xref: /openbmc/linux/net/ipv6/datagram.c (revision 9cfc5c90)
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 static 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 	sk_set_txhash(sk);
203 out:
204 	fl6_sock_release(flowlabel);
205 	return err;
206 }
207 
208 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
209 {
210 	int res;
211 
212 	lock_sock(sk);
213 	res = __ip6_datagram_connect(sk, uaddr, addr_len);
214 	release_sock(sk);
215 	return res;
216 }
217 EXPORT_SYMBOL_GPL(ip6_datagram_connect);
218 
219 int ip6_datagram_connect_v6_only(struct sock *sk, struct sockaddr *uaddr,
220 				 int addr_len)
221 {
222 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, uaddr);
223 	if (sin6->sin6_family != AF_INET6)
224 		return -EAFNOSUPPORT;
225 	return ip6_datagram_connect(sk, uaddr, addr_len);
226 }
227 EXPORT_SYMBOL_GPL(ip6_datagram_connect_v6_only);
228 
229 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
230 		     __be16 port, u32 info, u8 *payload)
231 {
232 	struct ipv6_pinfo *np  = inet6_sk(sk);
233 	struct icmp6hdr *icmph = icmp6_hdr(skb);
234 	struct sock_exterr_skb *serr;
235 
236 	if (!np->recverr)
237 		return;
238 
239 	skb = skb_clone(skb, GFP_ATOMIC);
240 	if (!skb)
241 		return;
242 
243 	skb->protocol = htons(ETH_P_IPV6);
244 
245 	serr = SKB_EXT_ERR(skb);
246 	serr->ee.ee_errno = err;
247 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
248 	serr->ee.ee_type = icmph->icmp6_type;
249 	serr->ee.ee_code = icmph->icmp6_code;
250 	serr->ee.ee_pad = 0;
251 	serr->ee.ee_info = info;
252 	serr->ee.ee_data = 0;
253 	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
254 				  skb_network_header(skb);
255 	serr->port = port;
256 
257 	__skb_pull(skb, payload - skb->data);
258 	skb_reset_transport_header(skb);
259 
260 	if (sock_queue_err_skb(sk, skb))
261 		kfree_skb(skb);
262 }
263 
264 void ipv6_local_error(struct sock *sk, int err, struct flowi6 *fl6, u32 info)
265 {
266 	const struct ipv6_pinfo *np = inet6_sk(sk);
267 	struct sock_exterr_skb *serr;
268 	struct ipv6hdr *iph;
269 	struct sk_buff *skb;
270 
271 	if (!np->recverr)
272 		return;
273 
274 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
275 	if (!skb)
276 		return;
277 
278 	skb->protocol = htons(ETH_P_IPV6);
279 
280 	skb_put(skb, sizeof(struct ipv6hdr));
281 	skb_reset_network_header(skb);
282 	iph = ipv6_hdr(skb);
283 	iph->daddr = fl6->daddr;
284 
285 	serr = SKB_EXT_ERR(skb);
286 	serr->ee.ee_errno = err;
287 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
288 	serr->ee.ee_type = 0;
289 	serr->ee.ee_code = 0;
290 	serr->ee.ee_pad = 0;
291 	serr->ee.ee_info = info;
292 	serr->ee.ee_data = 0;
293 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
294 	serr->port = fl6->fl6_dport;
295 
296 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
297 	skb_reset_transport_header(skb);
298 
299 	if (sock_queue_err_skb(sk, skb))
300 		kfree_skb(skb);
301 }
302 
303 void ipv6_local_rxpmtu(struct sock *sk, struct flowi6 *fl6, u32 mtu)
304 {
305 	struct ipv6_pinfo *np = inet6_sk(sk);
306 	struct ipv6hdr *iph;
307 	struct sk_buff *skb;
308 	struct ip6_mtuinfo *mtu_info;
309 
310 	if (!np->rxopt.bits.rxpmtu)
311 		return;
312 
313 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
314 	if (!skb)
315 		return;
316 
317 	skb_put(skb, sizeof(struct ipv6hdr));
318 	skb_reset_network_header(skb);
319 	iph = ipv6_hdr(skb);
320 	iph->daddr = fl6->daddr;
321 
322 	mtu_info = IP6CBMTU(skb);
323 
324 	mtu_info->ip6m_mtu = mtu;
325 	mtu_info->ip6m_addr.sin6_family = AF_INET6;
326 	mtu_info->ip6m_addr.sin6_port = 0;
327 	mtu_info->ip6m_addr.sin6_flowinfo = 0;
328 	mtu_info->ip6m_addr.sin6_scope_id = fl6->flowi6_oif;
329 	mtu_info->ip6m_addr.sin6_addr = ipv6_hdr(skb)->daddr;
330 
331 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
332 	skb_reset_transport_header(skb);
333 
334 	skb = xchg(&np->rxpmtu, skb);
335 	kfree_skb(skb);
336 }
337 
338 /* For some errors we have valid addr_offset even with zero payload and
339  * zero port. Also, addr_offset should be supported if port is set.
340  */
341 static inline bool ipv6_datagram_support_addr(struct sock_exterr_skb *serr)
342 {
343 	return serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6 ||
344 	       serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
345 	       serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL || serr->port;
346 }
347 
348 /* IPv6 supports cmsg on all origins aside from SO_EE_ORIGIN_LOCAL.
349  *
350  * At one point, excluding local errors was a quick test to identify icmp/icmp6
351  * errors. This is no longer true, but the test remained, so the v6 stack,
352  * unlike v4, also honors cmsg requests on all wifi and timestamp errors.
353  *
354  * Timestamp code paths do not initialize the fields expected by cmsg:
355  * the PKTINFO fields in skb->cb[]. Fill those in here.
356  */
357 static bool ip6_datagram_support_cmsg(struct sk_buff *skb,
358 				      struct sock_exterr_skb *serr)
359 {
360 	if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
361 	    serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6)
362 		return true;
363 
364 	if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL)
365 		return false;
366 
367 	if (!skb->dev)
368 		return false;
369 
370 	if (skb->protocol == htons(ETH_P_IPV6))
371 		IP6CB(skb)->iif = skb->dev->ifindex;
372 	else
373 		PKTINFO_SKB_CB(skb)->ipi_ifindex = skb->dev->ifindex;
374 
375 	return true;
376 }
377 
378 /*
379  *	Handle MSG_ERRQUEUE
380  */
381 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
382 {
383 	struct ipv6_pinfo *np = inet6_sk(sk);
384 	struct sock_exterr_skb *serr;
385 	struct sk_buff *skb;
386 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
387 	struct {
388 		struct sock_extended_err ee;
389 		struct sockaddr_in6	 offender;
390 	} errhdr;
391 	int err;
392 	int copied;
393 
394 	err = -EAGAIN;
395 	skb = sock_dequeue_err_skb(sk);
396 	if (!skb)
397 		goto out;
398 
399 	copied = skb->len;
400 	if (copied > len) {
401 		msg->msg_flags |= MSG_TRUNC;
402 		copied = len;
403 	}
404 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
405 	if (err)
406 		goto out_free_skb;
407 
408 	sock_recv_timestamp(msg, sk, skb);
409 
410 	serr = SKB_EXT_ERR(skb);
411 
412 	if (sin && ipv6_datagram_support_addr(serr)) {
413 		const unsigned char *nh = skb_network_header(skb);
414 		sin->sin6_family = AF_INET6;
415 		sin->sin6_flowinfo = 0;
416 		sin->sin6_port = serr->port;
417 		if (skb->protocol == htons(ETH_P_IPV6)) {
418 			const struct ipv6hdr *ip6h = container_of((struct in6_addr *)(nh + serr->addr_offset),
419 								  struct ipv6hdr, daddr);
420 			sin->sin6_addr = ip6h->daddr;
421 			if (np->sndflow)
422 				sin->sin6_flowinfo = ip6_flowinfo(ip6h);
423 			sin->sin6_scope_id =
424 				ipv6_iface_scope_id(&sin->sin6_addr,
425 						    IP6CB(skb)->iif);
426 		} else {
427 			ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
428 					       &sin->sin6_addr);
429 			sin->sin6_scope_id = 0;
430 		}
431 		*addr_len = sizeof(*sin);
432 	}
433 
434 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
435 	sin = &errhdr.offender;
436 	memset(sin, 0, sizeof(*sin));
437 
438 	if (ip6_datagram_support_cmsg(skb, serr)) {
439 		sin->sin6_family = AF_INET6;
440 		if (np->rxopt.all)
441 			ip6_datagram_recv_common_ctl(sk, msg, skb);
442 		if (skb->protocol == htons(ETH_P_IPV6)) {
443 			sin->sin6_addr = ipv6_hdr(skb)->saddr;
444 			if (np->rxopt.all)
445 				ip6_datagram_recv_specific_ctl(sk, msg, skb);
446 			sin->sin6_scope_id =
447 				ipv6_iface_scope_id(&sin->sin6_addr,
448 						    IP6CB(skb)->iif);
449 		} else {
450 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
451 					       &sin->sin6_addr);
452 			if (inet_sk(sk)->cmsg_flags)
453 				ip_cmsg_recv(msg, skb);
454 		}
455 	}
456 
457 	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
458 
459 	/* Now we could try to dump offended packet options */
460 
461 	msg->msg_flags |= MSG_ERRQUEUE;
462 	err = copied;
463 
464 out_free_skb:
465 	kfree_skb(skb);
466 out:
467 	return err;
468 }
469 EXPORT_SYMBOL_GPL(ipv6_recv_error);
470 
471 /*
472  *	Handle IPV6_RECVPATHMTU
473  */
474 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len,
475 		     int *addr_len)
476 {
477 	struct ipv6_pinfo *np = inet6_sk(sk);
478 	struct sk_buff *skb;
479 	struct ip6_mtuinfo mtu_info;
480 	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin, msg->msg_name);
481 	int err;
482 	int copied;
483 
484 	err = -EAGAIN;
485 	skb = xchg(&np->rxpmtu, NULL);
486 	if (!skb)
487 		goto out;
488 
489 	copied = skb->len;
490 	if (copied > len) {
491 		msg->msg_flags |= MSG_TRUNC;
492 		copied = len;
493 	}
494 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
495 	if (err)
496 		goto out_free_skb;
497 
498 	sock_recv_timestamp(msg, sk, skb);
499 
500 	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
501 
502 	if (sin) {
503 		sin->sin6_family = AF_INET6;
504 		sin->sin6_flowinfo = 0;
505 		sin->sin6_port = 0;
506 		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
507 		sin->sin6_addr = mtu_info.ip6m_addr.sin6_addr;
508 		*addr_len = sizeof(*sin);
509 	}
510 
511 	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
512 
513 	err = copied;
514 
515 out_free_skb:
516 	kfree_skb(skb);
517 out:
518 	return err;
519 }
520 
521 
522 void ip6_datagram_recv_common_ctl(struct sock *sk, struct msghdr *msg,
523 				 struct sk_buff *skb)
524 {
525 	struct ipv6_pinfo *np = inet6_sk(sk);
526 	bool is_ipv6 = skb->protocol == htons(ETH_P_IPV6);
527 
528 	if (np->rxopt.bits.rxinfo) {
529 		struct in6_pktinfo src_info;
530 
531 		if (is_ipv6) {
532 			src_info.ipi6_ifindex = IP6CB(skb)->iif;
533 			src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
534 		} else {
535 			src_info.ipi6_ifindex =
536 				PKTINFO_SKB_CB(skb)->ipi_ifindex;
537 			ipv6_addr_set_v4mapped(ip_hdr(skb)->daddr,
538 					       &src_info.ipi6_addr);
539 		}
540 
541 		if (src_info.ipi6_ifindex >= 0)
542 			put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO,
543 				 sizeof(src_info), &src_info);
544 	}
545 }
546 
547 void ip6_datagram_recv_specific_ctl(struct sock *sk, struct msghdr *msg,
548 				    struct sk_buff *skb)
549 {
550 	struct ipv6_pinfo *np = inet6_sk(sk);
551 	struct inet6_skb_parm *opt = IP6CB(skb);
552 	unsigned char *nh = skb_network_header(skb);
553 
554 	if (np->rxopt.bits.rxhlim) {
555 		int hlim = ipv6_hdr(skb)->hop_limit;
556 		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
557 	}
558 
559 	if (np->rxopt.bits.rxtclass) {
560 		int tclass = ipv6_get_dsfield(ipv6_hdr(skb));
561 		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
562 	}
563 
564 	if (np->rxopt.bits.rxflow) {
565 		__be32 flowinfo = ip6_flowinfo((struct ipv6hdr *)nh);
566 		if (flowinfo)
567 			put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
568 	}
569 
570 	/* HbH is allowed only once */
571 	if (np->rxopt.bits.hopopts && (opt->flags & IP6SKB_HOPBYHOP)) {
572 		u8 *ptr = nh + sizeof(struct ipv6hdr);
573 		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
574 	}
575 
576 	if (opt->lastopt &&
577 	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
578 		/*
579 		 * Silly enough, but we need to reparse in order to
580 		 * report extension headers (except for HbH)
581 		 * in order.
582 		 *
583 		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
584 		 * (and WILL NOT be) defined because
585 		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
586 		 */
587 		unsigned int off = sizeof(struct ipv6hdr);
588 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
589 
590 		while (off <= opt->lastopt) {
591 			unsigned int len;
592 			u8 *ptr = nh + off;
593 
594 			switch (nexthdr) {
595 			case IPPROTO_DSTOPTS:
596 				nexthdr = ptr[0];
597 				len = (ptr[1] + 1) << 3;
598 				if (np->rxopt.bits.dstopts)
599 					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
600 				break;
601 			case IPPROTO_ROUTING:
602 				nexthdr = ptr[0];
603 				len = (ptr[1] + 1) << 3;
604 				if (np->rxopt.bits.srcrt)
605 					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
606 				break;
607 			case IPPROTO_AH:
608 				nexthdr = ptr[0];
609 				len = (ptr[1] + 2) << 2;
610 				break;
611 			default:
612 				nexthdr = ptr[0];
613 				len = (ptr[1] + 1) << 3;
614 				break;
615 			}
616 
617 			off += len;
618 		}
619 	}
620 
621 	/* socket options in old style */
622 	if (np->rxopt.bits.rxoinfo) {
623 		struct in6_pktinfo src_info;
624 
625 		src_info.ipi6_ifindex = opt->iif;
626 		src_info.ipi6_addr = ipv6_hdr(skb)->daddr;
627 		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
628 	}
629 	if (np->rxopt.bits.rxohlim) {
630 		int hlim = ipv6_hdr(skb)->hop_limit;
631 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
632 	}
633 	if (np->rxopt.bits.ohopopts && (opt->flags & IP6SKB_HOPBYHOP)) {
634 		u8 *ptr = nh + sizeof(struct ipv6hdr);
635 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
636 	}
637 	if (np->rxopt.bits.odstopts && opt->dst0) {
638 		u8 *ptr = nh + opt->dst0;
639 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
640 	}
641 	if (np->rxopt.bits.osrcrt && opt->srcrt) {
642 		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
643 		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
644 	}
645 	if (np->rxopt.bits.odstopts && opt->dst1) {
646 		u8 *ptr = nh + opt->dst1;
647 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
648 	}
649 	if (np->rxopt.bits.rxorigdstaddr) {
650 		struct sockaddr_in6 sin6;
651 		__be16 *ports = (__be16 *) skb_transport_header(skb);
652 
653 		if (skb_transport_offset(skb) + 4 <= skb->len) {
654 			/* All current transport protocols have the port numbers in the
655 			 * first four bytes of the transport header and this function is
656 			 * written with this assumption in mind.
657 			 */
658 
659 			sin6.sin6_family = AF_INET6;
660 			sin6.sin6_addr = ipv6_hdr(skb)->daddr;
661 			sin6.sin6_port = ports[1];
662 			sin6.sin6_flowinfo = 0;
663 			sin6.sin6_scope_id =
664 				ipv6_iface_scope_id(&ipv6_hdr(skb)->daddr,
665 						    opt->iif);
666 
667 			put_cmsg(msg, SOL_IPV6, IPV6_ORIGDSTADDR, sizeof(sin6), &sin6);
668 		}
669 	}
670 }
671 
672 void ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,
673 			  struct sk_buff *skb)
674 {
675 	ip6_datagram_recv_common_ctl(sk, msg, skb);
676 	ip6_datagram_recv_specific_ctl(sk, msg, skb);
677 }
678 EXPORT_SYMBOL_GPL(ip6_datagram_recv_ctl);
679 
680 int ip6_datagram_send_ctl(struct net *net, struct sock *sk,
681 			  struct msghdr *msg, struct flowi6 *fl6,
682 			  struct ipv6_txoptions *opt,
683 			  int *hlimit, int *tclass, int *dontfrag)
684 {
685 	struct in6_pktinfo *src_info;
686 	struct cmsghdr *cmsg;
687 	struct ipv6_rt_hdr *rthdr;
688 	struct ipv6_opt_hdr *hdr;
689 	int len;
690 	int err = 0;
691 
692 	for_each_cmsghdr(cmsg, msg) {
693 		int addr_type;
694 
695 		if (!CMSG_OK(msg, cmsg)) {
696 			err = -EINVAL;
697 			goto exit_f;
698 		}
699 
700 		if (cmsg->cmsg_level != SOL_IPV6)
701 			continue;
702 
703 		switch (cmsg->cmsg_type) {
704 		case IPV6_PKTINFO:
705 		case IPV6_2292PKTINFO:
706 		    {
707 			struct net_device *dev = NULL;
708 
709 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
710 				err = -EINVAL;
711 				goto exit_f;
712 			}
713 
714 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
715 
716 			if (src_info->ipi6_ifindex) {
717 				if (fl6->flowi6_oif &&
718 				    src_info->ipi6_ifindex != fl6->flowi6_oif)
719 					return -EINVAL;
720 				fl6->flowi6_oif = src_info->ipi6_ifindex;
721 			}
722 
723 			addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
724 
725 			rcu_read_lock();
726 			if (fl6->flowi6_oif) {
727 				dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
728 				if (!dev) {
729 					rcu_read_unlock();
730 					return -ENODEV;
731 				}
732 			} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
733 				rcu_read_unlock();
734 				return -EINVAL;
735 			}
736 
737 			if (addr_type != IPV6_ADDR_ANY) {
738 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
739 				if (!(inet_sk(sk)->freebind || inet_sk(sk)->transparent) &&
740 				    !ipv6_chk_addr(net, &src_info->ipi6_addr,
741 						   strict ? dev : NULL, 0) &&
742 				    !ipv6_chk_acast_addr_src(net, dev,
743 							     &src_info->ipi6_addr))
744 					err = -EINVAL;
745 				else
746 					fl6->saddr = src_info->ipi6_addr;
747 			}
748 
749 			rcu_read_unlock();
750 
751 			if (err)
752 				goto exit_f;
753 
754 			break;
755 		    }
756 
757 		case IPV6_FLOWINFO:
758 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
759 				err = -EINVAL;
760 				goto exit_f;
761 			}
762 
763 			if (fl6->flowlabel&IPV6_FLOWINFO_MASK) {
764 				if ((fl6->flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
765 					err = -EINVAL;
766 					goto exit_f;
767 				}
768 			}
769 			fl6->flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
770 			break;
771 
772 		case IPV6_2292HOPOPTS:
773 		case IPV6_HOPOPTS:
774 			if (opt->hopopt || 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 			opt->opt_nflen += len;
790 			opt->hopopt = hdr;
791 			break;
792 
793 		case IPV6_2292DSTOPTS:
794 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
795 				err = -EINVAL;
796 				goto exit_f;
797 			}
798 
799 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
800 			len = ((hdr->hdrlen + 1) << 3);
801 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
802 				err = -EINVAL;
803 				goto exit_f;
804 			}
805 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
806 				err = -EPERM;
807 				goto exit_f;
808 			}
809 			if (opt->dst1opt) {
810 				err = -EINVAL;
811 				goto exit_f;
812 			}
813 			opt->opt_flen += len;
814 			opt->dst1opt = hdr;
815 			break;
816 
817 		case IPV6_DSTOPTS:
818 		case IPV6_RTHDRDSTOPTS:
819 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
820 				err = -EINVAL;
821 				goto exit_f;
822 			}
823 
824 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
825 			len = ((hdr->hdrlen + 1) << 3);
826 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
827 				err = -EINVAL;
828 				goto exit_f;
829 			}
830 			if (!ns_capable(net->user_ns, CAP_NET_RAW)) {
831 				err = -EPERM;
832 				goto exit_f;
833 			}
834 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
835 				opt->opt_flen += len;
836 				opt->dst1opt = hdr;
837 			} else {
838 				opt->opt_nflen += len;
839 				opt->dst0opt = hdr;
840 			}
841 			break;
842 
843 		case IPV6_2292RTHDR:
844 		case IPV6_RTHDR:
845 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
846 				err = -EINVAL;
847 				goto exit_f;
848 			}
849 
850 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
851 
852 			switch (rthdr->type) {
853 #if IS_ENABLED(CONFIG_IPV6_MIP6)
854 			case IPV6_SRCRT_TYPE_2:
855 				if (rthdr->hdrlen != 2 ||
856 				    rthdr->segments_left != 1) {
857 					err = -EINVAL;
858 					goto exit_f;
859 				}
860 				break;
861 #endif
862 			default:
863 				err = -EINVAL;
864 				goto exit_f;
865 			}
866 
867 			len = ((rthdr->hdrlen + 1) << 3);
868 
869 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
870 				err = -EINVAL;
871 				goto exit_f;
872 			}
873 
874 			/* segments left must also match */
875 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
876 				err = -EINVAL;
877 				goto exit_f;
878 			}
879 
880 			opt->opt_nflen += len;
881 			opt->srcrt = rthdr;
882 
883 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
884 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
885 
886 				opt->opt_nflen += dsthdrlen;
887 				opt->dst0opt = opt->dst1opt;
888 				opt->dst1opt = NULL;
889 				opt->opt_flen -= dsthdrlen;
890 			}
891 
892 			break;
893 
894 		case IPV6_2292HOPLIMIT:
895 		case IPV6_HOPLIMIT:
896 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
897 				err = -EINVAL;
898 				goto exit_f;
899 			}
900 
901 			*hlimit = *(int *)CMSG_DATA(cmsg);
902 			if (*hlimit < -1 || *hlimit > 0xff) {
903 				err = -EINVAL;
904 				goto exit_f;
905 			}
906 
907 			break;
908 
909 		case IPV6_TCLASS:
910 		    {
911 			int tc;
912 
913 			err = -EINVAL;
914 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
915 				goto exit_f;
916 
917 			tc = *(int *)CMSG_DATA(cmsg);
918 			if (tc < -1 || tc > 0xff)
919 				goto exit_f;
920 
921 			err = 0;
922 			*tclass = tc;
923 
924 			break;
925 		    }
926 
927 		case IPV6_DONTFRAG:
928 		    {
929 			int df;
930 
931 			err = -EINVAL;
932 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
933 				goto exit_f;
934 
935 			df = *(int *)CMSG_DATA(cmsg);
936 			if (df < 0 || df > 1)
937 				goto exit_f;
938 
939 			err = 0;
940 			*dontfrag = df;
941 
942 			break;
943 		    }
944 		default:
945 			net_dbg_ratelimited("invalid cmsg type: %d\n",
946 					    cmsg->cmsg_type);
947 			err = -EINVAL;
948 			goto exit_f;
949 		}
950 	}
951 
952 exit_f:
953 	return err;
954 }
955 EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
956 
957 void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp,
958 			     __u16 srcp, __u16 destp, int bucket)
959 {
960 	const struct in6_addr *dest, *src;
961 
962 	dest  = &sp->sk_v6_daddr;
963 	src   = &sp->sk_v6_rcv_saddr;
964 	seq_printf(seq,
965 		   "%5d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
966 		   "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d\n",
967 		   bucket,
968 		   src->s6_addr32[0], src->s6_addr32[1],
969 		   src->s6_addr32[2], src->s6_addr32[3], srcp,
970 		   dest->s6_addr32[0], dest->s6_addr32[1],
971 		   dest->s6_addr32[2], dest->s6_addr32[3], destp,
972 		   sp->sk_state,
973 		   sk_wmem_alloc_get(sp),
974 		   sk_rmem_alloc_get(sp),
975 		   0, 0L, 0,
976 		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
977 		   0,
978 		   sock_i_ino(sp),
979 		   atomic_read(&sp->sk_refcnt), sp,
980 		   atomic_read(&sp->sk_drops));
981 }
982