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      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 <qemu/osdep.h>
     43 #include "ip_icmp.h"
     44 
     45 #ifdef LOG_ENABLED
     46 struct ipstat ipstat;
     47 #endif
     48 
     49 struct ipq ipq;
     50 
     51 static struct ip *ip_reass(register struct ip *ip,
     52                            register struct ipq *fp);
     53 static void ip_freef(struct ipq *fp);
     54 static void ip_enq(register struct ipasfrag *p,
     55                    register struct ipasfrag *prev);
     56 static void ip_deq(register struct ipasfrag *p);
     57 
     58 /*
     59  * IP initialization: fill in IP protocol switch table.
     60  * All protocols not implemented in kernel go to raw IP protocol handler.
     61  */
     62 void
     63 ip_init(void)
     64 {
     65 	ipq.ip_link.next = ipq.ip_link.prev = &ipq.ip_link;
     66 	ip_id = tt.tv_sec & 0xffff;
     67 	udp_init();
     68 	tcp_init();
     69 }
     70 
     71 /*
     72  * Ip input routine.  Checksum and byte swap header.  If fragmented
     73  * try to reassemble.  Process options.  Pass to next level.
     74  */
     75 void
     76 ip_input(struct mbuf *m)
     77 {
     78 	register struct ip *ip;
     79 	int hlen;
     80 
     81 	DEBUG_CALL("ip_input");
     82 	DEBUG_ARG("m = %lx", (long)m);
     83 	DEBUG_ARG("m_len = %d", m->m_len);
     84 
     85 	STAT(ipstat.ips_total++);
     86 
     87 	if (m->m_len < sizeof (struct ip)) {
     88 		STAT(ipstat.ips_toosmall++);
     89 		return;
     90 	}
     91 
     92 	ip = mtod(m, struct ip *);
     93 
     94 	if (ip->ip_v != IPVERSION) {
     95 		STAT(ipstat.ips_badvers++);
     96 		goto bad;
     97 	}
     98 
     99 	hlen = ip->ip_hl << 2;
    100 	if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
    101 	  STAT(ipstat.ips_badhlen++);                     /* or packet too short */
    102 	  goto bad;
    103 	}
    104 
    105         /* keep ip header intact for ICMP reply
    106 	 * ip->ip_sum = cksum(m, hlen);
    107 	 * if (ip->ip_sum) {
    108 	 */
    109 	if(cksum(m,hlen)) {
    110 	  STAT(ipstat.ips_badsum++);
    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 		STAT(ipstat.ips_badlen++);
    120 		goto bad;
    121 	}
    122 	NTOHS(ip->ip_id);
    123 	NTOHS(ip->ip_off);
    124 
    125 	/*
    126 	 * Check that the amount of data in the buffers
    127 	 * is as at least much as the IP header would have us expect.
    128 	 * Trim mbufs if longer than we expect.
    129 	 * Drop packet if shorter than we expect.
    130 	 */
    131 	if (m->m_len < ip->ip_len) {
    132 		STAT(ipstat.ips_tooshort++);
    133 		goto bad;
    134 	}
    135 
    136     if (slirp_restrict) {
    137         if (ip_geth(ip->ip_dst) != special_addr_ip) {
    138             if (ip_getn(ip->ip_dst) == 0xffffffffu && ip->ip_p != IPPROTO_UDP)
    139                 goto bad;
    140         } else {
    141             int host = ip_geth(ip->ip_dst) & 0xff;
    142             struct ex_list *ex_ptr;
    143 
    144             if (host == 0xff)
    145                 goto bad;
    146 
    147             for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next)
    148                 if (ex_ptr->ex_addr == host)
    149                     break;
    150 
    151             if (!ex_ptr)
    152                 goto bad;
    153         }
    154     }
    155 
    156 	/* Should drop packet if mbuf too long? hmmm... */
    157 	if (m->m_len > ip->ip_len)
    158 	   m_adj(m, ip->ip_len - m->m_len);
    159 
    160 	/* check ip_ttl for a correct ICMP reply */
    161 	if(ip->ip_ttl==0 || ip->ip_ttl==1) {
    162 	  icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
    163 	  goto bad;
    164 	}
    165 
    166 	/*
    167 	 * Process options and, if not destined for us,
    168 	 * ship it on.  ip_dooptions returns 1 when an
    169 	 * error was detected (causing an icmp message
    170 	 * to be sent and the original packet to be freed).
    171 	 */
    172 /* We do no IP options */
    173 /*	if (hlen > sizeof (struct ip) && ip_dooptions(m))
    174  *		goto next;
    175  */
    176 	/*
    177 	 * If offset or IP_MF are set, must reassemble.
    178 	 * Otherwise, nothing need be done.
    179 	 * (We could look in the reassembly queue to see
    180 	 * if the packet was previously fragmented,
    181 	 * but it's not worth the time; just let them time out.)
    182 	 *
    183 	 * XXX This should fail, don't fragment yet
    184 	 */
    185 	if (ip->ip_off &~ IP_DF) {
    186 	  register struct ipq *fp;
    187       struct qlink *l;
    188 		/*
    189 		 * Look for queue of fragments
    190 		 * of this datagram.
    191 		 */
    192 		for (l = ipq.ip_link.next; l != &ipq.ip_link; l = l->next) {
    193             fp = container_of(l, struct ipq, ip_link);
    194             if (ip->ip_id == fp->ipq_id &&
    195 		      ip_equal(ip->ip_src, fp->ipq_src) &&
    196 		      ip_equal(ip->ip_dst, fp->ipq_dst) &&
    197 		      ip->ip_p == fp->ipq_p)
    198 		    goto found;
    199         }
    200         fp = NULL;
    201 	found:
    202 
    203 		/*
    204 		 * Adjust ip_len to not reflect header,
    205 		 * set ip_mff if more fragments are expected,
    206 		 * convert offset of this to bytes.
    207 		 */
    208 		ip->ip_len -= hlen;
    209 		if (ip->ip_off & IP_MF)
    210 		  ip->ip_tos |= 1;
    211 		else
    212 		  ip->ip_tos &= ~1;
    213 
    214 		ip->ip_off <<= 3;
    215 
    216 		/*
    217 		 * If datagram marked as having more fragments
    218 		 * or if this is not the first fragment,
    219 		 * attempt reassembly; if it succeeds, proceed.
    220 		 */
    221 		if (ip->ip_tos & 1 || ip->ip_off) {
    222 			STAT(ipstat.ips_fragments++);
    223 			ip = ip_reass(ip, fp);
    224 			if (ip == NULL)
    225 				return;
    226 			STAT(ipstat.ips_reassembled++);
    227 			m = dtom(ip);
    228 		} else
    229 			if (fp)
    230 		   	   ip_freef(fp);
    231 
    232 	} else
    233 		ip->ip_len -= hlen;
    234 
    235 	/*
    236 	 * Switch out to protocol's input routine.
    237 	 */
    238 	STAT(ipstat.ips_delivered++);
    239 	switch (ip->ip_p) {
    240 	 case IPPROTO_TCP:
    241 		tcp_input(m, hlen, (struct socket *)NULL);
    242 		break;
    243 	 case IPPROTO_UDP:
    244 		udp_input(m, hlen);
    245 		break;
    246 	 case IPPROTO_ICMP:
    247 		icmp_input(m, hlen);
    248 		break;
    249 	 default:
    250 		STAT(ipstat.ips_noproto++);
    251 		m_free(m);
    252 	}
    253 	return;
    254 bad:
    255 	m_freem(m);
    256 	return;
    257 }
    258 
    259 #define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
    260 #define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))
    261 /*
    262  * Take incoming datagram fragment and try to
    263  * reassemble it into whole datagram.  If a chain for
    264  * reassembly of this datagram already exists, then it
    265  * is given as fp; otherwise have to make a chain.
    266  */
    267 static struct ip *
    268 ip_reass(register struct ip *ip, register struct ipq *fp)
    269 {
    270 	register struct mbuf *m = dtom(ip);
    271 	register struct ipasfrag *q;
    272 	int hlen = ip->ip_hl << 2;
    273 	int i, next;
    274 
    275 	DEBUG_CALL("ip_reass");
    276 	DEBUG_ARG("ip = %lx", (long)ip);
    277 	DEBUG_ARG("fp = %lx", (long)fp);
    278 	DEBUG_ARG("m = %lx", (long)m);
    279 
    280 	/*
    281 	 * Presence of header sizes in mbufs
    282 	 * would confuse code below.
    283          * Fragment m_data is concatenated.
    284 	 */
    285 	m->m_data += hlen;
    286 	m->m_len -= hlen;
    287 
    288 	/*
    289 	 * If first fragment to arrive, create a reassembly queue.
    290 	 */
    291     if (fp == NULL) {
    292 	  struct mbuf *t;
    293 	  if ((t = m_get()) == NULL) goto dropfrag;
    294 	  fp = mtod(t, struct ipq *);
    295 	  insque(&fp->ip_link, &ipq.ip_link);
    296 	  fp->ipq_ttl = IPFRAGTTL;
    297 	  fp->ipq_p = ip->ip_p;
    298 	  fp->ipq_id = ip->ip_id;
    299 	  fp->frag_link.next = fp->frag_link.prev = &fp->frag_link;
    300 	  fp->ipq_src = ip->ip_src;
    301 	  fp->ipq_dst = ip->ip_dst;
    302 	  q = (struct ipasfrag *)fp;
    303 	  goto insert;
    304 	}
    305 
    306 	/*
    307 	 * Find a segment which begins after this one does.
    308 	 */
    309 	for (q = fp->frag_link.next; q != (struct ipasfrag *)&fp->frag_link;
    310             q = q->ipf_next)
    311 		if (q->ipf_off > ip->ip_off)
    312 			break;
    313 
    314 	/*
    315 	 * If there is a preceding segment, it may provide some of
    316 	 * our data already.  If so, drop the data from the incoming
    317 	 * segment.  If it provides all of our data, drop us.
    318 	 */
    319 	if (q->ipf_prev != &fp->frag_link) {
    320         struct ipasfrag *pq = q->ipf_prev;
    321 		i = pq->ipf_off + pq->ipf_len - ip->ip_off;
    322 		if (i > 0) {
    323 			if (i >= ip->ip_len)
    324 				goto dropfrag;
    325 			m_adj(dtom(ip), i);
    326 			ip->ip_off += i;
    327 			ip->ip_len -= i;
    328 		}
    329 	}
    330 
    331 	/*
    332 	 * While we overlap succeeding segments trim them or,
    333 	 * if they are completely covered, dequeue them.
    334 	 */
    335 	while (q != (struct ipasfrag*)&fp->frag_link &&
    336             ip->ip_off + ip->ip_len > q->ipf_off) {
    337 		i = (ip->ip_off + ip->ip_len) - q->ipf_off;
    338 		if (i < q->ipf_len) {
    339 			q->ipf_len -= i;
    340 			q->ipf_off += i;
    341 			m_adj(dtom(q), i);
    342 			break;
    343 		}
    344 		q = q->ipf_next;
    345 		m_freem(dtom(q->ipf_prev));
    346 		ip_deq(q->ipf_prev);
    347 	}
    348 
    349 insert:
    350 	/*
    351 	 * Stick new segment in its place;
    352 	 * check for complete reassembly.
    353 	 */
    354 	ip_enq(iptofrag(ip), q->ipf_prev);
    355 	next = 0;
    356 	for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link;
    357             q = q->ipf_next) {
    358 		if (q->ipf_off != next)
    359                         return NULL;
    360 		next += q->ipf_len;
    361 	}
    362 	if (((struct ipasfrag *)(q->ipf_prev))->ipf_tos & 1)
    363                 return NULL;
    364 
    365 	/*
    366 	 * Reassembly is complete; concatenate fragments.
    367 	 */
    368     q = fp->frag_link.next;
    369 	m = dtom(q);
    370 
    371 	q = (struct ipasfrag *) q->ipf_next;
    372 	while (q != (struct ipasfrag*)&fp->frag_link) {
    373 	  struct mbuf *t = dtom(q);
    374 	  q = (struct ipasfrag *) q->ipf_next;
    375 	  m_cat(m, t);
    376 	}
    377 
    378 	/*
    379 	 * Create header for new ip packet by
    380 	 * modifying header of first packet;
    381 	 * dequeue and discard fragment reassembly header.
    382 	 * Make header visible.
    383 	 */
    384 	q = fp->frag_link.next;
    385 
    386 	/*
    387 	 * If the fragments concatenated to an mbuf that's
    388 	 * bigger than the total size of the fragment, then and
    389 	 * m_ext buffer was alloced. But fp->ipq_next points to
    390 	 * the old buffer (in the mbuf), so we must point ip
    391 	 * into the new buffer.
    392 	 */
    393 	if (m->m_flags & M_EXT) {
    394 	  int delta = (char *)q - m->m_dat;
    395 	  q = (struct ipasfrag *)(m->m_ext + delta);
    396 	}
    397 
    398 	/* DEBUG_ARG("ip = %lx", (long)ip);
    399 	 * ip=(struct ipasfrag *)m->m_data; */
    400 
    401     ip = fragtoip(q);
    402 	ip->ip_len = next;
    403 	ip->ip_tos &= ~1;
    404 	ip->ip_src = fp->ipq_src;
    405 	ip->ip_dst = fp->ipq_dst;
    406 	remque(&fp->ip_link);
    407 	(void) m_free(dtom(fp));
    408 	m->m_len += (ip->ip_hl << 2);
    409 	m->m_data -= (ip->ip_hl << 2);
    410 
    411 	return ip;
    412 
    413 dropfrag:
    414 	STAT(ipstat.ips_fragdropped++);
    415 	m_freem(m);
    416     return NULL;
    417 }
    418 
    419 /*
    420  * Free a fragment reassembly header and all
    421  * associated datagrams.
    422  */
    423 static void
    424 ip_freef(struct ipq *fp)
    425 {
    426 	register struct ipasfrag *q, *p;
    427 
    428 	for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link; q = p) {
    429 		p = q->ipf_next;
    430 		ip_deq(q);
    431 		m_freem(dtom(q));
    432 	}
    433 	remque(&fp->ip_link);
    434 	(void) m_free(dtom(fp));
    435 }
    436 
    437 /*
    438  * Put an ip fragment on a reassembly chain.
    439  * Like insque, but pointers in middle of structure.
    440  */
    441 static void
    442 ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)
    443 {
    444 	DEBUG_CALL("ip_enq");
    445 	DEBUG_ARG("prev = %lx", (long)prev);
    446 	p->ipf_prev =  prev;
    447 	p->ipf_next = prev->ipf_next;
    448 	((struct ipasfrag *)(prev->ipf_next))->ipf_prev = p;
    449 	prev->ipf_next = p;
    450 }
    451 
    452 /*
    453  * To ip_enq as remque is to insque.
    454  */
    455 static void
    456 ip_deq(register struct ipasfrag *p)
    457 {
    458 	((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
    459 	((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
    460 }
    461 
    462 /*
    463  * IP timer processing;
    464  * if a timer expires on a reassembly
    465  * queue, discard it.
    466  */
    467 void
    468 ip_slowtimo(void)
    469 {
    470     struct qlink *l;
    471 
    472 	DEBUG_CALL("ip_slowtimo");
    473 
    474     l = ipq.ip_link.next;
    475 
    476     if (l == NULL)
    477 	   return;
    478 
    479 	while (l != &ipq.ip_link) {
    480         struct ipq *fp = container_of(l, struct ipq, ip_link);
    481         l = l->next;
    482 		if (--fp->ipq_ttl == 0) {
    483 			STAT(ipstat.ips_fragtimeout++);
    484 			ip_freef(fp);
    485 		}
    486 	}
    487 }
    488 
    489 /*
    490  * Do option processing on a datagram,
    491  * possibly discarding it if bad options are encountered,
    492  * or forwarding it if source-routed.
    493  * Returns 1 if packet has been forwarded/freed,
    494  * 0 if the packet should be processed further.
    495  */
    496 
    497 #ifdef notdef
    498 
    499 int
    500 ip_dooptions(m)
    501 	struct mbuf *m;
    502 {
    503 	register struct ip *ip = mtod(m, struct ip *);
    504 	register u_char *cp;
    505 	register struct ip_timestamp *ipt;
    506 	register struct in_ifaddr *ia;
    507 /*	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; */
    508 	int opt, optlen, cnt, off, code, type, forward = 0;
    509 	ipaddr_t *sin, dst;
    510 typedef u_int32_t n_time;
    511 	n_time ntime;
    512 
    513 	dst = ip->ip_dst;
    514 	cp = (u_char *)(ip + 1);
    515 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
    516 	for (; cnt > 0; cnt -= optlen, cp += optlen) {
    517 		opt = cp[IPOPT_OPTVAL];
    518 		if (opt == IPOPT_EOL)
    519 			break;
    520 		if (opt == IPOPT_NOP)
    521 			optlen = 1;
    522 		else {
    523 			optlen = cp[IPOPT_OLEN];
    524 			if (optlen <= 0 || optlen > cnt) {
    525 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    526 				goto bad;
    527 			}
    528 		}
    529 		switch (opt) {
    530 
    531 		default:
    532 			break;
    533 
    534 		/*
    535 		 * Source routing with record.
    536 		 * Find interface with current destination address.
    537 		 * If none on this machine then drop if strictly routed,
    538 		 * or do nothing if loosely routed.
    539 		 * Record interface address and bring up next address
    540 		 * component.  If strictly routed make sure next
    541 		 * address is on directly accessible net.
    542 		 */
    543 		case IPOPT_LSRR:
    544 		case IPOPT_SSRR:
    545 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
    546 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
    547 				goto bad;
    548 			}
    549 			ipaddr.sin_addr = ip->ip_dst;
    550 			ia = (struct in_ifaddr *)
    551 				ifa_ifwithaddr((struct sockaddr *)&ipaddr);
    552 			if (ia == 0) {
    553 				if (opt == IPOPT_SSRR) {
    554 					type = ICMP_UNREACH;
    555 					code = ICMP_UNREACH_SRCFAIL;
    556 					goto bad;
    557 				}
    558 				/*
    559 				 * Loose routing, and not at next destination
    560 				 * yet; nothing to do except forward.
    561 				 */
    562 				break;
    563 			}
    564 			off--;			/ * 0 origin *  /
    565 			if (off > optlen - sizeof(struct in_addr)) {
    566 				/*
    567 				 * End of source route.  Should be for us.
    568 				 */
    569 				save_rte(cp, ip->ip_src);
    570 				break;
    571 			}
    572 			/*
    573 			 * locate outgoing interface
    574 			 */
    575 			bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
    576 			    sizeof(ipaddr.sin_addr));
    577 			if (opt == IPOPT_SSRR) {
    578 #define	INA	struct in_ifaddr *
    579 #define	SA	struct sockaddr *
    580  			    if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
    581 				ia = (INA)ifa_ifwithnet((SA)&ipaddr);
    582 			} else
    583 				ia = ip_rtaddr(ipaddr.sin_addr);
    584 			if (ia == 0) {
    585 				type = ICMP_UNREACH;
    586 				code = ICMP_UNREACH_SRCFAIL;
    587 				goto bad;
    588 			}
    589 			ip->ip_dst = ipaddr.sin_addr;
    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 			/*
    594 			 * Let ip_intr's mcast routing check handle mcast pkts
    595 			 */
    596 			forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
    597 			break;
    598 
    599 		case IPOPT_RR:
    600 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
    601 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
    602 				goto bad;
    603 			}
    604 			/*
    605 			 * If no space remains, ignore.
    606 			 */
    607 			off--;			 * 0 origin *
    608 			if (off > optlen - sizeof(struct in_addr))
    609 				break;
    610 			bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
    611 			    sizeof(ipaddr.sin_addr));
    612 			/*
    613 			 * locate outgoing interface; if we're the destination,
    614 			 * use the incoming interface (should be same).
    615 			 */
    616 			if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
    617 			    (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
    618 				type = ICMP_UNREACH;
    619 				code = ICMP_UNREACH_HOST;
    620 				goto bad;
    621 			}
    622 			bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
    623 			    (caddr_t)(cp + off), sizeof(struct in_addr));
    624 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
    625 			break;
    626 
    627 		case IPOPT_TS:
    628 			code = cp - (u_char *)ip;
    629 			ipt = (struct ip_timestamp *)cp;
    630 			if (ipt->ipt_len < 5)
    631 				goto bad;
    632 			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
    633 				if (++ipt->ipt_oflw == 0)
    634 					goto bad;
    635 				break;
    636 			}
    637 			sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
    638 			switch (ipt->ipt_flg) {
    639 
    640 			case IPOPT_TS_TSONLY:
    641 				break;
    642 
    643 			case IPOPT_TS_TSANDADDR:
    644 				if (ipt->ipt_ptr + sizeof(n_time) +
    645 				    sizeof(struct in_addr) > ipt->ipt_len)
    646 					goto bad;
    647 				ipaddr.sin_addr = dst;
    648 				ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,
    649 							    m->m_pkthdr.rcvif);
    650 				if (ia == 0)
    651 					continue;
    652 				bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
    653 				    (caddr_t)sin, sizeof(struct in_addr));
    654 				ipt->ipt_ptr += sizeof(struct in_addr);
    655 				break;
    656 
    657 			case IPOPT_TS_PRESPEC:
    658 				if (ipt->ipt_ptr + sizeof(n_time) +
    659 				    sizeof(struct in_addr) > ipt->ipt_len)
    660 					goto bad;
    661 				bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
    662 				    sizeof(struct in_addr));
    663 				if (ifa_ifwithaddr((SA)&ipaddr) == 0)
    664 					continue;
    665 				ipt->ipt_ptr += sizeof(struct in_addr);
    666 				break;
    667 
    668 			default:
    669 				goto bad;
    670 			}
    671 			ntime = iptime();
    672 			bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
    673 			    sizeof(n_time));
    674 			ipt->ipt_ptr += sizeof(n_time);
    675 		}
    676 	}
    677 	if (forward) {
    678 		ip_forward(m, 1);
    679 		return (1);
    680 	}
    681 		}
    682 	}
    683 	return (0);
    684 bad:
    685 	/* ip->ip_len -= ip->ip_hl << 2;   XXX icmp_error adds in hdr length */
    686 
    687 /* Not yet */
    688  	icmp_error(m, type, code, 0, 0);
    689 
    690 	STAT(ipstat.ips_badoptions++);
    691 	return (1);
    692 }
    693 
    694 #endif /* notdef */
    695 
    696 /*
    697  * Strip out IP options, at higher
    698  * level protocol in the kernel.
    699  * Second argument is buffer to which options
    700  * will be moved, and return value is their length.
    701  * (XXX) should be deleted; last arg currently ignored.
    702  */
    703 void
    704 ip_stripoptions(register struct mbuf *m, struct mbuf *mopt)
    705 {
    706 	register int i;
    707 	struct ip *ip = mtod(m, struct ip *);
    708 	register caddr_t opts;
    709 	int olen;
    710 
    711 	olen = (ip->ip_hl<<2) - sizeof (struct ip);
    712 	opts = (caddr_t)(ip + 1);
    713 	i = m->m_len - (sizeof (struct ip) + olen);
    714 	memcpy(opts, opts  + olen, (unsigned)i);
    715 	m->m_len -= olen;
    716 
    717 	ip->ip_hl = sizeof(struct ip) >> 2;
    718 }
    719