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("$FreeBSD$");
37 #include <sys/param.h>
38 #include <sys/systm.h>
40 #include <sys/protosw.h>
41 #include <sys/socket.h>
43 #include <sys/kernel.h>
44 #include <sys/sysctl.h>
45 #include <sys/syslog.h>
48 #include <net/if_var.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 <machine/in_cksum.h>
70 #include <security/mac/mac_framework.h>
74 * ICMP routines: error generation, receive packet processing, and
75 * routines to turnaround packets back to the originator, and
76 * host table maintenance routines.
78 static VNET_DEFINE(int, icmplim) = 200;
79 #define V_icmplim VNET(icmplim)
80 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_VNET | CTLFLAG_RW,
81 &VNET_NAME(icmplim), 0,
82 "Maximum number of ICMP responses per second");
84 static VNET_DEFINE(int, icmplim_output) = 1;
85 #define V_icmplim_output VNET(icmplim_output)
86 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_VNET | CTLFLAG_RW,
87 &VNET_NAME(icmplim_output), 0,
88 "Enable logging of ICMP response rate limiting");
91 VNET_PCPUSTAT_DEFINE(struct icmpstat, icmpstat);
92 VNET_PCPUSTAT_SYSINIT(icmpstat);
93 SYSCTL_VNET_PCPUSTAT(_net_inet_icmp, ICMPCTL_STATS, stats, struct icmpstat,
94 icmpstat, "ICMP statistics (struct icmpstat, netinet/icmp_var.h)");
97 VNET_PCPUSTAT_SYSUNINIT(icmpstat);
100 static VNET_DEFINE(int, icmpmaskrepl) = 0;
101 #define V_icmpmaskrepl VNET(icmpmaskrepl)
102 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_VNET | CTLFLAG_RW,
103 &VNET_NAME(icmpmaskrepl), 0,
104 "Reply to ICMP Address Mask Request packets.");
106 static VNET_DEFINE(u_int, icmpmaskfake) = 0;
107 #define V_icmpmaskfake VNET(icmpmaskfake)
108 SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_VNET | CTLFLAG_RW,
109 &VNET_NAME(icmpmaskfake), 0,
110 "Fake reply to ICMP Address Mask Request packets.");
112 VNET_DEFINE(int, drop_redirect) = 0;
113 #define V_drop_redirect VNET(drop_redirect)
114 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_VNET | CTLFLAG_RW,
115 &VNET_NAME(drop_redirect), 0, "Ignore ICMP redirects");
117 static VNET_DEFINE(int, log_redirect) = 0;
118 #define V_log_redirect VNET(log_redirect)
119 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_VNET | 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_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_VNET | 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_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_VNET | 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_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_VNET | 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_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_VNET | CTLFLAG_RW,
147 &VNET_NAME(icmpbmcastecho), 0,
150 static VNET_DEFINE(int, icmptstamprepl) = 1;
151 #define V_icmptstamprepl VNET(icmptstamprepl)
152 SYSCTL_INT(_net_inet_icmp, OID_AUTO, tstamprepl, CTLFLAG_RW,
153 &VNET_NAME(icmptstamprepl), 0, "Respond to ICMP Timestamp packets");
159 static void icmp_reflect(struct mbuf *);
160 static void icmp_send(struct mbuf *, struct mbuf *);
162 extern struct protosw inetsw[];
165 * Kernel module interface for updating icmpstat. The argument is an index
166 * into icmpstat treated as an array of u_long. While this encodes the
167 * general layout of icmpstat into the caller, it doesn't encode its
168 * location, so that future changes to add, for example, per-CPU stats
169 * support won't cause binary compatibility problems for kernel modules.
172 kmod_icmpstat_inc(int statnum)
175 counter_u64_add(VNET(icmpstat)[statnum], 1);
179 * Generate an error packet of type error
180 * in response to bad packet ip.
183 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
185 register struct ip *oip = mtod(n, struct ip *), *nip;
186 register unsigned oiphlen = oip->ip_hl << 2;
187 register struct icmp *icp;
188 register struct mbuf *m;
189 unsigned icmplen, icmpelen, nlen;
191 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
194 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
196 if (type != ICMP_REDIRECT)
197 ICMPSTAT_INC(icps_error);
200 * if the original packet was encrypted.
201 * if not the first fragment of message.
202 * in response to a multicast or broadcast packet.
203 * if the old packet protocol was an ICMP error message.
205 if (n->m_flags & M_DECRYPTED)
207 if (oip->ip_off & htons(~(IP_MF|IP_DF)))
209 if (n->m_flags & (M_BCAST|M_MCAST))
211 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
212 n->m_len >= oiphlen + ICMP_MINLEN &&
213 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
214 ICMPSTAT_INC(icps_oldicmp);
217 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
218 if (oiphlen + 8 > n->m_len)
221 * Calculate length to quote from original packet and
222 * prevent the ICMP mbuf from overflowing.
223 * Unfortunatly this is non-trivial since ip_forward()
224 * sends us truncated packets.
226 nlen = m_length(n, NULL);
227 if (oip->ip_p == IPPROTO_TCP) {
231 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
234 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
235 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
237 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
238 tcphlen = th->th_off << 2;
239 if (tcphlen < sizeof(struct tcphdr))
241 if (ntohs(oip->ip_len) < oiphlen + tcphlen)
243 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
245 if (n->m_len < oiphlen + tcphlen &&
246 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
248 icmpelen = max(tcphlen, min(V_icmp_quotelen,
249 ntohs(oip->ip_len) - oiphlen));
251 stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen));
253 icmplen = min(oiphlen + icmpelen, nlen);
254 if (icmplen < sizeof(struct ip))
257 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
258 m = m_gethdr(M_NOWAIT, MT_DATA);
260 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
264 mac_netinet_icmp_reply(n, m);
266 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
267 m_align(m, ICMP_MINLEN + icmplen);
268 m->m_len = ICMP_MINLEN + icmplen;
270 /* XXX MRT make the outgoing packet use the same FIB
271 * that was associated with the incoming packet
273 M_SETFIB(m, M_GETFIB(n));
274 icp = mtod(m, struct icmp *);
275 ICMPSTAT_INC(icps_outhist[type]);
276 icp->icmp_type = type;
277 if (type == ICMP_REDIRECT)
278 icp->icmp_gwaddr.s_addr = dest;
282 * The following assignments assume an overlay with the
283 * just zeroed icmp_void field.
285 if (type == ICMP_PARAMPROB) {
286 icp->icmp_pptr = code;
288 } else if (type == ICMP_UNREACH &&
289 code == ICMP_UNREACH_NEEDFRAG && mtu) {
290 icp->icmp_nextmtu = htons(mtu);
293 icp->icmp_code = code;
296 * Copy the quotation into ICMP message and
297 * convert quoted IP header back to network representation.
299 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
303 * Set up ICMP message mbuf and copy old IP header (without options
304 * in front of ICMP message.
305 * If the original mbuf was meant to bypass the firewall, the error
306 * reply should bypass as well.
308 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
309 m->m_data -= sizeof(struct ip);
310 m->m_len += sizeof(struct ip);
311 m->m_pkthdr.len = m->m_len;
312 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
313 nip = mtod(m, struct ip *);
314 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
315 nip->ip_len = htons(m->m_len);
316 nip->ip_v = IPVERSION;
318 nip->ip_p = IPPROTO_ICMP;
328 * Process a received ICMP message.
331 icmp_input(struct mbuf **mp, int *offp, int proto)
334 struct in_ifaddr *ia;
335 struct mbuf *m = *mp;
336 struct ip *ip = mtod(m, struct ip *);
337 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
339 int icmplen = ntohs(ip->ip_len) - *offp;
341 void (*ctlfunc)(int, struct sockaddr *, void *);
347 * Locate icmp structure in mbuf, and check
348 * that not corrupted and of at least minimum length.
352 char buf[4 * sizeof "123"];
353 strcpy(buf, inet_ntoa(ip->ip_src));
354 printf("icmp_input from %s to %s, len %d\n",
355 buf, inet_ntoa(ip->ip_dst), icmplen);
358 if (icmplen < ICMP_MINLEN) {
359 ICMPSTAT_INC(icps_tooshort);
362 i = hlen + min(icmplen, ICMP_ADVLENMIN);
363 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
364 ICMPSTAT_INC(icps_tooshort);
365 return (IPPROTO_DONE);
367 ip = mtod(m, struct ip *);
370 icp = mtod(m, struct icmp *);
371 if (in_cksum(m, icmplen)) {
372 ICMPSTAT_INC(icps_checksum);
380 printf("icmp_input, type %d code %d\n", icp->icmp_type,
385 * Message type specific processing.
387 if (icp->icmp_type > ICMP_MAXTYPE)
391 bzero(&icmpsrc, sizeof(icmpsrc));
392 icmpsrc.sin_len = sizeof(struct sockaddr_in);
393 icmpsrc.sin_family = AF_INET;
394 bzero(&icmpdst, sizeof(icmpdst));
395 icmpdst.sin_len = sizeof(struct sockaddr_in);
396 icmpdst.sin_family = AF_INET;
397 bzero(&icmpgw, sizeof(icmpgw));
398 icmpgw.sin_len = sizeof(struct sockaddr_in);
399 icmpgw.sin_family = AF_INET;
401 ICMPSTAT_INC(icps_inhist[icp->icmp_type]);
402 code = icp->icmp_code;
403 switch (icp->icmp_type) {
407 case ICMP_UNREACH_NET:
408 case ICMP_UNREACH_HOST:
409 case ICMP_UNREACH_SRCFAIL:
410 case ICMP_UNREACH_NET_UNKNOWN:
411 case ICMP_UNREACH_HOST_UNKNOWN:
412 case ICMP_UNREACH_ISOLATED:
413 case ICMP_UNREACH_TOSNET:
414 case ICMP_UNREACH_TOSHOST:
415 case ICMP_UNREACH_HOST_PRECEDENCE:
416 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
417 code = PRC_UNREACH_NET;
420 case ICMP_UNREACH_NEEDFRAG:
425 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
426 * Treat subcodes 2,3 as immediate RST
428 case ICMP_UNREACH_PROTOCOL:
429 case ICMP_UNREACH_PORT:
430 code = PRC_UNREACH_PORT;
433 case ICMP_UNREACH_NET_PROHIB:
434 case ICMP_UNREACH_HOST_PROHIB:
435 case ICMP_UNREACH_FILTER_PROHIB:
436 code = PRC_UNREACH_ADMIN_PROHIB;
447 code += PRC_TIMXCEED_INTRANS;
453 code = PRC_PARAMPROB;
456 * Problem with datagram; advise higher level routines.
458 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
459 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
460 ICMPSTAT_INC(icps_badlen);
463 /* Discard ICMP's in response to multicast packets */
464 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
468 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
470 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
472 * XXX if the packet contains [IPv4 AH TCP], we can't make a
473 * notification to TCP layer.
475 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
477 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
478 (void *)&icp->icmp_ip);
482 ICMPSTAT_INC(icps_badcode);
486 if (!V_icmpbmcastecho
487 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
488 ICMPSTAT_INC(icps_bmcastecho);
491 icp->icmp_type = ICMP_ECHOREPLY;
492 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
498 if (V_icmptstamprepl == 0)
500 if (!V_icmpbmcastecho
501 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
502 ICMPSTAT_INC(icps_bmcasttstamp);
505 if (icmplen < ICMP_TSLEN) {
506 ICMPSTAT_INC(icps_badlen);
509 icp->icmp_type = ICMP_TSTAMPREPLY;
510 icp->icmp_rtime = iptime();
511 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
512 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
518 if (V_icmpmaskrepl == 0)
521 * We are not able to respond with all ones broadcast
522 * unless we receive it over a point-to-point interface.
524 if (icmplen < ICMP_MASKLEN)
526 switch (ip->ip_dst.s_addr) {
528 case INADDR_BROADCAST:
530 icmpdst.sin_addr = ip->ip_src;
534 icmpdst.sin_addr = ip->ip_dst;
536 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
537 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
540 if (ia->ia_ifp == NULL) {
541 ifa_free(&ia->ia_ifa);
544 icp->icmp_type = ICMP_MASKREPLY;
545 if (V_icmpmaskfake == 0)
546 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
548 icp->icmp_mask = V_icmpmaskfake;
549 if (ip->ip_src.s_addr == 0) {
550 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
551 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
552 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
553 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
555 ifa_free(&ia->ia_ifa);
557 ICMPSTAT_INC(icps_reflect);
558 ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
560 return (IPPROTO_DONE);
563 if (V_log_redirect) {
566 src = ntohl(ip->ip_src.s_addr);
567 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
568 gw = ntohl(icp->icmp_gwaddr.s_addr);
569 printf("icmp redirect from %d.%d.%d.%d: "
570 "%d.%d.%d.%d => %d.%d.%d.%d\n",
571 (int)(src >> 24), (int)((src >> 16) & 0xff),
572 (int)((src >> 8) & 0xff), (int)(src & 0xff),
573 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
574 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
575 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
576 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
579 * RFC1812 says we must ignore ICMP redirects if we
580 * are acting as router.
582 if (V_drop_redirect || V_ipforwarding)
586 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
587 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
588 ICMPSTAT_INC(icps_badlen);
592 * Short circuit routing redirects to force
593 * immediate change in the kernel's routing
594 * tables. The message is also handed to anyone
595 * listening on a raw socket (e.g. the routing
596 * daemon for use in updating its tables).
598 icmpgw.sin_addr = ip->ip_src;
599 icmpdst.sin_addr = icp->icmp_gwaddr;
602 char buf[4 * sizeof "123"];
603 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
605 printf("redirect dst %s to %s\n",
606 buf, inet_ntoa(icp->icmp_gwaddr));
609 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
610 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
611 in_rtredirect((struct sockaddr *)&icmpsrc,
612 (struct sockaddr *)&icmpdst,
613 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
614 (struct sockaddr *)&icmpgw, fibnum);
616 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
620 * No kernel processing for the following;
621 * just fall through to send to raw listener.
624 case ICMP_ROUTERADVERT:
625 case ICMP_ROUTERSOLICIT:
626 case ICMP_TSTAMPREPLY:
629 case ICMP_SOURCEQUENCH:
636 rip_input(mp, offp, proto);
637 return (IPPROTO_DONE);
641 return (IPPROTO_DONE);
645 * Reflect the ip packet back to the source
648 icmp_reflect(struct mbuf *m)
650 struct ip *ip = mtod(m, struct ip *);
653 struct in_ifaddr *ia;
655 struct mbuf *opts = 0;
656 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
658 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
659 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) ||
660 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) {
661 m_freem(m); /* Bad return address */
662 ICMPSTAT_INC(icps_badaddr);
663 goto done; /* Ip_output() will check for broadcast */
667 ip->ip_dst = ip->ip_src;
670 * Source selection for ICMP replies:
672 * If the incoming packet was addressed directly to one of our
673 * own addresses, use dst as the src for the reply.
676 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
677 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
678 t = IA_SIN(ia)->sin_addr;
686 * If the incoming packet was addressed to one of our broadcast
687 * addresses, use the first non-broadcast address which corresponds
688 * to the incoming interface.
690 ifp = m->m_pkthdr.rcvif;
691 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
693 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
694 if (ifa->ifa_addr->sa_family != AF_INET)
697 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
699 t = IA_SIN(ia)->sin_addr;
700 IF_ADDR_RUNLOCK(ifp);
704 IF_ADDR_RUNLOCK(ifp);
707 * If the packet was transiting through us, use the address of
708 * the interface the packet came through in. If that interface
709 * doesn't have a suitable IP address, the normal selection
712 if (V_icmp_rfi && ifp != NULL) {
714 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
715 if (ifa->ifa_addr->sa_family != AF_INET)
718 t = IA_SIN(ia)->sin_addr;
719 IF_ADDR_RUNLOCK(ifp);
722 IF_ADDR_RUNLOCK(ifp);
725 * If the incoming packet was not addressed directly to us, use
726 * designated interface for icmp replies specified by sysctl
727 * net.inet.icmp.reply_src (default not set). Otherwise continue
728 * with normal source selection.
730 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
732 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
733 if (ifa->ifa_addr->sa_family != AF_INET)
736 t = IA_SIN(ia)->sin_addr;
737 IF_ADDR_RUNLOCK(ifp);
740 IF_ADDR_RUNLOCK(ifp);
743 * If the packet was transiting through us, use the address of
744 * the interface that is the closest to the packet source.
745 * When we don't have a route back to the packet source, stop here
746 * and drop the packet.
748 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
751 ICMPSTAT_INC(icps_noroute);
754 t = IA_SIN(ia)->sin_addr;
755 ifa_free(&ia->ia_ifa);
758 mac_netinet_icmp_replyinplace(m);
761 ip->ip_ttl = V_ip_defttl;
769 * Retrieve any source routing from the incoming packet;
770 * add on any record-route or timestamp options.
772 cp = (u_char *) (ip + 1);
773 if ((opts = ip_srcroute(m)) == 0 &&
774 (opts = m_gethdr(M_NOWAIT, MT_DATA))) {
775 opts->m_len = sizeof(struct in_addr);
776 mtod(opts, struct in_addr *)->s_addr = 0;
781 printf("icmp_reflect optlen %d rt %d => ",
782 optlen, opts->m_len);
784 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
785 opt = cp[IPOPT_OPTVAL];
786 if (opt == IPOPT_EOL)
788 if (opt == IPOPT_NOP)
791 if (cnt < IPOPT_OLEN + sizeof(*cp))
793 len = cp[IPOPT_OLEN];
794 if (len < IPOPT_OLEN + sizeof(*cp) ||
799 * Should check for overflow, but it "can't happen"
801 if (opt == IPOPT_RR || opt == IPOPT_TS ||
802 opt == IPOPT_SECURITY) {
804 mtod(opts, caddr_t) + opts->m_len, len);
808 /* Terminate & pad, if necessary */
809 cnt = opts->m_len % 4;
811 for (; cnt < 4; cnt++) {
812 *(mtod(opts, caddr_t) + opts->m_len) =
819 printf("%d\n", opts->m_len);
824 m_tag_delete_nonpersistent(m);
825 m->m_flags &= ~(M_BCAST|M_MCAST);
833 * Send an icmp packet back to the ip level,
834 * after supplying a checksum.
837 icmp_send(struct mbuf *m, struct mbuf *opts)
839 register struct ip *ip = mtod(m, struct ip *);
841 register struct icmp *icp;
843 hlen = ip->ip_hl << 2;
846 icp = mtod(m, struct icmp *);
848 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
851 m->m_pkthdr.rcvif = (struct ifnet *)0;
854 char buf[4 * sizeof "123"];
855 strcpy(buf, inet_ntoa(ip->ip_dst));
856 printf("icmp_send dst %s src %s\n",
857 buf, inet_ntoa(ip->ip_src));
860 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
864 * Return milliseconds since 00:00 UTC in network format.
873 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
878 * Return the next larger or smaller MTU plateau (table from RFC 1191)
879 * given current value MTU. If DIR is less than zero, a larger plateau
880 * is returned; otherwise, a smaller value is returned.
883 ip_next_mtu(int mtu, int dir)
885 static int mtutab[] = {
886 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
891 size = (sizeof mtutab) / (sizeof mtutab[0]);
893 for (i = 0; i < size; i++)
897 for (i = size - 1; i >= 0; i--)
900 if (mtu == mtutab[0])
909 * badport_bandlim() - check for ICMP bandwidth limit
911 * Return 0 if it is ok to send an ICMP error response, -1 if we have
912 * hit our bandwidth limit and it is not ok.
914 * If icmplim is <= 0, the feature is disabled and 0 is returned.
916 * For now we separate the TCP and UDP subsystems w/ different 'which'
917 * values. We may eventually remove this separation (and simplify the
920 * Note that the printing of the error message is delayed so we can
921 * properly print the icmp error rate that the system was trying to do
922 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
923 * the 'final' error, but it doesn't make sense to solve the printing
924 * delay with more complex code.
928 badport_bandlim(int which)
931 #define N(a) (sizeof (a) / sizeof (a[0]))
934 struct timeval lasttime;
936 } rates[BANDLIM_MAX+1] = {
937 { "icmp unreach response" },
938 { "icmp ping response" },
939 { "icmp tstamp response" },
940 { "closed port RST response" },
941 { "open port RST response" },
942 { "icmp6 unreach response" },
943 { "sctp ootb response" }
947 * Return ok status if feature disabled or argument out of range.
949 if (V_icmplim > 0 && (u_int) which < N(rates)) {
950 struct rate *r = &rates[which];
951 int opps = r->curpps;
953 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim))
954 return -1; /* discard packet */
956 * If we've dropped below the threshold after having
957 * rate-limited traffic print the message. This preserves
958 * the previous behaviour at the expense of added complexity.
960 if (V_icmplim_output && opps > V_icmplim)
961 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n",
962 r->type, opps, V_icmplim);
964 return 0; /* okay to send packet */