1 /*-
2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD: releng/8.1/sys/netinet/ip_input.c 207695 2010-05-06 06:44:19Z bz $");
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 #include "opt_carp.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/callout.h>
45 #include <sys/mbuf.h>
46 #include <sys/malloc.h>
47 #include <sys/domain.h>
48 #include <sys/protosw.h>
49 #include <sys/socket.h>
50 #include <sys/time.h>
51 #include <sys/kernel.h>
52 #include <sys/lock.h>
53 #include <sys/rwlock.h>
54 #include <sys/syslog.h>
55 #include <sys/sysctl.h>
56
57 #include <net/pfil.h>
58 #include <net/if.h>
59 #include <net/if_types.h>
60 #include <net/if_var.h>
61 #include <net/if_dl.h>
62 #include <net/route.h>
63 #include <net/netisr.h>
64 #include <net/vnet.h>
65 #include <net/flowtable.h>
66
67 #include <netinet/in.h>
68 #include <netinet/in_systm.h>
69 #include <netinet/in_var.h>
70 #include <netinet/ip.h>
71 #include <netinet/in_pcb.h>
72 #include <netinet/ip_var.h>
73 #include <netinet/ip_fw.h>
74 #include <netinet/ip_icmp.h>
75 #include <netinet/ip_options.h>
76 #include <machine/in_cksum.h>
77 #ifdef DEV_CARP
78 #include <netinet/ip_carp.h>
79 #endif
80 #ifdef IPSEC
81 #include <netinet/ip_ipsec.h>
82 #endif /* IPSEC */
83
84 #include <sys/socketvar.h>
85
86 #include <security/mac/mac_framework.h>
87
88 #ifdef CTASSERT
89 CTASSERT(sizeof(struct ip) == 20);
90 #endif
91
92 struct rwlock in_ifaddr_lock;
93 RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock");
94
95 VNET_DEFINE(int, rsvp_on);
96
97 VNET_DEFINE(int, ipforwarding);
98 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
99 &VNET_NAME(ipforwarding), 0,
100 "Enable IP forwarding between interfaces");
101
102 static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */
103 #define V_ipsendredirects VNET(ipsendredirects)
104 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
105 &VNET_NAME(ipsendredirects), 0,
106 "Enable sending IP redirects");
107
108 VNET_DEFINE(int, ip_defttl) = IPDEFTTL;
109 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
110 &VNET_NAME(ip_defttl), 0,
111 "Maximum TTL on IP packets");
112
113 static VNET_DEFINE(int, ip_keepfaith);
114 #define V_ip_keepfaith VNET(ip_keepfaith)
115 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
116 &VNET_NAME(ip_keepfaith), 0,
117 "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
118
119 static VNET_DEFINE(int, ip_sendsourcequench);
120 #define V_ip_sendsourcequench VNET(ip_sendsourcequench)
121 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
122 &VNET_NAME(ip_sendsourcequench), 0,
123 "Enable the transmission of source quench packets");
124
125 VNET_DEFINE(int, ip_do_randomid);
126 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
127 &VNET_NAME(ip_do_randomid), 0,
128 "Assign random ip_id values");
129
130 /*
131 * XXX - Setting ip_checkinterface mostly implements the receive side of
132 * the Strong ES model described in RFC 1122, but since the routing table
133 * and transmit implementation do not implement the Strong ES model,
134 * setting this to 1 results in an odd hybrid.
135 *
136 * XXX - ip_checkinterface currently must be disabled if you use ipnat
137 * to translate the destination address to another local interface.
138 *
139 * XXX - ip_checkinterface must be disabled if you add IP aliases
140 * to the loopback interface instead of the interface where the
141 * packets for those addresses are received.
142 */
143 static VNET_DEFINE(int, ip_checkinterface);
144 #define V_ip_checkinterface VNET(ip_checkinterface)
145 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
146 &VNET_NAME(ip_checkinterface), 0,
147 "Verify packet arrives on correct interface");
148
149 VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */
150
151 static struct netisr_handler ip_nh = {
152 .nh_name = "ip",
153 .nh_handler = ip_input,
154 .nh_proto = NETISR_IP,
155 .nh_policy = NETISR_POLICY_FLOW,
156 };
157
158 extern struct domain inetdomain;
159 extern struct protosw inetsw[];
160 u_char ip_protox[IPPROTO_MAX];
161 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */
162 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */
163 VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */
164
165 VNET_DEFINE(struct ipstat, ipstat);
166 SYSCTL_VNET_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
167 &VNET_NAME(ipstat), ipstat,
168 "IP statistics (struct ipstat, netinet/ip_var.h)");
169
170 static VNET_DEFINE(uma_zone_t, ipq_zone);
171 static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]);
172 static struct mtx ipqlock;
173
174 #define V_ipq_zone VNET(ipq_zone)
175 #define V_ipq VNET(ipq)
176
177 #define IPQ_LOCK() mtx_lock(&ipqlock)
178 #define IPQ_UNLOCK() mtx_unlock(&ipqlock)
179 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
180 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
181
182 static void maxnipq_update(void);
183 static void ipq_zone_change(void *);
184 static void ip_drain_locked(void);
185
186 static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */
187 static VNET_DEFINE(int, nipq); /* Total # of reass queues */
188 #define V_maxnipq VNET(maxnipq)
189 #define V_nipq VNET(nipq)
190 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD,
191 &VNET_NAME(nipq), 0,
192 "Current number of IPv4 fragment reassembly queue entries");
193
194 static VNET_DEFINE(int, maxfragsperpacket);
195 #define V_maxfragsperpacket VNET(maxfragsperpacket)
196 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
197 &VNET_NAME(maxfragsperpacket), 0,
198 "Maximum number of IPv4 fragments allowed per packet");
199
200 struct callout ipport_tick_callout;
201
202 #ifdef IPCTL_DEFMTU
203 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
204 &ip_mtu, 0, "Default MTU");
205 #endif
206
207 #ifdef IPSTEALTH
208 VNET_DEFINE(int, ipstealth);
209 SYSCTL_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
215 static VNET_DEFINE(int, ip_output_flowtable_size) = 2048;
216 VNET_DEFINE(struct flowtable *, ip_ft);
217 #define V_ip_output_flowtable_size VNET(ip_output_flowtable_size)
218
219 SYSCTL_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
224 VNET_DEFINE(int, fw_one_pass) = 1;
225
226 static 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 */
235 void
236 kmod_ipstat_inc(int statnum)
237 {
238
239 (*((u_long *)&V_ipstat + statnum))++;
240 }
241
242 void
243 kmod_ipstat_dec(int statnum)
244 {
245
246 (*((u_long *)&V_ipstat + statnum))--;
247 }
248
249 static int
250 sysctl_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 }
262 SYSCTL_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
266 static int
267 sysctl_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
283 SYSCTL_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 */
291 void
292 ip_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
374 void
375 ip_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
389 void
390 ip_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 */
400 void
401 ip_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) {
503 tooshort:
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
560 passin:
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
739 ours:
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;
795 bad:
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 */
804 static void
805 maxnipq_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
827 static void
828 ipq_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
837 static int
838 sysctl_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
858 SYSCTL_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 */
872 struct mbuf *
873 ip_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
940 found:
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
1171 dropfrag:
1172 IPSTAT_INC(ips_fragdropped);
1173 if (fp != NULL)
1174 fp->ipq_nfrags--;
1175 m_freem(m);
1176 done:
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 */
1187 static void
1188 ip_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 */
1209 void
1210 ip_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 */
1258 static void
1259 ip_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
1274 void
1275 ip_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 */
1295 int
1296 ipproto_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
1330 int
1331 ipproto_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 */
1355 struct in_ifaddr *
1356 ip_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
1378 u_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 */
1401 void
1402 ip_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
1634 void
1635 ip_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 {
1712 makedummy:
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 */
1732 static VNET_DEFINE(int, ip_rsvp_on);
1733 VNET_DEFINE(struct socket *, ip_rsvpd);
1734
1735 #define V_ip_rsvp_on VNET(ip_rsvp_on)
1736
1737 int
1738 ip_rsvp_init(struct socket *so)
1739 {
1740
1741 if (so->so_type != SOCK_RAW ||
1742 so->so_proto->pr_protocol != IPPROTO_RSVP)
1743 return EOPNOTSUPP;
1744
1745 if (V_ip_rsvpd != NULL)
1746 return EADDRINUSE;
1747
1748 V_ip_rsvpd = so;
1749 /*
1750 * This may seem silly, but we need to be sure we don't over-increment
1751 * the RSVP counter, in case something slips up.
1752 */
1753 if (!V_ip_rsvp_on) {
1754 V_ip_rsvp_on = 1;
1755 V_rsvp_on++;
1756 }
1757
1758 return 0;
1759 }
1760
1761 int
1762 ip_rsvp_done(void)
1763 {
1764
1765 V_ip_rsvpd = NULL;
1766 /*
1767 * This may seem silly, but we need to be sure we don't over-decrement
1768 * the RSVP counter, in case something slips up.
1769 */
1770 if (V_ip_rsvp_on) {
1771 V_ip_rsvp_on = 0;
1772 V_rsvp_on--;
1773 }
1774 return 0;
1775 }
1776
1777 void
1778 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */
1779 {
1780
1781 if (rsvp_input_p) { /* call the real one if loaded */
1782 rsvp_input_p(m, off);
1783 return;
1784 }
1785
1786 /* Can still get packets with rsvp_on = 0 if there is a local member
1787 * of the group to which the RSVP packet is addressed. But in this
1788 * case we want to throw the packet away.
1789 */
1790
1791 if (!V_rsvp_on) {
1792 m_freem(m);
1793 return;
1794 }
1795
1796 if (V_ip_rsvpd != NULL) {
1797 rip_input(m, off);
1798 return;
1799 }
1800 /* Drop the packet */
1801 m_freem(m);
1802 }
Cache object: cd8c6ce059f56a6aa3caccef8d515c6e
|