ip_input.c revision 1.349 1 /* $NetBSD: ip_input.c,v 1.349 2017/02/07 02:38:08 ozaki-r Exp $ */
2
3 /*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * 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 project 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 PROJECT 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 PROJECT 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 /*-
33 * Copyright (c) 1998 The NetBSD Foundation, Inc.
34 * All rights reserved.
35 *
36 * This code is derived from software contributed to The NetBSD Foundation
37 * by Public Access Networks Corporation ("Panix"). It was developed under
38 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
50 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
51 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
52 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
53 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
54 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
55 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
56 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
57 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
58 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
59 * POSSIBILITY OF SUCH DAMAGE.
60 */
61
62 /*
63 * Copyright (c) 1982, 1986, 1988, 1993
64 * The Regents of the University of California. All rights reserved.
65 *
66 * Redistribution and use in source and binary forms, with or without
67 * modification, are permitted provided that the following conditions
68 * are met:
69 * 1. Redistributions of source code must retain the above copyright
70 * notice, this list of conditions and the following disclaimer.
71 * 2. Redistributions in binary form must reproduce the above copyright
72 * notice, this list of conditions and the following disclaimer in the
73 * documentation and/or other materials provided with the distribution.
74 * 3. Neither the name of the University nor the names of its contributors
75 * may be used to endorse or promote products derived from this software
76 * without specific prior written permission.
77 *
78 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
79 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
80 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
81 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
82 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
83 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
84 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
85 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
86 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
87 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
88 * SUCH DAMAGE.
89 *
90 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
91 */
92
93 #include <sys/cdefs.h>
94 __KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.349 2017/02/07 02:38:08 ozaki-r Exp $");
95
96 #ifdef _KERNEL_OPT
97 #include "opt_inet.h"
98 #include "opt_compat_netbsd.h"
99 #include "opt_gateway.h"
100 #include "opt_ipsec.h"
101 #include "opt_mrouting.h"
102 #include "opt_mbuftrace.h"
103 #include "opt_inet_csum.h"
104 #include "opt_net_mpsafe.h"
105 #endif
106
107 #include "arp.h"
108
109 #include <sys/param.h>
110 #include <sys/systm.h>
111 #include <sys/cpu.h>
112 #include <sys/mbuf.h>
113 #include <sys/domain.h>
114 #include <sys/protosw.h>
115 #include <sys/socket.h>
116 #include <sys/socketvar.h>
117 #include <sys/errno.h>
118 #include <sys/time.h>
119 #include <sys/kernel.h>
120 #include <sys/pool.h>
121 #include <sys/sysctl.h>
122 #include <sys/kauth.h>
123
124 #include <net/if.h>
125 #include <net/if_dl.h>
126 #include <net/route.h>
127 #include <net/pktqueue.h>
128 #include <net/pfil.h>
129
130 #include <netinet/in.h>
131 #include <netinet/in_systm.h>
132 #include <netinet/ip.h>
133 #include <netinet/in_pcb.h>
134 #include <netinet/in_proto.h>
135 #include <netinet/in_var.h>
136 #include <netinet/ip_var.h>
137 #include <netinet/ip_private.h>
138 #include <netinet/ip_icmp.h>
139 /* just for gif_ttl */
140 #include <netinet/in_gif.h>
141 #include "gif.h"
142 #include <net/if_gre.h>
143 #include "gre.h"
144
145 #ifdef MROUTING
146 #include <netinet/ip_mroute.h>
147 #endif
148 #include <netinet/portalgo.h>
149
150 #ifdef IPSEC
151 #include <netipsec/ipsec.h>
152 #endif
153
154 #ifndef IPFORWARDING
155 #ifdef GATEWAY
156 #define IPFORWARDING 1 /* forward IP packets not for us */
157 #else /* GATEWAY */
158 #define IPFORWARDING 0 /* don't forward IP packets not for us */
159 #endif /* GATEWAY */
160 #endif /* IPFORWARDING */
161 #ifndef IPSENDREDIRECTS
162 #define IPSENDREDIRECTS 1
163 #endif
164 #ifndef IPFORWSRCRT
165 #define IPFORWSRCRT 1 /* forward source-routed packets */
166 #endif
167 #ifndef IPALLOWSRCRT
168 #define IPALLOWSRCRT 1 /* allow source-routed packets */
169 #endif
170 #ifndef IPMTUDISC
171 #define IPMTUDISC 1
172 #endif
173 #ifndef IPMTUDISCTIMEOUT
174 #define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */
175 #endif
176
177 #ifdef COMPAT_50
178 #include <compat/sys/time.h>
179 #include <compat/sys/socket.h>
180 #endif
181
182 /*
183 * Note: DIRECTED_BROADCAST is handled this way so that previous
184 * configuration using this option will Just Work.
185 */
186 #ifndef IPDIRECTEDBCAST
187 #ifdef DIRECTED_BROADCAST
188 #define IPDIRECTEDBCAST 1
189 #else
190 #define IPDIRECTEDBCAST 0
191 #endif /* DIRECTED_BROADCAST */
192 #endif /* IPDIRECTEDBCAST */
193 int ipforwarding = IPFORWARDING;
194 int ipsendredirects = IPSENDREDIRECTS;
195 int ip_defttl = IPDEFTTL;
196 int ip_forwsrcrt = IPFORWSRCRT;
197 int ip_directedbcast = IPDIRECTEDBCAST;
198 int ip_allowsrcrt = IPALLOWSRCRT;
199 int ip_mtudisc = IPMTUDISC;
200 int ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
201 #ifdef DIAGNOSTIC
202 int ipprintfs = 0;
203 #endif
204
205 int ip_do_randomid = 0;
206
207 /*
208 * XXX - Setting ip_checkinterface mostly implements the receive side of
209 * the Strong ES model described in RFC 1122, but since the routing table
210 * and transmit implementation do not implement the Strong ES model,
211 * setting this to 1 results in an odd hybrid.
212 *
213 * XXX - ip_checkinterface currently must be disabled if you use ipnat
214 * to translate the destination address to another local interface.
215 *
216 * XXX - ip_checkinterface must be disabled if you add IP aliases
217 * to the loopback interface instead of the interface where the
218 * packets for those addresses are received.
219 */
220 static int ip_checkinterface __read_mostly = 0;
221
222 struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
223
224 pktqueue_t * ip_pktq __read_mostly;
225 pfil_head_t * inet_pfil_hook __read_mostly;
226 ipid_state_t * ip_ids __read_mostly;
227 percpu_t * ipstat_percpu __read_mostly;
228
229 static percpu_t *ipforward_rt_percpu __cacheline_aligned;
230
231 uint16_t ip_id;
232
233 #ifdef INET_CSUM_COUNTERS
234 #include <sys/device.h>
235
236 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
237 NULL, "inet", "hwcsum bad");
238 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
239 NULL, "inet", "hwcsum ok");
240 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
241 NULL, "inet", "swcsum");
242
243 #define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++
244
245 EVCNT_ATTACH_STATIC(ip_hwcsum_bad);
246 EVCNT_ATTACH_STATIC(ip_hwcsum_ok);
247 EVCNT_ATTACH_STATIC(ip_swcsum);
248
249 #else
250
251 #define INET_CSUM_COUNTER_INCR(ev) /* nothing */
252
253 #endif /* INET_CSUM_COUNTERS */
254
255 /*
256 * We need to save the IP options in case a protocol wants to respond
257 * to an incoming packet over the same route if the packet got here
258 * using IP source routing. This allows connection establishment and
259 * maintenance when the remote end is on a network that is not known
260 * to us.
261 */
262
263 static int ip_nhops = 0;
264
265 static struct ip_srcrt {
266 struct in_addr dst; /* final destination */
267 char nop; /* one NOP to align */
268 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
269 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
270 } ip_srcrt;
271
272 static int ip_drainwanted;
273
274 struct sockaddr_in ipaddr = {
275 .sin_len = sizeof(ipaddr),
276 .sin_family = AF_INET,
277 };
278
279 static void save_rte(u_char *, struct in_addr);
280
281 #ifdef MBUFTRACE
282 struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx");
283 struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx");
284 #endif
285
286 static void ipintr(void *);
287 static void ip_input(struct mbuf *);
288 static void ip_forward(struct mbuf *, int, struct ifnet *);
289 static bool ip_dooptions(struct mbuf *);
290 static struct in_ifaddr *ip_rtaddr(struct in_addr, struct psref *);
291 static void sysctl_net_inet_ip_setup(struct sysctllog **);
292
293 static struct in_ifaddr *ip_match_our_address(struct ifnet *, struct ip *,
294 int *);
295 static struct in_ifaddr *ip_match_our_address_broadcast(struct ifnet *,
296 struct ip *);
297
298 #ifdef NET_MPSAFE
299 #define SOFTNET_LOCK() mutex_enter(softnet_lock)
300 #define SOFTNET_UNLOCK() mutex_exit(softnet_lock)
301 #else
302 #define SOFTNET_LOCK() KASSERT(mutex_owned(softnet_lock))
303 #define SOFTNET_UNLOCK() KASSERT(mutex_owned(softnet_lock))
304 #endif
305
306 /*
307 * IP initialization: fill in IP protocol switch table.
308 * All protocols not implemented in kernel go to raw IP protocol handler.
309 */
310 void
311 ip_init(void)
312 {
313 const struct protosw *pr;
314
315 in_init();
316 sysctl_net_inet_ip_setup(NULL);
317
318 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
319 KASSERT(pr != NULL);
320
321 ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL);
322 KASSERT(ip_pktq != NULL);
323
324 for (u_int i = 0; i < IPPROTO_MAX; i++) {
325 ip_protox[i] = pr - inetsw;
326 }
327 for (pr = inetdomain.dom_protosw;
328 pr < inetdomain.dom_protoswNPROTOSW; pr++)
329 if (pr->pr_domain->dom_family == PF_INET &&
330 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
331 ip_protox[pr->pr_protocol] = pr - inetsw;
332
333 ip_reass_init();
334
335 ip_ids = ip_id_init();
336 ip_id = time_uptime & 0xfffff;
337
338 #ifdef GATEWAY
339 ipflow_init();
340 #endif
341
342 /* Register our Packet Filter hook. */
343 inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET);
344 KASSERT(inet_pfil_hook != NULL);
345
346 #ifdef MBUFTRACE
347 MOWNER_ATTACH(&ip_tx_mowner);
348 MOWNER_ATTACH(&ip_rx_mowner);
349 #endif /* MBUFTRACE */
350
351 ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS);
352
353 ipforward_rt_percpu = percpu_alloc(sizeof(struct route));
354 if (ipforward_rt_percpu == NULL)
355 panic("failed to allocate ipforward_rt_percpu");
356 }
357
358 static struct in_ifaddr *
359 ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch)
360 {
361 struct in_ifaddr *ia = NULL;
362 int checkif;
363
364 /*
365 * Enable a consistency check between the destination address
366 * and the arrival interface for a unicast packet (the RFC 1122
367 * strong ES model) if IP forwarding is disabled and the packet
368 * is not locally generated.
369 *
370 * XXX - Checking also should be disabled if the destination
371 * address is ipnat'ed to a different interface.
372 *
373 * XXX - Checking is incompatible with IP aliases added
374 * to the loopback interface instead of the interface where
375 * the packets are received.
376 *
377 * XXX - We need to add a per ifaddr flag for this so that
378 * we get finer grain control.
379 */
380 checkif = ip_checkinterface && (ipforwarding == 0) &&
381 (ifp->if_flags & IFF_LOOPBACK) == 0;
382
383 IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) {
384 if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
385 if (ia->ia4_flags & IN_IFF_NOTREADY)
386 continue;
387 if (checkif && ia->ia_ifp != ifp)
388 continue;
389 if ((ia->ia_ifp->if_flags & IFF_UP) != 0 &&
390 (ia->ia4_flags & IN_IFF_DETACHED) == 0)
391 break;
392 else
393 (*downmatch)++;
394 }
395 }
396
397 return ia;
398 }
399
400 static struct in_ifaddr *
401 ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip)
402 {
403 struct in_ifaddr *ia = NULL;
404 struct ifaddr *ifa;
405
406 IFADDR_READER_FOREACH(ifa, ifp) {
407 if (ifa->ifa_addr->sa_family != AF_INET)
408 continue;
409 ia = ifatoia(ifa);
410 if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
411 continue;
412 if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
413 in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
414 /*
415 * Look for all-0's host part (old broadcast addr),
416 * either for subnet or net.
417 */
418 ip->ip_dst.s_addr == ia->ia_subnet ||
419 ip->ip_dst.s_addr == ia->ia_net)
420 goto matched;
421 /*
422 * An interface with IP address zero accepts
423 * all packets that arrive on that interface.
424 */
425 if (in_nullhost(ia->ia_addr.sin_addr))
426 goto matched;
427 }
428 ia = NULL;
429
430 matched:
431 return ia;
432 }
433
434 /*
435 * IP software interrupt routine.
436 */
437 static void
438 ipintr(void *arg __unused)
439 {
440 struct mbuf *m;
441
442 KASSERT(cpu_softintr_p());
443
444 #ifndef NET_MPSAFE
445 mutex_enter(softnet_lock);
446 #endif
447 while ((m = pktq_dequeue(ip_pktq)) != NULL) {
448 ip_input(m);
449 }
450 #ifndef NET_MPSAFE
451 mutex_exit(softnet_lock);
452 #endif
453 }
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 static void
460 ip_input(struct mbuf *m)
461 {
462 struct ip *ip = NULL;
463 struct in_ifaddr *ia = NULL;
464 int hlen = 0, len;
465 int downmatch;
466 int srcrt = 0;
467 ifnet_t *ifp;
468 struct psref psref;
469 int s;
470
471 KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software "
472 "interrupt handler; synchronization assumptions violated");
473
474 MCLAIM(m, &ip_rx_mowner);
475 KASSERT((m->m_flags & M_PKTHDR) != 0);
476
477 ifp = m_get_rcvif_psref(m, &psref);
478 if (__predict_false(ifp == NULL))
479 goto out;
480
481 /*
482 * If no IP addresses have been set yet but the interfaces
483 * are receiving, can't do anything with incoming packets yet.
484 * Note: we pre-check without locks held.
485 */
486 if (IN_ADDRLIST_READER_EMPTY())
487 goto out;
488 IP_STATINC(IP_STAT_TOTAL);
489
490 /*
491 * If the IP header is not aligned, slurp it up into a new
492 * mbuf with space for link headers, in the event we forward
493 * it. Otherwise, if it is aligned, make sure the entire
494 * base IP header is in the first mbuf of the chain.
495 */
496 if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
497 if ((m = m_copyup(m, sizeof(struct ip),
498 (max_linkhdr + 3) & ~3)) == NULL) {
499 /* XXXJRT new stat, please */
500 IP_STATINC(IP_STAT_TOOSMALL);
501 goto out;
502 }
503 } else if (__predict_false(m->m_len < sizeof (struct ip))) {
504 if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
505 IP_STATINC(IP_STAT_TOOSMALL);
506 goto out;
507 }
508 }
509 ip = mtod(m, struct ip *);
510 if (ip->ip_v != IPVERSION) {
511 IP_STATINC(IP_STAT_BADVERS);
512 goto out;
513 }
514 hlen = ip->ip_hl << 2;
515 if (hlen < sizeof(struct ip)) { /* minimum header length */
516 IP_STATINC(IP_STAT_BADHLEN);
517 goto out;
518 }
519 if (hlen > m->m_len) {
520 if ((m = m_pullup(m, hlen)) == NULL) {
521 IP_STATINC(IP_STAT_BADHLEN);
522 goto out;
523 }
524 ip = mtod(m, struct ip *);
525 }
526
527 /*
528 * RFC1122: packets with a multicast source address are
529 * not allowed.
530 */
531 if (IN_MULTICAST(ip->ip_src.s_addr)) {
532 IP_STATINC(IP_STAT_BADADDR);
533 goto out;
534 }
535
536 /* 127/8 must not appear on wire - RFC1122 */
537 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
538 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
539 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
540 IP_STATINC(IP_STAT_BADADDR);
541 goto out;
542 }
543 }
544
545 switch (m->m_pkthdr.csum_flags &
546 ((ifp->if_csum_flags_rx & M_CSUM_IPv4) |
547 M_CSUM_IPv4_BAD)) {
548 case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
549 INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
550 IP_STATINC(IP_STAT_BADSUM);
551 goto out;
552
553 case M_CSUM_IPv4:
554 /* Checksum was okay. */
555 INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
556 break;
557
558 default:
559 /*
560 * Must compute it ourselves. Maybe skip checksum on
561 * loopback interfaces.
562 */
563 if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) ||
564 ip_do_loopback_cksum)) {
565 INET_CSUM_COUNTER_INCR(&ip_swcsum);
566 if (in_cksum(m, hlen) != 0) {
567 IP_STATINC(IP_STAT_BADSUM);
568 goto out;
569 }
570 }
571 break;
572 }
573
574 /* Retrieve the packet length. */
575 len = ntohs(ip->ip_len);
576
577 /*
578 * Check for additional length bogosity
579 */
580 if (len < hlen) {
581 IP_STATINC(IP_STAT_BADLEN);
582 goto out;
583 }
584
585 /*
586 * Check that the amount of data in the buffers
587 * is as at least much as the IP header would have us expect.
588 * Trim mbufs if longer than we expect.
589 * Drop packet if shorter than we expect.
590 */
591 if (m->m_pkthdr.len < len) {
592 IP_STATINC(IP_STAT_TOOSHORT);
593 goto out;
594 }
595 if (m->m_pkthdr.len > len) {
596 if (m->m_len == m->m_pkthdr.len) {
597 m->m_len = len;
598 m->m_pkthdr.len = len;
599 } else
600 m_adj(m, len - m->m_pkthdr.len);
601 }
602
603 /*
604 * Assume that we can create a fast-forward IP flow entry
605 * based on this packet.
606 */
607 m->m_flags |= M_CANFASTFWD;
608
609 /*
610 * Run through list of hooks for input packets. If there are any
611 * filters which require that additional packets in the flow are
612 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
613 * Note that filters must _never_ set this flag, as another filter
614 * in the list may have previously cleared it.
615 */
616 #if defined(IPSEC)
617 if (!ipsec_used || !ipsec_indone(m))
618 #else
619 if (1)
620 #endif
621 {
622 struct in_addr odst = ip->ip_dst;
623 bool freed;
624
625 freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0;
626 if (freed || m == NULL) {
627 m = NULL;
628 goto out;
629 }
630 ip = mtod(m, struct ip *);
631 hlen = ip->ip_hl << 2;
632
633 /*
634 * XXX The setting of "srcrt" here is to prevent ip_forward()
635 * from generating ICMP redirects for packets that have
636 * been redirected by a hook back out on to the same LAN that
637 * they came from and is not an indication that the packet
638 * is being inffluenced by source routing options. This
639 * allows things like
640 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp"
641 * where tlp0 is both on the 1.1.1.0/24 network and is the
642 * default route for hosts on 1.1.1.0/24. Of course this
643 * also requires a "map tlp0 ..." to complete the story.
644 * One might argue whether or not this kind of network config.
645 * should be supported in this manner...
646 */
647 srcrt = (odst.s_addr != ip->ip_dst.s_addr);
648 }
649
650 #ifdef ALTQ
651 /* XXX Temporary until ALTQ is changed to use a pfil hook */
652 if (altq_input) {
653 SOFTNET_LOCK();
654 if ((*altq_input)(m, AF_INET) == 0) {
655 /* Packet dropped by traffic conditioner. */
656 SOFTNET_UNLOCK();
657 m = NULL;
658 goto out;
659 }
660 SOFTNET_UNLOCK();
661 }
662 #endif
663
664 /*
665 * Process options and, if not destined for us,
666 * ship it on. ip_dooptions returns 1 when an
667 * error was detected (causing an icmp message
668 * to be sent and the original packet to be freed).
669 */
670 ip_nhops = 0; /* for source routed packets */
671 if (hlen > sizeof (struct ip) && ip_dooptions(m)) {
672 m = NULL;
673 goto out;
674 }
675
676 /*
677 * Check our list of addresses, to see if the packet is for us.
678 *
679 * Traditional 4.4BSD did not consult IFF_UP at all.
680 * The behavior here is to treat addresses on !IFF_UP interface
681 * or IN_IFF_NOTREADY addresses as not mine.
682 */
683 downmatch = 0;
684 s = pserialize_read_enter();
685 ia = ip_match_our_address(ifp, ip, &downmatch);
686 if (ia != NULL) {
687 pserialize_read_exit(s);
688 goto ours;
689 }
690
691 if (ifp->if_flags & IFF_BROADCAST) {
692 ia = ip_match_our_address_broadcast(ifp, ip);
693 if (ia != NULL) {
694 pserialize_read_exit(s);
695 goto ours;
696 }
697 }
698 pserialize_read_exit(s);
699
700 if (IN_MULTICAST(ip->ip_dst.s_addr)) {
701 #ifdef MROUTING
702 extern struct socket *ip_mrouter;
703
704 if (ip_mrouter) {
705 /*
706 * If we are acting as a multicast router, all
707 * incoming multicast packets are passed to the
708 * kernel-level multicast forwarding function.
709 * The packet is returned (relatively) intact; if
710 * ip_mforward() returns a non-zero value, the packet
711 * must be discarded, else it may be accepted below.
712 *
713 * (The IP ident field is put in the same byte order
714 * as expected when ip_mforward() is called from
715 * ip_output().)
716 */
717 SOFTNET_LOCK();
718 if (ip_mforward(m, ifp) != 0) {
719 SOFTNET_UNLOCK();
720 IP_STATINC(IP_STAT_CANTFORWARD);
721 goto out;
722 }
723 SOFTNET_UNLOCK();
724
725 /*
726 * The process-level routing demon needs to receive
727 * all multicast IGMP packets, whether or not this
728 * host belongs to their destination groups.
729 */
730 if (ip->ip_p == IPPROTO_IGMP) {
731 goto ours;
732 }
733 IP_STATINC(IP_STAT_CANTFORWARD);
734 }
735 #endif
736 /*
737 * See if we belong to the destination multicast group on the
738 * arrival interface.
739 */
740 if (!in_multi_group(ip->ip_dst, ifp, 0)) {
741 IP_STATINC(IP_STAT_CANTFORWARD);
742 goto out;
743 }
744 goto ours;
745 }
746 if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
747 in_nullhost(ip->ip_dst))
748 goto ours;
749
750 /*
751 * Not for us; forward if possible and desirable.
752 */
753 if (ipforwarding == 0) {
754 m_put_rcvif_psref(ifp, &psref);
755 IP_STATINC(IP_STAT_CANTFORWARD);
756 m_freem(m);
757 } else {
758 /*
759 * If ip_dst matched any of my address on !IFF_UP interface,
760 * and there's no IFF_UP interface that matches ip_dst,
761 * send icmp unreach. Forwarding it will result in in-kernel
762 * forwarding loop till TTL goes to 0.
763 */
764 if (downmatch) {
765 m_put_rcvif_psref(ifp, &psref);
766 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
767 IP_STATINC(IP_STAT_CANTFORWARD);
768 return;
769 }
770 #ifdef IPSEC
771 /* Perform IPsec, if any. */
772 if (ipsec_used) {
773 SOFTNET_LOCK();
774 if (ipsec4_input(m, IP_FORWARDING |
775 (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) {
776 SOFTNET_UNLOCK();
777 goto out;
778 }
779 SOFTNET_UNLOCK();
780 }
781 #endif
782 ip_forward(m, srcrt, ifp);
783 m_put_rcvif_psref(ifp, &psref);
784 }
785 return;
786
787 ours:
788 m_put_rcvif_psref(ifp, &psref);
789 ifp = NULL;
790
791 /*
792 * If offset or IP_MF are set, must reassemble.
793 */
794 if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
795 /*
796 * Pass to IP reassembly mechanism.
797 */
798 if (ip_reass_packet(&m, ip) != 0) {
799 /* Failed; invalid fragment(s) or packet. */
800 goto out;
801 }
802 if (m == NULL) {
803 /* More fragments should come; silently return. */
804 goto out;
805 }
806 /*
807 * Reassembly is done, we have the final packet.
808 * Updated cached data in local variable(s).
809 */
810 ip = mtod(m, struct ip *);
811 hlen = ip->ip_hl << 2;
812 }
813
814 #ifdef IPSEC
815 /*
816 * Enforce IPsec policy checking if we are seeing last header.
817 * Note that we do not visit this with protocols with PCB layer
818 * code - like UDP/TCP/raw IP.
819 */
820 if (ipsec_used &&
821 (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
822 SOFTNET_LOCK();
823 if (ipsec4_input(m, 0) != 0) {
824 SOFTNET_UNLOCK();
825 goto out;
826 }
827 SOFTNET_UNLOCK();
828 }
829 #endif
830
831 /*
832 * Switch out to protocol's input routine.
833 */
834 #if IFA_STATS
835 if (ia && ip) {
836 struct in_ifaddr *_ia;
837 /*
838 * Keep a reference from ip_match_our_address with psref
839 * is expensive, so explore ia here again.
840 */
841 s = pserialize_read_enter();
842 _ia = in_get_ia(ip->ip_dst);
843 _ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
844 pserialize_read_exit(s);
845 }
846 #endif
847 IP_STATINC(IP_STAT_DELIVERED);
848
849 const int off = hlen, nh = ip->ip_p;
850
851 SOFTNET_LOCK();
852 (*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
853 SOFTNET_UNLOCK();
854 return;
855
856 out:
857 m_put_rcvif_psref(ifp, &psref);
858 if (m != NULL)
859 m_freem(m);
860 }
861
862 /*
863 * IP timer processing.
864 */
865 void
866 ip_slowtimo(void)
867 {
868
869 #ifndef NET_MPSAFE
870 mutex_enter(softnet_lock);
871 KERNEL_LOCK(1, NULL);
872 #endif
873
874 ip_reass_slowtimo();
875
876 #ifndef NET_MPSAFE
877 KERNEL_UNLOCK_ONE(NULL);
878 mutex_exit(softnet_lock);
879 #endif
880 }
881
882 /*
883 * IP drain processing.
884 */
885 void
886 ip_drain(void)
887 {
888
889 KERNEL_LOCK(1, NULL);
890 ip_reass_drain();
891 KERNEL_UNLOCK_ONE(NULL);
892 }
893
894 /*
895 * ip_dooptions: perform option processing on a datagram, possibly discarding
896 * it if bad options are encountered, or forwarding it if source-routed.
897 *
898 * => Returns true if packet has been forwarded/freed.
899 * => Returns false if the packet should be processed further.
900 */
901 static bool
902 ip_dooptions(struct mbuf *m)
903 {
904 struct ip *ip = mtod(m, struct ip *);
905 u_char *cp, *cp0;
906 struct ip_timestamp *ipt;
907 struct in_ifaddr *ia;
908 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
909 struct in_addr dst;
910 n_time ntime;
911 struct ifaddr *ifa = NULL;
912 int s;
913
914 dst = ip->ip_dst;
915 cp = (u_char *)(ip + 1);
916 cnt = (ip->ip_hl << 2) - sizeof (struct ip);
917 for (; cnt > 0; cnt -= optlen, cp += optlen) {
918 opt = cp[IPOPT_OPTVAL];
919 if (opt == IPOPT_EOL)
920 break;
921 if (opt == IPOPT_NOP)
922 optlen = 1;
923 else {
924 if (cnt < IPOPT_OLEN + sizeof(*cp)) {
925 code = &cp[IPOPT_OLEN] - (u_char *)ip;
926 goto bad;
927 }
928 optlen = cp[IPOPT_OLEN];
929 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
930 code = &cp[IPOPT_OLEN] - (u_char *)ip;
931 goto bad;
932 }
933 }
934 switch (opt) {
935
936 default:
937 break;
938
939 /*
940 * Source routing with record.
941 * Find interface with current destination address.
942 * If none on this machine then drop if strictly routed,
943 * or do nothing if loosely routed.
944 * Record interface address and bring up next address
945 * component. If strictly routed make sure next
946 * address is on directly accessible net.
947 */
948 case IPOPT_LSRR:
949 case IPOPT_SSRR: {
950 struct psref psref;
951 if (ip_allowsrcrt == 0) {
952 type = ICMP_UNREACH;
953 code = ICMP_UNREACH_NET_PROHIB;
954 goto bad;
955 }
956 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
957 code = &cp[IPOPT_OLEN] - (u_char *)ip;
958 goto bad;
959 }
960 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
961 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
962 goto bad;
963 }
964 ipaddr.sin_addr = ip->ip_dst;
965
966 s = pserialize_read_enter();
967 ifa = ifa_ifwithaddr(sintosa(&ipaddr));
968 if (ifa == NULL) {
969 pserialize_read_exit(s);
970 if (opt == IPOPT_SSRR) {
971 type = ICMP_UNREACH;
972 code = ICMP_UNREACH_SRCFAIL;
973 goto bad;
974 }
975 /*
976 * Loose routing, and not at next destination
977 * yet; nothing to do except forward.
978 */
979 break;
980 }
981 pserialize_read_exit(s);
982
983 off--; /* 0 origin */
984 if ((off + sizeof(struct in_addr)) > optlen) {
985 /*
986 * End of source route. Should be for us.
987 */
988 save_rte(cp, ip->ip_src);
989 break;
990 }
991 /*
992 * locate outgoing interface
993 */
994 memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off),
995 sizeof(ipaddr.sin_addr));
996 if (opt == IPOPT_SSRR) {
997 ifa = ifa_ifwithladdr_psref(sintosa(&ipaddr),
998 &psref);
999 if (ifa != NULL)
1000 ia = ifatoia(ifa);
1001 else
1002 ia = NULL;
1003 } else {
1004 ia = ip_rtaddr(ipaddr.sin_addr, &psref);
1005 }
1006 if (ia == NULL) {
1007 type = ICMP_UNREACH;
1008 code = ICMP_UNREACH_SRCFAIL;
1009 goto bad;
1010 }
1011 ip->ip_dst = ipaddr.sin_addr;
1012 bcopy((void *)&ia->ia_addr.sin_addr,
1013 (void *)(cp + off), sizeof(struct in_addr));
1014 ia4_release(ia, &psref);
1015 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1016 /*
1017 * Let ip_intr's mcast routing check handle mcast pkts
1018 */
1019 forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1020 break;
1021 }
1022
1023 case IPOPT_RR: {
1024 struct psref psref;
1025 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1026 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1027 goto bad;
1028 }
1029 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1030 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1031 goto bad;
1032 }
1033 /*
1034 * If no space remains, ignore.
1035 */
1036 off--; /* 0 origin */
1037 if ((off + sizeof(struct in_addr)) > optlen)
1038 break;
1039 memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst),
1040 sizeof(ipaddr.sin_addr));
1041 /*
1042 * locate outgoing interface; if we're the destination,
1043 * use the incoming interface (should be same).
1044 */
1045 ifa = ifa_ifwithaddr_psref(sintosa(&ipaddr), &psref);
1046 if (ifa == NULL) {
1047 ia = ip_rtaddr(ipaddr.sin_addr, &psref);
1048 if (ia == NULL) {
1049 type = ICMP_UNREACH;
1050 code = ICMP_UNREACH_HOST;
1051 goto bad;
1052 }
1053 } else {
1054 ia = ifatoia(ifa);
1055 }
1056 bcopy((void *)&ia->ia_addr.sin_addr,
1057 (void *)(cp + off), sizeof(struct in_addr));
1058 ia4_release(ia, &psref);
1059 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1060 break;
1061 }
1062
1063 case IPOPT_TS:
1064 code = cp - (u_char *)ip;
1065 ipt = (struct ip_timestamp *)cp;
1066 if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
1067 code = (u_char *)&ipt->ipt_len - (u_char *)ip;
1068 goto bad;
1069 }
1070 if (ipt->ipt_ptr < 5) {
1071 code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
1072 goto bad;
1073 }
1074 if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1075 if (++ipt->ipt_oflw == 0) {
1076 code = (u_char *)&ipt->ipt_ptr -
1077 (u_char *)ip;
1078 goto bad;
1079 }
1080 break;
1081 }
1082 cp0 = (cp + ipt->ipt_ptr - 1);
1083 switch (ipt->ipt_flg) {
1084
1085 case IPOPT_TS_TSONLY:
1086 break;
1087
1088 case IPOPT_TS_TSANDADDR: {
1089 struct ifnet *rcvif;
1090 int _s, _ss;
1091
1092 if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1093 sizeof(struct in_addr) > ipt->ipt_len) {
1094 code = (u_char *)&ipt->ipt_ptr -
1095 (u_char *)ip;
1096 goto bad;
1097 }
1098 ipaddr.sin_addr = dst;
1099 _ss = pserialize_read_enter();
1100 rcvif = m_get_rcvif(m, &_s);
1101 if (__predict_true(rcvif != NULL)) {
1102 ifa = ifaof_ifpforaddr(sintosa(&ipaddr),
1103 rcvif);
1104 }
1105 m_put_rcvif(rcvif, &_s);
1106 if (ifa == NULL) {
1107 pserialize_read_exit(_ss);
1108 break;
1109 }
1110 ia = ifatoia(ifa);
1111 bcopy(&ia->ia_addr.sin_addr,
1112 cp0, sizeof(struct in_addr));
1113 pserialize_read_exit(_ss);
1114 ipt->ipt_ptr += sizeof(struct in_addr);
1115 break;
1116 }
1117
1118 case IPOPT_TS_PRESPEC:
1119 if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1120 sizeof(struct in_addr) > ipt->ipt_len) {
1121 code = (u_char *)&ipt->ipt_ptr -
1122 (u_char *)ip;
1123 goto bad;
1124 }
1125 memcpy(&ipaddr.sin_addr, cp0,
1126 sizeof(struct in_addr));
1127 s = pserialize_read_enter();
1128 ifa = ifa_ifwithaddr(sintosa(&ipaddr));
1129 if (ifa == NULL) {
1130 pserialize_read_exit(s);
1131 continue;
1132 }
1133 pserialize_read_exit(s);
1134 ipt->ipt_ptr += sizeof(struct in_addr);
1135 break;
1136
1137 default:
1138 /* XXX can't take &ipt->ipt_flg */
1139 code = (u_char *)&ipt->ipt_ptr -
1140 (u_char *)ip + 1;
1141 goto bad;
1142 }
1143 ntime = iptime();
1144 cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
1145 memmove((char *)cp + ipt->ipt_ptr - 1, cp0,
1146 sizeof(n_time));
1147 ipt->ipt_ptr += sizeof(n_time);
1148 }
1149 }
1150 if (forward) {
1151 struct ifnet *rcvif;
1152 struct psref _psref;
1153
1154 if (ip_forwsrcrt == 0) {
1155 type = ICMP_UNREACH;
1156 code = ICMP_UNREACH_SRCFAIL;
1157 goto bad;
1158 }
1159
1160 rcvif = m_get_rcvif_psref(m, &_psref);
1161 if (__predict_false(rcvif == NULL)) {
1162 type = ICMP_UNREACH;
1163 code = ICMP_UNREACH_HOST;
1164 goto bad;
1165 }
1166 ip_forward(m, 1, rcvif);
1167 m_put_rcvif_psref(rcvif, &_psref);
1168 return true;
1169 }
1170 return false;
1171 bad:
1172 icmp_error(m, type, code, 0, 0);
1173 IP_STATINC(IP_STAT_BADOPTIONS);
1174 return true;
1175 }
1176
1177 /*
1178 * ip_rtaddr: given address of next destination (final or next hop),
1179 * return internet address info of interface to be used to get there.
1180 */
1181 static struct in_ifaddr *
1182 ip_rtaddr(struct in_addr dst, struct psref *psref)
1183 {
1184 struct rtentry *rt;
1185 union {
1186 struct sockaddr dst;
1187 struct sockaddr_in dst4;
1188 } u;
1189 struct route *ro;
1190
1191 sockaddr_in_init(&u.dst4, &dst, 0);
1192
1193 ro = percpu_getref(ipforward_rt_percpu);
1194 rt = rtcache_lookup(ro, &u.dst);
1195 if (rt == NULL) {
1196 percpu_putref(ipforward_rt_percpu);
1197 return NULL;
1198 }
1199
1200 ia4_acquire(ifatoia(rt->rt_ifa), psref);
1201 rtcache_unref(rt, ro);
1202 percpu_putref(ipforward_rt_percpu);
1203
1204 return ifatoia(rt->rt_ifa);
1205 }
1206
1207 /*
1208 * save_rte: save incoming source route for use in replies, to be picked
1209 * up later by ip_srcroute if the receiver is interested.
1210 */
1211 static void
1212 save_rte(u_char *option, struct in_addr dst)
1213 {
1214 unsigned olen;
1215
1216 olen = option[IPOPT_OLEN];
1217 if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
1218 return;
1219 memcpy((void *)ip_srcrt.srcopt, (void *)option, olen);
1220 ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
1221 ip_srcrt.dst = dst;
1222 }
1223
1224 /*
1225 * Retrieve incoming source route for use in replies,
1226 * in the same form used by setsockopt.
1227 * The first hop is placed before the options, will be removed later.
1228 */
1229 struct mbuf *
1230 ip_srcroute(void)
1231 {
1232 struct in_addr *p, *q;
1233 struct mbuf *m;
1234
1235 if (ip_nhops == 0)
1236 return NULL;
1237 m = m_get(M_DONTWAIT, MT_SOOPTS);
1238 if (m == 0)
1239 return NULL;
1240
1241 MCLAIM(m, &inetdomain.dom_mowner);
1242 #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1243
1244 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
1245 m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
1246 OPTSIZ;
1247
1248 /*
1249 * First save first hop for return route
1250 */
1251 p = &ip_srcrt.route[ip_nhops - 1];
1252 *(mtod(m, struct in_addr *)) = *p--;
1253
1254 /*
1255 * Copy option fields and padding (nop) to mbuf.
1256 */
1257 ip_srcrt.nop = IPOPT_NOP;
1258 ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
1259 memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop,
1260 OPTSIZ);
1261 q = (struct in_addr *)(mtod(m, char *) +
1262 sizeof(struct in_addr) + OPTSIZ);
1263 #undef OPTSIZ
1264 /*
1265 * Record return path as an IP source route,
1266 * reversing the path (pointers are now aligned).
1267 */
1268 while (p >= ip_srcrt.route) {
1269 *q++ = *p--;
1270 }
1271 /*
1272 * Last hop goes to final destination.
1273 */
1274 *q = ip_srcrt.dst;
1275 return (m);
1276 }
1277
1278 const int inetctlerrmap[PRC_NCMDS] = {
1279 [PRC_MSGSIZE] = EMSGSIZE,
1280 [PRC_HOSTDEAD] = EHOSTDOWN,
1281 [PRC_HOSTUNREACH] = EHOSTUNREACH,
1282 [PRC_UNREACH_NET] = EHOSTUNREACH,
1283 [PRC_UNREACH_HOST] = EHOSTUNREACH,
1284 [PRC_UNREACH_PROTOCOL] = ECONNREFUSED,
1285 [PRC_UNREACH_PORT] = ECONNREFUSED,
1286 [PRC_UNREACH_SRCFAIL] = EHOSTUNREACH,
1287 [PRC_PARAMPROB] = ENOPROTOOPT,
1288 };
1289
1290 void
1291 ip_fasttimo(void)
1292 {
1293 if (ip_drainwanted) {
1294 ip_drain();
1295 ip_drainwanted = 0;
1296 }
1297 }
1298
1299 void
1300 ip_drainstub(void)
1301 {
1302 ip_drainwanted = 1;
1303 }
1304
1305 /*
1306 * Forward a packet. If some error occurs return the sender
1307 * an icmp packet. Note we can't always generate a meaningful
1308 * icmp message because icmp doesn't have a large enough repertoire
1309 * of codes and types.
1310 *
1311 * If not forwarding, just drop the packet. This could be confusing
1312 * if ipforwarding was zero but some routing protocol was advancing
1313 * us as a gateway to somewhere. However, we must let the routing
1314 * protocol deal with that.
1315 *
1316 * The srcrt parameter indicates whether the packet is being forwarded
1317 * via a source route.
1318 */
1319 static void
1320 ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif)
1321 {
1322 struct ip *ip = mtod(m, struct ip *);
1323 struct rtentry *rt;
1324 int error, type = 0, code = 0, destmtu = 0;
1325 struct mbuf *mcopy;
1326 n_long dest;
1327 union {
1328 struct sockaddr dst;
1329 struct sockaddr_in dst4;
1330 } u;
1331 uint64_t *ips;
1332 struct route *ro;
1333
1334 KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software "
1335 "interrupt handler; synchronization assumptions violated");
1336
1337 /*
1338 * We are now in the output path.
1339 */
1340 MCLAIM(m, &ip_tx_mowner);
1341
1342 /*
1343 * Clear any in-bound checksum flags for this packet.
1344 */
1345 m->m_pkthdr.csum_flags = 0;
1346
1347 dest = 0;
1348 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1349 IP_STATINC(IP_STAT_CANTFORWARD);
1350 m_freem(m);
1351 return;
1352 }
1353
1354 if (ip->ip_ttl <= IPTTLDEC) {
1355 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1356 return;
1357 }
1358
1359 sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
1360
1361 ro = percpu_getref(ipforward_rt_percpu);
1362 rt = rtcache_lookup(ro, &u.dst);
1363 if (rt == NULL) {
1364 percpu_putref(ipforward_rt_percpu);
1365 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0);
1366 return;
1367 }
1368
1369 /*
1370 * Save at most 68 bytes of the packet in case
1371 * we need to generate an ICMP message to the src.
1372 * Pullup to avoid sharing mbuf cluster between m and mcopy.
1373 */
1374 mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
1375 if (mcopy)
1376 mcopy = m_pullup(mcopy, ip->ip_hl << 2);
1377
1378 ip->ip_ttl -= IPTTLDEC;
1379
1380 /*
1381 * If forwarding packet using same interface that it came in on,
1382 * perhaps should send a redirect to sender to shortcut a hop.
1383 * Only send redirect if source is sending directly to us,
1384 * and if packet was not source routed (or has any options).
1385 * Also, don't send redirect if forwarding using a default route
1386 * or a route modified by a redirect.
1387 */
1388 if (rt->rt_ifp == rcvif &&
1389 (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1390 !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) &&
1391 ipsendredirects && !srcrt) {
1392 if (rt->rt_ifa &&
1393 (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
1394 ifatoia(rt->rt_ifa)->ia_subnet) {
1395 if (rt->rt_flags & RTF_GATEWAY)
1396 dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1397 else
1398 dest = ip->ip_dst.s_addr;
1399 /*
1400 * Router requirements says to only send host
1401 * redirects.
1402 */
1403 type = ICMP_REDIRECT;
1404 code = ICMP_REDIRECT_HOST;
1405 }
1406 }
1407 rtcache_unref(rt, ro);
1408
1409 error = ip_output(m, NULL, ro,
1410 (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
1411 NULL, NULL);
1412
1413 if (error) {
1414 IP_STATINC(IP_STAT_CANTFORWARD);
1415 goto error;
1416 }
1417
1418 ips = IP_STAT_GETREF();
1419 ips[IP_STAT_FORWARD]++;
1420
1421 if (type) {
1422 ips[IP_STAT_REDIRECTSENT]++;
1423 IP_STAT_PUTREF();
1424 goto redirect;
1425 }
1426
1427 IP_STAT_PUTREF();
1428 if (mcopy) {
1429 #ifdef GATEWAY
1430 if (mcopy->m_flags & M_CANFASTFWD)
1431 ipflow_create(ro, mcopy);
1432 #endif
1433 m_freem(mcopy);
1434 }
1435
1436 percpu_putref(ipforward_rt_percpu);
1437 return;
1438
1439 redirect:
1440 error:
1441 if (mcopy == NULL) {
1442 percpu_putref(ipforward_rt_percpu);
1443 return;
1444 }
1445
1446 switch (error) {
1447
1448 case 0: /* forwarded, but need redirect */
1449 /* type, code set above */
1450 break;
1451
1452 case ENETUNREACH: /* shouldn't happen, checked above */
1453 case EHOSTUNREACH:
1454 case ENETDOWN:
1455 case EHOSTDOWN:
1456 default:
1457 type = ICMP_UNREACH;
1458 code = ICMP_UNREACH_HOST;
1459 break;
1460
1461 case EMSGSIZE:
1462 type = ICMP_UNREACH;
1463 code = ICMP_UNREACH_NEEDFRAG;
1464
1465 if ((rt = rtcache_validate(ro)) != NULL) {
1466 destmtu = rt->rt_ifp->if_mtu;
1467 rtcache_unref(rt, ro);
1468 }
1469 #ifdef IPSEC
1470 if (ipsec_used)
1471 (void)ipsec4_forward(mcopy, &destmtu);
1472 #endif
1473 IP_STATINC(IP_STAT_CANTFRAG);
1474 break;
1475
1476 case ENOBUFS:
1477 /*
1478 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812,
1479 * Requirements for IP Version 4 Routers. Source quench can
1480 * big problem under DoS attacks or if the underlying
1481 * interface is rate-limited.
1482 */
1483 if (mcopy)
1484 m_freem(mcopy);
1485 percpu_putref(ipforward_rt_percpu);
1486 return;
1487 }
1488 icmp_error(mcopy, type, code, dest, destmtu);
1489 percpu_putref(ipforward_rt_percpu);
1490 }
1491
1492 void
1493 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1494 struct mbuf *m)
1495 {
1496 struct socket *so = inp->inp_socket;
1497 ifnet_t *ifp;
1498 int inpflags = inp->inp_flags;
1499 struct psref psref;
1500
1501 ifp = m_get_rcvif_psref(m, &psref);
1502 if (__predict_false(ifp == NULL))
1503 return; /* XXX should report error? */
1504
1505 if (so->so_options & SO_TIMESTAMP
1506 #ifdef SO_OTIMESTAMP
1507 || so->so_options & SO_OTIMESTAMP
1508 #endif
1509 ) {
1510 struct timeval tv;
1511
1512 microtime(&tv);
1513 #ifdef SO_OTIMESTAMP
1514 if (so->so_options & SO_OTIMESTAMP) {
1515 struct timeval50 tv50;
1516 timeval_to_timeval50(&tv, &tv50);
1517 *mp = sbcreatecontrol((void *) &tv50, sizeof(tv50),
1518 SCM_OTIMESTAMP, SOL_SOCKET);
1519 } else
1520 #endif
1521 *mp = sbcreatecontrol((void *) &tv, sizeof(tv),
1522 SCM_TIMESTAMP, SOL_SOCKET);
1523 if (*mp)
1524 mp = &(*mp)->m_next;
1525 }
1526 if (inpflags & INP_RECVDSTADDR) {
1527 *mp = sbcreatecontrol((void *) &ip->ip_dst,
1528 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1529 if (*mp)
1530 mp = &(*mp)->m_next;
1531 }
1532 if (inpflags & INP_RECVPKTINFO) {
1533 struct in_pktinfo ipi;
1534 ipi.ipi_addr = ip->ip_src;
1535 ipi.ipi_ifindex = ifp->if_index;
1536 *mp = sbcreatecontrol((void *) &ipi,
1537 sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP);
1538 if (*mp)
1539 mp = &(*mp)->m_next;
1540 }
1541 if (inpflags & INP_PKTINFO) {
1542 struct in_pktinfo ipi;
1543 ipi.ipi_addr = ip->ip_dst;
1544 ipi.ipi_ifindex = ifp->if_index;
1545 *mp = sbcreatecontrol((void *) &ipi,
1546 sizeof(ipi), IP_PKTINFO, IPPROTO_IP);
1547 if (*mp)
1548 mp = &(*mp)->m_next;
1549 }
1550 if (inpflags & INP_RECVIF) {
1551 struct sockaddr_dl sdl;
1552
1553 sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0,
1554 NULL, 0);
1555 *mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP);
1556 if (*mp)
1557 mp = &(*mp)->m_next;
1558 }
1559 if (inpflags & INP_RECVTTL) {
1560 *mp = sbcreatecontrol((void *) &ip->ip_ttl,
1561 sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP);
1562 if (*mp)
1563 mp = &(*mp)->m_next;
1564 }
1565 m_put_rcvif_psref(ifp, &psref);
1566 }
1567
1568 /*
1569 * sysctl helper routine for net.inet.ip.forwsrcrt.
1570 */
1571 static int
1572 sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS)
1573 {
1574 int error, tmp;
1575 struct sysctlnode node;
1576
1577 node = *rnode;
1578 tmp = ip_forwsrcrt;
1579 node.sysctl_data = &tmp;
1580 error = sysctl_lookup(SYSCTLFN_CALL(&node));
1581 if (error || newp == NULL)
1582 return (error);
1583
1584 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT,
1585 0, NULL, NULL, NULL);
1586 if (error)
1587 return (error);
1588
1589 ip_forwsrcrt = tmp;
1590
1591 return (0);
1592 }
1593
1594 /*
1595 * sysctl helper routine for net.inet.ip.mtudisctimeout. checks the
1596 * range of the new value and tweaks timers if it changes.
1597 */
1598 static int
1599 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS)
1600 {
1601 int error, tmp;
1602 struct sysctlnode node;
1603
1604 node = *rnode;
1605 tmp = ip_mtudisc_timeout;
1606 node.sysctl_data = &tmp;
1607 error = sysctl_lookup(SYSCTLFN_CALL(&node));
1608 if (error || newp == NULL)
1609 return (error);
1610 if (tmp < 0)
1611 return (EINVAL);
1612
1613 /* XXX NOMPSAFE still need softnet_lock */
1614 mutex_enter(softnet_lock);
1615
1616 ip_mtudisc_timeout = tmp;
1617 rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout);
1618
1619 mutex_exit(softnet_lock);
1620
1621 return (0);
1622 }
1623
1624 static int
1625 sysctl_net_inet_ip_stats(SYSCTLFN_ARGS)
1626 {
1627
1628 return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS));
1629 }
1630
1631 static void
1632 sysctl_net_inet_ip_setup(struct sysctllog **clog)
1633 {
1634 sysctl_createv(clog, 0, NULL, NULL,
1635 CTLFLAG_PERMANENT,
1636 CTLTYPE_NODE, "inet",
1637 SYSCTL_DESCR("PF_INET related settings"),
1638 NULL, 0, NULL, 0,
1639 CTL_NET, PF_INET, CTL_EOL);
1640 sysctl_createv(clog, 0, NULL, NULL,
1641 CTLFLAG_PERMANENT,
1642 CTLTYPE_NODE, "ip",
1643 SYSCTL_DESCR("IPv4 related settings"),
1644 NULL, 0, NULL, 0,
1645 CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL);
1646
1647 sysctl_createv(clog, 0, NULL, NULL,
1648 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1649 CTLTYPE_INT, "forwarding",
1650 SYSCTL_DESCR("Enable forwarding of INET datagrams"),
1651 NULL, 0, &ipforwarding, 0,
1652 CTL_NET, PF_INET, IPPROTO_IP,
1653 IPCTL_FORWARDING, CTL_EOL);
1654 sysctl_createv(clog, 0, NULL, NULL,
1655 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1656 CTLTYPE_INT, "redirect",
1657 SYSCTL_DESCR("Enable sending of ICMP redirect messages"),
1658 NULL, 0, &ipsendredirects, 0,
1659 CTL_NET, PF_INET, IPPROTO_IP,
1660 IPCTL_SENDREDIRECTS, CTL_EOL);
1661 sysctl_createv(clog, 0, NULL, NULL,
1662 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1663 CTLTYPE_INT, "ttl",
1664 SYSCTL_DESCR("Default TTL for an INET datagram"),
1665 NULL, 0, &ip_defttl, 0,
1666 CTL_NET, PF_INET, IPPROTO_IP,
1667 IPCTL_DEFTTL, CTL_EOL);
1668 #ifdef IPCTL_DEFMTU
1669 sysctl_createv(clog, 0, NULL, NULL,
1670 CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */,
1671 CTLTYPE_INT, "mtu",
1672 SYSCTL_DESCR("Default MTA for an INET route"),
1673 NULL, 0, &ip_mtu, 0,
1674 CTL_NET, PF_INET, IPPROTO_IP,
1675 IPCTL_DEFMTU, CTL_EOL);
1676 #endif /* IPCTL_DEFMTU */
1677 sysctl_createv(clog, 0, NULL, NULL,
1678 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1679 CTLTYPE_INT, "forwsrcrt",
1680 SYSCTL_DESCR("Enable forwarding of source-routed "
1681 "datagrams"),
1682 sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0,
1683 CTL_NET, PF_INET, IPPROTO_IP,
1684 IPCTL_FORWSRCRT, CTL_EOL);
1685 sysctl_createv(clog, 0, NULL, NULL,
1686 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1687 CTLTYPE_INT, "directed-broadcast",
1688 SYSCTL_DESCR("Enable forwarding of broadcast datagrams"),
1689 NULL, 0, &ip_directedbcast, 0,
1690 CTL_NET, PF_INET, IPPROTO_IP,
1691 IPCTL_DIRECTEDBCAST, CTL_EOL);
1692 sysctl_createv(clog, 0, NULL, NULL,
1693 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1694 CTLTYPE_INT, "allowsrcrt",
1695 SYSCTL_DESCR("Accept source-routed datagrams"),
1696 NULL, 0, &ip_allowsrcrt, 0,
1697 CTL_NET, PF_INET, IPPROTO_IP,
1698 IPCTL_ALLOWSRCRT, CTL_EOL);
1699
1700 sysctl_createv(clog, 0, NULL, NULL,
1701 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1702 CTLTYPE_INT, "mtudisc",
1703 SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"),
1704 NULL, 0, &ip_mtudisc, 0,
1705 CTL_NET, PF_INET, IPPROTO_IP,
1706 IPCTL_MTUDISC, CTL_EOL);
1707 sysctl_createv(clog, 0, NULL, NULL,
1708 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1709 CTLTYPE_INT, "anonportmin",
1710 SYSCTL_DESCR("Lowest ephemeral port number to assign"),
1711 sysctl_net_inet_ip_ports, 0, &anonportmin, 0,
1712 CTL_NET, PF_INET, IPPROTO_IP,
1713 IPCTL_ANONPORTMIN, CTL_EOL);
1714 sysctl_createv(clog, 0, NULL, NULL,
1715 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1716 CTLTYPE_INT, "anonportmax",
1717 SYSCTL_DESCR("Highest ephemeral port number to assign"),
1718 sysctl_net_inet_ip_ports, 0, &anonportmax, 0,
1719 CTL_NET, PF_INET, IPPROTO_IP,
1720 IPCTL_ANONPORTMAX, CTL_EOL);
1721 sysctl_createv(clog, 0, NULL, NULL,
1722 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1723 CTLTYPE_INT, "mtudisctimeout",
1724 SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"),
1725 sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0,
1726 CTL_NET, PF_INET, IPPROTO_IP,
1727 IPCTL_MTUDISCTIMEOUT, CTL_EOL);
1728 #ifndef IPNOPRIVPORTS
1729 sysctl_createv(clog, 0, NULL, NULL,
1730 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1731 CTLTYPE_INT, "lowportmin",
1732 SYSCTL_DESCR("Lowest privileged ephemeral port number "
1733 "to assign"),
1734 sysctl_net_inet_ip_ports, 0, &lowportmin, 0,
1735 CTL_NET, PF_INET, IPPROTO_IP,
1736 IPCTL_LOWPORTMIN, CTL_EOL);
1737 sysctl_createv(clog, 0, NULL, NULL,
1738 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1739 CTLTYPE_INT, "lowportmax",
1740 SYSCTL_DESCR("Highest privileged ephemeral port number "
1741 "to assign"),
1742 sysctl_net_inet_ip_ports, 0, &lowportmax, 0,
1743 CTL_NET, PF_INET, IPPROTO_IP,
1744 IPCTL_LOWPORTMAX, CTL_EOL);
1745 #endif /* IPNOPRIVPORTS */
1746 #if NGRE > 0
1747 sysctl_createv(clog, 0, NULL, NULL,
1748 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1749 CTLTYPE_INT, "grettl",
1750 SYSCTL_DESCR("Default TTL for a gre tunnel datagram"),
1751 NULL, 0, &ip_gre_ttl, 0,
1752 CTL_NET, PF_INET, IPPROTO_IP,
1753 IPCTL_GRE_TTL, CTL_EOL);
1754 #endif /* NGRE */
1755 sysctl_createv(clog, 0, NULL, NULL,
1756 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1757 CTLTYPE_INT, "checkinterface",
1758 SYSCTL_DESCR("Enable receive side of Strong ES model "
1759 "from RFC1122"),
1760 NULL, 0, &ip_checkinterface, 0,
1761 CTL_NET, PF_INET, IPPROTO_IP,
1762 IPCTL_CHECKINTERFACE, CTL_EOL);
1763 sysctl_createv(clog, 0, NULL, NULL,
1764 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1765 CTLTYPE_INT, "random_id",
1766 SYSCTL_DESCR("Assign random ip_id values"),
1767 NULL, 0, &ip_do_randomid, 0,
1768 CTL_NET, PF_INET, IPPROTO_IP,
1769 IPCTL_RANDOMID, CTL_EOL);
1770 sysctl_createv(clog, 0, NULL, NULL,
1771 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1772 CTLTYPE_INT, "do_loopback_cksum",
1773 SYSCTL_DESCR("Perform IP checksum on loopback"),
1774 NULL, 0, &ip_do_loopback_cksum, 0,
1775 CTL_NET, PF_INET, IPPROTO_IP,
1776 IPCTL_LOOPBACKCKSUM, CTL_EOL);
1777 sysctl_createv(clog, 0, NULL, NULL,
1778 CTLFLAG_PERMANENT,
1779 CTLTYPE_STRUCT, "stats",
1780 SYSCTL_DESCR("IP statistics"),
1781 sysctl_net_inet_ip_stats, 0, NULL, 0,
1782 CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS,
1783 CTL_EOL);
1784 #if NARP
1785 sysctl_createv(clog, 0, NULL, NULL,
1786 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1787 CTLTYPE_INT, "dad_count",
1788 SYSCTL_DESCR("Number of Duplicate Address Detection "
1789 "probes to send"),
1790 NULL, 0, &ip_dad_count, 0,
1791 CTL_NET, PF_INET, IPPROTO_IP,
1792 IPCTL_DAD_COUNT, CTL_EOL);
1793 #endif
1794
1795 /* anonportalgo RFC6056 subtree */
1796 const struct sysctlnode *portalgo_node;
1797 sysctl_createv(clog, 0, NULL, &portalgo_node,
1798 CTLFLAG_PERMANENT,
1799 CTLTYPE_NODE, "anonportalgo",
1800 SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"),
1801 NULL, 0, NULL, 0,
1802 CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL);
1803 sysctl_createv(clog, 0, &portalgo_node, NULL,
1804 CTLFLAG_PERMANENT,
1805 CTLTYPE_STRING, "available",
1806 SYSCTL_DESCR("available algorithms"),
1807 sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN,
1808 CTL_CREATE, CTL_EOL);
1809 sysctl_createv(clog, 0, &portalgo_node, NULL,
1810 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1811 CTLTYPE_STRING, "selected",
1812 SYSCTL_DESCR("selected algorithm"),
1813 sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN,
1814 CTL_CREATE, CTL_EOL);
1815 sysctl_createv(clog, 0, &portalgo_node, NULL,
1816 CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1817 CTLTYPE_STRUCT, "reserve",
1818 SYSCTL_DESCR("bitmap of reserved ports"),
1819 sysctl_portalgo_reserve4, 0, NULL, 0,
1820 CTL_CREATE, CTL_EOL);
1821 }
1822
1823 void
1824 ip_statinc(u_int stat)
1825 {
1826
1827 KASSERT(stat < IP_NSTATS);
1828 IP_STATINC(stat);
1829 }
1830