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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Extension Header handling for IPv6
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 * Andi Kleen <ak@muc.de>
9 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
10 */
11
12/* Changes:
13 * yoshfuji : ensure not to overrun while parsing
14 * tlv options.
15 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
16 * YOSHIFUJI Hideaki @USAGI Register inbound extension header
17 * handlers as inet6_protocol{}.
18 */
19
20#include <linux/errno.h>
21#include <linux/types.h>
22#include <linux/socket.h>
23#include <linux/sockios.h>
24#include <linux/net.h>
25#include <linux/netdevice.h>
26#include <linux/in6.h>
27#include <linux/icmpv6.h>
28#include <linux/slab.h>
29#include <linux/export.h>
30
31#include <net/dst.h>
32#include <net/sock.h>
33#include <net/snmp.h>
34
35#include <net/ipv6.h>
36#include <net/protocol.h>
37#include <net/transp_v6.h>
38#include <net/rawv6.h>
39#include <net/ndisc.h>
40#include <net/ip6_route.h>
41#include <net/addrconf.h>
42#include <net/calipso.h>
43#if IS_ENABLED(CONFIG_IPV6_MIP6)
44#include <net/xfrm.h>
45#endif
46#include <linux/seg6.h>
47#include <net/seg6.h>
48#ifdef CONFIG_IPV6_SEG6_HMAC
49#include <net/seg6_hmac.h>
50#endif
51#include <net/rpl.h>
52#include <linux/ioam6.h>
53#include <linux/ioam6_genl.h>
54#include <net/ioam6.h>
55#include <net/dst_metadata.h>
56
57#include <linux/uaccess.h>
58
59/*********************
60 Generic functions
61 *********************/
62
63/* An unknown option is detected, decide what to do */
64
65static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
66 bool disallow_unknowns)
67{
68 if (disallow_unknowns) {
69 /* If unknown TLVs are disallowed by configuration
70 * then always silently drop packet. Note this also
71 * means no ICMP parameter problem is sent which
72 * could be a good property to mitigate a reflection DOS
73 * attack.
74 */
75
76 goto drop;
77 }
78
79 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
80 case 0: /* ignore */
81 return true;
82
83 case 1: /* drop packet */
84 break;
85
86 case 3: /* Send ICMP if not a multicast address and drop packet */
87 /* Actually, it is redundant check. icmp_send
88 will recheck in any case.
89 */
90 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
91 break;
92 fallthrough;
93 case 2: /* send ICMP PARM PROB regardless and drop packet */
94 icmpv6_param_prob_reason(skb, ICMPV6_UNK_OPTION, optoff,
95 SKB_DROP_REASON_UNHANDLED_PROTO);
96 return false;
97 }
98
99drop:
100 kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO);
101 return false;
102}
103
104static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
105static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
106static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
107static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
108#if IS_ENABLED(CONFIG_IPV6_MIP6)
109static bool ipv6_dest_hao(struct sk_buff *skb, int optoff);
110#endif
111
112/* Parse tlv encoded option header (hop-by-hop or destination) */
113
114static bool ip6_parse_tlv(bool hopbyhop,
115 struct sk_buff *skb,
116 int max_count)
117{
118 int len = (skb_transport_header(skb)[1] + 1) << 3;
119 const unsigned char *nh = skb_network_header(skb);
120 int off = skb_network_header_len(skb);
121 bool disallow_unknowns = false;
122 int tlv_count = 0;
123 int padlen = 0;
124
125 if (unlikely(max_count < 0)) {
126 disallow_unknowns = true;
127 max_count = -max_count;
128 }
129
130 off += 2;
131 len -= 2;
132
133 while (len > 0) {
134 int optlen, i;
135
136 if (nh[off] == IPV6_TLV_PAD1) {
137 padlen++;
138 if (padlen > 7)
139 goto bad;
140 off++;
141 len--;
142 continue;
143 }
144 if (len < 2)
145 goto bad;
146 optlen = nh[off + 1] + 2;
147 if (optlen > len)
148 goto bad;
149
150 if (nh[off] == IPV6_TLV_PADN) {
151 /* RFC 2460 states that the purpose of PadN is
152 * to align the containing header to multiples
153 * of 8. 7 is therefore the highest valid value.
154 * See also RFC 4942, Section 2.1.9.5.
155 */
156 padlen += optlen;
157 if (padlen > 7)
158 goto bad;
159 /* RFC 4942 recommends receiving hosts to
160 * actively check PadN payload to contain
161 * only zeroes.
162 */
163 for (i = 2; i < optlen; i++) {
164 if (nh[off + i] != 0)
165 goto bad;
166 }
167 } else {
168 tlv_count++;
169 if (tlv_count > max_count)
170 goto bad;
171
172 if (hopbyhop) {
173 switch (nh[off]) {
174 case IPV6_TLV_ROUTERALERT:
175 if (!ipv6_hop_ra(skb, off))
176 return false;
177 break;
178 case IPV6_TLV_IOAM:
179 if (!ipv6_hop_ioam(skb, off))
180 return false;
181
182 nh = skb_network_header(skb);
183 break;
184 case IPV6_TLV_JUMBO:
185 if (!ipv6_hop_jumbo(skb, off))
186 return false;
187 break;
188 case IPV6_TLV_CALIPSO:
189 if (!ipv6_hop_calipso(skb, off))
190 return false;
191 break;
192 default:
193 if (!ip6_tlvopt_unknown(skb, off,
194 disallow_unknowns))
195 return false;
196 break;
197 }
198 } else {
199 switch (nh[off]) {
200#if IS_ENABLED(CONFIG_IPV6_MIP6)
201 case IPV6_TLV_HAO:
202 if (!ipv6_dest_hao(skb, off))
203 return false;
204 break;
205#endif
206 default:
207 if (!ip6_tlvopt_unknown(skb, off,
208 disallow_unknowns))
209 return false;
210 break;
211 }
212 }
213 padlen = 0;
214 }
215 off += optlen;
216 len -= optlen;
217 }
218
219 if (len == 0)
220 return true;
221bad:
222 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
223 return false;
224}
225
226/*****************************
227 Destination options header.
228 *****************************/
229
230#if IS_ENABLED(CONFIG_IPV6_MIP6)
231static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
232{
233 struct ipv6_destopt_hao *hao;
234 struct inet6_skb_parm *opt = IP6CB(skb);
235 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
236 SKB_DR(reason);
237 int ret;
238
239 if (opt->dsthao) {
240 net_dbg_ratelimited("hao duplicated\n");
241 goto discard;
242 }
243 opt->dsthao = opt->dst1;
244 opt->dst1 = 0;
245
246 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
247
248 if (hao->length != 16) {
249 net_dbg_ratelimited("hao invalid option length = %d\n",
250 hao->length);
251 SKB_DR_SET(reason, IP_INHDR);
252 goto discard;
253 }
254
255 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
256 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
257 &hao->addr);
258 SKB_DR_SET(reason, INVALID_PROTO);
259 goto discard;
260 }
261
262 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
263 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
264 if (unlikely(ret < 0)) {
265 SKB_DR_SET(reason, XFRM_POLICY);
266 goto discard;
267 }
268
269 if (skb_cloned(skb)) {
270 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
271 goto discard;
272
273 /* update all variable using below by copied skbuff */
274 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
275 optoff);
276 ipv6h = ipv6_hdr(skb);
277 }
278
279 if (skb->ip_summed == CHECKSUM_COMPLETE)
280 skb->ip_summed = CHECKSUM_NONE;
281
282 swap(ipv6h->saddr, hao->addr);
283
284 if (skb->tstamp == 0)
285 __net_timestamp(skb);
286
287 return true;
288
289 discard:
290 kfree_skb_reason(skb, reason);
291 return false;
292}
293#endif
294
295static int ipv6_destopt_rcv(struct sk_buff *skb)
296{
297 struct inet6_dev *idev = __in6_dev_get(skb->dev);
298 struct inet6_skb_parm *opt = IP6CB(skb);
299#if IS_ENABLED(CONFIG_IPV6_MIP6)
300 __u16 dstbuf;
301#endif
302 struct dst_entry *dst = skb_dst(skb);
303 struct net *net = dev_net(skb->dev);
304 int extlen;
305
306 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
307 !pskb_may_pull(skb, (skb_transport_offset(skb) +
308 ((skb_transport_header(skb)[1] + 1) << 3)))) {
309 __IP6_INC_STATS(dev_net(dst->dev), idev,
310 IPSTATS_MIB_INHDRERRORS);
311fail_and_free:
312 kfree_skb(skb);
313 return -1;
314 }
315
316 extlen = (skb_transport_header(skb)[1] + 1) << 3;
317 if (extlen > net->ipv6.sysctl.max_dst_opts_len)
318 goto fail_and_free;
319
320 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
321#if IS_ENABLED(CONFIG_IPV6_MIP6)
322 dstbuf = opt->dst1;
323#endif
324
325 if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) {
326 skb->transport_header += extlen;
327 opt = IP6CB(skb);
328#if IS_ENABLED(CONFIG_IPV6_MIP6)
329 opt->nhoff = dstbuf;
330#else
331 opt->nhoff = opt->dst1;
332#endif
333 return 1;
334 }
335
336 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
337 return -1;
338}
339
340static void seg6_update_csum(struct sk_buff *skb)
341{
342 struct ipv6_sr_hdr *hdr;
343 struct in6_addr *addr;
344 __be32 from, to;
345
346 /* srh is at transport offset and seg_left is already decremented
347 * but daddr is not yet updated with next segment
348 */
349
350 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
351 addr = hdr->segments + hdr->segments_left;
352
353 hdr->segments_left++;
354 from = *(__be32 *)hdr;
355
356 hdr->segments_left--;
357 to = *(__be32 *)hdr;
358
359 /* update skb csum with diff resulting from seg_left decrement */
360
361 update_csum_diff4(skb, from, to);
362
363 /* compute csum diff between current and next segment and update */
364
365 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
366 (__be32 *)addr);
367}
368
369static int ipv6_srh_rcv(struct sk_buff *skb)
370{
371 struct inet6_skb_parm *opt = IP6CB(skb);
372 struct net *net = dev_net(skb->dev);
373 struct ipv6_sr_hdr *hdr;
374 struct inet6_dev *idev;
375 struct in6_addr *addr;
376 int accept_seg6;
377
378 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
379
380 idev = __in6_dev_get(skb->dev);
381
382 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled),
383 READ_ONCE(idev->cnf.seg6_enabled));
384
385 if (!accept_seg6) {
386 kfree_skb(skb);
387 return -1;
388 }
389
390#ifdef CONFIG_IPV6_SEG6_HMAC
391 if (!seg6_hmac_validate_skb(skb)) {
392 kfree_skb(skb);
393 return -1;
394 }
395#endif
396
397looped_back:
398 if (hdr->segments_left == 0) {
399 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
400 int offset = (hdr->hdrlen + 1) << 3;
401
402 skb_postpull_rcsum(skb, skb_network_header(skb),
403 skb_network_header_len(skb));
404 skb_pull(skb, offset);
405 skb_postpull_rcsum(skb, skb_transport_header(skb),
406 offset);
407
408 skb_reset_network_header(skb);
409 skb_reset_transport_header(skb);
410 skb->encapsulation = 0;
411 if (hdr->nexthdr == NEXTHDR_IPV4)
412 skb->protocol = htons(ETH_P_IP);
413 __skb_tunnel_rx(skb, skb->dev, net);
414
415 netif_rx(skb);
416 return -1;
417 }
418
419 opt->srcrt = skb_network_header_len(skb);
420 opt->lastopt = opt->srcrt;
421 skb->transport_header += (hdr->hdrlen + 1) << 3;
422 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
423
424 return 1;
425 }
426
427 if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
428 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
429 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
430 ((&hdr->segments_left) -
431 skb_network_header(skb)));
432 return -1;
433 }
434
435 if (skb_cloned(skb)) {
436 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
437 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
438 IPSTATS_MIB_OUTDISCARDS);
439 kfree_skb(skb);
440 return -1;
441 }
442
443 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
444 }
445
446 hdr->segments_left--;
447 addr = hdr->segments + hdr->segments_left;
448
449 skb_push(skb, sizeof(struct ipv6hdr));
450
451 if (skb->ip_summed == CHECKSUM_COMPLETE)
452 seg6_update_csum(skb);
453
454 ipv6_hdr(skb)->daddr = *addr;
455
456 ip6_route_input(skb);
457
458 if (skb_dst(skb)->error) {
459 dst_input(skb);
460 return -1;
461 }
462
463 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
464 if (ipv6_hdr(skb)->hop_limit <= 1) {
465 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
466 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
467 ICMPV6_EXC_HOPLIMIT, 0);
468 kfree_skb(skb);
469 return -1;
470 }
471 ipv6_hdr(skb)->hop_limit--;
472
473 skb_pull(skb, sizeof(struct ipv6hdr));
474 goto looped_back;
475 }
476
477 dst_input(skb);
478
479 return -1;
480}
481
482static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
483{
484 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
485 struct inet6_skb_parm *opt = IP6CB(skb);
486 struct net *net = dev_net(skb->dev);
487 struct inet6_dev *idev;
488 struct ipv6hdr *oldhdr;
489 unsigned char *buf;
490 int accept_rpl_seg;
491 int i, err;
492 u64 n = 0;
493 u32 r;
494
495 idev = __in6_dev_get(skb->dev);
496
497 accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
498 if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
499 accept_rpl_seg = idev->cnf.rpl_seg_enabled;
500
501 if (!accept_rpl_seg) {
502 kfree_skb(skb);
503 return -1;
504 }
505
506looped_back:
507 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
508
509 if (hdr->segments_left == 0) {
510 if (hdr->nexthdr == NEXTHDR_IPV6) {
511 int offset = (hdr->hdrlen + 1) << 3;
512
513 skb_postpull_rcsum(skb, skb_network_header(skb),
514 skb_network_header_len(skb));
515 skb_pull(skb, offset);
516 skb_postpull_rcsum(skb, skb_transport_header(skb),
517 offset);
518
519 skb_reset_network_header(skb);
520 skb_reset_transport_header(skb);
521 skb->encapsulation = 0;
522
523 __skb_tunnel_rx(skb, skb->dev, net);
524
525 netif_rx(skb);
526 return -1;
527 }
528
529 opt->srcrt = skb_network_header_len(skb);
530 opt->lastopt = opt->srcrt;
531 skb->transport_header += (hdr->hdrlen + 1) << 3;
532 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
533
534 return 1;
535 }
536
537 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
538 r = do_div(n, (16 - hdr->cmpri));
539 /* checks if calculation was without remainder and n fits into
540 * unsigned char which is segments_left field. Should not be
541 * higher than that.
542 */
543 if (r || (n + 1) > 255) {
544 kfree_skb(skb);
545 return -1;
546 }
547
548 if (hdr->segments_left > n + 1) {
549 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
550 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
551 ((&hdr->segments_left) -
552 skb_network_header(skb)));
553 return -1;
554 }
555
556 hdr->segments_left--;
557 i = n - hdr->segments_left;
558
559 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
560 if (unlikely(!buf)) {
561 kfree_skb(skb);
562 return -1;
563 }
564
565 ohdr = (struct ipv6_rpl_sr_hdr *)buf;
566 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
567 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
568
569 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
570 kfree_skb(skb);
571 kfree(buf);
572 return -1;
573 }
574
575 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
576 if (err) {
577 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
578 kfree_skb(skb);
579 kfree(buf);
580 return -1;
581 }
582
583 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
584
585 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
586
587 oldhdr = ipv6_hdr(skb);
588
589 skb_pull(skb, ((hdr->hdrlen + 1) << 3));
590 skb_postpull_rcsum(skb, oldhdr,
591 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
592 if (unlikely(!hdr->segments_left)) {
593 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
594 GFP_ATOMIC)) {
595 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
596 kfree_skb(skb);
597 kfree(buf);
598 return -1;
599 }
600
601 oldhdr = ipv6_hdr(skb);
602 }
603 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
604 skb_reset_network_header(skb);
605 skb_mac_header_rebuild(skb);
606 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
607
608 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
609 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
610
611 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
612 skb_postpush_rcsum(skb, ipv6_hdr(skb),
613 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
614
615 kfree(buf);
616
617 ip6_route_input(skb);
618
619 if (skb_dst(skb)->error) {
620 dst_input(skb);
621 return -1;
622 }
623
624 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
625 if (ipv6_hdr(skb)->hop_limit <= 1) {
626 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
627 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
628 ICMPV6_EXC_HOPLIMIT, 0);
629 kfree_skb(skb);
630 return -1;
631 }
632 ipv6_hdr(skb)->hop_limit--;
633
634 skb_pull(skb, sizeof(struct ipv6hdr));
635 goto looped_back;
636 }
637
638 dst_input(skb);
639
640 return -1;
641}
642
643/********************************
644 Routing header.
645 ********************************/
646
647/* called with rcu_read_lock() */
648static int ipv6_rthdr_rcv(struct sk_buff *skb)
649{
650 struct inet6_dev *idev = __in6_dev_get(skb->dev);
651 struct inet6_skb_parm *opt = IP6CB(skb);
652 struct in6_addr *addr = NULL;
653 int n, i;
654 struct ipv6_rt_hdr *hdr;
655 struct rt0_hdr *rthdr;
656 struct net *net = dev_net(skb->dev);
657 int accept_source_route;
658
659 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
660
661 if (idev)
662 accept_source_route = min(accept_source_route,
663 READ_ONCE(idev->cnf.accept_source_route));
664
665 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
666 !pskb_may_pull(skb, (skb_transport_offset(skb) +
667 ((skb_transport_header(skb)[1] + 1) << 3)))) {
668 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
669 kfree_skb(skb);
670 return -1;
671 }
672
673 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
674
675 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
676 skb->pkt_type != PACKET_HOST) {
677 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
678 kfree_skb(skb);
679 return -1;
680 }
681
682 switch (hdr->type) {
683 case IPV6_SRCRT_TYPE_4:
684 /* segment routing */
685 return ipv6_srh_rcv(skb);
686 case IPV6_SRCRT_TYPE_3:
687 /* rpl segment routing */
688 return ipv6_rpl_srh_rcv(skb);
689 default:
690 break;
691 }
692
693looped_back:
694 if (hdr->segments_left == 0) {
695 switch (hdr->type) {
696#if IS_ENABLED(CONFIG_IPV6_MIP6)
697 case IPV6_SRCRT_TYPE_2:
698 /* Silently discard type 2 header unless it was
699 * processed by own
700 */
701 if (!addr) {
702 __IP6_INC_STATS(net, idev,
703 IPSTATS_MIB_INADDRERRORS);
704 kfree_skb(skb);
705 return -1;
706 }
707 break;
708#endif
709 default:
710 break;
711 }
712
713 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
714 skb->transport_header += (hdr->hdrlen + 1) << 3;
715 opt->dst0 = opt->dst1;
716 opt->dst1 = 0;
717 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
718 return 1;
719 }
720
721 switch (hdr->type) {
722#if IS_ENABLED(CONFIG_IPV6_MIP6)
723 case IPV6_SRCRT_TYPE_2:
724 if (accept_source_route < 0)
725 goto unknown_rh;
726 /* Silently discard invalid RTH type 2 */
727 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
728 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
729 kfree_skb(skb);
730 return -1;
731 }
732 break;
733#endif
734 default:
735 goto unknown_rh;
736 }
737
738 /*
739 * This is the routing header forwarding algorithm from
740 * RFC 2460, page 16.
741 */
742
743 n = hdr->hdrlen >> 1;
744
745 if (hdr->segments_left > n) {
746 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
747 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
748 ((&hdr->segments_left) -
749 skb_network_header(skb)));
750 return -1;
751 }
752
753 /* We are about to mangle packet header. Be careful!
754 Do not damage packets queued somewhere.
755 */
756 if (skb_cloned(skb)) {
757 /* the copy is a forwarded packet */
758 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
759 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
760 IPSTATS_MIB_OUTDISCARDS);
761 kfree_skb(skb);
762 return -1;
763 }
764 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
765 }
766
767 if (skb->ip_summed == CHECKSUM_COMPLETE)
768 skb->ip_summed = CHECKSUM_NONE;
769
770 i = n - --hdr->segments_left;
771
772 rthdr = (struct rt0_hdr *) hdr;
773 addr = rthdr->addr;
774 addr += i - 1;
775
776 switch (hdr->type) {
777#if IS_ENABLED(CONFIG_IPV6_MIP6)
778 case IPV6_SRCRT_TYPE_2:
779 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
780 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
781 IPPROTO_ROUTING) < 0) {
782 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
783 kfree_skb(skb);
784 return -1;
785 }
786 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
787 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
788 kfree_skb(skb);
789 return -1;
790 }
791 break;
792#endif
793 default:
794 break;
795 }
796
797 if (ipv6_addr_is_multicast(addr)) {
798 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
799 kfree_skb(skb);
800 return -1;
801 }
802
803 swap(*addr, ipv6_hdr(skb)->daddr);
804
805 ip6_route_input(skb);
806 if (skb_dst(skb)->error) {
807 skb_push(skb, -skb_network_offset(skb));
808 dst_input(skb);
809 return -1;
810 }
811
812 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
813 if (ipv6_hdr(skb)->hop_limit <= 1) {
814 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
815 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
816 0);
817 kfree_skb(skb);
818 return -1;
819 }
820 ipv6_hdr(skb)->hop_limit--;
821 goto looped_back;
822 }
823
824 skb_push(skb, -skb_network_offset(skb));
825 dst_input(skb);
826 return -1;
827
828unknown_rh:
829 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
830 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
831 (&hdr->type) - skb_network_header(skb));
832 return -1;
833}
834
835static const struct inet6_protocol rthdr_protocol = {
836 .handler = ipv6_rthdr_rcv,
837 .flags = INET6_PROTO_NOPOLICY,
838};
839
840static const struct inet6_protocol destopt_protocol = {
841 .handler = ipv6_destopt_rcv,
842 .flags = INET6_PROTO_NOPOLICY,
843};
844
845static const struct inet6_protocol nodata_protocol = {
846 .handler = dst_discard,
847 .flags = INET6_PROTO_NOPOLICY,
848};
849
850int __init ipv6_exthdrs_init(void)
851{
852 int ret;
853
854 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
855 if (ret)
856 goto out;
857
858 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
859 if (ret)
860 goto out_rthdr;
861
862 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
863 if (ret)
864 goto out_destopt;
865
866out:
867 return ret;
868out_destopt:
869 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
870out_rthdr:
871 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
872 goto out;
873};
874
875void ipv6_exthdrs_exit(void)
876{
877 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
878 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
879 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
880}
881
882/**********************************
883 Hop-by-hop options.
884 **********************************/
885
886/* Router Alert as of RFC 2711 */
887
888static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
889{
890 const unsigned char *nh = skb_network_header(skb);
891
892 if (nh[optoff + 1] == 2) {
893 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
894 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
895 return true;
896 }
897 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
898 nh[optoff + 1]);
899 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
900 return false;
901}
902
903/* IOAM */
904
905static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
906{
907 struct ioam6_trace_hdr *trace;
908 struct ioam6_namespace *ns;
909 struct ioam6_hdr *hdr;
910
911 /* Bad alignment (must be 4n-aligned) */
912 if (optoff & 3)
913 goto drop;
914
915 /* Ignore if IOAM is not enabled on ingress */
916 if (!READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_enabled))
917 goto ignore;
918
919 /* Truncated Option header */
920 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
921 if (hdr->opt_len < 2)
922 goto drop;
923
924 switch (hdr->type) {
925 case IOAM6_TYPE_PREALLOC:
926 /* Truncated Pre-allocated Trace header */
927 if (hdr->opt_len < 2 + sizeof(*trace))
928 goto drop;
929
930 /* Malformed Pre-allocated Trace header */
931 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
932 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
933 goto drop;
934
935 /* Ignore if the IOAM namespace is unknown */
936 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id);
937 if (!ns)
938 goto ignore;
939
940 if (!skb_valid_dst(skb))
941 ip6_route_input(skb);
942
943 /* About to mangle packet header */
944 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
945 goto drop;
946
947 /* Trace pointer may have changed */
948 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb)
949 + optoff + sizeof(*hdr));
950
951 ioam6_fill_trace_data(skb, ns, trace, true);
952
953 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev),
954 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2);
955 break;
956 default:
957 break;
958 }
959
960ignore:
961 return true;
962
963drop:
964 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
965 return false;
966}
967
968/* Jumbo payload */
969
970static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
971{
972 const unsigned char *nh = skb_network_header(skb);
973 SKB_DR(reason);
974 u32 pkt_len;
975
976 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
977 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
978 nh[optoff+1]);
979 SKB_DR_SET(reason, IP_INHDR);
980 goto drop;
981 }
982
983 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
984 if (pkt_len <= IPV6_MAXPLEN) {
985 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
986 SKB_DROP_REASON_IP_INHDR);
987 return false;
988 }
989 if (ipv6_hdr(skb)->payload_len) {
990 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
991 SKB_DROP_REASON_IP_INHDR);
992 return false;
993 }
994
995 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
996 SKB_DR_SET(reason, PKT_TOO_SMALL);
997 goto drop;
998 }
999
1000 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1001 goto drop;
1002
1003 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1004 return true;
1005
1006drop:
1007 kfree_skb_reason(skb, reason);
1008 return false;
1009}
1010
1011/* CALIPSO RFC 5570 */
1012
1013static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1014{
1015 const unsigned char *nh = skb_network_header(skb);
1016
1017 if (nh[optoff + 1] < 8)
1018 goto drop;
1019
1020 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1021 goto drop;
1022
1023 if (!calipso_validate(skb, nh + optoff))
1024 goto drop;
1025
1026 return true;
1027
1028drop:
1029 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1030 return false;
1031}
1032
1033int ipv6_parse_hopopts(struct sk_buff *skb)
1034{
1035 struct inet6_skb_parm *opt = IP6CB(skb);
1036 struct net *net = dev_net(skb->dev);
1037 int extlen;
1038
1039 /*
1040 * skb_network_header(skb) is equal to skb->data, and
1041 * skb_network_header_len(skb) is always equal to
1042 * sizeof(struct ipv6hdr) by definition of
1043 * hop-by-hop options.
1044 */
1045 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1046 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1047 ((skb_transport_header(skb)[1] + 1) << 3)))) {
1048fail_and_free:
1049 kfree_skb(skb);
1050 return -1;
1051 }
1052
1053 extlen = (skb_transport_header(skb)[1] + 1) << 3;
1054 if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1055 goto fail_and_free;
1056
1057 opt->flags |= IP6SKB_HOPBYHOP;
1058 if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
1059 skb->transport_header += extlen;
1060 opt = IP6CB(skb);
1061 opt->nhoff = sizeof(struct ipv6hdr);
1062 return 1;
1063 }
1064 return -1;
1065}
1066
1067/*
1068 * Creating outbound headers.
1069 *
1070 * "build" functions work when skb is filled from head to tail (datagram)
1071 * "push" functions work when headers are added from tail to head (tcp)
1072 *
1073 * In both cases we assume, that caller reserved enough room
1074 * for headers.
1075 */
1076
1077static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1078 struct ipv6_rt_hdr *opt,
1079 struct in6_addr **addr_p, struct in6_addr *saddr)
1080{
1081 struct rt0_hdr *phdr, *ihdr;
1082 int hops;
1083
1084 ihdr = (struct rt0_hdr *) opt;
1085
1086 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1087 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1088
1089 hops = ihdr->rt_hdr.hdrlen >> 1;
1090
1091 if (hops > 1)
1092 memcpy(phdr->addr, ihdr->addr + 1,
1093 (hops - 1) * sizeof(struct in6_addr));
1094
1095 phdr->addr[hops - 1] = **addr_p;
1096 *addr_p = ihdr->addr;
1097
1098 phdr->rt_hdr.nexthdr = *proto;
1099 *proto = NEXTHDR_ROUTING;
1100}
1101
1102static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1103 struct ipv6_rt_hdr *opt,
1104 struct in6_addr **addr_p, struct in6_addr *saddr)
1105{
1106 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1107 int plen, hops;
1108
1109 sr_ihdr = (struct ipv6_sr_hdr *)opt;
1110 plen = (sr_ihdr->hdrlen + 1) << 3;
1111
1112 sr_phdr = skb_push(skb, plen);
1113 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1114
1115 hops = sr_ihdr->first_segment + 1;
1116 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1117 (hops - 1) * sizeof(struct in6_addr));
1118
1119 sr_phdr->segments[0] = **addr_p;
1120 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1121
1122 if (sr_ihdr->hdrlen > hops * 2) {
1123 int tlvs_offset, tlvs_length;
1124
1125 tlvs_offset = (1 + hops * 2) << 3;
1126 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1127 memcpy((char *)sr_phdr + tlvs_offset,
1128 (char *)sr_ihdr + tlvs_offset, tlvs_length);
1129 }
1130
1131#ifdef CONFIG_IPV6_SEG6_HMAC
1132 if (sr_has_hmac(sr_phdr)) {
1133 struct net *net = NULL;
1134
1135 if (skb->dev)
1136 net = dev_net(skb->dev);
1137 else if (skb->sk)
1138 net = sock_net(skb->sk);
1139
1140 WARN_ON(!net);
1141
1142 if (net)
1143 seg6_push_hmac(net, saddr, sr_phdr);
1144 }
1145#endif
1146
1147 sr_phdr->nexthdr = *proto;
1148 *proto = NEXTHDR_ROUTING;
1149}
1150
1151static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1152 struct ipv6_rt_hdr *opt,
1153 struct in6_addr **addr_p, struct in6_addr *saddr)
1154{
1155 switch (opt->type) {
1156 case IPV6_SRCRT_TYPE_0:
1157 case IPV6_SRCRT_STRICT:
1158 case IPV6_SRCRT_TYPE_2:
1159 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1160 break;
1161 case IPV6_SRCRT_TYPE_4:
1162 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1163 break;
1164 default:
1165 break;
1166 }
1167}
1168
1169static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1170{
1171 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1172
1173 memcpy(h, opt, ipv6_optlen(opt));
1174 h->nexthdr = *proto;
1175 *proto = type;
1176}
1177
1178void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1179 u8 *proto,
1180 struct in6_addr **daddr, struct in6_addr *saddr)
1181{
1182 if (opt->srcrt) {
1183 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1184 /*
1185 * IPV6_RTHDRDSTOPTS is ignored
1186 * unless IPV6_RTHDR is set (RFC3542).
1187 */
1188 if (opt->dst0opt)
1189 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1190 }
1191 if (opt->hopopt)
1192 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1193}
1194
1195void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1196{
1197 if (opt->dst1opt)
1198 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1199}
1200EXPORT_SYMBOL(ipv6_push_frag_opts);
1201
1202struct ipv6_txoptions *
1203ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1204{
1205 struct ipv6_txoptions *opt2;
1206
1207 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1208 if (opt2) {
1209 long dif = (char *)opt2 - (char *)opt;
1210 memcpy(opt2, opt, opt->tot_len);
1211 if (opt2->hopopt)
1212 *((char **)&opt2->hopopt) += dif;
1213 if (opt2->dst0opt)
1214 *((char **)&opt2->dst0opt) += dif;
1215 if (opt2->dst1opt)
1216 *((char **)&opt2->dst1opt) += dif;
1217 if (opt2->srcrt)
1218 *((char **)&opt2->srcrt) += dif;
1219 refcount_set(&opt2->refcnt, 1);
1220 }
1221 return opt2;
1222}
1223EXPORT_SYMBOL_GPL(ipv6_dup_options);
1224
1225static void ipv6_renew_option(int renewtype,
1226 struct ipv6_opt_hdr **dest,
1227 struct ipv6_opt_hdr *old,
1228 struct ipv6_opt_hdr *new,
1229 int newtype, char **p)
1230{
1231 struct ipv6_opt_hdr *src;
1232
1233 src = (renewtype == newtype ? new : old);
1234 if (!src)
1235 return;
1236
1237 memcpy(*p, src, ipv6_optlen(src));
1238 *dest = (struct ipv6_opt_hdr *)*p;
1239 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1240}
1241
1242/**
1243 * ipv6_renew_options - replace a specific ext hdr with a new one.
1244 *
1245 * @sk: sock from which to allocate memory
1246 * @opt: original options
1247 * @newtype: option type to replace in @opt
1248 * @newopt: new option of type @newtype to replace (user-mem)
1249 *
1250 * Returns a new set of options which is a copy of @opt with the
1251 * option type @newtype replaced with @newopt.
1252 *
1253 * @opt may be NULL, in which case a new set of options is returned
1254 * containing just @newopt.
1255 *
1256 * @newopt may be NULL, in which case the specified option type is
1257 * not copied into the new set of options.
1258 *
1259 * The new set of options is allocated from the socket option memory
1260 * buffer of @sk.
1261 */
1262struct ipv6_txoptions *
1263ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1264 int newtype, struct ipv6_opt_hdr *newopt)
1265{
1266 int tot_len = 0;
1267 char *p;
1268 struct ipv6_txoptions *opt2;
1269
1270 if (opt) {
1271 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1272 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1273 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1274 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1275 if (newtype != IPV6_RTHDR && opt->srcrt)
1276 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1277 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1278 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1279 }
1280
1281 if (newopt)
1282 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1283
1284 if (!tot_len)
1285 return NULL;
1286
1287 tot_len += sizeof(*opt2);
1288 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1289 if (!opt2)
1290 return ERR_PTR(-ENOBUFS);
1291
1292 memset(opt2, 0, tot_len);
1293 refcount_set(&opt2->refcnt, 1);
1294 opt2->tot_len = tot_len;
1295 p = (char *)(opt2 + 1);
1296
1297 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1298 (opt ? opt->hopopt : NULL),
1299 newopt, newtype, &p);
1300 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1301 (opt ? opt->dst0opt : NULL),
1302 newopt, newtype, &p);
1303 ipv6_renew_option(IPV6_RTHDR,
1304 (struct ipv6_opt_hdr **)&opt2->srcrt,
1305 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1306 newopt, newtype, &p);
1307 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1308 (opt ? opt->dst1opt : NULL),
1309 newopt, newtype, &p);
1310
1311 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1312 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1313 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1314 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1315
1316 return opt2;
1317}
1318
1319struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1320 struct ipv6_txoptions *opt)
1321{
1322 /*
1323 * ignore the dest before srcrt unless srcrt is being included.
1324 * --yoshfuji
1325 */
1326 if (opt->dst0opt && !opt->srcrt) {
1327 if (opt_space != opt) {
1328 memcpy(opt_space, opt, sizeof(*opt_space));
1329 opt = opt_space;
1330 }
1331 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1332 opt->dst0opt = NULL;
1333 }
1334
1335 return opt;
1336}
1337EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
1338
1339/**
1340 * fl6_update_dst - update flowi destination address with info given
1341 * by srcrt option, if any.
1342 *
1343 * @fl6: flowi6 for which daddr is to be updated
1344 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1345 * @orig: copy of original daddr address if modified
1346 *
1347 * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1348 * and initial value of fl6->daddr set in orig
1349 */
1350struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1351 const struct ipv6_txoptions *opt,
1352 struct in6_addr *orig)
1353{
1354 if (!opt || !opt->srcrt)
1355 return NULL;
1356
1357 *orig = fl6->daddr;
1358
1359 switch (opt->srcrt->type) {
1360 case IPV6_SRCRT_TYPE_0:
1361 case IPV6_SRCRT_STRICT:
1362 case IPV6_SRCRT_TYPE_2:
1363 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1364 break;
1365 case IPV6_SRCRT_TYPE_4:
1366 {
1367 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1368
1369 fl6->daddr = srh->segments[srh->segments_left];
1370 break;
1371 }
1372 default:
1373 return NULL;
1374 }
1375
1376 return orig;
1377}
1378EXPORT_SYMBOL_GPL(fl6_update_dst);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Extension Header handling for IPv6
4 * Linux INET6 implementation
5 *
6 * Authors:
7 * Pedro Roque <roque@di.fc.ul.pt>
8 * Andi Kleen <ak@muc.de>
9 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
10 */
11
12/* Changes:
13 * yoshfuji : ensure not to overrun while parsing
14 * tlv options.
15 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
16 * YOSHIFUJI Hideaki @USAGI Register inbound extension header
17 * handlers as inet6_protocol{}.
18 */
19
20#include <linux/errno.h>
21#include <linux/types.h>
22#include <linux/socket.h>
23#include <linux/sockios.h>
24#include <linux/net.h>
25#include <linux/netdevice.h>
26#include <linux/in6.h>
27#include <linux/icmpv6.h>
28#include <linux/slab.h>
29#include <linux/export.h>
30
31#include <net/dst.h>
32#include <net/sock.h>
33#include <net/snmp.h>
34
35#include <net/ipv6.h>
36#include <net/protocol.h>
37#include <net/transp_v6.h>
38#include <net/rawv6.h>
39#include <net/ndisc.h>
40#include <net/ip6_route.h>
41#include <net/addrconf.h>
42#include <net/calipso.h>
43#if IS_ENABLED(CONFIG_IPV6_MIP6)
44#include <net/xfrm.h>
45#endif
46#include <linux/seg6.h>
47#include <net/seg6.h>
48#ifdef CONFIG_IPV6_SEG6_HMAC
49#include <net/seg6_hmac.h>
50#endif
51#include <net/rpl.h>
52#include <linux/ioam6.h>
53#include <net/ioam6.h>
54#include <net/dst_metadata.h>
55
56#include <linux/uaccess.h>
57
58/*********************
59 Generic functions
60 *********************/
61
62/* An unknown option is detected, decide what to do */
63
64static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
65 bool disallow_unknowns)
66{
67 if (disallow_unknowns) {
68 /* If unknown TLVs are disallowed by configuration
69 * then always silently drop packet. Note this also
70 * means no ICMP parameter problem is sent which
71 * could be a good property to mitigate a reflection DOS
72 * attack.
73 */
74
75 goto drop;
76 }
77
78 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
79 case 0: /* ignore */
80 return true;
81
82 case 1: /* drop packet */
83 break;
84
85 case 3: /* Send ICMP if not a multicast address and drop packet */
86 /* Actually, it is redundant check. icmp_send
87 will recheck in any case.
88 */
89 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
90 break;
91 fallthrough;
92 case 2: /* send ICMP PARM PROB regardless and drop packet */
93 icmpv6_param_prob_reason(skb, ICMPV6_UNK_OPTION, optoff,
94 SKB_DROP_REASON_UNHANDLED_PROTO);
95 return false;
96 }
97
98drop:
99 kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO);
100 return false;
101}
102
103static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
104static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
105static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
106static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
107#if IS_ENABLED(CONFIG_IPV6_MIP6)
108static bool ipv6_dest_hao(struct sk_buff *skb, int optoff);
109#endif
110
111/* Parse tlv encoded option header (hop-by-hop or destination) */
112
113static bool ip6_parse_tlv(bool hopbyhop,
114 struct sk_buff *skb,
115 int max_count)
116{
117 int len = (skb_transport_header(skb)[1] + 1) << 3;
118 const unsigned char *nh = skb_network_header(skb);
119 int off = skb_network_header_len(skb);
120 bool disallow_unknowns = false;
121 int tlv_count = 0;
122 int padlen = 0;
123
124 if (unlikely(max_count < 0)) {
125 disallow_unknowns = true;
126 max_count = -max_count;
127 }
128
129 off += 2;
130 len -= 2;
131
132 while (len > 0) {
133 int optlen, i;
134
135 if (nh[off] == IPV6_TLV_PAD1) {
136 padlen++;
137 if (padlen > 7)
138 goto bad;
139 off++;
140 len--;
141 continue;
142 }
143 if (len < 2)
144 goto bad;
145 optlen = nh[off + 1] + 2;
146 if (optlen > len)
147 goto bad;
148
149 if (nh[off] == IPV6_TLV_PADN) {
150 /* RFC 2460 states that the purpose of PadN is
151 * to align the containing header to multiples
152 * of 8. 7 is therefore the highest valid value.
153 * See also RFC 4942, Section 2.1.9.5.
154 */
155 padlen += optlen;
156 if (padlen > 7)
157 goto bad;
158 /* RFC 4942 recommends receiving hosts to
159 * actively check PadN payload to contain
160 * only zeroes.
161 */
162 for (i = 2; i < optlen; i++) {
163 if (nh[off + i] != 0)
164 goto bad;
165 }
166 } else {
167 tlv_count++;
168 if (tlv_count > max_count)
169 goto bad;
170
171 if (hopbyhop) {
172 switch (nh[off]) {
173 case IPV6_TLV_ROUTERALERT:
174 if (!ipv6_hop_ra(skb, off))
175 return false;
176 break;
177 case IPV6_TLV_IOAM:
178 if (!ipv6_hop_ioam(skb, off))
179 return false;
180
181 nh = skb_network_header(skb);
182 break;
183 case IPV6_TLV_JUMBO:
184 if (!ipv6_hop_jumbo(skb, off))
185 return false;
186 break;
187 case IPV6_TLV_CALIPSO:
188 if (!ipv6_hop_calipso(skb, off))
189 return false;
190 break;
191 default:
192 if (!ip6_tlvopt_unknown(skb, off,
193 disallow_unknowns))
194 return false;
195 break;
196 }
197 } else {
198 switch (nh[off]) {
199#if IS_ENABLED(CONFIG_IPV6_MIP6)
200 case IPV6_TLV_HAO:
201 if (!ipv6_dest_hao(skb, off))
202 return false;
203 break;
204#endif
205 default:
206 if (!ip6_tlvopt_unknown(skb, off,
207 disallow_unknowns))
208 return false;
209 break;
210 }
211 }
212 padlen = 0;
213 }
214 off += optlen;
215 len -= optlen;
216 }
217
218 if (len == 0)
219 return true;
220bad:
221 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
222 return false;
223}
224
225/*****************************
226 Destination options header.
227 *****************************/
228
229#if IS_ENABLED(CONFIG_IPV6_MIP6)
230static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
231{
232 struct ipv6_destopt_hao *hao;
233 struct inet6_skb_parm *opt = IP6CB(skb);
234 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
235 SKB_DR(reason);
236 int ret;
237
238 if (opt->dsthao) {
239 net_dbg_ratelimited("hao duplicated\n");
240 goto discard;
241 }
242 opt->dsthao = opt->dst1;
243 opt->dst1 = 0;
244
245 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
246
247 if (hao->length != 16) {
248 net_dbg_ratelimited("hao invalid option length = %d\n",
249 hao->length);
250 SKB_DR_SET(reason, IP_INHDR);
251 goto discard;
252 }
253
254 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
255 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
256 &hao->addr);
257 SKB_DR_SET(reason, INVALID_PROTO);
258 goto discard;
259 }
260
261 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
262 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
263 if (unlikely(ret < 0)) {
264 SKB_DR_SET(reason, XFRM_POLICY);
265 goto discard;
266 }
267
268 if (skb_cloned(skb)) {
269 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
270 goto discard;
271
272 /* update all variable using below by copied skbuff */
273 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
274 optoff);
275 ipv6h = ipv6_hdr(skb);
276 }
277
278 if (skb->ip_summed == CHECKSUM_COMPLETE)
279 skb->ip_summed = CHECKSUM_NONE;
280
281 swap(ipv6h->saddr, hao->addr);
282
283 if (skb->tstamp == 0)
284 __net_timestamp(skb);
285
286 return true;
287
288 discard:
289 kfree_skb_reason(skb, reason);
290 return false;
291}
292#endif
293
294static int ipv6_destopt_rcv(struct sk_buff *skb)
295{
296 struct inet6_dev *idev = __in6_dev_get(skb->dev);
297 struct inet6_skb_parm *opt = IP6CB(skb);
298#if IS_ENABLED(CONFIG_IPV6_MIP6)
299 __u16 dstbuf;
300#endif
301 struct dst_entry *dst = skb_dst(skb);
302 struct net *net = dev_net(skb->dev);
303 int extlen;
304
305 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
306 !pskb_may_pull(skb, (skb_transport_offset(skb) +
307 ((skb_transport_header(skb)[1] + 1) << 3)))) {
308 __IP6_INC_STATS(dev_net(dst->dev), idev,
309 IPSTATS_MIB_INHDRERRORS);
310fail_and_free:
311 kfree_skb(skb);
312 return -1;
313 }
314
315 extlen = (skb_transport_header(skb)[1] + 1) << 3;
316 if (extlen > net->ipv6.sysctl.max_dst_opts_len)
317 goto fail_and_free;
318
319 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
320#if IS_ENABLED(CONFIG_IPV6_MIP6)
321 dstbuf = opt->dst1;
322#endif
323
324 if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) {
325 skb->transport_header += extlen;
326 opt = IP6CB(skb);
327#if IS_ENABLED(CONFIG_IPV6_MIP6)
328 opt->nhoff = dstbuf;
329#else
330 opt->nhoff = opt->dst1;
331#endif
332 return 1;
333 }
334
335 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
336 return -1;
337}
338
339static void seg6_update_csum(struct sk_buff *skb)
340{
341 struct ipv6_sr_hdr *hdr;
342 struct in6_addr *addr;
343 __be32 from, to;
344
345 /* srh is at transport offset and seg_left is already decremented
346 * but daddr is not yet updated with next segment
347 */
348
349 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
350 addr = hdr->segments + hdr->segments_left;
351
352 hdr->segments_left++;
353 from = *(__be32 *)hdr;
354
355 hdr->segments_left--;
356 to = *(__be32 *)hdr;
357
358 /* update skb csum with diff resulting from seg_left decrement */
359
360 update_csum_diff4(skb, from, to);
361
362 /* compute csum diff between current and next segment and update */
363
364 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
365 (__be32 *)addr);
366}
367
368static int ipv6_srh_rcv(struct sk_buff *skb)
369{
370 struct inet6_skb_parm *opt = IP6CB(skb);
371 struct net *net = dev_net(skb->dev);
372 struct ipv6_sr_hdr *hdr;
373 struct inet6_dev *idev;
374 struct in6_addr *addr;
375 int accept_seg6;
376
377 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
378
379 idev = __in6_dev_get(skb->dev);
380
381 accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
382 if (accept_seg6 > idev->cnf.seg6_enabled)
383 accept_seg6 = idev->cnf.seg6_enabled;
384
385 if (!accept_seg6) {
386 kfree_skb(skb);
387 return -1;
388 }
389
390#ifdef CONFIG_IPV6_SEG6_HMAC
391 if (!seg6_hmac_validate_skb(skb)) {
392 kfree_skb(skb);
393 return -1;
394 }
395#endif
396
397looped_back:
398 if (hdr->segments_left == 0) {
399 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
400 int offset = (hdr->hdrlen + 1) << 3;
401
402 skb_postpull_rcsum(skb, skb_network_header(skb),
403 skb_network_header_len(skb));
404 skb_pull(skb, offset);
405 skb_postpull_rcsum(skb, skb_transport_header(skb),
406 offset);
407
408 skb_reset_network_header(skb);
409 skb_reset_transport_header(skb);
410 skb->encapsulation = 0;
411 if (hdr->nexthdr == NEXTHDR_IPV4)
412 skb->protocol = htons(ETH_P_IP);
413 __skb_tunnel_rx(skb, skb->dev, net);
414
415 netif_rx(skb);
416 return -1;
417 }
418
419 opt->srcrt = skb_network_header_len(skb);
420 opt->lastopt = opt->srcrt;
421 skb->transport_header += (hdr->hdrlen + 1) << 3;
422 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
423
424 return 1;
425 }
426
427 if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
428 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
429 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
430 ((&hdr->segments_left) -
431 skb_network_header(skb)));
432 return -1;
433 }
434
435 if (skb_cloned(skb)) {
436 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
437 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
438 IPSTATS_MIB_OUTDISCARDS);
439 kfree_skb(skb);
440 return -1;
441 }
442
443 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
444 }
445
446 hdr->segments_left--;
447 addr = hdr->segments + hdr->segments_left;
448
449 skb_push(skb, sizeof(struct ipv6hdr));
450
451 if (skb->ip_summed == CHECKSUM_COMPLETE)
452 seg6_update_csum(skb);
453
454 ipv6_hdr(skb)->daddr = *addr;
455
456 ip6_route_input(skb);
457
458 if (skb_dst(skb)->error) {
459 dst_input(skb);
460 return -1;
461 }
462
463 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
464 if (ipv6_hdr(skb)->hop_limit <= 1) {
465 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
466 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
467 ICMPV6_EXC_HOPLIMIT, 0);
468 kfree_skb(skb);
469 return -1;
470 }
471 ipv6_hdr(skb)->hop_limit--;
472
473 skb_pull(skb, sizeof(struct ipv6hdr));
474 goto looped_back;
475 }
476
477 dst_input(skb);
478
479 return -1;
480}
481
482static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
483{
484 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
485 struct inet6_skb_parm *opt = IP6CB(skb);
486 struct net *net = dev_net(skb->dev);
487 struct inet6_dev *idev;
488 struct ipv6hdr *oldhdr;
489 unsigned char *buf;
490 int accept_rpl_seg;
491 int i, err;
492 u64 n = 0;
493 u32 r;
494
495 idev = __in6_dev_get(skb->dev);
496
497 accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
498 if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
499 accept_rpl_seg = idev->cnf.rpl_seg_enabled;
500
501 if (!accept_rpl_seg) {
502 kfree_skb(skb);
503 return -1;
504 }
505
506looped_back:
507 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
508
509 if (hdr->segments_left == 0) {
510 if (hdr->nexthdr == NEXTHDR_IPV6) {
511 int offset = (hdr->hdrlen + 1) << 3;
512
513 skb_postpull_rcsum(skb, skb_network_header(skb),
514 skb_network_header_len(skb));
515 skb_pull(skb, offset);
516 skb_postpull_rcsum(skb, skb_transport_header(skb),
517 offset);
518
519 skb_reset_network_header(skb);
520 skb_reset_transport_header(skb);
521 skb->encapsulation = 0;
522
523 __skb_tunnel_rx(skb, skb->dev, net);
524
525 netif_rx(skb);
526 return -1;
527 }
528
529 opt->srcrt = skb_network_header_len(skb);
530 opt->lastopt = opt->srcrt;
531 skb->transport_header += (hdr->hdrlen + 1) << 3;
532 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
533
534 return 1;
535 }
536
537 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
538 r = do_div(n, (16 - hdr->cmpri));
539 /* checks if calculation was without remainder and n fits into
540 * unsigned char which is segments_left field. Should not be
541 * higher than that.
542 */
543 if (r || (n + 1) > 255) {
544 kfree_skb(skb);
545 return -1;
546 }
547
548 if (hdr->segments_left > n + 1) {
549 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
550 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
551 ((&hdr->segments_left) -
552 skb_network_header(skb)));
553 return -1;
554 }
555
556 hdr->segments_left--;
557 i = n - hdr->segments_left;
558
559 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
560 if (unlikely(!buf)) {
561 kfree_skb(skb);
562 return -1;
563 }
564
565 ohdr = (struct ipv6_rpl_sr_hdr *)buf;
566 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
567 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
568
569 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
570 kfree_skb(skb);
571 kfree(buf);
572 return -1;
573 }
574
575 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
576 if (err) {
577 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
578 kfree_skb(skb);
579 kfree(buf);
580 return -1;
581 }
582
583 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
584
585 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
586
587 oldhdr = ipv6_hdr(skb);
588
589 skb_pull(skb, ((hdr->hdrlen + 1) << 3));
590 skb_postpull_rcsum(skb, oldhdr,
591 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
592 if (unlikely(!hdr->segments_left)) {
593 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
594 GFP_ATOMIC)) {
595 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
596 kfree_skb(skb);
597 kfree(buf);
598 return -1;
599 }
600
601 oldhdr = ipv6_hdr(skb);
602 }
603 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
604 skb_reset_network_header(skb);
605 skb_mac_header_rebuild(skb);
606 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
607
608 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
609 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
610
611 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
612 skb_postpush_rcsum(skb, ipv6_hdr(skb),
613 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
614
615 kfree(buf);
616
617 ip6_route_input(skb);
618
619 if (skb_dst(skb)->error) {
620 dst_input(skb);
621 return -1;
622 }
623
624 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
625 if (ipv6_hdr(skb)->hop_limit <= 1) {
626 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
627 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
628 ICMPV6_EXC_HOPLIMIT, 0);
629 kfree_skb(skb);
630 return -1;
631 }
632 ipv6_hdr(skb)->hop_limit--;
633
634 skb_pull(skb, sizeof(struct ipv6hdr));
635 goto looped_back;
636 }
637
638 dst_input(skb);
639
640 return -1;
641}
642
643/********************************
644 Routing header.
645 ********************************/
646
647/* called with rcu_read_lock() */
648static int ipv6_rthdr_rcv(struct sk_buff *skb)
649{
650 struct inet6_dev *idev = __in6_dev_get(skb->dev);
651 struct inet6_skb_parm *opt = IP6CB(skb);
652 struct in6_addr *addr = NULL;
653 int n, i;
654 struct ipv6_rt_hdr *hdr;
655 struct rt0_hdr *rthdr;
656 struct net *net = dev_net(skb->dev);
657 int accept_source_route = net->ipv6.devconf_all->accept_source_route;
658
659 if (idev && accept_source_route > idev->cnf.accept_source_route)
660 accept_source_route = idev->cnf.accept_source_route;
661
662 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
663 !pskb_may_pull(skb, (skb_transport_offset(skb) +
664 ((skb_transport_header(skb)[1] + 1) << 3)))) {
665 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
666 kfree_skb(skb);
667 return -1;
668 }
669
670 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
671
672 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
673 skb->pkt_type != PACKET_HOST) {
674 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
675 kfree_skb(skb);
676 return -1;
677 }
678
679 switch (hdr->type) {
680 case IPV6_SRCRT_TYPE_4:
681 /* segment routing */
682 return ipv6_srh_rcv(skb);
683 case IPV6_SRCRT_TYPE_3:
684 /* rpl segment routing */
685 return ipv6_rpl_srh_rcv(skb);
686 default:
687 break;
688 }
689
690looped_back:
691 if (hdr->segments_left == 0) {
692 switch (hdr->type) {
693#if IS_ENABLED(CONFIG_IPV6_MIP6)
694 case IPV6_SRCRT_TYPE_2:
695 /* Silently discard type 2 header unless it was
696 * processed by own
697 */
698 if (!addr) {
699 __IP6_INC_STATS(net, idev,
700 IPSTATS_MIB_INADDRERRORS);
701 kfree_skb(skb);
702 return -1;
703 }
704 break;
705#endif
706 default:
707 break;
708 }
709
710 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
711 skb->transport_header += (hdr->hdrlen + 1) << 3;
712 opt->dst0 = opt->dst1;
713 opt->dst1 = 0;
714 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
715 return 1;
716 }
717
718 switch (hdr->type) {
719#if IS_ENABLED(CONFIG_IPV6_MIP6)
720 case IPV6_SRCRT_TYPE_2:
721 if (accept_source_route < 0)
722 goto unknown_rh;
723 /* Silently discard invalid RTH type 2 */
724 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
725 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
726 kfree_skb(skb);
727 return -1;
728 }
729 break;
730#endif
731 default:
732 goto unknown_rh;
733 }
734
735 /*
736 * This is the routing header forwarding algorithm from
737 * RFC 2460, page 16.
738 */
739
740 n = hdr->hdrlen >> 1;
741
742 if (hdr->segments_left > n) {
743 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
744 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
745 ((&hdr->segments_left) -
746 skb_network_header(skb)));
747 return -1;
748 }
749
750 /* We are about to mangle packet header. Be careful!
751 Do not damage packets queued somewhere.
752 */
753 if (skb_cloned(skb)) {
754 /* the copy is a forwarded packet */
755 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
756 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
757 IPSTATS_MIB_OUTDISCARDS);
758 kfree_skb(skb);
759 return -1;
760 }
761 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
762 }
763
764 if (skb->ip_summed == CHECKSUM_COMPLETE)
765 skb->ip_summed = CHECKSUM_NONE;
766
767 i = n - --hdr->segments_left;
768
769 rthdr = (struct rt0_hdr *) hdr;
770 addr = rthdr->addr;
771 addr += i - 1;
772
773 switch (hdr->type) {
774#if IS_ENABLED(CONFIG_IPV6_MIP6)
775 case IPV6_SRCRT_TYPE_2:
776 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
777 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
778 IPPROTO_ROUTING) < 0) {
779 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
780 kfree_skb(skb);
781 return -1;
782 }
783 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
784 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
785 kfree_skb(skb);
786 return -1;
787 }
788 break;
789#endif
790 default:
791 break;
792 }
793
794 if (ipv6_addr_is_multicast(addr)) {
795 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
796 kfree_skb(skb);
797 return -1;
798 }
799
800 swap(*addr, ipv6_hdr(skb)->daddr);
801
802 ip6_route_input(skb);
803 if (skb_dst(skb)->error) {
804 skb_push(skb, skb->data - skb_network_header(skb));
805 dst_input(skb);
806 return -1;
807 }
808
809 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
810 if (ipv6_hdr(skb)->hop_limit <= 1) {
811 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
812 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
813 0);
814 kfree_skb(skb);
815 return -1;
816 }
817 ipv6_hdr(skb)->hop_limit--;
818 goto looped_back;
819 }
820
821 skb_push(skb, skb->data - skb_network_header(skb));
822 dst_input(skb);
823 return -1;
824
825unknown_rh:
826 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
827 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
828 (&hdr->type) - skb_network_header(skb));
829 return -1;
830}
831
832static const struct inet6_protocol rthdr_protocol = {
833 .handler = ipv6_rthdr_rcv,
834 .flags = INET6_PROTO_NOPOLICY,
835};
836
837static const struct inet6_protocol destopt_protocol = {
838 .handler = ipv6_destopt_rcv,
839 .flags = INET6_PROTO_NOPOLICY,
840};
841
842static const struct inet6_protocol nodata_protocol = {
843 .handler = dst_discard,
844 .flags = INET6_PROTO_NOPOLICY,
845};
846
847int __init ipv6_exthdrs_init(void)
848{
849 int ret;
850
851 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
852 if (ret)
853 goto out;
854
855 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
856 if (ret)
857 goto out_rthdr;
858
859 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
860 if (ret)
861 goto out_destopt;
862
863out:
864 return ret;
865out_destopt:
866 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
867out_rthdr:
868 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
869 goto out;
870};
871
872void ipv6_exthdrs_exit(void)
873{
874 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
875 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
876 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
877}
878
879/**********************************
880 Hop-by-hop options.
881 **********************************/
882
883/*
884 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
885 */
886static inline struct net *ipv6_skb_net(struct sk_buff *skb)
887{
888 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
889}
890
891/* Router Alert as of RFC 2711 */
892
893static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
894{
895 const unsigned char *nh = skb_network_header(skb);
896
897 if (nh[optoff + 1] == 2) {
898 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
899 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
900 return true;
901 }
902 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
903 nh[optoff + 1]);
904 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
905 return false;
906}
907
908/* IOAM */
909
910static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
911{
912 struct ioam6_trace_hdr *trace;
913 struct ioam6_namespace *ns;
914 struct ioam6_hdr *hdr;
915
916 /* Bad alignment (must be 4n-aligned) */
917 if (optoff & 3)
918 goto drop;
919
920 /* Ignore if IOAM is not enabled on ingress */
921 if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
922 goto ignore;
923
924 /* Truncated Option header */
925 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
926 if (hdr->opt_len < 2)
927 goto drop;
928
929 switch (hdr->type) {
930 case IOAM6_TYPE_PREALLOC:
931 /* Truncated Pre-allocated Trace header */
932 if (hdr->opt_len < 2 + sizeof(*trace))
933 goto drop;
934
935 /* Malformed Pre-allocated Trace header */
936 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
937 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
938 goto drop;
939
940 /* Ignore if the IOAM namespace is unknown */
941 ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id);
942 if (!ns)
943 goto ignore;
944
945 if (!skb_valid_dst(skb))
946 ip6_route_input(skb);
947
948 /* About to mangle packet header */
949 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
950 goto drop;
951
952 /* Trace pointer may have changed */
953 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb)
954 + optoff + sizeof(*hdr));
955
956 ioam6_fill_trace_data(skb, ns, trace, true);
957 break;
958 default:
959 break;
960 }
961
962ignore:
963 return true;
964
965drop:
966 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
967 return false;
968}
969
970/* Jumbo payload */
971
972static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
973{
974 const unsigned char *nh = skb_network_header(skb);
975 SKB_DR(reason);
976 u32 pkt_len;
977
978 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
979 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
980 nh[optoff+1]);
981 SKB_DR_SET(reason, IP_INHDR);
982 goto drop;
983 }
984
985 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
986 if (pkt_len <= IPV6_MAXPLEN) {
987 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
988 SKB_DROP_REASON_IP_INHDR);
989 return false;
990 }
991 if (ipv6_hdr(skb)->payload_len) {
992 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
993 SKB_DROP_REASON_IP_INHDR);
994 return false;
995 }
996
997 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
998 SKB_DR_SET(reason, PKT_TOO_SMALL);
999 goto drop;
1000 }
1001
1002 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1003 goto drop;
1004
1005 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1006 return true;
1007
1008drop:
1009 kfree_skb_reason(skb, reason);
1010 return false;
1011}
1012
1013/* CALIPSO RFC 5570 */
1014
1015static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1016{
1017 const unsigned char *nh = skb_network_header(skb);
1018
1019 if (nh[optoff + 1] < 8)
1020 goto drop;
1021
1022 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1023 goto drop;
1024
1025 if (!calipso_validate(skb, nh + optoff))
1026 goto drop;
1027
1028 return true;
1029
1030drop:
1031 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1032 return false;
1033}
1034
1035int ipv6_parse_hopopts(struct sk_buff *skb)
1036{
1037 struct inet6_skb_parm *opt = IP6CB(skb);
1038 struct net *net = dev_net(skb->dev);
1039 int extlen;
1040
1041 /*
1042 * skb_network_header(skb) is equal to skb->data, and
1043 * skb_network_header_len(skb) is always equal to
1044 * sizeof(struct ipv6hdr) by definition of
1045 * hop-by-hop options.
1046 */
1047 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1048 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1049 ((skb_transport_header(skb)[1] + 1) << 3)))) {
1050fail_and_free:
1051 kfree_skb(skb);
1052 return -1;
1053 }
1054
1055 extlen = (skb_transport_header(skb)[1] + 1) << 3;
1056 if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1057 goto fail_and_free;
1058
1059 opt->flags |= IP6SKB_HOPBYHOP;
1060 if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
1061 skb->transport_header += extlen;
1062 opt = IP6CB(skb);
1063 opt->nhoff = sizeof(struct ipv6hdr);
1064 return 1;
1065 }
1066 return -1;
1067}
1068
1069/*
1070 * Creating outbound headers.
1071 *
1072 * "build" functions work when skb is filled from head to tail (datagram)
1073 * "push" functions work when headers are added from tail to head (tcp)
1074 *
1075 * In both cases we assume, that caller reserved enough room
1076 * for headers.
1077 */
1078
1079static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1080 struct ipv6_rt_hdr *opt,
1081 struct in6_addr **addr_p, struct in6_addr *saddr)
1082{
1083 struct rt0_hdr *phdr, *ihdr;
1084 int hops;
1085
1086 ihdr = (struct rt0_hdr *) opt;
1087
1088 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1089 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1090
1091 hops = ihdr->rt_hdr.hdrlen >> 1;
1092
1093 if (hops > 1)
1094 memcpy(phdr->addr, ihdr->addr + 1,
1095 (hops - 1) * sizeof(struct in6_addr));
1096
1097 phdr->addr[hops - 1] = **addr_p;
1098 *addr_p = ihdr->addr;
1099
1100 phdr->rt_hdr.nexthdr = *proto;
1101 *proto = NEXTHDR_ROUTING;
1102}
1103
1104static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1105 struct ipv6_rt_hdr *opt,
1106 struct in6_addr **addr_p, struct in6_addr *saddr)
1107{
1108 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1109 int plen, hops;
1110
1111 sr_ihdr = (struct ipv6_sr_hdr *)opt;
1112 plen = (sr_ihdr->hdrlen + 1) << 3;
1113
1114 sr_phdr = skb_push(skb, plen);
1115 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1116
1117 hops = sr_ihdr->first_segment + 1;
1118 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1119 (hops - 1) * sizeof(struct in6_addr));
1120
1121 sr_phdr->segments[0] = **addr_p;
1122 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1123
1124 if (sr_ihdr->hdrlen > hops * 2) {
1125 int tlvs_offset, tlvs_length;
1126
1127 tlvs_offset = (1 + hops * 2) << 3;
1128 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1129 memcpy((char *)sr_phdr + tlvs_offset,
1130 (char *)sr_ihdr + tlvs_offset, tlvs_length);
1131 }
1132
1133#ifdef CONFIG_IPV6_SEG6_HMAC
1134 if (sr_has_hmac(sr_phdr)) {
1135 struct net *net = NULL;
1136
1137 if (skb->dev)
1138 net = dev_net(skb->dev);
1139 else if (skb->sk)
1140 net = sock_net(skb->sk);
1141
1142 WARN_ON(!net);
1143
1144 if (net)
1145 seg6_push_hmac(net, saddr, sr_phdr);
1146 }
1147#endif
1148
1149 sr_phdr->nexthdr = *proto;
1150 *proto = NEXTHDR_ROUTING;
1151}
1152
1153static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1154 struct ipv6_rt_hdr *opt,
1155 struct in6_addr **addr_p, struct in6_addr *saddr)
1156{
1157 switch (opt->type) {
1158 case IPV6_SRCRT_TYPE_0:
1159 case IPV6_SRCRT_STRICT:
1160 case IPV6_SRCRT_TYPE_2:
1161 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1162 break;
1163 case IPV6_SRCRT_TYPE_4:
1164 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1165 break;
1166 default:
1167 break;
1168 }
1169}
1170
1171static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1172{
1173 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1174
1175 memcpy(h, opt, ipv6_optlen(opt));
1176 h->nexthdr = *proto;
1177 *proto = type;
1178}
1179
1180void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1181 u8 *proto,
1182 struct in6_addr **daddr, struct in6_addr *saddr)
1183{
1184 if (opt->srcrt) {
1185 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1186 /*
1187 * IPV6_RTHDRDSTOPTS is ignored
1188 * unless IPV6_RTHDR is set (RFC3542).
1189 */
1190 if (opt->dst0opt)
1191 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1192 }
1193 if (opt->hopopt)
1194 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1195}
1196
1197void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1198{
1199 if (opt->dst1opt)
1200 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1201}
1202EXPORT_SYMBOL(ipv6_push_frag_opts);
1203
1204struct ipv6_txoptions *
1205ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1206{
1207 struct ipv6_txoptions *opt2;
1208
1209 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1210 if (opt2) {
1211 long dif = (char *)opt2 - (char *)opt;
1212 memcpy(opt2, opt, opt->tot_len);
1213 if (opt2->hopopt)
1214 *((char **)&opt2->hopopt) += dif;
1215 if (opt2->dst0opt)
1216 *((char **)&opt2->dst0opt) += dif;
1217 if (opt2->dst1opt)
1218 *((char **)&opt2->dst1opt) += dif;
1219 if (opt2->srcrt)
1220 *((char **)&opt2->srcrt) += dif;
1221 refcount_set(&opt2->refcnt, 1);
1222 }
1223 return opt2;
1224}
1225EXPORT_SYMBOL_GPL(ipv6_dup_options);
1226
1227static void ipv6_renew_option(int renewtype,
1228 struct ipv6_opt_hdr **dest,
1229 struct ipv6_opt_hdr *old,
1230 struct ipv6_opt_hdr *new,
1231 int newtype, char **p)
1232{
1233 struct ipv6_opt_hdr *src;
1234
1235 src = (renewtype == newtype ? new : old);
1236 if (!src)
1237 return;
1238
1239 memcpy(*p, src, ipv6_optlen(src));
1240 *dest = (struct ipv6_opt_hdr *)*p;
1241 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1242}
1243
1244/**
1245 * ipv6_renew_options - replace a specific ext hdr with a new one.
1246 *
1247 * @sk: sock from which to allocate memory
1248 * @opt: original options
1249 * @newtype: option type to replace in @opt
1250 * @newopt: new option of type @newtype to replace (user-mem)
1251 *
1252 * Returns a new set of options which is a copy of @opt with the
1253 * option type @newtype replaced with @newopt.
1254 *
1255 * @opt may be NULL, in which case a new set of options is returned
1256 * containing just @newopt.
1257 *
1258 * @newopt may be NULL, in which case the specified option type is
1259 * not copied into the new set of options.
1260 *
1261 * The new set of options is allocated from the socket option memory
1262 * buffer of @sk.
1263 */
1264struct ipv6_txoptions *
1265ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1266 int newtype, struct ipv6_opt_hdr *newopt)
1267{
1268 int tot_len = 0;
1269 char *p;
1270 struct ipv6_txoptions *opt2;
1271
1272 if (opt) {
1273 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1274 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1275 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1276 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1277 if (newtype != IPV6_RTHDR && opt->srcrt)
1278 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1279 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1280 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1281 }
1282
1283 if (newopt)
1284 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1285
1286 if (!tot_len)
1287 return NULL;
1288
1289 tot_len += sizeof(*opt2);
1290 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1291 if (!opt2)
1292 return ERR_PTR(-ENOBUFS);
1293
1294 memset(opt2, 0, tot_len);
1295 refcount_set(&opt2->refcnt, 1);
1296 opt2->tot_len = tot_len;
1297 p = (char *)(opt2 + 1);
1298
1299 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1300 (opt ? opt->hopopt : NULL),
1301 newopt, newtype, &p);
1302 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1303 (opt ? opt->dst0opt : NULL),
1304 newopt, newtype, &p);
1305 ipv6_renew_option(IPV6_RTHDR,
1306 (struct ipv6_opt_hdr **)&opt2->srcrt,
1307 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1308 newopt, newtype, &p);
1309 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1310 (opt ? opt->dst1opt : NULL),
1311 newopt, newtype, &p);
1312
1313 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1314 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1315 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1316 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1317
1318 return opt2;
1319}
1320
1321struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1322 struct ipv6_txoptions *opt)
1323{
1324 /*
1325 * ignore the dest before srcrt unless srcrt is being included.
1326 * --yoshfuji
1327 */
1328 if (opt->dst0opt && !opt->srcrt) {
1329 if (opt_space != opt) {
1330 memcpy(opt_space, opt, sizeof(*opt_space));
1331 opt = opt_space;
1332 }
1333 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1334 opt->dst0opt = NULL;
1335 }
1336
1337 return opt;
1338}
1339EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
1340
1341/**
1342 * fl6_update_dst - update flowi destination address with info given
1343 * by srcrt option, if any.
1344 *
1345 * @fl6: flowi6 for which daddr is to be updated
1346 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1347 * @orig: copy of original daddr address if modified
1348 *
1349 * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1350 * and initial value of fl6->daddr set in orig
1351 */
1352struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1353 const struct ipv6_txoptions *opt,
1354 struct in6_addr *orig)
1355{
1356 if (!opt || !opt->srcrt)
1357 return NULL;
1358
1359 *orig = fl6->daddr;
1360
1361 switch (opt->srcrt->type) {
1362 case IPV6_SRCRT_TYPE_0:
1363 case IPV6_SRCRT_STRICT:
1364 case IPV6_SRCRT_TYPE_2:
1365 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1366 break;
1367 case IPV6_SRCRT_TYPE_4:
1368 {
1369 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1370
1371 fl6->daddr = srh->segments[srh->segments_left];
1372 break;
1373 }
1374 default:
1375 return NULL;
1376 }
1377
1378 return orig;
1379}
1380EXPORT_SYMBOL_GPL(fl6_update_dst);