220SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
221 &VNET_NAME(ipstealth), 0,
222 "IP stealth mode, no TTL decrementation on forwarding");
223#endif
224
225#ifdef FLOWTABLE
226static VNET_DEFINE(int, ip_output_flowtable_size) = 2048;
227VNET_DEFINE(struct flowtable *, ip_ft);
228#define V_ip_output_flowtable_size VNET(ip_output_flowtable_size)
229
230SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN,
231 &VNET_NAME(ip_output_flowtable_size), 2048,
232 "number of entries in the per-cpu output flow caches");
233#endif
234
235VNET_DEFINE(int, fw_one_pass) = 1;
236
237static void ip_freef(struct ipqhead *, struct ipq *);
238
239/*
240 * Kernel module interface for updating ipstat. The argument is an index
241 * into ipstat treated as an array of u_long. While this encodes the general
242 * layout of ipstat into the caller, it doesn't encode its location, so that
243 * future changes to add, for example, per-CPU stats support won't cause
244 * binary compatibility problems for kernel modules.
245 */
246void
247kmod_ipstat_inc(int statnum)
248{
249
250 (*((u_long *)&V_ipstat + statnum))++;
251}
252
253void
254kmod_ipstat_dec(int statnum)
255{
256
257 (*((u_long *)&V_ipstat + statnum))--;
258}
259
260static int
261sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
262{
263 int error, qlimit;
264
265 netisr_getqlimit(&ip_nh, &qlimit);
266 error = sysctl_handle_int(oidp, &qlimit, 0, req);
267 if (error || !req->newptr)
268 return (error);
269 if (qlimit < 1)
270 return (EINVAL);
271 return (netisr_setqlimit(&ip_nh, qlimit));
272}
273SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
274 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I",
275 "Maximum size of the IP input queue");
276
277static int
278sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
279{
280 u_int64_t qdrops_long;
281 int error, qdrops;
282
283 netisr_getqdrops(&ip_nh, &qdrops_long);
284 qdrops = qdrops_long;
285 error = sysctl_handle_int(oidp, &qdrops, 0, req);
286 if (error || !req->newptr)
287 return (error);
288 if (qdrops != 0)
289 return (EINVAL);
290 netisr_clearqdrops(&ip_nh);
291 return (0);
292}
293
294SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
295 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I",
296 "Number of packets dropped from the IP input queue");
297
298/*
299 * IP initialization: fill in IP protocol switch table.
300 * All protocols not implemented in kernel go to raw IP protocol handler.
301 */
302void
303ip_init(void)
304{
305 struct protosw *pr;
306 int i;
307
308 V_ip_id = time_second & 0xffff;
309
310 TAILQ_INIT(&V_in_ifaddrhead);
311 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
312
313 /* Initialize IP reassembly queue. */
314 for (i = 0; i < IPREASS_NHASH; i++)
315 TAILQ_INIT(&V_ipq[i]);
316 V_maxnipq = nmbclusters / 32;
317 V_maxfragsperpacket = 16;
318 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
319 NULL, UMA_ALIGN_PTR, 0);
320 maxnipq_update();
321
322 /* Initialize packet filter hooks. */
323 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF;
324 V_inet_pfil_hook.ph_af = AF_INET;
325 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0)
326 printf("%s: WARNING: unable to register pfil hook, "
327 "error %d\n", __func__, i);
328
329#ifdef FLOWTABLE
330 if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size",
331 &V_ip_output_flowtable_size)) {
332 if (V_ip_output_flowtable_size < 256)
333 V_ip_output_flowtable_size = 256;
334 if (!powerof2(V_ip_output_flowtable_size)) {
335 printf("flowtable must be power of 2 size\n");
336 V_ip_output_flowtable_size = 2048;
337 }
338 } else {
339 /*
340 * round up to the next power of 2
341 */
342 V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1);
343 }
344 V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU);
345#endif
346
347 /* Skip initialization of globals for non-default instances. */
348 if (!IS_DEFAULT_VNET(curvnet))
349 return;
350
351 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
352 if (pr == NULL)
353 panic("ip_init: PF_INET not found");
354
355 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
356 for (i = 0; i < IPPROTO_MAX; i++)
357 ip_protox[i] = pr - inetsw;
358 /*
359 * Cycle through IP protocols and put them into the appropriate place
360 * in ip_protox[].
361 */
362 for (pr = inetdomain.dom_protosw;
363 pr < inetdomain.dom_protoswNPROTOSW; pr++)
364 if (pr->pr_domain->dom_family == PF_INET &&
365 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
366 /* Be careful to only index valid IP protocols. */
367 if (pr->pr_protocol < IPPROTO_MAX)
368 ip_protox[pr->pr_protocol] = pr - inetsw;
369 }
370
371 /* Start ipport_tick. */
372 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE);
373 callout_reset(&ipport_tick_callout, 1, ipport_tick, NULL);
374 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL,
375 SHUTDOWN_PRI_DEFAULT);
376 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change,
377 NULL, EVENTHANDLER_PRI_ANY);
378
379 /* Initialize various other remaining things. */
380 IPQ_LOCK_INIT();
381 netisr_register(&ip_nh);
382}
383
384#ifdef VIMAGE
385void
386ip_destroy(void)
387{
388
389 /* Cleanup in_ifaddr hash table; should be empty. */
390 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
391
392 IPQ_LOCK();
393 ip_drain_locked();
394 IPQ_UNLOCK();
395
396 uma_zdestroy(V_ipq_zone);
397}
398#endif
399
400void
401ip_fini(void *xtp)
402{
403
404 callout_stop(&ipport_tick_callout);
405}
406
407/*
408 * Ip input routine. Checksum and byte swap header. If fragmented
409 * try to reassemble. Process options. Pass to next level.
410 */
411void
412ip_input(struct mbuf *m)
413{
414 struct ip *ip = NULL;
415 struct in_ifaddr *ia = NULL;
416 struct ifaddr *ifa;
417 struct ifnet *ifp;
418 int checkif, hlen = 0;
419 u_short sum;
420 int dchg = 0; /* dest changed after fw */
421 struct in_addr odst; /* original dst address */
422
423 M_ASSERTPKTHDR(m);
424
425 if (m->m_flags & M_FASTFWD_OURS) {
426 /*
427 * Firewall or NAT changed destination to local.
428 * We expect ip_len and ip_off to be in host byte order.
429 */
430 m->m_flags &= ~M_FASTFWD_OURS;
431 /* Set up some basics that will be used later. */
432 ip = mtod(m, struct ip *);
433 hlen = ip->ip_hl << 2;
434 goto ours;
435 }
436
437 IPSTAT_INC(ips_total);
438
439 if (m->m_pkthdr.len < sizeof(struct ip))
440 goto tooshort;
441
442 if (m->m_len < sizeof (struct ip) &&
443 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
444 IPSTAT_INC(ips_toosmall);
445 return;
446 }
447 ip = mtod(m, struct ip *);
448
449 if (ip->ip_v != IPVERSION) {
450 IPSTAT_INC(ips_badvers);
451 goto bad;
452 }
453
454 hlen = ip->ip_hl << 2;
455 if (hlen < sizeof(struct ip)) { /* minimum header length */
456 IPSTAT_INC(ips_badhlen);
457 goto bad;
458 }
459 if (hlen > m->m_len) {
460 if ((m = m_pullup(m, hlen)) == NULL) {
461 IPSTAT_INC(ips_badhlen);
462 return;
463 }
464 ip = mtod(m, struct ip *);
465 }
466
467 /* 127/8 must not appear on wire - RFC1122 */
468 ifp = m->m_pkthdr.rcvif;
469 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
470 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
471 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
472 IPSTAT_INC(ips_badaddr);
473 goto bad;
474 }
475 }
476
477 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
478 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
479 } else {
480 if (hlen == sizeof(struct ip)) {
481 sum = in_cksum_hdr(ip);
482 } else {
483 sum = in_cksum(m, hlen);
484 }
485 }
486 if (sum) {
487 IPSTAT_INC(ips_badsum);
488 goto bad;
489 }
490
491#ifdef ALTQ
492 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
493 /* packet is dropped by traffic conditioner */
494 return;
495#endif
496
497 /*
498 * Convert fields to host representation.
499 */
500 ip->ip_len = ntohs(ip->ip_len);
501 if (ip->ip_len < hlen) {
502 IPSTAT_INC(ips_badlen);
503 goto bad;
504 }
505 ip->ip_off = ntohs(ip->ip_off);
506
507 /*
508 * Check that the amount of data in the buffers
509 * is as at least much as the IP header would have us expect.
510 * Trim mbufs if longer than we expect.
511 * Drop packet if shorter than we expect.
512 */
513 if (m->m_pkthdr.len < ip->ip_len) {
514tooshort:
515 IPSTAT_INC(ips_tooshort);
516 goto bad;
517 }
518 if (m->m_pkthdr.len > ip->ip_len) {
519 if (m->m_len == m->m_pkthdr.len) {
520 m->m_len = ip->ip_len;
521 m->m_pkthdr.len = ip->ip_len;
522 } else
523 m_adj(m, ip->ip_len - m->m_pkthdr.len);
524 }
525#ifdef IPSEC
526 /*
527 * Bypass packet filtering for packets from a tunnel (gif).
528 */
529 if (ip_ipsec_filtertunnel(m))
530 goto passin;
531#endif /* IPSEC */
532
533 /*
534 * Run through list of hooks for input packets.
535 *
536 * NB: Beware of the destination address changing (e.g.
537 * by NAT rewriting). When this happens, tell
538 * ip_forward to do the right thing.
539 */
540
541 /* Jump over all PFIL processing if hooks are not active. */
542 if (!PFIL_HOOKED(&V_inet_pfil_hook))
543 goto passin;
544
545 odst = ip->ip_dst;
546 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0)
547 return;
548 if (m == NULL) /* consumed by filter */
549 return;
550
551 ip = mtod(m, struct ip *);
552 dchg = (odst.s_addr != ip->ip_dst.s_addr);
553 ifp = m->m_pkthdr.rcvif;
554
555#ifdef IPFIREWALL_FORWARD
556 if (m->m_flags & M_FASTFWD_OURS) {
557 m->m_flags &= ~M_FASTFWD_OURS;
558 goto ours;
559 }
560 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) {
561 /*
562 * Directly ship the packet on. This allows forwarding
563 * packets originally destined to us to some other directly
564 * connected host.
565 */
566 ip_forward(m, dchg);
567 return;
568 }
569#endif /* IPFIREWALL_FORWARD */
570
571passin:
572 /*
573 * Process options and, if not destined for us,
574 * ship it on. ip_dooptions returns 1 when an
575 * error was detected (causing an icmp message
576 * to be sent and the original packet to be freed).
577 */
578 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
579 return;
580
581 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
582 * matter if it is destined to another node, or whether it is
583 * a multicast one, RSVP wants it! and prevents it from being forwarded
584 * anywhere else. Also checks if the rsvp daemon is running before
585 * grabbing the packet.
586 */
587 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP)
588 goto ours;
589
590 /*
591 * Check our list of addresses, to see if the packet is for us.
592 * If we don't have any addresses, assume any unicast packet
593 * we receive might be for us (and let the upper layers deal
594 * with it).
595 */
596 if (TAILQ_EMPTY(&V_in_ifaddrhead) &&
597 (m->m_flags & (M_MCAST|M_BCAST)) == 0)
598 goto ours;
599
600 /*
601 * Enable a consistency check between the destination address
602 * and the arrival interface for a unicast packet (the RFC 1122
603 * strong ES model) if IP forwarding is disabled and the packet
604 * is not locally generated and the packet is not subject to
605 * 'ipfw fwd'.
606 *
607 * XXX - Checking also should be disabled if the destination
608 * address is ipnat'ed to a different interface.
609 *
610 * XXX - Checking is incompatible with IP aliases added
611 * to the loopback interface instead of the interface where
612 * the packets are received.
613 *
614 * XXX - This is the case for carp vhost IPs as well so we
615 * insert a workaround. If the packet got here, we already
616 * checked with carp_iamatch() and carp_forus().
617 */
618 checkif = V_ip_checkinterface && (V_ipforwarding == 0) &&
619 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
620#ifdef DEV_CARP
621 !ifp->if_carp &&
622#endif
623 (dchg == 0);
624
625 /*
626 * Check for exact addresses in the hash bucket.
627 */
628 /* IN_IFADDR_RLOCK(); */
629 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
630 /*
631 * If the address matches, verify that the packet
632 * arrived via the correct interface if checking is
633 * enabled.
634 */
635 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
636 (!checkif || ia->ia_ifp == ifp)) {
637 ifa_ref(&ia->ia_ifa);
638 /* IN_IFADDR_RUNLOCK(); */
639 goto ours;
640 }
641 }
642 /* IN_IFADDR_RUNLOCK(); */
643
644 /*
645 * Check for broadcast addresses.
646 *
647 * Only accept broadcast packets that arrive via the matching
648 * interface. Reception of forwarded directed broadcasts would
649 * be handled via ip_forward() and ether_output() with the loopback
650 * into the stack for SIMPLEX interfaces handled by ether_output().
651 */
652 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
653 IF_ADDR_LOCK(ifp);
654 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
655 if (ifa->ifa_addr->sa_family != AF_INET)
656 continue;
657 ia = ifatoia(ifa);
658 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
659 ip->ip_dst.s_addr) {
660 ifa_ref(ifa);
661 IF_ADDR_UNLOCK(ifp);
662 goto ours;
663 }
664 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) {
665 ifa_ref(ifa);
666 IF_ADDR_UNLOCK(ifp);
667 goto ours;
668 }
669#ifdef BOOTP_COMPAT
670 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
671 ifa_ref(ifa);
672 IF_ADDR_UNLOCK(ifp);
673 goto ours;
674 }
675#endif
676 }
677 IF_ADDR_UNLOCK(ifp);
678 ia = NULL;
679 }
680 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */
681 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
682 IPSTAT_INC(ips_cantforward);
683 m_freem(m);
684 return;
685 }
686 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
687 if (V_ip_mrouter) {
688 /*
689 * If we are acting as a multicast router, all
690 * incoming multicast packets are passed to the
691 * kernel-level multicast forwarding function.
692 * The packet is returned (relatively) intact; if
693 * ip_mforward() returns a non-zero value, the packet
694 * must be discarded, else it may be accepted below.
695 */
696 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
697 IPSTAT_INC(ips_cantforward);
698 m_freem(m);
699 return;
700 }
701
702 /*
703 * The process-level routing daemon needs to receive
704 * all multicast IGMP packets, whether or not this
705 * host belongs to their destination groups.
706 */
707 if (ip->ip_p == IPPROTO_IGMP)
708 goto ours;
709 IPSTAT_INC(ips_forward);
710 }
711 /*
712 * Assume the packet is for us, to avoid prematurely taking
713 * a lock on the in_multi hash. Protocols must perform
714 * their own filtering and update statistics accordingly.
715 */
716 goto ours;
717 }
718 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
719 goto ours;
720 if (ip->ip_dst.s_addr == INADDR_ANY)
721 goto ours;
722
723 /*
724 * FAITH(Firewall Aided Internet Translator)
725 */
726 if (ifp && ifp->if_type == IFT_FAITH) {
727 if (V_ip_keepfaith) {
728 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
729 goto ours;
730 }
731 m_freem(m);
732 return;
733 }
734
735 /*
736 * Not for us; forward if possible and desirable.
737 */
738 if (V_ipforwarding == 0) {
739 IPSTAT_INC(ips_cantforward);
740 m_freem(m);
741 } else {
742#ifdef IPSEC
743 if (ip_ipsec_fwd(m))
744 goto bad;
745#endif /* IPSEC */
746 ip_forward(m, dchg);
747 }
748 return;
749
750ours:
751#ifdef IPSTEALTH
752 /*
753 * IPSTEALTH: Process non-routing options only
754 * if the packet is destined for us.
755 */
756 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) {
757 if (ia != NULL)
758 ifa_free(&ia->ia_ifa);
759 return;
760 }
761#endif /* IPSTEALTH */
762
763 /* Count the packet in the ip address stats */
764 if (ia != NULL) {
765 ia->ia_ifa.if_ipackets++;
766 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
767 ifa_free(&ia->ia_ifa);
768 }
769
770 /*
771 * Attempt reassembly; if it succeeds, proceed.
772 * ip_reass() will return a different mbuf.
773 */
774 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
775 m = ip_reass(m);
776 if (m == NULL)
777 return;
778 ip = mtod(m, struct ip *);
779 /* Get the header length of the reassembled packet */
780 hlen = ip->ip_hl << 2;
781 }
782
783 /*
784 * Further protocols expect the packet length to be w/o the
785 * IP header.
786 */
787 ip->ip_len -= hlen;
788
789#ifdef IPSEC
790 /*
791 * enforce IPsec policy checking if we are seeing last header.
792 * note that we do not visit this with protocols with pcb layer
793 * code - like udp/tcp/raw ip.
794 */
795 if (ip_ipsec_input(m))
796 goto bad;
797#endif /* IPSEC */
798
799 /*
800 * Switch out to protocol's input routine.
801 */
802 IPSTAT_INC(ips_delivered);
803
804 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
805 return;
806bad:
807 m_freem(m);
808}
809
810/*
811 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
812 * max has slightly different semantics than the sysctl, for historical
813 * reasons.
814 */
815static void
816maxnipq_update(void)
817{
818
819 /*
820 * -1 for unlimited allocation.
821 */
822 if (V_maxnipq < 0)
823 uma_zone_set_max(V_ipq_zone, 0);
824 /*
825 * Positive number for specific bound.
826 */
827 if (V_maxnipq > 0)
828 uma_zone_set_max(V_ipq_zone, V_maxnipq);
829 /*
830 * Zero specifies no further fragment queue allocation -- set the
831 * bound very low, but rely on implementation elsewhere to actually
832 * prevent allocation and reclaim current queues.
833 */
834 if (V_maxnipq == 0)
835 uma_zone_set_max(V_ipq_zone, 1);
836}
837
838static void
839ipq_zone_change(void *tag)
840{
841
842 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) {
843 V_maxnipq = nmbclusters / 32;
844 maxnipq_update();
845 }
846}
847
848static int
849sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
850{
851 int error, i;
852
853 i = V_maxnipq;
854 error = sysctl_handle_int(oidp, &i, 0, req);
855 if (error || !req->newptr)
856 return (error);
857
858 /*
859 * XXXRW: Might be a good idea to sanity check the argument and place
860 * an extreme upper bound.
861 */
862 if (i < -1)
863 return (EINVAL);
864 V_maxnipq = i;
865 maxnipq_update();
866 return (0);
867}
868
869SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
870 NULL, 0, sysctl_maxnipq, "I",
871 "Maximum number of IPv4 fragment reassembly queue entries");
872
873/*
874 * Take incoming datagram fragment and try to reassemble it into
875 * whole datagram. If the argument is the first fragment or one
876 * in between the function will return NULL and store the mbuf
877 * in the fragment chain. If the argument is the last fragment
878 * the packet will be reassembled and the pointer to the new
879 * mbuf returned for further processing. Only m_tags attached
880 * to the first packet/fragment are preserved.
881 * The IP header is *NOT* adjusted out of iplen.
882 */
883struct mbuf *
884ip_reass(struct mbuf *m)
885{
886 struct ip *ip;
887 struct mbuf *p, *q, *nq, *t;
888 struct ipq *fp = NULL;
889 struct ipqhead *head;
890 int i, hlen, next;
891 u_int8_t ecn, ecn0;
892 u_short hash;
893
894 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
895 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) {
896 IPSTAT_INC(ips_fragments);
897 IPSTAT_INC(ips_fragdropped);
898 m_freem(m);
899 return (NULL);
900 }
901
902 ip = mtod(m, struct ip *);
903 hlen = ip->ip_hl << 2;
904
905 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
906 head = &V_ipq[hash];
907 IPQ_LOCK();
908
909 /*
910 * Look for queue of fragments
911 * of this datagram.
912 */
913 TAILQ_FOREACH(fp, head, ipq_list)
914 if (ip->ip_id == fp->ipq_id &&
915 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
916 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
917#ifdef MAC
918 mac_ipq_match(m, fp) &&
919#endif
920 ip->ip_p == fp->ipq_p)
921 goto found;
922
923 fp = NULL;
924
925 /*
926 * Attempt to trim the number of allocated fragment queues if it
927 * exceeds the administrative limit.
928 */
929 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) {
930 /*
931 * drop something from the tail of the current queue
932 * before proceeding further
933 */
934 struct ipq *q = TAILQ_LAST(head, ipqhead);
935 if (q == NULL) { /* gak */
936 for (i = 0; i < IPREASS_NHASH; i++) {
937 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead);
938 if (r) {
939 IPSTAT_ADD(ips_fragtimeout,
940 r->ipq_nfrags);
941 ip_freef(&V_ipq[i], r);
942 break;
943 }
944 }
945 } else {
946 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags);
947 ip_freef(head, q);
948 }
949 }
950
951found:
952 /*
953 * Adjust ip_len to not reflect header,
954 * convert offset of this to bytes.
955 */
956 ip->ip_len -= hlen;
957 if (ip->ip_off & IP_MF) {
958 /*
959 * Make sure that fragments have a data length
960 * that's a non-zero multiple of 8 bytes.
961 */
962 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
963 IPSTAT_INC(ips_toosmall); /* XXX */
964 goto dropfrag;
965 }
966 m->m_flags |= M_FRAG;
967 } else
968 m->m_flags &= ~M_FRAG;
969 ip->ip_off <<= 3;
970
971
972 /*
973 * Attempt reassembly; if it succeeds, proceed.
974 * ip_reass() will return a different mbuf.
975 */
976 IPSTAT_INC(ips_fragments);
977 m->m_pkthdr.header = ip;
978
979 /* Previous ip_reass() started here. */
980 /*
981 * Presence of header sizes in mbufs
982 * would confuse code below.
983 */
984 m->m_data += hlen;
985 m->m_len -= hlen;
986
987 /*
988 * If first fragment to arrive, create a reassembly queue.
989 */
990 if (fp == NULL) {
991 fp = uma_zalloc(V_ipq_zone, M_NOWAIT);
992 if (fp == NULL)
993 goto dropfrag;
994#ifdef MAC
995 if (mac_ipq_init(fp, M_NOWAIT) != 0) {
996 uma_zfree(V_ipq_zone, fp);
997 fp = NULL;
998 goto dropfrag;
999 }
1000 mac_ipq_create(m, fp);
1001#endif
1002 TAILQ_INSERT_HEAD(head, fp, ipq_list);
1003 V_nipq++;
1004 fp->ipq_nfrags = 1;
1005 fp->ipq_ttl = IPFRAGTTL;
1006 fp->ipq_p = ip->ip_p;
1007 fp->ipq_id = ip->ip_id;
1008 fp->ipq_src = ip->ip_src;
1009 fp->ipq_dst = ip->ip_dst;
1010 fp->ipq_frags = m;
1011 m->m_nextpkt = NULL;
1012 goto done;
1013 } else {
1014 fp->ipq_nfrags++;
1015#ifdef MAC
1016 mac_ipq_update(m, fp);
1017#endif
1018 }
1019
1020#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
1021
1022 /*
1023 * Handle ECN by comparing this segment with the first one;
1024 * if CE is set, do not lose CE.
1025 * drop if CE and not-ECT are mixed for the same packet.
1026 */
1027 ecn = ip->ip_tos & IPTOS_ECN_MASK;
1028 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
1029 if (ecn == IPTOS_ECN_CE) {
1030 if (ecn0 == IPTOS_ECN_NOTECT)
1031 goto dropfrag;
1032 if (ecn0 != IPTOS_ECN_CE)
1033 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
1034 }
1035 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
1036 goto dropfrag;
1037
1038 /*
1039 * Find a segment which begins after this one does.
1040 */
1041 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
1042 if (GETIP(q)->ip_off > ip->ip_off)
1043 break;
1044
1045 /*
1046 * If there is a preceding segment, it may provide some of
1047 * our data already. If so, drop the data from the incoming
1048 * segment. If it provides all of our data, drop us, otherwise
1049 * stick new segment in the proper place.
1050 *
1051 * If some of the data is dropped from the the preceding
1052 * segment, then it's checksum is invalidated.
1053 */
1054 if (p) {
1055 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
1056 if (i > 0) {
1057 if (i >= ip->ip_len)
1058 goto dropfrag;
1059 m_adj(m, i);
1060 m->m_pkthdr.csum_flags = 0;
1061 ip->ip_off += i;
1062 ip->ip_len -= i;
1063 }
1064 m->m_nextpkt = p->m_nextpkt;
1065 p->m_nextpkt = m;
1066 } else {
1067 m->m_nextpkt = fp->ipq_frags;
1068 fp->ipq_frags = m;
1069 }
1070
1071 /*
1072 * While we overlap succeeding segments trim them or,
1073 * if they are completely covered, dequeue them.
1074 */
1075 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
1076 q = nq) {
1077 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
1078 if (i < GETIP(q)->ip_len) {
1079 GETIP(q)->ip_len -= i;
1080 GETIP(q)->ip_off += i;
1081 m_adj(q, i);
1082 q->m_pkthdr.csum_flags = 0;
1083 break;
1084 }
1085 nq = q->m_nextpkt;
1086 m->m_nextpkt = nq;
1087 IPSTAT_INC(ips_fragdropped);
1088 fp->ipq_nfrags--;
1089 m_freem(q);
1090 }
1091
1092 /*
1093 * Check for complete reassembly and perform frag per packet
1094 * limiting.
1095 *
1096 * Frag limiting is performed here so that the nth frag has
1097 * a chance to complete the packet before we drop the packet.
1098 * As a result, n+1 frags are actually allowed per packet, but
1099 * only n will ever be stored. (n = maxfragsperpacket.)
1100 *
1101 */
1102 next = 0;
1103 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1104 if (GETIP(q)->ip_off != next) {
1105 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1106 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1107 ip_freef(head, fp);
1108 }
1109 goto done;
1110 }
1111 next += GETIP(q)->ip_len;
1112 }
1113 /* Make sure the last packet didn't have the IP_MF flag */
1114 if (p->m_flags & M_FRAG) {
1115 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1116 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1117 ip_freef(head, fp);
1118 }
1119 goto done;
1120 }
1121
1122 /*
1123 * Reassembly is complete. Make sure the packet is a sane size.
1124 */
1125 q = fp->ipq_frags;
1126 ip = GETIP(q);
1127 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
1128 IPSTAT_INC(ips_toolong);
1129 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1130 ip_freef(head, fp);
1131 goto done;
1132 }
1133
1134 /*
1135 * Concatenate fragments.
1136 */
1137 m = q;
1138 t = m->m_next;
1139 m->m_next = NULL;
1140 m_cat(m, t);
1141 nq = q->m_nextpkt;
1142 q->m_nextpkt = NULL;
1143 for (q = nq; q != NULL; q = nq) {
1144 nq = q->m_nextpkt;
1145 q->m_nextpkt = NULL;
1146 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1147 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1148 m_cat(m, q);
1149 }
1150 /*
1151 * In order to do checksumming faster we do 'end-around carry' here
1152 * (and not in for{} loop), though it implies we are not going to
1153 * reassemble more than 64k fragments.
1154 */
1155 m->m_pkthdr.csum_data =
1156 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16);
1157#ifdef MAC
1158 mac_ipq_reassemble(fp, m);
1159 mac_ipq_destroy(fp);
1160#endif
1161
1162 /*
1163 * Create header for new ip packet by modifying header of first
1164 * packet; dequeue and discard fragment reassembly header.
1165 * Make header visible.
1166 */
1167 ip->ip_len = (ip->ip_hl << 2) + next;
1168 ip->ip_src = fp->ipq_src;
1169 ip->ip_dst = fp->ipq_dst;
1170 TAILQ_REMOVE(head, fp, ipq_list);
1171 V_nipq--;
1172 uma_zfree(V_ipq_zone, fp);
1173 m->m_len += (ip->ip_hl << 2);
1174 m->m_data -= (ip->ip_hl << 2);
1175 /* some debugging cruft by sklower, below, will go away soon */
1176 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
1177 m_fixhdr(m);
1178 IPSTAT_INC(ips_reassembled);
1179 IPQ_UNLOCK();
1180 return (m);
1181
1182dropfrag:
1183 IPSTAT_INC(ips_fragdropped);
1184 if (fp != NULL)
1185 fp->ipq_nfrags--;
1186 m_freem(m);
1187done:
1188 IPQ_UNLOCK();
1189 return (NULL);
1190
1191#undef GETIP
1192}
1193
1194/*
1195 * Free a fragment reassembly header and all
1196 * associated datagrams.
1197 */
1198static void
1199ip_freef(struct ipqhead *fhp, struct ipq *fp)
1200{
1201 struct mbuf *q;
1202
1203 IPQ_LOCK_ASSERT();
1204
1205 while (fp->ipq_frags) {
1206 q = fp->ipq_frags;
1207 fp->ipq_frags = q->m_nextpkt;
1208 m_freem(q);
1209 }
1210 TAILQ_REMOVE(fhp, fp, ipq_list);
1211 uma_zfree(V_ipq_zone, fp);
1212 V_nipq--;
1213}
1214
1215/*
1216 * IP timer processing;
1217 * if a timer expires on a reassembly
1218 * queue, discard it.
1219 */
1220void
1221ip_slowtimo(void)
1222{
1223 VNET_ITERATOR_DECL(vnet_iter);
1224 struct ipq *fp;
1225 int i;
1226
1227 VNET_LIST_RLOCK_NOSLEEP();
1228 IPQ_LOCK();
1229 VNET_FOREACH(vnet_iter) {
1230 CURVNET_SET(vnet_iter);
1231 for (i = 0; i < IPREASS_NHASH; i++) {
1232 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) {
1233 struct ipq *fpp;
1234
1235 fpp = fp;
1236 fp = TAILQ_NEXT(fp, ipq_list);
1237 if(--fpp->ipq_ttl == 0) {
1238 IPSTAT_ADD(ips_fragtimeout,
1239 fpp->ipq_nfrags);
1240 ip_freef(&V_ipq[i], fpp);
1241 }
1242 }
1243 }
1244 /*
1245 * If we are over the maximum number of fragments
1246 * (due to the limit being lowered), drain off
1247 * enough to get down to the new limit.
1248 */
1249 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) {
1250 for (i = 0; i < IPREASS_NHASH; i++) {
1251 while (V_nipq > V_maxnipq &&
1252 !TAILQ_EMPTY(&V_ipq[i])) {
1253 IPSTAT_ADD(ips_fragdropped,
1254 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1255 ip_freef(&V_ipq[i],
1256 TAILQ_FIRST(&V_ipq[i]));
1257 }
1258 }
1259 }
1260 CURVNET_RESTORE();
1261 }
1262 IPQ_UNLOCK();
1263 VNET_LIST_RUNLOCK_NOSLEEP();
1264}
1265
1266/*
1267 * Drain off all datagram fragments.
1268 */
1269static void
1270ip_drain_locked(void)
1271{
1272 int i;
1273
1274 IPQ_LOCK_ASSERT();
1275
1276 for (i = 0; i < IPREASS_NHASH; i++) {
1277 while(!TAILQ_EMPTY(&V_ipq[i])) {
1278 IPSTAT_ADD(ips_fragdropped,
1279 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1280 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i]));
1281 }
1282 }
1283}
1284
1285void
1286ip_drain(void)
1287{
1288 VNET_ITERATOR_DECL(vnet_iter);
1289
1290 VNET_LIST_RLOCK_NOSLEEP();
1291 IPQ_LOCK();
1292 VNET_FOREACH(vnet_iter) {
1293 CURVNET_SET(vnet_iter);
1294 ip_drain_locked();
1295 CURVNET_RESTORE();
1296 }
1297 IPQ_UNLOCK();
1298 VNET_LIST_RUNLOCK_NOSLEEP();
1299 in_rtqdrain();
1300}
1301
1302/*
1303 * The protocol to be inserted into ip_protox[] must be already registered
1304 * in inetsw[], either statically or through pf_proto_register().
1305 */
1306int
1307ipproto_register(u_char ipproto)
1308{
1309 struct protosw *pr;
1310
1311 /* Sanity checks. */
1312 if (ipproto == 0)
1313 return (EPROTONOSUPPORT);
1314
1315 /*
1316 * The protocol slot must not be occupied by another protocol
1317 * already. An index pointing to IPPROTO_RAW is unused.
1318 */
1319 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1320 if (pr == NULL)
1321 return (EPFNOSUPPORT);
1322 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
1323 return (EEXIST);
1324
1325 /* Find the protocol position in inetsw[] and set the index. */
1326 for (pr = inetdomain.dom_protosw;
1327 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
1328 if (pr->pr_domain->dom_family == PF_INET &&
1329 pr->pr_protocol && pr->pr_protocol == ipproto) {
1330 /* Be careful to only index valid IP protocols. */
1331 if (pr->pr_protocol < IPPROTO_MAX) {
1332 ip_protox[pr->pr_protocol] = pr - inetsw;
1333 return (0);
1334 } else
1335 return (EINVAL);
1336 }
1337 }
1338 return (EPROTONOSUPPORT);
1339}
1340
1341int
1342ipproto_unregister(u_char ipproto)
1343{
1344 struct protosw *pr;
1345
1346 /* Sanity checks. */
1347 if (ipproto == 0)
1348 return (EPROTONOSUPPORT);
1349
1350 /* Check if the protocol was indeed registered. */
1351 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1352 if (pr == NULL)
1353 return (EPFNOSUPPORT);
1354 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
1355 return (ENOENT);
1356
1357 /* Reset the protocol slot to IPPROTO_RAW. */
1358 ip_protox[ipproto] = pr - inetsw;
1359 return (0);
1360}
1361
1362/*
1363 * Given address of next destination (final or next hop), return (referenced)
1364 * internet address info of interface to be used to get there.
1365 */
1366struct in_ifaddr *
1367ip_rtaddr(struct in_addr dst, u_int fibnum)
1368{
1369 struct route sro;
1370 struct sockaddr_in *sin;
1371 struct in_ifaddr *ia;
1372
1373 bzero(&sro, sizeof(sro));
1374 sin = (struct sockaddr_in *)&sro.ro_dst;
1375 sin->sin_family = AF_INET;
1376 sin->sin_len = sizeof(*sin);
1377 sin->sin_addr = dst;
1378 in_rtalloc_ign(&sro, 0, fibnum);
1379
1380 if (sro.ro_rt == NULL)
1381 return (NULL);
1382
1383 ia = ifatoia(sro.ro_rt->rt_ifa);
1384 ifa_ref(&ia->ia_ifa);
1385 RTFREE(sro.ro_rt);
1386 return (ia);
1387}
1388
1389u_char inetctlerrmap[PRC_NCMDS] = {
1390 0, 0, 0, 0,
1391 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1392 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1393 EMSGSIZE, EHOSTUNREACH, 0, 0,
1394 0, 0, EHOSTUNREACH, 0,
1395 ENOPROTOOPT, ECONNREFUSED
1396};
1397
1398/*
1399 * Forward a packet. If some error occurs return the sender
1400 * an icmp packet. Note we can't always generate a meaningful
1401 * icmp message because icmp doesn't have a large enough repertoire
1402 * of codes and types.
1403 *
1404 * If not forwarding, just drop the packet. This could be confusing
1405 * if ipforwarding was zero but some routing protocol was advancing
1406 * us as a gateway to somewhere. However, we must let the routing
1407 * protocol deal with that.
1408 *
1409 * The srcrt parameter indicates whether the packet is being forwarded
1410 * via a source route.
1411 */
1412void
1413ip_forward(struct mbuf *m, int srcrt)
1414{
1415 struct ip *ip = mtod(m, struct ip *);
1416 struct in_ifaddr *ia;
1417 struct mbuf *mcopy;
1418 struct in_addr dest;
1419 struct route ro;
1420 int error, type = 0, code = 0, mtu = 0;
1421
1422 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1423 IPSTAT_INC(ips_cantforward);
1424 m_freem(m);
1425 return;
1426 }
1427#ifdef IPSTEALTH
1428 if (!V_ipstealth) {
1429#endif
1430 if (ip->ip_ttl <= IPTTLDEC) {
1431 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
1432 0, 0);
1433 return;
1434 }
1435#ifdef IPSTEALTH
1436 }
1437#endif
1438
1439 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
1440#ifndef IPSEC
1441 /*
1442 * 'ia' may be NULL if there is no route for this destination.
1443 * In case of IPsec, Don't discard it just yet, but pass it to
1444 * ip_output in case of outgoing IPsec policy.
1445 */
1446 if (!srcrt && ia == NULL) {
1447 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
1448 return;
1449 }
1450#endif
1451
1452 /*
1453 * Save the IP header and at most 8 bytes of the payload,
1454 * in case we need to generate an ICMP message to the src.
1455 *
1456 * XXX this can be optimized a lot by saving the data in a local
1457 * buffer on the stack (72 bytes at most), and only allocating the
1458 * mbuf if really necessary. The vast majority of the packets
1459 * are forwarded without having to send an ICMP back (either
1460 * because unnecessary, or because rate limited), so we are
1461 * really we are wasting a lot of work here.
1462 *
1463 * We don't use m_copy() because it might return a reference
1464 * to a shared cluster. Both this function and ip_output()
1465 * assume exclusive access to the IP header in `m', so any
1466 * data in a cluster may change before we reach icmp_error().
1467 */
1468 MGETHDR(mcopy, M_DONTWAIT, m->m_type);
1469 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) {
1470 /*
1471 * It's probably ok if the pkthdr dup fails (because
1472 * the deep copy of the tag chain failed), but for now
1473 * be conservative and just discard the copy since
1474 * code below may some day want the tags.
1475 */
1476 m_free(mcopy);
1477 mcopy = NULL;
1478 }
1479 if (mcopy != NULL) {
1480 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy));
1481 mcopy->m_pkthdr.len = mcopy->m_len;
1482 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1483 }
1484
1485#ifdef IPSTEALTH
1486 if (!V_ipstealth) {
1487#endif
1488 ip->ip_ttl -= IPTTLDEC;
1489#ifdef IPSTEALTH
1490 }
1491#endif
1492
1493 /*
1494 * If forwarding packet using same interface that it came in on,
1495 * perhaps should send a redirect to sender to shortcut a hop.
1496 * Only send redirect if source is sending directly to us,
1497 * and if packet was not source routed (or has any options).
1498 * Also, don't send redirect if forwarding using a default route
1499 * or a route modified by a redirect.
1500 */
1501 dest.s_addr = 0;
1502 if (!srcrt && V_ipsendredirects &&
1503 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
1504 struct sockaddr_in *sin;
1505 struct rtentry *rt;
1506
1507 bzero(&ro, sizeof(ro));
1508 sin = (struct sockaddr_in *)&ro.ro_dst;
1509 sin->sin_family = AF_INET;
1510 sin->sin_len = sizeof(*sin);
1511 sin->sin_addr = ip->ip_dst;
1512 in_rtalloc_ign(&ro, 0, M_GETFIB(m));
1513
1514 rt = ro.ro_rt;
1515
1516 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1517 satosin(rt_key(rt))->sin_addr.s_addr != 0) {
1518#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1519 u_long src = ntohl(ip->ip_src.s_addr);
1520
1521 if (RTA(rt) &&
1522 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1523 if (rt->rt_flags & RTF_GATEWAY)
1524 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
1525 else
1526 dest.s_addr = ip->ip_dst.s_addr;
1527 /* Router requirements says to only send host redirects */
1528 type = ICMP_REDIRECT;
1529 code = ICMP_REDIRECT_HOST;
1530 }
1531 }
1532 if (rt)
1533 RTFREE(rt);
1534 }
1535
1536 /*
1537 * Try to cache the route MTU from ip_output so we can consider it for
1538 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191.
1539 */
1540 bzero(&ro, sizeof(ro));
1541
1542 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
1543
1544 if (error == EMSGSIZE && ro.ro_rt)
1545 mtu = ro.ro_rt->rt_rmx.rmx_mtu;
1546 if (ro.ro_rt)
1547 RTFREE(ro.ro_rt);
1548
1549 if (error)
1550 IPSTAT_INC(ips_cantforward);
1551 else {
1552 IPSTAT_INC(ips_forward);
1553 if (type)
1554 IPSTAT_INC(ips_redirectsent);
1555 else {
1556 if (mcopy)
1557 m_freem(mcopy);
1558 if (ia != NULL)
1559 ifa_free(&ia->ia_ifa);
1560 return;
1561 }
1562 }
1563 if (mcopy == NULL) {
1564 if (ia != NULL)
1565 ifa_free(&ia->ia_ifa);
1566 return;
1567 }
1568
1569 switch (error) {
1570
1571 case 0: /* forwarded, but need redirect */
1572 /* type, code set above */
1573 break;
1574
1575 case ENETUNREACH:
1576 case EHOSTUNREACH:
1577 case ENETDOWN:
1578 case EHOSTDOWN:
1579 default:
1580 type = ICMP_UNREACH;
1581 code = ICMP_UNREACH_HOST;
1582 break;
1583
1584 case EMSGSIZE:
1585 type = ICMP_UNREACH;
1586 code = ICMP_UNREACH_NEEDFRAG;
1587
1588#ifdef IPSEC
1589 /*
1590 * If IPsec is configured for this path,
1591 * override any possibly mtu value set by ip_output.
1592 */
1593 mtu = ip_ipsec_mtu(mcopy, mtu);
1594#endif /* IPSEC */
1595 /*
1596 * If the MTU was set before make sure we are below the
1597 * interface MTU.
1598 * If the MTU wasn't set before use the interface mtu or
1599 * fall back to the next smaller mtu step compared to the
1600 * current packet size.
1601 */
1602 if (mtu != 0) {
1603 if (ia != NULL)
1604 mtu = min(mtu, ia->ia_ifp->if_mtu);
1605 } else {
1606 if (ia != NULL)
1607 mtu = ia->ia_ifp->if_mtu;
1608 else
1609 mtu = ip_next_mtu(ip->ip_len, 0);
1610 }
1611 IPSTAT_INC(ips_cantfrag);
1612 break;
1613
1614 case ENOBUFS:
1615 /*
1616 * A router should not generate ICMP_SOURCEQUENCH as
1617 * required in RFC1812 Requirements for IP Version 4 Routers.
1618 * Source quench could be a big problem under DoS attacks,
1619 * or if the underlying interface is rate-limited.
1620 * Those who need source quench packets may re-enable them
1621 * via the net.inet.ip.sendsourcequench sysctl.
1622 */
1623 if (V_ip_sendsourcequench == 0) {
1624 m_freem(mcopy);
1625 if (ia != NULL)
1626 ifa_free(&ia->ia_ifa);
1627 return;
1628 } else {
1629 type = ICMP_SOURCEQUENCH;
1630 code = 0;
1631 }
1632 break;
1633
1634 case EACCES: /* ipfw denied packet */
1635 m_freem(mcopy);
1636 if (ia != NULL)
1637 ifa_free(&ia->ia_ifa);
1638 return;
1639 }
1640 if (ia != NULL)
1641 ifa_free(&ia->ia_ifa);
1642 icmp_error(mcopy, type, code, dest.s_addr, mtu);
1643}
1644
1645void
1646ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1647 struct mbuf *m)
1648{
1649
1650 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) {
1651 struct bintime bt;
1652
1653 bintime(&bt);
1654 if (inp->inp_socket->so_options & SO_BINTIME) {
1655 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt),
1656 SCM_BINTIME, SOL_SOCKET);
1657 if (*mp)
1658 mp = &(*mp)->m_next;
1659 }
1660 if (inp->inp_socket->so_options & SO_TIMESTAMP) {
1661 struct timeval tv;
1662
1663 bintime2timeval(&bt, &tv);
1664 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1665 SCM_TIMESTAMP, SOL_SOCKET);
1666 if (*mp)
1667 mp = &(*mp)->m_next;
1668 }
1669 }
1670 if (inp->inp_flags & INP_RECVDSTADDR) {
1671 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
1672 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1673 if (*mp)
1674 mp = &(*mp)->m_next;
1675 }
1676 if (inp->inp_flags & INP_RECVTTL) {
1677 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl,
1678 sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
1679 if (*mp)
1680 mp = &(*mp)->m_next;
1681 }
1682#ifdef notyet
1683 /* XXX
1684 * Moving these out of udp_input() made them even more broken
1685 * than they already were.
1686 */
1687 /* options were tossed already */
1688 if (inp->inp_flags & INP_RECVOPTS) {
1689 *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
1690 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
1691 if (*mp)
1692 mp = &(*mp)->m_next;
1693 }
1694 /* ip_srcroute doesn't do what we want here, need to fix */
1695 if (inp->inp_flags & INP_RECVRETOPTS) {
1696 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m),
1697 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
1698 if (*mp)
1699 mp = &(*mp)->m_next;
1700 }
1701#endif
1702 if (inp->inp_flags & INP_RECVIF) {
1703 struct ifnet *ifp;
1704 struct sdlbuf {
1705 struct sockaddr_dl sdl;
1706 u_char pad[32];
1707 } sdlbuf;
1708 struct sockaddr_dl *sdp;
1709 struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
1710
1711 if (((ifp = m->m_pkthdr.rcvif))
1712 && ( ifp->if_index && (ifp->if_index <= V_if_index))) {
1713 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
1714 /*
1715 * Change our mind and don't try copy.
1716 */
1717 if ((sdp->sdl_family != AF_LINK)
1718 || (sdp->sdl_len > sizeof(sdlbuf))) {
1719 goto makedummy;
1720 }
1721 bcopy(sdp, sdl2, sdp->sdl_len);
1722 } else {
1723makedummy:
1724 sdl2->sdl_len
1725 = offsetof(struct sockaddr_dl, sdl_data[0]);
1726 sdl2->sdl_family = AF_LINK;
1727 sdl2->sdl_index = 0;
1728 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
1729 }
1730 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
1731 IP_RECVIF, IPPROTO_IP);
1732 if (*mp)
1733 mp = &(*mp)->m_next;
1734 }
1735}
1736
1737/*
1738 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
1739 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
1740 * locking. This code remains in ip_input.c as ip_mroute.c is optionally
1741 * compiled.
1742 */
| 209SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
210 &VNET_NAME(ipstealth), 0,
211 "IP stealth mode, no TTL decrementation on forwarding");
212#endif
213
214#ifdef FLOWTABLE
215static VNET_DEFINE(int, ip_output_flowtable_size) = 2048;
216VNET_DEFINE(struct flowtable *, ip_ft);
217#define V_ip_output_flowtable_size VNET(ip_output_flowtable_size)
218
219SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN,
220 &VNET_NAME(ip_output_flowtable_size), 2048,
221 "number of entries in the per-cpu output flow caches");
222#endif
223
224VNET_DEFINE(int, fw_one_pass) = 1;
225
226static void ip_freef(struct ipqhead *, struct ipq *);
227
228/*
229 * Kernel module interface for updating ipstat. The argument is an index
230 * into ipstat treated as an array of u_long. While this encodes the general
231 * layout of ipstat into the caller, it doesn't encode its location, so that
232 * future changes to add, for example, per-CPU stats support won't cause
233 * binary compatibility problems for kernel modules.
234 */
235void
236kmod_ipstat_inc(int statnum)
237{
238
239 (*((u_long *)&V_ipstat + statnum))++;
240}
241
242void
243kmod_ipstat_dec(int statnum)
244{
245
246 (*((u_long *)&V_ipstat + statnum))--;
247}
248
249static int
250sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
251{
252 int error, qlimit;
253
254 netisr_getqlimit(&ip_nh, &qlimit);
255 error = sysctl_handle_int(oidp, &qlimit, 0, req);
256 if (error || !req->newptr)
257 return (error);
258 if (qlimit < 1)
259 return (EINVAL);
260 return (netisr_setqlimit(&ip_nh, qlimit));
261}
262SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
263 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I",
264 "Maximum size of the IP input queue");
265
266static int
267sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
268{
269 u_int64_t qdrops_long;
270 int error, qdrops;
271
272 netisr_getqdrops(&ip_nh, &qdrops_long);
273 qdrops = qdrops_long;
274 error = sysctl_handle_int(oidp, &qdrops, 0, req);
275 if (error || !req->newptr)
276 return (error);
277 if (qdrops != 0)
278 return (EINVAL);
279 netisr_clearqdrops(&ip_nh);
280 return (0);
281}
282
283SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
284 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I",
285 "Number of packets dropped from the IP input queue");
286
287/*
288 * IP initialization: fill in IP protocol switch table.
289 * All protocols not implemented in kernel go to raw IP protocol handler.
290 */
291void
292ip_init(void)
293{
294 struct protosw *pr;
295 int i;
296
297 V_ip_id = time_second & 0xffff;
298
299 TAILQ_INIT(&V_in_ifaddrhead);
300 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
301
302 /* Initialize IP reassembly queue. */
303 for (i = 0; i < IPREASS_NHASH; i++)
304 TAILQ_INIT(&V_ipq[i]);
305 V_maxnipq = nmbclusters / 32;
306 V_maxfragsperpacket = 16;
307 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
308 NULL, UMA_ALIGN_PTR, 0);
309 maxnipq_update();
310
311 /* Initialize packet filter hooks. */
312 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF;
313 V_inet_pfil_hook.ph_af = AF_INET;
314 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0)
315 printf("%s: WARNING: unable to register pfil hook, "
316 "error %d\n", __func__, i);
317
318#ifdef FLOWTABLE
319 if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size",
320 &V_ip_output_flowtable_size)) {
321 if (V_ip_output_flowtable_size < 256)
322 V_ip_output_flowtable_size = 256;
323 if (!powerof2(V_ip_output_flowtable_size)) {
324 printf("flowtable must be power of 2 size\n");
325 V_ip_output_flowtable_size = 2048;
326 }
327 } else {
328 /*
329 * round up to the next power of 2
330 */
331 V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1);
332 }
333 V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU);
334#endif
335
336 /* Skip initialization of globals for non-default instances. */
337 if (!IS_DEFAULT_VNET(curvnet))
338 return;
339
340 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
341 if (pr == NULL)
342 panic("ip_init: PF_INET not found");
343
344 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
345 for (i = 0; i < IPPROTO_MAX; i++)
346 ip_protox[i] = pr - inetsw;
347 /*
348 * Cycle through IP protocols and put them into the appropriate place
349 * in ip_protox[].
350 */
351 for (pr = inetdomain.dom_protosw;
352 pr < inetdomain.dom_protoswNPROTOSW; pr++)
353 if (pr->pr_domain->dom_family == PF_INET &&
354 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
355 /* Be careful to only index valid IP protocols. */
356 if (pr->pr_protocol < IPPROTO_MAX)
357 ip_protox[pr->pr_protocol] = pr - inetsw;
358 }
359
360 /* Start ipport_tick. */
361 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE);
362 callout_reset(&ipport_tick_callout, 1, ipport_tick, NULL);
363 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL,
364 SHUTDOWN_PRI_DEFAULT);
365 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change,
366 NULL, EVENTHANDLER_PRI_ANY);
367
368 /* Initialize various other remaining things. */
369 IPQ_LOCK_INIT();
370 netisr_register(&ip_nh);
371}
372
373#ifdef VIMAGE
374void
375ip_destroy(void)
376{
377
378 /* Cleanup in_ifaddr hash table; should be empty. */
379 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
380
381 IPQ_LOCK();
382 ip_drain_locked();
383 IPQ_UNLOCK();
384
385 uma_zdestroy(V_ipq_zone);
386}
387#endif
388
389void
390ip_fini(void *xtp)
391{
392
393 callout_stop(&ipport_tick_callout);
394}
395
396/*
397 * Ip input routine. Checksum and byte swap header. If fragmented
398 * try to reassemble. Process options. Pass to next level.
399 */
400void
401ip_input(struct mbuf *m)
402{
403 struct ip *ip = NULL;
404 struct in_ifaddr *ia = NULL;
405 struct ifaddr *ifa;
406 struct ifnet *ifp;
407 int checkif, hlen = 0;
408 u_short sum;
409 int dchg = 0; /* dest changed after fw */
410 struct in_addr odst; /* original dst address */
411
412 M_ASSERTPKTHDR(m);
413
414 if (m->m_flags & M_FASTFWD_OURS) {
415 /*
416 * Firewall or NAT changed destination to local.
417 * We expect ip_len and ip_off to be in host byte order.
418 */
419 m->m_flags &= ~M_FASTFWD_OURS;
420 /* Set up some basics that will be used later. */
421 ip = mtod(m, struct ip *);
422 hlen = ip->ip_hl << 2;
423 goto ours;
424 }
425
426 IPSTAT_INC(ips_total);
427
428 if (m->m_pkthdr.len < sizeof(struct ip))
429 goto tooshort;
430
431 if (m->m_len < sizeof (struct ip) &&
432 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
433 IPSTAT_INC(ips_toosmall);
434 return;
435 }
436 ip = mtod(m, struct ip *);
437
438 if (ip->ip_v != IPVERSION) {
439 IPSTAT_INC(ips_badvers);
440 goto bad;
441 }
442
443 hlen = ip->ip_hl << 2;
444 if (hlen < sizeof(struct ip)) { /* minimum header length */
445 IPSTAT_INC(ips_badhlen);
446 goto bad;
447 }
448 if (hlen > m->m_len) {
449 if ((m = m_pullup(m, hlen)) == NULL) {
450 IPSTAT_INC(ips_badhlen);
451 return;
452 }
453 ip = mtod(m, struct ip *);
454 }
455
456 /* 127/8 must not appear on wire - RFC1122 */
457 ifp = m->m_pkthdr.rcvif;
458 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
459 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
460 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
461 IPSTAT_INC(ips_badaddr);
462 goto bad;
463 }
464 }
465
466 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
467 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
468 } else {
469 if (hlen == sizeof(struct ip)) {
470 sum = in_cksum_hdr(ip);
471 } else {
472 sum = in_cksum(m, hlen);
473 }
474 }
475 if (sum) {
476 IPSTAT_INC(ips_badsum);
477 goto bad;
478 }
479
480#ifdef ALTQ
481 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
482 /* packet is dropped by traffic conditioner */
483 return;
484#endif
485
486 /*
487 * Convert fields to host representation.
488 */
489 ip->ip_len = ntohs(ip->ip_len);
490 if (ip->ip_len < hlen) {
491 IPSTAT_INC(ips_badlen);
492 goto bad;
493 }
494 ip->ip_off = ntohs(ip->ip_off);
495
496 /*
497 * Check that the amount of data in the buffers
498 * is as at least much as the IP header would have us expect.
499 * Trim mbufs if longer than we expect.
500 * Drop packet if shorter than we expect.
501 */
502 if (m->m_pkthdr.len < ip->ip_len) {
503tooshort:
504 IPSTAT_INC(ips_tooshort);
505 goto bad;
506 }
507 if (m->m_pkthdr.len > ip->ip_len) {
508 if (m->m_len == m->m_pkthdr.len) {
509 m->m_len = ip->ip_len;
510 m->m_pkthdr.len = ip->ip_len;
511 } else
512 m_adj(m, ip->ip_len - m->m_pkthdr.len);
513 }
514#ifdef IPSEC
515 /*
516 * Bypass packet filtering for packets from a tunnel (gif).
517 */
518 if (ip_ipsec_filtertunnel(m))
519 goto passin;
520#endif /* IPSEC */
521
522 /*
523 * Run through list of hooks for input packets.
524 *
525 * NB: Beware of the destination address changing (e.g.
526 * by NAT rewriting). When this happens, tell
527 * ip_forward to do the right thing.
528 */
529
530 /* Jump over all PFIL processing if hooks are not active. */
531 if (!PFIL_HOOKED(&V_inet_pfil_hook))
532 goto passin;
533
534 odst = ip->ip_dst;
535 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0)
536 return;
537 if (m == NULL) /* consumed by filter */
538 return;
539
540 ip = mtod(m, struct ip *);
541 dchg = (odst.s_addr != ip->ip_dst.s_addr);
542 ifp = m->m_pkthdr.rcvif;
543
544#ifdef IPFIREWALL_FORWARD
545 if (m->m_flags & M_FASTFWD_OURS) {
546 m->m_flags &= ~M_FASTFWD_OURS;
547 goto ours;
548 }
549 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) {
550 /*
551 * Directly ship the packet on. This allows forwarding
552 * packets originally destined to us to some other directly
553 * connected host.
554 */
555 ip_forward(m, dchg);
556 return;
557 }
558#endif /* IPFIREWALL_FORWARD */
559
560passin:
561 /*
562 * Process options and, if not destined for us,
563 * ship it on. ip_dooptions returns 1 when an
564 * error was detected (causing an icmp message
565 * to be sent and the original packet to be freed).
566 */
567 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
568 return;
569
570 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
571 * matter if it is destined to another node, or whether it is
572 * a multicast one, RSVP wants it! and prevents it from being forwarded
573 * anywhere else. Also checks if the rsvp daemon is running before
574 * grabbing the packet.
575 */
576 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP)
577 goto ours;
578
579 /*
580 * Check our list of addresses, to see if the packet is for us.
581 * If we don't have any addresses, assume any unicast packet
582 * we receive might be for us (and let the upper layers deal
583 * with it).
584 */
585 if (TAILQ_EMPTY(&V_in_ifaddrhead) &&
586 (m->m_flags & (M_MCAST|M_BCAST)) == 0)
587 goto ours;
588
589 /*
590 * Enable a consistency check between the destination address
591 * and the arrival interface for a unicast packet (the RFC 1122
592 * strong ES model) if IP forwarding is disabled and the packet
593 * is not locally generated and the packet is not subject to
594 * 'ipfw fwd'.
595 *
596 * XXX - Checking also should be disabled if the destination
597 * address is ipnat'ed to a different interface.
598 *
599 * XXX - Checking is incompatible with IP aliases added
600 * to the loopback interface instead of the interface where
601 * the packets are received.
602 *
603 * XXX - This is the case for carp vhost IPs as well so we
604 * insert a workaround. If the packet got here, we already
605 * checked with carp_iamatch() and carp_forus().
606 */
607 checkif = V_ip_checkinterface && (V_ipforwarding == 0) &&
608 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
609#ifdef DEV_CARP
610 !ifp->if_carp &&
611#endif
612 (dchg == 0);
613
614 /*
615 * Check for exact addresses in the hash bucket.
616 */
617 /* IN_IFADDR_RLOCK(); */
618 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
619 /*
620 * If the address matches, verify that the packet
621 * arrived via the correct interface if checking is
622 * enabled.
623 */
624 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
625 (!checkif || ia->ia_ifp == ifp)) {
626 ifa_ref(&ia->ia_ifa);
627 /* IN_IFADDR_RUNLOCK(); */
628 goto ours;
629 }
630 }
631 /* IN_IFADDR_RUNLOCK(); */
632
633 /*
634 * Check for broadcast addresses.
635 *
636 * Only accept broadcast packets that arrive via the matching
637 * interface. Reception of forwarded directed broadcasts would
638 * be handled via ip_forward() and ether_output() with the loopback
639 * into the stack for SIMPLEX interfaces handled by ether_output().
640 */
641 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
642 IF_ADDR_LOCK(ifp);
643 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
644 if (ifa->ifa_addr->sa_family != AF_INET)
645 continue;
646 ia = ifatoia(ifa);
647 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
648 ip->ip_dst.s_addr) {
649 ifa_ref(ifa);
650 IF_ADDR_UNLOCK(ifp);
651 goto ours;
652 }
653 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr) {
654 ifa_ref(ifa);
655 IF_ADDR_UNLOCK(ifp);
656 goto ours;
657 }
658#ifdef BOOTP_COMPAT
659 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
660 ifa_ref(ifa);
661 IF_ADDR_UNLOCK(ifp);
662 goto ours;
663 }
664#endif
665 }
666 IF_ADDR_UNLOCK(ifp);
667 ia = NULL;
668 }
669 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */
670 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
671 IPSTAT_INC(ips_cantforward);
672 m_freem(m);
673 return;
674 }
675 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
676 if (V_ip_mrouter) {
677 /*
678 * If we are acting as a multicast router, all
679 * incoming multicast packets are passed to the
680 * kernel-level multicast forwarding function.
681 * The packet is returned (relatively) intact; if
682 * ip_mforward() returns a non-zero value, the packet
683 * must be discarded, else it may be accepted below.
684 */
685 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
686 IPSTAT_INC(ips_cantforward);
687 m_freem(m);
688 return;
689 }
690
691 /*
692 * The process-level routing daemon needs to receive
693 * all multicast IGMP packets, whether or not this
694 * host belongs to their destination groups.
695 */
696 if (ip->ip_p == IPPROTO_IGMP)
697 goto ours;
698 IPSTAT_INC(ips_forward);
699 }
700 /*
701 * Assume the packet is for us, to avoid prematurely taking
702 * a lock on the in_multi hash. Protocols must perform
703 * their own filtering and update statistics accordingly.
704 */
705 goto ours;
706 }
707 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
708 goto ours;
709 if (ip->ip_dst.s_addr == INADDR_ANY)
710 goto ours;
711
712 /*
713 * FAITH(Firewall Aided Internet Translator)
714 */
715 if (ifp && ifp->if_type == IFT_FAITH) {
716 if (V_ip_keepfaith) {
717 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
718 goto ours;
719 }
720 m_freem(m);
721 return;
722 }
723
724 /*
725 * Not for us; forward if possible and desirable.
726 */
727 if (V_ipforwarding == 0) {
728 IPSTAT_INC(ips_cantforward);
729 m_freem(m);
730 } else {
731#ifdef IPSEC
732 if (ip_ipsec_fwd(m))
733 goto bad;
734#endif /* IPSEC */
735 ip_forward(m, dchg);
736 }
737 return;
738
739ours:
740#ifdef IPSTEALTH
741 /*
742 * IPSTEALTH: Process non-routing options only
743 * if the packet is destined for us.
744 */
745 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) {
746 if (ia != NULL)
747 ifa_free(&ia->ia_ifa);
748 return;
749 }
750#endif /* IPSTEALTH */
751
752 /* Count the packet in the ip address stats */
753 if (ia != NULL) {
754 ia->ia_ifa.if_ipackets++;
755 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
756 ifa_free(&ia->ia_ifa);
757 }
758
759 /*
760 * Attempt reassembly; if it succeeds, proceed.
761 * ip_reass() will return a different mbuf.
762 */
763 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
764 m = ip_reass(m);
765 if (m == NULL)
766 return;
767 ip = mtod(m, struct ip *);
768 /* Get the header length of the reassembled packet */
769 hlen = ip->ip_hl << 2;
770 }
771
772 /*
773 * Further protocols expect the packet length to be w/o the
774 * IP header.
775 */
776 ip->ip_len -= hlen;
777
778#ifdef IPSEC
779 /*
780 * enforce IPsec policy checking if we are seeing last header.
781 * note that we do not visit this with protocols with pcb layer
782 * code - like udp/tcp/raw ip.
783 */
784 if (ip_ipsec_input(m))
785 goto bad;
786#endif /* IPSEC */
787
788 /*
789 * Switch out to protocol's input routine.
790 */
791 IPSTAT_INC(ips_delivered);
792
793 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
794 return;
795bad:
796 m_freem(m);
797}
798
799/*
800 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
801 * max has slightly different semantics than the sysctl, for historical
802 * reasons.
803 */
804static void
805maxnipq_update(void)
806{
807
808 /*
809 * -1 for unlimited allocation.
810 */
811 if (V_maxnipq < 0)
812 uma_zone_set_max(V_ipq_zone, 0);
813 /*
814 * Positive number for specific bound.
815 */
816 if (V_maxnipq > 0)
817 uma_zone_set_max(V_ipq_zone, V_maxnipq);
818 /*
819 * Zero specifies no further fragment queue allocation -- set the
820 * bound very low, but rely on implementation elsewhere to actually
821 * prevent allocation and reclaim current queues.
822 */
823 if (V_maxnipq == 0)
824 uma_zone_set_max(V_ipq_zone, 1);
825}
826
827static void
828ipq_zone_change(void *tag)
829{
830
831 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) {
832 V_maxnipq = nmbclusters / 32;
833 maxnipq_update();
834 }
835}
836
837static int
838sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
839{
840 int error, i;
841
842 i = V_maxnipq;
843 error = sysctl_handle_int(oidp, &i, 0, req);
844 if (error || !req->newptr)
845 return (error);
846
847 /*
848 * XXXRW: Might be a good idea to sanity check the argument and place
849 * an extreme upper bound.
850 */
851 if (i < -1)
852 return (EINVAL);
853 V_maxnipq = i;
854 maxnipq_update();
855 return (0);
856}
857
858SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
859 NULL, 0, sysctl_maxnipq, "I",
860 "Maximum number of IPv4 fragment reassembly queue entries");
861
862/*
863 * Take incoming datagram fragment and try to reassemble it into
864 * whole datagram. If the argument is the first fragment or one
865 * in between the function will return NULL and store the mbuf
866 * in the fragment chain. If the argument is the last fragment
867 * the packet will be reassembled and the pointer to the new
868 * mbuf returned for further processing. Only m_tags attached
869 * to the first packet/fragment are preserved.
870 * The IP header is *NOT* adjusted out of iplen.
871 */
872struct mbuf *
873ip_reass(struct mbuf *m)
874{
875 struct ip *ip;
876 struct mbuf *p, *q, *nq, *t;
877 struct ipq *fp = NULL;
878 struct ipqhead *head;
879 int i, hlen, next;
880 u_int8_t ecn, ecn0;
881 u_short hash;
882
883 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
884 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) {
885 IPSTAT_INC(ips_fragments);
886 IPSTAT_INC(ips_fragdropped);
887 m_freem(m);
888 return (NULL);
889 }
890
891 ip = mtod(m, struct ip *);
892 hlen = ip->ip_hl << 2;
893
894 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
895 head = &V_ipq[hash];
896 IPQ_LOCK();
897
898 /*
899 * Look for queue of fragments
900 * of this datagram.
901 */
902 TAILQ_FOREACH(fp, head, ipq_list)
903 if (ip->ip_id == fp->ipq_id &&
904 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
905 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
906#ifdef MAC
907 mac_ipq_match(m, fp) &&
908#endif
909 ip->ip_p == fp->ipq_p)
910 goto found;
911
912 fp = NULL;
913
914 /*
915 * Attempt to trim the number of allocated fragment queues if it
916 * exceeds the administrative limit.
917 */
918 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) {
919 /*
920 * drop something from the tail of the current queue
921 * before proceeding further
922 */
923 struct ipq *q = TAILQ_LAST(head, ipqhead);
924 if (q == NULL) { /* gak */
925 for (i = 0; i < IPREASS_NHASH; i++) {
926 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead);
927 if (r) {
928 IPSTAT_ADD(ips_fragtimeout,
929 r->ipq_nfrags);
930 ip_freef(&V_ipq[i], r);
931 break;
932 }
933 }
934 } else {
935 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags);
936 ip_freef(head, q);
937 }
938 }
939
940found:
941 /*
942 * Adjust ip_len to not reflect header,
943 * convert offset of this to bytes.
944 */
945 ip->ip_len -= hlen;
946 if (ip->ip_off & IP_MF) {
947 /*
948 * Make sure that fragments have a data length
949 * that's a non-zero multiple of 8 bytes.
950 */
951 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
952 IPSTAT_INC(ips_toosmall); /* XXX */
953 goto dropfrag;
954 }
955 m->m_flags |= M_FRAG;
956 } else
957 m->m_flags &= ~M_FRAG;
958 ip->ip_off <<= 3;
959
960
961 /*
962 * Attempt reassembly; if it succeeds, proceed.
963 * ip_reass() will return a different mbuf.
964 */
965 IPSTAT_INC(ips_fragments);
966 m->m_pkthdr.header = ip;
967
968 /* Previous ip_reass() started here. */
969 /*
970 * Presence of header sizes in mbufs
971 * would confuse code below.
972 */
973 m->m_data += hlen;
974 m->m_len -= hlen;
975
976 /*
977 * If first fragment to arrive, create a reassembly queue.
978 */
979 if (fp == NULL) {
980 fp = uma_zalloc(V_ipq_zone, M_NOWAIT);
981 if (fp == NULL)
982 goto dropfrag;
983#ifdef MAC
984 if (mac_ipq_init(fp, M_NOWAIT) != 0) {
985 uma_zfree(V_ipq_zone, fp);
986 fp = NULL;
987 goto dropfrag;
988 }
989 mac_ipq_create(m, fp);
990#endif
991 TAILQ_INSERT_HEAD(head, fp, ipq_list);
992 V_nipq++;
993 fp->ipq_nfrags = 1;
994 fp->ipq_ttl = IPFRAGTTL;
995 fp->ipq_p = ip->ip_p;
996 fp->ipq_id = ip->ip_id;
997 fp->ipq_src = ip->ip_src;
998 fp->ipq_dst = ip->ip_dst;
999 fp->ipq_frags = m;
1000 m->m_nextpkt = NULL;
1001 goto done;
1002 } else {
1003 fp->ipq_nfrags++;
1004#ifdef MAC
1005 mac_ipq_update(m, fp);
1006#endif
1007 }
1008
1009#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
1010
1011 /*
1012 * Handle ECN by comparing this segment with the first one;
1013 * if CE is set, do not lose CE.
1014 * drop if CE and not-ECT are mixed for the same packet.
1015 */
1016 ecn = ip->ip_tos & IPTOS_ECN_MASK;
1017 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
1018 if (ecn == IPTOS_ECN_CE) {
1019 if (ecn0 == IPTOS_ECN_NOTECT)
1020 goto dropfrag;
1021 if (ecn0 != IPTOS_ECN_CE)
1022 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
1023 }
1024 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
1025 goto dropfrag;
1026
1027 /*
1028 * Find a segment which begins after this one does.
1029 */
1030 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
1031 if (GETIP(q)->ip_off > ip->ip_off)
1032 break;
1033
1034 /*
1035 * If there is a preceding segment, it may provide some of
1036 * our data already. If so, drop the data from the incoming
1037 * segment. If it provides all of our data, drop us, otherwise
1038 * stick new segment in the proper place.
1039 *
1040 * If some of the data is dropped from the the preceding
1041 * segment, then it's checksum is invalidated.
1042 */
1043 if (p) {
1044 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
1045 if (i > 0) {
1046 if (i >= ip->ip_len)
1047 goto dropfrag;
1048 m_adj(m, i);
1049 m->m_pkthdr.csum_flags = 0;
1050 ip->ip_off += i;
1051 ip->ip_len -= i;
1052 }
1053 m->m_nextpkt = p->m_nextpkt;
1054 p->m_nextpkt = m;
1055 } else {
1056 m->m_nextpkt = fp->ipq_frags;
1057 fp->ipq_frags = m;
1058 }
1059
1060 /*
1061 * While we overlap succeeding segments trim them or,
1062 * if they are completely covered, dequeue them.
1063 */
1064 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
1065 q = nq) {
1066 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
1067 if (i < GETIP(q)->ip_len) {
1068 GETIP(q)->ip_len -= i;
1069 GETIP(q)->ip_off += i;
1070 m_adj(q, i);
1071 q->m_pkthdr.csum_flags = 0;
1072 break;
1073 }
1074 nq = q->m_nextpkt;
1075 m->m_nextpkt = nq;
1076 IPSTAT_INC(ips_fragdropped);
1077 fp->ipq_nfrags--;
1078 m_freem(q);
1079 }
1080
1081 /*
1082 * Check for complete reassembly and perform frag per packet
1083 * limiting.
1084 *
1085 * Frag limiting is performed here so that the nth frag has
1086 * a chance to complete the packet before we drop the packet.
1087 * As a result, n+1 frags are actually allowed per packet, but
1088 * only n will ever be stored. (n = maxfragsperpacket.)
1089 *
1090 */
1091 next = 0;
1092 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1093 if (GETIP(q)->ip_off != next) {
1094 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1095 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1096 ip_freef(head, fp);
1097 }
1098 goto done;
1099 }
1100 next += GETIP(q)->ip_len;
1101 }
1102 /* Make sure the last packet didn't have the IP_MF flag */
1103 if (p->m_flags & M_FRAG) {
1104 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1105 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1106 ip_freef(head, fp);
1107 }
1108 goto done;
1109 }
1110
1111 /*
1112 * Reassembly is complete. Make sure the packet is a sane size.
1113 */
1114 q = fp->ipq_frags;
1115 ip = GETIP(q);
1116 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
1117 IPSTAT_INC(ips_toolong);
1118 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1119 ip_freef(head, fp);
1120 goto done;
1121 }
1122
1123 /*
1124 * Concatenate fragments.
1125 */
1126 m = q;
1127 t = m->m_next;
1128 m->m_next = NULL;
1129 m_cat(m, t);
1130 nq = q->m_nextpkt;
1131 q->m_nextpkt = NULL;
1132 for (q = nq; q != NULL; q = nq) {
1133 nq = q->m_nextpkt;
1134 q->m_nextpkt = NULL;
1135 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1136 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1137 m_cat(m, q);
1138 }
1139 /*
1140 * In order to do checksumming faster we do 'end-around carry' here
1141 * (and not in for{} loop), though it implies we are not going to
1142 * reassemble more than 64k fragments.
1143 */
1144 m->m_pkthdr.csum_data =
1145 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16);
1146#ifdef MAC
1147 mac_ipq_reassemble(fp, m);
1148 mac_ipq_destroy(fp);
1149#endif
1150
1151 /*
1152 * Create header for new ip packet by modifying header of first
1153 * packet; dequeue and discard fragment reassembly header.
1154 * Make header visible.
1155 */
1156 ip->ip_len = (ip->ip_hl << 2) + next;
1157 ip->ip_src = fp->ipq_src;
1158 ip->ip_dst = fp->ipq_dst;
1159 TAILQ_REMOVE(head, fp, ipq_list);
1160 V_nipq--;
1161 uma_zfree(V_ipq_zone, fp);
1162 m->m_len += (ip->ip_hl << 2);
1163 m->m_data -= (ip->ip_hl << 2);
1164 /* some debugging cruft by sklower, below, will go away soon */
1165 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
1166 m_fixhdr(m);
1167 IPSTAT_INC(ips_reassembled);
1168 IPQ_UNLOCK();
1169 return (m);
1170
1171dropfrag:
1172 IPSTAT_INC(ips_fragdropped);
1173 if (fp != NULL)
1174 fp->ipq_nfrags--;
1175 m_freem(m);
1176done:
1177 IPQ_UNLOCK();
1178 return (NULL);
1179
1180#undef GETIP
1181}
1182
1183/*
1184 * Free a fragment reassembly header and all
1185 * associated datagrams.
1186 */
1187static void
1188ip_freef(struct ipqhead *fhp, struct ipq *fp)
1189{
1190 struct mbuf *q;
1191
1192 IPQ_LOCK_ASSERT();
1193
1194 while (fp->ipq_frags) {
1195 q = fp->ipq_frags;
1196 fp->ipq_frags = q->m_nextpkt;
1197 m_freem(q);
1198 }
1199 TAILQ_REMOVE(fhp, fp, ipq_list);
1200 uma_zfree(V_ipq_zone, fp);
1201 V_nipq--;
1202}
1203
1204/*
1205 * IP timer processing;
1206 * if a timer expires on a reassembly
1207 * queue, discard it.
1208 */
1209void
1210ip_slowtimo(void)
1211{
1212 VNET_ITERATOR_DECL(vnet_iter);
1213 struct ipq *fp;
1214 int i;
1215
1216 VNET_LIST_RLOCK_NOSLEEP();
1217 IPQ_LOCK();
1218 VNET_FOREACH(vnet_iter) {
1219 CURVNET_SET(vnet_iter);
1220 for (i = 0; i < IPREASS_NHASH; i++) {
1221 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) {
1222 struct ipq *fpp;
1223
1224 fpp = fp;
1225 fp = TAILQ_NEXT(fp, ipq_list);
1226 if(--fpp->ipq_ttl == 0) {
1227 IPSTAT_ADD(ips_fragtimeout,
1228 fpp->ipq_nfrags);
1229 ip_freef(&V_ipq[i], fpp);
1230 }
1231 }
1232 }
1233 /*
1234 * If we are over the maximum number of fragments
1235 * (due to the limit being lowered), drain off
1236 * enough to get down to the new limit.
1237 */
1238 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) {
1239 for (i = 0; i < IPREASS_NHASH; i++) {
1240 while (V_nipq > V_maxnipq &&
1241 !TAILQ_EMPTY(&V_ipq[i])) {
1242 IPSTAT_ADD(ips_fragdropped,
1243 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1244 ip_freef(&V_ipq[i],
1245 TAILQ_FIRST(&V_ipq[i]));
1246 }
1247 }
1248 }
1249 CURVNET_RESTORE();
1250 }
1251 IPQ_UNLOCK();
1252 VNET_LIST_RUNLOCK_NOSLEEP();
1253}
1254
1255/*
1256 * Drain off all datagram fragments.
1257 */
1258static void
1259ip_drain_locked(void)
1260{
1261 int i;
1262
1263 IPQ_LOCK_ASSERT();
1264
1265 for (i = 0; i < IPREASS_NHASH; i++) {
1266 while(!TAILQ_EMPTY(&V_ipq[i])) {
1267 IPSTAT_ADD(ips_fragdropped,
1268 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1269 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i]));
1270 }
1271 }
1272}
1273
1274void
1275ip_drain(void)
1276{
1277 VNET_ITERATOR_DECL(vnet_iter);
1278
1279 VNET_LIST_RLOCK_NOSLEEP();
1280 IPQ_LOCK();
1281 VNET_FOREACH(vnet_iter) {
1282 CURVNET_SET(vnet_iter);
1283 ip_drain_locked();
1284 CURVNET_RESTORE();
1285 }
1286 IPQ_UNLOCK();
1287 VNET_LIST_RUNLOCK_NOSLEEP();
1288 in_rtqdrain();
1289}
1290
1291/*
1292 * The protocol to be inserted into ip_protox[] must be already registered
1293 * in inetsw[], either statically or through pf_proto_register().
1294 */
1295int
1296ipproto_register(u_char ipproto)
1297{
1298 struct protosw *pr;
1299
1300 /* Sanity checks. */
1301 if (ipproto == 0)
1302 return (EPROTONOSUPPORT);
1303
1304 /*
1305 * The protocol slot must not be occupied by another protocol
1306 * already. An index pointing to IPPROTO_RAW is unused.
1307 */
1308 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1309 if (pr == NULL)
1310 return (EPFNOSUPPORT);
1311 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
1312 return (EEXIST);
1313
1314 /* Find the protocol position in inetsw[] and set the index. */
1315 for (pr = inetdomain.dom_protosw;
1316 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
1317 if (pr->pr_domain->dom_family == PF_INET &&
1318 pr->pr_protocol && pr->pr_protocol == ipproto) {
1319 /* Be careful to only index valid IP protocols. */
1320 if (pr->pr_protocol < IPPROTO_MAX) {
1321 ip_protox[pr->pr_protocol] = pr - inetsw;
1322 return (0);
1323 } else
1324 return (EINVAL);
1325 }
1326 }
1327 return (EPROTONOSUPPORT);
1328}
1329
1330int
1331ipproto_unregister(u_char ipproto)
1332{
1333 struct protosw *pr;
1334
1335 /* Sanity checks. */
1336 if (ipproto == 0)
1337 return (EPROTONOSUPPORT);
1338
1339 /* Check if the protocol was indeed registered. */
1340 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1341 if (pr == NULL)
1342 return (EPFNOSUPPORT);
1343 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
1344 return (ENOENT);
1345
1346 /* Reset the protocol slot to IPPROTO_RAW. */
1347 ip_protox[ipproto] = pr - inetsw;
1348 return (0);
1349}
1350
1351/*
1352 * Given address of next destination (final or next hop), return (referenced)
1353 * internet address info of interface to be used to get there.
1354 */
1355struct in_ifaddr *
1356ip_rtaddr(struct in_addr dst, u_int fibnum)
1357{
1358 struct route sro;
1359 struct sockaddr_in *sin;
1360 struct in_ifaddr *ia;
1361
1362 bzero(&sro, sizeof(sro));
1363 sin = (struct sockaddr_in *)&sro.ro_dst;
1364 sin->sin_family = AF_INET;
1365 sin->sin_len = sizeof(*sin);
1366 sin->sin_addr = dst;
1367 in_rtalloc_ign(&sro, 0, fibnum);
1368
1369 if (sro.ro_rt == NULL)
1370 return (NULL);
1371
1372 ia = ifatoia(sro.ro_rt->rt_ifa);
1373 ifa_ref(&ia->ia_ifa);
1374 RTFREE(sro.ro_rt);
1375 return (ia);
1376}
1377
1378u_char inetctlerrmap[PRC_NCMDS] = {
1379 0, 0, 0, 0,
1380 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1381 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1382 EMSGSIZE, EHOSTUNREACH, 0, 0,
1383 0, 0, EHOSTUNREACH, 0,
1384 ENOPROTOOPT, ECONNREFUSED
1385};
1386
1387/*
1388 * Forward a packet. If some error occurs return the sender
1389 * an icmp packet. Note we can't always generate a meaningful
1390 * icmp message because icmp doesn't have a large enough repertoire
1391 * of codes and types.
1392 *
1393 * If not forwarding, just drop the packet. This could be confusing
1394 * if ipforwarding was zero but some routing protocol was advancing
1395 * us as a gateway to somewhere. However, we must let the routing
1396 * protocol deal with that.
1397 *
1398 * The srcrt parameter indicates whether the packet is being forwarded
1399 * via a source route.
1400 */
1401void
1402ip_forward(struct mbuf *m, int srcrt)
1403{
1404 struct ip *ip = mtod(m, struct ip *);
1405 struct in_ifaddr *ia;
1406 struct mbuf *mcopy;
1407 struct in_addr dest;
1408 struct route ro;
1409 int error, type = 0, code = 0, mtu = 0;
1410
1411 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1412 IPSTAT_INC(ips_cantforward);
1413 m_freem(m);
1414 return;
1415 }
1416#ifdef IPSTEALTH
1417 if (!V_ipstealth) {
1418#endif
1419 if (ip->ip_ttl <= IPTTLDEC) {
1420 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
1421 0, 0);
1422 return;
1423 }
1424#ifdef IPSTEALTH
1425 }
1426#endif
1427
1428 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
1429#ifndef IPSEC
1430 /*
1431 * 'ia' may be NULL if there is no route for this destination.
1432 * In case of IPsec, Don't discard it just yet, but pass it to
1433 * ip_output in case of outgoing IPsec policy.
1434 */
1435 if (!srcrt && ia == NULL) {
1436 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
1437 return;
1438 }
1439#endif
1440
1441 /*
1442 * Save the IP header and at most 8 bytes of the payload,
1443 * in case we need to generate an ICMP message to the src.
1444 *
1445 * XXX this can be optimized a lot by saving the data in a local
1446 * buffer on the stack (72 bytes at most), and only allocating the
1447 * mbuf if really necessary. The vast majority of the packets
1448 * are forwarded without having to send an ICMP back (either
1449 * because unnecessary, or because rate limited), so we are
1450 * really we are wasting a lot of work here.
1451 *
1452 * We don't use m_copy() because it might return a reference
1453 * to a shared cluster. Both this function and ip_output()
1454 * assume exclusive access to the IP header in `m', so any
1455 * data in a cluster may change before we reach icmp_error().
1456 */
1457 MGETHDR(mcopy, M_DONTWAIT, m->m_type);
1458 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) {
1459 /*
1460 * It's probably ok if the pkthdr dup fails (because
1461 * the deep copy of the tag chain failed), but for now
1462 * be conservative and just discard the copy since
1463 * code below may some day want the tags.
1464 */
1465 m_free(mcopy);
1466 mcopy = NULL;
1467 }
1468 if (mcopy != NULL) {
1469 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy));
1470 mcopy->m_pkthdr.len = mcopy->m_len;
1471 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1472 }
1473
1474#ifdef IPSTEALTH
1475 if (!V_ipstealth) {
1476#endif
1477 ip->ip_ttl -= IPTTLDEC;
1478#ifdef IPSTEALTH
1479 }
1480#endif
1481
1482 /*
1483 * If forwarding packet using same interface that it came in on,
1484 * perhaps should send a redirect to sender to shortcut a hop.
1485 * Only send redirect if source is sending directly to us,
1486 * and if packet was not source routed (or has any options).
1487 * Also, don't send redirect if forwarding using a default route
1488 * or a route modified by a redirect.
1489 */
1490 dest.s_addr = 0;
1491 if (!srcrt && V_ipsendredirects &&
1492 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
1493 struct sockaddr_in *sin;
1494 struct rtentry *rt;
1495
1496 bzero(&ro, sizeof(ro));
1497 sin = (struct sockaddr_in *)&ro.ro_dst;
1498 sin->sin_family = AF_INET;
1499 sin->sin_len = sizeof(*sin);
1500 sin->sin_addr = ip->ip_dst;
1501 in_rtalloc_ign(&ro, 0, M_GETFIB(m));
1502
1503 rt = ro.ro_rt;
1504
1505 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1506 satosin(rt_key(rt))->sin_addr.s_addr != 0) {
1507#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1508 u_long src = ntohl(ip->ip_src.s_addr);
1509
1510 if (RTA(rt) &&
1511 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1512 if (rt->rt_flags & RTF_GATEWAY)
1513 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
1514 else
1515 dest.s_addr = ip->ip_dst.s_addr;
1516 /* Router requirements says to only send host redirects */
1517 type = ICMP_REDIRECT;
1518 code = ICMP_REDIRECT_HOST;
1519 }
1520 }
1521 if (rt)
1522 RTFREE(rt);
1523 }
1524
1525 /*
1526 * Try to cache the route MTU from ip_output so we can consider it for
1527 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191.
1528 */
1529 bzero(&ro, sizeof(ro));
1530
1531 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
1532
1533 if (error == EMSGSIZE && ro.ro_rt)
1534 mtu = ro.ro_rt->rt_rmx.rmx_mtu;
1535 if (ro.ro_rt)
1536 RTFREE(ro.ro_rt);
1537
1538 if (error)
1539 IPSTAT_INC(ips_cantforward);
1540 else {
1541 IPSTAT_INC(ips_forward);
1542 if (type)
1543 IPSTAT_INC(ips_redirectsent);
1544 else {
1545 if (mcopy)
1546 m_freem(mcopy);
1547 if (ia != NULL)
1548 ifa_free(&ia->ia_ifa);
1549 return;
1550 }
1551 }
1552 if (mcopy == NULL) {
1553 if (ia != NULL)
1554 ifa_free(&ia->ia_ifa);
1555 return;
1556 }
1557
1558 switch (error) {
1559
1560 case 0: /* forwarded, but need redirect */
1561 /* type, code set above */
1562 break;
1563
1564 case ENETUNREACH:
1565 case EHOSTUNREACH:
1566 case ENETDOWN:
1567 case EHOSTDOWN:
1568 default:
1569 type = ICMP_UNREACH;
1570 code = ICMP_UNREACH_HOST;
1571 break;
1572
1573 case EMSGSIZE:
1574 type = ICMP_UNREACH;
1575 code = ICMP_UNREACH_NEEDFRAG;
1576
1577#ifdef IPSEC
1578 /*
1579 * If IPsec is configured for this path,
1580 * override any possibly mtu value set by ip_output.
1581 */
1582 mtu = ip_ipsec_mtu(mcopy, mtu);
1583#endif /* IPSEC */
1584 /*
1585 * If the MTU was set before make sure we are below the
1586 * interface MTU.
1587 * If the MTU wasn't set before use the interface mtu or
1588 * fall back to the next smaller mtu step compared to the
1589 * current packet size.
1590 */
1591 if (mtu != 0) {
1592 if (ia != NULL)
1593 mtu = min(mtu, ia->ia_ifp->if_mtu);
1594 } else {
1595 if (ia != NULL)
1596 mtu = ia->ia_ifp->if_mtu;
1597 else
1598 mtu = ip_next_mtu(ip->ip_len, 0);
1599 }
1600 IPSTAT_INC(ips_cantfrag);
1601 break;
1602
1603 case ENOBUFS:
1604 /*
1605 * A router should not generate ICMP_SOURCEQUENCH as
1606 * required in RFC1812 Requirements for IP Version 4 Routers.
1607 * Source quench could be a big problem under DoS attacks,
1608 * or if the underlying interface is rate-limited.
1609 * Those who need source quench packets may re-enable them
1610 * via the net.inet.ip.sendsourcequench sysctl.
1611 */
1612 if (V_ip_sendsourcequench == 0) {
1613 m_freem(mcopy);
1614 if (ia != NULL)
1615 ifa_free(&ia->ia_ifa);
1616 return;
1617 } else {
1618 type = ICMP_SOURCEQUENCH;
1619 code = 0;
1620 }
1621 break;
1622
1623 case EACCES: /* ipfw denied packet */
1624 m_freem(mcopy);
1625 if (ia != NULL)
1626 ifa_free(&ia->ia_ifa);
1627 return;
1628 }
1629 if (ia != NULL)
1630 ifa_free(&ia->ia_ifa);
1631 icmp_error(mcopy, type, code, dest.s_addr, mtu);
1632}
1633
1634void
1635ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1636 struct mbuf *m)
1637{
1638
1639 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) {
1640 struct bintime bt;
1641
1642 bintime(&bt);
1643 if (inp->inp_socket->so_options & SO_BINTIME) {
1644 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt),
1645 SCM_BINTIME, SOL_SOCKET);
1646 if (*mp)
1647 mp = &(*mp)->m_next;
1648 }
1649 if (inp->inp_socket->so_options & SO_TIMESTAMP) {
1650 struct timeval tv;
1651
1652 bintime2timeval(&bt, &tv);
1653 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1654 SCM_TIMESTAMP, SOL_SOCKET);
1655 if (*mp)
1656 mp = &(*mp)->m_next;
1657 }
1658 }
1659 if (inp->inp_flags & INP_RECVDSTADDR) {
1660 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
1661 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1662 if (*mp)
1663 mp = &(*mp)->m_next;
1664 }
1665 if (inp->inp_flags & INP_RECVTTL) {
1666 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl,
1667 sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
1668 if (*mp)
1669 mp = &(*mp)->m_next;
1670 }
1671#ifdef notyet
1672 /* XXX
1673 * Moving these out of udp_input() made them even more broken
1674 * than they already were.
1675 */
1676 /* options were tossed already */
1677 if (inp->inp_flags & INP_RECVOPTS) {
1678 *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
1679 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
1680 if (*mp)
1681 mp = &(*mp)->m_next;
1682 }
1683 /* ip_srcroute doesn't do what we want here, need to fix */
1684 if (inp->inp_flags & INP_RECVRETOPTS) {
1685 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m),
1686 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
1687 if (*mp)
1688 mp = &(*mp)->m_next;
1689 }
1690#endif
1691 if (inp->inp_flags & INP_RECVIF) {
1692 struct ifnet *ifp;
1693 struct sdlbuf {
1694 struct sockaddr_dl sdl;
1695 u_char pad[32];
1696 } sdlbuf;
1697 struct sockaddr_dl *sdp;
1698 struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
1699
1700 if (((ifp = m->m_pkthdr.rcvif))
1701 && ( ifp->if_index && (ifp->if_index <= V_if_index))) {
1702 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
1703 /*
1704 * Change our mind and don't try copy.
1705 */
1706 if ((sdp->sdl_family != AF_LINK)
1707 || (sdp->sdl_len > sizeof(sdlbuf))) {
1708 goto makedummy;
1709 }
1710 bcopy(sdp, sdl2, sdp->sdl_len);
1711 } else {
1712makedummy:
1713 sdl2->sdl_len
1714 = offsetof(struct sockaddr_dl, sdl_data[0]);
1715 sdl2->sdl_family = AF_LINK;
1716 sdl2->sdl_index = 0;
1717 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
1718 }
1719 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
1720 IP_RECVIF, IPPROTO_IP);
1721 if (*mp)
1722 mp = &(*mp)->m_next;
1723 }
1724}
1725
1726/*
1727 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
1728 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
1729 * locking. This code remains in ip_input.c as ip_mroute.c is optionally
1730 * compiled.
1731 */
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