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