File:  [Qemu by Fabrice Bellard] / qemu / slirp / ip_input.c
Revision 1.1.1.9 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 19:02:50 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu1000, qemu0151, HEAD
qemu 0.15.1

    1: /*
    2:  * Copyright (c) 1982, 1986, 1988, 1993
    3:  *	The Regents of the University of California.  All rights reserved.
    4:  *
    5:  * Redistribution and use in source and binary forms, with or without
    6:  * modification, are permitted provided that the following conditions
    7:  * are met:
    8:  * 1. Redistributions of source code must retain the above copyright
    9:  *    notice, this list of conditions and the following disclaimer.
   10:  * 2. Redistributions in binary form must reproduce the above copyright
   11:  *    notice, this list of conditions and the following disclaimer in the
   12:  *    documentation and/or other materials provided with the distribution.
   13:  * 3. Neither the name of the University nor the names of its contributors
   14:  *    may be used to endorse or promote products derived from this software
   15:  *    without specific prior written permission.
   16:  *
   17:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27:  * SUCH DAMAGE.
   28:  *
   29:  *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
   30:  * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
   31:  */
   32: 
   33: /*
   34:  * Changes and additions relating to SLiRP are
   35:  * Copyright (c) 1995 Danny Gasparovski.
   36:  *
   37:  * Please read the file COPYRIGHT for the
   38:  * terms and conditions of the copyright.
   39:  */
   40: 
   41: #include <slirp.h>
   42: #include <osdep.h>
   43: #include "ip_icmp.h"
   44: 
   45: static struct ip *ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp);
   46: static void ip_freef(Slirp *slirp, struct ipq *fp);
   47: static void ip_enq(register struct ipasfrag *p,
   48:                    register struct ipasfrag *prev);
   49: static void ip_deq(register struct ipasfrag *p);
   50: 
   51: /*
   52:  * IP initialization: fill in IP protocol switch table.
   53:  * All protocols not implemented in kernel go to raw IP protocol handler.
   54:  */
   55: void
   56: ip_init(Slirp *slirp)
   57: {
   58:     slirp->ipq.ip_link.next = slirp->ipq.ip_link.prev = &slirp->ipq.ip_link;
   59:     udp_init(slirp);
   60:     tcp_init(slirp);
   61:     icmp_init(slirp);
   62: }
   63: 
   64: /*
   65:  * Ip input routine.  Checksum and byte swap header.  If fragmented
   66:  * try to reassemble.  Process options.  Pass to next level.
   67:  */
   68: void
   69: ip_input(struct mbuf *m)
   70: {
   71: 	Slirp *slirp = m->slirp;
   72: 	register struct ip *ip;
   73: 	int hlen;
   74: 
   75: 	DEBUG_CALL("ip_input");
   76: 	DEBUG_ARG("m = %lx", (long)m);
   77: 	DEBUG_ARG("m_len = %d", m->m_len);
   78: 
   79: 	if (m->m_len < sizeof (struct ip)) {
   80: 		return;
   81: 	}
   82: 
   83: 	ip = mtod(m, struct ip *);
   84: 
   85: 	if (ip->ip_v != IPVERSION) {
   86: 		goto bad;
   87: 	}
   88: 
   89: 	hlen = ip->ip_hl << 2;
   90: 	if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
   91: 	  goto bad;                                  /* or packet too short */
   92: 	}
   93: 
   94:         /* keep ip header intact for ICMP reply
   95: 	 * ip->ip_sum = cksum(m, hlen);
   96: 	 * if (ip->ip_sum) {
   97: 	 */
   98: 	if(cksum(m,hlen)) {
   99: 	  goto bad;
  100: 	}
  101: 
  102: 	/*
  103: 	 * Convert fields to host representation.
  104: 	 */
  105: 	NTOHS(ip->ip_len);
  106: 	if (ip->ip_len < hlen) {
  107: 		goto bad;
  108: 	}
  109: 	NTOHS(ip->ip_id);
  110: 	NTOHS(ip->ip_off);
  111: 
  112: 	/*
  113: 	 * Check that the amount of data in the buffers
  114: 	 * is as at least much as the IP header would have us expect.
  115: 	 * Trim mbufs if longer than we expect.
  116: 	 * Drop packet if shorter than we expect.
  117: 	 */
  118: 	if (m->m_len < ip->ip_len) {
  119: 		goto bad;
  120: 	}
  121: 
  122: 	/* Should drop packet if mbuf too long? hmmm... */
  123: 	if (m->m_len > ip->ip_len)
  124: 	   m_adj(m, ip->ip_len - m->m_len);
  125: 
  126: 	/* check ip_ttl for a correct ICMP reply */
  127: 	if(ip->ip_ttl==0) {
  128: 	  icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
  129: 	  goto bad;
  130: 	}
  131: 
  132: 	/*
  133: 	 * If offset or IP_MF are set, must reassemble.
  134: 	 * Otherwise, nothing need be done.
  135: 	 * (We could look in the reassembly queue to see
  136: 	 * if the packet was previously fragmented,
  137: 	 * but it's not worth the time; just let them time out.)
  138: 	 *
  139: 	 * XXX This should fail, don't fragment yet
  140: 	 */
  141: 	if (ip->ip_off &~ IP_DF) {
  142: 	  register struct ipq *fp;
  143:       struct qlink *l;
  144: 		/*
  145: 		 * Look for queue of fragments
  146: 		 * of this datagram.
  147: 		 */
  148: 		for (l = slirp->ipq.ip_link.next; l != &slirp->ipq.ip_link;
  149: 		     l = l->next) {
  150:             fp = container_of(l, struct ipq, ip_link);
  151:             if (ip->ip_id == fp->ipq_id &&
  152:                     ip->ip_src.s_addr == fp->ipq_src.s_addr &&
  153:                     ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
  154:                     ip->ip_p == fp->ipq_p)
  155: 		    goto found;
  156:         }
  157:         fp = NULL;
  158: 	found:
  159: 
  160: 		/*
  161: 		 * Adjust ip_len to not reflect header,
  162: 		 * set ip_mff if more fragments are expected,
  163: 		 * convert offset of this to bytes.
  164: 		 */
  165: 		ip->ip_len -= hlen;
  166: 		if (ip->ip_off & IP_MF)
  167: 		  ip->ip_tos |= 1;
  168: 		else
  169: 		  ip->ip_tos &= ~1;
  170: 
  171: 		ip->ip_off <<= 3;
  172: 
  173: 		/*
  174: 		 * If datagram marked as having more fragments
  175: 		 * or if this is not the first fragment,
  176: 		 * attempt reassembly; if it succeeds, proceed.
  177: 		 */
  178: 		if (ip->ip_tos & 1 || ip->ip_off) {
  179: 			ip = ip_reass(slirp, ip, fp);
  180:                         if (ip == NULL)
  181: 				return;
  182: 			m = dtom(slirp, ip);
  183: 		} else
  184: 			if (fp)
  185: 		   	   ip_freef(slirp, fp);
  186: 
  187: 	} else
  188: 		ip->ip_len -= hlen;
  189: 
  190: 	/*
  191: 	 * Switch out to protocol's input routine.
  192: 	 */
  193: 	switch (ip->ip_p) {
  194: 	 case IPPROTO_TCP:
  195: 		tcp_input(m, hlen, (struct socket *)NULL);
  196: 		break;
  197: 	 case IPPROTO_UDP:
  198: 		udp_input(m, hlen);
  199: 		break;
  200: 	 case IPPROTO_ICMP:
  201: 		icmp_input(m, hlen);
  202: 		break;
  203: 	 default:
  204: 		m_free(m);
  205: 	}
  206: 	return;
  207: bad:
  208: 	m_free(m);
  209: 	return;
  210: }
  211: 
  212: #define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
  213: #define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))
  214: /*
  215:  * Take incoming datagram fragment and try to
  216:  * reassemble it into whole datagram.  If a chain for
  217:  * reassembly of this datagram already exists, then it
  218:  * is given as fp; otherwise have to make a chain.
  219:  */
  220: static struct ip *
  221: ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp)
  222: {
  223: 	register struct mbuf *m = dtom(slirp, ip);
  224: 	register struct ipasfrag *q;
  225: 	int hlen = ip->ip_hl << 2;
  226: 	int i, next;
  227: 
  228: 	DEBUG_CALL("ip_reass");
  229: 	DEBUG_ARG("ip = %lx", (long)ip);
  230: 	DEBUG_ARG("fp = %lx", (long)fp);
  231: 	DEBUG_ARG("m = %lx", (long)m);
  232: 
  233: 	/*
  234: 	 * Presence of header sizes in mbufs
  235: 	 * would confuse code below.
  236:          * Fragment m_data is concatenated.
  237: 	 */
  238: 	m->m_data += hlen;
  239: 	m->m_len -= hlen;
  240: 
  241: 	/*
  242: 	 * If first fragment to arrive, create a reassembly queue.
  243: 	 */
  244:         if (fp == NULL) {
  245: 	  struct mbuf *t = m_get(slirp);
  246: 
  247: 	  if (t == NULL) {
  248: 	      goto dropfrag;
  249: 	  }
  250: 	  fp = mtod(t, struct ipq *);
  251: 	  insque(&fp->ip_link, &slirp->ipq.ip_link);
  252: 	  fp->ipq_ttl = IPFRAGTTL;
  253: 	  fp->ipq_p = ip->ip_p;
  254: 	  fp->ipq_id = ip->ip_id;
  255: 	  fp->frag_link.next = fp->frag_link.prev = &fp->frag_link;
  256: 	  fp->ipq_src = ip->ip_src;
  257: 	  fp->ipq_dst = ip->ip_dst;
  258: 	  q = (struct ipasfrag *)fp;
  259: 	  goto insert;
  260: 	}
  261: 
  262: 	/*
  263: 	 * Find a segment which begins after this one does.
  264: 	 */
  265: 	for (q = fp->frag_link.next; q != (struct ipasfrag *)&fp->frag_link;
  266:             q = q->ipf_next)
  267: 		if (q->ipf_off > ip->ip_off)
  268: 			break;
  269: 
  270: 	/*
  271: 	 * If there is a preceding segment, it may provide some of
  272: 	 * our data already.  If so, drop the data from the incoming
  273: 	 * segment.  If it provides all of our data, drop us.
  274: 	 */
  275: 	if (q->ipf_prev != &fp->frag_link) {
  276:         struct ipasfrag *pq = q->ipf_prev;
  277: 		i = pq->ipf_off + pq->ipf_len - ip->ip_off;
  278: 		if (i > 0) {
  279: 			if (i >= ip->ip_len)
  280: 				goto dropfrag;
  281: 			m_adj(dtom(slirp, ip), i);
  282: 			ip->ip_off += i;
  283: 			ip->ip_len -= i;
  284: 		}
  285: 	}
  286: 
  287: 	/*
  288: 	 * While we overlap succeeding segments trim them or,
  289: 	 * if they are completely covered, dequeue them.
  290: 	 */
  291: 	while (q != (struct ipasfrag*)&fp->frag_link &&
  292:             ip->ip_off + ip->ip_len > q->ipf_off) {
  293: 		i = (ip->ip_off + ip->ip_len) - q->ipf_off;
  294: 		if (i < q->ipf_len) {
  295: 			q->ipf_len -= i;
  296: 			q->ipf_off += i;
  297: 			m_adj(dtom(slirp, q), i);
  298: 			break;
  299: 		}
  300: 		q = q->ipf_next;
  301: 		m_free(dtom(slirp, q->ipf_prev));
  302: 		ip_deq(q->ipf_prev);
  303: 	}
  304: 
  305: insert:
  306: 	/*
  307: 	 * Stick new segment in its place;
  308: 	 * check for complete reassembly.
  309: 	 */
  310: 	ip_enq(iptofrag(ip), q->ipf_prev);
  311: 	next = 0;
  312: 	for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link;
  313:             q = q->ipf_next) {
  314: 		if (q->ipf_off != next)
  315:                         return NULL;
  316: 		next += q->ipf_len;
  317: 	}
  318: 	if (((struct ipasfrag *)(q->ipf_prev))->ipf_tos & 1)
  319:                 return NULL;
  320: 
  321: 	/*
  322: 	 * Reassembly is complete; concatenate fragments.
  323: 	 */
  324:     q = fp->frag_link.next;
  325: 	m = dtom(slirp, q);
  326: 
  327: 	q = (struct ipasfrag *) q->ipf_next;
  328: 	while (q != (struct ipasfrag*)&fp->frag_link) {
  329: 	  struct mbuf *t = dtom(slirp, q);
  330: 	  q = (struct ipasfrag *) q->ipf_next;
  331: 	  m_cat(m, t);
  332: 	}
  333: 
  334: 	/*
  335: 	 * Create header for new ip packet by
  336: 	 * modifying header of first packet;
  337: 	 * dequeue and discard fragment reassembly header.
  338: 	 * Make header visible.
  339: 	 */
  340: 	q = fp->frag_link.next;
  341: 
  342: 	/*
  343: 	 * If the fragments concatenated to an mbuf that's
  344: 	 * bigger than the total size of the fragment, then and
  345: 	 * m_ext buffer was alloced. But fp->ipq_next points to
  346: 	 * the old buffer (in the mbuf), so we must point ip
  347: 	 * into the new buffer.
  348: 	 */
  349: 	if (m->m_flags & M_EXT) {
  350: 	  int delta = (char *)q - m->m_dat;
  351: 	  q = (struct ipasfrag *)(m->m_ext + delta);
  352: 	}
  353: 
  354:     ip = fragtoip(q);
  355: 	ip->ip_len = next;
  356: 	ip->ip_tos &= ~1;
  357: 	ip->ip_src = fp->ipq_src;
  358: 	ip->ip_dst = fp->ipq_dst;
  359: 	remque(&fp->ip_link);
  360: 	(void) m_free(dtom(slirp, fp));
  361: 	m->m_len += (ip->ip_hl << 2);
  362: 	m->m_data -= (ip->ip_hl << 2);
  363: 
  364: 	return ip;
  365: 
  366: dropfrag:
  367: 	m_free(m);
  368:         return NULL;
  369: }
  370: 
  371: /*
  372:  * Free a fragment reassembly header and all
  373:  * associated datagrams.
  374:  */
  375: static void
  376: ip_freef(Slirp *slirp, struct ipq *fp)
  377: {
  378: 	register struct ipasfrag *q, *p;
  379: 
  380: 	for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link; q = p) {
  381: 		p = q->ipf_next;
  382: 		ip_deq(q);
  383: 		m_free(dtom(slirp, q));
  384: 	}
  385: 	remque(&fp->ip_link);
  386: 	(void) m_free(dtom(slirp, fp));
  387: }
  388: 
  389: /*
  390:  * Put an ip fragment on a reassembly chain.
  391:  * Like insque, but pointers in middle of structure.
  392:  */
  393: static void
  394: ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)
  395: {
  396: 	DEBUG_CALL("ip_enq");
  397: 	DEBUG_ARG("prev = %lx", (long)prev);
  398: 	p->ipf_prev =  prev;
  399: 	p->ipf_next = prev->ipf_next;
  400: 	((struct ipasfrag *)(prev->ipf_next))->ipf_prev = p;
  401: 	prev->ipf_next = p;
  402: }
  403: 
  404: /*
  405:  * To ip_enq as remque is to insque.
  406:  */
  407: static void
  408: ip_deq(register struct ipasfrag *p)
  409: {
  410: 	((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
  411: 	((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
  412: }
  413: 
  414: /*
  415:  * IP timer processing;
  416:  * if a timer expires on a reassembly
  417:  * queue, discard it.
  418:  */
  419: void
  420: ip_slowtimo(Slirp *slirp)
  421: {
  422:     struct qlink *l;
  423: 
  424: 	DEBUG_CALL("ip_slowtimo");
  425: 
  426:     l = slirp->ipq.ip_link.next;
  427: 
  428:         if (l == NULL)
  429: 	   return;
  430: 
  431:     while (l != &slirp->ipq.ip_link) {
  432:         struct ipq *fp = container_of(l, struct ipq, ip_link);
  433:         l = l->next;
  434: 		if (--fp->ipq_ttl == 0) {
  435: 			ip_freef(slirp, fp);
  436: 		}
  437:     }
  438: }
  439: 
  440: /*
  441:  * Do option processing on a datagram,
  442:  * possibly discarding it if bad options are encountered,
  443:  * or forwarding it if source-routed.
  444:  * Returns 1 if packet has been forwarded/freed,
  445:  * 0 if the packet should be processed further.
  446:  */
  447: 
  448: #ifdef notdef
  449: 
  450: int
  451: ip_dooptions(m)
  452: 	struct mbuf *m;
  453: {
  454: 	register struct ip *ip = mtod(m, struct ip *);
  455: 	register u_char *cp;
  456: 	register struct ip_timestamp *ipt;
  457: 	register struct in_ifaddr *ia;
  458: 	int opt, optlen, cnt, off, code, type, forward = 0;
  459: 	struct in_addr *sin, dst;
  460: typedef uint32_t n_time;
  461: 	n_time ntime;
  462: 
  463: 	dst = ip->ip_dst;
  464: 	cp = (u_char *)(ip + 1);
  465: 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
  466: 	for (; cnt > 0; cnt -= optlen, cp += optlen) {
  467: 		opt = cp[IPOPT_OPTVAL];
  468: 		if (opt == IPOPT_EOL)
  469: 			break;
  470: 		if (opt == IPOPT_NOP)
  471: 			optlen = 1;
  472: 		else {
  473: 			optlen = cp[IPOPT_OLEN];
  474: 			if (optlen <= 0 || optlen > cnt) {
  475: 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
  476: 				goto bad;
  477: 			}
  478: 		}
  479: 		switch (opt) {
  480: 
  481: 		default:
  482: 			break;
  483: 
  484: 		/*
  485: 		 * Source routing with record.
  486: 		 * Find interface with current destination address.
  487: 		 * If none on this machine then drop if strictly routed,
  488: 		 * or do nothing if loosely routed.
  489: 		 * Record interface address and bring up next address
  490: 		 * component.  If strictly routed make sure next
  491: 		 * address is on directly accessible net.
  492: 		 */
  493: 		case IPOPT_LSRR:
  494: 		case IPOPT_SSRR:
  495: 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
  496: 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
  497: 				goto bad;
  498: 			}
  499: 			ipaddr.sin_addr = ip->ip_dst;
  500: 			ia = (struct in_ifaddr *)
  501: 				ifa_ifwithaddr((struct sockaddr *)&ipaddr);
  502: 			if (ia == 0) {
  503: 				if (opt == IPOPT_SSRR) {
  504: 					type = ICMP_UNREACH;
  505: 					code = ICMP_UNREACH_SRCFAIL;
  506: 					goto bad;
  507: 				}
  508: 				/*
  509: 				 * Loose routing, and not at next destination
  510: 				 * yet; nothing to do except forward.
  511: 				 */
  512: 				break;
  513: 			}
  514: 			off--;			/ * 0 origin *  /
  515: 			if (off > optlen - sizeof(struct in_addr)) {
  516: 				/*
  517: 				 * End of source route.  Should be for us.
  518: 				 */
  519: 				save_rte(cp, ip->ip_src);
  520: 				break;
  521: 			}
  522: 			/*
  523: 			 * locate outgoing interface
  524: 			 */
  525: 			bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
  526: 			    sizeof(ipaddr.sin_addr));
  527: 			if (opt == IPOPT_SSRR) {
  528: #define	INA	struct in_ifaddr *
  529: #define	SA	struct sockaddr *
  530:  			    if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
  531: 				ia = (INA)ifa_ifwithnet((SA)&ipaddr);
  532: 			} else
  533: 				ia = ip_rtaddr(ipaddr.sin_addr);
  534: 			if (ia == 0) {
  535: 				type = ICMP_UNREACH;
  536: 				code = ICMP_UNREACH_SRCFAIL;
  537: 				goto bad;
  538: 			}
  539: 			ip->ip_dst = ipaddr.sin_addr;
  540: 			bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
  541: 			    (caddr_t)(cp + off), sizeof(struct in_addr));
  542: 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
  543: 			/*
  544: 			 * Let ip_intr's mcast routing check handle mcast pkts
  545: 			 */
  546: 			forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
  547: 			break;
  548: 
  549: 		case IPOPT_RR:
  550: 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
  551: 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
  552: 				goto bad;
  553: 			}
  554: 			/*
  555: 			 * If no space remains, ignore.
  556: 			 */
  557: 			off--;			 * 0 origin *
  558: 			if (off > optlen - sizeof(struct in_addr))
  559: 				break;
  560: 			bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
  561: 			    sizeof(ipaddr.sin_addr));
  562: 			/*
  563: 			 * locate outgoing interface; if we're the destination,
  564: 			 * use the incoming interface (should be same).
  565: 			 */
  566: 			if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
  567: 			    (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
  568: 				type = ICMP_UNREACH;
  569: 				code = ICMP_UNREACH_HOST;
  570: 				goto bad;
  571: 			}
  572: 			bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
  573: 			    (caddr_t)(cp + off), sizeof(struct in_addr));
  574: 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
  575: 			break;
  576: 
  577: 		case IPOPT_TS:
  578: 			code = cp - (u_char *)ip;
  579: 			ipt = (struct ip_timestamp *)cp;
  580: 			if (ipt->ipt_len < 5)
  581: 				goto bad;
  582: 			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
  583: 				if (++ipt->ipt_oflw == 0)
  584: 					goto bad;
  585: 				break;
  586: 			}
  587: 			sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
  588: 			switch (ipt->ipt_flg) {
  589: 
  590: 			case IPOPT_TS_TSONLY:
  591: 				break;
  592: 
  593: 			case IPOPT_TS_TSANDADDR:
  594: 				if (ipt->ipt_ptr + sizeof(n_time) +
  595: 				    sizeof(struct in_addr) > ipt->ipt_len)
  596: 					goto bad;
  597: 				ipaddr.sin_addr = dst;
  598: 				ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,
  599: 							    m->m_pkthdr.rcvif);
  600: 				if (ia == 0)
  601: 					continue;
  602: 				bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
  603: 				    (caddr_t)sin, sizeof(struct in_addr));
  604: 				ipt->ipt_ptr += sizeof(struct in_addr);
  605: 				break;
  606: 
  607: 			case IPOPT_TS_PRESPEC:
  608: 				if (ipt->ipt_ptr + sizeof(n_time) +
  609: 				    sizeof(struct in_addr) > ipt->ipt_len)
  610: 					goto bad;
  611: 				bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
  612: 				    sizeof(struct in_addr));
  613: 				if (ifa_ifwithaddr((SA)&ipaddr) == 0)
  614: 					continue;
  615: 				ipt->ipt_ptr += sizeof(struct in_addr);
  616: 				break;
  617: 
  618: 			default:
  619: 				goto bad;
  620: 			}
  621: 			ntime = iptime();
  622: 			bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
  623: 			    sizeof(n_time));
  624: 			ipt->ipt_ptr += sizeof(n_time);
  625: 		}
  626: 	}
  627: 	if (forward) {
  628: 		ip_forward(m, 1);
  629: 		return (1);
  630: 	}
  631: 	return (0);
  632: bad:
  633:  	icmp_error(m, type, code, 0, 0);
  634: 
  635: 	return (1);
  636: }
  637: 
  638: #endif /* notdef */
  639: 
  640: /*
  641:  * Strip out IP options, at higher
  642:  * level protocol in the kernel.
  643:  * Second argument is buffer to which options
  644:  * will be moved, and return value is their length.
  645:  * (XXX) should be deleted; last arg currently ignored.
  646:  */
  647: void
  648: ip_stripoptions(register struct mbuf *m, struct mbuf *mopt)
  649: {
  650: 	register int i;
  651: 	struct ip *ip = mtod(m, struct ip *);
  652: 	register caddr_t opts;
  653: 	int olen;
  654: 
  655: 	olen = (ip->ip_hl<<2) - sizeof (struct ip);
  656: 	opts = (caddr_t)(ip + 1);
  657: 	i = m->m_len - (sizeof (struct ip) + olen);
  658: 	memcpy(opts, opts  + olen, (unsigned)i);
  659: 	m->m_len -= olen;
  660: 
  661: 	ip->ip_hl = sizeof(struct ip) >> 2;
  662: }

unix.superglobalmegacorp.com