2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
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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
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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
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23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
33 #include "opt_bootp.h"
35 #include "opt_ipstealth.h"
36 #include "opt_ipsec.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/callout.h>
45 #include <sys/malloc.h>
46 #include <sys/domain.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
50 #include <sys/kernel.h>
51 #include <sys/syslog.h>
52 #include <sys/sysctl.h>
56 #include <net/if_types.h>
57 #include <net/if_var.h>
58 #include <net/if_dl.h>
59 #include <net/route.h>
60 #include <net/netisr.h>
62 #include <netinet/in.h>
63 #include <netinet/in_systm.h>
64 #include <netinet/in_var.h>
65 #include <netinet/ip.h>
66 #include <netinet/in_pcb.h>
67 #include <netinet/ip_var.h>
68 #include <netinet/ip_icmp.h>
69 #include <netinet/ip_options.h>
70 #include <machine/in_cksum.h>
72 #include <netinet/ip_carp.h>
75 #include <sys/socketvar.h>
77 /* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */
78 #include <netinet/ip_fw.h>
79 #include <netinet/ip_dummynet.h>
82 #include <netinet6/ipsec.h>
83 #include <netkey/key.h>
87 #include <netipsec/ipsec.h>
88 #include <netipsec/key.h>
94 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
95 &ipforwarding, 0, "Enable IP forwarding between interfaces");
97 static int ipsendredirects = 1; /* XXX */
98 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
99 &ipsendredirects, 0, "Enable sending IP redirects");
101 int ip_defttl = IPDEFTTL;
102 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
103 &ip_defttl, 0, "Maximum TTL on IP packets");
105 static int ip_keepfaith = 0;
106 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
108 "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
110 static int ip_sendsourcequench = 0;
111 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
112 &ip_sendsourcequench, 0,
113 "Enable the transmission of source quench packets");
115 int ip_do_randomid = 0;
116 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
118 "Assign random ip_id values");
121 * XXX - Setting ip_checkinterface mostly implements the receive side of
122 * the Strong ES model described in RFC 1122, but since the routing table
123 * and transmit implementation do not implement the Strong ES model,
124 * setting this to 1 results in an odd hybrid.
126 * XXX - ip_checkinterface currently must be disabled if you use ipnat
127 * to translate the destination address to another local interface.
129 * XXX - ip_checkinterface must be disabled if you add IP aliases
130 * to the loopback interface instead of the interface where the
131 * packets for those addresses are received.
133 static int ip_checkinterface = 0;
134 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
135 &ip_checkinterface, 0, "Verify packet arrives on correct interface");
137 struct pfil_head inet_pfil_hook; /* Packet filter hooks */
139 static struct ifqueue ipintrq;
140 static int ipqmaxlen = IFQ_MAXLEN;
142 extern struct domain inetdomain;
143 extern struct protosw inetsw[];
144 u_char ip_protox[IPPROTO_MAX];
145 struct in_ifaddrhead in_ifaddrhead; /* first inet address */
146 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */
147 u_long in_ifaddrhmask; /* mask for hash table */
149 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW,
150 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue");
151 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD,
152 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue");
154 struct ipstat ipstat;
155 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
156 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)");
159 * IP datagram reassembly.
161 #define IPREASS_NHASH_LOG2 6
162 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
163 #define IPREASS_HMASK (IPREASS_NHASH - 1)
164 #define IPREASS_HASH(x,y) \
165 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
167 static uma_zone_t ipq_zone;
168 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH];
169 static struct mtx ipqlock;
171 #define IPQ_LOCK() mtx_lock(&ipqlock)
172 #define IPQ_UNLOCK() mtx_unlock(&ipqlock)
173 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
174 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
176 static void maxnipq_update(void);
178 static int maxnipq; /* Administrative limit on # reass queues. */
179 static int nipq = 0; /* Total # of reass queues */
180 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0,
181 "Current number of IPv4 fragment reassembly queue entries");
183 static int maxfragsperpacket;
184 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
185 &maxfragsperpacket, 0,
186 "Maximum number of IPv4 fragments allowed per packet");
188 struct callout ipport_tick_callout;
191 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
192 &ip_mtu, 0, "Default MTU");
197 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
202 * ipfw_ether and ipfw_bridge hooks.
203 * XXX: Temporary until those are converted to pfil_hooks as well.
205 ip_fw_chk_t *ip_fw_chk_ptr = NULL;
206 ip_dn_io_t *ip_dn_io_ptr = NULL;
210 static void ip_freef(struct ipqhead *, struct ipq *);
213 * IP initialization: fill in IP protocol switch table.
214 * All protocols not implemented in kernel go to raw IP protocol handler.
219 register struct protosw *pr;
222 TAILQ_INIT(&in_ifaddrhead);
223 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask);
224 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
226 panic("ip_init: PF_INET not found");
228 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
229 for (i = 0; i < IPPROTO_MAX; i++)
230 ip_protox[i] = pr - inetsw;
232 * Cycle through IP protocols and put them into the appropriate place
235 for (pr = inetdomain.dom_protosw;
236 pr < inetdomain.dom_protoswNPROTOSW; pr++)
237 if (pr->pr_domain->dom_family == PF_INET &&
238 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
239 /* Be careful to only index valid IP protocols. */
240 if (pr->pr_protocol < IPPROTO_MAX)
241 ip_protox[pr->pr_protocol] = pr - inetsw;
244 /* Initialize packet filter hooks. */
245 inet_pfil_hook.ph_type = PFIL_TYPE_AF;
246 inet_pfil_hook.ph_af = AF_INET;
247 if ((i = pfil_head_register(&inet_pfil_hook)) != 0)
248 printf("%s: WARNING: unable to register pfil hook, "
249 "error %d\n", __func__, i);
251 /* Initialize IP reassembly queue. */
253 for (i = 0; i < IPREASS_NHASH; i++)
255 maxnipq = nmbclusters / 32;
256 maxfragsperpacket = 16;
257 ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
258 NULL, UMA_ALIGN_PTR, 0);
261 /* Start ipport_tick. */
262 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE);
264 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL,
265 SHUTDOWN_PRI_DEFAULT);
267 /* Initialize various other remaining things. */
268 ip_id = time_second & 0xffff;
269 ipintrq.ifq_maxlen = ipqmaxlen;
270 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF);
271 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE);
277 callout_stop(&ipport_tick_callout);
281 * Ip input routine. Checksum and byte swap header. If fragmented
282 * try to reassemble. Process options. Pass to next level.
285 ip_input(struct mbuf *m)
287 struct ip *ip = NULL;
288 struct in_ifaddr *ia = NULL;
290 int checkif, hlen = 0;
292 int dchg = 0; /* dest changed after fw */
293 struct in_addr odst; /* original dst address */
296 struct tdb_ident *tdbi;
297 struct secpolicy *sp;
299 #endif /* FAST_IPSEC */
303 if (m->m_flags & M_FASTFWD_OURS) {
305 * Firewall or NAT changed destination to local.
306 * We expect ip_len and ip_off to be in host byte order.
308 m->m_flags &= ~M_FASTFWD_OURS;
309 /* Set up some basics that will be used later. */
310 ip = mtod(m, struct ip *);
311 hlen = ip->ip_hl << 2;
317 if (m->m_pkthdr.len < sizeof(struct ip))
320 if (m->m_len < sizeof (struct ip) &&
321 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
322 ipstat.ips_toosmall++;
325 ip = mtod(m, struct ip *);
327 if (ip->ip_v != IPVERSION) {
328 ipstat.ips_badvers++;
332 hlen = ip->ip_hl << 2;
333 if (hlen < sizeof(struct ip)) { /* minimum header length */
334 ipstat.ips_badhlen++;
337 if (hlen > m->m_len) {
338 if ((m = m_pullup(m, hlen)) == NULL) {
339 ipstat.ips_badhlen++;
342 ip = mtod(m, struct ip *);
345 /* 127/8 must not appear on wire - RFC1122 */
346 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
347 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
348 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
349 ipstat.ips_badaddr++;
354 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
355 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
357 if (hlen == sizeof(struct ip)) {
358 sum = in_cksum_hdr(ip);
360 sum = in_cksum(m, hlen);
369 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
370 /* packet is dropped by traffic conditioner */
375 * Convert fields to host representation.
377 ip->ip_len = ntohs(ip->ip_len);
378 if (ip->ip_len < hlen) {
382 ip->ip_off = ntohs(ip->ip_off);
385 * Check that the amount of data in the buffers
386 * is as at least much as the IP header would have us expect.
387 * Trim mbufs if longer than we expect.
388 * Drop packet if shorter than we expect.
390 if (m->m_pkthdr.len < ip->ip_len) {
392 ipstat.ips_tooshort++;
395 if (m->m_pkthdr.len > ip->ip_len) {
396 if (m->m_len == m->m_pkthdr.len) {
397 m->m_len = ip->ip_len;
398 m->m_pkthdr.len = ip->ip_len;
400 m_adj(m, ip->ip_len - m->m_pkthdr.len);
402 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF)
404 * Bypass packet filtering for packets from a tunnel (gif).
406 if (ipsec_getnhist(m))
409 #if defined(FAST_IPSEC) && !defined(IPSEC_FILTERGIF)
411 * Bypass packet filtering for packets from a tunnel (gif).
413 if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
418 * Run through list of hooks for input packets.
420 * NB: Beware of the destination address changing (e.g.
421 * by NAT rewriting). When this happens, tell
422 * ip_forward to do the right thing.
425 /* Jump over all PFIL processing if hooks are not active. */
426 if (inet_pfil_hook.ph_busy_count == -1)
430 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif,
433 if (m == NULL) /* consumed by filter */
436 ip = mtod(m, struct ip *);
437 dchg = (odst.s_addr != ip->ip_dst.s_addr);
439 #ifdef IPFIREWALL_FORWARD
440 if (m->m_flags & M_FASTFWD_OURS) {
441 m->m_flags &= ~M_FASTFWD_OURS;
444 #ifndef IPFIREWALL_FORWARD_EXTENDED
445 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL);
447 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) {
449 * Directly ship on the packet. This allows to forward packets
450 * that were destined for us to some other directly connected
456 #endif /* IPFIREWALL_FORWARD_EXTENDED */
457 #endif /* IPFIREWALL_FORWARD */
461 * Process options and, if not destined for us,
462 * ship it on. ip_dooptions returns 1 when an
463 * error was detected (causing an icmp message
464 * to be sent and the original packet to be freed).
466 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
469 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
470 * matter if it is destined to another node, or whether it is
471 * a multicast one, RSVP wants it! and prevents it from being forwarded
472 * anywhere else. Also checks if the rsvp daemon is running before
473 * grabbing the packet.
475 if (rsvp_on && ip->ip_p==IPPROTO_RSVP)
479 * Check our list of addresses, to see if the packet is for us.
480 * If we don't have any addresses, assume any unicast packet
481 * we receive might be for us (and let the upper layers deal
484 if (TAILQ_EMPTY(&in_ifaddrhead) &&
485 (m->m_flags & (M_MCAST|M_BCAST)) == 0)
489 * Enable a consistency check between the destination address
490 * and the arrival interface for a unicast packet (the RFC 1122
491 * strong ES model) if IP forwarding is disabled and the packet
492 * is not locally generated and the packet is not subject to
495 * XXX - Checking also should be disabled if the destination
496 * address is ipnat'ed to a different interface.
498 * XXX - Checking is incompatible with IP aliases added
499 * to the loopback interface instead of the interface where
500 * the packets are received.
502 * XXX - This is the case for carp vhost IPs as well so we
503 * insert a workaround. If the packet got here, we already
504 * checked with carp_iamatch() and carp_forus().
506 checkif = ip_checkinterface && (ipforwarding == 0) &&
507 m->m_pkthdr.rcvif != NULL &&
508 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) &&
510 !m->m_pkthdr.rcvif->if_carp &&
515 * Check for exact addresses in the hash bucket.
517 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
519 * If the address matches, verify that the packet
520 * arrived via the correct interface if checking is
523 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
524 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif))
528 * Check for broadcast addresses.
530 * Only accept broadcast packets that arrive via the matching
531 * interface. Reception of forwarded directed broadcasts would
532 * be handled via ip_forward() and ether_output() with the loopback
533 * into the stack for SIMPLEX interfaces handled by ether_output().
535 if (m->m_pkthdr.rcvif != NULL &&
536 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
537 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
538 if (ifa->ifa_addr->sa_family != AF_INET)
541 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
544 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr)
547 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
552 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
553 struct in_multi *inm;
556 * If we are acting as a multicast router, all
557 * incoming multicast packets are passed to the
558 * kernel-level multicast forwarding function.
559 * The packet is returned (relatively) intact; if
560 * ip_mforward() returns a non-zero value, the packet
561 * must be discarded, else it may be accepted below.
564 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) {
565 ipstat.ips_cantforward++;
571 * The process-level routing daemon needs to receive
572 * all multicast IGMP packets, whether or not this
573 * host belongs to their destination groups.
575 if (ip->ip_p == IPPROTO_IGMP)
577 ipstat.ips_forward++;
580 * See if we belong to the destination multicast group on the
584 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
587 ipstat.ips_notmember++;
593 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
595 if (ip->ip_dst.s_addr == INADDR_ANY)
599 * FAITH(Firewall Aided Internet Translator)
601 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
603 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
611 * Not for us; forward if possible and desirable.
613 if (ipforwarding == 0) {
614 ipstat.ips_cantforward++;
619 * Enforce inbound IPsec SPD.
621 if (ipsec4_in_reject(m, NULL)) {
622 ipsecstat.in_polvio++;
627 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
630 tdbi = (struct tdb_ident *)(mtag + 1);
631 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
633 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
634 IP_FORWARDING, &error);
636 if (sp == NULL) { /* NB: can happen if error */
638 /*XXX error stat???*/
639 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
644 * Check security policy against packet attributes.
646 error = ipsec_in_reject(sp, m);
650 ipstat.ips_cantforward++;
653 #endif /* FAST_IPSEC */
661 * IPSTEALTH: Process non-routing options only
662 * if the packet is destined for us.
664 if (ipstealth && hlen > sizeof (struct ip) &&
667 #endif /* IPSTEALTH */
669 /* Count the packet in the ip address stats */
671 ia->ia_ifa.if_ipackets++;
672 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
676 * Attempt reassembly; if it succeeds, proceed.
677 * ip_reass() will return a different mbuf.
679 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
683 ip = mtod(m, struct ip *);
684 /* Get the header length of the reassembled packet */
685 hlen = ip->ip_hl << 2;
689 * Further protocols expect the packet length to be w/o the
696 * enforce IPsec policy checking if we are seeing last header.
697 * note that we do not visit this with protocols with pcb layer
698 * code - like udp/tcp/raw ip.
700 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 &&
701 ipsec4_in_reject(m, NULL)) {
702 ipsecstat.in_polvio++;
708 * enforce IPsec policy checking if we are seeing last header.
709 * note that we do not visit this with protocols with pcb layer
710 * code - like udp/tcp/raw ip.
712 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
714 * Check if the packet has already had IPsec processing
715 * done. If so, then just pass it along. This tag gets
716 * set during AH, ESP, etc. input handling, before the
717 * packet is returned to the ip input queue for delivery.
719 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
722 tdbi = (struct tdb_ident *)(mtag + 1);
723 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
725 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
726 IP_FORWARDING, &error);
730 * Check security policy against packet attributes.
732 error = ipsec_in_reject(sp, m);
735 /* XXX error stat??? */
737 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
744 #endif /* FAST_IPSEC */
747 * Switch out to protocol's input routine.
749 ipstat.ips_delivered++;
751 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
758 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
759 * max has slightly different semantics than the sysctl, for historical
767 * -1 for unlimited allocation.
770 uma_zone_set_max(ipq_zone, 0);
772 * Positive number for specific bound.
775 uma_zone_set_max(ipq_zone, maxnipq);
777 * Zero specifies no further fragment queue allocation -- set the
778 * bound very low, but rely on implementation elsewhere to actually
779 * prevent allocation and reclaim current queues.
782 uma_zone_set_max(ipq_zone, 1);
786 sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
791 error = sysctl_handle_int(oidp, &i, 0, req);
792 if (error || !req->newptr)
796 * XXXRW: Might be a good idea to sanity check the argument and place
797 * an extreme upper bound.
806 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
807 NULL, 0, sysctl_maxnipq, "I",
808 "Maximum number of IPv4 fragment reassembly queue entries");
811 * Take incoming datagram fragment and try to reassemble it into
812 * whole datagram. If the argument is the first fragment or one
813 * in between the function will return NULL and store the mbuf
814 * in the fragment chain. If the argument is the last fragment
815 * the packet will be reassembled and the pointer to the new
816 * mbuf returned for further processing. Only m_tags attached
817 * to the first packet/fragment are preserved.
818 * The IP header is *NOT* adjusted out of iplen.
822 ip_reass(struct mbuf *m)
825 struct mbuf *p, *q, *nq, *t;
826 struct ipq *fp = NULL;
827 struct ipqhead *head;
832 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
833 if (maxnipq == 0 || maxfragsperpacket == 0) {
834 ipstat.ips_fragments++;
835 ipstat.ips_fragdropped++;
840 ip = mtod(m, struct ip *);
841 hlen = ip->ip_hl << 2;
843 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
848 * Look for queue of fragments
851 TAILQ_FOREACH(fp, head, ipq_list)
852 if (ip->ip_id == fp->ipq_id &&
853 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
854 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
856 mac_fragment_match(m, fp) &&
858 ip->ip_p == fp->ipq_p)
864 * Attempt to trim the number of allocated fragment queues if it
865 * exceeds the administrative limit.
867 if ((nipq > maxnipq) && (maxnipq > 0)) {
869 * drop something from the tail of the current queue
870 * before proceeding further
872 struct ipq *q = TAILQ_LAST(head, ipqhead);
873 if (q == NULL) { /* gak */
874 for (i = 0; i < IPREASS_NHASH; i++) {
875 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
877 ipstat.ips_fragtimeout += r->ipq_nfrags;
878 ip_freef(&ipq[i], r);
883 ipstat.ips_fragtimeout += q->ipq_nfrags;
890 * Adjust ip_len to not reflect header,
891 * convert offset of this to bytes.
894 if (ip->ip_off & IP_MF) {
896 * Make sure that fragments have a data length
897 * that's a non-zero multiple of 8 bytes.
899 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
900 ipstat.ips_toosmall++; /* XXX */
903 m->m_flags |= M_FRAG;
905 m->m_flags &= ~M_FRAG;
910 * Attempt reassembly; if it succeeds, proceed.
911 * ip_reass() will return a different mbuf.
913 ipstat.ips_fragments++;
914 m->m_pkthdr.header = ip;
916 /* Previous ip_reass() started here. */
918 * Presence of header sizes in mbufs
919 * would confuse code below.
925 * If first fragment to arrive, create a reassembly queue.
928 fp = uma_zalloc(ipq_zone, M_NOWAIT);
932 if (mac_init_ipq(fp, M_NOWAIT) != 0) {
933 uma_zfree(ipq_zone, fp);
936 mac_create_ipq(m, fp);
938 TAILQ_INSERT_HEAD(head, fp, ipq_list);
941 fp->ipq_ttl = IPFRAGTTL;
942 fp->ipq_p = ip->ip_p;
943 fp->ipq_id = ip->ip_id;
944 fp->ipq_src = ip->ip_src;
945 fp->ipq_dst = ip->ip_dst;
952 mac_update_ipq(m, fp);
956 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
959 * Handle ECN by comparing this segment with the first one;
960 * if CE is set, do not lose CE.
961 * drop if CE and not-ECT are mixed for the same packet.
963 ecn = ip->ip_tos & IPTOS_ECN_MASK;
964 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
965 if (ecn == IPTOS_ECN_CE) {
966 if (ecn0 == IPTOS_ECN_NOTECT)
968 if (ecn0 != IPTOS_ECN_CE)
969 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
971 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
975 * Find a segment which begins after this one does.
977 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
978 if (GETIP(q)->ip_off > ip->ip_off)
982 * If there is a preceding segment, it may provide some of
983 * our data already. If so, drop the data from the incoming
984 * segment. If it provides all of our data, drop us, otherwise
985 * stick new segment in the proper place.
987 * If some of the data is dropped from the the preceding
988 * segment, then it's checksum is invalidated.
991 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
996 m->m_pkthdr.csum_flags = 0;
1000 m->m_nextpkt = p->m_nextpkt;
1003 m->m_nextpkt = fp->ipq_frags;
1008 * While we overlap succeeding segments trim them or,
1009 * if they are completely covered, dequeue them.
1011 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
1013 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
1014 if (i < GETIP(q)->ip_len) {
1015 GETIP(q)->ip_len -= i;
1016 GETIP(q)->ip_off += i;
1018 q->m_pkthdr.csum_flags = 0;
1023 ipstat.ips_fragdropped++;
1029 * Check for complete reassembly and perform frag per packet
1032 * Frag limiting is performed here so that the nth frag has
1033 * a chance to complete the packet before we drop the packet.
1034 * As a result, n+1 frags are actually allowed per packet, but
1035 * only n will ever be stored. (n = maxfragsperpacket.)
1039 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1040 if (GETIP(q)->ip_off != next) {
1041 if (fp->ipq_nfrags > maxfragsperpacket) {
1042 ipstat.ips_fragdropped += fp->ipq_nfrags;
1047 next += GETIP(q)->ip_len;
1049 /* Make sure the last packet didn't have the IP_MF flag */
1050 if (p->m_flags & M_FRAG) {
1051 if (fp->ipq_nfrags > maxfragsperpacket) {
1052 ipstat.ips_fragdropped += fp->ipq_nfrags;
1059 * Reassembly is complete. Make sure the packet is a sane size.
1063 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
1064 ipstat.ips_toolong++;
1065 ipstat.ips_fragdropped += fp->ipq_nfrags;
1071 * Concatenate fragments.
1078 q->m_nextpkt = NULL;
1079 for (q = nq; q != NULL; q = nq) {
1081 q->m_nextpkt = NULL;
1082 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1083 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1087 mac_create_datagram_from_ipq(fp, m);
1088 mac_destroy_ipq(fp);
1092 * Create header for new ip packet by modifying header of first
1093 * packet; dequeue and discard fragment reassembly header.
1094 * Make header visible.
1096 ip->ip_len = (ip->ip_hl << 2) + next;
1097 ip->ip_src = fp->ipq_src;
1098 ip->ip_dst = fp->ipq_dst;
1099 TAILQ_REMOVE(head, fp, ipq_list);
1101 uma_zfree(ipq_zone, fp);
1102 m->m_len += (ip->ip_hl << 2);
1103 m->m_data -= (ip->ip_hl << 2);
1104 /* some debugging cruft by sklower, below, will go away soon */
1105 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
1107 ipstat.ips_reassembled++;
1112 ipstat.ips_fragdropped++;
1124 * Free a fragment reassembly header and all
1125 * associated datagrams.
1129 struct ipqhead *fhp;
1132 register struct mbuf *q;
1136 while (fp->ipq_frags) {
1138 fp->ipq_frags = q->m_nextpkt;
1141 TAILQ_REMOVE(fhp, fp, ipq_list);
1142 uma_zfree(ipq_zone, fp);
1147 * IP timer processing;
1148 * if a timer expires on a reassembly
1149 * queue, discard it.
1154 register struct ipq *fp;
1158 for (i = 0; i < IPREASS_NHASH; i++) {
1159 for(fp = TAILQ_FIRST(&ipq[i]); fp;) {
1163 fp = TAILQ_NEXT(fp, ipq_list);
1164 if(--fpp->ipq_ttl == 0) {
1165 ipstat.ips_fragtimeout += fpp->ipq_nfrags;
1166 ip_freef(&ipq[i], fpp);
1171 * If we are over the maximum number of fragments
1172 * (due to the limit being lowered), drain off
1173 * enough to get down to the new limit.
1175 if (maxnipq >= 0 && nipq > maxnipq) {
1176 for (i = 0; i < IPREASS_NHASH; i++) {
1177 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) {
1178 ipstat.ips_fragdropped +=
1179 TAILQ_FIRST(&ipq[i])->ipq_nfrags;
1180 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
1188 * Drain off all datagram fragments.
1196 for (i = 0; i < IPREASS_NHASH; i++) {
1197 while(!TAILQ_EMPTY(&ipq[i])) {
1198 ipstat.ips_fragdropped +=
1199 TAILQ_FIRST(&ipq[i])->ipq_nfrags;
1200 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
1208 * The protocol to be inserted into ip_protox[] must be already registered
1209 * in inetsw[], either statically or through pf_proto_register().
1212 ipproto_register(u_char ipproto)
1216 /* Sanity checks. */
1218 return (EPROTONOSUPPORT);
1221 * The protocol slot must not be occupied by another protocol
1222 * already. An index pointing to IPPROTO_RAW is unused.
1224 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1226 return (EPFNOSUPPORT);
1227 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
1230 /* Find the protocol position in inetsw[] and set the index. */
1231 for (pr = inetdomain.dom_protosw;
1232 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
1233 if (pr->pr_domain->dom_family == PF_INET &&
1234 pr->pr_protocol && pr->pr_protocol == ipproto) {
1235 /* Be careful to only index valid IP protocols. */
1236 if (pr->pr_protocol < IPPROTO_MAX) {
1237 ip_protox[pr->pr_protocol] = pr - inetsw;
1243 return (EPROTONOSUPPORT);
1247 ipproto_unregister(u_char ipproto)
1251 /* Sanity checks. */
1253 return (EPROTONOSUPPORT);
1255 /* Check if the protocol was indeed registered. */
1256 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1258 return (EPFNOSUPPORT);
1259 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
1262 /* Reset the protocol slot to IPPROTO_RAW. */
1263 ip_protox[ipproto] = pr - inetsw;
1268 * Given address of next destination (final or next hop),
1269 * return internet address info of interface to be used to get there.
1276 struct sockaddr_in *sin;
1277 struct in_ifaddr *ifa;
1279 bzero(&sro, sizeof(sro));
1280 sin = (struct sockaddr_in *)&sro.ro_dst;
1281 sin->sin_family = AF_INET;
1282 sin->sin_len = sizeof(*sin);
1283 sin->sin_addr = dst;
1284 rtalloc_ign(&sro, RTF_CLONING);
1286 if (sro.ro_rt == NULL)
1289 ifa = ifatoia(sro.ro_rt->rt_ifa);
1294 u_char inetctlerrmap[PRC_NCMDS] = {
1296 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1297 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1298 EMSGSIZE, EHOSTUNREACH, 0, 0,
1299 0, 0, EHOSTUNREACH, 0,
1300 ENOPROTOOPT, ECONNREFUSED
1304 * Forward a packet. If some error occurs return the sender
1305 * an icmp packet. Note we can't always generate a meaningful
1306 * icmp message because icmp doesn't have a large enough repertoire
1307 * of codes and types.
1309 * If not forwarding, just drop the packet. This could be confusing
1310 * if ipforwarding was zero but some routing protocol was advancing
1311 * us as a gateway to somewhere. However, we must let the routing
1312 * protocol deal with that.
1314 * The srcrt parameter indicates whether the packet is being forwarded
1315 * via a source route.
1318 ip_forward(struct mbuf *m, int srcrt)
1320 struct ip *ip = mtod(m, struct ip *);
1321 struct in_ifaddr *ia = NULL;
1323 struct in_addr dest;
1324 int error, type = 0, code = 0, mtu = 0;
1326 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1327 ipstat.ips_cantforward++;
1334 if (ip->ip_ttl <= IPTTLDEC) {
1335 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
1343 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) {
1344 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
1349 * Save the IP header and at most 8 bytes of the payload,
1350 * in case we need to generate an ICMP message to the src.
1352 * XXX this can be optimized a lot by saving the data in a local
1353 * buffer on the stack (72 bytes at most), and only allocating the
1354 * mbuf if really necessary. The vast majority of the packets
1355 * are forwarded without having to send an ICMP back (either
1356 * because unnecessary, or because rate limited), so we are
1357 * really we are wasting a lot of work here.
1359 * We don't use m_copy() because it might return a reference
1360 * to a shared cluster. Both this function and ip_output()
1361 * assume exclusive access to the IP header in `m', so any
1362 * data in a cluster may change before we reach icmp_error().
1364 MGETHDR(mcopy, M_DONTWAIT, m->m_type);
1365 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) {
1367 * It's probably ok if the pkthdr dup fails (because
1368 * the deep copy of the tag chain failed), but for now
1369 * be conservative and just discard the copy since
1370 * code below may some day want the tags.
1375 if (mcopy != NULL) {
1376 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy));
1377 mcopy->m_pkthdr.len = mcopy->m_len;
1378 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1384 ip->ip_ttl -= IPTTLDEC;
1390 * If forwarding packet using same interface that it came in on,
1391 * perhaps should send a redirect to sender to shortcut a hop.
1392 * Only send redirect if source is sending directly to us,
1393 * and if packet was not source routed (or has any options).
1394 * Also, don't send redirect if forwarding using a default route
1395 * or a route modified by a redirect.
1398 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) {
1399 struct sockaddr_in *sin;
1403 bzero(&ro, sizeof(ro));
1404 sin = (struct sockaddr_in *)&ro.ro_dst;
1405 sin->sin_family = AF_INET;
1406 sin->sin_len = sizeof(*sin);
1407 sin->sin_addr = ip->ip_dst;
1408 rtalloc_ign(&ro, RTF_CLONING);
1412 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1413 satosin(rt_key(rt))->sin_addr.s_addr != 0) {
1414 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1415 u_long src = ntohl(ip->ip_src.s_addr);
1418 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1419 if (rt->rt_flags & RTF_GATEWAY)
1420 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
1422 dest.s_addr = ip->ip_dst.s_addr;
1423 /* Router requirements says to only send host redirects */
1424 type = ICMP_REDIRECT;
1425 code = ICMP_REDIRECT_HOST;
1432 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
1434 ipstat.ips_cantforward++;
1436 ipstat.ips_forward++;
1438 ipstat.ips_redirectsent++;
1450 case 0: /* forwarded, but need redirect */
1451 /* type, code set above */
1454 case ENETUNREACH: /* shouldn't happen, checked above */
1459 type = ICMP_UNREACH;
1460 code = ICMP_UNREACH_HOST;
1464 type = ICMP_UNREACH;
1465 code = ICMP_UNREACH_NEEDFRAG;
1466 #if defined(IPSEC) || defined(FAST_IPSEC)
1468 * If the packet is routed over IPsec tunnel, tell the
1469 * originator the tunnel MTU.
1470 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
1474 struct secpolicy *sp = NULL;
1480 sp = ipsec4_getpolicybyaddr(mcopy,
1484 #else /* FAST_IPSEC */
1485 sp = ipsec_getpolicybyaddr(mcopy,
1491 /* count IPsec header size */
1492 ipsechdr = ipsec4_hdrsiz(mcopy,
1497 * find the correct route for outer IPv4
1498 * header, compute tunnel MTU.
1501 && sp->req->sav != NULL
1502 && sp->req->sav->sah != NULL) {
1503 ro = &sp->req->sav->sah->sa_route;
1504 if (ro->ro_rt && ro->ro_rt->rt_ifp) {
1506 ro->ro_rt->rt_rmx.rmx_mtu ?
1507 ro->ro_rt->rt_rmx.rmx_mtu :
1508 ro->ro_rt->rt_ifp->if_mtu;
1515 #else /* FAST_IPSEC */
1518 ipstat.ips_cantfrag++;
1521 #endif /*IPSEC || FAST_IPSEC*/
1523 * When doing source routing 'ia' can be NULL. Fall back
1524 * to the minimum guaranteed routeable packet size and use
1525 * the same hack as IPSEC to setup a dummyifp for icmp.
1530 mtu = ia->ia_ifp->if_mtu;
1531 #if defined(IPSEC) || defined(FAST_IPSEC)
1533 #endif /*IPSEC || FAST_IPSEC*/
1534 ipstat.ips_cantfrag++;
1539 * A router should not generate ICMP_SOURCEQUENCH as
1540 * required in RFC1812 Requirements for IP Version 4 Routers.
1541 * Source quench could be a big problem under DoS attacks,
1542 * or if the underlying interface is rate-limited.
1543 * Those who need source quench packets may re-enable them
1544 * via the net.inet.ip.sendsourcequench sysctl.
1546 if (ip_sendsourcequench == 0) {
1550 type = ICMP_SOURCEQUENCH;
1555 case EACCES: /* ipfw denied packet */
1559 icmp_error(mcopy, type, code, dest.s_addr, mtu);
1563 ip_savecontrol(inp, mp, ip, m)
1564 register struct inpcb *inp;
1565 register struct mbuf **mp;
1566 register struct ip *ip;
1567 register struct mbuf *m;
1569 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) {
1573 if (inp->inp_socket->so_options & SO_BINTIME) {
1574 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt),
1575 SCM_BINTIME, SOL_SOCKET);
1577 mp = &(*mp)->m_next;
1579 if (inp->inp_socket->so_options & SO_TIMESTAMP) {
1582 bintime2timeval(&bt, &tv);
1583 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1584 SCM_TIMESTAMP, SOL_SOCKET);
1586 mp = &(*mp)->m_next;
1589 if (inp->inp_flags & INP_RECVDSTADDR) {
1590 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
1591 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1593 mp = &(*mp)->m_next;
1595 if (inp->inp_flags & INP_RECVTTL) {
1596 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl,
1597 sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
1599 mp = &(*mp)->m_next;
1603 * Moving these out of udp_input() made them even more broken
1604 * than they already were.
1606 /* options were tossed already */
1607 if (inp->inp_flags & INP_RECVOPTS) {
1608 *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
1609 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
1611 mp = &(*mp)->m_next;
1613 /* ip_srcroute doesn't do what we want here, need to fix */
1614 if (inp->inp_flags & INP_RECVRETOPTS) {
1615 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m),
1616 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
1618 mp = &(*mp)->m_next;
1621 if (inp->inp_flags & INP_RECVIF) {
1624 struct sockaddr_dl sdl;
1627 struct sockaddr_dl *sdp;
1628 struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
1630 if (((ifp = m->m_pkthdr.rcvif))
1631 && ( ifp->if_index && (ifp->if_index <= if_index))) {
1632 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
1634 * Change our mind and don't try copy.
1636 if ((sdp->sdl_family != AF_LINK)
1637 || (sdp->sdl_len > sizeof(sdlbuf))) {
1640 bcopy(sdp, sdl2, sdp->sdl_len);
1644 = offsetof(struct sockaddr_dl, sdl_data[0]);
1645 sdl2->sdl_family = AF_LINK;
1646 sdl2->sdl_index = 0;
1647 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
1649 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
1650 IP_RECVIF, IPPROTO_IP);
1652 mp = &(*mp)->m_next;
1657 * XXX these routines are called from the upper part of the kernel.
1658 * They need to be locked when we remove Giant.
1660 * They could also be moved to ip_mroute.c, since all the RSVP
1661 * handling is done there already.
1663 static int ip_rsvp_on;
1664 struct socket *ip_rsvpd;
1666 ip_rsvp_init(struct socket *so)
1668 if (so->so_type != SOCK_RAW ||
1669 so->so_proto->pr_protocol != IPPROTO_RSVP)
1672 if (ip_rsvpd != NULL)
1677 * This may seem silly, but we need to be sure we don't over-increment
1678 * the RSVP counter, in case something slips up.
1693 * This may seem silly, but we need to be sure we don't over-decrement
1694 * the RSVP counter, in case something slips up.
1704 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */
1706 if (rsvp_input_p) { /* call the real one if loaded */
1707 rsvp_input_p(m, off);
1711 /* Can still get packets with rsvp_on = 0 if there is a local member
1712 * of the group to which the RSVP packet is addressed. But in this
1713 * case we want to throw the packet away.
1721 if (ip_rsvpd != NULL) {
1725 /* Drop the packet */