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
188 nh = skb_network_header(skb);
189 break;
190 case IPV6_TLV_CALIPSO:
191 if (!ipv6_hop_calipso(skb, off))
192 return false;
193 break;
194 default:
195 if (!ip6_tlvopt_unknown(skb, off,
196 disallow_unknowns))
197 return false;
198 break;
199 }
200 } else {
201 switch (nh[off]) {
202 #if IS_ENABLED(CONFIG_IPV6_MIP6)
203 case IPV6_TLV_HAO:
204 if (!ipv6_dest_hao(skb, off))
205 return false;
206
207 nh = skb_network_header(skb);
208 break;
209 #endif
210 default:
211 if (!ip6_tlvopt_unknown(skb, off,
212 disallow_unknowns))
213 return false;
214 break;
215 }
216 }
217 padlen = 0;
218 }
219 off += optlen;
220 len -= optlen;
221 }
222
223 if (len == 0)
224 return true;
225 bad:
226 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
227 return false;
228 }
229
230 /*****************************
231 Destination options header.
232 *****************************/
233
234 #if IS_ENABLED(CONFIG_IPV6_MIP6)
ipv6_dest_hao(struct sk_buff * skb,int optoff)235 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
236 {
237 struct ipv6_destopt_hao *hao;
238 struct inet6_skb_parm *opt = IP6CB(skb);
239 struct ipv6hdr *ipv6h = ipv6_hdr(skb);
240 SKB_DR(reason);
241 int ret;
242
243 if (opt->dsthao) {
244 net_dbg_ratelimited("hao duplicated\n");
245 goto discard;
246 }
247 opt->dsthao = opt->dst1;
248 opt->dst1 = 0;
249
250 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
251
252 if (hao->length != 16) {
253 net_dbg_ratelimited("hao invalid option length = %d\n",
254 hao->length);
255 SKB_DR_SET(reason, IP_INHDR);
256 goto discard;
257 }
258
259 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
260 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
261 &hao->addr);
262 SKB_DR_SET(reason, INVALID_PROTO);
263 goto discard;
264 }
265
266 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
267 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
268 if (unlikely(ret < 0)) {
269 SKB_DR_SET(reason, XFRM_POLICY);
270 goto discard;
271 }
272
273 if (skb_cloned(skb)) {
274 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
275 goto discard;
276
277 /* update all variable using below by copied skbuff */
278 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
279 optoff);
280 ipv6h = ipv6_hdr(skb);
281 }
282
283 if (skb->ip_summed == CHECKSUM_COMPLETE)
284 skb->ip_summed = CHECKSUM_NONE;
285
286 swap(ipv6h->saddr, hao->addr);
287
288 if (skb->tstamp == 0)
289 __net_timestamp(skb);
290
291 return true;
292
293 discard:
294 kfree_skb_reason(skb, reason);
295 return false;
296 }
297 #endif
298
ipv6_destopt_rcv(struct sk_buff * skb)299 static int ipv6_destopt_rcv(struct sk_buff *skb)
300 {
301 struct inet6_dev *idev = __in6_dev_get(skb->dev);
302 struct inet6_skb_parm *opt = IP6CB(skb);
303 #if IS_ENABLED(CONFIG_IPV6_MIP6)
304 __u16 dstbuf;
305 #endif
306 struct dst_entry *dst = skb_dst(skb);
307 struct net *net = dev_net(skb->dev);
308 int extlen;
309
310 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
311 !pskb_may_pull(skb, (skb_transport_offset(skb) +
312 ((skb_transport_header(skb)[1] + 1) << 3)))) {
313 __IP6_INC_STATS(dev_net(dst_dev(dst)), idev,
314 IPSTATS_MIB_INHDRERRORS);
315 fail_and_free:
316 kfree_skb(skb);
317 return -1;
318 }
319
320 extlen = (skb_transport_header(skb)[1] + 1) << 3;
321 if (extlen > READ_ONCE(net->ipv6.sysctl.max_dst_opts_len))
322 goto fail_and_free;
323
324 opt->lastopt = opt->dst1 = skb_network_header_len(skb);
325 #if IS_ENABLED(CONFIG_IPV6_MIP6)
326 dstbuf = opt->dst1;
327 #endif
328
329 if (ip6_parse_tlv(false, skb,
330 READ_ONCE(net->ipv6.sysctl.max_dst_opts_cnt))) {
331 skb->transport_header += extlen;
332 opt = IP6CB(skb);
333 #if IS_ENABLED(CONFIG_IPV6_MIP6)
334 opt->nhoff = dstbuf;
335 #else
336 opt->nhoff = opt->dst1;
337 #endif
338 return 1;
339 }
340
341 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
342 return -1;
343 }
344
seg6_update_csum(struct sk_buff * skb)345 static void seg6_update_csum(struct sk_buff *skb)
346 {
347 struct ipv6_sr_hdr *hdr;
348 struct in6_addr *addr;
349 __be32 from, to;
350
351 /* srh is at transport offset and seg_left is already decremented
352 * but daddr is not yet updated with next segment
353 */
354
355 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
356 addr = hdr->segments + hdr->segments_left;
357
358 hdr->segments_left++;
359 from = *(__be32 *)hdr;
360
361 hdr->segments_left--;
362 to = *(__be32 *)hdr;
363
364 /* update skb csum with diff resulting from seg_left decrement */
365
366 update_csum_diff4(skb, from, to);
367
368 /* compute csum diff between current and next segment and update */
369
370 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
371 (__be32 *)addr);
372 }
373
ipv6_srh_rcv(struct sk_buff * skb)374 static int ipv6_srh_rcv(struct sk_buff *skb)
375 {
376 struct inet6_skb_parm *opt = IP6CB(skb);
377 struct net *net = dev_net(skb->dev);
378 struct ipv6_sr_hdr *hdr;
379 struct inet6_dev *idev;
380 struct in6_addr *addr;
381 int accept_seg6;
382
383 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
384
385 idev = __in6_dev_get(skb->dev);
386 if (!idev) {
387 kfree_skb(skb);
388 return -1;
389 }
390
391 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled),
392 READ_ONCE(idev->cnf.seg6_enabled));
393
394 if (!accept_seg6) {
395 kfree_skb(skb);
396 return -1;
397 }
398
399 #ifdef CONFIG_IPV6_SEG6_HMAC
400 if (!seg6_hmac_validate_skb(skb)) {
401 kfree_skb(skb);
402 return -1;
403 }
404 #endif
405
406 looped_back:
407 if (hdr->segments_left == 0) {
408 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
409 int offset = (hdr->hdrlen + 1) << 3;
410
411 skb_postpull_rcsum(skb, skb_network_header(skb),
412 skb_network_header_len(skb));
413 skb_pull(skb, offset);
414 skb_postpull_rcsum(skb, skb_transport_header(skb),
415 offset);
416
417 skb_reset_network_header(skb);
418 skb_reset_transport_header(skb);
419 skb->encapsulation = 0;
420 if (hdr->nexthdr == NEXTHDR_IPV4)
421 skb->protocol = htons(ETH_P_IP);
422 __skb_tunnel_rx(skb, skb->dev, net);
423
424 netif_rx(skb);
425 return -1;
426 }
427
428 opt->srcrt = skb_network_header_len(skb);
429 opt->lastopt = opt->srcrt;
430 skb->transport_header += (hdr->hdrlen + 1) << 3;
431 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
432
433 return 1;
434 }
435
436 if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
437 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
438 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
439 ((&hdr->segments_left) -
440 skb_network_header(skb)));
441 return -1;
442 }
443
444 if (skb_cloned(skb)) {
445 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
446 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
447 IPSTATS_MIB_OUTDISCARDS);
448 kfree_skb(skb);
449 return -1;
450 }
451
452 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
453 }
454
455 hdr->segments_left--;
456 addr = hdr->segments + hdr->segments_left;
457
458 skb_push(skb, sizeof(struct ipv6hdr));
459
460 if (skb->ip_summed == CHECKSUM_COMPLETE)
461 seg6_update_csum(skb);
462
463 ipv6_hdr(skb)->daddr = *addr;
464
465 ip6_route_input(skb);
466
467 if (skb_dst(skb)->error) {
468 dst_input(skb);
469 return -1;
470 }
471
472 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
473 if (ipv6_hdr(skb)->hop_limit <= 1) {
474 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
475 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
476 ICMPV6_EXC_HOPLIMIT, 0);
477 kfree_skb(skb);
478 return -1;
479 }
480 ipv6_hdr(skb)->hop_limit--;
481
482 skb_pull(skb, sizeof(struct ipv6hdr));
483 goto looped_back;
484 }
485
486 dst_input(skb);
487
488 return -1;
489 }
490
ipv6_rpl_srh_rcv(struct sk_buff * skb)491 static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
492 {
493 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
494 struct inet6_skb_parm *opt = IP6CB(skb);
495 struct net *net = dev_net(skb->dev);
496 struct inet6_dev *idev;
497 struct ipv6hdr *oldhdr;
498 unsigned int chdr_len;
499 unsigned char *buf;
500 int accept_rpl_seg;
501 int i, err;
502 u64 n = 0;
503 u32 r;
504
505 idev = __in6_dev_get(skb->dev);
506
507 accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled),
508 READ_ONCE(idev->cnf.rpl_seg_enabled));
509 if (!accept_rpl_seg) {
510 kfree_skb(skb);
511 return -1;
512 }
513
514 looped_back:
515 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
516
517 if (hdr->segments_left == 0) {
518 if (hdr->nexthdr == NEXTHDR_IPV6) {
519 int offset = (hdr->hdrlen + 1) << 3;
520
521 skb_postpull_rcsum(skb, skb_network_header(skb),
522 skb_network_header_len(skb));
523 skb_pull(skb, offset);
524 skb_postpull_rcsum(skb, skb_transport_header(skb),
525 offset);
526
527 skb_reset_network_header(skb);
528 skb_reset_transport_header(skb);
529 skb->encapsulation = 0;
530
531 __skb_tunnel_rx(skb, skb->dev, net);
532
533 netif_rx(skb);
534 return -1;
535 }
536
537 opt->srcrt = skb_network_header_len(skb);
538 opt->lastopt = opt->srcrt;
539 skb->transport_header += (hdr->hdrlen + 1) << 3;
540 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
541
542 return 1;
543 }
544
545 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
546 r = do_div(n, (16 - hdr->cmpri));
547 /* checks if calculation was without remainder and n fits into
548 * unsigned char which is segments_left field. Should not be
549 * higher than that.
550 */
551 if (r || (n + 1) > 127) {
552 kfree_skb(skb);
553 return -1;
554 }
555
556 if (hdr->segments_left > n + 1) {
557 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
558 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
559 ((&hdr->segments_left) -
560 skb_network_header(skb)));
561 return -1;
562 }
563
564 hdr->segments_left--;
565 i = n - hdr->segments_left;
566
567 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
568 if (unlikely(!buf)) {
569 kfree_skb(skb);
570 return -1;
571 }
572
573 ohdr = (struct ipv6_rpl_sr_hdr *)buf;
574 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
575 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
576
577 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
578 kfree_skb(skb);
579 kfree(buf);
580 return -1;
581 }
582
583 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
584 if (err) {
585 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
586 kfree_skb(skb);
587 kfree(buf);
588 return -1;
589 }
590
591 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
592
593 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
594
595 oldhdr = ipv6_hdr(skb);
596
597 skb_pull(skb, ((hdr->hdrlen + 1) << 3));
598 skb_postpull_rcsum(skb, oldhdr,
599 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
600 chdr_len = sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3);
601 if (unlikely(!hdr->segments_left ||
602 skb_headroom(skb) < chdr_len + skb->mac_len)) {
603 if (pskb_expand_head(skb, chdr_len + skb->mac_len, 0,
604 GFP_ATOMIC)) {
605 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
606 kfree_skb(skb);
607 kfree(buf);
608 return -1;
609 }
610
611 oldhdr = ipv6_hdr(skb);
612 }
613 skb_push(skb, chdr_len);
614 skb_reset_network_header(skb);
615 skb_mac_header_rebuild(skb);
616 skb_set_transport_header(skb, sizeof(struct ipv6hdr));
617
618 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
619 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
620
621 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
622 skb_postpush_rcsum(skb, ipv6_hdr(skb),
623 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
624
625 kfree(buf);
626
627 ip6_route_input(skb);
628
629 if (skb_dst(skb)->error) {
630 dst_input(skb);
631 return -1;
632 }
633
634 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
635 if (ipv6_hdr(skb)->hop_limit <= 1) {
636 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
637 icmpv6_send(skb, ICMPV6_TIME_EXCEED,
638 ICMPV6_EXC_HOPLIMIT, 0);
639 kfree_skb(skb);
640 return -1;
641 }
642 ipv6_hdr(skb)->hop_limit--;
643
644 skb_pull(skb, sizeof(struct ipv6hdr));
645 goto looped_back;
646 }
647
648 dst_input(skb);
649
650 return -1;
651 }
652
653 /********************************
654 Routing header.
655 ********************************/
656
657 /* called with rcu_read_lock() */
ipv6_rthdr_rcv(struct sk_buff * skb)658 static int ipv6_rthdr_rcv(struct sk_buff *skb)
659 {
660 struct inet6_dev *idev = __in6_dev_get(skb->dev);
661 struct inet6_skb_parm *opt = IP6CB(skb);
662 struct in6_addr *addr = NULL;
663 int n, i;
664 struct ipv6_rt_hdr *hdr;
665 struct rt0_hdr *rthdr;
666 struct net *net = dev_net(skb->dev);
667 int accept_source_route;
668
669 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route);
670
671 if (idev)
672 accept_source_route = min(accept_source_route,
673 READ_ONCE(idev->cnf.accept_source_route));
674
675 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
676 !pskb_may_pull(skb, (skb_transport_offset(skb) +
677 ((skb_transport_header(skb)[1] + 1) << 3)))) {
678 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
679 kfree_skb(skb);
680 return -1;
681 }
682
683 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
684
685 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
686 skb->pkt_type != PACKET_HOST) {
687 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
688 kfree_skb(skb);
689 return -1;
690 }
691
692 switch (hdr->type) {
693 case IPV6_SRCRT_TYPE_4:
694 /* segment routing */
695 return ipv6_srh_rcv(skb);
696 case IPV6_SRCRT_TYPE_3:
697 /* rpl segment routing */
698 return ipv6_rpl_srh_rcv(skb);
699 default:
700 break;
701 }
702
703 looped_back:
704 if (hdr->segments_left == 0) {
705 switch (hdr->type) {
706 #if IS_ENABLED(CONFIG_IPV6_MIP6)
707 case IPV6_SRCRT_TYPE_2:
708 /* Silently discard type 2 header unless it was
709 * processed by own
710 */
711 if (!addr) {
712 __IP6_INC_STATS(net, idev,
713 IPSTATS_MIB_INADDRERRORS);
714 kfree_skb(skb);
715 return -1;
716 }
717 break;
718 #endif
719 default:
720 break;
721 }
722
723 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
724 skb->transport_header += (hdr->hdrlen + 1) << 3;
725 opt->dst0 = opt->dst1;
726 opt->dst1 = 0;
727 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
728 return 1;
729 }
730
731 switch (hdr->type) {
732 #if IS_ENABLED(CONFIG_IPV6_MIP6)
733 case IPV6_SRCRT_TYPE_2:
734 if (accept_source_route < 0)
735 goto unknown_rh;
736 /* Silently discard invalid RTH type 2 */
737 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
738 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
739 kfree_skb(skb);
740 return -1;
741 }
742 break;
743 #endif
744 default:
745 goto unknown_rh;
746 }
747
748 /*
749 * This is the routing header forwarding algorithm from
750 * RFC 2460, page 16.
751 */
752
753 n = hdr->hdrlen >> 1;
754
755 if (hdr->segments_left > n) {
756 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
757 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
758 ((&hdr->segments_left) -
759 skb_network_header(skb)));
760 return -1;
761 }
762
763 /* We are about to mangle packet header. Be careful!
764 Do not damage packets queued somewhere.
765 */
766 if (skb_cloned(skb)) {
767 /* the copy is a forwarded packet */
768 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
769 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
770 IPSTATS_MIB_OUTDISCARDS);
771 kfree_skb(skb);
772 return -1;
773 }
774 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
775 }
776
777 if (skb->ip_summed == CHECKSUM_COMPLETE)
778 skb->ip_summed = CHECKSUM_NONE;
779
780 i = n - --hdr->segments_left;
781
782 rthdr = (struct rt0_hdr *) hdr;
783 addr = rthdr->addr;
784 addr += i - 1;
785
786 switch (hdr->type) {
787 #if IS_ENABLED(CONFIG_IPV6_MIP6)
788 case IPV6_SRCRT_TYPE_2:
789 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
790 (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
791 IPPROTO_ROUTING) < 0) {
792 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
793 kfree_skb(skb);
794 return -1;
795 }
796 if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) {
797 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
798 kfree_skb(skb);
799 return -1;
800 }
801 break;
802 #endif
803 default:
804 break;
805 }
806
807 if (ipv6_addr_is_multicast(addr)) {
808 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
809 kfree_skb(skb);
810 return -1;
811 }
812
813 swap(*addr, ipv6_hdr(skb)->daddr);
814
815 ip6_route_input(skb);
816 if (skb_dst(skb)->error) {
817 skb_push(skb, -skb_network_offset(skb));
818 dst_input(skb);
819 return -1;
820 }
821
822 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
823 if (ipv6_hdr(skb)->hop_limit <= 1) {
824 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
825 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
826 0);
827 kfree_skb(skb);
828 return -1;
829 }
830 ipv6_hdr(skb)->hop_limit--;
831 goto looped_back;
832 }
833
834 skb_push(skb, -skb_network_offset(skb));
835 dst_input(skb);
836 return -1;
837
838 unknown_rh:
839 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
840 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
841 (&hdr->type) - skb_network_header(skb));
842 return -1;
843 }
844
845 static const struct inet6_protocol rthdr_protocol = {
846 .handler = ipv6_rthdr_rcv,
847 .flags = INET6_PROTO_NOPOLICY,
848 };
849
850 static const struct inet6_protocol destopt_protocol = {
851 .handler = ipv6_destopt_rcv,
852 .flags = INET6_PROTO_NOPOLICY,
853 };
854
855 static const struct inet6_protocol nodata_protocol = {
856 .handler = dst_discard,
857 .flags = INET6_PROTO_NOPOLICY,
858 };
859
ipv6_exthdrs_init(void)860 int __init ipv6_exthdrs_init(void)
861 {
862 int ret;
863
864 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
865 if (ret)
866 goto out;
867
868 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
869 if (ret)
870 goto out_rthdr;
871
872 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
873 if (ret)
874 goto out_destopt;
875
876 out:
877 return ret;
878 out_destopt:
879 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
880 out_rthdr:
881 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
882 goto out;
883 };
884
ipv6_exthdrs_exit(void)885 void ipv6_exthdrs_exit(void)
886 {
887 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
888 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
889 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
890 }
891
892 /**********************************
893 Hop-by-hop options.
894 **********************************/
895
896 /* Router Alert as of RFC 2711 */
897
ipv6_hop_ra(struct sk_buff * skb,int optoff)898 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
899 {
900 const unsigned char *nh = skb_network_header(skb);
901
902 if (nh[optoff + 1] == 2) {
903 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
904 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
905 return true;
906 }
907 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
908 nh[optoff + 1]);
909 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
910 return false;
911 }
912
913 /* IOAM */
914
ipv6_hop_ioam(struct sk_buff * skb,int optoff)915 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
916 {
917 enum skb_drop_reason drop_reason;
918 struct ioam6_trace_hdr *trace;
919 struct ioam6_namespace *ns;
920 struct inet6_dev *idev;
921 struct ioam6_hdr *hdr;
922
923 drop_reason = SKB_DROP_REASON_IP_INHDR;
924
925 /* Bad alignment (must be 4n-aligned) */
926 if (optoff & 3)
927 goto drop;
928
929 /* Does the device still have IPv6 configuration? */
930 idev = __in6_dev_get(skb->dev);
931 if (!idev) {
932 drop_reason = SKB_DROP_REASON_IPV6DISABLED;
933 goto drop;
934 }
935
936 /* Ignore if IOAM is not enabled on ingress */
937 if (!READ_ONCE(idev->cnf.ioam6_enabled))
938 goto ignore;
939
940 /* Truncated Option header */
941 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
942 if (hdr->opt_len < 2)
943 goto drop;
944
945 switch (hdr->type) {
946 case IOAM6_TYPE_PREALLOC:
947 /* Truncated Pre-allocated Trace header */
948 if (hdr->opt_len < 2 + sizeof(*trace))
949 goto drop;
950
951 /* Malformed Pre-allocated Trace header */
952 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
953 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
954 goto drop;
955
956 /* Inconsistent Pre-allocated Trace header */
957 if (trace->nodelen !=
958 ioam6_trace_compute_nodelen(be32_to_cpu(trace->type_be32)))
959 goto drop;
960
961 /* Ignore if the IOAM namespace is unknown */
962 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id);
963 if (!ns)
964 goto ignore;
965
966 if (!skb_valid_dst(skb))
967 ip6_route_input(skb);
968
969 /* About to mangle packet header */
970 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
971 goto drop;
972
973 /* Trace and hdr pointers may have changed */
974 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
975 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
976
977 ioam6_fill_trace_data(skb, ns, trace, true);
978
979 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev),
980 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2);
981 break;
982 default:
983 break;
984 }
985
986 ignore:
987 return true;
988
989 drop:
990 kfree_skb_reason(skb, drop_reason);
991 return false;
992 }
993
994 /* Jumbo payload */
995
ipv6_hop_jumbo(struct sk_buff * skb,int optoff)996 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
997 {
998 const unsigned char *nh = skb_network_header(skb);
999 SKB_DR(reason);
1000 u32 pkt_len;
1001
1002 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
1003 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
1004 nh[optoff+1]);
1005 SKB_DR_SET(reason, IP_INHDR);
1006 goto drop;
1007 }
1008
1009 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
1010 if (pkt_len <= IPV6_MAXPLEN) {
1011 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
1012 SKB_DROP_REASON_IP_INHDR);
1013 return false;
1014 }
1015 if (ipv6_hdr(skb)->payload_len) {
1016 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
1017 SKB_DROP_REASON_IP_INHDR);
1018 return false;
1019 }
1020
1021 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
1022 SKB_DR_SET(reason, PKT_TOO_SMALL);
1023 goto drop;
1024 }
1025
1026 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1027 goto drop;
1028
1029 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1030 return true;
1031
1032 drop:
1033 kfree_skb_reason(skb, reason);
1034 return false;
1035 }
1036
1037 /* CALIPSO RFC 5570 */
1038
ipv6_hop_calipso(struct sk_buff * skb,int optoff)1039 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1040 {
1041 const unsigned char *nh = skb_network_header(skb);
1042
1043 if (nh[optoff + 1] < 8)
1044 goto drop;
1045
1046 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1047 goto drop;
1048
1049 if (!calipso_validate(skb, nh + optoff))
1050 goto drop;
1051
1052 return true;
1053
1054 drop:
1055 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1056 return false;
1057 }
1058
ipv6_parse_hopopts(struct sk_buff * skb)1059 int ipv6_parse_hopopts(struct sk_buff *skb)
1060 {
1061 struct inet6_skb_parm *opt = IP6CB(skb);
1062 struct net *net = dev_net(skb->dev);
1063 int extlen;
1064
1065 /*
1066 * skb_network_header(skb) is equal to skb->data, and
1067 * skb_network_header_len(skb) is always equal to
1068 * sizeof(struct ipv6hdr) by definition of
1069 * hop-by-hop options.
1070 */
1071 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1072 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1073 ((skb_transport_header(skb)[1] + 1) << 3)))) {
1074 fail_and_free:
1075 kfree_skb(skb);
1076 return -1;
1077 }
1078
1079 extlen = (skb_transport_header(skb)[1] + 1) << 3;
1080 if (extlen > READ_ONCE(net->ipv6.sysctl.max_hbh_opts_len))
1081 goto fail_and_free;
1082
1083 opt->flags |= IP6SKB_HOPBYHOP;
1084 if (ip6_parse_tlv(true, skb,
1085 READ_ONCE(net->ipv6.sysctl.max_hbh_opts_cnt))) {
1086 skb->transport_header += extlen;
1087 opt = IP6CB(skb);
1088 opt->nhoff = sizeof(struct ipv6hdr);
1089 return 1;
1090 }
1091 return -1;
1092 }
1093
1094 /*
1095 * Creating outbound headers.
1096 *
1097 * "build" functions work when skb is filled from head to tail (datagram)
1098 * "push" functions work when headers are added from tail to head (tcp)
1099 *
1100 * In both cases we assume, that caller reserved enough room
1101 * for headers.
1102 */
1103
ipv6_push_rthdr0(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1104 static u8 ipv6_push_rthdr0(struct sk_buff *skb, u8 proto,
1105 struct ipv6_rt_hdr *opt,
1106 struct in6_addr **addr_p, struct in6_addr *saddr)
1107 {
1108 struct rt0_hdr *phdr, *ihdr;
1109 int hops;
1110
1111 ihdr = (struct rt0_hdr *) opt;
1112
1113 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1114 memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1115
1116 hops = ihdr->rt_hdr.hdrlen >> 1;
1117
1118 if (hops > 1)
1119 memcpy(phdr->addr, ihdr->addr + 1,
1120 (hops - 1) * sizeof(struct in6_addr));
1121
1122 phdr->addr[hops - 1] = **addr_p;
1123 *addr_p = ihdr->addr;
1124
1125 phdr->rt_hdr.nexthdr = proto;
1126 return NEXTHDR_ROUTING;
1127 }
1128
ipv6_push_rthdr4(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1129 static u8 ipv6_push_rthdr4(struct sk_buff *skb, u8 proto,
1130 struct ipv6_rt_hdr *opt,
1131 struct in6_addr **addr_p, struct in6_addr *saddr)
1132 {
1133 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1134 int plen, hops;
1135
1136 sr_ihdr = (struct ipv6_sr_hdr *)opt;
1137 plen = (sr_ihdr->hdrlen + 1) << 3;
1138
1139 sr_phdr = skb_push(skb, plen);
1140 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1141
1142 hops = sr_ihdr->first_segment + 1;
1143 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1144 (hops - 1) * sizeof(struct in6_addr));
1145
1146 sr_phdr->segments[0] = **addr_p;
1147 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1148
1149 if (sr_ihdr->hdrlen > hops * 2) {
1150 int tlvs_offset, tlvs_length;
1151
1152 tlvs_offset = (1 + hops * 2) << 3;
1153 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1154 memcpy((char *)sr_phdr + tlvs_offset,
1155 (char *)sr_ihdr + tlvs_offset, tlvs_length);
1156 }
1157
1158 #ifdef CONFIG_IPV6_SEG6_HMAC
1159 if (sr_has_hmac(sr_phdr)) {
1160 struct net *net = NULL;
1161
1162 if (skb->dev)
1163 net = dev_net(skb->dev);
1164 else if (skb->sk)
1165 net = sock_net(skb->sk);
1166
1167 WARN_ON(!net);
1168
1169 if (net)
1170 seg6_push_hmac(net, saddr, sr_phdr);
1171 }
1172 #endif
1173
1174 sr_phdr->nexthdr = proto;
1175 return NEXTHDR_ROUTING;
1176 }
1177
ipv6_push_rthdr(struct sk_buff * skb,u8 proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1178 static u8 ipv6_push_rthdr(struct sk_buff *skb, u8 proto,
1179 struct ipv6_rt_hdr *opt,
1180 struct in6_addr **addr_p, struct in6_addr *saddr)
1181 {
1182 switch (opt->type) {
1183 case IPV6_SRCRT_TYPE_0:
1184 case IPV6_SRCRT_STRICT:
1185 case IPV6_SRCRT_TYPE_2:
1186 proto = ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1187 break;
1188 case IPV6_SRCRT_TYPE_4:
1189 proto = ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1190 break;
1191 default:
1192 break;
1193 }
1194 return proto;
1195 }
1196
ipv6_push_exthdr(struct sk_buff * skb,u8 proto,u8 type,struct ipv6_opt_hdr * opt)1197 static u8 ipv6_push_exthdr(struct sk_buff *skb, u8 proto, u8 type, struct ipv6_opt_hdr *opt)
1198 {
1199 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1200
1201 memcpy(h, opt, ipv6_optlen(opt));
1202 h->nexthdr = proto;
1203 return type;
1204 }
1205
ipv6_push_nfrag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 proto,struct in6_addr ** daddr,struct in6_addr * saddr)1206 u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1207 u8 proto,
1208 struct in6_addr **daddr, struct in6_addr *saddr)
1209 {
1210 if (opt->srcrt) {
1211 proto = ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1212 /*
1213 * IPV6_RTHDRDSTOPTS is ignored
1214 * unless IPV6_RTHDR is set (RFC3542).
1215 */
1216 if (opt->dst0opt)
1217 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1218 }
1219 if (opt->hopopt)
1220 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1221 return proto;
1222 }
1223
ipv6_push_frag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 proto)1224 u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 proto)
1225 {
1226 if (opt->dst1opt)
1227 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1228 return proto;
1229 }
1230 EXPORT_SYMBOL(ipv6_push_frag_opts);
1231
1232 struct ipv6_txoptions *
ipv6_dup_options(struct sock * sk,struct ipv6_txoptions * opt)1233 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1234 {
1235 struct ipv6_txoptions *opt2;
1236
1237 opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC);
1238 if (opt2) {
1239 long dif = (char *)opt2 - (char *)opt;
1240 if (opt2->hopopt)
1241 *((char **)&opt2->hopopt) += dif;
1242 if (opt2->dst0opt)
1243 *((char **)&opt2->dst0opt) += dif;
1244 if (opt2->dst1opt)
1245 *((char **)&opt2->dst1opt) += dif;
1246 if (opt2->srcrt)
1247 *((char **)&opt2->srcrt) += dif;
1248 refcount_set(&opt2->refcnt, 1);
1249 }
1250 return opt2;
1251 }
1252 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1253
ipv6_renew_option(int renewtype,struct ipv6_opt_hdr ** dest,struct ipv6_opt_hdr * old,struct ipv6_opt_hdr * new,int newtype,char ** p)1254 static void ipv6_renew_option(int renewtype,
1255 struct ipv6_opt_hdr **dest,
1256 struct ipv6_opt_hdr *old,
1257 struct ipv6_opt_hdr *new,
1258 int newtype, char **p)
1259 {
1260 struct ipv6_opt_hdr *src;
1261
1262 src = (renewtype == newtype ? new : old);
1263 if (!src)
1264 return;
1265
1266 memcpy(*p, src, ipv6_optlen(src));
1267 *dest = (struct ipv6_opt_hdr *)*p;
1268 *p += CMSG_ALIGN(ipv6_optlen(*dest));
1269 }
1270
1271 /**
1272 * ipv6_renew_options - replace a specific ext hdr with a new one.
1273 *
1274 * @sk: sock from which to allocate memory
1275 * @opt: original options
1276 * @newtype: option type to replace in @opt
1277 * @newopt: new option of type @newtype to replace (user-mem)
1278 *
1279 * Returns a new set of options which is a copy of @opt with the
1280 * option type @newtype replaced with @newopt.
1281 *
1282 * @opt may be NULL, in which case a new set of options is returned
1283 * containing just @newopt.
1284 *
1285 * @newopt may be NULL, in which case the specified option type is
1286 * not copied into the new set of options.
1287 *
1288 * The new set of options is allocated from the socket option memory
1289 * buffer of @sk.
1290 */
1291 struct ipv6_txoptions *
ipv6_renew_options(struct sock * sk,struct ipv6_txoptions * opt,int newtype,struct ipv6_opt_hdr * newopt)1292 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1293 int newtype, struct ipv6_opt_hdr *newopt)
1294 {
1295 int tot_len = 0;
1296 char *p;
1297 struct ipv6_txoptions *opt2;
1298
1299 if (opt) {
1300 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1301 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1302 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1303 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1304 if (newtype != IPV6_RTHDR && opt->srcrt)
1305 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1306 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1307 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1308 }
1309
1310 if (newopt)
1311 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1312
1313 if (!tot_len)
1314 return NULL;
1315
1316 tot_len += sizeof(*opt2);
1317 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1318 if (!opt2)
1319 return ERR_PTR(-ENOBUFS);
1320
1321 memset(opt2, 0, tot_len);
1322 refcount_set(&opt2->refcnt, 1);
1323 opt2->tot_len = tot_len;
1324 p = (char *)(opt2 + 1);
1325
1326 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1327 (opt ? opt->hopopt : NULL),
1328 newopt, newtype, &p);
1329 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1330 (opt ? opt->dst0opt : NULL),
1331 newopt, newtype, &p);
1332 ipv6_renew_option(IPV6_RTHDR,
1333 (struct ipv6_opt_hdr **)&opt2->srcrt,
1334 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1335 newopt, newtype, &p);
1336 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1337 (opt ? opt->dst1opt : NULL),
1338 newopt, newtype, &p);
1339
1340 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1341 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1342 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1343 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1344
1345 return opt2;
1346 }
1347
__ipv6_fixup_options(struct ipv6_txoptions * opt_space,struct ipv6_txoptions * opt)1348 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1349 struct ipv6_txoptions *opt)
1350 {
1351 /*
1352 * ignore the dest before srcrt unless srcrt is being included.
1353 * --yoshfuji
1354 */
1355 if (opt->dst0opt && !opt->srcrt) {
1356 if (opt_space != opt) {
1357 memcpy(opt_space, opt, sizeof(*opt_space));
1358 opt = opt_space;
1359 }
1360 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1361 opt->dst0opt = NULL;
1362 }
1363
1364 return opt;
1365 }
1366 EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
1367
1368 /**
1369 * __fl6_update_dst - update flowi destination address with info given
1370 * by srcrt option, if any.
1371 *
1372 * @fl6: flowi6 for which daddr is to be updated
1373 * @opt: struct ipv6_txoptions in which to look for srcrt opt
1374 * @orig: copy of original daddr address if modified
1375 *
1376 * Return: NULL if no srcrt or invalid srcrt type, otherwise returns orig
1377 * and initial value of fl6->daddr set in orig
1378 */
__fl6_update_dst(struct flowi6 * fl6,const struct ipv6_txoptions * opt,struct in6_addr * orig)1379 struct in6_addr *__fl6_update_dst(struct flowi6 *fl6,
1380 const struct ipv6_txoptions *opt,
1381 struct in6_addr *orig)
1382 {
1383 if (!opt->srcrt)
1384 return NULL;
1385
1386 *orig = fl6->daddr;
1387
1388 switch (opt->srcrt->type) {
1389 case IPV6_SRCRT_TYPE_0:
1390 case IPV6_SRCRT_STRICT:
1391 case IPV6_SRCRT_TYPE_2:
1392 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1393 break;
1394 case IPV6_SRCRT_TYPE_4:
1395 {
1396 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1397
1398 fl6->daddr = srh->segments[srh->segments_left];
1399 break;
1400 }
1401 default:
1402 return NULL;
1403 }
1404
1405 return orig;
1406 }
1407 EXPORT_SYMBOL_GPL(__fl6_update_dst);
1408