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 <net/ioam6.h>
54 #include <net/dst_metadata.h>
55 
56 #include <linux/uaccess.h>
57 
58 /*********************
59   Generic functions
60  *********************/
61 
62 /* An unknown option is detected, decide what to do */
63 
ip6_tlvopt_unknown(struct sk_buff * skb,int optoff,bool disallow_unknowns)64 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
65 			       bool disallow_unknowns)
66 {
67 	if (disallow_unknowns) {
68 		/* If unknown TLVs are disallowed by configuration
69 		 * then always silently drop packet. Note this also
70 		 * means no ICMP parameter problem is sent which
71 		 * could be a good property to mitigate a reflection DOS
72 		 * attack.
73 		 */
74 
75 		goto drop;
76 	}
77 
78 	switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
79 	case 0: /* ignore */
80 		return true;
81 
82 	case 1: /* drop packet */
83 		break;
84 
85 	case 3: /* Send ICMP if not a multicast address and drop packet */
86 		/* Actually, it is redundant check. icmp_send
87 		   will recheck in any case.
88 		 */
89 		if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
90 			break;
91 		fallthrough;
92 	case 2: /* send ICMP PARM PROB regardless and drop packet */
93 		icmpv6_param_prob_reason(skb, ICMPV6_UNK_OPTION, optoff,
94 					 SKB_DROP_REASON_UNHANDLED_PROTO);
95 		return false;
96 	}
97 
98 drop:
99 	kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO);
100 	return false;
101 }
102 
103 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
104 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
105 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
106 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
107 #if IS_ENABLED(CONFIG_IPV6_MIP6)
108 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff);
109 #endif
110 
111 /* Parse tlv encoded option header (hop-by-hop or destination) */
112 
ip6_parse_tlv(bool hopbyhop,struct sk_buff * skb,int max_count)113 static bool ip6_parse_tlv(bool hopbyhop,
114 			  struct sk_buff *skb,
115 			  int max_count)
116 {
117 	int len = (skb_transport_header(skb)[1] + 1) << 3;
118 	const unsigned char *nh = skb_network_header(skb);
119 	int off = skb_network_header_len(skb);
120 	bool disallow_unknowns = false;
121 	int tlv_count = 0;
122 	int padlen = 0;
123 
124 	if (unlikely(max_count < 0)) {
125 		disallow_unknowns = true;
126 		max_count = -max_count;
127 	}
128 
129 	off += 2;
130 	len -= 2;
131 
132 	while (len > 0) {
133 		int optlen, i;
134 
135 		if (nh[off] == IPV6_TLV_PAD1) {
136 			padlen++;
137 			if (padlen > 7)
138 				goto bad;
139 			off++;
140 			len--;
141 			continue;
142 		}
143 		if (len < 2)
144 			goto bad;
145 		optlen = nh[off + 1] + 2;
146 		if (optlen > len)
147 			goto bad;
148 
149 		if (nh[off] == IPV6_TLV_PADN) {
150 			/* RFC 2460 states that the purpose of PadN is
151 			 * to align the containing header to multiples
152 			 * of 8. 7 is therefore the highest valid value.
153 			 * See also RFC 4942, Section 2.1.9.5.
154 			 */
155 			padlen += optlen;
156 			if (padlen > 7)
157 				goto bad;
158 			/* RFC 4942 recommends receiving hosts to
159 			 * actively check PadN payload to contain
160 			 * only zeroes.
161 			 */
162 			for (i = 2; i < optlen; i++) {
163 				if (nh[off + i] != 0)
164 					goto bad;
165 			}
166 		} else {
167 			tlv_count++;
168 			if (tlv_count > max_count)
169 				goto bad;
170 
171 			if (hopbyhop) {
172 				switch (nh[off]) {
173 				case IPV6_TLV_ROUTERALERT:
174 					if (!ipv6_hop_ra(skb, off))
175 						return false;
176 					break;
177 				case IPV6_TLV_IOAM:
178 					if (!ipv6_hop_ioam(skb, off))
179 						return false;
180 
181 					nh = skb_network_header(skb);
182 					break;
183 				case IPV6_TLV_JUMBO:
184 					if (!ipv6_hop_jumbo(skb, off))
185 						return false;
186 					break;
187 				case IPV6_TLV_CALIPSO:
188 					if (!ipv6_hop_calipso(skb, off))
189 						return false;
190 					break;
191 				default:
192 					if (!ip6_tlvopt_unknown(skb, off,
193 								disallow_unknowns))
194 						return false;
195 					break;
196 				}
197 			} else {
198 				switch (nh[off]) {
199 #if IS_ENABLED(CONFIG_IPV6_MIP6)
200 				case IPV6_TLV_HAO:
201 					if (!ipv6_dest_hao(skb, off))
202 						return false;
203 					break;
204 #endif
205 				default:
206 					if (!ip6_tlvopt_unknown(skb, off,
207 								disallow_unknowns))
208 						return false;
209 					break;
210 				}
211 			}
212 			padlen = 0;
213 		}
214 		off += optlen;
215 		len -= optlen;
216 	}
217 
218 	if (len == 0)
219 		return true;
220 bad:
221 	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
222 	return false;
223 }
224 
225 /*****************************
226   Destination options header.
227  *****************************/
228 
229 #if IS_ENABLED(CONFIG_IPV6_MIP6)
ipv6_dest_hao(struct sk_buff * skb,int optoff)230 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
231 {
232 	struct ipv6_destopt_hao *hao;
233 	struct inet6_skb_parm *opt = IP6CB(skb);
234 	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
235 	SKB_DR(reason);
236 	int ret;
237 
238 	if (opt->dsthao) {
239 		net_dbg_ratelimited("hao duplicated\n");
240 		goto discard;
241 	}
242 	opt->dsthao = opt->dst1;
243 	opt->dst1 = 0;
244 
245 	hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
246 
247 	if (hao->length != 16) {
248 		net_dbg_ratelimited("hao invalid option length = %d\n",
249 				    hao->length);
250 		SKB_DR_SET(reason, IP_INHDR);
251 		goto discard;
252 	}
253 
254 	if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
255 		net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
256 				    &hao->addr);
257 		SKB_DR_SET(reason, INVALID_PROTO);
258 		goto discard;
259 	}
260 
261 	ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
262 			       (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
263 	if (unlikely(ret < 0)) {
264 		SKB_DR_SET(reason, XFRM_POLICY);
265 		goto discard;
266 	}
267 
268 	if (skb_cloned(skb)) {
269 		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
270 			goto discard;
271 
272 		/* update all variable using below by copied skbuff */
273 		hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
274 						  optoff);
275 		ipv6h = ipv6_hdr(skb);
276 	}
277 
278 	if (skb->ip_summed == CHECKSUM_COMPLETE)
279 		skb->ip_summed = CHECKSUM_NONE;
280 
281 	swap(ipv6h->saddr, hao->addr);
282 
283 	if (skb->tstamp == 0)
284 		__net_timestamp(skb);
285 
286 	return true;
287 
288  discard:
289 	kfree_skb_reason(skb, reason);
290 	return false;
291 }
292 #endif
293 
ipv6_destopt_rcv(struct sk_buff * skb)294 static int ipv6_destopt_rcv(struct sk_buff *skb)
295 {
296 	struct inet6_dev *idev = __in6_dev_get(skb->dev);
297 	struct inet6_skb_parm *opt = IP6CB(skb);
298 #if IS_ENABLED(CONFIG_IPV6_MIP6)
299 	__u16 dstbuf;
300 #endif
301 	struct dst_entry *dst = skb_dst(skb);
302 	struct net *net = dev_net(skb->dev);
303 	int extlen;
304 
305 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
306 	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
307 				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
308 		__IP6_INC_STATS(dev_net(dst->dev), idev,
309 				IPSTATS_MIB_INHDRERRORS);
310 fail_and_free:
311 		kfree_skb(skb);
312 		return -1;
313 	}
314 
315 	extlen = (skb_transport_header(skb)[1] + 1) << 3;
316 	if (extlen > net->ipv6.sysctl.max_dst_opts_len)
317 		goto fail_and_free;
318 
319 	opt->lastopt = opt->dst1 = skb_network_header_len(skb);
320 #if IS_ENABLED(CONFIG_IPV6_MIP6)
321 	dstbuf = opt->dst1;
322 #endif
323 
324 	if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) {
325 		skb->transport_header += extlen;
326 		opt = IP6CB(skb);
327 #if IS_ENABLED(CONFIG_IPV6_MIP6)
328 		opt->nhoff = dstbuf;
329 #else
330 		opt->nhoff = opt->dst1;
331 #endif
332 		return 1;
333 	}
334 
335 	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
336 	return -1;
337 }
338 
seg6_update_csum(struct sk_buff * skb)339 static void seg6_update_csum(struct sk_buff *skb)
340 {
341 	struct ipv6_sr_hdr *hdr;
342 	struct in6_addr *addr;
343 	__be32 from, to;
344 
345 	/* srh is at transport offset and seg_left is already decremented
346 	 * but daddr is not yet updated with next segment
347 	 */
348 
349 	hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
350 	addr = hdr->segments + hdr->segments_left;
351 
352 	hdr->segments_left++;
353 	from = *(__be32 *)hdr;
354 
355 	hdr->segments_left--;
356 	to = *(__be32 *)hdr;
357 
358 	/* update skb csum with diff resulting from seg_left decrement */
359 
360 	update_csum_diff4(skb, from, to);
361 
362 	/* compute csum diff between current and next segment and update */
363 
364 	update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
365 			   (__be32 *)addr);
366 }
367 
ipv6_srh_rcv(struct sk_buff * skb)368 static int ipv6_srh_rcv(struct sk_buff *skb)
369 {
370 	struct inet6_skb_parm *opt = IP6CB(skb);
371 	struct net *net = dev_net(skb->dev);
372 	struct ipv6_sr_hdr *hdr;
373 	struct inet6_dev *idev;
374 	struct in6_addr *addr;
375 	int accept_seg6;
376 
377 	hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
378 
379 	idev = __in6_dev_get(skb->dev);
380 
381 	accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
382 	if (accept_seg6 > idev->cnf.seg6_enabled)
383 		accept_seg6 = idev->cnf.seg6_enabled;
384 
385 	if (!accept_seg6) {
386 		kfree_skb(skb);
387 		return -1;
388 	}
389 
390 #ifdef CONFIG_IPV6_SEG6_HMAC
391 	if (!seg6_hmac_validate_skb(skb)) {
392 		kfree_skb(skb);
393 		return -1;
394 	}
395 #endif
396 
397 looped_back:
398 	if (hdr->segments_left == 0) {
399 		if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
400 			int offset = (hdr->hdrlen + 1) << 3;
401 
402 			skb_postpull_rcsum(skb, skb_network_header(skb),
403 					   skb_network_header_len(skb));
404 			skb_pull(skb, offset);
405 			skb_postpull_rcsum(skb, skb_transport_header(skb),
406 					   offset);
407 
408 			skb_reset_network_header(skb);
409 			skb_reset_transport_header(skb);
410 			skb->encapsulation = 0;
411 			if (hdr->nexthdr == NEXTHDR_IPV4)
412 				skb->protocol = htons(ETH_P_IP);
413 			__skb_tunnel_rx(skb, skb->dev, net);
414 
415 			netif_rx(skb);
416 			return -1;
417 		}
418 
419 		opt->srcrt = skb_network_header_len(skb);
420 		opt->lastopt = opt->srcrt;
421 		skb->transport_header += (hdr->hdrlen + 1) << 3;
422 		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
423 
424 		return 1;
425 	}
426 
427 	if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
428 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
429 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
430 				  ((&hdr->segments_left) -
431 				   skb_network_header(skb)));
432 		return -1;
433 	}
434 
435 	if (skb_cloned(skb)) {
436 		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
437 			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
438 					IPSTATS_MIB_OUTDISCARDS);
439 			kfree_skb(skb);
440 			return -1;
441 		}
442 
443 		hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
444 	}
445 
446 	hdr->segments_left--;
447 	addr = hdr->segments + hdr->segments_left;
448 
449 	skb_push(skb, sizeof(struct ipv6hdr));
450 
451 	if (skb->ip_summed == CHECKSUM_COMPLETE)
452 		seg6_update_csum(skb);
453 
454 	ipv6_hdr(skb)->daddr = *addr;
455 
456 	ip6_route_input(skb);
457 
458 	if (skb_dst(skb)->error) {
459 		dst_input(skb);
460 		return -1;
461 	}
462 
463 	if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
464 		if (ipv6_hdr(skb)->hop_limit <= 1) {
465 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
466 			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
467 				    ICMPV6_EXC_HOPLIMIT, 0);
468 			kfree_skb(skb);
469 			return -1;
470 		}
471 		ipv6_hdr(skb)->hop_limit--;
472 
473 		skb_pull(skb, sizeof(struct ipv6hdr));
474 		goto looped_back;
475 	}
476 
477 	dst_input(skb);
478 
479 	return -1;
480 }
481 
ipv6_rpl_srh_rcv(struct sk_buff * skb)482 static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
483 {
484 	struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
485 	struct inet6_skb_parm *opt = IP6CB(skb);
486 	struct net *net = dev_net(skb->dev);
487 	struct inet6_dev *idev;
488 	struct ipv6hdr *oldhdr;
489 	unsigned char *buf;
490 	int accept_rpl_seg;
491 	int i, err;
492 	u64 n = 0;
493 	u32 r;
494 
495 	idev = __in6_dev_get(skb->dev);
496 
497 	accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
498 	if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
499 		accept_rpl_seg = idev->cnf.rpl_seg_enabled;
500 
501 	if (!accept_rpl_seg) {
502 		kfree_skb(skb);
503 		return -1;
504 	}
505 
506 looped_back:
507 	hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
508 
509 	if (hdr->segments_left == 0) {
510 		if (hdr->nexthdr == NEXTHDR_IPV6) {
511 			int offset = (hdr->hdrlen + 1) << 3;
512 
513 			skb_postpull_rcsum(skb, skb_network_header(skb),
514 					   skb_network_header_len(skb));
515 			skb_pull(skb, offset);
516 			skb_postpull_rcsum(skb, skb_transport_header(skb),
517 					   offset);
518 
519 			skb_reset_network_header(skb);
520 			skb_reset_transport_header(skb);
521 			skb->encapsulation = 0;
522 
523 			__skb_tunnel_rx(skb, skb->dev, net);
524 
525 			netif_rx(skb);
526 			return -1;
527 		}
528 
529 		opt->srcrt = skb_network_header_len(skb);
530 		opt->lastopt = opt->srcrt;
531 		skb->transport_header += (hdr->hdrlen + 1) << 3;
532 		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
533 
534 		return 1;
535 	}
536 
537 	n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
538 	r = do_div(n, (16 - hdr->cmpri));
539 	/* checks if calculation was without remainder and n fits into
540 	 * unsigned char which is segments_left field. Should not be
541 	 * higher than that.
542 	 */
543 	if (r || (n + 1) > 255) {
544 		kfree_skb(skb);
545 		return -1;
546 	}
547 
548 	if (hdr->segments_left > n + 1) {
549 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
550 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
551 				  ((&hdr->segments_left) -
552 				   skb_network_header(skb)));
553 		return -1;
554 	}
555 
556 	hdr->segments_left--;
557 	i = n - hdr->segments_left;
558 
559 	buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
560 	if (unlikely(!buf)) {
561 		kfree_skb(skb);
562 		return -1;
563 	}
564 
565 	ohdr = (struct ipv6_rpl_sr_hdr *)buf;
566 	ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
567 	chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
568 
569 	if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) {
570 		kfree_skb(skb);
571 		kfree(buf);
572 		return -1;
573 	}
574 
575 	err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
576 	if (err) {
577 		icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
578 		kfree_skb(skb);
579 		kfree(buf);
580 		return -1;
581 	}
582 
583 	swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]);
584 
585 	ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
586 
587 	oldhdr = ipv6_hdr(skb);
588 
589 	skb_pull(skb, ((hdr->hdrlen + 1) << 3));
590 	skb_postpull_rcsum(skb, oldhdr,
591 			   sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
592 	if (unlikely(!hdr->segments_left)) {
593 		if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
594 				     GFP_ATOMIC)) {
595 			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
596 			kfree_skb(skb);
597 			kfree(buf);
598 			return -1;
599 		}
600 
601 		oldhdr = ipv6_hdr(skb);
602 	}
603 	skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
604 	skb_reset_network_header(skb);
605 	skb_mac_header_rebuild(skb);
606 	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
607 
608 	memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
609 	memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
610 
611 	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
612 	skb_postpush_rcsum(skb, ipv6_hdr(skb),
613 			   sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
614 
615 	kfree(buf);
616 
617 	ip6_route_input(skb);
618 
619 	if (skb_dst(skb)->error) {
620 		dst_input(skb);
621 		return -1;
622 	}
623 
624 	if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
625 		if (ipv6_hdr(skb)->hop_limit <= 1) {
626 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
627 			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
628 				    ICMPV6_EXC_HOPLIMIT, 0);
629 			kfree_skb(skb);
630 			return -1;
631 		}
632 		ipv6_hdr(skb)->hop_limit--;
633 
634 		skb_pull(skb, sizeof(struct ipv6hdr));
635 		goto looped_back;
636 	}
637 
638 	dst_input(skb);
639 
640 	return -1;
641 }
642 
643 /********************************
644   Routing header.
645  ********************************/
646 
647 /* called with rcu_read_lock() */
ipv6_rthdr_rcv(struct sk_buff * skb)648 static int ipv6_rthdr_rcv(struct sk_buff *skb)
649 {
650 	struct inet6_dev *idev = __in6_dev_get(skb->dev);
651 	struct inet6_skb_parm *opt = IP6CB(skb);
652 	struct in6_addr *addr = NULL;
653 	int n, i;
654 	struct ipv6_rt_hdr *hdr;
655 	struct rt0_hdr *rthdr;
656 	struct net *net = dev_net(skb->dev);
657 	int accept_source_route = net->ipv6.devconf_all->accept_source_route;
658 
659 	if (idev && accept_source_route > idev->cnf.accept_source_route)
660 		accept_source_route = idev->cnf.accept_source_route;
661 
662 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
663 	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
664 				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
665 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
666 		kfree_skb(skb);
667 		return -1;
668 	}
669 
670 	hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
671 
672 	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
673 	    skb->pkt_type != PACKET_HOST) {
674 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
675 		kfree_skb(skb);
676 		return -1;
677 	}
678 
679 	switch (hdr->type) {
680 	case IPV6_SRCRT_TYPE_4:
681 		/* segment routing */
682 		return ipv6_srh_rcv(skb);
683 	case IPV6_SRCRT_TYPE_3:
684 		/* rpl segment routing */
685 		return ipv6_rpl_srh_rcv(skb);
686 	default:
687 		break;
688 	}
689 
690 looped_back:
691 	if (hdr->segments_left == 0) {
692 		switch (hdr->type) {
693 #if IS_ENABLED(CONFIG_IPV6_MIP6)
694 		case IPV6_SRCRT_TYPE_2:
695 			/* Silently discard type 2 header unless it was
696 			 * processed by own
697 			 */
698 			if (!addr) {
699 				__IP6_INC_STATS(net, idev,
700 						IPSTATS_MIB_INADDRERRORS);
701 				kfree_skb(skb);
702 				return -1;
703 			}
704 			break;
705 #endif
706 		default:
707 			break;
708 		}
709 
710 		opt->lastopt = opt->srcrt = skb_network_header_len(skb);
711 		skb->transport_header += (hdr->hdrlen + 1) << 3;
712 		opt->dst0 = opt->dst1;
713 		opt->dst1 = 0;
714 		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
715 		return 1;
716 	}
717 
718 	switch (hdr->type) {
719 #if IS_ENABLED(CONFIG_IPV6_MIP6)
720 	case IPV6_SRCRT_TYPE_2:
721 		if (accept_source_route < 0)
722 			goto unknown_rh;
723 		/* Silently discard invalid RTH type 2 */
724 		if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
725 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
726 			kfree_skb(skb);
727 			return -1;
728 		}
729 		break;
730 #endif
731 	default:
732 		goto unknown_rh;
733 	}
734 
735 	/*
736 	 *	This is the routing header forwarding algorithm from
737 	 *	RFC 2460, page 16.
738 	 */
739 
740 	n = hdr->hdrlen >> 1;
741 
742 	if (hdr->segments_left > n) {
743 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
744 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
745 				  ((&hdr->segments_left) -
746 				   skb_network_header(skb)));
747 		return -1;
748 	}
749 
750 	/* We are about to mangle packet header. Be careful!
751 	   Do not damage packets queued somewhere.
752 	 */
753 	if (skb_cloned(skb)) {
754 		/* the copy is a forwarded packet */
755 		if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
756 			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
757 					IPSTATS_MIB_OUTDISCARDS);
758 			kfree_skb(skb);
759 			return -1;
760 		}
761 		hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
762 	}
763 
764 	if (skb->ip_summed == CHECKSUM_COMPLETE)
765 		skb->ip_summed = CHECKSUM_NONE;
766 
767 	i = n - --hdr->segments_left;
768 
769 	rthdr = (struct rt0_hdr *) hdr;
770 	addr = rthdr->addr;
771 	addr += i - 1;
772 
773 	switch (hdr->type) {
774 #if IS_ENABLED(CONFIG_IPV6_MIP6)
775 	case IPV6_SRCRT_TYPE_2:
776 		if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
777 				     (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
778 				     IPPROTO_ROUTING) < 0) {
779 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
780 			kfree_skb(skb);
781 			return -1;
782 		}
783 		if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
784 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
785 			kfree_skb(skb);
786 			return -1;
787 		}
788 		break;
789 #endif
790 	default:
791 		break;
792 	}
793 
794 	if (ipv6_addr_is_multicast(addr)) {
795 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
796 		kfree_skb(skb);
797 		return -1;
798 	}
799 
800 	swap(*addr, ipv6_hdr(skb)->daddr);
801 
802 	ip6_route_input(skb);
803 	if (skb_dst(skb)->error) {
804 		skb_push(skb, skb->data - skb_network_header(skb));
805 		dst_input(skb);
806 		return -1;
807 	}
808 
809 	if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
810 		if (ipv6_hdr(skb)->hop_limit <= 1) {
811 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
812 			icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
813 				    0);
814 			kfree_skb(skb);
815 			return -1;
816 		}
817 		ipv6_hdr(skb)->hop_limit--;
818 		goto looped_back;
819 	}
820 
821 	skb_push(skb, skb->data - skb_network_header(skb));
822 	dst_input(skb);
823 	return -1;
824 
825 unknown_rh:
826 	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
827 	icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
828 			  (&hdr->type) - skb_network_header(skb));
829 	return -1;
830 }
831 
832 static const struct inet6_protocol rthdr_protocol = {
833 	.handler	=	ipv6_rthdr_rcv,
834 	.flags		=	INET6_PROTO_NOPOLICY,
835 };
836 
837 static const struct inet6_protocol destopt_protocol = {
838 	.handler	=	ipv6_destopt_rcv,
839 	.flags		=	INET6_PROTO_NOPOLICY,
840 };
841 
842 static const struct inet6_protocol nodata_protocol = {
843 	.handler	=	dst_discard,
844 	.flags		=	INET6_PROTO_NOPOLICY,
845 };
846 
ipv6_exthdrs_init(void)847 int __init ipv6_exthdrs_init(void)
848 {
849 	int ret;
850 
851 	ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
852 	if (ret)
853 		goto out;
854 
855 	ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
856 	if (ret)
857 		goto out_rthdr;
858 
859 	ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
860 	if (ret)
861 		goto out_destopt;
862 
863 out:
864 	return ret;
865 out_destopt:
866 	inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
867 out_rthdr:
868 	inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
869 	goto out;
870 };
871 
ipv6_exthdrs_exit(void)872 void ipv6_exthdrs_exit(void)
873 {
874 	inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
875 	inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
876 	inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
877 }
878 
879 /**********************************
880   Hop-by-hop options.
881  **********************************/
882 
883 /*
884  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
885  */
ipv6_skb_net(struct sk_buff * skb)886 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
887 {
888 	return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
889 }
890 
891 /* Router Alert as of RFC 2711 */
892 
ipv6_hop_ra(struct sk_buff * skb,int optoff)893 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
894 {
895 	const unsigned char *nh = skb_network_header(skb);
896 
897 	if (nh[optoff + 1] == 2) {
898 		IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
899 		memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
900 		return true;
901 	}
902 	net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
903 			    nh[optoff + 1]);
904 	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
905 	return false;
906 }
907 
908 /* IOAM */
909 
ipv6_hop_ioam(struct sk_buff * skb,int optoff)910 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
911 {
912 	struct ioam6_trace_hdr *trace;
913 	struct ioam6_namespace *ns;
914 	struct ioam6_hdr *hdr;
915 
916 	/* Bad alignment (must be 4n-aligned) */
917 	if (optoff & 3)
918 		goto drop;
919 
920 	/* Ignore if IOAM is not enabled on ingress */
921 	if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
922 		goto ignore;
923 
924 	/* Truncated Option header */
925 	hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
926 	if (hdr->opt_len < 2)
927 		goto drop;
928 
929 	switch (hdr->type) {
930 	case IOAM6_TYPE_PREALLOC:
931 		/* Truncated Pre-allocated Trace header */
932 		if (hdr->opt_len < 2 + sizeof(*trace))
933 			goto drop;
934 
935 		/* Malformed Pre-allocated Trace header */
936 		trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
937 		if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
938 			goto drop;
939 
940 		/* Ignore if the IOAM namespace is unknown */
941 		ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id);
942 		if (!ns)
943 			goto ignore;
944 
945 		if (!skb_valid_dst(skb))
946 			ip6_route_input(skb);
947 
948 		/* About to mangle packet header */
949 		if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len))
950 			goto drop;
951 
952 		/* Trace pointer may have changed */
953 		trace = (struct ioam6_trace_hdr *)(skb_network_header(skb)
954 						   + optoff + sizeof(*hdr));
955 
956 		ioam6_fill_trace_data(skb, ns, trace, true);
957 		break;
958 	default:
959 		break;
960 	}
961 
962 ignore:
963 	return true;
964 
965 drop:
966 	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
967 	return false;
968 }
969 
970 /* Jumbo payload */
971 
ipv6_hop_jumbo(struct sk_buff * skb,int optoff)972 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
973 {
974 	const unsigned char *nh = skb_network_header(skb);
975 	SKB_DR(reason);
976 	u32 pkt_len;
977 
978 	if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
979 		net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
980 				    nh[optoff+1]);
981 		SKB_DR_SET(reason, IP_INHDR);
982 		goto drop;
983 	}
984 
985 	pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
986 	if (pkt_len <= IPV6_MAXPLEN) {
987 		icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2,
988 					 SKB_DROP_REASON_IP_INHDR);
989 		return false;
990 	}
991 	if (ipv6_hdr(skb)->payload_len) {
992 		icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff,
993 					 SKB_DROP_REASON_IP_INHDR);
994 		return false;
995 	}
996 
997 	if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
998 		SKB_DR_SET(reason, PKT_TOO_SMALL);
999 		goto drop;
1000 	}
1001 
1002 	if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1003 		goto drop;
1004 
1005 	IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1006 	return true;
1007 
1008 drop:
1009 	kfree_skb_reason(skb, reason);
1010 	return false;
1011 }
1012 
1013 /* CALIPSO RFC 5570 */
1014 
ipv6_hop_calipso(struct sk_buff * skb,int optoff)1015 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1016 {
1017 	const unsigned char *nh = skb_network_header(skb);
1018 
1019 	if (nh[optoff + 1] < 8)
1020 		goto drop;
1021 
1022 	if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1023 		goto drop;
1024 
1025 	if (!calipso_validate(skb, nh + optoff))
1026 		goto drop;
1027 
1028 	return true;
1029 
1030 drop:
1031 	kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR);
1032 	return false;
1033 }
1034 
ipv6_parse_hopopts(struct sk_buff * skb)1035 int ipv6_parse_hopopts(struct sk_buff *skb)
1036 {
1037 	struct inet6_skb_parm *opt = IP6CB(skb);
1038 	struct net *net = dev_net(skb->dev);
1039 	int extlen;
1040 
1041 	/*
1042 	 * skb_network_header(skb) is equal to skb->data, and
1043 	 * skb_network_header_len(skb) is always equal to
1044 	 * sizeof(struct ipv6hdr) by definition of
1045 	 * hop-by-hop options.
1046 	 */
1047 	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1048 	    !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1049 				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
1050 fail_and_free:
1051 		kfree_skb(skb);
1052 		return -1;
1053 	}
1054 
1055 	extlen = (skb_transport_header(skb)[1] + 1) << 3;
1056 	if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1057 		goto fail_and_free;
1058 
1059 	opt->flags |= IP6SKB_HOPBYHOP;
1060 	if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
1061 		skb->transport_header += extlen;
1062 		opt = IP6CB(skb);
1063 		opt->nhoff = sizeof(struct ipv6hdr);
1064 		return 1;
1065 	}
1066 	return -1;
1067 }
1068 
1069 /*
1070  *	Creating outbound headers.
1071  *
1072  *	"build" functions work when skb is filled from head to tail (datagram)
1073  *	"push"	functions work when headers are added from tail to head (tcp)
1074  *
1075  *	In both cases we assume, that caller reserved enough room
1076  *	for headers.
1077  */
1078 
ipv6_push_rthdr0(struct sk_buff * skb,u8 * proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1079 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1080 			     struct ipv6_rt_hdr *opt,
1081 			     struct in6_addr **addr_p, struct in6_addr *saddr)
1082 {
1083 	struct rt0_hdr *phdr, *ihdr;
1084 	int hops;
1085 
1086 	ihdr = (struct rt0_hdr *) opt;
1087 
1088 	phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1089 	memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1090 
1091 	hops = ihdr->rt_hdr.hdrlen >> 1;
1092 
1093 	if (hops > 1)
1094 		memcpy(phdr->addr, ihdr->addr + 1,
1095 		       (hops - 1) * sizeof(struct in6_addr));
1096 
1097 	phdr->addr[hops - 1] = **addr_p;
1098 	*addr_p = ihdr->addr;
1099 
1100 	phdr->rt_hdr.nexthdr = *proto;
1101 	*proto = NEXTHDR_ROUTING;
1102 }
1103 
ipv6_push_rthdr4(struct sk_buff * skb,u8 * proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1104 static void ipv6_push_rthdr4(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 ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1109 	int plen, hops;
1110 
1111 	sr_ihdr = (struct ipv6_sr_hdr *)opt;
1112 	plen = (sr_ihdr->hdrlen + 1) << 3;
1113 
1114 	sr_phdr = skb_push(skb, plen);
1115 	memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1116 
1117 	hops = sr_ihdr->first_segment + 1;
1118 	memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1119 	       (hops - 1) * sizeof(struct in6_addr));
1120 
1121 	sr_phdr->segments[0] = **addr_p;
1122 	*addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1123 
1124 	if (sr_ihdr->hdrlen > hops * 2) {
1125 		int tlvs_offset, tlvs_length;
1126 
1127 		tlvs_offset = (1 + hops * 2) << 3;
1128 		tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1129 		memcpy((char *)sr_phdr + tlvs_offset,
1130 		       (char *)sr_ihdr + tlvs_offset, tlvs_length);
1131 	}
1132 
1133 #ifdef CONFIG_IPV6_SEG6_HMAC
1134 	if (sr_has_hmac(sr_phdr)) {
1135 		struct net *net = NULL;
1136 
1137 		if (skb->dev)
1138 			net = dev_net(skb->dev);
1139 		else if (skb->sk)
1140 			net = sock_net(skb->sk);
1141 
1142 		WARN_ON(!net);
1143 
1144 		if (net)
1145 			seg6_push_hmac(net, saddr, sr_phdr);
1146 	}
1147 #endif
1148 
1149 	sr_phdr->nexthdr = *proto;
1150 	*proto = NEXTHDR_ROUTING;
1151 }
1152 
ipv6_push_rthdr(struct sk_buff * skb,u8 * proto,struct ipv6_rt_hdr * opt,struct in6_addr ** addr_p,struct in6_addr * saddr)1153 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1154 			    struct ipv6_rt_hdr *opt,
1155 			    struct in6_addr **addr_p, struct in6_addr *saddr)
1156 {
1157 	switch (opt->type) {
1158 	case IPV6_SRCRT_TYPE_0:
1159 	case IPV6_SRCRT_STRICT:
1160 	case IPV6_SRCRT_TYPE_2:
1161 		ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1162 		break;
1163 	case IPV6_SRCRT_TYPE_4:
1164 		ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1165 		break;
1166 	default:
1167 		break;
1168 	}
1169 }
1170 
ipv6_push_exthdr(struct sk_buff * skb,u8 * proto,u8 type,struct ipv6_opt_hdr * opt)1171 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1172 {
1173 	struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1174 
1175 	memcpy(h, opt, ipv6_optlen(opt));
1176 	h->nexthdr = *proto;
1177 	*proto = type;
1178 }
1179 
ipv6_push_nfrag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 * proto,struct in6_addr ** daddr,struct in6_addr * saddr)1180 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1181 			  u8 *proto,
1182 			  struct in6_addr **daddr, struct in6_addr *saddr)
1183 {
1184 	if (opt->srcrt) {
1185 		ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1186 		/*
1187 		 * IPV6_RTHDRDSTOPTS is ignored
1188 		 * unless IPV6_RTHDR is set (RFC3542).
1189 		 */
1190 		if (opt->dst0opt)
1191 			ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1192 	}
1193 	if (opt->hopopt)
1194 		ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1195 }
1196 
ipv6_push_frag_opts(struct sk_buff * skb,struct ipv6_txoptions * opt,u8 * proto)1197 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1198 {
1199 	if (opt->dst1opt)
1200 		ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1201 }
1202 EXPORT_SYMBOL(ipv6_push_frag_opts);
1203 
1204 struct ipv6_txoptions *
ipv6_dup_options(struct sock * sk,struct ipv6_txoptions * opt)1205 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1206 {
1207 	struct ipv6_txoptions *opt2;
1208 
1209 	opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1210 	if (opt2) {
1211 		long dif = (char *)opt2 - (char *)opt;
1212 		memcpy(opt2, opt, opt->tot_len);
1213 		if (opt2->hopopt)
1214 			*((char **)&opt2->hopopt) += dif;
1215 		if (opt2->dst0opt)
1216 			*((char **)&opt2->dst0opt) += dif;
1217 		if (opt2->dst1opt)
1218 			*((char **)&opt2->dst1opt) += dif;
1219 		if (opt2->srcrt)
1220 			*((char **)&opt2->srcrt) += dif;
1221 		refcount_set(&opt2->refcnt, 1);
1222 	}
1223 	return opt2;
1224 }
1225 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1226 
ipv6_renew_option(int renewtype,struct ipv6_opt_hdr ** dest,struct ipv6_opt_hdr * old,struct ipv6_opt_hdr * new,int newtype,char ** p)1227 static void ipv6_renew_option(int renewtype,
1228 			      struct ipv6_opt_hdr **dest,
1229 			      struct ipv6_opt_hdr *old,
1230 			      struct ipv6_opt_hdr *new,
1231 			      int newtype, char **p)
1232 {
1233 	struct ipv6_opt_hdr *src;
1234 
1235 	src = (renewtype == newtype ? new : old);
1236 	if (!src)
1237 		return;
1238 
1239 	memcpy(*p, src, ipv6_optlen(src));
1240 	*dest = (struct ipv6_opt_hdr *)*p;
1241 	*p += CMSG_ALIGN(ipv6_optlen(*dest));
1242 }
1243 
1244 /**
1245  * ipv6_renew_options - replace a specific ext hdr with a new one.
1246  *
1247  * @sk: sock from which to allocate memory
1248  * @opt: original options
1249  * @newtype: option type to replace in @opt
1250  * @newopt: new option of type @newtype to replace (user-mem)
1251  *
1252  * Returns a new set of options which is a copy of @opt with the
1253  * option type @newtype replaced with @newopt.
1254  *
1255  * @opt may be NULL, in which case a new set of options is returned
1256  * containing just @newopt.
1257  *
1258  * @newopt may be NULL, in which case the specified option type is
1259  * not copied into the new set of options.
1260  *
1261  * The new set of options is allocated from the socket option memory
1262  * buffer of @sk.
1263  */
1264 struct ipv6_txoptions *
ipv6_renew_options(struct sock * sk,struct ipv6_txoptions * opt,int newtype,struct ipv6_opt_hdr * newopt)1265 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1266 		   int newtype, struct ipv6_opt_hdr *newopt)
1267 {
1268 	int tot_len = 0;
1269 	char *p;
1270 	struct ipv6_txoptions *opt2;
1271 
1272 	if (opt) {
1273 		if (newtype != IPV6_HOPOPTS && opt->hopopt)
1274 			tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1275 		if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1276 			tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1277 		if (newtype != IPV6_RTHDR && opt->srcrt)
1278 			tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1279 		if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1280 			tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1281 	}
1282 
1283 	if (newopt)
1284 		tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1285 
1286 	if (!tot_len)
1287 		return NULL;
1288 
1289 	tot_len += sizeof(*opt2);
1290 	opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1291 	if (!opt2)
1292 		return ERR_PTR(-ENOBUFS);
1293 
1294 	memset(opt2, 0, tot_len);
1295 	refcount_set(&opt2->refcnt, 1);
1296 	opt2->tot_len = tot_len;
1297 	p = (char *)(opt2 + 1);
1298 
1299 	ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1300 			  (opt ? opt->hopopt : NULL),
1301 			  newopt, newtype, &p);
1302 	ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1303 			  (opt ? opt->dst0opt : NULL),
1304 			  newopt, newtype, &p);
1305 	ipv6_renew_option(IPV6_RTHDR,
1306 			  (struct ipv6_opt_hdr **)&opt2->srcrt,
1307 			  (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1308 			  newopt, newtype, &p);
1309 	ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1310 			  (opt ? opt->dst1opt : NULL),
1311 			  newopt, newtype, &p);
1312 
1313 	opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1314 			  (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1315 			  (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1316 	opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1317 
1318 	return opt2;
1319 }
1320 
__ipv6_fixup_options(struct ipv6_txoptions * opt_space,struct ipv6_txoptions * opt)1321 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1322 					    struct ipv6_txoptions *opt)
1323 {
1324 	/*
1325 	 * ignore the dest before srcrt unless srcrt is being included.
1326 	 * --yoshfuji
1327 	 */
1328 	if (opt->dst0opt && !opt->srcrt) {
1329 		if (opt_space != opt) {
1330 			memcpy(opt_space, opt, sizeof(*opt_space));
1331 			opt = opt_space;
1332 		}
1333 		opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1334 		opt->dst0opt = NULL;
1335 	}
1336 
1337 	return opt;
1338 }
1339 EXPORT_SYMBOL_GPL(__ipv6_fixup_options);
1340 
1341 /**
1342  * fl6_update_dst - update flowi destination address with info given
1343  *                  by srcrt option, if any.
1344  *
1345  * @fl6: flowi6 for which daddr is to be updated
1346  * @opt: struct ipv6_txoptions in which to look for srcrt opt
1347  * @orig: copy of original daddr address if modified
1348  *
1349  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1350  * and initial value of fl6->daddr set in orig
1351  */
fl6_update_dst(struct flowi6 * fl6,const struct ipv6_txoptions * opt,struct in6_addr * orig)1352 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1353 				const struct ipv6_txoptions *opt,
1354 				struct in6_addr *orig)
1355 {
1356 	if (!opt || !opt->srcrt)
1357 		return NULL;
1358 
1359 	*orig = fl6->daddr;
1360 
1361 	switch (opt->srcrt->type) {
1362 	case IPV6_SRCRT_TYPE_0:
1363 	case IPV6_SRCRT_STRICT:
1364 	case IPV6_SRCRT_TYPE_2:
1365 		fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1366 		break;
1367 	case IPV6_SRCRT_TYPE_4:
1368 	{
1369 		struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1370 
1371 		fl6->daddr = srh->segments[srh->segments_left];
1372 		break;
1373 	}
1374 	default:
1375 		return NULL;
1376 	}
1377 
1378 	return orig;
1379 }
1380 EXPORT_SYMBOL_GPL(fl6_update_dst);
1381