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. 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_input.c  8.2 (Berkeley) 1/4/94
  30  * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
  31  */
  32
  33 /*
  34  * Changes and additions relating to SLiRP are
  35  * Copyright (c) 1995 Danny Gasparovski.
  36  *
  37  * Please read the file COPYRIGHT for the
  38  * terms and conditions of the copyright.
  39  */
  40
  41 #include <slirp.h>
  42 #include <osdep.h>
  43 #include "ip_icmp.h"
  44
  45 static struct ip *ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp);
  46 static void ip_freef(Slirp *slirp, struct ipq *fp);
  47 static void ip_enq(register struct ipasfrag *p,
  48                    register struct ipasfrag *prev);
  49 static void ip_deq(register struct ipasfrag *p);
  50
  51 /*
  52  * IP initialization: fill in IP protocol switch table.
  53  * All protocols not implemented in kernel go to raw IP protocol handler.
  54  */
  55 void
  56 ip_init(Slirp *slirp)
  57 {
  58     slirp->ipq.ip_link.next = slirp->ipq.ip_link.prev = &slirp->ipq.ip_link;
  59     udp_init(slirp);
  60     tcp_init(slirp);
  61 }
  62
  63 /*
  64  * Ip input routine.  Checksum and byte swap header.  If fragmented
  65  * try to reassemble.  Process options.  Pass to next level.
  66  */
  67 void
  68 ip_input(struct mbuf *m)
  69 {
  70         Slirp *slirp = m->slirp;
  71         register struct ip *ip;
  72         int hlen;
  73
  74         DEBUG_CALL("ip_input");
  75         DEBUG_ARG("m = %lx", (long)m);
  76         DEBUG_ARG("m_len = %d", m->m_len);
  77
  78         if (m->m_len < sizeof (struct ip)) {
  79                 return;
  80         }
  81
  82         ip = mtod(m, struct ip *);
  83
  84         if (ip->ip_v != IPVERSION) {
  85                 goto bad;
  86         }
  87
  88         hlen = ip->ip_hl << 2;
  89         if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
  90           goto bad;                                  /* or packet too short */
  91         }
  92
  93         /* keep ip header intact for ICMP reply
  94          * ip->ip_sum = cksum(m, hlen);
  95          * if (ip->ip_sum) {
  96          */
  97         if(cksum(m,hlen)) {
  98           goto bad;
  99         }
 100
 101         /*
 102          * Convert fields to host representation.
 103          */
 104         NTOHS(ip->ip_len);
 105         if (ip->ip_len < hlen) {
 106                 goto bad;
 107         }
 108         NTOHS(ip->ip_id);
 109         NTOHS(ip->ip_off);
 110
 111         /*
 112          * Check that the amount of data in the buffers
 113          * is as at least much as the IP header would have us expect.
 114          * Trim mbufs if longer than we expect.
 115          * Drop packet if shorter than we expect.
 116          */
 117         if (m->m_len < ip->ip_len) {
 118                 goto bad;
 119         }
 120
 121     if (slirp->restricted) {
 122         if ((ip->ip_dst.s_addr & slirp->vnetwork_mask.s_addr) ==
 123             slirp->vnetwork_addr.s_addr) {
 124             if (ip->ip_dst.s_addr == 0xffffffff && ip->ip_p != IPPROTO_UDP)
 125                 goto bad;
 126         } else {
 127             uint32_t inv_mask = ~slirp->vnetwork_mask.s_addr;
 128             struct ex_list *ex_ptr;
 129
 130             if ((ip->ip_dst.s_addr & inv_mask) == inv_mask) {
 131                 goto bad;
 132             }
 133             for (ex_ptr = slirp->exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next)
 134                 if (ex_ptr->ex_addr.s_addr == ip->ip_dst.s_addr)
 135                     break;
 136
 137             if (!ex_ptr)
 138                 goto bad;
 139         }
 140     }
 141
 142         /* Should drop packet if mbuf too long? hmmm... */
 143         if (m->m_len > ip->ip_len)
 144            m_adj(m, ip->ip_len - m->m_len);
 145
 146         /* check ip_ttl for a correct ICMP reply */
 147         if(ip->ip_ttl==0) {
 148           icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
 149           goto bad;
 150         }
 151
 152         /*
 153          * If offset or IP_MF are set, must reassemble.
 154          * Otherwise, nothing need be done.
 155          * (We could look in the reassembly queue to see
 156          * if the packet was previously fragmented,
 157          * but it's not worth the time; just let them time out.)
 158          *
 159          * XXX This should fail, don't fragment yet
 160          */
 161         if (ip->ip_off &~ IP_DF) {
 162           register struct ipq *fp;
 163       struct qlink *l;
 164                 /*
 165                  * Look for queue of fragments
 166                  * of this datagram.
 167                  */
 168                 for (l = slirp->ipq.ip_link.next; l != &slirp->ipq.ip_link;
 169                      l = l->next) {
 170             fp = container_of(l, struct ipq, ip_link);
 171             if (ip->ip_id == fp->ipq_id &&
 172                     ip->ip_src.s_addr == fp->ipq_src.s_addr &&
 173                     ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
 174                     ip->ip_p == fp->ipq_p)
 175                     goto found;
 176         }
 177         fp = NULL;
 178         found:
 179
 180                 /*
 181                  * Adjust ip_len to not reflect header,
 182                  * set ip_mff if more fragments are expected,
 183                  * convert offset of this to bytes.
 184                  */
 185                 ip->ip_len -= hlen;
 186                 if (ip->ip_off & IP_MF)
 187                   ip->ip_tos |= 1;
 188                 else
 189                   ip->ip_tos &= ~1;
 190
 191                 ip->ip_off <<= 3;
 192
 193                 /*
 194                  * If datagram marked as having more fragments
 195                  * or if this is not the first fragment,
 196                  * attempt reassembly; if it succeeds, proceed.
 197                  */
 198                 if (ip->ip_tos & 1 || ip->ip_off) {
 199                         ip = ip_reass(slirp, ip, fp);
 200                         if (ip == NULL)
 201                                 return;
 202                         m = dtom(slirp, ip);
 203                 } else
 204                         if (fp)
 205                            ip_freef(slirp, fp);
 206
 207         } else
 208                 ip->ip_len -= hlen;
 209
 210         /*
 211          * Switch out to protocol's input routine.
 212          */
 213         switch (ip->ip_p) {
 214          case IPPROTO_TCP:
 215                 tcp_input(m, hlen, (struct socket *)NULL);
 216                 break;
 217          case IPPROTO_UDP:
 218                 udp_input(m, hlen);
 219                 break;
 220          case IPPROTO_ICMP:
 221                 icmp_input(m, hlen);
 222                 break;
 223          default:
 224                 m_free(m);
 225         }
 226         return;
 227 bad:
 228         m_freem(m);
 229         return;
 230 }
 231
 232 #define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
 233 #define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))
 234 /*
 235  * Take incoming datagram fragment and try to
 236  * reassemble it into whole datagram.  If a chain for
 237  * reassembly of this datagram already exists, then it
 238  * is given as fp; otherwise have to make a chain.
 239  */
 240 static struct ip *
 241 ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp)
 242 {
 243         register struct mbuf *m = dtom(slirp, ip);
 244         register struct ipasfrag *q;
 245         int hlen = ip->ip_hl << 2;
 246         int i, next;
 247
 248         DEBUG_CALL("ip_reass");
 249         DEBUG_ARG("ip = %lx", (long)ip);
 250         DEBUG_ARG("fp = %lx", (long)fp);
 251         DEBUG_ARG("m = %lx", (long)m);
 252
 253         /*
 254          * Presence of header sizes in mbufs
 255          * would confuse code below.
 256          * Fragment m_data is concatenated.
 257          */
 258         m->m_data += hlen;
 259         m->m_len -= hlen;
 260
 261         /*
 262          * If first fragment to arrive, create a reassembly queue.
 263          */
 264         if (fp == NULL) {
 265           struct mbuf *t = m_get(slirp);
 266
 267           if (t == NULL) {
 268               goto dropfrag;
 269           }
 270           fp = mtod(t, struct ipq *);
 271           insque(&fp->ip_link, &slirp->ipq.ip_link);
 272           fp->ipq_ttl = IPFRAGTTL;
 273           fp->ipq_p = ip->ip_p;
 274           fp->ipq_id = ip->ip_id;
 275           fp->frag_link.next = fp->frag_link.prev = &fp->frag_link;
 276           fp->ipq_src = ip->ip_src;
 277           fp->ipq_dst = ip->ip_dst;
 278           q = (struct ipasfrag *)fp;
 279           goto insert;
 280         }
 281
 282         /*
 283          * Find a segment which begins after this one does.
 284          */
 285         for (q = fp->frag_link.next; q != (struct ipasfrag *)&fp->frag_link;
 286             q = q->ipf_next)
 287                 if (q->ipf_off > ip->ip_off)
 288                         break;
 289
 290         /*
 291          * If there is a preceding segment, it may provide some of
 292          * our data already.  If so, drop the data from the incoming
 293          * segment.  If it provides all of our data, drop us.
 294          */
 295         if (q->ipf_prev != &fp->frag_link) {
 296         struct ipasfrag *pq = q->ipf_prev;
 297                 i = pq->ipf_off + pq->ipf_len - ip->ip_off;
 298                 if (i > 0) {
 299                         if (i >= ip->ip_len)
 300                                 goto dropfrag;
 301                         m_adj(dtom(slirp, ip), i);
 302                         ip->ip_off += i;
 303                         ip->ip_len -= i;
 304                 }
 305         }
 306
 307         /*
 308          * While we overlap succeeding segments trim them or,
 309          * if they are completely covered, dequeue them.
 310          */
 311         while (q != (struct ipasfrag*)&fp->frag_link &&
 312             ip->ip_off + ip->ip_len > q->ipf_off) {
 313                 i = (ip->ip_off + ip->ip_len) - q->ipf_off;
 314                 if (i < q->ipf_len) {
 315                         q->ipf_len -= i;
 316                         q->ipf_off += i;
 317                         m_adj(dtom(slirp, q), i);
 318                         break;
 319                 }
 320                 q = q->ipf_next;
 321                 m_freem(dtom(slirp, q->ipf_prev));
 322                 ip_deq(q->ipf_prev);
 323         }
 324
 325 insert:
 326         /*
 327          * Stick new segment in its place;
 328          * check for complete reassembly.
 329          */
 330         ip_enq(iptofrag(ip), q->ipf_prev);
 331         next = 0;
 332         for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link;
 333             q = q->ipf_next) {
 334                 if (q->ipf_off != next)
 335                         return NULL;
 336                 next += q->ipf_len;
 337         }
 338         if (((struct ipasfrag *)(q->ipf_prev))->ipf_tos & 1)
 339                 return NULL;
 340
 341         /*
 342          * Reassembly is complete; concatenate fragments.
 343          */
 344     q = fp->frag_link.next;
 345         m = dtom(slirp, q);
 346
 347         q = (struct ipasfrag *) q->ipf_next;
 348         while (q != (struct ipasfrag*)&fp->frag_link) {
 349           struct mbuf *t = dtom(slirp, q);
 350           q = (struct ipasfrag *) q->ipf_next;
 351           m_cat(m, t);
 352         }
 353
 354         /*
 355          * Create header for new ip packet by
 356          * modifying header of first packet;
 357          * dequeue and discard fragment reassembly header.
 358          * Make header visible.
 359          */
 360         q = fp->frag_link.next;
 361
 362         /*
 363          * If the fragments concatenated to an mbuf that's
 364          * bigger than the total size of the fragment, then and
 365          * m_ext buffer was alloced. But fp->ipq_next points to
 366          * the old buffer (in the mbuf), so we must point ip
 367          * into the new buffer.
 368          */
 369         if (m->m_flags & M_EXT) {
 370           int delta = (char *)q - m->m_dat;
 371           q = (struct ipasfrag *)(m->m_ext + delta);
 372         }
 373
 374     ip = fragtoip(q);
 375         ip->ip_len = next;
 376         ip->ip_tos &= ~1;
 377         ip->ip_src = fp->ipq_src;
 378         ip->ip_dst = fp->ipq_dst;
 379         remque(&fp->ip_link);
 380         (void) m_free(dtom(slirp, fp));
 381         m->m_len += (ip->ip_hl << 2);
 382         m->m_data -= (ip->ip_hl << 2);
 383
 384         return ip;
 385
 386 dropfrag:
 387         m_freem(m);
 388         return NULL;
 389 }
 390
 391 /*
 392  * Free a fragment reassembly header and all
 393  * associated datagrams.
 394  */
 395 static void
 396 ip_freef(Slirp *slirp, struct ipq *fp)
 397 {
 398         register struct ipasfrag *q, *p;
 399
 400         for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link; q = p) {
 401                 p = q->ipf_next;
 402                 ip_deq(q);
 403                 m_freem(dtom(slirp, q));
 404         }
 405         remque(&fp->ip_link);
 406         (void) m_free(dtom(slirp, fp));
 407 }
 408
 409 /*
 410  * Put an ip fragment on a reassembly chain.
 411  * Like insque, but pointers in middle of structure.
 412  */
 413 static void
 414 ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)
 415 {
 416         DEBUG_CALL("ip_enq");
 417         DEBUG_ARG("prev = %lx", (long)prev);
 418         p->ipf_prev =  prev;
 419         p->ipf_next = prev->ipf_next;
 420         ((struct ipasfrag *)(prev->ipf_next))->ipf_prev = p;
 421         prev->ipf_next = p;
 422 }
 423
 424 /*
 425  * To ip_enq as remque is to insque.
 426  */
 427 static void
 428 ip_deq(register struct ipasfrag *p)
 429 {
 430         ((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
 431         ((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
 432 }
 433
 434 /*
 435  * IP timer processing;
 436  * if a timer expires on a reassembly
 437  * queue, discard it.
 438  */
 439 void
 440 ip_slowtimo(Slirp *slirp)
 441 {
 442     struct qlink *l;
 443
 444         DEBUG_CALL("ip_slowtimo");
 445
 446     l = slirp->ipq.ip_link.next;
 447
 448         if (l == NULL)
 449            return;
 450
 451     while (l != &slirp->ipq.ip_link) {
 452         struct ipq *fp = container_of(l, struct ipq, ip_link);
 453         l = l->next;
 454                 if (--fp->ipq_ttl == 0) {
 455                         ip_freef(slirp, fp);
 456                 }
 457     }
 458 }
 459
 460 /*
 461  * Do option processing on a datagram,
 462  * possibly discarding it if bad options are encountered,
 463  * or forwarding it if source-routed.
 464  * Returns 1 if packet has been forwarded/freed,
 465  * 0 if the packet should be processed further.
 466  */
 467
 468 #ifdef notdef
 469
 470 int
 471 ip_dooptions(m)
 472         struct mbuf *m;
 473 {
 474         register struct ip *ip = mtod(m, struct ip *);
 475         register u_char *cp;
 476         register struct ip_timestamp *ipt;
 477         register struct in_ifaddr *ia;
 478         int opt, optlen, cnt, off, code, type, forward = 0;
 479         struct in_addr *sin, dst;
 480 typedef uint32_t n_time;
 481         n_time ntime;
 482
 483         dst = ip->ip_dst;
 484         cp = (u_char *)(ip + 1);
 485         cnt = (ip->ip_hl << 2) - sizeof (struct ip);
 486         for (; cnt > 0; cnt -= optlen, cp += optlen) {
 487                 opt = cp[IPOPT_OPTVAL];
 488                 if (opt == IPOPT_EOL)
 489                         break;
 490                 if (opt == IPOPT_NOP)
 491                         optlen = 1;
 492                 else {
 493                         optlen = cp[IPOPT_OLEN];
 494                         if (optlen <= 0 || optlen > cnt) {
 495                                 code = &cp[IPOPT_OLEN] - (u_char *)ip;
 496                                 goto bad;
 497                         }
 498                 }
 499                 switch (opt) {
 500
 501                 default:
 502                         break;
 503
 504                 /*
 505                  * Source routing with record.
 506                  * Find interface with current destination address.
 507                  * If none on this machine then drop if strictly routed,
 508                  * or do nothing if loosely routed.
 509                  * Record interface address and bring up next address
 510                  * component.  If strictly routed make sure next
 511                  * address is on directly accessible net.
 512                  */
 513                 case IPOPT_LSRR:
 514                 case IPOPT_SSRR:
 515                         if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
 516                                 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
 517                                 goto bad;
 518                         }
 519                         ipaddr.sin_addr = ip->ip_dst;
 520                         ia = (struct in_ifaddr *)
 521                                 ifa_ifwithaddr((struct sockaddr *)&ipaddr);
 522                         if (ia == 0) {
 523                                 if (opt == IPOPT_SSRR) {
 524                                         type = ICMP_UNREACH;
 525                                         code = ICMP_UNREACH_SRCFAIL;
 526                                         goto bad;
 527                                 }
 528                                 /*
 529                                  * Loose routing, and not at next destination
 530                                  * yet; nothing to do except forward.
 531                                  */
 532                                 break;
 533                         }
 534                         off--;                  / * 0 origin *  /
 535                         if (off > optlen - sizeof(struct in_addr)) {
 536                                 /*
 537                                  * End of source route.  Should be for us.
 538                                  */
 539                                 save_rte(cp, ip->ip_src);
 540                                 break;
 541                         }
 542                         /*
 543                          * locate outgoing interface
 544                          */
 545                         bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
 546                             sizeof(ipaddr.sin_addr));
 547                         if (opt == IPOPT_SSRR) {
 548 #define INA     struct in_ifaddr *
 549 #define SA      struct sockaddr *
 550                             if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
 551                                 ia = (INA)ifa_ifwithnet((SA)&ipaddr);
 552                         } else
 553                                 ia = ip_rtaddr(ipaddr.sin_addr);
 554                         if (ia == 0) {
 555                                 type = ICMP_UNREACH;
 556                                 code = ICMP_UNREACH_SRCFAIL;
 557                                 goto bad;
 558                         }
 559                         ip->ip_dst = ipaddr.sin_addr;
 560                         bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
 561                             (caddr_t)(cp + off), sizeof(struct in_addr));
 562                         cp[IPOPT_OFFSET] += sizeof(struct in_addr);
 563                         /*
 564                          * Let ip_intr's mcast routing check handle mcast pkts
 565                          */
 566                         forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
 567                         break;
 568
 569                 case IPOPT_RR:
 570                         if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
 571                                 code = &cp[IPOPT_OFFSET] - (u_char *)ip;
 572                                 goto bad;
 573                         }
 574                         /*
 575                          * If no space remains, ignore.
 576                          */
 577                         off--;                   * 0 origin *
 578                         if (off > optlen - sizeof(struct in_addr))
 579                                 break;
 580                         bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
 581                             sizeof(ipaddr.sin_addr));
 582                         /*
 583                          * locate outgoing interface; if we're the destination,
 584                          * use the incoming interface (should be same).
 585                          */
 586                         if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
 587                             (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
 588                                 type = ICMP_UNREACH;
 589                                 code = ICMP_UNREACH_HOST;
 590                                 goto bad;
 591                         }
 592                         bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
 593                             (caddr_t)(cp + off), sizeof(struct in_addr));
 594                         cp[IPOPT_OFFSET] += sizeof(struct in_addr);
 595                         break;
 596
 597                 case IPOPT_TS:
 598                         code = cp - (u_char *)ip;
 599                         ipt = (struct ip_timestamp *)cp;
 600                         if (ipt->ipt_len < 5)
 601                                 goto bad;
 602                         if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
 603                                 if (++ipt->ipt_oflw == 0)
 604                                         goto bad;
 605                                 break;
 606                         }
 607                         sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
 608                         switch (ipt->ipt_flg) {
 609
 610                         case IPOPT_TS_TSONLY:
 611                                 break;
 612
 613                         case IPOPT_TS_TSANDADDR:
 614                                 if (ipt->ipt_ptr + sizeof(n_time) +
 615                                     sizeof(struct in_addr) > ipt->ipt_len)
 616                                         goto bad;
 617                                 ipaddr.sin_addr = dst;
 618                                 ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,
 619                                                             m->m_pkthdr.rcvif);
 620                                 if (ia == 0)
 621                                         continue;
 622                                 bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
 623                                     (caddr_t)sin, sizeof(struct in_addr));
 624                                 ipt->ipt_ptr += sizeof(struct in_addr);
 625                                 break;
 626
 627                         case IPOPT_TS_PRESPEC:
 628                                 if (ipt->ipt_ptr + sizeof(n_time) +
 629                                     sizeof(struct in_addr) > ipt->ipt_len)
 630                                         goto bad;
 631                                 bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
 632                                     sizeof(struct in_addr));
 633                                 if (ifa_ifwithaddr((SA)&ipaddr) == 0)
 634                                         continue;
 635                                 ipt->ipt_ptr += sizeof(struct in_addr);
 636                                 break;
 637
 638                         default:
 639                                 goto bad;
 640                         }
 641                         ntime = iptime();
 642                         bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
 643                             sizeof(n_time));
 644                         ipt->ipt_ptr += sizeof(n_time);
 645                 }
 646         }
 647         if (forward) {
 648                 ip_forward(m, 1);
 649                 return (1);
 650         }
 651         return (0);
 652 bad:
 653         icmp_error(m, type, code, 0, 0);
 654
 655         return (1);
 656 }
 657
 658 #endif /* notdef */
 659
 660 /*
 661  * Strip out IP options, at higher
 662  * level protocol in the kernel.
 663  * Second argument is buffer to which options
 664  * will be moved, and return value is their length.
 665  * (XXX) should be deleted; last arg currently ignored.
 666  */
 667 void
 668 ip_stripoptions(register struct mbuf *m, struct mbuf *mopt)
 669 {
 670         register int i;
 671         struct ip *ip = mtod(m, struct ip *);
 672         register caddr_t opts;
 673         int olen;
 674
 675         olen = (ip->ip_hl<<2) - sizeof (struct ip);
 676         opts = (caddr_t)(ip + 1);
 677         i = m->m_len - (sizeof (struct ip) + olen);
 678         memcpy(opts, opts  + olen, (unsigned)i);
 679         m->m_len -= olen;
 680
 681         ip->ip_hl = sizeof(struct ip) >> 2;
 682 }