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 int chdr_len;
495 unsigned char *buf;
496 int accept_rpl_seg;
497 int i, err;
498 u64 n = 0;
499 u32 r;
500
501 idev = __in6_dev_get(skb->dev);
502
503 accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled),
504 READ_ONCE(idev->cnf.rpl_seg_enabled));
505 if (!accept_rpl_seg) {
506 kfree_skb(skb);
507 return -1;
508 }
509
510 looped_back:
511 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
512
513 if (hdr->segments_left == 0) {
514 if (hdr->nexthdr == NEXTHDR_IPV6) {
515 int offset = (hdr->hdrlen + 1) << 3;
516
517 skb_postpull_rcsum(skb, skb_network_header(skb),
518 skb_network_header_len(skb));
519 skb_pull(skb, offset);
520 skb_postpull_rcsum(skb, skb_transport_header(skb),
521 offset);
522
523 skb_reset_network_header(skb);
524 skb_reset_transport_header(skb);
525 skb->encapsulation = 0;
526
527 __skb_tunnel_rx(skb, skb->dev, net);
528
529 netif_rx(skb);
530 return -1;
531 }
532
533 opt->srcrt = skb_network_header_len(skb);
534 opt->lastopt = opt->srcrt;
535 skb->transport_header += (hdr->hdrlen + 1) << 3;
536 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
537
538 return 1;
539 }
540
541 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
542 r = do_div(n, (16 - hdr->cmpri));
543 /* checks if calculation was without remainder and n fits into
544 * unsigned char which is segments_left field. Should not be
545 * higher than that.
546 */
547 if (r || (n + 1) > 255) {
548 kfree_skb(skb);
549 return -1;
550 }
551
552 if (hdr->segments_left > n + 1) {
553 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
554 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
555 ((&hdr->segments_left) -
556 skb_network_header(skb)));
557 return -1;
558 }
559
560 hdr->segments_left--;
561 i = n - hdr->segments_left;
562
563 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
564 if (unlikely(!buf)) {
565 kfree_skb(skb);
566 return -1;
567 }
568
569 ohdr = (struct ipv6_rpl_sr_hdr *)buf;
570 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
571 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
572
573 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
574 kfree_skb(skb);
575 kfree(buf);
576 return -1;
577 }
578
579 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
580 if (err) {
581 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
582 kfree_skb(skb);
583 kfree(buf);
584 return -1;
585 }
586
587 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
588
589 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
590
591 oldhdr = ipv6_hdr(skb);
592
593 skb_pull(skb, ((hdr->hdrlen + 1) << 3));
594 skb_postpull_rcsum(skb, oldhdr,
595 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
596 chdr_len = sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3);
597 if (unlikely(!hdr->segments_left ||
598 skb_headroom(skb) < chdr_len + skb->mac_len)) {
599 if (pskb_expand_head(skb, chdr_len + skb->mac_len, 0,
600 GFP_ATOMIC)) {
601 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
602 kfree_skb(skb);
603 kfree(buf);
604 return -1;
605 }
606
607 oldhdr = ipv6_hdr(skb);
608 }
609 skb_push(skb, chdr_len);
610 skb_reset_network_header(skb);
611 skb_mac_header_rebuild(skb);
612 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
613
614 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
615 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
616
617 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
618 skb_postpush_rcsum(skb, ipv6_hdr(skb),
619 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
620
621 kfree(buf);
622
623 ip6_route_input(skb);
624
625 if (skb_dst(skb)->error) {
626 dst_input(skb);
627 return -1;
628 }
629
630 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
631 if (ipv6_hdr(skb)->hop_limit <= 1) {
632 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
633 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
634 ICMPV6_EXC_HOPLIMIT, 0);
635 kfree_skb(skb);
636 return -1;
637 }
638 ipv6_hdr(skb)->hop_limit--;
639
640 skb_pull(skb, sizeof(struct ipv6hdr));
641 goto looped_back;
642 }
643
644 dst_input(skb);
645
646 return -1;
647 }
648
649 /********************************
650 Routing header.
651 ********************************/
652
653 /* called with rcu_read_lock() */
ipv6_rthdr_rcv(struct sk_buff * skb)654 static int ipv6_rthdr_rcv(struct sk_buff *skb)
655 {
656 struct inet6_dev *idev = __in6_dev_get(skb->dev);
657 struct inet6_skb_parm *opt = IP6CB(skb);
658 struct in6_addr *addr = NULL;
659 int n, i;
660 struct ipv6_rt_hdr *hdr;
661 struct rt0_hdr *rthdr;
662 struct net *net = dev_net(skb->dev);
663 int accept_source_route;
664
665 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
666
667 if (idev)
668 accept_source_route = min(accept_source_route,
669 READ_ONCE(idev->cnf.accept_source_route));
670
671 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
672 !pskb_may_pull(skb, (skb_transport_offset(skb) +
673 ((skb_transport_header(skb)[1] + 1) << 3)))) {
674 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
675 kfree_skb(skb);
676 return -1;
677 }
678
679 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
680
681 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
682 skb->pkt_type != PACKET_HOST) {
683 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
684 kfree_skb(skb);
685 return -1;
686 }
687
688 switch (hdr->type) {
689 case IPV6_SRCRT_TYPE_4:
690 /* segment routing */
691 return ipv6_srh_rcv(skb);
692 case IPV6_SRCRT_TYPE_3:
693 /* rpl segment routing */
694 return ipv6_rpl_srh_rcv(skb);
695 default:
696 break;
697 }
698
699 looped_back:
700 if (hdr->segments_left == 0) {
701 switch (hdr->type) {
702 #if IS_ENABLED(CONFIG_IPV6_MIP6)
703 case IPV6_SRCRT_TYPE_2:
704 /* Silently discard type 2 header unless it was
705 * processed by own
706 */
707 if (!addr) {
708 __IP6_INC_STATS(net, idev,
709 IPSTATS_MIB_INADDRERRORS);
710 kfree_skb(skb);
711 return -1;
712 }
713 break;
714 #endif
715 default:
716 break;
717 }
718
719 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
720 skb->transport_header += (hdr->hdrlen + 1) << 3;
721 opt->dst0 = opt->dst1;
722 opt->dst1 = 0;
723 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
724 return 1;
725 }
726
727 switch (hdr->type) {
728 #if IS_ENABLED(CONFIG_IPV6_MIP6)
729 case IPV6_SRCRT_TYPE_2:
730 if (accept_source_route < 0)
731 goto unknown_rh;
732 /* Silently discard invalid RTH type 2 */
733 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
734 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
735 kfree_skb(skb);
736 return -1;
737 }
738 break;
739 #endif
740 default:
741 goto unknown_rh;
742 }
743
744 /*
745 * This is the routing header forwarding algorithm from
746 * RFC 2460, page 16.
747 */
748
749 n = hdr->hdrlen >> 1;
750
751 if (hdr->segments_left > n) {
752 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
753 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
754 ((&hdr->segments_left) -
755 skb_network_header(skb)));
756 return -1;
757 }
758
759 /* We are about to mangle packet header. Be careful!
760 Do not damage packets queued somewhere.
761 */
762 if (skb_cloned(skb)) {
763 /* the copy is a forwarded packet */
764 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
765 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
766 IPSTATS_MIB_OUTDISCARDS);
767 kfree_skb(skb);
768 return -1;
769 }
770 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
771 }
772
773 if (skb->ip_summed == CHECKSUM_COMPLETE)
774 skb->ip_summed = CHECKSUM_NONE;
775
776 i = n - --hdr->segments_left;
777
778 rthdr = (struct rt0_hdr *) hdr;
779 addr = rthdr->addr;
780 addr += i - 1;
781
782 switch (hdr->type) {
783 #if IS_ENABLED(CONFIG_IPV6_MIP6)
784 case IPV6_SRCRT_TYPE_2:
785 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
786 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
787 IPPROTO_ROUTING) < 0) {
788 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
789 kfree_skb(skb);
790 return -1;
791 }
792 if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) {
793 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
794 kfree_skb(skb);
795 return -1;
796 }
797 break;
798 #endif
799 default:
800 break;
801 }
802
803 if (ipv6_addr_is_multicast(addr)) {
804 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
805 kfree_skb(skb);
806 return -1;
807 }
808
809 swap(*addr, ipv6_hdr(skb)->daddr);
810
811 ip6_route_input(skb);
812 if (skb_dst(skb)->error) {
813 skb_push(skb, -skb_network_offset(skb));
814 dst_input(skb);
815 return -1;
816 }
817
818 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
819 if (ipv6_hdr(skb)->hop_limit <= 1) {
820 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
821 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
822 0);
823 kfree_skb(skb);
824 return -1;
825 }
826 ipv6_hdr(skb)->hop_limit--;
827 goto looped_back;
828 }
829
830 skb_push(skb, -skb_network_offset(skb));
831 dst_input(skb);
832 return -1;
833
834 unknown_rh:
835 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
836 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
837 (&hdr->type) - skb_network_header(skb));
838 return -1;
839 }
840
841 static const struct inet6_protocol rthdr_protocol = {
842 .handler = ipv6_rthdr_rcv,
843 .flags = INET6_PROTO_NOPOLICY,
844 };
845
846 static const struct inet6_protocol destopt_protocol = {
847 .handler = ipv6_destopt_rcv,
848 .flags = INET6_PROTO_NOPOLICY,
849 };
850
851 static const struct inet6_protocol nodata_protocol = {
852 .handler = dst_discard,
853 .flags = INET6_PROTO_NOPOLICY,
854 };
855
ipv6_exthdrs_init(void)856 int __init ipv6_exthdrs_init(void)
857 {
858 int ret;
859
860 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
861 if (ret)
862 goto out;
863
864 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
865 if (ret)
866 goto out_rthdr;
867
868 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
869 if (ret)
870 goto out_destopt;
871
872 out:
873 return ret;
874 out_destopt:
875 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
876 out_rthdr:
877 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
878 goto out;
879 };
880
ipv6_exthdrs_exit(void)881 void ipv6_exthdrs_exit(void)
882 {
883 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
884 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
885 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
886 }
887
888 /**********************************
889 Hop-by-hop options.
890 **********************************/
891
892 /* Router Alert as of RFC 2711 */
893
ipv6_hop_ra(struct sk_buff * skb,int optoff)894 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
895 {
896 const unsigned char *nh = skb_network_header(skb);
897
898 if (nh[optoff + 1] == 2) {
899 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
900 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
901 return true;
902 }
903 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
904 nh[optoff + 1]);
905 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
906 return false;
907 }
908
909 /* IOAM */
910
ipv6_hop_ioam(struct sk_buff * skb,int optoff)911 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
912 {
913 enum skb_drop_reason drop_reason;
914 struct ioam6_trace_hdr *trace;
915 struct ioam6_namespace *ns;
916 struct inet6_dev *idev;
917 struct ioam6_hdr *hdr;
918
919 drop_reason = SKB_DROP_REASON_IP_INHDR;
920
921 /* Bad alignment (must be 4n-aligned) */
922 if (optoff & 3)
923 goto drop;
924
925 /* Does the device still have IPv6 configuration? */
926 idev = __in6_dev_get(skb->dev);
927 if (!idev) {
928 drop_reason = SKB_DROP_REASON_IPV6DISABLED;
929 goto drop;
930 }
931
932 /* Ignore if IOAM is not enabled on ingress */
933 if (!READ_ONCE(idev->cnf.ioam6_enabled))
934 goto ignore;
935
936 /* Truncated Option header */
937 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
938 if (hdr->opt_len < 2)
939 goto drop;
940
941 switch (hdr->type) {
942 case IOAM6_TYPE_PREALLOC:
943 /* Truncated Pre-allocated Trace header */
944 if (hdr->opt_len < 2 + sizeof(*trace))
945 goto drop;
946
947 /* Malformed Pre-allocated Trace header */
948 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
949 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
950 goto drop;
951
952 /* Inconsistent Pre-allocated Trace header */
953 if (trace->nodelen !=
954 ioam6_trace_compute_nodelen(be32_to_cpu(trace->type_be32)))
955 goto drop;
956
957 /* Ignore if the IOAM namespace is unknown */
958 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id);
959 if (!ns)
960 goto ignore;
961
962 if (!skb_valid_dst(skb))
963 ip6_route_input(skb);
964
965 /* About to mangle packet header */
966 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
967 goto drop;
968
969 /* Trace and hdr pointers may have changed */
970 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
971 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
972
973 ioam6_fill_trace_data(skb, ns, trace, true);
974
975 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev),
976 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2);
977 break;
978 default:
979 break;
980 }
981
982 ignore:
983 return true;
984
985 drop:
986 kfree_skb_reason(skb, drop_reason);
987 return false;
988 }
989
990 /* Jumbo payload */
991
ipv6_hop_jumbo(struct sk_buff * skb,int optoff)992 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
993 {
994 const unsigned char *nh = skb_network_header(skb);
995 SKB_DR(reason);
996 u32 pkt_len;
997
998 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
999 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
1000 nh[optoff+1]);
1001 SKB_DR_SET(reason, IP_INHDR);
1002 goto drop;
1003 }
1004
1005 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
1006 if (pkt_len <= IPV6_MAXPLEN) {
1007 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
1008 SKB_DROP_REASON_IP_INHDR);
1009 return false;
1010 }
1011 if (ipv6_hdr(skb)->payload_len) {
1012 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
1013 SKB_DROP_REASON_IP_INHDR);
1014 return false;
1015 }
1016
1017 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
1018 SKB_DR_SET(reason, PKT_TOO_SMALL);
1019 goto drop;
1020 }
1021
1022 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1023 goto drop;
1024
1025 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1026 return true;
1027
1028 drop:
1029 kfree_skb_reason(skb, reason);
1030 return false;
1031 }
1032
1033 /* CALIPSO RFC 5570 */
1034
ipv6_hop_calipso(struct sk_buff * skb,int optoff)1035 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1036 {
1037 const unsigned char *nh = skb_network_header(skb);
1038
1039 if (nh[optoff + 1] < 8)
1040 goto drop;
1041
1042 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1043 goto drop;
1044
1045 if (!calipso_validate(skb, nh + optoff))
1046 goto drop;
1047
1048 return true;
1049
1050 drop:
1051 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1052 return false;
1053 }
1054
ipv6_parse_hopopts(struct sk_buff * skb)1055 int ipv6_parse_hopopts(struct sk_buff *skb)
1056 {
1057 struct inet6_skb_parm *opt = IP6CB(skb);
1058 struct net *net = dev_net(skb->dev);
1059 int extlen;
1060
1061 /*
1062 * skb_network_header(skb) is equal to skb->data, and
1063 * skb_network_header_len(skb) is always equal to
1064 * sizeof(struct ipv6hdr) by definition of
1065 * hop-by-hop options.
1066 */
1067 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1068 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1069 ((skb_transport_header(skb)[1] + 1) << 3)))) {
1070 fail_and_free:
1071 kfree_skb(skb);
1072 return -1;
1073 }
1074
1075 extlen = (skb_transport_header(skb)[1] + 1) << 3;
1076 if (extlen > READ_ONCE(net->ipv6.sysctl.max_hbh_opts_len))
1077 goto fail_and_free;
1078
1079 opt->flags |= IP6SKB_HOPBYHOP;
1080 if (ip6_parse_tlv(true, skb,
1081 READ_ONCE(net->ipv6.sysctl.max_hbh_opts_cnt))) {
1082 skb->transport_header += extlen;
1083 opt = IP6CB(skb);
1084 opt->nhoff = sizeof(struct ipv6hdr);
1085 return 1;
1086 }
1087 return -1;
1088 }
1089
1090 /*
1091 * Creating outbound headers.
1092 *
1093 * "build" functions work when skb is filled from head to tail (datagram)
1094 * "push" functions work when headers are added from tail to head (tcp)
1095 *
1096 * In both cases we assume, that caller reserved enough room
1097 * for headers.
1098 */
1099
ipv6_push_rthdr0(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1100 static u8 ipv6_push_rthdr0(struct sk_buff *skb, u8 proto,
1101 struct ipv6_rt_hdr *opt,
1102 struct in6_addr **addr_p, struct in6_addr *saddr)
1103 {
1104 struct rt0_hdr *phdr, *ihdr;
1105 int hops;
1106
1107 ihdr = (struct rt0_hdr *) opt;
1108
1109 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1110 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1111
1112 hops = ihdr->rt_hdr.hdrlen >> 1;
1113
1114 if (hops > 1)
1115 memcpy(phdr->addr, ihdr->addr + 1,
1116 (hops - 1) * sizeof(struct in6_addr));
1117
1118 phdr->addr[hops - 1] = **addr_p;
1119 *addr_p = ihdr->addr;
1120
1121 phdr->rt_hdr.nexthdr = proto;
1122 return NEXTHDR_ROUTING;
1123 }
1124
ipv6_push_rthdr4(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1125 static u8 ipv6_push_rthdr4(struct sk_buff *skb, u8 proto,
1126 struct ipv6_rt_hdr *opt,
1127 struct in6_addr **addr_p, struct in6_addr *saddr)
1128 {
1129 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1130 int plen, hops;
1131
1132 sr_ihdr = (struct ipv6_sr_hdr *)opt;
1133 plen = (sr_ihdr->hdrlen + 1) << 3;
1134
1135 sr_phdr = skb_push(skb, plen);
1136 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1137
1138 hops = sr_ihdr->first_segment + 1;
1139 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1140 (hops - 1) * sizeof(struct in6_addr));
1141
1142 sr_phdr->segments[0] = **addr_p;
1143 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1144
1145 if (sr_ihdr->hdrlen > hops * 2) {
1146 int tlvs_offset, tlvs_length;
1147
1148 tlvs_offset = (1 + hops * 2) << 3;
1149 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1150 memcpy((char *)sr_phdr + tlvs_offset,
1151 (char *)sr_ihdr + tlvs_offset, tlvs_length);
1152 }
1153
1154 #ifdef CONFIG_IPV6_SEG6_HMAC
1155 if (sr_has_hmac(sr_phdr)) {
1156 struct net *net = NULL;
1157
1158 if (skb->dev)
1159 net = dev_net(skb->dev);
1160 else if (skb->sk)
1161 net = sock_net(skb->sk);
1162
1163 WARN_ON(!net);
1164
1165 if (net)
1166 seg6_push_hmac(net, saddr, sr_phdr);
1167 }
1168 #endif
1169
1170 sr_phdr->nexthdr = proto;
1171 return NEXTHDR_ROUTING;
1172 }
1173
ipv6_push_rthdr(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1174 static u8 ipv6_push_rthdr(struct sk_buff *skb, u8 proto,
1175 struct ipv6_rt_hdr *opt,
1176 struct in6_addr **addr_p, struct in6_addr *saddr)
1177 {
1178 switch (opt->type) {
1179 case IPV6_SRCRT_TYPE_0:
1180 case IPV6_SRCRT_STRICT:
1181 case IPV6_SRCRT_TYPE_2:
1182 proto = ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1183 break;
1184 case IPV6_SRCRT_TYPE_4:
1185 proto = ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1186 break;
1187 default:
1188 break;
1189 }
1190 return proto;
1191 }
1192
ipv6_push_exthdr(struct sk_buff * skb,u8 proto,u8 type,struct ipv6_opt_hdr * opt)1193 static u8 ipv6_push_exthdr(struct sk_buff *skb, u8 proto, u8 type, struct ipv6_opt_hdr *opt)
1194 {
1195 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1196
1197 memcpy(h, opt, ipv6_optlen(opt));
1198 h->nexthdr = proto;
1199 return type;
1200 }
1201
ipv6_push_nfrag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 proto,struct in6_addr ** daddr,struct in6_addr * saddr)1202 u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1203 u8 proto,
1204 struct in6_addr **daddr, struct in6_addr *saddr)
1205 {
1206 if (opt->srcrt) {
1207 proto = ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1208 /*
1209 * IPV6_RTHDRDSTOPTS is ignored
1210 * unless IPV6_RTHDR is set (RFC3542).
1211 */
1212 if (opt->dst0opt)
1213 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1214 }
1215 if (opt->hopopt)
1216 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1217 return proto;
1218 }
1219
ipv6_push_frag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 proto)1220 u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 proto)
1221 {
1222 if (opt->dst1opt)
1223 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1224 return proto;
1225 }
1226 EXPORT_SYMBOL(ipv6_push_frag_opts);
1227
1228 struct ipv6_txoptions *
ipv6_dup_options(struct sock * sk,struct ipv6_txoptions * opt)1229 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1230 {
1231 struct ipv6_txoptions *opt2;
1232
1233 opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC);
1234 if (opt2) {
1235 long dif = (char *)opt2 - (char *)opt;
1236 if (opt2->hopopt)
1237 *((char **)&opt2->hopopt) += dif;
1238 if (opt2->dst0opt)
1239 *((char **)&opt2->dst0opt) += dif;
1240 if (opt2->dst1opt)
1241 *((char **)&opt2->dst1opt) += dif;
1242 if (opt2->srcrt)
1243 *((char **)&opt2->srcrt) += dif;
1244 refcount_set(&opt2->refcnt, 1);
1245 }
1246 return opt2;
1247 }
1248 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1249
ipv6_renew_option(int renewtype,struct ipv6_opt_hdr ** dest,struct ipv6_opt_hdr * old,struct ipv6_opt_hdr * new,int newtype,char ** p)1250 static void ipv6_renew_option(int renewtype,
1251 struct ipv6_opt_hdr **dest,
1252 struct ipv6_opt_hdr *old,
1253 struct ipv6_opt_hdr *new,
1254 int newtype, char **p)
1255 {
1256 struct ipv6_opt_hdr *src;
1257
1258 src = (renewtype == newtype ? new : old);
1259 if (!src)
1260 return;
1261
1262 memcpy(*p, src, ipv6_optlen(src));
1263 *dest = (struct ipv6_opt_hdr *)*p;
1264 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1265 }
1266
1267 /**
1268 * ipv6_renew_options - replace a specific ext hdr with a new one.
1269 *
1270 * @sk: sock from which to allocate memory
1271 * @opt: original options
1272 * @newtype: option type to replace in @opt
1273 * @newopt: new option of type @newtype to replace (user-mem)
1274 *
1275 * Returns a new set of options which is a copy of @opt with the
1276 * option type @newtype replaced with @newopt.
1277 *
1278 * @opt may be NULL, in which case a new set of options is returned
1279 * containing just @newopt.
1280 *
1281 * @newopt may be NULL, in which case the specified option type is
1282 * not copied into the new set of options.
1283 *
1284 * The new set of options is allocated from the socket option memory
1285 * buffer of @sk.
1286 */
1287 struct ipv6_txoptions *
ipv6_renew_options(struct sock * sk,struct ipv6_txoptions * opt,int newtype,struct ipv6_opt_hdr * newopt)1288 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1289 int newtype, struct ipv6_opt_hdr *newopt)
1290 {
1291 int tot_len = 0;
1292 char *p;
1293 struct ipv6_txoptions *opt2;
1294
1295 if (opt) {
1296 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1297 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1298 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1299 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1300 if (newtype != IPV6_RTHDR && opt->srcrt)
1301 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1302 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1303 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1304 }
1305
1306 if (newopt)
1307 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1308
1309 if (!tot_len)
1310 return NULL;
1311
1312 tot_len += sizeof(*opt2);
1313 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1314 if (!opt2)
1315 return ERR_PTR(-ENOBUFS);
1316
1317 memset(opt2, 0, tot_len);
1318 refcount_set(&opt2->refcnt, 1);
1319 opt2->tot_len = tot_len;
1320 p = (char *)(opt2 + 1);
1321
1322 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1323 (opt ? opt->hopopt : NULL),
1324 newopt, newtype, &p);
1325 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1326 (opt ? opt->dst0opt : NULL),
1327 newopt, newtype, &p);
1328 ipv6_renew_option(IPV6_RTHDR,
1329 (struct ipv6_opt_hdr **)&opt2->srcrt,
1330 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1331 newopt, newtype, &p);
1332 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1333 (opt ? opt->dst1opt : NULL),
1334 newopt, newtype, &p);
1335
1336 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1337 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1338 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1339 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1340
1341 return opt2;
1342 }
1343
__ipv6_fixup_options(struct ipv6_txoptions * opt_space,struct ipv6_txoptions * opt)1344 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1345 struct ipv6_txoptions *opt)
1346 {
1347 /*
1348 * ignore the dest before srcrt unless srcrt is being included.
1349 * --yoshfuji
1350 */
1351 if (opt->dst0opt && !opt->srcrt) {
1352 if (opt_space != opt) {
1353 memcpy(opt_space, opt, sizeof(*opt_space));
1354 opt = opt_space;
1355 }
1356 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1357 opt->dst0opt = NULL;
1358 }
1359
1360 return opt;
1361 }
1362 EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
1363
1364 /**
1365 * __fl6_update_dst - update flowi destination address with info given
1366 * by srcrt option, if any.
1367 *
1368 * @fl6: flowi6 for which daddr is to be updated
1369 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1370 * @orig: copy of original daddr address if modified
1371 *
1372 * Return: NULL if no srcrt or invalid srcrt type, otherwise returns orig
1373 * and initial value of fl6->daddr set in orig
1374 */
__fl6_update_dst(struct flowi6 * fl6,const struct ipv6_txoptions * opt,struct in6_addr * orig)1375 struct in6_addr *__fl6_update_dst(struct flowi6 *fl6,
1376 const struct ipv6_txoptions *opt,
1377 struct in6_addr *orig)
1378 {
1379 if (!opt->srcrt)
1380 return NULL;
1381
1382 *orig = fl6->daddr;
1383
1384 switch (opt->srcrt->type) {
1385 case IPV6_SRCRT_TYPE_0:
1386 case IPV6_SRCRT_STRICT:
1387 case IPV6_SRCRT_TYPE_2:
1388 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1389 break;
1390 case IPV6_SRCRT_TYPE_4:
1391 {
1392 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1393
1394 fl6->daddr = srh->segments[srh->segments_left];
1395 break;
1396 }
1397 default:
1398 return NULL;
1399 }
1400
1401 return orig;
1402 }
1403 EXPORT_SYMBOL_GPL(__fl6_update_dst);
1404