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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15 * documentation and/or other materials provided with the distribution.
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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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39 * modification, are permitted provided that the following conditions
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63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 <sys/mplock2.h>
100 #include <machine/stdarg.h>
103 #include <net/if_types.h>
104 #include <net/if_var.h>
105 #include <net/if_dl.h>
106 #include <net/pfil.h>
107 #include <net/route.h>
108 #include <net/netisr.h>
110 #include <netinet/in.h>
111 #include <netinet/in_systm.h>
112 #include <netinet/in_var.h>
113 #include <netinet/ip.h>
114 #include <netinet/in_pcb.h>
115 #include <netinet/ip_var.h>
116 #include <netinet/ip_icmp.h>
117 #include <netinet/ip_divert.h>
118 #include <netinet/ip_flow.h>
120 #include <sys/thread2.h>
121 #include <sys/msgport2.h>
122 #include <net/netmsg2.h>
124 #include <sys/socketvar.h>
126 #include <net/ipfw/ip_fw.h>
127 #include <net/dummynet/ip_dummynet.h>
130 #include <netinet6/ipsec.h>
131 #include <netproto/key/key.h>
135 #include <netproto/ipsec/ipsec.h>
136 #include <netproto/ipsec/key.h>
140 static int ip_rsvp_on;
141 struct socket *ip_rsvpd;
143 int ipforwarding = 0;
144 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
145 &ipforwarding, 0, "Enable IP forwarding between interfaces");
147 static int ipsendredirects = 1; /* XXX */
148 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
149 &ipsendredirects, 0, "Enable sending IP redirects");
151 int ip_defttl = IPDEFTTL;
152 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
153 &ip_defttl, 0, "Maximum TTL on IP packets");
155 static int ip_dosourceroute = 0;
156 SYSCTL_INT(_net_inet_ip, IPCTL_SOURCEROUTE, sourceroute, CTLFLAG_RW,
157 &ip_dosourceroute, 0, "Enable forwarding source routed IP packets");
159 static int ip_acceptsourceroute = 0;
160 SYSCTL_INT(_net_inet_ip, IPCTL_ACCEPTSOURCEROUTE, accept_sourceroute,
161 CTLFLAG_RW, &ip_acceptsourceroute, 0,
162 "Enable accepting source routed IP packets");
164 static int ip_keepfaith = 0;
165 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
167 "Enable packet capture for FAITH IPv4->IPv6 translator daemon");
169 static int nipq = 0; /* total # of reass queues */
171 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_RW,
173 "Maximum number of IPv4 fragment reassembly queue entries");
175 static int maxfragsperpacket;
176 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
177 &maxfragsperpacket, 0,
178 "Maximum number of IPv4 fragments allowed per packet");
180 static int ip_sendsourcequench = 0;
181 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
182 &ip_sendsourcequench, 0,
183 "Enable the transmission of source quench packets");
185 int ip_do_randomid = 1;
186 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
188 "Assign random ip_id values");
190 * XXX - Setting ip_checkinterface mostly implements the receive side of
191 * the Strong ES model described in RFC 1122, but since the routing table
192 * and transmit implementation do not implement the Strong ES model,
193 * setting this to 1 results in an odd hybrid.
195 * XXX - ip_checkinterface currently must be disabled if you use ipnat
196 * to translate the destination address to another local interface.
198 * XXX - ip_checkinterface must be disabled if you add IP aliases
199 * to the loopback interface instead of the interface where the
200 * packets for those addresses are received.
202 static int ip_checkinterface = 0;
203 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
204 &ip_checkinterface, 0, "Verify packet arrives on correct interface");
206 static int ip_dispatch_fast = 0;
207 static int ip_dispatch_slow = 0;
208 static int ip_dispatch_recheck = 0;
209 static int ip_dispatch_software = 0;
210 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_fast_count, CTLFLAG_RD,
211 &ip_dispatch_fast, 0,
212 "Number of IP dispatches handled on current CPU");
213 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_slow_count, CTLFLAG_RD,
214 &ip_dispatch_slow, 0,
215 "Number of IP dispatches messaged to another CPU");
216 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_software_count, CTLFLAG_RD,
217 &ip_dispatch_software, 0, "");
218 SYSCTL_INT(_net_inet_ip, OID_AUTO, dispatch_recheck_count, CTLFLAG_RD,
219 &ip_dispatch_recheck, 0, "");
221 static struct lwkt_token ipq_token = LWKT_TOKEN_INITIALIZER(ipq_token);
224 static int ipprintfs = 0;
227 extern struct domain inetdomain;
228 extern struct protosw inetsw[];
229 u_char ip_protox[IPPROTO_MAX];
230 struct in_ifaddrhead in_ifaddrheads[MAXCPU]; /* first inet address */
231 struct in_ifaddrhashhead *in_ifaddrhashtbls[MAXCPU];
232 /* inet addr hash table */
233 u_long in_ifaddrhmask; /* mask for hash table */
235 struct ip_stats ipstats_percpu[MAXCPU];
238 sysctl_ipstats(SYSCTL_HANDLER_ARGS)
242 for (cpu = 0; cpu < ncpus; ++cpu) {
243 if ((error = SYSCTL_OUT(req, &ipstats_percpu[cpu],
244 sizeof(struct ip_stats))))
246 if ((error = SYSCTL_IN(req, &ipstats_percpu[cpu],
247 sizeof(struct ip_stats))))
253 SYSCTL_PROC(_net_inet_ip, IPCTL_STATS, stats, (CTLTYPE_OPAQUE | CTLFLAG_RW),
254 0, 0, sysctl_ipstats, "S,ip_stats", "IP statistics");
256 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
257 &ipstat, ip_stats, "IP statistics");
260 /* Packet reassembly stuff */
261 #define IPREASS_NHASH_LOG2 6
262 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
263 #define IPREASS_HMASK (IPREASS_NHASH - 1)
264 #define IPREASS_HASH(x,y) \
265 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
267 static struct ipq ipq[IPREASS_NHASH];
270 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
271 &ip_mtu, 0, "Default MTU");
275 static int ipstealth = 0;
276 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW, &ipstealth, 0, "");
278 static const int ipstealth = 0;
281 struct mbuf *(*ip_divert_p)(struct mbuf *, int, int);
283 struct pfil_head inet_pfil_hook;
286 * struct ip_srcrt_opt is used to store packet state while it travels
289 * XXX Note that the code even makes assumptions on the size and
290 * alignment of fields inside struct ip_srcrt so e.g. adding some
291 * fields will break the code. This needs to be fixed.
293 * We need to save the IP options in case a protocol wants to respond
294 * to an incoming packet over the same route if the packet got here
295 * using IP source routing. This allows connection establishment and
296 * maintenance when the remote end is on a network that is not known
300 struct in_addr dst; /* final destination */
301 char nop; /* one NOP to align */
302 char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
303 struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
306 struct ip_srcrt_opt {
308 struct ip_srcrt ip_srcrt;
311 static MALLOC_DEFINE(M_IPQ, "ipq", "IP Fragment Management");
312 static struct malloc_pipe ipq_mpipe;
314 static void save_rte(struct mbuf *, u_char *, struct in_addr);
315 static int ip_dooptions(struct mbuf *m, int, struct sockaddr_in *);
316 static void ip_freef(struct ipq *);
317 static void ip_input_handler(netmsg_t);
320 * IP initialization: fill in IP protocol switch table.
321 * All protocols not implemented in kernel go to raw IP protocol handler.
333 * Make sure we can handle a reasonable number of fragments but
334 * cap it at 4000 (XXX).
336 mpipe_init(&ipq_mpipe, M_IPQ, sizeof(struct ipq),
337 IFQ_MAXLEN, 4000, 0, NULL, NULL, NULL);
338 for (i = 0; i < ncpus; ++i) {
339 TAILQ_INIT(&in_ifaddrheads[i]);
340 in_ifaddrhashtbls[i] =
341 hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask);
343 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
346 for (i = 0; i < IPPROTO_MAX; i++)
347 ip_protox[i] = pr - inetsw;
348 for (pr = inetdomain.dom_protosw;
349 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
350 if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol) {
351 if (pr->pr_protocol != IPPROTO_RAW)
352 ip_protox[pr->pr_protocol] = pr - inetsw;
356 inet_pfil_hook.ph_type = PFIL_TYPE_AF;
357 inet_pfil_hook.ph_af = AF_INET;
358 if ((i = pfil_head_register(&inet_pfil_hook)) != 0) {
359 kprintf("%s: WARNING: unable to register pfil hook, "
360 "error %d\n", __func__, i);
363 for (i = 0; i < IPREASS_NHASH; i++)
364 ipq[i].next = ipq[i].prev = &ipq[i];
366 maxnipq = nmbclusters / 32;
367 maxfragsperpacket = 16;
369 ip_id = time_second & 0xffff;
372 * Initialize IP statistics counters for each CPU.
376 for (cpu = 0; cpu < ncpus; ++cpu) {
377 bzero(&ipstats_percpu[cpu], sizeof(struct ip_stats));
380 bzero(&ipstat, sizeof(struct ip_stats));
383 netisr_register(NETISR_IP, ip_input_handler, ip_cpufn_in);
386 /* Do transport protocol processing. */
388 transport_processing_oncpu(struct mbuf *m, int hlen, struct ip *ip)
390 const struct protosw *pr = &inetsw[ip_protox[ip->ip_p]];
393 * Switch out to protocol's input routine.
396 pr->pr_input(&m, &hlen, ip->ip_p);
401 transport_processing_handler(netmsg_t msg)
403 struct netmsg_packet *pmsg = &msg->packet;
407 ip = mtod(pmsg->nm_packet, struct ip *);
408 hlen = pmsg->base.lmsg.u.ms_result;
410 transport_processing_oncpu(pmsg->nm_packet, hlen, ip);
411 /* msg was embedded in the mbuf, do not reply! */
415 ip_input_handler(netmsg_t msg)
417 ip_input(msg->packet.nm_packet);
418 /* msg was embedded in the mbuf, do not reply! */
422 * IP input routine. Checksum and byte swap header. If fragmented
423 * try to reassemble. Process options. Pass to next level.
426 ip_input(struct mbuf *m)
429 struct in_ifaddr *ia = NULL;
430 struct in_ifaddr_container *iac;
433 struct in_addr pkt_dst;
434 boolean_t using_srcrt = FALSE; /* forward (by PFIL_HOOKS) */
435 struct in_addr odst; /* original dst address(NAT) */
437 struct sockaddr_in *next_hop = NULL;
440 struct tdb_ident *tdbi;
441 struct secpolicy *sp;
448 * This routine is called from numerous places which may not have
449 * characterized the packet.
451 if ((m->m_flags & M_HASH) == 0) {
452 ++ip_dispatch_software;
453 ip_cpufn(&m, 0, IP_MPORT_IN);
456 KKASSERT(m->m_flags & M_HASH);
458 ip = mtod(m, struct ip *);
461 * Pull out certain tags
463 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
465 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
466 KKASSERT(mtag != NULL);
467 next_hop = m_tag_data(mtag);
470 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
471 /* dummynet already filtered us */
472 ip = mtod(m, struct ip *);
473 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
479 /* length checks already done in ip_cpufn() */
480 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
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_cpufn() */
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_cpufn() */
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 * NOTE! If the packet is rewritten pf/ipfw/whoever must
590 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif, PFIL_IN))
592 if (m == NULL) /* consumed by filter */
594 ip = mtod(m, struct ip *);
595 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
596 using_srcrt = (odst.s_addr != ip->ip_dst.s_addr);
598 if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
599 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
600 KKASSERT(mtag != NULL);
601 next_hop = m_tag_data(mtag);
603 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
607 if (m->m_pkthdr.fw_flags & FW_MBUF_REDISPATCH) {
608 m->m_pkthdr.fw_flags &= ~FW_MBUF_REDISPATCH;
612 * Process options and, if not destined for us,
613 * ship it on. ip_dooptions returns 1 when an
614 * error was detected (causing an icmp message
615 * to be sent and the original packet to be freed).
617 if (hlen > sizeof(struct ip) && ip_dooptions(m, 0, next_hop))
620 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
621 * matter if it is destined to another node, or whether it is
622 * a multicast one, RSVP wants it! and prevents it from being forwarded
623 * anywhere else. Also checks if the rsvp daemon is running before
624 * grabbing the packet.
626 if (rsvp_on && ip->ip_p == IPPROTO_RSVP)
630 * Check our list of addresses, to see if the packet is for us.
631 * If we don't have any addresses, assume any unicast packet
632 * we receive might be for us (and let the upper layers deal
635 if (TAILQ_EMPTY(&in_ifaddrheads[mycpuid]) &&
636 !(m->m_flags & (M_MCAST | M_BCAST)))
640 * Cache the destination address of the packet; this may be
641 * changed by use of 'ipfw fwd'.
643 pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
646 * Enable a consistency check between the destination address
647 * and the arrival interface for a unicast packet (the RFC 1122
648 * strong ES model) if IP forwarding is disabled and the packet
649 * is not locally generated and the packet is not subject to
652 * XXX - Checking also should be disabled if the destination
653 * address is ipnat'ed to a different interface.
655 * XXX - Checking is incompatible with IP aliases added
656 * to the loopback interface instead of the interface where
657 * the packets are received.
659 checkif = ip_checkinterface &&
661 m->m_pkthdr.rcvif != NULL &&
662 !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) &&
666 * Check for exact addresses in the hash bucket.
668 LIST_FOREACH(iac, INADDR_HASH(pkt_dst.s_addr), ia_hash) {
672 * If the address matches, verify that the packet
673 * arrived via the correct interface if checking is
676 if (IA_SIN(ia)->sin_addr.s_addr == pkt_dst.s_addr &&
677 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif))
683 * Check for broadcast addresses.
685 * Only accept broadcast packets that arrive via the matching
686 * interface. Reception of forwarded directed broadcasts would
687 * be handled via ip_forward() and ether_output() with the loopback
688 * into the stack for SIMPLEX interfaces handled by ether_output().
690 if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
691 struct ifaddr_container *ifac;
693 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
695 struct ifaddr *ifa = ifac->ifa;
697 if (ifa->ifa_addr == NULL) /* shutdown/startup race */
699 if (ifa->ifa_addr->sa_family != AF_INET)
702 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
705 if (ia->ia_netbroadcast.s_addr == pkt_dst.s_addr)
708 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
713 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
714 struct in_multi *inm;
716 /* XXX Multicast is not MPSAFE yet */
719 if (ip_mrouter != NULL) {
721 * If we are acting as a multicast router, all
722 * incoming multicast packets are passed to the
723 * kernel-level multicast forwarding function.
724 * The packet is returned (relatively) intact; if
725 * ip_mforward() returns a non-zero value, the packet
726 * must be discarded, else it may be accepted below.
728 if (ip_mforward != NULL &&
729 ip_mforward(ip, m->m_pkthdr.rcvif, m, NULL) != 0) {
731 ipstat.ips_cantforward++;
737 * The process-level routing daemon needs to receive
738 * all multicast IGMP packets, whether or not this
739 * host belongs to their destination groups.
741 if (ip->ip_p == IPPROTO_IGMP) {
745 ipstat.ips_forward++;
748 * See if we belong to the destination multicast group on the
751 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
754 ipstat.ips_notmember++;
762 if (ip->ip_dst.s_addr == INADDR_BROADCAST)
764 if (ip->ip_dst.s_addr == INADDR_ANY)
768 * FAITH(Firewall Aided Internet Translator)
770 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
772 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
780 * Not for us; forward if possible and desirable.
783 ipstat.ips_cantforward++;
788 * Enforce inbound IPsec SPD.
790 if (ipsec4_in_reject(m, NULL)) {
791 ipsecstat.in_polvio++;
796 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
799 tdbi = (struct tdb_ident *)m_tag_data(mtag);
800 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
802 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
803 IP_FORWARDING, &error);
805 if (sp == NULL) { /* NB: can happen if error */
807 /*XXX error stat???*/
808 DPRINTF(("ip_input: no SP for forwarding\n")); /*XXX*/
813 * Check security policy against packet attributes.
815 error = ipsec_in_reject(sp, m);
819 ipstat.ips_cantforward++;
823 ip_forward(m, using_srcrt, next_hop);
830 * IPSTEALTH: Process non-routing options only
831 * if the packet is destined for us.
834 hlen > sizeof(struct ip) &&
835 ip_dooptions(m, 1, next_hop))
838 /* Count the packet in the ip address stats */
840 ia->ia_ifa.if_ipackets++;
841 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
845 * If offset or IP_MF are set, must reassemble.
846 * Otherwise, nothing need be done.
847 * (We could look in the reassembly queue to see
848 * if the packet was previously fragmented,
849 * but it's not worth the time; just let them time out.)
851 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
853 * Attempt reassembly; if it succeeds, proceed. ip_reass()
854 * will return a different mbuf.
856 * NOTE: ip_reass() returns m with M_HASH cleared to force
857 * us to recharacterize the packet.
862 ip = mtod(m, struct ip *);
864 /* Get the header length of the reassembled packet */
865 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
872 * enforce IPsec policy checking if we are seeing last header.
873 * note that we do not visit this with protocols with pcb layer
874 * code - like udp/tcp/raw ip.
876 if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) &&
877 ipsec4_in_reject(m, NULL)) {
878 ipsecstat.in_polvio++;
884 * enforce IPsec policy checking if we are seeing last header.
885 * note that we do not visit this with protocols with pcb layer
886 * code - like udp/tcp/raw ip.
888 if (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) {
890 * Check if the packet has already had IPsec processing
891 * done. If so, then just pass it along. This tag gets
892 * set during AH, ESP, etc. input handling, before the
893 * packet is returned to the ip input queue for delivery.
895 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
898 tdbi = (struct tdb_ident *)m_tag_data(mtag);
899 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
901 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
902 IP_FORWARDING, &error);
906 * Check security policy against packet attributes.
908 error = ipsec_in_reject(sp, m);
911 /* XXX error stat??? */
913 DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
920 #endif /* FAST_IPSEC */
923 * We must forward the packet to the correct protocol thread if
924 * we are not already in it.
926 * NOTE: ip_len is now in host form. ip_len is not adjusted
927 * further for protocol processing, instead we pass hlen
928 * to the protosw and let it deal with it.
930 ipstat.ips_delivered++;
932 if ((m->m_flags & M_HASH) == 0) {
933 ++ip_dispatch_recheck;
934 ip->ip_len = htons(ip->ip_len + hlen);
935 ip->ip_off = htons(ip->ip_off);
937 ip_cpufn(&m, 0, IP_MPORT_IN);
941 ip = mtod(m, struct ip *);
942 ip->ip_len = ntohs(ip->ip_len) - hlen;
943 ip->ip_off = ntohs(ip->ip_off);
944 KKASSERT(m->m_flags & M_HASH);
946 port = cpu_portfn(m->m_pkthdr.hash);
948 if (port != &curthread->td_msgport) {
949 struct netmsg_packet *pmsg;
953 pmsg = &m->m_hdr.mh_netmsg;
954 netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport,
955 0, transport_processing_handler);
957 pmsg->base.lmsg.u.ms_result = hlen;
958 lwkt_sendmsg(port, &pmsg->base.lmsg);
961 transport_processing_oncpu(m, hlen, ip);
970 * Take incoming datagram fragment and try to reassemble it into
971 * whole datagram. If a chain for reassembly of this datagram already
972 * exists, then it is given as fp; otherwise have to make a chain.
975 ip_reass(struct mbuf *m)
977 struct ip *ip = mtod(m, struct ip *);
978 struct mbuf *p = NULL, *q, *nq;
980 struct ipq *fp = NULL;
981 int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
985 /* If maxnipq is 0, never accept fragments. */
987 ipstat.ips_fragments++;
988 ipstat.ips_fragdropped++;
993 sum = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
995 * Look for queue of fragments of this datagram.
997 lwkt_gettoken(&ipq_token);
998 for (fp = ipq[sum].next; fp != &ipq[sum]; fp = fp->next) {
999 if (ip->ip_id == fp->ipq_id &&
1000 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
1001 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
1002 ip->ip_p == fp->ipq_p)
1009 * Enforce upper bound on number of fragmented packets
1010 * for which we attempt reassembly;
1011 * If maxnipq is -1, accept all fragments without limitation.
1013 if (nipq > maxnipq && maxnipq > 0) {
1015 * drop something from the tail of the current queue
1016 * before proceeding further
1018 if (ipq[sum].prev == &ipq[sum]) { /* gak */
1019 for (i = 0; i < IPREASS_NHASH; i++) {
1020 if (ipq[i].prev != &ipq[i]) {
1021 ipstat.ips_fragtimeout +=
1022 ipq[i].prev->ipq_nfrags;
1023 ip_freef(ipq[i].prev);
1028 ipstat.ips_fragtimeout +=
1029 ipq[sum].prev->ipq_nfrags;
1030 ip_freef(ipq[sum].prev);
1035 * Adjust ip_len to not reflect header,
1036 * convert offset of this to bytes.
1039 if (ip->ip_off & IP_MF) {
1041 * Make sure that fragments have a data length
1042 * that's a non-zero multiple of 8 bytes.
1044 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
1045 ipstat.ips_toosmall++; /* XXX */
1049 m->m_flags |= M_FRAG;
1051 m->m_flags &= ~M_FRAG;
1055 ipstat.ips_fragments++;
1056 m->m_pkthdr.header = ip;
1059 * If the hardware has not done csum over this fragment
1060 * then csum_data is not valid at all.
1062 if ((m->m_pkthdr.csum_flags & (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID))
1063 == (CSUM_FRAG_NOT_CHECKED | CSUM_DATA_VALID)) {
1064 m->m_pkthdr.csum_data = 0;
1065 m->m_pkthdr.csum_flags &= ~(CSUM_DATA_VALID | CSUM_PSEUDO_HDR);
1069 * Presence of header sizes in mbufs
1070 * would confuse code below.
1076 * If first fragment to arrive, create a reassembly queue.
1079 if ((fp = mpipe_alloc_nowait(&ipq_mpipe)) == NULL)
1081 insque(fp, &ipq[sum]);
1084 fp->ipq_ttl = IPFRAGTTL;
1085 fp->ipq_p = ip->ip_p;
1086 fp->ipq_id = ip->ip_id;
1087 fp->ipq_src = ip->ip_src;
1088 fp->ipq_dst = ip->ip_dst;
1090 m->m_nextpkt = NULL;
1096 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
1099 * Find a segment which begins after this one does.
1101 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1102 if (GETIP(q)->ip_off > ip->ip_off)
1107 * If there is a preceding segment, it may provide some of
1108 * our data already. If so, drop the data from the incoming
1109 * segment. If it provides all of our data, drop us, otherwise
1110 * stick new segment in the proper place.
1112 * If some of the data is dropped from the the preceding
1113 * segment, then it's checksum is invalidated.
1116 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
1118 if (i >= ip->ip_len)
1121 m->m_pkthdr.csum_flags = 0;
1125 m->m_nextpkt = p->m_nextpkt;
1128 m->m_nextpkt = fp->ipq_frags;
1133 * While we overlap succeeding segments trim them or,
1134 * if they are completely covered, dequeue them.
1136 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
1138 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
1139 if (i < GETIP(q)->ip_len) {
1140 GETIP(q)->ip_len -= i;
1141 GETIP(q)->ip_off += i;
1143 q->m_pkthdr.csum_flags = 0;
1148 ipstat.ips_fragdropped++;
1150 q->m_nextpkt = NULL;
1156 * Check for complete reassembly and perform frag per packet
1159 * Frag limiting is performed here so that the nth frag has
1160 * a chance to complete the packet before we drop the packet.
1161 * As a result, n+1 frags are actually allowed per packet, but
1162 * only n will ever be stored. (n = maxfragsperpacket.)
1166 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
1167 if (GETIP(q)->ip_off != next) {
1168 if (fp->ipq_nfrags > maxfragsperpacket) {
1169 ipstat.ips_fragdropped += fp->ipq_nfrags;
1174 next += GETIP(q)->ip_len;
1176 /* Make sure the last packet didn't have the IP_MF flag */
1177 if (p->m_flags & M_FRAG) {
1178 if (fp->ipq_nfrags > maxfragsperpacket) {
1179 ipstat.ips_fragdropped += fp->ipq_nfrags;
1186 * Reassembly is complete. Make sure the packet is a sane size.
1190 if (next + (IP_VHL_HL(ip->ip_vhl) << 2) > IP_MAXPACKET) {
1191 ipstat.ips_toolong++;
1192 ipstat.ips_fragdropped += fp->ipq_nfrags;
1198 * Concatenate fragments.
1205 q->m_nextpkt = NULL;
1206 for (q = nq; q != NULL; q = nq) {
1208 q->m_nextpkt = NULL;
1209 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1210 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1215 * Clean up the 1's complement checksum. Carry over 16 bits must
1216 * be added back. This assumes no more then 65535 packet fragments
1217 * were reassembled. A second carry can also occur (but not a third).
1219 m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) +
1220 (m->m_pkthdr.csum_data >> 16);
1221 if (m->m_pkthdr.csum_data > 0xFFFF)
1222 m->m_pkthdr.csum_data -= 0xFFFF;
1225 * Create header for new ip packet by
1226 * modifying header of first packet;
1227 * dequeue and discard fragment reassembly header.
1228 * Make header visible.
1231 ip->ip_src = fp->ipq_src;
1232 ip->ip_dst = fp->ipq_dst;
1235 mpipe_free(&ipq_mpipe, fp);
1236 m->m_len += (IP_VHL_HL(ip->ip_vhl) << 2);
1237 m->m_data -= (IP_VHL_HL(ip->ip_vhl) << 2);
1238 /* some debugging cruft by sklower, below, will go away soon */
1239 if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
1242 for (n = m; n; n = n->m_next)
1244 m->m_pkthdr.len = plen;
1248 * Reassembly complete, return the next protocol.
1250 * Be sure to clear M_HASH to force the packet
1251 * to be re-characterized.
1253 * Clear M_FRAG, we are no longer a fragment.
1255 m->m_flags &= ~(M_HASH | M_FRAG);
1257 ipstat.ips_reassembled++;
1258 lwkt_reltoken(&ipq_token);
1262 ipstat.ips_fragdropped++;
1267 lwkt_reltoken(&ipq_token);
1274 * Free a fragment reassembly header and all
1275 * associated datagrams.
1277 * Called with ipq_token held.
1280 ip_freef(struct ipq *fp)
1285 * Remove first to protect against blocking
1290 * Clean out at our leisure
1292 while (fp->ipq_frags) {
1294 fp->ipq_frags = q->m_nextpkt;
1295 q->m_nextpkt = NULL;
1298 mpipe_free(&ipq_mpipe, fp);
1303 * IP timer processing;
1304 * if a timer expires on a reassembly
1305 * queue, discard it.
1313 lwkt_gettoken(&ipq_token);
1314 for (i = 0; i < IPREASS_NHASH; i++) {
1318 while (fp != &ipq[i]) {
1321 if (fp->prev->ipq_ttl == 0) {
1322 ipstat.ips_fragtimeout += fp->prev->ipq_nfrags;
1328 * If we are over the maximum number of fragments
1329 * (due to the limit being lowered), drain off
1330 * enough to get down to the new limit.
1332 if (maxnipq >= 0 && nipq > maxnipq) {
1333 for (i = 0; i < IPREASS_NHASH; i++) {
1334 while (nipq > maxnipq &&
1335 (ipq[i].next != &ipq[i])) {
1336 ipstat.ips_fragdropped +=
1337 ipq[i].next->ipq_nfrags;
1338 ip_freef(ipq[i].next);
1342 lwkt_reltoken(&ipq_token);
1347 * Drain off all datagram fragments.
1354 lwkt_gettoken(&ipq_token);
1355 for (i = 0; i < IPREASS_NHASH; i++) {
1356 while (ipq[i].next != &ipq[i]) {
1357 ipstat.ips_fragdropped += ipq[i].next->ipq_nfrags;
1358 ip_freef(ipq[i].next);
1361 lwkt_reltoken(&ipq_token);
1366 * Do option processing on a datagram,
1367 * possibly discarding it if bad options are encountered,
1368 * or forwarding it if source-routed.
1369 * The pass argument is used when operating in the IPSTEALTH
1370 * mode to tell what options to process:
1371 * [LS]SRR (pass 0) or the others (pass 1).
1372 * The reason for as many as two passes is that when doing IPSTEALTH,
1373 * non-routing options should be processed only if the packet is for us.
1374 * Returns 1 if packet has been forwarded/freed,
1375 * 0 if the packet should be processed further.
1378 ip_dooptions(struct mbuf *m, int pass, struct sockaddr_in *next_hop)
1380 struct sockaddr_in ipaddr = { sizeof ipaddr, AF_INET };
1381 struct ip *ip = mtod(m, struct ip *);
1383 struct in_ifaddr *ia;
1384 int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB;
1385 boolean_t forward = FALSE;
1386 struct in_addr *sin, dst;
1390 cp = (u_char *)(ip + 1);
1391 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1392 for (; cnt > 0; cnt -= optlen, cp += optlen) {
1393 opt = cp[IPOPT_OPTVAL];
1394 if (opt == IPOPT_EOL)
1396 if (opt == IPOPT_NOP)
1399 if (cnt < IPOPT_OLEN + sizeof(*cp)) {
1400 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1403 optlen = cp[IPOPT_OLEN];
1404 if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
1405 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1415 * Source routing with record.
1416 * Find interface with current destination address.
1417 * If none on this machine then drop if strictly routed,
1418 * or do nothing if loosely routed.
1419 * Record interface address and bring up next address
1420 * component. If strictly routed make sure next
1421 * address is on directly accessible net.
1425 if (ipstealth && pass > 0)
1427 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1428 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1431 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1432 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1435 ipaddr.sin_addr = ip->ip_dst;
1436 ia = (struct in_ifaddr *)
1437 ifa_ifwithaddr((struct sockaddr *)&ipaddr);
1439 if (opt == IPOPT_SSRR) {
1440 type = ICMP_UNREACH;
1441 code = ICMP_UNREACH_SRCFAIL;
1444 if (!ip_dosourceroute)
1445 goto nosourcerouting;
1447 * Loose routing, and not at next destination
1448 * yet; nothing to do except forward.
1452 off--; /* 0 origin */
1453 if (off > optlen - (int)sizeof(struct in_addr)) {
1455 * End of source route. Should be for us.
1457 if (!ip_acceptsourceroute)
1458 goto nosourcerouting;
1459 save_rte(m, cp, ip->ip_src);
1464 if (!ip_dosourceroute) {
1466 char buf[sizeof "aaa.bbb.ccc.ddd"];
1469 * Acting as a router, so generate ICMP
1472 strcpy(buf, inet_ntoa(ip->ip_dst));
1474 "attempted source route from %s to %s\n",
1475 inet_ntoa(ip->ip_src), buf);
1476 type = ICMP_UNREACH;
1477 code = ICMP_UNREACH_SRCFAIL;
1481 * Not acting as a router,
1485 ipstat.ips_cantforward++;
1492 * locate outgoing interface
1494 memcpy(&ipaddr.sin_addr, cp + off,
1495 sizeof ipaddr.sin_addr);
1497 if (opt == IPOPT_SSRR) {
1498 #define INA struct in_ifaddr *
1499 #define SA struct sockaddr *
1500 if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr))
1502 ia = (INA)ifa_ifwithnet((SA)&ipaddr);
1504 ia = ip_rtaddr(ipaddr.sin_addr, NULL);
1507 type = ICMP_UNREACH;
1508 code = ICMP_UNREACH_SRCFAIL;
1511 ip->ip_dst = ipaddr.sin_addr;
1512 memcpy(cp + off, &IA_SIN(ia)->sin_addr,
1513 sizeof(struct in_addr));
1514 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1516 * Let ip_intr's mcast routing check handle mcast pkts
1518 forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
1522 if (ipstealth && pass == 0)
1524 if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1525 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1528 if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1529 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1533 * If no space remains, ignore.
1535 off--; /* 0 origin */
1536 if (off > optlen - (int)sizeof(struct in_addr))
1538 memcpy(&ipaddr.sin_addr, &ip->ip_dst,
1539 sizeof ipaddr.sin_addr);
1541 * locate outgoing interface; if we're the destination,
1542 * use the incoming interface (should be same).
1544 if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == NULL &&
1545 (ia = ip_rtaddr(ipaddr.sin_addr, NULL)) == NULL) {
1546 type = ICMP_UNREACH;
1547 code = ICMP_UNREACH_HOST;
1550 memcpy(cp + off, &IA_SIN(ia)->sin_addr,
1551 sizeof(struct in_addr));
1552 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1556 if (ipstealth && pass == 0)
1558 code = cp - (u_char *)ip;
1559 if (optlen < 4 || optlen > 40) {
1560 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1563 if ((off = cp[IPOPT_OFFSET]) < 5) {
1564 code = &cp[IPOPT_OLEN] - (u_char *)ip;
1567 if (off > optlen - (int)sizeof(int32_t)) {
1568 cp[IPOPT_OFFSET + 1] += (1 << 4);
1569 if ((cp[IPOPT_OFFSET + 1] & 0xf0) == 0) {
1570 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1575 off--; /* 0 origin */
1576 sin = (struct in_addr *)(cp + off);
1577 switch (cp[IPOPT_OFFSET + 1] & 0x0f) {
1579 case IPOPT_TS_TSONLY:
1582 case IPOPT_TS_TSANDADDR:
1583 if (off + sizeof(n_time) +
1584 sizeof(struct in_addr) > optlen) {
1585 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1588 ipaddr.sin_addr = dst;
1589 ia = (INA)ifaof_ifpforaddr((SA)&ipaddr,
1593 memcpy(sin, &IA_SIN(ia)->sin_addr,
1594 sizeof(struct in_addr));
1595 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1596 off += sizeof(struct in_addr);
1599 case IPOPT_TS_PRESPEC:
1600 if (off + sizeof(n_time) +
1601 sizeof(struct in_addr) > optlen) {
1602 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1605 memcpy(&ipaddr.sin_addr, sin,
1606 sizeof(struct in_addr));
1607 if (ifa_ifwithaddr((SA)&ipaddr) == NULL)
1609 cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1610 off += sizeof(struct in_addr);
1614 code = &cp[IPOPT_OFFSET + 1] - (u_char *)ip;
1618 memcpy(cp + off, &ntime, sizeof(n_time));
1619 cp[IPOPT_OFFSET] += sizeof(n_time);
1622 if (forward && ipforwarding) {
1623 ip_forward(m, TRUE, next_hop);
1628 icmp_error(m, type, code, 0, 0);
1629 ipstat.ips_badoptions++;
1634 * Given address of next destination (final or next hop),
1635 * return internet address info of interface to be used to get there.
1638 ip_rtaddr(struct in_addr dst, struct route *ro0)
1640 struct route sro, *ro;
1641 struct sockaddr_in *sin;
1642 struct in_ifaddr *ia;
1647 bzero(&sro, sizeof(sro));
1651 sin = (struct sockaddr_in *)&ro->ro_dst;
1653 if (ro->ro_rt == NULL || dst.s_addr != sin->sin_addr.s_addr) {
1654 if (ro->ro_rt != NULL) {
1658 sin->sin_family = AF_INET;
1659 sin->sin_len = sizeof *sin;
1660 sin->sin_addr = dst;
1661 rtalloc_ign(ro, RTF_PRCLONING);
1664 if (ro->ro_rt == NULL)
1667 ia = ifatoia(ro->ro_rt->rt_ifa);
1675 * Save incoming source route for use in replies,
1676 * to be picked up later by ip_srcroute if the receiver is interested.
1679 save_rte(struct mbuf *m, u_char *option, struct in_addr dst)
1682 struct ip_srcrt_opt *opt;
1685 mtag = m_tag_get(PACKET_TAG_IPSRCRT, sizeof(*opt), MB_DONTWAIT);
1688 opt = m_tag_data(mtag);
1690 olen = option[IPOPT_OLEN];
1693 kprintf("save_rte: olen %d\n", olen);
1695 if (olen > sizeof(opt->ip_srcrt) - (1 + sizeof(dst))) {
1699 bcopy(option, opt->ip_srcrt.srcopt, olen);
1700 opt->ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
1701 opt->ip_srcrt.dst = dst;
1702 m_tag_prepend(m, mtag);
1706 * Retrieve incoming source route for use in replies,
1707 * in the same form used by setsockopt.
1708 * The first hop is placed before the options, will be removed later.
1711 ip_srcroute(struct mbuf *m0)
1713 struct in_addr *p, *q;
1716 struct ip_srcrt_opt *opt;
1721 mtag = m_tag_find(m0, PACKET_TAG_IPSRCRT, NULL);
1724 opt = m_tag_data(mtag);
1726 if (opt->ip_nhops == 0)
1728 m = m_get(MB_DONTWAIT, MT_HEADER);
1732 #define OPTSIZ (sizeof(opt->ip_srcrt.nop) + sizeof(opt->ip_srcrt.srcopt))
1734 /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
1735 m->m_len = opt->ip_nhops * sizeof(struct in_addr) +
1736 sizeof(struct in_addr) + OPTSIZ;
1739 kprintf("ip_srcroute: nhops %d mlen %d",
1740 opt->ip_nhops, m->m_len);
1745 * First save first hop for return route
1747 p = &opt->ip_srcrt.route[opt->ip_nhops - 1];
1748 *(mtod(m, struct in_addr *)) = *p--;
1751 kprintf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1755 * Copy option fields and padding (nop) to mbuf.
1757 opt->ip_srcrt.nop = IPOPT_NOP;
1758 opt->ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
1759 memcpy(mtod(m, caddr_t) + sizeof(struct in_addr), &opt->ip_srcrt.nop,
1761 q = (struct in_addr *)(mtod(m, caddr_t) +
1762 sizeof(struct in_addr) + OPTSIZ);
1765 * Record return path as an IP source route,
1766 * reversing the path (pointers are now aligned).
1768 while (p >= opt->ip_srcrt.route) {
1771 kprintf(" %x", ntohl(q->s_addr));
1776 * Last hop goes to final destination.
1778 *q = opt->ip_srcrt.dst;
1779 m_tag_delete(m0, mtag);
1782 kprintf(" %x\n", ntohl(q->s_addr));
1788 * Strip out IP options.
1791 ip_stripoptions(struct mbuf *m)
1794 struct ip *ip = mtod(m, struct ip *);
1798 optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1799 opts = (caddr_t)(ip + 1);
1800 datalen = m->m_len - (sizeof(struct ip) + optlen);
1801 bcopy(opts + optlen, opts, datalen);
1803 if (m->m_flags & M_PKTHDR)
1804 m->m_pkthdr.len -= optlen;
1805 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, sizeof(struct ip) >> 2);
1808 u_char inetctlerrmap[PRC_NCMDS] = {
1810 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1811 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1812 EMSGSIZE, EHOSTUNREACH, 0, 0,
1814 ENOPROTOOPT, ECONNREFUSED
1818 * Forward a packet. If some error occurs return the sender
1819 * an icmp packet. Note we can't always generate a meaningful
1820 * icmp message because icmp doesn't have a large enough repertoire
1821 * of codes and types.
1823 * If not forwarding, just drop the packet. This could be confusing
1824 * if ipforwarding was zero but some routing protocol was advancing
1825 * us as a gateway to somewhere. However, we must let the routing
1826 * protocol deal with that.
1828 * The using_srcrt parameter indicates whether the packet is being forwarded
1829 * via a source route.
1832 ip_forward(struct mbuf *m, boolean_t using_srcrt, struct sockaddr_in *next_hop)
1834 struct ip *ip = mtod(m, struct ip *);
1836 struct route fwd_ro;
1837 int error, type = 0, code = 0, destmtu = 0;
1840 struct in_addr pkt_dst;
1844 * Cache the destination address of the packet; this may be
1845 * changed by use of 'ipfw fwd'.
1847 pkt_dst = (next_hop != NULL) ? next_hop->sin_addr : ip->ip_dst;
1851 kprintf("forward: src %x dst %x ttl %x\n",
1852 ip->ip_src.s_addr, pkt_dst.s_addr, ip->ip_ttl);
1855 if (m->m_flags & (M_BCAST | M_MCAST) || !in_canforward(pkt_dst)) {
1856 ipstat.ips_cantforward++;
1860 if (!ipstealth && ip->ip_ttl <= IPTTLDEC) {
1861 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1865 bzero(&fwd_ro, sizeof(fwd_ro));
1866 ip_rtaddr(pkt_dst, &fwd_ro);
1867 if (fwd_ro.ro_rt == NULL) {
1868 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1874 * Save the IP header and at most 8 bytes of the payload,
1875 * in case we need to generate an ICMP message to the src.
1877 * XXX this can be optimized a lot by saving the data in a local
1878 * buffer on the stack (72 bytes at most), and only allocating the
1879 * mbuf if really necessary. The vast majority of the packets
1880 * are forwarded without having to send an ICMP back (either
1881 * because unnecessary, or because rate limited), so we are
1882 * really we are wasting a lot of work here.
1884 * We don't use m_copy() because it might return a reference
1885 * to a shared cluster. Both this function and ip_output()
1886 * assume exclusive access to the IP header in `m', so any
1887 * data in a cluster may change before we reach icmp_error().
1889 MGETHDR(mcopy, MB_DONTWAIT, m->m_type);
1890 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, MB_DONTWAIT)) {
1892 * It's probably ok if the pkthdr dup fails (because
1893 * the deep copy of the tag chain failed), but for now
1894 * be conservative and just discard the copy since
1895 * code below may some day want the tags.
1900 if (mcopy != NULL) {
1901 mcopy->m_len = imin((IP_VHL_HL(ip->ip_vhl) << 2) + 8,
1903 mcopy->m_pkthdr.len = mcopy->m_len;
1904 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1908 ip->ip_ttl -= IPTTLDEC;
1911 * If forwarding packet using same interface that it came in on,
1912 * perhaps should send a redirect to sender to shortcut a hop.
1913 * Only send redirect if source is sending directly to us,
1914 * and if packet was not source routed (or has any options).
1915 * Also, don't send redirect if forwarding using a default route
1916 * or a route modified by a redirect.
1918 if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1919 !(rt->rt_flags & (RTF_DYNAMIC | RTF_MODIFIED)) &&
1920 satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY &&
1921 ipsendredirects && !using_srcrt && next_hop == NULL) {
1922 u_long src = ntohl(ip->ip_src.s_addr);
1923 struct in_ifaddr *rt_ifa = (struct in_ifaddr *)rt->rt_ifa;
1925 if (rt_ifa != NULL &&
1926 (src & rt_ifa->ia_subnetmask) == rt_ifa->ia_subnet) {
1927 if (rt->rt_flags & RTF_GATEWAY)
1928 dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1930 dest = pkt_dst.s_addr;
1932 * Router requirements says to only send
1935 type = ICMP_REDIRECT;
1936 code = ICMP_REDIRECT_HOST;
1939 kprintf("redirect (%d) to %x\n", code, dest);
1944 error = ip_output(m, NULL, &fwd_ro, IP_FORWARDING, NULL, NULL);
1946 ipstat.ips_forward++;
1949 ipflow_create(&fwd_ro, mcopy);
1954 ipstat.ips_redirectsent++;
1957 ipstat.ips_cantforward++;
1964 * Send ICMP message.
1969 case 0: /* forwarded, but need redirect */
1970 /* type, code set above */
1973 case ENETUNREACH: /* shouldn't happen, checked above */
1978 type = ICMP_UNREACH;
1979 code = ICMP_UNREACH_HOST;
1983 type = ICMP_UNREACH;
1984 code = ICMP_UNREACH_NEEDFRAG;
1987 * If the packet is routed over IPsec tunnel, tell the
1988 * originator the tunnel MTU.
1989 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
1992 if (fwd_ro.ro_rt != NULL) {
1993 struct secpolicy *sp = NULL;
1998 sp = ipsec4_getpolicybyaddr(mcopy,
2004 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu;
2006 /* count IPsec header size */
2007 ipsechdr = ipsec4_hdrsiz(mcopy,
2012 * find the correct route for outer IPv4
2013 * header, compute tunnel MTU.
2016 if (sp->req != NULL && sp->req->sav != NULL &&
2017 sp->req->sav->sah != NULL) {
2018 ro = &sp->req->sav->sah->sa_route;
2019 if (ro->ro_rt != NULL &&
2020 ro->ro_rt->rt_ifp != NULL) {
2022 ro->ro_rt->rt_ifp->if_mtu;
2023 destmtu -= ipsechdr;
2032 * If the packet is routed over IPsec tunnel, tell the
2033 * originator the tunnel MTU.
2034 * tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
2037 if (fwd_ro.ro_rt != NULL) {
2038 struct secpolicy *sp = NULL;
2043 sp = ipsec_getpolicybyaddr(mcopy,
2049 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu;
2051 /* count IPsec header size */
2052 ipsechdr = ipsec4_hdrsiz(mcopy,
2057 * find the correct route for outer IPv4
2058 * header, compute tunnel MTU.
2061 if (sp->req != NULL &&
2062 sp->req->sav != NULL &&
2063 sp->req->sav->sah != NULL) {
2064 ro = &sp->req->sav->sah->sa_route;
2065 if (ro->ro_rt != NULL &&
2066 ro->ro_rt->rt_ifp != NULL) {
2068 ro->ro_rt->rt_ifp->if_mtu;
2069 destmtu -= ipsechdr;
2076 #else /* !IPSEC && !FAST_IPSEC */
2077 if (fwd_ro.ro_rt != NULL)
2078 destmtu = fwd_ro.ro_rt->rt_ifp->if_mtu;
2080 ipstat.ips_cantfrag++;
2085 * A router should not generate ICMP_SOURCEQUENCH as
2086 * required in RFC1812 Requirements for IP Version 4 Routers.
2087 * Source quench could be a big problem under DoS attacks,
2088 * or if the underlying interface is rate-limited.
2089 * Those who need source quench packets may re-enable them
2090 * via the net.inet.ip.sendsourcequench sysctl.
2092 if (!ip_sendsourcequench) {
2096 type = ICMP_SOURCEQUENCH;
2101 case EACCES: /* ipfw denied packet */
2105 icmp_error(mcopy, type, code, dest, destmtu);
2107 if (fwd_ro.ro_rt != NULL)
2108 RTFREE(fwd_ro.ro_rt);
2112 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
2115 if (inp->inp_socket->so_options & SO_TIMESTAMP) {
2119 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
2120 SCM_TIMESTAMP, SOL_SOCKET);
2122 mp = &(*mp)->m_next;
2124 if (inp->inp_flags & INP_RECVDSTADDR) {
2125 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
2126 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
2128 mp = &(*mp)->m_next;
2130 if (inp->inp_flags & INP_RECVTTL) {
2131 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl,
2132 sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
2134 mp = &(*mp)->m_next;
2138 * Moving these out of udp_input() made them even more broken
2139 * than they already were.
2141 /* options were tossed already */
2142 if (inp->inp_flags & INP_RECVOPTS) {
2143 *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
2144 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
2146 mp = &(*mp)->m_next;
2148 /* ip_srcroute doesn't do what we want here, need to fix */
2149 if (inp->inp_flags & INP_RECVRETOPTS) {
2150 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m),
2151 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
2153 mp = &(*mp)->m_next;
2156 if (inp->inp_flags & INP_RECVIF) {
2159 struct sockaddr_dl sdl;
2162 struct sockaddr_dl *sdp;
2163 struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
2165 if (((ifp = m->m_pkthdr.rcvif)) &&
2166 ((ifp->if_index != 0) && (ifp->if_index <= if_index))) {
2167 sdp = IF_LLSOCKADDR(ifp);
2169 * Change our mind and don't try copy.
2171 if ((sdp->sdl_family != AF_LINK) ||
2172 (sdp->sdl_len > sizeof(sdlbuf))) {
2175 bcopy(sdp, sdl2, sdp->sdl_len);
2179 offsetof(struct sockaddr_dl, sdl_data[0]);
2180 sdl2->sdl_family = AF_LINK;
2181 sdl2->sdl_index = 0;
2182 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
2184 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
2185 IP_RECVIF, IPPROTO_IP);
2187 mp = &(*mp)->m_next;
2192 * XXX these routines are called from the upper part of the kernel.
2194 * They could also be moved to ip_mroute.c, since all the RSVP
2195 * handling is done there already.
2198 ip_rsvp_init(struct socket *so)
2200 if (so->so_type != SOCK_RAW ||
2201 so->so_proto->pr_protocol != IPPROTO_RSVP)
2204 if (ip_rsvpd != NULL)
2209 * This may seem silly, but we need to be sure we don't over-increment
2210 * the RSVP counter, in case something slips up.
2225 * This may seem silly, but we need to be sure we don't over-decrement
2226 * the RSVP counter, in case something slips up.
2236 rsvp_input(struct mbuf **mp, int *offp, int proto)
2238 struct mbuf *m = *mp;
2244 if (rsvp_input_p) { /* call the real one if loaded */
2246 rsvp_input_p(mp, offp, proto);
2247 return(IPPROTO_DONE);
2250 /* Can still get packets with rsvp_on = 0 if there is a local member
2251 * of the group to which the RSVP packet is addressed. But in this
2252 * case we want to throw the packet away.
2257 return(IPPROTO_DONE);
2260 if (ip_rsvpd != NULL) {
2262 rip_input(mp, offp, proto);
2263 return(IPPROTO_DONE);
2265 /* Drop the packet */
2267 return(IPPROTO_DONE);