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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
36 #include "opt_ipsec.h"
38 #include <sys/param.h>
39 #include <sys/systm.h>
41 #include <sys/protosw.h>
42 #include <sys/socket.h>
44 #include <sys/kernel.h>
45 #include <sys/sysctl.h>
46 #include <sys/syslog.h>
49 #include <net/if_types.h>
50 #include <net/route.h>
53 #include <netinet/in.h>
54 #include <netinet/in_pcb.h>
55 #include <netinet/in_systm.h>
56 #include <netinet/in_var.h>
57 #include <netinet/ip.h>
58 #include <netinet/ip_icmp.h>
59 #include <netinet/ip_var.h>
60 #include <netinet/ip_options.h>
61 #include <netinet/tcp.h>
62 #include <netinet/tcp_var.h>
63 #include <netinet/tcpip.h>
64 #include <netinet/icmp_var.h>
68 #include <netipsec/ipsec.h>
69 #include <netipsec/key.h>
72 #include <machine/in_cksum.h>
74 #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.
82 static VNET_DEFINE(int, icmplim) = 200;
83 #define V_icmplim VNET(icmplim)
84 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
85 &VNET_NAME(icmplim), 0,
86 "Maximum number of ICMP responses per second");
88 static VNET_DEFINE(int, icmplim_output) = 1;
89 #define V_icmplim_output VNET(icmplim_output)
90 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
91 &VNET_NAME(icmplim_output), 0,
92 "Enable rate limiting of ICMP responses");
95 VNET_DEFINE(struct icmpstat, icmpstat);
96 SYSCTL_VNET_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW,
97 &VNET_NAME(icmpstat), icmpstat, "");
99 static VNET_DEFINE(int, icmpmaskrepl) = 0;
100 #define V_icmpmaskrepl VNET(icmpmaskrepl)
101 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
102 &VNET_NAME(icmpmaskrepl), 0,
103 "Reply to ICMP Address Mask Request packets.");
105 static VNET_DEFINE(u_int, icmpmaskfake) = 0;
106 #define V_icmpmaskfake VNET(icmpmaskfake)
107 SYSCTL_VNET_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_RW,
108 &VNET_NAME(icmpmaskfake), 0,
109 "Fake reply to ICMP Address Mask Request packets.");
111 static VNET_DEFINE(int, drop_redirect) = 0;
112 #define V_drop_redirect VNET(drop_redirect)
113 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW,
114 &VNET_NAME(drop_redirect), 0,
115 "Ignore ICMP redirects");
117 static VNET_DEFINE(int, log_redirect) = 0;
118 #define V_log_redirect VNET(log_redirect)
119 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
120 &VNET_NAME(log_redirect), 0,
121 "Log ICMP redirects to the console");
123 static VNET_DEFINE(char, reply_src[IFNAMSIZ]);
124 #define V_reply_src VNET(reply_src)
125 SYSCTL_VNET_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW,
126 &VNET_NAME(reply_src), IFNAMSIZ,
127 "icmp reply source for non-local packets.");
129 static VNET_DEFINE(int, icmp_rfi) = 0;
130 #define V_icmp_rfi VNET(icmp_rfi)
131 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW,
132 &VNET_NAME(icmp_rfi), 0,
133 "ICMP reply from incoming interface for non-local packets");
135 static VNET_DEFINE(int, icmp_quotelen) = 8;
136 #define V_icmp_quotelen VNET(icmp_quotelen)
137 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW,
138 &VNET_NAME(icmp_quotelen), 0,
139 "Number of bytes from original packet to quote in ICMP reply");
142 * ICMP broadcast echo sysctl
144 static VNET_DEFINE(int, icmpbmcastecho) = 0;
145 #define V_icmpbmcastecho VNET(icmpbmcastecho)
146 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
147 &VNET_NAME(icmpbmcastecho), 0,
155 static void icmp_reflect(struct mbuf *);
156 static void icmp_send(struct mbuf *, struct mbuf *);
158 extern struct protosw inetsw[];
161 * Kernel module interface for updating icmpstat. The argument is an index
162 * into icmpstat treated as an array of u_long. While this encodes the
163 * general layout of icmpstat into the caller, it doesn't encode its
164 * location, so that future changes to add, for example, per-CPU stats
165 * support won't cause binary compatibility problems for kernel modules.
168 kmod_icmpstat_inc(int statnum)
171 (*((u_long *)&V_icmpstat + statnum))++;
175 * Generate an error packet of type error
176 * in response to bad packet ip.
179 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
181 register struct ip *oip = mtod(n, struct ip *), *nip;
182 register unsigned oiphlen = oip->ip_hl << 2;
183 register struct icmp *icp;
184 register struct mbuf *m;
185 unsigned icmplen, icmpelen, nlen;
187 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
190 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
192 if (type != ICMP_REDIRECT)
193 ICMPSTAT_INC(icps_error);
196 * if the original packet was encrypted.
197 * if not the first fragment of message.
198 * in response to a multicast or broadcast packet.
199 * if the old packet protocol was an ICMP error message.
201 if (n->m_flags & M_DECRYPTED)
203 if (oip->ip_off & ~(IP_MF|IP_DF))
205 if (n->m_flags & (M_BCAST|M_MCAST))
207 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
208 n->m_len >= oiphlen + ICMP_MINLEN &&
209 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
210 ICMPSTAT_INC(icps_oldicmp);
213 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
214 if (oiphlen + 8 > n->m_len)
217 * Calculate length to quote from original packet and
218 * prevent the ICMP mbuf from overflowing.
219 * Unfortunatly this is non-trivial since ip_forward()
220 * sends us truncated packets.
222 nlen = m_length(n, NULL);
223 if (oip->ip_p == IPPROTO_TCP) {
227 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
230 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
231 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
233 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
234 tcphlen = th->th_off << 2;
235 if (tcphlen < sizeof(struct tcphdr))
237 if (oip->ip_len < oiphlen + tcphlen)
239 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
241 if (n->m_len < oiphlen + tcphlen &&
242 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
244 icmpelen = max(tcphlen, min(V_icmp_quotelen, oip->ip_len - oiphlen));
246 stdreply: icmpelen = max(8, min(V_icmp_quotelen, oip->ip_len - oiphlen));
248 icmplen = min(oiphlen + icmpelen, nlen);
249 if (icmplen < sizeof(struct ip))
252 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
253 m = m_gethdr(M_DONTWAIT, MT_DATA);
255 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
259 mac_netinet_icmp_reply(n, m);
261 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
262 m_align(m, ICMP_MINLEN + icmplen);
263 m->m_len = ICMP_MINLEN + icmplen;
265 /* XXX MRT make the outgoing packet use the same FIB
266 * that was associated with the incoming packet
268 M_SETFIB(m, M_GETFIB(n));
269 icp = mtod(m, struct icmp *);
270 ICMPSTAT_INC(icps_outhist[type]);
271 icp->icmp_type = type;
272 if (type == ICMP_REDIRECT)
273 icp->icmp_gwaddr.s_addr = dest;
277 * The following assignments assume an overlay with the
278 * just zeroed icmp_void field.
280 if (type == ICMP_PARAMPROB) {
281 icp->icmp_pptr = code;
283 } else if (type == ICMP_UNREACH &&
284 code == ICMP_UNREACH_NEEDFRAG && mtu) {
285 icp->icmp_nextmtu = htons(mtu);
288 icp->icmp_code = code;
291 * Copy the quotation into ICMP message and
292 * convert quoted IP header back to network representation.
294 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
296 nip->ip_len = htons(nip->ip_len);
297 nip->ip_off = htons(nip->ip_off);
300 * Set up ICMP message mbuf and copy old IP header (without options
301 * in front of ICMP message.
302 * If the original mbuf was meant to bypass the firewall, the error
303 * reply should bypass as well.
305 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
306 m->m_data -= sizeof(struct ip);
307 m->m_len += sizeof(struct ip);
308 m->m_pkthdr.len = m->m_len;
309 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
310 nip = mtod(m, struct ip *);
311 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
312 nip->ip_len = m->m_len;
313 nip->ip_v = IPVERSION;
315 nip->ip_p = IPPROTO_ICMP;
324 * Process a received ICMP message.
327 icmp_input(struct mbuf *m, int off)
330 struct in_ifaddr *ia;
331 struct ip *ip = mtod(m, struct ip *);
332 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
334 int icmplen = ip->ip_len;
336 void (*ctlfunc)(int, struct sockaddr *, void *);
340 * Locate icmp structure in mbuf, and check
341 * that not corrupted and of at least minimum length.
345 char buf[4 * sizeof "123"];
346 strcpy(buf, inet_ntoa(ip->ip_src));
347 printf("icmp_input from %s to %s, len %d\n",
348 buf, inet_ntoa(ip->ip_dst), icmplen);
351 if (icmplen < ICMP_MINLEN) {
352 ICMPSTAT_INC(icps_tooshort);
355 i = hlen + min(icmplen, ICMP_ADVLENMIN);
356 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
357 ICMPSTAT_INC(icps_tooshort);
360 ip = mtod(m, struct ip *);
363 icp = mtod(m, struct icmp *);
364 if (in_cksum(m, icmplen)) {
365 ICMPSTAT_INC(icps_checksum);
371 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
373 * Deliver very specific ICMP type only.
375 switch (icp->icmp_type) {
386 printf("icmp_input, type %d code %d\n", icp->icmp_type,
391 * Message type specific processing.
393 if (icp->icmp_type > ICMP_MAXTYPE)
397 bzero(&icmpsrc, sizeof(icmpsrc));
398 icmpsrc.sin_len = sizeof(struct sockaddr_in);
399 icmpsrc.sin_family = AF_INET;
400 bzero(&icmpdst, sizeof(icmpdst));
401 icmpdst.sin_len = sizeof(struct sockaddr_in);
402 icmpdst.sin_family = AF_INET;
403 bzero(&icmpgw, sizeof(icmpgw));
404 icmpgw.sin_len = sizeof(struct sockaddr_in);
405 icmpgw.sin_family = AF_INET;
407 ICMPSTAT_INC(icps_inhist[icp->icmp_type]);
408 code = icp->icmp_code;
409 switch (icp->icmp_type) {
413 case ICMP_UNREACH_NET:
414 case ICMP_UNREACH_HOST:
415 case ICMP_UNREACH_SRCFAIL:
416 case ICMP_UNREACH_NET_UNKNOWN:
417 case ICMP_UNREACH_HOST_UNKNOWN:
418 case ICMP_UNREACH_ISOLATED:
419 case ICMP_UNREACH_TOSNET:
420 case ICMP_UNREACH_TOSHOST:
421 case ICMP_UNREACH_HOST_PRECEDENCE:
422 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
423 code = PRC_UNREACH_NET;
426 case ICMP_UNREACH_NEEDFRAG:
431 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
432 * Treat subcodes 2,3 as immediate RST
434 case ICMP_UNREACH_PROTOCOL:
435 case ICMP_UNREACH_PORT:
436 code = PRC_UNREACH_PORT;
439 case ICMP_UNREACH_NET_PROHIB:
440 case ICMP_UNREACH_HOST_PROHIB:
441 case ICMP_UNREACH_FILTER_PROHIB:
442 code = PRC_UNREACH_ADMIN_PROHIB;
453 code += PRC_TIMXCEED_INTRANS;
459 code = PRC_PARAMPROB;
462 case ICMP_SOURCEQUENCH:
468 * Problem with datagram; advise higher level routines.
470 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
471 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
472 ICMPSTAT_INC(icps_badlen);
475 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
476 /* Discard ICMP's in response to multicast packets */
477 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
481 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
483 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
485 * XXX if the packet contains [IPv4 AH TCP], we can't make a
486 * notification to TCP layer.
488 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
490 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
491 (void *)&icp->icmp_ip);
495 ICMPSTAT_INC(icps_badcode);
499 if (!V_icmpbmcastecho
500 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
501 ICMPSTAT_INC(icps_bmcastecho);
504 icp->icmp_type = ICMP_ECHOREPLY;
505 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
511 if (!V_icmpbmcastecho
512 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
513 ICMPSTAT_INC(icps_bmcasttstamp);
516 if (icmplen < ICMP_TSLEN) {
517 ICMPSTAT_INC(icps_badlen);
520 icp->icmp_type = ICMP_TSTAMPREPLY;
521 icp->icmp_rtime = iptime();
522 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
523 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
529 if (V_icmpmaskrepl == 0)
532 * We are not able to respond with all ones broadcast
533 * unless we receive it over a point-to-point interface.
535 if (icmplen < ICMP_MASKLEN)
537 switch (ip->ip_dst.s_addr) {
539 case INADDR_BROADCAST:
541 icmpdst.sin_addr = ip->ip_src;
545 icmpdst.sin_addr = ip->ip_dst;
547 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
548 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
551 if (ia->ia_ifp == NULL) {
552 ifa_free(&ia->ia_ifa);
555 icp->icmp_type = ICMP_MASKREPLY;
556 if (V_icmpmaskfake == 0)
557 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
559 icp->icmp_mask = V_icmpmaskfake;
560 if (ip->ip_src.s_addr == 0) {
561 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
562 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
563 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
564 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
566 ifa_free(&ia->ia_ifa);
568 ip->ip_len += hlen; /* since ip_input deducts this */
569 ICMPSTAT_INC(icps_reflect);
570 ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
575 if (V_log_redirect) {
578 src = ntohl(ip->ip_src.s_addr);
579 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
580 gw = ntohl(icp->icmp_gwaddr.s_addr);
581 printf("icmp redirect from %d.%d.%d.%d: "
582 "%d.%d.%d.%d => %d.%d.%d.%d\n",
583 (int)(src >> 24), (int)((src >> 16) & 0xff),
584 (int)((src >> 8) & 0xff), (int)(src & 0xff),
585 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
586 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
587 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
588 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
591 * RFC1812 says we must ignore ICMP redirects if we
592 * are acting as router.
594 if (V_drop_redirect || V_ipforwarding)
598 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
599 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
600 ICMPSTAT_INC(icps_badlen);
604 * Short circuit routing redirects to force
605 * immediate change in the kernel's routing
606 * tables. The message is also handed to anyone
607 * listening on a raw socket (e.g. the routing
608 * daemon for use in updating its tables).
610 icmpgw.sin_addr = ip->ip_src;
611 icmpdst.sin_addr = icp->icmp_gwaddr;
614 char buf[4 * sizeof "123"];
615 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
617 printf("redirect dst %s to %s\n",
618 buf, inet_ntoa(icp->icmp_gwaddr));
621 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
622 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
623 in_rtredirect((struct sockaddr *)&icmpsrc,
624 (struct sockaddr *)&icmpdst,
625 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
626 (struct sockaddr *)&icmpgw, fibnum);
628 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
630 key_sa_routechange((struct sockaddr *)&icmpsrc);
635 * No kernel processing for the following;
636 * just fall through to send to raw listener.
639 case ICMP_ROUTERADVERT:
640 case ICMP_ROUTERSOLICIT:
641 case ICMP_TSTAMPREPLY:
657 * Reflect the ip packet back to the source
660 icmp_reflect(struct mbuf *m)
662 struct ip *ip = mtod(m, struct ip *);
665 struct in_ifaddr *ia;
667 struct mbuf *opts = 0;
668 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
670 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
671 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) ||
672 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) {
673 m_freem(m); /* Bad return address */
674 ICMPSTAT_INC(icps_badaddr);
675 goto done; /* Ip_output() will check for broadcast */
681 ip->ip_dst = ip->ip_src;
684 * Source selection for ICMP replies:
686 * If the incoming packet was addressed directly to one of our
687 * own addresses, use dst as the src for the reply.
690 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
691 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
692 t = IA_SIN(ia)->sin_addr;
700 * If the incoming packet was addressed to one of our broadcast
701 * addresses, use the first non-broadcast address which corresponds
702 * to the incoming interface.
704 ifp = m->m_pkthdr.rcvif;
705 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
707 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
708 if (ifa->ifa_addr->sa_family != AF_INET)
711 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
713 t = IA_SIN(ia)->sin_addr;
721 * If the packet was transiting through us, use the address of
722 * the interface the packet came through in. If that interface
723 * doesn't have a suitable IP address, the normal selection
726 if (V_icmp_rfi && ifp != NULL) {
728 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
729 if (ifa->ifa_addr->sa_family != AF_INET)
732 t = IA_SIN(ia)->sin_addr;
739 * If the incoming packet was not addressed directly to us, use
740 * designated interface for icmp replies specified by sysctl
741 * net.inet.icmp.reply_src (default not set). Otherwise continue
742 * with normal source selection.
744 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
746 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
747 if (ifa->ifa_addr->sa_family != AF_INET)
750 t = IA_SIN(ia)->sin_addr;
757 * If the packet was transiting through us, use the address of
758 * the interface that is the closest to the packet source.
759 * When we don't have a route back to the packet source, stop here
760 * and drop the packet.
762 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
765 ICMPSTAT_INC(icps_noroute);
768 t = IA_SIN(ia)->sin_addr;
769 ifa_free(&ia->ia_ifa);
772 mac_netinet_icmp_replyinplace(m);
775 ip->ip_ttl = V_ip_defttl;
783 * Retrieve any source routing from the incoming packet;
784 * add on any record-route or timestamp options.
786 cp = (u_char *) (ip + 1);
787 if ((opts = ip_srcroute(m)) == 0 &&
788 (opts = m_gethdr(M_DONTWAIT, MT_DATA))) {
789 opts->m_len = sizeof(struct in_addr);
790 mtod(opts, struct in_addr *)->s_addr = 0;
795 printf("icmp_reflect optlen %d rt %d => ",
796 optlen, opts->m_len);
798 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
799 opt = cp[IPOPT_OPTVAL];
800 if (opt == IPOPT_EOL)
802 if (opt == IPOPT_NOP)
805 if (cnt < IPOPT_OLEN + sizeof(*cp))
807 len = cp[IPOPT_OLEN];
808 if (len < IPOPT_OLEN + sizeof(*cp) ||
813 * Should check for overflow, but it "can't happen"
815 if (opt == IPOPT_RR || opt == IPOPT_TS ||
816 opt == IPOPT_SECURITY) {
818 mtod(opts, caddr_t) + opts->m_len, len);
822 /* Terminate & pad, if necessary */
823 cnt = opts->m_len % 4;
825 for (; cnt < 4; cnt++) {
826 *(mtod(opts, caddr_t) + opts->m_len) =
833 printf("%d\n", opts->m_len);
837 * Now strip out original options by copying rest of first
838 * mbuf's data back, and adjust the IP length.
840 ip->ip_len -= optlen;
841 ip->ip_v = IPVERSION;
844 if (m->m_flags & M_PKTHDR)
845 m->m_pkthdr.len -= optlen;
846 optlen += sizeof(struct ip);
847 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
848 (unsigned)(m->m_len - sizeof(struct ip)));
850 m_tag_delete_nonpersistent(m);
851 m->m_flags &= ~(M_BCAST|M_MCAST);
859 * Send an icmp packet back to the ip level,
860 * after supplying a checksum.
863 icmp_send(struct mbuf *m, struct mbuf *opts)
865 register struct ip *ip = mtod(m, struct ip *);
867 register struct icmp *icp;
869 hlen = ip->ip_hl << 2;
872 icp = mtod(m, struct icmp *);
874 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
877 m->m_pkthdr.rcvif = (struct ifnet *)0;
880 char buf[4 * sizeof "123"];
881 strcpy(buf, inet_ntoa(ip->ip_dst));
882 printf("icmp_send dst %s src %s\n",
883 buf, inet_ntoa(ip->ip_src));
886 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
890 * Return milliseconds since 00:00 GMT in network format.
899 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
904 * Return the next larger or smaller MTU plateau (table from RFC 1191)
905 * given current value MTU. If DIR is less than zero, a larger plateau
906 * is returned; otherwise, a smaller value is returned.
909 ip_next_mtu(int mtu, int dir)
911 static int mtutab[] = {
912 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
917 size = (sizeof mtutab) / (sizeof mtutab[0]);
919 for (i = 0; i < size; i++)
923 for (i = size - 1; i >= 0; i--)
926 if (mtu == mtutab[0])
935 * badport_bandlim() - check for ICMP bandwidth limit
937 * Return 0 if it is ok to send an ICMP error response, -1 if we have
938 * hit our bandwidth limit and it is not ok.
940 * If icmplim is <= 0, the feature is disabled and 0 is returned.
942 * For now we separate the TCP and UDP subsystems w/ different 'which'
943 * values. We may eventually remove this separation (and simplify the
946 * Note that the printing of the error message is delayed so we can
947 * properly print the icmp error rate that the system was trying to do
948 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
949 * the 'final' error, but it doesn't make sense to solve the printing
950 * delay with more complex code.
954 badport_bandlim(int which)
957 #define N(a) (sizeof (a) / sizeof (a[0]))
960 struct timeval lasttime;
962 } rates[BANDLIM_MAX+1] = {
963 { "icmp unreach response" },
964 { "icmp ping response" },
965 { "icmp tstamp response" },
966 { "closed port RST response" },
967 { "open port RST response" },
968 { "icmp6 unreach response" }
972 * Return ok status if feature disabled or argument out of range.
974 if (V_icmplim > 0 && (u_int) which < N(rates)) {
975 struct rate *r = &rates[which];
976 int opps = r->curpps;
978 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim))
979 return -1; /* discard packet */
981 * If we've dropped below the threshold after having
982 * rate-limited traffic print the message. This preserves
983 * the previous behaviour at the expense of added complexity.
985 if (V_icmplim_output && opps > V_icmplim)
986 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n",
987 r->type, opps, V_icmplim);
989 return 0; /* okay to send packet */