xref: /linux/net/ipv6/datagram.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
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 #include <linux/export.h>
26 
27 #include <net/ipv6.h>
28 #include <net/ndisc.h>
29 #include <net/addrconf.h>
30 #include <net/transp_v6.h>
31 #include <net/ip6_route.h>
32 #include <net/tcp_states.h>
33 
34 #include <linux/errqueue.h>
35 #include <asm/uaccess.h>
36 
37 static bool ipv6_mapped_addr_any(const struct in6_addr *a)
38 {
39 	return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
40 }
41 
42 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
43 {
44 	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;
45 	struct inet_sock      	*inet = inet_sk(sk);
46 	struct ipv6_pinfo      	*np = inet6_sk(sk);
47 	struct in6_addr		*daddr, *final_p, final;
48 	struct dst_entry	*dst;
49 	struct flowi6		fl6;
50 	struct ip6_flowlabel	*flowlabel = NULL;
51 	struct ipv6_txoptions   *opt;
52 	int			addr_type;
53 	int			err;
54 
55 	if (usin->sin6_family == AF_INET) {
56 		if (__ipv6_only_sock(sk))
57 			return -EAFNOSUPPORT;
58 		err = ip4_datagram_connect(sk, uaddr, addr_len);
59 		goto ipv4_connected;
60 	}
61 
62 	if (addr_len < SIN6_LEN_RFC2133)
63 		return -EINVAL;
64 
65 	if (usin->sin6_family != AF_INET6)
66 		return -EAFNOSUPPORT;
67 
68 	memset(&fl6, 0, sizeof(fl6));
69 	if (np->sndflow) {
70 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
71 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
72 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
73 			if (flowlabel == NULL)
74 				return -EINVAL;
75 			usin->sin6_addr = flowlabel->dst;
76 		}
77 	}
78 
79 	addr_type = ipv6_addr_type(&usin->sin6_addr);
80 
81 	if (addr_type == IPV6_ADDR_ANY) {
82 		/*
83 		 *	connect to self
84 		 */
85 		usin->sin6_addr.s6_addr[15] = 0x01;
86 	}
87 
88 	daddr = &usin->sin6_addr;
89 
90 	if (addr_type == IPV6_ADDR_MAPPED) {
91 		struct sockaddr_in sin;
92 
93 		if (__ipv6_only_sock(sk)) {
94 			err = -ENETUNREACH;
95 			goto out;
96 		}
97 		sin.sin_family = AF_INET;
98 		sin.sin_addr.s_addr = daddr->s6_addr32[3];
99 		sin.sin_port = usin->sin6_port;
100 
101 		err = ip4_datagram_connect(sk,
102 					   (struct sockaddr *) &sin,
103 					   sizeof(sin));
104 
105 ipv4_connected:
106 		if (err)
107 			goto out;
108 
109 		ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
110 
111 		if (ipv6_addr_any(&np->saddr) ||
112 		    ipv6_mapped_addr_any(&np->saddr))
113 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
114 
115 		if (ipv6_addr_any(&np->rcv_saddr) ||
116 		    ipv6_mapped_addr_any(&np->rcv_saddr)) {
117 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
118 					       &np->rcv_saddr);
119 			if (sk->sk_prot->rehash)
120 				sk->sk_prot->rehash(sk);
121 		}
122 
123 		goto out;
124 	}
125 
126 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
127 		if (addr_len >= sizeof(struct sockaddr_in6) &&
128 		    usin->sin6_scope_id) {
129 			if (sk->sk_bound_dev_if &&
130 			    sk->sk_bound_dev_if != usin->sin6_scope_id) {
131 				err = -EINVAL;
132 				goto out;
133 			}
134 			sk->sk_bound_dev_if = usin->sin6_scope_id;
135 		}
136 
137 		if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
138 			sk->sk_bound_dev_if = np->mcast_oif;
139 
140 		/* Connect to link-local address requires an interface */
141 		if (!sk->sk_bound_dev_if) {
142 			err = -EINVAL;
143 			goto out;
144 		}
145 	}
146 
147 	np->daddr = *daddr;
148 	np->flow_label = fl6.flowlabel;
149 
150 	inet->inet_dport = usin->sin6_port;
151 
152 	/*
153 	 *	Check for a route to destination an obtain the
154 	 *	destination cache for it.
155 	 */
156 
157 	fl6.flowi6_proto = sk->sk_protocol;
158 	fl6.daddr = np->daddr;
159 	fl6.saddr = np->saddr;
160 	fl6.flowi6_oif = sk->sk_bound_dev_if;
161 	fl6.flowi6_mark = sk->sk_mark;
162 	fl6.fl6_dport = inet->inet_dport;
163 	fl6.fl6_sport = inet->inet_sport;
164 
165 	if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
166 		fl6.flowi6_oif = np->mcast_oif;
167 
168 	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
169 
170 	opt = flowlabel ? flowlabel->opt : np->opt;
171 	final_p = fl6_update_dst(&fl6, opt, &final);
172 
173 	dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
174 	err = 0;
175 	if (IS_ERR(dst)) {
176 		err = PTR_ERR(dst);
177 		goto out;
178 	}
179 
180 	/* source address lookup done in ip6_dst_lookup */
181 
182 	if (ipv6_addr_any(&np->saddr))
183 		np->saddr = fl6.saddr;
184 
185 	if (ipv6_addr_any(&np->rcv_saddr)) {
186 		np->rcv_saddr = fl6.saddr;
187 		inet->inet_rcv_saddr = LOOPBACK4_IPV6;
188 		if (sk->sk_prot->rehash)
189 			sk->sk_prot->rehash(sk);
190 	}
191 
192 	ip6_dst_store(sk, dst,
193 		      ipv6_addr_equal(&fl6.daddr, &np->daddr) ?
194 		      &np->daddr : NULL,
195 #ifdef CONFIG_IPV6_SUBTREES
196 		      ipv6_addr_equal(&fl6.saddr, &np->saddr) ?
197 		      &np->saddr :
198 #endif
199 		      NULL);
200 
201 	sk->sk_state = TCP_ESTABLISHED;
202 out:
203 	fl6_sock_release(flowlabel);
204 	return err;
205 }
206 EXPORT_SYMBOL_GPL(ip6_datagram_connect);
207 
208 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
209 		     __be16 port, u32 info, u8 *payload)
210 {
211 	struct ipv6_pinfo *np  = inet6_sk(sk);
212 	struct icmp6hdr *icmph = icmp6_hdr(skb);
213 	struct sock_exterr_skb *serr;
214 
215 	if (!np->recverr)
216 		return;
217 
218 	skb = skb_clone(skb, GFP_ATOMIC);
219 	if (!skb)
220 		return;
221 
222 	skb->protocol = htons(ETH_P_IPV6);
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 flowi6 *fl6, 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->protocol = htons(ETH_P_IPV6);
258 
259 	skb_put(skb, sizeof(struct ipv6hdr));
260 	skb_reset_network_header(skb);
261 	iph = ipv6_hdr(skb);
262 	iph->daddr = fl6->daddr;
263 
264 	serr = SKB_EXT_ERR(skb);
265 	serr->ee.ee_errno = err;
266 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
267 	serr->ee.ee_type = 0;
268 	serr->ee.ee_code = 0;
269 	serr->ee.ee_pad = 0;
270 	serr->ee.ee_info = info;
271 	serr->ee.ee_data = 0;
272 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
273 	serr->port = fl6->fl6_dport;
274 
275 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
276 	skb_reset_transport_header(skb);
277 
278 	if (sock_queue_err_skb(sk, skb))
279 		kfree_skb(skb);
280 }
281 
282 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
283 {
284 	struct ipv6_pinfo *np = inet6_sk(sk);
285 	struct ipv6hdr *iph;
286 	struct sk_buff *skb;
287 	struct ip6_mtuinfo *mtu_info;
288 
289 	if (!np->rxopt.bits.rxpmtu)
290 		return;
291 
292 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
293 	if (!skb)
294 		return;
295 
296 	skb_put(skb, sizeof(struct ipv6hdr));
297 	skb_reset_network_header(skb);
298 	iph = ipv6_hdr(skb);
299 	iph->daddr = fl6->daddr;
300 
301 	mtu_info = IP6CBMTU(skb);
302 
303 	mtu_info->ip6m_mtu = mtu;
304 	mtu_info->ip6m_addr.sin6_family = AF_INET6;
305 	mtu_info->ip6m_addr.sin6_port = 0;
306 	mtu_info->ip6m_addr.sin6_flowinfo = 0;
307 	mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
308 	mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
309 
310 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
311 	skb_reset_transport_header(skb);
312 
313 	skb = xchg(&np->rxpmtu, skb);
314 	kfree_skb(skb);
315 }
316 
317 /*
318  *	Handle MSG_ERRQUEUE
319  */
320 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
321 {
322 	struct ipv6_pinfo *np = inet6_sk(sk);
323 	struct sock_exterr_skb *serr;
324 	struct sk_buff *skb, *skb2;
325 	struct sockaddr_in6 *sin;
326 	struct {
327 		struct sock_extended_err ee;
328 		struct sockaddr_in6	 offender;
329 	} errhdr;
330 	int err;
331 	int copied;
332 
333 	err = -EAGAIN;
334 	skb = skb_dequeue(&sk->sk_error_queue);
335 	if (skb == NULL)
336 		goto out;
337 
338 	copied = skb->len;
339 	if (copied > len) {
340 		msg->msg_flags |= MSG_TRUNC;
341 		copied = len;
342 	}
343 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
344 	if (err)
345 		goto out_free_skb;
346 
347 	sock_recv_timestamp(msg, sk, skb);
348 
349 	serr = SKB_EXT_ERR(skb);
350 
351 	sin = (struct sockaddr_in6 *)msg->msg_name;
352 	if (sin) {
353 		const unsigned char *nh = skb_network_header(skb);
354 		sin->sin6_family = AF_INET6;
355 		sin->sin6_flowinfo = 0;
356 		sin->sin6_port = serr->port;
357 		sin->sin6_scope_id = 0;
358 		if (skb->protocol == htons(ETH_P_IPV6)) {
359 			sin->sin6_addr =
360 				*(struct in6_addr *)(nh + serr->addr_offset);
361 			if (np->sndflow)
362 				sin->sin6_flowinfo =
363 					(*(__be32 *)(nh + serr->addr_offset - 24) &
364 					 IPV6_FLOWINFO_MASK);
365 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
366 				sin->sin6_scope_id = IP6CB(skb)->iif;
367 		} else {
368 			ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
369 					       &sin->sin6_addr);
370 		}
371 	}
372 
373 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
374 	sin = &errhdr.offender;
375 	sin->sin6_family = AF_UNSPEC;
376 	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
377 		sin->sin6_family = AF_INET6;
378 		sin->sin6_flowinfo = 0;
379 		sin->sin6_scope_id = 0;
380 		if (skb->protocol == htons(ETH_P_IPV6)) {
381 			sin->sin6_addr = ipv6_hdr(skb)->saddr;
382 			if (np->rxopt.all)
383 				datagram_recv_ctl(sk, msg, skb);
384 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
385 				sin->sin6_scope_id = IP6CB(skb)->iif;
386 		} else {
387 			struct inet_sock *inet = inet_sk(sk);
388 
389 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
390 					       &sin->sin6_addr);
391 			if (inet->cmsg_flags)
392 				ip_cmsg_recv(msg, skb);
393 		}
394 	}
395 
396 	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
397 
398 	/* Now we could try to dump offended packet options */
399 
400 	msg->msg_flags |= MSG_ERRQUEUE;
401 	err = copied;
402 
403 	/* Reset and regenerate socket error */
404 	spin_lock_bh(&sk->sk_error_queue.lock);
405 	sk->sk_err = 0;
406 	if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
407 		sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
408 		spin_unlock_bh(&sk->sk_error_queue.lock);
409 		sk->sk_error_report(sk);
410 	} else {
411 		spin_unlock_bh(&sk->sk_error_queue.lock);
412 	}
413 
414 out_free_skb:
415 	kfree_skb(skb);
416 out:
417 	return err;
418 }
419 EXPORT_SYMBOL_GPL(ipv6_recv_error);
420 
421 /*
422  *	Handle IPV6_RECVPATHMTU
423  */
424 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
425 {
426 	struct ipv6_pinfo *np = inet6_sk(sk);
427 	struct sk_buff *skb;
428 	struct sockaddr_in6 *sin;
429 	struct ip6_mtuinfo mtu_info;
430 	int err;
431 	int copied;
432 
433 	err = -EAGAIN;
434 	skb = xchg(&np->rxpmtu, NULL);
435 	if (skb == NULL)
436 		goto out;
437 
438 	copied = skb->len;
439 	if (copied > len) {
440 		msg->msg_flags |= MSG_TRUNC;
441 		copied = len;
442 	}
443 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
444 	if (err)
445 		goto out_free_skb;
446 
447 	sock_recv_timestamp(msg, sk, skb);
448 
449 	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
450 
451 	sin = (struct sockaddr_in6 *)msg->msg_name;
452 	if (sin) {
453 		sin->sin6_family = AF_INET6;
454 		sin->sin6_flowinfo = 0;
455 		sin->sin6_port = 0;
456 		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
457 		sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
458 	}
459 
460 	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
461 
462 	err = copied;
463 
464 out_free_skb:
465 	kfree_skb(skb);
466 out:
467 	return err;
468 }
469 
470 
471 int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
472 {
473 	struct ipv6_pinfo *np = inet6_sk(sk);
474 	struct inet6_skb_parm *opt = IP6CB(skb);
475 	unsigned char *nh = skb_network_header(skb);
476 
477 	if (np->rxopt.bits.rxinfo) {
478 		struct in6_pktinfo src_info;
479 
480 		src_info.ipi6_ifindex = opt->iif;
481 		src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
482 		put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
483 	}
484 
485 	if (np->rxopt.bits.rxhlim) {
486 		int hlim = ipv6_hdr(skb)->hop_limit;
487 		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
488 	}
489 
490 	if (np->rxopt.bits.rxtclass) {
491 		int tclass = ipv6_tclass(ipv6_hdr(skb));
492 		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
493 	}
494 
495 	if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
496 		__be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
497 		put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
498 	}
499 
500 	/* HbH is allowed only once */
501 	if (np->rxopt.bits.hopopts && opt->hop) {
502 		u8 *ptr = nh + opt->hop;
503 		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
504 	}
505 
506 	if (opt->lastopt &&
507 	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
508 		/*
509 		 * Silly enough, but we need to reparse in order to
510 		 * report extension headers (except for HbH)
511 		 * in order.
512 		 *
513 		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
514 		 * (and WILL NOT be) defined because
515 		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
516 		 */
517 		unsigned int off = sizeof(struct ipv6hdr);
518 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
519 
520 		while (off <= opt->lastopt) {
521 			unsigned int len;
522 			u8 *ptr = nh + off;
523 
524 			switch (nexthdr) {
525 			case IPPROTO_DSTOPTS:
526 				nexthdr = ptr[0];
527 				len = (ptr[1] + 1) << 3;
528 				if (np->rxopt.bits.dstopts)
529 					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
530 				break;
531 			case IPPROTO_ROUTING:
532 				nexthdr = ptr[0];
533 				len = (ptr[1] + 1) << 3;
534 				if (np->rxopt.bits.srcrt)
535 					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
536 				break;
537 			case IPPROTO_AH:
538 				nexthdr = ptr[0];
539 				len = (ptr[1] + 2) << 2;
540 				break;
541 			default:
542 				nexthdr = ptr[0];
543 				len = (ptr[1] + 1) << 3;
544 				break;
545 			}
546 
547 			off += len;
548 		}
549 	}
550 
551 	/* socket options in old style */
552 	if (np->rxopt.bits.rxoinfo) {
553 		struct in6_pktinfo src_info;
554 
555 		src_info.ipi6_ifindex = opt->iif;
556 		src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
557 		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
558 	}
559 	if (np->rxopt.bits.rxohlim) {
560 		int hlim = ipv6_hdr(skb)->hop_limit;
561 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
562 	}
563 	if (np->rxopt.bits.ohopopts && opt->hop) {
564 		u8 *ptr = nh + opt->hop;
565 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
566 	}
567 	if (np->rxopt.bits.odstopts && opt->dst0) {
568 		u8 *ptr = nh + opt->dst0;
569 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
570 	}
571 	if (np->rxopt.bits.osrcrt && opt->srcrt) {
572 		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
573 		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
574 	}
575 	if (np->rxopt.bits.odstopts && opt->dst1) {
576 		u8 *ptr = nh + opt->dst1;
577 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
578 	}
579 	if (np->rxopt.bits.rxorigdstaddr) {
580 		struct sockaddr_in6 sin6;
581 		__be16 *ports = (__be16 *) skb_transport_header(skb);
582 
583 		if (skb_transport_offset(skb) + 4 <= skb->len) {
584 			/* All current transport protocols have the port numbers in the
585 			 * first four bytes of the transport header and this function is
586 			 * written with this assumption in mind.
587 			 */
588 
589 			sin6.sin6_family = AF_INET6;
590 			sin6.sin6_addr = ipv6_hdr(skb)->daddr;
591 			sin6.sin6_port = ports[1];
592 			sin6.sin6_flowinfo = 0;
593 			sin6.sin6_scope_id = 0;
594 
595 			put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
596 		}
597 	}
598 	return 0;
599 }
600 
601 int datagram_send_ctl(struct net *net, struct sock *sk,
602 		      struct msghdr *msg, struct flowi6 *fl6,
603 		      struct ipv6_txoptions *opt,
604 		      int *hlimit, int *tclass, int *dontfrag)
605 {
606 	struct in6_pktinfo *src_info;
607 	struct cmsghdr *cmsg;
608 	struct ipv6_rt_hdr *rthdr;
609 	struct ipv6_opt_hdr *hdr;
610 	int len;
611 	int err = 0;
612 
613 	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
614 		int addr_type;
615 
616 		if (!CMSG_OK(msg, cmsg)) {
617 			err = -EINVAL;
618 			goto exit_f;
619 		}
620 
621 		if (cmsg->cmsg_level != SOL_IPV6)
622 			continue;
623 
624 		switch (cmsg->cmsg_type) {
625 		case IPV6_PKTINFO:
626 		case IPV6_2292PKTINFO:
627 		    {
628 			struct net_device *dev = NULL;
629 
630 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
631 				err = -EINVAL;
632 				goto exit_f;
633 			}
634 
635 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
636 
637 			if (src_info->ipi6_ifindex) {
638 				if (fl6->flowi6_oif &&
639 				    src_info->ipi6_ifindex != fl6->flowi6_oif)
640 					return -EINVAL;
641 				fl6->flowi6_oif = src_info->ipi6_ifindex;
642 			}
643 
644 			addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
645 
646 			rcu_read_lock();
647 			if (fl6->flowi6_oif) {
648 				dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
649 				if (!dev) {
650 					rcu_read_unlock();
651 					return -ENODEV;
652 				}
653 			} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
654 				rcu_read_unlock();
655 				return -EINVAL;
656 			}
657 
658 			if (addr_type != IPV6_ADDR_ANY) {
659 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
660 				if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
661 				    !ipv6_chk_addr(net, &src_info->ipi6_addr,
662 						   strict ? dev : NULL, 0))
663 					err = -EINVAL;
664 				else
665 					fl6->saddr = src_info->ipi6_addr;
666 			}
667 
668 			rcu_read_unlock();
669 
670 			if (err)
671 				goto exit_f;
672 
673 			break;
674 		    }
675 
676 		case IPV6_FLOWINFO:
677 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
678 				err = -EINVAL;
679 				goto exit_f;
680 			}
681 
682 			if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
683 				if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
684 					err = -EINVAL;
685 					goto exit_f;
686 				}
687 			}
688 			fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
689 			break;
690 
691 		case IPV6_2292HOPOPTS:
692 		case IPV6_HOPOPTS:
693 			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
694 				err = -EINVAL;
695 				goto exit_f;
696 			}
697 
698 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
699 			len = ((hdr->hdrlen + 1) << 3);
700 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
701 				err = -EINVAL;
702 				goto exit_f;
703 			}
704 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
705 				err = -EPERM;
706 				goto exit_f;
707 			}
708 			opt->opt_nflen += len;
709 			opt->hopopt = hdr;
710 			break;
711 
712 		case IPV6_2292DSTOPTS:
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 (!ns_capable(net->user_ns, CAP_NET_RAW)) {
725 				err = -EPERM;
726 				goto exit_f;
727 			}
728 			if (opt->dst1opt) {
729 				err = -EINVAL;
730 				goto exit_f;
731 			}
732 			opt->opt_flen += len;
733 			opt->dst1opt = hdr;
734 			break;
735 
736 		case IPV6_DSTOPTS:
737 		case IPV6_RTHDRDSTOPTS:
738 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
739 				err = -EINVAL;
740 				goto exit_f;
741 			}
742 
743 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
744 			len = ((hdr->hdrlen + 1) << 3);
745 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
746 				err = -EINVAL;
747 				goto exit_f;
748 			}
749 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
750 				err = -EPERM;
751 				goto exit_f;
752 			}
753 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
754 				opt->opt_flen += len;
755 				opt->dst1opt = hdr;
756 			} else {
757 				opt->opt_nflen += len;
758 				opt->dst0opt = hdr;
759 			}
760 			break;
761 
762 		case IPV6_2292RTHDR:
763 		case IPV6_RTHDR:
764 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
765 				err = -EINVAL;
766 				goto exit_f;
767 			}
768 
769 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
770 
771 			switch (rthdr->type) {
772 #if IS_ENABLED(CONFIG_IPV6_MIP6)
773 			case IPV6_SRCRT_TYPE_2:
774 				if (rthdr->hdrlen != 2 ||
775 				    rthdr->segments_left != 1) {
776 					err = -EINVAL;
777 					goto exit_f;
778 				}
779 				break;
780 #endif
781 			default:
782 				err = -EINVAL;
783 				goto exit_f;
784 			}
785 
786 			len = ((rthdr->hdrlen + 1) << 3);
787 
788 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
789 				err = -EINVAL;
790 				goto exit_f;
791 			}
792 
793 			/* segments left must also match */
794 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
795 				err = -EINVAL;
796 				goto exit_f;
797 			}
798 
799 			opt->opt_nflen += len;
800 			opt->srcrt = rthdr;
801 
802 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
803 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
804 
805 				opt->opt_nflen += dsthdrlen;
806 				opt->dst0opt = opt->dst1opt;
807 				opt->dst1opt = NULL;
808 				opt->opt_flen -= dsthdrlen;
809 			}
810 
811 			break;
812 
813 		case IPV6_2292HOPLIMIT:
814 		case IPV6_HOPLIMIT:
815 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
816 				err = -EINVAL;
817 				goto exit_f;
818 			}
819 
820 			*hlimit = *(int *)CMSG_DATA(cmsg);
821 			if (*hlimit < -1 || *hlimit > 0xff) {
822 				err = -EINVAL;
823 				goto exit_f;
824 			}
825 
826 			break;
827 
828 		case IPV6_TCLASS:
829 		    {
830 			int tc;
831 
832 			err = -EINVAL;
833 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
834 				goto exit_f;
835 
836 			tc = *(int *)CMSG_DATA(cmsg);
837 			if (tc < -1 || tc > 0xff)
838 				goto exit_f;
839 
840 			err = 0;
841 			*tclass = tc;
842 
843 			break;
844 		    }
845 
846 		case IPV6_DONTFRAG:
847 		    {
848 			int df;
849 
850 			err = -EINVAL;
851 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
852 				goto exit_f;
853 
854 			df = *(int *)CMSG_DATA(cmsg);
855 			if (df < 0 || df > 1)
856 				goto exit_f;
857 
858 			err = 0;
859 			*dontfrag = df;
860 
861 			break;
862 		    }
863 		default:
864 			LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
865 				       cmsg->cmsg_type);
866 			err = -EINVAL;
867 			goto exit_f;
868 		}
869 	}
870 
871 exit_f:
872 	return err;
873 }
874 EXPORT_SYMBOL_GPL(datagram_send_ctl);
875