34
35#include "opt_bootp.h"
36#include "opt_ipfw.h"
37#include "opt_ipstealth.h"
38#include "opt_ipsec.h"
39#include "opt_route.h"
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/mbuf.h>
44#include <sys/malloc.h>
45#include <sys/domain.h>
46#include <sys/protosw.h>
47#include <sys/socket.h>
48#include <sys/time.h>
49#include <sys/kernel.h>
50#include <sys/lock.h>
51#include <sys/rwlock.h>
52#include <sys/sdt.h>
53#include <sys/syslog.h>
54#include <sys/sysctl.h>
55
56#include <net/pfil.h>
57#include <net/if.h>
58#include <net/if_types.h>
59#include <net/if_var.h>
60#include <net/if_dl.h>
61#include <net/route.h>
62#include <net/netisr.h>
63#include <net/vnet.h>
64
65#include <netinet/in.h>
66#include <netinet/in_kdtrace.h>
67#include <netinet/in_systm.h>
68#include <netinet/in_var.h>
69#include <netinet/ip.h>
70#include <netinet/in_pcb.h>
71#include <netinet/ip_var.h>
72#include <netinet/ip_fw.h>
73#include <netinet/ip_icmp.h>
74#include <netinet/ip_options.h>
75#include <machine/in_cksum.h>
76#include <netinet/ip_carp.h>
77#ifdef IPSEC
78#include <netinet/ip_ipsec.h>
79#endif /* IPSEC */
80
81#include <sys/socketvar.h>
82
83#include <security/mac/mac_framework.h>
84
85#ifdef CTASSERT
86CTASSERT(sizeof(struct ip) == 20);
87#endif
88
89struct rwlock in_ifaddr_lock;
90RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock");
91
92VNET_DEFINE(int, rsvp_on);
93
94VNET_DEFINE(int, ipforwarding);
95SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
96 &VNET_NAME(ipforwarding), 0,
97 "Enable IP forwarding between interfaces");
98
99static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */
100#define V_ipsendredirects VNET(ipsendredirects)
101SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
102 &VNET_NAME(ipsendredirects), 0,
103 "Enable sending IP redirects");
104
105static VNET_DEFINE(int, ip_keepfaith);
106#define V_ip_keepfaith VNET(ip_keepfaith)
107SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
108 &VNET_NAME(ip_keepfaith), 0,
109 "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
110
111static VNET_DEFINE(int, ip_sendsourcequench);
112#define V_ip_sendsourcequench VNET(ip_sendsourcequench)
113SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
114 &VNET_NAME(ip_sendsourcequench), 0,
115 "Enable the transmission of source quench packets");
116
117VNET_DEFINE(int, ip_do_randomid);
118SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
119 &VNET_NAME(ip_do_randomid), 0,
120 "Assign random ip_id values");
121
122/*
123 * XXX - Setting ip_checkinterface mostly implements the receive side of
124 * the Strong ES model described in RFC 1122, but since the routing table
125 * and transmit implementation do not implement the Strong ES model,
126 * setting this to 1 results in an odd hybrid.
127 *
128 * XXX - ip_checkinterface currently must be disabled if you use ipnat
129 * to translate the destination address to another local interface.
130 *
131 * XXX - ip_checkinterface must be disabled if you add IP aliases
132 * to the loopback interface instead of the interface where the
133 * packets for those addresses are received.
134 */
135static VNET_DEFINE(int, ip_checkinterface);
136#define V_ip_checkinterface VNET(ip_checkinterface)
137SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
138 &VNET_NAME(ip_checkinterface), 0,
139 "Verify packet arrives on correct interface");
140
141VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */
142
143static struct netisr_handler ip_nh = {
144 .nh_name = "ip",
145 .nh_handler = ip_input,
146 .nh_proto = NETISR_IP,
147 .nh_policy = NETISR_POLICY_FLOW,
148};
149
150extern struct domain inetdomain;
151extern struct protosw inetsw[];
152u_char ip_protox[IPPROTO_MAX];
153VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */
154VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */
155VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */
156
157static VNET_DEFINE(uma_zone_t, ipq_zone);
158static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]);
159static struct mtx ipqlock;
160
161#define V_ipq_zone VNET(ipq_zone)
162#define V_ipq VNET(ipq)
163
164#define IPQ_LOCK() mtx_lock(&ipqlock)
165#define IPQ_UNLOCK() mtx_unlock(&ipqlock)
166#define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
167#define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
168
169static void maxnipq_update(void);
170static void ipq_zone_change(void *);
171static void ip_drain_locked(void);
172
173static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */
174static VNET_DEFINE(int, nipq); /* Total # of reass queues */
175#define V_maxnipq VNET(maxnipq)
176#define V_nipq VNET(nipq)
177SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD,
178 &VNET_NAME(nipq), 0,
179 "Current number of IPv4 fragment reassembly queue entries");
180
181static VNET_DEFINE(int, maxfragsperpacket);
182#define V_maxfragsperpacket VNET(maxfragsperpacket)
183SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
184 &VNET_NAME(maxfragsperpacket), 0,
185 "Maximum number of IPv4 fragments allowed per packet");
186
187#ifdef IPCTL_DEFMTU
188SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
189 &ip_mtu, 0, "Default MTU");
190#endif
191
192#ifdef IPSTEALTH
193VNET_DEFINE(int, ipstealth);
194SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
195 &VNET_NAME(ipstealth), 0,
196 "IP stealth mode, no TTL decrementation on forwarding");
197#endif
198
199static void ip_freef(struct ipqhead *, struct ipq *);
200
201/*
202 * IP statistics are stored in the "array" of counter(9)s.
203 */
204VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat);
205VNET_PCPUSTAT_SYSINIT(ipstat);
206SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat,
207 "IP statistics (struct ipstat, netinet/ip_var.h)");
208
209#ifdef VIMAGE
210VNET_PCPUSTAT_SYSUNINIT(ipstat);
211#endif /* VIMAGE */
212
213/*
214 * Kernel module interface for updating ipstat. The argument is an index
215 * into ipstat treated as an array.
216 */
217void
218kmod_ipstat_inc(int statnum)
219{
220
221 counter_u64_add(VNET(ipstat)[statnum], 1);
222}
223
224void
225kmod_ipstat_dec(int statnum)
226{
227
228 counter_u64_add(VNET(ipstat)[statnum], -1);
229}
230
231static int
232sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
233{
234 int error, qlimit;
235
236 netisr_getqlimit(&ip_nh, &qlimit);
237 error = sysctl_handle_int(oidp, &qlimit, 0, req);
238 if (error || !req->newptr)
239 return (error);
240 if (qlimit < 1)
241 return (EINVAL);
242 return (netisr_setqlimit(&ip_nh, qlimit));
243}
244SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
245 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I",
246 "Maximum size of the IP input queue");
247
248static int
249sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
250{
251 u_int64_t qdrops_long;
252 int error, qdrops;
253
254 netisr_getqdrops(&ip_nh, &qdrops_long);
255 qdrops = qdrops_long;
256 error = sysctl_handle_int(oidp, &qdrops, 0, req);
257 if (error || !req->newptr)
258 return (error);
259 if (qdrops != 0)
260 return (EINVAL);
261 netisr_clearqdrops(&ip_nh);
262 return (0);
263}
264
265SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
266 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I",
267 "Number of packets dropped from the IP input queue");
268
269/*
270 * IP initialization: fill in IP protocol switch table.
271 * All protocols not implemented in kernel go to raw IP protocol handler.
272 */
273void
274ip_init(void)
275{
276 struct protosw *pr;
277 int i;
278
279 V_ip_id = time_second & 0xffff;
280
281 TAILQ_INIT(&V_in_ifaddrhead);
282 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
283
284 /* Initialize IP reassembly queue. */
285 for (i = 0; i < IPREASS_NHASH; i++)
286 TAILQ_INIT(&V_ipq[i]);
287 V_maxnipq = nmbclusters / 32;
288 V_maxfragsperpacket = 16;
289 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
290 NULL, UMA_ALIGN_PTR, 0);
291 maxnipq_update();
292
293 /* Initialize packet filter hooks. */
294 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF;
295 V_inet_pfil_hook.ph_af = AF_INET;
296 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0)
297 printf("%s: WARNING: unable to register pfil hook, "
298 "error %d\n", __func__, i);
299
300 /* Skip initialization of globals for non-default instances. */
301 if (!IS_DEFAULT_VNET(curvnet))
302 return;
303
304 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
305 if (pr == NULL)
306 panic("ip_init: PF_INET not found");
307
308 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
309 for (i = 0; i < IPPROTO_MAX; i++)
310 ip_protox[i] = pr - inetsw;
311 /*
312 * Cycle through IP protocols and put them into the appropriate place
313 * in ip_protox[].
314 */
315 for (pr = inetdomain.dom_protosw;
316 pr < inetdomain.dom_protoswNPROTOSW; pr++)
317 if (pr->pr_domain->dom_family == PF_INET &&
318 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
319 /* Be careful to only index valid IP protocols. */
320 if (pr->pr_protocol < IPPROTO_MAX)
321 ip_protox[pr->pr_protocol] = pr - inetsw;
322 }
323
324 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change,
325 NULL, EVENTHANDLER_PRI_ANY);
326
327 /* Initialize various other remaining things. */
328 IPQ_LOCK_INIT();
329 netisr_register(&ip_nh);
330}
331
332#ifdef VIMAGE
333void
334ip_destroy(void)
335{
336 int i;
337
338 if ((i = pfil_head_unregister(&V_inet_pfil_hook)) != 0)
339 printf("%s: WARNING: unable to unregister pfil hook, "
340 "error %d\n", __func__, i);
341
342 /* Cleanup in_ifaddr hash table; should be empty. */
343 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
344
345 IPQ_LOCK();
346 ip_drain_locked();
347 IPQ_UNLOCK();
348
349 uma_zdestroy(V_ipq_zone);
350}
351#endif
352
353/*
354 * Ip input routine. Checksum and byte swap header. If fragmented
355 * try to reassemble. Process options. Pass to next level.
356 */
357void
358ip_input(struct mbuf *m)
359{
360 struct ip *ip = NULL;
361 struct in_ifaddr *ia = NULL;
362 struct ifaddr *ifa;
363 struct ifnet *ifp;
364 int checkif, hlen = 0;
365 uint16_t sum, ip_len;
366 int dchg = 0; /* dest changed after fw */
367 struct in_addr odst; /* original dst address */
368
369 M_ASSERTPKTHDR(m);
370
371 if (m->m_flags & M_FASTFWD_OURS) {
372 m->m_flags &= ~M_FASTFWD_OURS;
373 /* Set up some basics that will be used later. */
374 ip = mtod(m, struct ip *);
375 hlen = ip->ip_hl << 2;
376 ip_len = ntohs(ip->ip_len);
377 goto ours;
378 }
379
380 IPSTAT_INC(ips_total);
381
382 if (m->m_pkthdr.len < sizeof(struct ip))
383 goto tooshort;
384
385 if (m->m_len < sizeof (struct ip) &&
386 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
387 IPSTAT_INC(ips_toosmall);
388 return;
389 }
390 ip = mtod(m, struct ip *);
391
392 if (ip->ip_v != IPVERSION) {
393 IPSTAT_INC(ips_badvers);
394 goto bad;
395 }
396
397 hlen = ip->ip_hl << 2;
398 if (hlen < sizeof(struct ip)) { /* minimum header length */
399 IPSTAT_INC(ips_badhlen);
400 goto bad;
401 }
402 if (hlen > m->m_len) {
403 if ((m = m_pullup(m, hlen)) == NULL) {
404 IPSTAT_INC(ips_badhlen);
405 return;
406 }
407 ip = mtod(m, struct ip *);
408 }
409
410 IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL);
411
412 /* 127/8 must not appear on wire - RFC1122 */
413 ifp = m->m_pkthdr.rcvif;
414 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
415 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
416 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
417 IPSTAT_INC(ips_badaddr);
418 goto bad;
419 }
420 }
421
422 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
423 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
424 } else {
425 if (hlen == sizeof(struct ip)) {
426 sum = in_cksum_hdr(ip);
427 } else {
428 sum = in_cksum(m, hlen);
429 }
430 }
431 if (sum) {
432 IPSTAT_INC(ips_badsum);
433 goto bad;
434 }
435
436#ifdef ALTQ
437 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
438 /* packet is dropped by traffic conditioner */
439 return;
440#endif
441
442 ip_len = ntohs(ip->ip_len);
443 if (ip_len < hlen) {
444 IPSTAT_INC(ips_badlen);
445 goto bad;
446 }
447
448 /*
449 * Check that the amount of data in the buffers
450 * is as at least much as the IP header would have us expect.
451 * Trim mbufs if longer than we expect.
452 * Drop packet if shorter than we expect.
453 */
454 if (m->m_pkthdr.len < ip_len) {
455tooshort:
456 IPSTAT_INC(ips_tooshort);
457 goto bad;
458 }
459 if (m->m_pkthdr.len > ip_len) {
460 if (m->m_len == m->m_pkthdr.len) {
461 m->m_len = ip_len;
462 m->m_pkthdr.len = ip_len;
463 } else
464 m_adj(m, ip_len - m->m_pkthdr.len);
465 }
466#ifdef IPSEC
467 /*
468 * Bypass packet filtering for packets previously handled by IPsec.
469 */
470 if (ip_ipsec_filtertunnel(m))
471 goto passin;
472#endif /* IPSEC */
473
474 /*
475 * Run through list of hooks for input packets.
476 *
477 * NB: Beware of the destination address changing (e.g.
478 * by NAT rewriting). When this happens, tell
479 * ip_forward to do the right thing.
480 */
481
482 /* Jump over all PFIL processing if hooks are not active. */
483 if (!PFIL_HOOKED(&V_inet_pfil_hook))
484 goto passin;
485
486 odst = ip->ip_dst;
487 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0)
488 return;
489 if (m == NULL) /* consumed by filter */
490 return;
491
492 ip = mtod(m, struct ip *);
493 dchg = (odst.s_addr != ip->ip_dst.s_addr);
494 ifp = m->m_pkthdr.rcvif;
495
496 if (m->m_flags & M_FASTFWD_OURS) {
497 m->m_flags &= ~M_FASTFWD_OURS;
498 goto ours;
499 }
500 if (m->m_flags & M_IP_NEXTHOP) {
501 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL);
502 if (dchg != 0) {
503 /*
504 * Directly ship the packet on. This allows
505 * forwarding packets originally destined to us
506 * to some other directly connected host.
507 */
508 ip_forward(m, 1);
509 return;
510 }
511 }
512passin:
513
514 /*
515 * Process options and, if not destined for us,
516 * ship it on. ip_dooptions returns 1 when an
517 * error was detected (causing an icmp message
518 * to be sent and the original packet to be freed).
519 */
520 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
521 return;
522
523 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
524 * matter if it is destined to another node, or whether it is
525 * a multicast one, RSVP wants it! and prevents it from being forwarded
526 * anywhere else. Also checks if the rsvp daemon is running before
527 * grabbing the packet.
528 */
529 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP)
530 goto ours;
531
532 /*
533 * Check our list of addresses, to see if the packet is for us.
534 * If we don't have any addresses, assume any unicast packet
535 * we receive might be for us (and let the upper layers deal
536 * with it).
537 */
538 if (TAILQ_EMPTY(&V_in_ifaddrhead) &&
539 (m->m_flags & (M_MCAST|M_BCAST)) == 0)
540 goto ours;
541
542 /*
543 * Enable a consistency check between the destination address
544 * and the arrival interface for a unicast packet (the RFC 1122
545 * strong ES model) if IP forwarding is disabled and the packet
546 * is not locally generated and the packet is not subject to
547 * 'ipfw fwd'.
548 *
549 * XXX - Checking also should be disabled if the destination
550 * address is ipnat'ed to a different interface.
551 *
552 * XXX - Checking is incompatible with IP aliases added
553 * to the loopback interface instead of the interface where
554 * the packets are received.
555 *
556 * XXX - This is the case for carp vhost IPs as well so we
557 * insert a workaround. If the packet got here, we already
558 * checked with carp_iamatch() and carp_forus().
559 */
560 checkif = V_ip_checkinterface && (V_ipforwarding == 0) &&
561 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
562 ifp->if_carp == NULL && (dchg == 0);
563
564 /*
565 * Check for exact addresses in the hash bucket.
566 */
567 /* IN_IFADDR_RLOCK(); */
568 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
569 /*
570 * If the address matches, verify that the packet
571 * arrived via the correct interface if checking is
572 * enabled.
573 */
574 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
575 (!checkif || ia->ia_ifp == ifp)) {
576 counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
577 counter_u64_add(ia->ia_ifa.ifa_ibytes,
578 m->m_pkthdr.len);
579 /* IN_IFADDR_RUNLOCK(); */
580 goto ours;
581 }
582 }
583 /* IN_IFADDR_RUNLOCK(); */
584
585 /*
586 * Check for broadcast addresses.
587 *
588 * Only accept broadcast packets that arrive via the matching
589 * interface. Reception of forwarded directed broadcasts would
590 * be handled via ip_forward() and ether_output() with the loopback
591 * into the stack for SIMPLEX interfaces handled by ether_output().
592 */
593 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
594 IF_ADDR_RLOCK(ifp);
595 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
596 if (ifa->ifa_addr->sa_family != AF_INET)
597 continue;
598 ia = ifatoia(ifa);
599 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
600 ip->ip_dst.s_addr) {
601 counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
602 counter_u64_add(ia->ia_ifa.ifa_ibytes,
603 m->m_pkthdr.len);
604 IF_ADDR_RUNLOCK(ifp);
605 goto ours;
606 }
607#ifdef BOOTP_COMPAT
608 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
609 counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
610 counter_u64_add(ia->ia_ifa.ifa_ibytes,
611 m->m_pkthdr.len);
612 IF_ADDR_RUNLOCK(ifp);
613 goto ours;
614 }
615#endif
616 }
617 IF_ADDR_RUNLOCK(ifp);
618 ia = NULL;
619 }
620 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */
621 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
622 IPSTAT_INC(ips_cantforward);
623 m_freem(m);
624 return;
625 }
626 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
627 if (V_ip_mrouter) {
628 /*
629 * If we are acting as a multicast router, all
630 * incoming multicast packets are passed to the
631 * kernel-level multicast forwarding function.
632 * The packet is returned (relatively) intact; if
633 * ip_mforward() returns a non-zero value, the packet
634 * must be discarded, else it may be accepted below.
635 */
636 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
637 IPSTAT_INC(ips_cantforward);
638 m_freem(m);
639 return;
640 }
641
642 /*
643 * The process-level routing daemon needs to receive
644 * all multicast IGMP packets, whether or not this
645 * host belongs to their destination groups.
646 */
647 if (ip->ip_p == IPPROTO_IGMP)
648 goto ours;
649 IPSTAT_INC(ips_forward);
650 }
651 /*
652 * Assume the packet is for us, to avoid prematurely taking
653 * a lock on the in_multi hash. Protocols must perform
654 * their own filtering and update statistics accordingly.
655 */
656 goto ours;
657 }
658 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
659 goto ours;
660 if (ip->ip_dst.s_addr == INADDR_ANY)
661 goto ours;
662
663 /*
664 * FAITH(Firewall Aided Internet Translator)
665 */
666 if (ifp && ifp->if_type == IFT_FAITH) {
667 if (V_ip_keepfaith) {
668 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
669 goto ours;
670 }
671 m_freem(m);
672 return;
673 }
674
675 /*
676 * Not for us; forward if possible and desirable.
677 */
678 if (V_ipforwarding == 0) {
679 IPSTAT_INC(ips_cantforward);
680 m_freem(m);
681 } else {
682#ifdef IPSEC
683 if (ip_ipsec_fwd(m))
684 goto bad;
685#endif /* IPSEC */
686 ip_forward(m, dchg);
687 }
688 return;
689
690ours:
691#ifdef IPSTEALTH
692 /*
693 * IPSTEALTH: Process non-routing options only
694 * if the packet is destined for us.
695 */
696 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1))
697 return;
698#endif /* IPSTEALTH */
699
700 /*
701 * Attempt reassembly; if it succeeds, proceed.
702 * ip_reass() will return a different mbuf.
703 */
704 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
705 m = ip_reass(m);
706 if (m == NULL)
707 return;
708 ip = mtod(m, struct ip *);
709 /* Get the header length of the reassembled packet */
710 hlen = ip->ip_hl << 2;
711 }
712
713#ifdef IPSEC
714 /*
715 * enforce IPsec policy checking if we are seeing last header.
716 * note that we do not visit this with protocols with pcb layer
717 * code - like udp/tcp/raw ip.
718 */
719 if (ip_ipsec_input(m))
720 goto bad;
721#endif /* IPSEC */
722
723 /*
724 * Switch out to protocol's input routine.
725 */
726 IPSTAT_INC(ips_delivered);
727
728 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
729 return;
730bad:
731 m_freem(m);
732}
733
734/*
735 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
736 * max has slightly different semantics than the sysctl, for historical
737 * reasons.
738 */
739static void
740maxnipq_update(void)
741{
742
743 /*
744 * -1 for unlimited allocation.
745 */
746 if (V_maxnipq < 0)
747 uma_zone_set_max(V_ipq_zone, 0);
748 /*
749 * Positive number for specific bound.
750 */
751 if (V_maxnipq > 0)
752 uma_zone_set_max(V_ipq_zone, V_maxnipq);
753 /*
754 * Zero specifies no further fragment queue allocation -- set the
755 * bound very low, but rely on implementation elsewhere to actually
756 * prevent allocation and reclaim current queues.
757 */
758 if (V_maxnipq == 0)
759 uma_zone_set_max(V_ipq_zone, 1);
760}
761
762static void
763ipq_zone_change(void *tag)
764{
765
766 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) {
767 V_maxnipq = nmbclusters / 32;
768 maxnipq_update();
769 }
770}
771
772static int
773sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
774{
775 int error, i;
776
777 i = V_maxnipq;
778 error = sysctl_handle_int(oidp, &i, 0, req);
779 if (error || !req->newptr)
780 return (error);
781
782 /*
783 * XXXRW: Might be a good idea to sanity check the argument and place
784 * an extreme upper bound.
785 */
786 if (i < -1)
787 return (EINVAL);
788 V_maxnipq = i;
789 maxnipq_update();
790 return (0);
791}
792
793SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
794 NULL, 0, sysctl_maxnipq, "I",
795 "Maximum number of IPv4 fragment reassembly queue entries");
796
797/*
798 * Take incoming datagram fragment and try to reassemble it into
799 * whole datagram. If the argument is the first fragment or one
800 * in between the function will return NULL and store the mbuf
801 * in the fragment chain. If the argument is the last fragment
802 * the packet will be reassembled and the pointer to the new
803 * mbuf returned for further processing. Only m_tags attached
804 * to the first packet/fragment are preserved.
805 * The IP header is *NOT* adjusted out of iplen.
806 */
807struct mbuf *
808ip_reass(struct mbuf *m)
809{
810 struct ip *ip;
811 struct mbuf *p, *q, *nq, *t;
812 struct ipq *fp = NULL;
813 struct ipqhead *head;
814 int i, hlen, next;
815 u_int8_t ecn, ecn0;
816 u_short hash;
817
818 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
819 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) {
820 IPSTAT_INC(ips_fragments);
821 IPSTAT_INC(ips_fragdropped);
822 m_freem(m);
823 return (NULL);
824 }
825
826 ip = mtod(m, struct ip *);
827 hlen = ip->ip_hl << 2;
828
829 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
830 head = &V_ipq[hash];
831 IPQ_LOCK();
832
833 /*
834 * Look for queue of fragments
835 * of this datagram.
836 */
837 TAILQ_FOREACH(fp, head, ipq_list)
838 if (ip->ip_id == fp->ipq_id &&
839 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
840 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
841#ifdef MAC
842 mac_ipq_match(m, fp) &&
843#endif
844 ip->ip_p == fp->ipq_p)
845 goto found;
846
847 fp = NULL;
848
849 /*
850 * Attempt to trim the number of allocated fragment queues if it
851 * exceeds the administrative limit.
852 */
853 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) {
854 /*
855 * drop something from the tail of the current queue
856 * before proceeding further
857 */
858 struct ipq *q = TAILQ_LAST(head, ipqhead);
859 if (q == NULL) { /* gak */
860 for (i = 0; i < IPREASS_NHASH; i++) {
861 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead);
862 if (r) {
863 IPSTAT_ADD(ips_fragtimeout,
864 r->ipq_nfrags);
865 ip_freef(&V_ipq[i], r);
866 break;
867 }
868 }
869 } else {
870 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags);
871 ip_freef(head, q);
872 }
873 }
874
875found:
876 /*
877 * Adjust ip_len to not reflect header,
878 * convert offset of this to bytes.
879 */
880 ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
881 if (ip->ip_off & htons(IP_MF)) {
882 /*
883 * Make sure that fragments have a data length
884 * that's a non-zero multiple of 8 bytes.
885 */
886 if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) {
887 IPSTAT_INC(ips_toosmall); /* XXX */
888 goto dropfrag;
889 }
890 m->m_flags |= M_IP_FRAG;
891 } else
892 m->m_flags &= ~M_IP_FRAG;
893 ip->ip_off = htons(ntohs(ip->ip_off) << 3);
894
895 /*
896 * Attempt reassembly; if it succeeds, proceed.
897 * ip_reass() will return a different mbuf.
898 */
899 IPSTAT_INC(ips_fragments);
900 m->m_pkthdr.PH_loc.ptr = ip;
901
902 /* Previous ip_reass() started here. */
903 /*
904 * Presence of header sizes in mbufs
905 * would confuse code below.
906 */
907 m->m_data += hlen;
908 m->m_len -= hlen;
909
910 /*
911 * If first fragment to arrive, create a reassembly queue.
912 */
913 if (fp == NULL) {
914 fp = uma_zalloc(V_ipq_zone, M_NOWAIT);
915 if (fp == NULL)
916 goto dropfrag;
917#ifdef MAC
918 if (mac_ipq_init(fp, M_NOWAIT) != 0) {
919 uma_zfree(V_ipq_zone, fp);
920 fp = NULL;
921 goto dropfrag;
922 }
923 mac_ipq_create(m, fp);
924#endif
925 TAILQ_INSERT_HEAD(head, fp, ipq_list);
926 V_nipq++;
927 fp->ipq_nfrags = 1;
928 fp->ipq_ttl = IPFRAGTTL;
929 fp->ipq_p = ip->ip_p;
930 fp->ipq_id = ip->ip_id;
931 fp->ipq_src = ip->ip_src;
932 fp->ipq_dst = ip->ip_dst;
933 fp->ipq_frags = m;
934 m->m_nextpkt = NULL;
935 goto done;
936 } else {
937 fp->ipq_nfrags++;
938#ifdef MAC
939 mac_ipq_update(m, fp);
940#endif
941 }
942
943#define GETIP(m) ((struct ip*)((m)->m_pkthdr.PH_loc.ptr))
944
945 /*
946 * Handle ECN by comparing this segment with the first one;
947 * if CE is set, do not lose CE.
948 * drop if CE and not-ECT are mixed for the same packet.
949 */
950 ecn = ip->ip_tos & IPTOS_ECN_MASK;
951 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
952 if (ecn == IPTOS_ECN_CE) {
953 if (ecn0 == IPTOS_ECN_NOTECT)
954 goto dropfrag;
955 if (ecn0 != IPTOS_ECN_CE)
956 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
957 }
958 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
959 goto dropfrag;
960
961 /*
962 * Find a segment which begins after this one does.
963 */
964 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
965 if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off))
966 break;
967
968 /*
969 * If there is a preceding segment, it may provide some of
970 * our data already. If so, drop the data from the incoming
971 * segment. If it provides all of our data, drop us, otherwise
972 * stick new segment in the proper place.
973 *
974 * If some of the data is dropped from the preceding
975 * segment, then it's checksum is invalidated.
976 */
977 if (p) {
978 i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) -
979 ntohs(ip->ip_off);
980 if (i > 0) {
981 if (i >= ntohs(ip->ip_len))
982 goto dropfrag;
983 m_adj(m, i);
984 m->m_pkthdr.csum_flags = 0;
985 ip->ip_off = htons(ntohs(ip->ip_off) + i);
986 ip->ip_len = htons(ntohs(ip->ip_len) - i);
987 }
988 m->m_nextpkt = p->m_nextpkt;
989 p->m_nextpkt = m;
990 } else {
991 m->m_nextpkt = fp->ipq_frags;
992 fp->ipq_frags = m;
993 }
994
995 /*
996 * While we overlap succeeding segments trim them or,
997 * if they are completely covered, dequeue them.
998 */
999 for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) >
1000 ntohs(GETIP(q)->ip_off); q = nq) {
1001 i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) -
1002 ntohs(GETIP(q)->ip_off);
1003 if (i < ntohs(GETIP(q)->ip_len)) {
1004 GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i);
1005 GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i);
1006 m_adj(q, i);
1007 q->m_pkthdr.csum_flags = 0;
1008 break;
1009 }
1010 nq = q->m_nextpkt;
1011 m->m_nextpkt = nq;
1012 IPSTAT_INC(ips_fragdropped);
1013 fp->ipq_nfrags--;
1014 m_freem(q);
1015 }
1016
1017 /*
1018 * Check for complete reassembly and perform frag per packet
1019 * limiting.
1020 *
1021 * Frag limiting is performed here so that the nth frag has
1022 * a chance to complete the packet before we drop the packet.
1023 * As a result, n+1 frags are actually allowed per packet, but
1024 * only n will ever be stored. (n = maxfragsperpacket.)
1025 *
1026 */
1027 next = 0;
1028 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1029 if (ntohs(GETIP(q)->ip_off) != next) {
1030 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1031 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1032 ip_freef(head, fp);
1033 }
1034 goto done;
1035 }
1036 next += ntohs(GETIP(q)->ip_len);
1037 }
1038 /* Make sure the last packet didn't have the IP_MF flag */
1039 if (p->m_flags & M_IP_FRAG) {
1040 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1041 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1042 ip_freef(head, fp);
1043 }
1044 goto done;
1045 }
1046
1047 /*
1048 * Reassembly is complete. Make sure the packet is a sane size.
1049 */
1050 q = fp->ipq_frags;
1051 ip = GETIP(q);
1052 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
1053 IPSTAT_INC(ips_toolong);
1054 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1055 ip_freef(head, fp);
1056 goto done;
1057 }
1058
1059 /*
1060 * Concatenate fragments.
1061 */
1062 m = q;
1063 t = m->m_next;
1064 m->m_next = NULL;
1065 m_cat(m, t);
1066 nq = q->m_nextpkt;
1067 q->m_nextpkt = NULL;
1068 for (q = nq; q != NULL; q = nq) {
1069 nq = q->m_nextpkt;
1070 q->m_nextpkt = NULL;
1071 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1072 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1073 m_cat(m, q);
1074 }
1075 /*
1076 * In order to do checksumming faster we do 'end-around carry' here
1077 * (and not in for{} loop), though it implies we are not going to
1078 * reassemble more than 64k fragments.
1079 */
1080 m->m_pkthdr.csum_data =
1081 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16);
1082#ifdef MAC
1083 mac_ipq_reassemble(fp, m);
1084 mac_ipq_destroy(fp);
1085#endif
1086
1087 /*
1088 * Create header for new ip packet by modifying header of first
1089 * packet; dequeue and discard fragment reassembly header.
1090 * Make header visible.
1091 */
1092 ip->ip_len = htons((ip->ip_hl << 2) + next);
1093 ip->ip_src = fp->ipq_src;
1094 ip->ip_dst = fp->ipq_dst;
1095 TAILQ_REMOVE(head, fp, ipq_list);
1096 V_nipq--;
1097 uma_zfree(V_ipq_zone, fp);
1098 m->m_len += (ip->ip_hl << 2);
1099 m->m_data -= (ip->ip_hl << 2);
1100 /* some debugging cruft by sklower, below, will go away soon */
1101 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
1102 m_fixhdr(m);
1103 IPSTAT_INC(ips_reassembled);
1104 IPQ_UNLOCK();
1105 return (m);
1106
1107dropfrag:
1108 IPSTAT_INC(ips_fragdropped);
1109 if (fp != NULL)
1110 fp->ipq_nfrags--;
1111 m_freem(m);
1112done:
1113 IPQ_UNLOCK();
1114 return (NULL);
1115
1116#undef GETIP
1117}
1118
1119/*
1120 * Free a fragment reassembly header and all
1121 * associated datagrams.
1122 */
1123static void
1124ip_freef(struct ipqhead *fhp, struct ipq *fp)
1125{
1126 struct mbuf *q;
1127
1128 IPQ_LOCK_ASSERT();
1129
1130 while (fp->ipq_frags) {
1131 q = fp->ipq_frags;
1132 fp->ipq_frags = q->m_nextpkt;
1133 m_freem(q);
1134 }
1135 TAILQ_REMOVE(fhp, fp, ipq_list);
1136 uma_zfree(V_ipq_zone, fp);
1137 V_nipq--;
1138}
1139
1140/*
1141 * IP timer processing;
1142 * if a timer expires on a reassembly
1143 * queue, discard it.
1144 */
1145void
1146ip_slowtimo(void)
1147{
1148 VNET_ITERATOR_DECL(vnet_iter);
1149 struct ipq *fp;
1150 int i;
1151
1152 VNET_LIST_RLOCK_NOSLEEP();
1153 IPQ_LOCK();
1154 VNET_FOREACH(vnet_iter) {
1155 CURVNET_SET(vnet_iter);
1156 for (i = 0; i < IPREASS_NHASH; i++) {
1157 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) {
1158 struct ipq *fpp;
1159
1160 fpp = fp;
1161 fp = TAILQ_NEXT(fp, ipq_list);
1162 if(--fpp->ipq_ttl == 0) {
1163 IPSTAT_ADD(ips_fragtimeout,
1164 fpp->ipq_nfrags);
1165 ip_freef(&V_ipq[i], fpp);
1166 }
1167 }
1168 }
1169 /*
1170 * If we are over the maximum number of fragments
1171 * (due to the limit being lowered), drain off
1172 * enough to get down to the new limit.
1173 */
1174 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) {
1175 for (i = 0; i < IPREASS_NHASH; i++) {
1176 while (V_nipq > V_maxnipq &&
1177 !TAILQ_EMPTY(&V_ipq[i])) {
1178 IPSTAT_ADD(ips_fragdropped,
1179 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1180 ip_freef(&V_ipq[i],
1181 TAILQ_FIRST(&V_ipq[i]));
1182 }
1183 }
1184 }
1185 CURVNET_RESTORE();
1186 }
1187 IPQ_UNLOCK();
1188 VNET_LIST_RUNLOCK_NOSLEEP();
1189}
1190
1191/*
1192 * Drain off all datagram fragments.
1193 */
1194static void
1195ip_drain_locked(void)
1196{
1197 int i;
1198
1199 IPQ_LOCK_ASSERT();
1200
1201 for (i = 0; i < IPREASS_NHASH; i++) {
1202 while(!TAILQ_EMPTY(&V_ipq[i])) {
1203 IPSTAT_ADD(ips_fragdropped,
1204 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1205 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i]));
1206 }
1207 }
1208}
1209
1210void
1211ip_drain(void)
1212{
1213 VNET_ITERATOR_DECL(vnet_iter);
1214
1215 VNET_LIST_RLOCK_NOSLEEP();
1216 IPQ_LOCK();
1217 VNET_FOREACH(vnet_iter) {
1218 CURVNET_SET(vnet_iter);
1219 ip_drain_locked();
1220 CURVNET_RESTORE();
1221 }
1222 IPQ_UNLOCK();
1223 VNET_LIST_RUNLOCK_NOSLEEP();
1224 in_rtqdrain();
1225}
1226
1227/*
1228 * The protocol to be inserted into ip_protox[] must be already registered
1229 * in inetsw[], either statically or through pf_proto_register().
1230 */
1231int
1232ipproto_register(short ipproto)
1233{
1234 struct protosw *pr;
1235
1236 /* Sanity checks. */
1237 if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
1238 return (EPROTONOSUPPORT);
1239
1240 /*
1241 * The protocol slot must not be occupied by another protocol
1242 * already. An index pointing to IPPROTO_RAW is unused.
1243 */
1244 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1245 if (pr == NULL)
1246 return (EPFNOSUPPORT);
1247 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
1248 return (EEXIST);
1249
1250 /* Find the protocol position in inetsw[] and set the index. */
1251 for (pr = inetdomain.dom_protosw;
1252 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
1253 if (pr->pr_domain->dom_family == PF_INET &&
1254 pr->pr_protocol && pr->pr_protocol == ipproto) {
1255 ip_protox[pr->pr_protocol] = pr - inetsw;
1256 return (0);
1257 }
1258 }
1259 return (EPROTONOSUPPORT);
1260}
1261
1262int
1263ipproto_unregister(short ipproto)
1264{
1265 struct protosw *pr;
1266
1267 /* Sanity checks. */
1268 if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
1269 return (EPROTONOSUPPORT);
1270
1271 /* Check if the protocol was indeed registered. */
1272 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1273 if (pr == NULL)
1274 return (EPFNOSUPPORT);
1275 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
1276 return (ENOENT);
1277
1278 /* Reset the protocol slot to IPPROTO_RAW. */
1279 ip_protox[ipproto] = pr - inetsw;
1280 return (0);
1281}
1282
1283/*
1284 * Given address of next destination (final or next hop), return (referenced)
1285 * internet address info of interface to be used to get there.
1286 */
1287struct in_ifaddr *
1288ip_rtaddr(struct in_addr dst, u_int fibnum)
1289{
1290 struct route sro;
1291 struct sockaddr_in *sin;
1292 struct in_ifaddr *ia;
1293
1294 bzero(&sro, sizeof(sro));
1295 sin = (struct sockaddr_in *)&sro.ro_dst;
1296 sin->sin_family = AF_INET;
1297 sin->sin_len = sizeof(*sin);
1298 sin->sin_addr = dst;
1299 in_rtalloc_ign(&sro, 0, fibnum);
1300
1301 if (sro.ro_rt == NULL)
1302 return (NULL);
1303
1304 ia = ifatoia(sro.ro_rt->rt_ifa);
1305 ifa_ref(&ia->ia_ifa);
1306 RTFREE(sro.ro_rt);
1307 return (ia);
1308}
1309
1310u_char inetctlerrmap[PRC_NCMDS] = {
1311 0, 0, 0, 0,
1312 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1313 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1314 EMSGSIZE, EHOSTUNREACH, 0, 0,
1315 0, 0, EHOSTUNREACH, 0,
1316 ENOPROTOOPT, ECONNREFUSED
1317};
1318
1319/*
1320 * Forward a packet. If some error occurs return the sender
1321 * an icmp packet. Note we can't always generate a meaningful
1322 * icmp message because icmp doesn't have a large enough repertoire
1323 * of codes and types.
1324 *
1325 * If not forwarding, just drop the packet. This could be confusing
1326 * if ipforwarding was zero but some routing protocol was advancing
1327 * us as a gateway to somewhere. However, we must let the routing
1328 * protocol deal with that.
1329 *
1330 * The srcrt parameter indicates whether the packet is being forwarded
1331 * via a source route.
1332 */
1333void
1334ip_forward(struct mbuf *m, int srcrt)
1335{
1336 struct ip *ip = mtod(m, struct ip *);
1337 struct in_ifaddr *ia;
1338 struct mbuf *mcopy;
1339 struct in_addr dest;
1340 struct route ro;
1341 int error, type = 0, code = 0, mtu = 0;
1342
1343 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1344 IPSTAT_INC(ips_cantforward);
1345 m_freem(m);
1346 return;
1347 }
1348#ifdef IPSTEALTH
1349 if (!V_ipstealth) {
1350#endif
1351 if (ip->ip_ttl <= IPTTLDEC) {
1352 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
1353 0, 0);
1354 return;
1355 }
1356#ifdef IPSTEALTH
1357 }
1358#endif
1359
1360 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
1361#ifndef IPSEC
1362 /*
1363 * 'ia' may be NULL if there is no route for this destination.
1364 * In case of IPsec, Don't discard it just yet, but pass it to
1365 * ip_output in case of outgoing IPsec policy.
1366 */
1367 if (!srcrt && ia == NULL) {
1368 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
1369 return;
1370 }
1371#endif
1372
1373 /*
1374 * Save the IP header and at most 8 bytes of the payload,
1375 * in case we need to generate an ICMP message to the src.
1376 *
1377 * XXX this can be optimized a lot by saving the data in a local
1378 * buffer on the stack (72 bytes at most), and only allocating the
1379 * mbuf if really necessary. The vast majority of the packets
1380 * are forwarded without having to send an ICMP back (either
1381 * because unnecessary, or because rate limited), so we are
1382 * really we are wasting a lot of work here.
1383 *
1384 * We don't use m_copy() because it might return a reference
1385 * to a shared cluster. Both this function and ip_output()
1386 * assume exclusive access to the IP header in `m', so any
1387 * data in a cluster may change before we reach icmp_error().
1388 */
1389 mcopy = m_gethdr(M_NOWAIT, m->m_type);
1390 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) {
1391 /*
1392 * It's probably ok if the pkthdr dup fails (because
1393 * the deep copy of the tag chain failed), but for now
1394 * be conservative and just discard the copy since
1395 * code below may some day want the tags.
1396 */
1397 m_free(mcopy);
1398 mcopy = NULL;
1399 }
1400 if (mcopy != NULL) {
1401 mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy));
1402 mcopy->m_pkthdr.len = mcopy->m_len;
1403 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1404 }
1405
1406#ifdef IPSTEALTH
1407 if (!V_ipstealth) {
1408#endif
1409 ip->ip_ttl -= IPTTLDEC;
1410#ifdef IPSTEALTH
1411 }
1412#endif
1413
1414 /*
1415 * If forwarding packet using same interface that it came in on,
1416 * perhaps should send a redirect to sender to shortcut a hop.
1417 * Only send redirect if source is sending directly to us,
1418 * and if packet was not source routed (or has any options).
1419 * Also, don't send redirect if forwarding using a default route
1420 * or a route modified by a redirect.
1421 */
1422 dest.s_addr = 0;
1423 if (!srcrt && V_ipsendredirects &&
1424 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
1425 struct sockaddr_in *sin;
1426 struct rtentry *rt;
1427
1428 bzero(&ro, sizeof(ro));
1429 sin = (struct sockaddr_in *)&ro.ro_dst;
1430 sin->sin_family = AF_INET;
1431 sin->sin_len = sizeof(*sin);
1432 sin->sin_addr = ip->ip_dst;
1433 in_rtalloc_ign(&ro, 0, M_GETFIB(m));
1434
1435 rt = ro.ro_rt;
1436
1437 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1438 satosin(rt_key(rt))->sin_addr.s_addr != 0) {
1439#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1440 u_long src = ntohl(ip->ip_src.s_addr);
1441
1442 if (RTA(rt) &&
1443 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1444 if (rt->rt_flags & RTF_GATEWAY)
1445 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
1446 else
1447 dest.s_addr = ip->ip_dst.s_addr;
1448 /* Router requirements says to only send host redirects */
1449 type = ICMP_REDIRECT;
1450 code = ICMP_REDIRECT_HOST;
1451 }
1452 }
1453 if (rt)
1454 RTFREE(rt);
1455 }
1456
1457 /*
1458 * Try to cache the route MTU from ip_output so we can consider it for
1459 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191.
1460 */
1461 bzero(&ro, sizeof(ro));
1462
1463 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
1464
1465 if (error == EMSGSIZE && ro.ro_rt)
| 34
35#include "opt_bootp.h"
36#include "opt_ipfw.h"
37#include "opt_ipstealth.h"
38#include "opt_ipsec.h"
39#include "opt_route.h"
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/mbuf.h>
44#include <sys/malloc.h>
45#include <sys/domain.h>
46#include <sys/protosw.h>
47#include <sys/socket.h>
48#include <sys/time.h>
49#include <sys/kernel.h>
50#include <sys/lock.h>
51#include <sys/rwlock.h>
52#include <sys/sdt.h>
53#include <sys/syslog.h>
54#include <sys/sysctl.h>
55
56#include <net/pfil.h>
57#include <net/if.h>
58#include <net/if_types.h>
59#include <net/if_var.h>
60#include <net/if_dl.h>
61#include <net/route.h>
62#include <net/netisr.h>
63#include <net/vnet.h>
64
65#include <netinet/in.h>
66#include <netinet/in_kdtrace.h>
67#include <netinet/in_systm.h>
68#include <netinet/in_var.h>
69#include <netinet/ip.h>
70#include <netinet/in_pcb.h>
71#include <netinet/ip_var.h>
72#include <netinet/ip_fw.h>
73#include <netinet/ip_icmp.h>
74#include <netinet/ip_options.h>
75#include <machine/in_cksum.h>
76#include <netinet/ip_carp.h>
77#ifdef IPSEC
78#include <netinet/ip_ipsec.h>
79#endif /* IPSEC */
80
81#include <sys/socketvar.h>
82
83#include <security/mac/mac_framework.h>
84
85#ifdef CTASSERT
86CTASSERT(sizeof(struct ip) == 20);
87#endif
88
89struct rwlock in_ifaddr_lock;
90RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock");
91
92VNET_DEFINE(int, rsvp_on);
93
94VNET_DEFINE(int, ipforwarding);
95SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
96 &VNET_NAME(ipforwarding), 0,
97 "Enable IP forwarding between interfaces");
98
99static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */
100#define V_ipsendredirects VNET(ipsendredirects)
101SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
102 &VNET_NAME(ipsendredirects), 0,
103 "Enable sending IP redirects");
104
105static VNET_DEFINE(int, ip_keepfaith);
106#define V_ip_keepfaith VNET(ip_keepfaith)
107SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
108 &VNET_NAME(ip_keepfaith), 0,
109 "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
110
111static VNET_DEFINE(int, ip_sendsourcequench);
112#define V_ip_sendsourcequench VNET(ip_sendsourcequench)
113SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
114 &VNET_NAME(ip_sendsourcequench), 0,
115 "Enable the transmission of source quench packets");
116
117VNET_DEFINE(int, ip_do_randomid);
118SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
119 &VNET_NAME(ip_do_randomid), 0,
120 "Assign random ip_id values");
121
122/*
123 * XXX - Setting ip_checkinterface mostly implements the receive side of
124 * the Strong ES model described in RFC 1122, but since the routing table
125 * and transmit implementation do not implement the Strong ES model,
126 * setting this to 1 results in an odd hybrid.
127 *
128 * XXX - ip_checkinterface currently must be disabled if you use ipnat
129 * to translate the destination address to another local interface.
130 *
131 * XXX - ip_checkinterface must be disabled if you add IP aliases
132 * to the loopback interface instead of the interface where the
133 * packets for those addresses are received.
134 */
135static VNET_DEFINE(int, ip_checkinterface);
136#define V_ip_checkinterface VNET(ip_checkinterface)
137SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
138 &VNET_NAME(ip_checkinterface), 0,
139 "Verify packet arrives on correct interface");
140
141VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */
142
143static struct netisr_handler ip_nh = {
144 .nh_name = "ip",
145 .nh_handler = ip_input,
146 .nh_proto = NETISR_IP,
147 .nh_policy = NETISR_POLICY_FLOW,
148};
149
150extern struct domain inetdomain;
151extern struct protosw inetsw[];
152u_char ip_protox[IPPROTO_MAX];
153VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */
154VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */
155VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */
156
157static VNET_DEFINE(uma_zone_t, ipq_zone);
158static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]);
159static struct mtx ipqlock;
160
161#define V_ipq_zone VNET(ipq_zone)
162#define V_ipq VNET(ipq)
163
164#define IPQ_LOCK() mtx_lock(&ipqlock)
165#define IPQ_UNLOCK() mtx_unlock(&ipqlock)
166#define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
167#define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
168
169static void maxnipq_update(void);
170static void ipq_zone_change(void *);
171static void ip_drain_locked(void);
172
173static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */
174static VNET_DEFINE(int, nipq); /* Total # of reass queues */
175#define V_maxnipq VNET(maxnipq)
176#define V_nipq VNET(nipq)
177SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD,
178 &VNET_NAME(nipq), 0,
179 "Current number of IPv4 fragment reassembly queue entries");
180
181static VNET_DEFINE(int, maxfragsperpacket);
182#define V_maxfragsperpacket VNET(maxfragsperpacket)
183SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
184 &VNET_NAME(maxfragsperpacket), 0,
185 "Maximum number of IPv4 fragments allowed per packet");
186
187#ifdef IPCTL_DEFMTU
188SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
189 &ip_mtu, 0, "Default MTU");
190#endif
191
192#ifdef IPSTEALTH
193VNET_DEFINE(int, ipstealth);
194SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
195 &VNET_NAME(ipstealth), 0,
196 "IP stealth mode, no TTL decrementation on forwarding");
197#endif
198
199static void ip_freef(struct ipqhead *, struct ipq *);
200
201/*
202 * IP statistics are stored in the "array" of counter(9)s.
203 */
204VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat);
205VNET_PCPUSTAT_SYSINIT(ipstat);
206SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat,
207 "IP statistics (struct ipstat, netinet/ip_var.h)");
208
209#ifdef VIMAGE
210VNET_PCPUSTAT_SYSUNINIT(ipstat);
211#endif /* VIMAGE */
212
213/*
214 * Kernel module interface for updating ipstat. The argument is an index
215 * into ipstat treated as an array.
216 */
217void
218kmod_ipstat_inc(int statnum)
219{
220
221 counter_u64_add(VNET(ipstat)[statnum], 1);
222}
223
224void
225kmod_ipstat_dec(int statnum)
226{
227
228 counter_u64_add(VNET(ipstat)[statnum], -1);
229}
230
231static int
232sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
233{
234 int error, qlimit;
235
236 netisr_getqlimit(&ip_nh, &qlimit);
237 error = sysctl_handle_int(oidp, &qlimit, 0, req);
238 if (error || !req->newptr)
239 return (error);
240 if (qlimit < 1)
241 return (EINVAL);
242 return (netisr_setqlimit(&ip_nh, qlimit));
243}
244SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
245 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I",
246 "Maximum size of the IP input queue");
247
248static int
249sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
250{
251 u_int64_t qdrops_long;
252 int error, qdrops;
253
254 netisr_getqdrops(&ip_nh, &qdrops_long);
255 qdrops = qdrops_long;
256 error = sysctl_handle_int(oidp, &qdrops, 0, req);
257 if (error || !req->newptr)
258 return (error);
259 if (qdrops != 0)
260 return (EINVAL);
261 netisr_clearqdrops(&ip_nh);
262 return (0);
263}
264
265SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
266 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I",
267 "Number of packets dropped from the IP input queue");
268
269/*
270 * IP initialization: fill in IP protocol switch table.
271 * All protocols not implemented in kernel go to raw IP protocol handler.
272 */
273void
274ip_init(void)
275{
276 struct protosw *pr;
277 int i;
278
279 V_ip_id = time_second & 0xffff;
280
281 TAILQ_INIT(&V_in_ifaddrhead);
282 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
283
284 /* Initialize IP reassembly queue. */
285 for (i = 0; i < IPREASS_NHASH; i++)
286 TAILQ_INIT(&V_ipq[i]);
287 V_maxnipq = nmbclusters / 32;
288 V_maxfragsperpacket = 16;
289 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
290 NULL, UMA_ALIGN_PTR, 0);
291 maxnipq_update();
292
293 /* Initialize packet filter hooks. */
294 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF;
295 V_inet_pfil_hook.ph_af = AF_INET;
296 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0)
297 printf("%s: WARNING: unable to register pfil hook, "
298 "error %d\n", __func__, i);
299
300 /* Skip initialization of globals for non-default instances. */
301 if (!IS_DEFAULT_VNET(curvnet))
302 return;
303
304 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
305 if (pr == NULL)
306 panic("ip_init: PF_INET not found");
307
308 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
309 for (i = 0; i < IPPROTO_MAX; i++)
310 ip_protox[i] = pr - inetsw;
311 /*
312 * Cycle through IP protocols and put them into the appropriate place
313 * in ip_protox[].
314 */
315 for (pr = inetdomain.dom_protosw;
316 pr < inetdomain.dom_protoswNPROTOSW; pr++)
317 if (pr->pr_domain->dom_family == PF_INET &&
318 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
319 /* Be careful to only index valid IP protocols. */
320 if (pr->pr_protocol < IPPROTO_MAX)
321 ip_protox[pr->pr_protocol] = pr - inetsw;
322 }
323
324 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change,
325 NULL, EVENTHANDLER_PRI_ANY);
326
327 /* Initialize various other remaining things. */
328 IPQ_LOCK_INIT();
329 netisr_register(&ip_nh);
330}
331
332#ifdef VIMAGE
333void
334ip_destroy(void)
335{
336 int i;
337
338 if ((i = pfil_head_unregister(&V_inet_pfil_hook)) != 0)
339 printf("%s: WARNING: unable to unregister pfil hook, "
340 "error %d\n", __func__, i);
341
342 /* Cleanup in_ifaddr hash table; should be empty. */
343 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
344
345 IPQ_LOCK();
346 ip_drain_locked();
347 IPQ_UNLOCK();
348
349 uma_zdestroy(V_ipq_zone);
350}
351#endif
352
353/*
354 * Ip input routine. Checksum and byte swap header. If fragmented
355 * try to reassemble. Process options. Pass to next level.
356 */
357void
358ip_input(struct mbuf *m)
359{
360 struct ip *ip = NULL;
361 struct in_ifaddr *ia = NULL;
362 struct ifaddr *ifa;
363 struct ifnet *ifp;
364 int checkif, hlen = 0;
365 uint16_t sum, ip_len;
366 int dchg = 0; /* dest changed after fw */
367 struct in_addr odst; /* original dst address */
368
369 M_ASSERTPKTHDR(m);
370
371 if (m->m_flags & M_FASTFWD_OURS) {
372 m->m_flags &= ~M_FASTFWD_OURS;
373 /* Set up some basics that will be used later. */
374 ip = mtod(m, struct ip *);
375 hlen = ip->ip_hl << 2;
376 ip_len = ntohs(ip->ip_len);
377 goto ours;
378 }
379
380 IPSTAT_INC(ips_total);
381
382 if (m->m_pkthdr.len < sizeof(struct ip))
383 goto tooshort;
384
385 if (m->m_len < sizeof (struct ip) &&
386 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
387 IPSTAT_INC(ips_toosmall);
388 return;
389 }
390 ip = mtod(m, struct ip *);
391
392 if (ip->ip_v != IPVERSION) {
393 IPSTAT_INC(ips_badvers);
394 goto bad;
395 }
396
397 hlen = ip->ip_hl << 2;
398 if (hlen < sizeof(struct ip)) { /* minimum header length */
399 IPSTAT_INC(ips_badhlen);
400 goto bad;
401 }
402 if (hlen > m->m_len) {
403 if ((m = m_pullup(m, hlen)) == NULL) {
404 IPSTAT_INC(ips_badhlen);
405 return;
406 }
407 ip = mtod(m, struct ip *);
408 }
409
410 IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL);
411
412 /* 127/8 must not appear on wire - RFC1122 */
413 ifp = m->m_pkthdr.rcvif;
414 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
415 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
416 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
417 IPSTAT_INC(ips_badaddr);
418 goto bad;
419 }
420 }
421
422 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
423 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
424 } else {
425 if (hlen == sizeof(struct ip)) {
426 sum = in_cksum_hdr(ip);
427 } else {
428 sum = in_cksum(m, hlen);
429 }
430 }
431 if (sum) {
432 IPSTAT_INC(ips_badsum);
433 goto bad;
434 }
435
436#ifdef ALTQ
437 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
438 /* packet is dropped by traffic conditioner */
439 return;
440#endif
441
442 ip_len = ntohs(ip->ip_len);
443 if (ip_len < hlen) {
444 IPSTAT_INC(ips_badlen);
445 goto bad;
446 }
447
448 /*
449 * Check that the amount of data in the buffers
450 * is as at least much as the IP header would have us expect.
451 * Trim mbufs if longer than we expect.
452 * Drop packet if shorter than we expect.
453 */
454 if (m->m_pkthdr.len < ip_len) {
455tooshort:
456 IPSTAT_INC(ips_tooshort);
457 goto bad;
458 }
459 if (m->m_pkthdr.len > ip_len) {
460 if (m->m_len == m->m_pkthdr.len) {
461 m->m_len = ip_len;
462 m->m_pkthdr.len = ip_len;
463 } else
464 m_adj(m, ip_len - m->m_pkthdr.len);
465 }
466#ifdef IPSEC
467 /*
468 * Bypass packet filtering for packets previously handled by IPsec.
469 */
470 if (ip_ipsec_filtertunnel(m))
471 goto passin;
472#endif /* IPSEC */
473
474 /*
475 * Run through list of hooks for input packets.
476 *
477 * NB: Beware of the destination address changing (e.g.
478 * by NAT rewriting). When this happens, tell
479 * ip_forward to do the right thing.
480 */
481
482 /* Jump over all PFIL processing if hooks are not active. */
483 if (!PFIL_HOOKED(&V_inet_pfil_hook))
484 goto passin;
485
486 odst = ip->ip_dst;
487 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0)
488 return;
489 if (m == NULL) /* consumed by filter */
490 return;
491
492 ip = mtod(m, struct ip *);
493 dchg = (odst.s_addr != ip->ip_dst.s_addr);
494 ifp = m->m_pkthdr.rcvif;
495
496 if (m->m_flags & M_FASTFWD_OURS) {
497 m->m_flags &= ~M_FASTFWD_OURS;
498 goto ours;
499 }
500 if (m->m_flags & M_IP_NEXTHOP) {
501 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL);
502 if (dchg != 0) {
503 /*
504 * Directly ship the packet on. This allows
505 * forwarding packets originally destined to us
506 * to some other directly connected host.
507 */
508 ip_forward(m, 1);
509 return;
510 }
511 }
512passin:
513
514 /*
515 * Process options and, if not destined for us,
516 * ship it on. ip_dooptions returns 1 when an
517 * error was detected (causing an icmp message
518 * to be sent and the original packet to be freed).
519 */
520 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
521 return;
522
523 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
524 * matter if it is destined to another node, or whether it is
525 * a multicast one, RSVP wants it! and prevents it from being forwarded
526 * anywhere else. Also checks if the rsvp daemon is running before
527 * grabbing the packet.
528 */
529 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP)
530 goto ours;
531
532 /*
533 * Check our list of addresses, to see if the packet is for us.
534 * If we don't have any addresses, assume any unicast packet
535 * we receive might be for us (and let the upper layers deal
536 * with it).
537 */
538 if (TAILQ_EMPTY(&V_in_ifaddrhead) &&
539 (m->m_flags & (M_MCAST|M_BCAST)) == 0)
540 goto ours;
541
542 /*
543 * Enable a consistency check between the destination address
544 * and the arrival interface for a unicast packet (the RFC 1122
545 * strong ES model) if IP forwarding is disabled and the packet
546 * is not locally generated and the packet is not subject to
547 * 'ipfw fwd'.
548 *
549 * XXX - Checking also should be disabled if the destination
550 * address is ipnat'ed to a different interface.
551 *
552 * XXX - Checking is incompatible with IP aliases added
553 * to the loopback interface instead of the interface where
554 * the packets are received.
555 *
556 * XXX - This is the case for carp vhost IPs as well so we
557 * insert a workaround. If the packet got here, we already
558 * checked with carp_iamatch() and carp_forus().
559 */
560 checkif = V_ip_checkinterface && (V_ipforwarding == 0) &&
561 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
562 ifp->if_carp == NULL && (dchg == 0);
563
564 /*
565 * Check for exact addresses in the hash bucket.
566 */
567 /* IN_IFADDR_RLOCK(); */
568 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
569 /*
570 * If the address matches, verify that the packet
571 * arrived via the correct interface if checking is
572 * enabled.
573 */
574 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
575 (!checkif || ia->ia_ifp == ifp)) {
576 counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
577 counter_u64_add(ia->ia_ifa.ifa_ibytes,
578 m->m_pkthdr.len);
579 /* IN_IFADDR_RUNLOCK(); */
580 goto ours;
581 }
582 }
583 /* IN_IFADDR_RUNLOCK(); */
584
585 /*
586 * Check for broadcast addresses.
587 *
588 * Only accept broadcast packets that arrive via the matching
589 * interface. Reception of forwarded directed broadcasts would
590 * be handled via ip_forward() and ether_output() with the loopback
591 * into the stack for SIMPLEX interfaces handled by ether_output().
592 */
593 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
594 IF_ADDR_RLOCK(ifp);
595 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
596 if (ifa->ifa_addr->sa_family != AF_INET)
597 continue;
598 ia = ifatoia(ifa);
599 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
600 ip->ip_dst.s_addr) {
601 counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
602 counter_u64_add(ia->ia_ifa.ifa_ibytes,
603 m->m_pkthdr.len);
604 IF_ADDR_RUNLOCK(ifp);
605 goto ours;
606 }
607#ifdef BOOTP_COMPAT
608 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
609 counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
610 counter_u64_add(ia->ia_ifa.ifa_ibytes,
611 m->m_pkthdr.len);
612 IF_ADDR_RUNLOCK(ifp);
613 goto ours;
614 }
615#endif
616 }
617 IF_ADDR_RUNLOCK(ifp);
618 ia = NULL;
619 }
620 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */
621 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
622 IPSTAT_INC(ips_cantforward);
623 m_freem(m);
624 return;
625 }
626 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
627 if (V_ip_mrouter) {
628 /*
629 * If we are acting as a multicast router, all
630 * incoming multicast packets are passed to the
631 * kernel-level multicast forwarding function.
632 * The packet is returned (relatively) intact; if
633 * ip_mforward() returns a non-zero value, the packet
634 * must be discarded, else it may be accepted below.
635 */
636 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
637 IPSTAT_INC(ips_cantforward);
638 m_freem(m);
639 return;
640 }
641
642 /*
643 * The process-level routing daemon needs to receive
644 * all multicast IGMP packets, whether or not this
645 * host belongs to their destination groups.
646 */
647 if (ip->ip_p == IPPROTO_IGMP)
648 goto ours;
649 IPSTAT_INC(ips_forward);
650 }
651 /*
652 * Assume the packet is for us, to avoid prematurely taking
653 * a lock on the in_multi hash. Protocols must perform
654 * their own filtering and update statistics accordingly.
655 */
656 goto ours;
657 }
658 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
659 goto ours;
660 if (ip->ip_dst.s_addr == INADDR_ANY)
661 goto ours;
662
663 /*
664 * FAITH(Firewall Aided Internet Translator)
665 */
666 if (ifp && ifp->if_type == IFT_FAITH) {
667 if (V_ip_keepfaith) {
668 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
669 goto ours;
670 }
671 m_freem(m);
672 return;
673 }
674
675 /*
676 * Not for us; forward if possible and desirable.
677 */
678 if (V_ipforwarding == 0) {
679 IPSTAT_INC(ips_cantforward);
680 m_freem(m);
681 } else {
682#ifdef IPSEC
683 if (ip_ipsec_fwd(m))
684 goto bad;
685#endif /* IPSEC */
686 ip_forward(m, dchg);
687 }
688 return;
689
690ours:
691#ifdef IPSTEALTH
692 /*
693 * IPSTEALTH: Process non-routing options only
694 * if the packet is destined for us.
695 */
696 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1))
697 return;
698#endif /* IPSTEALTH */
699
700 /*
701 * Attempt reassembly; if it succeeds, proceed.
702 * ip_reass() will return a different mbuf.
703 */
704 if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
705 m = ip_reass(m);
706 if (m == NULL)
707 return;
708 ip = mtod(m, struct ip *);
709 /* Get the header length of the reassembled packet */
710 hlen = ip->ip_hl << 2;
711 }
712
713#ifdef IPSEC
714 /*
715 * enforce IPsec policy checking if we are seeing last header.
716 * note that we do not visit this with protocols with pcb layer
717 * code - like udp/tcp/raw ip.
718 */
719 if (ip_ipsec_input(m))
720 goto bad;
721#endif /* IPSEC */
722
723 /*
724 * Switch out to protocol's input routine.
725 */
726 IPSTAT_INC(ips_delivered);
727
728 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
729 return;
730bad:
731 m_freem(m);
732}
733
734/*
735 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
736 * max has slightly different semantics than the sysctl, for historical
737 * reasons.
738 */
739static void
740maxnipq_update(void)
741{
742
743 /*
744 * -1 for unlimited allocation.
745 */
746 if (V_maxnipq < 0)
747 uma_zone_set_max(V_ipq_zone, 0);
748 /*
749 * Positive number for specific bound.
750 */
751 if (V_maxnipq > 0)
752 uma_zone_set_max(V_ipq_zone, V_maxnipq);
753 /*
754 * Zero specifies no further fragment queue allocation -- set the
755 * bound very low, but rely on implementation elsewhere to actually
756 * prevent allocation and reclaim current queues.
757 */
758 if (V_maxnipq == 0)
759 uma_zone_set_max(V_ipq_zone, 1);
760}
761
762static void
763ipq_zone_change(void *tag)
764{
765
766 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) {
767 V_maxnipq = nmbclusters / 32;
768 maxnipq_update();
769 }
770}
771
772static int
773sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
774{
775 int error, i;
776
777 i = V_maxnipq;
778 error = sysctl_handle_int(oidp, &i, 0, req);
779 if (error || !req->newptr)
780 return (error);
781
782 /*
783 * XXXRW: Might be a good idea to sanity check the argument and place
784 * an extreme upper bound.
785 */
786 if (i < -1)
787 return (EINVAL);
788 V_maxnipq = i;
789 maxnipq_update();
790 return (0);
791}
792
793SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
794 NULL, 0, sysctl_maxnipq, "I",
795 "Maximum number of IPv4 fragment reassembly queue entries");
796
797/*
798 * Take incoming datagram fragment and try to reassemble it into
799 * whole datagram. If the argument is the first fragment or one
800 * in between the function will return NULL and store the mbuf
801 * in the fragment chain. If the argument is the last fragment
802 * the packet will be reassembled and the pointer to the new
803 * mbuf returned for further processing. Only m_tags attached
804 * to the first packet/fragment are preserved.
805 * The IP header is *NOT* adjusted out of iplen.
806 */
807struct mbuf *
808ip_reass(struct mbuf *m)
809{
810 struct ip *ip;
811 struct mbuf *p, *q, *nq, *t;
812 struct ipq *fp = NULL;
813 struct ipqhead *head;
814 int i, hlen, next;
815 u_int8_t ecn, ecn0;
816 u_short hash;
817
818 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
819 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) {
820 IPSTAT_INC(ips_fragments);
821 IPSTAT_INC(ips_fragdropped);
822 m_freem(m);
823 return (NULL);
824 }
825
826 ip = mtod(m, struct ip *);
827 hlen = ip->ip_hl << 2;
828
829 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
830 head = &V_ipq[hash];
831 IPQ_LOCK();
832
833 /*
834 * Look for queue of fragments
835 * of this datagram.
836 */
837 TAILQ_FOREACH(fp, head, ipq_list)
838 if (ip->ip_id == fp->ipq_id &&
839 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
840 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
841#ifdef MAC
842 mac_ipq_match(m, fp) &&
843#endif
844 ip->ip_p == fp->ipq_p)
845 goto found;
846
847 fp = NULL;
848
849 /*
850 * Attempt to trim the number of allocated fragment queues if it
851 * exceeds the administrative limit.
852 */
853 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) {
854 /*
855 * drop something from the tail of the current queue
856 * before proceeding further
857 */
858 struct ipq *q = TAILQ_LAST(head, ipqhead);
859 if (q == NULL) { /* gak */
860 for (i = 0; i < IPREASS_NHASH; i++) {
861 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead);
862 if (r) {
863 IPSTAT_ADD(ips_fragtimeout,
864 r->ipq_nfrags);
865 ip_freef(&V_ipq[i], r);
866 break;
867 }
868 }
869 } else {
870 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags);
871 ip_freef(head, q);
872 }
873 }
874
875found:
876 /*
877 * Adjust ip_len to not reflect header,
878 * convert offset of this to bytes.
879 */
880 ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
881 if (ip->ip_off & htons(IP_MF)) {
882 /*
883 * Make sure that fragments have a data length
884 * that's a non-zero multiple of 8 bytes.
885 */
886 if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) {
887 IPSTAT_INC(ips_toosmall); /* XXX */
888 goto dropfrag;
889 }
890 m->m_flags |= M_IP_FRAG;
891 } else
892 m->m_flags &= ~M_IP_FRAG;
893 ip->ip_off = htons(ntohs(ip->ip_off) << 3);
894
895 /*
896 * Attempt reassembly; if it succeeds, proceed.
897 * ip_reass() will return a different mbuf.
898 */
899 IPSTAT_INC(ips_fragments);
900 m->m_pkthdr.PH_loc.ptr = ip;
901
902 /* Previous ip_reass() started here. */
903 /*
904 * Presence of header sizes in mbufs
905 * would confuse code below.
906 */
907 m->m_data += hlen;
908 m->m_len -= hlen;
909
910 /*
911 * If first fragment to arrive, create a reassembly queue.
912 */
913 if (fp == NULL) {
914 fp = uma_zalloc(V_ipq_zone, M_NOWAIT);
915 if (fp == NULL)
916 goto dropfrag;
917#ifdef MAC
918 if (mac_ipq_init(fp, M_NOWAIT) != 0) {
919 uma_zfree(V_ipq_zone, fp);
920 fp = NULL;
921 goto dropfrag;
922 }
923 mac_ipq_create(m, fp);
924#endif
925 TAILQ_INSERT_HEAD(head, fp, ipq_list);
926 V_nipq++;
927 fp->ipq_nfrags = 1;
928 fp->ipq_ttl = IPFRAGTTL;
929 fp->ipq_p = ip->ip_p;
930 fp->ipq_id = ip->ip_id;
931 fp->ipq_src = ip->ip_src;
932 fp->ipq_dst = ip->ip_dst;
933 fp->ipq_frags = m;
934 m->m_nextpkt = NULL;
935 goto done;
936 } else {
937 fp->ipq_nfrags++;
938#ifdef MAC
939 mac_ipq_update(m, fp);
940#endif
941 }
942
943#define GETIP(m) ((struct ip*)((m)->m_pkthdr.PH_loc.ptr))
944
945 /*
946 * Handle ECN by comparing this segment with the first one;
947 * if CE is set, do not lose CE.
948 * drop if CE and not-ECT are mixed for the same packet.
949 */
950 ecn = ip->ip_tos & IPTOS_ECN_MASK;
951 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
952 if (ecn == IPTOS_ECN_CE) {
953 if (ecn0 == IPTOS_ECN_NOTECT)
954 goto dropfrag;
955 if (ecn0 != IPTOS_ECN_CE)
956 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
957 }
958 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
959 goto dropfrag;
960
961 /*
962 * Find a segment which begins after this one does.
963 */
964 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
965 if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off))
966 break;
967
968 /*
969 * If there is a preceding segment, it may provide some of
970 * our data already. If so, drop the data from the incoming
971 * segment. If it provides all of our data, drop us, otherwise
972 * stick new segment in the proper place.
973 *
974 * If some of the data is dropped from the preceding
975 * segment, then it's checksum is invalidated.
976 */
977 if (p) {
978 i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) -
979 ntohs(ip->ip_off);
980 if (i > 0) {
981 if (i >= ntohs(ip->ip_len))
982 goto dropfrag;
983 m_adj(m, i);
984 m->m_pkthdr.csum_flags = 0;
985 ip->ip_off = htons(ntohs(ip->ip_off) + i);
986 ip->ip_len = htons(ntohs(ip->ip_len) - i);
987 }
988 m->m_nextpkt = p->m_nextpkt;
989 p->m_nextpkt = m;
990 } else {
991 m->m_nextpkt = fp->ipq_frags;
992 fp->ipq_frags = m;
993 }
994
995 /*
996 * While we overlap succeeding segments trim them or,
997 * if they are completely covered, dequeue them.
998 */
999 for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) >
1000 ntohs(GETIP(q)->ip_off); q = nq) {
1001 i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) -
1002 ntohs(GETIP(q)->ip_off);
1003 if (i < ntohs(GETIP(q)->ip_len)) {
1004 GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i);
1005 GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i);
1006 m_adj(q, i);
1007 q->m_pkthdr.csum_flags = 0;
1008 break;
1009 }
1010 nq = q->m_nextpkt;
1011 m->m_nextpkt = nq;
1012 IPSTAT_INC(ips_fragdropped);
1013 fp->ipq_nfrags--;
1014 m_freem(q);
1015 }
1016
1017 /*
1018 * Check for complete reassembly and perform frag per packet
1019 * limiting.
1020 *
1021 * Frag limiting is performed here so that the nth frag has
1022 * a chance to complete the packet before we drop the packet.
1023 * As a result, n+1 frags are actually allowed per packet, but
1024 * only n will ever be stored. (n = maxfragsperpacket.)
1025 *
1026 */
1027 next = 0;
1028 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1029 if (ntohs(GETIP(q)->ip_off) != next) {
1030 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1031 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1032 ip_freef(head, fp);
1033 }
1034 goto done;
1035 }
1036 next += ntohs(GETIP(q)->ip_len);
1037 }
1038 /* Make sure the last packet didn't have the IP_MF flag */
1039 if (p->m_flags & M_IP_FRAG) {
1040 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1041 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1042 ip_freef(head, fp);
1043 }
1044 goto done;
1045 }
1046
1047 /*
1048 * Reassembly is complete. Make sure the packet is a sane size.
1049 */
1050 q = fp->ipq_frags;
1051 ip = GETIP(q);
1052 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
1053 IPSTAT_INC(ips_toolong);
1054 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1055 ip_freef(head, fp);
1056 goto done;
1057 }
1058
1059 /*
1060 * Concatenate fragments.
1061 */
1062 m = q;
1063 t = m->m_next;
1064 m->m_next = NULL;
1065 m_cat(m, t);
1066 nq = q->m_nextpkt;
1067 q->m_nextpkt = NULL;
1068 for (q = nq; q != NULL; q = nq) {
1069 nq = q->m_nextpkt;
1070 q->m_nextpkt = NULL;
1071 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1072 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1073 m_cat(m, q);
1074 }
1075 /*
1076 * In order to do checksumming faster we do 'end-around carry' here
1077 * (and not in for{} loop), though it implies we are not going to
1078 * reassemble more than 64k fragments.
1079 */
1080 m->m_pkthdr.csum_data =
1081 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16);
1082#ifdef MAC
1083 mac_ipq_reassemble(fp, m);
1084 mac_ipq_destroy(fp);
1085#endif
1086
1087 /*
1088 * Create header for new ip packet by modifying header of first
1089 * packet; dequeue and discard fragment reassembly header.
1090 * Make header visible.
1091 */
1092 ip->ip_len = htons((ip->ip_hl << 2) + next);
1093 ip->ip_src = fp->ipq_src;
1094 ip->ip_dst = fp->ipq_dst;
1095 TAILQ_REMOVE(head, fp, ipq_list);
1096 V_nipq--;
1097 uma_zfree(V_ipq_zone, fp);
1098 m->m_len += (ip->ip_hl << 2);
1099 m->m_data -= (ip->ip_hl << 2);
1100 /* some debugging cruft by sklower, below, will go away soon */
1101 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
1102 m_fixhdr(m);
1103 IPSTAT_INC(ips_reassembled);
1104 IPQ_UNLOCK();
1105 return (m);
1106
1107dropfrag:
1108 IPSTAT_INC(ips_fragdropped);
1109 if (fp != NULL)
1110 fp->ipq_nfrags--;
1111 m_freem(m);
1112done:
1113 IPQ_UNLOCK();
1114 return (NULL);
1115
1116#undef GETIP
1117}
1118
1119/*
1120 * Free a fragment reassembly header and all
1121 * associated datagrams.
1122 */
1123static void
1124ip_freef(struct ipqhead *fhp, struct ipq *fp)
1125{
1126 struct mbuf *q;
1127
1128 IPQ_LOCK_ASSERT();
1129
1130 while (fp->ipq_frags) {
1131 q = fp->ipq_frags;
1132 fp->ipq_frags = q->m_nextpkt;
1133 m_freem(q);
1134 }
1135 TAILQ_REMOVE(fhp, fp, ipq_list);
1136 uma_zfree(V_ipq_zone, fp);
1137 V_nipq--;
1138}
1139
1140/*
1141 * IP timer processing;
1142 * if a timer expires on a reassembly
1143 * queue, discard it.
1144 */
1145void
1146ip_slowtimo(void)
1147{
1148 VNET_ITERATOR_DECL(vnet_iter);
1149 struct ipq *fp;
1150 int i;
1151
1152 VNET_LIST_RLOCK_NOSLEEP();
1153 IPQ_LOCK();
1154 VNET_FOREACH(vnet_iter) {
1155 CURVNET_SET(vnet_iter);
1156 for (i = 0; i < IPREASS_NHASH; i++) {
1157 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) {
1158 struct ipq *fpp;
1159
1160 fpp = fp;
1161 fp = TAILQ_NEXT(fp, ipq_list);
1162 if(--fpp->ipq_ttl == 0) {
1163 IPSTAT_ADD(ips_fragtimeout,
1164 fpp->ipq_nfrags);
1165 ip_freef(&V_ipq[i], fpp);
1166 }
1167 }
1168 }
1169 /*
1170 * If we are over the maximum number of fragments
1171 * (due to the limit being lowered), drain off
1172 * enough to get down to the new limit.
1173 */
1174 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) {
1175 for (i = 0; i < IPREASS_NHASH; i++) {
1176 while (V_nipq > V_maxnipq &&
1177 !TAILQ_EMPTY(&V_ipq[i])) {
1178 IPSTAT_ADD(ips_fragdropped,
1179 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1180 ip_freef(&V_ipq[i],
1181 TAILQ_FIRST(&V_ipq[i]));
1182 }
1183 }
1184 }
1185 CURVNET_RESTORE();
1186 }
1187 IPQ_UNLOCK();
1188 VNET_LIST_RUNLOCK_NOSLEEP();
1189}
1190
1191/*
1192 * Drain off all datagram fragments.
1193 */
1194static void
1195ip_drain_locked(void)
1196{
1197 int i;
1198
1199 IPQ_LOCK_ASSERT();
1200
1201 for (i = 0; i < IPREASS_NHASH; i++) {
1202 while(!TAILQ_EMPTY(&V_ipq[i])) {
1203 IPSTAT_ADD(ips_fragdropped,
1204 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1205 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i]));
1206 }
1207 }
1208}
1209
1210void
1211ip_drain(void)
1212{
1213 VNET_ITERATOR_DECL(vnet_iter);
1214
1215 VNET_LIST_RLOCK_NOSLEEP();
1216 IPQ_LOCK();
1217 VNET_FOREACH(vnet_iter) {
1218 CURVNET_SET(vnet_iter);
1219 ip_drain_locked();
1220 CURVNET_RESTORE();
1221 }
1222 IPQ_UNLOCK();
1223 VNET_LIST_RUNLOCK_NOSLEEP();
1224 in_rtqdrain();
1225}
1226
1227/*
1228 * The protocol to be inserted into ip_protox[] must be already registered
1229 * in inetsw[], either statically or through pf_proto_register().
1230 */
1231int
1232ipproto_register(short ipproto)
1233{
1234 struct protosw *pr;
1235
1236 /* Sanity checks. */
1237 if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
1238 return (EPROTONOSUPPORT);
1239
1240 /*
1241 * The protocol slot must not be occupied by another protocol
1242 * already. An index pointing to IPPROTO_RAW is unused.
1243 */
1244 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1245 if (pr == NULL)
1246 return (EPFNOSUPPORT);
1247 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
1248 return (EEXIST);
1249
1250 /* Find the protocol position in inetsw[] and set the index. */
1251 for (pr = inetdomain.dom_protosw;
1252 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
1253 if (pr->pr_domain->dom_family == PF_INET &&
1254 pr->pr_protocol && pr->pr_protocol == ipproto) {
1255 ip_protox[pr->pr_protocol] = pr - inetsw;
1256 return (0);
1257 }
1258 }
1259 return (EPROTONOSUPPORT);
1260}
1261
1262int
1263ipproto_unregister(short ipproto)
1264{
1265 struct protosw *pr;
1266
1267 /* Sanity checks. */
1268 if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
1269 return (EPROTONOSUPPORT);
1270
1271 /* Check if the protocol was indeed registered. */
1272 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1273 if (pr == NULL)
1274 return (EPFNOSUPPORT);
1275 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
1276 return (ENOENT);
1277
1278 /* Reset the protocol slot to IPPROTO_RAW. */
1279 ip_protox[ipproto] = pr - inetsw;
1280 return (0);
1281}
1282
1283/*
1284 * Given address of next destination (final or next hop), return (referenced)
1285 * internet address info of interface to be used to get there.
1286 */
1287struct in_ifaddr *
1288ip_rtaddr(struct in_addr dst, u_int fibnum)
1289{
1290 struct route sro;
1291 struct sockaddr_in *sin;
1292 struct in_ifaddr *ia;
1293
1294 bzero(&sro, sizeof(sro));
1295 sin = (struct sockaddr_in *)&sro.ro_dst;
1296 sin->sin_family = AF_INET;
1297 sin->sin_len = sizeof(*sin);
1298 sin->sin_addr = dst;
1299 in_rtalloc_ign(&sro, 0, fibnum);
1300
1301 if (sro.ro_rt == NULL)
1302 return (NULL);
1303
1304 ia = ifatoia(sro.ro_rt->rt_ifa);
1305 ifa_ref(&ia->ia_ifa);
1306 RTFREE(sro.ro_rt);
1307 return (ia);
1308}
1309
1310u_char inetctlerrmap[PRC_NCMDS] = {
1311 0, 0, 0, 0,
1312 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1313 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1314 EMSGSIZE, EHOSTUNREACH, 0, 0,
1315 0, 0, EHOSTUNREACH, 0,
1316 ENOPROTOOPT, ECONNREFUSED
1317};
1318
1319/*
1320 * Forward a packet. If some error occurs return the sender
1321 * an icmp packet. Note we can't always generate a meaningful
1322 * icmp message because icmp doesn't have a large enough repertoire
1323 * of codes and types.
1324 *
1325 * If not forwarding, just drop the packet. This could be confusing
1326 * if ipforwarding was zero but some routing protocol was advancing
1327 * us as a gateway to somewhere. However, we must let the routing
1328 * protocol deal with that.
1329 *
1330 * The srcrt parameter indicates whether the packet is being forwarded
1331 * via a source route.
1332 */
1333void
1334ip_forward(struct mbuf *m, int srcrt)
1335{
1336 struct ip *ip = mtod(m, struct ip *);
1337 struct in_ifaddr *ia;
1338 struct mbuf *mcopy;
1339 struct in_addr dest;
1340 struct route ro;
1341 int error, type = 0, code = 0, mtu = 0;
1342
1343 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1344 IPSTAT_INC(ips_cantforward);
1345 m_freem(m);
1346 return;
1347 }
1348#ifdef IPSTEALTH
1349 if (!V_ipstealth) {
1350#endif
1351 if (ip->ip_ttl <= IPTTLDEC) {
1352 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
1353 0, 0);
1354 return;
1355 }
1356#ifdef IPSTEALTH
1357 }
1358#endif
1359
1360 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
1361#ifndef IPSEC
1362 /*
1363 * 'ia' may be NULL if there is no route for this destination.
1364 * In case of IPsec, Don't discard it just yet, but pass it to
1365 * ip_output in case of outgoing IPsec policy.
1366 */
1367 if (!srcrt && ia == NULL) {
1368 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
1369 return;
1370 }
1371#endif
1372
1373 /*
1374 * Save the IP header and at most 8 bytes of the payload,
1375 * in case we need to generate an ICMP message to the src.
1376 *
1377 * XXX this can be optimized a lot by saving the data in a local
1378 * buffer on the stack (72 bytes at most), and only allocating the
1379 * mbuf if really necessary. The vast majority of the packets
1380 * are forwarded without having to send an ICMP back (either
1381 * because unnecessary, or because rate limited), so we are
1382 * really we are wasting a lot of work here.
1383 *
1384 * We don't use m_copy() because it might return a reference
1385 * to a shared cluster. Both this function and ip_output()
1386 * assume exclusive access to the IP header in `m', so any
1387 * data in a cluster may change before we reach icmp_error().
1388 */
1389 mcopy = m_gethdr(M_NOWAIT, m->m_type);
1390 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) {
1391 /*
1392 * It's probably ok if the pkthdr dup fails (because
1393 * the deep copy of the tag chain failed), but for now
1394 * be conservative and just discard the copy since
1395 * code below may some day want the tags.
1396 */
1397 m_free(mcopy);
1398 mcopy = NULL;
1399 }
1400 if (mcopy != NULL) {
1401 mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy));
1402 mcopy->m_pkthdr.len = mcopy->m_len;
1403 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1404 }
1405
1406#ifdef IPSTEALTH
1407 if (!V_ipstealth) {
1408#endif
1409 ip->ip_ttl -= IPTTLDEC;
1410#ifdef IPSTEALTH
1411 }
1412#endif
1413
1414 /*
1415 * If forwarding packet using same interface that it came in on,
1416 * perhaps should send a redirect to sender to shortcut a hop.
1417 * Only send redirect if source is sending directly to us,
1418 * and if packet was not source routed (or has any options).
1419 * Also, don't send redirect if forwarding using a default route
1420 * or a route modified by a redirect.
1421 */
1422 dest.s_addr = 0;
1423 if (!srcrt && V_ipsendredirects &&
1424 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
1425 struct sockaddr_in *sin;
1426 struct rtentry *rt;
1427
1428 bzero(&ro, sizeof(ro));
1429 sin = (struct sockaddr_in *)&ro.ro_dst;
1430 sin->sin_family = AF_INET;
1431 sin->sin_len = sizeof(*sin);
1432 sin->sin_addr = ip->ip_dst;
1433 in_rtalloc_ign(&ro, 0, M_GETFIB(m));
1434
1435 rt = ro.ro_rt;
1436
1437 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1438 satosin(rt_key(rt))->sin_addr.s_addr != 0) {
1439#define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1440 u_long src = ntohl(ip->ip_src.s_addr);
1441
1442 if (RTA(rt) &&
1443 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1444 if (rt->rt_flags & RTF_GATEWAY)
1445 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
1446 else
1447 dest.s_addr = ip->ip_dst.s_addr;
1448 /* Router requirements says to only send host redirects */
1449 type = ICMP_REDIRECT;
1450 code = ICMP_REDIRECT_HOST;
1451 }
1452 }
1453 if (rt)
1454 RTFREE(rt);
1455 }
1456
1457 /*
1458 * Try to cache the route MTU from ip_output so we can consider it for
1459 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191.
1460 */
1461 bzero(&ro, sizeof(ro));
1462
1463 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
1464
1465 if (error == EMSGSIZE && ro.ro_rt)
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