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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12 * notice, this list of conditions and the following disclaimer.
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17 * contributors may be used to endorse or promote products derived
18 * from this software without specific, prior written permission.
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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);
400 * XXX watch out this one. It is perhaps used as a cache for
401 * the most recently used route ? it is cleared in in_addroute()
402 * when a new route is successfully created.
404 struct route ipforward_rt[MAXCPU];
406 /* Do transport protocol processing. */
408 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip)
410 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]];
413 * Switch out to protocol's input routine.
416 pr->pr_input(m, hlen, ip->ip_p);
421 transport_processing_handler(netmsg_t netmsg)
423 struct netmsg_packet *pmsg = (struct netmsg_packet *)netmsg;
427 ip = mtod(pmsg->nm_packet, struct ip *);
428 hlen = pmsg->nm_netmsg.nm_lmsg.u.ms_result;
430 transport_processing_oncpu(pmsg->nm_packet, hlen, ip);
431 /* netmsg was embedded in the mbuf, do not reply! */
435 ip_input_handler(struct netmsg *msg0)
437 struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet;
440 /* msg0 was embedded in the mbuf, do not reply! */
444 * IP input routine. Checksum and byte swap header. If fragmented
445 * try to reassemble. Process options. Pass to next level.
448 ip_input(struct mbuf *m)
451 struct in_ifaddr *ia = NULL;
452 struct in_ifaddr_container *iac;
455 struct in_addr pkt_dst;
456 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */
457 boolean_t needredispatch = FALSE;
458 struct in_addr odst; /* original dst address(NAT) */
460 struct sockaddr_in *next_hop = NULL;
462 struct tdb_ident *tdbi;
463 struct secpolicy *sp;
469 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
471 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
472 KKASSERT(mtag != NULL);
473 next_hop = m_tag_data(mtag);
476 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
477 /* dummynet already filtered us */
478 ip = mtod(m, struct ip *);
479 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
485 /* length checks already done in ip_mport() */
486 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
487 ip = mtod(m, struct ip *);
489 if (IP_VHL_V(ip->ip_vhl) != IPVERSION) {
490 ipstat.ips_badvers++;
494 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
495 /* length checks already done in ip_mport() */
496 KASSERT(hlen >= sizeof(struct ip), ("IP header len too small"));
497 KASSERT(m->m_len >= hlen, ("complete IP header not in one mbuf"));
499 /* 127/8 must not appear on wire - RFC1122 */
500 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
501 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
502 if (!(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) {
503 ipstat.ips_badaddr++;
508 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
509 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
511 if (hlen == sizeof(struct ip))
512 sum = in_cksum_hdr(ip);
514 sum = in_cksum(m, hlen);
522 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) {
523 /* packet is dropped by traffic conditioner */
528 * Convert fields to host representation.
530 ip->ip_len = ntohs(ip->ip_len);
531 ip->ip_off = ntohs(ip->ip_off);
533 /* length checks already done in ip_mport() */
534 KASSERT(ip->ip_len >= hlen, ("total length less then header length"));
535 KASSERT(m->m_pkthdr.len >= ip->ip_len, ("mbuf too short"));
538 * Trim mbufs if longer than the IP header would have us expect.
540 if (m->m_pkthdr.len > ip->ip_len) {
541 if (m->m_len == m->m_pkthdr.len) {
542 m->m_len = ip->ip_len;
543 m->m_pkthdr.len = ip->ip_len;
545 m_adj(m, ip->ip_len - m->m_pkthdr.len);
548 #if defined(IPSEC) && !defined(IPSEC_FILTERGIF)
550 * Bypass packet filtering for packets from a tunnel (gif).
552 if (ipsec_gethist(m, NULL))
558 * Right now when no processing on packet has done
559 * and it is still fresh out of network we do our black
561 * - Firewall: deny/allow/divert
562 * - Xlate: translate packet's addr/port (NAT).
563 * - Pipe: pass pkt through dummynet.
564 * - Wrap: fake packet's addr/port <unimpl.>
565 * - Encapsulate: put it in another IP and send out. <unimp.>
570 * If we've been forwarded from the output side, then
571 * skip the firewall a second time
573 if (next_hop != NULL)
577 if (!pfil_has_hooks(&inet_pfil_hook)) {
578 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
580 * Strip dummynet tags from stranded packets
582 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
583 KKASSERT(mtag != NULL);
584 m_tag_delete(m, mtag);
585 m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED;
591 * Run through list of hooks for input packets.
593 * NB: Beware of the destination address changing (e.g.
594 * by NAT rewriting). When this happens, tell
595 * ip_forward to do the right thing.
598 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN))
600 if (m == NULL) /* consumed by filter */
602 ip = mtod(m, struct ip *);
603 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
604 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr);
606 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
607 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
608 KKASSERT(mtag != NULL);
609 next_hop = m_tag_data(mtag);
611 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
615 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) {
616 needredispatch = TRUE;
617 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH;
621 * Process options and, if not destined for us,
622 * ship it on. ip_dooptions returns 1 when an
623 * error was detected (causing an icmp message
624 * to be sent and the original packet to be freed).
626 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop))
629 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
630 * matter if it is destined to another node, or whether it is
631 * a multicast one, RSVP wants it! and prevents it from being forwarded
632 * anywhere else. Also checks if the rsvp daemon is running before
633 * grabbing the packet.
635 if (rsvp_on && ip->ip_p == IPPROTO_RSVP)
639 * Check our list of addresses, to see if the packet is for us.
640 * If we don't have any addresses, assume any unicast packet
641 * we receive might be for us (and let the upper layers deal
644 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) &&
645 !(m->m_flags & (M_MCAST | M_BCAST)))
649 * Cache the destination address of the packet; this may be
650 * changed by use of 'ipfw fwd'.
652 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
655 * Enable a consistency check between the destination address
656 * and the arrival interface for a unicast packet (the RFC 1122
657 * strong ES model) if IP forwarding is disabled and the packet
658 * is not locally generated and the packet is not subject to
661 * XXX - Checking also should be disabled if the destination
662 * address is ipnat'ed to a different interface.
664 * XXX - Checking is incompatible with IP aliases added
665 * to the loopback interface instead of the interface where
666 * the packets are received.
668 checkif = ip_checkinterface &&
670 m->m_pkthdr.rcvif != NULL &&
671 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) &&
675 * Check for exact addresses in the hash bucket.
677 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) {
681 * If the address matches, verify that the packet
682 * arrived via the correct interface if checking is
685 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr &&
686 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif))
692 * Check for broadcast addresses.
694 * Only accept broadcast packets that arrive via the matching
695 * interface. Reception of forwarded directed broadcasts would
696 * be handled via ip_forward() and ether_output() with the loopback
697 * into the stack for SIMPLEX interfaces handled by ether_output().
699 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
700 struct ifaddr_container *ifac;
702 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
704 struct ifaddr *ifa = ifac->ifa;
706 if (ifa->ifa_addr == NULL) /* shutdown/startup race */
708 if (ifa->ifa_addr->sa_family != AF_INET)
711 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
714 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr)
717 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
722 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
723 struct in_multi *inm;
725 /* XXX Multicast is not MPSAFE yet */
728 if (ip_mrouter != NULL) {
730 * If we are acting as a multicast router, all
731 * incoming multicast packets are passed to the
732 * kernel-level multicast forwarding function.
733 * The packet is returned (relatively) intact; if
734 * ip_mforward() returns a non-zero value, the packet
735 * must be discarded, else it may be accepted below.
737 if (ip_mforward != NULL &&
738 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) {
740 ipstat.ips_cantforward++;
746 * The process-level routing daemon needs to receive
747 * all multicast IGMP packets, whether or not this
748 * host belongs to their destination groups.
750 if (ip->ip_p == IPPROTO_IGMP) {
754 ipstat.ips_forward++;
757 * See if we belong to the destination multicast group on the
760 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
763 ipstat.ips_notmember++;
771 if (ip->ip_dst.s_addr == INADDR_BROADCAST)
773 if (ip->ip_dst.s_addr == INADDR_ANY)
777 * FAITH(Firewall Aided Internet Translator)
779 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
781 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
789 * Not for us; forward if possible and desirable.
792 ipstat.ips_cantforward++;
797 * Enforce inbound IPsec SPD.
799 if (ipsec4_in_reject(m, NULL)) {
800 ipsecstat.in_polvio++;
805 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
808 tdbi = (struct tdb_ident *)m_tag_data(mtag);
809 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
811 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
812 IP_FORWARDING, &error);
814 if (sp == NULL) { /* NB: can happen if error */
816 /*XXX error stat???*/
817 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
822 * Check security policy against packet attributes.
824 error = ipsec_in_reject(sp, m);
828 ipstat.ips_cantforward++;
832 ip_forward(m, using_srcrt, next_hop);
839 * IPSTEALTH: Process non-routing options only
840 * if the packet is destined for us.
843 hlen > sizeof(struct ip) &&
844 ip_dooptions(m, 1, next_hop))
847 /* Count the packet in the ip address stats */
849 ia->ia_ifa.if_ipackets++;
850 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
854 * If offset or IP_MF are set, must reassemble.
855 * Otherwise, nothing need be done.
856 * (We could look in the reassembly queue to see
857 * if the packet was previously fragmented,
858 * but it's not worth the time; just let them time out.)
860 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
862 * Attempt reassembly; if it succeeds, proceed.
863 * ip_reass() will return a different mbuf.
868 ip = mtod(m, struct ip *);
870 /* Get the header length of the reassembled packet */
871 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
873 needredispatch = TRUE;
880 * enforce IPsec policy checking if we are seeing last header.
881 * note that we do not visit this with protocols with pcb layer
882 * code - like udp/tcp/raw ip.
884 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) &&
885 ipsec4_in_reject(m, NULL)) {
886 ipsecstat.in_polvio++;
892 * enforce IPsec policy checking if we are seeing last header.
893 * note that we do not visit this with protocols with pcb layer
894 * code - like udp/tcp/raw ip.
896 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) {
898 * Check if the packet has already had IPsec processing
899 * done. If so, then just pass it along. This tag gets
900 * set during AH, ESP, etc. input handling, before the
901 * packet is returned to the ip input queue for delivery.
903 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
906 tdbi = (struct tdb_ident *)m_tag_data(mtag);
907 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
909 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
910 IP_FORWARDING, &error);
914 * Check security policy against packet attributes.
916 error = ipsec_in_reject(sp, m);
919 /* XXX error stat??? */
921 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
928 #endif /* FAST_IPSEC */
930 ipstat.ips_delivered++;
931 if (needredispatch) {
932 struct netmsg_packet *pmsg;
935 ip->ip_off = htons(ip->ip_off);
936 ip->ip_len = htons(ip->ip_len);
937 port = ip_mport_in(&m);
941 pmsg = &m->m_hdr.mh_netmsg;
942 netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, MSGF_MPSAFE,
943 transport_processing_handler);
945 pmsg->nm_netmsg.nm_lmsg.u.ms_result = hlen;
947 ip = mtod(m, struct ip *);
948 ip->ip_len = ntohs(ip->ip_len);
949 ip->ip_off = ntohs(ip->ip_off);
950 lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg);
952 transport_processing_oncpu(m, hlen, ip);
961 * Take incoming datagram fragment and try to reassemble it into
962 * whole datagram. If a chain for reassembly of this datagram already
963 * exists, then it is given as fp; otherwise have to make a chain.
966 ip_reass(struct mbuf *m)
968 struct ip *ip = mtod(m, struct ip *);
969 struct mbuf *p = NULL, *q, *nq;
971 struct ipq *fp = NULL;
972 int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
976 /* If maxnipq is 0, never accept fragments. */
978 ipstat.ips_fragments++;
979 ipstat.ips_fragdropped++;
984 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
986 * Look for queue of fragments of this datagram.
988 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next)
989 if (ip->ip_id == fp->ipq_id &&
990 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
991 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
992 ip->ip_p == fp->ipq_p)
998 * Enforce upper bound on number of fragmented packets
999 * for which we attempt reassembly;
1000 * If maxnipq is -1, accept all fragments without limitation.
1002 if (nipq > maxnipq && maxnipq > 0) {
1004 * drop something from the tail of the current queue
1005 * before proceeding further
1007 if (ipq[sum].prev == &ipq[sum]) { /* gak */
1008 for (i = 0; i < IPREASS_NHASH; i++) {
1009 if (ipq[i].prev != &ipq[i]) {
1010 ipstat.ips_fragtimeout +=
1011 ipq[i].prev->ipq_nfrags;
1012 ip_freef(ipq[i].prev);
1017 ipstat.ips_fragtimeout +=
1018 ipq[sum].prev->ipq_nfrags;
1019 ip_freef(ipq[sum].prev);
1024 * Adjust ip_len to not reflect header,
1025 * convert offset of this to bytes.
1028 if (ip->ip_off & IP_MF) {
1030 * Make sure that fragments have a data length
1031 * that's a non-zero multiple of 8 bytes.
1033 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1034 ipstat.ips_toosmall++; /* XXX */
1038 m->m_flags |= M_FRAG;
1040 m->m_flags &= ~M_FRAG;
1043 ipstat.ips_fragments++;
1044 m->m_pkthdr.header = ip;
1047 * If the hardware has not done csum over this fragment
1048 * then csum_data is not valid at all.
1050 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID))
1051 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) {
1052 m->m_pkthdr.csum_data = 0;
1053 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
1057 * Presence of header sizes in mbufs
1058 * would confuse code below.
1064 * If first fragment to arrive, create a reassembly queue.
1067 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL)
1069 insque(fp, &ipq[sum]);
1072 fp->ipq_ttl = IPFRAGTTL;
1073 fp->ipq_p = ip->ip_p;
1074 fp->ipq_id = ip->ip_id;
1075 fp->ipq_src = ip->ip_src;
1076 fp->ipq_dst = ip->ip_dst;
1078 m->m_nextpkt = NULL;
1084 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
1087 * Find a segment which begins after this one does.
1089 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
1090 if (GETIP(q)->ip_off > ip->ip_off)
1094 * If there is a preceding segment, it may provide some of
1095 * our data already. If so, drop the data from the incoming
1096 * segment. If it provides all of our data, drop us, otherwise
1097 * stick new segment in the proper place.
1099 * If some of the data is dropped from the the preceding
1100 * segment, then it's checksum is invalidated.
1103 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
1105 if (i >= ip->ip_len)
1108 m->m_pkthdr.csum_flags = 0;
1112 m->m_nextpkt = p->m_nextpkt;
1115 m->m_nextpkt = fp->ipq_frags;
1120 * While we overlap succeeding segments trim them or,
1121 * if they are completely covered, dequeue them.
1123 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
1125 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
1126 if (i < GETIP(q)->ip_len) {
1127 GETIP(q)->ip_len -= i;
1128 GETIP(q)->ip_off += i;
1130 q->m_pkthdr.csum_flags = 0;
1135 ipstat.ips_fragdropped++;
1137 q->m_nextpkt = NULL;
1143 * Check for complete reassembly and perform frag per packet
1146 * Frag limiting is performed here so that the nth frag has
1147 * a chance to complete the packet before we drop the packet.
1148 * As a result, n+1 frags are actually allowed per packet, but
1149 * only n will ever be stored. (n = maxfragsperpacket.)
1153 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1154 if (GETIP(q)->ip_off != next) {
1155 if (fp->ipq_nfrags > maxfragsperpacket) {
1156 ipstat.ips_fragdropped += fp->ipq_nfrags;
1161 next += GETIP(q)->ip_len;
1163 /* Make sure the last packet didn't have the IP_MF flag */
1164 if (p->m_flags & M_FRAG) {
1165 if (fp->ipq_nfrags > maxfragsperpacket) {
1166 ipstat.ips_fragdropped += fp->ipq_nfrags;
1173 * Reassembly is complete. Make sure the packet is a sane size.
1177 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) {
1178 ipstat.ips_toolong++;
1179 ipstat.ips_fragdropped += fp->ipq_nfrags;
1185 * Concatenate fragments.
1192 q->m_nextpkt = NULL;
1193 for (q = nq; q != NULL; q = nq) {
1195 q->m_nextpkt = NULL;
1196 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1197 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1202 * Clean up the 1's complement checksum. Carry over 16 bits must
1203 * be added back. This assumes no more then 65535 packet fragments
1204 * were reassembled. A second carry can also occur (but not a third).
1206 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) +
1207 (m->m_pkthdr.csum_data >> 16);
1208 if (m->m_pkthdr.csum_data > 0xFFFF)
1209 m->m_pkthdr.csum_data -= 0xFFFF;
1212 * Create header for new ip packet by
1213 * modifying header of first packet;
1214 * dequeue and discard fragment reassembly header.
1215 * Make header visible.
1218 ip->ip_src = fp->ipq_src;
1219 ip->ip_dst = fp->ipq_dst;
1222 mpipe_free(&ipq_mpipe, fp);
1223 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2);
1224 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2);
1225 /* some debugging cruft by sklower, below, will go away soon */
1226 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
1229 for (n = m; n; n = n->m_next)
1231 m->m_pkthdr.len = plen;
1234 ipstat.ips_reassembled++;
1238 ipstat.ips_fragdropped++;
1248 * Free a fragment reassembly header and all
1249 * associated datagrams.
1252 ip_freef(struct ipq *fp)
1256 while (fp->ipq_frags) {
1258 fp->ipq_frags = q->m_nextpkt;
1259 q->m_nextpkt = NULL;
1263 mpipe_free(&ipq_mpipe, fp);
1268 * IP timer processing;
1269 * if a timer expires on a reassembly
1270 * queue, discard it.
1279 for (i = 0; i < IPREASS_NHASH; i++) {
1283 while (fp != &ipq[i]) {
1286 if (fp->prev->ipq_ttl == 0) {
1287 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags;
1293 * If we are over the maximum number of fragments
1294 * (due to the limit being lowered), drain off
1295 * enough to get down to the new limit.
1297 if (maxnipq >= 0 && nipq > maxnipq) {
1298 for (i = 0; i < IPREASS_NHASH; i++) {
1299 while (nipq > maxnipq &&
1300 (ipq[i].next != &ipq[i])) {
1301 ipstat.ips_fragdropped +=
1302 ipq[i].next->ipq_nfrags;
1303 ip_freef(ipq[i].next);
1312 * Drain off all datagram fragments.
1319 for (i = 0; i < IPREASS_NHASH; i++) {
1320 while (ipq[i].next != &ipq[i]) {
1321 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags;
1322 ip_freef(ipq[i].next);
1329 * Do option processing on a datagram,
1330 * possibly discarding it if bad options are encountered,
1331 * or forwarding it if source-routed.
1332 * The pass argument is used when operating in the IPSTEALTH
1333 * mode to tell what options to process:
1334 * [LS]SRR (pass 0) or the others (pass 1).
1335 * The reason for as many as two passes is that when doing IPSTEALTH,
1336 * non-routing options should be processed only if the packet is for us.
1337 * Returns 1 if packet has been forwarded/freed,
1338 * 0 if the packet should be processed further.
1341 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop)
1343 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET };
1344 struct ip *ip = mtod(m, struct ip *);
1346 struct in_ifaddr *ia;
1347 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB;
1348 boolean_t forward = FALSE;
1349 struct in_addr *sin, dst;
1353 cp = (u_char *)(ip + 1);
1354 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1355 for (; cnt > 0; cnt -= optlen, cp += optlen) {
1356 opt = cp[IPOPT_OPTVAL];
1357 if (opt == IPOPT_EOL)
1359 if (opt == IPOPT_NOP)
1362 if (cnt < IPOPT_OLEN + sizeof(*cp)) {
1363 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1366 optlen = cp[IPOPT_OLEN];
1367 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
1368 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1378 * Source routing with record.
1379 * Find interface with current destination address.
1380 * If none on this machine then drop if strictly routed,
1381 * or do nothing if loosely routed.
1382 * Record interface address and bring up next address
1383 * component. If strictly routed make sure next
1384 * address is on directly accessible net.
1388 if (ipstealth && pass > 0)
1390 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1391 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1394 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1395 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1398 ipaddr.sin_addr = ip->ip_dst;
1399 ia = (struct in_ifaddr *)
1400 ifa_ifwithaddr((struct sockaddr *)&ipaddr);
1402 if (opt == IPOPT_SSRR) {
1403 type = ICMP_UNREACH;
1404 code = ICMP_UNREACH_SRCFAIL;
1407 if (!ip_dosourceroute)
1408 goto nosourcerouting;
1410 * Loose routing, and not at next destination
1411 * yet; nothing to do except forward.
1415 off--; /* 0 origin */
1416 if (off > optlen - (int)sizeof(struct in_addr)) {
1418 * End of source route. Should be for us.
1420 if (!ip_acceptsourceroute)
1421 goto nosourcerouting;
1422 save_rte(m, cp, ip->ip_src);
1427 if (!ip_dosourceroute) {
1429 char buf[sizeof "aaa.bbb.ccc.ddd"];
1432 * Acting as a router, so generate ICMP
1435 strcpy(buf, inet_ntoa(ip->ip_dst));
1437 "attempted source route from %s to %s\n",
1438 inet_ntoa(ip->ip_src), buf);
1439 type = ICMP_UNREACH;
1440 code = ICMP_UNREACH_SRCFAIL;
1444 * Not acting as a router,
1448 ipstat.ips_cantforward++;
1455 * locate outgoing interface
1457 memcpy(&ipaddr.sin_addr, cp + off,
1458 sizeof ipaddr.sin_addr);
1460 if (opt == IPOPT_SSRR) {
1461 #define INA struct in_ifaddr *
1462 #define SA struct sockaddr *
1463 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr))
1465 ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1467 ia = ip_rtaddr(ipaddr.sin_addr,
1468 &ipforward_rt[mycpuid]);
1470 type = ICMP_UNREACH;
1471 code = ICMP_UNREACH_SRCFAIL;
1474 ip->ip_dst = ipaddr.sin_addr;
1475 memcpy(cp + off, &IA_SIN(ia)->sin_addr,
1476 sizeof(struct in_addr));
1477 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1479 * Let ip_intr's mcast routing check handle mcast pkts
1481 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
1485 if (ipstealth && pass == 0)
1487 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1488 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1491 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1492 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1496 * If no space remains, ignore.
1498 off--; /* 0 origin */
1499 if (off > optlen - (int)sizeof(struct in_addr))
1501 memcpy(&ipaddr.sin_addr, &ip->ip_dst,
1502 sizeof ipaddr.sin_addr);
1504 * locate outgoing interface; if we're the destination,
1505 * use the incoming interface (should be same).
1507 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL &&
1508 (ia = ip_rtaddr(ipaddr.sin_addr,
1509 &ipforward_rt[mycpuid]))
1511 type = ICMP_UNREACH;
1512 code = ICMP_UNREACH_HOST;
1515 memcpy(cp + off, &IA_SIN(ia)->sin_addr,
1516 sizeof(struct in_addr));
1517 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1521 if (ipstealth && pass == 0)
1523 code = cp - (u_char *)ip;
1524 if (optlen < 4 || optlen > 40) {
1525 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1528 if ((off = cp[IPOPT_OFFSET]) < 5) {
1529 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1532 if (off > optlen - (int)sizeof(int32_t)) {
1533 cp[IPOPT_OFFSET + 1] += (1 << 4);
1534 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) {
1535 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1540 off--; /* 0 origin */
1541 sin = (struct in_addr *)(cp + off);
1542 switch (cp[IPOPT_OFFSET + 1] & 0x0f) {
1544 case IPOPT_TS_TSONLY:
1547 case IPOPT_TS_TSANDADDR:
1548 if (off + sizeof(n_time) +
1549 sizeof(struct in_addr) > optlen) {
1550 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1553 ipaddr.sin_addr = dst;
1554 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
1558 memcpy(sin, &IA_SIN(ia)->sin_addr,
1559 sizeof(struct in_addr));
1560 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1561 off += sizeof(struct in_addr);
1564 case IPOPT_TS_PRESPEC:
1565 if (off + sizeof(n_time) +
1566 sizeof(struct in_addr) > optlen) {
1567 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1570 memcpy(&ipaddr.sin_addr, sin,
1571 sizeof(struct in_addr));
1572 if (ifa_ifwithaddr((SA)&ipaddr) == NULL)
1574 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1575 off += sizeof(struct in_addr);
1579 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip;
1583 memcpy(cp + off, &ntime, sizeof(n_time));
1584 cp[IPOPT_OFFSET] += sizeof(n_time);
1587 if (forward && ipforwarding) {
1588 ip_forward(m, TRUE, next_hop);
1593 icmp_error(m, type, code, 0, 0);
1594 ipstat.ips_badoptions++;
1599 * Given address of next destination (final or next hop),
1600 * return internet address info of interface to be used to get there.
1603 ip_rtaddr(struct in_addr dst, struct route *ro)
1605 struct sockaddr_in *sin;
1607 sin = (struct sockaddr_in *)&ro->ro_dst;
1609 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) {
1610 if (ro->ro_rt != NULL) {
1614 sin->sin_family = AF_INET;
1615 sin->sin_len = sizeof *sin;
1616 sin->sin_addr = dst;
1617 rtalloc_ign(ro, RTF_PRCLONING);
1620 if (ro->ro_rt == NULL)
1623 return (ifatoia(ro->ro_rt->rt_ifa));
1627 * Save incoming source route for use in replies,
1628 * to be picked up later by ip_srcroute if the receiver is interested.
1631 save_rte(struct mbuf *m, u_char *option, struct in_addr dst)
1634 struct ip_srcrt_opt *opt;
1637 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT);
1640 opt = m_tag_data(mtag);
1642 olen = option[IPOPT_OLEN];
1645 kprintf("save_rte: olen %d\n", olen);
1647 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) {
1651 bcopy(option, opt->ip_srcrt.srcopt, olen);
1652 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
1653 opt->ip_srcrt.dst = dst;
1654 m_tag_prepend(m, mtag);
1658 * Retrieve incoming source route for use in replies,
1659 * in the same form used by setsockopt.
1660 * The first hop is placed before the options, will be removed later.
1663 ip_srcroute(struct mbuf *m0)
1665 struct in_addr *p, *q;
1668 struct ip_srcrt_opt *opt;
1673 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL);
1676 opt = m_tag_data(mtag);
1678 if (opt->ip_nhops == 0)
1680 m = m_get(MB_DONTWAIT, MT_HEADER);
1684 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt))
1686 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
1687 m->m_len = opt->ip_nhops * sizeof(struct in_addr) +
1688 sizeof(struct in_addr) + OPTSIZ;
1691 kprintf("ip_srcroute: nhops %d mlen %d",
1692 opt->ip_nhops, m->m_len);
1697 * First save first hop for return route
1699 p = &opt->ip_srcrt.route[opt->ip_nhops - 1];
1700 *(mtod(m, struct in_addr *)) = *p--;
1703 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1707 * Copy option fields and padding (nop) to mbuf.
1709 opt->ip_srcrt.nop = IPOPT_NOP;
1710 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
1711 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop,
1713 q = (struct in_addr *)(mtod(m, caddr_t) +
1714 sizeof(struct in_addr) + OPTSIZ);
1717 * Record return path as an IP source route,
1718 * reversing the path (pointers are now aligned).
1720 while (p >= opt->ip_srcrt.route) {
1723 kprintf(" %x", ntohl(q->s_addr));
1728 * Last hop goes to final destination.
1730 *q = opt->ip_srcrt.dst;
1731 m_tag_delete(m0, mtag);
1734 kprintf(" %x\n", ntohl(q->s_addr));
1740 * Strip out IP options.
1743 ip_stripoptions(struct mbuf *m)
1746 struct ip *ip = mtod(m, struct ip *);
1750 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1751 opts = (caddr_t)(ip + 1);
1752 datalen = m->m_len - (sizeof(struct ip) + optlen);
1753 bcopy(opts + optlen, opts, datalen);
1755 if (m->m_flags & M_PKTHDR)
1756 m->m_pkthdr.len -= optlen;
1757 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2);
1760 u_char inetctlerrmap[PRC_NCMDS] = {
1762 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1763 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1764 EMSGSIZE, EHOSTUNREACH, 0, 0,
1766 ENOPROTOOPT, ECONNREFUSED
1770 * Forward a packet. If some error occurs return the sender
1771 * an icmp packet. Note we can't always generate a meaningful
1772 * icmp message because icmp doesn't have a large enough repertoire
1773 * of codes and types.
1775 * If not forwarding, just drop the packet. This could be confusing
1776 * if ipforwarding was zero but some routing protocol was advancing
1777 * us as a gateway to somewhere. However, we must let the routing
1778 * protocol deal with that.
1780 * The using_srcrt parameter indicates whether the packet is being forwarded
1781 * via a source route.
1784 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop)
1786 struct ip *ip = mtod(m, struct ip *);
1787 struct sockaddr_in *ipforward_rtaddr;
1789 int error, type = 0, code = 0, destmtu = 0;
1792 struct in_addr pkt_dst;
1793 struct route *cache_rt = &ipforward_rt[mycpuid];
1797 * Cache the destination address of the packet; this may be
1798 * changed by use of 'ipfw fwd'.
1800 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst;
1804 kprintf("forward: src %x dst %x ttl %x\n",
1805 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl);
1808 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) {
1809 ipstat.ips_cantforward++;
1813 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) {
1814 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1818 ipforward_rtaddr = (struct sockaddr_in *) &cache_rt->ro_dst;
1819 if (cache_rt->ro_rt == NULL ||
1820 ipforward_rtaddr->sin_addr.s_addr != pkt_dst.s_addr) {
1821 if (cache_rt->ro_rt != NULL) {
1822 RTFREE(cache_rt->ro_rt);
1823 cache_rt->ro_rt = NULL;
1825 ipforward_rtaddr->sin_family = AF_INET;
1826 ipforward_rtaddr->sin_len = sizeof(struct sockaddr_in);
1827 ipforward_rtaddr->sin_addr = pkt_dst;
1828 rtalloc_ign(cache_rt, RTF_PRCLONING);
1829 if (cache_rt->ro_rt == NULL) {
1830 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1834 rt = cache_rt->ro_rt;
1837 * Save the IP header and at most 8 bytes of the payload,
1838 * in case we need to generate an ICMP message to the src.
1840 * XXX this can be optimized a lot by saving the data in a local
1841 * buffer on the stack (72 bytes at most), and only allocating the
1842 * mbuf if really necessary. The vast majority of the packets
1843 * are forwarded without having to send an ICMP back (either
1844 * because unnecessary, or because rate limited), so we are
1845 * really we are wasting a lot of work here.
1847 * We don't use m_copy() because it might return a reference
1848 * to a shared cluster. Both this function and ip_output()
1849 * assume exclusive access to the IP header in `m', so any
1850 * data in a cluster may change before we reach icmp_error().
1852 MGETHDR(mcopy, MB_DONTWAIT, m->m_type);
1853 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) {
1855 * It's probably ok if the pkthdr dup fails (because
1856 * the deep copy of the tag chain failed), but for now
1857 * be conservative and just discard the copy since
1858 * code below may some day want the tags.
1863 if (mcopy != NULL) {
1864 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8,
1866 mcopy->m_pkthdr.len = mcopy->m_len;
1867 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1871 ip->ip_ttl -= IPTTLDEC;
1874 * If forwarding packet using same interface that it came in on,
1875 * perhaps should send a redirect to sender to shortcut a hop.
1876 * Only send redirect if source is sending directly to us,
1877 * and if packet was not source routed (or has any options).
1878 * Also, don't send redirect if forwarding using a default route
1879 * or a route modified by a redirect.
1881 if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1882 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) &&
1883 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY &&
1884 ipsendredirects && !using_srcrt && next_hop == NULL) {
1885 u_long src = ntohl(ip->ip_src.s_addr);
1886 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa;
1888 if (rt_ifa != NULL &&
1889 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) {
1890 if (rt->rt_flags & RTF_GATEWAY)
1891 dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1893 dest = pkt_dst.s_addr;
1895 * Router requirements says to only send
1898 type = ICMP_REDIRECT;
1899 code = ICMP_REDIRECT_HOST;
1902 kprintf("redirect (%d) to %x\n", code, dest);
1907 error = ip_output(m, NULL, cache_rt, IP_FORWARDING, NULL, NULL);
1909 ipstat.ips_forward++;
1912 ipflow_create(cache_rt, mcopy);
1915 return; /* most common case */
1917 ipstat.ips_redirectsent++;
1920 ipstat.ips_cantforward++;
1927 * Send ICMP message.
1932 case 0: /* forwarded, but need redirect */
1933 /* type, code set above */
1936 case ENETUNREACH: /* shouldn't happen, checked above */
1941 type = ICMP_UNREACH;
1942 code = ICMP_UNREACH_HOST;
1946 type = ICMP_UNREACH;
1947 code = ICMP_UNREACH_NEEDFRAG;
1950 * If the packet is routed over IPsec tunnel, tell the
1951 * originator the tunnel MTU.
1952 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
1955 if (cache_rt->ro_rt != NULL) {
1956 struct secpolicy *sp = NULL;
1961 sp = ipsec4_getpolicybyaddr(mcopy,
1967 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu;
1969 /* count IPsec header size */
1970 ipsechdr = ipsec4_hdrsiz(mcopy,
1975 * find the correct route for outer IPv4
1976 * header, compute tunnel MTU.
1979 if (sp->req != NULL && sp->req->sav != NULL &&
1980 sp->req->sav->sah != NULL) {
1981 ro = &sp->req->sav->sah->sa_route;
1982 if (ro->ro_rt != NULL &&
1983 ro->ro_rt->rt_ifp != NULL) {
1985 ro->ro_rt->rt_ifp->if_mtu;
1986 destmtu -= ipsechdr;
1995 * If the packet is routed over IPsec tunnel, tell the
1996 * originator the tunnel MTU.
1997 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
2000 if (cache_rt->ro_rt != NULL) {
2001 struct secpolicy *sp = NULL;
2006 sp = ipsec_getpolicybyaddr(mcopy,
2012 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu;
2014 /* count IPsec header size */
2015 ipsechdr = ipsec4_hdrsiz(mcopy,
2020 * find the correct route for outer IPv4
2021 * header, compute tunnel MTU.
2024 if (sp->req != NULL &&
2025 sp->req->sav != NULL &&
2026 sp->req->sav->sah != NULL) {
2027 ro = &sp->req->sav->sah->sa_route;
2028 if (ro->ro_rt != NULL &&
2029 ro->ro_rt->rt_ifp != NULL) {
2031 ro->ro_rt->rt_ifp->if_mtu;
2032 destmtu -= ipsechdr;
2039 #else /* !IPSEC && !FAST_IPSEC */
2040 if (cache_rt->ro_rt != NULL)
2041 destmtu = cache_rt->ro_rt->rt_ifp->if_mtu;
2043 ipstat.ips_cantfrag++;
2048 * A router should not generate ICMP_SOURCEQUENCH as
2049 * required in RFC1812 Requirements for IP Version 4 Routers.
2050 * Source quench could be a big problem under DoS attacks,
2051 * or if the underlying interface is rate-limited.
2052 * Those who need source quench packets may re-enable them
2053 * via the net.inet.ip.sendsourcequench sysctl.
2055 if (!ip_sendsourcequench) {
2059 type = ICMP_SOURCEQUENCH;
2064 case EACCES: /* ipfw denied packet */
2068 icmp_error(mcopy, type, code, dest, destmtu);
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 */