xref: /freebsd/sys/netinet/ip_input.c (revision 576ee62dd2e5e0454a5316eb9207f4ebaa543171)
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 
32 #include "opt_bootp.h"
33 #include "opt_inet.h"
34 #include "opt_ipstealth.h"
35 #include "opt_ipsec.h"
36 #include "opt_route.h"
37 #include "opt_rss.h"
38 #include "opt_sctp.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/hhook.h>
43 #include <sys/mbuf.h>
44 #include <sys/malloc.h>
45 #include <sys/domain.h>
46 #include <sys/protosw.h>
47 #include <sys/socket.h>
48 #include <sys/time.h>
49 #include <sys/kernel.h>
50 #include <sys/lock.h>
51 #include <sys/rmlock.h>
52 #include <sys/rwlock.h>
53 #include <sys/sdt.h>
54 #include <sys/syslog.h>
55 #include <sys/sysctl.h>
56 
57 #include <net/if.h>
58 #include <net/if_types.h>
59 #include <net/if_var.h>
60 #include <net/if_dl.h>
61 #include <net/if_private.h>
62 #include <net/pfil.h>
63 #include <net/route.h>
64 #include <net/route/nhop.h>
65 #include <net/netisr.h>
66 #include <net/rss_config.h>
67 #include <net/vnet.h>
68 
69 #include <netinet/in.h>
70 #include <netinet/in_kdtrace.h>
71 #include <netinet/in_systm.h>
72 #include <netinet/in_var.h>
73 #include <netinet/ip.h>
74 #include <netinet/in_fib.h>
75 #include <netinet/in_pcb.h>
76 #include <netinet/ip_var.h>
77 #include <netinet/ip_encap.h>
78 #include <netinet/ip_fw.h>
79 #include <netinet/ip_icmp.h>
80 #include <netinet/igmp_var.h>
81 #include <netinet/ip_options.h>
82 #include <machine/in_cksum.h>
83 #include <netinet/ip_carp.h>
84 #include <netinet/in_rss.h>
85 #ifdef SCTP
86 #include <netinet/sctp_var.h>
87 #endif
88 
89 #include <netipsec/ipsec_support.h>
90 
91 #include <sys/socketvar.h>
92 
93 #include <security/mac/mac_framework.h>
94 
95 #ifdef CTASSERT
96 CTASSERT(sizeof(struct ip) == 20);
97 #endif
98 
99 /* IP reassembly functions are defined in ip_reass.c. */
100 extern void ipreass_init(void);
101 extern void ipreass_vnet_init(void);
102 #ifdef VIMAGE
103 extern void ipreass_destroy(void);
104 #endif
105 
106 VNET_DEFINE(int, rsvp_on);
107 
108 VNET_DEFINE(int, ipforwarding);
109 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_VNET | CTLFLAG_RW,
110     &VNET_NAME(ipforwarding), 0,
111     "Enable IP forwarding between interfaces");
112 
113 /*
114  * Respond with an ICMP host redirect when we forward a packet out of
115  * the same interface on which it was received.  See RFC 792.
116  */
117 VNET_DEFINE(int, ipsendredirects) = 1;
118 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_VNET | CTLFLAG_RW,
119     &VNET_NAME(ipsendredirects), 0,
120     "Enable sending IP redirects");
121 
122 VNET_DEFINE_STATIC(bool, ip_strong_es) = false;
123 #define	V_ip_strong_es	VNET(ip_strong_es)
124 SYSCTL_BOOL(_net_inet_ip, OID_AUTO, rfc1122_strong_es,
125     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_strong_es), false,
126     "Packet's IP destination address must match address on arrival interface");
127 
128 VNET_DEFINE_STATIC(bool, ip_sav) = true;
129 #define	V_ip_sav	VNET(ip_sav)
130 SYSCTL_BOOL(_net_inet_ip, OID_AUTO, source_address_validation,
131     CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_sav), true,
132     "Drop incoming packets with source address that is a local address");
133 
134 /* Packet filter hooks */
135 VNET_DEFINE(pfil_head_t, inet_pfil_head);
136 VNET_DEFINE(pfil_head_t, inet_local_pfil_head);
137 
138 static struct netisr_handler ip_nh = {
139 	.nh_name = "ip",
140 	.nh_handler = ip_input,
141 	.nh_proto = NETISR_IP,
142 #ifdef	RSS
143 	.nh_m2cpuid = rss_soft_m2cpuid_v4,
144 	.nh_policy = NETISR_POLICY_CPU,
145 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
146 #else
147 	.nh_policy = NETISR_POLICY_FLOW,
148 #endif
149 };
150 
151 #ifdef	RSS
152 /*
153  * Directly dispatched frames are currently assumed
154  * to have a flowid already calculated.
155  *
156  * It should likely have something that assert it
157  * actually has valid flow details.
158  */
159 static struct netisr_handler ip_direct_nh = {
160 	.nh_name = "ip_direct",
161 	.nh_handler = ip_direct_input,
162 	.nh_proto = NETISR_IP_DIRECT,
163 	.nh_m2cpuid = rss_soft_m2cpuid_v4,
164 	.nh_policy = NETISR_POLICY_CPU,
165 	.nh_dispatch = NETISR_DISPATCH_HYBRID,
166 };
167 #endif
168 
169 ipproto_input_t		*ip_protox[IPPROTO_MAX] = {
170 			    [0 ... IPPROTO_MAX - 1] = rip_input };
171 ipproto_ctlinput_t	*ip_ctlprotox[IPPROTO_MAX] = {
172 			    [0 ... IPPROTO_MAX - 1] = rip_ctlinput };
173 
174 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead);  /* first inet address */
175 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table  */
176 VNET_DEFINE(u_long, in_ifaddrhmask);		/* mask for hash table */
177 
178 /* Make sure it is safe to use hashinit(9) on CK_LIST. */
179 CTASSERT(sizeof(struct in_ifaddrhashhead) == sizeof(LIST_HEAD(, in_addr)));
180 
181 #ifdef IPCTL_DEFMTU
182 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
183     &ip_mtu, 0, "Default MTU");
184 #endif
185 
186 #ifdef IPSTEALTH
187 VNET_DEFINE(int, ipstealth);
188 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_VNET | CTLFLAG_RW,
189     &VNET_NAME(ipstealth), 0,
190     "IP stealth mode, no TTL decrementation on forwarding");
191 #endif
192 
193 /*
194  * IP statistics are stored in the "array" of counter(9)s.
195  */
196 VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat);
197 VNET_PCPUSTAT_SYSINIT(ipstat);
198 SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat,
199     "IP statistics (struct ipstat, netinet/ip_var.h)");
200 
201 #ifdef VIMAGE
202 VNET_PCPUSTAT_SYSUNINIT(ipstat);
203 #endif /* VIMAGE */
204 
205 /*
206  * Kernel module interface for updating ipstat.  The argument is an index
207  * into ipstat treated as an array.
208  */
209 void
210 kmod_ipstat_inc(int statnum)
211 {
212 
213 	counter_u64_add(VNET(ipstat)[statnum], 1);
214 }
215 
216 void
217 kmod_ipstat_dec(int statnum)
218 {
219 
220 	counter_u64_add(VNET(ipstat)[statnum], -1);
221 }
222 
223 static int
224 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
225 {
226 	int error, qlimit;
227 
228 	netisr_getqlimit(&ip_nh, &qlimit);
229 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
230 	if (error || !req->newptr)
231 		return (error);
232 	if (qlimit < 1)
233 		return (EINVAL);
234 	return (netisr_setqlimit(&ip_nh, qlimit));
235 }
236 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
237     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
238     sysctl_netinet_intr_queue_maxlen, "I",
239     "Maximum size of the IP input queue");
240 
241 static int
242 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
243 {
244 	u_int64_t qdrops_long;
245 	int error, qdrops;
246 
247 	netisr_getqdrops(&ip_nh, &qdrops_long);
248 	qdrops = qdrops_long;
249 	error = sysctl_handle_int(oidp, &qdrops, 0, req);
250 	if (error || !req->newptr)
251 		return (error);
252 	if (qdrops != 0)
253 		return (EINVAL);
254 	netisr_clearqdrops(&ip_nh);
255 	return (0);
256 }
257 
258 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
259     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
260     0, 0, sysctl_netinet_intr_queue_drops, "I",
261     "Number of packets dropped from the IP input queue");
262 
263 #ifdef	RSS
264 static int
265 sysctl_netinet_intr_direct_queue_maxlen(SYSCTL_HANDLER_ARGS)
266 {
267 	int error, qlimit;
268 
269 	netisr_getqlimit(&ip_direct_nh, &qlimit);
270 	error = sysctl_handle_int(oidp, &qlimit, 0, req);
271 	if (error || !req->newptr)
272 		return (error);
273 	if (qlimit < 1)
274 		return (EINVAL);
275 	return (netisr_setqlimit(&ip_direct_nh, qlimit));
276 }
277 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRDQMAXLEN, intr_direct_queue_maxlen,
278     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
279     0, 0, sysctl_netinet_intr_direct_queue_maxlen,
280     "I", "Maximum size of the IP direct input queue");
281 
282 static int
283 sysctl_netinet_intr_direct_queue_drops(SYSCTL_HANDLER_ARGS)
284 {
285 	u_int64_t qdrops_long;
286 	int error, qdrops;
287 
288 	netisr_getqdrops(&ip_direct_nh, &qdrops_long);
289 	qdrops = qdrops_long;
290 	error = sysctl_handle_int(oidp, &qdrops, 0, req);
291 	if (error || !req->newptr)
292 		return (error);
293 	if (qdrops != 0)
294 		return (EINVAL);
295 	netisr_clearqdrops(&ip_direct_nh);
296 	return (0);
297 }
298 
299 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRDQDROPS, intr_direct_queue_drops,
300     CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
301     sysctl_netinet_intr_direct_queue_drops, "I",
302     "Number of packets dropped from the IP direct input queue");
303 #endif	/* RSS */
304 
305 /*
306  * IP initialization: fill in IP protocol switch table.
307  * All protocols not implemented in kernel go to raw IP protocol handler.
308  */
309 static void
310 ip_vnet_init(void *arg __unused)
311 {
312 	struct pfil_head_args args;
313 
314 	CK_STAILQ_INIT(&V_in_ifaddrhead);
315 	V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
316 
317 	/* Initialize IP reassembly queue. */
318 	ipreass_vnet_init();
319 
320 	/* Initialize packet filter hooks. */
321 	args.pa_version = PFIL_VERSION;
322 	args.pa_flags = PFIL_IN | PFIL_OUT;
323 	args.pa_type = PFIL_TYPE_IP4;
324 	args.pa_headname = PFIL_INET_NAME;
325 	V_inet_pfil_head = pfil_head_register(&args);
326 
327 	args.pa_flags = PFIL_OUT;
328 	args.pa_headname = PFIL_INET_LOCAL_NAME;
329 	V_inet_local_pfil_head = pfil_head_register(&args);
330 
331 	if (hhook_head_register(HHOOK_TYPE_IPSEC_IN, AF_INET,
332 	    &V_ipsec_hhh_in[HHOOK_IPSEC_INET],
333 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
334 		printf("%s: WARNING: unable to register input helper hook\n",
335 		    __func__);
336 	if (hhook_head_register(HHOOK_TYPE_IPSEC_OUT, AF_INET,
337 	    &V_ipsec_hhh_out[HHOOK_IPSEC_INET],
338 	    HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
339 		printf("%s: WARNING: unable to register output helper hook\n",
340 		    __func__);
341 
342 #ifdef VIMAGE
343 	netisr_register_vnet(&ip_nh);
344 #ifdef	RSS
345 	netisr_register_vnet(&ip_direct_nh);
346 #endif
347 #endif
348 }
349 VNET_SYSINIT(ip_vnet_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
350     ip_vnet_init, NULL);
351 
352 static void
353 ip_init(const void *unused __unused)
354 {
355 	struct ifnet *ifp;
356 
357 	ipreass_init();
358 
359 	/*
360 	 * Register statically compiled protocols, that are unlikely to
361 	 * ever become dynamic.
362 	 */
363 	IPPROTO_REGISTER(IPPROTO_ICMP, icmp_input, NULL);
364 	IPPROTO_REGISTER(IPPROTO_IGMP, igmp_input, NULL);
365 	IPPROTO_REGISTER(IPPROTO_RSVP, rsvp_input, NULL);
366 	IPPROTO_REGISTER(IPPROTO_IPV4, encap4_input, NULL);
367 	IPPROTO_REGISTER(IPPROTO_MOBILE, encap4_input, NULL);
368 	IPPROTO_REGISTER(IPPROTO_ETHERIP, encap4_input, NULL);
369 	IPPROTO_REGISTER(IPPROTO_GRE, encap4_input, NULL);
370 	IPPROTO_REGISTER(IPPROTO_IPV6, encap4_input, NULL);
371 	IPPROTO_REGISTER(IPPROTO_PIM, encap4_input, NULL);
372 #ifdef SCTP	/* XXX: has a loadable & static version */
373 	IPPROTO_REGISTER(IPPROTO_SCTP, sctp_input, sctp_ctlinput);
374 #endif
375 
376 	netisr_register(&ip_nh);
377 #ifdef	RSS
378 	netisr_register(&ip_direct_nh);
379 #endif
380 	/*
381 	 * XXXGL: we use SYSINIT() here, but go over V_ifnet.  It was the same
382 	 * way before dom_ifattach removal.  This worked because when any
383 	 * non-default vnet is created, there are no interfaces inside.
384 	 * Eventually this needs to be fixed.
385 	 */
386 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link)
387 		in_ifattach(NULL, ifp);
388 }
389 SYSINIT(ip_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip_init, NULL);
390 
391 #ifdef VIMAGE
392 static void
393 ip_destroy(void *unused __unused)
394 {
395 	int error;
396 
397 #ifdef	RSS
398 	netisr_unregister_vnet(&ip_direct_nh);
399 #endif
400 	netisr_unregister_vnet(&ip_nh);
401 
402 	pfil_head_unregister(V_inet_pfil_head);
403 	error = hhook_head_deregister(V_ipsec_hhh_in[HHOOK_IPSEC_INET]);
404 	if (error != 0) {
405 		printf("%s: WARNING: unable to deregister input helper hook "
406 		    "type HHOOK_TYPE_IPSEC_IN, id HHOOK_IPSEC_INET: "
407 		    "error %d returned\n", __func__, error);
408 	}
409 	error = hhook_head_deregister(V_ipsec_hhh_out[HHOOK_IPSEC_INET]);
410 	if (error != 0) {
411 		printf("%s: WARNING: unable to deregister output helper hook "
412 		    "type HHOOK_TYPE_IPSEC_OUT, id HHOOK_IPSEC_INET: "
413 		    "error %d returned\n", __func__, error);
414 	}
415 
416 	/* Remove the IPv4 addresses from all interfaces. */
417 	in_ifscrub_all();
418 
419 	/* Make sure the IPv4 routes are gone as well. */
420 	rib_flush_routes_family(AF_INET);
421 
422 	/* Destroy IP reassembly queue. */
423 	ipreass_destroy();
424 
425 	/* Cleanup in_ifaddr hash table; should be empty. */
426 	hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
427 }
428 
429 VNET_SYSUNINIT(ip, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip_destroy, NULL);
430 #endif
431 
432 #ifdef	RSS
433 /*
434  * IP direct input routine.
435  *
436  * This is called when reinjecting completed fragments where
437  * all of the previous checking and book-keeping has been done.
438  */
439 void
440 ip_direct_input(struct mbuf *m)
441 {
442 	struct ip *ip;
443 	int hlen;
444 
445 	ip = mtod(m, struct ip *);
446 	hlen = ip->ip_hl << 2;
447 
448 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
449 	if (IPSEC_ENABLED(ipv4)) {
450 		if (IPSEC_INPUT(ipv4, m, hlen, ip->ip_p) != 0)
451 			return;
452 	}
453 #endif /* IPSEC */
454 	IPSTAT_INC(ips_delivered);
455 	ip_protox[ip->ip_p](&m, &hlen, ip->ip_p);
456 }
457 #endif
458 
459 /*
460  * Ip input routine.  Checksum and byte swap header.  If fragmented
461  * try to reassemble.  Process options.  Pass to next level.
462  */
463 void
464 ip_input(struct mbuf *m)
465 {
466 	struct ip *ip = NULL;
467 	struct in_ifaddr *ia = NULL;
468 	struct ifaddr *ifa;
469 	struct ifnet *ifp;
470 	int hlen = 0;
471 	uint16_t sum, ip_len;
472 	int dchg = 0;				/* dest changed after fw */
473 	struct in_addr odst;			/* original dst address */
474 	bool strong_es;
475 
476 	M_ASSERTPKTHDR(m);
477 	NET_EPOCH_ASSERT();
478 
479 	if (m->m_flags & M_FASTFWD_OURS) {
480 		m->m_flags &= ~M_FASTFWD_OURS;
481 		/* Set up some basics that will be used later. */
482 		ip = mtod(m, struct ip *);
483 		hlen = ip->ip_hl << 2;
484 		ip_len = ntohs(ip->ip_len);
485 		goto ours;
486 	}
487 
488 	IPSTAT_INC(ips_total);
489 
490 	if (__predict_false(m->m_pkthdr.len < sizeof(struct ip)))
491 		goto tooshort;
492 
493 	if (m->m_len < sizeof(struct ip)) {
494 		m = m_pullup(m, sizeof(struct ip));
495 		if (__predict_false(m == NULL)) {
496 			IPSTAT_INC(ips_toosmall);
497 			return;
498 		}
499 	}
500 	ip = mtod(m, struct ip *);
501 
502 	if (__predict_false(ip->ip_v != IPVERSION)) {
503 		IPSTAT_INC(ips_badvers);
504 		goto bad;
505 	}
506 
507 	hlen = ip->ip_hl << 2;
508 	if (__predict_false(hlen < sizeof(struct ip))) {	/* minimum header length */
509 		IPSTAT_INC(ips_badhlen);
510 		goto bad;
511 	}
512 	if (hlen > m->m_len) {
513 		m = m_pullup(m, hlen);
514 		if (__predict_false(m == NULL)) {
515 			IPSTAT_INC(ips_badhlen);
516 			return;
517 		}
518 		ip = mtod(m, struct ip *);
519 	}
520 
521 	IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL);
522 
523 	/* IN_LOOPBACK must not appear on the wire - RFC1122 */
524 	ifp = m->m_pkthdr.rcvif;
525 	if (IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
526 	    IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) {
527 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
528 			IPSTAT_INC(ips_badaddr);
529 			goto bad;
530 		}
531 	}
532 
533 	if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
534 		sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
535 	} else if (m->m_pkthdr.csum_flags & CSUM_IP) {
536 		/*
537 		 * Packet from local host that offloaded checksum computation.
538 		 * Checksum not required since the packet wasn't on the wire.
539 		 */
540 		sum = 0;
541 	} else {
542 		if (hlen == sizeof(struct ip)) {
543 			sum = in_cksum_hdr(ip);
544 		} else {
545 			sum = in_cksum(m, hlen);
546 		}
547 	}
548 	if (__predict_false(sum)) {
549 		IPSTAT_INC(ips_badsum);
550 		goto bad;
551 	}
552 
553 	ip_len = ntohs(ip->ip_len);
554 	if (__predict_false(ip_len < hlen)) {
555 		IPSTAT_INC(ips_badlen);
556 		goto bad;
557 	}
558 
559 	/*
560 	 * Check that the amount of data in the buffers
561 	 * is as at least much as the IP header would have us expect.
562 	 * Trim mbufs if longer than we expect.
563 	 * Drop packet if shorter than we expect.
564 	 */
565 	if (__predict_false(m->m_pkthdr.len < ip_len)) {
566 tooshort:
567 		IPSTAT_INC(ips_tooshort);
568 		goto bad;
569 	}
570 	if (m->m_pkthdr.len > ip_len) {
571 		if (m->m_len == m->m_pkthdr.len) {
572 			m->m_len = ip_len;
573 			m->m_pkthdr.len = ip_len;
574 		} else
575 			m_adj(m, ip_len - m->m_pkthdr.len);
576 	}
577 
578 	/*
579 	 * Try to forward the packet, but if we fail continue.
580 	 * ip_tryforward() may generate redirects these days.
581 	 * XXX the logic below falling through to normal processing
582 	 * if redirects are required should be revisited as well.
583 	 * ip_tryforward() does inbound and outbound packet firewall
584 	 * processing. If firewall has decided that destination becomes
585 	 * our local address, it sets M_FASTFWD_OURS flag. In this
586 	 * case skip another inbound firewall processing and update
587 	 * ip pointer.
588 	 */
589 	if (V_ipforwarding != 0
590 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
591 	    && (!IPSEC_ENABLED(ipv4) ||
592 	    IPSEC_CAPS(ipv4, m, IPSEC_CAP_OPERABLE) == 0)
593 #endif
594 	    ) {
595 		/*
596 		 * ip_dooptions() was run so we can ignore the source route (or
597 		 * any IP options case) case for redirects in ip_tryforward().
598 		 */
599 		if ((m = ip_tryforward(m)) == NULL)
600 			return;
601 		if (m->m_flags & M_FASTFWD_OURS) {
602 			m->m_flags &= ~M_FASTFWD_OURS;
603 			ip = mtod(m, struct ip *);
604 			goto ours;
605 		}
606 	}
607 
608 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
609 	/*
610 	 * Bypass packet filtering for packets previously handled by IPsec.
611 	 */
612 	if (IPSEC_ENABLED(ipv4) &&
613 	    IPSEC_CAPS(ipv4, m, IPSEC_CAP_BYPASS_FILTER) != 0)
614 			goto passin;
615 #endif
616 
617 	/*
618 	 * Run through list of hooks for input packets.
619 	 *
620 	 * NB: Beware of the destination address changing (e.g.
621 	 *     by NAT rewriting).  When this happens, tell
622 	 *     ip_forward to do the right thing.
623 	 */
624 
625 	/* Jump over all PFIL processing if hooks are not active. */
626 	if (!PFIL_HOOKED_IN(V_inet_pfil_head))
627 		goto passin;
628 
629 	odst = ip->ip_dst;
630 	if (pfil_mbuf_in(V_inet_pfil_head, &m, ifp, NULL) !=
631 	    PFIL_PASS)
632 		return;
633 
634 	ip = mtod(m, struct ip *);
635 	dchg = (odst.s_addr != ip->ip_dst.s_addr);
636 
637 	if (m->m_flags & M_FASTFWD_OURS) {
638 		m->m_flags &= ~M_FASTFWD_OURS;
639 		goto ours;
640 	}
641 	if (m->m_flags & M_IP_NEXTHOP) {
642 		if (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) {
643 			/*
644 			 * Directly ship the packet on.  This allows
645 			 * forwarding packets originally destined to us
646 			 * to some other directly connected host.
647 			 */
648 			ip_forward(m, 1);
649 			return;
650 		}
651 	}
652 passin:
653 	/*
654 	 * The unspecified address can appear only as a src address - RFC1122.
655 	 *
656 	 * The check is deferred to here to give firewalls a chance to block
657 	 * (and log) such packets.  ip_tryforward() will not process such
658 	 * packets.
659 	 */
660 	if (__predict_false(ntohl(ip->ip_dst.s_addr) == INADDR_ANY)) {
661 		IPSTAT_INC(ips_badaddr);
662 		goto bad;
663 	}
664 
665 	/*
666 	 * Process options and, if not destined for us,
667 	 * ship it on.  ip_dooptions returns 1 when an
668 	 * error was detected (causing an icmp message
669 	 * to be sent and the original packet to be freed).
670 	 */
671 	if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
672 		return;
673 
674         /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
675          * matter if it is destined to another node, or whether it is
676          * a multicast one, RSVP wants it! and prevents it from being forwarded
677          * anywhere else. Also checks if the rsvp daemon is running before
678 	 * grabbing the packet.
679          */
680 	if (ip->ip_p == IPPROTO_RSVP && V_rsvp_on)
681 		goto ours;
682 
683 	/*
684 	 * Check our list of addresses, to see if the packet is for us.
685 	 * If we don't have any addresses, assume any unicast packet
686 	 * we receive might be for us (and let the upper layers deal
687 	 * with it).
688 	 */
689 	if (CK_STAILQ_EMPTY(&V_in_ifaddrhead) &&
690 	    (m->m_flags & (M_MCAST|M_BCAST)) == 0)
691 		goto ours;
692 
693 	/*
694 	 * Enable a consistency check between the destination address
695 	 * and the arrival interface for a unicast packet (the RFC 1122
696 	 * strong ES model) with a list of additional predicates:
697 	 * - if IP forwarding is disabled
698 	 * - the packet is not locally generated
699 	 * - the packet is not subject to 'ipfw fwd'
700 	 * - Interface is not running CARP. If the packet got here, we already
701 	 *   checked it with carp_iamatch() and carp_forus().
702 	 */
703 	strong_es = V_ip_strong_es && (V_ipforwarding == 0) &&
704 	    ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
705 	    ifp->if_carp == NULL && (dchg == 0);
706 
707 	/*
708 	 * Check for exact addresses in the hash bucket.
709 	 */
710 	CK_LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
711 		if (IA_SIN(ia)->sin_addr.s_addr != ip->ip_dst.s_addr)
712 			continue;
713 
714 		/*
715 		 * net.inet.ip.rfc1122_strong_es: the address matches, verify
716 		 * that the packet arrived via the correct interface.
717 		 */
718 		if (__predict_false(strong_es && ia->ia_ifp != ifp)) {
719 			IPSTAT_INC(ips_badaddr);
720 			goto bad;
721 		}
722 
723 		/*
724 		 * net.inet.ip.source_address_validation: drop incoming
725 		 * packets that pretend to be ours.
726 		 */
727 		if (V_ip_sav && !(ifp->if_flags & IFF_LOOPBACK) &&
728 		    __predict_false(in_localip_fib(ip->ip_src, ifp->if_fib))) {
729 			IPSTAT_INC(ips_badaddr);
730 			goto bad;
731 		}
732 
733 		counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
734 		counter_u64_add(ia->ia_ifa.ifa_ibytes, m->m_pkthdr.len);
735 		goto ours;
736 	}
737 
738 	/*
739 	 * Check for broadcast addresses.
740 	 *
741 	 * Only accept broadcast packets that arrive via the matching
742 	 * interface.  Reception of forwarded directed broadcasts would
743 	 * be handled via ip_forward() and ether_output() with the loopback
744 	 * into the stack for SIMPLEX interfaces handled by ether_output().
745 	 */
746 	if (ifp->if_flags & IFF_BROADCAST) {
747 		CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
748 			if (ifa->ifa_addr->sa_family != AF_INET)
749 				continue;
750 			ia = ifatoia(ifa);
751 			if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
752 			    ip->ip_dst.s_addr) {
753 				counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
754 				counter_u64_add(ia->ia_ifa.ifa_ibytes,
755 				    m->m_pkthdr.len);
756 				goto ours;
757 			}
758 #ifdef BOOTP_COMPAT
759 			if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
760 				counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
761 				counter_u64_add(ia->ia_ifa.ifa_ibytes,
762 				    m->m_pkthdr.len);
763 				goto ours;
764 			}
765 #endif
766 		}
767 		ia = NULL;
768 	}
769 	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
770 		/*
771 		 * RFC 3927 2.7: Do not forward multicast packets from
772 		 * IN_LINKLOCAL.
773 		 */
774 		if (V_ip_mrouter && !IN_LINKLOCAL(ntohl(ip->ip_src.s_addr))) {
775 			/*
776 			 * If we are acting as a multicast router, all
777 			 * incoming multicast packets are passed to the
778 			 * kernel-level multicast forwarding function.
779 			 * The packet is returned (relatively) intact; if
780 			 * ip_mforward() returns a non-zero value, the packet
781 			 * must be discarded, else it may be accepted below.
782 			 */
783 			if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
784 				IPSTAT_INC(ips_cantforward);
785 				m_freem(m);
786 				return;
787 			}
788 
789 			/*
790 			 * The process-level routing daemon needs to receive
791 			 * all multicast IGMP packets, whether or not this
792 			 * host belongs to their destination groups.
793 			 */
794 			if (ip->ip_p == IPPROTO_IGMP) {
795 				goto ours;
796 			}
797 			IPSTAT_INC(ips_forward);
798 		}
799 		/*
800 		 * Assume the packet is for us, to avoid prematurely taking
801 		 * a lock on the in_multi hash. Protocols must perform
802 		 * their own filtering and update statistics accordingly.
803 		 */
804 		goto ours;
805 	}
806 	if (in_broadcast(ip->ip_dst))
807 		goto ours;
808 	/* RFC 3927 2.7: Do not forward packets to or from IN_LINKLOCAL. */
809 	if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) ||
810 	    IN_LINKLOCAL(ntohl(ip->ip_src.s_addr))) {
811 		IPSTAT_INC(ips_cantforward);
812 		m_freem(m);
813 		return;
814 	}
815 
816 	/*
817 	 * Not for us; forward if possible and desirable.
818 	 */
819 	if (V_ipforwarding == 0) {
820 		IPSTAT_INC(ips_cantforward);
821 		m_freem(m);
822 	} else {
823 		ip_forward(m, dchg);
824 	}
825 	return;
826 
827 ours:
828 #ifdef IPSTEALTH
829 	/*
830 	 * IPSTEALTH: Process non-routing options only
831 	 * if the packet is destined for us.
832 	 */
833 	if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1))
834 		return;
835 #endif /* IPSTEALTH */
836 
837 	/*
838 	 * We are going to ship the packet to the local protocol stack. Call the
839 	 * filter again for this 'output' action, allowing redirect-like rules
840 	 * to adjust the source address.
841 	 */
842 	if (PFIL_HOOKED_OUT(V_inet_local_pfil_head)) {
843 		if (pfil_mbuf_out(V_inet_local_pfil_head, &m, V_loif, NULL) !=
844 		    PFIL_PASS)
845 			return;
846 		ip = mtod(m, struct ip *);
847 	}
848 
849 	/*
850 	 * Attempt reassembly; if it succeeds, proceed.
851 	 * ip_reass() will return a different mbuf.
852 	 */
853 	if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
854 		/* XXXGL: shouldn't we save & set m_flags? */
855 		m = ip_reass(m);
856 		if (m == NULL)
857 			return;
858 		ip = mtod(m, struct ip *);
859 		/* Get the header length of the reassembled packet */
860 		hlen = ip->ip_hl << 2;
861 	}
862 
863 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
864 	if (IPSEC_ENABLED(ipv4)) {
865 		if (IPSEC_INPUT(ipv4, m, hlen, ip->ip_p) != 0)
866 			return;
867 	}
868 #endif /* IPSEC */
869 
870 	/*
871 	 * Switch out to protocol's input routine.
872 	 */
873 	IPSTAT_INC(ips_delivered);
874 
875 	ip_protox[ip->ip_p](&m, &hlen, ip->ip_p);
876 	return;
877 bad:
878 	m_freem(m);
879 }
880 
881 int
882 ipproto_register(uint8_t proto, ipproto_input_t input, ipproto_ctlinput_t ctl)
883 {
884 
885 	MPASS(proto > 0);
886 
887 	/*
888 	 * The protocol slot must not be occupied by another protocol
889 	 * already.  An index pointing to rip_input() is unused.
890 	 */
891 	if (ip_protox[proto] == rip_input) {
892 		ip_protox[proto] = input;
893 		ip_ctlprotox[proto] = ctl;
894 		return (0);
895 	} else
896 		return (EEXIST);
897 }
898 
899 int
900 ipproto_unregister(uint8_t proto)
901 {
902 
903 	MPASS(proto > 0);
904 
905 	if (ip_protox[proto] != rip_input) {
906 		ip_protox[proto] = rip_input;
907 		ip_ctlprotox[proto] = rip_ctlinput;
908 		return (0);
909 	} else
910 		return (ENOENT);
911 }
912 
913 /*
914  * Forward a packet.  If some error occurs return the sender
915  * an icmp packet.  Note we can't always generate a meaningful
916  * icmp message because icmp doesn't have a large enough repertoire
917  * of codes and types.
918  *
919  * If not forwarding, just drop the packet.  This could be confusing
920  * if ipforwarding was zero but some routing protocol was advancing
921  * us as a gateway to somewhere.  However, we must let the routing
922  * protocol deal with that.
923  *
924  * The srcrt parameter indicates whether the packet is being forwarded
925  * via a source route.
926  */
927 void
928 ip_forward(struct mbuf *m, int srcrt)
929 {
930 	struct ip *ip = mtod(m, struct ip *);
931 	struct in_ifaddr *ia;
932 	struct mbuf *mcopy;
933 	struct sockaddr_in *sin;
934 	struct in_addr dest;
935 	struct route ro;
936 	uint32_t flowid;
937 	int error, type = 0, code = 0, mtu = 0;
938 
939 	NET_EPOCH_ASSERT();
940 
941 	if (m->m_flags & (M_BCAST|M_MCAST) || !in_canforward(ip->ip_dst)) {
942 		IPSTAT_INC(ips_cantforward);
943 		m_freem(m);
944 		return;
945 	}
946 	if (
947 #ifdef IPSTEALTH
948 	    V_ipstealth == 0 &&
949 #endif
950 	    ip->ip_ttl <= IPTTLDEC) {
951 		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, 0);
952 		return;
953 	}
954 
955 	bzero(&ro, sizeof(ro));
956 	sin = (struct sockaddr_in *)&ro.ro_dst;
957 	sin->sin_family = AF_INET;
958 	sin->sin_len = sizeof(*sin);
959 	sin->sin_addr = ip->ip_dst;
960 	flowid = m->m_pkthdr.flowid;
961 	ro.ro_nh = fib4_lookup(M_GETFIB(m), ip->ip_dst, 0, NHR_REF, flowid);
962 	if (ro.ro_nh != NULL) {
963 		if (ro.ro_nh->nh_flags & (NHF_BLACKHOLE | NHF_BROADCAST)) {
964 			IPSTAT_INC(ips_cantforward);
965 			m_freem(m);
966 			NH_FREE(ro.ro_nh);
967 			return;
968 		}
969 		if (ro.ro_nh->nh_flags & NHF_REJECT) {
970 			IPSTAT_INC(ips_cantforward);
971 			NH_FREE(ro.ro_nh);
972 			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
973 			return;
974 		}
975 		ia = ifatoia(ro.ro_nh->nh_ifa);
976 	} else
977 		ia = NULL;
978 	/*
979 	 * Save the IP header and at most 8 bytes of the payload,
980 	 * in case we need to generate an ICMP message to the src.
981 	 *
982 	 * XXX this can be optimized a lot by saving the data in a local
983 	 * buffer on the stack (72 bytes at most), and only allocating the
984 	 * mbuf if really necessary. The vast majority of the packets
985 	 * are forwarded without having to send an ICMP back (either
986 	 * because unnecessary, or because rate limited), so we are
987 	 * really we are wasting a lot of work here.
988 	 *
989 	 * We don't use m_copym() because it might return a reference
990 	 * to a shared cluster. Both this function and ip_output()
991 	 * assume exclusive access to the IP header in `m', so any
992 	 * data in a cluster may change before we reach icmp_error().
993 	 */
994 	mcopy = m_gethdr(M_NOWAIT, m->m_type);
995 	if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) {
996 		/*
997 		 * It's probably ok if the pkthdr dup fails (because
998 		 * the deep copy of the tag chain failed), but for now
999 		 * be conservative and just discard the copy since
1000 		 * code below may some day want the tags.
1001 		 */
1002 		m_free(mcopy);
1003 		mcopy = NULL;
1004 	}
1005 	if (mcopy != NULL) {
1006 		mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy));
1007 		mcopy->m_pkthdr.len = mcopy->m_len;
1008 		m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1009 	}
1010 #ifdef IPSTEALTH
1011 	if (V_ipstealth == 0)
1012 #endif
1013 		ip->ip_ttl -= IPTTLDEC;
1014 #if defined(IPSEC) || defined(IPSEC_SUPPORT)
1015 	if (IPSEC_ENABLED(ipv4)) {
1016 		if ((error = IPSEC_FORWARD(ipv4, m)) != 0) {
1017 			/* mbuf consumed by IPsec */
1018 			RO_NHFREE(&ro);
1019 			m_freem(mcopy);
1020 			if (error != EINPROGRESS)
1021 				IPSTAT_INC(ips_cantforward);
1022 			return;
1023 		}
1024 		/* No IPsec processing required */
1025 	}
1026 #endif /* IPSEC */
1027 	/*
1028 	 * If forwarding packet using same interface that it came in on,
1029 	 * perhaps should send a redirect to sender to shortcut a hop.
1030 	 * Only send redirect if source is sending directly to us,
1031 	 * and if packet was not source routed (or has any options).
1032 	 * Also, don't send redirect if forwarding using a default route
1033 	 * or a route modified by a redirect.
1034 	 */
1035 	dest.s_addr = 0;
1036 	if (!srcrt && V_ipsendredirects &&
1037 	    ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
1038 		struct nhop_object *nh;
1039 
1040 		nh = ro.ro_nh;
1041 
1042 		if (nh != NULL && ((nh->nh_flags & (NHF_REDIRECT|NHF_DEFAULT)) == 0)) {
1043 			struct in_ifaddr *nh_ia = (struct in_ifaddr *)(nh->nh_ifa);
1044 			u_long src = ntohl(ip->ip_src.s_addr);
1045 
1046 			if (nh_ia != NULL &&
1047 			    (src & nh_ia->ia_subnetmask) == nh_ia->ia_subnet) {
1048 				/* Router requirements says to only send host redirects */
1049 				type = ICMP_REDIRECT;
1050 				code = ICMP_REDIRECT_HOST;
1051 				if (nh->nh_flags & NHF_GATEWAY) {
1052 				    if (nh->gw_sa.sa_family == AF_INET)
1053 					dest.s_addr = nh->gw4_sa.sin_addr.s_addr;
1054 				    else /* Do not redirect in case gw is AF_INET6 */
1055 					type = 0;
1056 				} else
1057 					dest.s_addr = ip->ip_dst.s_addr;
1058 			}
1059 		}
1060 	}
1061 
1062 	error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
1063 
1064 	if (error == EMSGSIZE && ro.ro_nh)
1065 		mtu = ro.ro_nh->nh_mtu;
1066 	RO_NHFREE(&ro);
1067 
1068 	if (error)
1069 		IPSTAT_INC(ips_cantforward);
1070 	else {
1071 		IPSTAT_INC(ips_forward);
1072 		if (type)
1073 			IPSTAT_INC(ips_redirectsent);
1074 		else {
1075 			if (mcopy)
1076 				m_freem(mcopy);
1077 			return;
1078 		}
1079 	}
1080 	if (mcopy == NULL)
1081 		return;
1082 
1083 	switch (error) {
1084 	case 0:				/* forwarded, but need redirect */
1085 		/* type, code set above */
1086 		break;
1087 
1088 	case ENETUNREACH:
1089 	case EHOSTUNREACH:
1090 	case ENETDOWN:
1091 	case EHOSTDOWN:
1092 	default:
1093 		type = ICMP_UNREACH;
1094 		code = ICMP_UNREACH_HOST;
1095 		break;
1096 
1097 	case EMSGSIZE:
1098 		type = ICMP_UNREACH;
1099 		code = ICMP_UNREACH_NEEDFRAG;
1100 		/*
1101 		 * If the MTU was set before make sure we are below the
1102 		 * interface MTU.
1103 		 * If the MTU wasn't set before use the interface mtu or
1104 		 * fall back to the next smaller mtu step compared to the
1105 		 * current packet size.
1106 		 */
1107 		if (mtu != 0) {
1108 			if (ia != NULL)
1109 				mtu = min(mtu, ia->ia_ifp->if_mtu);
1110 		} else {
1111 			if (ia != NULL)
1112 				mtu = ia->ia_ifp->if_mtu;
1113 			else
1114 				mtu = ip_next_mtu(ntohs(ip->ip_len), 0);
1115 		}
1116 		IPSTAT_INC(ips_cantfrag);
1117 		break;
1118 
1119 	case ENOBUFS:
1120 	case EACCES:			/* ipfw denied packet */
1121 		m_freem(mcopy);
1122 		return;
1123 	}
1124 	icmp_error(mcopy, type, code, dest.s_addr, mtu);
1125 }
1126 
1127 #define	CHECK_SO_CT(sp, ct) \
1128     (((sp->so_options & SO_TIMESTAMP) && (sp->so_ts_clock == ct)) ? 1 : 0)
1129 
1130 void
1131 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1132     struct mbuf *m)
1133 {
1134 	bool stamped;
1135 
1136 	stamped = false;
1137 	if ((inp->inp_socket->so_options & SO_BINTIME) ||
1138 	    CHECK_SO_CT(inp->inp_socket, SO_TS_BINTIME)) {
1139 		struct bintime boottimebin, bt;
1140 		struct timespec ts1;
1141 
1142 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1143 		    M_TSTMP)) {
1144 			mbuf_tstmp2timespec(m, &ts1);
1145 			timespec2bintime(&ts1, &bt);
1146 			getboottimebin(&boottimebin);
1147 			bintime_add(&bt, &boottimebin);
1148 		} else {
1149 			bintime(&bt);
1150 		}
1151 		*mp = sbcreatecontrol(&bt, sizeof(bt), SCM_BINTIME,
1152 		    SOL_SOCKET, M_NOWAIT);
1153 		if (*mp != NULL) {
1154 			mp = &(*mp)->m_next;
1155 			stamped = true;
1156 		}
1157 	}
1158 	if (CHECK_SO_CT(inp->inp_socket, SO_TS_REALTIME_MICRO)) {
1159 		struct bintime boottimebin, bt1;
1160 		struct timespec ts1;
1161 		struct timeval tv;
1162 
1163 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1164 		    M_TSTMP)) {
1165 			mbuf_tstmp2timespec(m, &ts1);
1166 			timespec2bintime(&ts1, &bt1);
1167 			getboottimebin(&boottimebin);
1168 			bintime_add(&bt1, &boottimebin);
1169 			bintime2timeval(&bt1, &tv);
1170 		} else {
1171 			microtime(&tv);
1172 		}
1173 		*mp = sbcreatecontrol((caddr_t)&tv, sizeof(tv), SCM_TIMESTAMP,
1174 		    SOL_SOCKET, M_NOWAIT);
1175 		if (*mp != NULL) {
1176 			mp = &(*mp)->m_next;
1177 			stamped = true;
1178 		}
1179 	} else if (CHECK_SO_CT(inp->inp_socket, SO_TS_REALTIME)) {
1180 		struct bintime boottimebin;
1181 		struct timespec ts, ts1;
1182 
1183 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1184 		    M_TSTMP)) {
1185 			mbuf_tstmp2timespec(m, &ts);
1186 			getboottimebin(&boottimebin);
1187 			bintime2timespec(&boottimebin, &ts1);
1188 			timespecadd(&ts, &ts1, &ts);
1189 		} else {
1190 			nanotime(&ts);
1191 		}
1192 		*mp = sbcreatecontrol(&ts, sizeof(ts), SCM_REALTIME,
1193 		    SOL_SOCKET, M_NOWAIT);
1194 		if (*mp != NULL) {
1195 			mp = &(*mp)->m_next;
1196 			stamped = true;
1197 		}
1198 	} else if (CHECK_SO_CT(inp->inp_socket, SO_TS_MONOTONIC)) {
1199 		struct timespec ts;
1200 
1201 		if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1202 		    M_TSTMP))
1203 			mbuf_tstmp2timespec(m, &ts);
1204 		else
1205 			nanouptime(&ts);
1206 		*mp = sbcreatecontrol(&ts, sizeof(ts), SCM_MONOTONIC,
1207 		    SOL_SOCKET, M_NOWAIT);
1208 		if (*mp != NULL) {
1209 			mp = &(*mp)->m_next;
1210 			stamped = true;
1211 		}
1212 	}
1213 	if (stamped && (m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
1214 	    M_TSTMP)) {
1215 		struct sock_timestamp_info sti;
1216 
1217 		bzero(&sti, sizeof(sti));
1218 		sti.st_info_flags = ST_INFO_HW;
1219 		if ((m->m_flags & M_TSTMP_HPREC) != 0)
1220 			sti.st_info_flags |= ST_INFO_HW_HPREC;
1221 		*mp = sbcreatecontrol(&sti, sizeof(sti), SCM_TIME_INFO,
1222 		    SOL_SOCKET, M_NOWAIT);
1223 		if (*mp != NULL)
1224 			mp = &(*mp)->m_next;
1225 	}
1226 	if (inp->inp_flags & INP_RECVDSTADDR) {
1227 		*mp = sbcreatecontrol(&ip->ip_dst, sizeof(struct in_addr),
1228 		    IP_RECVDSTADDR, IPPROTO_IP, M_NOWAIT);
1229 		if (*mp)
1230 			mp = &(*mp)->m_next;
1231 	}
1232 	if (inp->inp_flags & INP_RECVTTL) {
1233 		*mp = sbcreatecontrol(&ip->ip_ttl, sizeof(u_char), IP_RECVTTL,
1234 		    IPPROTO_IP, M_NOWAIT);
1235 		if (*mp)
1236 			mp = &(*mp)->m_next;
1237 	}
1238 #ifdef notyet
1239 	/* XXX
1240 	 * Moving these out of udp_input() made them even more broken
1241 	 * than they already were.
1242 	 */
1243 	/* options were tossed already */
1244 	if (inp->inp_flags & INP_RECVOPTS) {
1245 		*mp = sbcreatecontrol(opts_deleted_above,
1246 		    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP, M_NOWAIT);
1247 		if (*mp)
1248 			mp = &(*mp)->m_next;
1249 	}
1250 	/* ip_srcroute doesn't do what we want here, need to fix */
1251 	if (inp->inp_flags & INP_RECVRETOPTS) {
1252 		*mp = sbcreatecontrol(ip_srcroute(m), sizeof(struct in_addr),
1253 		    IP_RECVRETOPTS, IPPROTO_IP, M_NOWAIT);
1254 		if (*mp)
1255 			mp = &(*mp)->m_next;
1256 	}
1257 #endif
1258 	if (inp->inp_flags & INP_RECVIF) {
1259 		struct ifnet *ifp;
1260 		struct sdlbuf {
1261 			struct sockaddr_dl sdl;
1262 			u_char	pad[32];
1263 		} sdlbuf;
1264 		struct sockaddr_dl *sdp;
1265 		struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
1266 
1267 		if ((ifp = m->m_pkthdr.rcvif)) {
1268 			sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
1269 			/*
1270 			 * Change our mind and don't try copy.
1271 			 */
1272 			if (sdp->sdl_family != AF_LINK ||
1273 			    sdp->sdl_len > sizeof(sdlbuf)) {
1274 				goto makedummy;
1275 			}
1276 			bcopy(sdp, sdl2, sdp->sdl_len);
1277 		} else {
1278 makedummy:
1279 			sdl2->sdl_len =
1280 			    offsetof(struct sockaddr_dl, sdl_data[0]);
1281 			sdl2->sdl_family = AF_LINK;
1282 			sdl2->sdl_index = 0;
1283 			sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
1284 		}
1285 		*mp = sbcreatecontrol(sdl2, sdl2->sdl_len, IP_RECVIF,
1286 		    IPPROTO_IP, M_NOWAIT);
1287 		if (*mp)
1288 			mp = &(*mp)->m_next;
1289 	}
1290 	if (inp->inp_flags & INP_RECVTOS) {
1291 		*mp = sbcreatecontrol(&ip->ip_tos, sizeof(u_char), IP_RECVTOS,
1292 		    IPPROTO_IP, M_NOWAIT);
1293 		if (*mp)
1294 			mp = &(*mp)->m_next;
1295 	}
1296 
1297 	if (inp->inp_flags2 & INP_RECVFLOWID) {
1298 		uint32_t flowid, flow_type;
1299 
1300 		flowid = m->m_pkthdr.flowid;
1301 		flow_type = M_HASHTYPE_GET(m);
1302 
1303 		/*
1304 		 * XXX should handle the failure of one or the
1305 		 * other - don't populate both?
1306 		 */
1307 		*mp = sbcreatecontrol(&flowid, sizeof(uint32_t), IP_FLOWID,
1308 		    IPPROTO_IP, M_NOWAIT);
1309 		if (*mp)
1310 			mp = &(*mp)->m_next;
1311 		*mp = sbcreatecontrol(&flow_type, sizeof(uint32_t),
1312 		    IP_FLOWTYPE, IPPROTO_IP, M_NOWAIT);
1313 		if (*mp)
1314 			mp = &(*mp)->m_next;
1315 	}
1316 
1317 #ifdef	RSS
1318 	if (inp->inp_flags2 & INP_RECVRSSBUCKETID) {
1319 		uint32_t flowid, flow_type;
1320 		uint32_t rss_bucketid;
1321 
1322 		flowid = m->m_pkthdr.flowid;
1323 		flow_type = M_HASHTYPE_GET(m);
1324 
1325 		if (rss_hash2bucket(flowid, flow_type, &rss_bucketid) == 0) {
1326 			*mp = sbcreatecontrol(&rss_bucketid, sizeof(uint32_t),
1327 			    IP_RSSBUCKETID, IPPROTO_IP, M_NOWAIT);
1328 			if (*mp)
1329 				mp = &(*mp)->m_next;
1330 		}
1331 	}
1332 #endif
1333 }
1334 
1335 /*
1336  * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
1337  * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
1338  * locking.  This code remains in ip_input.c as ip_mroute.c is optionally
1339  * compiled.
1340  */
1341 VNET_DEFINE_STATIC(int, ip_rsvp_on);
1342 VNET_DEFINE(struct socket *, ip_rsvpd);
1343 
1344 #define	V_ip_rsvp_on		VNET(ip_rsvp_on)
1345 
1346 int
1347 ip_rsvp_init(struct socket *so)
1348 {
1349 
1350 	if (V_ip_rsvpd != NULL)
1351 		return EADDRINUSE;
1352 
1353 	V_ip_rsvpd = so;
1354 	/*
1355 	 * This may seem silly, but we need to be sure we don't over-increment
1356 	 * the RSVP counter, in case something slips up.
1357 	 */
1358 	if (!V_ip_rsvp_on) {
1359 		V_ip_rsvp_on = 1;
1360 		V_rsvp_on++;
1361 	}
1362 
1363 	return 0;
1364 }
1365 
1366 int
1367 ip_rsvp_done(void)
1368 {
1369 
1370 	V_ip_rsvpd = NULL;
1371 	/*
1372 	 * This may seem silly, but we need to be sure we don't over-decrement
1373 	 * the RSVP counter, in case something slips up.
1374 	 */
1375 	if (V_ip_rsvp_on) {
1376 		V_ip_rsvp_on = 0;
1377 		V_rsvp_on--;
1378 	}
1379 	return 0;
1380 }
1381 
1382 int
1383 rsvp_input(struct mbuf **mp, int *offp, int proto)
1384 {
1385 	struct mbuf *m;
1386 
1387 	m = *mp;
1388 	*mp = NULL;
1389 
1390 	if (rsvp_input_p) { /* call the real one if loaded */
1391 		*mp = m;
1392 		rsvp_input_p(mp, offp, proto);
1393 		return (IPPROTO_DONE);
1394 	}
1395 
1396 	/* Can still get packets with rsvp_on = 0 if there is a local member
1397 	 * of the group to which the RSVP packet is addressed.  But in this
1398 	 * case we want to throw the packet away.
1399 	 */
1400 
1401 	if (!V_rsvp_on) {
1402 		m_freem(m);
1403 		return (IPPROTO_DONE);
1404 	}
1405 
1406 	if (V_ip_rsvpd != NULL) {
1407 		*mp = m;
1408 		rip_input(mp, offp, proto);
1409 		return (IPPROTO_DONE);
1410 	}
1411 	/* Drop the packet */
1412 	m_freem(m);
1413 	return (IPPROTO_DONE);
1414 }
1415