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1/*
2 * Extension Header handling for IPv6
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 * Andi Kleen <ak@muc.de>
8 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16/* Changes:
17 * yoshfuji : ensure not to overrun while parsing
18 * tlv options.
19 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
20 * YOSHIFUJI Hideaki @USAGI Register inbound extension header
21 * handlers as inet6_protocol{}.
22 */
23
24#include <linux/errno.h>
25#include <linux/types.h>
26#include <linux/socket.h>
27#include <linux/sockios.h>
28#include <linux/net.h>
29#include <linux/netdevice.h>
30#include <linux/in6.h>
31#include <linux/icmpv6.h>
32#include <linux/slab.h>
33#include <linux/export.h>
34
35#include <net/dst.h>
36#include <net/sock.h>
37#include <net/snmp.h>
38
39#include <net/ipv6.h>
40#include <net/protocol.h>
41#include <net/transp_v6.h>
42#include <net/rawv6.h>
43#include <net/ndisc.h>
44#include <net/ip6_route.h>
45#include <net/addrconf.h>
46#if IS_ENABLED(CONFIG_IPV6_MIP6)
47#include <net/xfrm.h>
48#endif
49
50#include <linux/uaccess.h>
51
52/*
53 * Parsing tlv encoded headers.
54 *
55 * Parsing function "func" returns true, if parsing succeed
56 * and false, if it failed.
57 * It MUST NOT touch skb->h.
58 */
59
60struct tlvtype_proc {
61 int type;
62 bool (*func)(struct sk_buff *skb, int offset);
63};
64
65/*********************
66 Generic functions
67 *********************/
68
69/* An unknown option is detected, decide what to do */
70
71static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
72{
73 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
74 case 0: /* ignore */
75 return true;
76
77 case 1: /* drop packet */
78 break;
79
80 case 3: /* Send ICMP if not a multicast address and drop packet */
81 /* Actually, it is redundant check. icmp_send
82 will recheck in any case.
83 */
84 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
85 break;
86 case 2: /* send ICMP PARM PROB regardless and drop packet */
87 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
88 return false;
89 }
90
91 kfree_skb(skb);
92 return false;
93}
94
95/* Parse tlv encoded option header (hop-by-hop or destination) */
96
97static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
98{
99 const struct tlvtype_proc *curr;
100 const unsigned char *nh = skb_network_header(skb);
101 int off = skb_network_header_len(skb);
102 int len = (skb_transport_header(skb)[1] + 1) << 3;
103 int padlen = 0;
104
105 if (skb_transport_offset(skb) + len > skb_headlen(skb))
106 goto bad;
107
108 off += 2;
109 len -= 2;
110
111 while (len > 0) {
112 int optlen = nh[off + 1] + 2;
113 int i;
114
115 switch (nh[off]) {
116 case IPV6_TLV_PAD1:
117 optlen = 1;
118 padlen++;
119 if (padlen > 7)
120 goto bad;
121 break;
122
123 case IPV6_TLV_PADN:
124 /* RFC 2460 states that the purpose of PadN is
125 * to align the containing header to multiples
126 * of 8. 7 is therefore the highest valid value.
127 * See also RFC 4942, Section 2.1.9.5.
128 */
129 padlen += optlen;
130 if (padlen > 7)
131 goto bad;
132 /* RFC 4942 recommends receiving hosts to
133 * actively check PadN payload to contain
134 * only zeroes.
135 */
136 for (i = 2; i < optlen; i++) {
137 if (nh[off + i] != 0)
138 goto bad;
139 }
140 break;
141
142 default: /* Other TLV code so scan list */
143 if (optlen > len)
144 goto bad;
145 for (curr = procs; curr->type >= 0; curr++) {
146 if (curr->type == nh[off]) {
147 /* type specific length/alignment
148 checks will be performed in the
149 func(). */
150 if (curr->func(skb, off) == false)
151 return false;
152 break;
153 }
154 }
155 if (curr->type < 0) {
156 if (ip6_tlvopt_unknown(skb, off) == 0)
157 return false;
158 }
159 padlen = 0;
160 break;
161 }
162 off += optlen;
163 len -= optlen;
164 }
165
166 if (len == 0)
167 return true;
168bad:
169 kfree_skb(skb);
170 return false;
171}
172
173/*****************************
174 Destination options header.
175 *****************************/
176
177#if IS_ENABLED(CONFIG_IPV6_MIP6)
178static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
179{
180 struct ipv6_destopt_hao *hao;
181 struct inet6_skb_parm *opt = IP6CB(skb);
182 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
183 struct in6_addr tmp_addr;
184 int ret;
185
186 if (opt->dsthao) {
187 net_dbg_ratelimited("hao duplicated\n");
188 goto discard;
189 }
190 opt->dsthao = opt->dst1;
191 opt->dst1 = 0;
192
193 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
194
195 if (hao->length != 16) {
196 net_dbg_ratelimited("hao invalid option length = %d\n",
197 hao->length);
198 goto discard;
199 }
200
201 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
202 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
203 &hao->addr);
204 goto discard;
205 }
206
207 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
208 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
209 if (unlikely(ret < 0))
210 goto discard;
211
212 if (skb_cloned(skb)) {
213 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
214 goto discard;
215
216 /* update all variable using below by copied skbuff */
217 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
218 optoff);
219 ipv6h = ipv6_hdr(skb);
220 }
221
222 if (skb->ip_summed == CHECKSUM_COMPLETE)
223 skb->ip_summed = CHECKSUM_NONE;
224
225 tmp_addr = ipv6h->saddr;
226 ipv6h->saddr = hao->addr;
227 hao->addr = tmp_addr;
228
229 if (skb->tstamp.tv64 == 0)
230 __net_timestamp(skb);
231
232 return true;
233
234 discard:
235 kfree_skb(skb);
236 return false;
237}
238#endif
239
240static const struct tlvtype_proc tlvprocdestopt_lst[] = {
241#if IS_ENABLED(CONFIG_IPV6_MIP6)
242 {
243 .type = IPV6_TLV_HAO,
244 .func = ipv6_dest_hao,
245 },
246#endif
247 {-1, NULL}
248};
249
250static int ipv6_destopt_rcv(struct sk_buff *skb)
251{
252 struct inet6_skb_parm *opt = IP6CB(skb);
253#if IS_ENABLED(CONFIG_IPV6_MIP6)
254 __u16 dstbuf;
255#endif
256 struct dst_entry *dst = skb_dst(skb);
257
258 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
259 !pskb_may_pull(skb, (skb_transport_offset(skb) +
260 ((skb_transport_header(skb)[1] + 1) << 3)))) {
261 IP6_INC_STATS_BH(dev_net(dst->dev), ip6_dst_idev(dst),
262 IPSTATS_MIB_INHDRERRORS);
263 kfree_skb(skb);
264 return -1;
265 }
266
267 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
268#if IS_ENABLED(CONFIG_IPV6_MIP6)
269 dstbuf = opt->dst1;
270#endif
271
272 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
273 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
274 opt = IP6CB(skb);
275#if IS_ENABLED(CONFIG_IPV6_MIP6)
276 opt->nhoff = dstbuf;
277#else
278 opt->nhoff = opt->dst1;
279#endif
280 return 1;
281 }
282
283 IP6_INC_STATS_BH(dev_net(dst->dev),
284 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
285 return -1;
286}
287
288/********************************
289 Routing header.
290 ********************************/
291
292/* called with rcu_read_lock() */
293static int ipv6_rthdr_rcv(struct sk_buff *skb)
294{
295 struct inet6_skb_parm *opt = IP6CB(skb);
296 struct in6_addr *addr = NULL;
297 struct in6_addr daddr;
298 struct inet6_dev *idev;
299 int n, i;
300 struct ipv6_rt_hdr *hdr;
301 struct rt0_hdr *rthdr;
302 struct net *net = dev_net(skb->dev);
303 int accept_source_route = net->ipv6.devconf_all->accept_source_route;
304
305 idev = __in6_dev_get(skb->dev);
306 if (idev && accept_source_route > idev->cnf.accept_source_route)
307 accept_source_route = idev->cnf.accept_source_route;
308
309 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
310 !pskb_may_pull(skb, (skb_transport_offset(skb) +
311 ((skb_transport_header(skb)[1] + 1) << 3)))) {
312 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
313 IPSTATS_MIB_INHDRERRORS);
314 kfree_skb(skb);
315 return -1;
316 }
317
318 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
319
320 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
321 skb->pkt_type != PACKET_HOST) {
322 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
323 IPSTATS_MIB_INADDRERRORS);
324 kfree_skb(skb);
325 return -1;
326 }
327
328looped_back:
329 if (hdr->segments_left == 0) {
330 switch (hdr->type) {
331#if IS_ENABLED(CONFIG_IPV6_MIP6)
332 case IPV6_SRCRT_TYPE_2:
333 /* Silently discard type 2 header unless it was
334 * processed by own
335 */
336 if (!addr) {
337 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
338 IPSTATS_MIB_INADDRERRORS);
339 kfree_skb(skb);
340 return -1;
341 }
342 break;
343#endif
344 default:
345 break;
346 }
347
348 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
349 skb->transport_header += (hdr->hdrlen + 1) << 3;
350 opt->dst0 = opt->dst1;
351 opt->dst1 = 0;
352 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
353 return 1;
354 }
355
356 switch (hdr->type) {
357#if IS_ENABLED(CONFIG_IPV6_MIP6)
358 case IPV6_SRCRT_TYPE_2:
359 if (accept_source_route < 0)
360 goto unknown_rh;
361 /* Silently discard invalid RTH type 2 */
362 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
363 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
364 IPSTATS_MIB_INHDRERRORS);
365 kfree_skb(skb);
366 return -1;
367 }
368 break;
369#endif
370 default:
371 goto unknown_rh;
372 }
373
374 /*
375 * This is the routing header forwarding algorithm from
376 * RFC 2460, page 16.
377 */
378
379 n = hdr->hdrlen >> 1;
380
381 if (hdr->segments_left > n) {
382 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
383 IPSTATS_MIB_INHDRERRORS);
384 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
385 ((&hdr->segments_left) -
386 skb_network_header(skb)));
387 return -1;
388 }
389
390 /* We are about to mangle packet header. Be careful!
391 Do not damage packets queued somewhere.
392 */
393 if (skb_cloned(skb)) {
394 /* the copy is a forwarded packet */
395 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
396 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
397 IPSTATS_MIB_OUTDISCARDS);
398 kfree_skb(skb);
399 return -1;
400 }
401 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
402 }
403
404 if (skb->ip_summed == CHECKSUM_COMPLETE)
405 skb->ip_summed = CHECKSUM_NONE;
406
407 i = n - --hdr->segments_left;
408
409 rthdr = (struct rt0_hdr *) hdr;
410 addr = rthdr->addr;
411 addr += i - 1;
412
413 switch (hdr->type) {
414#if IS_ENABLED(CONFIG_IPV6_MIP6)
415 case IPV6_SRCRT_TYPE_2:
416 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
417 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
418 IPPROTO_ROUTING) < 0) {
419 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
420 IPSTATS_MIB_INADDRERRORS);
421 kfree_skb(skb);
422 return -1;
423 }
424 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
425 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
426 IPSTATS_MIB_INADDRERRORS);
427 kfree_skb(skb);
428 return -1;
429 }
430 break;
431#endif
432 default:
433 break;
434 }
435
436 if (ipv6_addr_is_multicast(addr)) {
437 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
438 IPSTATS_MIB_INADDRERRORS);
439 kfree_skb(skb);
440 return -1;
441 }
442
443 daddr = *addr;
444 *addr = ipv6_hdr(skb)->daddr;
445 ipv6_hdr(skb)->daddr = daddr;
446
447 skb_dst_drop(skb);
448 ip6_route_input(skb);
449 if (skb_dst(skb)->error) {
450 skb_push(skb, skb->data - skb_network_header(skb));
451 dst_input(skb);
452 return -1;
453 }
454
455 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
456 if (ipv6_hdr(skb)->hop_limit <= 1) {
457 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
458 IPSTATS_MIB_INHDRERRORS);
459 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
460 0);
461 kfree_skb(skb);
462 return -1;
463 }
464 ipv6_hdr(skb)->hop_limit--;
465 goto looped_back;
466 }
467
468 skb_push(skb, skb->data - skb_network_header(skb));
469 dst_input(skb);
470 return -1;
471
472unknown_rh:
473 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
474 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
475 (&hdr->type) - skb_network_header(skb));
476 return -1;
477}
478
479static const struct inet6_protocol rthdr_protocol = {
480 .handler = ipv6_rthdr_rcv,
481 .flags = INET6_PROTO_NOPOLICY,
482};
483
484static const struct inet6_protocol destopt_protocol = {
485 .handler = ipv6_destopt_rcv,
486 .flags = INET6_PROTO_NOPOLICY,
487};
488
489static const struct inet6_protocol nodata_protocol = {
490 .handler = dst_discard,
491 .flags = INET6_PROTO_NOPOLICY,
492};
493
494int __init ipv6_exthdrs_init(void)
495{
496 int ret;
497
498 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
499 if (ret)
500 goto out;
501
502 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
503 if (ret)
504 goto out_rthdr;
505
506 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
507 if (ret)
508 goto out_destopt;
509
510out:
511 return ret;
512out_destopt:
513 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
514out_rthdr:
515 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
516 goto out;
517};
518
519void ipv6_exthdrs_exit(void)
520{
521 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
522 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
523 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
524}
525
526/**********************************
527 Hop-by-hop options.
528 **********************************/
529
530/*
531 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
532 */
533static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
534{
535 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
536}
537
538static inline struct net *ipv6_skb_net(struct sk_buff *skb)
539{
540 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
541}
542
543/* Router Alert as of RFC 2711 */
544
545static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
546{
547 const unsigned char *nh = skb_network_header(skb);
548
549 if (nh[optoff + 1] == 2) {
550 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
551 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
552 return true;
553 }
554 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
555 nh[optoff + 1]);
556 kfree_skb(skb);
557 return false;
558}
559
560/* Jumbo payload */
561
562static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
563{
564 const unsigned char *nh = skb_network_header(skb);
565 struct net *net = ipv6_skb_net(skb);
566 u32 pkt_len;
567
568 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
569 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
570 nh[optoff+1]);
571 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
572 IPSTATS_MIB_INHDRERRORS);
573 goto drop;
574 }
575
576 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
577 if (pkt_len <= IPV6_MAXPLEN) {
578 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
579 IPSTATS_MIB_INHDRERRORS);
580 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
581 return false;
582 }
583 if (ipv6_hdr(skb)->payload_len) {
584 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
585 IPSTATS_MIB_INHDRERRORS);
586 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
587 return false;
588 }
589
590 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
591 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
592 IPSTATS_MIB_INTRUNCATEDPKTS);
593 goto drop;
594 }
595
596 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
597 goto drop;
598
599 return true;
600
601drop:
602 kfree_skb(skb);
603 return false;
604}
605
606static const struct tlvtype_proc tlvprochopopt_lst[] = {
607 {
608 .type = IPV6_TLV_ROUTERALERT,
609 .func = ipv6_hop_ra,
610 },
611 {
612 .type = IPV6_TLV_JUMBO,
613 .func = ipv6_hop_jumbo,
614 },
615 { -1, }
616};
617
618int ipv6_parse_hopopts(struct sk_buff *skb)
619{
620 struct inet6_skb_parm *opt = IP6CB(skb);
621
622 /*
623 * skb_network_header(skb) is equal to skb->data, and
624 * skb_network_header_len(skb) is always equal to
625 * sizeof(struct ipv6hdr) by definition of
626 * hop-by-hop options.
627 */
628 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
629 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
630 ((skb_transport_header(skb)[1] + 1) << 3)))) {
631 kfree_skb(skb);
632 return -1;
633 }
634
635 opt->flags |= IP6SKB_HOPBYHOP;
636 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
637 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
638 opt = IP6CB(skb);
639 opt->nhoff = sizeof(struct ipv6hdr);
640 return 1;
641 }
642 return -1;
643}
644
645/*
646 * Creating outbound headers.
647 *
648 * "build" functions work when skb is filled from head to tail (datagram)
649 * "push" functions work when headers are added from tail to head (tcp)
650 *
651 * In both cases we assume, that caller reserved enough room
652 * for headers.
653 */
654
655static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
656 struct ipv6_rt_hdr *opt,
657 struct in6_addr **addr_p)
658{
659 struct rt0_hdr *phdr, *ihdr;
660 int hops;
661
662 ihdr = (struct rt0_hdr *) opt;
663
664 phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
665 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
666
667 hops = ihdr->rt_hdr.hdrlen >> 1;
668
669 if (hops > 1)
670 memcpy(phdr->addr, ihdr->addr + 1,
671 (hops - 1) * sizeof(struct in6_addr));
672
673 phdr->addr[hops - 1] = **addr_p;
674 *addr_p = ihdr->addr;
675
676 phdr->rt_hdr.nexthdr = *proto;
677 *proto = NEXTHDR_ROUTING;
678}
679
680static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
681{
682 struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
683
684 memcpy(h, opt, ipv6_optlen(opt));
685 h->nexthdr = *proto;
686 *proto = type;
687}
688
689void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
690 u8 *proto,
691 struct in6_addr **daddr)
692{
693 if (opt->srcrt) {
694 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
695 /*
696 * IPV6_RTHDRDSTOPTS is ignored
697 * unless IPV6_RTHDR is set (RFC3542).
698 */
699 if (opt->dst0opt)
700 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
701 }
702 if (opt->hopopt)
703 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
704}
705EXPORT_SYMBOL(ipv6_push_nfrag_opts);
706
707void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
708{
709 if (opt->dst1opt)
710 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
711}
712
713struct ipv6_txoptions *
714ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
715{
716 struct ipv6_txoptions *opt2;
717
718 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
719 if (opt2) {
720 long dif = (char *)opt2 - (char *)opt;
721 memcpy(opt2, opt, opt->tot_len);
722 if (opt2->hopopt)
723 *((char **)&opt2->hopopt) += dif;
724 if (opt2->dst0opt)
725 *((char **)&opt2->dst0opt) += dif;
726 if (opt2->dst1opt)
727 *((char **)&opt2->dst1opt) += dif;
728 if (opt2->srcrt)
729 *((char **)&opt2->srcrt) += dif;
730 atomic_set(&opt2->refcnt, 1);
731 }
732 return opt2;
733}
734EXPORT_SYMBOL_GPL(ipv6_dup_options);
735
736static int ipv6_renew_option(void *ohdr,
737 struct ipv6_opt_hdr __user *newopt, int newoptlen,
738 int inherit,
739 struct ipv6_opt_hdr **hdr,
740 char **p)
741{
742 if (inherit) {
743 if (ohdr) {
744 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
745 *hdr = (struct ipv6_opt_hdr *)*p;
746 *p += CMSG_ALIGN(ipv6_optlen(*hdr));
747 }
748 } else {
749 if (newopt) {
750 if (copy_from_user(*p, newopt, newoptlen))
751 return -EFAULT;
752 *hdr = (struct ipv6_opt_hdr *)*p;
753 if (ipv6_optlen(*hdr) > newoptlen)
754 return -EINVAL;
755 *p += CMSG_ALIGN(newoptlen);
756 }
757 }
758 return 0;
759}
760
761struct ipv6_txoptions *
762ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
763 int newtype,
764 struct ipv6_opt_hdr __user *newopt, int newoptlen)
765{
766 int tot_len = 0;
767 char *p;
768 struct ipv6_txoptions *opt2;
769 int err;
770
771 if (opt) {
772 if (newtype != IPV6_HOPOPTS && opt->hopopt)
773 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
774 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
775 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
776 if (newtype != IPV6_RTHDR && opt->srcrt)
777 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
778 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
779 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
780 }
781
782 if (newopt && newoptlen)
783 tot_len += CMSG_ALIGN(newoptlen);
784
785 if (!tot_len)
786 return NULL;
787
788 tot_len += sizeof(*opt2);
789 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
790 if (!opt2)
791 return ERR_PTR(-ENOBUFS);
792
793 memset(opt2, 0, tot_len);
794 atomic_set(&opt2->refcnt, 1);
795 opt2->tot_len = tot_len;
796 p = (char *)(opt2 + 1);
797
798 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
799 newtype != IPV6_HOPOPTS,
800 &opt2->hopopt, &p);
801 if (err)
802 goto out;
803
804 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
805 newtype != IPV6_RTHDRDSTOPTS,
806 &opt2->dst0opt, &p);
807 if (err)
808 goto out;
809
810 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
811 newtype != IPV6_RTHDR,
812 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
813 if (err)
814 goto out;
815
816 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
817 newtype != IPV6_DSTOPTS,
818 &opt2->dst1opt, &p);
819 if (err)
820 goto out;
821
822 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
823 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
824 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
825 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
826
827 return opt2;
828out:
829 sock_kfree_s(sk, opt2, opt2->tot_len);
830 return ERR_PTR(err);
831}
832
833struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
834 struct ipv6_txoptions *opt)
835{
836 /*
837 * ignore the dest before srcrt unless srcrt is being included.
838 * --yoshfuji
839 */
840 if (opt && opt->dst0opt && !opt->srcrt) {
841 if (opt_space != opt) {
842 memcpy(opt_space, opt, sizeof(*opt_space));
843 opt = opt_space;
844 }
845 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
846 opt->dst0opt = NULL;
847 }
848
849 return opt;
850}
851EXPORT_SYMBOL_GPL(ipv6_fixup_options);
852
853/**
854 * fl6_update_dst - update flowi destination address with info given
855 * by srcrt option, if any.
856 *
857 * @fl6: flowi6 for which daddr is to be updated
858 * @opt: struct ipv6_txoptions in which to look for srcrt opt
859 * @orig: copy of original daddr address if modified
860 *
861 * Returns NULL if no txoptions or no srcrt, otherwise returns orig
862 * and initial value of fl6->daddr set in orig
863 */
864struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
865 const struct ipv6_txoptions *opt,
866 struct in6_addr *orig)
867{
868 if (!opt || !opt->srcrt)
869 return NULL;
870
871 *orig = fl6->daddr;
872 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
873 return orig;
874}
875EXPORT_SYMBOL_GPL(fl6_update_dst);
1/*
2 * Extension Header handling for IPv6
3 * Linux INET6 implementation
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 * Andi Kleen <ak@muc.de>
8 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16/* Changes:
17 * yoshfuji : ensure not to overrun while parsing
18 * tlv options.
19 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
20 * YOSHIFUJI Hideaki @USAGI Register inbound extension header
21 * handlers as inet6_protocol{}.
22 */
23
24#include <linux/errno.h>
25#include <linux/types.h>
26#include <linux/socket.h>
27#include <linux/sockios.h>
28#include <linux/net.h>
29#include <linux/netdevice.h>
30#include <linux/in6.h>
31#include <linux/icmpv6.h>
32#include <linux/slab.h>
33#include <linux/export.h>
34
35#include <net/dst.h>
36#include <net/sock.h>
37#include <net/snmp.h>
38
39#include <net/ipv6.h>
40#include <net/protocol.h>
41#include <net/transp_v6.h>
42#include <net/rawv6.h>
43#include <net/ndisc.h>
44#include <net/ip6_route.h>
45#include <net/addrconf.h>
46#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
47#include <net/xfrm.h>
48#endif
49
50#include <asm/uaccess.h>
51
52int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
53{
54 const unsigned char *nh = skb_network_header(skb);
55 int packet_len = skb->tail - skb->network_header;
56 struct ipv6_opt_hdr *hdr;
57 int len;
58
59 if (offset + 2 > packet_len)
60 goto bad;
61 hdr = (struct ipv6_opt_hdr *)(nh + offset);
62 len = ((hdr->hdrlen + 1) << 3);
63
64 if (offset + len > packet_len)
65 goto bad;
66
67 offset += 2;
68 len -= 2;
69
70 while (len > 0) {
71 int opttype = nh[offset];
72 int optlen;
73
74 if (opttype == type)
75 return offset;
76
77 switch (opttype) {
78 case IPV6_TLV_PAD1:
79 optlen = 1;
80 break;
81 default:
82 optlen = nh[offset + 1] + 2;
83 if (optlen > len)
84 goto bad;
85 break;
86 }
87 offset += optlen;
88 len -= optlen;
89 }
90 /* not_found */
91 bad:
92 return -1;
93}
94EXPORT_SYMBOL_GPL(ipv6_find_tlv);
95
96/*
97 * Parsing tlv encoded headers.
98 *
99 * Parsing function "func" returns true, if parsing succeed
100 * and false, if it failed.
101 * It MUST NOT touch skb->h.
102 */
103
104struct tlvtype_proc {
105 int type;
106 bool (*func)(struct sk_buff *skb, int offset);
107};
108
109/*********************
110 Generic functions
111 *********************/
112
113/* An unknown option is detected, decide what to do */
114
115static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
116{
117 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
118 case 0: /* ignore */
119 return true;
120
121 case 1: /* drop packet */
122 break;
123
124 case 3: /* Send ICMP if not a multicast address and drop packet */
125 /* Actually, it is redundant check. icmp_send
126 will recheck in any case.
127 */
128 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
129 break;
130 case 2: /* send ICMP PARM PROB regardless and drop packet */
131 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
132 return false;
133 }
134
135 kfree_skb(skb);
136 return false;
137}
138
139/* Parse tlv encoded option header (hop-by-hop or destination) */
140
141static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb)
142{
143 const struct tlvtype_proc *curr;
144 const unsigned char *nh = skb_network_header(skb);
145 int off = skb_network_header_len(skb);
146 int len = (skb_transport_header(skb)[1] + 1) << 3;
147 int padlen = 0;
148
149 if (skb_transport_offset(skb) + len > skb_headlen(skb))
150 goto bad;
151
152 off += 2;
153 len -= 2;
154
155 while (len > 0) {
156 int optlen = nh[off + 1] + 2;
157 int i;
158
159 switch (nh[off]) {
160 case IPV6_TLV_PAD1:
161 optlen = 1;
162 padlen++;
163 if (padlen > 7)
164 goto bad;
165 break;
166
167 case IPV6_TLV_PADN:
168 /* RFC 2460 states that the purpose of PadN is
169 * to align the containing header to multiples
170 * of 8. 7 is therefore the highest valid value.
171 * See also RFC 4942, Section 2.1.9.5.
172 */
173 padlen += optlen;
174 if (padlen > 7)
175 goto bad;
176 /* RFC 4942 recommends receiving hosts to
177 * actively check PadN payload to contain
178 * only zeroes.
179 */
180 for (i = 2; i < optlen; i++) {
181 if (nh[off + i] != 0)
182 goto bad;
183 }
184 break;
185
186 default: /* Other TLV code so scan list */
187 if (optlen > len)
188 goto bad;
189 for (curr=procs; curr->type >= 0; curr++) {
190 if (curr->type == nh[off]) {
191 /* type specific length/alignment
192 checks will be performed in the
193 func(). */
194 if (curr->func(skb, off) == false)
195 return false;
196 break;
197 }
198 }
199 if (curr->type < 0) {
200 if (ip6_tlvopt_unknown(skb, off) == 0)
201 return false;
202 }
203 padlen = 0;
204 break;
205 }
206 off += optlen;
207 len -= optlen;
208 }
209 /* This case will not be caught by above check since its padding
210 * length is smaller than 7:
211 * 1 byte NH + 1 byte Length + 6 bytes Padding
212 */
213 if ((padlen == 6) && ((off - skb_network_header_len(skb)) == 8))
214 goto bad;
215
216 if (len == 0)
217 return true;
218bad:
219 kfree_skb(skb);
220 return false;
221}
222
223/*****************************
224 Destination options header.
225 *****************************/
226
227#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
228static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
229{
230 struct ipv6_destopt_hao *hao;
231 struct inet6_skb_parm *opt = IP6CB(skb);
232 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
233 struct in6_addr tmp_addr;
234 int ret;
235
236 if (opt->dsthao) {
237 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
238 goto discard;
239 }
240 opt->dsthao = opt->dst1;
241 opt->dst1 = 0;
242
243 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
244
245 if (hao->length != 16) {
246 LIMIT_NETDEBUG(
247 KERN_DEBUG "hao invalid option length = %d\n", hao->length);
248 goto discard;
249 }
250
251 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
252 LIMIT_NETDEBUG(
253 KERN_DEBUG "hao is not an unicast addr: %pI6\n", &hao->addr);
254 goto discard;
255 }
256
257 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
258 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
259 if (unlikely(ret < 0))
260 goto discard;
261
262 if (skb_cloned(skb)) {
263 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
264 goto discard;
265
266 /* update all variable using below by copied skbuff */
267 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
268 optoff);
269 ipv6h = ipv6_hdr(skb);
270 }
271
272 if (skb->ip_summed == CHECKSUM_COMPLETE)
273 skb->ip_summed = CHECKSUM_NONE;
274
275 tmp_addr = ipv6h->saddr;
276 ipv6h->saddr = hao->addr;
277 hao->addr = tmp_addr;
278
279 if (skb->tstamp.tv64 == 0)
280 __net_timestamp(skb);
281
282 return true;
283
284 discard:
285 kfree_skb(skb);
286 return false;
287}
288#endif
289
290static const struct tlvtype_proc tlvprocdestopt_lst[] = {
291#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
292 {
293 .type = IPV6_TLV_HAO,
294 .func = ipv6_dest_hao,
295 },
296#endif
297 {-1, NULL}
298};
299
300static int ipv6_destopt_rcv(struct sk_buff *skb)
301{
302 struct inet6_skb_parm *opt = IP6CB(skb);
303#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
304 __u16 dstbuf;
305#endif
306 struct dst_entry *dst = skb_dst(skb);
307
308 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
309 !pskb_may_pull(skb, (skb_transport_offset(skb) +
310 ((skb_transport_header(skb)[1] + 1) << 3)))) {
311 IP6_INC_STATS_BH(dev_net(dst->dev), ip6_dst_idev(dst),
312 IPSTATS_MIB_INHDRERRORS);
313 kfree_skb(skb);
314 return -1;
315 }
316
317 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
318#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
319 dstbuf = opt->dst1;
320#endif
321
322 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
323 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
324 opt = IP6CB(skb);
325#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
326 opt->nhoff = dstbuf;
327#else
328 opt->nhoff = opt->dst1;
329#endif
330 return 1;
331 }
332
333 IP6_INC_STATS_BH(dev_net(dst->dev),
334 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
335 return -1;
336}
337
338/********************************
339 Routing header.
340 ********************************/
341
342/* called with rcu_read_lock() */
343static int ipv6_rthdr_rcv(struct sk_buff *skb)
344{
345 struct inet6_skb_parm *opt = IP6CB(skb);
346 struct in6_addr *addr = NULL;
347 struct in6_addr daddr;
348 struct inet6_dev *idev;
349 int n, i;
350 struct ipv6_rt_hdr *hdr;
351 struct rt0_hdr *rthdr;
352 struct net *net = dev_net(skb->dev);
353 int accept_source_route = net->ipv6.devconf_all->accept_source_route;
354
355 idev = __in6_dev_get(skb->dev);
356 if (idev && accept_source_route > idev->cnf.accept_source_route)
357 accept_source_route = idev->cnf.accept_source_route;
358
359 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
360 !pskb_may_pull(skb, (skb_transport_offset(skb) +
361 ((skb_transport_header(skb)[1] + 1) << 3)))) {
362 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
363 IPSTATS_MIB_INHDRERRORS);
364 kfree_skb(skb);
365 return -1;
366 }
367
368 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
369
370 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
371 skb->pkt_type != PACKET_HOST) {
372 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
373 IPSTATS_MIB_INADDRERRORS);
374 kfree_skb(skb);
375 return -1;
376 }
377
378looped_back:
379 if (hdr->segments_left == 0) {
380 switch (hdr->type) {
381#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
382 case IPV6_SRCRT_TYPE_2:
383 /* Silently discard type 2 header unless it was
384 * processed by own
385 */
386 if (!addr) {
387 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
388 IPSTATS_MIB_INADDRERRORS);
389 kfree_skb(skb);
390 return -1;
391 }
392 break;
393#endif
394 default:
395 break;
396 }
397
398 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
399 skb->transport_header += (hdr->hdrlen + 1) << 3;
400 opt->dst0 = opt->dst1;
401 opt->dst1 = 0;
402 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
403 return 1;
404 }
405
406 switch (hdr->type) {
407#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
408 case IPV6_SRCRT_TYPE_2:
409 if (accept_source_route < 0)
410 goto unknown_rh;
411 /* Silently discard invalid RTH type 2 */
412 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
413 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
414 IPSTATS_MIB_INHDRERRORS);
415 kfree_skb(skb);
416 return -1;
417 }
418 break;
419#endif
420 default:
421 goto unknown_rh;
422 }
423
424 /*
425 * This is the routing header forwarding algorithm from
426 * RFC 2460, page 16.
427 */
428
429 n = hdr->hdrlen >> 1;
430
431 if (hdr->segments_left > n) {
432 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
433 IPSTATS_MIB_INHDRERRORS);
434 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
435 ((&hdr->segments_left) -
436 skb_network_header(skb)));
437 return -1;
438 }
439
440 /* We are about to mangle packet header. Be careful!
441 Do not damage packets queued somewhere.
442 */
443 if (skb_cloned(skb)) {
444 /* the copy is a forwarded packet */
445 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
446 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
447 IPSTATS_MIB_OUTDISCARDS);
448 kfree_skb(skb);
449 return -1;
450 }
451 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
452 }
453
454 if (skb->ip_summed == CHECKSUM_COMPLETE)
455 skb->ip_summed = CHECKSUM_NONE;
456
457 i = n - --hdr->segments_left;
458
459 rthdr = (struct rt0_hdr *) hdr;
460 addr = rthdr->addr;
461 addr += i - 1;
462
463 switch (hdr->type) {
464#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
465 case IPV6_SRCRT_TYPE_2:
466 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
467 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
468 IPPROTO_ROUTING) < 0) {
469 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
470 IPSTATS_MIB_INADDRERRORS);
471 kfree_skb(skb);
472 return -1;
473 }
474 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
475 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
476 IPSTATS_MIB_INADDRERRORS);
477 kfree_skb(skb);
478 return -1;
479 }
480 break;
481#endif
482 default:
483 break;
484 }
485
486 if (ipv6_addr_is_multicast(addr)) {
487 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
488 IPSTATS_MIB_INADDRERRORS);
489 kfree_skb(skb);
490 return -1;
491 }
492
493 daddr = *addr;
494 *addr = ipv6_hdr(skb)->daddr;
495 ipv6_hdr(skb)->daddr = daddr;
496
497 skb_dst_drop(skb);
498 ip6_route_input(skb);
499 if (skb_dst(skb)->error) {
500 skb_push(skb, skb->data - skb_network_header(skb));
501 dst_input(skb);
502 return -1;
503 }
504
505 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
506 if (ipv6_hdr(skb)->hop_limit <= 1) {
507 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
508 IPSTATS_MIB_INHDRERRORS);
509 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
510 0);
511 kfree_skb(skb);
512 return -1;
513 }
514 ipv6_hdr(skb)->hop_limit--;
515 goto looped_back;
516 }
517
518 skb_push(skb, skb->data - skb_network_header(skb));
519 dst_input(skb);
520 return -1;
521
522unknown_rh:
523 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
524 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
525 (&hdr->type) - skb_network_header(skb));
526 return -1;
527}
528
529static const struct inet6_protocol rthdr_protocol = {
530 .handler = ipv6_rthdr_rcv,
531 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
532};
533
534static const struct inet6_protocol destopt_protocol = {
535 .handler = ipv6_destopt_rcv,
536 .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
537};
538
539static const struct inet6_protocol nodata_protocol = {
540 .handler = dst_discard,
541 .flags = INET6_PROTO_NOPOLICY,
542};
543
544int __init ipv6_exthdrs_init(void)
545{
546 int ret;
547
548 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
549 if (ret)
550 goto out;
551
552 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
553 if (ret)
554 goto out_rthdr;
555
556 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
557 if (ret)
558 goto out_destopt;
559
560out:
561 return ret;
562out_rthdr:
563 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
564out_destopt:
565 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
566 goto out;
567};
568
569void ipv6_exthdrs_exit(void)
570{
571 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
572 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
573 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
574}
575
576/**********************************
577 Hop-by-hop options.
578 **********************************/
579
580/*
581 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
582 */
583static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
584{
585 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
586}
587
588static inline struct net *ipv6_skb_net(struct sk_buff *skb)
589{
590 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
591}
592
593/* Router Alert as of RFC 2711 */
594
595static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
596{
597 const unsigned char *nh = skb_network_header(skb);
598
599 if (nh[optoff + 1] == 2) {
600 IP6CB(skb)->ra = optoff;
601 return true;
602 }
603 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
604 nh[optoff + 1]);
605 kfree_skb(skb);
606 return false;
607}
608
609/* Jumbo payload */
610
611static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
612{
613 const unsigned char *nh = skb_network_header(skb);
614 struct net *net = ipv6_skb_net(skb);
615 u32 pkt_len;
616
617 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
618 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
619 nh[optoff+1]);
620 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
621 IPSTATS_MIB_INHDRERRORS);
622 goto drop;
623 }
624
625 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
626 if (pkt_len <= IPV6_MAXPLEN) {
627 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
628 IPSTATS_MIB_INHDRERRORS);
629 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
630 return false;
631 }
632 if (ipv6_hdr(skb)->payload_len) {
633 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
634 IPSTATS_MIB_INHDRERRORS);
635 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
636 return false;
637 }
638
639 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
640 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
641 IPSTATS_MIB_INTRUNCATEDPKTS);
642 goto drop;
643 }
644
645 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
646 goto drop;
647
648 return true;
649
650drop:
651 kfree_skb(skb);
652 return false;
653}
654
655static const struct tlvtype_proc tlvprochopopt_lst[] = {
656 {
657 .type = IPV6_TLV_ROUTERALERT,
658 .func = ipv6_hop_ra,
659 },
660 {
661 .type = IPV6_TLV_JUMBO,
662 .func = ipv6_hop_jumbo,
663 },
664 { -1, }
665};
666
667int ipv6_parse_hopopts(struct sk_buff *skb)
668{
669 struct inet6_skb_parm *opt = IP6CB(skb);
670
671 /*
672 * skb_network_header(skb) is equal to skb->data, and
673 * skb_network_header_len(skb) is always equal to
674 * sizeof(struct ipv6hdr) by definition of
675 * hop-by-hop options.
676 */
677 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
678 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
679 ((skb_transport_header(skb)[1] + 1) << 3)))) {
680 kfree_skb(skb);
681 return -1;
682 }
683
684 opt->hop = sizeof(struct ipv6hdr);
685 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
686 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
687 opt = IP6CB(skb);
688 opt->nhoff = sizeof(struct ipv6hdr);
689 return 1;
690 }
691 return -1;
692}
693
694/*
695 * Creating outbound headers.
696 *
697 * "build" functions work when skb is filled from head to tail (datagram)
698 * "push" functions work when headers are added from tail to head (tcp)
699 *
700 * In both cases we assume, that caller reserved enough room
701 * for headers.
702 */
703
704static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
705 struct ipv6_rt_hdr *opt,
706 struct in6_addr **addr_p)
707{
708 struct rt0_hdr *phdr, *ihdr;
709 int hops;
710
711 ihdr = (struct rt0_hdr *) opt;
712
713 phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
714 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
715
716 hops = ihdr->rt_hdr.hdrlen >> 1;
717
718 if (hops > 1)
719 memcpy(phdr->addr, ihdr->addr + 1,
720 (hops - 1) * sizeof(struct in6_addr));
721
722 phdr->addr[hops - 1] = **addr_p;
723 *addr_p = ihdr->addr;
724
725 phdr->rt_hdr.nexthdr = *proto;
726 *proto = NEXTHDR_ROUTING;
727}
728
729static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
730{
731 struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
732
733 memcpy(h, opt, ipv6_optlen(opt));
734 h->nexthdr = *proto;
735 *proto = type;
736}
737
738void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
739 u8 *proto,
740 struct in6_addr **daddr)
741{
742 if (opt->srcrt) {
743 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
744 /*
745 * IPV6_RTHDRDSTOPTS is ignored
746 * unless IPV6_RTHDR is set (RFC3542).
747 */
748 if (opt->dst0opt)
749 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
750 }
751 if (opt->hopopt)
752 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
753}
754EXPORT_SYMBOL(ipv6_push_nfrag_opts);
755
756void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
757{
758 if (opt->dst1opt)
759 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
760}
761
762struct ipv6_txoptions *
763ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
764{
765 struct ipv6_txoptions *opt2;
766
767 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
768 if (opt2) {
769 long dif = (char *)opt2 - (char *)opt;
770 memcpy(opt2, opt, opt->tot_len);
771 if (opt2->hopopt)
772 *((char **)&opt2->hopopt) += dif;
773 if (opt2->dst0opt)
774 *((char **)&opt2->dst0opt) += dif;
775 if (opt2->dst1opt)
776 *((char **)&opt2->dst1opt) += dif;
777 if (opt2->srcrt)
778 *((char **)&opt2->srcrt) += dif;
779 }
780 return opt2;
781}
782EXPORT_SYMBOL_GPL(ipv6_dup_options);
783
784static int ipv6_renew_option(void *ohdr,
785 struct ipv6_opt_hdr __user *newopt, int newoptlen,
786 int inherit,
787 struct ipv6_opt_hdr **hdr,
788 char **p)
789{
790 if (inherit) {
791 if (ohdr) {
792 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
793 *hdr = (struct ipv6_opt_hdr *)*p;
794 *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
795 }
796 } else {
797 if (newopt) {
798 if (copy_from_user(*p, newopt, newoptlen))
799 return -EFAULT;
800 *hdr = (struct ipv6_opt_hdr *)*p;
801 if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
802 return -EINVAL;
803 *p += CMSG_ALIGN(newoptlen);
804 }
805 }
806 return 0;
807}
808
809struct ipv6_txoptions *
810ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
811 int newtype,
812 struct ipv6_opt_hdr __user *newopt, int newoptlen)
813{
814 int tot_len = 0;
815 char *p;
816 struct ipv6_txoptions *opt2;
817 int err;
818
819 if (opt) {
820 if (newtype != IPV6_HOPOPTS && opt->hopopt)
821 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
822 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
823 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
824 if (newtype != IPV6_RTHDR && opt->srcrt)
825 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
826 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
827 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
828 }
829
830 if (newopt && newoptlen)
831 tot_len += CMSG_ALIGN(newoptlen);
832
833 if (!tot_len)
834 return NULL;
835
836 tot_len += sizeof(*opt2);
837 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
838 if (!opt2)
839 return ERR_PTR(-ENOBUFS);
840
841 memset(opt2, 0, tot_len);
842
843 opt2->tot_len = tot_len;
844 p = (char *)(opt2 + 1);
845
846 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
847 newtype != IPV6_HOPOPTS,
848 &opt2->hopopt, &p);
849 if (err)
850 goto out;
851
852 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
853 newtype != IPV6_RTHDRDSTOPTS,
854 &opt2->dst0opt, &p);
855 if (err)
856 goto out;
857
858 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
859 newtype != IPV6_RTHDR,
860 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
861 if (err)
862 goto out;
863
864 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
865 newtype != IPV6_DSTOPTS,
866 &opt2->dst1opt, &p);
867 if (err)
868 goto out;
869
870 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
871 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
872 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
873 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
874
875 return opt2;
876out:
877 sock_kfree_s(sk, opt2, opt2->tot_len);
878 return ERR_PTR(err);
879}
880
881struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
882 struct ipv6_txoptions *opt)
883{
884 /*
885 * ignore the dest before srcrt unless srcrt is being included.
886 * --yoshfuji
887 */
888 if (opt && opt->dst0opt && !opt->srcrt) {
889 if (opt_space != opt) {
890 memcpy(opt_space, opt, sizeof(*opt_space));
891 opt = opt_space;
892 }
893 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
894 opt->dst0opt = NULL;
895 }
896
897 return opt;
898}
899EXPORT_SYMBOL_GPL(ipv6_fixup_options);
900
901/**
902 * fl6_update_dst - update flowi destination address with info given
903 * by srcrt option, if any.
904 *
905 * @fl6: flowi6 for which daddr is to be updated
906 * @opt: struct ipv6_txoptions in which to look for srcrt opt
907 * @orig: copy of original daddr address if modified
908 *
909 * Returns NULL if no txoptions or no srcrt, otherwise returns orig
910 * and initial value of fl6->daddr set in orig
911 */
912struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
913 const struct ipv6_txoptions *opt,
914 struct in6_addr *orig)
915{
916 if (!opt || !opt->srcrt)
917 return NULL;
918
919 *orig = fl6->daddr;
920 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
921 return orig;
922}
923EXPORT_SYMBOL_GPL(fl6_update_dst);