xref: /openbmc/linux/net/ipv6/datagram.c (revision 976fa9a3)
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 #include <net/dsfield.h>
34 
35 #include <linux/errqueue.h>
36 #include <asm/uaccess.h>
37 
38 static bool ipv6_mapped_addr_any(const struct in6_addr *a)
39 {
40 	return ipv6_addr_v4mapped(a) && (a->s6_addr32[3] == 0);
41 }
42 
43 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
44 {
45 	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;
46 	struct inet_sock	*inet = inet_sk(sk);
47 	struct ipv6_pinfo	*np = inet6_sk(sk);
48 	struct in6_addr	*daddr, *final_p, final;
49 	struct dst_entry	*dst;
50 	struct flowi6		fl6;
51 	struct ip6_flowlabel	*flowlabel = NULL;
52 	struct ipv6_txoptions	*opt;
53 	int			addr_type;
54 	int			err;
55 
56 	if (usin->sin6_family == AF_INET) {
57 		if (__ipv6_only_sock(sk))
58 			return -EAFNOSUPPORT;
59 		err = ip4_datagram_connect(sk, uaddr, addr_len);
60 		goto ipv4_connected;
61 	}
62 
63 	if (addr_len < SIN6_LEN_RFC2133)
64 		return -EINVAL;
65 
66 	if (usin->sin6_family != AF_INET6)
67 		return -EAFNOSUPPORT;
68 
69 	memset(&fl6, 0, sizeof(fl6));
70 	if (np->sndflow) {
71 		fl6.flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
72 		if (fl6.flowlabel&IPV6_FLOWLABEL_MASK) {
73 			flowlabel = fl6_sock_lookup(sk, fl6.flowlabel);
74 			if (!flowlabel)
75 				return -EINVAL;
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, &sk->sk_v6_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(&sk->sk_v6_rcv_saddr) ||
116 		    ipv6_mapped_addr_any(&sk->sk_v6_rcv_saddr)) {
117 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
118 					       &sk->sk_v6_rcv_saddr);
119 			if (sk->sk_prot->rehash)
120 				sk->sk_prot->rehash(sk);
121 		}
122 
123 		goto out;
124 	}
125 
126 	if (__ipv6_addr_needs_scope_id(addr_type)) {
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 	sk->sk_v6_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 = sk->sk_v6_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);
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(&sk->sk_v6_rcv_saddr)) {
186 		sk->sk_v6_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, &sk->sk_v6_daddr) ?
194 		      &sk->sk_v6_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 	ip6_set_txhash(sk);
203 out:
204 	fl6_sock_release(flowlabel);
205 	return err;
206 }
207 EXPORT_SYMBOL_GPL(ip6_datagram_connect);
208 
209 int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *uaddr,
210 				 int addr_len)
211 {
212 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, uaddr);
213 	if (sin6->sin6_family != AF_INET6)
214 		return -EAFNOSUPPORT;
215 	return ip6_datagram_connect(sk, uaddr, addr_len);
216 }
217 EXPORT_SYMBOL_GPL(ip6_datagram_connect_v6_only);
218 
219 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
220 		     __be16 port, u32 info, u8 *payload)
221 {
222 	struct ipv6_pinfo *np  = inet6_sk(sk);
223 	struct icmp6hdr *icmph = icmp6_hdr(skb);
224 	struct sock_exterr_skb *serr;
225 
226 	if (!np->recverr)
227 		return;
228 
229 	skb = skb_clone(skb, GFP_ATOMIC);
230 	if (!skb)
231 		return;
232 
233 	skb->protocol = htons(ETH_P_IPV6);
234 
235 	serr = SKB_EXT_ERR(skb);
236 	serr->ee.ee_errno = err;
237 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
238 	serr->ee.ee_type = icmph->icmp6_type;
239 	serr->ee.ee_code = icmph->icmp6_code;
240 	serr->ee.ee_pad = 0;
241 	serr->ee.ee_info = info;
242 	serr->ee.ee_data = 0;
243 	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
244 				  skb_network_header(skb);
245 	serr->port = port;
246 
247 	__skb_pull(skb, payload - skb->data);
248 	skb_reset_transport_header(skb);
249 
250 	if (sock_queue_err_skb(sk, skb))
251 		kfree_skb(skb);
252 }
253 
254 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
255 {
256 	struct ipv6_pinfo *np = inet6_sk(sk);
257 	struct sock_exterr_skb *serr;
258 	struct ipv6hdr *iph;
259 	struct sk_buff *skb;
260 
261 	if (!np->recverr)
262 		return;
263 
264 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
265 	if (!skb)
266 		return;
267 
268 	skb->protocol = htons(ETH_P_IPV6);
269 
270 	skb_put(skb, sizeof(struct ipv6hdr));
271 	skb_reset_network_header(skb);
272 	iph = ipv6_hdr(skb);
273 	iph->daddr = fl6->daddr;
274 
275 	serr = SKB_EXT_ERR(skb);
276 	serr->ee.ee_errno = err;
277 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
278 	serr->ee.ee_type = 0;
279 	serr->ee.ee_code = 0;
280 	serr->ee.ee_pad = 0;
281 	serr->ee.ee_info = info;
282 	serr->ee.ee_data = 0;
283 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
284 	serr->port = fl6->fl6_dport;
285 
286 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
287 	skb_reset_transport_header(skb);
288 
289 	if (sock_queue_err_skb(sk, skb))
290 		kfree_skb(skb);
291 }
292 
293 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
294 {
295 	struct ipv6_pinfo *np = inet6_sk(sk);
296 	struct ipv6hdr *iph;
297 	struct sk_buff *skb;
298 	struct ip6_mtuinfo *mtu_info;
299 
300 	if (!np->rxopt.bits.rxpmtu)
301 		return;
302 
303 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
304 	if (!skb)
305 		return;
306 
307 	skb_put(skb, sizeof(struct ipv6hdr));
308 	skb_reset_network_header(skb);
309 	iph = ipv6_hdr(skb);
310 	iph->daddr = fl6->daddr;
311 
312 	mtu_info = IP6CBMTU(skb);
313 
314 	mtu_info->ip6m_mtu = mtu;
315 	mtu_info->ip6m_addr.sin6_family = AF_INET6;
316 	mtu_info->ip6m_addr.sin6_port = 0;
317 	mtu_info->ip6m_addr.sin6_flowinfo = 0;
318 	mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
319 	mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
320 
321 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
322 	skb_reset_transport_header(skb);
323 
324 	skb = xchg(&np->rxpmtu, skb);
325 	kfree_skb(skb);
326 }
327 
328 /* IPv6 supports cmsg on all origins aside from SO_EE_ORIGIN_LOCAL.
329  *
330  * At one point, excluding local errors was a quick test to identify icmp/icmp6
331  * errors. This is no longer true, but the test remained, so the v6 stack,
332  * unlike v4, also honors cmsg requests on all wifi and timestamp errors.
333  *
334  * Timestamp code paths do not initialize the fields expected by cmsg:
335  * the PKTINFO fields in skb->cb[]. Fill those in here.
336  */
337 static bool ip6_datagram_support_cmsg(struct sk_buff *skb,
338 				      struct sock_exterr_skb *serr)
339 {
340 	if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
341 	    serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6)
342 		return true;
343 
344 	if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL)
345 		return false;
346 
347 	if (!skb->dev)
348 		return false;
349 
350 	if (skb->protocol == htons(ETH_P_IPV6))
351 		IP6CB(skb)->iif = skb->dev->ifindex;
352 	else
353 		PKTINFO_SKB_CB(skb)->ipi_ifindex = skb->dev->ifindex;
354 
355 	return true;
356 }
357 
358 /*
359  *	Handle MSG_ERRQUEUE
360  */
361 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
362 {
363 	struct ipv6_pinfo *np = inet6_sk(sk);
364 	struct sock_exterr_skb *serr;
365 	struct sk_buff *skb;
366 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
367 	struct {
368 		struct sock_extended_err ee;
369 		struct sockaddr_in6	 offender;
370 	} errhdr;
371 	int err;
372 	int copied;
373 
374 	err = -EAGAIN;
375 	skb = sock_dequeue_err_skb(sk);
376 	if (!skb)
377 		goto out;
378 
379 	copied = skb->len;
380 	if (copied > len) {
381 		msg->msg_flags |= MSG_TRUNC;
382 		copied = len;
383 	}
384 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
385 	if (err)
386 		goto out_free_skb;
387 
388 	sock_recv_timestamp(msg, sk, skb);
389 
390 	serr = SKB_EXT_ERR(skb);
391 
392 	if (sin && serr->port) {
393 		const unsigned char *nh = skb_network_header(skb);
394 		sin->sin6_family = AF_INET6;
395 		sin->sin6_flowinfo = 0;
396 		sin->sin6_port = serr->port;
397 		if (skb->protocol == htons(ETH_P_IPV6)) {
398 			const struct ipv6hdr *ip6h = container_of((struct in6_addr *)(nh + serr->addr_offset),
399 								  struct ipv6hdr, daddr);
400 			sin->sin6_addr = ip6h->daddr;
401 			if (np->sndflow)
402 				sin->sin6_flowinfo = ip6_flowinfo(ip6h);
403 			sin->sin6_scope_id =
404 				ipv6_iface_scope_id(&sin->sin6_addr,
405 						    IP6CB(skb)->iif);
406 		} else {
407 			ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
408 					       &sin->sin6_addr);
409 			sin->sin6_scope_id = 0;
410 		}
411 		*addr_len = sizeof(*sin);
412 	}
413 
414 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
415 	sin = &errhdr.offender;
416 	memset(sin, 0, sizeof(*sin));
417 
418 	if (ip6_datagram_support_cmsg(skb, serr)) {
419 		sin->sin6_family = AF_INET6;
420 		if (np->rxopt.all)
421 			ip6_datagram_recv_common_ctl(sk, msg, skb);
422 		if (skb->protocol == htons(ETH_P_IPV6)) {
423 			sin->sin6_addr = ipv6_hdr(skb)->saddr;
424 			if (np->rxopt.all)
425 				ip6_datagram_recv_specific_ctl(sk, msg, skb);
426 			sin->sin6_scope_id =
427 				ipv6_iface_scope_id(&sin->sin6_addr,
428 						    IP6CB(skb)->iif);
429 		} else {
430 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
431 					       &sin->sin6_addr);
432 			if (inet_sk(sk)->cmsg_flags)
433 				ip_cmsg_recv(msg, skb);
434 		}
435 	}
436 
437 	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
438 
439 	/* Now we could try to dump offended packet options */
440 
441 	msg->msg_flags |= MSG_ERRQUEUE;
442 	err = copied;
443 
444 out_free_skb:
445 	kfree_skb(skb);
446 out:
447 	return err;
448 }
449 EXPORT_SYMBOL_GPL(ipv6_recv_error);
450 
451 /*
452  *	Handle IPV6_RECVPATHMTU
453  */
454 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len,
455 		     int *addr_len)
456 {
457 	struct ipv6_pinfo *np = inet6_sk(sk);
458 	struct sk_buff *skb;
459 	struct ip6_mtuinfo mtu_info;
460 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
461 	int err;
462 	int copied;
463 
464 	err = -EAGAIN;
465 	skb = xchg(&np->rxpmtu, NULL);
466 	if (!skb)
467 		goto out;
468 
469 	copied = skb->len;
470 	if (copied > len) {
471 		msg->msg_flags |= MSG_TRUNC;
472 		copied = len;
473 	}
474 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
475 	if (err)
476 		goto out_free_skb;
477 
478 	sock_recv_timestamp(msg, sk, skb);
479 
480 	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
481 
482 	if (sin) {
483 		sin->sin6_family = AF_INET6;
484 		sin->sin6_flowinfo = 0;
485 		sin->sin6_port = 0;
486 		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
487 		sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
488 		*addr_len = sizeof(*sin);
489 	}
490 
491 	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
492 
493 	err = copied;
494 
495 out_free_skb:
496 	kfree_skb(skb);
497 out:
498 	return err;
499 }
500 
501 
502 void ip6_datagram_recv_common_ctl(struct sock *sk, struct msghdr *msg,
503 				 struct sk_buff *skb)
504 {
505 	struct ipv6_pinfo *np = inet6_sk(sk);
506 	bool is_ipv6 = skb->protocol == htons(ETH_P_IPV6);
507 
508 	if (np->rxopt.bits.rxinfo) {
509 		struct in6_pktinfo src_info;
510 
511 		if (is_ipv6) {
512 			src_info.ipi6_ifindex = IP6CB(skb)->iif;
513 			src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
514 		} else {
515 			src_info.ipi6_ifindex =
516 				PKTINFO_SKB_CB(skb)->ipi_ifindex;
517 			ipv6_addr_set_v4mapped(ip_hdr(skb)->daddr,
518 					       &src_info.ipi6_addr);
519 		}
520 
521 		if (src_info.ipi6_ifindex >= 0)
522 			put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO,
523 				 sizeof(src_info), &src_info);
524 	}
525 }
526 
527 void ip6_datagram_recv_specific_ctl(struct sock *sk, struct msghdr *msg,
528 				    struct sk_buff *skb)
529 {
530 	struct ipv6_pinfo *np = inet6_sk(sk);
531 	struct inet6_skb_parm *opt = IP6CB(skb);
532 	unsigned char *nh = skb_network_header(skb);
533 
534 	if (np->rxopt.bits.rxhlim) {
535 		int hlim = ipv6_hdr(skb)->hop_limit;
536 		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
537 	}
538 
539 	if (np->rxopt.bits.rxtclass) {
540 		int tclass = ipv6_get_dsfield(ipv6_hdr(skb));
541 		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
542 	}
543 
544 	if (np->rxopt.bits.rxflow) {
545 		__be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
546 		if (flowinfo)
547 			put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
548 	}
549 
550 	/* HbH is allowed only once */
551 	if (np->rxopt.bits.hopopts && opt->hop) {
552 		u8 *ptr = nh + opt->hop;
553 		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
554 	}
555 
556 	if (opt->lastopt &&
557 	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
558 		/*
559 		 * Silly enough, but we need to reparse in order to
560 		 * report extension headers (except for HbH)
561 		 * in order.
562 		 *
563 		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
564 		 * (and WILL NOT be) defined because
565 		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
566 		 */
567 		unsigned int off = sizeof(struct ipv6hdr);
568 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
569 
570 		while (off <= opt->lastopt) {
571 			unsigned int len;
572 			u8 *ptr = nh + off;
573 
574 			switch (nexthdr) {
575 			case IPPROTO_DSTOPTS:
576 				nexthdr = ptr[0];
577 				len = (ptr[1] + 1) << 3;
578 				if (np->rxopt.bits.dstopts)
579 					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
580 				break;
581 			case IPPROTO_ROUTING:
582 				nexthdr = ptr[0];
583 				len = (ptr[1] + 1) << 3;
584 				if (np->rxopt.bits.srcrt)
585 					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
586 				break;
587 			case IPPROTO_AH:
588 				nexthdr = ptr[0];
589 				len = (ptr[1] + 2) << 2;
590 				break;
591 			default:
592 				nexthdr = ptr[0];
593 				len = (ptr[1] + 1) << 3;
594 				break;
595 			}
596 
597 			off += len;
598 		}
599 	}
600 
601 	/* socket options in old style */
602 	if (np->rxopt.bits.rxoinfo) {
603 		struct in6_pktinfo src_info;
604 
605 		src_info.ipi6_ifindex = opt->iif;
606 		src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
607 		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
608 	}
609 	if (np->rxopt.bits.rxohlim) {
610 		int hlim = ipv6_hdr(skb)->hop_limit;
611 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
612 	}
613 	if (np->rxopt.bits.ohopopts && opt->hop) {
614 		u8 *ptr = nh + opt->hop;
615 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
616 	}
617 	if (np->rxopt.bits.odstopts && opt->dst0) {
618 		u8 *ptr = nh + opt->dst0;
619 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
620 	}
621 	if (np->rxopt.bits.osrcrt && opt->srcrt) {
622 		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
623 		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
624 	}
625 	if (np->rxopt.bits.odstopts && opt->dst1) {
626 		u8 *ptr = nh + opt->dst1;
627 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
628 	}
629 	if (np->rxopt.bits.rxorigdstaddr) {
630 		struct sockaddr_in6 sin6;
631 		__be16 *ports = (__be16 *) skb_transport_header(skb);
632 
633 		if (skb_transport_offset(skb) + 4 <= skb->len) {
634 			/* All current transport protocols have the port numbers in the
635 			 * first four bytes of the transport header and this function is
636 			 * written with this assumption in mind.
637 			 */
638 
639 			sin6.sin6_family = AF_INET6;
640 			sin6.sin6_addr = ipv6_hdr(skb)->daddr;
641 			sin6.sin6_port = ports[1];
642 			sin6.sin6_flowinfo = 0;
643 			sin6.sin6_scope_id =
644 				ipv6_iface_scope_id(&ipv6_hdr(skb)->daddr,
645 						    opt->iif);
646 
647 			put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
648 		}
649 	}
650 }
651 
652 void ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
653 			  struct sk_buff *skb)
654 {
655 	ip6_datagram_recv_common_ctl(sk, msg, skb);
656 	ip6_datagram_recv_specific_ctl(sk, msg, skb);
657 }
658 EXPORT_SYMBOL_GPL(ip6_datagram_recv_ctl);
659 
660 int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
661 			  struct msghdr *msg, struct flowi6 *fl6,
662 			  struct ipv6_txoptions *opt,
663 			  int *hlimit, int *tclass, int *dontfrag)
664 {
665 	struct in6_pktinfo *src_info;
666 	struct cmsghdr *cmsg;
667 	struct ipv6_rt_hdr *rthdr;
668 	struct ipv6_opt_hdr *hdr;
669 	int len;
670 	int err = 0;
671 
672 	for_each_cmsghdr(cmsg, msg) {
673 		int addr_type;
674 
675 		if (!CMSG_OK(msg, cmsg)) {
676 			err = -EINVAL;
677 			goto exit_f;
678 		}
679 
680 		if (cmsg->cmsg_level != SOL_IPV6)
681 			continue;
682 
683 		switch (cmsg->cmsg_type) {
684 		case IPV6_PKTINFO:
685 		case IPV6_2292PKTINFO:
686 		    {
687 			struct net_device *dev = NULL;
688 
689 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
690 				err = -EINVAL;
691 				goto exit_f;
692 			}
693 
694 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
695 
696 			if (src_info->ipi6_ifindex) {
697 				if (fl6->flowi6_oif &&
698 				    src_info->ipi6_ifindex != fl6->flowi6_oif)
699 					return -EINVAL;
700 				fl6->flowi6_oif = src_info->ipi6_ifindex;
701 			}
702 
703 			addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
704 
705 			rcu_read_lock();
706 			if (fl6->flowi6_oif) {
707 				dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
708 				if (!dev) {
709 					rcu_read_unlock();
710 					return -ENODEV;
711 				}
712 			} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
713 				rcu_read_unlock();
714 				return -EINVAL;
715 			}
716 
717 			if (addr_type != IPV6_ADDR_ANY) {
718 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
719 				if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
720 				    !ipv6_chk_addr(net, &src_info->ipi6_addr,
721 						   strict ? dev : NULL, 0) &&
722 				    !ipv6_chk_acast_addr_src(net, dev,
723 							     &src_info->ipi6_addr))
724 					err = -EINVAL;
725 				else
726 					fl6->saddr = src_info->ipi6_addr;
727 			}
728 
729 			rcu_read_unlock();
730 
731 			if (err)
732 				goto exit_f;
733 
734 			break;
735 		    }
736 
737 		case IPV6_FLOWINFO:
738 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
739 				err = -EINVAL;
740 				goto exit_f;
741 			}
742 
743 			if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
744 				if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
745 					err = -EINVAL;
746 					goto exit_f;
747 				}
748 			}
749 			fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
750 			break;
751 
752 		case IPV6_2292HOPOPTS:
753 		case IPV6_HOPOPTS:
754 			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
755 				err = -EINVAL;
756 				goto exit_f;
757 			}
758 
759 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
760 			len = ((hdr->hdrlen + 1) << 3);
761 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
762 				err = -EINVAL;
763 				goto exit_f;
764 			}
765 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
766 				err = -EPERM;
767 				goto exit_f;
768 			}
769 			opt->opt_nflen += len;
770 			opt->hopopt = hdr;
771 			break;
772 
773 		case IPV6_2292DSTOPTS:
774 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
775 				err = -EINVAL;
776 				goto exit_f;
777 			}
778 
779 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
780 			len = ((hdr->hdrlen + 1) << 3);
781 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
782 				err = -EINVAL;
783 				goto exit_f;
784 			}
785 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
786 				err = -EPERM;
787 				goto exit_f;
788 			}
789 			if (opt->dst1opt) {
790 				err = -EINVAL;
791 				goto exit_f;
792 			}
793 			opt->opt_flen += len;
794 			opt->dst1opt = hdr;
795 			break;
796 
797 		case IPV6_DSTOPTS:
798 		case IPV6_RTHDRDSTOPTS:
799 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
800 				err = -EINVAL;
801 				goto exit_f;
802 			}
803 
804 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
805 			len = ((hdr->hdrlen + 1) << 3);
806 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
807 				err = -EINVAL;
808 				goto exit_f;
809 			}
810 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
811 				err = -EPERM;
812 				goto exit_f;
813 			}
814 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
815 				opt->opt_flen += len;
816 				opt->dst1opt = hdr;
817 			} else {
818 				opt->opt_nflen += len;
819 				opt->dst0opt = hdr;
820 			}
821 			break;
822 
823 		case IPV6_2292RTHDR:
824 		case IPV6_RTHDR:
825 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
826 				err = -EINVAL;
827 				goto exit_f;
828 			}
829 
830 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
831 
832 			switch (rthdr->type) {
833 #if IS_ENABLED(CONFIG_IPV6_MIP6)
834 			case IPV6_SRCRT_TYPE_2:
835 				if (rthdr->hdrlen != 2 ||
836 				    rthdr->segments_left != 1) {
837 					err = -EINVAL;
838 					goto exit_f;
839 				}
840 				break;
841 #endif
842 			default:
843 				err = -EINVAL;
844 				goto exit_f;
845 			}
846 
847 			len = ((rthdr->hdrlen + 1) << 3);
848 
849 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
850 				err = -EINVAL;
851 				goto exit_f;
852 			}
853 
854 			/* segments left must also match */
855 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
856 				err = -EINVAL;
857 				goto exit_f;
858 			}
859 
860 			opt->opt_nflen += len;
861 			opt->srcrt = rthdr;
862 
863 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
864 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
865 
866 				opt->opt_nflen += dsthdrlen;
867 				opt->dst0opt = opt->dst1opt;
868 				opt->dst1opt = NULL;
869 				opt->opt_flen -= dsthdrlen;
870 			}
871 
872 			break;
873 
874 		case IPV6_2292HOPLIMIT:
875 		case IPV6_HOPLIMIT:
876 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
877 				err = -EINVAL;
878 				goto exit_f;
879 			}
880 
881 			*hlimit = *(int *)CMSG_DATA(cmsg);
882 			if (*hlimit < -1 || *hlimit > 0xff) {
883 				err = -EINVAL;
884 				goto exit_f;
885 			}
886 
887 			break;
888 
889 		case IPV6_TCLASS:
890 		    {
891 			int tc;
892 
893 			err = -EINVAL;
894 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
895 				goto exit_f;
896 
897 			tc = *(int *)CMSG_DATA(cmsg);
898 			if (tc < -1 || tc > 0xff)
899 				goto exit_f;
900 
901 			err = 0;
902 			*tclass = tc;
903 
904 			break;
905 		    }
906 
907 		case IPV6_DONTFRAG:
908 		    {
909 			int df;
910 
911 			err = -EINVAL;
912 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
913 				goto exit_f;
914 
915 			df = *(int *)CMSG_DATA(cmsg);
916 			if (df < 0 || df > 1)
917 				goto exit_f;
918 
919 			err = 0;
920 			*dontfrag = df;
921 
922 			break;
923 		    }
924 		default:
925 			net_dbg_ratelimited("invalid cmsg type: %d\n",
926 					    cmsg->cmsg_type);
927 			err = -EINVAL;
928 			goto exit_f;
929 		}
930 	}
931 
932 exit_f:
933 	return err;
934 }
935 EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
936 
937 void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
938 			     __u16 srcp, __u16 destp, int bucket)
939 {
940 	const struct in6_addr *dest, *src;
941 
942 	dest  = &sp->sk_v6_daddr;
943 	src   = &sp->sk_v6_rcv_saddr;
944 	seq_printf(seq,
945 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
946 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d\n",
947 		   bucket,
948 		   src->s6_addr32[0], src->s6_addr32[1],
949 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
950 		   dest->s6_addr32[0], dest->s6_addr32[1],
951 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
952 		   sp->sk_state,
953 		   sk_wmem_alloc_get(sp),
954 		   sk_rmem_alloc_get(sp),
955 		   0, 0L, 0,
956 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
957 		   0,
958 		   sock_i_ino(sp),
959 		   atomic_read(&sp->sk_refcnt), sp,
960 		   atomic_read(&sp->sk_drops));
961 }
962