xref: /linux/net/ipv6/datagram.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5)
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 #include <linux/slab.h>
25 
26 #include <net/ipv6.h>
27 #include <net/ndisc.h>
28 #include <net/addrconf.h>
29 #include <net/transp_v6.h>
30 #include <net/ip6_route.h>
31 #include <net/tcp_states.h>
32 
33 #include <linux/errqueue.h>
34 #include <asm/uaccess.h>
35 
36 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
37 {
38 	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;
39 	struct inet_sock      	*inet = inet_sk(sk);
40 	struct ipv6_pinfo      	*np = inet6_sk(sk);
41 	struct in6_addr		*daddr, *final_p = NULL, final;
42 	struct dst_entry	*dst;
43 	struct flowi		fl;
44 	struct ip6_flowlabel	*flowlabel = NULL;
45 	int			addr_type;
46 	int			err;
47 
48 	if (usin->sin6_family == AF_INET) {
49 		if (__ipv6_only_sock(sk))
50 			return -EAFNOSUPPORT;
51 		err = ip4_datagram_connect(sk, uaddr, addr_len);
52 		goto ipv4_connected;
53 	}
54 
55 	if (addr_len < SIN6_LEN_RFC2133)
56 		return -EINVAL;
57 
58 	if (usin->sin6_family != AF_INET6)
59 		return -EAFNOSUPPORT;
60 
61 	memset(&fl, 0, sizeof(fl));
62 	if (np->sndflow) {
63 		fl.fl6_flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
64 		if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
65 			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
66 			if (flowlabel == NULL)
67 				return -EINVAL;
68 			ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
69 		}
70 	}
71 
72 	addr_type = ipv6_addr_type(&usin->sin6_addr);
73 
74 	if (addr_type == IPV6_ADDR_ANY) {
75 		/*
76 		 *	connect to self
77 		 */
78 		usin->sin6_addr.s6_addr[15] = 0x01;
79 	}
80 
81 	daddr = &usin->sin6_addr;
82 
83 	if (addr_type == IPV6_ADDR_MAPPED) {
84 		struct sockaddr_in sin;
85 
86 		if (__ipv6_only_sock(sk)) {
87 			err = -ENETUNREACH;
88 			goto out;
89 		}
90 		sin.sin_family = AF_INET;
91 		sin.sin_addr.s_addr = daddr->s6_addr32[3];
92 		sin.sin_port = usin->sin6_port;
93 
94 		err = ip4_datagram_connect(sk,
95 					   (struct sockaddr*) &sin,
96 					   sizeof(sin));
97 
98 ipv4_connected:
99 		if (err)
100 			goto out;
101 
102 		ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
103 
104 		if (ipv6_addr_any(&np->saddr))
105 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
106 
107 		if (ipv6_addr_any(&np->rcv_saddr))
108 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
109 					       &np->rcv_saddr);
110 
111 		goto out;
112 	}
113 
114 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
115 		if (addr_len >= sizeof(struct sockaddr_in6) &&
116 		    usin->sin6_scope_id) {
117 			if (sk->sk_bound_dev_if &&
118 			    sk->sk_bound_dev_if != usin->sin6_scope_id) {
119 				err = -EINVAL;
120 				goto out;
121 			}
122 			sk->sk_bound_dev_if = usin->sin6_scope_id;
123 		}
124 
125 		if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
126 			sk->sk_bound_dev_if = np->mcast_oif;
127 
128 		/* Connect to link-local address requires an interface */
129 		if (!sk->sk_bound_dev_if) {
130 			err = -EINVAL;
131 			goto out;
132 		}
133 	}
134 
135 	ipv6_addr_copy(&np->daddr, daddr);
136 	np->flow_label = fl.fl6_flowlabel;
137 
138 	inet->inet_dport = usin->sin6_port;
139 
140 	/*
141 	 *	Check for a route to destination an obtain the
142 	 *	destination cache for it.
143 	 */
144 
145 	fl.proto = sk->sk_protocol;
146 	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
147 	ipv6_addr_copy(&fl.fl6_src, &np->saddr);
148 	fl.oif = sk->sk_bound_dev_if;
149 	fl.mark = sk->sk_mark;
150 	fl.fl_ip_dport = inet->inet_dport;
151 	fl.fl_ip_sport = inet->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 	err = __xfrm_lookup(sock_net(sk), &dst, &fl, sk, XFRM_LOOKUP_WAIT);
179 	if (err < 0) {
180 		if (err == -EREMOTE)
181 			err = ip6_dst_blackhole(sk, &dst, &fl);
182 		if (err < 0)
183 			goto out;
184 	}
185 
186 	/* source address lookup done in ip6_dst_lookup */
187 
188 	if (ipv6_addr_any(&np->saddr))
189 		ipv6_addr_copy(&np->saddr, &fl.fl6_src);
190 
191 	if (ipv6_addr_any(&np->rcv_saddr)) {
192 		ipv6_addr_copy(&np->rcv_saddr, &fl.fl6_src);
193 		inet->inet_rcv_saddr = LOOPBACK4_IPV6;
194 	}
195 
196 	ip6_dst_store(sk, dst,
197 		      ipv6_addr_equal(&fl.fl6_dst, &np->daddr) ?
198 		      &np->daddr : NULL,
199 #ifdef CONFIG_IPV6_SUBTREES
200 		      ipv6_addr_equal(&fl.fl6_src, &np->saddr) ?
201 		      &np->saddr :
202 #endif
203 		      NULL);
204 
205 	sk->sk_state = TCP_ESTABLISHED;
206 out:
207 	fl6_sock_release(flowlabel);
208 	return err;
209 }
210 
211 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
212 		     __be16 port, u32 info, u8 *payload)
213 {
214 	struct ipv6_pinfo *np  = inet6_sk(sk);
215 	struct icmp6hdr *icmph = icmp6_hdr(skb);
216 	struct sock_exterr_skb *serr;
217 
218 	if (!np->recverr)
219 		return;
220 
221 	skb = skb_clone(skb, GFP_ATOMIC);
222 	if (!skb)
223 		return;
224 
225 	serr = SKB_EXT_ERR(skb);
226 	serr->ee.ee_errno = err;
227 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
228 	serr->ee.ee_type = icmph->icmp6_type;
229 	serr->ee.ee_code = icmph->icmp6_code;
230 	serr->ee.ee_pad = 0;
231 	serr->ee.ee_info = info;
232 	serr->ee.ee_data = 0;
233 	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
234 				  skb_network_header(skb);
235 	serr->port = port;
236 
237 	__skb_pull(skb, payload - skb->data);
238 	skb_reset_transport_header(skb);
239 
240 	if (sock_queue_err_skb(sk, skb))
241 		kfree_skb(skb);
242 }
243 
244 void ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info)
245 {
246 	struct ipv6_pinfo *np = inet6_sk(sk);
247 	struct sock_exterr_skb *serr;
248 	struct ipv6hdr *iph;
249 	struct sk_buff *skb;
250 
251 	if (!np->recverr)
252 		return;
253 
254 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
255 	if (!skb)
256 		return;
257 
258 	skb_put(skb, sizeof(struct ipv6hdr));
259 	skb_reset_network_header(skb);
260 	iph = ipv6_hdr(skb);
261 	ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);
262 
263 	serr = SKB_EXT_ERR(skb);
264 	serr->ee.ee_errno = err;
265 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
266 	serr->ee.ee_type = 0;
267 	serr->ee.ee_code = 0;
268 	serr->ee.ee_pad = 0;
269 	serr->ee.ee_info = info;
270 	serr->ee.ee_data = 0;
271 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
272 	serr->port = fl->fl_ip_dport;
273 
274 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
275 	skb_reset_transport_header(skb);
276 
277 	if (sock_queue_err_skb(sk, skb))
278 		kfree_skb(skb);
279 }
280 
281 /*
282  *	Handle MSG_ERRQUEUE
283  */
284 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
285 {
286 	struct ipv6_pinfo *np = inet6_sk(sk);
287 	struct sock_exterr_skb *serr;
288 	struct sk_buff *skb, *skb2;
289 	struct sockaddr_in6 *sin;
290 	struct {
291 		struct sock_extended_err ee;
292 		struct sockaddr_in6	 offender;
293 	} errhdr;
294 	int err;
295 	int copied;
296 
297 	err = -EAGAIN;
298 	skb = skb_dequeue(&sk->sk_error_queue);
299 	if (skb == NULL)
300 		goto out;
301 
302 	copied = skb->len;
303 	if (copied > len) {
304 		msg->msg_flags |= MSG_TRUNC;
305 		copied = len;
306 	}
307 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
308 	if (err)
309 		goto out_free_skb;
310 
311 	sock_recv_timestamp(msg, sk, skb);
312 
313 	serr = SKB_EXT_ERR(skb);
314 
315 	sin = (struct sockaddr_in6 *)msg->msg_name;
316 	if (sin) {
317 		const unsigned char *nh = skb_network_header(skb);
318 		sin->sin6_family = AF_INET6;
319 		sin->sin6_flowinfo = 0;
320 		sin->sin6_port = serr->port;
321 		sin->sin6_scope_id = 0;
322 		if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6) {
323 			ipv6_addr_copy(&sin->sin6_addr,
324 				  (struct in6_addr *)(nh + serr->addr_offset));
325 			if (np->sndflow)
326 				sin->sin6_flowinfo =
327 					(*(__be32 *)(nh + serr->addr_offset - 24) &
328 					 IPV6_FLOWINFO_MASK);
329 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
330 				sin->sin6_scope_id = IP6CB(skb)->iif;
331 		} else {
332 			ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
333 					       &sin->sin6_addr);
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_v4mapped(ip_hdr(skb)->saddr,
354 					       &sin->sin6_addr);
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 			rcu_read_lock();
542 			if (fl->oif) {
543 				dev = dev_get_by_index_rcu(net, fl->oif);
544 				if (!dev) {
545 					rcu_read_unlock();
546 					return -ENODEV;
547 				}
548 			} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
549 				rcu_read_unlock();
550 				return -EINVAL;
551 			}
552 
553 			if (addr_type != IPV6_ADDR_ANY) {
554 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
555 				if (!ipv6_chk_addr(net, &src_info->ipi6_addr,
556 						   strict ? dev : NULL, 0))
557 					err = -EINVAL;
558 				else
559 					ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
560 			}
561 
562 			rcu_read_unlock();
563 
564 			if (err)
565 				goto exit_f;
566 
567 			break;
568 		    }
569 
570 		case IPV6_FLOWINFO:
571 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
572 				err = -EINVAL;
573 				goto exit_f;
574 			}
575 
576 			if (fl->fl6_flowlabel&IPV6_FLOWINFO_MASK) {
577 				if ((fl->fl6_flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
578 					err = -EINVAL;
579 					goto exit_f;
580 				}
581 			}
582 			fl->fl6_flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
583 			break;
584 
585 		case IPV6_2292HOPOPTS:
586 		case IPV6_HOPOPTS:
587 			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
588 				err = -EINVAL;
589 				goto exit_f;
590 			}
591 
592 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
593 			len = ((hdr->hdrlen + 1) << 3);
594 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
595 				err = -EINVAL;
596 				goto exit_f;
597 			}
598 			if (!capable(CAP_NET_RAW)) {
599 				err = -EPERM;
600 				goto exit_f;
601 			}
602 			opt->opt_nflen += len;
603 			opt->hopopt = hdr;
604 			break;
605 
606 		case IPV6_2292DSTOPTS:
607 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
608 				err = -EINVAL;
609 				goto exit_f;
610 			}
611 
612 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
613 			len = ((hdr->hdrlen + 1) << 3);
614 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
615 				err = -EINVAL;
616 				goto exit_f;
617 			}
618 			if (!capable(CAP_NET_RAW)) {
619 				err = -EPERM;
620 				goto exit_f;
621 			}
622 			if (opt->dst1opt) {
623 				err = -EINVAL;
624 				goto exit_f;
625 			}
626 			opt->opt_flen += len;
627 			opt->dst1opt = hdr;
628 			break;
629 
630 		case IPV6_DSTOPTS:
631 		case IPV6_RTHDRDSTOPTS:
632 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
633 				err = -EINVAL;
634 				goto exit_f;
635 			}
636 
637 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
638 			len = ((hdr->hdrlen + 1) << 3);
639 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
640 				err = -EINVAL;
641 				goto exit_f;
642 			}
643 			if (!capable(CAP_NET_RAW)) {
644 				err = -EPERM;
645 				goto exit_f;
646 			}
647 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
648 				opt->opt_flen += len;
649 				opt->dst1opt = hdr;
650 			} else {
651 				opt->opt_nflen += len;
652 				opt->dst0opt = hdr;
653 			}
654 			break;
655 
656 		case IPV6_2292RTHDR:
657 		case IPV6_RTHDR:
658 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
659 				err = -EINVAL;
660 				goto exit_f;
661 			}
662 
663 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
664 
665 			switch (rthdr->type) {
666 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
667 			case IPV6_SRCRT_TYPE_2:
668 				if (rthdr->hdrlen != 2 ||
669 				    rthdr->segments_left != 1) {
670 					err = -EINVAL;
671 					goto exit_f;
672 				}
673 				break;
674 #endif
675 			default:
676 				err = -EINVAL;
677 				goto exit_f;
678 			}
679 
680 			len = ((rthdr->hdrlen + 1) << 3);
681 
682 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
683 				err = -EINVAL;
684 				goto exit_f;
685 			}
686 
687 			/* segments left must also match */
688 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
689 				err = -EINVAL;
690 				goto exit_f;
691 			}
692 
693 			opt->opt_nflen += len;
694 			opt->srcrt = rthdr;
695 
696 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
697 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
698 
699 				opt->opt_nflen += dsthdrlen;
700 				opt->dst0opt = opt->dst1opt;
701 				opt->dst1opt = NULL;
702 				opt->opt_flen -= dsthdrlen;
703 			}
704 
705 			break;
706 
707 		case IPV6_2292HOPLIMIT:
708 		case IPV6_HOPLIMIT:
709 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
710 				err = -EINVAL;
711 				goto exit_f;
712 			}
713 
714 			*hlimit = *(int *)CMSG_DATA(cmsg);
715 			if (*hlimit < -1 || *hlimit > 0xff) {
716 				err = -EINVAL;
717 				goto exit_f;
718 			}
719 
720 			break;
721 
722 		case IPV6_TCLASS:
723 		    {
724 			int tc;
725 
726 			err = -EINVAL;
727 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
728 				goto exit_f;
729 			}
730 
731 			tc = *(int *)CMSG_DATA(cmsg);
732 			if (tc < -1 || tc > 0xff)
733 				goto exit_f;
734 
735 			err = 0;
736 			*tclass = tc;
737 
738 			break;
739 		    }
740 		default:
741 			LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
742 				       cmsg->cmsg_type);
743 			err = -EINVAL;
744 			goto exit_f;
745 		}
746 	}
747 
748 exit_f:
749 	return err;
750 }
751