slirp/ip_input.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1988, 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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)ip_input.c  8.2 (Berkeley) 1/4/94
  34  * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
  35  */
  36
  37 /*
  38  * Changes and additions relating to SLiRP are
  39  * Copyright (c) 1995 Danny Gasparovski.
  40  *
  41  * Please read the file COPYRIGHT for the
  42  * terms and conditions of the copyright.
  43  */
  44
  45 #include <slirp.h>
  46 #include "ip_icmp.h"
  47
  48 #ifdef LOG_ENABLED
  49 struct ipstat ipstat;
  50 #endif
  51
  52 struct ipq ipq;
  53
  54 static struct ip *ip_reass(register struct ipasfrag *ip,
  55                            register struct ipq *fp);
  56 static void ip_freef(struct ipq *fp);
  57 static void ip_enq(register struct ipasfrag *p,
  58                    register struct ipasfrag *prev);
  59 static void ip_deq(register struct ipasfrag *p);
  60
  61 /*
  62  * IP initialization: fill in IP protocol switch table.
  63  * All protocols not implemented in kernel go to raw IP protocol handler.
  64  */
  65 void
  66 ip_init()
  67 {
  68         ipq.next = ipq.prev = (ipqp_32)&ipq;
  69         ip_id = tt.tv_sec & 0xffff;
  70         udp_init();
  71         tcp_init();
  72 }
  73
  74 /*
  75  * Ip input routine.  Checksum and byte swap header.  If fragmented
  76  * try to reassemble.  Process options.  Pass to next level.
  77  */
  78 void
  79 ip_input(m)
  80         struct mbuf *m;
  81 {
  82         register struct ip *ip;
  83         int hlen;
  84
  85         DEBUG_CALL("ip_input");
  86         DEBUG_ARG("m = %lx", (long)m);
  87         DEBUG_ARG("m_len = %d", m->m_len);
  88
  89         STAT(ipstat.ips_total++);
  90
  91         if (m->m_len < sizeof (struct ip)) {
  92                 STAT(ipstat.ips_toosmall++);
  93                 return;
  94         }
  95
  96         ip = mtod(m, struct ip *);
  97
  98         if (ip->ip_v != IPVERSION) {
  99                 STAT(ipstat.ips_badvers++);
 100                 goto bad;
 101         }
 102
 103         hlen = ip->ip_hl << 2;
 104         if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
 105           STAT(ipstat.ips_badhlen++);                     /* or packet too short */
 106           goto bad;
 107         }
 108
 109         /* keep ip header intact for ICMP reply
 110          * ip->ip_sum = cksum(m, hlen);
 111          * if (ip->ip_sum) {
 112          */
 113         if(cksum(m,hlen)) {
 114           STAT(ipstat.ips_badsum++);
 115           goto bad;
 116         }
 117
 118         /*
 119          * Convert fields to host representation.
 120          */
 121         NTOHS(ip->ip_len);
 122         if (ip->ip_len < hlen) {
 123                 STAT(ipstat.ips_badlen++);
 124                 goto bad;
 125         }
 126         NTOHS(ip->ip_id);
 127         NTOHS(ip->ip_off);
 128
 129         /*
 130          * Check that the amount of data in the buffers
 131          * is as at least much as the IP header would have us expect.
 132          * Trim mbufs if longer than we expect.
 133          * Drop packet if shorter than we expect.
 134          */
 135         if (m->m_len < ip->ip_len) {
 136                 STAT(ipstat.ips_tooshort++);
 137                 goto bad;
 138         }
 139         /* Should drop packet if mbuf too long? hmmm... */
 140         if (m->m_len > ip->ip_len)
 141            m_adj(m, ip->ip_len - m->m_len);
 142
 143         /* check ip_ttl for a correct ICMP reply */
 144         if(ip->ip_ttl==0 || ip->ip_ttl==1) {
 145           icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
 146           goto bad;
 147         }
 148
 149         /*
 150          * Process options and, if not destined for us,
 151          * ship it on.  ip_dooptions returns 1 when an
 152          * error was detected (causing an icmp message
 153          * to be sent and the original packet to be freed).
 154          */
 155 /* We do no IP options */
 156 /*      if (hlen > sizeof (struct ip) && ip_dooptions(m))
 157  *              goto next;
 158  */
 159         /*
 160          * If offset or IP_MF are set, must reassemble.
 161          * Otherwise, nothing need be done.
 162          * (We could look in the reassembly queue to see
 163          * if the packet was previously fragmented,
 164          * but it's not worth the time; just let them time out.)
 165          *
 166          * XXX This should fail, don't fragment yet
 167          */
 168         if (ip->ip_off &~ IP_DF) {
 169           register struct ipq *fp;
 170                 /*
 171                  * Look for queue of fragments
 172                  * of this datagram.
 173                  */
 174                 for (fp = (struct ipq *) ipq.next; fp != &ipq;
 175                      fp = (struct ipq *) fp->next)
 176                   if (ip->ip_id == fp->ipq_id &&
 177                       ip->ip_src.s_addr == fp->ipq_src.s_addr &&
 178                       ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
 179                       ip->ip_p == fp->ipq_p)
 180                     goto found;
 181                 fp = 0;
 182         found:
 183
 184                 /*
 185                  * Adjust ip_len to not reflect header,
 186                  * set ip_mff if more fragments are expected,
 187                  * convert offset of this to bytes.
 188                  */
 189                 ip->ip_len -= hlen;
 190                 if (ip->ip_off & IP_MF)
 191                   ((struct ipasfrag *)ip)->ipf_mff |= 1;
 192                 else
 193                   ((struct ipasfrag *)ip)->ipf_mff &= ~1;
 194
 195                 ip->ip_off <<= 3;
 196
 197                 /*
 198                  * If datagram marked as having more fragments
 199                  * or if this is not the first fragment,
 200                  * attempt reassembly; if it succeeds, proceed.
 201                  */
 202                 if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) {
 203                         STAT(ipstat.ips_fragments++);
 204                         ip = ip_reass((struct ipasfrag *)ip, fp);
 205                         if (ip == 0)
 206                                 return;
 207                         STAT(ipstat.ips_reassembled++);
 208                         m = dtom(ip);
 209                 } else
 210                         if (fp)
 211                            ip_freef(fp);
 212
 213         } else
 214                 ip->ip_len -= hlen;
 215
 216         /*
 217          * Switch out to protocol's input routine.
 218          */
 219         STAT(ipstat.ips_delivered++);
 220         switch (ip->ip_p) {
 221          case IPPROTO_TCP:
 222                 tcp_input(m, hlen, (struct socket *)NULL);
 223                 break;
 224          case IPPROTO_UDP:
 225                 udp_input(m, hlen);
 226                 break;
 227          case IPPROTO_ICMP:
 228                 icmp_input(m, hlen);
 229                 break;
 230          default:
 231                 STAT(ipstat.ips_noproto++);
 232                 m_free(m);
 233         }
 234         return;
 235 bad:
 236         m_freem(m);
 237         return;
 238 }
 239
 240 /*
 241  * Take incoming datagram fragment and try to
 242  * reassemble it into whole datagram.  If a chain for
 243  * reassembly of this datagram already exists, then it
 244  * is given as fp; otherwise have to make a chain.
 245  */
 246 static struct ip *
 247 ip_reass(register struct ipasfrag *ip, register struct ipq *fp)
 248 {
 249         register struct mbuf *m = dtom(ip);
 250         register struct ipasfrag *q;
 251         int hlen = ip->ip_hl << 2;
 252         int i, next;
 253
 254         DEBUG_CALL("ip_reass");
 255         DEBUG_ARG("ip = %lx", (long)ip);
 256         DEBUG_ARG("fp = %lx", (long)fp);
 257         DEBUG_ARG("m = %lx", (long)m);
 258
 259         /*
 260          * Presence of header sizes in mbufs
 261          * would confuse code below.
 262          * Fragment m_data is concatenated.
 263          */
 264         m->m_data += hlen;
 265         m->m_len -= hlen;
 266
 267         /*
 268          * If first fragment to arrive, create a reassembly queue.
 269          */
 270         if (fp == 0) {
 271           struct mbuf *t;
 272           if ((t = m_get()) == NULL) goto dropfrag;
 273           fp = mtod(t, struct ipq *);
 274           insque_32(fp, &ipq);
 275           fp->ipq_ttl = IPFRAGTTL;
 276           fp->ipq_p = ip->ip_p;
 277           fp->ipq_id = ip->ip_id;
 278           fp->ipq_next = fp->ipq_prev = (ipasfragp_32)fp;
 279           fp->ipq_src = ((struct ip *)ip)->ip_src;
 280           fp->ipq_dst = ((struct ip *)ip)->ip_dst;
 281           q = (struct ipasfrag *)fp;
 282           goto insert;
 283         }
 284
 285         /*
 286          * Find a segment which begins after this one does.
 287          */
 288         for (q = (struct ipasfrag *)fp->ipq_next; q != (struct ipasfrag *)fp;
 289             q = (struct ipasfrag *)q->ipf_next)
 290                 if (q->ip_off > ip->ip_off)
 291                         break;
 292
 293         /*
 294          * If there is a preceding segment, it may provide some of
 295          * our data already.  If so, drop the data from the incoming
 296          * segment.  If it provides all of our data, drop us.
 297          */
 298         if (q->ipf_prev != (ipasfragp_32)fp) {
 299                 i = ((struct ipasfrag *)(q->ipf_prev))->ip_off +
 300                   ((struct ipasfrag *)(q->ipf_prev))->ip_len - ip->ip_off;
 301                 if (i > 0) {
 302                         if (i >= ip->ip_len)
 303                                 goto dropfrag;
 304                         m_adj(dtom(ip), i);
 305                         ip->ip_off += i;
 306                         ip->ip_len -= i;
 307                 }
 308         }
 309
 310         /*
 311          * While we overlap succeeding segments trim them or,
 312          * if they are completely covered, dequeue them.
 313          */
 314         while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) {
 315                 i = (ip->ip_off + ip->ip_len) - q->ip_off;
 316                 if (i < q->ip_len) {
 317                         q->ip_len -= i;
 318                         q->ip_off += i;
 319                         m_adj(dtom(q), i);
 320                         break;
 321                 }
 322                 q = (struct ipasfrag *) q->ipf_next;
 323                 m_freem(dtom((struct ipasfrag *) q->ipf_prev));
 324                 ip_deq((struct ipasfrag *) q->ipf_prev);
 325         }
 326
 327 insert:
 328         /*
 329          * Stick new segment in its place;
 330          * check for complete reassembly.
 331          */
 332         ip_enq(ip, (struct ipasfrag *) q->ipf_prev);
 333         next = 0;
 334         for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp;
 335              q = (struct ipasfrag *) q->ipf_next) {
 336                 if (q->ip_off != next)
 337                         return (0);
 338                 next += q->ip_len;
 339         }
 340         if (((struct ipasfrag *)(q->ipf_prev))->ipf_mff & 1)
 341                 return (0);
 342
 343         /*
 344          * Reassembly is complete; concatenate fragments.
 345          */
 346         q = (struct ipasfrag *) fp->ipq_next;
 347         m = dtom(q);
 348
 349         q = (struct ipasfrag *) q->ipf_next;
 350         while (q != (struct ipasfrag *)fp) {
 351           struct mbuf *t;
 352           t = dtom(q);
 353           q = (struct ipasfrag *) q->ipf_next;
 354           m_cat(m, t);
 355         }
 356
 357         /*
 358          * Create header for new ip packet by
 359          * modifying header of first packet;
 360          * dequeue and discard fragment reassembly header.
 361          * Make header visible.
 362          */
 363         ip = (struct ipasfrag *) fp->ipq_next;
 364
 365         /*
 366          * If the fragments concatenated to an mbuf that's
 367          * bigger than the total size of the fragment, then and
 368          * m_ext buffer was alloced. But fp->ipq_next points to
 369          * the old buffer (in the mbuf), so we must point ip
 370          * into the new buffer.
 371          */
 372         if (m->m_flags & M_EXT) {
 373           int delta;
 374           delta = (char *)ip - m->m_dat;
 375           ip = (struct ipasfrag *)(m->m_ext + delta);
 376         }
 377
 378         /* DEBUG_ARG("ip = %lx", (long)ip);
 379          * ip=(struct ipasfrag *)m->m_data; */
 380
 381         ip->ip_len = next;
 382         ip->ipf_mff &= ~1;
 383         ((struct ip *)ip)->ip_src = fp->ipq_src;
 384         ((struct ip *)ip)->ip_dst = fp->ipq_dst;
 385         remque_32(fp);
 386         (void) m_free(dtom(fp));
 387         m = dtom(ip);
 388         m->m_len += (ip->ip_hl << 2);
 389         m->m_data -= (ip->ip_hl << 2);
 390
 391         return ((struct ip *)ip);
 392
 393 dropfrag:
 394         STAT(ipstat.ips_fragdropped++);
 395         m_freem(m);
 396         return (0);
 397 }
 398
 399 /*
 400  * Free a fragment reassembly header and all
 401  * associated datagrams.
 402  */
 403 static void
 404 ip_freef(struct ipq *fp)
 405 {
 406         register struct ipasfrag *q, *p;
 407
 408         for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp;
 409             q = p) {
 410                 p = (struct ipasfrag *) q->ipf_next;
 411                 ip_deq(q);
 412                 m_freem(dtom(q));
 413         }
 414         remque_32(fp);
 415         (void) m_free(dtom(fp));
 416 }
 417
 418 /*
 419  * Put an ip fragment on a reassembly chain.
 420  * Like insque, but pointers in middle of structure.
 421  */
 422 static void
 423 ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)
 424 {
 425         DEBUG_CALL("ip_enq");
 426         DEBUG_ARG("prev = %lx", (long)prev);
 427         p->ipf_prev = (ipasfragp_32) prev;
 428         p->ipf_next = prev->ipf_next;
 429         ((struct ipasfrag *)(prev->ipf_next))->ipf_prev = (ipasfragp_32) p;
 430         prev->ipf_next = (ipasfragp_32) p;
 431 }
 432
 433 /*
 434  * To ip_enq as remque is to insque.
 435  */
 436 static void
 437 ip_deq(register struct ipasfrag *p)
 438 {
 439         ((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
 440         ((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
 441 }
 442
 443 /*
 444  * IP timer processing;
 445  * if a timer expires on a reassembly
 446  * queue, discard it.
 447  */
 448 void
 449 ip_slowtimo()
 450 {
 451         register struct ipq *fp;
 452
 453         DEBUG_CALL("ip_slowtimo");
 454
 455         fp = (struct ipq *) ipq.next;
 456         if (fp == 0)
 457            return;
 458
 459         while (fp != &ipq) {
 460                 --fp->ipq_ttl;
 461                 fp = (struct ipq *) fp->next;
 462                 if (((struct ipq *)(fp->prev))->ipq_ttl == 0) {
 463                         STAT(ipstat.ips_fragtimeout++);
 464                         ip_freef((struct ipq *) fp->prev);
 465                 }
 466         }
 467 }
 468
 469 /*
 470  * Do option processing on a datagram,
 471  * possibly discarding it if bad options are encountered,
 472  * or forwarding it if source-routed.
 473  * Returns 1 if packet has been forwarded/freed,
 474  * 0 if the packet should be processed further.
 475  */
 476
 477 #ifdef notdef
 478
 479 int
 480 ip_dooptions(m)
 481         struct mbuf *m;
 482 {
 483         register struct ip *ip = mtod(m, struct ip *);
 484         register u_char *cp;
 485         register struct ip_timestamp *ipt;
 486         register struct in_ifaddr *ia;
 487 /*      int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; */
 488         int opt, optlen, cnt, off, code, type, forward = 0;
 489         struct in_addr *sin, dst;
 490 typedef u_int32_t n_time;
 491         n_time ntime;
 492
 493         dst = ip->ip_dst;
 494         cp = (u_char *)(ip + 1);
 495         cnt = (ip->ip_hl << 2) - sizeof (struct ip);
 496         for (; cnt > 0; cnt -= optlen, cp += optlen) {
 497                 opt = cp[IPOPT_OPTVAL];
 498                 if (opt == IPOPT_EOL)
 499                         break;
 500                 if (opt == IPOPT_NOP)
 501                         optlen = 1;
 502                 else {
 503                         optlen = cp[IPOPT_OLEN];
 504                         if (optlen <= 0 || optlen > cnt) {
 505                                 code = &cp[IPOPT_OLEN] - (u_char *)ip;
 506                                 goto bad;
 507                         }
 508                 }
 509                 switch (opt) {
 510
 511                 default:
 512                         break;
 513
 514                 /*
 515                  * Source routing with record.
 516                  * Find interface with current destination address.
 517                  * If none on this machine then drop if strictly routed,
 518                  * or do nothing if loosely routed.
 519                  * Record interface address and bring up next address
 520                  * component.  If strictly routed make sure next
 521                  * address is on directly accessible net.
 522                  */
 523                 case IPOPT_LSRR:
 524                 case IPOPT_SSRR:
 525                         if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
 526                                 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
 527                                 goto bad;
 528                         }
 529                         ipaddr.sin_addr = ip->ip_dst;
 530                         ia = (struct in_ifaddr *)
 531                                 ifa_ifwithaddr((struct sockaddr *)&ipaddr);
 532                         if (ia == 0) {
 533                                 if (opt == IPOPT_SSRR) {
 534                                         type = ICMP_UNREACH;
 535                                         code = ICMP_UNREACH_SRCFAIL;
 536                                         goto bad;
 537                                 }
 538                                 /*
 539                                  * Loose routing, and not at next destination
 540                                  * yet; nothing to do except forward.
 541                                  */
 542                                 break;
 543                         }
 544                         off--;                  / * 0 origin *  /
 545                         if (off > optlen - sizeof(struct in_addr)) {
 546                                 /*
 547                                  * End of source route.  Should be for us.
 548                                  */
 549                                 save_rte(cp, ip->ip_src);
 550                                 break;
 551                         }
 552                         /*
 553                          * locate outgoing interface
 554                          */
 555                         bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
 556                             sizeof(ipaddr.sin_addr));
 557                         if (opt == IPOPT_SSRR) {
 558 #define INA     struct in_ifaddr *
 559 #define SA      struct sockaddr *
 560                             if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
 561                                 ia = (INA)ifa_ifwithnet((SA)&ipaddr);
 562                         } else
 563                                 ia = ip_rtaddr(ipaddr.sin_addr);
 564                         if (ia == 0) {
 565                                 type = ICMP_UNREACH;
 566                                 code = ICMP_UNREACH_SRCFAIL;
 567                                 goto bad;
 568                         }
 569                         ip->ip_dst = ipaddr.sin_addr;
 570                         bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
 571                             (caddr_t)(cp + off), sizeof(struct in_addr));
 572                         cp[IPOPT_OFFSET] += sizeof(struct in_addr);
 573                         /*
 574                          * Let ip_intr's mcast routing check handle mcast pkts
 575                          */
 576                         forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
 577                         break;
 578
 579                 case IPOPT_RR:
 580                         if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
 581                                 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
 582                                 goto bad;
 583                         }
 584                         /*
 585                          * If no space remains, ignore.
 586                          */
 587                         off--;                   * 0 origin *
 588                         if (off > optlen - sizeof(struct in_addr))
 589                                 break;
 590                         bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
 591                             sizeof(ipaddr.sin_addr));
 592                         /*
 593                          * locate outgoing interface; if we're the destination,
 594                          * use the incoming interface (should be same).
 595                          */
 596                         if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
 597                             (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
 598                                 type = ICMP_UNREACH;
 599                                 code = ICMP_UNREACH_HOST;
 600                                 goto bad;
 601                         }
 602                         bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
 603                             (caddr_t)(cp + off), sizeof(struct in_addr));
 604                         cp[IPOPT_OFFSET] += sizeof(struct in_addr);
 605                         break;
 606
 607                 case IPOPT_TS:
 608                         code = cp - (u_char *)ip;
 609                         ipt = (struct ip_timestamp *)cp;
 610                         if (ipt->ipt_len < 5)
 611                                 goto bad;
 612                         if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
 613                                 if (++ipt->ipt_oflw == 0)
 614                                         goto bad;
 615                                 break;
 616                         }
 617                         sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
 618                         switch (ipt->ipt_flg) {
 619
 620                         case IPOPT_TS_TSONLY:
 621                                 break;
 622
 623                         case IPOPT_TS_TSANDADDR:
 624                                 if (ipt->ipt_ptr + sizeof(n_time) +
 625                                     sizeof(struct in_addr) > ipt->ipt_len)
 626                                         goto bad;
 627                                 ipaddr.sin_addr = dst;
 628                                 ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,
 629                                                             m->m_pkthdr.rcvif);
 630                                 if (ia == 0)
 631                                         continue;
 632                                 bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
 633                                     (caddr_t)sin, sizeof(struct in_addr));
 634                                 ipt->ipt_ptr += sizeof(struct in_addr);
 635                                 break;
 636
 637                         case IPOPT_TS_PRESPEC:
 638                                 if (ipt->ipt_ptr + sizeof(n_time) +
 639                                     sizeof(struct in_addr) > ipt->ipt_len)
 640                                         goto bad;
 641                                 bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
 642                                     sizeof(struct in_addr));
 643                                 if (ifa_ifwithaddr((SA)&ipaddr) == 0)
 644                                         continue;
 645                                 ipt->ipt_ptr += sizeof(struct in_addr);
 646                                 break;
 647
 648                         default:
 649                                 goto bad;
 650                         }
 651                         ntime = iptime();
 652                         bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
 653                             sizeof(n_time));
 654                         ipt->ipt_ptr += sizeof(n_time);
 655                 }
 656         }
 657         if (forward) {
 658                 ip_forward(m, 1);
 659                 return (1);
 660         }
 661                 }
 662         }
 663         return (0);
 664 bad:
 665         /* ip->ip_len -= ip->ip_hl << 2;   XXX icmp_error adds in hdr length */
 666
 667 /* Not yet */
 668         icmp_error(m, type, code, 0, 0);
 669
 670         STAT(ipstat.ips_badoptions++);
 671         return (1);
 672 }
 673
 674 #endif /* notdef */
 675
 676 /*
 677  * Strip out IP options, at higher
 678  * level protocol in the kernel.
 679  * Second argument is buffer to which options
 680  * will be moved, and return value is their length.
 681  * (XXX) should be deleted; last arg currently ignored.
 682  */
 683 void
 684 ip_stripoptions(m, mopt)
 685         register struct mbuf *m;
 686         struct mbuf *mopt;
 687 {
 688         register int i;
 689         struct ip *ip = mtod(m, struct ip *);
 690         register caddr_t opts;
 691         int olen;
 692
 693         olen = (ip->ip_hl<<2) - sizeof (struct ip);
 694         opts = (caddr_t)(ip + 1);
 695         i = m->m_len - (sizeof (struct ip) + olen);
 696         memcpy(opts, opts  + olen, (unsigned)i);
 697         m->m_len -= olen;
 698
 699         ip->ip_hl = sizeof(struct ip) >> 2;
 700 }