xref: /linux/net/ipv6/datagram.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
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, final;
42 	struct dst_entry	*dst;
43 	struct flowi		fl;
44 	struct ip6_flowlabel	*flowlabel = NULL;
45 	struct ipv6_txoptions   *opt;
46 	int			addr_type;
47 	int			err;
48 
49 	if (usin->sin6_family == AF_INET) {
50 		if (__ipv6_only_sock(sk))
51 			return -EAFNOSUPPORT;
52 		err = ip4_datagram_connect(sk, uaddr, addr_len);
53 		goto ipv4_connected;
54 	}
55 
56 	if (addr_len < SIN6_LEN_RFC2133)
57 		return -EINVAL;
58 
59 	if (usin->sin6_family != AF_INET6)
60 		return -EAFNOSUPPORT;
61 
62 	memset(&fl, 0, sizeof(fl));
63 	if (np->sndflow) {
64 		fl.fl6_flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
65 		if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
66 			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
67 			if (flowlabel == NULL)
68 				return -EINVAL;
69 			ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
70 		}
71 	}
72 
73 	addr_type = ipv6_addr_type(&usin->sin6_addr);
74 
75 	if (addr_type == IPV6_ADDR_ANY) {
76 		/*
77 		 *	connect to self
78 		 */
79 		usin->sin6_addr.s6_addr[15] = 0x01;
80 	}
81 
82 	daddr = &usin->sin6_addr;
83 
84 	if (addr_type == IPV6_ADDR_MAPPED) {
85 		struct sockaddr_in sin;
86 
87 		if (__ipv6_only_sock(sk)) {
88 			err = -ENETUNREACH;
89 			goto out;
90 		}
91 		sin.sin_family = AF_INET;
92 		sin.sin_addr.s_addr = daddr->s6_addr32[3];
93 		sin.sin_port = usin->sin6_port;
94 
95 		err = ip4_datagram_connect(sk,
96 					   (struct sockaddr*) &sin,
97 					   sizeof(sin));
98 
99 ipv4_connected:
100 		if (err)
101 			goto out;
102 
103 		ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
104 
105 		if (ipv6_addr_any(&np->saddr))
106 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
107 
108 		if (ipv6_addr_any(&np->rcv_saddr))
109 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
110 					       &np->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->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.mark = sk->sk_mark;
151 	fl.fl_ip_dport = inet->inet_dport;
152 	fl.fl_ip_sport = inet->inet_sport;
153 
154 	if (!fl.oif && (addr_type&IPV6_ADDR_MULTICAST))
155 		fl.oif = np->mcast_oif;
156 
157 	security_sk_classify_flow(sk, &fl);
158 
159 	opt = flowlabel ? flowlabel->opt : np->opt;
160 	final_p = fl6_update_dst(&fl, opt, &final);
161 
162 	err = ip6_dst_lookup(sk, &dst, &fl);
163 	if (err)
164 		goto out;
165 	if (final_p)
166 		ipv6_addr_copy(&fl.fl6_dst, final_p);
167 
168 	err = __xfrm_lookup(sock_net(sk), &dst, &fl, sk, XFRM_LOOKUP_WAIT);
169 	if (err < 0) {
170 		if (err == -EREMOTE)
171 			err = ip6_dst_blackhole(sk, &dst, &fl);
172 		if (err < 0)
173 			goto out;
174 	}
175 
176 	/* source address lookup done in ip6_dst_lookup */
177 
178 	if (ipv6_addr_any(&np->saddr))
179 		ipv6_addr_copy(&np->saddr, &fl.fl6_src);
180 
181 	if (ipv6_addr_any(&np->rcv_saddr)) {
182 		ipv6_addr_copy(&np->rcv_saddr, &fl.fl6_src);
183 		inet->inet_rcv_saddr = LOOPBACK4_IPV6;
184 	}
185 
186 	ip6_dst_store(sk, dst,
187 		      ipv6_addr_equal(&fl.fl6_dst, &np->daddr) ?
188 		      &np->daddr : NULL,
189 #ifdef CONFIG_IPV6_SUBTREES
190 		      ipv6_addr_equal(&fl.fl6_src, &np->saddr) ?
191 		      &np->saddr :
192 #endif
193 		      NULL);
194 
195 	sk->sk_state = TCP_ESTABLISHED;
196 out:
197 	fl6_sock_release(flowlabel);
198 	return err;
199 }
200 
201 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
202 		     __be16 port, u32 info, u8 *payload)
203 {
204 	struct ipv6_pinfo *np  = inet6_sk(sk);
205 	struct icmp6hdr *icmph = icmp6_hdr(skb);
206 	struct sock_exterr_skb *serr;
207 
208 	if (!np->recverr)
209 		return;
210 
211 	skb = skb_clone(skb, GFP_ATOMIC);
212 	if (!skb)
213 		return;
214 
215 	skb->protocol = htons(ETH_P_IPV6);
216 
217 	serr = SKB_EXT_ERR(skb);
218 	serr->ee.ee_errno = err;
219 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
220 	serr->ee.ee_type = icmph->icmp6_type;
221 	serr->ee.ee_code = icmph->icmp6_code;
222 	serr->ee.ee_pad = 0;
223 	serr->ee.ee_info = info;
224 	serr->ee.ee_data = 0;
225 	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
226 				  skb_network_header(skb);
227 	serr->port = port;
228 
229 	__skb_pull(skb, payload - skb->data);
230 	skb_reset_transport_header(skb);
231 
232 	if (sock_queue_err_skb(sk, skb))
233 		kfree_skb(skb);
234 }
235 
236 void ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info)
237 {
238 	struct ipv6_pinfo *np = inet6_sk(sk);
239 	struct sock_exterr_skb *serr;
240 	struct ipv6hdr *iph;
241 	struct sk_buff *skb;
242 
243 	if (!np->recverr)
244 		return;
245 
246 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
247 	if (!skb)
248 		return;
249 
250 	skb->protocol = htons(ETH_P_IPV6);
251 
252 	skb_put(skb, sizeof(struct ipv6hdr));
253 	skb_reset_network_header(skb);
254 	iph = ipv6_hdr(skb);
255 	ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);
256 
257 	serr = SKB_EXT_ERR(skb);
258 	serr->ee.ee_errno = err;
259 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
260 	serr->ee.ee_type = 0;
261 	serr->ee.ee_code = 0;
262 	serr->ee.ee_pad = 0;
263 	serr->ee.ee_info = info;
264 	serr->ee.ee_data = 0;
265 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
266 	serr->port = fl->fl_ip_dport;
267 
268 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
269 	skb_reset_transport_header(skb);
270 
271 	if (sock_queue_err_skb(sk, skb))
272 		kfree_skb(skb);
273 }
274 
275 void ipv6_local_rxpmtu(struct sock *sk, struct flowi *fl, u32 mtu)
276 {
277 	struct ipv6_pinfo *np = inet6_sk(sk);
278 	struct ipv6hdr *iph;
279 	struct sk_buff *skb;
280 	struct ip6_mtuinfo *mtu_info;
281 
282 	if (!np->rxopt.bits.rxpmtu)
283 		return;
284 
285 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
286 	if (!skb)
287 		return;
288 
289 	skb_put(skb, sizeof(struct ipv6hdr));
290 	skb_reset_network_header(skb);
291 	iph = ipv6_hdr(skb);
292 	ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);
293 
294 	mtu_info = IP6CBMTU(skb);
295 	if (!mtu_info) {
296 		kfree_skb(skb);
297 		return;
298 	}
299 
300 	mtu_info->ip6m_mtu = mtu;
301 	mtu_info->ip6m_addr.sin6_family = AF_INET6;
302 	mtu_info->ip6m_addr.sin6_port = 0;
303 	mtu_info->ip6m_addr.sin6_flowinfo = 0;
304 	mtu_info->ip6m_addr.sin6_scope_id = fl->oif;
305 	ipv6_addr_copy(&mtu_info->ip6m_addr.sin6_addr, &ipv6_hdr(skb)->daddr);
306 
307 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
308 	skb_reset_transport_header(skb);
309 
310 	skb = xchg(&np->rxpmtu, skb);
311 	kfree_skb(skb);
312 }
313 
314 /*
315  *	Handle MSG_ERRQUEUE
316  */
317 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
318 {
319 	struct ipv6_pinfo *np = inet6_sk(sk);
320 	struct sock_exterr_skb *serr;
321 	struct sk_buff *skb, *skb2;
322 	struct sockaddr_in6 *sin;
323 	struct {
324 		struct sock_extended_err ee;
325 		struct sockaddr_in6	 offender;
326 	} errhdr;
327 	int err;
328 	int copied;
329 
330 	err = -EAGAIN;
331 	skb = skb_dequeue(&sk->sk_error_queue);
332 	if (skb == NULL)
333 		goto out;
334 
335 	copied = skb->len;
336 	if (copied > len) {
337 		msg->msg_flags |= MSG_TRUNC;
338 		copied = len;
339 	}
340 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
341 	if (err)
342 		goto out_free_skb;
343 
344 	sock_recv_timestamp(msg, sk, skb);
345 
346 	serr = SKB_EXT_ERR(skb);
347 
348 	sin = (struct sockaddr_in6 *)msg->msg_name;
349 	if (sin) {
350 		const unsigned char *nh = skb_network_header(skb);
351 		sin->sin6_family = AF_INET6;
352 		sin->sin6_flowinfo = 0;
353 		sin->sin6_port = serr->port;
354 		sin->sin6_scope_id = 0;
355 		if (skb->protocol == htons(ETH_P_IPV6)) {
356 			ipv6_addr_copy(&sin->sin6_addr,
357 				  (struct in6_addr *)(nh + serr->addr_offset));
358 			if (np->sndflow)
359 				sin->sin6_flowinfo =
360 					(*(__be32 *)(nh + serr->addr_offset - 24) &
361 					 IPV6_FLOWINFO_MASK);
362 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
363 				sin->sin6_scope_id = IP6CB(skb)->iif;
364 		} else {
365 			ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
366 					       &sin->sin6_addr);
367 		}
368 	}
369 
370 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
371 	sin = &errhdr.offender;
372 	sin->sin6_family = AF_UNSPEC;
373 	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
374 		sin->sin6_family = AF_INET6;
375 		sin->sin6_flowinfo = 0;
376 		sin->sin6_scope_id = 0;
377 		if (skb->protocol == htons(ETH_P_IPV6)) {
378 			ipv6_addr_copy(&sin->sin6_addr, &ipv6_hdr(skb)->saddr);
379 			if (np->rxopt.all)
380 				datagram_recv_ctl(sk, msg, skb);
381 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
382 				sin->sin6_scope_id = IP6CB(skb)->iif;
383 		} else {
384 			struct inet_sock *inet = inet_sk(sk);
385 
386 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
387 					       &sin->sin6_addr);
388 			if (inet->cmsg_flags)
389 				ip_cmsg_recv(msg, skb);
390 		}
391 	}
392 
393 	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
394 
395 	/* Now we could try to dump offended packet options */
396 
397 	msg->msg_flags |= MSG_ERRQUEUE;
398 	err = copied;
399 
400 	/* Reset and regenerate socket error */
401 	spin_lock_bh(&sk->sk_error_queue.lock);
402 	sk->sk_err = 0;
403 	if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
404 		sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
405 		spin_unlock_bh(&sk->sk_error_queue.lock);
406 		sk->sk_error_report(sk);
407 	} else {
408 		spin_unlock_bh(&sk->sk_error_queue.lock);
409 	}
410 
411 out_free_skb:
412 	kfree_skb(skb);
413 out:
414 	return err;
415 }
416 
417 /*
418  *	Handle IPV6_RECVPATHMTU
419  */
420 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
421 {
422 	struct ipv6_pinfo *np = inet6_sk(sk);
423 	struct sk_buff *skb;
424 	struct sockaddr_in6 *sin;
425 	struct ip6_mtuinfo mtu_info;
426 	int err;
427 	int copied;
428 
429 	err = -EAGAIN;
430 	skb = xchg(&np->rxpmtu, NULL);
431 	if (skb == NULL)
432 		goto out;
433 
434 	copied = skb->len;
435 	if (copied > len) {
436 		msg->msg_flags |= MSG_TRUNC;
437 		copied = len;
438 	}
439 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
440 	if (err)
441 		goto out_free_skb;
442 
443 	sock_recv_timestamp(msg, sk, skb);
444 
445 	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
446 
447 	sin = (struct sockaddr_in6 *)msg->msg_name;
448 	if (sin) {
449 		sin->sin6_family = AF_INET6;
450 		sin->sin6_flowinfo = 0;
451 		sin->sin6_port = 0;
452 		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
453 		ipv6_addr_copy(&sin->sin6_addr, &mtu_info.ip6m_addr.sin6_addr);
454 	}
455 
456 	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
457 
458 	err = copied;
459 
460 out_free_skb:
461 	kfree_skb(skb);
462 out:
463 	return err;
464 }
465 
466 
467 int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
468 {
469 	struct ipv6_pinfo *np = inet6_sk(sk);
470 	struct inet6_skb_parm *opt = IP6CB(skb);
471 	unsigned char *nh = skb_network_header(skb);
472 
473 	if (np->rxopt.bits.rxinfo) {
474 		struct in6_pktinfo src_info;
475 
476 		src_info.ipi6_ifindex = opt->iif;
477 		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
478 		put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
479 	}
480 
481 	if (np->rxopt.bits.rxhlim) {
482 		int hlim = ipv6_hdr(skb)->hop_limit;
483 		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
484 	}
485 
486 	if (np->rxopt.bits.rxtclass) {
487 		int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
488 		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
489 	}
490 
491 	if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
492 		__be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
493 		put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
494 	}
495 
496 	/* HbH is allowed only once */
497 	if (np->rxopt.bits.hopopts && opt->hop) {
498 		u8 *ptr = nh + opt->hop;
499 		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
500 	}
501 
502 	if (opt->lastopt &&
503 	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
504 		/*
505 		 * Silly enough, but we need to reparse in order to
506 		 * report extension headers (except for HbH)
507 		 * in order.
508 		 *
509 		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
510 		 * (and WILL NOT be) defined because
511 		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
512 		 */
513 		unsigned int off = sizeof(struct ipv6hdr);
514 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
515 
516 		while (off <= opt->lastopt) {
517 			unsigned len;
518 			u8 *ptr = nh + off;
519 
520 			switch(nexthdr) {
521 			case IPPROTO_DSTOPTS:
522 				nexthdr = ptr[0];
523 				len = (ptr[1] + 1) << 3;
524 				if (np->rxopt.bits.dstopts)
525 					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
526 				break;
527 			case IPPROTO_ROUTING:
528 				nexthdr = ptr[0];
529 				len = (ptr[1] + 1) << 3;
530 				if (np->rxopt.bits.srcrt)
531 					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
532 				break;
533 			case IPPROTO_AH:
534 				nexthdr = ptr[0];
535 				len = (ptr[1] + 2) << 2;
536 				break;
537 			default:
538 				nexthdr = ptr[0];
539 				len = (ptr[1] + 1) << 3;
540 				break;
541 			}
542 
543 			off += len;
544 		}
545 	}
546 
547 	/* socket options in old style */
548 	if (np->rxopt.bits.rxoinfo) {
549 		struct in6_pktinfo src_info;
550 
551 		src_info.ipi6_ifindex = opt->iif;
552 		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
553 		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
554 	}
555 	if (np->rxopt.bits.rxohlim) {
556 		int hlim = ipv6_hdr(skb)->hop_limit;
557 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
558 	}
559 	if (np->rxopt.bits.ohopopts && opt->hop) {
560 		u8 *ptr = nh + opt->hop;
561 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
562 	}
563 	if (np->rxopt.bits.odstopts && opt->dst0) {
564 		u8 *ptr = nh + opt->dst0;
565 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
566 	}
567 	if (np->rxopt.bits.osrcrt && opt->srcrt) {
568 		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
569 		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
570 	}
571 	if (np->rxopt.bits.odstopts && opt->dst1) {
572 		u8 *ptr = nh + opt->dst1;
573 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
574 	}
575 	return 0;
576 }
577 
578 int datagram_send_ctl(struct net *net,
579 		      struct msghdr *msg, struct flowi *fl,
580 		      struct ipv6_txoptions *opt,
581 		      int *hlimit, int *tclass, int *dontfrag)
582 {
583 	struct in6_pktinfo *src_info;
584 	struct cmsghdr *cmsg;
585 	struct ipv6_rt_hdr *rthdr;
586 	struct ipv6_opt_hdr *hdr;
587 	int len;
588 	int err = 0;
589 
590 	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
591 		int addr_type;
592 
593 		if (!CMSG_OK(msg, cmsg)) {
594 			err = -EINVAL;
595 			goto exit_f;
596 		}
597 
598 		if (cmsg->cmsg_level != SOL_IPV6)
599 			continue;
600 
601 		switch (cmsg->cmsg_type) {
602 		case IPV6_PKTINFO:
603 		case IPV6_2292PKTINFO:
604 		    {
605 			struct net_device *dev = NULL;
606 
607 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
608 				err = -EINVAL;
609 				goto exit_f;
610 			}
611 
612 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
613 
614 			if (src_info->ipi6_ifindex) {
615 				if (fl->oif && src_info->ipi6_ifindex != fl->oif)
616 					return -EINVAL;
617 				fl->oif = src_info->ipi6_ifindex;
618 			}
619 
620 			addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
621 
622 			rcu_read_lock();
623 			if (fl->oif) {
624 				dev = dev_get_by_index_rcu(net, fl->oif);
625 				if (!dev) {
626 					rcu_read_unlock();
627 					return -ENODEV;
628 				}
629 			} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
630 				rcu_read_unlock();
631 				return -EINVAL;
632 			}
633 
634 			if (addr_type != IPV6_ADDR_ANY) {
635 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
636 				if (!ipv6_chk_addr(net, &src_info->ipi6_addr,
637 						   strict ? dev : NULL, 0))
638 					err = -EINVAL;
639 				else
640 					ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
641 			}
642 
643 			rcu_read_unlock();
644 
645 			if (err)
646 				goto exit_f;
647 
648 			break;
649 		    }
650 
651 		case IPV6_FLOWINFO:
652 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
653 				err = -EINVAL;
654 				goto exit_f;
655 			}
656 
657 			if (fl->fl6_flowlabel&IPV6_FLOWINFO_MASK) {
658 				if ((fl->fl6_flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
659 					err = -EINVAL;
660 					goto exit_f;
661 				}
662 			}
663 			fl->fl6_flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
664 			break;
665 
666 		case IPV6_2292HOPOPTS:
667 		case IPV6_HOPOPTS:
668 			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
669 				err = -EINVAL;
670 				goto exit_f;
671 			}
672 
673 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
674 			len = ((hdr->hdrlen + 1) << 3);
675 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
676 				err = -EINVAL;
677 				goto exit_f;
678 			}
679 			if (!capable(CAP_NET_RAW)) {
680 				err = -EPERM;
681 				goto exit_f;
682 			}
683 			opt->opt_nflen += len;
684 			opt->hopopt = hdr;
685 			break;
686 
687 		case IPV6_2292DSTOPTS:
688 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
689 				err = -EINVAL;
690 				goto exit_f;
691 			}
692 
693 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
694 			len = ((hdr->hdrlen + 1) << 3);
695 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
696 				err = -EINVAL;
697 				goto exit_f;
698 			}
699 			if (!capable(CAP_NET_RAW)) {
700 				err = -EPERM;
701 				goto exit_f;
702 			}
703 			if (opt->dst1opt) {
704 				err = -EINVAL;
705 				goto exit_f;
706 			}
707 			opt->opt_flen += len;
708 			opt->dst1opt = hdr;
709 			break;
710 
711 		case IPV6_DSTOPTS:
712 		case IPV6_RTHDRDSTOPTS:
713 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
714 				err = -EINVAL;
715 				goto exit_f;
716 			}
717 
718 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
719 			len = ((hdr->hdrlen + 1) << 3);
720 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
721 				err = -EINVAL;
722 				goto exit_f;
723 			}
724 			if (!capable(CAP_NET_RAW)) {
725 				err = -EPERM;
726 				goto exit_f;
727 			}
728 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
729 				opt->opt_flen += len;
730 				opt->dst1opt = hdr;
731 			} else {
732 				opt->opt_nflen += len;
733 				opt->dst0opt = hdr;
734 			}
735 			break;
736 
737 		case IPV6_2292RTHDR:
738 		case IPV6_RTHDR:
739 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
740 				err = -EINVAL;
741 				goto exit_f;
742 			}
743 
744 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
745 
746 			switch (rthdr->type) {
747 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
748 			case IPV6_SRCRT_TYPE_2:
749 				if (rthdr->hdrlen != 2 ||
750 				    rthdr->segments_left != 1) {
751 					err = -EINVAL;
752 					goto exit_f;
753 				}
754 				break;
755 #endif
756 			default:
757 				err = -EINVAL;
758 				goto exit_f;
759 			}
760 
761 			len = ((rthdr->hdrlen + 1) << 3);
762 
763 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
764 				err = -EINVAL;
765 				goto exit_f;
766 			}
767 
768 			/* segments left must also match */
769 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
770 				err = -EINVAL;
771 				goto exit_f;
772 			}
773 
774 			opt->opt_nflen += len;
775 			opt->srcrt = rthdr;
776 
777 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
778 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
779 
780 				opt->opt_nflen += dsthdrlen;
781 				opt->dst0opt = opt->dst1opt;
782 				opt->dst1opt = NULL;
783 				opt->opt_flen -= dsthdrlen;
784 			}
785 
786 			break;
787 
788 		case IPV6_2292HOPLIMIT:
789 		case IPV6_HOPLIMIT:
790 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
791 				err = -EINVAL;
792 				goto exit_f;
793 			}
794 
795 			*hlimit = *(int *)CMSG_DATA(cmsg);
796 			if (*hlimit < -1 || *hlimit > 0xff) {
797 				err = -EINVAL;
798 				goto exit_f;
799 			}
800 
801 			break;
802 
803 		case IPV6_TCLASS:
804 		    {
805 			int tc;
806 
807 			err = -EINVAL;
808 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
809 				goto exit_f;
810 			}
811 
812 			tc = *(int *)CMSG_DATA(cmsg);
813 			if (tc < -1 || tc > 0xff)
814 				goto exit_f;
815 
816 			err = 0;
817 			*tclass = tc;
818 
819 			break;
820 		    }
821 
822 		case IPV6_DONTFRAG:
823 		    {
824 			int df;
825 
826 			err = -EINVAL;
827 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
828 				goto exit_f;
829 			}
830 
831 			df = *(int *)CMSG_DATA(cmsg);
832 			if (df < 0 || df > 1)
833 				goto exit_f;
834 
835 			err = 0;
836 			*dontfrag = df;
837 
838 			break;
839 		    }
840 		default:
841 			LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
842 				       cmsg->cmsg_type);
843 			err = -EINVAL;
844 			goto exit_f;
845 		}
846 	}
847 
848 exit_f:
849 	return err;
850 }
851