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
ip6_tlvopt_unknown(struct sk_buff * skb,int optoff,bool disallow_unknowns)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
ip6_parse_tlv(bool hopbyhop,struct sk_buff * skb,int max_count)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)
ipv6_dest_hao(struct sk_buff * skb,int optoff)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
ipv6_destopt_rcv(struct sk_buff * skb)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(dst)), 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 > READ_ONCE(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,
326 READ_ONCE(net->ipv6.sysctl.max_dst_opts_cnt))) {
327 skb->transport_header += extlen;
328 opt = IP6CB(skb);
329 #if IS_ENABLED(CONFIG_IPV6_MIP6)
330 opt->nhoff = dstbuf;
331 #else
332 opt->nhoff = opt->dst1;
333 #endif
334 return 1;
335 }
336
337 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
338 return -1;
339 }
340
seg6_update_csum(struct sk_buff * skb)341 static void seg6_update_csum(struct sk_buff *skb)
342 {
343 struct ipv6_sr_hdr *hdr;
344 struct in6_addr *addr;
345 __be32 from, to;
346
347 /* srh is at transport offset and seg_left is already decremented
348 * but daddr is not yet updated with next segment
349 */
350
351 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
352 addr = hdr->segments + hdr->segments_left;
353
354 hdr->segments_left++;
355 from = *(__be32 *)hdr;
356
357 hdr->segments_left--;
358 to = *(__be32 *)hdr;
359
360 /* update skb csum with diff resulting from seg_left decrement */
361
362 update_csum_diff4(skb, from, to);
363
364 /* compute csum diff between current and next segment and update */
365
366 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
367 (__be32 *)addr);
368 }
369
ipv6_srh_rcv(struct sk_buff * skb)370 static int ipv6_srh_rcv(struct sk_buff *skb)
371 {
372 struct inet6_skb_parm *opt = IP6CB(skb);
373 struct net *net = dev_net(skb->dev);
374 struct ipv6_sr_hdr *hdr;
375 struct inet6_dev *idev;
376 struct in6_addr *addr;
377 int accept_seg6;
378
379 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
380
381 idev = __in6_dev_get(skb->dev);
382 if (!idev) {
383 kfree_skb(skb);
384 return -1;
385 }
386
387 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled),
388 READ_ONCE(idev->cnf.seg6_enabled));
389
390 if (!accept_seg6) {
391 kfree_skb(skb);
392 return -1;
393 }
394
395 #ifdef CONFIG_IPV6_SEG6_HMAC
396 if (!seg6_hmac_validate_skb(skb)) {
397 kfree_skb(skb);
398 return -1;
399 }
400 #endif
401
402 looped_back:
403 if (hdr->segments_left == 0) {
404 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
405 int offset = (hdr->hdrlen + 1) << 3;
406
407 skb_postpull_rcsum(skb, skb_network_header(skb),
408 skb_network_header_len(skb));
409 skb_pull(skb, offset);
410 skb_postpull_rcsum(skb, skb_transport_header(skb),
411 offset);
412
413 skb_reset_network_header(skb);
414 skb_reset_transport_header(skb);
415 skb->encapsulation = 0;
416 if (hdr->nexthdr == NEXTHDR_IPV4)
417 skb->protocol = htons(ETH_P_IP);
418 __skb_tunnel_rx(skb, skb->dev, net);
419
420 netif_rx(skb);
421 return -1;
422 }
423
424 opt->srcrt = skb_network_header_len(skb);
425 opt->lastopt = opt->srcrt;
426 skb->transport_header += (hdr->hdrlen + 1) << 3;
427 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
428
429 return 1;
430 }
431
432 if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
433 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
434 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
435 ((&hdr->segments_left) -
436 skb_network_header(skb)));
437 return -1;
438 }
439
440 if (skb_cloned(skb)) {
441 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
442 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
443 IPSTATS_MIB_OUTDISCARDS);
444 kfree_skb(skb);
445 return -1;
446 }
447
448 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
449 }
450
451 hdr->segments_left--;
452 addr = hdr->segments + hdr->segments_left;
453
454 skb_push(skb, sizeof(struct ipv6hdr));
455
456 if (skb->ip_summed == CHECKSUM_COMPLETE)
457 seg6_update_csum(skb);
458
459 ipv6_hdr(skb)->daddr = *addr;
460
461 ip6_route_input(skb);
462
463 if (skb_dst(skb)->error) {
464 dst_input(skb);
465 return -1;
466 }
467
468 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
469 if (ipv6_hdr(skb)->hop_limit <= 1) {
470 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
471 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
472 ICMPV6_EXC_HOPLIMIT, 0);
473 kfree_skb(skb);
474 return -1;
475 }
476 ipv6_hdr(skb)->hop_limit--;
477
478 skb_pull(skb, sizeof(struct ipv6hdr));
479 goto looped_back;
480 }
481
482 dst_input(skb);
483
484 return -1;
485 }
486
ipv6_rpl_srh_rcv(struct sk_buff * skb)487 static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
488 {
489 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
490 struct inet6_skb_parm *opt = IP6CB(skb);
491 struct net *net = dev_net(skb->dev);
492 struct inet6_dev *idev;
493 struct ipv6hdr *oldhdr;
494 unsigned char *buf;
495 int accept_rpl_seg;
496 int i, err;
497 u64 n = 0;
498 u32 r;
499
500 idev = __in6_dev_get(skb->dev);
501
502 accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled),
503 READ_ONCE(idev->cnf.rpl_seg_enabled));
504 if (!accept_rpl_seg) {
505 kfree_skb(skb);
506 return -1;
507 }
508
509 looped_back:
510 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
511
512 if (hdr->segments_left == 0) {
513 if (hdr->nexthdr == NEXTHDR_IPV6) {
514 int offset = (hdr->hdrlen + 1) << 3;
515
516 skb_postpull_rcsum(skb, skb_network_header(skb),
517 skb_network_header_len(skb));
518 skb_pull(skb, offset);
519 skb_postpull_rcsum(skb, skb_transport_header(skb),
520 offset);
521
522 skb_reset_network_header(skb);
523 skb_reset_transport_header(skb);
524 skb->encapsulation = 0;
525
526 __skb_tunnel_rx(skb, skb->dev, net);
527
528 netif_rx(skb);
529 return -1;
530 }
531
532 opt->srcrt = skb_network_header_len(skb);
533 opt->lastopt = opt->srcrt;
534 skb->transport_header += (hdr->hdrlen + 1) << 3;
535 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
536
537 return 1;
538 }
539
540 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
541 r = do_div(n, (16 - hdr->cmpri));
542 /* checks if calculation was without remainder and n fits into
543 * unsigned char which is segments_left field. Should not be
544 * higher than that.
545 */
546 if (r || (n + 1) > 255) {
547 kfree_skb(skb);
548 return -1;
549 }
550
551 if (hdr->segments_left > n + 1) {
552 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
553 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
554 ((&hdr->segments_left) -
555 skb_network_header(skb)));
556 return -1;
557 }
558
559 hdr->segments_left--;
560 i = n - hdr->segments_left;
561
562 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
563 if (unlikely(!buf)) {
564 kfree_skb(skb);
565 return -1;
566 }
567
568 ohdr = (struct ipv6_rpl_sr_hdr *)buf;
569 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
570 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
571
572 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
573 kfree_skb(skb);
574 kfree(buf);
575 return -1;
576 }
577
578 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
579 if (err) {
580 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
581 kfree_skb(skb);
582 kfree(buf);
583 return -1;
584 }
585
586 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
587
588 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
589
590 oldhdr = ipv6_hdr(skb);
591
592 skb_pull(skb, ((hdr->hdrlen + 1) << 3));
593 skb_postpull_rcsum(skb, oldhdr,
594 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
595 if (unlikely(!hdr->segments_left)) {
596 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
597 GFP_ATOMIC)) {
598 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
599 kfree_skb(skb);
600 kfree(buf);
601 return -1;
602 }
603
604 oldhdr = ipv6_hdr(skb);
605 }
606 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
607 skb_reset_network_header(skb);
608 skb_mac_header_rebuild(skb);
609 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
610
611 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
612 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
613
614 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
615 skb_postpush_rcsum(skb, ipv6_hdr(skb),
616 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
617
618 kfree(buf);
619
620 ip6_route_input(skb);
621
622 if (skb_dst(skb)->error) {
623 dst_input(skb);
624 return -1;
625 }
626
627 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
628 if (ipv6_hdr(skb)->hop_limit <= 1) {
629 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
630 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
631 ICMPV6_EXC_HOPLIMIT, 0);
632 kfree_skb(skb);
633 return -1;
634 }
635 ipv6_hdr(skb)->hop_limit--;
636
637 skb_pull(skb, sizeof(struct ipv6hdr));
638 goto looped_back;
639 }
640
641 dst_input(skb);
642
643 return -1;
644 }
645
646 /********************************
647 Routing header.
648 ********************************/
649
650 /* called with rcu_read_lock() */
ipv6_rthdr_rcv(struct sk_buff * skb)651 static int ipv6_rthdr_rcv(struct sk_buff *skb)
652 {
653 struct inet6_dev *idev = __in6_dev_get(skb->dev);
654 struct inet6_skb_parm *opt = IP6CB(skb);
655 struct in6_addr *addr = NULL;
656 int n, i;
657 struct ipv6_rt_hdr *hdr;
658 struct rt0_hdr *rthdr;
659 struct net *net = dev_net(skb->dev);
660 int accept_source_route;
661
662 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
663
664 if (idev)
665 accept_source_route = min(accept_source_route,
666 READ_ONCE(idev->cnf.accept_source_route));
667
668 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
669 !pskb_may_pull(skb, (skb_transport_offset(skb) +
670 ((skb_transport_header(skb)[1] + 1) << 3)))) {
671 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
672 kfree_skb(skb);
673 return -1;
674 }
675
676 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
677
678 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
679 skb->pkt_type != PACKET_HOST) {
680 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
681 kfree_skb(skb);
682 return -1;
683 }
684
685 switch (hdr->type) {
686 case IPV6_SRCRT_TYPE_4:
687 /* segment routing */
688 return ipv6_srh_rcv(skb);
689 case IPV6_SRCRT_TYPE_3:
690 /* rpl segment routing */
691 return ipv6_rpl_srh_rcv(skb);
692 default:
693 break;
694 }
695
696 looped_back:
697 if (hdr->segments_left == 0) {
698 switch (hdr->type) {
699 #if IS_ENABLED(CONFIG_IPV6_MIP6)
700 case IPV6_SRCRT_TYPE_2:
701 /* Silently discard type 2 header unless it was
702 * processed by own
703 */
704 if (!addr) {
705 __IP6_INC_STATS(net, idev,
706 IPSTATS_MIB_INADDRERRORS);
707 kfree_skb(skb);
708 return -1;
709 }
710 break;
711 #endif
712 default:
713 break;
714 }
715
716 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
717 skb->transport_header += (hdr->hdrlen + 1) << 3;
718 opt->dst0 = opt->dst1;
719 opt->dst1 = 0;
720 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
721 return 1;
722 }
723
724 switch (hdr->type) {
725 #if IS_ENABLED(CONFIG_IPV6_MIP6)
726 case IPV6_SRCRT_TYPE_2:
727 if (accept_source_route < 0)
728 goto unknown_rh;
729 /* Silently discard invalid RTH type 2 */
730 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
731 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
732 kfree_skb(skb);
733 return -1;
734 }
735 break;
736 #endif
737 default:
738 goto unknown_rh;
739 }
740
741 /*
742 * This is the routing header forwarding algorithm from
743 * RFC 2460, page 16.
744 */
745
746 n = hdr->hdrlen >> 1;
747
748 if (hdr->segments_left > n) {
749 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
750 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
751 ((&hdr->segments_left) -
752 skb_network_header(skb)));
753 return -1;
754 }
755
756 /* We are about to mangle packet header. Be careful!
757 Do not damage packets queued somewhere.
758 */
759 if (skb_cloned(skb)) {
760 /* the copy is a forwarded packet */
761 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
762 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
763 IPSTATS_MIB_OUTDISCARDS);
764 kfree_skb(skb);
765 return -1;
766 }
767 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
768 }
769
770 if (skb->ip_summed == CHECKSUM_COMPLETE)
771 skb->ip_summed = CHECKSUM_NONE;
772
773 i = n - --hdr->segments_left;
774
775 rthdr = (struct rt0_hdr *) hdr;
776 addr = rthdr->addr;
777 addr += i - 1;
778
779 switch (hdr->type) {
780 #if IS_ENABLED(CONFIG_IPV6_MIP6)
781 case IPV6_SRCRT_TYPE_2:
782 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
783 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
784 IPPROTO_ROUTING) < 0) {
785 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
786 kfree_skb(skb);
787 return -1;
788 }
789 if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) {
790 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
791 kfree_skb(skb);
792 return -1;
793 }
794 break;
795 #endif
796 default:
797 break;
798 }
799
800 if (ipv6_addr_is_multicast(addr)) {
801 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
802 kfree_skb(skb);
803 return -1;
804 }
805
806 swap(*addr, ipv6_hdr(skb)->daddr);
807
808 ip6_route_input(skb);
809 if (skb_dst(skb)->error) {
810 skb_push(skb, -skb_network_offset(skb));
811 dst_input(skb);
812 return -1;
813 }
814
815 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
816 if (ipv6_hdr(skb)->hop_limit <= 1) {
817 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
818 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
819 0);
820 kfree_skb(skb);
821 return -1;
822 }
823 ipv6_hdr(skb)->hop_limit--;
824 goto looped_back;
825 }
826
827 skb_push(skb, -skb_network_offset(skb));
828 dst_input(skb);
829 return -1;
830
831 unknown_rh:
832 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
833 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
834 (&hdr->type) - skb_network_header(skb));
835 return -1;
836 }
837
838 static const struct inet6_protocol rthdr_protocol = {
839 .handler = ipv6_rthdr_rcv,
840 .flags = INET6_PROTO_NOPOLICY,
841 };
842
843 static const struct inet6_protocol destopt_protocol = {
844 .handler = ipv6_destopt_rcv,
845 .flags = INET6_PROTO_NOPOLICY,
846 };
847
848 static const struct inet6_protocol nodata_protocol = {
849 .handler = dst_discard,
850 .flags = INET6_PROTO_NOPOLICY,
851 };
852
ipv6_exthdrs_init(void)853 int __init ipv6_exthdrs_init(void)
854 {
855 int ret;
856
857 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
858 if (ret)
859 goto out;
860
861 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
862 if (ret)
863 goto out_rthdr;
864
865 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
866 if (ret)
867 goto out_destopt;
868
869 out:
870 return ret;
871 out_destopt:
872 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
873 out_rthdr:
874 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
875 goto out;
876 };
877
ipv6_exthdrs_exit(void)878 void ipv6_exthdrs_exit(void)
879 {
880 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
881 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
882 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
883 }
884
885 /**********************************
886 Hop-by-hop options.
887 **********************************/
888
889 /* Router Alert as of RFC 2711 */
890
ipv6_hop_ra(struct sk_buff * skb,int optoff)891 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
892 {
893 const unsigned char *nh = skb_network_header(skb);
894
895 if (nh[optoff + 1] == 2) {
896 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
897 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
898 return true;
899 }
900 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
901 nh[optoff + 1]);
902 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
903 return false;
904 }
905
906 /* IOAM */
907
ipv6_hop_ioam(struct sk_buff * skb,int optoff)908 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
909 {
910 struct ioam6_trace_hdr *trace;
911 struct ioam6_namespace *ns;
912 struct ioam6_hdr *hdr;
913
914 /* Bad alignment (must be 4n-aligned) */
915 if (optoff & 3)
916 goto drop;
917
918 /* Ignore if IOAM is not enabled on ingress */
919 if (!READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_enabled))
920 goto ignore;
921
922 /* Truncated Option header */
923 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
924 if (hdr->opt_len < 2)
925 goto drop;
926
927 switch (hdr->type) {
928 case IOAM6_TYPE_PREALLOC:
929 /* Truncated Pre-allocated Trace header */
930 if (hdr->opt_len < 2 + sizeof(*trace))
931 goto drop;
932
933 /* Malformed Pre-allocated Trace header */
934 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
935 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
936 goto drop;
937
938 /* Inconsistent Pre-allocated Trace header */
939 if (trace->nodelen !=
940 ioam6_trace_compute_nodelen(be32_to_cpu(trace->type_be32)))
941 goto drop;
942
943 /* Ignore if the IOAM namespace is unknown */
944 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id);
945 if (!ns)
946 goto ignore;
947
948 if (!skb_valid_dst(skb))
949 ip6_route_input(skb);
950
951 /* About to mangle packet header */
952 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
953 goto drop;
954
955 /* Trace pointer may have changed */
956 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb)
957 + optoff + sizeof(*hdr));
958
959 ioam6_fill_trace_data(skb, ns, trace, true);
960
961 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev),
962 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2);
963 break;
964 default:
965 break;
966 }
967
968 ignore:
969 return true;
970
971 drop:
972 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
973 return false;
974 }
975
976 /* Jumbo payload */
977
ipv6_hop_jumbo(struct sk_buff * skb,int optoff)978 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
979 {
980 const unsigned char *nh = skb_network_header(skb);
981 SKB_DR(reason);
982 u32 pkt_len;
983
984 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
985 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
986 nh[optoff+1]);
987 SKB_DR_SET(reason, IP_INHDR);
988 goto drop;
989 }
990
991 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
992 if (pkt_len <= IPV6_MAXPLEN) {
993 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
994 SKB_DROP_REASON_IP_INHDR);
995 return false;
996 }
997 if (ipv6_hdr(skb)->payload_len) {
998 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
999 SKB_DROP_REASON_IP_INHDR);
1000 return false;
1001 }
1002
1003 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
1004 SKB_DR_SET(reason, PKT_TOO_SMALL);
1005 goto drop;
1006 }
1007
1008 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1009 goto drop;
1010
1011 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1012 return true;
1013
1014 drop:
1015 kfree_skb_reason(skb, reason);
1016 return false;
1017 }
1018
1019 /* CALIPSO RFC 5570 */
1020
ipv6_hop_calipso(struct sk_buff * skb,int optoff)1021 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1022 {
1023 const unsigned char *nh = skb_network_header(skb);
1024
1025 if (nh[optoff + 1] < 8)
1026 goto drop;
1027
1028 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1029 goto drop;
1030
1031 if (!calipso_validate(skb, nh + optoff))
1032 goto drop;
1033
1034 return true;
1035
1036 drop:
1037 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1038 return false;
1039 }
1040
ipv6_parse_hopopts(struct sk_buff * skb)1041 int ipv6_parse_hopopts(struct sk_buff *skb)
1042 {
1043 struct inet6_skb_parm *opt = IP6CB(skb);
1044 struct net *net = dev_net(skb->dev);
1045 int extlen;
1046
1047 /*
1048 * skb_network_header(skb) is equal to skb->data, and
1049 * skb_network_header_len(skb) is always equal to
1050 * sizeof(struct ipv6hdr) by definition of
1051 * hop-by-hop options.
1052 */
1053 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1054 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1055 ((skb_transport_header(skb)[1] + 1) << 3)))) {
1056 fail_and_free:
1057 kfree_skb(skb);
1058 return -1;
1059 }
1060
1061 extlen = (skb_transport_header(skb)[1] + 1) << 3;
1062 if (extlen > READ_ONCE(net->ipv6.sysctl.max_hbh_opts_len))
1063 goto fail_and_free;
1064
1065 opt->flags |= IP6SKB_HOPBYHOP;
1066 if (ip6_parse_tlv(true, skb,
1067 READ_ONCE(net->ipv6.sysctl.max_hbh_opts_cnt))) {
1068 skb->transport_header += extlen;
1069 opt = IP6CB(skb);
1070 opt->nhoff = sizeof(struct ipv6hdr);
1071 return 1;
1072 }
1073 return -1;
1074 }
1075
1076 /*
1077 * Creating outbound headers.
1078 *
1079 * "build" functions work when skb is filled from head to tail (datagram)
1080 * "push" functions work when headers are added from tail to head (tcp)
1081 *
1082 * In both cases we assume, that caller reserved enough room
1083 * for headers.
1084 */
1085
ipv6_push_rthdr0(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1086 static u8 ipv6_push_rthdr0(struct sk_buff *skb, u8 proto,
1087 struct ipv6_rt_hdr *opt,
1088 struct in6_addr **addr_p, struct in6_addr *saddr)
1089 {
1090 struct rt0_hdr *phdr, *ihdr;
1091 int hops;
1092
1093 ihdr = (struct rt0_hdr *) opt;
1094
1095 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1096 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1097
1098 hops = ihdr->rt_hdr.hdrlen >> 1;
1099
1100 if (hops > 1)
1101 memcpy(phdr->addr, ihdr->addr + 1,
1102 (hops - 1) * sizeof(struct in6_addr));
1103
1104 phdr->addr[hops - 1] = **addr_p;
1105 *addr_p = ihdr->addr;
1106
1107 phdr->rt_hdr.nexthdr = proto;
1108 return NEXTHDR_ROUTING;
1109 }
1110
ipv6_push_rthdr4(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1111 static u8 ipv6_push_rthdr4(struct sk_buff *skb, u8 proto,
1112 struct ipv6_rt_hdr *opt,
1113 struct in6_addr **addr_p, struct in6_addr *saddr)
1114 {
1115 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1116 int plen, hops;
1117
1118 sr_ihdr = (struct ipv6_sr_hdr *)opt;
1119 plen = (sr_ihdr->hdrlen + 1) << 3;
1120
1121 sr_phdr = skb_push(skb, plen);
1122 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1123
1124 hops = sr_ihdr->first_segment + 1;
1125 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1126 (hops - 1) * sizeof(struct in6_addr));
1127
1128 sr_phdr->segments[0] = **addr_p;
1129 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1130
1131 if (sr_ihdr->hdrlen > hops * 2) {
1132 int tlvs_offset, tlvs_length;
1133
1134 tlvs_offset = (1 + hops * 2) << 3;
1135 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1136 memcpy((char *)sr_phdr + tlvs_offset,
1137 (char *)sr_ihdr + tlvs_offset, tlvs_length);
1138 }
1139
1140 #ifdef CONFIG_IPV6_SEG6_HMAC
1141 if (sr_has_hmac(sr_phdr)) {
1142 struct net *net = NULL;
1143
1144 if (skb->dev)
1145 net = dev_net(skb->dev);
1146 else if (skb->sk)
1147 net = sock_net(skb->sk);
1148
1149 WARN_ON(!net);
1150
1151 if (net)
1152 seg6_push_hmac(net, saddr, sr_phdr);
1153 }
1154 #endif
1155
1156 sr_phdr->nexthdr = proto;
1157 return NEXTHDR_ROUTING;
1158 }
1159
ipv6_push_rthdr(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1160 static u8 ipv6_push_rthdr(struct sk_buff *skb, u8 proto,
1161 struct ipv6_rt_hdr *opt,
1162 struct in6_addr **addr_p, struct in6_addr *saddr)
1163 {
1164 switch (opt->type) {
1165 case IPV6_SRCRT_TYPE_0:
1166 case IPV6_SRCRT_STRICT:
1167 case IPV6_SRCRT_TYPE_2:
1168 proto = ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1169 break;
1170 case IPV6_SRCRT_TYPE_4:
1171 proto = ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1172 break;
1173 default:
1174 break;
1175 }
1176 return proto;
1177 }
1178
ipv6_push_exthdr(struct sk_buff * skb,u8 proto,u8 type,struct ipv6_opt_hdr * opt)1179 static u8 ipv6_push_exthdr(struct sk_buff *skb, u8 proto, u8 type, struct ipv6_opt_hdr *opt)
1180 {
1181 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1182
1183 memcpy(h, opt, ipv6_optlen(opt));
1184 h->nexthdr = proto;
1185 return type;
1186 }
1187
ipv6_push_nfrag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 proto,struct in6_addr ** daddr,struct in6_addr * saddr)1188 u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1189 u8 proto,
1190 struct in6_addr **daddr, struct in6_addr *saddr)
1191 {
1192 if (opt->srcrt) {
1193 proto = ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1194 /*
1195 * IPV6_RTHDRDSTOPTS is ignored
1196 * unless IPV6_RTHDR is set (RFC3542).
1197 */
1198 if (opt->dst0opt)
1199 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1200 }
1201 if (opt->hopopt)
1202 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1203 return proto;
1204 }
1205
ipv6_push_frag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 proto)1206 u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 proto)
1207 {
1208 if (opt->dst1opt)
1209 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1210 return proto;
1211 }
1212 EXPORT_SYMBOL(ipv6_push_frag_opts);
1213
1214 struct ipv6_txoptions *
ipv6_dup_options(struct sock * sk,struct ipv6_txoptions * opt)1215 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1216 {
1217 struct ipv6_txoptions *opt2;
1218
1219 opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC);
1220 if (opt2) {
1221 long dif = (char *)opt2 - (char *)opt;
1222 if (opt2->hopopt)
1223 *((char **)&opt2->hopopt) += dif;
1224 if (opt2->dst0opt)
1225 *((char **)&opt2->dst0opt) += dif;
1226 if (opt2->dst1opt)
1227 *((char **)&opt2->dst1opt) += dif;
1228 if (opt2->srcrt)
1229 *((char **)&opt2->srcrt) += dif;
1230 refcount_set(&opt2->refcnt, 1);
1231 }
1232 return opt2;
1233 }
1234 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1235
ipv6_renew_option(int renewtype,struct ipv6_opt_hdr ** dest,struct ipv6_opt_hdr * old,struct ipv6_opt_hdr * new,int newtype,char ** p)1236 static void ipv6_renew_option(int renewtype,
1237 struct ipv6_opt_hdr **dest,
1238 struct ipv6_opt_hdr *old,
1239 struct ipv6_opt_hdr *new,
1240 int newtype, char **p)
1241 {
1242 struct ipv6_opt_hdr *src;
1243
1244 src = (renewtype == newtype ? new : old);
1245 if (!src)
1246 return;
1247
1248 memcpy(*p, src, ipv6_optlen(src));
1249 *dest = (struct ipv6_opt_hdr *)*p;
1250 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1251 }
1252
1253 /**
1254 * ipv6_renew_options - replace a specific ext hdr with a new one.
1255 *
1256 * @sk: sock from which to allocate memory
1257 * @opt: original options
1258 * @newtype: option type to replace in @opt
1259 * @newopt: new option of type @newtype to replace (user-mem)
1260 *
1261 * Returns a new set of options which is a copy of @opt with the
1262 * option type @newtype replaced with @newopt.
1263 *
1264 * @opt may be NULL, in which case a new set of options is returned
1265 * containing just @newopt.
1266 *
1267 * @newopt may be NULL, in which case the specified option type is
1268 * not copied into the new set of options.
1269 *
1270 * The new set of options is allocated from the socket option memory
1271 * buffer of @sk.
1272 */
1273 struct ipv6_txoptions *
ipv6_renew_options(struct sock * sk,struct ipv6_txoptions * opt,int newtype,struct ipv6_opt_hdr * newopt)1274 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1275 int newtype, struct ipv6_opt_hdr *newopt)
1276 {
1277 int tot_len = 0;
1278 char *p;
1279 struct ipv6_txoptions *opt2;
1280
1281 if (opt) {
1282 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1283 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1284 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1285 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1286 if (newtype != IPV6_RTHDR && opt->srcrt)
1287 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1288 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1289 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1290 }
1291
1292 if (newopt)
1293 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1294
1295 if (!tot_len)
1296 return NULL;
1297
1298 tot_len += sizeof(*opt2);
1299 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1300 if (!opt2)
1301 return ERR_PTR(-ENOBUFS);
1302
1303 memset(opt2, 0, tot_len);
1304 refcount_set(&opt2->refcnt, 1);
1305 opt2->tot_len = tot_len;
1306 p = (char *)(opt2 + 1);
1307
1308 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1309 (opt ? opt->hopopt : NULL),
1310 newopt, newtype, &p);
1311 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1312 (opt ? opt->dst0opt : NULL),
1313 newopt, newtype, &p);
1314 ipv6_renew_option(IPV6_RTHDR,
1315 (struct ipv6_opt_hdr **)&opt2->srcrt,
1316 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1317 newopt, newtype, &p);
1318 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1319 (opt ? opt->dst1opt : NULL),
1320 newopt, newtype, &p);
1321
1322 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1323 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1324 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1325 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1326
1327 return opt2;
1328 }
1329
__ipv6_fixup_options(struct ipv6_txoptions * opt_space,struct ipv6_txoptions * opt)1330 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1331 struct ipv6_txoptions *opt)
1332 {
1333 /*
1334 * ignore the dest before srcrt unless srcrt is being included.
1335 * --yoshfuji
1336 */
1337 if (opt->dst0opt && !opt->srcrt) {
1338 if (opt_space != opt) {
1339 memcpy(opt_space, opt, sizeof(*opt_space));
1340 opt = opt_space;
1341 }
1342 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1343 opt->dst0opt = NULL;
1344 }
1345
1346 return opt;
1347 }
1348 EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
1349
1350 /**
1351 * __fl6_update_dst - update flowi destination address with info given
1352 * by srcrt option, if any.
1353 *
1354 * @fl6: flowi6 for which daddr is to be updated
1355 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1356 * @orig: copy of original daddr address if modified
1357 *
1358 * Return: NULL if no srcrt or invalid srcrt type, otherwise returns orig
1359 * and initial value of fl6->daddr set in orig
1360 */
__fl6_update_dst(struct flowi6 * fl6,const struct ipv6_txoptions * opt,struct in6_addr * orig)1361 struct in6_addr *__fl6_update_dst(struct flowi6 *fl6,
1362 const struct ipv6_txoptions *opt,
1363 struct in6_addr *orig)
1364 {
1365 if (!opt->srcrt)
1366 return NULL;
1367
1368 *orig = fl6->daddr;
1369
1370 switch (opt->srcrt->type) {
1371 case IPV6_SRCRT_TYPE_0:
1372 case IPV6_SRCRT_STRICT:
1373 case IPV6_SRCRT_TYPE_2:
1374 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1375 break;
1376 case IPV6_SRCRT_TYPE_4:
1377 {
1378 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1379
1380 fl6->daddr = srh->segments[srh->segments_left];
1381 break;
1382 }
1383 default:
1384 return NULL;
1385 }
1386
1387 return orig;
1388 }
1389 EXPORT_SYMBOL_GPL(__fl6_update_dst);
1390