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/9.0/sys/netinet/ip_input.c 226572 2011-10-20 15:58:05Z glebius $");
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/syslog.h>
53 #include <sys/sysctl.h>
54
55 #include <net/pfil.h>
56 #include <net/if.h>
57 #include <net/if_types.h>
58 #include <net/if_var.h>
59 #include <net/if_dl.h>
60 #include <net/route.h>
61 #include <net/netisr.h>
62 #include <net/vnet.h>
63 #include <net/flowtable.h>
64
65 #include <netinet/in.h>
66 #include <netinet/in_systm.h>
67 #include <netinet/in_var.h>
68 #include <netinet/ip.h>
69 #include <netinet/in_pcb.h>
70 #include <netinet/ip_var.h>
71 #include <netinet/ip_fw.h>
72 #include <netinet/ip_icmp.h>
73 #include <netinet/ip_options.h>
74 #include <machine/in_cksum.h>
75 #include <netinet/ip_carp.h>
76 #ifdef IPSEC
77 #include <netinet/ip_ipsec.h>
78 #endif /* IPSEC */
79
80 #include <sys/socketvar.h>
81
82 #include <security/mac/mac_framework.h>
83
84 #ifdef CTASSERT
85 CTASSERT(sizeof(struct ip) == 20);
86 #endif
87
88 struct rwlock in_ifaddr_lock;
89 RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock");
90
91 VNET_DEFINE(int, rsvp_on);
92
93 VNET_DEFINE(int, ipforwarding);
94 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
95 &VNET_NAME(ipforwarding), 0,
96 "Enable IP forwarding between interfaces");
97
98 static VNET_DEFINE(int, ipsendredirects) = 1; /* XXX */
99 #define V_ipsendredirects VNET(ipsendredirects)
100 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
101 &VNET_NAME(ipsendredirects), 0,
102 "Enable sending IP redirects");
103
104 static VNET_DEFINE(int, ip_keepfaith);
105 #define V_ip_keepfaith VNET(ip_keepfaith)
106 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
107 &VNET_NAME(ip_keepfaith), 0,
108 "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
109
110 static VNET_DEFINE(int, ip_sendsourcequench);
111 #define V_ip_sendsourcequench VNET(ip_sendsourcequench)
112 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
113 &VNET_NAME(ip_sendsourcequench), 0,
114 "Enable the transmission of source quench packets");
115
116 VNET_DEFINE(int, ip_do_randomid);
117 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
118 &VNET_NAME(ip_do_randomid), 0,
119 "Assign random ip_id values");
120
121 /*
122 * XXX - Setting ip_checkinterface mostly implements the receive side of
123 * the Strong ES model described in RFC 1122, but since the routing table
124 * and transmit implementation do not implement the Strong ES model,
125 * setting this to 1 results in an odd hybrid.
126 *
127 * XXX - ip_checkinterface currently must be disabled if you use ipnat
128 * to translate the destination address to another local interface.
129 *
130 * XXX - ip_checkinterface must be disabled if you add IP aliases
131 * to the loopback interface instead of the interface where the
132 * packets for those addresses are received.
133 */
134 static VNET_DEFINE(int, ip_checkinterface);
135 #define V_ip_checkinterface VNET(ip_checkinterface)
136 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
137 &VNET_NAME(ip_checkinterface), 0,
138 "Verify packet arrives on correct interface");
139
140 VNET_DEFINE(struct pfil_head, inet_pfil_hook); /* Packet filter hooks */
141
142 static struct netisr_handler ip_nh = {
143 .nh_name = "ip",
144 .nh_handler = ip_input,
145 .nh_proto = NETISR_IP,
146 .nh_policy = NETISR_POLICY_FLOW,
147 };
148
149 extern struct domain inetdomain;
150 extern struct protosw inetsw[];
151 u_char ip_protox[IPPROTO_MAX];
152 VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */
153 VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */
154 VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */
155
156 VNET_DEFINE(struct ipstat, ipstat);
157 SYSCTL_VNET_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
158 &VNET_NAME(ipstat), ipstat,
159 "IP statistics (struct ipstat, netinet/ip_var.h)");
160
161 static VNET_DEFINE(uma_zone_t, ipq_zone);
162 static VNET_DEFINE(TAILQ_HEAD(ipqhead, ipq), ipq[IPREASS_NHASH]);
163 static struct mtx ipqlock;
164
165 #define V_ipq_zone VNET(ipq_zone)
166 #define V_ipq VNET(ipq)
167
168 #define IPQ_LOCK() mtx_lock(&ipqlock)
169 #define IPQ_UNLOCK() mtx_unlock(&ipqlock)
170 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
171 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
172
173 static void maxnipq_update(void);
174 static void ipq_zone_change(void *);
175 static void ip_drain_locked(void);
176
177 static VNET_DEFINE(int, maxnipq); /* Administrative limit on # reass queues. */
178 static VNET_DEFINE(int, nipq); /* Total # of reass queues */
179 #define V_maxnipq VNET(maxnipq)
180 #define V_nipq VNET(nipq)
181 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD,
182 &VNET_NAME(nipq), 0,
183 "Current number of IPv4 fragment reassembly queue entries");
184
185 static VNET_DEFINE(int, maxfragsperpacket);
186 #define V_maxfragsperpacket VNET(maxfragsperpacket)
187 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
188 &VNET_NAME(maxfragsperpacket), 0,
189 "Maximum number of IPv4 fragments allowed per packet");
190
191 #ifdef IPCTL_DEFMTU
192 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
193 &ip_mtu, 0, "Default MTU");
194 #endif
195
196 #ifdef IPSTEALTH
197 VNET_DEFINE(int, ipstealth);
198 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
199 &VNET_NAME(ipstealth), 0,
200 "IP stealth mode, no TTL decrementation on forwarding");
201 #endif
202
203 #ifdef FLOWTABLE
204 static VNET_DEFINE(int, ip_output_flowtable_size) = 2048;
205 VNET_DEFINE(struct flowtable *, ip_ft);
206 #define V_ip_output_flowtable_size VNET(ip_output_flowtable_size)
207
208 SYSCTL_VNET_INT(_net_inet_ip, OID_AUTO, output_flowtable_size, CTLFLAG_RDTUN,
209 &VNET_NAME(ip_output_flowtable_size), 2048,
210 "number of entries in the per-cpu output flow caches");
211 #endif
212
213 static void ip_freef(struct ipqhead *, struct ipq *);
214
215 /*
216 * Kernel module interface for updating ipstat. The argument is an index
217 * into ipstat treated as an array of u_long. While this encodes the general
218 * layout of ipstat into the caller, it doesn't encode its location, so that
219 * future changes to add, for example, per-CPU stats support won't cause
220 * binary compatibility problems for kernel modules.
221 */
222 void
223 kmod_ipstat_inc(int statnum)
224 {
225
226 (*((u_long *)&V_ipstat + statnum))++;
227 }
228
229 void
230 kmod_ipstat_dec(int statnum)
231 {
232
233 (*((u_long *)&V_ipstat + statnum))--;
234 }
235
236 static int
237 sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
238 {
239 int error, qlimit;
240
241 netisr_getqlimit(&ip_nh, &qlimit);
242 error = sysctl_handle_int(oidp, &qlimit, 0, req);
243 if (error || !req->newptr)
244 return (error);
245 if (qlimit < 1)
246 return (EINVAL);
247 return (netisr_setqlimit(&ip_nh, qlimit));
248 }
249 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
250 CTLTYPE_INT|CTLFLAG_RW, 0, 0, sysctl_netinet_intr_queue_maxlen, "I",
251 "Maximum size of the IP input queue");
252
253 static int
254 sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
255 {
256 u_int64_t qdrops_long;
257 int error, qdrops;
258
259 netisr_getqdrops(&ip_nh, &qdrops_long);
260 qdrops = qdrops_long;
261 error = sysctl_handle_int(oidp, &qdrops, 0, req);
262 if (error || !req->newptr)
263 return (error);
264 if (qdrops != 0)
265 return (EINVAL);
266 netisr_clearqdrops(&ip_nh);
267 return (0);
268 }
269
270 SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
271 CTLTYPE_INT|CTLFLAG_RD, 0, 0, sysctl_netinet_intr_queue_drops, "I",
272 "Number of packets dropped from the IP input queue");
273
274 /*
275 * IP initialization: fill in IP protocol switch table.
276 * All protocols not implemented in kernel go to raw IP protocol handler.
277 */
278 void
279 ip_init(void)
280 {
281 struct protosw *pr;
282 int i;
283
284 V_ip_id = time_second & 0xffff;
285
286 TAILQ_INIT(&V_in_ifaddrhead);
287 V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);
288
289 /* Initialize IP reassembly queue. */
290 for (i = 0; i < IPREASS_NHASH; i++)
291 TAILQ_INIT(&V_ipq[i]);
292 V_maxnipq = nmbclusters / 32;
293 V_maxfragsperpacket = 16;
294 V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
295 NULL, UMA_ALIGN_PTR, 0);
296 maxnipq_update();
297
298 /* Initialize packet filter hooks. */
299 V_inet_pfil_hook.ph_type = PFIL_TYPE_AF;
300 V_inet_pfil_hook.ph_af = AF_INET;
301 if ((i = pfil_head_register(&V_inet_pfil_hook)) != 0)
302 printf("%s: WARNING: unable to register pfil hook, "
303 "error %d\n", __func__, i);
304
305 #ifdef FLOWTABLE
306 if (TUNABLE_INT_FETCH("net.inet.ip.output_flowtable_size",
307 &V_ip_output_flowtable_size)) {
308 if (V_ip_output_flowtable_size < 256)
309 V_ip_output_flowtable_size = 256;
310 if (!powerof2(V_ip_output_flowtable_size)) {
311 printf("flowtable must be power of 2 size\n");
312 V_ip_output_flowtable_size = 2048;
313 }
314 } else {
315 /*
316 * round up to the next power of 2
317 */
318 V_ip_output_flowtable_size = 1 << fls((1024 + maxusers * 64)-1);
319 }
320 V_ip_ft = flowtable_alloc("ipv4", V_ip_output_flowtable_size, FL_PCPU);
321 #endif
322
323 /* Skip initialization of globals for non-default instances. */
324 if (!IS_DEFAULT_VNET(curvnet))
325 return;
326
327 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
328 if (pr == NULL)
329 panic("ip_init: PF_INET not found");
330
331 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
332 for (i = 0; i < IPPROTO_MAX; i++)
333 ip_protox[i] = pr - inetsw;
334 /*
335 * Cycle through IP protocols and put them into the appropriate place
336 * in ip_protox[].
337 */
338 for (pr = inetdomain.dom_protosw;
339 pr < inetdomain.dom_protoswNPROTOSW; pr++)
340 if (pr->pr_domain->dom_family == PF_INET &&
341 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
342 /* Be careful to only index valid IP protocols. */
343 if (pr->pr_protocol < IPPROTO_MAX)
344 ip_protox[pr->pr_protocol] = pr - inetsw;
345 }
346
347 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change,
348 NULL, EVENTHANDLER_PRI_ANY);
349
350 /* Initialize various other remaining things. */
351 IPQ_LOCK_INIT();
352 netisr_register(&ip_nh);
353 }
354
355 #ifdef VIMAGE
356 void
357 ip_destroy(void)
358 {
359
360 /* Cleanup in_ifaddr hash table; should be empty. */
361 hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
362
363 IPQ_LOCK();
364 ip_drain_locked();
365 IPQ_UNLOCK();
366
367 uma_zdestroy(V_ipq_zone);
368 }
369 #endif
370
371 /*
372 * Ip input routine. Checksum and byte swap header. If fragmented
373 * try to reassemble. Process options. Pass to next level.
374 */
375 void
376 ip_input(struct mbuf *m)
377 {
378 struct ip *ip = NULL;
379 struct in_ifaddr *ia = NULL;
380 struct ifaddr *ifa;
381 struct ifnet *ifp;
382 int checkif, hlen = 0;
383 u_short sum;
384 int dchg = 0; /* dest changed after fw */
385 struct in_addr odst; /* original dst address */
386
387 M_ASSERTPKTHDR(m);
388
389 if (m->m_flags & M_FASTFWD_OURS) {
390 /*
391 * Firewall or NAT changed destination to local.
392 * We expect ip_len and ip_off to be in host byte order.
393 */
394 m->m_flags &= ~M_FASTFWD_OURS;
395 /* Set up some basics that will be used later. */
396 ip = mtod(m, struct ip *);
397 hlen = ip->ip_hl << 2;
398 goto ours;
399 }
400
401 IPSTAT_INC(ips_total);
402
403 if (m->m_pkthdr.len < sizeof(struct ip))
404 goto tooshort;
405
406 if (m->m_len < sizeof (struct ip) &&
407 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
408 IPSTAT_INC(ips_toosmall);
409 return;
410 }
411 ip = mtod(m, struct ip *);
412
413 if (ip->ip_v != IPVERSION) {
414 IPSTAT_INC(ips_badvers);
415 goto bad;
416 }
417
418 hlen = ip->ip_hl << 2;
419 if (hlen < sizeof(struct ip)) { /* minimum header length */
420 IPSTAT_INC(ips_badhlen);
421 goto bad;
422 }
423 if (hlen > m->m_len) {
424 if ((m = m_pullup(m, hlen)) == NULL) {
425 IPSTAT_INC(ips_badhlen);
426 return;
427 }
428 ip = mtod(m, struct ip *);
429 }
430
431 /* 127/8 must not appear on wire - RFC1122 */
432 ifp = m->m_pkthdr.rcvif;
433 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
434 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
435 if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
436 IPSTAT_INC(ips_badaddr);
437 goto bad;
438 }
439 }
440
441 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
442 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
443 } else {
444 if (hlen == sizeof(struct ip)) {
445 sum = in_cksum_hdr(ip);
446 } else {
447 sum = in_cksum(m, hlen);
448 }
449 }
450 if (sum) {
451 IPSTAT_INC(ips_badsum);
452 goto bad;
453 }
454
455 #ifdef ALTQ
456 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
457 /* packet is dropped by traffic conditioner */
458 return;
459 #endif
460
461 /*
462 * Convert fields to host representation.
463 */
464 ip->ip_len = ntohs(ip->ip_len);
465 if (ip->ip_len < hlen) {
466 IPSTAT_INC(ips_badlen);
467 goto bad;
468 }
469 ip->ip_off = ntohs(ip->ip_off);
470
471 /*
472 * Check that the amount of data in the buffers
473 * is as at least much as the IP header would have us expect.
474 * Trim mbufs if longer than we expect.
475 * Drop packet if shorter than we expect.
476 */
477 if (m->m_pkthdr.len < ip->ip_len) {
478 tooshort:
479 IPSTAT_INC(ips_tooshort);
480 goto bad;
481 }
482 if (m->m_pkthdr.len > ip->ip_len) {
483 if (m->m_len == m->m_pkthdr.len) {
484 m->m_len = ip->ip_len;
485 m->m_pkthdr.len = ip->ip_len;
486 } else
487 m_adj(m, ip->ip_len - m->m_pkthdr.len);
488 }
489 #ifdef IPSEC
490 /*
491 * Bypass packet filtering for packets previously handled by IPsec.
492 */
493 if (ip_ipsec_filtertunnel(m))
494 goto passin;
495 #endif /* IPSEC */
496
497 /*
498 * Run through list of hooks for input packets.
499 *
500 * NB: Beware of the destination address changing (e.g.
501 * by NAT rewriting). When this happens, tell
502 * ip_forward to do the right thing.
503 */
504
505 /* Jump over all PFIL processing if hooks are not active. */
506 if (!PFIL_HOOKED(&V_inet_pfil_hook))
507 goto passin;
508
509 odst = ip->ip_dst;
510 if (pfil_run_hooks(&V_inet_pfil_hook, &m, ifp, PFIL_IN, NULL) != 0)
511 return;
512 if (m == NULL) /* consumed by filter */
513 return;
514
515 ip = mtod(m, struct ip *);
516 dchg = (odst.s_addr != ip->ip_dst.s_addr);
517 ifp = m->m_pkthdr.rcvif;
518
519 #ifdef IPFIREWALL_FORWARD
520 if (m->m_flags & M_FASTFWD_OURS) {
521 m->m_flags &= ~M_FASTFWD_OURS;
522 goto ours;
523 }
524 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) {
525 /*
526 * Directly ship the packet on. This allows forwarding
527 * packets originally destined to us to some other directly
528 * connected host.
529 */
530 ip_forward(m, dchg);
531 return;
532 }
533 #endif /* IPFIREWALL_FORWARD */
534
535 passin:
536 /*
537 * Process options and, if not destined for us,
538 * ship it on. ip_dooptions returns 1 when an
539 * error was detected (causing an icmp message
540 * to be sent and the original packet to be freed).
541 */
542 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
543 return;
544
545 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
546 * matter if it is destined to another node, or whether it is
547 * a multicast one, RSVP wants it! and prevents it from being forwarded
548 * anywhere else. Also checks if the rsvp daemon is running before
549 * grabbing the packet.
550 */
551 if (V_rsvp_on && ip->ip_p==IPPROTO_RSVP)
552 goto ours;
553
554 /*
555 * Check our list of addresses, to see if the packet is for us.
556 * If we don't have any addresses, assume any unicast packet
557 * we receive might be for us (and let the upper layers deal
558 * with it).
559 */
560 if (TAILQ_EMPTY(&V_in_ifaddrhead) &&
561 (m->m_flags & (M_MCAST|M_BCAST)) == 0)
562 goto ours;
563
564 /*
565 * Enable a consistency check between the destination address
566 * and the arrival interface for a unicast packet (the RFC 1122
567 * strong ES model) if IP forwarding is disabled and the packet
568 * is not locally generated and the packet is not subject to
569 * 'ipfw fwd'.
570 *
571 * XXX - Checking also should be disabled if the destination
572 * address is ipnat'ed to a different interface.
573 *
574 * XXX - Checking is incompatible with IP aliases added
575 * to the loopback interface instead of the interface where
576 * the packets are received.
577 *
578 * XXX - This is the case for carp vhost IPs as well so we
579 * insert a workaround. If the packet got here, we already
580 * checked with carp_iamatch() and carp_forus().
581 */
582 checkif = V_ip_checkinterface && (V_ipforwarding == 0) &&
583 ifp != NULL && ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
584 ifp->if_carp == NULL && (dchg == 0);
585
586 /*
587 * Check for exact addresses in the hash bucket.
588 */
589 /* IN_IFADDR_RLOCK(); */
590 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
591 /*
592 * If the address matches, verify that the packet
593 * arrived via the correct interface if checking is
594 * enabled.
595 */
596 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
597 (!checkif || ia->ia_ifp == ifp)) {
598 ifa_ref(&ia->ia_ifa);
599 /* IN_IFADDR_RUNLOCK(); */
600 goto ours;
601 }
602 }
603 /* IN_IFADDR_RUNLOCK(); */
604
605 /*
606 * Check for broadcast addresses.
607 *
608 * Only accept broadcast packets that arrive via the matching
609 * interface. Reception of forwarded directed broadcasts would
610 * be handled via ip_forward() and ether_output() with the loopback
611 * into the stack for SIMPLEX interfaces handled by ether_output().
612 */
613 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
614 IF_ADDR_LOCK(ifp);
615 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
616 if (ifa->ifa_addr->sa_family != AF_INET)
617 continue;
618 ia = ifatoia(ifa);
619 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
620 ip->ip_dst.s_addr) {
621 ifa_ref(ifa);
622 IF_ADDR_UNLOCK(ifp);
623 goto ours;
624 }
625 #ifdef BOOTP_COMPAT
626 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
627 ifa_ref(ifa);
628 IF_ADDR_UNLOCK(ifp);
629 goto ours;
630 }
631 #endif
632 }
633 IF_ADDR_UNLOCK(ifp);
634 ia = NULL;
635 }
636 /* RFC 3927 2.7: Do not forward datagrams for 169.254.0.0/16. */
637 if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr))) {
638 IPSTAT_INC(ips_cantforward);
639 m_freem(m);
640 return;
641 }
642 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
643 if (V_ip_mrouter) {
644 /*
645 * If we are acting as a multicast router, all
646 * incoming multicast packets are passed to the
647 * kernel-level multicast forwarding function.
648 * The packet is returned (relatively) intact; if
649 * ip_mforward() returns a non-zero value, the packet
650 * must be discarded, else it may be accepted below.
651 */
652 if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
653 IPSTAT_INC(ips_cantforward);
654 m_freem(m);
655 return;
656 }
657
658 /*
659 * The process-level routing daemon needs to receive
660 * all multicast IGMP packets, whether or not this
661 * host belongs to their destination groups.
662 */
663 if (ip->ip_p == IPPROTO_IGMP)
664 goto ours;
665 IPSTAT_INC(ips_forward);
666 }
667 /*
668 * Assume the packet is for us, to avoid prematurely taking
669 * a lock on the in_multi hash. Protocols must perform
670 * their own filtering and update statistics accordingly.
671 */
672 goto ours;
673 }
674 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
675 goto ours;
676 if (ip->ip_dst.s_addr == INADDR_ANY)
677 goto ours;
678
679 /*
680 * FAITH(Firewall Aided Internet Translator)
681 */
682 if (ifp && ifp->if_type == IFT_FAITH) {
683 if (V_ip_keepfaith) {
684 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
685 goto ours;
686 }
687 m_freem(m);
688 return;
689 }
690
691 /*
692 * Not for us; forward if possible and desirable.
693 */
694 if (V_ipforwarding == 0) {
695 IPSTAT_INC(ips_cantforward);
696 m_freem(m);
697 } else {
698 #ifdef IPSEC
699 if (ip_ipsec_fwd(m))
700 goto bad;
701 #endif /* IPSEC */
702 ip_forward(m, dchg);
703 }
704 return;
705
706 ours:
707 #ifdef IPSTEALTH
708 /*
709 * IPSTEALTH: Process non-routing options only
710 * if the packet is destined for us.
711 */
712 if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1)) {
713 if (ia != NULL)
714 ifa_free(&ia->ia_ifa);
715 return;
716 }
717 #endif /* IPSTEALTH */
718
719 /* Count the packet in the ip address stats */
720 if (ia != NULL) {
721 ia->ia_ifa.if_ipackets++;
722 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
723 ifa_free(&ia->ia_ifa);
724 }
725
726 /*
727 * Attempt reassembly; if it succeeds, proceed.
728 * ip_reass() will return a different mbuf.
729 */
730 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
731 m = ip_reass(m);
732 if (m == NULL)
733 return;
734 ip = mtod(m, struct ip *);
735 /* Get the header length of the reassembled packet */
736 hlen = ip->ip_hl << 2;
737 }
738
739 /*
740 * Further protocols expect the packet length to be w/o the
741 * IP header.
742 */
743 ip->ip_len -= hlen;
744
745 #ifdef IPSEC
746 /*
747 * enforce IPsec policy checking if we are seeing last header.
748 * note that we do not visit this with protocols with pcb layer
749 * code - like udp/tcp/raw ip.
750 */
751 if (ip_ipsec_input(m))
752 goto bad;
753 #endif /* IPSEC */
754
755 /*
756 * Switch out to protocol's input routine.
757 */
758 IPSTAT_INC(ips_delivered);
759
760 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
761 return;
762 bad:
763 m_freem(m);
764 }
765
766 /*
767 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
768 * max has slightly different semantics than the sysctl, for historical
769 * reasons.
770 */
771 static void
772 maxnipq_update(void)
773 {
774
775 /*
776 * -1 for unlimited allocation.
777 */
778 if (V_maxnipq < 0)
779 uma_zone_set_max(V_ipq_zone, 0);
780 /*
781 * Positive number for specific bound.
782 */
783 if (V_maxnipq > 0)
784 uma_zone_set_max(V_ipq_zone, V_maxnipq);
785 /*
786 * Zero specifies no further fragment queue allocation -- set the
787 * bound very low, but rely on implementation elsewhere to actually
788 * prevent allocation and reclaim current queues.
789 */
790 if (V_maxnipq == 0)
791 uma_zone_set_max(V_ipq_zone, 1);
792 }
793
794 static void
795 ipq_zone_change(void *tag)
796 {
797
798 if (V_maxnipq > 0 && V_maxnipq < (nmbclusters / 32)) {
799 V_maxnipq = nmbclusters / 32;
800 maxnipq_update();
801 }
802 }
803
804 static int
805 sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
806 {
807 int error, i;
808
809 i = V_maxnipq;
810 error = sysctl_handle_int(oidp, &i, 0, req);
811 if (error || !req->newptr)
812 return (error);
813
814 /*
815 * XXXRW: Might be a good idea to sanity check the argument and place
816 * an extreme upper bound.
817 */
818 if (i < -1)
819 return (EINVAL);
820 V_maxnipq = i;
821 maxnipq_update();
822 return (0);
823 }
824
825 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
826 NULL, 0, sysctl_maxnipq, "I",
827 "Maximum number of IPv4 fragment reassembly queue entries");
828
829 /*
830 * Take incoming datagram fragment and try to reassemble it into
831 * whole datagram. If the argument is the first fragment or one
832 * in between the function will return NULL and store the mbuf
833 * in the fragment chain. If the argument is the last fragment
834 * the packet will be reassembled and the pointer to the new
835 * mbuf returned for further processing. Only m_tags attached
836 * to the first packet/fragment are preserved.
837 * The IP header is *NOT* adjusted out of iplen.
838 */
839 struct mbuf *
840 ip_reass(struct mbuf *m)
841 {
842 struct ip *ip;
843 struct mbuf *p, *q, *nq, *t;
844 struct ipq *fp = NULL;
845 struct ipqhead *head;
846 int i, hlen, next;
847 u_int8_t ecn, ecn0;
848 u_short hash;
849
850 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
851 if (V_maxnipq == 0 || V_maxfragsperpacket == 0) {
852 IPSTAT_INC(ips_fragments);
853 IPSTAT_INC(ips_fragdropped);
854 m_freem(m);
855 return (NULL);
856 }
857
858 ip = mtod(m, struct ip *);
859 hlen = ip->ip_hl << 2;
860
861 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
862 head = &V_ipq[hash];
863 IPQ_LOCK();
864
865 /*
866 * Look for queue of fragments
867 * of this datagram.
868 */
869 TAILQ_FOREACH(fp, head, ipq_list)
870 if (ip->ip_id == fp->ipq_id &&
871 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
872 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
873 #ifdef MAC
874 mac_ipq_match(m, fp) &&
875 #endif
876 ip->ip_p == fp->ipq_p)
877 goto found;
878
879 fp = NULL;
880
881 /*
882 * Attempt to trim the number of allocated fragment queues if it
883 * exceeds the administrative limit.
884 */
885 if ((V_nipq > V_maxnipq) && (V_maxnipq > 0)) {
886 /*
887 * drop something from the tail of the current queue
888 * before proceeding further
889 */
890 struct ipq *q = TAILQ_LAST(head, ipqhead);
891 if (q == NULL) { /* gak */
892 for (i = 0; i < IPREASS_NHASH; i++) {
893 struct ipq *r = TAILQ_LAST(&V_ipq[i], ipqhead);
894 if (r) {
895 IPSTAT_ADD(ips_fragtimeout,
896 r->ipq_nfrags);
897 ip_freef(&V_ipq[i], r);
898 break;
899 }
900 }
901 } else {
902 IPSTAT_ADD(ips_fragtimeout, q->ipq_nfrags);
903 ip_freef(head, q);
904 }
905 }
906
907 found:
908 /*
909 * Adjust ip_len to not reflect header,
910 * convert offset of this to bytes.
911 */
912 ip->ip_len -= hlen;
913 if (ip->ip_off & IP_MF) {
914 /*
915 * Make sure that fragments have a data length
916 * that's a non-zero multiple of 8 bytes.
917 */
918 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
919 IPSTAT_INC(ips_toosmall); /* XXX */
920 goto dropfrag;
921 }
922 m->m_flags |= M_FRAG;
923 } else
924 m->m_flags &= ~M_FRAG;
925 ip->ip_off <<= 3;
926
927
928 /*
929 * Attempt reassembly; if it succeeds, proceed.
930 * ip_reass() will return a different mbuf.
931 */
932 IPSTAT_INC(ips_fragments);
933 m->m_pkthdr.header = ip;
934
935 /* Previous ip_reass() started here. */
936 /*
937 * Presence of header sizes in mbufs
938 * would confuse code below.
939 */
940 m->m_data += hlen;
941 m->m_len -= hlen;
942
943 /*
944 * If first fragment to arrive, create a reassembly queue.
945 */
946 if (fp == NULL) {
947 fp = uma_zalloc(V_ipq_zone, M_NOWAIT);
948 if (fp == NULL)
949 goto dropfrag;
950 #ifdef MAC
951 if (mac_ipq_init(fp, M_NOWAIT) != 0) {
952 uma_zfree(V_ipq_zone, fp);
953 fp = NULL;
954 goto dropfrag;
955 }
956 mac_ipq_create(m, fp);
957 #endif
958 TAILQ_INSERT_HEAD(head, fp, ipq_list);
959 V_nipq++;
960 fp->ipq_nfrags = 1;
961 fp->ipq_ttl = IPFRAGTTL;
962 fp->ipq_p = ip->ip_p;
963 fp->ipq_id = ip->ip_id;
964 fp->ipq_src = ip->ip_src;
965 fp->ipq_dst = ip->ip_dst;
966 fp->ipq_frags = m;
967 m->m_nextpkt = NULL;
968 goto done;
969 } else {
970 fp->ipq_nfrags++;
971 #ifdef MAC
972 mac_ipq_update(m, fp);
973 #endif
974 }
975
976 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
977
978 /*
979 * Handle ECN by comparing this segment with the first one;
980 * if CE is set, do not lose CE.
981 * drop if CE and not-ECT are mixed for the same packet.
982 */
983 ecn = ip->ip_tos & IPTOS_ECN_MASK;
984 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
985 if (ecn == IPTOS_ECN_CE) {
986 if (ecn0 == IPTOS_ECN_NOTECT)
987 goto dropfrag;
988 if (ecn0 != IPTOS_ECN_CE)
989 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
990 }
991 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
992 goto dropfrag;
993
994 /*
995 * Find a segment which begins after this one does.
996 */
997 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
998 if (GETIP(q)->ip_off > ip->ip_off)
999 break;
1000
1001 /*
1002 * If there is a preceding segment, it may provide some of
1003 * our data already. If so, drop the data from the incoming
1004 * segment. If it provides all of our data, drop us, otherwise
1005 * stick new segment in the proper place.
1006 *
1007 * If some of the data is dropped from the preceding
1008 * segment, then it's checksum is invalidated.
1009 */
1010 if (p) {
1011 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
1012 if (i > 0) {
1013 if (i >= ip->ip_len)
1014 goto dropfrag;
1015 m_adj(m, i);
1016 m->m_pkthdr.csum_flags = 0;
1017 ip->ip_off += i;
1018 ip->ip_len -= i;
1019 }
1020 m->m_nextpkt = p->m_nextpkt;
1021 p->m_nextpkt = m;
1022 } else {
1023 m->m_nextpkt = fp->ipq_frags;
1024 fp->ipq_frags = m;
1025 }
1026
1027 /*
1028 * While we overlap succeeding segments trim them or,
1029 * if they are completely covered, dequeue them.
1030 */
1031 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
1032 q = nq) {
1033 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
1034 if (i < GETIP(q)->ip_len) {
1035 GETIP(q)->ip_len -= i;
1036 GETIP(q)->ip_off += i;
1037 m_adj(q, i);
1038 q->m_pkthdr.csum_flags = 0;
1039 break;
1040 }
1041 nq = q->m_nextpkt;
1042 m->m_nextpkt = nq;
1043 IPSTAT_INC(ips_fragdropped);
1044 fp->ipq_nfrags--;
1045 m_freem(q);
1046 }
1047
1048 /*
1049 * Check for complete reassembly and perform frag per packet
1050 * limiting.
1051 *
1052 * Frag limiting is performed here so that the nth frag has
1053 * a chance to complete the packet before we drop the packet.
1054 * As a result, n+1 frags are actually allowed per packet, but
1055 * only n will ever be stored. (n = maxfragsperpacket.)
1056 *
1057 */
1058 next = 0;
1059 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1060 if (GETIP(q)->ip_off != next) {
1061 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1062 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1063 ip_freef(head, fp);
1064 }
1065 goto done;
1066 }
1067 next += GETIP(q)->ip_len;
1068 }
1069 /* Make sure the last packet didn't have the IP_MF flag */
1070 if (p->m_flags & M_FRAG) {
1071 if (fp->ipq_nfrags > V_maxfragsperpacket) {
1072 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1073 ip_freef(head, fp);
1074 }
1075 goto done;
1076 }
1077
1078 /*
1079 * Reassembly is complete. Make sure the packet is a sane size.
1080 */
1081 q = fp->ipq_frags;
1082 ip = GETIP(q);
1083 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
1084 IPSTAT_INC(ips_toolong);
1085 IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags);
1086 ip_freef(head, fp);
1087 goto done;
1088 }
1089
1090 /*
1091 * Concatenate fragments.
1092 */
1093 m = q;
1094 t = m->m_next;
1095 m->m_next = NULL;
1096 m_cat(m, t);
1097 nq = q->m_nextpkt;
1098 q->m_nextpkt = NULL;
1099 for (q = nq; q != NULL; q = nq) {
1100 nq = q->m_nextpkt;
1101 q->m_nextpkt = NULL;
1102 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1103 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1104 m_cat(m, q);
1105 }
1106 /*
1107 * In order to do checksumming faster we do 'end-around carry' here
1108 * (and not in for{} loop), though it implies we are not going to
1109 * reassemble more than 64k fragments.
1110 */
1111 m->m_pkthdr.csum_data =
1112 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16);
1113 #ifdef MAC
1114 mac_ipq_reassemble(fp, m);
1115 mac_ipq_destroy(fp);
1116 #endif
1117
1118 /*
1119 * Create header for new ip packet by modifying header of first
1120 * packet; dequeue and discard fragment reassembly header.
1121 * Make header visible.
1122 */
1123 ip->ip_len = (ip->ip_hl << 2) + next;
1124 ip->ip_src = fp->ipq_src;
1125 ip->ip_dst = fp->ipq_dst;
1126 TAILQ_REMOVE(head, fp, ipq_list);
1127 V_nipq--;
1128 uma_zfree(V_ipq_zone, fp);
1129 m->m_len += (ip->ip_hl << 2);
1130 m->m_data -= (ip->ip_hl << 2);
1131 /* some debugging cruft by sklower, below, will go away soon */
1132 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
1133 m_fixhdr(m);
1134 IPSTAT_INC(ips_reassembled);
1135 IPQ_UNLOCK();
1136 return (m);
1137
1138 dropfrag:
1139 IPSTAT_INC(ips_fragdropped);
1140 if (fp != NULL)
1141 fp->ipq_nfrags--;
1142 m_freem(m);
1143 done:
1144 IPQ_UNLOCK();
1145 return (NULL);
1146
1147 #undef GETIP
1148 }
1149
1150 /*
1151 * Free a fragment reassembly header and all
1152 * associated datagrams.
1153 */
1154 static void
1155 ip_freef(struct ipqhead *fhp, struct ipq *fp)
1156 {
1157 struct mbuf *q;
1158
1159 IPQ_LOCK_ASSERT();
1160
1161 while (fp->ipq_frags) {
1162 q = fp->ipq_frags;
1163 fp->ipq_frags = q->m_nextpkt;
1164 m_freem(q);
1165 }
1166 TAILQ_REMOVE(fhp, fp, ipq_list);
1167 uma_zfree(V_ipq_zone, fp);
1168 V_nipq--;
1169 }
1170
1171 /*
1172 * IP timer processing;
1173 * if a timer expires on a reassembly
1174 * queue, discard it.
1175 */
1176 void
1177 ip_slowtimo(void)
1178 {
1179 VNET_ITERATOR_DECL(vnet_iter);
1180 struct ipq *fp;
1181 int i;
1182
1183 VNET_LIST_RLOCK_NOSLEEP();
1184 IPQ_LOCK();
1185 VNET_FOREACH(vnet_iter) {
1186 CURVNET_SET(vnet_iter);
1187 for (i = 0; i < IPREASS_NHASH; i++) {
1188 for(fp = TAILQ_FIRST(&V_ipq[i]); fp;) {
1189 struct ipq *fpp;
1190
1191 fpp = fp;
1192 fp = TAILQ_NEXT(fp, ipq_list);
1193 if(--fpp->ipq_ttl == 0) {
1194 IPSTAT_ADD(ips_fragtimeout,
1195 fpp->ipq_nfrags);
1196 ip_freef(&V_ipq[i], fpp);
1197 }
1198 }
1199 }
1200 /*
1201 * If we are over the maximum number of fragments
1202 * (due to the limit being lowered), drain off
1203 * enough to get down to the new limit.
1204 */
1205 if (V_maxnipq >= 0 && V_nipq > V_maxnipq) {
1206 for (i = 0; i < IPREASS_NHASH; i++) {
1207 while (V_nipq > V_maxnipq &&
1208 !TAILQ_EMPTY(&V_ipq[i])) {
1209 IPSTAT_ADD(ips_fragdropped,
1210 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1211 ip_freef(&V_ipq[i],
1212 TAILQ_FIRST(&V_ipq[i]));
1213 }
1214 }
1215 }
1216 CURVNET_RESTORE();
1217 }
1218 IPQ_UNLOCK();
1219 VNET_LIST_RUNLOCK_NOSLEEP();
1220 }
1221
1222 /*
1223 * Drain off all datagram fragments.
1224 */
1225 static void
1226 ip_drain_locked(void)
1227 {
1228 int i;
1229
1230 IPQ_LOCK_ASSERT();
1231
1232 for (i = 0; i < IPREASS_NHASH; i++) {
1233 while(!TAILQ_EMPTY(&V_ipq[i])) {
1234 IPSTAT_ADD(ips_fragdropped,
1235 TAILQ_FIRST(&V_ipq[i])->ipq_nfrags);
1236 ip_freef(&V_ipq[i], TAILQ_FIRST(&V_ipq[i]));
1237 }
1238 }
1239 }
1240
1241 void
1242 ip_drain(void)
1243 {
1244 VNET_ITERATOR_DECL(vnet_iter);
1245
1246 VNET_LIST_RLOCK_NOSLEEP();
1247 IPQ_LOCK();
1248 VNET_FOREACH(vnet_iter) {
1249 CURVNET_SET(vnet_iter);
1250 ip_drain_locked();
1251 CURVNET_RESTORE();
1252 }
1253 IPQ_UNLOCK();
1254 VNET_LIST_RUNLOCK_NOSLEEP();
1255 in_rtqdrain();
1256 }
1257
1258 /*
1259 * The protocol to be inserted into ip_protox[] must be already registered
1260 * in inetsw[], either statically or through pf_proto_register().
1261 */
1262 int
1263 ipproto_register(short ipproto)
1264 {
1265 struct protosw *pr;
1266
1267 /* Sanity checks. */
1268 if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
1269 return (EPROTONOSUPPORT);
1270
1271 /*
1272 * The protocol slot must not be occupied by another protocol
1273 * already. An index pointing to IPPROTO_RAW is unused.
1274 */
1275 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1276 if (pr == NULL)
1277 return (EPFNOSUPPORT);
1278 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
1279 return (EEXIST);
1280
1281 /* Find the protocol position in inetsw[] and set the index. */
1282 for (pr = inetdomain.dom_protosw;
1283 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
1284 if (pr->pr_domain->dom_family == PF_INET &&
1285 pr->pr_protocol && pr->pr_protocol == ipproto) {
1286 ip_protox[pr->pr_protocol] = pr - inetsw;
1287 return (0);
1288 }
1289 }
1290 return (EPROTONOSUPPORT);
1291 }
1292
1293 int
1294 ipproto_unregister(short ipproto)
1295 {
1296 struct protosw *pr;
1297
1298 /* Sanity checks. */
1299 if (ipproto <= 0 || ipproto >= IPPROTO_MAX)
1300 return (EPROTONOSUPPORT);
1301
1302 /* Check if the protocol was indeed registered. */
1303 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1304 if (pr == NULL)
1305 return (EPFNOSUPPORT);
1306 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
1307 return (ENOENT);
1308
1309 /* Reset the protocol slot to IPPROTO_RAW. */
1310 ip_protox[ipproto] = pr - inetsw;
1311 return (0);
1312 }
1313
1314 /*
1315 * Given address of next destination (final or next hop), return (referenced)
1316 * internet address info of interface to be used to get there.
1317 */
1318 struct in_ifaddr *
1319 ip_rtaddr(struct in_addr dst, u_int fibnum)
1320 {
1321 struct route sro;
1322 struct sockaddr_in *sin;
1323 struct in_ifaddr *ia;
1324
1325 bzero(&sro, sizeof(sro));
1326 sin = (struct sockaddr_in *)&sro.ro_dst;
1327 sin->sin_family = AF_INET;
1328 sin->sin_len = sizeof(*sin);
1329 sin->sin_addr = dst;
1330 in_rtalloc_ign(&sro, 0, fibnum);
1331
1332 if (sro.ro_rt == NULL)
1333 return (NULL);
1334
1335 ia = ifatoia(sro.ro_rt->rt_ifa);
1336 ifa_ref(&ia->ia_ifa);
1337 RTFREE(sro.ro_rt);
1338 return (ia);
1339 }
1340
1341 u_char inetctlerrmap[PRC_NCMDS] = {
1342 0, 0, 0, 0,
1343 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1344 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1345 EMSGSIZE, EHOSTUNREACH, 0, 0,
1346 0, 0, EHOSTUNREACH, 0,
1347 ENOPROTOOPT, ECONNREFUSED
1348 };
1349
1350 /*
1351 * Forward a packet. If some error occurs return the sender
1352 * an icmp packet. Note we can't always generate a meaningful
1353 * icmp message because icmp doesn't have a large enough repertoire
1354 * of codes and types.
1355 *
1356 * If not forwarding, just drop the packet. This could be confusing
1357 * if ipforwarding was zero but some routing protocol was advancing
1358 * us as a gateway to somewhere. However, we must let the routing
1359 * protocol deal with that.
1360 *
1361 * The srcrt parameter indicates whether the packet is being forwarded
1362 * via a source route.
1363 */
1364 void
1365 ip_forward(struct mbuf *m, int srcrt)
1366 {
1367 struct ip *ip = mtod(m, struct ip *);
1368 struct in_ifaddr *ia;
1369 struct mbuf *mcopy;
1370 struct in_addr dest;
1371 struct route ro;
1372 int error, type = 0, code = 0, mtu = 0;
1373
1374 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1375 IPSTAT_INC(ips_cantforward);
1376 m_freem(m);
1377 return;
1378 }
1379 #ifdef IPSTEALTH
1380 if (!V_ipstealth) {
1381 #endif
1382 if (ip->ip_ttl <= IPTTLDEC) {
1383 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
1384 0, 0);
1385 return;
1386 }
1387 #ifdef IPSTEALTH
1388 }
1389 #endif
1390
1391 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
1392 #ifndef IPSEC
1393 /*
1394 * 'ia' may be NULL if there is no route for this destination.
1395 * In case of IPsec, Don't discard it just yet, but pass it to
1396 * ip_output in case of outgoing IPsec policy.
1397 */
1398 if (!srcrt && ia == NULL) {
1399 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
1400 return;
1401 }
1402 #endif
1403
1404 /*
1405 * Save the IP header and at most 8 bytes of the payload,
1406 * in case we need to generate an ICMP message to the src.
1407 *
1408 * XXX this can be optimized a lot by saving the data in a local
1409 * buffer on the stack (72 bytes at most), and only allocating the
1410 * mbuf if really necessary. The vast majority of the packets
1411 * are forwarded without having to send an ICMP back (either
1412 * because unnecessary, or because rate limited), so we are
1413 * really we are wasting a lot of work here.
1414 *
1415 * We don't use m_copy() because it might return a reference
1416 * to a shared cluster. Both this function and ip_output()
1417 * assume exclusive access to the IP header in `m', so any
1418 * data in a cluster may change before we reach icmp_error().
1419 */
1420 MGETHDR(mcopy, M_DONTWAIT, m->m_type);
1421 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) {
1422 /*
1423 * It's probably ok if the pkthdr dup fails (because
1424 * the deep copy of the tag chain failed), but for now
1425 * be conservative and just discard the copy since
1426 * code below may some day want the tags.
1427 */
1428 m_free(mcopy);
1429 mcopy = NULL;
1430 }
1431 if (mcopy != NULL) {
1432 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy));
1433 mcopy->m_pkthdr.len = mcopy->m_len;
1434 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1435 }
1436
1437 #ifdef IPSTEALTH
1438 if (!V_ipstealth) {
1439 #endif
1440 ip->ip_ttl -= IPTTLDEC;
1441 #ifdef IPSTEALTH
1442 }
1443 #endif
1444
1445 /*
1446 * If forwarding packet using same interface that it came in on,
1447 * perhaps should send a redirect to sender to shortcut a hop.
1448 * Only send redirect if source is sending directly to us,
1449 * and if packet was not source routed (or has any options).
1450 * Also, don't send redirect if forwarding using a default route
1451 * or a route modified by a redirect.
1452 */
1453 dest.s_addr = 0;
1454 if (!srcrt && V_ipsendredirects &&
1455 ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
1456 struct sockaddr_in *sin;
1457 struct rtentry *rt;
1458
1459 bzero(&ro, sizeof(ro));
1460 sin = (struct sockaddr_in *)&ro.ro_dst;
1461 sin->sin_family = AF_INET;
1462 sin->sin_len = sizeof(*sin);
1463 sin->sin_addr = ip->ip_dst;
1464 in_rtalloc_ign(&ro, 0, M_GETFIB(m));
1465
1466 rt = ro.ro_rt;
1467
1468 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1469 satosin(rt_key(rt))->sin_addr.s_addr != 0) {
1470 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1471 u_long src = ntohl(ip->ip_src.s_addr);
1472
1473 if (RTA(rt) &&
1474 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1475 if (rt->rt_flags & RTF_GATEWAY)
1476 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
1477 else
1478 dest.s_addr = ip->ip_dst.s_addr;
1479 /* Router requirements says to only send host redirects */
1480 type = ICMP_REDIRECT;
1481 code = ICMP_REDIRECT_HOST;
1482 }
1483 }
1484 if (rt)
1485 RTFREE(rt);
1486 }
1487
1488 /*
1489 * Try to cache the route MTU from ip_output so we can consider it for
1490 * the ICMP_UNREACH_NEEDFRAG "Next-Hop MTU" field described in RFC1191.
1491 */
1492 bzero(&ro, sizeof(ro));
1493
1494 error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);
1495
1496 if (error == EMSGSIZE && ro.ro_rt)
1497 mtu = ro.ro_rt->rt_rmx.rmx_mtu;
1498 if (ro.ro_rt)
1499 RTFREE(ro.ro_rt);
1500
1501 if (error)
1502 IPSTAT_INC(ips_cantforward);
1503 else {
1504 IPSTAT_INC(ips_forward);
1505 if (type)
1506 IPSTAT_INC(ips_redirectsent);
1507 else {
1508 if (mcopy)
1509 m_freem(mcopy);
1510 if (ia != NULL)
1511 ifa_free(&ia->ia_ifa);
1512 return;
1513 }
1514 }
1515 if (mcopy == NULL) {
1516 if (ia != NULL)
1517 ifa_free(&ia->ia_ifa);
1518 return;
1519 }
1520
1521 switch (error) {
1522
1523 case 0: /* forwarded, but need redirect */
1524 /* type, code set above */
1525 break;
1526
1527 case ENETUNREACH:
1528 case EHOSTUNREACH:
1529 case ENETDOWN:
1530 case EHOSTDOWN:
1531 default:
1532 type = ICMP_UNREACH;
1533 code = ICMP_UNREACH_HOST;
1534 break;
1535
1536 case EMSGSIZE:
1537 type = ICMP_UNREACH;
1538 code = ICMP_UNREACH_NEEDFRAG;
1539
1540 #ifdef IPSEC
1541 /*
1542 * If IPsec is configured for this path,
1543 * override any possibly mtu value set by ip_output.
1544 */
1545 mtu = ip_ipsec_mtu(mcopy, mtu);
1546 #endif /* IPSEC */
1547 /*
1548 * If the MTU was set before make sure we are below the
1549 * interface MTU.
1550 * If the MTU wasn't set before use the interface mtu or
1551 * fall back to the next smaller mtu step compared to the
1552 * current packet size.
1553 */
1554 if (mtu != 0) {
1555 if (ia != NULL)
1556 mtu = min(mtu, ia->ia_ifp->if_mtu);
1557 } else {
1558 if (ia != NULL)
1559 mtu = ia->ia_ifp->if_mtu;
1560 else
1561 mtu = ip_next_mtu(ip->ip_len, 0);
1562 }
1563 IPSTAT_INC(ips_cantfrag);
1564 break;
1565
1566 case ENOBUFS:
1567 /*
1568 * A router should not generate ICMP_SOURCEQUENCH as
1569 * required in RFC1812 Requirements for IP Version 4 Routers.
1570 * Source quench could be a big problem under DoS attacks,
1571 * or if the underlying interface is rate-limited.
1572 * Those who need source quench packets may re-enable them
1573 * via the net.inet.ip.sendsourcequench sysctl.
1574 */
1575 if (V_ip_sendsourcequench == 0) {
1576 m_freem(mcopy);
1577 if (ia != NULL)
1578 ifa_free(&ia->ia_ifa);
1579 return;
1580 } else {
1581 type = ICMP_SOURCEQUENCH;
1582 code = 0;
1583 }
1584 break;
1585
1586 case EACCES: /* ipfw denied packet */
1587 m_freem(mcopy);
1588 if (ia != NULL)
1589 ifa_free(&ia->ia_ifa);
1590 return;
1591 }
1592 if (ia != NULL)
1593 ifa_free(&ia->ia_ifa);
1594 icmp_error(mcopy, type, code, dest.s_addr, mtu);
1595 }
1596
1597 void
1598 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1599 struct mbuf *m)
1600 {
1601
1602 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) {
1603 struct bintime bt;
1604
1605 bintime(&bt);
1606 if (inp->inp_socket->so_options & SO_BINTIME) {
1607 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt),
1608 SCM_BINTIME, SOL_SOCKET);
1609 if (*mp)
1610 mp = &(*mp)->m_next;
1611 }
1612 if (inp->inp_socket->so_options & SO_TIMESTAMP) {
1613 struct timeval tv;
1614
1615 bintime2timeval(&bt, &tv);
1616 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1617 SCM_TIMESTAMP, SOL_SOCKET);
1618 if (*mp)
1619 mp = &(*mp)->m_next;
1620 }
1621 }
1622 if (inp->inp_flags & INP_RECVDSTADDR) {
1623 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
1624 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1625 if (*mp)
1626 mp = &(*mp)->m_next;
1627 }
1628 if (inp->inp_flags & INP_RECVTTL) {
1629 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl,
1630 sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
1631 if (*mp)
1632 mp = &(*mp)->m_next;
1633 }
1634 #ifdef notyet
1635 /* XXX
1636 * Moving these out of udp_input() made them even more broken
1637 * than they already were.
1638 */
1639 /* options were tossed already */
1640 if (inp->inp_flags & INP_RECVOPTS) {
1641 *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
1642 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
1643 if (*mp)
1644 mp = &(*mp)->m_next;
1645 }
1646 /* ip_srcroute doesn't do what we want here, need to fix */
1647 if (inp->inp_flags & INP_RECVRETOPTS) {
1648 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m),
1649 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
1650 if (*mp)
1651 mp = &(*mp)->m_next;
1652 }
1653 #endif
1654 if (inp->inp_flags & INP_RECVIF) {
1655 struct ifnet *ifp;
1656 struct sdlbuf {
1657 struct sockaddr_dl sdl;
1658 u_char pad[32];
1659 } sdlbuf;
1660 struct sockaddr_dl *sdp;
1661 struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
1662
1663 if (((ifp = m->m_pkthdr.rcvif))
1664 && ( ifp->if_index && (ifp->if_index <= V_if_index))) {
1665 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
1666 /*
1667 * Change our mind and don't try copy.
1668 */
1669 if ((sdp->sdl_family != AF_LINK)
1670 || (sdp->sdl_len > sizeof(sdlbuf))) {
1671 goto makedummy;
1672 }
1673 bcopy(sdp, sdl2, sdp->sdl_len);
1674 } else {
1675 makedummy:
1676 sdl2->sdl_len
1677 = offsetof(struct sockaddr_dl, sdl_data[0]);
1678 sdl2->sdl_family = AF_LINK;
1679 sdl2->sdl_index = 0;
1680 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
1681 }
1682 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
1683 IP_RECVIF, IPPROTO_IP);
1684 if (*mp)
1685 mp = &(*mp)->m_next;
1686 }
1687 }
1688
1689 /*
1690 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
1691 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
1692 * locking. This code remains in ip_input.c as ip_mroute.c is optionally
1693 * compiled.
1694 */
1695 static VNET_DEFINE(int, ip_rsvp_on);
1696 VNET_DEFINE(struct socket *, ip_rsvpd);
1697
1698 #define V_ip_rsvp_on VNET(ip_rsvp_on)
1699
1700 int
1701 ip_rsvp_init(struct socket *so)
1702 {
1703
1704 if (so->so_type != SOCK_RAW ||
1705 so->so_proto->pr_protocol != IPPROTO_RSVP)
1706 return EOPNOTSUPP;
1707
1708 if (V_ip_rsvpd != NULL)
1709 return EADDRINUSE;
1710
1711 V_ip_rsvpd = so;
1712 /*
1713 * This may seem silly, but we need to be sure we don't over-increment
1714 * the RSVP counter, in case something slips up.
1715 */
1716 if (!V_ip_rsvp_on) {
1717 V_ip_rsvp_on = 1;
1718 V_rsvp_on++;
1719 }
1720
1721 return 0;
1722 }
1723
1724 int
1725 ip_rsvp_done(void)
1726 {
1727
1728 V_ip_rsvpd = NULL;
1729 /*
1730 * This may seem silly, but we need to be sure we don't over-decrement
1731 * the RSVP counter, in case something slips up.
1732 */
1733 if (V_ip_rsvp_on) {
1734 V_ip_rsvp_on = 0;
1735 V_rsvp_on--;
1736 }
1737 return 0;
1738 }
1739
1740 void
1741 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */
1742 {
1743
1744 if (rsvp_input_p) { /* call the real one if loaded */
1745 rsvp_input_p(m, off);
1746 return;
1747 }
1748
1749 /* Can still get packets with rsvp_on = 0 if there is a local member
1750 * of the group to which the RSVP packet is addressed. But in this
1751 * case we want to throw the packet away.
1752 */
1753
1754 if (!V_rsvp_on) {
1755 m_freem(m);
1756 return;
1757 }
1758
1759 if (V_ip_rsvpd != NULL) {
1760 rip_input(m, off);
1761 return;
1762 }
1763 /* Drop the packet */
1764 m_freem(m);
1765 }
Cache object: e37493134577a827f5a525df5b540118
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