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