xref: /openbmc/linux/net/ipv4/ip_sockglue.c (revision d5e7cafd)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		The IP to API glue.
7  *
8  * Authors:	see ip.c
9  *
10  * Fixes:
11  *		Many		:	Split from ip.c , see ip.c for history.
12  *		Martin Mares	:	TOS setting fixed.
13  *		Alan Cox	:	Fixed a couple of oopses in Martin's
14  *					TOS tweaks.
15  *		Mike McLagan	:	Routing by source
16  */
17 
18 #include <linux/module.h>
19 #include <linux/types.h>
20 #include <linux/mm.h>
21 #include <linux/skbuff.h>
22 #include <linux/ip.h>
23 #include <linux/icmp.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/slab.h>
27 #include <net/sock.h>
28 #include <net/ip.h>
29 #include <net/icmp.h>
30 #include <net/tcp_states.h>
31 #include <linux/udp.h>
32 #include <linux/igmp.h>
33 #include <linux/netfilter.h>
34 #include <linux/route.h>
35 #include <linux/mroute.h>
36 #include <net/inet_ecn.h>
37 #include <net/route.h>
38 #include <net/xfrm.h>
39 #include <net/compat.h>
40 #include <net/checksum.h>
41 #if IS_ENABLED(CONFIG_IPV6)
42 #include <net/transp_v6.h>
43 #endif
44 #include <net/ip_fib.h>
45 
46 #include <linux/errqueue.h>
47 #include <asm/uaccess.h>
48 
49 /*
50  *	SOL_IP control messages.
51  */
52 
53 static void ip_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
54 {
55 	struct in_pktinfo info = *PKTINFO_SKB_CB(skb);
56 
57 	info.ipi_addr.s_addr = ip_hdr(skb)->daddr;
58 
59 	put_cmsg(msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
60 }
61 
62 static void ip_cmsg_recv_ttl(struct msghdr *msg, struct sk_buff *skb)
63 {
64 	int ttl = ip_hdr(skb)->ttl;
65 	put_cmsg(msg, SOL_IP, IP_TTL, sizeof(int), &ttl);
66 }
67 
68 static void ip_cmsg_recv_tos(struct msghdr *msg, struct sk_buff *skb)
69 {
70 	put_cmsg(msg, SOL_IP, IP_TOS, 1, &ip_hdr(skb)->tos);
71 }
72 
73 static void ip_cmsg_recv_opts(struct msghdr *msg, struct sk_buff *skb)
74 {
75 	if (IPCB(skb)->opt.optlen == 0)
76 		return;
77 
78 	put_cmsg(msg, SOL_IP, IP_RECVOPTS, IPCB(skb)->opt.optlen,
79 		 ip_hdr(skb) + 1);
80 }
81 
82 
83 static void ip_cmsg_recv_retopts(struct msghdr *msg, struct sk_buff *skb)
84 {
85 	unsigned char optbuf[sizeof(struct ip_options) + 40];
86 	struct ip_options *opt = (struct ip_options *)optbuf;
87 
88 	if (IPCB(skb)->opt.optlen == 0)
89 		return;
90 
91 	if (ip_options_echo(opt, skb)) {
92 		msg->msg_flags |= MSG_CTRUNC;
93 		return;
94 	}
95 	ip_options_undo(opt);
96 
97 	put_cmsg(msg, SOL_IP, IP_RETOPTS, opt->optlen, opt->__data);
98 }
99 
100 static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
101 				  int offset)
102 {
103 	__wsum csum = skb->csum;
104 
105 	if (skb->ip_summed != CHECKSUM_COMPLETE)
106 		return;
107 
108 	if (offset != 0)
109 		csum = csum_sub(csum, csum_partial(skb->data, offset, 0));
110 
111 	put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
112 }
113 
114 static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
115 {
116 	char *secdata;
117 	u32 seclen, secid;
118 	int err;
119 
120 	err = security_socket_getpeersec_dgram(NULL, skb, &secid);
121 	if (err)
122 		return;
123 
124 	err = security_secid_to_secctx(secid, &secdata, &seclen);
125 	if (err)
126 		return;
127 
128 	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
129 	security_release_secctx(secdata, seclen);
130 }
131 
132 static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
133 {
134 	struct sockaddr_in sin;
135 	const struct iphdr *iph = ip_hdr(skb);
136 	__be16 *ports = (__be16 *)skb_transport_header(skb);
137 
138 	if (skb_transport_offset(skb) + 4 > skb->len)
139 		return;
140 
141 	/* All current transport protocols have the port numbers in the
142 	 * first four bytes of the transport header and this function is
143 	 * written with this assumption in mind.
144 	 */
145 
146 	sin.sin_family = AF_INET;
147 	sin.sin_addr.s_addr = iph->daddr;
148 	sin.sin_port = ports[1];
149 	memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
150 
151 	put_cmsg(msg, SOL_IP, IP_ORIGDSTADDR, sizeof(sin), &sin);
152 }
153 
154 void ip_cmsg_recv_offset(struct msghdr *msg, struct sk_buff *skb,
155 			 int offset)
156 {
157 	struct inet_sock *inet = inet_sk(skb->sk);
158 	unsigned int flags = inet->cmsg_flags;
159 
160 	/* Ordered by supposed usage frequency */
161 	if (flags & IP_CMSG_PKTINFO) {
162 		ip_cmsg_recv_pktinfo(msg, skb);
163 
164 		flags &= ~IP_CMSG_PKTINFO;
165 		if (!flags)
166 			return;
167 	}
168 
169 	if (flags & IP_CMSG_TTL) {
170 		ip_cmsg_recv_ttl(msg, skb);
171 
172 		flags &= ~IP_CMSG_TTL;
173 		if (!flags)
174 			return;
175 	}
176 
177 	if (flags & IP_CMSG_TOS) {
178 		ip_cmsg_recv_tos(msg, skb);
179 
180 		flags &= ~IP_CMSG_TOS;
181 		if (!flags)
182 			return;
183 	}
184 
185 	if (flags & IP_CMSG_RECVOPTS) {
186 		ip_cmsg_recv_opts(msg, skb);
187 
188 		flags &= ~IP_CMSG_RECVOPTS;
189 		if (!flags)
190 			return;
191 	}
192 
193 	if (flags & IP_CMSG_RETOPTS) {
194 		ip_cmsg_recv_retopts(msg, skb);
195 
196 		flags &= ~IP_CMSG_RETOPTS;
197 		if (!flags)
198 			return;
199 	}
200 
201 	if (flags & IP_CMSG_PASSSEC) {
202 		ip_cmsg_recv_security(msg, skb);
203 
204 		flags &= ~IP_CMSG_PASSSEC;
205 		if (!flags)
206 			return;
207 	}
208 
209 	if (flags & IP_CMSG_ORIGDSTADDR) {
210 		ip_cmsg_recv_dstaddr(msg, skb);
211 
212 		flags &= ~IP_CMSG_ORIGDSTADDR;
213 		if (!flags)
214 			return;
215 	}
216 
217 	if (flags & IP_CMSG_CHECKSUM)
218 		ip_cmsg_recv_checksum(msg, skb, offset);
219 }
220 EXPORT_SYMBOL(ip_cmsg_recv_offset);
221 
222 int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc,
223 		 bool allow_ipv6)
224 {
225 	int err, val;
226 	struct cmsghdr *cmsg;
227 
228 	for_each_cmsghdr(cmsg, msg) {
229 		if (!CMSG_OK(msg, cmsg))
230 			return -EINVAL;
231 #if IS_ENABLED(CONFIG_IPV6)
232 		if (allow_ipv6 &&
233 		    cmsg->cmsg_level == SOL_IPV6 &&
234 		    cmsg->cmsg_type == IPV6_PKTINFO) {
235 			struct in6_pktinfo *src_info;
236 
237 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*src_info)))
238 				return -EINVAL;
239 			src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
240 			if (!ipv6_addr_v4mapped(&src_info->ipi6_addr))
241 				return -EINVAL;
242 			ipc->oif = src_info->ipi6_ifindex;
243 			ipc->addr = src_info->ipi6_addr.s6_addr32[3];
244 			continue;
245 		}
246 #endif
247 		if (cmsg->cmsg_level != SOL_IP)
248 			continue;
249 		switch (cmsg->cmsg_type) {
250 		case IP_RETOPTS:
251 			err = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
252 			err = ip_options_get(net, &ipc->opt, CMSG_DATA(cmsg),
253 					     err < 40 ? err : 40);
254 			if (err)
255 				return err;
256 			break;
257 		case IP_PKTINFO:
258 		{
259 			struct in_pktinfo *info;
260 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct in_pktinfo)))
261 				return -EINVAL;
262 			info = (struct in_pktinfo *)CMSG_DATA(cmsg);
263 			ipc->oif = info->ipi_ifindex;
264 			ipc->addr = info->ipi_spec_dst.s_addr;
265 			break;
266 		}
267 		case IP_TTL:
268 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
269 				return -EINVAL;
270 			val = *(int *)CMSG_DATA(cmsg);
271 			if (val < 1 || val > 255)
272 				return -EINVAL;
273 			ipc->ttl = val;
274 			break;
275 		case IP_TOS:
276 			if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
277 				return -EINVAL;
278 			val = *(int *)CMSG_DATA(cmsg);
279 			if (val < 0 || val > 255)
280 				return -EINVAL;
281 			ipc->tos = val;
282 			ipc->priority = rt_tos2priority(ipc->tos);
283 			break;
284 
285 		default:
286 			return -EINVAL;
287 		}
288 	}
289 	return 0;
290 }
291 
292 
293 /* Special input handler for packets caught by router alert option.
294    They are selected only by protocol field, and then processed likely
295    local ones; but only if someone wants them! Otherwise, router
296    not running rsvpd will kill RSVP.
297 
298    It is user level problem, what it will make with them.
299    I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
300    but receiver should be enough clever f.e. to forward mtrace requests,
301    sent to multicast group to reach destination designated router.
302  */
303 struct ip_ra_chain __rcu *ip_ra_chain;
304 static DEFINE_SPINLOCK(ip_ra_lock);
305 
306 
307 static void ip_ra_destroy_rcu(struct rcu_head *head)
308 {
309 	struct ip_ra_chain *ra = container_of(head, struct ip_ra_chain, rcu);
310 
311 	sock_put(ra->saved_sk);
312 	kfree(ra);
313 }
314 
315 int ip_ra_control(struct sock *sk, unsigned char on,
316 		  void (*destructor)(struct sock *))
317 {
318 	struct ip_ra_chain *ra, *new_ra;
319 	struct ip_ra_chain __rcu **rap;
320 
321 	if (sk->sk_type != SOCK_RAW || inet_sk(sk)->inet_num == IPPROTO_RAW)
322 		return -EINVAL;
323 
324 	new_ra = on ? kmalloc(sizeof(*new_ra), GFP_KERNEL) : NULL;
325 
326 	spin_lock_bh(&ip_ra_lock);
327 	for (rap = &ip_ra_chain;
328 	     (ra = rcu_dereference_protected(*rap,
329 			lockdep_is_held(&ip_ra_lock))) != NULL;
330 	     rap = &ra->next) {
331 		if (ra->sk == sk) {
332 			if (on) {
333 				spin_unlock_bh(&ip_ra_lock);
334 				kfree(new_ra);
335 				return -EADDRINUSE;
336 			}
337 			/* dont let ip_call_ra_chain() use sk again */
338 			ra->sk = NULL;
339 			RCU_INIT_POINTER(*rap, ra->next);
340 			spin_unlock_bh(&ip_ra_lock);
341 
342 			if (ra->destructor)
343 				ra->destructor(sk);
344 			/*
345 			 * Delay sock_put(sk) and kfree(ra) after one rcu grace
346 			 * period. This guarantee ip_call_ra_chain() dont need
347 			 * to mess with socket refcounts.
348 			 */
349 			ra->saved_sk = sk;
350 			call_rcu(&ra->rcu, ip_ra_destroy_rcu);
351 			return 0;
352 		}
353 	}
354 	if (new_ra == NULL) {
355 		spin_unlock_bh(&ip_ra_lock);
356 		return -ENOBUFS;
357 	}
358 	new_ra->sk = sk;
359 	new_ra->destructor = destructor;
360 
361 	RCU_INIT_POINTER(new_ra->next, ra);
362 	rcu_assign_pointer(*rap, new_ra);
363 	sock_hold(sk);
364 	spin_unlock_bh(&ip_ra_lock);
365 
366 	return 0;
367 }
368 
369 void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
370 		   __be16 port, u32 info, u8 *payload)
371 {
372 	struct sock_exterr_skb *serr;
373 
374 	skb = skb_clone(skb, GFP_ATOMIC);
375 	if (!skb)
376 		return;
377 
378 	serr = SKB_EXT_ERR(skb);
379 	serr->ee.ee_errno = err;
380 	serr->ee.ee_origin = SO_EE_ORIGIN_ICMP;
381 	serr->ee.ee_type = icmp_hdr(skb)->type;
382 	serr->ee.ee_code = icmp_hdr(skb)->code;
383 	serr->ee.ee_pad = 0;
384 	serr->ee.ee_info = info;
385 	serr->ee.ee_data = 0;
386 	serr->addr_offset = (u8 *)&(((struct iphdr *)(icmp_hdr(skb) + 1))->daddr) -
387 				   skb_network_header(skb);
388 	serr->port = port;
389 
390 	if (skb_pull(skb, payload - skb->data) != NULL) {
391 		skb_reset_transport_header(skb);
392 		if (sock_queue_err_skb(sk, skb) == 0)
393 			return;
394 	}
395 	kfree_skb(skb);
396 }
397 
398 void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 port, u32 info)
399 {
400 	struct inet_sock *inet = inet_sk(sk);
401 	struct sock_exterr_skb *serr;
402 	struct iphdr *iph;
403 	struct sk_buff *skb;
404 
405 	if (!inet->recverr)
406 		return;
407 
408 	skb = alloc_skb(sizeof(struct iphdr), GFP_ATOMIC);
409 	if (!skb)
410 		return;
411 
412 	skb_put(skb, sizeof(struct iphdr));
413 	skb_reset_network_header(skb);
414 	iph = ip_hdr(skb);
415 	iph->daddr = daddr;
416 
417 	serr = SKB_EXT_ERR(skb);
418 	serr->ee.ee_errno = err;
419 	serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
420 	serr->ee.ee_type = 0;
421 	serr->ee.ee_code = 0;
422 	serr->ee.ee_pad = 0;
423 	serr->ee.ee_info = info;
424 	serr->ee.ee_data = 0;
425 	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
426 	serr->port = port;
427 
428 	__skb_pull(skb, skb_tail_pointer(skb) - skb->data);
429 	skb_reset_transport_header(skb);
430 
431 	if (sock_queue_err_skb(sk, skb))
432 		kfree_skb(skb);
433 }
434 
435 /* IPv4 supports cmsg on all imcp errors and some timestamps
436  *
437  * Timestamp code paths do not initialize the fields expected by cmsg:
438  * the PKTINFO fields in skb->cb[]. Fill those in here.
439  */
440 static bool ipv4_datagram_support_cmsg(const struct sock *sk,
441 				       struct sk_buff *skb,
442 				       int ee_origin)
443 {
444 	struct in_pktinfo *info;
445 
446 	if (ee_origin == SO_EE_ORIGIN_ICMP)
447 		return true;
448 
449 	if (ee_origin == SO_EE_ORIGIN_LOCAL)
450 		return false;
451 
452 	/* Support IP_PKTINFO on tstamp packets if requested, to correlate
453 	 * timestamp with egress dev. Not possible for packets without dev
454 	 * or without payload (SOF_TIMESTAMPING_OPT_TSONLY).
455 	 */
456 	if ((!(sk->sk_tsflags & SOF_TIMESTAMPING_OPT_CMSG)) ||
457 	    (!skb->dev))
458 		return false;
459 
460 	info = PKTINFO_SKB_CB(skb);
461 	info->ipi_spec_dst.s_addr = ip_hdr(skb)->saddr;
462 	info->ipi_ifindex = skb->dev->ifindex;
463 	return true;
464 }
465 
466 /*
467  *	Handle MSG_ERRQUEUE
468  */
469 int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
470 {
471 	struct sock_exterr_skb *serr;
472 	struct sk_buff *skb;
473 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
474 	struct {
475 		struct sock_extended_err ee;
476 		struct sockaddr_in	 offender;
477 	} errhdr;
478 	int err;
479 	int copied;
480 
481 	WARN_ON_ONCE(sk->sk_family == AF_INET6);
482 
483 	err = -EAGAIN;
484 	skb = sock_dequeue_err_skb(sk);
485 	if (skb == NULL)
486 		goto out;
487 
488 	copied = skb->len;
489 	if (copied > len) {
490 		msg->msg_flags |= MSG_TRUNC;
491 		copied = len;
492 	}
493 	err = skb_copy_datagram_msg(skb, 0, msg, copied);
494 	if (err)
495 		goto out_free_skb;
496 
497 	sock_recv_timestamp(msg, sk, skb);
498 
499 	serr = SKB_EXT_ERR(skb);
500 
501 	if (sin && serr->port) {
502 		sin->sin_family = AF_INET;
503 		sin->sin_addr.s_addr = *(__be32 *)(skb_network_header(skb) +
504 						   serr->addr_offset);
505 		sin->sin_port = serr->port;
506 		memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
507 		*addr_len = sizeof(*sin);
508 	}
509 
510 	memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
511 	sin = &errhdr.offender;
512 	memset(sin, 0, sizeof(*sin));
513 
514 	if (ipv4_datagram_support_cmsg(sk, skb, serr->ee.ee_origin)) {
515 		sin->sin_family = AF_INET;
516 		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
517 		if (inet_sk(sk)->cmsg_flags)
518 			ip_cmsg_recv(msg, skb);
519 	}
520 
521 	put_cmsg(msg, SOL_IP, IP_RECVERR, sizeof(errhdr), &errhdr);
522 
523 	/* Now we could try to dump offended packet options */
524 
525 	msg->msg_flags |= MSG_ERRQUEUE;
526 	err = copied;
527 
528 out_free_skb:
529 	kfree_skb(skb);
530 out:
531 	return err;
532 }
533 
534 
535 /*
536  *	Socket option code for IP. This is the end of the line after any
537  *	TCP,UDP etc options on an IP socket.
538  */
539 
540 static int do_ip_setsockopt(struct sock *sk, int level,
541 			    int optname, char __user *optval, unsigned int optlen)
542 {
543 	struct inet_sock *inet = inet_sk(sk);
544 	int val = 0, err;
545 
546 	switch (optname) {
547 	case IP_PKTINFO:
548 	case IP_RECVTTL:
549 	case IP_RECVOPTS:
550 	case IP_RECVTOS:
551 	case IP_RETOPTS:
552 	case IP_TOS:
553 	case IP_TTL:
554 	case IP_HDRINCL:
555 	case IP_MTU_DISCOVER:
556 	case IP_RECVERR:
557 	case IP_ROUTER_ALERT:
558 	case IP_FREEBIND:
559 	case IP_PASSSEC:
560 	case IP_TRANSPARENT:
561 	case IP_MINTTL:
562 	case IP_NODEFRAG:
563 	case IP_UNICAST_IF:
564 	case IP_MULTICAST_TTL:
565 	case IP_MULTICAST_ALL:
566 	case IP_MULTICAST_LOOP:
567 	case IP_RECVORIGDSTADDR:
568 	case IP_CHECKSUM:
569 		if (optlen >= sizeof(int)) {
570 			if (get_user(val, (int __user *) optval))
571 				return -EFAULT;
572 		} else if (optlen >= sizeof(char)) {
573 			unsigned char ucval;
574 
575 			if (get_user(ucval, (unsigned char __user *) optval))
576 				return -EFAULT;
577 			val = (int) ucval;
578 		}
579 	}
580 
581 	/* If optlen==0, it is equivalent to val == 0 */
582 
583 	if (ip_mroute_opt(optname))
584 		return ip_mroute_setsockopt(sk, optname, optval, optlen);
585 
586 	err = 0;
587 	lock_sock(sk);
588 
589 	switch (optname) {
590 	case IP_OPTIONS:
591 	{
592 		struct ip_options_rcu *old, *opt = NULL;
593 
594 		if (optlen > 40)
595 			goto e_inval;
596 		err = ip_options_get_from_user(sock_net(sk), &opt,
597 					       optval, optlen);
598 		if (err)
599 			break;
600 		old = rcu_dereference_protected(inet->inet_opt,
601 						sock_owned_by_user(sk));
602 		if (inet->is_icsk) {
603 			struct inet_connection_sock *icsk = inet_csk(sk);
604 #if IS_ENABLED(CONFIG_IPV6)
605 			if (sk->sk_family == PF_INET ||
606 			    (!((1 << sk->sk_state) &
607 			       (TCPF_LISTEN | TCPF_CLOSE)) &&
608 			     inet->inet_daddr != LOOPBACK4_IPV6)) {
609 #endif
610 				if (old)
611 					icsk->icsk_ext_hdr_len -= old->opt.optlen;
612 				if (opt)
613 					icsk->icsk_ext_hdr_len += opt->opt.optlen;
614 				icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie);
615 #if IS_ENABLED(CONFIG_IPV6)
616 			}
617 #endif
618 		}
619 		rcu_assign_pointer(inet->inet_opt, opt);
620 		if (old)
621 			kfree_rcu(old, rcu);
622 		break;
623 	}
624 	case IP_PKTINFO:
625 		if (val)
626 			inet->cmsg_flags |= IP_CMSG_PKTINFO;
627 		else
628 			inet->cmsg_flags &= ~IP_CMSG_PKTINFO;
629 		break;
630 	case IP_RECVTTL:
631 		if (val)
632 			inet->cmsg_flags |=  IP_CMSG_TTL;
633 		else
634 			inet->cmsg_flags &= ~IP_CMSG_TTL;
635 		break;
636 	case IP_RECVTOS:
637 		if (val)
638 			inet->cmsg_flags |=  IP_CMSG_TOS;
639 		else
640 			inet->cmsg_flags &= ~IP_CMSG_TOS;
641 		break;
642 	case IP_RECVOPTS:
643 		if (val)
644 			inet->cmsg_flags |=  IP_CMSG_RECVOPTS;
645 		else
646 			inet->cmsg_flags &= ~IP_CMSG_RECVOPTS;
647 		break;
648 	case IP_RETOPTS:
649 		if (val)
650 			inet->cmsg_flags |= IP_CMSG_RETOPTS;
651 		else
652 			inet->cmsg_flags &= ~IP_CMSG_RETOPTS;
653 		break;
654 	case IP_PASSSEC:
655 		if (val)
656 			inet->cmsg_flags |= IP_CMSG_PASSSEC;
657 		else
658 			inet->cmsg_flags &= ~IP_CMSG_PASSSEC;
659 		break;
660 	case IP_RECVORIGDSTADDR:
661 		if (val)
662 			inet->cmsg_flags |= IP_CMSG_ORIGDSTADDR;
663 		else
664 			inet->cmsg_flags &= ~IP_CMSG_ORIGDSTADDR;
665 		break;
666 	case IP_CHECKSUM:
667 		if (val) {
668 			if (!(inet->cmsg_flags & IP_CMSG_CHECKSUM)) {
669 				inet_inc_convert_csum(sk);
670 				inet->cmsg_flags |= IP_CMSG_CHECKSUM;
671 			}
672 		} else {
673 			if (inet->cmsg_flags & IP_CMSG_CHECKSUM) {
674 				inet_dec_convert_csum(sk);
675 				inet->cmsg_flags &= ~IP_CMSG_CHECKSUM;
676 			}
677 		}
678 		break;
679 	case IP_TOS:	/* This sets both TOS and Precedence */
680 		if (sk->sk_type == SOCK_STREAM) {
681 			val &= ~INET_ECN_MASK;
682 			val |= inet->tos & INET_ECN_MASK;
683 		}
684 		if (inet->tos != val) {
685 			inet->tos = val;
686 			sk->sk_priority = rt_tos2priority(val);
687 			sk_dst_reset(sk);
688 		}
689 		break;
690 	case IP_TTL:
691 		if (optlen < 1)
692 			goto e_inval;
693 		if (val != -1 && (val < 1 || val > 255))
694 			goto e_inval;
695 		inet->uc_ttl = val;
696 		break;
697 	case IP_HDRINCL:
698 		if (sk->sk_type != SOCK_RAW) {
699 			err = -ENOPROTOOPT;
700 			break;
701 		}
702 		inet->hdrincl = val ? 1 : 0;
703 		break;
704 	case IP_NODEFRAG:
705 		if (sk->sk_type != SOCK_RAW) {
706 			err = -ENOPROTOOPT;
707 			break;
708 		}
709 		inet->nodefrag = val ? 1 : 0;
710 		break;
711 	case IP_MTU_DISCOVER:
712 		if (val < IP_PMTUDISC_DONT || val > IP_PMTUDISC_OMIT)
713 			goto e_inval;
714 		inet->pmtudisc = val;
715 		break;
716 	case IP_RECVERR:
717 		inet->recverr = !!val;
718 		if (!val)
719 			skb_queue_purge(&sk->sk_error_queue);
720 		break;
721 	case IP_MULTICAST_TTL:
722 		if (sk->sk_type == SOCK_STREAM)
723 			goto e_inval;
724 		if (optlen < 1)
725 			goto e_inval;
726 		if (val == -1)
727 			val = 1;
728 		if (val < 0 || val > 255)
729 			goto e_inval;
730 		inet->mc_ttl = val;
731 		break;
732 	case IP_MULTICAST_LOOP:
733 		if (optlen < 1)
734 			goto e_inval;
735 		inet->mc_loop = !!val;
736 		break;
737 	case IP_UNICAST_IF:
738 	{
739 		struct net_device *dev = NULL;
740 		int ifindex;
741 
742 		if (optlen != sizeof(int))
743 			goto e_inval;
744 
745 		ifindex = (__force int)ntohl((__force __be32)val);
746 		if (ifindex == 0) {
747 			inet->uc_index = 0;
748 			err = 0;
749 			break;
750 		}
751 
752 		dev = dev_get_by_index(sock_net(sk), ifindex);
753 		err = -EADDRNOTAVAIL;
754 		if (!dev)
755 			break;
756 		dev_put(dev);
757 
758 		err = -EINVAL;
759 		if (sk->sk_bound_dev_if)
760 			break;
761 
762 		inet->uc_index = ifindex;
763 		err = 0;
764 		break;
765 	}
766 	case IP_MULTICAST_IF:
767 	{
768 		struct ip_mreqn mreq;
769 		struct net_device *dev = NULL;
770 
771 		if (sk->sk_type == SOCK_STREAM)
772 			goto e_inval;
773 		/*
774 		 *	Check the arguments are allowable
775 		 */
776 
777 		if (optlen < sizeof(struct in_addr))
778 			goto e_inval;
779 
780 		err = -EFAULT;
781 		if (optlen >= sizeof(struct ip_mreqn)) {
782 			if (copy_from_user(&mreq, optval, sizeof(mreq)))
783 				break;
784 		} else {
785 			memset(&mreq, 0, sizeof(mreq));
786 			if (optlen >= sizeof(struct ip_mreq)) {
787 				if (copy_from_user(&mreq, optval,
788 						   sizeof(struct ip_mreq)))
789 					break;
790 			} else if (optlen >= sizeof(struct in_addr)) {
791 				if (copy_from_user(&mreq.imr_address, optval,
792 						   sizeof(struct in_addr)))
793 					break;
794 			}
795 		}
796 
797 		if (!mreq.imr_ifindex) {
798 			if (mreq.imr_address.s_addr == htonl(INADDR_ANY)) {
799 				inet->mc_index = 0;
800 				inet->mc_addr  = 0;
801 				err = 0;
802 				break;
803 			}
804 			dev = ip_dev_find(sock_net(sk), mreq.imr_address.s_addr);
805 			if (dev)
806 				mreq.imr_ifindex = dev->ifindex;
807 		} else
808 			dev = dev_get_by_index(sock_net(sk), mreq.imr_ifindex);
809 
810 
811 		err = -EADDRNOTAVAIL;
812 		if (!dev)
813 			break;
814 		dev_put(dev);
815 
816 		err = -EINVAL;
817 		if (sk->sk_bound_dev_if &&
818 		    mreq.imr_ifindex != sk->sk_bound_dev_if)
819 			break;
820 
821 		inet->mc_index = mreq.imr_ifindex;
822 		inet->mc_addr  = mreq.imr_address.s_addr;
823 		err = 0;
824 		break;
825 	}
826 
827 	case IP_ADD_MEMBERSHIP:
828 	case IP_DROP_MEMBERSHIP:
829 	{
830 		struct ip_mreqn mreq;
831 
832 		err = -EPROTO;
833 		if (inet_sk(sk)->is_icsk)
834 			break;
835 
836 		if (optlen < sizeof(struct ip_mreq))
837 			goto e_inval;
838 		err = -EFAULT;
839 		if (optlen >= sizeof(struct ip_mreqn)) {
840 			if (copy_from_user(&mreq, optval, sizeof(mreq)))
841 				break;
842 		} else {
843 			memset(&mreq, 0, sizeof(mreq));
844 			if (copy_from_user(&mreq, optval, sizeof(struct ip_mreq)))
845 				break;
846 		}
847 
848 		if (optname == IP_ADD_MEMBERSHIP)
849 			err = ip_mc_join_group(sk, &mreq);
850 		else
851 			err = ip_mc_leave_group(sk, &mreq);
852 		break;
853 	}
854 	case IP_MSFILTER:
855 	{
856 		struct ip_msfilter *msf;
857 
858 		if (optlen < IP_MSFILTER_SIZE(0))
859 			goto e_inval;
860 		if (optlen > sysctl_optmem_max) {
861 			err = -ENOBUFS;
862 			break;
863 		}
864 		msf = kmalloc(optlen, GFP_KERNEL);
865 		if (!msf) {
866 			err = -ENOBUFS;
867 			break;
868 		}
869 		err = -EFAULT;
870 		if (copy_from_user(msf, optval, optlen)) {
871 			kfree(msf);
872 			break;
873 		}
874 		/* numsrc >= (1G-4) overflow in 32 bits */
875 		if (msf->imsf_numsrc >= 0x3ffffffcU ||
876 		    msf->imsf_numsrc > sysctl_igmp_max_msf) {
877 			kfree(msf);
878 			err = -ENOBUFS;
879 			break;
880 		}
881 		if (IP_MSFILTER_SIZE(msf->imsf_numsrc) > optlen) {
882 			kfree(msf);
883 			err = -EINVAL;
884 			break;
885 		}
886 		err = ip_mc_msfilter(sk, msf, 0);
887 		kfree(msf);
888 		break;
889 	}
890 	case IP_BLOCK_SOURCE:
891 	case IP_UNBLOCK_SOURCE:
892 	case IP_ADD_SOURCE_MEMBERSHIP:
893 	case IP_DROP_SOURCE_MEMBERSHIP:
894 	{
895 		struct ip_mreq_source mreqs;
896 		int omode, add;
897 
898 		if (optlen != sizeof(struct ip_mreq_source))
899 			goto e_inval;
900 		if (copy_from_user(&mreqs, optval, sizeof(mreqs))) {
901 			err = -EFAULT;
902 			break;
903 		}
904 		if (optname == IP_BLOCK_SOURCE) {
905 			omode = MCAST_EXCLUDE;
906 			add = 1;
907 		} else if (optname == IP_UNBLOCK_SOURCE) {
908 			omode = MCAST_EXCLUDE;
909 			add = 0;
910 		} else if (optname == IP_ADD_SOURCE_MEMBERSHIP) {
911 			struct ip_mreqn mreq;
912 
913 			mreq.imr_multiaddr.s_addr = mreqs.imr_multiaddr;
914 			mreq.imr_address.s_addr = mreqs.imr_interface;
915 			mreq.imr_ifindex = 0;
916 			err = ip_mc_join_group(sk, &mreq);
917 			if (err && err != -EADDRINUSE)
918 				break;
919 			omode = MCAST_INCLUDE;
920 			add = 1;
921 		} else /* IP_DROP_SOURCE_MEMBERSHIP */ {
922 			omode = MCAST_INCLUDE;
923 			add = 0;
924 		}
925 		err = ip_mc_source(add, omode, sk, &mreqs, 0);
926 		break;
927 	}
928 	case MCAST_JOIN_GROUP:
929 	case MCAST_LEAVE_GROUP:
930 	{
931 		struct group_req greq;
932 		struct sockaddr_in *psin;
933 		struct ip_mreqn mreq;
934 
935 		if (optlen < sizeof(struct group_req))
936 			goto e_inval;
937 		err = -EFAULT;
938 		if (copy_from_user(&greq, optval, sizeof(greq)))
939 			break;
940 		psin = (struct sockaddr_in *)&greq.gr_group;
941 		if (psin->sin_family != AF_INET)
942 			goto e_inval;
943 		memset(&mreq, 0, sizeof(mreq));
944 		mreq.imr_multiaddr = psin->sin_addr;
945 		mreq.imr_ifindex = greq.gr_interface;
946 
947 		if (optname == MCAST_JOIN_GROUP)
948 			err = ip_mc_join_group(sk, &mreq);
949 		else
950 			err = ip_mc_leave_group(sk, &mreq);
951 		break;
952 	}
953 	case MCAST_JOIN_SOURCE_GROUP:
954 	case MCAST_LEAVE_SOURCE_GROUP:
955 	case MCAST_BLOCK_SOURCE:
956 	case MCAST_UNBLOCK_SOURCE:
957 	{
958 		struct group_source_req greqs;
959 		struct ip_mreq_source mreqs;
960 		struct sockaddr_in *psin;
961 		int omode, add;
962 
963 		if (optlen != sizeof(struct group_source_req))
964 			goto e_inval;
965 		if (copy_from_user(&greqs, optval, sizeof(greqs))) {
966 			err = -EFAULT;
967 			break;
968 		}
969 		if (greqs.gsr_group.ss_family != AF_INET ||
970 		    greqs.gsr_source.ss_family != AF_INET) {
971 			err = -EADDRNOTAVAIL;
972 			break;
973 		}
974 		psin = (struct sockaddr_in *)&greqs.gsr_group;
975 		mreqs.imr_multiaddr = psin->sin_addr.s_addr;
976 		psin = (struct sockaddr_in *)&greqs.gsr_source;
977 		mreqs.imr_sourceaddr = psin->sin_addr.s_addr;
978 		mreqs.imr_interface = 0; /* use index for mc_source */
979 
980 		if (optname == MCAST_BLOCK_SOURCE) {
981 			omode = MCAST_EXCLUDE;
982 			add = 1;
983 		} else if (optname == MCAST_UNBLOCK_SOURCE) {
984 			omode = MCAST_EXCLUDE;
985 			add = 0;
986 		} else if (optname == MCAST_JOIN_SOURCE_GROUP) {
987 			struct ip_mreqn mreq;
988 
989 			psin = (struct sockaddr_in *)&greqs.gsr_group;
990 			mreq.imr_multiaddr = psin->sin_addr;
991 			mreq.imr_address.s_addr = 0;
992 			mreq.imr_ifindex = greqs.gsr_interface;
993 			err = ip_mc_join_group(sk, &mreq);
994 			if (err && err != -EADDRINUSE)
995 				break;
996 			greqs.gsr_interface = mreq.imr_ifindex;
997 			omode = MCAST_INCLUDE;
998 			add = 1;
999 		} else /* MCAST_LEAVE_SOURCE_GROUP */ {
1000 			omode = MCAST_INCLUDE;
1001 			add = 0;
1002 		}
1003 		err = ip_mc_source(add, omode, sk, &mreqs,
1004 				   greqs.gsr_interface);
1005 		break;
1006 	}
1007 	case MCAST_MSFILTER:
1008 	{
1009 		struct sockaddr_in *psin;
1010 		struct ip_msfilter *msf = NULL;
1011 		struct group_filter *gsf = NULL;
1012 		int msize, i, ifindex;
1013 
1014 		if (optlen < GROUP_FILTER_SIZE(0))
1015 			goto e_inval;
1016 		if (optlen > sysctl_optmem_max) {
1017 			err = -ENOBUFS;
1018 			break;
1019 		}
1020 		gsf = kmalloc(optlen, GFP_KERNEL);
1021 		if (!gsf) {
1022 			err = -ENOBUFS;
1023 			break;
1024 		}
1025 		err = -EFAULT;
1026 		if (copy_from_user(gsf, optval, optlen))
1027 			goto mc_msf_out;
1028 
1029 		/* numsrc >= (4G-140)/128 overflow in 32 bits */
1030 		if (gsf->gf_numsrc >= 0x1ffffff ||
1031 		    gsf->gf_numsrc > sysctl_igmp_max_msf) {
1032 			err = -ENOBUFS;
1033 			goto mc_msf_out;
1034 		}
1035 		if (GROUP_FILTER_SIZE(gsf->gf_numsrc) > optlen) {
1036 			err = -EINVAL;
1037 			goto mc_msf_out;
1038 		}
1039 		msize = IP_MSFILTER_SIZE(gsf->gf_numsrc);
1040 		msf = kmalloc(msize, GFP_KERNEL);
1041 		if (!msf) {
1042 			err = -ENOBUFS;
1043 			goto mc_msf_out;
1044 		}
1045 		ifindex = gsf->gf_interface;
1046 		psin = (struct sockaddr_in *)&gsf->gf_group;
1047 		if (psin->sin_family != AF_INET) {
1048 			err = -EADDRNOTAVAIL;
1049 			goto mc_msf_out;
1050 		}
1051 		msf->imsf_multiaddr = psin->sin_addr.s_addr;
1052 		msf->imsf_interface = 0;
1053 		msf->imsf_fmode = gsf->gf_fmode;
1054 		msf->imsf_numsrc = gsf->gf_numsrc;
1055 		err = -EADDRNOTAVAIL;
1056 		for (i = 0; i < gsf->gf_numsrc; ++i) {
1057 			psin = (struct sockaddr_in *)&gsf->gf_slist[i];
1058 
1059 			if (psin->sin_family != AF_INET)
1060 				goto mc_msf_out;
1061 			msf->imsf_slist[i] = psin->sin_addr.s_addr;
1062 		}
1063 		kfree(gsf);
1064 		gsf = NULL;
1065 
1066 		err = ip_mc_msfilter(sk, msf, ifindex);
1067 mc_msf_out:
1068 		kfree(msf);
1069 		kfree(gsf);
1070 		break;
1071 	}
1072 	case IP_MULTICAST_ALL:
1073 		if (optlen < 1)
1074 			goto e_inval;
1075 		if (val != 0 && val != 1)
1076 			goto e_inval;
1077 		inet->mc_all = val;
1078 		break;
1079 	case IP_ROUTER_ALERT:
1080 		err = ip_ra_control(sk, val ? 1 : 0, NULL);
1081 		break;
1082 
1083 	case IP_FREEBIND:
1084 		if (optlen < 1)
1085 			goto e_inval;
1086 		inet->freebind = !!val;
1087 		break;
1088 
1089 	case IP_IPSEC_POLICY:
1090 	case IP_XFRM_POLICY:
1091 		err = -EPERM;
1092 		if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1093 			break;
1094 		err = xfrm_user_policy(sk, optname, optval, optlen);
1095 		break;
1096 
1097 	case IP_TRANSPARENT:
1098 		if (!!val && !ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) &&
1099 		    !ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
1100 			err = -EPERM;
1101 			break;
1102 		}
1103 		if (optlen < 1)
1104 			goto e_inval;
1105 		inet->transparent = !!val;
1106 		break;
1107 
1108 	case IP_MINTTL:
1109 		if (optlen < 1)
1110 			goto e_inval;
1111 		if (val < 0 || val > 255)
1112 			goto e_inval;
1113 		inet->min_ttl = val;
1114 		break;
1115 
1116 	default:
1117 		err = -ENOPROTOOPT;
1118 		break;
1119 	}
1120 	release_sock(sk);
1121 	return err;
1122 
1123 e_inval:
1124 	release_sock(sk);
1125 	return -EINVAL;
1126 }
1127 
1128 /**
1129  * ipv4_pktinfo_prepare - transfer some info from rtable to skb
1130  * @sk: socket
1131  * @skb: buffer
1132  *
1133  * To support IP_CMSG_PKTINFO option, we store rt_iif and specific
1134  * destination in skb->cb[] before dst drop.
1135  * This way, receiver doesn't make cache line misses to read rtable.
1136  */
1137 void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb)
1138 {
1139 	struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb);
1140 	bool prepare = (inet_sk(sk)->cmsg_flags & IP_CMSG_PKTINFO) ||
1141 		       ipv6_sk_rxinfo(sk);
1142 
1143 	if (prepare && skb_rtable(skb)) {
1144 		pktinfo->ipi_ifindex = inet_iif(skb);
1145 		pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
1146 	} else {
1147 		pktinfo->ipi_ifindex = 0;
1148 		pktinfo->ipi_spec_dst.s_addr = 0;
1149 	}
1150 	skb_dst_drop(skb);
1151 }
1152 
1153 int ip_setsockopt(struct sock *sk, int level,
1154 		int optname, char __user *optval, unsigned int optlen)
1155 {
1156 	int err;
1157 
1158 	if (level != SOL_IP)
1159 		return -ENOPROTOOPT;
1160 
1161 	err = do_ip_setsockopt(sk, level, optname, optval, optlen);
1162 #ifdef CONFIG_NETFILTER
1163 	/* we need to exclude all possible ENOPROTOOPTs except default case */
1164 	if (err == -ENOPROTOOPT && optname != IP_HDRINCL &&
1165 			optname != IP_IPSEC_POLICY &&
1166 			optname != IP_XFRM_POLICY &&
1167 			!ip_mroute_opt(optname)) {
1168 		lock_sock(sk);
1169 		err = nf_setsockopt(sk, PF_INET, optname, optval, optlen);
1170 		release_sock(sk);
1171 	}
1172 #endif
1173 	return err;
1174 }
1175 EXPORT_SYMBOL(ip_setsockopt);
1176 
1177 #ifdef CONFIG_COMPAT
1178 int compat_ip_setsockopt(struct sock *sk, int level, int optname,
1179 			 char __user *optval, unsigned int optlen)
1180 {
1181 	int err;
1182 
1183 	if (level != SOL_IP)
1184 		return -ENOPROTOOPT;
1185 
1186 	if (optname >= MCAST_JOIN_GROUP && optname <= MCAST_MSFILTER)
1187 		return compat_mc_setsockopt(sk, level, optname, optval, optlen,
1188 			ip_setsockopt);
1189 
1190 	err = do_ip_setsockopt(sk, level, optname, optval, optlen);
1191 #ifdef CONFIG_NETFILTER
1192 	/* we need to exclude all possible ENOPROTOOPTs except default case */
1193 	if (err == -ENOPROTOOPT && optname != IP_HDRINCL &&
1194 			optname != IP_IPSEC_POLICY &&
1195 			optname != IP_XFRM_POLICY &&
1196 			!ip_mroute_opt(optname)) {
1197 		lock_sock(sk);
1198 		err = compat_nf_setsockopt(sk, PF_INET, optname,
1199 					   optval, optlen);
1200 		release_sock(sk);
1201 	}
1202 #endif
1203 	return err;
1204 }
1205 EXPORT_SYMBOL(compat_ip_setsockopt);
1206 #endif
1207 
1208 /*
1209  *	Get the options. Note for future reference. The GET of IP options gets
1210  *	the _received_ ones. The set sets the _sent_ ones.
1211  */
1212 
1213 static int do_ip_getsockopt(struct sock *sk, int level, int optname,
1214 			    char __user *optval, int __user *optlen, unsigned int flags)
1215 {
1216 	struct inet_sock *inet = inet_sk(sk);
1217 	int val;
1218 	int len;
1219 
1220 	if (level != SOL_IP)
1221 		return -EOPNOTSUPP;
1222 
1223 	if (ip_mroute_opt(optname))
1224 		return ip_mroute_getsockopt(sk, optname, optval, optlen);
1225 
1226 	if (get_user(len, optlen))
1227 		return -EFAULT;
1228 	if (len < 0)
1229 		return -EINVAL;
1230 
1231 	lock_sock(sk);
1232 
1233 	switch (optname) {
1234 	case IP_OPTIONS:
1235 	{
1236 		unsigned char optbuf[sizeof(struct ip_options)+40];
1237 		struct ip_options *opt = (struct ip_options *)optbuf;
1238 		struct ip_options_rcu *inet_opt;
1239 
1240 		inet_opt = rcu_dereference_protected(inet->inet_opt,
1241 						     sock_owned_by_user(sk));
1242 		opt->optlen = 0;
1243 		if (inet_opt)
1244 			memcpy(optbuf, &inet_opt->opt,
1245 			       sizeof(struct ip_options) +
1246 			       inet_opt->opt.optlen);
1247 		release_sock(sk);
1248 
1249 		if (opt->optlen == 0)
1250 			return put_user(0, optlen);
1251 
1252 		ip_options_undo(opt);
1253 
1254 		len = min_t(unsigned int, len, opt->optlen);
1255 		if (put_user(len, optlen))
1256 			return -EFAULT;
1257 		if (copy_to_user(optval, opt->__data, len))
1258 			return -EFAULT;
1259 		return 0;
1260 	}
1261 	case IP_PKTINFO:
1262 		val = (inet->cmsg_flags & IP_CMSG_PKTINFO) != 0;
1263 		break;
1264 	case IP_RECVTTL:
1265 		val = (inet->cmsg_flags & IP_CMSG_TTL) != 0;
1266 		break;
1267 	case IP_RECVTOS:
1268 		val = (inet->cmsg_flags & IP_CMSG_TOS) != 0;
1269 		break;
1270 	case IP_RECVOPTS:
1271 		val = (inet->cmsg_flags & IP_CMSG_RECVOPTS) != 0;
1272 		break;
1273 	case IP_RETOPTS:
1274 		val = (inet->cmsg_flags & IP_CMSG_RETOPTS) != 0;
1275 		break;
1276 	case IP_PASSSEC:
1277 		val = (inet->cmsg_flags & IP_CMSG_PASSSEC) != 0;
1278 		break;
1279 	case IP_RECVORIGDSTADDR:
1280 		val = (inet->cmsg_flags & IP_CMSG_ORIGDSTADDR) != 0;
1281 		break;
1282 	case IP_CHECKSUM:
1283 		val = (inet->cmsg_flags & IP_CMSG_CHECKSUM) != 0;
1284 		break;
1285 	case IP_TOS:
1286 		val = inet->tos;
1287 		break;
1288 	case IP_TTL:
1289 		val = (inet->uc_ttl == -1 ?
1290 		       sysctl_ip_default_ttl :
1291 		       inet->uc_ttl);
1292 		break;
1293 	case IP_HDRINCL:
1294 		val = inet->hdrincl;
1295 		break;
1296 	case IP_NODEFRAG:
1297 		val = inet->nodefrag;
1298 		break;
1299 	case IP_MTU_DISCOVER:
1300 		val = inet->pmtudisc;
1301 		break;
1302 	case IP_MTU:
1303 	{
1304 		struct dst_entry *dst;
1305 		val = 0;
1306 		dst = sk_dst_get(sk);
1307 		if (dst) {
1308 			val = dst_mtu(dst);
1309 			dst_release(dst);
1310 		}
1311 		if (!val) {
1312 			release_sock(sk);
1313 			return -ENOTCONN;
1314 		}
1315 		break;
1316 	}
1317 	case IP_RECVERR:
1318 		val = inet->recverr;
1319 		break;
1320 	case IP_MULTICAST_TTL:
1321 		val = inet->mc_ttl;
1322 		break;
1323 	case IP_MULTICAST_LOOP:
1324 		val = inet->mc_loop;
1325 		break;
1326 	case IP_UNICAST_IF:
1327 		val = (__force int)htonl((__u32) inet->uc_index);
1328 		break;
1329 	case IP_MULTICAST_IF:
1330 	{
1331 		struct in_addr addr;
1332 		len = min_t(unsigned int, len, sizeof(struct in_addr));
1333 		addr.s_addr = inet->mc_addr;
1334 		release_sock(sk);
1335 
1336 		if (put_user(len, optlen))
1337 			return -EFAULT;
1338 		if (copy_to_user(optval, &addr, len))
1339 			return -EFAULT;
1340 		return 0;
1341 	}
1342 	case IP_MSFILTER:
1343 	{
1344 		struct ip_msfilter msf;
1345 		int err;
1346 
1347 		if (len < IP_MSFILTER_SIZE(0)) {
1348 			release_sock(sk);
1349 			return -EINVAL;
1350 		}
1351 		if (copy_from_user(&msf, optval, IP_MSFILTER_SIZE(0))) {
1352 			release_sock(sk);
1353 			return -EFAULT;
1354 		}
1355 		err = ip_mc_msfget(sk, &msf,
1356 				   (struct ip_msfilter __user *)optval, optlen);
1357 		release_sock(sk);
1358 		return err;
1359 	}
1360 	case MCAST_MSFILTER:
1361 	{
1362 		struct group_filter gsf;
1363 		int err;
1364 
1365 		if (len < GROUP_FILTER_SIZE(0)) {
1366 			release_sock(sk);
1367 			return -EINVAL;
1368 		}
1369 		if (copy_from_user(&gsf, optval, GROUP_FILTER_SIZE(0))) {
1370 			release_sock(sk);
1371 			return -EFAULT;
1372 		}
1373 		err = ip_mc_gsfget(sk, &gsf,
1374 				   (struct group_filter __user *)optval,
1375 				   optlen);
1376 		release_sock(sk);
1377 		return err;
1378 	}
1379 	case IP_MULTICAST_ALL:
1380 		val = inet->mc_all;
1381 		break;
1382 	case IP_PKTOPTIONS:
1383 	{
1384 		struct msghdr msg;
1385 
1386 		release_sock(sk);
1387 
1388 		if (sk->sk_type != SOCK_STREAM)
1389 			return -ENOPROTOOPT;
1390 
1391 		msg.msg_control = (__force void *) optval;
1392 		msg.msg_controllen = len;
1393 		msg.msg_flags = flags;
1394 
1395 		if (inet->cmsg_flags & IP_CMSG_PKTINFO) {
1396 			struct in_pktinfo info;
1397 
1398 			info.ipi_addr.s_addr = inet->inet_rcv_saddr;
1399 			info.ipi_spec_dst.s_addr = inet->inet_rcv_saddr;
1400 			info.ipi_ifindex = inet->mc_index;
1401 			put_cmsg(&msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
1402 		}
1403 		if (inet->cmsg_flags & IP_CMSG_TTL) {
1404 			int hlim = inet->mc_ttl;
1405 			put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
1406 		}
1407 		if (inet->cmsg_flags & IP_CMSG_TOS) {
1408 			int tos = inet->rcv_tos;
1409 			put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
1410 		}
1411 		len -= msg.msg_controllen;
1412 		return put_user(len, optlen);
1413 	}
1414 	case IP_FREEBIND:
1415 		val = inet->freebind;
1416 		break;
1417 	case IP_TRANSPARENT:
1418 		val = inet->transparent;
1419 		break;
1420 	case IP_MINTTL:
1421 		val = inet->min_ttl;
1422 		break;
1423 	default:
1424 		release_sock(sk);
1425 		return -ENOPROTOOPT;
1426 	}
1427 	release_sock(sk);
1428 
1429 	if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) {
1430 		unsigned char ucval = (unsigned char)val;
1431 		len = 1;
1432 		if (put_user(len, optlen))
1433 			return -EFAULT;
1434 		if (copy_to_user(optval, &ucval, 1))
1435 			return -EFAULT;
1436 	} else {
1437 		len = min_t(unsigned int, sizeof(int), len);
1438 		if (put_user(len, optlen))
1439 			return -EFAULT;
1440 		if (copy_to_user(optval, &val, len))
1441 			return -EFAULT;
1442 	}
1443 	return 0;
1444 }
1445 
1446 int ip_getsockopt(struct sock *sk, int level,
1447 		  int optname, char __user *optval, int __user *optlen)
1448 {
1449 	int err;
1450 
1451 	err = do_ip_getsockopt(sk, level, optname, optval, optlen, 0);
1452 #ifdef CONFIG_NETFILTER
1453 	/* we need to exclude all possible ENOPROTOOPTs except default case */
1454 	if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS &&
1455 			!ip_mroute_opt(optname)) {
1456 		int len;
1457 
1458 		if (get_user(len, optlen))
1459 			return -EFAULT;
1460 
1461 		lock_sock(sk);
1462 		err = nf_getsockopt(sk, PF_INET, optname, optval,
1463 				&len);
1464 		release_sock(sk);
1465 		if (err >= 0)
1466 			err = put_user(len, optlen);
1467 		return err;
1468 	}
1469 #endif
1470 	return err;
1471 }
1472 EXPORT_SYMBOL(ip_getsockopt);
1473 
1474 #ifdef CONFIG_COMPAT
1475 int compat_ip_getsockopt(struct sock *sk, int level, int optname,
1476 			 char __user *optval, int __user *optlen)
1477 {
1478 	int err;
1479 
1480 	if (optname == MCAST_MSFILTER)
1481 		return compat_mc_getsockopt(sk, level, optname, optval, optlen,
1482 			ip_getsockopt);
1483 
1484 	err = do_ip_getsockopt(sk, level, optname, optval, optlen,
1485 		MSG_CMSG_COMPAT);
1486 
1487 #ifdef CONFIG_NETFILTER
1488 	/* we need to exclude all possible ENOPROTOOPTs except default case */
1489 	if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS &&
1490 			!ip_mroute_opt(optname)) {
1491 		int len;
1492 
1493 		if (get_user(len, optlen))
1494 			return -EFAULT;
1495 
1496 		lock_sock(sk);
1497 		err = compat_nf_getsockopt(sk, PF_INET, optname, optval, &len);
1498 		release_sock(sk);
1499 		if (err >= 0)
1500 			err = put_user(len, optlen);
1501 		return err;
1502 	}
1503 #endif
1504 	return err;
1505 }
1506 EXPORT_SYMBOL(compat_ip_getsockopt);
1507 #endif
1508