xref: /freebsd/sys/netinet/ip_input.c (revision 9f23cbd6cae82fd77edfad7173432fa8dccd0a95)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include "opt_bootp.h"
38 #include "opt_inet.h"
39 #include "opt_ipstealth.h"
40 #include "opt_ipsec.h"
41 #include "opt_route.h"
42 #include "opt_rss.h"
43 #include "opt_sctp.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/hhook.h>
48 #include <sys/mbuf.h>
49 #include <sys/malloc.h>
50 #include <sys/domain.h>
51 #include <sys/protosw.h>
52 #include <sys/socket.h>
53 #include <sys/time.h>
54 #include <sys/kernel.h>
55 #include <sys/lock.h>
56 #include <sys/rmlock.h>
57 #include <sys/rwlock.h>
58 #include <sys/sdt.h>
59 #include <sys/syslog.h>
60 #include <sys/sysctl.h>
61 
62 #include <net/if.h>
63 #include <net/if_types.h>
64 #include <net/if_var.h>
65 #include <net/if_dl.h>
66 #include <net/if_private.h>
67 #include <net/pfil.h>
68 #include <net/route.h>
69 #include <net/route/nhop.h>
70 #include <net/netisr.h>
71 #include <net/rss_config.h>
72 #include <net/vnet.h>
73 
74 #include <netinet/in.h>
75 #include <netinet/in_kdtrace.h>
76 #include <netinet/in_systm.h>
77 #include <netinet/in_var.h>
78 #include <netinet/ip.h>
79 #include <netinet/in_fib.h>
80 #include <netinet/in_pcb.h>
81 #include <netinet/ip_var.h>
82 #include <netinet/ip_encap.h>
83 #include <netinet/ip_fw.h>
84 #include <netinet/ip_icmp.h>
85 #include <netinet/igmp_var.h>
86 #include <netinet/ip_options.h>
87 #include <machine/in_cksum.h>
88 #include <netinet/ip_carp.h>
89 #include <netinet/in_rss.h>
90 #ifdef SCTP
91 #include <netinet/sctp_var.h>
92 #endif
93 
94 #include <netipsec/ipsec_support.h>
95 
96 #include <sys/socketvar.h>
97 
98 #include <security/mac/mac_framework.h>
99 
100 #ifdef CTASSERT
101 CTASSERT(sizeof(struct ip) == 20);
102 #endif
103 
104 /* IP reassembly functions are defined in ip_reass.c. */
105 extern void ipreass_init(void);
106 extern void ipreass_vnet_init(void);
107 #ifdef VIMAGE
108 extern void ipreass_destroy(void);
109 #endif
110 
111 VNET_DEFINE(int, rsvp_on);
112 
113 VNET_DEFINE(int, ipforwarding);
114 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_VNET | CTLFLAG_RW,
115     &VNET_NAME(ipforwarding), 0,
116     "Enable IP forwarding between interfaces");
117 
118 /*
119  * Respond with an ICMP host redirect when we forward a packet out of
120  * the same interface on which it was received.  See RFC 792.
121  */
122 VNET_DEFINE(int, ipsendredirects) = 1;
123 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_VNET | CTLFLAG_RW,
124     &VNET_NAME(ipsendredirects), 0,
125     "Enable sending IP redirects");
126 
127 VNET_DEFINE_STATIC(bool, ip_strong_es) = false;
128 #define	V_ip_strong_es	VNET(ip_strong_es)
129 SYSCTL_BOOL(_net_inet_ip, OID_AUTO, rfc1122_strong_es,
130     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_strong_es), false,
131     "Packet's IP destination address must match address on arrival interface");
132 
133 VNET_DEFINE_STATIC(bool, ip_sav) = true;
134 #define	V_ip_sav	VNET(ip_sav)
135 SYSCTL_BOOL(_net_inet_ip, OID_AUTO, source_address_validation,
136     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_sav), true,
137     "Drop incoming packets with source address that is a local address");
138 
139 /* Packet filter hooks */
140 VNET_DEFINE(pfil_head_t, inet_pfil_head);
141 VNET_DEFINE(pfil_head_t, inet_local_pfil_head);
142 
143 static struct netisr_handler ip_nh = {
144 	.nh_name = "ip",
145 	.nh_handler = ip_input,
146 	.nh_proto = NETISR_IP,
147 #ifdef	RSS
148 	.nh_m2cpuid = rss_soft_m2cpuid_v4,
149 	.nh_policy = NETISR_POLICY_CPU,
150 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
151 #else
152 	.nh_policy = NETISR_POLICY_FLOW,
153 #endif
154 };
155 
156 #ifdef	RSS
157 /*
158  * Directly dispatched frames are currently assumed
159  * to have a flowid already calculated.
160  *
161  * It should likely have something that assert it
162  * actually has valid flow details.
163  */
164 static struct netisr_handler ip_direct_nh = {
165 	.nh_name = "ip_direct",
166 	.nh_handler = ip_direct_input,
167 	.nh_proto = NETISR_IP_DIRECT,
168 	.nh_m2cpuid = rss_soft_m2cpuid_v4,
169 	.nh_policy = NETISR_POLICY_CPU,
170 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
171 };
172 #endif
173 
174 ipproto_input_t		*ip_protox[IPPROTO_MAX] = {
175 			    [0 ... IPPROTO_MAX - 1] = rip_input };
176 ipproto_ctlinput_t	*ip_ctlprotox[IPPROTO_MAX] = {
177 			    [0 ... IPPROTO_MAX - 1] = rip_ctlinput };
178 
179 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead);  /* first inet address */
180 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table  */
181 VNET_DEFINE(u_long, in_ifaddrhmask);		/* mask for hash table */
182 
183 /* Make sure it is safe to use hashinit(9) on CK_LIST. */
184 CTASSERT(sizeof(struct in_ifaddrhashhead) == sizeof(LIST_HEAD(, in_addr)));
185 
186 #ifdef IPCTL_DEFMTU
187 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
188     &ip_mtu, 0, "Default MTU");
189 #endif
190 
191 #ifdef IPSTEALTH
192 VNET_DEFINE(int, ipstealth);
193 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_VNET | CTLFLAG_RW,
194     &VNET_NAME(ipstealth), 0,
195     "IP stealth mode, no TTL decrementation on forwarding");
196 #endif
197 
198 /*
199  * IP statistics are stored in the "array" of counter(9)s.
200  */
201 VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat);
202 VNET_PCPUSTAT_SYSINIT(ipstat);
203 SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat,
204     "IP statistics (struct ipstat, netinet/ip_var.h)");
205 
206 #ifdef VIMAGE
207 VNET_PCPUSTAT_SYSUNINIT(ipstat);
208 #endif /* VIMAGE */
209 
210 /*
211  * Kernel module interface for updating ipstat.  The argument is an index
212  * into ipstat treated as an array.
213  */
214 void
215 kmod_ipstat_inc(int statnum)
216 {
217 
218 	counter_u64_add(VNET(ipstat)[statnum], 1);
219 }
220 
221 void
222 kmod_ipstat_dec(int statnum)
223 {
224 
225 	counter_u64_add(VNET(ipstat)[statnum], -1);
226 }
227 
228 static int
229 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
230 {
231 	int error, qlimit;
232 
233 	netisr_getqlimit(&ip_nh, &qlimit);
234 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
235 	if (error || !req->newptr)
236 		return (error);
237 	if (qlimit < 1)
238 		return (EINVAL);
239 	return (netisr_setqlimit(&ip_nh, qlimit));
240 }
241 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
242     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
243     sysctl_netinet_intr_queue_maxlen, "I",
244     "Maximum size of the IP input queue");
245 
246 static int
247 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
248 {
249 	u_int64_t qdrops_long;
250 	int error, qdrops;
251 
252 	netisr_getqdrops(&ip_nh, &qdrops_long);
253 	qdrops = qdrops_long;
254 	error = sysctl_handle_int(oidp, &qdrops, 0, req);
255 	if (error || !req->newptr)
256 		return (error);
257 	if (qdrops != 0)
258 		return (EINVAL);
259 	netisr_clearqdrops(&ip_nh);
260 	return (0);
261 }
262 
263 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
264     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
265     0, 0, sysctl_netinet_intr_queue_drops, "I",
266     "Number of packets dropped from the IP input queue");
267 
268 #ifdef	RSS
269 static int
270 sysctl_netinet_intr_direct_queue_maxlen(SYSCTL_HANDLER_ARGS)
271 {
272 	int error, qlimit;
273 
274 	netisr_getqlimit(&ip_direct_nh, &qlimit);
275 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
276 	if (error || !req->newptr)
277 		return (error);
278 	if (qlimit < 1)
279 		return (EINVAL);
280 	return (netisr_setqlimit(&ip_direct_nh, qlimit));
281 }
282 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRDQMAXLEN, intr_direct_queue_maxlen,
283     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
284     0, 0, sysctl_netinet_intr_direct_queue_maxlen,
285     "I", "Maximum size of the IP direct input queue");
286 
287 static int
288 sysctl_netinet_intr_direct_queue_drops(SYSCTL_HANDLER_ARGS)
289 {
290 	u_int64_t qdrops_long;
291 	int error, qdrops;
292 
293 	netisr_getqdrops(&ip_direct_nh, &qdrops_long);
294 	qdrops = qdrops_long;
295 	error = sysctl_handle_int(oidp, &qdrops, 0, req);
296 	if (error || !req->newptr)
297 		return (error);
298 	if (qdrops != 0)
299 		return (EINVAL);
300 	netisr_clearqdrops(&ip_direct_nh);
301 	return (0);
302 }
303 
304 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRDQDROPS, intr_direct_queue_drops,
305     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
306     sysctl_netinet_intr_direct_queue_drops, "I",
307     "Number of packets dropped from the IP direct input queue");
308 #endif	/* RSS */
309 
310 /*
311  * IP initialization: fill in IP protocol switch table.
312  * All protocols not implemented in kernel go to raw IP protocol handler.
313  */
314 static void
315 ip_vnet_init(void *arg __unused)
316 {
317 	struct pfil_head_args args;
318 
319 	CK_STAILQ_INIT(&V_in_ifaddrhead);
320 	V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
321 
322 	/* Initialize IP reassembly queue. */
323 	ipreass_vnet_init();
324 
325 	/* Initialize packet filter hooks. */
326 	args.pa_version = PFIL_VERSION;
327 	args.pa_flags = PFIL_IN | PFIL_OUT;
328 	args.pa_type = PFIL_TYPE_IP4;
329 	args.pa_headname = PFIL_INET_NAME;
330 	V_inet_pfil_head = pfil_head_register(&args);
331 
332 	args.pa_flags = PFIL_OUT;
333 	args.pa_headname = PFIL_INET_LOCAL_NAME;
334 	V_inet_local_pfil_head = pfil_head_register(&args);
335 
336 	if (hhook_head_register(HHOOK_TYPE_IPSEC_IN, AF_INET,
337 	    &V_ipsec_hhh_in[HHOOK_IPSEC_INET],
338 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
339 		printf("%s: WARNING: unable to register input helper hook\n",
340 		    __func__);
341 	if (hhook_head_register(HHOOK_TYPE_IPSEC_OUT, AF_INET,
342 	    &V_ipsec_hhh_out[HHOOK_IPSEC_INET],
343 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
344 		printf("%s: WARNING: unable to register output helper hook\n",
345 		    __func__);
346 
347 #ifdef VIMAGE
348 	netisr_register_vnet(&ip_nh);
349 #ifdef	RSS
350 	netisr_register_vnet(&ip_direct_nh);
351 #endif
352 #endif
353 }
354 VNET_SYSINIT(ip_vnet_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
355     ip_vnet_init, NULL);
356 
357 static void
358 ip_init(const void *unused __unused)
359 {
360 
361 	ipreass_init();
362 
363 	/*
364 	 * Register statically compiled protocols, that are unlikely to
365 	 * ever become dynamic.
366 	 */
367 	IPPROTO_REGISTER(IPPROTO_ICMP, icmp_input, NULL);
368 	IPPROTO_REGISTER(IPPROTO_IGMP, igmp_input, NULL);
369 	IPPROTO_REGISTER(IPPROTO_RSVP, rsvp_input, NULL);
370 	IPPROTO_REGISTER(IPPROTO_IPV4, encap4_input, NULL);
371 	IPPROTO_REGISTER(IPPROTO_MOBILE, encap4_input, NULL);
372 	IPPROTO_REGISTER(IPPROTO_ETHERIP, encap4_input, NULL);
373 	IPPROTO_REGISTER(IPPROTO_GRE, encap4_input, NULL);
374 	IPPROTO_REGISTER(IPPROTO_IPV6, encap4_input, NULL);
375 	IPPROTO_REGISTER(IPPROTO_PIM, encap4_input, NULL);
376 #ifdef SCTP	/* XXX: has a loadable & static version */
377 	IPPROTO_REGISTER(IPPROTO_SCTP, sctp_input, sctp_ctlinput);
378 #endif
379 
380 	netisr_register(&ip_nh);
381 #ifdef	RSS
382 	netisr_register(&ip_direct_nh);
383 #endif
384 }
385 SYSINIT(ip_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip_init, NULL);
386 
387 #ifdef VIMAGE
388 static void
389 ip_destroy(void *unused __unused)
390 {
391 	int error;
392 
393 #ifdef	RSS
394 	netisr_unregister_vnet(&ip_direct_nh);
395 #endif
396 	netisr_unregister_vnet(&ip_nh);
397 
398 	pfil_head_unregister(V_inet_pfil_head);
399 	error = hhook_head_deregister(V_ipsec_hhh_in[HHOOK_IPSEC_INET]);
400 	if (error != 0) {
401 		printf("%s: WARNING: unable to deregister input helper hook "
402 		    "type HHOOK_TYPE_IPSEC_IN, id HHOOK_IPSEC_INET: "
403 		    "error %d returned\n", __func__, error);
404 	}
405 	error = hhook_head_deregister(V_ipsec_hhh_out[HHOOK_IPSEC_INET]);
406 	if (error != 0) {
407 		printf("%s: WARNING: unable to deregister output helper hook "
408 		    "type HHOOK_TYPE_IPSEC_OUT, id HHOOK_IPSEC_INET: "
409 		    "error %d returned\n", __func__, error);
410 	}
411 
412 	/* Remove the IPv4 addresses from all interfaces. */
413 	in_ifscrub_all();
414 
415 	/* Make sure the IPv4 routes are gone as well. */
416 	rib_flush_routes_family(AF_INET);
417 
418 	/* Destroy IP reassembly queue. */
419 	ipreass_destroy();
420 
421 	/* Cleanup in_ifaddr hash table; should be empty. */
422 	hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
423 }
424 
425 VNET_SYSUNINIT(ip, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip_destroy, NULL);
426 #endif
427 
428 #ifdef	RSS
429 /*
430  * IP direct input routine.
431  *
432  * This is called when reinjecting completed fragments where
433  * all of the previous checking and book-keeping has been done.
434  */
435 void
436 ip_direct_input(struct mbuf *m)
437 {
438 	struct ip *ip;
439 	int hlen;
440 
441 	ip = mtod(m, struct ip *);
442 	hlen = ip->ip_hl << 2;
443 
444 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
445 	if (IPSEC_ENABLED(ipv4)) {
446 		if (IPSEC_INPUT(ipv4, m, hlen, ip->ip_p) != 0)
447 			return;
448 	}
449 #endif /* IPSEC */
450 	IPSTAT_INC(ips_delivered);
451 	ip_protox[ip->ip_p](&m, &hlen, ip->ip_p);
452 }
453 #endif
454 
455 /*
456  * Ip input routine.  Checksum and byte swap header.  If fragmented
457  * try to reassemble.  Process options.  Pass to next level.
458  */
459 void
460 ip_input(struct mbuf *m)
461 {
462 	struct ip *ip = NULL;
463 	struct in_ifaddr *ia = NULL;
464 	struct ifaddr *ifa;
465 	struct ifnet *ifp;
466 	int hlen = 0;
467 	uint16_t sum, ip_len;
468 	int dchg = 0;				/* dest changed after fw */
469 	struct in_addr odst;			/* original dst address */
470 	bool strong_es;
471 
472 	M_ASSERTPKTHDR(m);
473 	NET_EPOCH_ASSERT();
474 
475 	if (m->m_flags & M_FASTFWD_OURS) {
476 		m->m_flags &= ~M_FASTFWD_OURS;
477 		/* Set up some basics that will be used later. */
478 		ip = mtod(m, struct ip *);
479 		hlen = ip->ip_hl << 2;
480 		ip_len = ntohs(ip->ip_len);
481 		goto ours;
482 	}
483 
484 	IPSTAT_INC(ips_total);
485 
486 	if (__predict_false(m->m_pkthdr.len < sizeof(struct ip)))
487 		goto tooshort;
488 
489 	if (m->m_len < sizeof(struct ip)) {
490 		m = m_pullup(m, sizeof(struct ip));
491 		if (__predict_false(m == NULL)) {
492 			IPSTAT_INC(ips_toosmall);
493 			return;
494 		}
495 	}
496 	ip = mtod(m, struct ip *);
497 
498 	if (__predict_false(ip->ip_v != IPVERSION)) {
499 		IPSTAT_INC(ips_badvers);
500 		goto bad;
501 	}
502 
503 	hlen = ip->ip_hl << 2;
504 	if (__predict_false(hlen < sizeof(struct ip))) {	/* minimum header length */
505 		IPSTAT_INC(ips_badhlen);
506 		goto bad;
507 	}
508 	if (hlen > m->m_len) {
509 		m = m_pullup(m, hlen);
510 		if (__predict_false(m == NULL)) {
511 			IPSTAT_INC(ips_badhlen);
512 			return;
513 		}
514 		ip = mtod(m, struct ip *);
515 	}
516 
517 	IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL);
518 
519 	/* IN_LOOPBACK must not appear on the wire - RFC1122 */
520 	ifp = m->m_pkthdr.rcvif;
521 	if (IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
522 	    IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) {
523 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
524 			IPSTAT_INC(ips_badaddr);
525 			goto bad;
526 		}
527 	}
528 	/* The unspecified address can appear only as a src address - RFC1122 */
529 	if (__predict_false(ntohl(ip->ip_dst.s_addr) == INADDR_ANY)) {
530 		IPSTAT_INC(ips_badaddr);
531 		goto bad;
532 	}
533 
534 	if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
535 		sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
536 	} else {
537 		if (hlen == sizeof(struct ip)) {
538 			sum = in_cksum_hdr(ip);
539 		} else {
540 			sum = in_cksum(m, hlen);
541 		}
542 	}
543 	if (__predict_false(sum)) {
544 		IPSTAT_INC(ips_badsum);
545 		goto bad;
546 	}
547 
548 	ip_len = ntohs(ip->ip_len);
549 	if (__predict_false(ip_len < hlen)) {
550 		IPSTAT_INC(ips_badlen);
551 		goto bad;
552 	}
553 
554 	/*
555 	 * Check that the amount of data in the buffers
556 	 * is as at least much as the IP header would have us expect.
557 	 * Trim mbufs if longer than we expect.
558 	 * Drop packet if shorter than we expect.
559 	 */
560 	if (__predict_false(m->m_pkthdr.len < ip_len)) {
561 tooshort:
562 		IPSTAT_INC(ips_tooshort);
563 		goto bad;
564 	}
565 	if (m->m_pkthdr.len > ip_len) {
566 		if (m->m_len == m->m_pkthdr.len) {
567 			m->m_len = ip_len;
568 			m->m_pkthdr.len = ip_len;
569 		} else
570 			m_adj(m, ip_len - m->m_pkthdr.len);
571 	}
572 
573 	/*
574 	 * Try to forward the packet, but if we fail continue.
575 	 * ip_tryforward() may generate redirects these days.
576 	 * XXX the logic below falling through to normal processing
577 	 * if redirects are required should be revisited as well.
578 	 * ip_tryforward() does inbound and outbound packet firewall
579 	 * processing. If firewall has decided that destination becomes
580 	 * our local address, it sets M_FASTFWD_OURS flag. In this
581 	 * case skip another inbound firewall processing and update
582 	 * ip pointer.
583 	 */
584 	if (V_ipforwarding != 0
585 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
586 	    && (!IPSEC_ENABLED(ipv4) ||
587 	    IPSEC_CAPS(ipv4, m, IPSEC_CAP_OPERABLE) == 0)
588 #endif
589 	    ) {
590 		/*
591 		 * ip_dooptions() was run so we can ignore the source route (or
592 		 * any IP options case) case for redirects in ip_tryforward().
593 		 */
594 		if ((m = ip_tryforward(m)) == NULL)
595 			return;
596 		if (m->m_flags & M_FASTFWD_OURS) {
597 			m->m_flags &= ~M_FASTFWD_OURS;
598 			ip = mtod(m, struct ip *);
599 			goto ours;
600 		}
601 	}
602 
603 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
604 	/*
605 	 * Bypass packet filtering for packets previously handled by IPsec.
606 	 */
607 	if (IPSEC_ENABLED(ipv4) &&
608 	    IPSEC_CAPS(ipv4, m, IPSEC_CAP_BYPASS_FILTER) != 0)
609 			goto passin;
610 #endif
611 
612 	/*
613 	 * Run through list of hooks for input packets.
614 	 *
615 	 * NB: Beware of the destination address changing (e.g.
616 	 *     by NAT rewriting).  When this happens, tell
617 	 *     ip_forward to do the right thing.
618 	 */
619 
620 	/* Jump over all PFIL processing if hooks are not active. */
621 	if (!PFIL_HOOKED_IN(V_inet_pfil_head))
622 		goto passin;
623 
624 	odst = ip->ip_dst;
625 	if (pfil_mbuf_in(V_inet_pfil_head, &m, ifp, NULL) !=
626 	    PFIL_PASS)
627 		return;
628 	if (m == NULL)			/* consumed by filter */
629 		return;
630 
631 	ip = mtod(m, struct ip *);
632 	dchg = (odst.s_addr != ip->ip_dst.s_addr);
633 
634 	if (m->m_flags & M_FASTFWD_OURS) {
635 		m->m_flags &= ~M_FASTFWD_OURS;
636 		goto ours;
637 	}
638 	if (m->m_flags & M_IP_NEXTHOP) {
639 		if (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) {
640 			/*
641 			 * Directly ship the packet on.  This allows
642 			 * forwarding packets originally destined to us
643 			 * to some other directly connected host.
644 			 */
645 			ip_forward(m, 1);
646 			return;
647 		}
648 	}
649 passin:
650 
651 	/*
652 	 * Process options and, if not destined for us,
653 	 * ship it on.  ip_dooptions returns 1 when an
654 	 * error was detected (causing an icmp message
655 	 * to be sent and the original packet to be freed).
656 	 */
657 	if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
658 		return;
659 
660         /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
661          * matter if it is destined to another node, or whether it is
662          * a multicast one, RSVP wants it! and prevents it from being forwarded
663          * anywhere else. Also checks if the rsvp daemon is running before
664 	 * grabbing the packet.
665          */
666 	if (ip->ip_p == IPPROTO_RSVP && V_rsvp_on)
667 		goto ours;
668 
669 	/*
670 	 * Check our list of addresses, to see if the packet is for us.
671 	 * If we don't have any addresses, assume any unicast packet
672 	 * we receive might be for us (and let the upper layers deal
673 	 * with it).
674 	 */
675 	if (CK_STAILQ_EMPTY(&V_in_ifaddrhead) &&
676 	    (m->m_flags & (M_MCAST|M_BCAST)) == 0)
677 		goto ours;
678 
679 	/*
680 	 * Enable a consistency check between the destination address
681 	 * and the arrival interface for a unicast packet (the RFC 1122
682 	 * strong ES model) with a list of additional predicates:
683 	 * - if IP forwarding is disabled
684 	 * - the packet is not locally generated
685 	 * - the packet is not subject to 'ipfw fwd'
686 	 * - Interface is not running CARP. If the packet got here, we already
687 	 *   checked it with carp_iamatch() and carp_forus().
688 	 */
689 	strong_es = V_ip_strong_es && (V_ipforwarding == 0) &&
690 	    ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
691 	    ifp->if_carp == NULL && (dchg == 0);
692 
693 	/*
694 	 * Check for exact addresses in the hash bucket.
695 	 */
696 	CK_LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
697 		if (IA_SIN(ia)->sin_addr.s_addr != ip->ip_dst.s_addr)
698 			continue;
699 
700 		/*
701 		 * net.inet.ip.rfc1122_strong_es: the address matches, verify
702 		 * that the packet arrived via the correct interface.
703 		 */
704 		if (__predict_false(strong_es && ia->ia_ifp != ifp)) {
705 			IPSTAT_INC(ips_badaddr);
706 			goto bad;
707 		}
708 
709 		/*
710 		 * net.inet.ip.source_address_validation: drop incoming
711 		 * packets that pretend to be ours.
712 		 */
713 		if (V_ip_sav && !(ifp->if_flags & IFF_LOOPBACK) &&
714 		    __predict_false(in_localip_fib(ip->ip_src, ifp->if_fib))) {
715 			IPSTAT_INC(ips_badaddr);
716 			goto bad;
717 		}
718 
719 		counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
720 		counter_u64_add(ia->ia_ifa.ifa_ibytes, m->m_pkthdr.len);
721 		goto ours;
722 	}
723 
724 	/*
725 	 * Check for broadcast addresses.
726 	 *
727 	 * Only accept broadcast packets that arrive via the matching
728 	 * interface.  Reception of forwarded directed broadcasts would
729 	 * be handled via ip_forward() and ether_output() with the loopback
730 	 * into the stack for SIMPLEX interfaces handled by ether_output().
731 	 */
732 	if (ifp->if_flags & IFF_BROADCAST) {
733 		CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
734 			if (ifa->ifa_addr->sa_family != AF_INET)
735 				continue;
736 			ia = ifatoia(ifa);
737 			if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
738 			    ip->ip_dst.s_addr) {
739 				counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
740 				counter_u64_add(ia->ia_ifa.ifa_ibytes,
741 				    m->m_pkthdr.len);
742 				goto ours;
743 			}
744 #ifdef BOOTP_COMPAT
745 			if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
746 				counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
747 				counter_u64_add(ia->ia_ifa.ifa_ibytes,
748 				    m->m_pkthdr.len);
749 				goto ours;
750 			}
751 #endif
752 		}
753 		ia = NULL;
754 	}
755 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
756 		/*
757 		 * RFC 3927 2.7: Do not forward multicast packets from
758 		 * IN_LINKLOCAL.
759 		 */
760 		if (V_ip_mrouter && !IN_LINKLOCAL(ntohl(ip->ip_src.s_addr))) {
761 			/*
762 			 * If we are acting as a multicast router, all
763 			 * incoming multicast packets are passed to the
764 			 * kernel-level multicast forwarding function.
765 			 * The packet is returned (relatively) intact; if
766 			 * ip_mforward() returns a non-zero value, the packet
767 			 * must be discarded, else it may be accepted below.
768 			 */
769 			if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
770 				IPSTAT_INC(ips_cantforward);
771 				m_freem(m);
772 				return;
773 			}
774 
775 			/*
776 			 * The process-level routing daemon needs to receive
777 			 * all multicast IGMP packets, whether or not this
778 			 * host belongs to their destination groups.
779 			 */
780 			if (ip->ip_p == IPPROTO_IGMP) {
781 				goto ours;
782 			}
783 			IPSTAT_INC(ips_forward);
784 		}
785 		/*
786 		 * Assume the packet is for us, to avoid prematurely taking
787 		 * a lock on the in_multi hash. Protocols must perform
788 		 * their own filtering and update statistics accordingly.
789 		 */
790 		goto ours;
791 	}
792 	if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
793 		goto ours;
794 	if (ip->ip_dst.s_addr == INADDR_ANY)
795 		goto ours;
796 	/* RFC 3927 2.7: Do not forward packets to or from IN_LINKLOCAL. */
797 	if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) ||
798 	    IN_LINKLOCAL(ntohl(ip->ip_src.s_addr))) {
799 		IPSTAT_INC(ips_cantforward);
800 		m_freem(m);
801 		return;
802 	}
803 
804 	/*
805 	 * Not for us; forward if possible and desirable.
806 	 */
807 	if (V_ipforwarding == 0) {
808 		IPSTAT_INC(ips_cantforward);
809 		m_freem(m);
810 	} else {
811 		ip_forward(m, dchg);
812 	}
813 	return;
814 
815 ours:
816 #ifdef IPSTEALTH
817 	/*
818 	 * IPSTEALTH: Process non-routing options only
819 	 * if the packet is destined for us.
820 	 */
821 	if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1))
822 		return;
823 #endif /* IPSTEALTH */
824 
825 	/*
826 	 * We are going to ship the packet to the local protocol stack. Call the
827 	 * filter again for this 'output' action, allowing redirect-like rules
828 	 * to adjust the source address.
829 	 */
830 	if (PFIL_HOOKED_OUT(V_inet_local_pfil_head)) {
831 		if (pfil_mbuf_out(V_inet_local_pfil_head, &m, V_loif, NULL) !=
832 		    PFIL_PASS)
833 			return;
834 		if (m == NULL)			/* consumed by filter */
835 			return;
836 		ip = mtod(m, struct ip *);
837 	}
838 
839 	/*
840 	 * Attempt reassembly; if it succeeds, proceed.
841 	 * ip_reass() will return a different mbuf.
842 	 */
843 	if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
844 		/* XXXGL: shouldn't we save & set m_flags? */
845 		m = ip_reass(m);
846 		if (m == NULL)
847 			return;
848 		ip = mtod(m, struct ip *);
849 		/* Get the header length of the reassembled packet */
850 		hlen = ip->ip_hl << 2;
851 	}
852 
853 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
854 	if (IPSEC_ENABLED(ipv4)) {
855 		if (IPSEC_INPUT(ipv4, m, hlen, ip->ip_p) != 0)
856 			return;
857 	}
858 #endif /* IPSEC */
859 
860 	/*
861 	 * Switch out to protocol's input routine.
862 	 */
863 	IPSTAT_INC(ips_delivered);
864 
865 	ip_protox[ip->ip_p](&m, &hlen, ip->ip_p);
866 	return;
867 bad:
868 	m_freem(m);
869 }
870 
871 int
872 ipproto_register(uint8_t proto, ipproto_input_t input, ipproto_ctlinput_t ctl)
873 {
874 
875 	MPASS(proto > 0);
876 
877 	/*
878 	 * The protocol slot must not be occupied by another protocol
879 	 * already.  An index pointing to rip_input() is unused.
880 	 */
881 	if (ip_protox[proto] == rip_input) {
882 		ip_protox[proto] = input;
883 		ip_ctlprotox[proto] = ctl;
884 		return (0);
885 	} else
886 		return (EEXIST);
887 }
888 
889 int
890 ipproto_unregister(uint8_t proto)
891 {
892 
893 	MPASS(proto > 0);
894 
895 	if (ip_protox[proto] != rip_input) {
896 		ip_protox[proto] = rip_input;
897 		ip_ctlprotox[proto] = rip_ctlinput;
898 		return (0);
899 	} else
900 		return (ENOENT);
901 }
902 
903 /*
904  * Forward a packet.  If some error occurs return the sender
905  * an icmp packet.  Note we can't always generate a meaningful
906  * icmp message because icmp doesn't have a large enough repertoire
907  * of codes and types.
908  *
909  * If not forwarding, just drop the packet.  This could be confusing
910  * if ipforwarding was zero but some routing protocol was advancing
911  * us as a gateway to somewhere.  However, we must let the routing
912  * protocol deal with that.
913  *
914  * The srcrt parameter indicates whether the packet is being forwarded
915  * via a source route.
916  */
917 void
918 ip_forward(struct mbuf *m, int srcrt)
919 {
920 	struct ip *ip = mtod(m, struct ip *);
921 	struct in_ifaddr *ia;
922 	struct mbuf *mcopy;
923 	struct sockaddr_in *sin;
924 	struct in_addr dest;
925 	struct route ro;
926 	uint32_t flowid;
927 	int error, type = 0, code = 0, mtu = 0;
928 
929 	NET_EPOCH_ASSERT();
930 
931 	if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
932 		IPSTAT_INC(ips_cantforward);
933 		m_freem(m);
934 		return;
935 	}
936 	if (
937 #ifdef IPSTEALTH
938 	    V_ipstealth == 0 &&
939 #endif
940 	    ip->ip_ttl <= IPTTLDEC) {
941 		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, 0);
942 		return;
943 	}
944 
945 	bzero(&ro, sizeof(ro));
946 	sin = (struct sockaddr_in *)&ro.ro_dst;
947 	sin->sin_family = AF_INET;
948 	sin->sin_len = sizeof(*sin);
949 	sin->sin_addr = ip->ip_dst;
950 	flowid = m->m_pkthdr.flowid;
951 	ro.ro_nh = fib4_lookup(M_GETFIB(m), ip->ip_dst, 0, NHR_REF, flowid);
952 	if (ro.ro_nh != NULL) {
953 		ia = ifatoia(ro.ro_nh->nh_ifa);
954 	} else
955 		ia = NULL;
956 	/*
957 	 * Save the IP header and at most 8 bytes of the payload,
958 	 * in case we need to generate an ICMP message to the src.
959 	 *
960 	 * XXX this can be optimized a lot by saving the data in a local
961 	 * buffer on the stack (72 bytes at most), and only allocating the
962 	 * mbuf if really necessary. The vast majority of the packets
963 	 * are forwarded without having to send an ICMP back (either
964 	 * because unnecessary, or because rate limited), so we are
965 	 * really we are wasting a lot of work here.
966 	 *
967 	 * We don't use m_copym() because it might return a reference
968 	 * to a shared cluster. Both this function and ip_output()
969 	 * assume exclusive access to the IP header in `m', so any
970 	 * data in a cluster may change before we reach icmp_error().
971 	 */
972 	mcopy = m_gethdr(M_NOWAIT, m->m_type);
973 	if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) {
974 		/*
975 		 * It's probably ok if the pkthdr dup fails (because
976 		 * the deep copy of the tag chain failed), but for now
977 		 * be conservative and just discard the copy since
978 		 * code below may some day want the tags.
979 		 */
980 		m_free(mcopy);
981 		mcopy = NULL;
982 	}
983 	if (mcopy != NULL) {
984 		mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy));
985 		mcopy->m_pkthdr.len = mcopy->m_len;
986 		m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
987 	}
988 #ifdef IPSTEALTH
989 	if (V_ipstealth == 0)
990 #endif
991 		ip->ip_ttl -= IPTTLDEC;
992 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
993 	if (IPSEC_ENABLED(ipv4)) {
994 		if ((error = IPSEC_FORWARD(ipv4, m)) != 0) {
995 			/* mbuf consumed by IPsec */
996 			RO_NHFREE(&ro);
997 			m_freem(mcopy);
998 			if (error != EINPROGRESS)
999 				IPSTAT_INC(ips_cantforward);
1000 			return;
1001 		}
1002 		/* No IPsec processing required */
1003 	}
1004 #endif /* IPSEC */
1005 	/*
1006 	 * If forwarding packet using same interface that it came in on,
1007 	 * perhaps should send a redirect to sender to shortcut a hop.
1008 	 * Only send redirect if source is sending directly to us,
1009 	 * and if packet was not source routed (or has any options).
1010 	 * Also, don't send redirect if forwarding using a default route
1011 	 * or a route modified by a redirect.
1012 	 */
1013 	dest.s_addr = 0;
1014 	if (!srcrt && V_ipsendredirects &&
1015 	    ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
1016 		struct nhop_object *nh;
1017 
1018 		nh = ro.ro_nh;
1019 
1020 		if (nh != NULL && ((nh->nh_flags & (NHF_REDIRECT|NHF_DEFAULT)) == 0)) {
1021 			struct in_ifaddr *nh_ia = (struct in_ifaddr *)(nh->nh_ifa);
1022 			u_long src = ntohl(ip->ip_src.s_addr);
1023 
1024 			if (nh_ia != NULL &&
1025 			    (src & nh_ia->ia_subnetmask) == nh_ia->ia_subnet) {
1026 				/* Router requirements says to only send host redirects */
1027 				type = ICMP_REDIRECT;
1028 				code = ICMP_REDIRECT_HOST;
1029 				if (nh->nh_flags & NHF_GATEWAY) {
1030 				    if (nh->gw_sa.sa_family == AF_INET)
1031 					dest.s_addr = nh->gw4_sa.sin_addr.s_addr;
1032 				    else /* Do not redirect in case gw is AF_INET6 */
1033 					type = 0;
1034 				} else
1035 					dest.s_addr = ip->ip_dst.s_addr;
1036 			}
1037 		}
1038 	}
1039 
1040 	error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
1041 
1042 	if (error == EMSGSIZE && ro.ro_nh)
1043 		mtu = ro.ro_nh->nh_mtu;
1044 	RO_NHFREE(&ro);
1045 
1046 	if (error)
1047 		IPSTAT_INC(ips_cantforward);
1048 	else {
1049 		IPSTAT_INC(ips_forward);
1050 		if (type)
1051 			IPSTAT_INC(ips_redirectsent);
1052 		else {
1053 			if (mcopy)
1054 				m_freem(mcopy);
1055 			return;
1056 		}
1057 	}
1058 	if (mcopy == NULL)
1059 		return;
1060 
1061 	switch (error) {
1062 	case 0:				/* forwarded, but need redirect */
1063 		/* type, code set above */
1064 		break;
1065 
1066 	case ENETUNREACH:
1067 	case EHOSTUNREACH:
1068 	case ENETDOWN:
1069 	case EHOSTDOWN:
1070 	default:
1071 		type = ICMP_UNREACH;
1072 		code = ICMP_UNREACH_HOST;
1073 		break;
1074 
1075 	case EMSGSIZE:
1076 		type = ICMP_UNREACH;
1077 		code = ICMP_UNREACH_NEEDFRAG;
1078 		/*
1079 		 * If the MTU was set before make sure we are below the
1080 		 * interface MTU.
1081 		 * If the MTU wasn't set before use the interface mtu or
1082 		 * fall back to the next smaller mtu step compared to the
1083 		 * current packet size.
1084 		 */
1085 		if (mtu != 0) {
1086 			if (ia != NULL)
1087 				mtu = min(mtu, ia->ia_ifp->if_mtu);
1088 		} else {
1089 			if (ia != NULL)
1090 				mtu = ia->ia_ifp->if_mtu;
1091 			else
1092 				mtu = ip_next_mtu(ntohs(ip->ip_len), 0);
1093 		}
1094 		IPSTAT_INC(ips_cantfrag);
1095 		break;
1096 
1097 	case ENOBUFS:
1098 	case EACCES:			/* ipfw denied packet */
1099 		m_freem(mcopy);
1100 		return;
1101 	}
1102 	icmp_error(mcopy, type, code, dest.s_addr, mtu);
1103 }
1104 
1105 #define	CHECK_SO_CT(sp, ct) \
1106     (((sp->so_options & SO_TIMESTAMP) && (sp->so_ts_clock == ct)) ? 1 : 0)
1107 
1108 void
1109 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1110     struct mbuf *m)
1111 {
1112 	bool stamped;
1113 
1114 	stamped = false;
1115 	if ((inp->inp_socket->so_options & SO_BINTIME) ||
1116 	    CHECK_SO_CT(inp->inp_socket, SO_TS_BINTIME)) {
1117 		struct bintime boottimebin, bt;
1118 		struct timespec ts1;
1119 
1120 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1121 		    M_TSTMP)) {
1122 			mbuf_tstmp2timespec(m, &ts1);
1123 			timespec2bintime(&ts1, &bt);
1124 			getboottimebin(&boottimebin);
1125 			bintime_add(&bt, &boottimebin);
1126 		} else {
1127 			bintime(&bt);
1128 		}
1129 		*mp = sbcreatecontrol(&bt, sizeof(bt), SCM_BINTIME,
1130 		    SOL_SOCKET, M_NOWAIT);
1131 		if (*mp != NULL) {
1132 			mp = &(*mp)->m_next;
1133 			stamped = true;
1134 		}
1135 	}
1136 	if (CHECK_SO_CT(inp->inp_socket, SO_TS_REALTIME_MICRO)) {
1137 		struct bintime boottimebin, bt1;
1138 		struct timespec ts1;
1139 		struct timeval tv;
1140 
1141 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1142 		    M_TSTMP)) {
1143 			mbuf_tstmp2timespec(m, &ts1);
1144 			timespec2bintime(&ts1, &bt1);
1145 			getboottimebin(&boottimebin);
1146 			bintime_add(&bt1, &boottimebin);
1147 			bintime2timeval(&bt1, &tv);
1148 		} else {
1149 			microtime(&tv);
1150 		}
1151 		*mp = sbcreatecontrol((caddr_t)&tv, sizeof(tv), SCM_TIMESTAMP,
1152 		    SOL_SOCKET, M_NOWAIT);
1153 		if (*mp != NULL) {
1154 			mp = &(*mp)->m_next;
1155 			stamped = true;
1156 		}
1157 	} else if (CHECK_SO_CT(inp->inp_socket, SO_TS_REALTIME)) {
1158 		struct bintime boottimebin;
1159 		struct timespec ts, ts1;
1160 
1161 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1162 		    M_TSTMP)) {
1163 			mbuf_tstmp2timespec(m, &ts);
1164 			getboottimebin(&boottimebin);
1165 			bintime2timespec(&boottimebin, &ts1);
1166 			timespecadd(&ts, &ts1, &ts);
1167 		} else {
1168 			nanotime(&ts);
1169 		}
1170 		*mp = sbcreatecontrol(&ts, sizeof(ts), SCM_REALTIME,
1171 		    SOL_SOCKET, M_NOWAIT);
1172 		if (*mp != NULL) {
1173 			mp = &(*mp)->m_next;
1174 			stamped = true;
1175 		}
1176 	} else if (CHECK_SO_CT(inp->inp_socket, SO_TS_MONOTONIC)) {
1177 		struct timespec ts;
1178 
1179 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1180 		    M_TSTMP))
1181 			mbuf_tstmp2timespec(m, &ts);
1182 		else
1183 			nanouptime(&ts);
1184 		*mp = sbcreatecontrol(&ts, sizeof(ts), SCM_MONOTONIC,
1185 		    SOL_SOCKET, M_NOWAIT);
1186 		if (*mp != NULL) {
1187 			mp = &(*mp)->m_next;
1188 			stamped = true;
1189 		}
1190 	}
1191 	if (stamped && (m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1192 	    M_TSTMP)) {
1193 		struct sock_timestamp_info sti;
1194 
1195 		bzero(&sti, sizeof(sti));
1196 		sti.st_info_flags = ST_INFO_HW;
1197 		if ((m->m_flags & M_TSTMP_HPREC) != 0)
1198 			sti.st_info_flags |= ST_INFO_HW_HPREC;
1199 		*mp = sbcreatecontrol(&sti, sizeof(sti), SCM_TIME_INFO,
1200 		    SOL_SOCKET, M_NOWAIT);
1201 		if (*mp != NULL)
1202 			mp = &(*mp)->m_next;
1203 	}
1204 	if (inp->inp_flags & INP_RECVDSTADDR) {
1205 		*mp = sbcreatecontrol(&ip->ip_dst, sizeof(struct in_addr),
1206 		    IP_RECVDSTADDR, IPPROTO_IP, M_NOWAIT);
1207 		if (*mp)
1208 			mp = &(*mp)->m_next;
1209 	}
1210 	if (inp->inp_flags & INP_RECVTTL) {
1211 		*mp = sbcreatecontrol(&ip->ip_ttl, sizeof(u_char), IP_RECVTTL,
1212 		    IPPROTO_IP, M_NOWAIT);
1213 		if (*mp)
1214 			mp = &(*mp)->m_next;
1215 	}
1216 #ifdef notyet
1217 	/* XXX
1218 	 * Moving these out of udp_input() made them even more broken
1219 	 * than they already were.
1220 	 */
1221 	/* options were tossed already */
1222 	if (inp->inp_flags & INP_RECVOPTS) {
1223 		*mp = sbcreatecontrol(opts_deleted_above,
1224 		    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP, M_NOWAIT);
1225 		if (*mp)
1226 			mp = &(*mp)->m_next;
1227 	}
1228 	/* ip_srcroute doesn't do what we want here, need to fix */
1229 	if (inp->inp_flags & INP_RECVRETOPTS) {
1230 		*mp = sbcreatecontrol(ip_srcroute(m), sizeof(struct in_addr),
1231 		    IP_RECVRETOPTS, IPPROTO_IP, M_NOWAIT);
1232 		if (*mp)
1233 			mp = &(*mp)->m_next;
1234 	}
1235 #endif
1236 	if (inp->inp_flags & INP_RECVIF) {
1237 		struct ifnet *ifp;
1238 		struct sdlbuf {
1239 			struct sockaddr_dl sdl;
1240 			u_char	pad[32];
1241 		} sdlbuf;
1242 		struct sockaddr_dl *sdp;
1243 		struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
1244 
1245 		if ((ifp = m->m_pkthdr.rcvif)) {
1246 			sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
1247 			/*
1248 			 * Change our mind and don't try copy.
1249 			 */
1250 			if (sdp->sdl_family != AF_LINK ||
1251 			    sdp->sdl_len > sizeof(sdlbuf)) {
1252 				goto makedummy;
1253 			}
1254 			bcopy(sdp, sdl2, sdp->sdl_len);
1255 		} else {
1256 makedummy:
1257 			sdl2->sdl_len =
1258 			    offsetof(struct sockaddr_dl, sdl_data[0]);
1259 			sdl2->sdl_family = AF_LINK;
1260 			sdl2->sdl_index = 0;
1261 			sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
1262 		}
1263 		*mp = sbcreatecontrol(sdl2, sdl2->sdl_len, IP_RECVIF,
1264 		    IPPROTO_IP, M_NOWAIT);
1265 		if (*mp)
1266 			mp = &(*mp)->m_next;
1267 	}
1268 	if (inp->inp_flags & INP_RECVTOS) {
1269 		*mp = sbcreatecontrol(&ip->ip_tos, sizeof(u_char), IP_RECVTOS,
1270 		    IPPROTO_IP, M_NOWAIT);
1271 		if (*mp)
1272 			mp = &(*mp)->m_next;
1273 	}
1274 
1275 	if (inp->inp_flags2 & INP_RECVFLOWID) {
1276 		uint32_t flowid, flow_type;
1277 
1278 		flowid = m->m_pkthdr.flowid;
1279 		flow_type = M_HASHTYPE_GET(m);
1280 
1281 		/*
1282 		 * XXX should handle the failure of one or the
1283 		 * other - don't populate both?
1284 		 */
1285 		*mp = sbcreatecontrol(&flowid, sizeof(uint32_t), IP_FLOWID,
1286 		    IPPROTO_IP, M_NOWAIT);
1287 		if (*mp)
1288 			mp = &(*mp)->m_next;
1289 		*mp = sbcreatecontrol(&flow_type, sizeof(uint32_t),
1290 		    IP_FLOWTYPE, IPPROTO_IP, M_NOWAIT);
1291 		if (*mp)
1292 			mp = &(*mp)->m_next;
1293 	}
1294 
1295 #ifdef	RSS
1296 	if (inp->inp_flags2 & INP_RECVRSSBUCKETID) {
1297 		uint32_t flowid, flow_type;
1298 		uint32_t rss_bucketid;
1299 
1300 		flowid = m->m_pkthdr.flowid;
1301 		flow_type = M_HASHTYPE_GET(m);
1302 
1303 		if (rss_hash2bucket(flowid, flow_type, &rss_bucketid) == 0) {
1304 			*mp = sbcreatecontrol(&rss_bucketid, sizeof(uint32_t),
1305 			    IP_RSSBUCKETID, IPPROTO_IP, M_NOWAIT);
1306 			if (*mp)
1307 				mp = &(*mp)->m_next;
1308 		}
1309 	}
1310 #endif
1311 }
1312 
1313 /*
1314  * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
1315  * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
1316  * locking.  This code remains in ip_input.c as ip_mroute.c is optionally
1317  * compiled.
1318  */
1319 VNET_DEFINE_STATIC(int, ip_rsvp_on);
1320 VNET_DEFINE(struct socket *, ip_rsvpd);
1321 
1322 #define	V_ip_rsvp_on		VNET(ip_rsvp_on)
1323 
1324 int
1325 ip_rsvp_init(struct socket *so)
1326 {
1327 
1328 	if (V_ip_rsvpd != NULL)
1329 		return EADDRINUSE;
1330 
1331 	V_ip_rsvpd = so;
1332 	/*
1333 	 * This may seem silly, but we need to be sure we don't over-increment
1334 	 * the RSVP counter, in case something slips up.
1335 	 */
1336 	if (!V_ip_rsvp_on) {
1337 		V_ip_rsvp_on = 1;
1338 		V_rsvp_on++;
1339 	}
1340 
1341 	return 0;
1342 }
1343 
1344 int
1345 ip_rsvp_done(void)
1346 {
1347 
1348 	V_ip_rsvpd = NULL;
1349 	/*
1350 	 * This may seem silly, but we need to be sure we don't over-decrement
1351 	 * the RSVP counter, in case something slips up.
1352 	 */
1353 	if (V_ip_rsvp_on) {
1354 		V_ip_rsvp_on = 0;
1355 		V_rsvp_on--;
1356 	}
1357 	return 0;
1358 }
1359 
1360 int
1361 rsvp_input(struct mbuf **mp, int *offp, int proto)
1362 {
1363 	struct mbuf *m;
1364 
1365 	m = *mp;
1366 	*mp = NULL;
1367 
1368 	if (rsvp_input_p) { /* call the real one if loaded */
1369 		*mp = m;
1370 		rsvp_input_p(mp, offp, proto);
1371 		return (IPPROTO_DONE);
1372 	}
1373 
1374 	/* Can still get packets with rsvp_on = 0 if there is a local member
1375 	 * of the group to which the RSVP packet is addressed.  But in this
1376 	 * case we want to throw the packet away.
1377 	 */
1378 
1379 	if (!V_rsvp_on) {
1380 		m_freem(m);
1381 		return (IPPROTO_DONE);
1382 	}
1383 
1384 	if (V_ip_rsvpd != NULL) {
1385 		*mp = m;
1386 		rip_input(mp, offp, proto);
1387 		return (IPPROTO_DONE);
1388 	}
1389 	/* Drop the packet */
1390 	m_freem(m);
1391 	return (IPPROTO_DONE);
1392 }
1393