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-rw-r--r--c/src/libnetworking/netinet/ip_icmp.c710
1 files changed, 710 insertions, 0 deletions
diff --git a/c/src/libnetworking/netinet/ip_icmp.c b/c/src/libnetworking/netinet/ip_icmp.c
new file mode 100644
index 0000000000..a18dacca99
--- /dev/null
+++ b/c/src/libnetworking/netinet/ip_icmp.c
@@ -0,0 +1,710 @@
+/*
+ * 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_icmp.c 8.2 (Berkeley) 1/4/94
+ * $Id$
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/kernel.h>
+#include <sys/socket.h>
+#include <sys/sysctl.h>
+
+#include <net/if.h>
+#include <net/route.h>
+
+#define _IP_VHL
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/in_var.h>
+#include <netinet/ip.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/ip_var.h>
+#include <netinet/icmp_var.h>
+
+/*
+ * ICMP routines: error generation, receive packet processing, and
+ * routines to turnaround packets back to the originator, and
+ * host table maintenance routines.
+ */
+
+ struct icmpstat icmpstat;
+SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RD,
+ &icmpstat, icmpstat, "");
+
+static int icmpmaskrepl = 0;
+SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
+ &icmpmaskrepl, 0, "");
+
+static int icmpbmcastecho = 1;
+SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, &icmpbmcastecho,
+ 0, "");
+
+#ifdef ICMPPRINTFS
+int icmpprintfs = 0;
+#endif
+
+static void icmp_reflect __P((struct mbuf *));
+static void icmp_send __P((struct mbuf *, struct mbuf *));
+static int ip_next_mtu __P((int, int));
+
+extern struct protosw inetsw[];
+
+/*
+ * Generate an error packet of type error
+ * in response to bad packet ip.
+ */
+void
+icmp_error(n, type, code, dest, destifp)
+ struct mbuf *n;
+ int type, code;
+ n_long dest;
+ struct ifnet *destifp;
+{
+ register struct ip *oip = mtod(n, struct ip *), *nip;
+ register unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2;
+ register struct icmp *icp;
+ register struct mbuf *m;
+ unsigned icmplen;
+
+#ifdef ICMPPRINTFS
+ if (icmpprintfs)
+ printf("icmp_error(%p, %x, %d)\n", oip, type, code);
+#endif
+ if (type != ICMP_REDIRECT)
+ icmpstat.icps_error++;
+ /*
+ * Don't send error if not the first fragment of message.
+ * Don't error if the old packet protocol was ICMP
+ * error message, only known informational types.
+ */
+ if (oip->ip_off &~ (IP_MF|IP_DF))
+ goto freeit;
+ if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
+ n->m_len >= oiplen + ICMP_MINLEN &&
+ !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
+ icmpstat.icps_oldicmp++;
+ goto freeit;
+ }
+ /* Don't send error in response to a multicast or broadcast packet */
+ if (n->m_flags & (M_BCAST|M_MCAST))
+ goto freeit;
+ /*
+ * First, formulate icmp message
+ */
+ m = m_gethdr(M_DONTWAIT, MT_HEADER);
+ if (m == NULL)
+ goto freeit;
+ icmplen = oiplen + min(8, oip->ip_len);
+ m->m_len = icmplen + ICMP_MINLEN;
+ MH_ALIGN(m, m->m_len);
+ icp = mtod(m, struct icmp *);
+ if ((u_int)type > ICMP_MAXTYPE)
+ panic("icmp_error");
+ icmpstat.icps_outhist[type]++;
+ icp->icmp_type = type;
+ if (type == ICMP_REDIRECT)
+ icp->icmp_gwaddr.s_addr = dest;
+ else {
+ icp->icmp_void = 0;
+ /*
+ * The following assignments assume an overlay with the
+ * zeroed icmp_void field.
+ */
+ if (type == ICMP_PARAMPROB) {
+ icp->icmp_pptr = code;
+ code = 0;
+ } else if (type == ICMP_UNREACH &&
+ code == ICMP_UNREACH_NEEDFRAG && destifp) {
+ icp->icmp_nextmtu = htons(destifp->if_mtu);
+ }
+ }
+
+ icp->icmp_code = code;
+ bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen);
+ nip = &icp->icmp_ip;
+ nip->ip_len = htons((u_short)(nip->ip_len + oiplen));
+
+ /*
+ * Now, copy old ip header (without options)
+ * in front of icmp message.
+ */
+ if (m->m_data - sizeof(struct ip) < m->m_pktdat)
+ panic("icmp len");
+ m->m_data -= sizeof(struct ip);
+ m->m_len += sizeof(struct ip);
+ m->m_pkthdr.len = m->m_len;
+ m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
+ nip = mtod(m, struct ip *);
+ bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
+ nip->ip_len = m->m_len;
+ nip->ip_vhl = IP_VHL_BORING;
+ nip->ip_p = IPPROTO_ICMP;
+ nip->ip_tos = 0;
+ icmp_reflect(m);
+
+freeit:
+ m_freem(n);
+}
+
+static struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET };
+static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET };
+static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET };
+
+/*
+ * Process a received ICMP message.
+ */
+void
+icmp_input(m, hlen)
+ register struct mbuf *m;
+ int hlen;
+{
+ register struct icmp *icp;
+ register struct ip *ip = mtod(m, struct ip *);
+ int icmplen = ip->ip_len;
+ register int i;
+ struct in_ifaddr *ia;
+ void (*ctlfunc) __P((int, struct sockaddr *, void *));
+ int code;
+
+ /*
+ * Locate icmp structure in mbuf, and check
+ * that not corrupted and of at least minimum length.
+ */
+#ifdef ICMPPRINTFS
+ if (icmpprintfs) {
+ char buf[4 * sizeof "123"];
+ strcpy(buf, inet_ntoa(ip->ip_src));
+ printf("icmp_input from %s to %s, len %d\n",
+ buf, inet_ntoa(ip->ip_dst), icmplen);
+ }
+#endif
+ if (icmplen < ICMP_MINLEN) {
+ icmpstat.icps_tooshort++;
+ goto freeit;
+ }
+ i = hlen + min(icmplen, ICMP_ADVLENMIN);
+ if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
+ icmpstat.icps_tooshort++;
+ return;
+ }
+ ip = mtod(m, struct ip *);
+ m->m_len -= hlen;
+ m->m_data += hlen;
+ icp = mtod(m, struct icmp *);
+ if (in_cksum(m, icmplen)) {
+ icmpstat.icps_checksum++;
+ goto freeit;
+ }
+ m->m_len += hlen;
+ m->m_data -= hlen;
+
+#ifdef ICMPPRINTFS
+ if (icmpprintfs)
+ printf("icmp_input, type %d code %d\n", icp->icmp_type,
+ icp->icmp_code);
+#endif
+
+ /*
+ * Message type specific processing.
+ */
+ if (icp->icmp_type > ICMP_MAXTYPE)
+ goto raw;
+ icmpstat.icps_inhist[icp->icmp_type]++;
+ code = icp->icmp_code;
+ switch (icp->icmp_type) {
+
+ case ICMP_UNREACH:
+ switch (code) {
+ case ICMP_UNREACH_NET:
+ case ICMP_UNREACH_HOST:
+ case ICMP_UNREACH_PROTOCOL:
+ case ICMP_UNREACH_PORT:
+ case ICMP_UNREACH_SRCFAIL:
+ code += PRC_UNREACH_NET;
+ break;
+
+ case ICMP_UNREACH_NEEDFRAG:
+ code = PRC_MSGSIZE;
+ break;
+
+ case ICMP_UNREACH_NET_UNKNOWN:
+ case ICMP_UNREACH_NET_PROHIB:
+ case ICMP_UNREACH_TOSNET:
+ code = PRC_UNREACH_NET;
+ break;
+
+ case ICMP_UNREACH_HOST_UNKNOWN:
+ case ICMP_UNREACH_ISOLATED:
+ case ICMP_UNREACH_HOST_PROHIB:
+ case ICMP_UNREACH_TOSHOST:
+ code = PRC_UNREACH_HOST;
+ break;
+
+ case ICMP_UNREACH_FILTER_PROHIB:
+ case ICMP_UNREACH_HOST_PRECEDENCE:
+ case ICMP_UNREACH_PRECEDENCE_CUTOFF:
+ code = PRC_UNREACH_PORT;
+ break;
+
+ default:
+ goto badcode;
+ }
+ goto deliver;
+
+ case ICMP_TIMXCEED:
+ if (code > 1)
+ goto badcode;
+ code += PRC_TIMXCEED_INTRANS;
+ goto deliver;
+
+ case ICMP_PARAMPROB:
+ if (code > 1)
+ goto badcode;
+ code = PRC_PARAMPROB;
+ goto deliver;
+
+ case ICMP_SOURCEQUENCH:
+ if (code)
+ goto badcode;
+ code = PRC_QUENCH;
+ deliver:
+ /*
+ * Problem with datagram; advise higher level routines.
+ */
+ if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
+ IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
+ icmpstat.icps_badlen++;
+ goto freeit;
+ }
+ NTOHS(icp->icmp_ip.ip_len);
+ /* Discard ICMP's in response to multicast packets */
+ if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
+ goto badcode;
+#ifdef ICMPPRINTFS
+ if (icmpprintfs)
+ printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
+#endif
+ icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
+#if 1
+ /*
+ * MTU discovery:
+ * If we got a needfrag and there is a host route to the
+ * original destination, and the MTU is not locked, then
+ * set the MTU in the route to the suggested new value
+ * (if given) and then notify as usual. The ULPs will
+ * notice that the MTU has changed and adapt accordingly.
+ * If no new MTU was suggested, then we guess a new one
+ * less than the current value. If the new MTU is
+ * unreasonably small (arbitrarily set at 296), then
+ * we reset the MTU to the interface value and enable the
+ * lock bit, indicating that we are no longer doing MTU
+ * discovery.
+ */
+ if (code == PRC_MSGSIZE) {
+ struct rtentry *rt;
+ int mtu;
+
+ rt = rtalloc1((struct sockaddr *)&icmpsrc, 0,
+ RTF_CLONING | RTF_PRCLONING);
+ if (rt && (rt->rt_flags & RTF_HOST)
+ && !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
+ mtu = ntohs(icp->icmp_nextmtu);
+ if (!mtu)
+ mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu,
+ 1);
+#ifdef DEBUG_MTUDISC
+ printf("MTU for %s reduced to %d\n",
+ inet_ntoa(icmpsrc.sin_addr), mtu);
+#endif
+ if (mtu < 296) {
+ /* rt->rt_rmx.rmx_mtu =
+ rt->rt_ifp->if_mtu; */
+ rt->rt_rmx.rmx_locks |= RTV_MTU;
+ } else if (rt->rt_rmx.rmx_mtu > mtu) {
+ rt->rt_rmx.rmx_mtu = mtu;
+ }
+ }
+ if (rt)
+ RTFREE(rt);
+ }
+
+#endif
+ ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
+ if (ctlfunc)
+ (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
+ (void *)&icp->icmp_ip);
+ break;
+
+ badcode:
+ icmpstat.icps_badcode++;
+ break;
+
+ case ICMP_ECHO:
+ if (!icmpbmcastecho
+ && (m->m_flags & (M_MCAST | M_BCAST)) != 0
+ && IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
+ icmpstat.icps_bmcastecho++;
+ break;
+ }
+ icp->icmp_type = ICMP_ECHOREPLY;
+ goto reflect;
+
+ case ICMP_TSTAMP:
+ if (!icmpbmcastecho
+ && (m->m_flags & (M_MCAST | M_BCAST)) != 0
+ && IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
+ icmpstat.icps_bmcasttstamp++;
+ break;
+ }
+ if (icmplen < ICMP_TSLEN) {
+ icmpstat.icps_badlen++;
+ break;
+ }
+ icp->icmp_type = ICMP_TSTAMPREPLY;
+ icp->icmp_rtime = iptime();
+ icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
+ goto reflect;
+
+ case ICMP_MASKREQ:
+#define satosin(sa) ((struct sockaddr_in *)(sa))
+ if (icmpmaskrepl == 0)
+ break;
+ /*
+ * We are not able to respond with all ones broadcast
+ * unless we receive it over a point-to-point interface.
+ */
+ if (icmplen < ICMP_MASKLEN)
+ break;
+ switch (ip->ip_dst.s_addr) {
+
+ case INADDR_BROADCAST:
+ case INADDR_ANY:
+ icmpdst.sin_addr = ip->ip_src;
+ break;
+
+ default:
+ icmpdst.sin_addr = ip->ip_dst;
+ }
+ ia = (struct in_ifaddr *)ifaof_ifpforaddr(
+ (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
+ if (ia == 0)
+ break;
+ if (ia->ia_ifp == 0)
+ break;
+ icp->icmp_type = ICMP_MASKREPLY;
+ icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
+ if (ip->ip_src.s_addr == 0) {
+ if (ia->ia_ifp->if_flags & IFF_BROADCAST)
+ ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
+ else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
+ ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
+ }
+reflect:
+ ip->ip_len += hlen; /* since ip_input deducts this */
+ icmpstat.icps_reflect++;
+ icmpstat.icps_outhist[icp->icmp_type]++;
+ icmp_reflect(m);
+ return;
+
+ case ICMP_REDIRECT:
+ if (code > 3)
+ goto badcode;
+ if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
+ IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
+ icmpstat.icps_badlen++;
+ break;
+ }
+ /*
+ * Short circuit routing redirects to force
+ * immediate change in the kernel's routing
+ * tables. The message is also handed to anyone
+ * listening on a raw socket (e.g. the routing
+ * daemon for use in updating its tables).
+ */
+ icmpgw.sin_addr = ip->ip_src;
+ icmpdst.sin_addr = icp->icmp_gwaddr;
+#ifdef ICMPPRINTFS
+ if (icmpprintfs) {
+ char buf[4 * sizeof "123"];
+ strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
+
+ printf("redirect dst %s to %s\n",
+ buf, inet_ntoa(icp->icmp_gwaddr));
+ }
+#endif
+ icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
+ rtredirect((struct sockaddr *)&icmpsrc,
+ (struct sockaddr *)&icmpdst,
+ (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
+ (struct sockaddr *)&icmpgw, (struct rtentry **)0);
+ pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
+ break;
+
+ /*
+ * No kernel processing for the following;
+ * just fall through to send to raw listener.
+ */
+ case ICMP_ECHOREPLY:
+ case ICMP_ROUTERADVERT:
+ case ICMP_ROUTERSOLICIT:
+ case ICMP_TSTAMPREPLY:
+ case ICMP_IREQREPLY:
+ case ICMP_MASKREPLY:
+ default:
+ break;
+ }
+
+raw:
+ rip_input(m, hlen);
+ return;
+
+freeit:
+ m_freem(m);
+}
+
+/*
+ * Reflect the ip packet back to the source
+ */
+static void
+icmp_reflect(m)
+ struct mbuf *m;
+{
+ register struct ip *ip = mtod(m, struct ip *);
+ register struct in_ifaddr *ia;
+ struct in_addr t;
+ struct mbuf *opts = 0;
+ int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
+
+ if (!in_canforward(ip->ip_src) &&
+ ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) !=
+ (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
+ m_freem(m); /* Bad return address */
+ goto done; /* Ip_output() will check for broadcast */
+ }
+ t = ip->ip_dst;
+ ip->ip_dst = ip->ip_src;
+ /*
+ * If the incoming packet was addressed directly to us,
+ * use dst as the src for the reply. Otherwise (broadcast
+ * or anonymous), use the address which corresponds
+ * to the incoming interface.
+ */
+ for (ia = in_ifaddr; ia; ia = ia->ia_next) {
+ if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
+ break;
+ if (ia->ia_ifp && (ia->ia_ifp->if_flags & IFF_BROADCAST) &&
+ t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr)
+ break;
+ }
+ icmpdst.sin_addr = t;
+ if ((ia == (struct in_ifaddr *)0) && m->m_pkthdr.rcvif)
+ ia = (struct in_ifaddr *)ifaof_ifpforaddr(
+ (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
+ /*
+ * The following happens if the packet was not addressed to us,
+ * and was received on an interface with no IP address.
+ */
+ if (ia == (struct in_ifaddr *)0)
+ ia = in_ifaddr;
+ t = IA_SIN(ia)->sin_addr;
+ ip->ip_src = t;
+ ip->ip_ttl = MAXTTL;
+
+ if (optlen > 0) {
+ register u_char *cp;
+ int opt, cnt;
+ u_int len;
+
+ /*
+ * Retrieve any source routing from the incoming packet;
+ * add on any record-route or timestamp options.
+ */
+ cp = (u_char *) (ip + 1);
+ if ((opts = ip_srcroute()) == 0 &&
+ (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) {
+ opts->m_len = sizeof(struct in_addr);
+ mtod(opts, struct in_addr *)->s_addr = 0;
+ }
+ if (opts) {
+#ifdef ICMPPRINTFS
+ if (icmpprintfs)
+ printf("icmp_reflect optlen %d rt %d => ",
+ optlen, opts->m_len);
+#endif
+ for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
+ opt = cp[IPOPT_OPTVAL];
+ if (opt == IPOPT_EOL)
+ break;
+ if (opt == IPOPT_NOP)
+ len = 1;
+ else {
+ len = cp[IPOPT_OLEN];
+ if (len <= 0 || len > cnt)
+ break;
+ }
+ /*
+ * Should check for overflow, but it "can't happen"
+ */
+ if (opt == IPOPT_RR || opt == IPOPT_TS ||
+ opt == IPOPT_SECURITY) {
+ bcopy((caddr_t)cp,
+ mtod(opts, caddr_t) + opts->m_len, len);
+ opts->m_len += len;
+ }
+ }
+ /* Terminate & pad, if necessary */
+ cnt = opts->m_len % 4;
+ if (cnt) {
+ for (; cnt < 4; cnt++) {
+ *(mtod(opts, caddr_t) + opts->m_len) =
+ IPOPT_EOL;
+ opts->m_len++;
+ }
+ }
+#ifdef ICMPPRINTFS
+ if (icmpprintfs)
+ printf("%d\n", opts->m_len);
+#endif
+ }
+ /*
+ * Now strip out original options by copying rest of first
+ * mbuf's data back, and adjust the IP length.
+ */
+ ip->ip_len -= optlen;
+ ip->ip_vhl = IP_VHL_BORING;
+ m->m_len -= optlen;
+ if (m->m_flags & M_PKTHDR)
+ m->m_pkthdr.len -= optlen;
+ optlen += sizeof(struct ip);
+ bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
+ (unsigned)(m->m_len - sizeof(struct ip)));
+ }
+ m->m_flags &= ~(M_BCAST|M_MCAST);
+ icmp_send(m, opts);
+done:
+ if (opts)
+ (void)m_free(opts);
+}
+
+/*
+ * Send an icmp packet back to the ip level,
+ * after supplying a checksum.
+ */
+static void
+icmp_send(m, opts)
+ register struct mbuf *m;
+ struct mbuf *opts;
+{
+ register struct ip *ip = mtod(m, struct ip *);
+ register int hlen;
+ register struct icmp *icp;
+ struct route ro;
+
+ hlen = IP_VHL_HL(ip->ip_vhl) << 2;
+ m->m_data += hlen;
+ m->m_len -= hlen;
+ icp = mtod(m, struct icmp *);
+ icp->icmp_cksum = 0;
+ icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
+ m->m_data -= hlen;
+ m->m_len += hlen;
+#ifdef ICMPPRINTFS
+ if (icmpprintfs) {
+ char buf[4 * sizeof "123"];
+ strcpy(buf, inet_ntoa(ip->ip_dst));
+ printf("icmp_send dst %s src %s\n",
+ buf, inet_ntoa(ip->ip_src));
+ }
+#endif
+ bzero(&ro, sizeof ro);
+ (void) ip_output(m, opts, &ro, 0, NULL);
+ if (ro.ro_rt)
+ RTFREE(ro.ro_rt);
+}
+
+n_time
+iptime()
+{
+ struct timeval atv;
+ u_long t;
+
+ microtime(&atv);
+ t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
+ return (htonl(t));
+}
+
+#if 1
+/*
+ * Return the next larger or smaller MTU plateau (table from RFC 1191)
+ * given current value MTU. If DIR is less than zero, a larger plateau
+ * is returned; otherwise, a smaller value is returned.
+ */
+static int
+ip_next_mtu(mtu, dir)
+ int mtu;
+ int dir;
+{
+ static int mtutab[] = {
+ 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296,
+ 68, 0
+ };
+ int i;
+
+ for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) {
+ if (mtu >= mtutab[i])
+ break;
+ }
+
+ if (dir < 0) {
+ if (i == 0) {
+ return 0;
+ } else {
+ return mtutab[i - 1];
+ }
+ } else {
+ if (mtutab[i] == 0) {
+ return 0;
+ } else if(mtu > mtutab[i]) {
+ return mtutab[i];
+ } else {
+ return mtutab[i + 1];
+ }
+ }
+}
+#endif