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
65 static 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
99 drop:
100 kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO);
101 return false;
102 }
103
104 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
105 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
106 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
107 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
108 #if IS_ENABLED(CONFIG_IPV6_MIP6)
109 static 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
114 static 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;
221 bad:
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)
231 static 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
295 static 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);
311 fail_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
340 static 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
369 static 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
397 looped_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
482 static 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
506 looped_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() */
648 static 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
693 looped_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
828 unknown_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
835 static const struct inet6_protocol rthdr_protocol = {
836 .handler = ipv6_rthdr_rcv,
837 .flags = INET6_PROTO_NOPOLICY,
838 };
839
840 static const struct inet6_protocol destopt_protocol = {
841 .handler = ipv6_destopt_rcv,
842 .flags = INET6_PROTO_NOPOLICY,
843 };
844
845 static const struct inet6_protocol nodata_protocol = {
846 .handler = dst_discard,
847 .flags = INET6_PROTO_NOPOLICY,
848 };
849
850 int __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
866 out:
867 return ret;
868 out_destopt:
869 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
870 out_rthdr:
871 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
872 goto out;
873 };
874
875 void 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
888 static 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
905 static 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
960 ignore:
961 return true;
962
963 drop:
964 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
965 return false;
966 }
967
968 /* Jumbo payload */
969
970 static 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
1006 drop:
1007 kfree_skb_reason(skb, reason);
1008 return false;
1009 }
1010
1011 /* CALIPSO RFC 5570 */
1012
1013 static 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
1028 drop:
1029 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1030 return false;
1031 }
1032
1033 int 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)))) {
1048 fail_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
1077 static 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
1102 static 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
1151 static 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
1169 static 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
1178 void 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
1195 void 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 }
1200 EXPORT_SYMBOL(ipv6_push_frag_opts);
1201
1202 struct ipv6_txoptions *
1203 ipv6_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 }
1223 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1224
1225 static 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 */
1262 struct ipv6_txoptions *
1263 ipv6_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
1319 struct 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 }
1337 EXPORT_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 */
1350 struct 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 }
1378 EXPORT_SYMBOL_GPL(fl6_update_dst);
1379
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