2 * Copyright (c) 1982, 1986, 1988, 1993
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6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
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14 * may be used to endorse or promote products derived from this software
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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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29 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
33 #include "opt_ipsec.h"
36 #include <sys/param.h>
37 #include <sys/systm.h>
39 #include <sys/protosw.h>
40 #include <sys/socket.h>
42 #include <sys/kernel.h>
43 #include <sys/sysctl.h>
46 #include <net/if_types.h>
47 #include <net/route.h>
49 #include <netinet/in.h>
50 #include <netinet/in_pcb.h>
51 #include <netinet/in_systm.h>
52 #include <netinet/in_var.h>
53 #include <netinet/ip.h>
54 #include <netinet/ip_icmp.h>
55 #include <netinet/ip_var.h>
56 #include <netinet/ip_options.h>
57 #include <netinet/tcp.h>
58 #include <netinet/tcp_var.h>
59 #include <netinet/tcpip.h>
60 #include <netinet/icmp_var.h>
63 #include <netinet6/ipsec.h>
64 #include <netkey/key.h>
68 #include <netipsec/ipsec.h>
69 #include <netipsec/key.h>
73 #include <machine/in_cksum.h>
75 #include <security/mac/mac_framework.h>
78 * ICMP routines: error generation, receive packet processing, and
79 * routines to turnaround packets back to the originator, and
80 * host table maintenance routines.
83 struct icmpstat icmpstat;
84 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW,
85 &icmpstat, icmpstat, "");
87 static int icmpmaskrepl = 0;
88 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
89 &icmpmaskrepl, 0, "Reply to ICMP Address Mask Request packets.");
91 static u_int icmpmaskfake = 0;
92 SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_RW,
93 &icmpmaskfake, 0, "Fake reply to ICMP Address Mask Request packets.");
95 static int drop_redirect = 0;
96 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW,
97 &drop_redirect, 0, "Ignore ICMP redirects");
99 static int log_redirect = 0;
100 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
101 &log_redirect, 0, "Log ICMP redirects to the console");
103 static int icmplim = 200;
104 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
105 &icmplim, 0, "Maximum number of ICMP responses per second");
107 static int icmplim_output = 1;
108 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
109 &icmplim_output, 0, "Enable rate limiting of ICMP responses");
111 static char reply_src[IFNAMSIZ];
112 SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW,
113 &reply_src, IFNAMSIZ, "icmp reply source for non-local packets.");
115 static int icmp_rfi = 0;
116 SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW,
117 &icmp_rfi, 0, "ICMP reply from incoming interface for "
118 "non-local packets");
120 static int icmp_quotelen = 8;
121 SYSCTL_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW,
122 &icmp_quotelen, 0, "Number of bytes from original packet to "
123 "quote in ICMP reply");
126 * ICMP broadcast echo sysctl
129 static int icmpbmcastecho = 0;
130 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
131 &icmpbmcastecho, 0, "");
138 static void icmp_reflect(struct mbuf *);
139 static void icmp_send(struct mbuf *, struct mbuf *);
141 extern struct protosw inetsw[];
144 * Generate an error packet of type error
145 * in response to bad packet ip.
148 icmp_error(n, type, code, dest, mtu)
154 register struct ip *oip = mtod(n, struct ip *), *nip;
155 register unsigned oiphlen = oip->ip_hl << 2;
156 register struct icmp *icp;
157 register struct mbuf *m;
158 unsigned icmplen, icmpelen, nlen;
160 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
163 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
165 if (type != ICMP_REDIRECT)
166 icmpstat.icps_error++;
169 * if the original packet was encrypted.
170 * if not the first fragment of message.
171 * in response to a multicast or broadcast packet.
172 * if the old packet protocol was an ICMP error message.
174 if (n->m_flags & M_DECRYPTED)
176 if (oip->ip_off & ~(IP_MF|IP_DF))
178 if (n->m_flags & (M_BCAST|M_MCAST))
180 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
181 n->m_len >= oiphlen + ICMP_MINLEN &&
182 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
183 icmpstat.icps_oldicmp++;
186 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
187 if (oiphlen + 8 > n->m_len)
190 * Calculate length to quote from original packet and
191 * prevent the ICMP mbuf from overflowing.
192 * Unfortunatly this is non-trivial since ip_forward()
193 * sends us truncated packets.
195 nlen = m_length(n, NULL);
196 if (oip->ip_p == IPPROTO_TCP) {
200 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
203 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
204 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
206 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
207 tcphlen = th->th_off << 2;
208 if (tcphlen < sizeof(struct tcphdr))
210 if (oip->ip_len < oiphlen + tcphlen)
212 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
214 if (n->m_len < oiphlen + tcphlen &&
215 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
217 icmpelen = max(tcphlen, min(icmp_quotelen, oip->ip_len - oiphlen));
219 stdreply: icmpelen = max(8, min(icmp_quotelen, oip->ip_len - oiphlen));
221 icmplen = min(oiphlen + icmpelen, nlen);
222 if (icmplen < sizeof(struct ip))
225 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
226 m = m_gethdr(M_DONTWAIT, MT_DATA);
228 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
232 mac_create_mbuf_netlayer(n, m);
234 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
235 m_align(m, ICMP_MINLEN + icmplen);
236 m->m_len = ICMP_MINLEN + icmplen;
238 icp = mtod(m, struct icmp *);
239 icmpstat.icps_outhist[type]++;
240 icp->icmp_type = type;
241 if (type == ICMP_REDIRECT)
242 icp->icmp_gwaddr.s_addr = dest;
246 * The following assignments assume an overlay with the
247 * just zeroed icmp_void field.
249 if (type == ICMP_PARAMPROB) {
250 icp->icmp_pptr = code;
252 } else if (type == ICMP_UNREACH &&
253 code == ICMP_UNREACH_NEEDFRAG && mtu) {
254 icp->icmp_nextmtu = htons(mtu);
257 icp->icmp_code = code;
260 * Copy the quotation into ICMP message and
261 * convert quoted IP header back to network representation.
263 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
265 nip->ip_len = htons(nip->ip_len);
266 nip->ip_off = htons(nip->ip_off);
269 * Set up ICMP message mbuf and copy old IP header (without options
270 * in front of ICMP message.
271 * If the original mbuf was meant to bypass the firewall, the error
272 * reply should bypass as well.
274 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
275 m->m_data -= sizeof(struct ip);
276 m->m_len += sizeof(struct ip);
277 m->m_pkthdr.len = m->m_len;
278 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
279 nip = mtod(m, struct ip *);
280 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
281 nip->ip_len = m->m_len;
282 nip->ip_v = IPVERSION;
284 nip->ip_p = IPPROTO_ICMP;
293 * Process a received ICMP message.
301 struct in_ifaddr *ia;
302 struct ip *ip = mtod(m, struct ip *);
303 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
305 int icmplen = ip->ip_len;
307 void (*ctlfunc)(int, struct sockaddr *, void *);
310 * Locate icmp structure in mbuf, and check
311 * that not corrupted and of at least minimum length.
315 char buf[4 * sizeof "123"];
316 strcpy(buf, inet_ntoa(ip->ip_src));
317 printf("icmp_input from %s to %s, len %d\n",
318 buf, inet_ntoa(ip->ip_dst), icmplen);
321 if (icmplen < ICMP_MINLEN) {
322 icmpstat.icps_tooshort++;
325 i = hlen + min(icmplen, ICMP_ADVLENMIN);
326 if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
327 icmpstat.icps_tooshort++;
330 ip = mtod(m, struct ip *);
333 icp = mtod(m, struct icmp *);
334 if (in_cksum(m, icmplen)) {
335 icmpstat.icps_checksum++;
341 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
343 * Deliver very specific ICMP type only.
345 switch (icp->icmp_type) {
356 printf("icmp_input, type %d code %d\n", icp->icmp_type,
361 * Message type specific processing.
363 if (icp->icmp_type > ICMP_MAXTYPE)
367 bzero(&icmpsrc, sizeof(icmpsrc));
368 icmpsrc.sin_len = sizeof(struct sockaddr_in);
369 icmpsrc.sin_family = AF_INET;
370 bzero(&icmpdst, sizeof(icmpdst));
371 icmpdst.sin_len = sizeof(struct sockaddr_in);
372 icmpdst.sin_family = AF_INET;
373 bzero(&icmpgw, sizeof(icmpgw));
374 icmpgw.sin_len = sizeof(struct sockaddr_in);
375 icmpgw.sin_family = AF_INET;
377 icmpstat.icps_inhist[icp->icmp_type]++;
378 code = icp->icmp_code;
379 switch (icp->icmp_type) {
383 case ICMP_UNREACH_NET:
384 case ICMP_UNREACH_HOST:
385 case ICMP_UNREACH_SRCFAIL:
386 case ICMP_UNREACH_NET_UNKNOWN:
387 case ICMP_UNREACH_HOST_UNKNOWN:
388 case ICMP_UNREACH_ISOLATED:
389 case ICMP_UNREACH_TOSNET:
390 case ICMP_UNREACH_TOSHOST:
391 case ICMP_UNREACH_HOST_PRECEDENCE:
392 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
393 code = PRC_UNREACH_NET;
396 case ICMP_UNREACH_NEEDFRAG:
401 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
402 * Treat subcodes 2,3 as immediate RST
404 case ICMP_UNREACH_PROTOCOL:
405 case ICMP_UNREACH_PORT:
406 code = PRC_UNREACH_PORT;
409 case ICMP_UNREACH_NET_PROHIB:
410 case ICMP_UNREACH_HOST_PROHIB:
411 case ICMP_UNREACH_FILTER_PROHIB:
412 code = PRC_UNREACH_ADMIN_PROHIB;
423 code += PRC_TIMXCEED_INTRANS;
429 code = PRC_PARAMPROB;
432 case ICMP_SOURCEQUENCH:
438 * Problem with datagram; advise higher level routines.
440 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
441 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
442 icmpstat.icps_badlen++;
445 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
446 /* Discard ICMP's in response to multicast packets */
447 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
451 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
453 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
455 * XXX if the packet contains [IPv4 AH TCP], we can't make a
456 * notification to TCP layer.
458 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
460 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
461 (void *)&icp->icmp_ip);
465 icmpstat.icps_badcode++;
470 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
471 icmpstat.icps_bmcastecho++;
474 icp->icmp_type = ICMP_ECHOREPLY;
475 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
482 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
483 icmpstat.icps_bmcasttstamp++;
486 if (icmplen < ICMP_TSLEN) {
487 icmpstat.icps_badlen++;
490 icp->icmp_type = ICMP_TSTAMPREPLY;
491 icp->icmp_rtime = iptime();
492 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
493 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
499 if (icmpmaskrepl == 0)
502 * We are not able to respond with all ones broadcast
503 * unless we receive it over a point-to-point interface.
505 if (icmplen < ICMP_MASKLEN)
507 switch (ip->ip_dst.s_addr) {
509 case INADDR_BROADCAST:
511 icmpdst.sin_addr = ip->ip_src;
515 icmpdst.sin_addr = ip->ip_dst;
517 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
518 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
523 icp->icmp_type = ICMP_MASKREPLY;
524 if (icmpmaskfake == 0)
525 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
527 icp->icmp_mask = icmpmaskfake;
528 if (ip->ip_src.s_addr == 0) {
529 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
530 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
531 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
532 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
535 ip->ip_len += hlen; /* since ip_input deducts this */
536 icmpstat.icps_reflect++;
537 icmpstat.icps_outhist[icp->icmp_type]++;
545 src = ntohl(ip->ip_src.s_addr);
546 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
547 gw = ntohl(icp->icmp_gwaddr.s_addr);
548 printf("icmp redirect from %d.%d.%d.%d: "
549 "%d.%d.%d.%d => %d.%d.%d.%d\n",
550 (int)(src >> 24), (int)((src >> 16) & 0xff),
551 (int)((src >> 8) & 0xff), (int)(src & 0xff),
552 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
553 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
554 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
555 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
558 * RFC1812 says we must ignore ICMP redirects if we
559 * are acting as router.
561 if (drop_redirect || ipforwarding)
565 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
566 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
567 icmpstat.icps_badlen++;
571 * Short circuit routing redirects to force
572 * immediate change in the kernel's routing
573 * tables. The message is also handed to anyone
574 * listening on a raw socket (e.g. the routing
575 * daemon for use in updating its tables).
577 icmpgw.sin_addr = ip->ip_src;
578 icmpdst.sin_addr = icp->icmp_gwaddr;
581 char buf[4 * sizeof "123"];
582 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
584 printf("redirect dst %s to %s\n",
585 buf, inet_ntoa(icp->icmp_gwaddr));
588 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
589 rtredirect((struct sockaddr *)&icmpsrc,
590 (struct sockaddr *)&icmpdst,
591 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
592 (struct sockaddr *)&icmpgw);
593 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
595 key_sa_routechange((struct sockaddr *)&icmpsrc);
600 * No kernel processing for the following;
601 * just fall through to send to raw listener.
604 case ICMP_ROUTERADVERT:
605 case ICMP_ROUTERSOLICIT:
606 case ICMP_TSTAMPREPLY:
622 * Reflect the ip packet back to the source
628 struct ip *ip = mtod(m, struct ip *);
631 struct in_ifaddr *ia;
633 struct mbuf *opts = 0;
634 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
636 if (!in_canforward(ip->ip_src) &&
637 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) !=
638 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
639 m_freem(m); /* Bad return address */
640 icmpstat.icps_badaddr++;
641 goto done; /* Ip_output() will check for broadcast */
644 ip->ip_dst = ip->ip_src;
647 * Source selection for ICMP replies:
649 * If the incoming packet was addressed directly to one of our
650 * own addresses, use dst as the src for the reply.
652 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash)
653 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
656 * If the incoming packet was addressed to one of our broadcast
657 * addresses, use the first non-broadcast address which corresponds
658 * to the incoming interface.
660 if (m->m_pkthdr.rcvif != NULL &&
661 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
662 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
663 if (ifa->ifa_addr->sa_family != AF_INET)
666 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
672 * If the packet was transiting through us, use the address of
673 * the interface the packet came through in. If that interface
674 * doesn't have a suitable IP address, the normal selection
677 if (icmp_rfi && m->m_pkthdr.rcvif != NULL) {
678 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
679 if (ifa->ifa_addr->sa_family != AF_INET)
686 * If the incoming packet was not addressed directly to us, use
687 * designated interface for icmp replies specified by sysctl
688 * net.inet.icmp.reply_src (default not set). Otherwise continue
689 * with normal source selection.
691 if (reply_src[0] != '\0' && (ifn = ifunit(reply_src))) {
692 TAILQ_FOREACH(ifa, &ifn->if_addrhead, ifa_link) {
693 if (ifa->ifa_addr->sa_family != AF_INET)
700 * If the packet was transiting through us, use the address of
701 * the interface that is the closest to the packet source.
702 * When we don't have a route back to the packet source, stop here
703 * and drop the packet.
705 ia = ip_rtaddr(ip->ip_dst);
708 icmpstat.icps_noroute++;
713 mac_reflect_mbuf_icmp(m);
715 t = IA_SIN(ia)->sin_addr;
717 ip->ip_ttl = ip_defttl;
725 * Retrieve any source routing from the incoming packet;
726 * add on any record-route or timestamp options.
728 cp = (u_char *) (ip + 1);
729 if ((opts = ip_srcroute(m)) == 0 &&
730 (opts = m_gethdr(M_DONTWAIT, MT_DATA))) {
731 opts->m_len = sizeof(struct in_addr);
732 mtod(opts, struct in_addr *)->s_addr = 0;
737 printf("icmp_reflect optlen %d rt %d => ",
738 optlen, opts->m_len);
740 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
741 opt = cp[IPOPT_OPTVAL];
742 if (opt == IPOPT_EOL)
744 if (opt == IPOPT_NOP)
747 if (cnt < IPOPT_OLEN + sizeof(*cp))
749 len = cp[IPOPT_OLEN];
750 if (len < IPOPT_OLEN + sizeof(*cp) ||
755 * Should check for overflow, but it "can't happen"
757 if (opt == IPOPT_RR || opt == IPOPT_TS ||
758 opt == IPOPT_SECURITY) {
760 mtod(opts, caddr_t) + opts->m_len, len);
764 /* Terminate & pad, if necessary */
765 cnt = opts->m_len % 4;
767 for (; cnt < 4; cnt++) {
768 *(mtod(opts, caddr_t) + opts->m_len) =
775 printf("%d\n", opts->m_len);
779 * Now strip out original options by copying rest of first
780 * mbuf's data back, and adjust the IP length.
782 ip->ip_len -= optlen;
783 ip->ip_v = IPVERSION;
786 if (m->m_flags & M_PKTHDR)
787 m->m_pkthdr.len -= optlen;
788 optlen += sizeof(struct ip);
789 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
790 (unsigned)(m->m_len - sizeof(struct ip)));
792 m_tag_delete_nonpersistent(m);
793 m->m_flags &= ~(M_BCAST|M_MCAST);
801 * Send an icmp packet back to the ip level,
802 * after supplying a checksum.
806 register struct mbuf *m;
809 register struct ip *ip = mtod(m, struct ip *);
811 register struct icmp *icp;
813 hlen = ip->ip_hl << 2;
816 icp = mtod(m, struct icmp *);
818 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
821 m->m_pkthdr.rcvif = (struct ifnet *)0;
824 char buf[4 * sizeof "123"];
825 strcpy(buf, inet_ntoa(ip->ip_dst));
826 printf("icmp_send dst %s src %s\n",
827 buf, inet_ntoa(ip->ip_src));
830 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
840 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
845 * Return the next larger or smaller MTU plateau (table from RFC 1191)
846 * given current value MTU. If DIR is less than zero, a larger plateau
847 * is returned; otherwise, a smaller value is returned.
850 ip_next_mtu(mtu, dir)
854 static int mtutab[] = {
855 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
860 size = (sizeof mtutab) / (sizeof mtutab[0]);
862 for (i = 0; i < size; i++)
866 for (i = size - 1; i >= 0; i--)
869 if (mtu == mtutab[0])
877 * badport_bandlim() - check for ICMP bandwidth limit
879 * Return 0 if it is ok to send an ICMP error response, -1 if we have
880 * hit our bandwidth limit and it is not ok.
882 * If icmplim is <= 0, the feature is disabled and 0 is returned.
884 * For now we separate the TCP and UDP subsystems w/ different 'which'
885 * values. We may eventually remove this separation (and simplify the
888 * Note that the printing of the error message is delayed so we can
889 * properly print the icmp error rate that the system was trying to do
890 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
891 * the 'final' error, but it doesn't make sense to solve the printing
892 * delay with more complex code.
896 badport_bandlim(int which)
898 #define N(a) (sizeof (a) / sizeof (a[0]))
901 struct timeval lasttime;
903 } rates[BANDLIM_MAX+1] = {
904 { "icmp unreach response" },
905 { "icmp ping response" },
906 { "icmp tstamp response" },
907 { "closed port RST response" },
908 { "open port RST response" }
912 * Return ok status if feature disabled or argument out of range.
914 if (icmplim > 0 && (u_int) which < N(rates)) {
915 struct rate *r = &rates[which];
916 int opps = r->curpps;
918 if (!ppsratecheck(&r->lasttime, &r->curpps, icmplim))
919 return -1; /* discard packet */
921 * If we've dropped below the threshold after having
922 * rate-limited traffic print the message. This preserves
923 * the previous behaviour at the expense of added complexity.
925 if (icmplim_output && opps > icmplim)
926 printf("Limiting %s from %d to %d packets/sec\n",
927 r->type, opps, icmplim);
929 return 0; /* okay to send packet */