Replace all casts of NULL to something with NULL.
[dragonfly.git] / sys / netinet / ip_output.c
1 /*
2  * Copyright (c) 1982, 1986, 1988, 1990, 1993
3  *      The Regents of the University of California.  All rights reserved.
4  *
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.
16  *
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.
28  *
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 1.67 2008/10/28 03:07:28 sephe Exp $
32  */
33
34 #define _IP_VHL
35
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"
42 #include "opt_mpls.h"
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/malloc.h>
48 #include <sys/mbuf.h>
49 #include <sys/protosw.h>
50 #include <sys/socket.h>
51 #include <sys/socketvar.h>
52 #include <sys/proc.h>
53 #include <sys/priv.h>
54 #include <sys/sysctl.h>
55 #include <sys/thread2.h>
56 #include <sys/in_cksum.h>
57 #include <sys/lock.h>
58
59 #include <net/if.h>
60 #include <net/netisr.h>
61 #include <net/pfil.h>
62 #include <net/route.h>
63
64 #include <netinet/in.h>
65 #include <netinet/in_systm.h>
66 #include <netinet/ip.h>
67 #include <netinet/in_pcb.h>
68 #include <netinet/in_var.h>
69 #include <netinet/ip_var.h>
70
71 #include <netproto/mpls/mpls_var.h>
72
73 static MALLOC_DEFINE(M_IPMOPTS, "ip_moptions", "internet multicast options");
74
75 #ifdef IPSEC
76 #include <netinet6/ipsec.h>
77 #include <netproto/key/key.h>
78 #ifdef IPSEC_DEBUG
79 #include <netproto/key/key_debug.h>
80 #else
81 #define KEYDEBUG(lev,arg)
82 #endif
83 #endif /*IPSEC*/
84
85 #ifdef FAST_IPSEC
86 #include <netproto/ipsec/ipsec.h>
87 #include <netproto/ipsec/xform.h>
88 #include <netproto/ipsec/key.h>
89 #endif /*FAST_IPSEC*/
90
91 #include <net/ipfw/ip_fw.h>
92 #include <net/dummynet/ip_dummynet.h>
93
94 #define print_ip(x, a, y)        kprintf("%s %d.%d.%d.%d%s",\
95                                 x, (ntohl(a.s_addr)>>24)&0xFF,\
96                                   (ntohl(a.s_addr)>>16)&0xFF,\
97                                   (ntohl(a.s_addr)>>8)&0xFF,\
98                                   (ntohl(a.s_addr))&0xFF, y);
99
100 u_short ip_id;
101
102 #ifdef MBUF_STRESS_TEST
103 int mbuf_frag_size = 0;
104 SYSCTL_INT(_net_inet_ip, OID_AUTO, mbuf_frag_size, CTLFLAG_RW,
105         &mbuf_frag_size, 0, "Fragment outgoing mbufs to this size");
106 #endif
107
108 static struct mbuf *ip_insertoptions(struct mbuf *, struct mbuf *, int *);
109 static struct ifnet *ip_multicast_if(struct in_addr *, int *);
110 static void     ip_mloopback
111         (struct ifnet *, struct mbuf *, struct sockaddr_in *, int);
112 static int      ip_getmoptions
113         (struct sockopt *, struct ip_moptions *);
114 static int      ip_pcbopts(int, struct mbuf **, struct mbuf *);
115 static int      ip_setmoptions
116         (struct sockopt *, struct ip_moptions **);
117
118 int     ip_optcopy(struct ip *, struct ip *);
119
120 extern  int route_assert_owner_access;
121
122 extern  struct protosw inetsw[];
123
124 static int
125 ip_localforward(struct mbuf *m, const struct sockaddr_in *dst, int hlen)
126 {
127         struct in_ifaddr_container *iac;
128
129         /*
130          * We need to figure out if we have been forwarded to a local
131          * socket.  If so, then we should somehow "loop back" to
132          * ip_input(), and get directed to the PCB as if we had received
133          * this packet.  This is because it may be difficult to identify
134          * the packets you want to forward until they are being output
135          * and have selected an interface (e.g. locally initiated
136          * packets).  If we used the loopback inteface, we would not be
137          * able to control what happens as the packet runs through
138          * ip_input() as it is done through a ISR.
139          */
140         LIST_FOREACH(iac, INADDR_HASH(dst->sin_addr.s_addr), ia_hash) {
141                 /*
142                  * If the addr to forward to is one of ours, we pretend
143                  * to be the destination for this packet.
144                  */
145                 if (IA_SIN(iac->ia)->sin_addr.s_addr == dst->sin_addr.s_addr)
146                         break;
147         }
148         if (iac != NULL) {
149                 struct ip *ip;
150
151                 if (m->m_pkthdr.rcvif == NULL)
152                         m->m_pkthdr.rcvif = ifunit("lo0");
153                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
154                         m->m_pkthdr.csum_flags |= CSUM_DATA_VALID |
155                                                   CSUM_PSEUDO_HDR;
156                         m->m_pkthdr.csum_data = 0xffff;
157                 }
158                 m->m_pkthdr.csum_flags |= CSUM_IP_CHECKED | CSUM_IP_VALID;
159
160                 /*
161                  * Make sure that the IP header is in one mbuf,
162                  * required by ip_input
163                  */
164                 if (m->m_len < hlen) {
165                         m = m_pullup(m, hlen);
166                         if (m == NULL) {
167                                 /* The packet was freed; we are done */
168                                 return 1;
169                         }
170                 }
171                 ip = mtod(m, struct ip *);
172
173                 ip->ip_len = htons(ip->ip_len);
174                 ip->ip_off = htons(ip->ip_off);
175                 ip_input(m);
176
177                 return 1; /* The packet gets forwarded locally */
178         }
179         return 0;
180 }
181
182 /*
183  * IP output.  The packet in mbuf chain m contains a skeletal IP
184  * header (with len, off, ttl, proto, tos, src, dst).
185  * The mbuf chain containing the packet will be freed.
186  * The mbuf opt, if present, will not be freed.
187  */
188 int
189 ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro,
190           int flags, struct ip_moptions *imo, struct inpcb *inp)
191 {
192         struct ip *ip;
193         struct ifnet *ifp = NULL;       /* keep compiler happy */
194         struct mbuf *m;
195         int hlen = sizeof(struct ip);
196         int len, error = 0;
197         struct sockaddr_in *dst = NULL; /* keep compiler happy */
198         struct in_ifaddr *ia = NULL;
199         int isbroadcast, sw_csum;
200         struct in_addr pkt_dst;
201         struct route iproute;
202         struct m_tag *mtag;
203 #ifdef IPSEC
204         struct secpolicy *sp = NULL;
205         struct socket *so = inp ? inp->inp_socket : NULL;
206 #endif
207 #ifdef FAST_IPSEC
208         struct secpolicy *sp = NULL;
209         struct tdb_ident *tdbi;
210 #endif /* FAST_IPSEC */
211         struct sockaddr_in *next_hop = NULL;
212         int src_was_INADDR_ANY = 0;     /* as the name says... */
213
214         m = m0;
215         M_ASSERTPKTHDR(m);
216
217         if (ro == NULL) {
218                 ro = &iproute;
219                 bzero(ro, sizeof *ro);
220         } else if (ro->ro_rt != NULL && ro->ro_rt->rt_cpuid != mycpuid) {
221                 if (flags & IP_DEBUGROUTE) {
222                         if (route_assert_owner_access) {
223                                 panic("ip_output: "
224                                       "rt rt_cpuid %d accessed on cpu %d\n",
225                                       ro->ro_rt->rt_cpuid, mycpuid);
226                         } else {
227                                 kprintf("ip_output: "
228                                         "rt rt_cpuid %d accessed on cpu %d\n",
229                                         ro->ro_rt->rt_cpuid, mycpuid);
230                                 print_backtrace();
231                         }
232                 }
233
234                 /*
235                  * XXX
236                  * If the cached rtentry's owner CPU is not the current CPU,
237                  * then don't touch the cached rtentry (remote free is too
238                  * expensive in this context); just relocate the route.
239                  */
240                 ro = &iproute;
241                 bzero(ro, sizeof *ro);
242         }
243
244         if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
245                 /* Next hop */
246                 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
247                 KKASSERT(mtag != NULL);
248                 next_hop = m_tag_data(mtag);
249         }
250
251         if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
252                 struct dn_pkt *dn_pkt;
253
254                 /* Extract info from dummynet tag */
255                 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
256                 KKASSERT(mtag != NULL);
257                 dn_pkt = m_tag_data(mtag);
258
259                 /*
260                  * The packet was already tagged, so part of the
261                  * processing was already done, and we need to go down.
262                  * Get the calculated parameters from the tag.
263                  */
264                 ifp = dn_pkt->ifp;
265
266                 KKASSERT(ro == &iproute);
267                 *ro = dn_pkt->ro; /* structure copy */
268                 KKASSERT(ro->ro_rt == NULL || ro->ro_rt->rt_cpuid == mycpuid);
269
270                 dst = dn_pkt->dn_dst;
271                 if (dst == (struct sockaddr_in *)&(dn_pkt->ro.ro_dst)) {
272                         /* If 'dst' points into dummynet tag, adjust it */
273                         dst = (struct sockaddr_in *)&(ro->ro_dst);
274                 }
275
276                 ip = mtod(m, struct ip *);
277                 hlen = IP_VHL_HL(ip->ip_vhl) << 2 ;
278                 if (ro->ro_rt)
279                         ia = ifatoia(ro->ro_rt->rt_ifa);
280                 goto sendit;
281         }
282
283         if (opt) {
284                 len = 0;
285                 m = ip_insertoptions(m, opt, &len);
286                 if (len != 0)
287                         hlen = len;
288         }
289         ip = mtod(m, struct ip *);
290
291         /*
292          * Fill in IP header.
293          */
294         if (!(flags & (IP_FORWARDING|IP_RAWOUTPUT))) {
295                 ip->ip_vhl = IP_MAKE_VHL(IPVERSION, hlen >> 2);
296                 ip->ip_off &= IP_DF;
297                 ip->ip_id = ip_newid();
298                 ipstat.ips_localout++;
299         } else {
300                 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
301         }
302
303 reroute:
304         pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
305
306 #ifdef INVARIANTS
307         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
308                 /*
309                  * XXX
310                  * Multicast is not MPSAFE yet.  Caller must hold
311                  * BGL when output a multicast IP packet.
312                  */
313                 ASSERT_MP_LOCK_HELD(curthread);
314         }
315 #endif
316
317         dst = (struct sockaddr_in *)&ro->ro_dst;
318         /*
319          * If there is a cached route,
320          * check that it is to the same destination
321          * and is still up.  If not, free it and try again.
322          * The address family should also be checked in case of sharing the
323          * cache with IPv6.
324          */
325         if (ro->ro_rt &&
326             (!(ro->ro_rt->rt_flags & RTF_UP) ||
327              dst->sin_family != AF_INET ||
328              dst->sin_addr.s_addr != pkt_dst.s_addr)) {
329                 rtfree(ro->ro_rt);
330                 ro->ro_rt = NULL;
331         }
332         if (ro->ro_rt == NULL) {
333                 bzero(dst, sizeof *dst);
334                 dst->sin_family = AF_INET;
335                 dst->sin_len = sizeof *dst;
336                 dst->sin_addr = pkt_dst;
337         }
338         /*
339          * If routing to interface only,
340          * short circuit routing lookup.
341          */
342         if (flags & IP_ROUTETOIF) {
343                 if ((ia = ifatoia(ifa_ifwithdstaddr(sintosa(dst)))) == NULL &&
344                     (ia = ifatoia(ifa_ifwithnet(sintosa(dst)))) == NULL) {
345                         ipstat.ips_noroute++;
346                         error = ENETUNREACH;
347                         goto bad;
348                 }
349                 ifp = ia->ia_ifp;
350                 ip->ip_ttl = 1;
351                 isbroadcast = in_broadcast(dst->sin_addr, ifp);
352         } else if (IN_MULTICAST(ntohl(pkt_dst.s_addr)) &&
353                    imo != NULL && imo->imo_multicast_ifp != NULL) {
354                 /*
355                  * Bypass the normal routing lookup for multicast
356                  * packets if the interface is specified.
357                  */
358                 ifp = imo->imo_multicast_ifp;
359                 ia = IFP_TO_IA(ifp);
360                 isbroadcast = 0;        /* fool gcc */
361         } else {
362                 /*
363                  * If this is the case, we probably don't want to allocate
364                  * a protocol-cloned route since we didn't get one from the
365                  * ULP.  This lets TCP do its thing, while not burdening
366                  * forwarding or ICMP with the overhead of cloning a route.
367                  * Of course, we still want to do any cloning requested by
368                  * the link layer, as this is probably required in all cases
369                  * for correct operation (as it is for ARP).
370                  */
371                 if (ro->ro_rt == NULL)
372                         rtalloc_ign(ro, RTF_PRCLONING);
373                 if (ro->ro_rt == NULL) {
374                         ipstat.ips_noroute++;
375                         error = EHOSTUNREACH;
376                         goto bad;
377                 }
378                 ia = ifatoia(ro->ro_rt->rt_ifa);
379                 ifp = ro->ro_rt->rt_ifp;
380                 ro->ro_rt->rt_use++;
381                 if (ro->ro_rt->rt_flags & RTF_GATEWAY)
382                         dst = (struct sockaddr_in *)ro->ro_rt->rt_gateway;
383                 if (ro->ro_rt->rt_flags & RTF_HOST)
384                         isbroadcast = (ro->ro_rt->rt_flags & RTF_BROADCAST);
385                 else
386                         isbroadcast = in_broadcast(dst->sin_addr, ifp);
387         }
388         if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
389                 struct in_multi *inm;
390
391                 m->m_flags |= M_MCAST;
392                 /*
393                  * IP destination address is multicast.  Make sure "dst"
394                  * still points to the address in "ro".  (It may have been
395                  * changed to point to a gateway address, above.)
396                  */
397                 dst = (struct sockaddr_in *)&ro->ro_dst;
398                 /*
399                  * See if the caller provided any multicast options
400                  */
401                 if (imo != NULL) {
402                         ip->ip_ttl = imo->imo_multicast_ttl;
403                         if (imo->imo_multicast_vif != -1) {
404                                 ip->ip_src.s_addr =
405                                     ip_mcast_src ?
406                                     ip_mcast_src(imo->imo_multicast_vif) :
407                                     INADDR_ANY;
408                         }
409                 } else {
410                         ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
411                 }
412                 /*
413                  * Confirm that the outgoing interface supports multicast.
414                  */
415                 if ((imo == NULL) || (imo->imo_multicast_vif == -1)) {
416                         if (!(ifp->if_flags & IFF_MULTICAST)) {
417                                 ipstat.ips_noroute++;
418                                 error = ENETUNREACH;
419                                 goto bad;
420                         }
421                 }
422                 /*
423                  * If source address not specified yet, use address
424                  * of outgoing interface.
425                  */
426                 if (ip->ip_src.s_addr == INADDR_ANY) {
427                         /* Interface may have no addresses. */
428                         if (ia != NULL)
429                                 ip->ip_src = IA_SIN(ia)->sin_addr;
430                 }
431
432                 IN_LOOKUP_MULTI(pkt_dst, ifp, inm);
433                 if (inm != NULL &&
434                     (imo == NULL || imo->imo_multicast_loop)) {
435                         /*
436                          * If we belong to the destination multicast group
437                          * on the outgoing interface, and the caller did not
438                          * forbid loopback, loop back a copy.
439                          */
440                         ip_mloopback(ifp, m, dst, hlen);
441                 } else {
442                         /*
443                          * If we are acting as a multicast router, perform
444                          * multicast forwarding as if the packet had just
445                          * arrived on the interface to which we are about
446                          * to send.  The multicast forwarding function
447                          * recursively calls this function, using the
448                          * IP_FORWARDING flag to prevent infinite recursion.
449                          *
450                          * Multicasts that are looped back by ip_mloopback(),
451                          * above, will be forwarded by the ip_input() routine,
452                          * if necessary.
453                          */
454                         if (ip_mrouter && !(flags & IP_FORWARDING)) {
455                                 /*
456                                  * If rsvp daemon is not running, do not
457                                  * set ip_moptions. This ensures that the packet
458                                  * is multicast and not just sent down one link
459                                  * as prescribed by rsvpd.
460                                  */
461                                 if (!rsvp_on)
462                                         imo = NULL;
463                                 if (ip_mforward &&
464                                     ip_mforward(ip, ifp, m, imo) != 0) {
465                                         m_freem(m);
466                                         goto done;
467                                 }
468                         }
469                 }
470
471                 /*
472                  * Multicasts with a time-to-live of zero may be looped-
473                  * back, above, but must not be transmitted on a network.
474                  * Also, multicasts addressed to the loopback interface
475                  * are not sent -- the above call to ip_mloopback() will
476                  * loop back a copy if this host actually belongs to the
477                  * destination group on the loopback interface.
478                  */
479                 if (ip->ip_ttl == 0 || ifp->if_flags & IFF_LOOPBACK) {
480                         m_freem(m);
481                         goto done;
482                 }
483
484                 goto sendit;
485         } else {
486                 m->m_flags &= ~M_MCAST;
487         }
488
489         /*
490          * If the source address is not specified yet, use the address
491          * of the outoing interface. In case, keep note we did that, so
492          * if the the firewall changes the next-hop causing the output
493          * interface to change, we can fix that.
494          */
495         if (ip->ip_src.s_addr == INADDR_ANY || src_was_INADDR_ANY) {
496                 /* Interface may have no addresses. */
497                 if (ia != NULL) {
498                         ip->ip_src = IA_SIN(ia)->sin_addr;
499                         src_was_INADDR_ANY = 1;
500                 }
501         }
502
503 #ifdef ALTQ
504         /*
505          * Disable packet drop hack.
506          * Packetdrop should be done by queueing.
507          */
508 #else /* !ALTQ */
509         /*
510          * Verify that we have any chance at all of being able to queue
511          *      the packet or packet fragments
512          */
513         if ((ifp->if_snd.ifq_len + ip->ip_len / ifp->if_mtu + 1) >=
514             ifp->if_snd.ifq_maxlen) {
515                 error = ENOBUFS;
516                 ipstat.ips_odropped++;
517                 goto bad;
518         }
519 #endif /* !ALTQ */
520
521         /*
522          * Look for broadcast address and
523          * verify user is allowed to send
524          * such a packet.
525          */
526         if (isbroadcast) {
527                 if (!(ifp->if_flags & IFF_BROADCAST)) {
528                         error = EADDRNOTAVAIL;
529                         goto bad;
530                 }
531                 if (!(flags & IP_ALLOWBROADCAST)) {
532                         error = EACCES;
533                         goto bad;
534                 }
535                 /* don't allow broadcast messages to be fragmented */
536                 if (ip->ip_len > ifp->if_mtu) {
537                         error = EMSGSIZE;
538                         goto bad;
539                 }
540                 m->m_flags |= M_BCAST;
541         } else {
542                 m->m_flags &= ~M_BCAST;
543         }
544
545 sendit:
546 #ifdef IPSEC
547         /* get SP for this packet */
548         if (so == NULL)
549                 sp = ipsec4_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, flags, &error);
550         else
551                 sp = ipsec4_getpolicybysock(m, IPSEC_DIR_OUTBOUND, so, &error);
552
553         if (sp == NULL) {
554                 ipsecstat.out_inval++;
555                 goto bad;
556         }
557
558         error = 0;
559
560         /* check policy */
561         switch (sp->policy) {
562         case IPSEC_POLICY_DISCARD:
563                 /*
564                  * This packet is just discarded.
565                  */
566                 ipsecstat.out_polvio++;
567                 goto bad;
568
569         case IPSEC_POLICY_BYPASS:
570         case IPSEC_POLICY_NONE:
571                 /* no need to do IPsec. */
572                 goto skip_ipsec;
573
574         case IPSEC_POLICY_IPSEC:
575                 if (sp->req == NULL) {
576                         /* acquire a policy */
577                         error = key_spdacquire(sp);
578                         goto bad;
579                 }
580                 break;
581
582         case IPSEC_POLICY_ENTRUST:
583         default:
584                 kprintf("ip_output: Invalid policy found. %d\n", sp->policy);
585         }
586     {
587         struct ipsec_output_state state;
588         bzero(&state, sizeof state);
589         state.m = m;
590         if (flags & IP_ROUTETOIF) {
591                 state.ro = &iproute;
592                 bzero(&iproute, sizeof iproute);
593         } else
594                 state.ro = ro;
595         state.dst = (struct sockaddr *)dst;
596
597         ip->ip_sum = 0;
598
599         /*
600          * XXX
601          * delayed checksums are not currently compatible with IPsec
602          */
603         if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
604                 in_delayed_cksum(m);
605                 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
606         }
607
608         ip->ip_len = htons(ip->ip_len);
609         ip->ip_off = htons(ip->ip_off);
610
611         error = ipsec4_output(&state, sp, flags);
612
613         m = state.m;
614         if (flags & IP_ROUTETOIF) {
615                 /*
616                  * if we have tunnel mode SA, we may need to ignore
617                  * IP_ROUTETOIF.
618                  */
619                 if (state.ro != &iproute || state.ro->ro_rt != NULL) {
620                         flags &= ~IP_ROUTETOIF;
621                         ro = state.ro;
622                 }
623         } else
624                 ro = state.ro;
625         dst = (struct sockaddr_in *)state.dst;
626         if (error) {
627                 /* mbuf is already reclaimed in ipsec4_output. */
628                 m0 = NULL;
629                 switch (error) {
630                 case EHOSTUNREACH:
631                 case ENETUNREACH:
632                 case EMSGSIZE:
633                 case ENOBUFS:
634                 case ENOMEM:
635                         break;
636                 default:
637                         kprintf("ip4_output (ipsec): error code %d\n", error);
638                         /*fall through*/
639                 case ENOENT:
640                         /* don't show these error codes to the user */
641                         error = 0;
642                         break;
643                 }
644                 goto bad;
645         }
646     }
647
648         /* be sure to update variables that are affected by ipsec4_output() */
649         ip = mtod(m, struct ip *);
650 #ifdef _IP_VHL
651         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
652 #else
653         hlen = ip->ip_hl << 2;
654 #endif
655         if (ro->ro_rt == NULL) {
656                 if (!(flags & IP_ROUTETOIF)) {
657                         kprintf("ip_output: "
658                                 "can't update route after IPsec processing\n");
659                         error = EHOSTUNREACH;   /*XXX*/
660                         goto bad;
661                 }
662         } else {
663                 ia = ifatoia(ro->ro_rt->rt_ifa);
664                 ifp = ro->ro_rt->rt_ifp;
665         }
666
667         /* make it flipped, again. */
668         ip->ip_len = ntohs(ip->ip_len);
669         ip->ip_off = ntohs(ip->ip_off);
670 skip_ipsec:
671 #endif /*IPSEC*/
672 #ifdef FAST_IPSEC
673         /*
674          * Check the security policy (SP) for the packet and, if
675          * required, do IPsec-related processing.  There are two
676          * cases here; the first time a packet is sent through
677          * it will be untagged and handled by ipsec4_checkpolicy.
678          * If the packet is resubmitted to ip_output (e.g. after
679          * AH, ESP, etc. processing), there will be a tag to bypass
680          * the lookup and related policy checking.
681          */
682         mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
683         crit_enter();
684         if (mtag != NULL) {
685                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
686                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
687                 if (sp == NULL)
688                         error = -EINVAL;        /* force silent drop */
689                 m_tag_delete(m, mtag);
690         } else {
691                 sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND, flags,
692                                         &error, inp);
693         }
694         /*
695          * There are four return cases:
696          *    sp != NULL                    apply IPsec policy
697          *    sp == NULL, error == 0        no IPsec handling needed
698          *    sp == NULL, error == -EINVAL  discard packet w/o error
699          *    sp == NULL, error != 0        discard packet, report error
700          */
701         if (sp != NULL) {
702                 /* Loop detection, check if ipsec processing already done */
703                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
704                 for (mtag = m_tag_first(m); mtag != NULL;
705                      mtag = m_tag_next(m, mtag)) {
706                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
707                                 continue;
708                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
709                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
710                                 continue;
711                         /*
712                          * Check if policy has an SA associated with it.
713                          * This can happen when an SP has yet to acquire
714                          * an SA; e.g. on first reference.  If it occurs,
715                          * then we let ipsec4_process_packet do its thing.
716                          */
717                         if (sp->req->sav == NULL)
718                                 break;
719                         tdbi = (struct tdb_ident *)m_tag_data(mtag);
720                         if (tdbi->spi == sp->req->sav->spi &&
721                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
722                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
723                                  sizeof(union sockaddr_union)) == 0) {
724                                 /*
725                                  * No IPsec processing is needed, free
726                                  * reference to SP.
727                                  *
728                                  * NB: null pointer to avoid free at
729                                  *     done: below.
730                                  */
731                                 KEY_FREESP(&sp), sp = NULL;
732                                 crit_exit();
733                                 goto spd_done;
734                         }
735                 }
736
737                 /*
738                  * Do delayed checksums now because we send before
739                  * this is done in the normal processing path.
740                  */
741                 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
742                         in_delayed_cksum(m);
743                         m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
744                 }
745
746                 ip->ip_len = htons(ip->ip_len);
747                 ip->ip_off = htons(ip->ip_off);
748
749                 /* NB: callee frees mbuf */
750                 error = ipsec4_process_packet(m, sp->req, flags, 0);
751                 /*
752                  * Preserve KAME behaviour: ENOENT can be returned
753                  * when an SA acquire is in progress.  Don't propagate
754                  * this to user-level; it confuses applications.
755                  *
756                  * XXX this will go away when the SADB is redone.
757                  */
758                 if (error == ENOENT)
759                         error = 0;
760                 crit_exit();
761                 goto done;
762         } else {
763                 crit_exit();
764
765                 if (error != 0) {
766                         /*
767                          * Hack: -EINVAL is used to signal that a packet
768                          * should be silently discarded.  This is typically
769                          * because we asked key management for an SA and
770                          * it was delayed (e.g. kicked up to IKE).
771                          */
772                         if (error == -EINVAL)
773                                 error = 0;
774                         goto bad;
775                 } else {
776                         /* No IPsec processing for this packet. */
777                 }
778 #ifdef notyet
779                 /*
780                  * If deferred crypto processing is needed, check that
781                  * the interface supports it.
782                  */
783                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
784                 if (mtag != NULL && !(ifp->if_capenable & IFCAP_IPSEC)) {
785                         /* notify IPsec to do its own crypto */
786                         ipsp_skipcrypto_unmark((struct tdb_ident *)m_tag_data(mtag));
787                         error = EHOSTUNREACH;
788                         goto bad;
789                 }
790 #endif
791         }
792 spd_done:
793 #endif /* FAST_IPSEC */
794
795         /* We are already being fwd'd from a firewall. */
796         if (next_hop != NULL)
797                 goto pass;
798
799         /* No pfil hooks */
800         if (!pfil_has_hooks(&inet_pfil_hook)) {
801                 if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
802                         /*
803                          * Strip dummynet tags from stranded packets
804                          */
805                         mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
806                         KKASSERT(mtag != NULL);
807                         m_tag_delete(m, mtag);
808                         m->m_pkthdr.fw_flags &= ~DUMMYNET_MBUF_TAGGED;
809                 }
810                 goto pass;
811         }
812
813         /*
814          * IpHack's section.
815          * - Xlate: translate packet's addr/port (NAT).
816          * - Firewall: deny/allow/etc.
817          * - Wrap: fake packet's addr/port <unimpl.>
818          * - Encapsulate: put it in another IP and send out. <unimp.>
819          */
820
821         /*
822          * Run through list of hooks for output packets.
823          */
824         error = pfil_run_hooks(&inet_pfil_hook, &m, ifp, PFIL_OUT);
825         if (error != 0 || m == NULL)
826                 goto done;
827         ip = mtod(m, struct ip *);
828
829         if (m->m_pkthdr.fw_flags & IPFORWARD_MBUF_TAGGED) {
830                 /*
831                  * Check dst to make sure it is directly reachable on the
832                  * interface we previously thought it was.
833                  * If it isn't (which may be likely in some situations) we have
834                  * to re-route it (ie, find a route for the next-hop and the
835                  * associated interface) and set them here. This is nested
836                  * forwarding which in most cases is undesirable, except where
837                  * such control is nigh impossible. So we do it here.
838                  * And I'm babbling.
839                  */
840                 mtag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
841                 KKASSERT(mtag != NULL);
842                 next_hop = m_tag_data(mtag);
843
844                 /*
845                  * Try local forwarding first
846                  */
847                 if (ip_localforward(m, next_hop, hlen))
848                         goto done;
849
850                 /*
851                  * Relocate the route based on next_hop.
852                  * If the current route is inp's cache, keep it untouched.
853                  */
854                 if (ro == &iproute && ro->ro_rt != NULL) {
855                         RTFREE(ro->ro_rt);
856                         ro->ro_rt = NULL;
857                 }
858                 ro = &iproute;
859                 bzero(ro, sizeof *ro);
860
861                 /*
862                  * Forwarding to broadcast address is not allowed.
863                  * XXX Should we follow IP_ROUTETOIF?
864                  */
865                 flags &= ~(IP_ALLOWBROADCAST | IP_ROUTETOIF);
866
867                 /* We are doing forwarding now */
868                 flags |= IP_FORWARDING;
869
870                 goto reroute;
871         }
872
873         if (m->m_pkthdr.fw_flags & DUMMYNET_MBUF_TAGGED) {
874                 struct dn_pkt *dn_pkt;
875
876                 mtag = m_tag_find(m, PACKET_TAG_DUMMYNET, NULL);
877                 KKASSERT(mtag != NULL);
878                 dn_pkt = m_tag_data(mtag);
879
880                 /*
881                  * Under certain cases it is not possible to recalculate
882                  * 'ro' and 'dst', let alone 'flags', so just save them in
883                  * dummynet tag and avoid the possible wrong reculcalation
884                  * when we come back to ip_output() again.
885                  *
886                  * All other parameters have been already used and so they
887                  * are not needed anymore.
888                  * XXX if the ifp is deleted while a pkt is in dummynet,
889                  * we are in trouble! (TODO use ifnet_detach_event)
890                  *
891                  * We need to copy *ro because for ICMP pkts (and maybe
892                  * others) the caller passed a pointer into the stack;
893                  * dst might also be a pointer into *ro so it needs to
894                  * be updated.
895                  */
896                 dn_pkt->ro = *ro;
897                 if (ro->ro_rt)
898                         ro->ro_rt->rt_refcnt++;
899                 if (dst == (struct sockaddr_in *)&ro->ro_dst) {
900                         /* 'dst' points into 'ro' */
901                         dst = (struct sockaddr_in *)&(dn_pkt->ro.ro_dst);
902                 }
903                 dn_pkt->dn_dst = dst;
904                 dn_pkt->flags = flags;
905
906                 ip_dn_queue(m);
907                 goto done;
908         }
909 pass:
910         /* 127/8 must not appear on wire - RFC1122. */
911         if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
912             (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
913                 if (!(ifp->if_flags & IFF_LOOPBACK)) {
914                         ipstat.ips_badaddr++;
915                         error = EADDRNOTAVAIL;
916                         goto bad;
917                 }
918         }
919
920         m->m_pkthdr.csum_flags |= CSUM_IP;
921         sw_csum = m->m_pkthdr.csum_flags & ~ifp->if_hwassist;
922         if (sw_csum & CSUM_DELAY_DATA) {
923                 in_delayed_cksum(m);
924                 sw_csum &= ~CSUM_DELAY_DATA;
925         }
926         m->m_pkthdr.csum_flags &= ifp->if_hwassist;
927
928         /*
929          * If small enough for interface, or the interface will take
930          * care of the fragmentation for us, can just send directly.
931          */
932         if (ip->ip_len <= ifp->if_mtu || ((ifp->if_hwassist & CSUM_FRAGMENT) &&
933             !(ip->ip_off & IP_DF))) {
934                 ip->ip_len = htons(ip->ip_len);
935                 ip->ip_off = htons(ip->ip_off);
936                 ip->ip_sum = 0;
937                 if (sw_csum & CSUM_DELAY_IP) {
938                         if (ip->ip_vhl == IP_VHL_BORING)
939                                 ip->ip_sum = in_cksum_hdr(ip);
940                         else
941                                 ip->ip_sum = in_cksum(m, hlen);
942                 }
943
944                 /* Record statistics for this interface address. */
945                 if (!(flags & IP_FORWARDING) && ia) {
946                         ia->ia_ifa.if_opackets++;
947                         ia->ia_ifa.if_obytes += m->m_pkthdr.len;
948                 }
949
950 #ifdef IPSEC
951                 /* clean ipsec history once it goes out of the node */
952                 ipsec_delaux(m);
953 #endif
954
955 #ifdef MBUF_STRESS_TEST
956                 if (mbuf_frag_size && m->m_pkthdr.len > mbuf_frag_size) {
957                         struct mbuf *m1, *m2;
958                         int length, tmp;
959
960                         tmp = length = m->m_pkthdr.len;
961
962                         while ((length -= mbuf_frag_size) >= 1) {
963                                 m1 = m_split(m, length, MB_DONTWAIT);
964                                 if (m1 == NULL)
965                                         break;
966                                 m2 = m;
967                                 while (m2->m_next != NULL)
968                                         m2 = m2->m_next;
969                                 m2->m_next = m1;
970                         }
971                         m->m_pkthdr.len = tmp;
972                 }
973 #endif
974
975 #ifdef MPLS
976                 if (!mpls_output_process(m, ro->ro_rt))
977                         goto done;
978 #endif
979                 error = ifp->if_output(ifp, m, (struct sockaddr *)dst,
980                                        ro->ro_rt);
981                 goto done;
982         }
983
984         if (ip->ip_off & IP_DF) {
985                 error = EMSGSIZE;
986                 /*
987                  * This case can happen if the user changed the MTU
988                  * of an interface after enabling IP on it.  Because
989                  * most netifs don't keep track of routes pointing to
990                  * them, there is no way for one to update all its
991                  * routes when the MTU is changed.
992                  */
993                 if ((ro->ro_rt->rt_flags & (RTF_UP | RTF_HOST)) &&
994                     !(ro->ro_rt->rt_rmx.rmx_locks & RTV_MTU) &&
995                     (ro->ro_rt->rt_rmx.rmx_mtu > ifp->if_mtu)) {
996                         ro->ro_rt->rt_rmx.rmx_mtu = ifp->if_mtu;
997                 }
998                 ipstat.ips_cantfrag++;
999                 goto bad;
1000         }
1001
1002         /*
1003          * Too large for interface; fragment if possible. If successful,
1004          * on return, m will point to a list of packets to be sent.
1005          */
1006         error = ip_fragment(ip, &m, ifp->if_mtu, ifp->if_hwassist, sw_csum);
1007         if (error)
1008                 goto bad;
1009         for (; m; m = m0) {
1010                 m0 = m->m_nextpkt;
1011                 m->m_nextpkt = NULL;
1012 #ifdef IPSEC
1013                 /* clean ipsec history once it goes out of the node */
1014                 ipsec_delaux(m);
1015 #endif
1016                 if (error == 0) {
1017                         /* Record statistics for this interface address. */
1018                         if (ia != NULL) {
1019                                 ia->ia_ifa.if_opackets++;
1020                                 ia->ia_ifa.if_obytes += m->m_pkthdr.len;
1021                         }
1022 #ifdef MPLS
1023                         if (!mpls_output_process(m, ro->ro_rt))
1024                                 continue;
1025 #endif
1026                         error = ifp->if_output(ifp, m, (struct sockaddr *)dst,
1027                                                ro->ro_rt);
1028                 } else {
1029                         m_freem(m);
1030                 }
1031         }
1032
1033         if (error == 0)
1034                 ipstat.ips_fragmented++;
1035
1036 done:
1037         if (ro == &iproute && ro->ro_rt != NULL) {
1038                 RTFREE(ro->ro_rt);
1039                 ro->ro_rt = NULL;
1040         }
1041 #ifdef IPSEC
1042         if (sp != NULL) {
1043                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
1044                         kprintf("DP ip_output call free SP:%p\n", sp));
1045                 key_freesp(sp);
1046         }
1047 #endif
1048 #ifdef FAST_IPSEC
1049         if (sp != NULL)
1050                 KEY_FREESP(&sp);
1051 #endif
1052         return (error);
1053 bad:
1054         m_freem(m);
1055         goto done;
1056 }
1057
1058 /*
1059  * Create a chain of fragments which fit the given mtu. m_frag points to the
1060  * mbuf to be fragmented; on return it points to the chain with the fragments.
1061  * Return 0 if no error. If error, m_frag may contain a partially built
1062  * chain of fragments that should be freed by the caller.
1063  *
1064  * if_hwassist_flags is the hw offload capabilities (see if_data.ifi_hwassist)
1065  * sw_csum contains the delayed checksums flags (e.g., CSUM_DELAY_IP).
1066  */
1067 int
1068 ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
1069             u_long if_hwassist_flags, int sw_csum)
1070 {
1071         int error = 0;
1072         int hlen = IP_VHL_HL(ip->ip_vhl) << 2;
1073         int len = (mtu - hlen) & ~7;    /* size of payload in each fragment */
1074         int off;
1075         struct mbuf *m0 = *m_frag;      /* the original packet          */
1076         int firstlen;
1077         struct mbuf **mnext;
1078         int nfrags;
1079
1080         if (ip->ip_off & IP_DF) {       /* Fragmentation not allowed */
1081                 ipstat.ips_cantfrag++;
1082                 return EMSGSIZE;
1083         }
1084
1085         /*
1086          * Must be able to put at least 8 bytes per fragment.
1087          */
1088         if (len < 8)
1089                 return EMSGSIZE;
1090
1091         /*
1092          * If the interface will not calculate checksums on
1093          * fragmented packets, then do it here.
1094          */
1095         if ((m0->m_pkthdr.csum_flags & CSUM_DELAY_DATA) &&
1096             !(if_hwassist_flags & CSUM_IP_FRAGS)) {
1097                 in_delayed_cksum(m0);
1098                 m0->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
1099         }
1100
1101         if (len > PAGE_SIZE) {
1102                 /*
1103                  * Fragment large datagrams such that each segment
1104                  * contains a multiple of PAGE_SIZE amount of data,
1105                  * plus headers. This enables a receiver to perform
1106                  * page-flipping zero-copy optimizations.
1107                  *
1108                  * XXX When does this help given that sender and receiver
1109                  * could have different page sizes, and also mtu could
1110                  * be less than the receiver's page size ?
1111                  */
1112                 int newlen;
1113                 struct mbuf *m;
1114
1115                 for (m = m0, off = 0; m && (off+m->m_len) <= mtu; m = m->m_next)
1116                         off += m->m_len;
1117
1118                 /*
1119                  * firstlen (off - hlen) must be aligned on an
1120                  * 8-byte boundary
1121                  */
1122                 if (off < hlen)
1123                         goto smart_frag_failure;
1124                 off = ((off - hlen) & ~7) + hlen;
1125                 newlen = (~PAGE_MASK) & mtu;
1126                 if ((newlen + sizeof(struct ip)) > mtu) {
1127                         /* we failed, go back the default */
1128 smart_frag_failure:
1129                         newlen = len;
1130                         off = hlen + len;
1131                 }
1132                 len = newlen;
1133
1134         } else {
1135                 off = hlen + len;
1136         }
1137
1138         firstlen = off - hlen;
1139         mnext = &m0->m_nextpkt;         /* pointer to next packet */
1140
1141         /*
1142          * Loop through length of segment after first fragment,
1143          * make new header and copy data of each part and link onto chain.
1144          * Here, m0 is the original packet, m is the fragment being created.
1145          * The fragments are linked off the m_nextpkt of the original
1146          * packet, which after processing serves as the first fragment.
1147          */
1148         for (nfrags = 1; off < ip->ip_len; off += len, nfrags++) {
1149                 struct ip *mhip;        /* ip header on the fragment */
1150                 struct mbuf *m;
1151                 int mhlen = sizeof(struct ip);
1152
1153                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
1154                 if (m == NULL) {
1155                         error = ENOBUFS;
1156                         ipstat.ips_odropped++;
1157                         goto done;
1158                 }
1159                 m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG;
1160                 /*
1161                  * In the first mbuf, leave room for the link header, then
1162                  * copy the original IP header including options. The payload
1163                  * goes into an additional mbuf chain returned by m_copy().
1164                  */
1165                 m->m_data += max_linkhdr;
1166                 mhip = mtod(m, struct ip *);
1167                 *mhip = *ip;
1168                 if (hlen > sizeof(struct ip)) {
1169                         mhlen = ip_optcopy(ip, mhip) + sizeof(struct ip);
1170                         mhip->ip_vhl = IP_MAKE_VHL(IPVERSION, mhlen >> 2);
1171                 }
1172                 m->m_len = mhlen;
1173                 /* XXX do we need to add ip->ip_off below ? */
1174                 mhip->ip_off = ((off - hlen) >> 3) + ip->ip_off;
1175                 if (off + len >= ip->ip_len) {  /* last fragment */
1176                         len = ip->ip_len - off;
1177                         m->m_flags |= M_LASTFRAG;
1178                 } else
1179                         mhip->ip_off |= IP_MF;
1180                 mhip->ip_len = htons((u_short)(len + mhlen));
1181                 m->m_next = m_copy(m0, off, len);
1182                 if (m->m_next == NULL) {                /* copy failed */
1183                         m_free(m);
1184                         error = ENOBUFS;        /* ??? */
1185                         ipstat.ips_odropped++;
1186                         goto done;
1187                 }
1188                 m->m_pkthdr.len = mhlen + len;
1189                 m->m_pkthdr.rcvif = NULL;
1190                 m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
1191                 mhip->ip_off = htons(mhip->ip_off);
1192                 mhip->ip_sum = 0;
1193                 if (sw_csum & CSUM_DELAY_IP)
1194                         mhip->ip_sum = in_cksum(m, mhlen);
1195                 *mnext = m;
1196                 mnext = &m->m_nextpkt;
1197         }
1198         ipstat.ips_ofragments += nfrags;
1199
1200         /* set first marker for fragment chain */
1201         m0->m_flags |= M_FIRSTFRAG | M_FRAG;
1202         m0->m_pkthdr.csum_data = nfrags;
1203
1204         /*
1205          * Update first fragment by trimming what's been copied out
1206          * and updating header.
1207          */
1208         m_adj(m0, hlen + firstlen - ip->ip_len);
1209         m0->m_pkthdr.len = hlen + firstlen;
1210         ip->ip_len = htons((u_short)m0->m_pkthdr.len);
1211         ip->ip_off |= IP_MF;
1212         ip->ip_off = htons(ip->ip_off);
1213         ip->ip_sum = 0;
1214         if (sw_csum & CSUM_DELAY_IP)
1215                 ip->ip_sum = in_cksum(m0, hlen);
1216
1217 done:
1218         *m_frag = m0;
1219         return error;
1220 }
1221
1222 void
1223 in_delayed_cksum(struct mbuf *m)
1224 {
1225         struct ip *ip;
1226         u_short csum, offset;
1227
1228         ip = mtod(m, struct ip *);
1229         offset = IP_VHL_HL(ip->ip_vhl) << 2 ;
1230         csum = in_cksum_skip(m, ip->ip_len, offset);
1231         if (m->m_pkthdr.csum_flags & CSUM_UDP && csum == 0)
1232                 csum = 0xffff;
1233         offset += m->m_pkthdr.csum_data;        /* checksum offset */
1234
1235         if (offset + sizeof(u_short) > m->m_len) {
1236                 kprintf("delayed m_pullup, m->len: %d  off: %d  p: %d\n",
1237                     m->m_len, offset, ip->ip_p);
1238                 /*
1239                  * XXX
1240                  * this shouldn't happen, but if it does, the
1241                  * correct behavior may be to insert the checksum
1242                  * in the existing chain instead of rearranging it.
1243                  */
1244                 m = m_pullup(m, offset + sizeof(u_short));
1245         }
1246         *(u_short *)(m->m_data + offset) = csum;
1247 }
1248
1249 /*
1250  * Insert IP options into preformed packet.
1251  * Adjust IP destination as required for IP source routing,
1252  * as indicated by a non-zero in_addr at the start of the options.
1253  *
1254  * XXX This routine assumes that the packet has no options in place.
1255  */
1256 static struct mbuf *
1257 ip_insertoptions(struct mbuf *m, struct mbuf *opt, int *phlen)
1258 {
1259         struct ipoption *p = mtod(opt, struct ipoption *);
1260         struct mbuf *n;
1261         struct ip *ip = mtod(m, struct ip *);
1262         unsigned optlen;
1263
1264         optlen = opt->m_len - sizeof p->ipopt_dst;
1265         if (optlen + (u_short)ip->ip_len > IP_MAXPACKET) {
1266                 *phlen = 0;
1267                 return (m);             /* XXX should fail */
1268         }
1269         if (p->ipopt_dst.s_addr)
1270                 ip->ip_dst = p->ipopt_dst;
1271         if (m->m_flags & M_EXT || m->m_data - optlen < m->m_pktdat) {
1272                 MGETHDR(n, MB_DONTWAIT, MT_HEADER);
1273                 if (n == NULL) {
1274                         *phlen = 0;
1275                         return (m);
1276                 }
1277                 n->m_pkthdr.rcvif = NULL;
1278                 n->m_pkthdr.len = m->m_pkthdr.len + optlen;
1279                 m->m_len -= sizeof(struct ip);
1280                 m->m_data += sizeof(struct ip);
1281                 n->m_next = m;
1282                 m = n;
1283                 m->m_len = optlen + sizeof(struct ip);
1284                 m->m_data += max_linkhdr;
1285                 memcpy(mtod(m, void *), ip, sizeof(struct ip));
1286         } else {
1287                 m->m_data -= optlen;
1288                 m->m_len += optlen;
1289                 m->m_pkthdr.len += optlen;
1290                 ovbcopy(ip, mtod(m, caddr_t), sizeof(struct ip));
1291         }
1292         ip = mtod(m, struct ip *);
1293         bcopy(p->ipopt_list, ip + 1, optlen);
1294         *phlen = sizeof(struct ip) + optlen;
1295         ip->ip_vhl = IP_MAKE_VHL(IPVERSION, *phlen >> 2);
1296         ip->ip_len += optlen;
1297         return (m);
1298 }
1299
1300 /*
1301  * Copy options from ip to jp,
1302  * omitting those not copied during fragmentation.
1303  */
1304 int
1305 ip_optcopy(struct ip *ip, struct ip *jp)
1306 {
1307         u_char *cp, *dp;
1308         int opt, optlen, cnt;
1309
1310         cp = (u_char *)(ip + 1);
1311         dp = (u_char *)(jp + 1);
1312         cnt = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
1313         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1314                 opt = cp[0];
1315                 if (opt == IPOPT_EOL)
1316                         break;
1317                 if (opt == IPOPT_NOP) {
1318                         /* Preserve for IP mcast tunnel's LSRR alignment. */
1319                         *dp++ = IPOPT_NOP;
1320                         optlen = 1;
1321                         continue;
1322                 }
1323
1324                 KASSERT(cnt >= IPOPT_OLEN + sizeof *cp,
1325                     ("ip_optcopy: malformed ipv4 option"));
1326                 optlen = cp[IPOPT_OLEN];
1327                 KASSERT(optlen >= IPOPT_OLEN + sizeof *cp && optlen <= cnt,
1328                     ("ip_optcopy: malformed ipv4 option"));
1329
1330                 /* bogus lengths should have been caught by ip_dooptions */
1331                 if (optlen > cnt)
1332                         optlen = cnt;
1333                 if (IPOPT_COPIED(opt)) {
1334                         bcopy(cp, dp, optlen);
1335                         dp += optlen;
1336                 }
1337         }
1338         for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
1339                 *dp++ = IPOPT_EOL;
1340         return (optlen);
1341 }
1342
1343 /*
1344  * IP socket option processing.
1345  */
1346 int
1347 ip_ctloutput(struct socket *so, struct sockopt *sopt)
1348 {
1349         struct  inpcb *inp = so->so_pcb;
1350         int     error, optval;
1351
1352         error = optval = 0;
1353         if (sopt->sopt_level != IPPROTO_IP) {
1354                 return (EINVAL);
1355         }
1356
1357         switch (sopt->sopt_dir) {
1358         case SOPT_SET:
1359                 switch (sopt->sopt_name) {
1360                 case IP_OPTIONS:
1361 #ifdef notyet
1362                 case IP_RETOPTS:
1363 #endif
1364                 {
1365                         struct mbuf *m;
1366                         if (sopt->sopt_valsize > MLEN) {
1367                                 error = EMSGSIZE;
1368                                 break;
1369                         }
1370                         MGET(m, sopt->sopt_td ? MB_WAIT : MB_DONTWAIT, MT_HEADER);
1371                         if (m == NULL) {
1372                                 error = ENOBUFS;
1373                                 break;
1374                         }
1375                         m->m_len = sopt->sopt_valsize;
1376                         error = soopt_to_kbuf(sopt, mtod(m, void *), m->m_len,
1377                                               m->m_len);
1378                         return (ip_pcbopts(sopt->sopt_name, &inp->inp_options,
1379                                            m));
1380                 }
1381
1382                 case IP_TOS:
1383                 case IP_TTL:
1384                 case IP_MINTTL:
1385                 case IP_RECVOPTS:
1386                 case IP_RECVRETOPTS:
1387                 case IP_RECVDSTADDR:
1388                 case IP_RECVIF:
1389                 case IP_RECVTTL:
1390                 case IP_FAITH:
1391                         error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1392                                              sizeof optval);
1393                         if (error)
1394                                 break;
1395                         switch (sopt->sopt_name) {
1396                         case IP_TOS:
1397                                 inp->inp_ip_tos = optval;
1398                                 break;
1399
1400                         case IP_TTL:
1401                                 inp->inp_ip_ttl = optval;
1402                                 break;
1403                         case IP_MINTTL:
1404                                 if (optval >= 0 && optval <= MAXTTL)
1405                                         inp->inp_ip_minttl = optval;
1406                                 else
1407                                         error = EINVAL;
1408                                 break;
1409 #define OPTSET(bit) \
1410         if (optval) \
1411                 inp->inp_flags |= bit; \
1412         else \
1413                 inp->inp_flags &= ~bit;
1414
1415                         case IP_RECVOPTS:
1416                                 OPTSET(INP_RECVOPTS);
1417                                 break;
1418
1419                         case IP_RECVRETOPTS:
1420                                 OPTSET(INP_RECVRETOPTS);
1421                                 break;
1422
1423                         case IP_RECVDSTADDR:
1424                                 OPTSET(INP_RECVDSTADDR);
1425                                 break;
1426
1427                         case IP_RECVIF:
1428                                 OPTSET(INP_RECVIF);
1429                                 break;
1430
1431                         case IP_RECVTTL:
1432                                 OPTSET(INP_RECVTTL);
1433                                 break;
1434
1435                         case IP_FAITH:
1436                                 OPTSET(INP_FAITH);
1437                                 break;
1438                         }
1439                         break;
1440 #undef OPTSET
1441
1442                 case IP_MULTICAST_IF:
1443                 case IP_MULTICAST_VIF:
1444                 case IP_MULTICAST_TTL:
1445                 case IP_MULTICAST_LOOP:
1446                 case IP_ADD_MEMBERSHIP:
1447                 case IP_DROP_MEMBERSHIP:
1448                         error = ip_setmoptions(sopt, &inp->inp_moptions);
1449                         break;
1450
1451                 case IP_PORTRANGE:
1452                         error = soopt_to_kbuf(sopt, &optval, sizeof optval,
1453                                             sizeof optval);
1454                         if (error)
1455                                 break;
1456
1457                         switch (optval) {
1458                         case IP_PORTRANGE_DEFAULT:
1459                                 inp->inp_flags &= ~(INP_LOWPORT);
1460                                 inp->inp_flags &= ~(INP_HIGHPORT);
1461                                 break;
1462
1463                         case IP_PORTRANGE_HIGH:
1464                                 inp->inp_flags &= ~(INP_LOWPORT);
1465                                 inp->inp_flags |= INP_HIGHPORT;
1466                                 break;
1467
1468                         case IP_PORTRANGE_LOW:
1469                                 inp->inp_flags &= ~(INP_HIGHPORT);
1470                                 inp->inp_flags |= INP_LOWPORT;
1471                                 break;
1472
1473                         default:
1474                                 error = EINVAL;
1475                                 break;
1476                         }
1477                         break;
1478
1479 #if defined(IPSEC) || defined(FAST_IPSEC)
1480                 case IP_IPSEC_POLICY:
1481                 {
1482                         caddr_t req;
1483                         size_t len = 0;
1484                         int priv;
1485                         struct mbuf *m;
1486                         int optname;
1487
1488                         if ((error = soopt_getm(sopt, &m)) != 0) /* XXX */
1489                                 break;
1490                         soopt_to_mbuf(sopt, m);
1491                         priv = (sopt->sopt_td != NULL &&
1492                                 priv_check(sopt->sopt_td, PRIV_ROOT) != 0) ? 0 : 1;
1493                         req = mtod(m, caddr_t);
1494                         len = m->m_len;
1495                         optname = sopt->sopt_name;
1496                         error = ipsec4_set_policy(inp, optname, req, len, priv);
1497                         m_freem(m);
1498                         break;
1499                 }
1500 #endif /*IPSEC*/
1501
1502                 default:
1503                         error = ENOPROTOOPT;
1504                         break;
1505                 }
1506                 break;
1507
1508         case SOPT_GET:
1509                 switch (sopt->sopt_name) {
1510                 case IP_OPTIONS:
1511                 case IP_RETOPTS:
1512                         if (inp->inp_options)
1513                                 soopt_from_kbuf(sopt, mtod(inp->inp_options,
1514                                                            char *),
1515                                                 inp->inp_options->m_len);
1516                         else
1517                                 sopt->sopt_valsize = 0;
1518                         break;
1519
1520                 case IP_TOS:
1521                 case IP_TTL:
1522                 case IP_MINTTL:
1523                 case IP_RECVOPTS:
1524                 case IP_RECVRETOPTS:
1525                 case IP_RECVDSTADDR:
1526                 case IP_RECVTTL:
1527                 case IP_RECVIF:
1528                 case IP_PORTRANGE:
1529                 case IP_FAITH:
1530                         switch (sopt->sopt_name) {
1531
1532                         case IP_TOS:
1533                                 optval = inp->inp_ip_tos;
1534                                 break;
1535
1536                         case IP_TTL:
1537                                 optval = inp->inp_ip_ttl;
1538                                 break;
1539                         case IP_MINTTL:
1540                                 optval = inp->inp_ip_minttl;
1541                                 break;
1542
1543 #define OPTBIT(bit)     (inp->inp_flags & bit ? 1 : 0)
1544
1545                         case IP_RECVOPTS:
1546                                 optval = OPTBIT(INP_RECVOPTS);
1547                                 break;
1548
1549                         case IP_RECVRETOPTS:
1550                                 optval = OPTBIT(INP_RECVRETOPTS);
1551                                 break;
1552
1553                         case IP_RECVDSTADDR:
1554                                 optval = OPTBIT(INP_RECVDSTADDR);
1555                                 break;
1556
1557                         case IP_RECVTTL:
1558                                 optval = OPTBIT(INP_RECVTTL);
1559                                 break;
1560
1561                         case IP_RECVIF:
1562                                 optval = OPTBIT(INP_RECVIF);
1563                                 break;
1564
1565                         case IP_PORTRANGE:
1566                                 if (inp->inp_flags & INP_HIGHPORT)
1567                                         optval = IP_PORTRANGE_HIGH;
1568                                 else if (inp->inp_flags & INP_LOWPORT)
1569                                         optval = IP_PORTRANGE_LOW;
1570                                 else
1571                                         optval = 0;
1572                                 break;
1573
1574                         case IP_FAITH:
1575                                 optval = OPTBIT(INP_FAITH);
1576                                 break;
1577                         }
1578                         soopt_from_kbuf(sopt, &optval, sizeof optval);
1579                         break;
1580
1581                 case IP_MULTICAST_IF:
1582                 case IP_MULTICAST_VIF:
1583                 case IP_MULTICAST_TTL:
1584                 case IP_MULTICAST_LOOP:
1585                 case IP_ADD_MEMBERSHIP:
1586                 case IP_DROP_MEMBERSHIP:
1587                         error = ip_getmoptions(sopt, inp->inp_moptions);
1588                         break;
1589
1590 #if defined(IPSEC) || defined(FAST_IPSEC)
1591                 case IP_IPSEC_POLICY:
1592                 {
1593                         struct mbuf *m = NULL;
1594                         caddr_t req = NULL;
1595                         size_t len = 0;
1596
1597                         if (m != NULL) {
1598                                 req = mtod(m, caddr_t);
1599                                 len = m->m_len;
1600                         }
1601                         error = ipsec4_get_policy(so->so_pcb, req, len, &m);
1602                         if (error == 0)
1603                                 error = soopt_from_mbuf(sopt, m); /* XXX */
1604                         if (error == 0)
1605                                 m_freem(m);
1606                         break;
1607                 }
1608 #endif /*IPSEC*/
1609
1610                 default:
1611                         error = ENOPROTOOPT;
1612                         break;
1613                 }
1614                 break;
1615         }
1616         return (error);
1617 }
1618
1619 /*
1620  * Set up IP options in pcb for insertion in output packets.
1621  * Store in mbuf with pointer in pcbopt, adding pseudo-option
1622  * with destination address if source routed.
1623  */
1624 static int
1625 ip_pcbopts(int optname, struct mbuf **pcbopt, struct mbuf *m)
1626 {
1627         int cnt, optlen;
1628         u_char *cp;
1629         u_char opt;
1630
1631         /* turn off any old options */
1632         if (*pcbopt)
1633                 m_free(*pcbopt);
1634         *pcbopt = 0;
1635         if (m == NULL || m->m_len == 0) {
1636                 /*
1637                  * Only turning off any previous options.
1638                  */
1639                 if (m != NULL)
1640                         m_free(m);
1641                 return (0);
1642         }
1643
1644         if (m->m_len % sizeof(int32_t))
1645                 goto bad;
1646         /*
1647          * IP first-hop destination address will be stored before
1648          * actual options; move other options back
1649          * and clear it when none present.
1650          */
1651         if (m->m_data + m->m_len + sizeof(struct in_addr) >= &m->m_dat[MLEN])
1652                 goto bad;
1653         cnt = m->m_len;
1654         m->m_len += sizeof(struct in_addr);
1655         cp = mtod(m, u_char *) + sizeof(struct in_addr);
1656         ovbcopy(mtod(m, caddr_t), cp, cnt);
1657         bzero(mtod(m, caddr_t), sizeof(struct in_addr));
1658
1659         for (; cnt > 0; cnt -= optlen, cp += optlen) {
1660                 opt = cp[IPOPT_OPTVAL];
1661                 if (opt == IPOPT_EOL)
1662                         break;
1663                 if (opt == IPOPT_NOP)
1664                         optlen = 1;
1665                 else {
1666                         if (cnt < IPOPT_OLEN + sizeof *cp)
1667                                 goto bad;
1668                         optlen = cp[IPOPT_OLEN];
1669                         if (optlen < IPOPT_OLEN + sizeof *cp || optlen > cnt)
1670                                 goto bad;
1671                 }
1672                 switch (opt) {
1673
1674                 default:
1675                         break;
1676
1677                 case IPOPT_LSRR:
1678                 case IPOPT_SSRR:
1679                         /*
1680                          * user process specifies route as:
1681                          *      ->A->B->C->D
1682                          * D must be our final destination (but we can't
1683                          * check that since we may not have connected yet).
1684                          * A is first hop destination, which doesn't appear in
1685                          * actual IP option, but is stored before the options.
1686                          */
1687                         if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
1688                                 goto bad;
1689                         m->m_len -= sizeof(struct in_addr);
1690                         cnt -= sizeof(struct in_addr);
1691                         optlen -= sizeof(struct in_addr);
1692                         cp[IPOPT_OLEN] = optlen;
1693                         /*
1694                          * Move first hop before start of options.
1695                          */
1696                         bcopy(&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
1697                               sizeof(struct in_addr));
1698                         /*
1699                          * Then copy rest of options back
1700                          * to close up the deleted entry.
1701                          */
1702                         ovbcopy(&cp[IPOPT_OFFSET+1] + sizeof(struct in_addr),
1703                                 &cp[IPOPT_OFFSET+1],
1704                                 cnt - (IPOPT_MINOFF - 1));
1705                         break;
1706                 }
1707         }
1708         if (m->m_len > MAX_IPOPTLEN + sizeof(struct in_addr))
1709                 goto bad;
1710         *pcbopt = m;
1711         return (0);
1712
1713 bad:
1714         m_free(m);
1715         return (EINVAL);
1716 }
1717
1718 /*
1719  * XXX
1720  * The whole multicast option thing needs to be re-thought.
1721  * Several of these options are equally applicable to non-multicast
1722  * transmission, and one (IP_MULTICAST_TTL) totally duplicates a
1723  * standard option (IP_TTL).
1724  */
1725
1726 /*
1727  * following RFC1724 section 3.3, 0.0.0.0/8 is interpreted as interface index.
1728  */
1729 static struct ifnet *
1730 ip_multicast_if(struct in_addr *a, int *ifindexp)
1731 {
1732         int ifindex;
1733         struct ifnet *ifp;
1734
1735         if (ifindexp)
1736                 *ifindexp = 0;
1737         if (ntohl(a->s_addr) >> 24 == 0) {
1738                 ifindex = ntohl(a->s_addr) & 0xffffff;
1739                 if (ifindex < 0 || if_index < ifindex)
1740                         return NULL;
1741                 ifp = ifindex2ifnet[ifindex];
1742                 if (ifindexp)
1743                         *ifindexp = ifindex;
1744         } else {
1745                 ifp = INADDR_TO_IFP(a);
1746         }
1747         return ifp;
1748 }
1749
1750 /*
1751  * Set the IP multicast options in response to user setsockopt().
1752  */
1753 static int
1754 ip_setmoptions(struct sockopt *sopt, struct ip_moptions **imop)
1755 {
1756         int error = 0;
1757         int i;
1758         struct in_addr addr;
1759         struct ip_mreq mreq;
1760         struct ifnet *ifp;
1761         struct ip_moptions *imo = *imop;
1762         int ifindex;
1763
1764         if (imo == NULL) {
1765                 /*
1766                  * No multicast option buffer attached to the pcb;
1767                  * allocate one and initialize to default values.
1768                  */
1769                 imo = kmalloc(sizeof *imo, M_IPMOPTS, M_WAITOK);
1770
1771                 *imop = imo;
1772                 imo->imo_multicast_ifp = NULL;
1773                 imo->imo_multicast_addr.s_addr = INADDR_ANY;
1774                 imo->imo_multicast_vif = -1;
1775                 imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
1776                 imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
1777                 imo->imo_num_memberships = 0;
1778         }
1779         switch (sopt->sopt_name) {
1780         /* store an index number for the vif you wanna use in the send */
1781         case IP_MULTICAST_VIF:
1782                 if (legal_vif_num == 0) {
1783                         error = EOPNOTSUPP;
1784                         break;
1785                 }
1786                 error = soopt_to_kbuf(sopt, &i, sizeof i, sizeof i);
1787                 if (error)
1788                         break;
1789                 if (!legal_vif_num(i) && (i != -1)) {
1790                         error = EINVAL;
1791                         break;
1792                 }
1793                 imo->imo_multicast_vif = i;
1794                 break;
1795
1796         case IP_MULTICAST_IF:
1797                 /*
1798                  * Select the interface for outgoing multicast packets.
1799                  */
1800                 error = soopt_to_kbuf(sopt, &addr, sizeof addr, sizeof addr);
1801                 if (error)
1802                         break;
1803
1804                 /*
1805                  * INADDR_ANY is used to remove a previous selection.
1806                  * When no interface is selected, a default one is
1807                  * chosen every time a multicast packet is sent.
1808                  */
1809                 if (addr.s_addr == INADDR_ANY) {
1810                         imo->imo_multicast_ifp = NULL;
1811                         break;
1812                 }
1813                 /*
1814                  * The selected interface is identified by its local
1815                  * IP address.  Find the interface and confirm that
1816                  * it supports multicasting.
1817                  */
1818                 crit_enter();
1819                 ifp = ip_multicast_if(&addr, &ifindex);
1820                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1821                         crit_exit();
1822                         error = EADDRNOTAVAIL;
1823                         break;
1824                 }
1825                 imo->imo_multicast_ifp = ifp;
1826                 if (ifindex)
1827                         imo->imo_multicast_addr = addr;
1828                 else
1829                         imo->imo_multicast_addr.s_addr = INADDR_ANY;
1830                 crit_exit();
1831                 break;
1832
1833         case IP_MULTICAST_TTL:
1834                 /*
1835                  * Set the IP time-to-live for outgoing multicast packets.
1836                  * The original multicast API required a char argument,
1837                  * which is inconsistent with the rest of the socket API.
1838                  * We allow either a char or an int.
1839                  */
1840                 if (sopt->sopt_valsize == 1) {
1841                         u_char ttl;
1842                         error = soopt_to_kbuf(sopt, &ttl, 1, 1);
1843                         if (error)
1844                                 break;
1845                         imo->imo_multicast_ttl = ttl;
1846                 } else {
1847                         u_int ttl;
1848                         error = soopt_to_kbuf(sopt, &ttl, sizeof ttl, sizeof ttl);
1849                         if (error)
1850                                 break;
1851                         if (ttl > 255)
1852                                 error = EINVAL;
1853                         else
1854                                 imo->imo_multicast_ttl = ttl;
1855                 }
1856                 break;
1857
1858         case IP_MULTICAST_LOOP:
1859                 /*
1860                  * Set the loopback flag for outgoing multicast packets.
1861                  * Must be zero or one.  The original multicast API required a
1862                  * char argument, which is inconsistent with the rest
1863                  * of the socket API.  We allow either a char or an int.
1864                  */
1865                 if (sopt->sopt_valsize == 1) {
1866                         u_char loop;
1867
1868                         error = soopt_to_kbuf(sopt, &loop, 1, 1);
1869                         if (error)
1870                                 break;
1871                         imo->imo_multicast_loop = !!loop;
1872                 } else {
1873                         u_int loop;
1874
1875                         error = soopt_to_kbuf(sopt, &loop, sizeof loop,
1876                                             sizeof loop);
1877                         if (error)
1878                                 break;
1879                         imo->imo_multicast_loop = !!loop;
1880                 }
1881                 break;
1882
1883         case IP_ADD_MEMBERSHIP:
1884                 /*
1885                  * Add a multicast group membership.
1886                  * Group must be a valid IP multicast address.
1887                  */
1888                 error = soopt_to_kbuf(sopt, &mreq, sizeof mreq, sizeof mreq);
1889                 if (error)
1890                         break;
1891
1892                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1893                         error = EINVAL;
1894                         break;
1895                 }
1896                 crit_enter();
1897                 /*
1898                  * If no interface address was provided, use the interface of
1899                  * the route to the given multicast address.
1900                  */
1901                 if (mreq.imr_interface.s_addr == INADDR_ANY) {
1902                         struct sockaddr_in dst;
1903                         struct rtentry *rt;
1904
1905                         bzero(&dst, sizeof(struct sockaddr_in));
1906                         dst.sin_len = sizeof(struct sockaddr_in);
1907                         dst.sin_family = AF_INET;
1908                         dst.sin_addr = mreq.imr_multiaddr;
1909                         rt = rtlookup((struct sockaddr *)&dst);
1910                         if (rt == NULL) {
1911                                 error = EADDRNOTAVAIL;
1912                                 crit_exit();
1913                                 break;
1914                         }
1915                         --rt->rt_refcnt;
1916                         ifp = rt->rt_ifp;
1917                 } else {
1918                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1919                 }
1920
1921                 /*
1922                  * See if we found an interface, and confirm that it
1923                  * supports multicast.
1924                  */
1925                 if (ifp == NULL || !(ifp->if_flags & IFF_MULTICAST)) {
1926                         error = EADDRNOTAVAIL;
1927                         crit_exit();
1928                         break;
1929                 }
1930                 /*
1931                  * See if the membership already exists or if all the
1932                  * membership slots are full.
1933                  */
1934                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1935                         if (imo->imo_membership[i]->inm_ifp == ifp &&
1936                             imo->imo_membership[i]->inm_addr.s_addr
1937                                                 == mreq.imr_multiaddr.s_addr)
1938                                 break;
1939                 }
1940                 if (i < imo->imo_num_memberships) {
1941                         error = EADDRINUSE;
1942                         crit_exit();
1943                         break;
1944                 }
1945                 if (i == IP_MAX_MEMBERSHIPS) {
1946                         error = ETOOMANYREFS;
1947                         crit_exit();
1948                         break;
1949                 }
1950                 /*
1951                  * Everything looks good; add a new record to the multicast
1952                  * address list for the given interface.
1953                  */
1954                 if ((imo->imo_membership[i] =
1955                      in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
1956                         error = ENOBUFS;
1957                         crit_exit();
1958                         break;
1959                 }
1960                 ++imo->imo_num_memberships;
1961                 crit_exit();
1962                 break;
1963
1964         case IP_DROP_MEMBERSHIP:
1965                 /*
1966                  * Drop a multicast group membership.
1967                  * Group must be a valid IP multicast address.
1968                  */
1969                 error = soopt_to_kbuf(sopt, &mreq, sizeof mreq, sizeof mreq);
1970                 if (error)
1971                         break;
1972
1973                 if (!IN_MULTICAST(ntohl(mreq.imr_multiaddr.s_addr))) {
1974                         error = EINVAL;
1975                         break;
1976                 }
1977
1978                 crit_enter();
1979                 /*
1980                  * If an interface address was specified, get a pointer
1981                  * to its ifnet structure.
1982                  */
1983                 if (mreq.imr_interface.s_addr == INADDR_ANY)
1984                         ifp = NULL;
1985                 else {
1986                         ifp = ip_multicast_if(&mreq.imr_interface, NULL);
1987                         if (ifp == NULL) {
1988                                 error = EADDRNOTAVAIL;
1989                                 crit_exit();
1990                                 break;
1991                         }
1992                 }
1993                 /*
1994                  * Find the membership in the membership array.
1995                  */
1996                 for (i = 0; i < imo->imo_num_memberships; ++i) {
1997                         if ((ifp == NULL ||
1998                              imo->imo_membership[i]->inm_ifp == ifp) &&
1999                             imo->imo_membership[i]->inm_addr.s_addr ==
2000                             mreq.imr_multiaddr.s_addr)
2001                                 break;
2002                 }
2003                 if (i == imo->imo_num_memberships) {
2004                         error = EADDRNOTAVAIL;
2005                         crit_exit();
2006                         break;
2007                 }
2008                 /*
2009                  * Give up the multicast address record to which the
2010                  * membership points.
2011                  */
2012                 in_delmulti(imo->imo_membership[i]);
2013                 /*
2014                  * Remove the gap in the membership array.
2015                  */
2016                 for (++i; i < imo->imo_num_memberships; ++i)
2017                         imo->imo_membership[i-1] = imo->imo_membership[i];
2018                 --imo->imo_num_memberships;
2019                 crit_exit();
2020                 break;
2021
2022         default:
2023                 error = EOPNOTSUPP;
2024                 break;
2025         }
2026
2027         /*
2028          * If all options have default values, no need to keep the mbuf.
2029          */
2030         if (imo->imo_multicast_ifp == NULL &&
2031             imo->imo_multicast_vif == -1 &&
2032             imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
2033             imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
2034             imo->imo_num_memberships == 0) {
2035                 kfree(*imop, M_IPMOPTS);
2036                 *imop = NULL;
2037         }
2038
2039         return (error);
2040 }
2041
2042 /*
2043  * Return the IP multicast options in response to user getsockopt().
2044  */
2045 static int
2046 ip_getmoptions(struct sockopt *sopt, struct ip_moptions *imo)
2047 {
2048         struct in_addr addr;
2049         struct in_ifaddr *ia;
2050         int error, optval;
2051         u_char coptval;
2052
2053         error = 0;
2054         switch (sopt->sopt_name) {
2055         case IP_MULTICAST_VIF:
2056                 if (imo != NULL)
2057                         optval = imo->imo_multicast_vif;
2058                 else
2059                         optval = -1;
2060                 soopt_from_kbuf(sopt, &optval, sizeof optval);
2061                 break;
2062
2063         case IP_MULTICAST_IF:
2064                 if (imo == NULL || imo->imo_multicast_ifp == NULL)
2065                         addr.s_addr = INADDR_ANY;
2066                 else if (imo->imo_multicast_addr.s_addr) {
2067                         /* return the value user has set */
2068                         addr = imo->imo_multicast_addr;
2069                 } else {
2070                         ia = IFP_TO_IA(imo->imo_multicast_ifp);
2071                         addr.s_addr = (ia == NULL) ? INADDR_ANY
2072                                 : IA_SIN(ia)->sin_addr.s_addr;
2073                 }
2074                 soopt_from_kbuf(sopt, &addr, sizeof addr);
2075                 break;
2076
2077         case IP_MULTICAST_TTL:
2078                 if (imo == NULL)
2079                         optval = coptval = IP_DEFAULT_MULTICAST_TTL;
2080                 else
2081                         optval = coptval = imo->imo_multicast_ttl;
2082                 if (sopt->sopt_valsize == 1)
2083                         soopt_from_kbuf(sopt, &coptval, 1);
2084                 else
2085                         soopt_from_kbuf(sopt, &optval, sizeof optval);
2086                 break;
2087
2088         case IP_MULTICAST_LOOP:
2089                 if (imo == NULL)
2090                         optval = coptval = IP_DEFAULT_MULTICAST_LOOP;
2091                 else
2092                         optval = coptval = imo->imo_multicast_loop;
2093                 if (sopt->sopt_valsize == 1)
2094                         soopt_from_kbuf(sopt, &coptval, 1);
2095                 else
2096                         soopt_from_kbuf(sopt, &optval, sizeof optval);
2097                 break;
2098
2099         default:
2100                 error = ENOPROTOOPT;
2101                 break;
2102         }
2103         return (error);
2104 }
2105
2106 /*
2107  * Discard the IP multicast options.
2108  */
2109 void
2110 ip_freemoptions(struct ip_moptions *imo)
2111 {
2112         int i;
2113
2114         if (imo != NULL) {
2115                 for (i = 0; i < imo->imo_num_memberships; ++i)
2116                         in_delmulti(imo->imo_membership[i]);
2117                 kfree(imo, M_IPMOPTS);
2118         }
2119 }
2120
2121 /*
2122  * Routine called from ip_output() to loop back a copy of an IP multicast
2123  * packet to the input queue of a specified interface.  Note that this
2124  * calls the output routine of the loopback "driver", but with an interface
2125  * pointer that might NOT be a loopback interface -- evil, but easier than
2126  * replicating that code here.
2127  */
2128 static void
2129 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
2130              int hlen)
2131 {
2132         struct ip *ip;
2133         struct mbuf *copym;
2134
2135         copym = m_copypacket(m, MB_DONTWAIT);
2136         if (copym != NULL && (copym->m_flags & M_EXT || copym->m_len < hlen))
2137                 copym = m_pullup(copym, hlen);
2138         if (copym != NULL) {
2139                 /*
2140                  * if the checksum hasn't been computed, mark it as valid
2141                  */
2142                 if (copym->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
2143                         in_delayed_cksum(copym);
2144                         copym->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
2145                         copym->m_pkthdr.csum_flags |=
2146                             CSUM_DATA_VALID | CSUM_PSEUDO_HDR;
2147                         copym->m_pkthdr.csum_data = 0xffff;
2148                 }
2149                 /*
2150                  * We don't bother to fragment if the IP length is greater
2151                  * than the interface's MTU.  Can this possibly matter?
2152                  */
2153                 ip = mtod(copym, struct ip *);
2154                 ip->ip_len = htons(ip->ip_len);
2155                 ip->ip_off = htons(ip->ip_off);
2156                 ip->ip_sum = 0;
2157                 if (ip->ip_vhl == IP_VHL_BORING) {
2158                         ip->ip_sum = in_cksum_hdr(ip);
2159                 } else {
2160                         ip->ip_sum = in_cksum(copym, hlen);
2161                 }
2162                 /*
2163                  * NB:
2164                  * It's not clear whether there are any lingering
2165                  * reentrancy problems in other areas which might
2166                  * be exposed by using ip_input directly (in
2167                  * particular, everything which modifies the packet
2168                  * in-place).  Yet another option is using the
2169                  * protosw directly to deliver the looped back
2170                  * packet.  For the moment, we'll err on the side
2171                  * of safety by using if_simloop().
2172                  */
2173 #if 1 /* XXX */
2174                 if (dst->sin_family != AF_INET) {
2175                         kprintf("ip_mloopback: bad address family %d\n",
2176                                                 dst->sin_family);
2177                         dst->sin_family = AF_INET;
2178                 }
2179 #endif
2180                 if_simloop(ifp, copym, dst->sin_family, 0);
2181         }
2182 }