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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 <[email protected]>
8 * Andi Kleen <[email protected]>
9 * Alexey Kuznetsov <[email protected]>
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 break;
182 case IPV6_TLV_JUMBO:
183 if (!ipv6_hop_jumbo(skb, off))
184 return false;
185 break;
186 case IPV6_TLV_CALIPSO:
187 if (!ipv6_hop_calipso(skb, off))
188 return false;
189 break;
190 default:
191 if (!ip6_tlvopt_unknown(skb, off,
192 disallow_unknowns))
193 return false;
194 break;
195 }
196 } else {
197 switch (nh[off]) {
198#if IS_ENABLED(CONFIG_IPV6_MIP6)
199 case IPV6_TLV_HAO:
200 if (!ipv6_dest_hao(skb, off))
201 return false;
202 break;
203#endif
204 default:
205 if (!ip6_tlvopt_unknown(skb, off,
206 disallow_unknowns))
207 return false;
208 break;
209 }
210 }
211 padlen = 0;
212
213 /* recompute the network header pointer in case it has changed */
214 nh = skb_network_header(skb);
215 }
216 off += optlen;
217 len -= optlen;
218 }
219
220 if (len == 0)
221 return true;
222bad:
223 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
224 return false;
225}
226
227/*****************************
228 Destination options header.
229 *****************************/
230
231#if IS_ENABLED(CONFIG_IPV6_MIP6)
232static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
233{
234 struct ipv6_destopt_hao *hao;
235 struct inet6_skb_parm *opt = IP6CB(skb);
236 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
237 SKB_DR(reason);
238 int ret;
239
240 if (opt->dsthao) {
241 net_dbg_ratelimited("hao duplicated\n");
242 goto discard;
243 }
244 opt->dsthao = opt->dst1;
245 opt->dst1 = 0;
246
247 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
248
249 if (hao->length != 16) {
250 net_dbg_ratelimited("hao invalid option length = %d\n",
251 hao->length);
252 SKB_DR_SET(reason, IP_INHDR);
253 goto discard;
254 }
255
256 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
257 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
258 &hao->addr);
259 SKB_DR_SET(reason, INVALID_PROTO);
260 goto discard;
261 }
262
263 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
264 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
265 if (unlikely(ret < 0)) {
266 SKB_DR_SET(reason, XFRM_POLICY);
267 goto discard;
268 }
269
270 if (skb_cloned(skb)) {
271 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
272 goto discard;
273
274 /* update all variable using below by copied skbuff */
275 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
276 optoff);
277 ipv6h = ipv6_hdr(skb);
278 }
279
280 if (skb->ip_summed == CHECKSUM_COMPLETE)
281 skb->ip_summed = CHECKSUM_NONE;
282
283 swap(ipv6h->saddr, hao->addr);
284
285 if (skb->tstamp == 0)
286 __net_timestamp(skb);
287
288 return true;
289
290 discard:
291 kfree_skb_reason(skb, reason);
292 return false;
293}
294#endif
295
296static int ipv6_destopt_rcv(struct sk_buff *skb)
297{
298 struct inet6_dev *idev = __in6_dev_get(skb->dev);
299 struct inet6_skb_parm *opt = IP6CB(skb);
300#if IS_ENABLED(CONFIG_IPV6_MIP6)
301 __u16 dstbuf;
302#endif
303 struct dst_entry *dst = skb_dst(skb);
304 struct net *net = dev_net(skb->dev);
305 int extlen;
306
307 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
308 !pskb_may_pull(skb, (skb_transport_offset(skb) +
309 ((skb_transport_header(skb)[1] + 1) << 3)))) {
310 __IP6_INC_STATS(dev_net(dst_dev(dst)), idev,
311 IPSTATS_MIB_INHDRERRORS);
312fail_and_free:
313 kfree_skb(skb);
314 return -1;
315 }
316
317 extlen = (skb_transport_header(skb)[1] + 1) << 3;
318 if (extlen > READ_ONCE(net->ipv6.sysctl.max_dst_opts_len))
319 goto fail_and_free;
320
321 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
322#if IS_ENABLED(CONFIG_IPV6_MIP6)
323 dstbuf = opt->dst1;
324#endif
325
326 if (ip6_parse_tlv(false, skb,
327 READ_ONCE(net->ipv6.sysctl.max_dst_opts_cnt))) {
328 skb->transport_header += extlen;
329 opt = IP6CB(skb);
330#if IS_ENABLED(CONFIG_IPV6_MIP6)
331 opt->nhoff = dstbuf;
332#else
333 opt->nhoff = opt->dst1;
334#endif
335 return 1;
336 }
337
338 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
339 return -1;
340}
341
342static void seg6_update_csum(struct sk_buff *skb)
343{
344 struct ipv6_sr_hdr *hdr;
345 struct in6_addr *addr;
346 __be32 from, to;
347
348 /* srh is at transport offset and seg_left is already decremented
349 * but daddr is not yet updated with next segment
350 */
351
352 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
353 addr = hdr->segments + hdr->segments_left;
354
355 hdr->segments_left++;
356 from = *(__be32 *)hdr;
357
358 hdr->segments_left--;
359 to = *(__be32 *)hdr;
360
361 /* update skb csum with diff resulting from seg_left decrement */
362
363 update_csum_diff4(skb, from, to);
364
365 /* compute csum diff between current and next segment and update */
366
367 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
368 (__be32 *)addr);
369}
370
371static int ipv6_srh_rcv(struct sk_buff *skb, struct inet6_dev *idev)
372{
373 struct inet6_skb_parm *opt = IP6CB(skb);
374 struct net *net = dev_net(skb->dev);
375 struct ipv6_sr_hdr *hdr;
376 struct in6_addr *addr;
377 int accept_seg6;
378
379 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
380
381 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled),
382 READ_ONCE(idev->cnf.seg6_enabled));
383
384 if (!accept_seg6) {
385 kfree_skb(skb);
386 return -1;
387 }
388
389#ifdef CONFIG_IPV6_SEG6_HMAC
390 if (!seg6_hmac_validate_skb(skb)) {
391 kfree_skb(skb);
392 return -1;
393 }
394#endif
395
396looped_back:
397 if (hdr->segments_left == 0) {
398 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
399 int offset = (hdr->hdrlen + 1) << 3;
400
401 skb_postpull_rcsum(skb, skb_network_header(skb),
402 skb_network_header_len(skb));
403 skb_pull(skb, offset);
404 skb_postpull_rcsum(skb, skb_transport_header(skb),
405 offset);
406
407 skb_reset_network_header(skb);
408 skb_reset_transport_header(skb);
409 skb->encapsulation = 0;
410 if (hdr->nexthdr == NEXTHDR_IPV4)
411 skb->protocol = htons(ETH_P_IP);
412 __skb_tunnel_rx(skb, skb->dev, net);
413
414 netif_rx(skb);
415 return -1;
416 }
417
418 opt->srcrt = skb_network_header_len(skb);
419 opt->lastopt = opt->srcrt;
420 skb->transport_header += (hdr->hdrlen + 1) << 3;
421 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
422
423 return 1;
424 }
425
426 if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
427 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
428 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
429 ((&hdr->segments_left) -
430 skb_network_header(skb)));
431 return -1;
432 }
433
434 if (skb_cloned(skb)) {
435 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
436 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
437 IPSTATS_MIB_OUTDISCARDS);
438 kfree_skb(skb);
439 return -1;
440 }
441
442 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
443 }
444
445 hdr->segments_left--;
446 addr = hdr->segments + hdr->segments_left;
447
448 skb_push(skb, -skb_network_offset(skb));
449
450 if (skb->ip_summed == CHECKSUM_COMPLETE)
451 seg6_update_csum(skb);
452
453 ipv6_hdr(skb)->daddr = *addr;
454
455 ip6_route_input(skb);
456
457 if (skb_dst(skb)->error) {
458 dst_input(skb);
459 return -1;
460 }
461
462 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
463 if (ipv6_hdr(skb)->hop_limit <= 1) {
464 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
465 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
466 ICMPV6_EXC_HOPLIMIT, 0);
467 kfree_skb(skb);
468 return -1;
469 }
470 ipv6_hdr(skb)->hop_limit--;
471
472 skb_pull(skb, skb_transport_offset(skb));
473 goto looped_back;
474 }
475
476 dst_input(skb);
477
478 return -1;
479}
480
481static int ipv6_rpl_srh_rcv(struct sk_buff *skb, struct inet6_dev *idev)
482{
483 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
484 struct inet6_skb_parm *opt = IP6CB(skb);
485 struct net *net = dev_net(skb->dev);
486 struct ipv6hdr *oldhdr;
487 unsigned int chdr_len;
488 unsigned char *buf;
489 int accept_rpl_seg;
490 int i, err;
491 u64 n = 0;
492 u32 r;
493
494 accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled),
495 READ_ONCE(idev->cnf.rpl_seg_enabled));
496 if (!accept_rpl_seg) {
497 kfree_skb(skb);
498 return -1;
499 }
500
501looped_back:
502 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
503
504 if (hdr->segments_left == 0) {
505 if (hdr->nexthdr == NEXTHDR_IPV6) {
506 int offset = (hdr->hdrlen + 1) << 3;
507
508 skb_postpull_rcsum(skb, skb_network_header(skb),
509 skb_network_header_len(skb));
510 skb_pull(skb, offset);
511 skb_postpull_rcsum(skb, skb_transport_header(skb),
512 offset);
513
514 skb_reset_network_header(skb);
515 skb_reset_transport_header(skb);
516 skb->encapsulation = 0;
517
518 __skb_tunnel_rx(skb, skb->dev, net);
519
520 netif_rx(skb);
521 return -1;
522 }
523
524 opt->srcrt = skb_network_header_len(skb);
525 opt->lastopt = opt->srcrt;
526 skb->transport_header += (hdr->hdrlen + 1) << 3;
527 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
528
529 return 1;
530 }
531
532 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
533 r = do_div(n, (16 - hdr->cmpri));
534 /* checks if calculation was without remainder and n fits into
535 * unsigned char which is segments_left field. Should not be
536 * higher than that.
537 */
538 if (r || (n + 1) > 127) {
539 kfree_skb(skb);
540 return -1;
541 }
542
543 if (hdr->segments_left > n + 1) {
544 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
545 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
546 ((&hdr->segments_left) -
547 skb_network_header(skb)));
548 return -1;
549 }
550
551 hdr->segments_left--;
552 i = n - hdr->segments_left;
553
554 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
555 if (unlikely(!buf)) {
556 kfree_skb(skb);
557 return -1;
558 }
559
560 ohdr = (struct ipv6_rpl_sr_hdr *)buf;
561 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
562 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
563
564 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
565 kfree_skb(skb);
566 kfree(buf);
567 return -1;
568 }
569
570 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
571 if (err) {
572 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
573 kfree_skb(skb);
574 kfree(buf);
575 return -1;
576 }
577
578 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
579
580 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
581
582 oldhdr = ipv6_hdr(skb);
583
584 skb_pull(skb, ((hdr->hdrlen + 1) << 3));
585 skb_postpull_rcsum(skb, oldhdr,
586 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
587 chdr_len = sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3);
588 if (unlikely(!hdr->segments_left ||
589 skb_headroom(skb) < chdr_len + skb->mac_len)) {
590 if (pskb_expand_head(skb, chdr_len + skb->mac_len, 0,
591 GFP_ATOMIC)) {
592 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
593 kfree_skb(skb);
594 kfree(buf);
595 return -1;
596 }
597
598 oldhdr = ipv6_hdr(skb);
599 }
600 skb_push(skb, chdr_len);
601 skb_reset_network_header(skb);
602 skb_mac_header_rebuild(skb);
603 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
604
605 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
606 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
607
608 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
609 skb_postpush_rcsum(skb, ipv6_hdr(skb),
610 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
611
612 kfree(buf);
613
614 ip6_route_input(skb);
615
616 if (skb_dst(skb)->error) {
617 dst_input(skb);
618 return -1;
619 }
620
621 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
622 if (ipv6_hdr(skb)->hop_limit <= 1) {
623 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
624 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
625 ICMPV6_EXC_HOPLIMIT, 0);
626 kfree_skb(skb);
627 return -1;
628 }
629 ipv6_hdr(skb)->hop_limit--;
630
631 skb_pull(skb, sizeof(struct ipv6hdr));
632 goto looped_back;
633 }
634
635 dst_input(skb);
636
637 return -1;
638}
639
640/********************************
641 Routing header.
642 ********************************/
643
644/* called with rcu_read_lock() */
645static int ipv6_rthdr_rcv(struct sk_buff *skb)
646{
647 struct inet6_dev *idev = __in6_dev_get(skb->dev);
648 struct inet6_skb_parm *opt = IP6CB(skb);
649 struct in6_addr *addr = NULL;
650 int n, i;
651 struct ipv6_rt_hdr *hdr;
652 struct rt0_hdr *rthdr;
653 struct net *net = dev_net(skb->dev);
654 int accept_source_route;
655
656 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
657
658 if (idev)
659 accept_source_route = min(accept_source_route,
660 READ_ONCE(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 if (!idev)
683 goto disabled;
684 return ipv6_srh_rcv(skb, idev);
685 case IPV6_SRCRT_TYPE_3:
686 /* rpl segment routing */
687 if (!idev)
688 goto disabled;
689 return ipv6_rpl_srh_rcv(skb, idev);
690 default:
691 break;
692 }
693
694looped_back:
695 if (hdr->segments_left == 0) {
696 switch (hdr->type) {
697#if IS_ENABLED(CONFIG_IPV6_MIP6)
698 case IPV6_SRCRT_TYPE_2:
699 /* Silently discard type 2 header unless it was
700 * processed by own
701 */
702 if (!addr) {
703 __IP6_INC_STATS(net, idev,
704 IPSTATS_MIB_INADDRERRORS);
705 kfree_skb(skb);
706 return -1;
707 }
708 break;
709#endif
710 default:
711 break;
712 }
713
714 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
715 skb->transport_header += (hdr->hdrlen + 1) << 3;
716 opt->dst0 = opt->dst1;
717 opt->dst1 = 0;
718 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
719 return 1;
720 }
721
722 switch (hdr->type) {
723#if IS_ENABLED(CONFIG_IPV6_MIP6)
724 case IPV6_SRCRT_TYPE_2:
725 if (accept_source_route < 0)
726 goto unknown_rh;
727 /* Silently discard invalid RTH type 2 */
728 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
729 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
730 kfree_skb(skb);
731 return -1;
732 }
733 break;
734#endif
735 default:
736 goto unknown_rh;
737 }
738
739 /*
740 * This is the routing header forwarding algorithm from
741 * RFC 2460, page 16.
742 */
743
744 n = hdr->hdrlen >> 1;
745
746 if (hdr->segments_left > n) {
747 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
748 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
749 ((&hdr->segments_left) -
750 skb_network_header(skb)));
751 return -1;
752 }
753
754 /* We are about to mangle packet header. Be careful!
755 Do not damage packets queued somewhere.
756 */
757 if (skb_cloned(skb)) {
758 /* the copy is a forwarded packet */
759 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
760 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
761 IPSTATS_MIB_OUTDISCARDS);
762 kfree_skb(skb);
763 return -1;
764 }
765 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
766 }
767
768 if (skb->ip_summed == CHECKSUM_COMPLETE)
769 skb->ip_summed = CHECKSUM_NONE;
770
771 i = n - --hdr->segments_left;
772
773 rthdr = (struct rt0_hdr *) hdr;
774 addr = rthdr->addr;
775 addr += i - 1;
776
777 switch (hdr->type) {
778#if IS_ENABLED(CONFIG_IPV6_MIP6)
779 case IPV6_SRCRT_TYPE_2:
780 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
781 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
782 IPPROTO_ROUTING) < 0) {
783 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
784 kfree_skb(skb);
785 return -1;
786 }
787 if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) {
788 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
789 kfree_skb(skb);
790 return -1;
791 }
792 break;
793#endif
794 default:
795 break;
796 }
797
798 if (ipv6_addr_is_multicast(addr)) {
799 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
800 kfree_skb(skb);
801 return -1;
802 }
803
804 swap(*addr, ipv6_hdr(skb)->daddr);
805
806 ip6_route_input(skb);
807 if (skb_dst(skb)->error) {
808 skb_push(skb, -skb_network_offset(skb));
809 dst_input(skb);
810 return -1;
811 }
812
813 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
814 if (ipv6_hdr(skb)->hop_limit <= 1) {
815 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
816 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
817 0);
818 kfree_skb(skb);
819 return -1;
820 }
821 ipv6_hdr(skb)->hop_limit--;
822 goto looped_back;
823 }
824
825 skb_push(skb, -skb_network_offset(skb));
826 dst_input(skb);
827 return -1;
828
829unknown_rh:
830 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
831 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
832 (&hdr->type) - skb_network_header(skb));
833 return -1;
834
835disabled:
836 kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
837 return -1;
838}
839
840static const struct inet6_protocol rthdr_protocol = {
841 .handler = ipv6_rthdr_rcv,
842 .flags = INET6_PROTO_NOPOLICY,
843};
844
845static const struct inet6_protocol destopt_protocol = {
846 .handler = ipv6_destopt_rcv,
847 .flags = INET6_PROTO_NOPOLICY,
848};
849
850static const struct inet6_protocol nodata_protocol = {
851 .handler = dst_discard,
852 .flags = INET6_PROTO_NOPOLICY,
853};
854
855int __init ipv6_exthdrs_init(void)
856{
857 int ret;
858
859 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
860 if (ret)
861 goto out;
862
863 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
864 if (ret)
865 goto out_rthdr;
866
867 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
868 if (ret)
869 goto out_destopt;
870
871out:
872 return ret;
873out_destopt:
874 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
875out_rthdr:
876 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
877 goto out;
878};
879
880void ipv6_exthdrs_exit(void)
881{
882 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
883 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
884 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
885}
886
887/**********************************
888 Hop-by-hop options.
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 enum skb_drop_reason drop_reason;
913 struct ioam6_trace_hdr *trace;
914 struct ioam6_namespace *ns;
915 struct inet6_dev *idev;
916 struct ioam6_hdr *hdr;
917
918 drop_reason = SKB_DROP_REASON_IP_INHDR;
919
920 /* Bad alignment (must be 4n-aligned) */
921 if (optoff & 3)
922 goto drop;
923
924 /* Does the device still have IPv6 configuration? */
925 idev = __in6_dev_get(skb->dev);
926 if (!idev) {
927 drop_reason = SKB_DROP_REASON_IPV6DISABLED;
928 goto drop;
929 }
930
931 /* Ignore if IOAM is not enabled on ingress */
932 if (!READ_ONCE(idev->cnf.ioam6_enabled))
933 goto ignore;
934
935 /* Truncated Option header */
936 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
937 if (hdr->opt_len < 2)
938 goto drop;
939
940 switch (hdr->type) {
941 case IOAM6_TYPE_PREALLOC:
942 /* Truncated Pre-allocated Trace header */
943 if (hdr->opt_len < 2 + sizeof(*trace))
944 goto drop;
945
946 /* Malformed Pre-allocated Trace header */
947 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
948 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
949 goto drop;
950
951 /* Inconsistent Pre-allocated Trace header */
952 if (trace->nodelen !=
953 ioam6_trace_compute_nodelen(be32_to_cpu(trace->type_be32)))
954 goto drop;
955
956 /* Ignore if the IOAM namespace is unknown */
957 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id);
958 if (!ns)
959 goto ignore;
960
961 if (!skb_valid_dst(skb))
962 ip6_route_input(skb);
963
964 /* About to mangle packet header */
965 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
966 goto drop;
967
968 /* Trace and hdr pointers may have changed */
969 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
970 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
971
972 ioam6_fill_trace_data(skb, ns, trace, true);
973
974 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev),
975 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2);
976 break;
977 default:
978 break;
979 }
980
981ignore:
982 return true;
983
984drop:
985 kfree_skb_reason(skb, drop_reason);
986 return false;
987}
988
989/* Jumbo payload */
990
991static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
992{
993 const unsigned char *nh = skb_network_header(skb);
994 SKB_DR(reason);
995 u32 pkt_len;
996
997 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
998 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
999 nh[optoff+1]);
1000 SKB_DR_SET(reason, IP_INHDR);
1001 goto drop;
1002 }
1003
1004 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
1005 if (pkt_len <= IPV6_MAXPLEN) {
1006 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
1007 SKB_DROP_REASON_IP_INHDR);
1008 return false;
1009 }
1010 if (ipv6_hdr(skb)->payload_len) {
1011 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
1012 SKB_DROP_REASON_IP_INHDR);
1013 return false;
1014 }
1015
1016 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
1017 SKB_DR_SET(reason, PKT_TOO_SMALL);
1018 goto drop;
1019 }
1020
1021 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1022 goto drop;
1023
1024 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1025 return true;
1026
1027drop:
1028 kfree_skb_reason(skb, reason);
1029 return false;
1030}
1031
1032/* CALIPSO RFC 5570 */
1033
1034static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1035{
1036 const unsigned char *nh = skb_network_header(skb);
1037
1038 if (nh[optoff + 1] < 8)
1039 goto drop;
1040
1041 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1042 goto drop;
1043
1044 if (!calipso_validate(skb, nh + optoff))
1045 goto drop;
1046
1047 return true;
1048
1049drop:
1050 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1051 return false;
1052}
1053
1054int ipv6_parse_hopopts(struct sk_buff *skb)
1055{
1056 struct inet6_skb_parm *opt = IP6CB(skb);
1057 struct net *net = dev_net(skb->dev);
1058 int extlen;
1059
1060 /*
1061 * skb_network_header(skb) is equal to skb->data, and
1062 * skb_network_header_len(skb) is always equal to
1063 * sizeof(struct ipv6hdr) by definition of
1064 * hop-by-hop options.
1065 */
1066 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1067 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1068 ((skb_transport_header(skb)[1] + 1) << 3)))) {
1069fail_and_free:
1070 kfree_skb(skb);
1071 return -1;
1072 }
1073
1074 extlen = (skb_transport_header(skb)[1] + 1) << 3;
1075 if (extlen > READ_ONCE(net->ipv6.sysctl.max_hbh_opts_len))
1076 goto fail_and_free;
1077
1078 opt->flags |= IP6SKB_HOPBYHOP;
1079 if (ip6_parse_tlv(true, skb,
1080 READ_ONCE(net->ipv6.sysctl.max_hbh_opts_cnt))) {
1081 skb->transport_header += extlen;
1082 opt = IP6CB(skb);
1083 opt->nhoff = sizeof(struct ipv6hdr);
1084 return 1;
1085 }
1086 return -1;
1087}
1088
1089/*
1090 * Creating outbound headers.
1091 *
1092 * "build" functions work when skb is filled from head to tail (datagram)
1093 * "push" functions work when headers are added from tail to head (tcp)
1094 *
1095 * In both cases we assume, that caller reserved enough room
1096 * for headers.
1097 */
1098
1099static u8 ipv6_push_rthdr0(struct sk_buff *skb, u8 proto,
1100 struct ipv6_rt_hdr *opt,
1101 struct in6_addr **addr_p, struct in6_addr *saddr)
1102{
1103 struct rt0_hdr *phdr, *ihdr;
1104 int hops;
1105
1106 ihdr = (struct rt0_hdr *) opt;
1107
1108 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1109 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1110
1111 hops = ihdr->rt_hdr.hdrlen >> 1;
1112
1113 if (hops > 1)
1114 memcpy(phdr->addr, ihdr->addr + 1,
1115 (hops - 1) * sizeof(struct in6_addr));
1116
1117 phdr->addr[hops - 1] = **addr_p;
1118 *addr_p = ihdr->addr;
1119
1120 phdr->rt_hdr.nexthdr = proto;
1121 return NEXTHDR_ROUTING;
1122}
1123
1124static u8 ipv6_push_rthdr4(struct sk_buff *skb, u8 proto,
1125 struct ipv6_rt_hdr *opt,
1126 struct in6_addr **addr_p, struct in6_addr *saddr)
1127{
1128 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1129 int plen, hops;
1130
1131 sr_ihdr = (struct ipv6_sr_hdr *)opt;
1132 plen = (sr_ihdr->hdrlen + 1) << 3;
1133
1134 sr_phdr = skb_push(skb, plen);
1135 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1136
1137 hops = sr_ihdr->first_segment + 1;
1138 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1139 (hops - 1) * sizeof(struct in6_addr));
1140
1141 sr_phdr->segments[0] = **addr_p;
1142 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1143
1144 if (sr_ihdr->hdrlen > hops * 2) {
1145 int tlvs_offset, tlvs_length;
1146
1147 tlvs_offset = (1 + hops * 2) << 3;
1148 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1149 memcpy((char *)sr_phdr + tlvs_offset,
1150 (char *)sr_ihdr + tlvs_offset, tlvs_length);
1151 }
1152
1153#ifdef CONFIG_IPV6_SEG6_HMAC
1154 if (sr_has_hmac(sr_phdr)) {
1155 struct net *net = NULL;
1156
1157 if (skb->dev)
1158 net = dev_net(skb->dev);
1159 else if (skb->sk)
1160 net = sock_net(skb->sk);
1161
1162 WARN_ON(!net);
1163
1164 if (net)
1165 seg6_push_hmac(net, saddr, sr_phdr);
1166 }
1167#endif
1168
1169 sr_phdr->nexthdr = proto;
1170 return NEXTHDR_ROUTING;
1171}
1172
1173static u8 ipv6_push_rthdr(struct sk_buff *skb, u8 proto,
1174 struct ipv6_rt_hdr *opt,
1175 struct in6_addr **addr_p, struct in6_addr *saddr)
1176{
1177 switch (opt->type) {
1178 case IPV6_SRCRT_TYPE_0:
1179 case IPV6_SRCRT_STRICT:
1180 case IPV6_SRCRT_TYPE_2:
1181 proto = ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1182 break;
1183 case IPV6_SRCRT_TYPE_4:
1184 proto = ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1185 break;
1186 default:
1187 break;
1188 }
1189 return proto;
1190}
1191
1192static u8 ipv6_push_exthdr(struct sk_buff *skb, u8 proto, u8 type, struct ipv6_opt_hdr *opt)
1193{
1194 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1195
1196 memcpy(h, opt, ipv6_optlen(opt));
1197 h->nexthdr = proto;
1198 return type;
1199}
1200
1201u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1202 u8 proto,
1203 struct in6_addr **daddr, struct in6_addr *saddr)
1204{
1205 if (opt->srcrt) {
1206 proto = ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1207 /*
1208 * IPV6_RTHDRDSTOPTS is ignored
1209 * unless IPV6_RTHDR is set (RFC3542).
1210 */
1211 if (opt->dst0opt)
1212 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1213 }
1214 if (opt->hopopt)
1215 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1216 return proto;
1217}
1218
1219u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 proto)
1220{
1221 if (opt->dst1opt)
1222 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1223 return proto;
1224}
1225EXPORT_SYMBOL(ipv6_push_frag_opts);
1226
1227struct ipv6_txoptions *
1228ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1229{
1230 struct ipv6_txoptions *opt2;
1231
1232 opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC);
1233 if (opt2) {
1234 long dif = (char *)opt2 - (char *)opt;
1235 if (opt2->hopopt)
1236 *((char **)&opt2->hopopt) += dif;
1237 if (opt2->dst0opt)
1238 *((char **)&opt2->dst0opt) += dif;
1239 if (opt2->dst1opt)
1240 *((char **)&opt2->dst1opt) += dif;
1241 if (opt2->srcrt)
1242 *((char **)&opt2->srcrt) += dif;
1243 refcount_set(&opt2->refcnt, 1);
1244 }
1245 return opt2;
1246}
1247EXPORT_SYMBOL_GPL(ipv6_dup_options);
1248
1249static void ipv6_renew_option(int renewtype,
1250 struct ipv6_opt_hdr **dest,
1251 struct ipv6_opt_hdr *old,
1252 struct ipv6_opt_hdr *new,
1253 int newtype, char **p)
1254{
1255 struct ipv6_opt_hdr *src;
1256
1257 src = (renewtype == newtype ? new : old);
1258 if (!src)
1259 return;
1260
1261 memcpy(*p, src, ipv6_optlen(src));
1262 *dest = (struct ipv6_opt_hdr *)*p;
1263 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1264}
1265
1266/**
1267 * ipv6_renew_options - replace a specific ext hdr with a new one.
1268 *
1269 * @sk: sock from which to allocate memory
1270 * @opt: original options
1271 * @newtype: option type to replace in @opt
1272 * @newopt: new option of type @newtype to replace (user-mem)
1273 *
1274 * Returns a new set of options which is a copy of @opt with the
1275 * option type @newtype replaced with @newopt.
1276 *
1277 * @opt may be NULL, in which case a new set of options is returned
1278 * containing just @newopt.
1279 *
1280 * @newopt may be NULL, in which case the specified option type is
1281 * not copied into the new set of options.
1282 *
1283 * The new set of options is allocated from the socket option memory
1284 * buffer of @sk.
1285 */
1286struct ipv6_txoptions *
1287ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1288 int newtype, struct ipv6_opt_hdr *newopt)
1289{
1290 int tot_len = 0;
1291 char *p;
1292 struct ipv6_txoptions *opt2;
1293
1294 if (opt) {
1295 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1296 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1297 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1298 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1299 if (newtype != IPV6_RTHDR && opt->srcrt)
1300 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1301 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1302 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1303 }
1304
1305 if (newopt)
1306 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1307
1308 if (!tot_len)
1309 return NULL;
1310
1311 tot_len += sizeof(*opt2);
1312 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1313 if (!opt2)
1314 return ERR_PTR(-ENOBUFS);
1315
1316 memset(opt2, 0, tot_len);
1317 refcount_set(&opt2->refcnt, 1);
1318 opt2->tot_len = tot_len;
1319 p = (char *)(opt2 + 1);
1320
1321 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1322 (opt ? opt->hopopt : NULL),
1323 newopt, newtype, &p);
1324 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1325 (opt ? opt->dst0opt : NULL),
1326 newopt, newtype, &p);
1327 ipv6_renew_option(IPV6_RTHDR,
1328 (struct ipv6_opt_hdr **)&opt2->srcrt,
1329 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1330 newopt, newtype, &p);
1331 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1332 (opt ? opt->dst1opt : NULL),
1333 newopt, newtype, &p);
1334
1335 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1336 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1337 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1338 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1339
1340 return opt2;
1341}
1342
1343struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1344 struct ipv6_txoptions *opt)
1345{
1346 /*
1347 * ignore the dest before srcrt unless srcrt is being included.
1348 * --yoshfuji
1349 */
1350 if (opt->dst0opt && !opt->srcrt) {
1351 if (opt_space != opt) {
1352 memcpy(opt_space, opt, sizeof(*opt_space));
1353 opt = opt_space;
1354 }
1355 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1356 opt->dst0opt = NULL;
1357 }
1358
1359 return opt;
1360}
1361EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
1362
1363/**
1364 * __fl6_update_dst - update flowi destination address with info given
1365 * by srcrt option, if any.
1366 *
1367 * @fl6: flowi6 for which daddr is to be updated
1368 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1369 * @orig: copy of original daddr address if modified
1370 *
1371 * Return: NULL if no srcrt or invalid srcrt type, otherwise returns orig
1372 * and initial value of fl6->daddr set in orig
1373 */
1374struct in6_addr *__fl6_update_dst(struct flowi6 *fl6,
1375 const struct ipv6_txoptions *opt,
1376 struct in6_addr *orig)
1377{
1378 if (!opt->srcrt)
1379 return NULL;
1380
1381 *orig = fl6->daddr;
1382
1383 switch (opt->srcrt->type) {
1384 case IPV6_SRCRT_TYPE_0:
1385 case IPV6_SRCRT_STRICT:
1386 case IPV6_SRCRT_TYPE_2:
1387 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1388 break;
1389 case IPV6_SRCRT_TYPE_4:
1390 {
1391 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1392
1393 fl6->daddr = srh->segments[srh->segments_left];
1394 break;
1395 }
1396 default:
1397 return NULL;
1398 }
1399
1400 return orig;
1401}
1402EXPORT_SYMBOL_GPL(__fl6_update_dst);