xref: /linux/net/ipv6/datagram.c (revision e190bfe56841551b1ad5abb42ebd0c4798cc8c01)
1 /*
2  *	common UDP/RAW code
3  *	Linux INET6 implementation
4  *
5  *	Authors:
6  *	Pedro Roque		<roque@di.fc.ul.pt>
7  *
8  *	This program is free software; you can redistribute it and/or
9  *      modify it under the terms of the GNU General Public License
10  *      as published by the Free Software Foundation; either version
11  *      2 of the License, or (at your option) any later version.
12  */
13 
14 #include <linux/capability.h>
15 #include <linux/errno.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/interrupt.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/in6.h>
22 #include <linux/ipv6.h>
23 #include <linux/route.h>
24 #include <linux/slab.h>
25 
26 #include <net/ipv6.h>
27 #include <net/ndisc.h>
28 #include <net/addrconf.h>
29 #include <net/transp_v6.h>
30 #include <net/ip6_route.h>
31 #include <net/tcp_states.h>
32 
33 #include <linux/errqueue.h>
34 #include <asm/uaccess.h>
35 
36 int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
37 {
38 	struct sockaddr_in6	*usin = (struct sockaddr_in6 *) uaddr;
39 	struct inet_sock      	*inet = inet_sk(sk);
40 	struct ipv6_pinfo      	*np = inet6_sk(sk);
41 	struct in6_addr		*daddr, *final_p = NULL, final;
42 	struct dst_entry	*dst;
43 	struct flowi		fl;
44 	struct ip6_flowlabel	*flowlabel = NULL;
45 	int			addr_type;
46 	int			err;
47 
48 	if (usin->sin6_family == AF_INET) {
49 		if (__ipv6_only_sock(sk))
50 			return -EAFNOSUPPORT;
51 		err = ip4_datagram_connect(sk, uaddr, addr_len);
52 		goto ipv4_connected;
53 	}
54 
55 	if (addr_len < SIN6_LEN_RFC2133)
56 		return -EINVAL;
57 
58 	if (usin->sin6_family != AF_INET6)
59 		return -EAFNOSUPPORT;
60 
61 	memset(&fl, 0, sizeof(fl));
62 	if (np->sndflow) {
63 		fl.fl6_flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
64 		if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
65 			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
66 			if (flowlabel == NULL)
67 				return -EINVAL;
68 			ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
69 		}
70 	}
71 
72 	addr_type = ipv6_addr_type(&usin->sin6_addr);
73 
74 	if (addr_type == IPV6_ADDR_ANY) {
75 		/*
76 		 *	connect to self
77 		 */
78 		usin->sin6_addr.s6_addr[15] = 0x01;
79 	}
80 
81 	daddr = &usin->sin6_addr;
82 
83 	if (addr_type == IPV6_ADDR_MAPPED) {
84 		struct sockaddr_in sin;
85 
86 		if (__ipv6_only_sock(sk)) {
87 			err = -ENETUNREACH;
88 			goto out;
89 		}
90 		sin.sin_family = AF_INET;
91 		sin.sin_addr.s_addr = daddr->s6_addr32[3];
92 		sin.sin_port = usin->sin6_port;
93 
94 		err = ip4_datagram_connect(sk,
95 					   (struct sockaddr*) &sin,
96 					   sizeof(sin));
97 
98 ipv4_connected:
99 		if (err)
100 			goto out;
101 
102 		ipv6_addr_set_v4mapped(inet->inet_daddr, &np->daddr);
103 
104 		if (ipv6_addr_any(&np->saddr))
105 			ipv6_addr_set_v4mapped(inet->inet_saddr, &np->saddr);
106 
107 		if (ipv6_addr_any(&np->rcv_saddr))
108 			ipv6_addr_set_v4mapped(inet->inet_rcv_saddr,
109 					       &np->rcv_saddr);
110 
111 		goto out;
112 	}
113 
114 	if (addr_type&IPV6_ADDR_LINKLOCAL) {
115 		if (addr_len >= sizeof(struct sockaddr_in6) &&
116 		    usin->sin6_scope_id) {
117 			if (sk->sk_bound_dev_if &&
118 			    sk->sk_bound_dev_if != usin->sin6_scope_id) {
119 				err = -EINVAL;
120 				goto out;
121 			}
122 			sk->sk_bound_dev_if = usin->sin6_scope_id;
123 		}
124 
125 		if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
126 			sk->sk_bound_dev_if = np->mcast_oif;
127 
128 		/* Connect to link-local address requires an interface */
129 		if (!sk->sk_bound_dev_if) {
130 			err = -EINVAL;
131 			goto out;
132 		}
133 	}
134 
135 	ipv6_addr_copy(&np->daddr, daddr);
136 	np->flow_label = fl.fl6_flowlabel;
137 
138 	inet->inet_dport = usin->sin6_port;
139 
140 	/*
141 	 *	Check for a route to destination an obtain the
142 	 *	destination cache for it.
143 	 */
144 
145 	fl.proto = sk->sk_protocol;
146 	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
147 	ipv6_addr_copy(&fl.fl6_src, &np->saddr);
148 	fl.oif = sk->sk_bound_dev_if;
149 	fl.mark = sk->sk_mark;
150 	fl.fl_ip_dport = inet->inet_dport;
151 	fl.fl_ip_sport = inet->inet_sport;
152 
153 	if (!fl.oif && (addr_type&IPV6_ADDR_MULTICAST))
154 		fl.oif = np->mcast_oif;
155 
156 	security_sk_classify_flow(sk, &fl);
157 
158 	if (flowlabel) {
159 		if (flowlabel->opt && flowlabel->opt->srcrt) {
160 			struct rt0_hdr *rt0 = (struct rt0_hdr *) flowlabel->opt->srcrt;
161 			ipv6_addr_copy(&final, &fl.fl6_dst);
162 			ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
163 			final_p = &final;
164 		}
165 	} else if (np->opt && np->opt->srcrt) {
166 		struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
167 		ipv6_addr_copy(&final, &fl.fl6_dst);
168 		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
169 		final_p = &final;
170 	}
171 
172 	err = ip6_dst_lookup(sk, &dst, &fl);
173 	if (err)
174 		goto out;
175 	if (final_p)
176 		ipv6_addr_copy(&fl.fl6_dst, final_p);
177 
178 	err = __xfrm_lookup(sock_net(sk), &dst, &fl, sk, XFRM_LOOKUP_WAIT);
179 	if (err < 0) {
180 		if (err == -EREMOTE)
181 			err = ip6_dst_blackhole(sk, &dst, &fl);
182 		if (err < 0)
183 			goto out;
184 	}
185 
186 	/* source address lookup done in ip6_dst_lookup */
187 
188 	if (ipv6_addr_any(&np->saddr))
189 		ipv6_addr_copy(&np->saddr, &fl.fl6_src);
190 
191 	if (ipv6_addr_any(&np->rcv_saddr)) {
192 		ipv6_addr_copy(&np->rcv_saddr, &fl.fl6_src);
193 		inet->inet_rcv_saddr = LOOPBACK4_IPV6;
194 	}
195 
196 	ip6_dst_store(sk, dst,
197 		      ipv6_addr_equal(&fl.fl6_dst, &np->daddr) ?
198 		      &np->daddr : NULL,
199 #ifdef CONFIG_IPV6_SUBTREES
200 		      ipv6_addr_equal(&fl.fl6_src, &np->saddr) ?
201 		      &np->saddr :
202 #endif
203 		      NULL);
204 
205 	sk->sk_state = TCP_ESTABLISHED;
206 out:
207 	fl6_sock_release(flowlabel);
208 	return err;
209 }
210 
211 void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
212 		     __be16 port, u32 info, u8 *payload)
213 {
214 	struct ipv6_pinfo *np  = inet6_sk(sk);
215 	struct icmp6hdr *icmph = icmp6_hdr(skb);
216 	struct sock_exterr_skb *serr;
217 
218 	if (!np->recverr)
219 		return;
220 
221 	skb = skb_clone(skb, GFP_ATOMIC);
222 	if (!skb)
223 		return;
224 
225 	skb->protocol = htons(ETH_P_IPV6);
226 
227 	serr = SKB_EXT_ERR(skb);
228 	serr->ee.ee_errno = err;
229 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
230 	serr->ee.ee_type = icmph->icmp6_type;
231 	serr->ee.ee_code = icmph->icmp6_code;
232 	serr->ee.ee_pad = 0;
233 	serr->ee.ee_info = info;
234 	serr->ee.ee_data = 0;
235 	serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
236 				  skb_network_header(skb);
237 	serr->port = port;
238 
239 	__skb_pull(skb, payload - skb->data);
240 	skb_reset_transport_header(skb);
241 
242 	if (sock_queue_err_skb(sk, skb))
243 		kfree_skb(skb);
244 }
245 
246 void ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info)
247 {
248 	struct ipv6_pinfo *np = inet6_sk(sk);
249 	struct sock_exterr_skb *serr;
250 	struct ipv6hdr *iph;
251 	struct sk_buff *skb;
252 
253 	if (!np->recverr)
254 		return;
255 
256 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
257 	if (!skb)
258 		return;
259 
260 	skb->protocol = htons(ETH_P_IPV6);
261 
262 	skb_put(skb, sizeof(struct ipv6hdr));
263 	skb_reset_network_header(skb);
264 	iph = ipv6_hdr(skb);
265 	ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);
266 
267 	serr = SKB_EXT_ERR(skb);
268 	serr->ee.ee_errno = err;
269 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
270 	serr->ee.ee_type = 0;
271 	serr->ee.ee_code = 0;
272 	serr->ee.ee_pad = 0;
273 	serr->ee.ee_info = info;
274 	serr->ee.ee_data = 0;
275 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
276 	serr->port = fl->fl_ip_dport;
277 
278 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
279 	skb_reset_transport_header(skb);
280 
281 	if (sock_queue_err_skb(sk, skb))
282 		kfree_skb(skb);
283 }
284 
285 void ipv6_local_rxpmtu(struct sock *sk, struct flowi *fl, u32 mtu)
286 {
287 	struct ipv6_pinfo *np = inet6_sk(sk);
288 	struct ipv6hdr *iph;
289 	struct sk_buff *skb;
290 	struct ip6_mtuinfo *mtu_info;
291 
292 	if (!np->rxopt.bits.rxpmtu)
293 		return;
294 
295 	skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
296 	if (!skb)
297 		return;
298 
299 	skb_put(skb, sizeof(struct ipv6hdr));
300 	skb_reset_network_header(skb);
301 	iph = ipv6_hdr(skb);
302 	ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);
303 
304 	mtu_info = IP6CBMTU(skb);
305 	if (!mtu_info) {
306 		kfree_skb(skb);
307 		return;
308 	}
309 
310 	mtu_info->ip6m_mtu = mtu;
311 	mtu_info->ip6m_addr.sin6_family = AF_INET6;
312 	mtu_info->ip6m_addr.sin6_port = 0;
313 	mtu_info->ip6m_addr.sin6_flowinfo = 0;
314 	mtu_info->ip6m_addr.sin6_scope_id = fl->oif;
315 	ipv6_addr_copy(&mtu_info->ip6m_addr.sin6_addr, &ipv6_hdr(skb)->daddr);
316 
317 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
318 	skb_reset_transport_header(skb);
319 
320 	skb = xchg(&np->rxpmtu, skb);
321 	kfree_skb(skb);
322 }
323 
324 /*
325  *	Handle MSG_ERRQUEUE
326  */
327 int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
328 {
329 	struct ipv6_pinfo *np = inet6_sk(sk);
330 	struct sock_exterr_skb *serr;
331 	struct sk_buff *skb, *skb2;
332 	struct sockaddr_in6 *sin;
333 	struct {
334 		struct sock_extended_err ee;
335 		struct sockaddr_in6	 offender;
336 	} errhdr;
337 	int err;
338 	int copied;
339 
340 	err = -EAGAIN;
341 	skb = skb_dequeue(&sk->sk_error_queue);
342 	if (skb == NULL)
343 		goto out;
344 
345 	copied = skb->len;
346 	if (copied > len) {
347 		msg->msg_flags |= MSG_TRUNC;
348 		copied = len;
349 	}
350 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
351 	if (err)
352 		goto out_free_skb;
353 
354 	sock_recv_timestamp(msg, sk, skb);
355 
356 	serr = SKB_EXT_ERR(skb);
357 
358 	sin = (struct sockaddr_in6 *)msg->msg_name;
359 	if (sin) {
360 		const unsigned char *nh = skb_network_header(skb);
361 		sin->sin6_family = AF_INET6;
362 		sin->sin6_flowinfo = 0;
363 		sin->sin6_port = serr->port;
364 		sin->sin6_scope_id = 0;
365 		if (skb->protocol == htons(ETH_P_IPV6)) {
366 			ipv6_addr_copy(&sin->sin6_addr,
367 				  (struct in6_addr *)(nh + serr->addr_offset));
368 			if (np->sndflow)
369 				sin->sin6_flowinfo =
370 					(*(__be32 *)(nh + serr->addr_offset - 24) &
371 					 IPV6_FLOWINFO_MASK);
372 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
373 				sin->sin6_scope_id = IP6CB(skb)->iif;
374 		} else {
375 			ipv6_addr_set_v4mapped(*(__be32 *)(nh + serr->addr_offset),
376 					       &sin->sin6_addr);
377 		}
378 	}
379 
380 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
381 	sin = &errhdr.offender;
382 	sin->sin6_family = AF_UNSPEC;
383 	if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
384 		sin->sin6_family = AF_INET6;
385 		sin->sin6_flowinfo = 0;
386 		sin->sin6_scope_id = 0;
387 		if (skb->protocol == htons(ETH_P_IPV6)) {
388 			ipv6_addr_copy(&sin->sin6_addr, &ipv6_hdr(skb)->saddr);
389 			if (np->rxopt.all)
390 				datagram_recv_ctl(sk, msg, skb);
391 			if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
392 				sin->sin6_scope_id = IP6CB(skb)->iif;
393 		} else {
394 			struct inet_sock *inet = inet_sk(sk);
395 
396 			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
397 					       &sin->sin6_addr);
398 			if (inet->cmsg_flags)
399 				ip_cmsg_recv(msg, skb);
400 		}
401 	}
402 
403 	put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);
404 
405 	/* Now we could try to dump offended packet options */
406 
407 	msg->msg_flags |= MSG_ERRQUEUE;
408 	err = copied;
409 
410 	/* Reset and regenerate socket error */
411 	spin_lock_bh(&sk->sk_error_queue.lock);
412 	sk->sk_err = 0;
413 	if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
414 		sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
415 		spin_unlock_bh(&sk->sk_error_queue.lock);
416 		sk->sk_error_report(sk);
417 	} else {
418 		spin_unlock_bh(&sk->sk_error_queue.lock);
419 	}
420 
421 out_free_skb:
422 	kfree_skb(skb);
423 out:
424 	return err;
425 }
426 
427 /*
428  *	Handle IPV6_RECVPATHMTU
429  */
430 int ipv6_recv_rxpmtu(struct sock *sk, struct msghdr *msg, int len)
431 {
432 	struct ipv6_pinfo *np = inet6_sk(sk);
433 	struct sk_buff *skb;
434 	struct sockaddr_in6 *sin;
435 	struct ip6_mtuinfo mtu_info;
436 	int err;
437 	int copied;
438 
439 	err = -EAGAIN;
440 	skb = xchg(&np->rxpmtu, NULL);
441 	if (skb == NULL)
442 		goto out;
443 
444 	copied = skb->len;
445 	if (copied > len) {
446 		msg->msg_flags |= MSG_TRUNC;
447 		copied = len;
448 	}
449 	err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
450 	if (err)
451 		goto out_free_skb;
452 
453 	sock_recv_timestamp(msg, sk, skb);
454 
455 	memcpy(&mtu_info, IP6CBMTU(skb), sizeof(mtu_info));
456 
457 	sin = (struct sockaddr_in6 *)msg->msg_name;
458 	if (sin) {
459 		sin->sin6_family = AF_INET6;
460 		sin->sin6_flowinfo = 0;
461 		sin->sin6_port = 0;
462 		sin->sin6_scope_id = mtu_info.ip6m_addr.sin6_scope_id;
463 		ipv6_addr_copy(&sin->sin6_addr, &mtu_info.ip6m_addr.sin6_addr);
464 	}
465 
466 	put_cmsg(msg, SOL_IPV6, IPV6_PATHMTU, sizeof(mtu_info), &mtu_info);
467 
468 	err = copied;
469 
470 out_free_skb:
471 	kfree_skb(skb);
472 out:
473 	return err;
474 }
475 
476 
477 int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
478 {
479 	struct ipv6_pinfo *np = inet6_sk(sk);
480 	struct inet6_skb_parm *opt = IP6CB(skb);
481 	unsigned char *nh = skb_network_header(skb);
482 
483 	if (np->rxopt.bits.rxinfo) {
484 		struct in6_pktinfo src_info;
485 
486 		src_info.ipi6_ifindex = opt->iif;
487 		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
488 		put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
489 	}
490 
491 	if (np->rxopt.bits.rxhlim) {
492 		int hlim = ipv6_hdr(skb)->hop_limit;
493 		put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
494 	}
495 
496 	if (np->rxopt.bits.rxtclass) {
497 		int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
498 		put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
499 	}
500 
501 	if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
502 		__be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
503 		put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
504 	}
505 
506 	/* HbH is allowed only once */
507 	if (np->rxopt.bits.hopopts && opt->hop) {
508 		u8 *ptr = nh + opt->hop;
509 		put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
510 	}
511 
512 	if (opt->lastopt &&
513 	    (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
514 		/*
515 		 * Silly enough, but we need to reparse in order to
516 		 * report extension headers (except for HbH)
517 		 * in order.
518 		 *
519 		 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
520 		 * (and WILL NOT be) defined because
521 		 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
522 		 */
523 		unsigned int off = sizeof(struct ipv6hdr);
524 		u8 nexthdr = ipv6_hdr(skb)->nexthdr;
525 
526 		while (off <= opt->lastopt) {
527 			unsigned len;
528 			u8 *ptr = nh + off;
529 
530 			switch(nexthdr) {
531 			case IPPROTO_DSTOPTS:
532 				nexthdr = ptr[0];
533 				len = (ptr[1] + 1) << 3;
534 				if (np->rxopt.bits.dstopts)
535 					put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
536 				break;
537 			case IPPROTO_ROUTING:
538 				nexthdr = ptr[0];
539 				len = (ptr[1] + 1) << 3;
540 				if (np->rxopt.bits.srcrt)
541 					put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
542 				break;
543 			case IPPROTO_AH:
544 				nexthdr = ptr[0];
545 				len = (ptr[1] + 2) << 2;
546 				break;
547 			default:
548 				nexthdr = ptr[0];
549 				len = (ptr[1] + 1) << 3;
550 				break;
551 			}
552 
553 			off += len;
554 		}
555 	}
556 
557 	/* socket options in old style */
558 	if (np->rxopt.bits.rxoinfo) {
559 		struct in6_pktinfo src_info;
560 
561 		src_info.ipi6_ifindex = opt->iif;
562 		ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
563 		put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
564 	}
565 	if (np->rxopt.bits.rxohlim) {
566 		int hlim = ipv6_hdr(skb)->hop_limit;
567 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
568 	}
569 	if (np->rxopt.bits.ohopopts && opt->hop) {
570 		u8 *ptr = nh + opt->hop;
571 		put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
572 	}
573 	if (np->rxopt.bits.odstopts && opt->dst0) {
574 		u8 *ptr = nh + opt->dst0;
575 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
576 	}
577 	if (np->rxopt.bits.osrcrt && opt->srcrt) {
578 		struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
579 		put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
580 	}
581 	if (np->rxopt.bits.odstopts && opt->dst1) {
582 		u8 *ptr = nh + opt->dst1;
583 		put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
584 	}
585 	return 0;
586 }
587 
588 int datagram_send_ctl(struct net *net,
589 		      struct msghdr *msg, struct flowi *fl,
590 		      struct ipv6_txoptions *opt,
591 		      int *hlimit, int *tclass, int *dontfrag)
592 {
593 	struct in6_pktinfo *src_info;
594 	struct cmsghdr *cmsg;
595 	struct ipv6_rt_hdr *rthdr;
596 	struct ipv6_opt_hdr *hdr;
597 	int len;
598 	int err = 0;
599 
600 	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
601 		int addr_type;
602 
603 		if (!CMSG_OK(msg, cmsg)) {
604 			err = -EINVAL;
605 			goto exit_f;
606 		}
607 
608 		if (cmsg->cmsg_level != SOL_IPV6)
609 			continue;
610 
611 		switch (cmsg->cmsg_type) {
612 		case IPV6_PKTINFO:
613 		case IPV6_2292PKTINFO:
614 		    {
615 			struct net_device *dev = NULL;
616 
617 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
618 				err = -EINVAL;
619 				goto exit_f;
620 			}
621 
622 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
623 
624 			if (src_info->ipi6_ifindex) {
625 				if (fl->oif && src_info->ipi6_ifindex != fl->oif)
626 					return -EINVAL;
627 				fl->oif = src_info->ipi6_ifindex;
628 			}
629 
630 			addr_type = __ipv6_addr_type(&src_info->ipi6_addr);
631 
632 			rcu_read_lock();
633 			if (fl->oif) {
634 				dev = dev_get_by_index_rcu(net, fl->oif);
635 				if (!dev) {
636 					rcu_read_unlock();
637 					return -ENODEV;
638 				}
639 			} else if (addr_type & IPV6_ADDR_LINKLOCAL) {
640 				rcu_read_unlock();
641 				return -EINVAL;
642 			}
643 
644 			if (addr_type != IPV6_ADDR_ANY) {
645 				int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
646 				if (!ipv6_chk_addr(net, &src_info->ipi6_addr,
647 						   strict ? dev : NULL, 0))
648 					err = -EINVAL;
649 				else
650 					ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
651 			}
652 
653 			rcu_read_unlock();
654 
655 			if (err)
656 				goto exit_f;
657 
658 			break;
659 		    }
660 
661 		case IPV6_FLOWINFO:
662 			if (cmsg->cmsg_len < CMSG_LEN(4)) {
663 				err = -EINVAL;
664 				goto exit_f;
665 			}
666 
667 			if (fl->fl6_flowlabel&IPV6_FLOWINFO_MASK) {
668 				if ((fl->fl6_flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
669 					err = -EINVAL;
670 					goto exit_f;
671 				}
672 			}
673 			fl->fl6_flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
674 			break;
675 
676 		case IPV6_2292HOPOPTS:
677 		case IPV6_HOPOPTS:
678 			if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
679 				err = -EINVAL;
680 				goto exit_f;
681 			}
682 
683 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
684 			len = ((hdr->hdrlen + 1) << 3);
685 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
686 				err = -EINVAL;
687 				goto exit_f;
688 			}
689 			if (!capable(CAP_NET_RAW)) {
690 				err = -EPERM;
691 				goto exit_f;
692 			}
693 			opt->opt_nflen += len;
694 			opt->hopopt = hdr;
695 			break;
696 
697 		case IPV6_2292DSTOPTS:
698 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
699 				err = -EINVAL;
700 				goto exit_f;
701 			}
702 
703 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
704 			len = ((hdr->hdrlen + 1) << 3);
705 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
706 				err = -EINVAL;
707 				goto exit_f;
708 			}
709 			if (!capable(CAP_NET_RAW)) {
710 				err = -EPERM;
711 				goto exit_f;
712 			}
713 			if (opt->dst1opt) {
714 				err = -EINVAL;
715 				goto exit_f;
716 			}
717 			opt->opt_flen += len;
718 			opt->dst1opt = hdr;
719 			break;
720 
721 		case IPV6_DSTOPTS:
722 		case IPV6_RTHDRDSTOPTS:
723 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
724 				err = -EINVAL;
725 				goto exit_f;
726 			}
727 
728 			hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
729 			len = ((hdr->hdrlen + 1) << 3);
730 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
731 				err = -EINVAL;
732 				goto exit_f;
733 			}
734 			if (!capable(CAP_NET_RAW)) {
735 				err = -EPERM;
736 				goto exit_f;
737 			}
738 			if (cmsg->cmsg_type == IPV6_DSTOPTS) {
739 				opt->opt_flen += len;
740 				opt->dst1opt = hdr;
741 			} else {
742 				opt->opt_nflen += len;
743 				opt->dst0opt = hdr;
744 			}
745 			break;
746 
747 		case IPV6_2292RTHDR:
748 		case IPV6_RTHDR:
749 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
750 				err = -EINVAL;
751 				goto exit_f;
752 			}
753 
754 			rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);
755 
756 			switch (rthdr->type) {
757 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
758 			case IPV6_SRCRT_TYPE_2:
759 				if (rthdr->hdrlen != 2 ||
760 				    rthdr->segments_left != 1) {
761 					err = -EINVAL;
762 					goto exit_f;
763 				}
764 				break;
765 #endif
766 			default:
767 				err = -EINVAL;
768 				goto exit_f;
769 			}
770 
771 			len = ((rthdr->hdrlen + 1) << 3);
772 
773 			if (cmsg->cmsg_len < CMSG_LEN(len)) {
774 				err = -EINVAL;
775 				goto exit_f;
776 			}
777 
778 			/* segments left must also match */
779 			if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
780 				err = -EINVAL;
781 				goto exit_f;
782 			}
783 
784 			opt->opt_nflen += len;
785 			opt->srcrt = rthdr;
786 
787 			if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
788 				int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);
789 
790 				opt->opt_nflen += dsthdrlen;
791 				opt->dst0opt = opt->dst1opt;
792 				opt->dst1opt = NULL;
793 				opt->opt_flen -= dsthdrlen;
794 			}
795 
796 			break;
797 
798 		case IPV6_2292HOPLIMIT:
799 		case IPV6_HOPLIMIT:
800 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
801 				err = -EINVAL;
802 				goto exit_f;
803 			}
804 
805 			*hlimit = *(int *)CMSG_DATA(cmsg);
806 			if (*hlimit < -1 || *hlimit > 0xff) {
807 				err = -EINVAL;
808 				goto exit_f;
809 			}
810 
811 			break;
812 
813 		case IPV6_TCLASS:
814 		    {
815 			int tc;
816 
817 			err = -EINVAL;
818 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
819 				goto exit_f;
820 			}
821 
822 			tc = *(int *)CMSG_DATA(cmsg);
823 			if (tc < -1 || tc > 0xff)
824 				goto exit_f;
825 
826 			err = 0;
827 			*tclass = tc;
828 
829 			break;
830 		    }
831 
832 		case IPV6_DONTFRAG:
833 		    {
834 			int df;
835 
836 			err = -EINVAL;
837 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
838 				goto exit_f;
839 			}
840 
841 			df = *(int *)CMSG_DATA(cmsg);
842 			if (df < 0 || df > 1)
843 				goto exit_f;
844 
845 			err = 0;
846 			*dontfrag = df;
847 
848 			break;
849 		    }
850 		default:
851 			LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
852 				       cmsg->cmsg_type);
853 			err = -EINVAL;
854 			goto exit_f;
855 		}
856 	}
857 
858 exit_f:
859 	return err;
860 }
861