2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
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14 * may be used to endorse or promote products derived from this software
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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
33 #include "opt_bootp.h"
35 #include "opt_ipstealth.h"
36 #include "opt_ipsec.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/callout.h>
45 #include <sys/malloc.h>
46 #include <sys/domain.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
50 #include <sys/kernel.h>
51 #include <sys/syslog.h>
52 #include <sys/sysctl.h>
56 #include <net/if_types.h>
57 #include <net/if_var.h>
58 #include <net/if_dl.h>
59 #include <net/route.h>
60 #include <net/netisr.h>
62 #include <netinet/in.h>
63 #include <netinet/in_systm.h>
64 #include <netinet/in_var.h>
65 #include <netinet/ip.h>
66 #include <netinet/in_pcb.h>
67 #include <netinet/ip_var.h>
68 #include <netinet/ip_icmp.h>
69 #include <netinet/ip_options.h>
70 #include <machine/in_cksum.h>
72 #include <netinet/ip_carp.h>
74 #if defined(IPSEC) || defined(FAST_IPSEC)
75 #include <netinet/ip_ipsec.h>
78 #include <sys/socketvar.h>
80 /* XXX: Temporary until ipfw_ether and ipfw_bridge are converted. */
81 #include <netinet/ip_fw.h>
82 #include <netinet/ip_dummynet.h>
87 SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_RW,
88 &ipforwarding, 0, "Enable IP forwarding between interfaces");
90 static int ipsendredirects = 1; /* XXX */
91 SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_RW,
92 &ipsendredirects, 0, "Enable sending IP redirects");
94 int ip_defttl = IPDEFTTL;
95 SYSCTL_INT(_net_inet_ip, IPCTL_DEFTTL, ttl, CTLFLAG_RW,
96 &ip_defttl, 0, "Maximum TTL on IP packets");
98 static int ip_keepfaith = 0;
99 SYSCTL_INT(_net_inet_ip, IPCTL_KEEPFAITH, keepfaith, CTLFLAG_RW,
101 "Enable packet capture for FAITH IPv4->IPv6 translater daemon");
103 static int ip_sendsourcequench = 0;
104 SYSCTL_INT(_net_inet_ip, OID_AUTO, sendsourcequench, CTLFLAG_RW,
105 &ip_sendsourcequench, 0,
106 "Enable the transmission of source quench packets");
108 int ip_do_randomid = 0;
109 SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id, CTLFLAG_RW,
111 "Assign random ip_id values");
114 * XXX - Setting ip_checkinterface mostly implements the receive side of
115 * the Strong ES model described in RFC 1122, but since the routing table
116 * and transmit implementation do not implement the Strong ES model,
117 * setting this to 1 results in an odd hybrid.
119 * XXX - ip_checkinterface currently must be disabled if you use ipnat
120 * to translate the destination address to another local interface.
122 * XXX - ip_checkinterface must be disabled if you add IP aliases
123 * to the loopback interface instead of the interface where the
124 * packets for those addresses are received.
126 static int ip_checkinterface = 0;
127 SYSCTL_INT(_net_inet_ip, OID_AUTO, check_interface, CTLFLAG_RW,
128 &ip_checkinterface, 0, "Verify packet arrives on correct interface");
130 struct pfil_head inet_pfil_hook; /* Packet filter hooks */
132 static struct ifqueue ipintrq;
133 static int ipqmaxlen = IFQ_MAXLEN;
135 extern struct domain inetdomain;
136 extern struct protosw inetsw[];
137 u_char ip_protox[IPPROTO_MAX];
138 struct in_ifaddrhead in_ifaddrhead; /* first inet address */
139 struct in_ifaddrhashhead *in_ifaddrhashtbl; /* inet addr hash table */
140 u_long in_ifaddrhmask; /* mask for hash table */
142 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen, CTLFLAG_RW,
143 &ipintrq.ifq_maxlen, 0, "Maximum size of the IP input queue");
144 SYSCTL_INT(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops, CTLFLAG_RD,
145 &ipintrq.ifq_drops, 0, "Number of packets dropped from the IP input queue");
147 struct ipstat ipstat;
148 SYSCTL_STRUCT(_net_inet_ip, IPCTL_STATS, stats, CTLFLAG_RW,
149 &ipstat, ipstat, "IP statistics (struct ipstat, netinet/ip_var.h)");
152 * IP datagram reassembly.
154 #define IPREASS_NHASH_LOG2 6
155 #define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2)
156 #define IPREASS_HMASK (IPREASS_NHASH - 1)
157 #define IPREASS_HASH(x,y) \
158 (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK)
160 static uma_zone_t ipq_zone;
161 static TAILQ_HEAD(ipqhead, ipq) ipq[IPREASS_NHASH];
162 static struct mtx ipqlock;
164 #define IPQ_LOCK() mtx_lock(&ipqlock)
165 #define IPQ_UNLOCK() mtx_unlock(&ipqlock)
166 #define IPQ_LOCK_INIT() mtx_init(&ipqlock, "ipqlock", NULL, MTX_DEF)
167 #define IPQ_LOCK_ASSERT() mtx_assert(&ipqlock, MA_OWNED)
169 static void maxnipq_update(void);
170 static void ipq_zone_change(void *);
172 static int maxnipq; /* Administrative limit on # reass queues. */
173 static int nipq = 0; /* Total # of reass queues */
174 SYSCTL_INT(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_RD, &nipq, 0,
175 "Current number of IPv4 fragment reassembly queue entries");
177 static int maxfragsperpacket;
178 SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_RW,
179 &maxfragsperpacket, 0,
180 "Maximum number of IPv4 fragments allowed per packet");
182 struct callout ipport_tick_callout;
185 SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
186 &ip_mtu, 0, "Default MTU");
191 SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_RW,
196 * ipfw_ether and ipfw_bridge hooks.
197 * XXX: Temporary until those are converted to pfil_hooks as well.
199 ip_fw_chk_t *ip_fw_chk_ptr = NULL;
200 ip_dn_io_t *ip_dn_io_ptr = NULL;
203 static void ip_freef(struct ipqhead *, struct ipq *);
206 * IP initialization: fill in IP protocol switch table.
207 * All protocols not implemented in kernel go to raw IP protocol handler.
212 register struct protosw *pr;
215 TAILQ_INIT(&in_ifaddrhead);
216 in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &in_ifaddrhmask);
217 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
219 panic("ip_init: PF_INET not found");
221 /* Initialize the entire ip_protox[] array to IPPROTO_RAW. */
222 for (i = 0; i < IPPROTO_MAX; i++)
223 ip_protox[i] = pr - inetsw;
225 * Cycle through IP protocols and put them into the appropriate place
228 for (pr = inetdomain.dom_protosw;
229 pr < inetdomain.dom_protoswNPROTOSW; pr++)
230 if (pr->pr_domain->dom_family == PF_INET &&
231 pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) {
232 /* Be careful to only index valid IP protocols. */
233 if (pr->pr_protocol < IPPROTO_MAX)
234 ip_protox[pr->pr_protocol] = pr - inetsw;
237 /* Initialize packet filter hooks. */
238 inet_pfil_hook.ph_type = PFIL_TYPE_AF;
239 inet_pfil_hook.ph_af = AF_INET;
240 if ((i = pfil_head_register(&inet_pfil_hook)) != 0)
241 printf("%s: WARNING: unable to register pfil hook, "
242 "error %d\n", __func__, i);
244 /* Initialize IP reassembly queue. */
246 for (i = 0; i < IPREASS_NHASH; i++)
248 maxnipq = nmbclusters / 32;
249 maxfragsperpacket = 16;
250 ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL,
251 NULL, UMA_ALIGN_PTR, 0);
254 /* Start ipport_tick. */
255 callout_init(&ipport_tick_callout, CALLOUT_MPSAFE);
257 EVENTHANDLER_REGISTER(shutdown_pre_sync, ip_fini, NULL,
258 SHUTDOWN_PRI_DEFAULT);
259 EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change,
260 NULL, EVENTHANDLER_PRI_ANY);
262 /* Initialize various other remaining things. */
263 ip_id = time_second & 0xffff;
264 ipintrq.ifq_maxlen = ipqmaxlen;
265 mtx_init(&ipintrq.ifq_mtx, "ip_inq", NULL, MTX_DEF);
266 netisr_register(NETISR_IP, ip_input, &ipintrq, NETISR_MPSAFE);
272 callout_stop(&ipport_tick_callout);
276 * Ip input routine. Checksum and byte swap header. If fragmented
277 * try to reassemble. Process options. Pass to next level.
280 ip_input(struct mbuf *m)
282 struct ip *ip = NULL;
283 struct in_ifaddr *ia = NULL;
285 int checkif, hlen = 0;
287 int dchg = 0; /* dest changed after fw */
288 struct in_addr odst; /* original dst address */
292 if (m->m_flags & M_FASTFWD_OURS) {
294 * Firewall or NAT changed destination to local.
295 * We expect ip_len and ip_off to be in host byte order.
297 m->m_flags &= ~M_FASTFWD_OURS;
298 /* Set up some basics that will be used later. */
299 ip = mtod(m, struct ip *);
300 hlen = ip->ip_hl << 2;
306 if (m->m_pkthdr.len < sizeof(struct ip))
309 if (m->m_len < sizeof (struct ip) &&
310 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
311 ipstat.ips_toosmall++;
314 ip = mtod(m, struct ip *);
316 if (ip->ip_v != IPVERSION) {
317 ipstat.ips_badvers++;
321 hlen = ip->ip_hl << 2;
322 if (hlen < sizeof(struct ip)) { /* minimum header length */
323 ipstat.ips_badhlen++;
326 if (hlen > m->m_len) {
327 if ((m = m_pullup(m, hlen)) == NULL) {
328 ipstat.ips_badhlen++;
331 ip = mtod(m, struct ip *);
334 /* 127/8 must not appear on wire - RFC1122 */
335 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
336 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
337 if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
338 ipstat.ips_badaddr++;
343 if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
344 sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
346 if (hlen == sizeof(struct ip)) {
347 sum = in_cksum_hdr(ip);
349 sum = in_cksum(m, hlen);
358 if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0)
359 /* packet is dropped by traffic conditioner */
364 * Convert fields to host representation.
366 ip->ip_len = ntohs(ip->ip_len);
367 if (ip->ip_len < hlen) {
371 ip->ip_off = ntohs(ip->ip_off);
374 * Check that the amount of data in the buffers
375 * is as at least much as the IP header would have us expect.
376 * Trim mbufs if longer than we expect.
377 * Drop packet if shorter than we expect.
379 if (m->m_pkthdr.len < ip->ip_len) {
381 ipstat.ips_tooshort++;
384 if (m->m_pkthdr.len > ip->ip_len) {
385 if (m->m_len == m->m_pkthdr.len) {
386 m->m_len = ip->ip_len;
387 m->m_pkthdr.len = ip->ip_len;
389 m_adj(m, ip->ip_len - m->m_pkthdr.len);
391 #if defined(IPSEC) || defined(FAST_IPSEC)
393 * Bypass packet filtering for packets from a tunnel (gif).
395 if (ip_ipsec_filtergif(m))
400 * Run through list of hooks for input packets.
402 * NB: Beware of the destination address changing (e.g.
403 * by NAT rewriting). When this happens, tell
404 * ip_forward to do the right thing.
407 /* Jump over all PFIL processing if hooks are not active. */
408 if (!PFIL_HOOKED(&inet_pfil_hook))
412 if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif,
415 if (m == NULL) /* consumed by filter */
418 ip = mtod(m, struct ip *);
419 dchg = (odst.s_addr != ip->ip_dst.s_addr);
421 #ifdef IPFIREWALL_FORWARD
422 if (m->m_flags & M_FASTFWD_OURS) {
423 m->m_flags &= ~M_FASTFWD_OURS;
426 #ifndef IPFIREWALL_FORWARD_EXTENDED
427 dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL);
429 if ((dchg = (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL)) != 0) {
431 * Directly ship on the packet. This allows to forward packets
432 * that were destined for us to some other directly connected
438 #endif /* IPFIREWALL_FORWARD_EXTENDED */
439 #endif /* IPFIREWALL_FORWARD */
443 * Process options and, if not destined for us,
444 * ship it on. ip_dooptions returns 1 when an
445 * error was detected (causing an icmp message
446 * to be sent and the original packet to be freed).
448 if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
451 /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
452 * matter if it is destined to another node, or whether it is
453 * a multicast one, RSVP wants it! and prevents it from being forwarded
454 * anywhere else. Also checks if the rsvp daemon is running before
455 * grabbing the packet.
457 if (rsvp_on && ip->ip_p==IPPROTO_RSVP)
461 * Check our list of addresses, to see if the packet is for us.
462 * If we don't have any addresses, assume any unicast packet
463 * we receive might be for us (and let the upper layers deal
466 if (TAILQ_EMPTY(&in_ifaddrhead) &&
467 (m->m_flags & (M_MCAST|M_BCAST)) == 0)
471 * Enable a consistency check between the destination address
472 * and the arrival interface for a unicast packet (the RFC 1122
473 * strong ES model) if IP forwarding is disabled and the packet
474 * is not locally generated and the packet is not subject to
477 * XXX - Checking also should be disabled if the destination
478 * address is ipnat'ed to a different interface.
480 * XXX - Checking is incompatible with IP aliases added
481 * to the loopback interface instead of the interface where
482 * the packets are received.
484 * XXX - This is the case for carp vhost IPs as well so we
485 * insert a workaround. If the packet got here, we already
486 * checked with carp_iamatch() and carp_forus().
488 checkif = ip_checkinterface && (ipforwarding == 0) &&
489 m->m_pkthdr.rcvif != NULL &&
490 ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) &&
492 !m->m_pkthdr.rcvif->if_carp &&
497 * Check for exact addresses in the hash bucket.
499 LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
501 * If the address matches, verify that the packet
502 * arrived via the correct interface if checking is
505 if (IA_SIN(ia)->sin_addr.s_addr == ip->ip_dst.s_addr &&
506 (!checkif || ia->ia_ifp == m->m_pkthdr.rcvif))
510 * Check for broadcast addresses.
512 * Only accept broadcast packets that arrive via the matching
513 * interface. Reception of forwarded directed broadcasts would
514 * be handled via ip_forward() and ether_output() with the loopback
515 * into the stack for SIMPLEX interfaces handled by ether_output().
517 if (m->m_pkthdr.rcvif != NULL &&
518 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
519 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
520 if (ifa->ifa_addr->sa_family != AF_INET)
523 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
526 if (ia->ia_netbroadcast.s_addr == ip->ip_dst.s_addr)
529 if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY)
534 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
535 struct in_multi *inm;
538 * If we are acting as a multicast router, all
539 * incoming multicast packets are passed to the
540 * kernel-level multicast forwarding function.
541 * The packet is returned (relatively) intact; if
542 * ip_mforward() returns a non-zero value, the packet
543 * must be discarded, else it may be accepted below.
546 ip_mforward(ip, m->m_pkthdr.rcvif, m, 0) != 0) {
547 ipstat.ips_cantforward++;
553 * The process-level routing daemon needs to receive
554 * all multicast IGMP packets, whether or not this
555 * host belongs to their destination groups.
557 if (ip->ip_p == IPPROTO_IGMP)
559 ipstat.ips_forward++;
562 * See if we belong to the destination multicast group on the
566 IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
569 ipstat.ips_notmember++;
575 if (ip->ip_dst.s_addr == (u_long)INADDR_BROADCAST)
577 if (ip->ip_dst.s_addr == INADDR_ANY)
581 * FAITH(Firewall Aided Internet Translator)
583 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
585 if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_ICMP)
593 * Not for us; forward if possible and desirable.
595 if (ipforwarding == 0) {
596 ipstat.ips_cantforward++;
599 #if defined(IPSEC) || defined(FAST_IPSEC)
610 * IPSTEALTH: Process non-routing options only
611 * if the packet is destined for us.
613 if (ipstealth && hlen > sizeof (struct ip) &&
616 #endif /* IPSTEALTH */
618 /* Count the packet in the ip address stats */
620 ia->ia_ifa.if_ipackets++;
621 ia->ia_ifa.if_ibytes += m->m_pkthdr.len;
625 * Attempt reassembly; if it succeeds, proceed.
626 * ip_reass() will return a different mbuf.
628 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
632 ip = mtod(m, struct ip *);
633 /* Get the header length of the reassembled packet */
634 hlen = ip->ip_hl << 2;
638 * Further protocols expect the packet length to be w/o the
643 #if defined(IPSEC) || defined(FAST_IPSEC)
645 * enforce IPsec policy checking if we are seeing last header.
646 * note that we do not visit this with protocols with pcb layer
647 * code - like udp/tcp/raw ip.
649 if (ip_ipsec_input(m))
654 * Switch out to protocol's input routine.
656 ipstat.ips_delivered++;
658 (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen);
665 * After maxnipq has been updated, propagate the change to UMA. The UMA zone
666 * max has slightly different semantics than the sysctl, for historical
674 * -1 for unlimited allocation.
677 uma_zone_set_max(ipq_zone, 0);
679 * Positive number for specific bound.
682 uma_zone_set_max(ipq_zone, maxnipq);
684 * Zero specifies no further fragment queue allocation -- set the
685 * bound very low, but rely on implementation elsewhere to actually
686 * prevent allocation and reclaim current queues.
689 uma_zone_set_max(ipq_zone, 1);
693 ipq_zone_change(void *tag)
696 if (maxnipq > 0 && maxnipq < (nmbclusters / 32)) {
697 maxnipq = nmbclusters / 32;
703 sysctl_maxnipq(SYSCTL_HANDLER_ARGS)
708 error = sysctl_handle_int(oidp, &i, 0, req);
709 if (error || !req->newptr)
713 * XXXRW: Might be a good idea to sanity check the argument and place
714 * an extreme upper bound.
723 SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLTYPE_INT|CTLFLAG_RW,
724 NULL, 0, sysctl_maxnipq, "I",
725 "Maximum number of IPv4 fragment reassembly queue entries");
728 * Take incoming datagram fragment and try to reassemble it into
729 * whole datagram. If the argument is the first fragment or one
730 * in between the function will return NULL and store the mbuf
731 * in the fragment chain. If the argument is the last fragment
732 * the packet will be reassembled and the pointer to the new
733 * mbuf returned for further processing. Only m_tags attached
734 * to the first packet/fragment are preserved.
735 * The IP header is *NOT* adjusted out of iplen.
739 ip_reass(struct mbuf *m)
742 struct mbuf *p, *q, *nq, *t;
743 struct ipq *fp = NULL;
744 struct ipqhead *head;
749 /* If maxnipq or maxfragsperpacket are 0, never accept fragments. */
750 if (maxnipq == 0 || maxfragsperpacket == 0) {
751 ipstat.ips_fragments++;
752 ipstat.ips_fragdropped++;
757 ip = mtod(m, struct ip *);
758 hlen = ip->ip_hl << 2;
760 hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id);
765 * Look for queue of fragments
768 TAILQ_FOREACH(fp, head, ipq_list)
769 if (ip->ip_id == fp->ipq_id &&
770 ip->ip_src.s_addr == fp->ipq_src.s_addr &&
771 ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
773 mac_fragment_match(m, fp) &&
775 ip->ip_p == fp->ipq_p)
781 * Attempt to trim the number of allocated fragment queues if it
782 * exceeds the administrative limit.
784 if ((nipq > maxnipq) && (maxnipq > 0)) {
786 * drop something from the tail of the current queue
787 * before proceeding further
789 struct ipq *q = TAILQ_LAST(head, ipqhead);
790 if (q == NULL) { /* gak */
791 for (i = 0; i < IPREASS_NHASH; i++) {
792 struct ipq *r = TAILQ_LAST(&ipq[i], ipqhead);
794 ipstat.ips_fragtimeout += r->ipq_nfrags;
795 ip_freef(&ipq[i], r);
800 ipstat.ips_fragtimeout += q->ipq_nfrags;
807 * Adjust ip_len to not reflect header,
808 * convert offset of this to bytes.
811 if (ip->ip_off & IP_MF) {
813 * Make sure that fragments have a data length
814 * that's a non-zero multiple of 8 bytes.
816 if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) {
817 ipstat.ips_toosmall++; /* XXX */
820 m->m_flags |= M_FRAG;
822 m->m_flags &= ~M_FRAG;
827 * Attempt reassembly; if it succeeds, proceed.
828 * ip_reass() will return a different mbuf.
830 ipstat.ips_fragments++;
831 m->m_pkthdr.header = ip;
833 /* Previous ip_reass() started here. */
835 * Presence of header sizes in mbufs
836 * would confuse code below.
842 * If first fragment to arrive, create a reassembly queue.
845 fp = uma_zalloc(ipq_zone, M_NOWAIT);
849 if (mac_init_ipq(fp, M_NOWAIT) != 0) {
850 uma_zfree(ipq_zone, fp);
854 mac_create_ipq(m, fp);
856 TAILQ_INSERT_HEAD(head, fp, ipq_list);
859 fp->ipq_ttl = IPFRAGTTL;
860 fp->ipq_p = ip->ip_p;
861 fp->ipq_id = ip->ip_id;
862 fp->ipq_src = ip->ip_src;
863 fp->ipq_dst = ip->ip_dst;
870 mac_update_ipq(m, fp);
874 #define GETIP(m) ((struct ip*)((m)->m_pkthdr.header))
877 * Handle ECN by comparing this segment with the first one;
878 * if CE is set, do not lose CE.
879 * drop if CE and not-ECT are mixed for the same packet.
881 ecn = ip->ip_tos & IPTOS_ECN_MASK;
882 ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK;
883 if (ecn == IPTOS_ECN_CE) {
884 if (ecn0 == IPTOS_ECN_NOTECT)
886 if (ecn0 != IPTOS_ECN_CE)
887 GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE;
889 if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT)
893 * Find a segment which begins after this one does.
895 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt)
896 if (GETIP(q)->ip_off > ip->ip_off)
900 * If there is a preceding segment, it may provide some of
901 * our data already. If so, drop the data from the incoming
902 * segment. If it provides all of our data, drop us, otherwise
903 * stick new segment in the proper place.
905 * If some of the data is dropped from the the preceding
906 * segment, then it's checksum is invalidated.
909 i = GETIP(p)->ip_off + GETIP(p)->ip_len - ip->ip_off;
914 m->m_pkthdr.csum_flags = 0;
918 m->m_nextpkt = p->m_nextpkt;
921 m->m_nextpkt = fp->ipq_frags;
926 * While we overlap succeeding segments trim them or,
927 * if they are completely covered, dequeue them.
929 for (; q != NULL && ip->ip_off + ip->ip_len > GETIP(q)->ip_off;
931 i = (ip->ip_off + ip->ip_len) - GETIP(q)->ip_off;
932 if (i < GETIP(q)->ip_len) {
933 GETIP(q)->ip_len -= i;
934 GETIP(q)->ip_off += i;
936 q->m_pkthdr.csum_flags = 0;
941 ipstat.ips_fragdropped++;
947 * Check for complete reassembly and perform frag per packet
950 * Frag limiting is performed here so that the nth frag has
951 * a chance to complete the packet before we drop the packet.
952 * As a result, n+1 frags are actually allowed per packet, but
953 * only n will ever be stored. (n = maxfragsperpacket.)
957 for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) {
958 if (GETIP(q)->ip_off != next) {
959 if (fp->ipq_nfrags > maxfragsperpacket) {
960 ipstat.ips_fragdropped += fp->ipq_nfrags;
965 next += GETIP(q)->ip_len;
967 /* Make sure the last packet didn't have the IP_MF flag */
968 if (p->m_flags & M_FRAG) {
969 if (fp->ipq_nfrags > maxfragsperpacket) {
970 ipstat.ips_fragdropped += fp->ipq_nfrags;
977 * Reassembly is complete. Make sure the packet is a sane size.
981 if (next + (ip->ip_hl << 2) > IP_MAXPACKET) {
982 ipstat.ips_toolong++;
983 ipstat.ips_fragdropped += fp->ipq_nfrags;
989 * Concatenate fragments.
997 for (q = nq; q != NULL; q = nq) {
1000 m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags;
1001 m->m_pkthdr.csum_data += q->m_pkthdr.csum_data;
1005 * In order to do checksumming faster we do 'end-around carry' here
1006 * (and not in for{} loop), though it implies we are not going to
1007 * reassemble more than 64k fragments.
1009 m->m_pkthdr.csum_data =
1010 (m->m_pkthdr.csum_data & 0xffff) + (m->m_pkthdr.csum_data >> 16);
1012 mac_create_datagram_from_ipq(fp, m);
1013 mac_destroy_ipq(fp);
1017 * Create header for new ip packet by modifying header of first
1018 * packet; dequeue and discard fragment reassembly header.
1019 * Make header visible.
1021 ip->ip_len = (ip->ip_hl << 2) + next;
1022 ip->ip_src = fp->ipq_src;
1023 ip->ip_dst = fp->ipq_dst;
1024 TAILQ_REMOVE(head, fp, ipq_list);
1026 uma_zfree(ipq_zone, fp);
1027 m->m_len += (ip->ip_hl << 2);
1028 m->m_data -= (ip->ip_hl << 2);
1029 /* some debugging cruft by sklower, below, will go away soon */
1030 if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */
1032 ipstat.ips_reassembled++;
1037 ipstat.ips_fragdropped++;
1049 * Free a fragment reassembly header and all
1050 * associated datagrams.
1054 struct ipqhead *fhp;
1057 register struct mbuf *q;
1061 while (fp->ipq_frags) {
1063 fp->ipq_frags = q->m_nextpkt;
1066 TAILQ_REMOVE(fhp, fp, ipq_list);
1067 uma_zfree(ipq_zone, fp);
1072 * IP timer processing;
1073 * if a timer expires on a reassembly
1074 * queue, discard it.
1079 register struct ipq *fp;
1083 for (i = 0; i < IPREASS_NHASH; i++) {
1084 for(fp = TAILQ_FIRST(&ipq[i]); fp;) {
1088 fp = TAILQ_NEXT(fp, ipq_list);
1089 if(--fpp->ipq_ttl == 0) {
1090 ipstat.ips_fragtimeout += fpp->ipq_nfrags;
1091 ip_freef(&ipq[i], fpp);
1096 * If we are over the maximum number of fragments
1097 * (due to the limit being lowered), drain off
1098 * enough to get down to the new limit.
1100 if (maxnipq >= 0 && nipq > maxnipq) {
1101 for (i = 0; i < IPREASS_NHASH; i++) {
1102 while (nipq > maxnipq && !TAILQ_EMPTY(&ipq[i])) {
1103 ipstat.ips_fragdropped +=
1104 TAILQ_FIRST(&ipq[i])->ipq_nfrags;
1105 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
1113 * Drain off all datagram fragments.
1121 for (i = 0; i < IPREASS_NHASH; i++) {
1122 while(!TAILQ_EMPTY(&ipq[i])) {
1123 ipstat.ips_fragdropped +=
1124 TAILQ_FIRST(&ipq[i])->ipq_nfrags;
1125 ip_freef(&ipq[i], TAILQ_FIRST(&ipq[i]));
1133 * The protocol to be inserted into ip_protox[] must be already registered
1134 * in inetsw[], either statically or through pf_proto_register().
1137 ipproto_register(u_char ipproto)
1141 /* Sanity checks. */
1143 return (EPROTONOSUPPORT);
1146 * The protocol slot must not be occupied by another protocol
1147 * already. An index pointing to IPPROTO_RAW is unused.
1149 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1151 return (EPFNOSUPPORT);
1152 if (ip_protox[ipproto] != pr - inetsw) /* IPPROTO_RAW */
1155 /* Find the protocol position in inetsw[] and set the index. */
1156 for (pr = inetdomain.dom_protosw;
1157 pr < inetdomain.dom_protoswNPROTOSW; pr++) {
1158 if (pr->pr_domain->dom_family == PF_INET &&
1159 pr->pr_protocol && pr->pr_protocol == ipproto) {
1160 /* Be careful to only index valid IP protocols. */
1161 if (pr->pr_protocol < IPPROTO_MAX) {
1162 ip_protox[pr->pr_protocol] = pr - inetsw;
1168 return (EPROTONOSUPPORT);
1172 ipproto_unregister(u_char ipproto)
1176 /* Sanity checks. */
1178 return (EPROTONOSUPPORT);
1180 /* Check if the protocol was indeed registered. */
1181 pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
1183 return (EPFNOSUPPORT);
1184 if (ip_protox[ipproto] == pr - inetsw) /* IPPROTO_RAW */
1187 /* Reset the protocol slot to IPPROTO_RAW. */
1188 ip_protox[ipproto] = pr - inetsw;
1193 * Given address of next destination (final or next hop),
1194 * return internet address info of interface to be used to get there.
1201 struct sockaddr_in *sin;
1202 struct in_ifaddr *ifa;
1204 bzero(&sro, sizeof(sro));
1205 sin = (struct sockaddr_in *)&sro.ro_dst;
1206 sin->sin_family = AF_INET;
1207 sin->sin_len = sizeof(*sin);
1208 sin->sin_addr = dst;
1209 rtalloc_ign(&sro, RTF_CLONING);
1211 if (sro.ro_rt == NULL)
1214 ifa = ifatoia(sro.ro_rt->rt_ifa);
1219 u_char inetctlerrmap[PRC_NCMDS] = {
1221 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
1222 EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
1223 EMSGSIZE, EHOSTUNREACH, 0, 0,
1224 0, 0, EHOSTUNREACH, 0,
1225 ENOPROTOOPT, ECONNREFUSED
1229 * Forward a packet. If some error occurs return the sender
1230 * an icmp packet. Note we can't always generate a meaningful
1231 * icmp message because icmp doesn't have a large enough repertoire
1232 * of codes and types.
1234 * If not forwarding, just drop the packet. This could be confusing
1235 * if ipforwarding was zero but some routing protocol was advancing
1236 * us as a gateway to somewhere. However, we must let the routing
1237 * protocol deal with that.
1239 * The srcrt parameter indicates whether the packet is being forwarded
1240 * via a source route.
1243 ip_forward(struct mbuf *m, int srcrt)
1245 struct ip *ip = mtod(m, struct ip *);
1246 struct in_ifaddr *ia = NULL;
1248 struct in_addr dest;
1249 int error, type = 0, code = 0, mtu = 0;
1251 if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1252 ipstat.ips_cantforward++;
1259 if (ip->ip_ttl <= IPTTLDEC) {
1260 icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
1268 if (!srcrt && (ia = ip_rtaddr(ip->ip_dst)) == NULL) {
1269 icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
1274 * Save the IP header and at most 8 bytes of the payload,
1275 * in case we need to generate an ICMP message to the src.
1277 * XXX this can be optimized a lot by saving the data in a local
1278 * buffer on the stack (72 bytes at most), and only allocating the
1279 * mbuf if really necessary. The vast majority of the packets
1280 * are forwarded without having to send an ICMP back (either
1281 * because unnecessary, or because rate limited), so we are
1282 * really we are wasting a lot of work here.
1284 * We don't use m_copy() because it might return a reference
1285 * to a shared cluster. Both this function and ip_output()
1286 * assume exclusive access to the IP header in `m', so any
1287 * data in a cluster may change before we reach icmp_error().
1289 MGETHDR(mcopy, M_DONTWAIT, m->m_type);
1290 if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_DONTWAIT)) {
1292 * It's probably ok if the pkthdr dup fails (because
1293 * the deep copy of the tag chain failed), but for now
1294 * be conservative and just discard the copy since
1295 * code below may some day want the tags.
1300 if (mcopy != NULL) {
1301 mcopy->m_len = min(ip->ip_len, M_TRAILINGSPACE(mcopy));
1302 mcopy->m_pkthdr.len = mcopy->m_len;
1303 m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
1309 ip->ip_ttl -= IPTTLDEC;
1315 * If forwarding packet using same interface that it came in on,
1316 * perhaps should send a redirect to sender to shortcut a hop.
1317 * Only send redirect if source is sending directly to us,
1318 * and if packet was not source routed (or has any options).
1319 * Also, don't send redirect if forwarding using a default route
1320 * or a route modified by a redirect.
1323 if (!srcrt && ipsendredirects && ia->ia_ifp == m->m_pkthdr.rcvif) {
1324 struct sockaddr_in *sin;
1328 bzero(&ro, sizeof(ro));
1329 sin = (struct sockaddr_in *)&ro.ro_dst;
1330 sin->sin_family = AF_INET;
1331 sin->sin_len = sizeof(*sin);
1332 sin->sin_addr = ip->ip_dst;
1333 rtalloc_ign(&ro, RTF_CLONING);
1337 if (rt && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1338 satosin(rt_key(rt))->sin_addr.s_addr != 0) {
1339 #define RTA(rt) ((struct in_ifaddr *)(rt->rt_ifa))
1340 u_long src = ntohl(ip->ip_src.s_addr);
1343 (src & RTA(rt)->ia_subnetmask) == RTA(rt)->ia_subnet) {
1344 if (rt->rt_flags & RTF_GATEWAY)
1345 dest.s_addr = satosin(rt->rt_gateway)->sin_addr.s_addr;
1347 dest.s_addr = ip->ip_dst.s_addr;
1348 /* Router requirements says to only send host redirects */
1349 type = ICMP_REDIRECT;
1350 code = ICMP_REDIRECT_HOST;
1357 error = ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
1359 ipstat.ips_cantforward++;
1361 ipstat.ips_forward++;
1363 ipstat.ips_redirectsent++;
1375 case 0: /* forwarded, but need redirect */
1376 /* type, code set above */
1379 case ENETUNREACH: /* shouldn't happen, checked above */
1384 type = ICMP_UNREACH;
1385 code = ICMP_UNREACH_HOST;
1389 type = ICMP_UNREACH;
1390 code = ICMP_UNREACH_NEEDFRAG;
1392 #if defined(IPSEC) || defined(FAST_IPSEC)
1393 mtu = ip_ipsec_mtu(m);
1396 * If the MTU wasn't set before use the interface mtu or
1397 * fall back to the next smaller mtu step compared to the
1398 * current packet size.
1402 mtu = ia->ia_ifp->if_mtu;
1404 mtu = ip_next_mtu(ip->ip_len, 0);
1406 ipstat.ips_cantfrag++;
1411 * A router should not generate ICMP_SOURCEQUENCH as
1412 * required in RFC1812 Requirements for IP Version 4 Routers.
1413 * Source quench could be a big problem under DoS attacks,
1414 * or if the underlying interface is rate-limited.
1415 * Those who need source quench packets may re-enable them
1416 * via the net.inet.ip.sendsourcequench sysctl.
1418 if (ip_sendsourcequench == 0) {
1422 type = ICMP_SOURCEQUENCH;
1427 case EACCES: /* ipfw denied packet */
1431 icmp_error(mcopy, type, code, dest.s_addr, mtu);
1435 ip_savecontrol(inp, mp, ip, m)
1436 register struct inpcb *inp;
1437 register struct mbuf **mp;
1438 register struct ip *ip;
1439 register struct mbuf *m;
1441 if (inp->inp_socket->so_options & (SO_BINTIME | SO_TIMESTAMP)) {
1445 if (inp->inp_socket->so_options & SO_BINTIME) {
1446 *mp = sbcreatecontrol((caddr_t) &bt, sizeof(bt),
1447 SCM_BINTIME, SOL_SOCKET);
1449 mp = &(*mp)->m_next;
1451 if (inp->inp_socket->so_options & SO_TIMESTAMP) {
1454 bintime2timeval(&bt, &tv);
1455 *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1456 SCM_TIMESTAMP, SOL_SOCKET);
1458 mp = &(*mp)->m_next;
1461 if (inp->inp_flags & INP_RECVDSTADDR) {
1462 *mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
1463 sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1465 mp = &(*mp)->m_next;
1467 if (inp->inp_flags & INP_RECVTTL) {
1468 *mp = sbcreatecontrol((caddr_t) &ip->ip_ttl,
1469 sizeof(u_char), IP_RECVTTL, IPPROTO_IP);
1471 mp = &(*mp)->m_next;
1475 * Moving these out of udp_input() made them even more broken
1476 * than they already were.
1478 /* options were tossed already */
1479 if (inp->inp_flags & INP_RECVOPTS) {
1480 *mp = sbcreatecontrol((caddr_t) opts_deleted_above,
1481 sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
1483 mp = &(*mp)->m_next;
1485 /* ip_srcroute doesn't do what we want here, need to fix */
1486 if (inp->inp_flags & INP_RECVRETOPTS) {
1487 *mp = sbcreatecontrol((caddr_t) ip_srcroute(m),
1488 sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
1490 mp = &(*mp)->m_next;
1493 if (inp->inp_flags & INP_RECVIF) {
1496 struct sockaddr_dl sdl;
1499 struct sockaddr_dl *sdp;
1500 struct sockaddr_dl *sdl2 = &sdlbuf.sdl;
1502 if (((ifp = m->m_pkthdr.rcvif))
1503 && ( ifp->if_index && (ifp->if_index <= if_index))) {
1504 sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
1506 * Change our mind and don't try copy.
1508 if ((sdp->sdl_family != AF_LINK)
1509 || (sdp->sdl_len > sizeof(sdlbuf))) {
1512 bcopy(sdp, sdl2, sdp->sdl_len);
1516 = offsetof(struct sockaddr_dl, sdl_data[0]);
1517 sdl2->sdl_family = AF_LINK;
1518 sdl2->sdl_index = 0;
1519 sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
1521 *mp = sbcreatecontrol((caddr_t) sdl2, sdl2->sdl_len,
1522 IP_RECVIF, IPPROTO_IP);
1524 mp = &(*mp)->m_next;
1529 * XXX these routines are called from the upper part of the kernel.
1530 * They need to be locked when we remove Giant.
1532 * They could also be moved to ip_mroute.c, since all the RSVP
1533 * handling is done there already.
1535 static int ip_rsvp_on;
1536 struct socket *ip_rsvpd;
1538 ip_rsvp_init(struct socket *so)
1540 if (so->so_type != SOCK_RAW ||
1541 so->so_proto->pr_protocol != IPPROTO_RSVP)
1544 if (ip_rsvpd != NULL)
1549 * This may seem silly, but we need to be sure we don't over-increment
1550 * the RSVP counter, in case something slips up.
1565 * This may seem silly, but we need to be sure we don't over-decrement
1566 * the RSVP counter, in case something slips up.
1576 rsvp_input(struct mbuf *m, int off) /* XXX must fixup manually */
1578 if (rsvp_input_p) { /* call the real one if loaded */
1579 rsvp_input_p(m, off);
1583 /* Can still get packets with rsvp_on = 0 if there is a local member
1584 * of the group to which the RSVP packet is addressed. But in this
1585 * case we want to throw the packet away.
1593 if (ip_rsvpd != NULL) {
1597 /* Drop the packet */