--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/symbian-qemu-0.9.1-12/qemu-symbian-svp/slirp/ip_input.c Fri Jul 31 15:01:17 2009 +0100
@@ -0,0 +1,700 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
+ * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
+ */
+
+/*
+ * Changes and additions relating to SLiRP are
+ * Copyright (c) 1995 Danny Gasparovski.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#include <slirp.h>
+#include "ip_icmp.h"
+
+#ifdef LOG_ENABLED
+struct ipstat ipstat;
+#endif
+
+struct ipq ipq;
+
+static struct ip *ip_reass(register struct ipasfrag *ip,
+ register struct ipq *fp);
+static void ip_freef(struct ipq *fp);
+static void ip_enq(register struct ipasfrag *p,
+ register struct ipasfrag *prev);
+static void ip_deq(register struct ipasfrag *p);
+
+/*
+ * IP initialization: fill in IP protocol switch table.
+ * All protocols not implemented in kernel go to raw IP protocol handler.
+ */
+void
+ip_init()
+{
+ ipq.next = ipq.prev = (ipqp_32)&ipq;
+ ip_id = tt.tv_sec & 0xffff;
+ udp_init();
+ tcp_init();
+}
+
+/*
+ * Ip input routine. Checksum and byte swap header. If fragmented
+ * try to reassemble. Process options. Pass to next level.
+ */
+void
+ip_input(m)
+ struct mbuf *m;
+{
+ register struct ip *ip;
+ int hlen;
+
+ DEBUG_CALL("ip_input");
+ DEBUG_ARG("m = %lx", (long)m);
+ DEBUG_ARG("m_len = %d", m->m_len);
+
+ STAT(ipstat.ips_total++);
+
+ if (m->m_len < sizeof (struct ip)) {
+ STAT(ipstat.ips_toosmall++);
+ return;
+ }
+
+ ip = mtod(m, struct ip *);
+
+ if (ip->ip_v != IPVERSION) {
+ STAT(ipstat.ips_badvers++);
+ goto bad;
+ }
+
+ hlen = ip->ip_hl << 2;
+ if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
+ STAT(ipstat.ips_badhlen++); /* or packet too short */
+ goto bad;
+ }
+
+ /* keep ip header intact for ICMP reply
+ * ip->ip_sum = cksum(m, hlen);
+ * if (ip->ip_sum) {
+ */
+ if(cksum(m,hlen)) {
+ STAT(ipstat.ips_badsum++);
+ goto bad;
+ }
+
+ /*
+ * Convert fields to host representation.
+ */
+ NTOHS(ip->ip_len);
+ if (ip->ip_len < hlen) {
+ STAT(ipstat.ips_badlen++);
+ goto bad;
+ }
+ NTOHS(ip->ip_id);
+ NTOHS(ip->ip_off);
+
+ /*
+ * Check that the amount of data in the buffers
+ * is as at least much as the IP header would have us expect.
+ * Trim mbufs if longer than we expect.
+ * Drop packet if shorter than we expect.
+ */
+ if (m->m_len < ip->ip_len) {
+ STAT(ipstat.ips_tooshort++);
+ goto bad;
+ }
+ /* Should drop packet if mbuf too long? hmmm... */
+ if (m->m_len > ip->ip_len)
+ m_adj(m, ip->ip_len - m->m_len);
+
+ /* check ip_ttl for a correct ICMP reply */
+ if(ip->ip_ttl==0 || ip->ip_ttl==1) {
+ icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
+ goto bad;
+ }
+
+ /*
+ * Process options and, if not destined for us,
+ * ship it on. ip_dooptions returns 1 when an
+ * error was detected (causing an icmp message
+ * to be sent and the original packet to be freed).
+ */
+/* We do no IP options */
+/* if (hlen > sizeof (struct ip) && ip_dooptions(m))
+ * goto next;
+ */
+ /*
+ * If offset or IP_MF are set, must reassemble.
+ * Otherwise, nothing need be done.
+ * (We could look in the reassembly queue to see
+ * if the packet was previously fragmented,
+ * but it's not worth the time; just let them time out.)
+ *
+ * XXX This should fail, don't fragment yet
+ */
+ if (ip->ip_off &~ IP_DF) {
+ register struct ipq *fp;
+ /*
+ * Look for queue of fragments
+ * of this datagram.
+ */
+ for (fp = (struct ipq *) ipq.next; fp != &ipq;
+ fp = (struct ipq *) fp->next)
+ if (ip->ip_id == fp->ipq_id &&
+ ip->ip_src.s_addr == fp->ipq_src.s_addr &&
+ ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
+ ip->ip_p == fp->ipq_p)
+ goto found;
+ fp = 0;
+ found:
+
+ /*
+ * Adjust ip_len to not reflect header,
+ * set ip_mff if more fragments are expected,
+ * convert offset of this to bytes.
+ */
+ ip->ip_len -= hlen;
+ if (ip->ip_off & IP_MF)
+ ((struct ipasfrag *)ip)->ipf_mff |= 1;
+ else
+ ((struct ipasfrag *)ip)->ipf_mff &= ~1;
+
+ ip->ip_off <<= 3;
+
+ /*
+ * If datagram marked as having more fragments
+ * or if this is not the first fragment,
+ * attempt reassembly; if it succeeds, proceed.
+ */
+ if (((struct ipasfrag *)ip)->ipf_mff & 1 || ip->ip_off) {
+ STAT(ipstat.ips_fragments++);
+ ip = ip_reass((struct ipasfrag *)ip, fp);
+ if (ip == 0)
+ return;
+ STAT(ipstat.ips_reassembled++);
+ m = dtom(ip);
+ } else
+ if (fp)
+ ip_freef(fp);
+
+ } else
+ ip->ip_len -= hlen;
+
+ /*
+ * Switch out to protocol's input routine.
+ */
+ STAT(ipstat.ips_delivered++);
+ switch (ip->ip_p) {
+ case IPPROTO_TCP:
+ tcp_input(m, hlen, (struct socket *)NULL);
+ break;
+ case IPPROTO_UDP:
+ udp_input(m, hlen);
+ break;
+ case IPPROTO_ICMP:
+ icmp_input(m, hlen);
+ break;
+ default:
+ STAT(ipstat.ips_noproto++);
+ m_free(m);
+ }
+ return;
+bad:
+ m_freem(m);
+ return;
+}
+
+/*
+ * Take incoming datagram fragment and try to
+ * reassemble it into whole datagram. If a chain for
+ * reassembly of this datagram already exists, then it
+ * is given as fp; otherwise have to make a chain.
+ */
+static struct ip *
+ip_reass(register struct ipasfrag *ip, register struct ipq *fp)
+{
+ register struct mbuf *m = dtom(ip);
+ register struct ipasfrag *q;
+ int hlen = ip->ip_hl << 2;
+ int i, next;
+
+ DEBUG_CALL("ip_reass");
+ DEBUG_ARG("ip = %lx", (long)ip);
+ DEBUG_ARG("fp = %lx", (long)fp);
+ DEBUG_ARG("m = %lx", (long)m);
+
+ /*
+ * Presence of header sizes in mbufs
+ * would confuse code below.
+ * Fragment m_data is concatenated.
+ */
+ m->m_data += hlen;
+ m->m_len -= hlen;
+
+ /*
+ * If first fragment to arrive, create a reassembly queue.
+ */
+ if (fp == 0) {
+ struct mbuf *t;
+ if ((t = m_get()) == NULL) goto dropfrag;
+ fp = mtod(t, struct ipq *);
+ insque_32(fp, &ipq);
+ fp->ipq_ttl = IPFRAGTTL;
+ fp->ipq_p = ip->ip_p;
+ fp->ipq_id = ip->ip_id;
+ fp->ipq_next = fp->ipq_prev = (ipasfragp_32)fp;
+ fp->ipq_src = ((struct ip *)ip)->ip_src;
+ fp->ipq_dst = ((struct ip *)ip)->ip_dst;
+ q = (struct ipasfrag *)fp;
+ goto insert;
+ }
+
+ /*
+ * Find a segment which begins after this one does.
+ */
+ for (q = (struct ipasfrag *)fp->ipq_next; q != (struct ipasfrag *)fp;
+ q = (struct ipasfrag *)q->ipf_next)
+ if (q->ip_off > ip->ip_off)
+ break;
+
+ /*
+ * If there is a preceding segment, it may provide some of
+ * our data already. If so, drop the data from the incoming
+ * segment. If it provides all of our data, drop us.
+ */
+ if (q->ipf_prev != (ipasfragp_32)fp) {
+ i = ((struct ipasfrag *)(q->ipf_prev))->ip_off +
+ ((struct ipasfrag *)(q->ipf_prev))->ip_len - ip->ip_off;
+ if (i > 0) {
+ if (i >= ip->ip_len)
+ goto dropfrag;
+ m_adj(dtom(ip), i);
+ ip->ip_off += i;
+ ip->ip_len -= i;
+ }
+ }
+
+ /*
+ * While we overlap succeeding segments trim them or,
+ * if they are completely covered, dequeue them.
+ */
+ while (q != (struct ipasfrag *)fp && ip->ip_off + ip->ip_len > q->ip_off) {
+ i = (ip->ip_off + ip->ip_len) - q->ip_off;
+ if (i < q->ip_len) {
+ q->ip_len -= i;
+ q->ip_off += i;
+ m_adj(dtom(q), i);
+ break;
+ }
+ q = (struct ipasfrag *) q->ipf_next;
+ m_freem(dtom((struct ipasfrag *) q->ipf_prev));
+ ip_deq((struct ipasfrag *) q->ipf_prev);
+ }
+
+insert:
+ /*
+ * Stick new segment in its place;
+ * check for complete reassembly.
+ */
+ ip_enq(ip, (struct ipasfrag *) q->ipf_prev);
+ next = 0;
+ for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp;
+ q = (struct ipasfrag *) q->ipf_next) {
+ if (q->ip_off != next)
+ return (0);
+ next += q->ip_len;
+ }
+ if (((struct ipasfrag *)(q->ipf_prev))->ipf_mff & 1)
+ return (0);
+
+ /*
+ * Reassembly is complete; concatenate fragments.
+ */
+ q = (struct ipasfrag *) fp->ipq_next;
+ m = dtom(q);
+
+ q = (struct ipasfrag *) q->ipf_next;
+ while (q != (struct ipasfrag *)fp) {
+ struct mbuf *t;
+ t = dtom(q);
+ q = (struct ipasfrag *) q->ipf_next;
+ m_cat(m, t);
+ }
+
+ /*
+ * Create header for new ip packet by
+ * modifying header of first packet;
+ * dequeue and discard fragment reassembly header.
+ * Make header visible.
+ */
+ ip = (struct ipasfrag *) fp->ipq_next;
+
+ /*
+ * If the fragments concatenated to an mbuf that's
+ * bigger than the total size of the fragment, then and
+ * m_ext buffer was alloced. But fp->ipq_next points to
+ * the old buffer (in the mbuf), so we must point ip
+ * into the new buffer.
+ */
+ if (m->m_flags & M_EXT) {
+ int delta;
+ delta = (char *)ip - m->m_dat;
+ ip = (struct ipasfrag *)(m->m_ext + delta);
+ }
+
+ /* DEBUG_ARG("ip = %lx", (long)ip);
+ * ip=(struct ipasfrag *)m->m_data; */
+
+ ip->ip_len = next;
+ ip->ipf_mff &= ~1;
+ ((struct ip *)ip)->ip_src = fp->ipq_src;
+ ((struct ip *)ip)->ip_dst = fp->ipq_dst;
+ remque_32(fp);
+ (void) m_free(dtom(fp));
+ m = dtom(ip);
+ m->m_len += (ip->ip_hl << 2);
+ m->m_data -= (ip->ip_hl << 2);
+
+ return ((struct ip *)ip);
+
+dropfrag:
+ STAT(ipstat.ips_fragdropped++);
+ m_freem(m);
+ return (0);
+}
+
+/*
+ * Free a fragment reassembly header and all
+ * associated datagrams.
+ */
+static void
+ip_freef(struct ipq *fp)
+{
+ register struct ipasfrag *q, *p;
+
+ for (q = (struct ipasfrag *) fp->ipq_next; q != (struct ipasfrag *)fp;
+ q = p) {
+ p = (struct ipasfrag *) q->ipf_next;
+ ip_deq(q);
+ m_freem(dtom(q));
+ }
+ remque_32(fp);
+ (void) m_free(dtom(fp));
+}
+
+/*
+ * Put an ip fragment on a reassembly chain.
+ * Like insque, but pointers in middle of structure.
+ */
+static void
+ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)
+{
+ DEBUG_CALL("ip_enq");
+ DEBUG_ARG("prev = %lx", (long)prev);
+ p->ipf_prev = (ipasfragp_32) prev;
+ p->ipf_next = prev->ipf_next;
+ ((struct ipasfrag *)(prev->ipf_next))->ipf_prev = (ipasfragp_32) p;
+ prev->ipf_next = (ipasfragp_32) p;
+}
+
+/*
+ * To ip_enq as remque is to insque.
+ */
+static void
+ip_deq(register struct ipasfrag *p)
+{
+ ((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
+ ((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
+}
+
+/*
+ * IP timer processing;
+ * if a timer expires on a reassembly
+ * queue, discard it.
+ */
+void
+ip_slowtimo()
+{
+ register struct ipq *fp;
+
+ DEBUG_CALL("ip_slowtimo");
+
+ fp = (struct ipq *) ipq.next;
+ if (fp == 0)
+ return;
+
+ while (fp != &ipq) {
+ --fp->ipq_ttl;
+ fp = (struct ipq *) fp->next;
+ if (((struct ipq *)(fp->prev))->ipq_ttl == 0) {
+ STAT(ipstat.ips_fragtimeout++);
+ ip_freef((struct ipq *) fp->prev);
+ }
+ }
+}
+
+/*
+ * Do option processing on a datagram,
+ * possibly discarding it if bad options are encountered,
+ * or forwarding it if source-routed.
+ * Returns 1 if packet has been forwarded/freed,
+ * 0 if the packet should be processed further.
+ */
+
+#ifdef notdef
+
+int
+ip_dooptions(m)
+ struct mbuf *m;
+{
+ register struct ip *ip = mtod(m, struct ip *);
+ register u_char *cp;
+ register struct ip_timestamp *ipt;
+ register struct in_ifaddr *ia;
+/* int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; */
+ int opt, optlen, cnt, off, code, type, forward = 0;
+ struct in_addr *sin, dst;
+typedef u_int32_t n_time;
+ n_time ntime;
+
+ dst = ip->ip_dst;
+ cp = (u_char *)(ip + 1);
+ cnt = (ip->ip_hl << 2) - sizeof (struct ip);
+ for (; cnt > 0; cnt -= optlen, cp += optlen) {
+ opt = cp[IPOPT_OPTVAL];
+ if (opt == IPOPT_EOL)
+ break;
+ if (opt == IPOPT_NOP)
+ optlen = 1;
+ else {
+ optlen = cp[IPOPT_OLEN];
+ if (optlen <= 0 || optlen > cnt) {
+ code = &cp[IPOPT_OLEN] - (u_char *)ip;
+ goto bad;
+ }
+ }
+ switch (opt) {
+
+ default:
+ break;
+
+ /*
+ * Source routing with record.
+ * Find interface with current destination address.
+ * If none on this machine then drop if strictly routed,
+ * or do nothing if loosely routed.
+ * Record interface address and bring up next address
+ * component. If strictly routed make sure next
+ * address is on directly accessible net.
+ */
+ case IPOPT_LSRR:
+ case IPOPT_SSRR:
+ if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+ code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+ goto bad;
+ }
+ ipaddr.sin_addr = ip->ip_dst;
+ ia = (struct in_ifaddr *)
+ ifa_ifwithaddr((struct sockaddr *)&ipaddr);
+ if (ia == 0) {
+ if (opt == IPOPT_SSRR) {
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_SRCFAIL;
+ goto bad;
+ }
+ /*
+ * Loose routing, and not at next destination
+ * yet; nothing to do except forward.
+ */
+ break;
+ }
+ off--; / * 0 origin * /
+ if (off > optlen - sizeof(struct in_addr)) {
+ /*
+ * End of source route. Should be for us.
+ */
+ save_rte(cp, ip->ip_src);
+ break;
+ }
+ /*
+ * locate outgoing interface
+ */
+ bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
+ sizeof(ipaddr.sin_addr));
+ if (opt == IPOPT_SSRR) {
+#define INA struct in_ifaddr *
+#define SA struct sockaddr *
+ if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0)
+ ia = (INA)ifa_ifwithnet((SA)&ipaddr);
+ } else
+ ia = ip_rtaddr(ipaddr.sin_addr);
+ if (ia == 0) {
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_SRCFAIL;
+ goto bad;
+ }
+ ip->ip_dst = ipaddr.sin_addr;
+ bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+ (caddr_t)(cp + off), sizeof(struct in_addr));
+ cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+ /*
+ * Let ip_intr's mcast routing check handle mcast pkts
+ */
+ forward = !IN_MULTICAST(ntohl(ip->ip_dst.s_addr));
+ break;
+
+ case IPOPT_RR:
+ if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
+ code = &cp[IPOPT_OFFSET] - (u_char *)ip;
+ goto bad;
+ }
+ /*
+ * If no space remains, ignore.
+ */
+ off--; * 0 origin *
+ if (off > optlen - sizeof(struct in_addr))
+ break;
+ bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
+ sizeof(ipaddr.sin_addr));
+ /*
+ * locate outgoing interface; if we're the destination,
+ * use the incoming interface (should be same).
+ */
+ if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 &&
+ (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) {
+ type = ICMP_UNREACH;
+ code = ICMP_UNREACH_HOST;
+ goto bad;
+ }
+ bcopy((caddr_t)&(IA_SIN(ia)->sin_addr),
+ (caddr_t)(cp + off), sizeof(struct in_addr));
+ cp[IPOPT_OFFSET] += sizeof(struct in_addr);
+ break;
+
+ case IPOPT_TS:
+ code = cp - (u_char *)ip;
+ ipt = (struct ip_timestamp *)cp;
+ if (ipt->ipt_len < 5)
+ goto bad;
+ if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
+ if (++ipt->ipt_oflw == 0)
+ goto bad;
+ break;
+ }
+ sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1);
+ switch (ipt->ipt_flg) {
+
+ case IPOPT_TS_TSONLY:
+ break;
+
+ case IPOPT_TS_TSANDADDR:
+ if (ipt->ipt_ptr + sizeof(n_time) +
+ sizeof(struct in_addr) > ipt->ipt_len)
+ goto bad;
+ ipaddr.sin_addr = dst;
+ ia = (INA)ifaof_ i f p foraddr((SA)&ipaddr,
+ m->m_pkthdr.rcvif);
+ if (ia == 0)
+ continue;
+ bcopy((caddr_t)&IA_SIN(ia)->sin_addr,
+ (caddr_t)sin, sizeof(struct in_addr));
+ ipt->ipt_ptr += sizeof(struct in_addr);
+ break;
+
+ case IPOPT_TS_PRESPEC:
+ if (ipt->ipt_ptr + sizeof(n_time) +
+ sizeof(struct in_addr) > ipt->ipt_len)
+ goto bad;
+ bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr,
+ sizeof(struct in_addr));
+ if (ifa_ifwithaddr((SA)&ipaddr) == 0)
+ continue;
+ ipt->ipt_ptr += sizeof(struct in_addr);
+ break;
+
+ default:
+ goto bad;
+ }
+ ntime = iptime();
+ bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1,
+ sizeof(n_time));
+ ipt->ipt_ptr += sizeof(n_time);
+ }
+ }
+ if (forward) {
+ ip_forward(m, 1);
+ return (1);
+ }
+ }
+ }
+ return (0);
+bad:
+ /* ip->ip_len -= ip->ip_hl << 2; XXX icmp_error adds in hdr length */
+
+/* Not yet */
+ icmp_error(m, type, code, 0, 0);
+
+ STAT(ipstat.ips_badoptions++);
+ return (1);
+}
+
+#endif /* notdef */
+
+/*
+ * Strip out IP options, at higher
+ * level protocol in the kernel.
+ * Second argument is buffer to which options
+ * will be moved, and return value is their length.
+ * (XXX) should be deleted; last arg currently ignored.
+ */
+void
+ip_stripoptions(m, mopt)
+ register struct mbuf *m;
+ struct mbuf *mopt;
+{
+ register int i;
+ struct ip *ip = mtod(m, struct ip *);
+ register caddr_t opts;
+ int olen;
+
+ olen = (ip->ip_hl<<2) - sizeof (struct ip);
+ opts = (caddr_t)(ip + 1);
+ i = m->m_len - (sizeof (struct ip) + olen);
+ memcpy(opts, opts + olen, (unsigned)i);
+ m->m_len -= olen;
+
+ ip->ip_hl = sizeof(struct ip) >> 2;
+}