xref: /linux/net/ipv6/datagram.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
1 /*
2  *	common UDP/RAW code
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	This program is free software; you can redistribute it and/or
9  *      modify it under the terms of the GNU General Public License
10  *      as published by the Free Software Foundation; either version
11  *      2 of the License, or (at your option) any later version.
12  */
13 
14 #include <linux/capability.h>
15 #include <linux/errno.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/interrupt.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/in6.h>
22 #include <linux/ipv6.h>
23 #include <linux/route.h>
24 
25 #include <net/ipv6.h>
26 #include <net/ndisc.h>
27 #include <net/addrconf.h>
28 #include <net/transp_v6.h>
29 #include <net/ip6_route.h>
30 #include <net/tcp_states.h>
31 
32 #include <linux/errqueue.h>
33 #include <asm/uaccess.h>
34 
35 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
36 {
37 	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;
38 	struct inet_sock      	*inet = inet_sk(sk);
39 	struct ipv6_pinfo      	*np = inet6_sk(sk);
40 	struct in6_addr		*daddr, *final_p = NULL, final;
41 	struct dst_entry	*dst;
42 	struct flowi		fl;
43 	struct ip6_flowlabel	*flowlabel = NULL;
44 	int			addr_type;
45 	int			err;
46 
47 	if (usin->sin6_family == AF_INET) {
48 		if (__ipv6_only_sock(sk))
49 			return -EAFNOSUPPORT;
50 		err = ip4_datagram_connect(sk, uaddr, addr_len);
51 		goto ipv4_connected;
52 	}
53 
54 	if (addr_len < SIN6_LEN_RFC2133)
55 		return -EINVAL;
56 
57 	if (usin->sin6_family != AF_INET6)
58 		return -EAFNOSUPPORT;
59 
60 	memset(&fl, 0, sizeof(fl));
61 	if (np->sndflow) {
62 		fl.fl6_flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
63 		if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
64 			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
65 			if (flowlabel == NULL)
66 				return -EINVAL;
67 			ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
68 		}
69 	}
70 
71 	addr_type = ipv6_addr_type(&usin->sin6_addr);
72 
73 	if (addr_type == IPV6_ADDR_ANY) {
74 		/*
75 		 *	connect to self
76 		 */
77 		usin->sin6_addr.s6_addr[15] = 0x01;
78 	}
79 
80 	daddr = &usin->sin6_addr;
81 
82 	if (addr_type == IPV6_ADDR_MAPPED) {
83 		struct sockaddr_in sin;
84 
85 		if (__ipv6_only_sock(sk)) {
86 			err = -ENETUNREACH;
87 			goto out;
88 		}
89 		sin.sin_family = AF_INET;
90 		sin.sin_addr.s_addr = daddr->s6_addr32[3];
91 		sin.sin_port = usin->sin6_port;
92 
93 		err = ip4_datagram_connect(sk,
94 					   (struct sockaddr*) &sin,
95 					   sizeof(sin));
96 
97 ipv4_connected:
98 		if (err)
99 			goto out;
100 
101 		ipv6_addr_set(&np->daddr, 0, 0, htonl(0x0000ffff), inet->daddr);
102 
103 		if (ipv6_addr_any(&np->saddr)) {
104 			ipv6_addr_set(&np->saddr, 0, 0, htonl(0x0000ffff),
105 				      inet->saddr);
106 		}
107 
108 		if (ipv6_addr_any(&np->rcv_saddr)) {
109 			ipv6_addr_set(&np->rcv_saddr, 0, 0, htonl(0x0000ffff),
110 				      inet->rcv_saddr);
111 		}
112 		goto out;
113 	}
114 
115 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
116 		if (addr_len >= sizeof(struct sockaddr_in6) &&
117 		    usin->sin6_scope_id) {
118 			if (sk->sk_bound_dev_if &&
119 			    sk->sk_bound_dev_if != usin->sin6_scope_id) {
120 				err = -EINVAL;
121 				goto out;
122 			}
123 			sk->sk_bound_dev_if = usin->sin6_scope_id;
124 		}
125 
126 		if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
127 			sk->sk_bound_dev_if = np->mcast_oif;
128 
129 		/* Connect to link-local address requires an interface */
130 		if (!sk->sk_bound_dev_if) {
131 			err = -EINVAL;
132 			goto out;
133 		}
134 	}
135 
136 	ipv6_addr_copy(&np->daddr, daddr);
137 	np->flow_label = fl.fl6_flowlabel;
138 
139 	inet->dport = usin->sin6_port;
140 
141 	/*
142 	 *	Check for a route to destination an obtain the
143 	 *	destination cache for it.
144 	 */
145 
146 	fl.proto = sk->sk_protocol;
147 	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
148 	ipv6_addr_copy(&fl.fl6_src, &np->saddr);
149 	fl.oif = sk->sk_bound_dev_if;
150 	fl.fl_ip_dport = inet->dport;
151 	fl.fl_ip_sport = inet->sport;
152 
153 	if (!fl.oif && (addr_type&IPV6_ADDR_MULTICAST))
154 		fl.oif = np->mcast_oif;
155 
156 	security_sk_classify_flow(sk, &fl);
157 
158 	if (flowlabel) {
159 		if (flowlabel->opt && flowlabel->opt->srcrt) {
160 			struct rt0_hdr *rt0 = (struct rt0_hdr *) flowlabel->opt->srcrt;
161 			ipv6_addr_copy(&final, &fl.fl6_dst);
162 			ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
163 			final_p = &final;
164 		}
165 	} else if (np->opt && np->opt->srcrt) {
166 		struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
167 		ipv6_addr_copy(&final, &fl.fl6_dst);
168 		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
169 		final_p = &final;
170 	}
171 
172 	err = ip6_dst_lookup(sk, &dst, &fl);
173 	if (err)
174 		goto out;
175 	if (final_p)
176 		ipv6_addr_copy(&fl.fl6_dst, final_p);
177 
178 	if ((err = __xfrm_lookup(&dst, &fl, sk, XFRM_LOOKUP_WAIT)) < 0) {
179 		if (err == -EREMOTE)
180 			err = ip6_dst_blackhole(sk, &dst, &fl);
181 		if (err < 0)
182 			goto out;
183 	}
184 
185 	/* source address lookup done in ip6_dst_lookup */
186 
187 	if (ipv6_addr_any(&np->saddr))
188 		ipv6_addr_copy(&np->saddr, &fl.fl6_src);
189 
190 	if (ipv6_addr_any(&np->rcv_saddr)) {
191 		ipv6_addr_copy(&np->rcv_saddr, &fl.fl6_src);
192 		inet->rcv_saddr = LOOPBACK4_IPV6;
193 	}
194 
195 	ip6_dst_store(sk, dst,
196 		      ipv6_addr_equal(&fl.fl6_dst, &np->daddr) ?
197 		      &np->daddr : NULL,
198 #ifdef CONFIG_IPV6_SUBTREES
199 		      ipv6_addr_equal(&fl.fl6_src, &np->saddr) ?
200 		      &np->saddr :
201 #endif
202 		      NULL);
203 
204 	sk->sk_state = TCP_ESTABLISHED;
205 out:
206 	fl6_sock_release(flowlabel);
207 	return err;
208 }
209 
210 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
211 		     __be16 port, u32 info, u8 *payload)
212 {
213 	struct ipv6_pinfo *np  = inet6_sk(sk);
214 	struct icmp6hdr *icmph = icmp6_hdr(skb);
215 	struct sock_exterr_skb *serr;
216 
217 	if (!np->recverr)
218 		return;
219 
220 	skb = skb_clone(skb, GFP_ATOMIC);
221 	if (!skb)
222 		return;
223 
224 	serr = SKB_EXT_ERR(skb);
225 	serr->ee.ee_errno = err;
226 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
227 	serr->ee.ee_type = icmph->icmp6_type;
228 	serr->ee.ee_code = icmph->icmp6_code;
229 	serr->ee.ee_pad = 0;
230 	serr->ee.ee_info = info;
231 	serr->ee.ee_data = 0;
232 	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
233 				  skb_network_header(skb);
234 	serr->port = port;
235 
236 	__skb_pull(skb, payload - skb->data);
237 	skb_reset_transport_header(skb);
238 
239 	if (sock_queue_err_skb(sk, skb))
240 		kfree_skb(skb);
241 }
242 
243 void ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info)
244 {
245 	struct ipv6_pinfo *np = inet6_sk(sk);
246 	struct sock_exterr_skb *serr;
247 	struct ipv6hdr *iph;
248 	struct sk_buff *skb;
249 
250 	if (!np->recverr)
251 		return;
252 
253 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
254 	if (!skb)
255 		return;
256 
257 	skb_put(skb, sizeof(struct ipv6hdr));
258 	skb_reset_network_header(skb);
259 	iph = ipv6_hdr(skb);
260 	ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);
261 
262 	serr = SKB_EXT_ERR(skb);
263 	serr->ee.ee_errno = err;
264 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
265 	serr->ee.ee_type = 0;
266 	serr->ee.ee_code = 0;
267 	serr->ee.ee_pad = 0;
268 	serr->ee.ee_info = info;
269 	serr->ee.ee_data = 0;
270 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
271 	serr->port = fl->fl_ip_dport;
272 
273 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
274 	skb_reset_transport_header(skb);
275 
276 	if (sock_queue_err_skb(sk, skb))
277 		kfree_skb(skb);
278 }
279 
280 /*
281  *	Handle MSG_ERRQUEUE
282  */
283 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
284 {
285 	struct ipv6_pinfo *np = inet6_sk(sk);
286 	struct sock_exterr_skb *serr;
287 	struct sk_buff *skb, *skb2;
288 	struct sockaddr_in6 *sin;
289 	struct {
290 		struct sock_extended_err ee;
291 		struct sockaddr_in6	 offender;
292 	} errhdr;
293 	int err;
294 	int copied;
295 
296 	err = -EAGAIN;
297 	skb = skb_dequeue(&sk->sk_error_queue);
298 	if (skb == NULL)
299 		goto out;
300 
301 	copied = skb->len;
302 	if (copied > len) {
303 		msg->msg_flags |= MSG_TRUNC;
304 		copied = len;
305 	}
306 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
307 	if (err)
308 		goto out_free_skb;
309 
310 	sock_recv_timestamp(msg, sk, skb);
311 
312 	serr = SKB_EXT_ERR(skb);
313 
314 	sin = (struct sockaddr_in6 *)msg->msg_name;
315 	if (sin) {
316 		const unsigned char *nh = skb_network_header(skb);
317 		sin->sin6_family = AF_INET6;
318 		sin->sin6_flowinfo = 0;
319 		sin->sin6_port = serr->port;
320 		sin->sin6_scope_id = 0;
321 		if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6) {
322 			ipv6_addr_copy(&sin->sin6_addr,
323 				  (struct in6_addr *)(nh + serr->addr_offset));
324 			if (np->sndflow)
325 				sin->sin6_flowinfo =
326 					(*(__be32 *)(nh + serr->addr_offset - 24) &
327 					 IPV6_FLOWINFO_MASK);
328 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
329 				sin->sin6_scope_id = IP6CB(skb)->iif;
330 		} else {
331 			ipv6_addr_set(&sin->sin6_addr, 0, 0,
332 				      htonl(0xffff),
333 				      *(__be32 *)(nh + serr->addr_offset));
334 		}
335 	}
336 
337 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
338 	sin = &errhdr.offender;
339 	sin->sin6_family = AF_UNSPEC;
340 	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
341 		sin->sin6_family = AF_INET6;
342 		sin->sin6_flowinfo = 0;
343 		sin->sin6_scope_id = 0;
344 		if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6) {
345 			ipv6_addr_copy(&sin->sin6_addr, &ipv6_hdr(skb)->saddr);
346 			if (np->rxopt.all)
347 				datagram_recv_ctl(sk, msg, skb);
348 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
349 				sin->sin6_scope_id = IP6CB(skb)->iif;
350 		} else {
351 			struct inet_sock *inet = inet_sk(sk);
352 
353 			ipv6_addr_set(&sin->sin6_addr, 0, 0,
354 				      htonl(0xffff), ip_hdr(skb)->saddr);
355 			if (inet->cmsg_flags)
356 				ip_cmsg_recv(msg, skb);
357 		}
358 	}
359 
360 	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
361 
362 	/* Now we could try to dump offended packet options */
363 
364 	msg->msg_flags |= MSG_ERRQUEUE;
365 	err = copied;
366 
367 	/* Reset and regenerate socket error */
368 	spin_lock_bh(&sk->sk_error_queue.lock);
369 	sk->sk_err = 0;
370 	if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
371 		sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
372 		spin_unlock_bh(&sk->sk_error_queue.lock);
373 		sk->sk_error_report(sk);
374 	} else {
375 		spin_unlock_bh(&sk->sk_error_queue.lock);
376 	}
377 
378 out_free_skb:
379 	kfree_skb(skb);
380 out:
381 	return err;
382 }
383 
384 
385 
386 int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
387 {
388 	struct ipv6_pinfo *np = inet6_sk(sk);
389 	struct inet6_skb_parm *opt = IP6CB(skb);
390 	unsigned char *nh = skb_network_header(skb);
391 
392 	if (np->rxopt.bits.rxinfo) {
393 		struct in6_pktinfo src_info;
394 
395 		src_info.ipi6_ifindex = opt->iif;
396 		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
397 		put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
398 	}
399 
400 	if (np->rxopt.bits.rxhlim) {
401 		int hlim = ipv6_hdr(skb)->hop_limit;
402 		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
403 	}
404 
405 	if (np->rxopt.bits.rxtclass) {
406 		int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
407 		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
408 	}
409 
410 	if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
411 		__be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
412 		put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
413 	}
414 
415 	/* HbH is allowed only once */
416 	if (np->rxopt.bits.hopopts && opt->hop) {
417 		u8 *ptr = nh + opt->hop;
418 		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
419 	}
420 
421 	if (opt->lastopt &&
422 	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
423 		/*
424 		 * Silly enough, but we need to reparse in order to
425 		 * report extension headers (except for HbH)
426 		 * in order.
427 		 *
428 		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
429 		 * (and WILL NOT be) defined because
430 		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
431 		 */
432 		unsigned int off = sizeof(struct ipv6hdr);
433 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
434 
435 		while (off <= opt->lastopt) {
436 			unsigned len;
437 			u8 *ptr = nh + off;
438 
439 			switch(nexthdr) {
440 			case IPPROTO_DSTOPTS:
441 				nexthdr = ptr[0];
442 				len = (ptr[1] + 1) << 3;
443 				if (np->rxopt.bits.dstopts)
444 					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
445 				break;
446 			case IPPROTO_ROUTING:
447 				nexthdr = ptr[0];
448 				len = (ptr[1] + 1) << 3;
449 				if (np->rxopt.bits.srcrt)
450 					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
451 				break;
452 			case IPPROTO_AH:
453 				nexthdr = ptr[0];
454 				len = (ptr[1] + 2) << 2;
455 				break;
456 			default:
457 				nexthdr = ptr[0];
458 				len = (ptr[1] + 1) << 3;
459 				break;
460 			}
461 
462 			off += len;
463 		}
464 	}
465 
466 	/* socket options in old style */
467 	if (np->rxopt.bits.rxoinfo) {
468 		struct in6_pktinfo src_info;
469 
470 		src_info.ipi6_ifindex = opt->iif;
471 		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
472 		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
473 	}
474 	if (np->rxopt.bits.rxohlim) {
475 		int hlim = ipv6_hdr(skb)->hop_limit;
476 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
477 	}
478 	if (np->rxopt.bits.ohopopts && opt->hop) {
479 		u8 *ptr = nh + opt->hop;
480 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
481 	}
482 	if (np->rxopt.bits.odstopts && opt->dst0) {
483 		u8 *ptr = nh + opt->dst0;
484 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
485 	}
486 	if (np->rxopt.bits.osrcrt && opt->srcrt) {
487 		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
488 		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
489 	}
490 	if (np->rxopt.bits.odstopts && opt->dst1) {
491 		u8 *ptr = nh + opt->dst1;
492 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
493 	}
494 	return 0;
495 }
496 
497 int datagram_send_ctl(struct net *net,
498 		      struct msghdr *msg, struct flowi *fl,
499 		      struct ipv6_txoptions *opt,
500 		      int *hlimit, int *tclass)
501 {
502 	struct in6_pktinfo *src_info;
503 	struct cmsghdr *cmsg;
504 	struct ipv6_rt_hdr *rthdr;
505 	struct ipv6_opt_hdr *hdr;
506 	int len;
507 	int err = 0;
508 
509 	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
510 		int addr_type;
511 
512 		if (!CMSG_OK(msg, cmsg)) {
513 			err = -EINVAL;
514 			goto exit_f;
515 		}
516 
517 		if (cmsg->cmsg_level != SOL_IPV6)
518 			continue;
519 
520 		switch (cmsg->cmsg_type) {
521 		case IPV6_PKTINFO:
522 		case IPV6_2292PKTINFO:
523 		    {
524 			struct net_device *dev = NULL;
525 
526 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
527 				err = -EINVAL;
528 				goto exit_f;
529 			}
530 
531 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
532 
533 			if (src_info->ipi6_ifindex) {
534 				if (fl->oif && src_info->ipi6_ifindex != fl->oif)
535 					return -EINVAL;
536 				fl->oif = src_info->ipi6_ifindex;
537 			}
538 
539 			addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
540 
541 			if (fl->oif) {
542 				dev = dev_get_by_index(net, fl->oif);
543 				if (!dev)
544 					return -ENODEV;
545 			} else if (addr_type & IPV6_ADDR_LINKLOCAL)
546 				return -EINVAL;
547 
548 			if (addr_type != IPV6_ADDR_ANY) {
549 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
550 				if (!ipv6_chk_addr(net, &src_info->ipi6_addr,
551 						   strict ? dev : NULL, 0))
552 					err = -EINVAL;
553 				else
554 					ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
555 			}
556 
557 			if (dev)
558 				dev_put(dev);
559 
560 			if (err)
561 				goto exit_f;
562 
563 			break;
564 		    }
565 
566 		case IPV6_FLOWINFO:
567 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
568 				err = -EINVAL;
569 				goto exit_f;
570 			}
571 
572 			if (fl->fl6_flowlabel&IPV6_FLOWINFO_MASK) {
573 				if ((fl->fl6_flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
574 					err = -EINVAL;
575 					goto exit_f;
576 				}
577 			}
578 			fl->fl6_flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
579 			break;
580 
581 		case IPV6_2292HOPOPTS:
582 		case IPV6_HOPOPTS:
583 			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
584 				err = -EINVAL;
585 				goto exit_f;
586 			}
587 
588 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
589 			len = ((hdr->hdrlen + 1) << 3);
590 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
591 				err = -EINVAL;
592 				goto exit_f;
593 			}
594 			if (!capable(CAP_NET_RAW)) {
595 				err = -EPERM;
596 				goto exit_f;
597 			}
598 			opt->opt_nflen += len;
599 			opt->hopopt = hdr;
600 			break;
601 
602 		case IPV6_2292DSTOPTS:
603 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
604 				err = -EINVAL;
605 				goto exit_f;
606 			}
607 
608 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
609 			len = ((hdr->hdrlen + 1) << 3);
610 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
611 				err = -EINVAL;
612 				goto exit_f;
613 			}
614 			if (!capable(CAP_NET_RAW)) {
615 				err = -EPERM;
616 				goto exit_f;
617 			}
618 			if (opt->dst1opt) {
619 				err = -EINVAL;
620 				goto exit_f;
621 			}
622 			opt->opt_flen += len;
623 			opt->dst1opt = hdr;
624 			break;
625 
626 		case IPV6_DSTOPTS:
627 		case IPV6_RTHDRDSTOPTS:
628 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
629 				err = -EINVAL;
630 				goto exit_f;
631 			}
632 
633 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
634 			len = ((hdr->hdrlen + 1) << 3);
635 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
636 				err = -EINVAL;
637 				goto exit_f;
638 			}
639 			if (!capable(CAP_NET_RAW)) {
640 				err = -EPERM;
641 				goto exit_f;
642 			}
643 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
644 				opt->opt_flen += len;
645 				opt->dst1opt = hdr;
646 			} else {
647 				opt->opt_nflen += len;
648 				opt->dst0opt = hdr;
649 			}
650 			break;
651 
652 		case IPV6_2292RTHDR:
653 		case IPV6_RTHDR:
654 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
655 				err = -EINVAL;
656 				goto exit_f;
657 			}
658 
659 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
660 
661 			switch (rthdr->type) {
662 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
663 			case IPV6_SRCRT_TYPE_2:
664 				break;
665 #endif
666 			default:
667 				err = -EINVAL;
668 				goto exit_f;
669 			}
670 
671 			len = ((rthdr->hdrlen + 1) << 3);
672 
673 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
674 				err = -EINVAL;
675 				goto exit_f;
676 			}
677 
678 			/* segments left must also match */
679 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
680 				err = -EINVAL;
681 				goto exit_f;
682 			}
683 
684 			opt->opt_nflen += len;
685 			opt->srcrt = rthdr;
686 
687 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
688 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
689 
690 				opt->opt_nflen += dsthdrlen;
691 				opt->dst0opt = opt->dst1opt;
692 				opt->dst1opt = NULL;
693 				opt->opt_flen -= dsthdrlen;
694 			}
695 
696 			break;
697 
698 		case IPV6_2292HOPLIMIT:
699 		case IPV6_HOPLIMIT:
700 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
701 				err = -EINVAL;
702 				goto exit_f;
703 			}
704 
705 			*hlimit = *(int *)CMSG_DATA(cmsg);
706 			if (*hlimit < -1 || *hlimit > 0xff) {
707 				err = -EINVAL;
708 				goto exit_f;
709 			}
710 
711 			break;
712 
713 		case IPV6_TCLASS:
714 		    {
715 			int tc;
716 
717 			err = -EINVAL;
718 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
719 				goto exit_f;
720 			}
721 
722 			tc = *(int *)CMSG_DATA(cmsg);
723 			if (tc < -1 || tc > 0xff)
724 				goto exit_f;
725 
726 			err = 0;
727 			*tclass = tc;
728 
729 			break;
730 		    }
731 		default:
732 			LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
733 				       cmsg->cmsg_type);
734 			err = -EINVAL;
735 			goto exit_f;
736 		}
737 	}
738 
739 exit_f:
740 	return err;
741 }
742