2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
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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.
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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 <netipsec/ipsec.h>
64 #include <netipsec/key.h>
67 #include <machine/in_cksum.h>
69 #include <security/mac/mac_framework.h>
72 * ICMP routines: error generation, receive packet processing, and
73 * routines to turnaround packets back to the originator, and
74 * host table maintenance routines.
77 struct icmpstat icmpstat;
78 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW,
79 &icmpstat, icmpstat, "");
81 static int icmpmaskrepl = 0;
82 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
83 &icmpmaskrepl, 0, "Reply to ICMP Address Mask Request packets.");
85 static u_int icmpmaskfake = 0;
86 SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_RW,
87 &icmpmaskfake, 0, "Fake reply to ICMP Address Mask Request packets.");
89 static int drop_redirect = 0;
90 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW,
91 &drop_redirect, 0, "Ignore ICMP redirects");
93 static int log_redirect = 0;
94 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
95 &log_redirect, 0, "Log ICMP redirects to the console");
97 static int icmplim = 200;
98 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
99 &icmplim, 0, "Maximum number of ICMP responses per second");
101 static int icmplim_output = 1;
102 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
103 &icmplim_output, 0, "Enable rate limiting of ICMP responses");
105 static char reply_src[IFNAMSIZ];
106 SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW,
107 &reply_src, IFNAMSIZ, "icmp reply source for non-local packets.");
109 static int icmp_rfi = 0;
110 SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW,
111 &icmp_rfi, 0, "ICMP reply from incoming interface for "
112 "non-local packets");
114 static int icmp_quotelen = 8;
115 SYSCTL_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW,
116 &icmp_quotelen, 0, "Number of bytes from original packet to "
117 "quote in ICMP reply");
120 * ICMP broadcast echo sysctl
123 static int icmpbmcastecho = 0;
124 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
125 &icmpbmcastecho, 0, "");
132 static void icmp_reflect(struct mbuf *);
133 static void icmp_send(struct mbuf *, struct mbuf *);
135 extern struct protosw inetsw[];
138 * Generate an error packet of type error
139 * in response to bad packet ip.
142 icmp_error(struct mbuf *n, int type, int code, n_long dest, int mtu)
144 register struct ip *oip = mtod(n, struct ip *), *nip;
145 register unsigned oiphlen = oip->ip_hl << 2;
146 register struct icmp *icp;
147 register struct mbuf *m;
148 unsigned icmplen, icmpelen, nlen;
150 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
153 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
155 if (type != ICMP_REDIRECT)
156 icmpstat.icps_error++;
159 * if the original packet was encrypted.
160 * if not the first fragment of message.
161 * in response to a multicast or broadcast packet.
162 * if the old packet protocol was an ICMP error message.
164 if (n->m_flags & M_DECRYPTED)
166 if (oip->ip_off & ~(IP_MF|IP_DF))
168 if (n->m_flags & (M_BCAST|M_MCAST))
170 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
171 n->m_len >= oiphlen + ICMP_MINLEN &&
172 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
173 icmpstat.icps_oldicmp++;
176 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
177 if (oiphlen + 8 > n->m_len)
180 * Calculate length to quote from original packet and
181 * prevent the ICMP mbuf from overflowing.
182 * Unfortunatly this is non-trivial since ip_forward()
183 * sends us truncated packets.
185 nlen = m_length(n, NULL);
186 if (oip->ip_p == IPPROTO_TCP) {
190 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
193 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
194 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
196 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
197 tcphlen = th->th_off << 2;
198 if (tcphlen < sizeof(struct tcphdr))
200 if (oip->ip_len < oiphlen + tcphlen)
202 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
204 if (n->m_len < oiphlen + tcphlen &&
205 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
207 icmpelen = max(tcphlen, min(icmp_quotelen, oip->ip_len - oiphlen));
209 stdreply: icmpelen = max(8, min(icmp_quotelen, oip->ip_len - oiphlen));
211 icmplen = min(oiphlen + icmpelen, nlen);
212 if (icmplen < sizeof(struct ip))
215 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
216 m = m_gethdr(M_DONTWAIT, MT_DATA);
218 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
222 mac_create_mbuf_netlayer(n, m);
224 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
225 m_align(m, ICMP_MINLEN + icmplen);
226 m->m_len = ICMP_MINLEN + icmplen;
228 icp = mtod(m, struct icmp *);
229 icmpstat.icps_outhist[type]++;
230 icp->icmp_type = type;
231 if (type == ICMP_REDIRECT)
232 icp->icmp_gwaddr.s_addr = dest;
236 * The following assignments assume an overlay with the
237 * just zeroed icmp_void field.
239 if (type == ICMP_PARAMPROB) {
240 icp->icmp_pptr = code;
242 } else if (type == ICMP_UNREACH &&
243 code == ICMP_UNREACH_NEEDFRAG && mtu) {
244 icp->icmp_nextmtu = htons(mtu);
247 icp->icmp_code = code;
250 * Copy the quotation into ICMP message and
251 * convert quoted IP header back to network representation.
253 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
255 nip->ip_len = htons(nip->ip_len);
256 nip->ip_off = htons(nip->ip_off);
259 * Set up ICMP message mbuf and copy old IP header (without options
260 * in front of ICMP message.
261 * If the original mbuf was meant to bypass the firewall, the error
262 * reply should bypass as well.
264 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
265 m->m_data -= sizeof(struct ip);
266 m->m_len += sizeof(struct ip);
267 m->m_pkthdr.len = m->m_len;
268 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
269 nip = mtod(m, struct ip *);
270 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
271 nip->ip_len = m->m_len;
272 nip->ip_v = IPVERSION;
274 nip->ip_p = IPPROTO_ICMP;
283 * Process a received ICMP message.
286 icmp_input(struct mbuf *m, int off)
289 struct in_ifaddr *ia;
290 struct ip *ip = mtod(m, struct ip *);
291 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
293 int icmplen = ip->ip_len;
295 void (*ctlfunc)(int, struct sockaddr *, void *);
298 * Locate icmp structure in mbuf, and check
299 * that not corrupted and of at least minimum length.
303 char buf[4 * sizeof "123"];
304 strcpy(buf, inet_ntoa(ip->ip_src));
305 printf("icmp_input from %s to %s, len %d\n",
306 buf, inet_ntoa(ip->ip_dst), icmplen);
309 if (icmplen < ICMP_MINLEN) {
310 icmpstat.icps_tooshort++;
313 i = hlen + min(icmplen, ICMP_ADVLENMIN);
314 if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
315 icmpstat.icps_tooshort++;
318 ip = mtod(m, struct ip *);
321 icp = mtod(m, struct icmp *);
322 if (in_cksum(m, icmplen)) {
323 icmpstat.icps_checksum++;
329 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
331 * Deliver very specific ICMP type only.
333 switch (icp->icmp_type) {
344 printf("icmp_input, type %d code %d\n", icp->icmp_type,
349 * Message type specific processing.
351 if (icp->icmp_type > ICMP_MAXTYPE)
355 bzero(&icmpsrc, sizeof(icmpsrc));
356 icmpsrc.sin_len = sizeof(struct sockaddr_in);
357 icmpsrc.sin_family = AF_INET;
358 bzero(&icmpdst, sizeof(icmpdst));
359 icmpdst.sin_len = sizeof(struct sockaddr_in);
360 icmpdst.sin_family = AF_INET;
361 bzero(&icmpgw, sizeof(icmpgw));
362 icmpgw.sin_len = sizeof(struct sockaddr_in);
363 icmpgw.sin_family = AF_INET;
365 icmpstat.icps_inhist[icp->icmp_type]++;
366 code = icp->icmp_code;
367 switch (icp->icmp_type) {
371 case ICMP_UNREACH_NET:
372 case ICMP_UNREACH_HOST:
373 case ICMP_UNREACH_SRCFAIL:
374 case ICMP_UNREACH_NET_UNKNOWN:
375 case ICMP_UNREACH_HOST_UNKNOWN:
376 case ICMP_UNREACH_ISOLATED:
377 case ICMP_UNREACH_TOSNET:
378 case ICMP_UNREACH_TOSHOST:
379 case ICMP_UNREACH_HOST_PRECEDENCE:
380 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
381 code = PRC_UNREACH_NET;
384 case ICMP_UNREACH_NEEDFRAG:
389 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
390 * Treat subcodes 2,3 as immediate RST
392 case ICMP_UNREACH_PROTOCOL:
393 case ICMP_UNREACH_PORT:
394 code = PRC_UNREACH_PORT;
397 case ICMP_UNREACH_NET_PROHIB:
398 case ICMP_UNREACH_HOST_PROHIB:
399 case ICMP_UNREACH_FILTER_PROHIB:
400 code = PRC_UNREACH_ADMIN_PROHIB;
411 code += PRC_TIMXCEED_INTRANS;
417 code = PRC_PARAMPROB;
420 case ICMP_SOURCEQUENCH:
426 * Problem with datagram; advise higher level routines.
428 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
429 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
430 icmpstat.icps_badlen++;
433 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
434 /* Discard ICMP's in response to multicast packets */
435 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
439 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
441 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
443 * XXX if the packet contains [IPv4 AH TCP], we can't make a
444 * notification to TCP layer.
446 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
448 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
449 (void *)&icp->icmp_ip);
453 icmpstat.icps_badcode++;
458 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
459 icmpstat.icps_bmcastecho++;
462 icp->icmp_type = ICMP_ECHOREPLY;
463 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
470 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
471 icmpstat.icps_bmcasttstamp++;
474 if (icmplen < ICMP_TSLEN) {
475 icmpstat.icps_badlen++;
478 icp->icmp_type = ICMP_TSTAMPREPLY;
479 icp->icmp_rtime = iptime();
480 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
481 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
487 if (icmpmaskrepl == 0)
490 * We are not able to respond with all ones broadcast
491 * unless we receive it over a point-to-point interface.
493 if (icmplen < ICMP_MASKLEN)
495 switch (ip->ip_dst.s_addr) {
497 case INADDR_BROADCAST:
499 icmpdst.sin_addr = ip->ip_src;
503 icmpdst.sin_addr = ip->ip_dst;
505 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
506 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
511 icp->icmp_type = ICMP_MASKREPLY;
512 if (icmpmaskfake == 0)
513 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
515 icp->icmp_mask = icmpmaskfake;
516 if (ip->ip_src.s_addr == 0) {
517 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
518 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
519 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
520 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
523 ip->ip_len += hlen; /* since ip_input deducts this */
524 icmpstat.icps_reflect++;
525 icmpstat.icps_outhist[icp->icmp_type]++;
533 src = ntohl(ip->ip_src.s_addr);
534 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
535 gw = ntohl(icp->icmp_gwaddr.s_addr);
536 printf("icmp redirect from %d.%d.%d.%d: "
537 "%d.%d.%d.%d => %d.%d.%d.%d\n",
538 (int)(src >> 24), (int)((src >> 16) & 0xff),
539 (int)((src >> 8) & 0xff), (int)(src & 0xff),
540 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
541 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
542 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
543 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
546 * RFC1812 says we must ignore ICMP redirects if we
547 * are acting as router.
549 if (drop_redirect || ipforwarding)
553 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
554 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
555 icmpstat.icps_badlen++;
559 * Short circuit routing redirects to force
560 * immediate change in the kernel's routing
561 * tables. The message is also handed to anyone
562 * listening on a raw socket (e.g. the routing
563 * daemon for use in updating its tables).
565 icmpgw.sin_addr = ip->ip_src;
566 icmpdst.sin_addr = icp->icmp_gwaddr;
569 char buf[4 * sizeof "123"];
570 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
572 printf("redirect dst %s to %s\n",
573 buf, inet_ntoa(icp->icmp_gwaddr));
576 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
577 rtredirect((struct sockaddr *)&icmpsrc,
578 (struct sockaddr *)&icmpdst,
579 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
580 (struct sockaddr *)&icmpgw);
581 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
583 key_sa_routechange((struct sockaddr *)&icmpsrc);
588 * No kernel processing for the following;
589 * just fall through to send to raw listener.
592 case ICMP_ROUTERADVERT:
593 case ICMP_ROUTERSOLICIT:
594 case ICMP_TSTAMPREPLY:
610 * Reflect the ip packet back to the source
613 icmp_reflect(struct mbuf *m)
615 struct ip *ip = mtod(m, struct ip *);
618 struct in_ifaddr *ia;
620 struct mbuf *opts = 0;
621 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
623 if (!in_canforward(ip->ip_src) &&
624 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) !=
625 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
626 m_freem(m); /* Bad return address */
627 icmpstat.icps_badaddr++;
628 goto done; /* Ip_output() will check for broadcast */
631 ip->ip_dst = ip->ip_src;
634 * Source selection for ICMP replies:
636 * If the incoming packet was addressed directly to one of our
637 * own addresses, use dst as the src for the reply.
639 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash)
640 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
643 * If the incoming packet was addressed to one of our broadcast
644 * addresses, use the first non-broadcast address which corresponds
645 * to the incoming interface.
647 if (m->m_pkthdr.rcvif != NULL &&
648 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
649 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
650 if (ifa->ifa_addr->sa_family != AF_INET)
653 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
659 * If the packet was transiting through us, use the address of
660 * the interface the packet came through in. If that interface
661 * doesn't have a suitable IP address, the normal selection
664 if (icmp_rfi && m->m_pkthdr.rcvif != NULL) {
665 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
666 if (ifa->ifa_addr->sa_family != AF_INET)
673 * If the incoming packet was not addressed directly to us, use
674 * designated interface for icmp replies specified by sysctl
675 * net.inet.icmp.reply_src (default not set). Otherwise continue
676 * with normal source selection.
678 if (reply_src[0] != '\0' && (ifn = ifunit(reply_src))) {
679 TAILQ_FOREACH(ifa, &ifn->if_addrhead, ifa_link) {
680 if (ifa->ifa_addr->sa_family != AF_INET)
687 * If the packet was transiting through us, use the address of
688 * the interface that is the closest to the packet source.
689 * When we don't have a route back to the packet source, stop here
690 * and drop the packet.
692 ia = ip_rtaddr(ip->ip_dst);
695 icmpstat.icps_noroute++;
700 mac_reflect_mbuf_icmp(m);
702 t = IA_SIN(ia)->sin_addr;
704 ip->ip_ttl = ip_defttl;
712 * Retrieve any source routing from the incoming packet;
713 * add on any record-route or timestamp options.
715 cp = (u_char *) (ip + 1);
716 if ((opts = ip_srcroute(m)) == 0 &&
717 (opts = m_gethdr(M_DONTWAIT, MT_DATA))) {
718 opts->m_len = sizeof(struct in_addr);
719 mtod(opts, struct in_addr *)->s_addr = 0;
724 printf("icmp_reflect optlen %d rt %d => ",
725 optlen, opts->m_len);
727 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
728 opt = cp[IPOPT_OPTVAL];
729 if (opt == IPOPT_EOL)
731 if (opt == IPOPT_NOP)
734 if (cnt < IPOPT_OLEN + sizeof(*cp))
736 len = cp[IPOPT_OLEN];
737 if (len < IPOPT_OLEN + sizeof(*cp) ||
742 * Should check for overflow, but it "can't happen"
744 if (opt == IPOPT_RR || opt == IPOPT_TS ||
745 opt == IPOPT_SECURITY) {
747 mtod(opts, caddr_t) + opts->m_len, len);
751 /* Terminate & pad, if necessary */
752 cnt = opts->m_len % 4;
754 for (; cnt < 4; cnt++) {
755 *(mtod(opts, caddr_t) + opts->m_len) =
762 printf("%d\n", opts->m_len);
766 * Now strip out original options by copying rest of first
767 * mbuf's data back, and adjust the IP length.
769 ip->ip_len -= optlen;
770 ip->ip_v = IPVERSION;
773 if (m->m_flags & M_PKTHDR)
774 m->m_pkthdr.len -= optlen;
775 optlen += sizeof(struct ip);
776 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
777 (unsigned)(m->m_len - sizeof(struct ip)));
779 m_tag_delete_nonpersistent(m);
780 m->m_flags &= ~(M_BCAST|M_MCAST);
788 * Send an icmp packet back to the ip level,
789 * after supplying a checksum.
792 icmp_send(struct mbuf *m, struct mbuf *opts)
794 register struct ip *ip = mtod(m, struct ip *);
796 register struct icmp *icp;
798 hlen = ip->ip_hl << 2;
801 icp = mtod(m, struct icmp *);
803 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
806 m->m_pkthdr.rcvif = (struct ifnet *)0;
809 char buf[4 * sizeof "123"];
810 strcpy(buf, inet_ntoa(ip->ip_dst));
811 printf("icmp_send dst %s src %s\n",
812 buf, inet_ntoa(ip->ip_src));
815 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
825 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
830 * Return the next larger or smaller MTU plateau (table from RFC 1191)
831 * given current value MTU. If DIR is less than zero, a larger plateau
832 * is returned; otherwise, a smaller value is returned.
835 ip_next_mtu(int mtu, int dir)
837 static int mtutab[] = {
838 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
843 size = (sizeof mtutab) / (sizeof mtutab[0]);
845 for (i = 0; i < size; i++)
849 for (i = size - 1; i >= 0; i--)
852 if (mtu == mtutab[0])
860 * badport_bandlim() - check for ICMP bandwidth limit
862 * Return 0 if it is ok to send an ICMP error response, -1 if we have
863 * hit our bandwidth limit and it is not ok.
865 * If icmplim is <= 0, the feature is disabled and 0 is returned.
867 * For now we separate the TCP and UDP subsystems w/ different 'which'
868 * values. We may eventually remove this separation (and simplify the
871 * Note that the printing of the error message is delayed so we can
872 * properly print the icmp error rate that the system was trying to do
873 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
874 * the 'final' error, but it doesn't make sense to solve the printing
875 * delay with more complex code.
879 badport_bandlim(int which)
881 #define N(a) (sizeof (a) / sizeof (a[0]))
884 struct timeval lasttime;
886 } rates[BANDLIM_MAX+1] = {
887 { "icmp unreach response" },
888 { "icmp ping response" },
889 { "icmp tstamp response" },
890 { "closed port RST response" },
891 { "open port RST response" },
892 { "icmp6 unreach response" }
896 * Return ok status if feature disabled or argument out of range.
898 if (icmplim > 0 && (u_int) which < N(rates)) {
899 struct rate *r = &rates[which];
900 int opps = r->curpps;
902 if (!ppsratecheck(&r->lasttime, &r->curpps, icmplim))
903 return -1; /* discard packet */
905 * If we've dropped below the threshold after having
906 * rate-limited traffic print the message. This preserves
907 * the previous behaviour at the expense of added complexity.
909 if (icmplim_output && opps > icmplim)
910 printf("Limiting %s from %d to %d packets/sec\n",
911 r->type, opps, icmplim);
913 return 0; /* okay to send packet */