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[dragonfly/port-amd64.git] / sys / netinet / ip_output.c
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1 /*
2 * Copyright (c) 1982, 1986, 1988, 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
29 * @(#)ip_output.c 8.3 (Berkeley) 1/21/94
30 * $FreeBSD: src/sys/netinet/ip_output.c,v 1.99.2.37 2003/04/15 06:44:45 silby Exp $
31 * $DragonFly: src/sys/netinet/ip_output.c,v 1.37 2007/04/04 06:13:26 dillon Exp $
34 #define _IP_VHL
36 #include "opt_ipfw.h"
37 #include "opt_ipdn.h"
38 #include "opt_ipdivert.h"
39 #include "opt_ipfilter.h"
40 #include "opt_ipsec.h"
41 #include "opt_mbuf_stress_test.h"
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 #include <sys/protosw.h>
49 #include <sys/socket.h>
50 #include <sys/socketvar.h>
51 #include <sys/proc.h>
52 #include <sys/sysctl.h>
53 #include <sys/thread2.h>
54 #include <sys/in_cksum.h>
56 #include <net/if.h>
57 #include <net/netisr.h>
58 #include <net/pfil.h>
59 #include <net/route.h>
61 #include <netinet/in.h>
62 #include <netinet/in_systm.h>
63 #include <netinet/ip.h>
64 #include <netinet/in_pcb.h>
65 #include <netinet/in_var.h>
66 #include <netinet/ip_var.h>
68 static MALLOC_DEFINE(M_IPMOPTS, "ip_moptions", "internet multicast options");
70 #ifdef IPSEC
71 #include <netinet6/ipsec.h>
72 #include <netproto/key/key.h>
73 #ifdef IPSEC_DEBUG
74 #include <netproto/key/key_debug.h>
75 #else
76 #define KEYDEBUG(lev,arg)
77 #endif
78 #endif /*IPSEC*/
80 #ifdef FAST_IPSEC
81 #include <netproto/ipsec/ipsec.h>
82 #include <netproto/ipsec/xform.h>
83 #include <netproto/ipsec/key.h>
84 #endif /*FAST_IPSEC*/
86 #include <net/ipfw/ip_fw.h>
87 #include <net/dummynet/ip_dummynet.h>
89 #define print_ip(x, a, y) kprintf("%s %d.%d.%d.%d%s",\
90 x, (ntohl(a.s_addr)>>24)&0xFF,\
91 (ntohl(a.s_addr)>>16)&0xFF,\
92 (ntohl(a.s_addr)>>8)&0xFF,\
93 (ntohl(a.s_addr))&0xFF, y);
95 u_short ip_id;
97 #ifdef MBUF_STRESS_TEST
98 int mbuf_frag_size = 0;
99 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
100 &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
101 #endif
103 static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
104 static struct ifnet *ip_multicast_if(struct in_addr *, int *);
105 static void ip_mloopback
106 (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
107 static int ip_getmoptions
108 (struct sockopt *, struct ip_moptions *);
109 static int ip_pcbopts(int, struct mbuf **, struct mbuf *);
110 static int ip_setmoptions
111 (struct sockopt *, struct ip_moptions **);
113 int ip_optcopy(struct ip *, struct ip *);
116 extern struct protosw inetsw[];
119 * IP output. The packet in mbuf chain m contains a skeletal IP
120 * header (with len, off, ttl, proto, tos, src, dst).
121 * The mbuf chain containing the packet will be freed.
122 * The mbuf opt, if present, will not be freed.
125 ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro,
126 int flags, struct ip_moptions *imo, struct inpcb *inp)
128 struct ip *ip;
129 struct ifnet *ifp = NULL; /* keep compiler happy */
130 struct mbuf *m;
131 int hlen = sizeof(struct ip);
132 int len, off, error = 0;
133 struct sockaddr_in *dst = NULL; /* keep compiler happy */
134 struct in_ifaddr *ia = NULL;
135 int isbroadcast, sw_csum;
136 struct in_addr pkt_dst;
137 struct route iproute;
138 #ifdef IPSEC
139 struct secpolicy *sp = NULL;
140 struct socket *so = inp ? inp->inp_socket : NULL;
141 #endif
142 #ifdef FAST_IPSEC
143 struct m_tag *mtag;
144 struct secpolicy *sp = NULL;
145 struct tdb_ident *tdbi;
146 #endif /* FAST_IPSEC */
147 struct ip_fw_args args;
148 int src_was_INADDR_ANY = 0; /* as the name says... */
150 args.eh = NULL;
151 args.rule = NULL;
152 args.next_hop = NULL;
154 /* Grab info from MT_TAG mbufs prepended to the chain. */
155 while (m0 != NULL && m0->m_type == MT_TAG) {
156 switch(m0->_m_tag_id) {
157 case PACKET_TAG_DUMMYNET:
159 * the packet was already tagged, so part of the
160 * processing was already done, and we need to go down.
161 * Get parameters from the header.
163 args.rule = ((struct dn_pkt *)m0)->rule;
164 opt = NULL ;
165 ro = &((struct dn_pkt *)m0)->ro;
166 imo = NULL ;
167 dst = ((struct dn_pkt *)m0)->dn_dst ;
168 ifp = ((struct dn_pkt *)m0)->ifp ;
169 flags = ((struct dn_pkt *)m0)->flags ;
170 break;
171 case PACKET_TAG_IPFORWARD:
172 args.next_hop = (struct sockaddr_in *)m0->m_data;
173 break;
174 default:
175 kprintf("ip_output: unrecognised MT_TAG tag %d\n",
176 m0->_m_tag_id);
177 break;
179 m0 = m0->m_next;
181 m = m0;
182 KASSERT(m != NULL && (m->m_flags & M_PKTHDR), ("ip_output: no HDR"));
184 if (ro == NULL) {
185 ro = &iproute;
186 bzero(ro, sizeof *ro);
189 if (args.rule != NULL) { /* dummynet already saw us */
190 ip = mtod(m, struct ip *);
191 hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
192 if (ro->ro_rt)
193 ia = ifatoia(ro->ro_rt->rt_ifa);
194 goto sendit;
197 if (opt) {
198 len = 0;
199 m = ip_insertoptions(m, opt, &len);
200 if (len != 0)
201 hlen = len;
203 ip = mtod(m, struct ip *);
204 pkt_dst = args.next_hop ? args.next_hop->sin_addr : ip->ip_dst;
207 * Fill in IP header.
209 if (!(flags & (IP_FORWARDING|IP_RAWOUTPUT))) {
210 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
211 ip->ip_off &= IP_DF;
212 ip->ip_id = ip_newid();
213 ipstat.ips_localout++;
214 } else {
215 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
218 dst = (struct sockaddr_in *)&ro->ro_dst;
220 * If there is a cached route,
221 * check that it is to the same destination
222 * and is still up. If not, free it and try again.
223 * The address family should also be checked in case of sharing the
224 * cache with IPv6.
226 if (ro->ro_rt &&
227 (!(ro->ro_rt->rt_flags & RTF_UP) ||
228 dst->sin_family != AF_INET ||
229 dst->sin_addr.s_addr != pkt_dst.s_addr)) {
230 rtfree(ro->ro_rt);
231 ro->ro_rt = (struct rtentry *)NULL;
233 if (ro->ro_rt == NULL) {
234 bzero(dst, sizeof *dst);
235 dst->sin_family = AF_INET;
236 dst->sin_len = sizeof *dst;
237 dst->sin_addr = pkt_dst;
240 * If routing to interface only,
241 * short circuit routing lookup.
243 if (flags & IP_ROUTETOIF) {
244 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
245 (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
246 ipstat.ips_noroute++;
247 error = ENETUNREACH;
248 goto bad;
250 ifp = ia->ia_ifp;
251 ip->ip_ttl = 1;
252 isbroadcast = in_broadcast(dst->sin_addr, ifp);
253 } else if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) &&
254 imo != NULL && imo->imo_multicast_ifp != NULL) {
256 * Bypass the normal routing lookup for multicast
257 * packets if the interface is specified.
259 ifp = imo->imo_multicast_ifp;
260 IFP_TO_IA(ifp, ia);
261 isbroadcast = 0; /* fool gcc */
262 } else {
264 * If this is the case, we probably don't want to allocate
265 * a protocol-cloned route since we didn't get one from the
266 * ULP. This lets TCP do its thing, while not burdening
267 * forwarding or ICMP with the overhead of cloning a route.
268 * Of course, we still want to do any cloning requested by
269 * the link layer, as this is probably required in all cases
270 * for correct operation (as it is for ARP).
272 if (ro->ro_rt == NULL)
273 rtalloc_ign(ro, RTF_PRCLONING);
274 if (ro->ro_rt == NULL) {
275 ipstat.ips_noroute++;
276 error = EHOSTUNREACH;
277 goto bad;
279 ia = ifatoia(ro->ro_rt->rt_ifa);
280 ifp = ro->ro_rt->rt_ifp;
281 ro->ro_rt->rt_use++;
282 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
283 dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
284 if (ro->ro_rt->rt_flags & RTF_HOST)
285 isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
286 else
287 isbroadcast = in_broadcast(dst->sin_addr, ifp);
289 if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
290 struct in_multi *inm;
292 m->m_flags |= M_MCAST;
294 * IP destination address is multicast. Make sure "dst"
295 * still points to the address in "ro". (It may have been
296 * changed to point to a gateway address, above.)
298 dst = (struct sockaddr_in *)&ro->ro_dst;
300 * See if the caller provided any multicast options
302 if (imo != NULL) {
303 ip->ip_ttl = imo->imo_multicast_ttl;
304 if (imo->imo_multicast_vif != -1)
305 ip->ip_src.s_addr =
306 ip_mcast_src ?
307 ip_mcast_src(imo->imo_multicast_vif) :
308 INADDR_ANY;
309 } else
310 ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
312 * Confirm that the outgoing interface supports multicast.
314 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
315 if (!(ifp->if_flags & IFF_MULTICAST)) {
316 ipstat.ips_noroute++;
317 error = ENETUNREACH;
318 goto bad;
322 * If source address not specified yet, use address
323 * of outgoing interface.
325 if (ip->ip_src.s_addr == INADDR_ANY) {
326 /* Interface may have no addresses. */
327 if (ia != NULL)
328 ip->ip_src = IA_SIN(ia)->sin_addr;
331 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
332 if (inm != NULL &&
333 (imo == NULL || imo->imo_multicast_loop)) {
335 * If we belong to the destination multicast group
336 * on the outgoing interface, and the caller did not
337 * forbid loopback, loop back a copy.
339 ip_mloopback(ifp, m, dst, hlen);
341 else {
343 * If we are acting as a multicast router, perform
344 * multicast forwarding as if the packet had just
345 * arrived on the interface to which we are about
346 * to send. The multicast forwarding function
347 * recursively calls this function, using the
348 * IP_FORWARDING flag to prevent infinite recursion.
350 * Multicasts that are looped back by ip_mloopback(),
351 * above, will be forwarded by the ip_input() routine,
352 * if necessary.
354 if (ip_mrouter && !(flags & IP_FORWARDING)) {
356 * If rsvp daemon is not running, do not
357 * set ip_moptions. This ensures that the packet
358 * is multicast and not just sent down one link
359 * as prescribed by rsvpd.
361 if (!rsvp_on)
362 imo = NULL;
363 if (ip_mforward &&
364 ip_mforward(ip, ifp, m, imo) != 0) {
365 m_freem(m);
366 goto done;
372 * Multicasts with a time-to-live of zero may be looped-
373 * back, above, but must not be transmitted on a network.
374 * Also, multicasts addressed to the loopback interface
375 * are not sent -- the above call to ip_mloopback() will
376 * loop back a copy if this host actually belongs to the
377 * destination group on the loopback interface.
379 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
380 m_freem(m);
381 goto done;
384 goto sendit;
386 #ifndef notdef
388 * If the source address is not specified yet, use the address
389 * of the outoing interface. In case, keep note we did that, so
390 * if the the firewall changes the next-hop causing the output
391 * interface to change, we can fix that.
393 if (ip->ip_src.s_addr == INADDR_ANY) {
394 /* Interface may have no addresses. */
395 if (ia != NULL) {
396 ip->ip_src = IA_SIN(ia)->sin_addr;
397 src_was_INADDR_ANY = 1;
400 #endif /* notdef */
401 #ifdef ALTQ
403 * Disable packet drop hack.
404 * Packetdrop should be done by queueing.
406 #else /* !ALTQ */
408 * Verify that we have any chance at all of being able to queue
409 * the packet or packet fragments
411 if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
412 ifp->if_snd.ifq_maxlen) {
413 error = ENOBUFS;
414 ipstat.ips_odropped++;
415 goto bad;
417 #endif /* !ALTQ */
420 * Look for broadcast address and
421 * verify user is allowed to send
422 * such a packet.
424 if (isbroadcast) {
425 if (!(ifp->if_flags & IFF_BROADCAST)) {
426 error = EADDRNOTAVAIL;
427 goto bad;
429 if (!(flags & IP_ALLOWBROADCAST)) {
430 error = EACCES;
431 goto bad;
433 /* don't allow broadcast messages to be fragmented */
434 if (ip->ip_len > ifp->if_mtu) {
435 error = EMSGSIZE;
436 goto bad;
438 m->m_flags |= M_BCAST;
439 } else {
440 m->m_flags &= ~M_BCAST;
443 sendit:
444 #ifdef IPSEC
445 /* get SP for this packet */
446 if (so == NULL)
447 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
448 else
449 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
451 if (sp == NULL) {
452 ipsecstat.out_inval++;
453 goto bad;
456 error = 0;
458 /* check policy */
459 switch (sp->policy) {
460 case IPSEC_POLICY_DISCARD:
462 * This packet is just discarded.
464 ipsecstat.out_polvio++;
465 goto bad;
467 case IPSEC_POLICY_BYPASS:
468 case IPSEC_POLICY_NONE:
469 /* no need to do IPsec. */
470 goto skip_ipsec;
472 case IPSEC_POLICY_IPSEC:
473 if (sp->req == NULL) {
474 /* acquire a policy */
475 error = key_spdacquire(sp);
476 goto bad;
478 break;
480 case IPSEC_POLICY_ENTRUST:
481 default:
482 kprintf("ip_output: Invalid policy found. %d\n", sp->policy);
485 struct ipsec_output_state state;
486 bzero(&state, sizeof state);
487 state.m = m;
488 if (flags & IP_ROUTETOIF) {
489 state.ro = &iproute;
490 bzero(&iproute, sizeof iproute);
491 } else
492 state.ro = ro;
493 state.dst = (struct sockaddr *)dst;
495 ip->ip_sum = 0;
498 * XXX
499 * delayed checksums are not currently compatible with IPsec
501 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
502 in_delayed_cksum(m);
503 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
506 ip->ip_len = htons(ip->ip_len);
507 ip->ip_off = htons(ip->ip_off);
509 error = ipsec4_output(&state, sp, flags);
511 m = state.m;
512 if (flags & IP_ROUTETOIF) {
514 * if we have tunnel mode SA, we may need to ignore
515 * IP_ROUTETOIF.
517 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
518 flags &= ~IP_ROUTETOIF;
519 ro = state.ro;
521 } else
522 ro = state.ro;
523 dst = (struct sockaddr_in *)state.dst;
524 if (error) {
525 /* mbuf is already reclaimed in ipsec4_output. */
526 m0 = NULL;
527 switch (error) {
528 case EHOSTUNREACH:
529 case ENETUNREACH:
530 case EMSGSIZE:
531 case ENOBUFS:
532 case ENOMEM:
533 break;
534 default:
535 kprintf("ip4_output (ipsec): error code %d\n", error);
536 /*fall through*/
537 case ENOENT:
538 /* don't show these error codes to the user */
539 error = 0;
540 break;
542 goto bad;
546 /* be sure to update variables that are affected by ipsec4_output() */
547 ip = mtod(m, struct ip *);
548 #ifdef _IP_VHL
549 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
550 #else
551 hlen = ip->ip_hl << 2;
552 #endif
553 if (ro->ro_rt == NULL) {
554 if (!(flags & IP_ROUTETOIF)) {
555 kprintf("ip_output: "
556 "can't update route after IPsec processing\n");
557 error = EHOSTUNREACH; /*XXX*/
558 goto bad;
560 } else {
561 ia = ifatoia(ro->ro_rt->rt_ifa);
562 ifp = ro->ro_rt->rt_ifp;
565 /* make it flipped, again. */
566 ip->ip_len = ntohs(ip->ip_len);
567 ip->ip_off = ntohs(ip->ip_off);
568 skip_ipsec:
569 #endif /*IPSEC*/
570 #ifdef FAST_IPSEC
572 * Check the security policy (SP) for the packet and, if
573 * required, do IPsec-related processing. There are two
574 * cases here; the first time a packet is sent through
575 * it will be untagged and handled by ipsec4_checkpolicy.
576 * If the packet is resubmitted to ip_output (e.g. after
577 * AH, ESP, etc. processing), there will be a tag to bypass
578 * the lookup and related policy checking.
580 mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
581 crit_enter();
582 if (mtag != NULL) {
583 tdbi = (struct tdb_ident *)m_tag_data(mtag);
584 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
585 if (sp == NULL)
586 error = -EINVAL; /* force silent drop */
587 m_tag_delete(m, mtag);
588 } else {
589 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
590 &error, inp);
593 * There are four return cases:
594 * sp != NULL apply IPsec policy
595 * sp == NULL, error == 0 no IPsec handling needed
596 * sp == NULL, error == -EINVAL discard packet w/o error
597 * sp == NULL, error != 0 discard packet, report error
599 if (sp != NULL) {
600 /* Loop detection, check if ipsec processing already done */
601 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
602 for (mtag = m_tag_first(m); mtag != NULL;
603 mtag = m_tag_next(m, mtag)) {
604 if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
605 continue;
606 if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
607 mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
608 continue;
610 * Check if policy has an SA associated with it.
611 * This can happen when an SP has yet to acquire
612 * an SA; e.g. on first reference. If it occurs,
613 * then we let ipsec4_process_packet do its thing.
615 if (sp->req->sav == NULL)
616 break;
617 tdbi = (struct tdb_ident *)m_tag_data(mtag);
618 if (tdbi->spi == sp->req->sav->spi &&
619 tdbi->proto == sp->req->sav->sah->saidx.proto &&
620 bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
621 sizeof(union sockaddr_union)) == 0) {
623 * No IPsec processing is needed, free
624 * reference to SP.
626 * NB: null pointer to avoid free at
627 * done: below.
629 KEY_FREESP(&sp), sp = NULL;
630 crit_exit();
631 goto spd_done;
636 * Do delayed checksums now because we send before
637 * this is done in the normal processing path.
639 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
640 in_delayed_cksum(m);
641 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
644 ip->ip_len = htons(ip->ip_len);
645 ip->ip_off = htons(ip->ip_off);
647 /* NB: callee frees mbuf */
648 error = ipsec4_process_packet(m, sp->req, flags, 0);
650 * Preserve KAME behaviour: ENOENT can be returned
651 * when an SA acquire is in progress. Don't propagate
652 * this to user-level; it confuses applications.
654 * XXX this will go away when the SADB is redone.
656 if (error == ENOENT)
657 error = 0;
658 crit_exit();
659 goto done;
660 } else {
661 crit_exit();
663 if (error != 0) {
665 * Hack: -EINVAL is used to signal that a packet
666 * should be silently discarded. This is typically
667 * because we asked key management for an SA and
668 * it was delayed (e.g. kicked up to IKE).
670 if (error == -EINVAL)
671 error = 0;
672 goto bad;
673 } else {
674 /* No IPsec processing for this packet. */
676 #ifdef notyet
678 * If deferred crypto processing is needed, check that
679 * the interface supports it.
681 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
682 if (mtag != NULL && !(ifp->if_capenable & IFCAP_IPSEC)) {
683 /* notify IPsec to do its own crypto */
684 ipsp_skipcrypto_unmark((struct tdb_ident *)m_tag_data(mtag));
685 error = EHOSTUNREACH;
686 goto bad;
688 #endif
690 spd_done:
691 #endif /* FAST_IPSEC */
693 * IpHack's section.
694 * - Xlate: translate packet's addr/port (NAT).
695 * - Firewall: deny/allow/etc.
696 * - Wrap: fake packet's addr/port <unimpl.>
697 * - Encapsulate: put it in another IP and send out. <unimp.>
701 * Run through list of hooks for output packets.
703 if (pfil_has_hooks(&inet_pfil_hook)) {
704 error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
705 if (error != 0 || m == NULL)
706 goto done;
707 ip = mtod(m, struct ip *);
711 * Check with the firewall...
712 * but not if we are already being fwd'd from a firewall.
714 if (fw_enable && IPFW_LOADED && !args.next_hop) {
715 struct sockaddr_in *old = dst;
717 args.m = m;
718 args.next_hop = dst;
719 args.oif = ifp;
720 off = ip_fw_chk_ptr(&args);
721 m = args.m;
722 dst = args.next_hop;
725 * On return we must do the following:
726 * m == NULL -> drop the pkt (old interface, deprecated)
727 * (off & IP_FW_PORT_DENY_FLAG) -> drop the pkt (new interface)
728 * 1<=off<= 0xffff -> DIVERT
729 * (off & IP_FW_PORT_DYNT_FLAG) -> send to a DUMMYNET pipe
730 * (off & IP_FW_PORT_TEE_FLAG) -> TEE the packet
731 * dst != old -> IPFIREWALL_FORWARD
732 * off==0, dst==old -> accept
733 * If some of the above modules are not compiled in, then
734 * we should't have to check the corresponding condition
735 * (because the ipfw control socket should not accept
736 * unsupported rules), but better play safe and drop
737 * packets in case of doubt.
739 if ( (off & IP_FW_PORT_DENY_FLAG) || m == NULL) {
740 if (m)
741 m_freem(m);
742 error = EACCES;
743 goto done;
745 ip = mtod(m, struct ip *);
746 if (off == 0 && dst == old) /* common case */
747 goto pass;
748 if (DUMMYNET_LOADED && (off & IP_FW_PORT_DYNT_FLAG)) {
750 * pass the pkt to dummynet. Need to include
751 * pipe number, m, ifp, ro, dst because these are
752 * not recomputed in the next pass.
753 * All other parameters have been already used and
754 * so they are not needed anymore.
755 * XXX note: if the ifp or ro entry are deleted
756 * while a pkt is in dummynet, we are in trouble!
758 args.ro = ro;
759 args.dst = dst;
760 args.flags = flags;
762 error = ip_dn_io_ptr(m, off & 0xffff, DN_TO_IP_OUT,
763 &args);
764 goto done;
766 #ifdef IPDIVERT
767 if (off != 0 && !(off & IP_FW_PORT_DYNT_FLAG)) {
768 struct mbuf *clone = NULL;
770 /* Clone packet if we're doing a 'tee' */
771 if ((off & IP_FW_PORT_TEE_FLAG))
772 clone = m_dup(m, MB_DONTWAIT);
775 * XXX
776 * delayed checksums are not currently compatible
777 * with divert sockets.
779 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
780 in_delayed_cksum(m);
781 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
784 /* Restore packet header fields to original values */
785 ip->ip_len = htons(ip->ip_len);
786 ip->ip_off = htons(ip->ip_off);
788 /* Deliver packet to divert input routine */
789 divert_packet(m, 0, off & 0xffff);
791 /* If 'tee', continue with original packet */
792 if (clone != NULL) {
793 m = clone;
794 ip = mtod(m, struct ip *);
795 goto pass;
797 goto done;
799 #endif
801 /* IPFIREWALL_FORWARD */
803 * Check dst to make sure it is directly reachable on the
804 * interface we previously thought it was.
805 * If it isn't (which may be likely in some situations) we have
806 * to re-route it (ie, find a route for the next-hop and the
807 * associated interface) and set them here. This is nested
808 * forwarding which in most cases is undesirable, except where
809 * such control is nigh impossible. So we do it here.
810 * And I'm babbling.
812 if (off == 0 && old != dst) { /* FORWARD, dst has changed */
813 #if 0
815 * XXX To improve readability, this block should be
816 * changed into a function call as below:
818 error = ip_ipforward(&m, &dst, &ifp);
819 if (error)
820 goto bad;
821 if (m == NULL) /* ip_input consumed the mbuf */
822 goto done;
823 #else
824 struct in_ifaddr *ia;
827 * XXX sro_fwd below is static, and a pointer
828 * to it gets passed to routines downstream.
829 * This could have surprisingly bad results in
830 * practice, because its content is overwritten
831 * by subsequent packets.
833 /* There must be a better way to do this next line... */
834 static struct route sro_fwd;
835 struct route *ro_fwd = &sro_fwd;
837 #if 0
838 print_ip("IPFIREWALL_FORWARD: New dst ip: ",
839 dst->sin_addr, "\n");
840 #endif
843 * We need to figure out if we have been forwarded
844 * to a local socket. If so, then we should somehow
845 * "loop back" to ip_input, and get directed to the
846 * PCB as if we had received this packet. This is
847 * because it may be dificult to identify the packets
848 * you want to forward until they are being output
849 * and have selected an interface. (e.g. locally
850 * initiated packets) If we used the loopback inteface,
851 * we would not be able to control what happens
852 * as the packet runs through ip_input() as
853 * it is done through a ISR.
855 LIST_FOREACH(ia, INADDR_HASH(dst->sin_addr.s_addr),
856 ia_hash) {
858 * If the addr to forward to is one
859 * of ours, we pretend to
860 * be the destination for this packet.
862 if (IA_SIN(ia)->sin_addr.s_addr ==
863 dst->sin_addr.s_addr)
864 break;
866 if (ia != NULL) { /* tell ip_input "dont filter" */
867 struct m_hdr tag;
869 tag.mh_type = MT_TAG;
870 tag.mh_flags = PACKET_TAG_IPFORWARD;
871 tag.mh_data = (caddr_t)args.next_hop;
872 tag.mh_next = m;
874 if (m->m_pkthdr.rcvif == NULL)
875 m->m_pkthdr.rcvif = ifunit("lo0");
876 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
877 m->m_pkthdr.csum_flags |=
878 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
879 m->m_pkthdr.csum_data = 0xffff;
881 m->m_pkthdr.csum_flags |=
882 CSUM_IP_CHECKED | CSUM_IP_VALID;
883 ip->ip_len = htons(ip->ip_len);
884 ip->ip_off = htons(ip->ip_off);
885 ip_input((struct mbuf *)&tag);
886 goto done;
888 /* Some of the logic for this was nicked from above.
890 * This rewrites the cached route in a local PCB.
891 * Is this what we want to do?
893 bcopy(dst, &ro_fwd->ro_dst, sizeof *dst);
894 ro_fwd->ro_rt = NULL;
896 rtalloc_ign(ro_fwd, RTF_PRCLONING);
897 if (ro_fwd->ro_rt == NULL) {
898 ipstat.ips_noroute++;
899 error = EHOSTUNREACH;
900 goto bad;
903 ia = ifatoia(ro_fwd->ro_rt->rt_ifa);
904 ifp = ro_fwd->ro_rt->rt_ifp;
905 ro_fwd->ro_rt->rt_use++;
906 if (ro_fwd->ro_rt->rt_flags & RTF_GATEWAY)
907 dst = (struct sockaddr_in *)
908 ro_fwd->ro_rt->rt_gateway;
909 if (ro_fwd->ro_rt->rt_flags & RTF_HOST)
910 isbroadcast =
911 (ro_fwd->ro_rt->rt_flags & RTF_BROADCAST);
912 else
913 isbroadcast = in_broadcast(dst->sin_addr, ifp);
914 if (ro->ro_rt != NULL)
915 rtfree(ro->ro_rt);
916 ro->ro_rt = ro_fwd->ro_rt;
917 dst = (struct sockaddr_in *)&ro_fwd->ro_dst;
919 #endif /* ... block to be put into a function */
921 * If we added a default src ip earlier,
922 * which would have been gotten from the-then
923 * interface, do it again, from the new one.
925 if (src_was_INADDR_ANY)
926 ip->ip_src = IA_SIN(ia)->sin_addr;
927 goto pass ;
931 * if we get here, none of the above matches, and
932 * we have to drop the pkt
934 m_freem(m);
935 error = EACCES; /* not sure this is the right error msg */
936 goto done;
939 pass:
940 /* 127/8 must not appear on wire - RFC1122. */
941 if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
942 (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
943 if (!(ifp->if_flags & IFF_LOOPBACK)) {
944 ipstat.ips_badaddr++;
945 error = EADDRNOTAVAIL;
946 goto bad;
950 m->m_pkthdr.csum_flags |= CSUM_IP;
951 sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
952 if (sw_csum & CSUM_DELAY_DATA) {
953 in_delayed_cksum(m);
954 sw_csum &= ~CSUM_DELAY_DATA;
956 m->m_pkthdr.csum_flags &= ifp->if_hwassist;
959 * If small enough for interface, or the interface will take
960 * care of the fragmentation for us, can just send directly.
962 if (ip->ip_len <= ifp->if_mtu || ((ifp->if_hwassist & CSUM_FRAGMENT) &&
963 !(ip->ip_off & IP_DF))) {
964 ip->ip_len = htons(ip->ip_len);
965 ip->ip_off = htons(ip->ip_off);
966 ip->ip_sum = 0;
967 if (sw_csum & CSUM_DELAY_IP) {
968 if (ip->ip_vhl == IP_VHL_BORING) {
969 ip->ip_sum = in_cksum_hdr(ip);
970 } else {
971 ip->ip_sum = in_cksum(m, hlen);
975 /* Record statistics for this interface address. */
976 if (!(flags & IP_FORWARDING) && ia) {
977 ia->ia_ifa.if_opackets++;
978 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
981 #ifdef IPSEC
982 /* clean ipsec history once it goes out of the node */
983 ipsec_delaux(m);
984 #endif
986 #ifdef MBUF_STRESS_TEST
987 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
988 struct mbuf *m1, *m2;
989 int length, tmp;
991 tmp = length = m->m_pkthdr.len;
993 while ((length -= mbuf_frag_size) >= 1) {
994 m1 = m_split(m, length, MB_DONTWAIT);
995 if (m1 == NULL)
996 break;
997 m2 = m;
998 while (m2->m_next != NULL)
999 m2 = m2->m_next;
1000 m2->m_next = m1;
1002 m->m_pkthdr.len = tmp;
1004 #endif
1005 lwkt_serialize_enter(ifp->if_serializer);
1006 error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst,
1007 ro->ro_rt);
1008 lwkt_serialize_exit(ifp->if_serializer);
1009 goto done;
1012 if (ip->ip_off & IP_DF) {
1013 error = EMSGSIZE;
1015 * This case can happen if the user changed the MTU
1016 * of an interface after enabling IP on it. Because
1017 * most netifs don't keep track of routes pointing to
1018 * them, there is no way for one to update all its
1019 * routes when the MTU is changed.
1021 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
1022 !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
1023 (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
1024 ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
1026 ipstat.ips_cantfrag++;
1027 goto bad;
1031 * Too large for interface; fragment if possible. If successful,
1032 * on return, m will point to a list of packets to be sent.
1034 error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
1035 if (error)
1036 goto bad;
1037 for (; m; m = m0) {
1038 m0 = m->m_nextpkt;
1039 m->m_nextpkt = NULL;
1040 #ifdef IPSEC
1041 /* clean ipsec history once it goes out of the node */
1042 ipsec_delaux(m);
1043 #endif
1044 if (error == 0) {
1045 /* Record statistics for this interface address. */
1046 if (ia != NULL) {
1047 ia->ia_ifa.if_opackets++;
1048 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1050 lwkt_serialize_enter(ifp->if_serializer);
1051 error = (*ifp->if_output)(ifp, m,
1052 (struct sockaddr *)dst,
1053 ro->ro_rt);
1054 lwkt_serialize_exit(ifp->if_serializer);
1055 } else {
1056 m_freem(m);
1060 if (error == 0)
1061 ipstat.ips_fragmented++;
1063 done:
1064 if (ro == &iproute && ro->ro_rt != NULL) {
1065 RTFREE(ro->ro_rt);
1066 ro->ro_rt = NULL;
1068 #ifdef IPSEC
1069 if (sp != NULL) {
1070 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1071 kprintf("DP ip_output call free SP:%p\n", sp));
1072 key_freesp(sp);
1074 #endif
1075 #ifdef FAST_IPSEC
1076 if (sp != NULL)
1077 KEY_FREESP(&sp);
1078 #endif
1079 return (error);
1080 bad:
1081 m_freem(m);
1082 goto done;
1086 * Create a chain of fragments which fit the given mtu. m_frag points to the
1087 * mbuf to be fragmented; on return it points to the chain with the fragments.
1088 * Return 0 if no error. If error, m_frag may contain a partially built
1089 * chain of fragments that should be freed by the caller.
1091 * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1092 * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1095 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1096 u_long if_hwassist_flags, int sw_csum)
1098 int error = 0;
1099 int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1100 int len = (mtu - hlen) & ~7; /* size of payload in each fragment */
1101 int off;
1102 struct mbuf *m0 = *m_frag; /* the original packet */
1103 int firstlen;
1104 struct mbuf **mnext;
1105 int nfrags;
1107 if (ip->ip_off & IP_DF) { /* Fragmentation not allowed */
1108 ipstat.ips_cantfrag++;
1109 return EMSGSIZE;
1113 * Must be able to put at least 8 bytes per fragment.
1115 if (len < 8)
1116 return EMSGSIZE;
1119 * If the interface will not calculate checksums on
1120 * fragmented packets, then do it here.
1122 if ((m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) &&
1123 !(if_hwassist_flags & CSUM_IP_FRAGS)) {
1124 in_delayed_cksum(m0);
1125 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1128 if (len > PAGE_SIZE) {
1130 * Fragment large datagrams such that each segment
1131 * contains a multiple of PAGE_SIZE amount of data,
1132 * plus headers. This enables a receiver to perform
1133 * page-flipping zero-copy optimizations.
1135 * XXX When does this help given that sender and receiver
1136 * could have different page sizes, and also mtu could
1137 * be less than the receiver's page size ?
1139 int newlen;
1140 struct mbuf *m;
1142 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1143 off += m->m_len;
1146 * firstlen (off - hlen) must be aligned on an
1147 * 8-byte boundary
1149 if (off < hlen)
1150 goto smart_frag_failure;
1151 off = ((off - hlen) & ~7) + hlen;
1152 newlen = (~PAGE_MASK) & mtu;
1153 if ((newlen + sizeof(struct ip)) > mtu) {
1154 /* we failed, go back the default */
1155 smart_frag_failure:
1156 newlen = len;
1157 off = hlen + len;
1159 len = newlen;
1161 } else {
1162 off = hlen + len;
1165 firstlen = off - hlen;
1166 mnext = &m0->m_nextpkt; /* pointer to next packet */
1169 * Loop through length of segment after first fragment,
1170 * make new header and copy data of each part and link onto chain.
1171 * Here, m0 is the original packet, m is the fragment being created.
1172 * The fragments are linked off the m_nextpkt of the original
1173 * packet, which after processing serves as the first fragment.
1175 for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1176 struct ip *mhip; /* ip header on the fragment */
1177 struct mbuf *m;
1178 int mhlen = sizeof(struct ip);
1180 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1181 if (m == NULL) {
1182 error = ENOBUFS;
1183 ipstat.ips_odropped++;
1184 goto done;
1186 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1188 * In the first mbuf, leave room for the link header, then
1189 * copy the original IP header including options. The payload
1190 * goes into an additional mbuf chain returned by m_copy().
1192 m->m_data += max_linkhdr;
1193 mhip = mtod(m, struct ip *);
1194 *mhip = *ip;
1195 if (hlen > sizeof(struct ip)) {
1196 mhlen = ip_optcopy(ip, mhip) + sizeof(struct ip);
1197 mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1199 m->m_len = mhlen;
1200 /* XXX do we need to add ip->ip_off below ? */
1201 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1202 if (off + len >= ip->ip_len) { /* last fragment */
1203 len = ip->ip_len - off;
1204 m->m_flags |= M_LASTFRAG;
1205 } else
1206 mhip->ip_off |= IP_MF;
1207 mhip->ip_len = htons((u_short)(len + mhlen));
1208 m->m_next = m_copy(m0, off, len);
1209 if (m->m_next == NULL) { /* copy failed */
1210 m_free(m);
1211 error = ENOBUFS; /* ??? */
1212 ipstat.ips_odropped++;
1213 goto done;
1215 m->m_pkthdr.len = mhlen + len;
1216 m->m_pkthdr.rcvif = (struct ifnet *)NULL;
1217 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1218 mhip->ip_off = htons(mhip->ip_off);
1219 mhip->ip_sum = 0;
1220 if (sw_csum & CSUM_DELAY_IP)
1221 mhip->ip_sum = in_cksum(m, mhlen);
1222 *mnext = m;
1223 mnext = &m->m_nextpkt;
1225 ipstat.ips_ofragments += nfrags;
1227 /* set first marker for fragment chain */
1228 m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1229 m0->m_pkthdr.csum_data = nfrags;
1232 * Update first fragment by trimming what's been copied out
1233 * and updating header.
1235 m_adj(m0, hlen + firstlen - ip->ip_len);
1236 m0->m_pkthdr.len = hlen + firstlen;
1237 ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1238 ip->ip_off |= IP_MF;
1239 ip->ip_off = htons(ip->ip_off);
1240 ip->ip_sum = 0;
1241 if (sw_csum & CSUM_DELAY_IP)
1242 ip->ip_sum = in_cksum(m0, hlen);
1244 done:
1245 *m_frag = m0;
1246 return error;
1249 void
1250 in_delayed_cksum(struct mbuf *m)
1252 struct ip *ip;
1253 u_short csum, offset;
1255 ip = mtod(m, struct ip *);
1256 offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1257 csum = in_cksum_skip(m, ip->ip_len, offset);
1258 if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1259 csum = 0xffff;
1260 offset += m->m_pkthdr.csum_data; /* checksum offset */
1262 if (offset + sizeof(u_short) > m->m_len) {
1263 kprintf("delayed m_pullup, m->len: %d off: %d p: %d\n",
1264 m->m_len, offset, ip->ip_p);
1266 * XXX
1267 * this shouldn't happen, but if it does, the
1268 * correct behavior may be to insert the checksum
1269 * in the existing chain instead of rearranging it.
1271 m = m_pullup(m, offset + sizeof(u_short));
1273 *(u_short *)(m->m_data + offset) = csum;
1277 * Insert IP options into preformed packet.
1278 * Adjust IP destination as required for IP source routing,
1279 * as indicated by a non-zero in_addr at the start of the options.
1281 * XXX This routine assumes that the packet has no options in place.
1283 static struct mbuf *
1284 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
1286 struct ipoption *p = mtod(opt, struct ipoption *);
1287 struct mbuf *n;
1288 struct ip *ip = mtod(m, struct ip *);
1289 unsigned optlen;
1291 optlen = opt->m_len - sizeof p->ipopt_dst;
1292 if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1293 *phlen = 0;
1294 return (m); /* XXX should fail */
1296 if (p->ipopt_dst.s_addr)
1297 ip->ip_dst = p->ipopt_dst;
1298 if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1299 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1300 if (n == NULL) {
1301 *phlen = 0;
1302 return (m);
1304 n->m_pkthdr.rcvif = (struct ifnet *)NULL;
1305 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1306 m->m_len -= sizeof(struct ip);
1307 m->m_data += sizeof(struct ip);
1308 n->m_next = m;
1309 m = n;
1310 m->m_len = optlen + sizeof(struct ip);
1311 m->m_data += max_linkhdr;
1312 memcpy(mtod(m, void *), ip, sizeof(struct ip));
1313 } else {
1314 m->m_data -= optlen;
1315 m->m_len += optlen;
1316 m->m_pkthdr.len += optlen;
1317 ovbcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
1319 ip = mtod(m, struct ip *);
1320 bcopy(p->ipopt_list, ip + 1, optlen);
1321 *phlen = sizeof(struct ip) + optlen;
1322 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1323 ip->ip_len += optlen;
1324 return (m);
1328 * Copy options from ip to jp,
1329 * omitting those not copied during fragmentation.
1332 ip_optcopy(struct ip *ip, struct ip *jp)
1334 u_char *cp, *dp;
1335 int opt, optlen, cnt;
1337 cp = (u_char *)(ip + 1);
1338 dp = (u_char *)(jp + 1);
1339 cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1340 for (; cnt > 0; cnt -= optlen, cp += optlen) {
1341 opt = cp[0];
1342 if (opt == IPOPT_EOL)
1343 break;
1344 if (opt == IPOPT_NOP) {
1345 /* Preserve for IP mcast tunnel's LSRR alignment. */
1346 *dp++ = IPOPT_NOP;
1347 optlen = 1;
1348 continue;
1351 KASSERT(cnt >= IPOPT_OLEN + sizeof *cp,
1352 ("ip_optcopy: malformed ipv4 option"));
1353 optlen = cp[IPOPT_OLEN];
1354 KASSERT(optlen >= IPOPT_OLEN + sizeof *cp && optlen <= cnt,
1355 ("ip_optcopy: malformed ipv4 option"));
1357 /* bogus lengths should have been caught by ip_dooptions */
1358 if (optlen > cnt)
1359 optlen = cnt;
1360 if (IPOPT_COPIED(opt)) {
1361 bcopy(cp, dp, optlen);
1362 dp += optlen;
1365 for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1366 *dp++ = IPOPT_EOL;
1367 return (optlen);
1371 * IP socket option processing.
1374 ip_ctloutput(struct socket *so, struct sockopt *sopt)
1376 struct inpcb *inp = so->so_pcb;
1377 int error, optval;
1379 error = optval = 0;
1380 if (sopt->sopt_level != IPPROTO_IP) {
1381 return (EINVAL);
1384 switch (sopt->sopt_dir) {
1385 case SOPT_SET:
1386 switch (sopt->sopt_name) {
1387 case IP_OPTIONS:
1388 #ifdef notyet
1389 case IP_RETOPTS:
1390 #endif
1392 struct mbuf *m;
1393 if (sopt->sopt_valsize > MLEN) {
1394 error = EMSGSIZE;
1395 break;
1397 MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1398 if (m == NULL) {
1399 error = ENOBUFS;
1400 break;
1402 m->m_len = sopt->sopt_valsize;
1403 error = sooptcopyin(sopt, mtod(m, char *), m->m_len,
1404 m->m_len);
1406 return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
1407 m));
1410 case IP_TOS:
1411 case IP_TTL:
1412 case IP_MINTTL:
1413 case IP_RECVOPTS:
1414 case IP_RECVRETOPTS:
1415 case IP_RECVDSTADDR:
1416 case IP_RECVIF:
1417 case IP_RECVTTL:
1418 case IP_FAITH:
1419 error = sooptcopyin(sopt, &optval, sizeof optval,
1420 sizeof optval);
1421 if (error)
1422 break;
1424 switch (sopt->sopt_name) {
1425 case IP_TOS:
1426 inp->inp_ip_tos = optval;
1427 break;
1429 case IP_TTL:
1430 inp->inp_ip_ttl = optval;
1431 break;
1432 case IP_MINTTL:
1433 if (optval > 0 && optval <= MAXTTL)
1434 inp->inp_ip_minttl = optval;
1435 else
1436 error = EINVAL;
1437 break;
1438 #define OPTSET(bit) \
1439 if (optval) \
1440 inp->inp_flags |= bit; \
1441 else \
1442 inp->inp_flags &= ~bit;
1444 case IP_RECVOPTS:
1445 OPTSET(INP_RECVOPTS);
1446 break;
1448 case IP_RECVRETOPTS:
1449 OPTSET(INP_RECVRETOPTS);
1450 break;
1452 case IP_RECVDSTADDR:
1453 OPTSET(INP_RECVDSTADDR);
1454 break;
1456 case IP_RECVIF:
1457 OPTSET(INP_RECVIF);
1458 break;
1460 case IP_RECVTTL:
1461 OPTSET(INP_RECVTTL);
1462 break;
1464 case IP_FAITH:
1465 OPTSET(INP_FAITH);
1466 break;
1468 break;
1469 #undef OPTSET
1471 case IP_MULTICAST_IF:
1472 case IP_MULTICAST_VIF:
1473 case IP_MULTICAST_TTL:
1474 case IP_MULTICAST_LOOP:
1475 case IP_ADD_MEMBERSHIP:
1476 case IP_DROP_MEMBERSHIP:
1477 error = ip_setmoptions(sopt, &inp->inp_moptions);
1478 break;
1480 case IP_PORTRANGE:
1481 error = sooptcopyin(sopt, &optval, sizeof optval,
1482 sizeof optval);
1483 if (error)
1484 break;
1486 switch (optval) {
1487 case IP_PORTRANGE_DEFAULT:
1488 inp->inp_flags &= ~(INP_LOWPORT);
1489 inp->inp_flags &= ~(INP_HIGHPORT);
1490 break;
1492 case IP_PORTRANGE_HIGH:
1493 inp->inp_flags &= ~(INP_LOWPORT);
1494 inp->inp_flags |= INP_HIGHPORT;
1495 break;
1497 case IP_PORTRANGE_LOW:
1498 inp->inp_flags &= ~(INP_HIGHPORT);
1499 inp->inp_flags |= INP_LOWPORT;
1500 break;
1502 default:
1503 error = EINVAL;
1504 break;
1506 break;
1508 #if defined(IPSEC) || defined(FAST_IPSEC)
1509 case IP_IPSEC_POLICY:
1511 caddr_t req;
1512 size_t len = 0;
1513 int priv;
1514 struct mbuf *m;
1515 int optname;
1517 if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1518 break;
1519 if ((error = soopt_mcopyin(sopt, m)) != 0) /* XXX */
1520 break;
1521 priv = (sopt->sopt_td != NULL &&
1522 suser(sopt->sopt_td) != 0) ? 0 : 1;
1523 req = mtod(m, caddr_t);
1524 len = m->m_len;
1525 optname = sopt->sopt_name;
1526 error = ipsec4_set_policy(inp, optname, req, len, priv);
1527 m_freem(m);
1528 break;
1530 #endif /*IPSEC*/
1532 default:
1533 error = ENOPROTOOPT;
1534 break;
1536 break;
1538 case SOPT_GET:
1539 switch (sopt->sopt_name) {
1540 case IP_OPTIONS:
1541 case IP_RETOPTS:
1542 if (inp->inp_options)
1543 error = sooptcopyout(sopt,
1544 mtod(inp->inp_options,
1545 char *),
1546 inp->inp_options->m_len);
1547 else
1548 sopt->sopt_valsize = 0;
1549 break;
1551 case IP_TOS:
1552 case IP_TTL:
1553 case IP_MINTTL:
1554 case IP_RECVOPTS:
1555 case IP_RECVRETOPTS:
1556 case IP_RECVDSTADDR:
1557 case IP_RECVTTL:
1558 case IP_RECVIF:
1559 case IP_PORTRANGE:
1560 case IP_FAITH:
1561 switch (sopt->sopt_name) {
1563 case IP_TOS:
1564 optval = inp->inp_ip_tos;
1565 break;
1567 case IP_TTL:
1568 optval = inp->inp_ip_ttl;
1569 break;
1570 case IP_MINTTL:
1571 optval = inp->inp_ip_minttl;
1572 break;
1574 #define OPTBIT(bit) (inp->inp_flags & bit ? 1 : 0)
1576 case IP_RECVOPTS:
1577 optval = OPTBIT(INP_RECVOPTS);
1578 break;
1580 case IP_RECVRETOPTS:
1581 optval = OPTBIT(INP_RECVRETOPTS);
1582 break;
1584 case IP_RECVDSTADDR:
1585 optval = OPTBIT(INP_RECVDSTADDR);
1586 break;
1588 case IP_RECVTTL:
1589 optval = OPTBIT(INP_RECVTTL);
1590 break;
1592 case IP_RECVIF:
1593 optval = OPTBIT(INP_RECVIF);
1594 break;
1596 case IP_PORTRANGE:
1597 if (inp->inp_flags & INP_HIGHPORT)
1598 optval = IP_PORTRANGE_HIGH;
1599 else if (inp->inp_flags & INP_LOWPORT)
1600 optval = IP_PORTRANGE_LOW;
1601 else
1602 optval = 0;
1603 break;
1605 case IP_FAITH:
1606 optval = OPTBIT(INP_FAITH);
1607 break;
1609 error = sooptcopyout(sopt, &optval, sizeof optval);
1610 break;
1612 case IP_MULTICAST_IF:
1613 case IP_MULTICAST_VIF:
1614 case IP_MULTICAST_TTL:
1615 case IP_MULTICAST_LOOP:
1616 case IP_ADD_MEMBERSHIP:
1617 case IP_DROP_MEMBERSHIP:
1618 error = ip_getmoptions(sopt, inp->inp_moptions);
1619 break;
1621 #if defined(IPSEC) || defined(FAST_IPSEC)
1622 case IP_IPSEC_POLICY:
1624 struct mbuf *m = NULL;
1625 caddr_t req = NULL;
1626 size_t len = 0;
1628 if (m != NULL) {
1629 req = mtod(m, caddr_t);
1630 len = m->m_len;
1632 error = ipsec4_get_policy(so->so_pcb, req, len, &m);
1633 if (error == 0)
1634 error = soopt_mcopyout(sopt, m); /* XXX */
1635 if (error == 0)
1636 m_freem(m);
1637 break;
1639 #endif /*IPSEC*/
1641 default:
1642 error = ENOPROTOOPT;
1643 break;
1645 break;
1647 return (error);
1651 * Set up IP options in pcb for insertion in output packets.
1652 * Store in mbuf with pointer in pcbopt, adding pseudo-option
1653 * with destination address if source routed.
1655 static int
1656 ip_pcbopts(int optname, struct mbuf **pcbopt, struct mbuf *m)
1658 int cnt, optlen;
1659 u_char *cp;
1660 u_char opt;
1662 /* turn off any old options */
1663 if (*pcbopt)
1664 m_free(*pcbopt);
1665 *pcbopt = 0;
1666 if (m == NULL || m->m_len == 0) {
1668 * Only turning off any previous options.
1670 if (m != NULL)
1671 m_free(m);
1672 return (0);
1675 if (m->m_len % sizeof(int32_t))
1676 goto bad;
1678 * IP first-hop destination address will be stored before
1679 * actual options; move other options back
1680 * and clear it when none present.
1682 if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1683 goto bad;
1684 cnt = m->m_len;
1685 m->m_len += sizeof(struct in_addr);
1686 cp = mtod(m, u_char *) + sizeof(struct in_addr);
1687 ovbcopy(mtod(m, caddr_t), cp, cnt);
1688 bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1690 for (; cnt > 0; cnt -= optlen, cp += optlen) {
1691 opt = cp[IPOPT_OPTVAL];
1692 if (opt == IPOPT_EOL)
1693 break;
1694 if (opt == IPOPT_NOP)
1695 optlen = 1;
1696 else {
1697 if (cnt < IPOPT_OLEN + sizeof *cp)
1698 goto bad;
1699 optlen = cp[IPOPT_OLEN];
1700 if (optlen < IPOPT_OLEN + sizeof *cp || optlen > cnt)
1701 goto bad;
1703 switch (opt) {
1705 default:
1706 break;
1708 case IPOPT_LSRR:
1709 case IPOPT_SSRR:
1711 * user process specifies route as:
1712 * ->A->B->C->D
1713 * D must be our final destination (but we can't
1714 * check that since we may not have connected yet).
1715 * A is first hop destination, which doesn't appear in
1716 * actual IP option, but is stored before the options.
1718 if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1719 goto bad;
1720 m->m_len -= sizeof(struct in_addr);
1721 cnt -= sizeof(struct in_addr);
1722 optlen -= sizeof(struct in_addr);
1723 cp[IPOPT_OLEN] = optlen;
1725 * Move first hop before start of options.
1727 bcopy(&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1728 sizeof(struct in_addr));
1730 * Then copy rest of options back
1731 * to close up the deleted entry.
1733 ovbcopy(&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr),
1734 &cp[IPOPT_OFFSET+1],
1735 cnt - (IPOPT_MINOFF - 1));
1736 break;
1739 if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1740 goto bad;
1741 *pcbopt = m;
1742 return (0);
1744 bad:
1745 m_free(m);
1746 return (EINVAL);
1750 * XXX
1751 * The whole multicast option thing needs to be re-thought.
1752 * Several of these options are equally applicable to non-multicast
1753 * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1754 * standard option (IP_TTL).
1758 * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1760 static struct ifnet *
1761 ip_multicast_if(struct in_addr *a, int *ifindexp)
1763 int ifindex;
1764 struct ifnet *ifp;
1766 if (ifindexp)
1767 *ifindexp = 0;
1768 if (ntohl(a->s_addr) >> 24 == 0) {
1769 ifindex = ntohl(a->s_addr) & 0xffffff;
1770 if (ifindex < 0 || if_index < ifindex)
1771 return NULL;
1772 ifp = ifindex2ifnet[ifindex];
1773 if (ifindexp)
1774 *ifindexp = ifindex;
1775 } else {
1776 INADDR_TO_IFP(*a, ifp);
1778 return ifp;
1782 * Set the IP multicast options in response to user setsockopt().
1784 static int
1785 ip_setmoptions(struct sockopt *sopt, struct ip_moptions **imop)
1787 int error = 0;
1788 int i;
1789 struct in_addr addr;
1790 struct ip_mreq mreq;
1791 struct ifnet *ifp;
1792 struct ip_moptions *imo = *imop;
1793 int ifindex;
1795 if (imo == NULL) {
1797 * No multicast option buffer attached to the pcb;
1798 * allocate one and initialize to default values.
1800 imo = kmalloc(sizeof *imo, M_IPMOPTS, M_WAITOK);
1802 if (imo == NULL)
1803 return (ENOBUFS);
1804 *imop = imo;
1805 imo->imo_multicast_ifp = NULL;
1806 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1807 imo->imo_multicast_vif = -1;
1808 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1809 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1810 imo->imo_num_memberships = 0;
1813 switch (sopt->sopt_name) {
1814 /* store an index number for the vif you wanna use in the send */
1815 case IP_MULTICAST_VIF:
1816 if (legal_vif_num == 0) {
1817 error = EOPNOTSUPP;
1818 break;
1820 error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
1821 if (error)
1822 break;
1823 if (!legal_vif_num(i) && (i != -1)) {
1824 error = EINVAL;
1825 break;
1827 imo->imo_multicast_vif = i;
1828 break;
1830 case IP_MULTICAST_IF:
1832 * Select the interface for outgoing multicast packets.
1834 error = sooptcopyin(sopt, &addr, sizeof addr, sizeof addr);
1835 if (error)
1836 break;
1838 * INADDR_ANY is used to remove a previous selection.
1839 * When no interface is selected, a default one is
1840 * chosen every time a multicast packet is sent.
1842 if (addr.s_addr == INADDR_ANY) {
1843 imo->imo_multicast_ifp = NULL;
1844 break;
1847 * The selected interface is identified by its local
1848 * IP address. Find the interface and confirm that
1849 * it supports multicasting.
1851 crit_enter();
1852 ifp = ip_multicast_if(&addr, &ifindex);
1853 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1854 crit_exit();
1855 error = EADDRNOTAVAIL;
1856 break;
1858 imo->imo_multicast_ifp = ifp;
1859 if (ifindex)
1860 imo->imo_multicast_addr = addr;
1861 else
1862 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1863 crit_exit();
1864 break;
1866 case IP_MULTICAST_TTL:
1868 * Set the IP time-to-live for outgoing multicast packets.
1869 * The original multicast API required a char argument,
1870 * which is inconsistent with the rest of the socket API.
1871 * We allow either a char or an int.
1873 if (sopt->sopt_valsize == 1) {
1874 u_char ttl;
1875 error = sooptcopyin(sopt, &ttl, 1, 1);
1876 if (error)
1877 break;
1878 imo->imo_multicast_ttl = ttl;
1879 } else {
1880 u_int ttl;
1881 error = sooptcopyin(sopt, &ttl, sizeof ttl, sizeof ttl);
1882 if (error)
1883 break;
1884 if (ttl > 255)
1885 error = EINVAL;
1886 else
1887 imo->imo_multicast_ttl = ttl;
1889 break;
1891 case IP_MULTICAST_LOOP:
1893 * Set the loopback flag for outgoing multicast packets.
1894 * Must be zero or one. The original multicast API required a
1895 * char argument, which is inconsistent with the rest
1896 * of the socket API. We allow either a char or an int.
1898 if (sopt->sopt_valsize == 1) {
1899 u_char loop;
1901 error = sooptcopyin(sopt, &loop, 1, 1);
1902 if (error)
1903 break;
1904 imo->imo_multicast_loop = !!loop;
1905 } else {
1906 u_int loop;
1908 error = sooptcopyin(sopt, &loop, sizeof loop,
1909 sizeof loop);
1910 if (error)
1911 break;
1912 imo->imo_multicast_loop = !!loop;
1914 break;
1916 case IP_ADD_MEMBERSHIP:
1918 * Add a multicast group membership.
1919 * Group must be a valid IP multicast address.
1921 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
1922 if (error)
1923 break;
1925 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1926 error = EINVAL;
1927 break;
1929 crit_enter();
1931 * If no interface address was provided, use the interface of
1932 * the route to the given multicast address.
1934 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1935 struct sockaddr_in dst;
1936 struct rtentry *rt;
1938 bzero(&dst, sizeof(struct sockaddr_in));
1939 dst.sin_len = sizeof(struct sockaddr_in);
1940 dst.sin_family = AF_INET;
1941 dst.sin_addr = mreq.imr_multiaddr;
1942 rt = rtlookup((struct sockaddr *)&dst);
1943 if (rt == NULL) {
1944 error = EADDRNOTAVAIL;
1945 crit_exit();
1946 break;
1948 --rt->rt_refcnt;
1949 ifp = rt->rt_ifp;
1950 } else {
1951 ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1955 * See if we found an interface, and confirm that it
1956 * supports multicast.
1958 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1959 error = EADDRNOTAVAIL;
1960 crit_exit();
1961 break;
1964 * See if the membership already exists or if all the
1965 * membership slots are full.
1967 for (i = 0; i < imo->imo_num_memberships; ++i) {
1968 if (imo->imo_membership[i]->inm_ifp == ifp &&
1969 imo->imo_membership[i]->inm_addr.s_addr
1970 == mreq.imr_multiaddr.s_addr)
1971 break;
1973 if (i < imo->imo_num_memberships) {
1974 error = EADDRINUSE;
1975 crit_exit();
1976 break;
1978 if (i == IP_MAX_MEMBERSHIPS) {
1979 error = ETOOMANYREFS;
1980 crit_exit();
1981 break;
1984 * Everything looks good; add a new record to the multicast
1985 * address list for the given interface.
1987 if ((imo->imo_membership[i] =
1988 in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1989 error = ENOBUFS;
1990 crit_exit();
1991 break;
1993 ++imo->imo_num_memberships;
1994 crit_exit();
1995 break;
1997 case IP_DROP_MEMBERSHIP:
1999 * Drop a multicast group membership.
2000 * Group must be a valid IP multicast address.
2002 error = sooptcopyin(sopt, &mreq, sizeof mreq, sizeof mreq);
2003 if (error)
2004 break;
2006 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
2007 error = EINVAL;
2008 break;
2011 crit_enter();
2013 * If an interface address was specified, get a pointer
2014 * to its ifnet structure.
2016 if (mreq.imr_interface.s_addr == INADDR_ANY)
2017 ifp = NULL;
2018 else {
2019 ifp = ip_multicast_if(&mreq.imr_interface, NULL);
2020 if (ifp == NULL) {
2021 error = EADDRNOTAVAIL;
2022 crit_exit();
2023 break;
2027 * Find the membership in the membership array.
2029 for (i = 0; i < imo->imo_num_memberships; ++i) {
2030 if ((ifp == NULL ||
2031 imo->imo_membership[i]->inm_ifp == ifp) &&
2032 imo->imo_membership[i]->inm_addr.s_addr ==
2033 mreq.imr_multiaddr.s_addr)
2034 break;
2036 if (i == imo->imo_num_memberships) {
2037 error = EADDRNOTAVAIL;
2038 crit_exit();
2039 break;
2042 * Give up the multicast address record to which the
2043 * membership points.
2045 in_delmulti(imo->imo_membership[i]);
2047 * Remove the gap in the membership array.
2049 for (++i; i < imo->imo_num_memberships; ++i)
2050 imo->imo_membership[i-1] = imo->imo_membership[i];
2051 --imo->imo_num_memberships;
2052 crit_exit();
2053 break;
2055 default:
2056 error = EOPNOTSUPP;
2057 break;
2061 * If all options have default values, no need to keep the mbuf.
2063 if (imo->imo_multicast_ifp == NULL &&
2064 imo->imo_multicast_vif == -1 &&
2065 imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2066 imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2067 imo->imo_num_memberships == 0) {
2068 kfree(*imop, M_IPMOPTS);
2069 *imop = NULL;
2072 return (error);
2076 * Return the IP multicast options in response to user getsockopt().
2078 static int
2079 ip_getmoptions(struct sockopt *sopt, struct ip_moptions *imo)
2081 struct in_addr addr;
2082 struct in_ifaddr *ia;
2083 int error, optval;
2084 u_char coptval;
2086 error = 0;
2087 switch (sopt->sopt_name) {
2088 case IP_MULTICAST_VIF:
2089 if (imo != NULL)
2090 optval = imo->imo_multicast_vif;
2091 else
2092 optval = -1;
2093 error = sooptcopyout(sopt, &optval, sizeof optval);
2094 break;
2096 case IP_MULTICAST_IF:
2097 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2098 addr.s_addr = INADDR_ANY;
2099 else if (imo->imo_multicast_addr.s_addr) {
2100 /* return the value user has set */
2101 addr = imo->imo_multicast_addr;
2102 } else {
2103 IFP_TO_IA(imo->imo_multicast_ifp, ia);
2104 addr.s_addr = (ia == NULL) ? INADDR_ANY
2105 : IA_SIN(ia)->sin_addr.s_addr;
2107 error = sooptcopyout(sopt, &addr, sizeof addr);
2108 break;
2110 case IP_MULTICAST_TTL:
2111 if (imo == NULL)
2112 optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2113 else
2114 optval = coptval = imo->imo_multicast_ttl;
2115 if (sopt->sopt_valsize == 1)
2116 error = sooptcopyout(sopt, &coptval, 1);
2117 else
2118 error = sooptcopyout(sopt, &optval, sizeof optval);
2119 break;
2121 case IP_MULTICAST_LOOP:
2122 if (imo == NULL)
2123 optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2124 else
2125 optval = coptval = imo->imo_multicast_loop;
2126 if (sopt->sopt_valsize == 1)
2127 error = sooptcopyout(sopt, &coptval, 1);
2128 else
2129 error = sooptcopyout(sopt, &optval, sizeof optval);
2130 break;
2132 default:
2133 error = ENOPROTOOPT;
2134 break;
2136 return (error);
2140 * Discard the IP multicast options.
2142 void
2143 ip_freemoptions(struct ip_moptions *imo)
2145 int i;
2147 if (imo != NULL) {
2148 for (i = 0; i < imo->imo_num_memberships; ++i)
2149 in_delmulti(imo->imo_membership[i]);
2150 kfree(imo, M_IPMOPTS);
2155 * Routine called from ip_output() to loop back a copy of an IP multicast
2156 * packet to the input queue of a specified interface. Note that this
2157 * calls the output routine of the loopback "driver", but with an interface
2158 * pointer that might NOT be a loopback interface -- evil, but easier than
2159 * replicating that code here.
2161 static void
2162 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
2163 int hlen)
2165 struct ip *ip;
2166 struct mbuf *copym;
2168 copym = m_copypacket(m, MB_DONTWAIT);
2169 if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2170 copym = m_pullup(copym, hlen);
2171 if (copym != NULL) {
2173 * if the checksum hasn't been computed, mark it as valid
2175 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2176 in_delayed_cksum(copym);
2177 copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2178 copym->m_pkthdr.csum_flags |=
2179 CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2180 copym->m_pkthdr.csum_data = 0xffff;
2183 * We don't bother to fragment if the IP length is greater
2184 * than the interface's MTU. Can this possibly matter?
2186 ip = mtod(copym, struct ip *);
2187 ip->ip_len = htons(ip->ip_len);
2188 ip->ip_off = htons(ip->ip_off);
2189 ip->ip_sum = 0;
2190 if (ip->ip_vhl == IP_VHL_BORING) {
2191 ip->ip_sum = in_cksum_hdr(ip);
2192 } else {
2193 ip->ip_sum = in_cksum(copym, hlen);
2196 * NB:
2197 * It's not clear whether there are any lingering
2198 * reentrancy problems in other areas which might
2199 * be exposed by using ip_input directly (in
2200 * particular, everything which modifies the packet
2201 * in-place). Yet another option is using the
2202 * protosw directly to deliver the looped back
2203 * packet. For the moment, we'll err on the side
2204 * of safety by using if_simloop().
2206 #if 1 /* XXX */
2207 if (dst->sin_family != AF_INET) {
2208 kprintf("ip_mloopback: bad address family %d\n",
2209 dst->sin_family);
2210 dst->sin_family = AF_INET;
2212 #endif
2214 #ifdef notdef
2215 copym->m_pkthdr.rcvif = ifp;
2216 ip_input(copym);
2217 #else
2218 if_simloop(ifp, copym, dst->sin_family, 0);
2219 #endif