2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved.
3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved.
5 * This code is derived from software contributed to The DragonFly Project
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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17 * contributors may be used to endorse or promote products derived
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66 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
67 * $FreeBSD: src/sys/netinet/ip_input.c,v 1.130.2.52 2003/03/07 07:01:28 silby Exp $
68 * $DragonFly: src/sys/netinet/ip_input.c,v 1.115 2008/10/28 07:09:26 sephe Exp $
73 #include "opt_bootp.h"
76 #include "opt_ipdivert.h"
77 #include "opt_ipfilter.h"
78 #include "opt_ipstealth.h"
79 #include "opt_ipsec.h"
81 #include <sys/param.h>
82 #include <sys/systm.h>
84 #include <sys/malloc.h>
85 #include <sys/mpipe.h>
86 #include <sys/domain.h>
87 #include <sys/protosw.h>
88 #include <sys/socket.h>
90 #include <sys/globaldata.h>
91 #include <sys/thread.h>
92 #include <sys/kernel.h>
93 #include <sys/syslog.h>
94 #include <sys/sysctl.h>
95 #include <sys/in_cksum.h>
98 #include <machine/stdarg.h>
101 #include <net/if_types.h>
102 #include <net/if_var.h>
103 #include <net/if_dl.h>
104 #include <net/pfil.h>
105 #include <net/route.h>
106 #include <net/netisr.h>
108 #include <netinet/in.h>
109 #include <netinet/in_systm.h>
110 #include <netinet/in_var.h>
111 #include <netinet/ip.h>
112 #include <netinet/in_pcb.h>
113 #include <netinet/ip_var.h>
114 #include <netinet/ip_icmp.h>
115 #include <netinet/ip_divert.h>
116 #include <netinet/ip_flow.h>
118 #include <sys/thread2.h>
119 #include <sys/msgport2.h>
120 #include <net/netmsg2.h>
122 #include <sys/socketvar.h>
124 #include <net/ipfw/ip_fw.h>
125 #include <net/dummynet/ip_dummynet.h>
128 #include <netinet6/ipsec.h>
129 #include <netproto/key/key.h>
133 #include <netproto/ipsec/ipsec.h>
134 #include <netproto/ipsec/key.h>
138 static int ip_rsvp_on;
139 struct socket *ip_rsvpd;
142 TUNABLE_INT("net.inet.ip.mpsafe", &ip_mpsafe);
144 int ipforwarding = 0;
145 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
146 &ipforwarding, 0, "Enable IP forwarding between interfaces");
148 static int ipsendredirects = 1; /* XXX */
149 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
150 &ipsendredirects, 0, "Enable sending IP redirects");
152 int ip_defttl = IPDEFTTL;
153 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
154 &ip_defttl, 0, "Maximum TTL on IP packets");
156 static int ip_dosourceroute = 0;
157 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW,
158 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets");
160 static int ip_acceptsourceroute = 0;
161 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute,
162 CTLFLAG_RW, &ip_acceptsourceroute, 0,
163 "Enable accepting source routed IP packets");
165 static int ip_keepfaith = 0;
166 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
168 "Enable packet capture for FAITH IPv4->IPv6 translator daemon");
170 static int nipq = 0; /* total # of reass queues */
172 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW,
174 "Maximum number of IPv4 fragment reassembly queue entries");
176 static int maxfragsperpacket;
177 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
178 &maxfragsperpacket, 0,
179 "Maximum number of IPv4 fragments allowed per packet");
181 static int ip_sendsourcequench = 0;
182 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
183 &ip_sendsourcequench, 0,
184 "Enable the transmission of source quench packets");
186 int ip_do_randomid = 1;
187 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
189 "Assign random ip_id values");
191 * XXX - Setting ip_checkinterface mostly implements the receive side of
192 * the Strong ES model described in RFC 1122, but since the routing table
193 * and transmit implementation do not implement the Strong ES model,
194 * setting this to 1 results in an odd hybrid.
196 * XXX - ip_checkinterface currently must be disabled if you use ipnat
197 * to translate the destination address to another local interface.
199 * XXX - ip_checkinterface must be disabled if you add IP aliases
200 * to the loopback interface instead of the interface where the
201 * packets for those addresses are received.
203 static int ip_checkinterface = 0;
204 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
205 &ip_checkinterface, 0, "Verify packet arrives on correct interface");
208 static int ipprintfs = 0;
211 extern int udp_mpsafe_proto;
212 extern int tcp_mpsafe_proto;
214 extern struct domain inetdomain;
215 extern struct protosw inetsw[];
216 u_char ip_protox[IPPROTO_MAX];
217 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */
218 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU];
219 /* inet addr hash table */
220 u_long in_ifaddrhmask; /* mask for hash table */
222 struct ip_stats ipstats_percpu[MAXCPU];
225 sysctl_ipstats(SYSCTL_HANDLER_ARGS)
229 for (cpu = 0; cpu < ncpus; ++cpu) {
230 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu],
231 sizeof(struct ip_stats))))
233 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu],
234 sizeof(struct ip_stats))))
240 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW),
241 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics");
243 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
244 &ipstat, ip_stats, "IP statistics");
247 /* Packet reassembly stuff */
248 #define IPREASS_NHASH_LOG2 6
249 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
250 #define IPREASS_HMASK (IPREASS_NHASH - 1)
251 #define IPREASS_HASH(x,y) \
252 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
254 static struct ipq ipq[IPREASS_NHASH];
257 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
258 &ip_mtu, 0, "Default MTU");
262 static int ipstealth = 0;
263 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, "");
265 static const int ipstealth = 0;
268 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int);
270 struct pfil_head inet_pfil_hook;
273 * struct ip_srcrt_opt is used to store packet state while it travels
276 * XXX Note that the code even makes assumptions on the size and
277 * alignment of fields inside struct ip_srcrt so e.g. adding some
278 * fields will break the code. This needs to be fixed.
280 * We need to save the IP options in case a protocol wants to respond
281 * to an incoming packet over the same route if the packet got here
282 * using IP source routing. This allows connection establishment and
283 * maintenance when the remote end is on a network that is not known
287 struct in_addr dst; /* final destination */
288 char nop; /* one NOP to align */
289 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
290 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
293 struct ip_srcrt_opt {
295 struct ip_srcrt ip_srcrt;
298 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management");
299 static struct malloc_pipe ipq_mpipe;
301 static void save_rte(struct mbuf *, u_char *, struct in_addr);
302 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *);
303 static void ip_freef(struct ipq *);
304 static void ip_input_handler(struct netmsg *);
307 * IP initialization: fill in IP protocol switch table.
308 * All protocols not implemented in kernel go to raw IP protocol handler.
321 * Make sure we can handle a reasonable number of fragments but
322 * cap it at 4000 (XXX).
324 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq),
325 IFQ_MAXLEN, 4000, 0, NULL);
326 for (i = 0; i < ncpus; ++i) {
327 TAILQ_INIT(&in_ifaddrheads[i]);
328 in_ifaddrhashtbls[i] =
329 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask);
331 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
334 for (i = 0; i < IPPROTO_MAX; i++)
335 ip_protox[i] = pr - inetsw;
336 for (pr = inetdomain.dom_protosw;
337 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
338 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) {
339 if (pr->pr_protocol != IPPROTO_RAW)
340 ip_protox[pr->pr_protocol] = pr - inetsw;
343 switch (pr->pr_protocol) {
345 if (tcp_mpsafe_proto)
346 pr->pr_flags |= PR_MPSAFE;
350 if (udp_mpsafe_proto)
351 pr->pr_flags |= PR_MPSAFE;
357 inet_pfil_hook.ph_type = PFIL_TYPE_AF;
358 inet_pfil_hook.ph_af = AF_INET;
359 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) {
360 kprintf("%s: WARNING: unable to register pfil hook, "
361 "error %d\n", __func__, i);
364 for (i = 0; i < IPREASS_NHASH; i++)
365 ipq[i].next = ipq[i].prev = &ipq[i];
367 maxnipq = nmbclusters / 32;
368 maxfragsperpacket = 16;
370 ip_id = time_second & 0xffff;
373 * Initialize IP statistics counters for each CPU.
377 for (cpu = 0; cpu < ncpus; ++cpu) {
378 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats));
381 bzero(&ipstat, sizeof(struct ip_stats));
384 #if defined(IPSEC) || defined(FAST_IPSEC)
385 /* XXX IPSEC is not MPSAFE yet */
386 flags = NETISR_FLAG_NOTMPSAFE;
389 kprintf("ip: MPSAFE\n");
390 flags = NETISR_FLAG_MPSAFE;
392 flags = NETISR_FLAG_NOTMPSAFE;
395 netisr_register(NETISR_IP, ip_mport_in, ip_mport_pktinfo,
396 ip_input_handler, flags);
399 /* Do transport protocol processing. */
401 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip)
403 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]];
406 * Switch out to protocol's input routine.
409 pr->pr_input(m, hlen, ip->ip_p);
414 transport_processing_handler(netmsg_t netmsg)
416 struct netmsg_packet *pmsg = (struct netmsg_packet *)netmsg;
420 ip = mtod(pmsg->nm_packet, struct ip *);
421 hlen = pmsg->nm_netmsg.nm_lmsg.u.ms_result;
423 transport_processing_oncpu(pmsg->nm_packet, hlen, ip);
424 /* netmsg was embedded in the mbuf, do not reply! */
428 ip_input_handler(struct netmsg *msg0)
430 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet;
433 /* msg0 was embedded in the mbuf, do not reply! */
437 * IP input routine. Checksum and byte swap header. If fragmented
438 * try to reassemble. Process options. Pass to next level.
441 ip_input(struct mbuf *m)
444 struct in_ifaddr *ia = NULL;
445 struct in_ifaddr_container *iac;
448 struct in_addr pkt_dst;
449 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */
450 boolean_t needredispatch = FALSE;
451 struct in_addr odst; /* original dst address(NAT) */
453 struct sockaddr_in *next_hop = NULL;
455 struct tdb_ident *tdbi;
456 struct secpolicy *sp;
462 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
464 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
465 KKASSERT(mtag != NULL);
466 next_hop = m_tag_data(mtag);
469 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
470 /* dummynet already filtered us */
471 ip = mtod(m, struct ip *);
472 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
478 /* length checks already done in ip_mport() */
479 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
480 ip = mtod(m, struct ip *);
482 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
483 ipstat.ips_badvers++;
487 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
488 /* length checks already done in ip_mport() */
489 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small"));
490 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf"));
492 /* 127/8 must not appear on wire - RFC1122 */
493 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
494 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
495 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) {
496 ipstat.ips_badaddr++;
501 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
502 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
504 if (hlen == sizeof(struct ip))
505 sum = in_cksum_hdr(ip);
507 sum = in_cksum(m, hlen);
515 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) {
516 /* packet is dropped by traffic conditioner */
521 * Convert fields to host representation.
523 ip->ip_len = ntohs(ip->ip_len);
524 ip->ip_off = ntohs(ip->ip_off);
526 /* length checks already done in ip_mport() */
527 KASSERT(ip->ip_len >= hlen, ("total length less then header length"));
528 KASSERT(m->m_pkthdr.len >= ip->ip_len, ("mbuf too short"));
531 * Trim mbufs if longer than the IP header would have us expect.
533 if (m->m_pkthdr.len > ip->ip_len) {
534 if (m->m_len == m->m_pkthdr.len) {
535 m->m_len = ip->ip_len;
536 m->m_pkthdr.len = ip->ip_len;
538 m_adj(m, ip->ip_len - m->m_pkthdr.len);
541 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF)
543 * Bypass packet filtering for packets from a tunnel (gif).
545 if (ipsec_gethist(m, NULL))
551 * Right now when no processing on packet has done
552 * and it is still fresh out of network we do our black
554 * - Firewall: deny/allow/divert
555 * - Xlate: translate packet's addr/port (NAT).
556 * - Pipe: pass pkt through dummynet.
557 * - Wrap: fake packet's addr/port <unimpl.>
558 * - Encapsulate: put it in another IP and send out. <unimp.>
563 * If we've been forwarded from the output side, then
564 * skip the firewall a second time
566 if (next_hop != NULL)
570 if (!pfil_has_hooks(&inet_pfil_hook)) {
571 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
573 * Strip dummynet tags from stranded packets
575 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
576 KKASSERT(mtag != NULL);
577 m_tag_delete(m, mtag);
578 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED;
584 * Run through list of hooks for input packets.
586 * NB: Beware of the destination address changing (e.g.
587 * by NAT rewriting). When this happens, tell
588 * ip_forward to do the right thing.
591 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN))
593 if (m == NULL) /* consumed by filter */
595 ip = mtod(m, struct ip *);
596 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
597 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr);
599 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
600 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
601 KKASSERT(mtag != NULL);
602 next_hop = m_tag_data(mtag);
604 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
608 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) {
609 needredispatch = TRUE;
610 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH;
614 * Process options and, if not destined for us,
615 * ship it on. ip_dooptions returns 1 when an
616 * error was detected (causing an icmp message
617 * to be sent and the original packet to be freed).
619 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop))
622 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
623 * matter if it is destined to another node, or whether it is
624 * a multicast one, RSVP wants it! and prevents it from being forwarded
625 * anywhere else. Also checks if the rsvp daemon is running before
626 * grabbing the packet.
628 if (rsvp_on && ip->ip_p == IPPROTO_RSVP)
632 * Check our list of addresses, to see if the packet is for us.
633 * If we don't have any addresses, assume any unicast packet
634 * we receive might be for us (and let the upper layers deal
637 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) &&
638 !(m->m_flags & (M_MCAST | M_BCAST)))
642 * Cache the destination address of the packet; this may be
643 * changed by use of 'ipfw fwd'.
645 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
648 * Enable a consistency check between the destination address
649 * and the arrival interface for a unicast packet (the RFC 1122
650 * strong ES model) if IP forwarding is disabled and the packet
651 * is not locally generated and the packet is not subject to
654 * XXX - Checking also should be disabled if the destination
655 * address is ipnat'ed to a different interface.
657 * XXX - Checking is incompatible with IP aliases added
658 * to the loopback interface instead of the interface where
659 * the packets are received.
661 checkif = ip_checkinterface &&
663 m->m_pkthdr.rcvif != NULL &&
664 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) &&
668 * Check for exact addresses in the hash bucket.
670 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) {
674 * If the address matches, verify that the packet
675 * arrived via the correct interface if checking is
678 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr &&
679 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif))
685 * Check for broadcast addresses.
687 * Only accept broadcast packets that arrive via the matching
688 * interface. Reception of forwarded directed broadcasts would
689 * be handled via ip_forward() and ether_output() with the loopback
690 * into the stack for SIMPLEX interfaces handled by ether_output().
692 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
693 struct ifaddr_container *ifac;
695 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
697 struct ifaddr *ifa = ifac->ifa;
699 if (ifa->ifa_addr == NULL) /* shutdown/startup race */
701 if (ifa->ifa_addr->sa_family != AF_INET)
704 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
707 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr)
710 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
715 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
716 struct in_multi *inm;
718 /* XXX Multicast is not MPSAFE yet */
721 if (ip_mrouter != NULL) {
723 * If we are acting as a multicast router, all
724 * incoming multicast packets are passed to the
725 * kernel-level multicast forwarding function.
726 * The packet is returned (relatively) intact; if
727 * ip_mforward() returns a non-zero value, the packet
728 * must be discarded, else it may be accepted below.
730 if (ip_mforward != NULL &&
731 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) {
733 ipstat.ips_cantforward++;
739 * The process-level routing daemon needs to receive
740 * all multicast IGMP packets, whether or not this
741 * host belongs to their destination groups.
743 if (ip->ip_p == IPPROTO_IGMP) {
747 ipstat.ips_forward++;
750 * See if we belong to the destination multicast group on the
753 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
756 ipstat.ips_notmember++;
764 if (ip->ip_dst.s_addr == INADDR_BROADCAST)
766 if (ip->ip_dst.s_addr == INADDR_ANY)
770 * FAITH(Firewall Aided Internet Translator)
772 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
774 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
782 * Not for us; forward if possible and desirable.
785 ipstat.ips_cantforward++;
790 * Enforce inbound IPsec SPD.
792 if (ipsec4_in_reject(m, NULL)) {
793 ipsecstat.in_polvio++;
798 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
801 tdbi = (struct tdb_ident *)m_tag_data(mtag);
802 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
804 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
805 IP_FORWARDING, &error);
807 if (sp == NULL) { /* NB: can happen if error */
809 /*XXX error stat???*/
810 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
815 * Check security policy against packet attributes.
817 error = ipsec_in_reject(sp, m);
821 ipstat.ips_cantforward++;
825 ip_forward(m, using_srcrt, next_hop);
832 * IPSTEALTH: Process non-routing options only
833 * if the packet is destined for us.
836 hlen > sizeof(struct ip) &&
837 ip_dooptions(m, 1, next_hop))
840 /* Count the packet in the ip address stats */
842 ia->ia_ifa.if_ipackets++;
843 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
847 * If offset or IP_MF are set, must reassemble.
848 * Otherwise, nothing need be done.
849 * (We could look in the reassembly queue to see
850 * if the packet was previously fragmented,
851 * but it's not worth the time; just let them time out.)
853 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
855 * Attempt reassembly; if it succeeds, proceed.
856 * ip_reass() will return a different mbuf.
861 ip = mtod(m, struct ip *);
863 /* Get the header length of the reassembled packet */
864 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
866 needredispatch = TRUE;
873 * enforce IPsec policy checking if we are seeing last header.
874 * note that we do not visit this with protocols with pcb layer
875 * code - like udp/tcp/raw ip.
877 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) &&
878 ipsec4_in_reject(m, NULL)) {
879 ipsecstat.in_polvio++;
885 * enforce IPsec policy checking if we are seeing last header.
886 * note that we do not visit this with protocols with pcb layer
887 * code - like udp/tcp/raw ip.
889 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) {
891 * Check if the packet has already had IPsec processing
892 * done. If so, then just pass it along. This tag gets
893 * set during AH, ESP, etc. input handling, before the
894 * packet is returned to the ip input queue for delivery.
896 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
899 tdbi = (struct tdb_ident *)m_tag_data(mtag);
900 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
902 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
903 IP_FORWARDING, &error);
907 * Check security policy against packet attributes.
909 error = ipsec_in_reject(sp, m);
912 /* XXX error stat??? */
914 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
921 #endif /* FAST_IPSEC */
924 * NOTE: ip_len in host form and adjusted down by hlen for
925 * protocol processing.
927 ipstat.ips_delivered++;
928 if (needredispatch) {
929 struct netmsg_packet *pmsg;
932 ip->ip_off = htons(ip->ip_off);
933 ip->ip_len = htons(ip->ip_len + hlen);
934 port = ip_mport_in(&m);
938 pmsg = &m->m_hdr.mh_netmsg;
939 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, MSGF_MPSAFE,
940 transport_processing_handler);
942 pmsg->nm_netmsg.nm_lmsg.u.ms_result = hlen;
944 ip = mtod(m, struct ip *);
945 ip->ip_len = ntohs(ip->ip_len) - hlen;
946 ip->ip_off = ntohs(ip->ip_off);
947 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg);
949 transport_processing_oncpu(m, hlen, ip);
958 * Take incoming datagram fragment and try to reassemble it into
959 * whole datagram. If a chain for reassembly of this datagram already
960 * exists, then it is given as fp; otherwise have to make a chain.
963 ip_reass(struct mbuf *m)
965 struct ip *ip = mtod(m, struct ip *);
966 struct mbuf *p = NULL, *q, *nq;
968 struct ipq *fp = NULL;
969 int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
973 /* If maxnipq is 0, never accept fragments. */
975 ipstat.ips_fragments++;
976 ipstat.ips_fragdropped++;
981 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
983 * Look for queue of fragments of this datagram.
985 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next)
986 if (ip->ip_id == fp->ipq_id &&
987 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
988 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
989 ip->ip_p == fp->ipq_p)
995 * Enforce upper bound on number of fragmented packets
996 * for which we attempt reassembly;
997 * If maxnipq is -1, accept all fragments without limitation.
999 if (nipq > maxnipq && maxnipq > 0) {
1001 * drop something from the tail of the current queue
1002 * before proceeding further
1004 if (ipq[sum].prev == &ipq[sum]) { /* gak */
1005 for (i = 0; i < IPREASS_NHASH; i++) {
1006 if (ipq[i].prev != &ipq[i]) {
1007 ipstat.ips_fragtimeout +=
1008 ipq[i].prev->ipq_nfrags;
1009 ip_freef(ipq[i].prev);
1014 ipstat.ips_fragtimeout +=
1015 ipq[sum].prev->ipq_nfrags;
1016 ip_freef(ipq[sum].prev);
1021 * Adjust ip_len to not reflect header,
1022 * convert offset of this to bytes.
1025 if (ip->ip_off & IP_MF) {
1027 * Make sure that fragments have a data length
1028 * that's a non-zero multiple of 8 bytes.
1030 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1031 ipstat.ips_toosmall++; /* XXX */
1035 m->m_flags |= M_FRAG;
1037 m->m_flags &= ~M_FRAG;
1040 ipstat.ips_fragments++;
1041 m->m_pkthdr.header = ip;
1044 * If the hardware has not done csum over this fragment
1045 * then csum_data is not valid at all.
1047 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID))
1048 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) {
1049 m->m_pkthdr.csum_data = 0;
1050 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
1054 * Presence of header sizes in mbufs
1055 * would confuse code below.
1061 * If first fragment to arrive, create a reassembly queue.
1064 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL)
1066 insque(fp, &ipq[sum]);
1069 fp->ipq_ttl = IPFRAGTTL;
1070 fp->ipq_p = ip->ip_p;
1071 fp->ipq_id = ip->ip_id;
1072 fp->ipq_src = ip->ip_src;
1073 fp->ipq_dst = ip->ip_dst;
1075 m->m_nextpkt = NULL;
1081 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
1084 * Find a segment which begins after this one does.
1086 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
1087 if (GETIP(q)->ip_off > ip->ip_off)
1091 * If there is a preceding segment, it may provide some of
1092 * our data already. If so, drop the data from the incoming
1093 * segment. If it provides all of our data, drop us, otherwise
1094 * stick new segment in the proper place.
1096 * If some of the data is dropped from the the preceding
1097 * segment, then it's checksum is invalidated.
1100 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
1102 if (i >= ip->ip_len)
1105 m->m_pkthdr.csum_flags = 0;
1109 m->m_nextpkt = p->m_nextpkt;
1112 m->m_nextpkt = fp->ipq_frags;
1117 * While we overlap succeeding segments trim them or,
1118 * if they are completely covered, dequeue them.
1120 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
1122 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
1123 if (i < GETIP(q)->ip_len) {
1124 GETIP(q)->ip_len -= i;
1125 GETIP(q)->ip_off += i;
1127 q->m_pkthdr.csum_flags = 0;
1132 ipstat.ips_fragdropped++;
1134 q->m_nextpkt = NULL;
1140 * Check for complete reassembly and perform frag per packet
1143 * Frag limiting is performed here so that the nth frag has
1144 * a chance to complete the packet before we drop the packet.
1145 * As a result, n+1 frags are actually allowed per packet, but
1146 * only n will ever be stored. (n = maxfragsperpacket.)
1150 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1151 if (GETIP(q)->ip_off != next) {
1152 if (fp->ipq_nfrags > maxfragsperpacket) {
1153 ipstat.ips_fragdropped += fp->ipq_nfrags;
1158 next += GETIP(q)->ip_len;
1160 /* Make sure the last packet didn't have the IP_MF flag */
1161 if (p->m_flags & M_FRAG) {
1162 if (fp->ipq_nfrags > maxfragsperpacket) {
1163 ipstat.ips_fragdropped += fp->ipq_nfrags;
1170 * Reassembly is complete. Make sure the packet is a sane size.
1174 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) {
1175 ipstat.ips_toolong++;
1176 ipstat.ips_fragdropped += fp->ipq_nfrags;
1182 * Concatenate fragments.
1189 q->m_nextpkt = NULL;
1190 for (q = nq; q != NULL; q = nq) {
1192 q->m_nextpkt = NULL;
1193 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1194 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1199 * Clean up the 1's complement checksum. Carry over 16 bits must
1200 * be added back. This assumes no more then 65535 packet fragments
1201 * were reassembled. A second carry can also occur (but not a third).
1203 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) +
1204 (m->m_pkthdr.csum_data >> 16);
1205 if (m->m_pkthdr.csum_data > 0xFFFF)
1206 m->m_pkthdr.csum_data -= 0xFFFF;
1209 * Create header for new ip packet by
1210 * modifying header of first packet;
1211 * dequeue and discard fragment reassembly header.
1212 * Make header visible.
1215 ip->ip_src = fp->ipq_src;
1216 ip->ip_dst = fp->ipq_dst;
1219 mpipe_free(&ipq_mpipe, fp);
1220 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2);
1221 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2);
1222 /* some debugging cruft by sklower, below, will go away soon */
1223 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
1226 for (n = m; n; n = n->m_next)
1228 m->m_pkthdr.len = plen;
1231 ipstat.ips_reassembled++;
1235 ipstat.ips_fragdropped++;
1245 * Free a fragment reassembly header and all
1246 * associated datagrams.
1249 ip_freef(struct ipq *fp)
1253 while (fp->ipq_frags) {
1255 fp->ipq_frags = q->m_nextpkt;
1256 q->m_nextpkt = NULL;
1260 mpipe_free(&ipq_mpipe, fp);
1265 * IP timer processing;
1266 * if a timer expires on a reassembly
1267 * queue, discard it.
1276 for (i = 0; i < IPREASS_NHASH; i++) {
1280 while (fp != &ipq[i]) {
1283 if (fp->prev->ipq_ttl == 0) {
1284 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags;
1290 * If we are over the maximum number of fragments
1291 * (due to the limit being lowered), drain off
1292 * enough to get down to the new limit.
1294 if (maxnipq >= 0 && nipq > maxnipq) {
1295 for (i = 0; i < IPREASS_NHASH; i++) {
1296 while (nipq > maxnipq &&
1297 (ipq[i].next != &ipq[i])) {
1298 ipstat.ips_fragdropped +=
1299 ipq[i].next->ipq_nfrags;
1300 ip_freef(ipq[i].next);
1309 * Drain off all datagram fragments.
1316 for (i = 0; i < IPREASS_NHASH; i++) {
1317 while (ipq[i].next != &ipq[i]) {
1318 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags;
1319 ip_freef(ipq[i].next);
1326 * Do option processing on a datagram,
1327 * possibly discarding it if bad options are encountered,
1328 * or forwarding it if source-routed.
1329 * The pass argument is used when operating in the IPSTEALTH
1330 * mode to tell what options to process:
1331 * [LS]SRR (pass 0) or the others (pass 1).
1332 * The reason for as many as two passes is that when doing IPSTEALTH,
1333 * non-routing options should be processed only if the packet is for us.
1334 * Returns 1 if packet has been forwarded/freed,
1335 * 0 if the packet should be processed further.
1338 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop)
1340 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET };
1341 struct ip *ip = mtod(m, struct ip *);
1343 struct in_ifaddr *ia;
1344 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB;
1345 boolean_t forward = FALSE;
1346 struct in_addr *sin, dst;
1350 cp = (u_char *)(ip + 1);
1351 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1352 for (; cnt > 0; cnt -= optlen, cp += optlen) {
1353 opt = cp[IPOPT_OPTVAL];
1354 if (opt == IPOPT_EOL)
1356 if (opt == IPOPT_NOP)
1359 if (cnt < IPOPT_OLEN + sizeof(*cp)) {
1360 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1363 optlen = cp[IPOPT_OLEN];
1364 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
1365 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1375 * Source routing with record.
1376 * Find interface with current destination address.
1377 * If none on this machine then drop if strictly routed,
1378 * or do nothing if loosely routed.
1379 * Record interface address and bring up next address
1380 * component. If strictly routed make sure next
1381 * address is on directly accessible net.
1385 if (ipstealth && pass > 0)
1387 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1388 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1391 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1392 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1395 ipaddr.sin_addr = ip->ip_dst;
1396 ia = (struct in_ifaddr *)
1397 ifa_ifwithaddr((struct sockaddr *)&ipaddr);
1399 if (opt == IPOPT_SSRR) {
1400 type = ICMP_UNREACH;
1401 code = ICMP_UNREACH_SRCFAIL;
1404 if (!ip_dosourceroute)
1405 goto nosourcerouting;
1407 * Loose routing, and not at next destination
1408 * yet; nothing to do except forward.
1412 off--; /* 0 origin */
1413 if (off > optlen - (int)sizeof(struct in_addr)) {
1415 * End of source route. Should be for us.
1417 if (!ip_acceptsourceroute)
1418 goto nosourcerouting;
1419 save_rte(m, cp, ip->ip_src);
1424 if (!ip_dosourceroute) {
1426 char buf[sizeof "aaa.bbb.ccc.ddd"];
1429 * Acting as a router, so generate ICMP
1432 strcpy(buf, inet_ntoa(ip->ip_dst));
1434 "attempted source route from %s to %s\n",
1435 inet_ntoa(ip->ip_src), buf);
1436 type = ICMP_UNREACH;
1437 code = ICMP_UNREACH_SRCFAIL;
1441 * Not acting as a router,
1445 ipstat.ips_cantforward++;
1452 * locate outgoing interface
1454 memcpy(&ipaddr.sin_addr, cp + off,
1455 sizeof ipaddr.sin_addr);
1457 if (opt == IPOPT_SSRR) {
1458 #define INA struct in_ifaddr *
1459 #define SA struct sockaddr *
1460 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr))
1462 ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1464 ia = ip_rtaddr(ipaddr.sin_addr, NULL);
1467 type = ICMP_UNREACH;
1468 code = ICMP_UNREACH_SRCFAIL;
1471 ip->ip_dst = ipaddr.sin_addr;
1472 memcpy(cp + off, &IA_SIN(ia)->sin_addr,
1473 sizeof(struct in_addr));
1474 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1476 * Let ip_intr's mcast routing check handle mcast pkts
1478 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
1482 if (ipstealth && pass == 0)
1484 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1485 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1488 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1489 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1493 * If no space remains, ignore.
1495 off--; /* 0 origin */
1496 if (off > optlen - (int)sizeof(struct in_addr))
1498 memcpy(&ipaddr.sin_addr, &ip->ip_dst,
1499 sizeof ipaddr.sin_addr);
1501 * locate outgoing interface; if we're the destination,
1502 * use the incoming interface (should be same).
1504 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL &&
1505 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) {
1506 type = ICMP_UNREACH;
1507 code = ICMP_UNREACH_HOST;
1510 memcpy(cp + off, &IA_SIN(ia)->sin_addr,
1511 sizeof(struct in_addr));
1512 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1516 if (ipstealth && pass == 0)
1518 code = cp - (u_char *)ip;
1519 if (optlen < 4 || optlen > 40) {
1520 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1523 if ((off = cp[IPOPT_OFFSET]) < 5) {
1524 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1527 if (off > optlen - (int)sizeof(int32_t)) {
1528 cp[IPOPT_OFFSET + 1] += (1 << 4);
1529 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) {
1530 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1535 off--; /* 0 origin */
1536 sin = (struct in_addr *)(cp + off);
1537 switch (cp[IPOPT_OFFSET + 1] & 0x0f) {
1539 case IPOPT_TS_TSONLY:
1542 case IPOPT_TS_TSANDADDR:
1543 if (off + sizeof(n_time) +
1544 sizeof(struct in_addr) > optlen) {
1545 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1548 ipaddr.sin_addr = dst;
1549 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
1553 memcpy(sin, &IA_SIN(ia)->sin_addr,
1554 sizeof(struct in_addr));
1555 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1556 off += sizeof(struct in_addr);
1559 case IPOPT_TS_PRESPEC:
1560 if (off + sizeof(n_time) +
1561 sizeof(struct in_addr) > optlen) {
1562 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1565 memcpy(&ipaddr.sin_addr, sin,
1566 sizeof(struct in_addr));
1567 if (ifa_ifwithaddr((SA)&ipaddr) == NULL)
1569 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1570 off += sizeof(struct in_addr);
1574 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip;
1578 memcpy(cp + off, &ntime, sizeof(n_time));
1579 cp[IPOPT_OFFSET] += sizeof(n_time);
1582 if (forward && ipforwarding) {
1583 ip_forward(m, TRUE, next_hop);
1588 icmp_error(m, type, code, 0, 0);
1589 ipstat.ips_badoptions++;
1594 * Given address of next destination (final or next hop),
1595 * return internet address info of interface to be used to get there.
1598 ip_rtaddr(struct in_addr dst, struct route *ro0)
1600 struct route sro, *ro;
1601 struct sockaddr_in *sin;
1602 struct in_ifaddr *ia;
1607 bzero(&sro, sizeof(sro));
1611 sin = (struct sockaddr_in *)&ro->ro_dst;
1613 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) {
1614 if (ro->ro_rt != NULL) {
1618 sin->sin_family = AF_INET;
1619 sin->sin_len = sizeof *sin;
1620 sin->sin_addr = dst;
1621 rtalloc_ign(ro, RTF_PRCLONING);
1624 if (ro->ro_rt == NULL)
1627 ia = ifatoia(ro->ro_rt->rt_ifa);
1635 * Save incoming source route for use in replies,
1636 * to be picked up later by ip_srcroute if the receiver is interested.
1639 save_rte(struct mbuf *m, u_char *option, struct in_addr dst)
1642 struct ip_srcrt_opt *opt;
1645 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT);
1648 opt = m_tag_data(mtag);
1650 olen = option[IPOPT_OLEN];
1653 kprintf("save_rte: olen %d\n", olen);
1655 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) {
1659 bcopy(option, opt->ip_srcrt.srcopt, olen);
1660 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
1661 opt->ip_srcrt.dst = dst;
1662 m_tag_prepend(m, mtag);
1666 * Retrieve incoming source route for use in replies,
1667 * in the same form used by setsockopt.
1668 * The first hop is placed before the options, will be removed later.
1671 ip_srcroute(struct mbuf *m0)
1673 struct in_addr *p, *q;
1676 struct ip_srcrt_opt *opt;
1681 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL);
1684 opt = m_tag_data(mtag);
1686 if (opt->ip_nhops == 0)
1688 m = m_get(MB_DONTWAIT, MT_HEADER);
1692 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt))
1694 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
1695 m->m_len = opt->ip_nhops * sizeof(struct in_addr) +
1696 sizeof(struct in_addr) + OPTSIZ;
1699 kprintf("ip_srcroute: nhops %d mlen %d",
1700 opt->ip_nhops, m->m_len);
1705 * First save first hop for return route
1707 p = &opt->ip_srcrt.route[opt->ip_nhops - 1];
1708 *(mtod(m, struct in_addr *)) = *p--;
1711 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1715 * Copy option fields and padding (nop) to mbuf.
1717 opt->ip_srcrt.nop = IPOPT_NOP;
1718 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
1719 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop,
1721 q = (struct in_addr *)(mtod(m, caddr_t) +
1722 sizeof(struct in_addr) + OPTSIZ);
1725 * Record return path as an IP source route,
1726 * reversing the path (pointers are now aligned).
1728 while (p >= opt->ip_srcrt.route) {
1731 kprintf(" %x", ntohl(q->s_addr));
1736 * Last hop goes to final destination.
1738 *q = opt->ip_srcrt.dst;
1739 m_tag_delete(m0, mtag);
1742 kprintf(" %x\n", ntohl(q->s_addr));
1748 * Strip out IP options.
1751 ip_stripoptions(struct mbuf *m)
1754 struct ip *ip = mtod(m, struct ip *);
1758 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1759 opts = (caddr_t)(ip + 1);
1760 datalen = m->m_len - (sizeof(struct ip) + optlen);
1761 bcopy(opts + optlen, opts, datalen);
1763 if (m->m_flags & M_PKTHDR)
1764 m->m_pkthdr.len -= optlen;
1765 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2);
1768 u_char inetctlerrmap[PRC_NCMDS] = {
1770 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1771 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1772 EMSGSIZE, EHOSTUNREACH, 0, 0,
1774 ENOPROTOOPT, ECONNREFUSED
1778 * Forward a packet. If some error occurs return the sender
1779 * an icmp packet. Note we can't always generate a meaningful
1780 * icmp message because icmp doesn't have a large enough repertoire
1781 * of codes and types.
1783 * If not forwarding, just drop the packet. This could be confusing
1784 * if ipforwarding was zero but some routing protocol was advancing
1785 * us as a gateway to somewhere. However, we must let the routing
1786 * protocol deal with that.
1788 * The using_srcrt parameter indicates whether the packet is being forwarded
1789 * via a source route.
1792 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop)
1794 struct ip *ip = mtod(m, struct ip *);
1796 struct route fwd_ro;
1797 int error, type = 0, code = 0, destmtu = 0;
1800 struct in_addr pkt_dst;
1804 * Cache the destination address of the packet; this may be
1805 * changed by use of 'ipfw fwd'.
1807 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst;
1811 kprintf("forward: src %x dst %x ttl %x\n",
1812 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl);
1815 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) {
1816 ipstat.ips_cantforward++;
1820 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) {
1821 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1825 bzero(&fwd_ro, sizeof(fwd_ro));
1826 ip_rtaddr(pkt_dst, &fwd_ro);
1827 if (fwd_ro.ro_rt == NULL) {
1828 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1834 * Save the IP header and at most 8 bytes of the payload,
1835 * in case we need to generate an ICMP message to the src.
1837 * XXX this can be optimized a lot by saving the data in a local
1838 * buffer on the stack (72 bytes at most), and only allocating the
1839 * mbuf if really necessary. The vast majority of the packets
1840 * are forwarded without having to send an ICMP back (either
1841 * because unnecessary, or because rate limited), so we are
1842 * really we are wasting a lot of work here.
1844 * We don't use m_copy() because it might return a reference
1845 * to a shared cluster. Both this function and ip_output()
1846 * assume exclusive access to the IP header in `m', so any
1847 * data in a cluster may change before we reach icmp_error().
1849 MGETHDR(mcopy, MB_DONTWAIT, m->m_type);
1850 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) {
1852 * It's probably ok if the pkthdr dup fails (because
1853 * the deep copy of the tag chain failed), but for now
1854 * be conservative and just discard the copy since
1855 * code below may some day want the tags.
1860 if (mcopy != NULL) {
1861 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8,
1863 mcopy->m_pkthdr.len = mcopy->m_len;
1864 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1868 ip->ip_ttl -= IPTTLDEC;
1871 * If forwarding packet using same interface that it came in on,
1872 * perhaps should send a redirect to sender to shortcut a hop.
1873 * Only send redirect if source is sending directly to us,
1874 * and if packet was not source routed (or has any options).
1875 * Also, don't send redirect if forwarding using a default route
1876 * or a route modified by a redirect.
1878 if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1879 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) &&
1880 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY &&
1881 ipsendredirects && !using_srcrt && next_hop == NULL) {
1882 u_long src = ntohl(ip->ip_src.s_addr);
1883 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa;
1885 if (rt_ifa != NULL &&
1886 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) {
1887 if (rt->rt_flags & RTF_GATEWAY)
1888 dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1890 dest = pkt_dst.s_addr;
1892 * Router requirements says to only send
1895 type = ICMP_REDIRECT;
1896 code = ICMP_REDIRECT_HOST;
1899 kprintf("redirect (%d) to %x\n", code, dest);
1904 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL);
1906 ipstat.ips_forward++;
1909 ipflow_create(&fwd_ro, mcopy);
1914 ipstat.ips_redirectsent++;
1917 ipstat.ips_cantforward++;
1924 * Send ICMP message.
1929 case 0: /* forwarded, but need redirect */
1930 /* type, code set above */
1933 case ENETUNREACH: /* shouldn't happen, checked above */
1938 type = ICMP_UNREACH;
1939 code = ICMP_UNREACH_HOST;
1943 type = ICMP_UNREACH;
1944 code = ICMP_UNREACH_NEEDFRAG;
1947 * If the packet is routed over IPsec tunnel, tell the
1948 * originator the tunnel MTU.
1949 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
1952 if (fwd_ro.ro_rt != NULL) {
1953 struct secpolicy *sp = NULL;
1958 sp = ipsec4_getpolicybyaddr(mcopy,
1964 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu;
1966 /* count IPsec header size */
1967 ipsechdr = ipsec4_hdrsiz(mcopy,
1972 * find the correct route for outer IPv4
1973 * header, compute tunnel MTU.
1976 if (sp->req != NULL && sp->req->sav != NULL &&
1977 sp->req->sav->sah != NULL) {
1978 ro = &sp->req->sav->sah->sa_route;
1979 if (ro->ro_rt != NULL &&
1980 ro->ro_rt->rt_ifp != NULL) {
1982 ro->ro_rt->rt_ifp->if_mtu;
1983 destmtu -= ipsechdr;
1992 * If the packet is routed over IPsec tunnel, tell the
1993 * originator the tunnel MTU.
1994 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
1997 if (fwd_ro.ro_rt != NULL) {
1998 struct secpolicy *sp = NULL;
2003 sp = ipsec_getpolicybyaddr(mcopy,
2009 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu;
2011 /* count IPsec header size */
2012 ipsechdr = ipsec4_hdrsiz(mcopy,
2017 * find the correct route for outer IPv4
2018 * header, compute tunnel MTU.
2021 if (sp->req != NULL &&
2022 sp->req->sav != NULL &&
2023 sp->req->sav->sah != NULL) {
2024 ro = &sp->req->sav->sah->sa_route;
2025 if (ro->ro_rt != NULL &&
2026 ro->ro_rt->rt_ifp != NULL) {
2028 ro->ro_rt->rt_ifp->if_mtu;
2029 destmtu -= ipsechdr;
2036 #else /* !IPSEC && !FAST_IPSEC */
2037 if (fwd_ro.ro_rt != NULL)
2038 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu;
2040 ipstat.ips_cantfrag++;
2045 * A router should not generate ICMP_SOURCEQUENCH as
2046 * required in RFC1812 Requirements for IP Version 4 Routers.
2047 * Source quench could be a big problem under DoS attacks,
2048 * or if the underlying interface is rate-limited.
2049 * Those who need source quench packets may re-enable them
2050 * via the net.inet.ip.sendsourcequench sysctl.
2052 if (!ip_sendsourcequench) {
2056 type = ICMP_SOURCEQUENCH;
2061 case EACCES: /* ipfw denied packet */
2065 icmp_error(mcopy, type, code, dest, destmtu);
2067 if (fwd_ro.ro_rt != NULL)
2068 RTFREE(fwd_ro.ro_rt);
2072 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
2075 if (inp->inp_socket->so_options & SO_TIMESTAMP) {
2079 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
2080 SCM_TIMESTAMP, SOL_SOCKET);
2082 mp = &(*mp)->m_next;
2084 if (inp->inp_flags & INP_RECVDSTADDR) {
2085 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
2086 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
2088 mp = &(*mp)->m_next;
2090 if (inp->inp_flags & INP_RECVTTL) {
2091 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl,
2092 sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
2094 mp = &(*mp)->m_next;
2098 * Moving these out of udp_input() made them even more broken
2099 * than they already were.
2101 /* options were tossed already */
2102 if (inp->inp_flags & INP_RECVOPTS) {
2103 *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
2104 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
2106 mp = &(*mp)->m_next;
2108 /* ip_srcroute doesn't do what we want here, need to fix */
2109 if (inp->inp_flags & INP_RECVRETOPTS) {
2110 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m),
2111 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
2113 mp = &(*mp)->m_next;
2116 if (inp->inp_flags & INP_RECVIF) {
2119 struct sockaddr_dl sdl;
2122 struct sockaddr_dl *sdp;
2123 struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
2125 if (((ifp = m->m_pkthdr.rcvif)) &&
2126 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) {
2127 sdp = IF_LLSOCKADDR(ifp);
2129 * Change our mind and don't try copy.
2131 if ((sdp->sdl_family != AF_LINK) ||
2132 (sdp->sdl_len > sizeof(sdlbuf))) {
2135 bcopy(sdp, sdl2, sdp->sdl_len);
2139 offsetof(struct sockaddr_dl, sdl_data[0]);
2140 sdl2->sdl_family = AF_LINK;
2141 sdl2->sdl_index = 0;
2142 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
2144 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
2145 IP_RECVIF, IPPROTO_IP);
2147 mp = &(*mp)->m_next;
2152 * XXX these routines are called from the upper part of the kernel.
2154 * They could also be moved to ip_mroute.c, since all the RSVP
2155 * handling is done there already.
2158 ip_rsvp_init(struct socket *so)
2160 if (so->so_type != SOCK_RAW ||
2161 so->so_proto->pr_protocol != IPPROTO_RSVP)
2164 if (ip_rsvpd != NULL)
2169 * This may seem silly, but we need to be sure we don't over-increment
2170 * the RSVP counter, in case something slips up.
2185 * This may seem silly, but we need to be sure we don't over-decrement
2186 * the RSVP counter, in case something slips up.
2196 rsvp_input(struct mbuf *m, ...) /* XXX must fixup manually */
2202 off = __va_arg(ap, int);
2203 proto = __va_arg(ap, int);
2206 if (rsvp_input_p) { /* call the real one if loaded */
2207 rsvp_input_p(m, off, proto);
2211 /* Can still get packets with rsvp_on = 0 if there is a local member
2212 * of the group to which the RSVP packet is addressed. But in this
2213 * case we want to throw the packet away.
2221 if (ip_rsvpd != NULL) {
2222 rip_input(m, off, proto);
2225 /* Drop the packet */