2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
34 * $FreeBSD: src/sys/netinet/ip_icmp.c,v 1.39.2.19 2003/01/24 05:11:34 sam Exp $
35 * $DragonFly: src/sys/netinet/ip_icmp.c,v 1.22 2005/03/06 05:09:25 hsu Exp $
38 #include "opt_ipsec.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
46 #include <sys/kernel.h>
47 #include <sys/sysctl.h>
48 #include <sys/in_cksum.h>
50 #include <machine/stdarg.h>
53 #include <net/if_types.h>
54 #include <net/route.h>
57 #include <netinet/in.h>
58 #include <netinet/in_systm.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip.h>
61 #include <netinet/ip_icmp.h>
62 #include <netinet/ip_var.h>
63 #include <netinet/icmp_var.h>
66 #include <netinet6/ipsec.h>
67 #include <netproto/key/key.h>
71 #include <netproto/ipsec/ipsec.h>
72 #include <netproto/ipsec/key.h>
77 * ICMP routines: error generation, receive packet processing, and
78 * routines to turnaround packets back to the originator, and
79 * host table maintenance routines.
82 struct icmpstat icmpstat;
83 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW,
84 &icmpstat, icmpstat, "");
86 static int icmpmaskrepl = 0;
87 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
88 &icmpmaskrepl, 0, "");
90 static int drop_redirect = 0;
91 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW,
92 &drop_redirect, 0, "");
94 static int log_redirect = 0;
95 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
96 &log_redirect, 0, "");
101 * ICMP error-response bandwidth limiting sysctl. If not enabled, sysctl
102 * variable content is -1 and read-only.
105 static int icmplim = 200;
106 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
110 static int icmplim = -1;
111 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RD,
116 static int icmplim_output = 1;
117 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
118 &icmplim_output, 0, "");
121 * ICMP broadcast echo sysctl
124 static int icmpbmcastecho = 0;
125 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
126 &icmpbmcastecho, 0, "");
133 static void icmp_reflect (struct mbuf *);
134 static void icmp_send (struct mbuf *, struct mbuf *, struct route *);
136 extern struct protosw inetsw[];
139 * Generate an error packet of type error
140 * in response to bad packet ip.
143 icmp_error(n, type, code, dest, destifp)
147 struct ifnet *destifp;
149 struct ip *oip = mtod(n, struct ip *), *nip;
150 unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2;
157 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
159 if (type != ICMP_REDIRECT)
160 icmpstat.icps_error++;
162 * Don't send error if the original packet was encrypted.
163 * Don't send error if not the first fragment of message.
164 * Don't error if the old packet protocol was ICMP
165 * error message, only known informational types.
167 if (n->m_flags & M_DECRYPTED)
169 if (oip->ip_off &~ (IP_MF|IP_DF))
171 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
172 n->m_len >= oiplen + ICMP_MINLEN &&
173 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
174 icmpstat.icps_oldicmp++;
177 /* Don't send error in response to a multicast or broadcast packet */
178 if (n->m_flags & (M_BCAST|M_MCAST))
181 * First, formulate icmp message
183 m = m_gethdr(MB_DONTWAIT, MT_HEADER);
186 icmplen = min(oiplen + 8, oip->ip_len);
187 if (icmplen < sizeof(struct ip))
188 panic("icmp_error: bad length");
189 m->m_len = icmplen + ICMP_MINLEN;
190 MH_ALIGN(m, m->m_len);
191 icp = mtod(m, struct icmp *);
192 if ((u_int)type > ICMP_MAXTYPE)
194 icmpstat.icps_outhist[type]++;
195 icp->icmp_type = type;
196 if (type == ICMP_REDIRECT)
197 icp->icmp_gwaddr.s_addr = dest;
201 * The following assignments assume an overlay with the
202 * zeroed icmp_void field.
204 if (type == ICMP_PARAMPROB) {
205 icp->icmp_pptr = code;
207 } else if (type == ICMP_UNREACH &&
208 code == ICMP_UNREACH_NEEDFRAG && destifp) {
209 icp->icmp_nextmtu = htons(destifp->if_mtu);
213 icp->icmp_code = code;
214 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
218 * Convert fields to network representation.
220 nip->ip_len = htons(nip->ip_len);
221 nip->ip_off = htons(nip->ip_off);
224 * Now, copy old ip header (without options)
225 * in front of icmp message.
227 if (m->m_data - sizeof(struct ip) < m->m_pktdat)
229 m->m_data -= sizeof(struct ip);
230 m->m_len += sizeof(struct ip);
231 m->m_pkthdr.len = m->m_len;
232 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
233 nip = mtod(m, struct ip *);
234 bcopy(oip, nip, sizeof(struct ip));
235 nip->ip_len = m->m_len;
236 nip->ip_vhl = IP_VHL_BORING;
237 nip->ip_p = IPPROTO_ICMP;
239 m->m_pkthdr.fw_flags |= n->m_pkthdr.fw_flags & PF_MBUF_GENERATED;
247 * Process a received ICMP message.
250 icmp_input(struct mbuf *m, ...)
252 struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET };
253 struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET };
254 struct sockaddr_in icmpgw = { sizeof(struct sockaddr_in), AF_INET };
256 struct in_ifaddr *ia;
257 struct ip *ip = mtod(m, struct ip *);
258 void (*ctlfunc) (int, struct sockaddr *, void *);
259 int icmplen = ip->ip_len;
261 int code, off, proto;
265 off = __va_arg(ap, int);
266 proto = __va_arg(ap, int);
272 * Locate icmp structure in mbuf, and check
273 * that not corrupted and of at least minimum length.
277 char buf[sizeof "aaa.bbb.ccc.ddd"];
279 strcpy(buf, inet_ntoa(ip->ip_src));
280 printf("icmp_input from %s to %s, len %d\n",
281 buf, inet_ntoa(ip->ip_dst), icmplen);
284 if (icmplen < ICMP_MINLEN) {
285 icmpstat.icps_tooshort++;
288 i = hlen + min(icmplen, ICMP_ADVLENMIN);
289 if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
290 icmpstat.icps_tooshort++;
293 ip = mtod(m, struct ip *);
296 icp = mtod(m, struct icmp *);
297 if (in_cksum(m, icmplen)) {
298 icmpstat.icps_checksum++;
304 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
306 * Deliver very specific ICMP type only.
308 switch (icp->icmp_type) {
319 printf("icmp_input, type %d code %d\n", icp->icmp_type,
324 * Message type specific processing.
326 if (icp->icmp_type > ICMP_MAXTYPE)
328 icmpstat.icps_inhist[icp->icmp_type]++;
329 code = icp->icmp_code;
330 switch (icp->icmp_type) {
334 case ICMP_UNREACH_NET:
335 case ICMP_UNREACH_HOST:
336 case ICMP_UNREACH_SRCFAIL:
337 case ICMP_UNREACH_NET_UNKNOWN:
338 case ICMP_UNREACH_HOST_UNKNOWN:
339 case ICMP_UNREACH_ISOLATED:
340 case ICMP_UNREACH_TOSNET:
341 case ICMP_UNREACH_TOSHOST:
342 case ICMP_UNREACH_HOST_PRECEDENCE:
343 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
344 code = PRC_UNREACH_NET;
347 case ICMP_UNREACH_NEEDFRAG:
352 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
353 * Treat subcodes 2,3 as immediate RST
355 case ICMP_UNREACH_PROTOCOL:
356 case ICMP_UNREACH_PORT:
357 code = PRC_UNREACH_PORT;
360 case ICMP_UNREACH_NET_PROHIB:
361 case ICMP_UNREACH_HOST_PROHIB:
362 case ICMP_UNREACH_FILTER_PROHIB:
363 code = PRC_UNREACH_ADMIN_PROHIB;
374 code += PRC_TIMXCEED_INTRANS;
380 code = PRC_PARAMPROB;
383 case ICMP_SOURCEQUENCH:
389 * Problem with datagram; advise higher level routines.
391 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
392 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
393 icmpstat.icps_badlen++;
396 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
397 /* Discard ICMP's in response to multicast packets */
398 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
402 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
404 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
408 * If we got a needfrag and there is a host route to the
409 * original destination, and the MTU is not locked, then
410 * set the MTU in the route to the suggested new value
411 * (if given) and then notify as usual. The ULPs will
412 * notice that the MTU has changed and adapt accordingly.
413 * If no new MTU was suggested, then we guess a new one
414 * less than the current value. If the new MTU is
415 * unreasonably small (arbitrarily set at 296), then
416 * we reset the MTU to the interface value and enable the
417 * lock bit, indicating that we are no longer doing MTU
420 if (code == PRC_MSGSIZE) {
424 rt = rtpurelookup((struct sockaddr *)&icmpsrc);
425 if (rt != NULL && (rt->rt_flags & RTF_HOST) &&
426 !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
427 mtu = ntohs(icp->icmp_nextmtu);
429 mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu,
432 printf("MTU for %s reduced to %d\n",
433 inet_ntoa(icmpsrc.sin_addr), mtu);
436 /* rt->rt_rmx.rmx_mtu =
437 rt->rt_ifp->if_mtu; */
438 rt->rt_rmx.rmx_locks |= RTV_MTU;
439 } else if (rt->rt_rmx.rmx_mtu > mtu) {
440 rt->rt_rmx.rmx_mtu = mtu;
448 * XXX if the packet contains [IPv4 AH TCP], we can't make a
449 * notification to TCP layer.
451 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
453 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
458 icmpstat.icps_badcode++;
463 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
464 icmpstat.icps_bmcastecho++;
467 icp->icmp_type = ICMP_ECHOREPLY;
469 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
477 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
478 icmpstat.icps_bmcasttstamp++;
481 if (icmplen < ICMP_TSLEN) {
482 icmpstat.icps_badlen++;
485 icp->icmp_type = ICMP_TSTAMPREPLY;
486 icp->icmp_rtime = iptime();
487 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
489 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
496 if (icmpmaskrepl == 0)
499 * We are not able to respond with all ones broadcast
500 * unless we receive it over a point-to-point interface.
502 if (icmplen < ICMP_MASKLEN)
504 switch (ip->ip_dst.s_addr) {
506 case INADDR_BROADCAST:
508 icmpdst.sin_addr = ip->ip_src;
512 icmpdst.sin_addr = ip->ip_dst;
514 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
515 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
520 icp->icmp_type = ICMP_MASKREPLY;
521 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
522 if (ip->ip_src.s_addr == 0) {
523 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
524 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
525 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
526 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
529 ip->ip_len += hlen; /* since ip_input deducts this */
530 icmpstat.icps_reflect++;
531 icmpstat.icps_outhist[icp->icmp_type]++;
539 src = ntohl(ip->ip_src.s_addr);
540 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
541 gw = ntohl(icp->icmp_gwaddr.s_addr);
542 printf("icmp redirect from %d.%d.%d.%d: "
543 "%d.%d.%d.%d => %d.%d.%d.%d\n",
544 (int)(src >> 24), (int)((src >> 16) & 0xff),
545 (int)((src >> 8) & 0xff), (int)(src & 0xff),
546 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
547 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
548 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
549 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
555 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
556 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
557 icmpstat.icps_badlen++;
561 * Short circuit routing redirects to force
562 * immediate change in the kernel's routing
563 * tables. The message is also handed to anyone
564 * listening on a raw socket (e.g. the routing
565 * daemon for use in updating its tables).
567 icmpgw.sin_addr = ip->ip_src;
568 icmpdst.sin_addr = icp->icmp_gwaddr;
571 char buf[sizeof "aaa.bbb.ccc.ddd"];
573 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
574 printf("redirect dst %s to %s\n",
575 buf, inet_ntoa(icp->icmp_gwaddr));
578 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
579 rtredirect((struct sockaddr *)&icmpsrc,
580 (struct sockaddr *)&icmpdst,
581 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
582 (struct sockaddr *)&icmpgw);
583 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
585 key_sa_routechange((struct sockaddr *)&icmpsrc);
590 * No kernel processing for the following;
591 * just fall through to send to raw listener.
594 case ICMP_ROUTERADVERT:
595 case ICMP_ROUTERSOLICIT:
596 case ICMP_TSTAMPREPLY:
604 rip_input(m, off, proto);
612 * Reflect the ip packet back to the source
618 struct ip *ip = mtod(m, struct ip *);
620 struct in_ifaddr *ia;
622 struct mbuf *opts = 0;
623 int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
624 struct route *ro = NULL, rt;
626 if (!in_canforward(ip->ip_src) &&
627 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) !=
628 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
629 m_freem(m); /* Bad return address */
630 icmpstat.icps_badaddr++;
631 goto done; /* Ip_output() will check for broadcast */
634 ip->ip_dst = ip->ip_src;
636 bzero(ro, sizeof *ro);
638 * If the incoming packet was addressed directly to us,
639 * use dst as the src for the reply. Otherwise (broadcast
640 * or anonymous), use the address which corresponds
641 * to the incoming interface.
643 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash)
644 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
646 if (m->m_pkthdr.rcvif != NULL &&
647 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
648 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
649 if (ifa->ifa_addr->sa_family != AF_INET)
652 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
657 ia = ip_rtaddr(ip->ip_dst, ro);
658 /* We need a route to do anything useful. */
661 icmpstat.icps_noroute++;
665 t = IA_SIN(ia)->sin_addr;
667 ip->ip_ttl = ip_defttl;
675 * Retrieve any source routing from the incoming packet;
676 * add on any record-route or timestamp options.
678 cp = (u_char *) (ip + 1);
679 if ((opts = ip_srcroute()) == 0 &&
680 (opts = m_gethdr(MB_DONTWAIT, MT_HEADER))) {
681 opts->m_len = sizeof(struct in_addr);
682 mtod(opts, struct in_addr *)->s_addr = 0;
687 printf("icmp_reflect optlen %d rt %d => ",
688 optlen, opts->m_len);
690 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
691 opt = cp[IPOPT_OPTVAL];
692 if (opt == IPOPT_EOL)
694 if (opt == IPOPT_NOP)
697 if (cnt < IPOPT_OLEN + sizeof *cp)
699 len = cp[IPOPT_OLEN];
700 if (len < IPOPT_OLEN + sizeof *cp ||
705 * Should check for overflow, but it
708 if (opt == IPOPT_RR || opt == IPOPT_TS ||
709 opt == IPOPT_SECURITY) {
711 mtod(opts, caddr_t) + opts->m_len,
716 /* Terminate & pad, if necessary */
717 cnt = opts->m_len % 4;
719 for (; cnt < 4; cnt++) {
720 *(mtod(opts, caddr_t) + opts->m_len) =
727 printf("%d\n", opts->m_len);
731 * Now strip out original options by copying rest of first
732 * mbuf's data back, and adjust the IP length.
734 ip->ip_len -= optlen;
735 ip->ip_vhl = IP_VHL_BORING;
737 if (m->m_flags & M_PKTHDR)
738 m->m_pkthdr.len -= optlen;
739 optlen += sizeof(struct ip);
740 bcopy((caddr_t)ip + optlen, ip + 1,
741 m->m_len - sizeof(struct ip));
743 m->m_pkthdr.fw_flags &= PF_MBUF_GENERATED;
744 m->m_flags &= ~(M_BCAST|M_MCAST);
745 icmp_send(m, opts, ro);
754 * Send an icmp packet back to the ip level,
755 * after supplying a checksum.
758 icmp_send(m, opts, rt)
763 struct ip *ip = mtod(m, struct ip *);
767 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
770 icp = mtod(m, struct icmp *);
772 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
775 m->m_pkthdr.rcvif = (struct ifnet *)0;
778 char buf[sizeof "aaa.bbb.ccc.ddd"];
780 strcpy(buf, inet_ntoa(ip->ip_dst));
781 printf("icmp_send dst %s src %s\n", buf, inet_ntoa(ip->ip_src));
784 ip_output(m, opts, rt, 0, NULL, NULL);
794 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
800 * Return the next larger or smaller MTU plateau (table from RFC 1191)
801 * given current value MTU. If DIR is less than zero, a larger plateau
802 * is returned; otherwise, a smaller value is returned.
805 ip_next_mtu(int mtu, int dir)
807 static int mtutab[] = {
808 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296,
813 for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) {
814 if (mtu >= mtutab[i])
822 return mtutab[i - 1];
825 if (mtutab[i] == 0) {
827 } else if(mtu > mtutab[i]) {
830 return mtutab[i + 1];
838 * badport_bandlim() - check for ICMP bandwidth limit
840 * Return 0 if it is ok to send an ICMP error response, -1 if we have
841 * hit our bandwidth limit and it is not ok.
843 * If icmplim is <= 0, the feature is disabled and 0 is returned.
845 * For now we separate the TCP and UDP subsystems w/ different 'which'
846 * values. We may eventually remove this separation (and simplify the
849 * Note that the printing of the error message is delayed so we can
850 * properly print the icmp error rate that the system was trying to do
851 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
852 * the 'final' error, but it doesn't make sense to solve the printing
853 * delay with more complex code.
856 badport_bandlim(int which)
858 static int lticks[BANDLIM_MAX + 1];
859 static int lpackets[BANDLIM_MAX + 1];
861 const char *bandlimittype[] = {
862 "Limiting icmp unreach response",
863 "Limiting icmp ping response",
864 "Limiting icmp tstamp response",
865 "Limiting closed port RST response",
866 "Limiting open port RST response"
870 * Return ok status if feature disabled or argument out of
874 if (icmplim <= 0 || which > BANDLIM_MAX || which < 0)
876 dticks = ticks - lticks[which];
879 * reset stats when cumulative dt exceeds one second.
882 if ((unsigned int)dticks > hz) {
883 if (lpackets[which] > icmplim && icmplim_output) {
884 printf("%s from %d to %d packets per second\n",
885 bandlimittype[which],
890 lticks[which] = ticks;
898 if (++lpackets[which] > icmplim) {