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