *skb, int type,
169 const void *data, u8 icmp6_type)
170 {
171 __ndisc_fill_addr_option(skb, type, data, skb->dev->addr_len,
172 ndisc_addr_option_pad(skb->dev->type));
173 ndisc_ops_fill_addr_option(skb->dev, skb, icmp6_type);
174 }
175
ndisc_fill_redirect_addr_option(struct sk_buff * skb,void * ha,const u8 * ops_data)176 static inline void ndisc_fill_redirect_addr_option(struct sk_buff *skb,
177 void *ha,
178 const u8 *ops_data)
179 {
180 ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR, ha, NDISC_REDIRECT);
181 ndisc_ops_fill_redirect_addr_option(skb->dev, skb, ops_data);
182 }
183
ndisc_next_option(struct nd_opt_hdr * cur,struct nd_opt_hdr * end)184 static struct nd_opt_hdr *ndisc_next_option(struct nd_opt_hdr *cur,
185 struct nd_opt_hdr *end)
186 {
187 int type;
188 if (!cur || !end || cur >= end)
189 return NULL;
190 type = cur->nd_opt_type;
191 do {
192 cur = ((void *)cur) + (cur->nd_opt_len << 3);
193 } while (cur < end && cur->nd_opt_type != type);
194 return cur <= end && cur->nd_opt_type == type ? cur : NULL;
195 }
196
ndisc_is_useropt(const struct net_device * dev,struct nd_opt_hdr * opt)197 static inline int ndisc_is_useropt(const struct net_device *dev,
198 struct nd_opt_hdr *opt)
199 {
200 return opt->nd_opt_type == ND_OPT_PREFIX_INFO ||
201 opt->nd_opt_type == ND_OPT_RDNSS ||
202 opt->nd_opt_type == ND_OPT_DNSSL ||
203 opt->nd_opt_type == ND_OPT_CAPTIVE_PORTAL ||
204 opt->nd_opt_type == ND_OPT_PREF64 ||
205 ndisc_ops_is_useropt(dev, opt->nd_opt_type);
206 }
207
ndisc_next_useropt(const struct net_device * dev,struct nd_opt_hdr * cur,struct nd_opt_hdr * end)208 static struct nd_opt_hdr *ndisc_next_useropt(const struct net_device *dev,
209 struct nd_opt_hdr *cur,
210 struct nd_opt_hdr *end)
211 {
212 if (!cur || !end || cur >= end)
213 return NULL;
214 do {
215 cur = ((void *)cur) + (cur->nd_opt_len << 3);
216 } while (cur < end && !ndisc_is_useropt(dev, cur));
217 return cur <= end && ndisc_is_useropt(dev, cur) ? cur : NULL;
218 }
219
ndisc_parse_options(const struct net_device * dev,u8 * opt,int opt_len,struct ndisc_options * ndopts)220 struct ndisc_options *ndisc_parse_options(const struct net_device *dev,
221 u8 *opt, int opt_len,
222 struct ndisc_options *ndopts)
223 {
224 struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)opt;
225
226 if (!nd_opt || opt_len < 0 || !ndopts)
227 return NULL;
228 memset(ndopts, 0, sizeof(*ndopts));
229 while (opt_len) {
230 int l;
231 if (opt_len < sizeof(struct nd_opt_hdr))
232 return NULL;
233 l = nd_opt->nd_opt_len << 3;
234 if (opt_len < l || l == 0)
235 return NULL;
236 if (ndisc_ops_parse_options(dev, nd_opt, ndopts))
237 goto next_opt;
238 switch (nd_opt->nd_opt_type) {
239 case ND_OPT_SOURCE_LL_ADDR:
240 case ND_OPT_TARGET_LL_ADDR:
241 case ND_OPT_MTU:
242 case ND_OPT_NONCE:
243 case ND_OPT_REDIRECT_HDR:
244 if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
245 ND_PRINTK(2, warn,
246 "%s: duplicated ND6 option found: type=%d\n",
247 __func__, nd_opt->nd_opt_type);
248 } else {
249 ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
250 }
251 break;
252 case ND_OPT_PREFIX_INFO:
253 ndopts->nd_opts_pi_end = nd_opt;
254 if (!ndopts->nd_opt_array[nd_opt->nd_opt_type])
255 ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
256 break;
257 #ifdef CONFIG_IPV6_ROUTE_INFO
258 case ND_OPT_ROUTE_INFO:
259 ndopts->nd_opts_ri_end = nd_opt;
260 if (!ndopts->nd_opts_ri)
261 ndopts->nd_opts_ri = nd_opt;
262 break;
263 #endif
264 default:
265 if (ndisc_is_useropt(dev, nd_opt)) {
266 ndopts->nd_useropts_end = nd_opt;
267 if (!ndopts->nd_useropts)
268 ndopts->nd_useropts = nd_opt;
269 } else {
270 /*
271 * Unknown options must be silently ignored,
272 * to accommodate future extension to the
273 * protocol.
274 */
275 ND_PRINTK(2, notice,
276 "%s: ignored unsupported option; type=%d, len=%d\n",
277 __func__,
278 nd_opt->nd_opt_type,
279 nd_opt->nd_opt_len);
280 }
281 }
282 next_opt:
283 opt_len -= l;
284 nd_opt = ((void *)nd_opt) + l;
285 }
286 return ndopts;
287 }
288
ndisc_mc_map(const struct in6_addr * addr,char * buf,struct net_device * dev,int dir)289 int ndisc_mc_map(const struct in6_addr *addr, char *buf, struct net_device *dev, int dir)
290 {
291 switch (dev->type) {
292 case ARPHRD_ETHER:
293 case ARPHRD_IEEE802: /* Not sure. Check it later. --ANK */
294 case ARPHRD_FDDI:
295 ipv6_eth_mc_map(addr, buf);
296 return 0;
297 case ARPHRD_ARCNET:
298 ipv6_arcnet_mc_map(addr, buf);
299 return 0;
300 case ARPHRD_INFINIBAND:
301 ipv6_ib_mc_map(addr, dev->broadcast, buf);
302 return 0;
303 case ARPHRD_IPGRE:
304 return ipv6_ipgre_mc_map(addr, dev->broadcast, buf);
305 default:
306 if (dir) {
307 memcpy(buf, dev->broadcast, dev->addr_len);
308 return 0;
309 }
310 }
311 return -EINVAL;
312 }
313 EXPORT_SYMBOL(ndisc_mc_map);
314
ndisc_hash(const void * pkey,const struct net_device * dev,__u32 * hash_rnd)315 static u32 ndisc_hash(const void *pkey,
316 const struct net_device *dev,
317 __u32 *hash_rnd)
318 {
319 return ndisc_hashfn(pkey, dev, hash_rnd);
320 }
321
ndisc_key_eq(const struct neighbour * n,const void * pkey)322 static bool ndisc_key_eq(const struct neighbour *n, const void *pkey)
323 {
324 return neigh_key_eq128(n, pkey);
325 }
326
ndisc_constructor(struct neighbour * neigh)327 static int ndisc_constructor(struct neighbour *neigh)
328 {
329 struct in6_addr *addr = (struct in6_addr *)&neigh->primary_key;
330 struct net_device *dev = neigh->dev;
331 struct inet6_dev *in6_dev;
332 struct neigh_parms *parms;
333 bool is_multicast = ipv6_addr_is_multicast(addr);
334
335 in6_dev = in6_dev_get(dev);
336 if (!in6_dev) {
337 return -EINVAL;
338 }
339
340 parms = in6_dev->nd_parms;
341 __neigh_parms_put(neigh->parms);
342 neigh->parms = neigh_parms_clone(parms);
343
344 neigh->type = is_multicast ? RTN_MULTICAST : RTN_UNICAST;
345 if (!dev->header_ops) {
346 neigh->nud_state = NUD_NOARP;
347 neigh->ops = &ndisc_direct_ops;
348 neigh->output = neigh_direct_output;
349 } else {
350 if (is_multicast) {
351 neigh->nud_state = NUD_NOARP;
352 ndisc_mc_map(addr, neigh->ha, dev, 1);
353 } else if (dev->flags&(IFF_NOARP|IFF_LOOPBACK)) {
354 neigh->nud_state = NUD_NOARP;
355 memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
356 if (dev->flags&IFF_LOOPBACK)
357 neigh->type = RTN_LOCAL;
358 } else if (dev->flags&IFF_POINTOPOINT) {
359 neigh->nud_state = NUD_NOARP;
360 memcpy(neigh->ha, dev->broadcast, dev->addr_len);
361 }
362 if (dev->header_ops->cache)
363 neigh->ops = &ndisc_hh_ops;
364 else
365 neigh->ops = &ndisc_generic_ops;
366 if (neigh->nud_state&NUD_VALID)
367 neigh->output = neigh->ops->connected_output;
368 else
369 neigh->output = neigh->ops->output;
370 }
371 in6_dev_put(in6_dev);
372 return 0;
373 }
374
pndisc_constructor(struct pneigh_entry * n)375 static int pndisc_constructor(struct pneigh_entry *n)
376 {
377 struct in6_addr *addr = (struct in6_addr *)&n->key;
378 struct in6_addr maddr;
379 struct net_device *dev = n->dev;
380
381 if (!dev || !__in6_dev_get(dev))
382 return -EINVAL;
383 addrconf_addr_solict_mult(addr, &maddr);
384 ipv6_dev_mc_inc(dev, &maddr);
385 return 0;
386 }
387
pndisc_destructor(struct pneigh_entry * n)388 static void pndisc_destructor(struct pneigh_entry *n)
389 {
390 struct in6_addr *addr = (struct in6_addr *)&n->key;
391 struct in6_addr maddr;
392 struct net_device *dev = n->dev;
393
394 if (!dev || !__in6_dev_get(dev))
395 return;
396 addrconf_addr_solict_mult(addr, &maddr);
397 ipv6_dev_mc_dec(dev, &maddr);
398 }
399
400 /* called with rtnl held */
ndisc_allow_add(const struct net_device * dev,struct netlink_ext_ack * extack)401 static bool ndisc_allow_add(const struct net_device *dev,
402 struct netlink_ext_ack *extack)
403 {
404 struct inet6_dev *idev = __in6_dev_get(dev);
405
406 if (!idev || idev->cnf.disable_ipv6) {
407 NL_SET_ERR_MSG(extack, "IPv6 is disabled on this device");
408 return false;
409 }
410
411 return true;
412 }
413
ndisc_alloc_skb(struct net_device * dev,int len)414 static struct sk_buff *ndisc_alloc_skb(struct net_device *dev,
415 int len)
416 {
417 int hlen = LL_RESERVED_SPACE(dev);
418 int tlen = dev->needed_tailroom;
419 struct sock *sk = dev_net(dev)->ipv6.ndisc_sk;
420 struct sk_buff *skb;
421
422 skb = alloc_skb(hlen + sizeof(struct ipv6hdr) + len + tlen, GFP_ATOMIC);
423 if (!skb) {
424 ND_PRINTK(0, err, "ndisc: %s failed to allocate an skb\n",
425 __func__);
426 return NULL;
427 }
428
429 skb->protocol = htons(ETH_P_IPV6);
430 skb->dev = dev;
431
432 skb_reserve(skb, hlen + sizeof(struct ipv6hdr));
433 skb_reset_transport_header(skb);
434
435 /* Manually assign socket ownership as we avoid calling
436 * sock_alloc_send_pskb() to bypass wmem buffer limits
437 */
438 skb_set_owner_w(skb, sk);
439
440 return skb;
441 }
442
ip6_nd_hdr(struct sk_buff * skb,const struct in6_addr * saddr,const struct in6_addr * daddr,int hop_limit,int len)443 static void ip6_nd_hdr(struct sk_buff *skb,
444 const struct in6_addr *saddr,
445 const struct in6_addr *daddr,
446 int hop_limit, int len)
447 {
448 struct ipv6hdr *hdr;
449 struct inet6_dev *idev;
450 unsigned tclass;
451
452 rcu_read_lock();
453 idev = __in6_dev_get(skb->dev);
454 tclass = idev ? idev->cnf.ndisc_tclass : 0;
455 rcu_read_unlock();
456
457 skb_push(skb, sizeof(*hdr));
458 skb_reset_network_header(skb);
459 hdr = ipv6_hdr(skb);
460
461 ip6_flow_hdr(hdr, tclass, 0);
462
463 hdr->payload_len = htons(len);
464 hdr->nexthdr = IPPROTO_ICMPV6;
465 hdr->hop_limit = hop_limit;
466
467 hdr->saddr = *saddr;
468 hdr->daddr = *daddr;
469 }
470
ndisc_send_skb(struct sk_buff * skb,const struct in6_addr * daddr,const struct in6_addr * saddr)471 void ndisc_send_skb(struct sk_buff *skb, const struct in6_addr *daddr,
472 const struct in6_addr *saddr)
473 {
474 struct dst_entry *dst = skb_dst(skb);
475 struct net *net = dev_net(skb->dev);
476 struct sock *sk = net->ipv6.ndisc_sk;
477 struct inet6_dev *idev;
478 int err;
479 struct icmp6hdr *icmp6h = icmp6_hdr(skb);
480 u8 type;
481
482 type = icmp6h->icmp6_type;
483
484 if (!dst) {
485 struct flowi6 fl6;
486 int oif = skb->dev->ifindex;
487
488 icmpv6_flow_init(sk, &fl6, type, saddr, daddr, oif);
489 dst = icmp6_dst_alloc(skb->dev, &fl6);
490 if (IS_ERR(dst)) {
491 kfree_skb(skb);
492 return;
493 }
494
495 skb_dst_set(skb, dst);
496 }
497
498 icmp6h->icmp6_cksum = csum_ipv6_magic(saddr, daddr, skb->len,
499 IPPROTO_ICMPV6,
500 csum_partial(icmp6h,
501 skb->len, 0));
502
503 ip6_nd_hdr(skb, saddr, daddr, inet6_sk(sk)->hop_limit, skb->len);
504
505 rcu_read_lock();
506 idev = __in6_dev_get(dst->dev);
507 IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);
508
509 err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
510 net, sk, skb, NULL, dst->dev,
511 dst_output);
512 if (!err) {
513 ICMP6MSGOUT_INC_STATS(net, idev, type);
514 ICMP6_INC_STATS(net, idev, ICMP6_MIB_OUTMSGS);
515 }
516
517 rcu_read_unlock();
518 }
519 EXPORT_SYMBOL(ndisc_send_skb);
520
ndisc_send_na(struct net_device * dev,const struct in6_addr * daddr,const struct in6_addr * solicited_addr,bool router,bool solicited,bool override,bool inc_opt)521 void ndisc_send_na(struct net_device *dev, const struct in6_addr *daddr,
522 const struct in6_addr *solicited_addr,
523 bool router, bool solicited, bool override, bool inc_opt)
524 {
525 struct sk_buff *skb;
526 struct in6_addr tmpaddr;
527 struct inet6_ifaddr *ifp;
528 const struct in6_addr *src_addr;
529 struct nd_msg *msg;
530 int optlen = 0;
531
532 /* for anycast or proxy, solicited_addr != src_addr */
533 ifp = ipv6_get_ifaddr(dev_net(dev), solicited_addr, dev, 1);
534 if (ifp) {
535 src_addr = solicited_addr;
536 if (ifp->flags & IFA_F_OPTIMISTIC)
537 override = false;
538 inc_opt |= ifp->idev->cnf.force_tllao;
539 in6_ifa_put(ifp);
540 } else {
541 if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
542 inet6_sk(dev_net(dev)->ipv6.ndisc_sk)->srcprefs,
543 &tmpaddr))
544 return;
545 src_addr = &tmpaddr;
546 }
547
548 if (!dev->addr_len)
549 inc_opt = false;
550 if (inc_opt)
551 optlen += ndisc_opt_addr_space(dev,
552 NDISC_NEIGHBOUR_ADVERTISEMENT);
553
554 skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
555 if (!skb)
556 return;
557
558 msg = skb_put(skb, sizeof(*msg));
559 *msg = (struct nd_msg) {
560 .icmph = {
561 .icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT,
562 .icmp6_router = router,
563 .icmp6_solicited = solicited,
564 .icmp6_override = override,
565 },
566 .target = *solicited_addr,
567 };
568
569 if (inc_opt)
570 ndisc_fill_addr_option(skb, ND_OPT_TARGET_LL_ADDR,
571 dev->dev_addr,
572 NDISC_NEIGHBOUR_ADVERTISEMENT);
573
574 ndisc_send_skb(skb, daddr, src_addr);
575 }
576
ndisc_send_unsol_na(struct net_device * dev)577 static void ndisc_send_unsol_na(struct net_device *dev)
578 {
579 struct inet6_dev *idev;
580 struct inet6_ifaddr *ifa;
581
582 idev = in6_dev_get(dev);
583 if (!idev)
584 return;
585
586 read_lock_bh(&idev->lock);
587 list_for_each_entry(ifa, &idev->addr_list, if_list) {
588 /* skip tentative addresses until dad completes */
589 if (ifa->flags & IFA_F_TENTATIVE &&
590 !(ifa->flags & IFA_F_OPTIMISTIC))
591 continue;
592
593 ndisc_send_na(dev, &in6addr_linklocal_allnodes, &ifa->addr,
594 /*router=*/ !!idev->cnf.forwarding,
595 /*solicited=*/ false, /*override=*/ true,
596 /*inc_opt=*/ true);
597 }
598 read_unlock_bh(&idev->lock);
599
600 in6_dev_put(idev);
601 }
602
ndisc_ns_create(struct net_device * dev,const struct in6_addr * solicit,const struct in6_addr * saddr,u64 nonce)603 struct sk_buff *ndisc_ns_create(struct net_device *dev, const struct in6_addr *solicit,
604 const struct in6_addr *saddr, u64 nonce)
605 {
606 int inc_opt = dev->addr_len;
607 struct sk_buff *skb;
608 struct nd_msg *msg;
609 int optlen = 0;
610
611 if (!saddr)
612 return NULL;
613
614 if (ipv6_addr_any(saddr))
615 inc_opt = false;
616 if (inc_opt)
617 optlen += ndisc_opt_addr_space(dev,
618 NDISC_NEIGHBOUR_SOLICITATION);
619 if (nonce != 0)
620 optlen += 8;
621
622 skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
623 if (!skb)
624 return NULL;
625
626 msg = skb_put(skb, sizeof(*msg));
627 *msg = (struct nd_msg) {
628 .icmph = {
629 .icmp6_type = NDISC_NEIGHBOUR_SOLICITATION,
630 },
631 .target = *solicit,
632 };
633
634 if (inc_opt)
635 ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
636 dev->dev_addr,
637 NDISC_NEIGHBOUR_SOLICITATION);
638 if (nonce != 0) {
639 u8 *opt = skb_put(skb, 8);
640
641 opt[0] = ND_OPT_NONCE;
642 opt[1] = 8 >> 3;
643 memcpy(opt + 2, &nonce, 6);
644 }
645
646 return skb;
647 }
648 EXPORT_SYMBOL(ndisc_ns_create);
649
ndisc_send_ns(struct net_device * dev,const struct in6_addr * solicit,const struct in6_addr * daddr,const struct in6_addr * saddr,u64 nonce)650 void ndisc_send_ns(struct net_device *dev, const struct in6_addr *solicit,
651 const struct in6_addr *daddr, const struct in6_addr *saddr,
652 u64 nonce)
653 {
654 struct in6_addr addr_buf;
655 struct sk_buff *skb;
656
657 if (!saddr) {
658 if (ipv6_get_lladdr(dev, &addr_buf,
659 (IFA_F_TENTATIVE | IFA_F_OPTIMISTIC)))
660 return;
661 saddr = &addr_buf;
662 }
663
664 skb = ndisc_ns_create(dev, solicit, saddr, nonce);
665
666 if (skb)
667 ndisc_send_skb(skb, daddr, saddr);
668 }
669
ndisc_send_rs(struct net_device * dev,const struct in6_addr * saddr,const struct in6_addr * daddr)670 void ndisc_send_rs(struct net_device *dev, const struct in6_addr *saddr,
671 const struct in6_addr *daddr)
672 {
673 struct sk_buff *skb;
674 struct rs_msg *msg;
675 int send_sllao = dev->addr_len;
676 int optlen = 0;
677
678 #ifdef CONFIG_IPV6_OPTIMISTIC_DAD
679 /*
680 * According to section 2.2 of RFC 4429, we must not
681 * send router solicitations with a sllao from
682 * optimistic addresses, but we may send the solicitation
683 * if we don't include the sllao. So here we check
684 * if our address is optimistic, and if so, we
685 * suppress the inclusion of the sllao.
686 */
687 if (send_sllao) {
688 struct inet6_ifaddr *ifp = ipv6_get_ifaddr(dev_net(dev), saddr,
689 dev, 1);
690 if (ifp) {
691 if (ifp->flags & IFA_F_OPTIMISTIC) {
692 send_sllao = 0;
693 }
694 in6_ifa_put(ifp);
695 } else {
696 send_sllao = 0;
697 }
698 }
699 #endif
700 if (send_sllao)
701 optlen += ndisc_opt_addr_space(dev, NDISC_ROUTER_SOLICITATION);
702
703 skb = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
704 if (!skb)
705 return;
706
707 msg = skb_put(skb, sizeof(*msg));
708 *msg = (struct rs_msg) {
709 .icmph = {
710 .icmp6_type = NDISC_ROUTER_SOLICITATION,
711 },
712 };
713
714 if (send_sllao)
715 ndisc_fill_addr_option(skb, ND_OPT_SOURCE_LL_ADDR,
716 dev->dev_addr,
717 NDISC_ROUTER_SOLICITATION);
718
719 ndisc_send_skb(skb, daddr, saddr);
720 }
721
722
ndisc_error_report(struct neighbour * neigh,struct sk_buff * skb)723 static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb)
724 {
725 /*
726 * "The sender MUST return an ICMP
727 * destination unreachable"
728 */
729 dst_link_failure(skb);
730 kfree_skb(skb);
731 }
732
733 /* Called with locked neigh: either read or both */
734
ndisc_solicit(struct neighbour * neigh,struct sk_buff * skb)735 static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
736 {
737 struct in6_addr *saddr = NULL;
738 struct in6_addr mcaddr;
739 struct net_device *dev = neigh->dev;
740 struct in6_addr *target = (struct in6_addr *)&neigh->primary_key;
741 int probes = atomic_read(&neigh->probes);
742
743 if (skb && ipv6_chk_addr_and_flags(dev_net(dev), &ipv6_hdr(skb)->saddr,
744 dev, false, 1,
745 IFA_F_TENTATIVE|IFA_F_OPTIMISTIC))
746 saddr = &ipv6_hdr(skb)->saddr;
747 probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
748 if (probes < 0) {
749 if (!(READ_ONCE(neigh->nud_state) & NUD_VALID)) {
750 ND_PRINTK(1, dbg,
751 "%s: trying to ucast probe in NUD_INVALID: %pI6\n",
752 __func__, target);
753 }
754 ndisc_send_ns(dev, target, target, saddr, 0);
755 } else if ((probes -= NEIGH_VAR(neigh->parms, APP_PROBES)) < 0) {
756 neigh_app_ns(neigh);
757 } else {
758 addrconf_addr_solict_mult(target, &mcaddr);
759 ndisc_send_ns(dev, target, &mcaddr, saddr, 0);
760 }
761 }
762
pndisc_is_router(const void * pkey,struct net_device * dev)763 static int pndisc_is_router(const void *pkey,
764 struct net_device *dev)
765 {
766 struct pneigh_entry *n;
767 int ret = -1;
768
769 read_lock_bh(&nd_tbl.lock);
770 n = __pneigh_lookup(&nd_tbl, dev_net(dev), pkey, dev);
771 if (n)
772 ret = !!(n->flags & NTF_ROUTER);
773 read_unlock_bh(&nd_tbl.lock);
774
775 return ret;
776 }
777
ndisc_update(const struct net_device * dev,struct neighbour * neigh,const u8 * lladdr,u8 new,u32 flags,u8 icmp6_type,struct ndisc_options * ndopts)778 void ndisc_update(const struct net_device *dev, struct neighbour *neigh,
779 const u8 *lladdr, u8 new, u32 flags, u8 icmp6_type,
780 struct ndisc_options *ndopts)
781 {
782 neigh_update(neigh, lladdr, new, flags, 0);
783 /* report ndisc ops about neighbour update */
784 ndisc_ops_update(dev, neigh, flags, icmp6_type, ndopts);
785 }
786
ndisc_recv_ns(struct sk_buff * skb)787 static enum skb_drop_reason ndisc_recv_ns(struct sk_buff *skb)
788 {
789 struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
790 const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
791 const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
792 u8 *lladdr = NULL;
793 u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
794 offsetof(struct nd_msg, opt));
795 struct ndisc_options ndopts;
796 struct net_device *dev = skb->dev;
797 struct inet6_ifaddr *ifp;
798 struct inet6_dev *idev = NULL;
799 struct neighbour *neigh;
800 int dad = ipv6_addr_any(saddr);
801 int is_router = -1;
802 SKB_DR(reason);
803 u64 nonce = 0;
804 bool inc;
805
806 if (skb->len < sizeof(struct nd_msg))
807 return SKB_DROP_REASON_PKT_TOO_SMALL;
808
809 if (ipv6_addr_is_multicast(&msg->target)) {
810 ND_PRINTK(2, warn, "NS: multicast target address\n");
811 return reason;
812 }
813
814 /*
815 * RFC2461 7.1.1:
816 * DAD has to be destined for solicited node multicast address.
817 */
818 if (dad && !ipv6_addr_is_solict_mult(daddr)) {
819 ND_PRINTK(2, warn, "NS: bad DAD packet (wrong destination)\n");
820 return reason;
821 }
822
823 if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts))
824 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
825
826 if (ndopts.nd_opts_src_lladdr) {
827 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr, dev);
828 if (!lladdr) {
829 ND_PRINTK(2, warn,
830 "NS: invalid link-layer address length\n");
831 return reason;
832 }
833
834 /* RFC2461 7.1.1:
835 * If the IP source address is the unspecified address,
836 * there MUST NOT be source link-layer address option
837 * in the message.
838 */
839 if (dad) {
840 ND_PRINTK(2, warn,
841 "NS: bad DAD packet (link-layer address option)\n");
842 return reason;
843 }
844 }
845 if (ndopts.nd_opts_nonce && ndopts.nd_opts_nonce->nd_opt_len == 1)
846 memcpy(&nonce, (u8 *)(ndopts.nd_opts_nonce + 1), 6);
847
848 inc = ipv6_addr_is_multicast(daddr);
849
850 ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
851 if (ifp) {
852 have_ifp:
853 if (ifp->flags & (IFA_F_TENTATIVE|IFA_F_OPTIMISTIC)) {
854 if (dad) {
855 if (nonce != 0 && ifp->dad_nonce == nonce) {
856 u8 *np = (u8 *)&nonce;
857 /* Matching nonce if looped back */
858 ND_PRINTK(2, notice,
859 "%s: IPv6 DAD loopback for address %pI6c nonce %pM ignored\n",
860 ifp->idev->dev->name,
861 &ifp->addr, np);
862 goto out;
863 }
864 /*
865 * We are colliding with another node
866 * who is doing DAD
867 * so fail our DAD process
868 */
869 addrconf_dad_failure(skb, ifp);
870 return reason;
871 } else {
872 /*
873 * This is not a dad solicitation.
874 * If we are an optimistic node,
875 * we should respond.
876 * Otherwise, we should ignore it.
877 */
878 if (!(ifp->flags & IFA_F_OPTIMISTIC))
879 goto out;
880 }
881 }
882
883 idev = ifp->idev;
884 } else {
885 struct net *net = dev_net(dev);
886
887 /* perhaps an address on the master device */
888 if (netif_is_l3_slave(dev)) {
889 struct net_device *mdev;
890
891 mdev = netdev_master_upper_dev_get_rcu(dev);
892 if (mdev) {
893 ifp = ipv6_get_ifaddr(net, &msg->target, mdev, 1);
894 if (ifp)
895 goto have_ifp;
896 }
897 }
898
899 idev = in6_dev_get(dev);
900 if (!idev) {
901 /* XXX: count this drop? */
902 return reason;
903 }
904
905 if (ipv6_chk_acast_addr(net, dev, &msg->target) ||
906 (idev->cnf.forwarding &&
907 (net->ipv6.devconf_all->proxy_ndp || idev->cnf.proxy_ndp) &&
908 (is_router = pndisc_is_router(&msg->target, dev)) >= 0)) {
909 if (!(NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED) &&
910 skb->pkt_type != PACKET_HOST &&
911 inc &&
912 NEIGH_VAR(idev->nd_parms, PROXY_DELAY) != 0) {
913 /*
914 * for anycast or proxy,
915 * sender should delay its response
916 * by a random time between 0 and
917 * MAX_ANYCAST_DELAY_TIME seconds.
918 * (RFC2461) -- yoshfuji
919 */
920 struct sk_buff *n = skb_clone(skb, GFP_ATOMIC);
921 if (n)
922 pneigh_enqueue(&nd_tbl, idev->nd_parms, n);
923 goto out;
924 }
925 } else {
926 SKB_DR_SET(reason, IPV6_NDISC_NS_OTHERHOST);
927 goto out;
928 }
929 }
930
931 if (is_router < 0)
932 is_router = idev->cnf.forwarding;
933
934 if (dad) {
935 ndisc_send_na(dev, &in6addr_linklocal_allnodes, &msg->target,
936 !!is_router, false, (ifp != NULL), true);
937 goto out;
938 }
939
940 if (inc)
941 NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_mcast);
942 else
943 NEIGH_CACHE_STAT_INC(&nd_tbl, rcv_probes_ucast);
944
945 /*
946 * update / create cache entry
947 * for the source address
948 */
949 neigh = __neigh_lookup(&nd_tbl, saddr, dev,
950 !inc || lladdr || !dev->addr_len);
951 if (neigh)
952 ndisc_update(dev, neigh, lladdr, NUD_STALE,
953 NEIGH_UPDATE_F_WEAK_OVERRIDE|
954 NEIGH_UPDATE_F_OVERRIDE,
955 NDISC_NEIGHBOUR_SOLICITATION, &ndopts);
956 if (neigh || !dev->header_ops) {
957 ndisc_send_na(dev, saddr, &msg->target, !!is_router,
958 true, (ifp != NULL && inc), inc);
959 if (neigh)
960 neigh_release(neigh);
961 reason = SKB_CONSUMED;
962 }
963
964 out:
965 if (ifp)
966 in6_ifa_put(ifp);
967 else
968 in6_dev_put(idev);
969 return reason;
970 }
971
accept_untracked_na(struct net_device * dev,struct in6_addr * saddr)972 static int accept_untracked_na(struct net_device *dev, struct in6_addr *saddr)
973 {
974 struct inet6_dev *idev = __in6_dev_get(dev);
975
976 switch (idev->cnf.accept_untracked_na) {
977 case 0: /* Don't accept untracked na (absent in neighbor cache) */
978 return 0;
979 case 1: /* Create new entries from na if currently untracked */
980 return 1;
981 case 2: /* Create new entries from untracked na only if saddr is in the
982 * same subnet as an address configured on the interface that
983 * received the na
984 */
985 return !!ipv6_chk_prefix(saddr, dev);
986 default:
987 return 0;
988 }
989 }
990
ndisc_recv_na(struct sk_buff * skb)991 static enum skb_drop_reason ndisc_recv_na(struct sk_buff *skb)
992 {
993 struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
994 struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
995 const struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
996 u8 *lladdr = NULL;
997 u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
998 offsetof(struct nd_msg, opt));
999 struct ndisc_options ndopts;
1000 struct net_device *dev = skb->dev;
1001 struct inet6_dev *idev = __in6_dev_get(dev);
1002 struct inet6_ifaddr *ifp;
1003 struct neighbour *neigh;
1004 SKB_DR(reason);
1005 u8 new_state;
1006
1007 if (skb->len < sizeof(struct nd_msg))
1008 return SKB_DROP_REASON_PKT_TOO_SMALL;
1009
1010 if (ipv6_addr_is_multicast(&msg->target)) {
1011 ND_PRINTK(2, warn, "NA: target address is multicast\n");
1012 return reason;
1013 }
1014
1015 if (ipv6_addr_is_multicast(daddr) &&
1016 msg->icmph.icmp6_solicited) {
1017 ND_PRINTK(2, warn, "NA: solicited NA is multicasted\n");
1018 return reason;
1019 }
1020
1021 /* For some 802.11 wireless deployments (and possibly other networks),
1022 * there will be a NA proxy and unsolicitd packets are attacks
1023 * and thus should not be accepted.
1024 * drop_unsolicited_na takes precedence over accept_untracked_na
1025 */
1026 if (!msg->icmph.icmp6_solicited && idev &&
1027 idev->cnf.drop_unsolicited_na)
1028 return reason;
1029
1030 if (!ndisc_parse_options(dev, msg->opt, ndoptlen, &ndopts))
1031 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1032
1033 if (ndopts.nd_opts_tgt_lladdr) {
1034 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_tgt_lladdr, dev);
1035 if (!lladdr) {
1036 ND_PRINTK(2, warn,
1037 "NA: invalid link-layer address length\n");
1038 return reason;
1039 }
1040 }
1041 ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
1042 if (ifp) {
1043 if (skb->pkt_type != PACKET_LOOPBACK
1044 && (ifp->flags & IFA_F_TENTATIVE)) {
1045 addrconf_dad_failure(skb, ifp);
1046 return reason;
1047 }
1048 /* What should we make now? The advertisement
1049 is invalid, but ndisc specs say nothing
1050 about it. It could be misconfiguration, or
1051 an smart proxy agent tries to help us :-)
1052
1053 We should not print the error if NA has been
1054 received from loopback - it is just our own
1055 unsolicited advertisement.
1056 */
1057 if (skb->pkt_type != PACKET_LOOPBACK)
1058 ND_PRINTK(1, warn,
1059 "NA: %pM advertised our address %pI6c on %s!\n",
1060 eth_hdr(skb)->h_source, &ifp->addr, ifp->idev->dev->name);
1061 in6_ifa_put(ifp);
1062 return reason;
1063 }
1064
1065 neigh = neigh_lookup(&nd_tbl, &msg->target, dev);
1066
1067 /* RFC 9131 updates original Neighbour Discovery RFC 4861.
1068 * NAs with Target LL Address option without a corresponding
1069 * entry in the neighbour cache can now create a STALE neighbour
1070 * cache entry on routers.
1071 *
1072 * entry accept fwding solicited behaviour
1073 * ------- ------ ------ --------- ----------------------
1074 * present X X 0 Set state to STALE
1075 * present X X 1 Set state to REACHABLE
1076 * absent 0 X X Do nothing
1077 * absent 1 0 X Do nothing
1078 * absent 1 1 X Add a new STALE entry
1079 *
1080 * Note that we don't do a (daddr == all-routers-mcast) check.
1081 */
1082 new_state = msg->icmph.icmp6_solicited ? NUD_REACHABLE : NUD_STALE;
1083 if (!neigh && lladdr && idev && idev->cnf.forwarding) {
1084 if (accept_untracked_na(dev, saddr)) {
1085 neigh = neigh_create(&nd_tbl, &msg->target, dev);
1086 new_state = NUD_STALE;
1087 }
1088 }
1089
1090 if (neigh && !IS_ERR(neigh)) {
1091 u8 old_flags = neigh->flags;
1092 struct net *net = dev_net(dev);
1093
1094 if (READ_ONCE(neigh->nud_state) & NUD_FAILED)
1095 goto out;
1096
1097 /*
1098 * Don't update the neighbor cache entry on a proxy NA from
1099 * ourselves because either the proxied node is off link or it
1100 * has already sent a NA to us.
1101 */
1102 if (lladdr && !memcmp(lladdr, dev->dev_addr, dev->addr_len) &&
1103 net->ipv6.devconf_all->forwarding && net->ipv6.devconf_all->proxy_ndp &&
1104 pneigh_lookup(&nd_tbl, net, &msg->target, dev, 0)) {
1105 /* XXX: idev->cnf.proxy_ndp */
1106 goto out;
1107 }
1108
1109 ndisc_update(dev, neigh, lladdr,
1110 new_state,
1111 NEIGH_UPDATE_F_WEAK_OVERRIDE|
1112 (msg->icmph.icmp6_override ? NEIGH_UPDATE_F_OVERRIDE : 0)|
1113 NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1114 (msg->icmph.icmp6_router ? NEIGH_UPDATE_F_ISROUTER : 0),
1115 NDISC_NEIGHBOUR_ADVERTISEMENT, &ndopts);
1116
1117 if ((old_flags & ~neigh->flags) & NTF_ROUTER) {
1118 /*
1119 * Change: router to host
1120 */
1121 rt6_clean_tohost(dev_net(dev), saddr);
1122 }
1123 reason = SKB_CONSUMED;
1124 out:
1125 neigh_release(neigh);
1126 }
1127 return reason;
1128 }
1129
ndisc_recv_rs(struct sk_buff * skb)1130 static enum skb_drop_reason ndisc_recv_rs(struct sk_buff *skb)
1131 {
1132 struct rs_msg *rs_msg = (struct rs_msg *)skb_transport_header(skb);
1133 unsigned long ndoptlen = skb->len - sizeof(*rs_msg);
1134 struct neighbour *neigh;
1135 struct inet6_dev *idev;
1136 const struct in6_addr *saddr = &ipv6_hdr(skb)->saddr;
1137 struct ndisc_options ndopts;
1138 u8 *lladdr = NULL;
1139 SKB_DR(reason);
1140
1141 if (skb->len < sizeof(*rs_msg))
1142 return SKB_DROP_REASON_PKT_TOO_SMALL;
1143
1144 idev = __in6_dev_get(skb->dev);
1145 if (!idev) {
1146 ND_PRINTK(1, err, "RS: can't find in6 device\n");
1147 return reason;
1148 }
1149
1150 /* Don't accept RS if we're not in router mode */
1151 if (!idev->cnf.forwarding)
1152 goto out;
1153
1154 /*
1155 * Don't update NCE if src = ::;
1156 * this implies that the source node has no ip address assigned yet.
1157 */
1158 if (ipv6_addr_any(saddr))
1159 goto out;
1160
1161 /* Parse ND options */
1162 if (!ndisc_parse_options(skb->dev, rs_msg->opt, ndoptlen, &ndopts))
1163 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1164
1165 if (ndopts.nd_opts_src_lladdr) {
1166 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1167 skb->dev);
1168 if (!lladdr)
1169 goto out;
1170 }
1171
1172 neigh = __neigh_lookup(&nd_tbl, saddr, skb->dev, 1);
1173 if (neigh) {
1174 ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1175 NEIGH_UPDATE_F_WEAK_OVERRIDE|
1176 NEIGH_UPDATE_F_OVERRIDE|
1177 NEIGH_UPDATE_F_OVERRIDE_ISROUTER,
1178 NDISC_ROUTER_SOLICITATION, &ndopts);
1179 neigh_release(neigh);
1180 reason = SKB_CONSUMED;
1181 }
1182 out:
1183 return reason;
1184 }
1185
ndisc_ra_useropt(struct sk_buff * ra,struct nd_opt_hdr * opt)1186 static void ndisc_ra_useropt(struct sk_buff *ra, struct nd_opt_hdr *opt)
1187 {
1188 struct icmp6hdr *icmp6h = (struct icmp6hdr *)skb_transport_header(ra);
1189 struct sk_buff *skb;
1190 struct nlmsghdr *nlh;
1191 struct nduseroptmsg *ndmsg;
1192 struct net *net = dev_net(ra->dev);
1193 int err;
1194 int base_size = NLMSG_ALIGN(sizeof(struct nduseroptmsg)
1195 + (opt->nd_opt_len << 3));
1196 size_t msg_size = base_size + nla_total_size(sizeof(struct in6_addr));
1197
1198 skb = nlmsg_new(msg_size, GFP_ATOMIC);
1199 if (!skb) {
1200 err = -ENOBUFS;
1201 goto errout;
1202 }
1203
1204 nlh = nlmsg_put(skb, 0, 0, RTM_NEWNDUSEROPT, base_size, 0);
1205 if (!nlh) {
1206 goto nla_put_failure;
1207 }
1208
1209 ndmsg = nlmsg_data(nlh);
1210 ndmsg->nduseropt_family = AF_INET6;
1211 ndmsg->nduseropt_ifindex = ra->dev->ifindex;
1212 ndmsg->nduseropt_icmp_type = icmp6h->icmp6_type;
1213 ndmsg->nduseropt_icmp_code = icmp6h->icmp6_code;
1214 ndmsg->nduseropt_opts_len = opt->nd_opt_len << 3;
1215
1216 memcpy(ndmsg + 1, opt, opt->nd_opt_len << 3);
1217
1218 if (nla_put_in6_addr(skb, NDUSEROPT_SRCADDR, &ipv6_hdr(ra)->saddr))
1219 goto nla_put_failure;
1220 nlmsg_end(skb, nlh);
1221
1222 rtnl_notify(skb, net, 0, RTNLGRP_ND_USEROPT, NULL, GFP_ATOMIC);
1223 return;
1224
1225 nla_put_failure:
1226 nlmsg_free(skb);
1227 err = -EMSGSIZE;
1228 errout:
1229 rtnl_set_sk_err(net, RTNLGRP_ND_USEROPT, err);
1230 }
1231
ndisc_router_discovery(struct sk_buff * skb)1232 static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb)
1233 {
1234 struct ra_msg *ra_msg = (struct ra_msg *)skb_transport_header(skb);
1235 bool send_ifinfo_notify = false;
1236 struct neighbour *neigh = NULL;
1237 struct ndisc_options ndopts;
1238 struct fib6_info *rt = NULL;
1239 struct inet6_dev *in6_dev;
1240 u32 defrtr_usr_metric;
1241 unsigned int pref = 0;
1242 __u32 old_if_flags;
1243 struct net *net;
1244 SKB_DR(reason);
1245 int lifetime;
1246 int optlen;
1247
1248 __u8 *opt = (__u8 *)(ra_msg + 1);
1249
1250 optlen = (skb_tail_pointer(skb) - skb_transport_header(skb)) -
1251 sizeof(struct ra_msg);
1252
1253 ND_PRINTK(2, info,
1254 "RA: %s, dev: %s\n",
1255 __func__, skb->dev->name);
1256 if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1257 ND_PRINTK(2, warn, "RA: source address is not link-local\n");
1258 return reason;
1259 }
1260 if (optlen < 0)
1261 return SKB_DROP_REASON_PKT_TOO_SMALL;
1262
1263 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1264 if (skb->ndisc_nodetype == NDISC_NODETYPE_HOST) {
1265 ND_PRINTK(2, warn, "RA: from host or unauthorized router\n");
1266 return reason;
1267 }
1268 #endif
1269
1270 in6_dev = __in6_dev_get(skb->dev);
1271 if (!in6_dev) {
1272 ND_PRINTK(0, err, "RA: can't find inet6 device for %s\n",
1273 skb->dev->name);
1274 return reason;
1275 }
1276
1277 if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts))
1278 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1279
1280 if (!ipv6_accept_ra(in6_dev)) {
1281 ND_PRINTK(2, info,
1282 "RA: %s, did not accept ra for dev: %s\n",
1283 __func__, skb->dev->name);
1284 goto skip_linkparms;
1285 }
1286
1287 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1288 /* skip link-specific parameters from interior routers */
1289 if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1290 ND_PRINTK(2, info,
1291 "RA: %s, nodetype is NODEFAULT, dev: %s\n",
1292 __func__, skb->dev->name);
1293 goto skip_linkparms;
1294 }
1295 #endif
1296
1297 if (in6_dev->if_flags & IF_RS_SENT) {
1298 /*
1299 * flag that an RA was received after an RS was sent
1300 * out on this interface.
1301 */
1302 in6_dev->if_flags |= IF_RA_RCVD;
1303 }
1304
1305 /*
1306 * Remember the managed/otherconf flags from most recently
1307 * received RA message (RFC 2462) -- yoshfuji
1308 */
1309 old_if_flags = in6_dev->if_flags;
1310 in6_dev->if_flags = (in6_dev->if_flags & ~(IF_RA_MANAGED |
1311 IF_RA_OTHERCONF)) |
1312 (ra_msg->icmph.icmp6_addrconf_managed ?
1313 IF_RA_MANAGED : 0) |
1314 (ra_msg->icmph.icmp6_addrconf_other ?
1315 IF_RA_OTHERCONF : 0);
1316
1317 if (old_if_flags != in6_dev->if_flags)
1318 send_ifinfo_notify = true;
1319
1320 if (!in6_dev->cnf.accept_ra_defrtr) {
1321 ND_PRINTK(2, info,
1322 "RA: %s, defrtr is false for dev: %s\n",
1323 __func__, skb->dev->name);
1324 goto skip_defrtr;
1325 }
1326
1327 lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime);
1328 if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_lft) {
1329 ND_PRINTK(2, info,
1330 "RA: router lifetime (%ds) is too short: %s\n",
1331 lifetime, skb->dev->name);
1332 goto skip_defrtr;
1333 }
1334
1335 /* Do not accept RA with source-addr found on local machine unless
1336 * accept_ra_from_local is set to true.
1337 */
1338 net = dev_net(in6_dev->dev);
1339 if (!in6_dev->cnf.accept_ra_from_local &&
1340 ipv6_chk_addr(net, &ipv6_hdr(skb)->saddr, in6_dev->dev, 0)) {
1341 ND_PRINTK(2, info,
1342 "RA from local address detected on dev: %s: default router ignored\n",
1343 skb->dev->name);
1344 goto skip_defrtr;
1345 }
1346
1347 #ifdef CONFIG_IPV6_ROUTER_PREF
1348 pref = ra_msg->icmph.icmp6_router_pref;
1349 /* 10b is handled as if it were 00b (medium) */
1350 if (pref == ICMPV6_ROUTER_PREF_INVALID ||
1351 !in6_dev->cnf.accept_ra_rtr_pref)
1352 pref = ICMPV6_ROUTER_PREF_MEDIUM;
1353 #endif
1354 /* routes added from RAs do not use nexthop objects */
1355 rt = rt6_get_dflt_router(net, &ipv6_hdr(skb)->saddr, skb->dev);
1356 if (rt) {
1357 neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1358 rt->fib6_nh->fib_nh_dev, NULL,
1359 &ipv6_hdr(skb)->saddr);
1360 if (!neigh) {
1361 ND_PRINTK(0, err,
1362 "RA: %s got default router without neighbour\n",
1363 __func__);
1364 fib6_info_release(rt);
1365 return reason;
1366 }
1367 }
1368 /* Set default route metric as specified by user */
1369 defrtr_usr_metric = in6_dev->cnf.ra_defrtr_metric;
1370 /* delete the route if lifetime is 0 or if metric needs change */
1371 if (rt && (lifetime == 0 || rt->fib6_metric != defrtr_usr_metric)) {
1372 ip6_del_rt(net, rt, false);
1373 rt = NULL;
1374 }
1375
1376 ND_PRINTK(3, info, "RA: rt: %p lifetime: %d, metric: %d, for dev: %s\n",
1377 rt, lifetime, defrtr_usr_metric, skb->dev->name);
1378 if (!rt && lifetime) {
1379 ND_PRINTK(3, info, "RA: adding default router\n");
1380
1381 if (neigh)
1382 neigh_release(neigh);
1383
1384 rt = rt6_add_dflt_router(net, &ipv6_hdr(skb)->saddr,
1385 skb->dev, pref, defrtr_usr_metric);
1386 if (!rt) {
1387 ND_PRINTK(0, err,
1388 "RA: %s failed to add default route\n",
1389 __func__);
1390 return reason;
1391 }
1392
1393 neigh = ip6_neigh_lookup(&rt->fib6_nh->fib_nh_gw6,
1394 rt->fib6_nh->fib_nh_dev, NULL,
1395 &ipv6_hdr(skb)->saddr);
1396 if (!neigh) {
1397 ND_PRINTK(0, err,
1398 "RA: %s got default router without neighbour\n",
1399 __func__);
1400 fib6_info_release(rt);
1401 return reason;
1402 }
1403 neigh->flags |= NTF_ROUTER;
1404 } else if (rt && IPV6_EXTRACT_PREF(rt->fib6_flags) != pref) {
1405 struct nl_info nlinfo = {
1406 .nl_net = net,
1407 };
1408 rt->fib6_flags = (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
1409 inet6_rt_notify(RTM_NEWROUTE, rt, &nlinfo, NLM_F_REPLACE);
1410 }
1411
1412 if (rt)
1413 fib6_set_expires(rt, jiffies + (HZ * lifetime));
1414 if (in6_dev->cnf.accept_ra_min_hop_limit < 256 &&
1415 ra_msg->icmph.icmp6_hop_limit) {
1416 if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) {
1417 in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
1418 fib6_metric_set(rt, RTAX_HOPLIMIT,
1419 ra_msg->icmph.icmp6_hop_limit);
1420 } else {
1421 ND_PRINTK(2, warn, "RA: Got route advertisement with lower hop_limit than minimum\n");
1422 }
1423 }
1424
1425 skip_defrtr:
1426
1427 /*
1428 * Update Reachable Time and Retrans Timer
1429 */
1430
1431 if (in6_dev->nd_parms) {
1432 unsigned long rtime = ntohl(ra_msg->retrans_timer);
1433
1434 if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) {
1435 rtime = (rtime*HZ)/1000;
1436 if (rtime < HZ/100)
1437 rtime = HZ/100;
1438 NEIGH_VAR_SET(in6_dev->nd_parms, RETRANS_TIME, rtime);
1439 in6_dev->tstamp = jiffies;
1440 send_ifinfo_notify = true;
1441 }
1442
1443 rtime = ntohl(ra_msg->reachable_time);
1444 if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
1445 rtime = (rtime*HZ)/1000;
1446
1447 if (rtime < HZ/10)
1448 rtime = HZ/10;
1449
1450 if (rtime != NEIGH_VAR(in6_dev->nd_parms, BASE_REACHABLE_TIME)) {
1451 NEIGH_VAR_SET(in6_dev->nd_parms,
1452 BASE_REACHABLE_TIME, rtime);
1453 NEIGH_VAR_SET(in6_dev->nd_parms,
1454 GC_STALETIME, 3 * rtime);
1455 in6_dev->nd_parms->reachable_time = neigh_rand_reach_time(rtime);
1456 in6_dev->tstamp = jiffies;
1457 send_ifinfo_notify = true;
1458 }
1459 }
1460 }
1461
1462 skip_linkparms:
1463
1464 /*
1465 * Process options.
1466 */
1467
1468 if (!neigh)
1469 neigh = __neigh_lookup(&nd_tbl, &ipv6_hdr(skb)->saddr,
1470 skb->dev, 1);
1471 if (neigh) {
1472 u8 *lladdr = NULL;
1473 if (ndopts.nd_opts_src_lladdr) {
1474 lladdr = ndisc_opt_addr_data(ndopts.nd_opts_src_lladdr,
1475 skb->dev);
1476 if (!lladdr) {
1477 ND_PRINTK(2, warn,
1478 "RA: invalid link-layer address length\n");
1479 goto out;
1480 }
1481 }
1482 ndisc_update(skb->dev, neigh, lladdr, NUD_STALE,
1483 NEIGH_UPDATE_F_WEAK_OVERRIDE|
1484 NEIGH_UPDATE_F_OVERRIDE|
1485 NEIGH_UPDATE_F_OVERRIDE_ISROUTER|
1486 NEIGH_UPDATE_F_ISROUTER,
1487 NDISC_ROUTER_ADVERTISEMENT, &ndopts);
1488 reason = SKB_CONSUMED;
1489 }
1490
1491 if (!ipv6_accept_ra(in6_dev)) {
1492 ND_PRINTK(2, info,
1493 "RA: %s, accept_ra is false for dev: %s\n",
1494 __func__, skb->dev->name);
1495 goto out;
1496 }
1497
1498 #ifdef CONFIG_IPV6_ROUTE_INFO
1499 if (!in6_dev->cnf.accept_ra_from_local &&
1500 ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr,
1501 in6_dev->dev, 0)) {
1502 ND_PRINTK(2, info,
1503 "RA from local address detected on dev: %s: router info ignored.\n",
1504 skb->dev->name);
1505 goto skip_routeinfo;
1506 }
1507
1508 if (in6_dev->cnf.accept_ra_rtr_pref && ndopts.nd_opts_ri) {
1509 struct nd_opt_hdr *p;
1510 for (p = ndopts.nd_opts_ri;
1511 p;
1512 p = ndisc_next_option(p, ndopts.nd_opts_ri_end)) {
1513 struct route_info *ri = (struct route_info *)p;
1514 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1515 if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT &&
1516 ri->prefix_len == 0)
1517 continue;
1518 #endif
1519 if (ri->prefix_len == 0 &&
1520 !in6_dev->cnf.accept_ra_defrtr)
1521 continue;
1522 if (ri->lifetime != 0 &&
1523 ntohl(ri->lifetime) < in6_dev->cnf.accept_ra_min_lft)
1524 continue;
1525 if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen)
1526 continue;
1527 if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)
1528 continue;
1529 rt6_route_rcv(skb->dev, (u8 *)p, (p->nd_opt_len) << 3,
1530 &ipv6_hdr(skb)->saddr);
1531 }
1532 }
1533
1534 skip_routeinfo:
1535 #endif
1536
1537 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1538 /* skip link-specific ndopts from interior routers */
1539 if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) {
1540 ND_PRINTK(2, info,
1541 "RA: %s, nodetype is NODEFAULT (interior routes), dev: %s\n",
1542 __func__, skb->dev->name);
1543 goto out;
1544 }
1545 #endif
1546
1547 if (in6_dev->cnf.accept_ra_pinfo && ndopts.nd_opts_pi) {
1548 struct nd_opt_hdr *p;
1549 for (p = ndopts.nd_opts_pi;
1550 p;
1551 p = ndisc_next_option(p, ndopts.nd_opts_pi_end)) {
1552 addrconf_prefix_rcv(skb->dev, (u8 *)p,
1553 (p->nd_opt_len) << 3,
1554 ndopts.nd_opts_src_lladdr != NULL);
1555 }
1556 }
1557
1558 if (ndopts.nd_opts_mtu && in6_dev->cnf.accept_ra_mtu) {
1559 __be32 n;
1560 u32 mtu;
1561
1562 memcpy(&n, ((u8 *)(ndopts.nd_opts_mtu+1))+2, sizeof(mtu));
1563 mtu = ntohl(n);
1564
1565 if (in6_dev->ra_mtu != mtu) {
1566 in6_dev->ra_mtu = mtu;
1567 send_ifinfo_notify = true;
1568 }
1569
1570 if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {
1571 ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);
1572 } else if (in6_dev->cnf.mtu6 != mtu) {
1573 in6_dev->cnf.mtu6 = mtu;
1574 fib6_metric_set(rt, RTAX_MTU, mtu);
1575 rt6_mtu_change(skb->dev, mtu);
1576 }
1577 }
1578
1579 if (ndopts.nd_useropts) {
1580 struct nd_opt_hdr *p;
1581 for (p = ndopts.nd_useropts;
1582 p;
1583 p = ndisc_next_useropt(skb->dev, p,
1584 ndopts.nd_useropts_end)) {
1585 ndisc_ra_useropt(skb, p);
1586 }
1587 }
1588
1589 if (ndopts.nd_opts_tgt_lladdr || ndopts.nd_opts_rh) {
1590 ND_PRINTK(2, warn, "RA: invalid RA options\n");
1591 }
1592 out:
1593 /* Send a notify if RA changed managed/otherconf flags or
1594 * timer settings or ra_mtu value
1595 */
1596 if (send_ifinfo_notify)
1597 inet6_ifinfo_notify(RTM_NEWLINK, in6_dev);
1598
1599 fib6_info_release(rt);
1600 if (neigh)
1601 neigh_release(neigh);
1602 return reason;
1603 }
1604
ndisc_redirect_rcv(struct sk_buff * skb)1605 static enum skb_drop_reason ndisc_redirect_rcv(struct sk_buff *skb)
1606 {
1607 struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb);
1608 u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
1609 offsetof(struct rd_msg, opt));
1610 struct ndisc_options ndopts;
1611 SKB_DR(reason);
1612 u8 *hdr;
1613
1614 #ifdef CONFIG_IPV6_NDISC_NODETYPE
1615 switch (skb->ndisc_nodetype) {
1616 case NDISC_NODETYPE_HOST:
1617 case NDISC_NODETYPE_NODEFAULT:
1618 ND_PRINTK(2, warn,
1619 "Redirect: from host or unauthorized router\n");
1620 return reason;
1621 }
1622 #endif
1623
1624 if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
1625 ND_PRINTK(2, warn,
1626 "Redirect: source address is not link-local\n");
1627 return reason;
1628 }
1629
1630 if (!ndisc_parse_options(skb->dev, msg->opt, ndoptlen, &ndopts))
1631 return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
1632
1633 if (!ndopts.nd_opts_rh) {
1634 ip6_redirect_no_header(skb, dev_net(skb->dev),
1635 skb->dev->ifindex);
1636 return reason;
1637 }
1638
1639 hdr = (u8 *)ndopts.nd_opts_rh;
1640 hdr += 8;
1641 if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
1642 return SKB_DROP_REASON_PKT_TOO_SMALL;
1643
1644 return icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
1645 }
1646
ndisc_fill_redirect_hdr_option(struct sk_buff * skb,struct sk_buff * orig_skb,int rd_len)1647 static void ndisc_fill_redirect_hdr_option(struct sk_buff *skb,
1648 struct sk_buff *orig_skb,
1649 int rd_len)
1650 {
1651 u8 *opt = skb_put(skb, rd_len);
1652
1653 memset(opt, 0, 8);
1654 *(opt++) = ND_OPT_REDIRECT_HDR;
1655 *(opt++) = (rd_len >> 3);
1656 opt += 6;
1657
1658 skb_copy_bits(orig_skb, skb_network_offset(orig_skb), opt,
1659 rd_len - 8);
1660 }
1661
ndisc_send_redirect(struct sk_buff * skb,const struct in6_addr * target)1662 void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
1663 {
1664 struct net_device *dev = skb->dev;
1665 struct net *net = dev_net(dev);
1666 struct sock *sk = net->ipv6.ndisc_sk;
1667 int optlen = 0;
1668 struct inet_peer *peer;
1669 struct sk_buff *buff;
1670 struct rd_msg *msg;
1671 struct in6_addr saddr_buf;
1672 struct rt6_info *rt;
1673 struct dst_entry *dst;
1674 struct flowi6 fl6;
1675 int rd_len;
1676 u8 ha_buf[MAX_ADDR_LEN], *ha = NULL,
1677 ops_data_buf[NDISC_OPS_REDIRECT_DATA_SPACE], *ops_data = NULL;
1678 bool ret;
1679
1680 if (netif_is_l3_master(skb->dev)) {
1681 dev = __dev_get_by_index(dev_net(skb->dev), IPCB(skb)->iif);
1682 if (!dev)
1683 return;
1684 }
1685
1686 if (ipv6_get_lladdr(dev, &saddr_buf, IFA_F_TENTATIVE)) {
1687 ND_PRINTK(2, warn, "Redirect: no link-local address on %s\n",
1688 dev->name);
1689 return;
1690 }
1691
1692 if (!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, target) &&
1693 ipv6_addr_type(target) != (IPV6_ADDR_UNICAST|IPV6_ADDR_LINKLOCAL)) {
1694 ND_PRINTK(2, warn,
1695 "Redirect: target address is not link-local unicast\n");
1696 return;
1697 }
1698
1699 icmpv6_flow_init(sk, &fl6, NDISC_REDIRECT,
1700 &saddr_buf, &ipv6_hdr(skb)->saddr, dev->ifindex);
1701
1702 dst = ip6_route_output(net, NULL, &fl6);
1703 if (dst->error) {
1704 dst_release(dst);
1705 return;
1706 }
1707 dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
1708 if (IS_ERR(dst))
1709 return;
1710
1711 rt = (struct rt6_info *) dst;
1712
1713 if (rt->rt6i_flags & RTF_GATEWAY) {
1714 ND_PRINTK(2, warn,
1715 "Redirect: destination is not a neighbour\n");
1716 goto release;
1717 }
1718 peer = inet_getpeer_v6(net->ipv6.peers, &ipv6_hdr(skb)->saddr, 1);
1719 ret = inet_peer_xrlim_allow(peer, 1*HZ);
1720 if (peer)
1721 inet_putpeer(peer);
1722 if (!ret)
1723 goto release;
1724
1725 if (dev->addr_len) {
1726 struct neighbour *neigh = dst_neigh_lookup(skb_dst(skb), target);
1727 if (!neigh) {
1728 ND_PRINTK(2, warn,
1729 "Redirect: no neigh for target address\n");
1730 goto release;
1731 }
1732
1733 read_lock_bh(&neigh->lock);
1734 if (neigh->nud_state & NUD_VALID) {
1735 memcpy(ha_buf, neigh->ha, dev->addr_len);
1736 read_unlock_bh(&neigh->lock);
1737 ha = ha_buf;
1738 optlen += ndisc_redirect_opt_addr_space(dev, neigh,
1739 ops_data_buf,
1740 &ops_data);
1741 } else
1742 read_unlock_bh(&neigh->lock);
1743
1744 neigh_release(neigh);
1745 }
1746
1747 rd_len = min_t(unsigned int,
1748 IPV6_MIN_MTU - sizeof(struct ipv6hdr) - sizeof(*msg) - optlen,
1749 skb->len + 8);
1750 rd_len &= ~0x7;
1751 optlen += rd_len;
1752
1753 buff = ndisc_alloc_skb(dev, sizeof(*msg) + optlen);
1754 if (!buff)
1755 goto release;
1756
1757 msg = skb_put(buff, sizeof(*msg));
1758 *msg = (struct rd_msg) {
1759 .icmph = {
1760 .icmp6_type = NDISC_REDIRECT,
1761 },
1762 .target = *target,
1763 .dest = ipv6_hdr(skb)->daddr,
1764 };
1765
1766 /*
1767 * include target_address option
1768 */
1769
1770 if (ha)
1771 ndisc_fill_redirect_addr_option(buff, ha, ops_data);
1772
1773 /*
1774 * build redirect option and copy skb over to the new packet.
1775 */
1776
1777 if (rd_len)
1778 ndisc_fill_redirect_hdr_option(buff, skb, rd_len);
1779
1780 skb_dst_set(buff, dst);
1781 ndisc_send_skb(buff, &ipv6_hdr(skb)->saddr, &saddr_buf);
1782 return;
1783
1784 release:
1785 dst_release(dst);
1786 }
1787
pndisc_redo(struct sk_buff * skb)1788 static void pndisc_redo(struct sk_buff *skb)
1789 {
1790 enum skb_drop_reason reason = ndisc_recv_ns(skb);
1791
1792 kfree_skb_reason(skb, reason);
1793 }
1794
ndisc_is_multicast(const void * pkey)1795 static int ndisc_is_multicast(const void *pkey)
1796 {
1797 return ipv6_addr_is_multicast((struct in6_addr *)pkey);
1798 }
1799
ndisc_suppress_frag_ndisc(struct sk_buff * skb)1800 static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb)
1801 {
1802 struct inet6_dev *idev = __in6_dev_get(skb->dev);
1803
1804 if (!idev)
1805 return true;
1806 if (IP6CB(skb)->flags & IP6SKB_FRAGMENTED &&
1807 idev->cnf.suppress_frag_ndisc) {
1808 net_warn_ratelimited("Received fragmented ndisc packet. Carefully consider disabling suppress_frag_ndisc.\n");
1809 return true;
1810 }
1811 return false;
1812 }
1813
ndisc_rcv(struct sk_buff * skb)1814 enum skb_drop_reason ndisc_rcv(struct sk_buff *skb)
1815 {
1816 struct nd_msg *msg;
1817 SKB_DR(reason);
1818
1819 if (ndisc_suppress_frag_ndisc(skb))
1820 return SKB_DROP_REASON_IPV6_NDISC_FRAG;
1821
1822 if (skb_linearize(skb))
1823 return SKB_DROP_REASON_NOMEM;
1824
1825 msg = (struct nd_msg *)skb_transport_header(skb);
1826
1827 __skb_push(skb, skb->data - skb_transport_header(skb));
1828
1829 if (ipv6_hdr(skb)->hop_limit != 255) {
1830 ND_PRINTK(2, warn, "NDISC: invalid hop-limit: %d\n",
1831 ipv6_hdr(skb)->hop_limit);
1832 return SKB_DROP_REASON_IPV6_NDISC_HOP_LIMIT;
1833 }
1834
1835 if (msg->icmph.icmp6_code != 0) {
1836 ND_PRINTK(2, warn, "NDISC: invalid ICMPv6 code: %d\n",
1837 msg->icmph.icmp6_code);
1838 return SKB_DROP_REASON_IPV6_NDISC_BAD_CODE;
1839 }
1840
1841 switch (msg->icmph.icmp6_type) {
1842 case NDISC_NEIGHBOUR_SOLICITATION:
1843 memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb));
1844 reason = ndisc_recv_ns(skb);
1845 break;
1846
1847 case NDISC_NEIGHBOUR_ADVERTISEMENT:
1848 reason = ndisc_recv_na(skb);
1849 break;
1850
1851 case NDISC_ROUTER_SOLICITATION:
1852 reason = ndisc_recv_rs(skb);
1853 break;
1854
1855 case NDISC_ROUTER_ADVERTISEMENT:
1856 reason = ndisc_router_discovery(skb);
1857 break;
1858
1859 case NDISC_REDIRECT:
1860 reason = ndisc_redirect_rcv(skb);
1861 break;
1862 }
1863
1864 return reason;
1865 }
1866
ndisc_netdev_event(struct notifier_block * this,unsigned long event,void * ptr)1867 static int ndisc_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
1868 {
1869 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1870 struct netdev_notifier_change_info *change_info;
1871 struct net *net = dev_net(dev);
1872 struct inet6_dev *idev;
1873 bool evict_nocarrier;
1874
1875 switch (event) {
1876 case NETDEV_CHANGEADDR:
1877 neigh_changeaddr(&nd_tbl, dev);
1878 fib6_run_gc(0, net, false);
1879 fallthrough;
1880 case NETDEV_UP:
1881 idev = in6_dev_get(dev);
1882 if (!idev)
1883 break;
1884 if (idev->cnf.ndisc_notify ||
1885 net->ipv6.devconf_all->ndisc_notify)
1886 ndisc_send_unsol_na(dev);
1887 in6_dev_put(idev);
1888 break;
1889 case NETDEV_CHANGE:
1890 idev = in6_dev_get(dev);
1891 if (!idev)
1892 evict_nocarrier = true;
1893 else {
1894 evict_nocarrier = idev->cnf.ndisc_evict_nocarrier &&
1895 net->ipv6.devconf_all->ndisc_evict_nocarrier;
1896 in6_dev_put(idev);
1897 }
1898
1899 change_info = ptr;
1900 if (change_info->flags_changed & IFF_NOARP)
1901 neigh_changeaddr(&nd_tbl, dev);
1902 if (evict_nocarrier && !netif_carrier_ok(dev))
1903 neigh_carrier_down(&nd_tbl, dev);
1904 break;
1905 case NETDEV_DOWN:
1906 neigh_ifdown(&nd_tbl, dev);
1907 fib6_run_gc(0, net, false);
1908 break;
1909 case NETDEV_NOTIFY_PEERS:
1910 ndisc_send_unsol_na(dev);
1911 break;
1912 default:
1913 break;
1914 }
1915
1916 return NOTIFY_DONE;
1917 }
1918
1919 static struct notifier_block ndisc_netdev_notifier = {
1920 .notifier_call = ndisc_netdev_event,
1921 .priority = ADDRCONF_NOTIFY_PRIORITY - 5,
1922 };
1923
1924 #ifdef CONFIG_SYSCTL
ndisc_warn_deprecated_sysctl(struct ctl_table * ctl,const char * func,const char * dev_name)1925 static void ndisc_warn_deprecated_sysctl(struct ctl_table *ctl,
1926 const char *func, const char *dev_name)
1927 {
1928 static char warncomm[TASK_COMM_LEN];
1929 static int warned;
1930 if (strcmp(warncomm, current->comm) && warned < 5) {
1931 strcpy(warncomm, current->comm);
1932 pr_warn("process `%s' is using deprecated sysctl (%s) net.ipv6.neigh.%s.%s - use net.ipv6.neigh.%s.%s_ms instead\n",
1933 warncomm, func,
1934 dev_name, ctl->procname,
1935 dev_name, ctl->procname);
1936 warned++;
1937 }
1938 }
1939
ndisc_ifinfo_sysctl_change(struct ctl_table * ctl,int write,void * buffer,size_t * lenp,loff_t * ppos)1940 int ndisc_ifinfo_sysctl_change(struct ctl_table *ctl, int write, void *buffer,
1941 size_t *lenp, loff_t *ppos)
1942 {
1943 struct net_device *dev = ctl->extra1;
1944 struct inet6_dev *idev;
1945 int ret;
1946
1947 if ((strcmp(ctl->procname, "retrans_time") == 0) ||
1948 (strcmp(ctl->procname, "base_reachable_time") == 0))
1949 ndisc_warn_deprecated_sysctl(ctl, "syscall", dev ? dev->name : "default");
1950
1951 if (strcmp(ctl->procname, "retrans_time") == 0)
1952 ret = neigh_proc_dointvec(ctl, write, buffer, lenp, ppos);
1953
1954 else if (strcmp(ctl->procname, "base_reachable_time") == 0)
1955 ret = neigh_proc_dointvec_jiffies(ctl, write,
1956 buffer, lenp, ppos);
1957
1958 else if ((strcmp(ctl->procname, "retrans_time_ms") == 0) ||
1959 (strcmp(ctl->procname, "base_reachable_time_ms") == 0))
1960 ret = neigh_proc_dointvec_ms_jiffies(ctl, write,
1961 buffer, lenp, ppos);
1962 else
1963 ret = -1;
1964
1965 if (write && ret == 0 && dev && (idev = in6_dev_get(dev)) != NULL) {
1966 if (ctl->data == &NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME))
1967 idev->nd_parms->reachable_time =
1968 neigh_rand_reach_time(NEIGH_VAR(idev->nd_parms, BASE_REACHABLE_TIME));
1969 idev->tstamp = jiffies;
1970 inet6_ifinfo_notify(RTM_NEWLINK, idev);
1971 in6_dev_put(idev);
1972 }
1973 return ret;
1974 }
1975
1976
1977 #endif
1978
ndisc_net_init(struct net * net)1979 static int __net_init ndisc_net_init(struct net *net)
1980 {
1981 struct ipv6_pinfo *np;
1982 struct sock *sk;
1983 int err;
1984
1985 err = inet_ctl_sock_create(&sk, PF_INET6,
1986 SOCK_RAW, IPPROTO_ICMPV6, net);
1987 if (err < 0) {
1988 ND_PRINTK(0, err,
1989 "NDISC: Failed to initialize the control socket (err %d)\n",
1990 err);
1991 return err;
1992 }
1993
1994 net->ipv6.ndisc_sk = sk;
1995
1996 np = inet6_sk(sk);
1997 np->hop_limit = 255;
1998 /* Do not loopback ndisc messages */
1999 np->mc_loop = 0;
2000
2001 return 0;
2002 }
2003
ndisc_net_exit(struct net * net)2004 static void __net_exit ndisc_net_exit(struct net *net)
2005 {
2006 inet_ctl_sock_destroy(net->ipv6.ndisc_sk);
2007 }
2008
2009 static struct pernet_operations ndisc_net_ops = {
2010 .init = ndisc_net_init,
2011 .exit = ndisc_net_exit,
2012 };
2013
ndisc_init(void)2014 int __init ndisc_init(void)
2015 {
2016 int err;
2017
2018 err = register_pernet_subsys(&ndisc_net_ops);
2019 if (err)
2020 return err;
2021 /*
2022 * Initialize the neighbour table
2023 */
2024 neigh_table_init(NEIGH_ND_TABLE, &nd_tbl);
2025
2026 #ifdef CONFIG_SYSCTL
2027 err = neigh_sysctl_register(NULL, &nd_tbl.parms,
2028 ndisc_ifinfo_sysctl_change);
2029 if (err)
2030 goto out_unregister_pernet;
2031 out:
2032 #endif
2033 return err;
2034
2035 #ifdef CONFIG_SYSCTL
2036 out_unregister_pernet:
2037 unregister_pernet_subsys(&ndisc_net_ops);
2038 goto out;
2039 #endif
2040 }
2041
ndisc_late_init(void)2042 int __init ndisc_late_init(void)
2043 {
2044 return register_netdevice_notifier(&ndisc_netdev_notifier);
2045 }
2046
ndisc_late_cleanup(void)2047 void ndisc_late_cleanup(void)
2048 {
2049 unregister_netdevice_notifier(&ndisc_netdev_notifier);
2050 }
2051
ndisc_cleanup(void)2052 void ndisc_cleanup(void)
2053 {
2054 #ifdef CONFIG_SYSCTL
2055 neigh_sysctl_unregister(&nd_tbl.parms);
2056 #endif
2057 neigh_table_clear(NEIGH_ND_TABLE, &nd_tbl);
2058 unregister_pernet_subsys(&ndisc_net_ops);
2059 }
2060