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("$FreeBSD$");
35 #include "opt_ipsec.h"
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_types.h>
49 #include <net/route.h>
52 #include <netinet/in.h>
53 #include <netinet/in_pcb.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/in_var.h>
56 #include <netinet/ip.h>
57 #include <netinet/ip_icmp.h>
58 #include <netinet/ip_var.h>
59 #include <netinet/ip_options.h>
60 #include <netinet/tcp.h>
61 #include <netinet/tcp_var.h>
62 #include <netinet/tcpip.h>
63 #include <netinet/icmp_var.h>
66 #include <netipsec/ipsec.h>
67 #include <netipsec/key.h>
70 #include <machine/in_cksum.h>
72 #include <security/mac/mac_framework.h>
75 * ICMP routines: error generation, receive packet processing, and
76 * routines to turnaround packets back to the originator, and
77 * host table maintenance routines.
79 VNET_DEFINE(struct icmpstat, icmpstat);
80 SYSCTL_VNET_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW,
81 &VNET_NAME(icmpstat), icmpstat, "");
83 static VNET_DEFINE(int, icmpmaskrepl) = 0;
84 #define V_icmpmaskrepl VNET(icmpmaskrepl)
85 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
86 &VNET_NAME(icmpmaskrepl), 0,
87 "Reply to ICMP Address Mask Request packets.");
89 static VNET_DEFINE(u_int, icmpmaskfake) = 0;
90 #define V_icmpmaskfake VNET(icmpmaskfake)
91 SYSCTL_VNET_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_RW,
92 &VNET_NAME(icmpmaskfake), 0,
93 "Fake reply to ICMP Address Mask Request packets.");
95 VNET_DEFINE(int, drop_redirect) = 0;
97 static VNET_DEFINE(int, log_redirect) = 0;
98 #define V_log_redirect VNET(log_redirect)
99 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
100 &VNET_NAME(log_redirect), 0,
101 "Log ICMP redirects to the console");
103 static VNET_DEFINE(int, icmplim) = 200;
104 #define V_icmplim VNET(icmplim)
105 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
106 &VNET_NAME(icmplim), 0,
107 "Maximum number of ICMP responses per second");
109 static VNET_DEFINE(int, icmplim_output) = 1;
110 #define V_icmplim_output VNET(icmplim_output)
111 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
112 &VNET_NAME(icmplim_output), 0,
113 "Enable rate limiting of ICMP responses");
115 static VNET_DEFINE(char, reply_src[IFNAMSIZ]);
116 #define V_reply_src VNET(reply_src)
117 SYSCTL_VNET_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW,
118 &VNET_NAME(reply_src), IFNAMSIZ,
119 "icmp reply source for non-local packets.");
121 static VNET_DEFINE(int, icmp_rfi) = 0;
122 #define V_icmp_rfi VNET(icmp_rfi)
123 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW,
124 &VNET_NAME(icmp_rfi), 0,
125 "ICMP reply from incoming interface for non-local packets");
127 static VNET_DEFINE(int, icmp_quotelen) = 8;
128 #define V_icmp_quotelen VNET(icmp_quotelen)
129 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW,
130 &VNET_NAME(icmp_quotelen), 0,
131 "Number of bytes from original packet to quote in ICMP reply");
134 * ICMP broadcast echo sysctl
136 static VNET_DEFINE(int, icmpbmcastecho) = 0;
137 #define V_icmpbmcastecho VNET(icmpbmcastecho)
138 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
139 &VNET_NAME(icmpbmcastecho), 0,
147 static void icmp_reflect(struct mbuf *);
148 static void icmp_send(struct mbuf *, struct mbuf *);
150 extern struct protosw inetsw[];
153 sysctl_net_icmp_drop_redir(SYSCTL_HANDLER_ARGS)
157 struct radix_node_head *rnh;
159 new = V_drop_redirect;
160 error = sysctl_handle_int(oidp, &new, 0, req);
161 if (error == 0 && req->newptr) {
162 new = (new != 0) ? 1 : 0;
164 if (new == V_drop_redirect)
167 for (i = 0; i < rt_numfibs; i++) {
168 if ((rnh = rt_tables_get_rnh(i, AF_INET)) == NULL)
170 RADIX_NODE_HEAD_LOCK(rnh);
171 in_setmatchfunc(rnh, new);
172 RADIX_NODE_HEAD_UNLOCK(rnh);
175 V_drop_redirect = new;
181 SYSCTL_VNET_PROC(_net_inet_icmp, OID_AUTO, drop_redirect,
182 CTLTYPE_INT|CTLFLAG_RW, 0, 0,
183 sysctl_net_icmp_drop_redir, "I", "Ignore ICMP redirects");
186 * Kernel module interface for updating icmpstat. The argument is an index
187 * into icmpstat treated as an array of u_long. While this encodes the
188 * general layout of icmpstat into the caller, it doesn't encode its
189 * location, so that future changes to add, for example, per-CPU stats
190 * support won't cause binary compatibility problems for kernel modules.
193 kmod_icmpstat_inc(int statnum)
196 (*((u_long *)&V_icmpstat + statnum))++;
200 * Generate an error packet of type error
201 * in response to bad packet ip.
204 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
206 register struct ip *oip = mtod(n, struct ip *), *nip;
207 register unsigned oiphlen = oip->ip_hl << 2;
208 register struct icmp *icp;
209 register struct mbuf *m;
210 unsigned icmplen, icmpelen, nlen;
212 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
215 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
217 if (type != ICMP_REDIRECT)
218 ICMPSTAT_INC(icps_error);
221 * if the original packet was encrypted.
222 * if not the first fragment of message.
223 * in response to a multicast or broadcast packet.
224 * if the old packet protocol was an ICMP error message.
226 if (n->m_flags & M_DECRYPTED)
228 if (oip->ip_off & ~(IP_MF|IP_DF))
230 if (n->m_flags & (M_BCAST|M_MCAST))
232 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
233 n->m_len >= oiphlen + ICMP_MINLEN &&
234 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
235 ICMPSTAT_INC(icps_oldicmp);
238 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
239 if (oiphlen + 8 > n->m_len)
242 * Calculate length to quote from original packet and
243 * prevent the ICMP mbuf from overflowing.
244 * Unfortunatly this is non-trivial since ip_forward()
245 * sends us truncated packets.
247 nlen = m_length(n, NULL);
248 if (oip->ip_p == IPPROTO_TCP) {
252 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
255 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
256 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
258 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
259 tcphlen = th->th_off << 2;
260 if (tcphlen < sizeof(struct tcphdr))
262 if (oip->ip_len < oiphlen + tcphlen)
264 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
266 if (n->m_len < oiphlen + tcphlen &&
267 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
269 icmpelen = max(tcphlen, min(V_icmp_quotelen, oip->ip_len - oiphlen));
271 stdreply: icmpelen = max(8, min(V_icmp_quotelen, oip->ip_len - oiphlen));
273 icmplen = min(oiphlen + icmpelen, nlen);
274 if (icmplen < sizeof(struct ip))
277 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
278 m = m_gethdr(M_DONTWAIT, MT_DATA);
280 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
284 mac_netinet_icmp_reply(n, m);
286 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
287 m_align(m, ICMP_MINLEN + icmplen);
288 m->m_len = ICMP_MINLEN + icmplen;
290 /* XXX MRT make the outgoing packet use the same FIB
291 * that was associated with the incoming packet
293 M_SETFIB(m, M_GETFIB(n));
294 icp = mtod(m, struct icmp *);
295 ICMPSTAT_INC(icps_outhist[type]);
296 icp->icmp_type = type;
297 if (type == ICMP_REDIRECT)
298 icp->icmp_gwaddr.s_addr = dest;
302 * The following assignments assume an overlay with the
303 * just zeroed icmp_void field.
305 if (type == ICMP_PARAMPROB) {
306 icp->icmp_pptr = code;
308 } else if (type == ICMP_UNREACH &&
309 code == ICMP_UNREACH_NEEDFRAG && mtu) {
310 icp->icmp_nextmtu = htons(mtu);
313 icp->icmp_code = code;
316 * Copy the quotation into ICMP message and
317 * convert quoted IP header back to network representation.
319 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
321 nip->ip_len = htons(nip->ip_len);
322 nip->ip_off = htons(nip->ip_off);
325 * Set up ICMP message mbuf and copy old IP header (without options
326 * in front of ICMP message.
327 * If the original mbuf was meant to bypass the firewall, the error
328 * reply should bypass as well.
330 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
331 m->m_data -= sizeof(struct ip);
332 m->m_len += sizeof(struct ip);
333 m->m_pkthdr.len = m->m_len;
334 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
335 nip = mtod(m, struct ip *);
336 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
337 nip->ip_len = m->m_len;
338 nip->ip_v = IPVERSION;
340 nip->ip_p = IPPROTO_ICMP;
349 * Process a received ICMP message.
352 icmp_input(struct mbuf *m, int off)
355 struct in_ifaddr *ia;
356 struct ip *ip = mtod(m, struct ip *);
357 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
359 int icmplen = ip->ip_len;
361 void (*ctlfunc)(int, struct sockaddr *, void *);
365 * Locate icmp structure in mbuf, and check
366 * that not corrupted and of at least minimum length.
370 char buf[4 * sizeof "123"];
371 strcpy(buf, inet_ntoa(ip->ip_src));
372 printf("icmp_input from %s to %s, len %d\n",
373 buf, inet_ntoa(ip->ip_dst), icmplen);
376 if (icmplen < ICMP_MINLEN) {
377 ICMPSTAT_INC(icps_tooshort);
380 i = hlen + min(icmplen, ICMP_ADVLENMIN);
381 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
382 ICMPSTAT_INC(icps_tooshort);
385 ip = mtod(m, struct ip *);
388 icp = mtod(m, struct icmp *);
389 if (in_cksum(m, icmplen)) {
390 ICMPSTAT_INC(icps_checksum);
396 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
398 * Deliver very specific ICMP type only.
400 switch (icp->icmp_type) {
411 printf("icmp_input, type %d code %d\n", icp->icmp_type,
416 * Message type specific processing.
418 if (icp->icmp_type > ICMP_MAXTYPE)
422 bzero(&icmpsrc, sizeof(icmpsrc));
423 icmpsrc.sin_len = sizeof(struct sockaddr_in);
424 icmpsrc.sin_family = AF_INET;
425 bzero(&icmpdst, sizeof(icmpdst));
426 icmpdst.sin_len = sizeof(struct sockaddr_in);
427 icmpdst.sin_family = AF_INET;
428 bzero(&icmpgw, sizeof(icmpgw));
429 icmpgw.sin_len = sizeof(struct sockaddr_in);
430 icmpgw.sin_family = AF_INET;
432 ICMPSTAT_INC(icps_inhist[icp->icmp_type]);
433 code = icp->icmp_code;
434 switch (icp->icmp_type) {
438 case ICMP_UNREACH_NET:
439 case ICMP_UNREACH_HOST:
440 case ICMP_UNREACH_SRCFAIL:
441 case ICMP_UNREACH_NET_UNKNOWN:
442 case ICMP_UNREACH_HOST_UNKNOWN:
443 case ICMP_UNREACH_ISOLATED:
444 case ICMP_UNREACH_TOSNET:
445 case ICMP_UNREACH_TOSHOST:
446 case ICMP_UNREACH_HOST_PRECEDENCE:
447 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
448 code = PRC_UNREACH_NET;
451 case ICMP_UNREACH_NEEDFRAG:
456 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
457 * Treat subcodes 2,3 as immediate RST
459 case ICMP_UNREACH_PROTOCOL:
460 case ICMP_UNREACH_PORT:
461 code = PRC_UNREACH_PORT;
464 case ICMP_UNREACH_NET_PROHIB:
465 case ICMP_UNREACH_HOST_PROHIB:
466 case ICMP_UNREACH_FILTER_PROHIB:
467 code = PRC_UNREACH_ADMIN_PROHIB;
478 code += PRC_TIMXCEED_INTRANS;
484 code = PRC_PARAMPROB;
487 case ICMP_SOURCEQUENCH:
493 * Problem with datagram; advise higher level routines.
495 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
496 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
497 ICMPSTAT_INC(icps_badlen);
500 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
501 /* Discard ICMP's in response to multicast packets */
502 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
506 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
508 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
510 * XXX if the packet contains [IPv4 AH TCP], we can't make a
511 * notification to TCP layer.
513 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
515 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
516 (void *)&icp->icmp_ip);
520 ICMPSTAT_INC(icps_badcode);
524 if (!V_icmpbmcastecho
525 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
526 ICMPSTAT_INC(icps_bmcastecho);
529 icp->icmp_type = ICMP_ECHOREPLY;
530 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
536 if (!V_icmpbmcastecho
537 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
538 ICMPSTAT_INC(icps_bmcasttstamp);
541 if (icmplen < ICMP_TSLEN) {
542 ICMPSTAT_INC(icps_badlen);
545 icp->icmp_type = ICMP_TSTAMPREPLY;
546 icp->icmp_rtime = iptime();
547 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
548 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
554 if (V_icmpmaskrepl == 0)
557 * We are not able to respond with all ones broadcast
558 * unless we receive it over a point-to-point interface.
560 if (icmplen < ICMP_MASKLEN)
562 switch (ip->ip_dst.s_addr) {
564 case INADDR_BROADCAST:
566 icmpdst.sin_addr = ip->ip_src;
570 icmpdst.sin_addr = ip->ip_dst;
572 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
573 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
576 if (ia->ia_ifp == NULL) {
577 ifa_free(&ia->ia_ifa);
580 icp->icmp_type = ICMP_MASKREPLY;
581 if (V_icmpmaskfake == 0)
582 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
584 icp->icmp_mask = V_icmpmaskfake;
585 if (ip->ip_src.s_addr == 0) {
586 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
587 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
588 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
589 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
591 ifa_free(&ia->ia_ifa);
593 ip->ip_len += hlen; /* since ip_input deducts this */
594 ICMPSTAT_INC(icps_reflect);
595 ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
600 if (V_log_redirect) {
603 src = ntohl(ip->ip_src.s_addr);
604 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
605 gw = ntohl(icp->icmp_gwaddr.s_addr);
606 printf("icmp redirect from %d.%d.%d.%d: "
607 "%d.%d.%d.%d => %d.%d.%d.%d\n",
608 (int)(src >> 24), (int)((src >> 16) & 0xff),
609 (int)((src >> 8) & 0xff), (int)(src & 0xff),
610 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
611 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
612 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
613 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
616 * RFC1812 says we must ignore ICMP redirects if we
617 * are acting as router.
619 if (V_drop_redirect || V_ipforwarding)
623 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
624 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
625 ICMPSTAT_INC(icps_badlen);
629 * Short circuit routing redirects to force
630 * immediate change in the kernel's routing
631 * tables. The message is also handed to anyone
632 * listening on a raw socket (e.g. the routing
633 * daemon for use in updating its tables).
635 icmpgw.sin_addr = ip->ip_src;
636 icmpdst.sin_addr = icp->icmp_gwaddr;
639 char buf[4 * sizeof "123"];
640 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
642 printf("redirect dst %s to %s\n",
643 buf, inet_ntoa(icp->icmp_gwaddr));
646 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
647 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
648 in_rtredirect((struct sockaddr *)&icmpsrc,
649 (struct sockaddr *)&icmpdst,
650 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
651 (struct sockaddr *)&icmpgw, fibnum);
653 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
655 key_sa_routechange((struct sockaddr *)&icmpsrc);
660 * No kernel processing for the following;
661 * just fall through to send to raw listener.
664 case ICMP_ROUTERADVERT:
665 case ICMP_ROUTERSOLICIT:
666 case ICMP_TSTAMPREPLY:
682 * Reflect the ip packet back to the source
685 icmp_reflect(struct mbuf *m)
687 struct ip *ip = mtod(m, struct ip *);
690 struct in_ifaddr *ia;
692 struct mbuf *opts = 0;
693 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
695 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
696 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) ||
697 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) {
698 m_freem(m); /* Bad return address */
699 ICMPSTAT_INC(icps_badaddr);
700 goto done; /* Ip_output() will check for broadcast */
704 ip->ip_dst = ip->ip_src;
707 * Source selection for ICMP replies:
709 * If the incoming packet was addressed directly to one of our
710 * own addresses, use dst as the src for the reply.
713 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
714 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
715 t = IA_SIN(ia)->sin_addr;
723 * If the incoming packet was addressed to one of our broadcast
724 * addresses, use the first non-broadcast address which corresponds
725 * to the incoming interface.
727 ifp = m->m_pkthdr.rcvif;
728 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
730 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
731 if (ifa->ifa_addr->sa_family != AF_INET)
734 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
736 t = IA_SIN(ia)->sin_addr;
737 IF_ADDR_RUNLOCK(ifp);
741 IF_ADDR_RUNLOCK(ifp);
744 * If the packet was transiting through us, use the address of
745 * the interface the packet came through in. If that interface
746 * doesn't have a suitable IP address, the normal selection
749 if (V_icmp_rfi && ifp != NULL) {
751 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
752 if (ifa->ifa_addr->sa_family != AF_INET)
755 t = IA_SIN(ia)->sin_addr;
756 IF_ADDR_RUNLOCK(ifp);
759 IF_ADDR_RUNLOCK(ifp);
762 * If the incoming packet was not addressed directly to us, use
763 * designated interface for icmp replies specified by sysctl
764 * net.inet.icmp.reply_src (default not set). Otherwise continue
765 * with normal source selection.
767 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
769 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
770 if (ifa->ifa_addr->sa_family != AF_INET)
773 t = IA_SIN(ia)->sin_addr;
774 IF_ADDR_RUNLOCK(ifp);
777 IF_ADDR_RUNLOCK(ifp);
780 * If the packet was transiting through us, use the address of
781 * the interface that is the closest to the packet source.
782 * When we don't have a route back to the packet source, stop here
783 * and drop the packet.
785 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
788 ICMPSTAT_INC(icps_noroute);
791 t = IA_SIN(ia)->sin_addr;
792 ifa_free(&ia->ia_ifa);
795 mac_netinet_icmp_replyinplace(m);
798 ip->ip_ttl = V_ip_defttl;
806 * Retrieve any source routing from the incoming packet;
807 * add on any record-route or timestamp options.
809 cp = (u_char *) (ip + 1);
810 if ((opts = ip_srcroute(m)) == 0 &&
811 (opts = m_gethdr(M_DONTWAIT, MT_DATA))) {
812 opts->m_len = sizeof(struct in_addr);
813 mtod(opts, struct in_addr *)->s_addr = 0;
818 printf("icmp_reflect optlen %d rt %d => ",
819 optlen, opts->m_len);
821 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
822 opt = cp[IPOPT_OPTVAL];
823 if (opt == IPOPT_EOL)
825 if (opt == IPOPT_NOP)
828 if (cnt < IPOPT_OLEN + sizeof(*cp))
830 len = cp[IPOPT_OLEN];
831 if (len < IPOPT_OLEN + sizeof(*cp) ||
836 * Should check for overflow, but it "can't happen"
838 if (opt == IPOPT_RR || opt == IPOPT_TS ||
839 opt == IPOPT_SECURITY) {
841 mtod(opts, caddr_t) + opts->m_len, len);
845 /* Terminate & pad, if necessary */
846 cnt = opts->m_len % 4;
848 for (; cnt < 4; cnt++) {
849 *(mtod(opts, caddr_t) + opts->m_len) =
856 printf("%d\n", opts->m_len);
860 * Now strip out original options by copying rest of first
861 * mbuf's data back, and adjust the IP length.
863 ip->ip_len -= optlen;
864 ip->ip_v = IPVERSION;
867 if (m->m_flags & M_PKTHDR)
868 m->m_pkthdr.len -= optlen;
869 optlen += sizeof(struct ip);
870 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
871 (unsigned)(m->m_len - sizeof(struct ip)));
873 m_tag_delete_nonpersistent(m);
874 m->m_flags &= ~(M_BCAST|M_MCAST);
882 * Send an icmp packet back to the ip level,
883 * after supplying a checksum.
886 icmp_send(struct mbuf *m, struct mbuf *opts)
888 register struct ip *ip = mtod(m, struct ip *);
890 register struct icmp *icp;
892 hlen = ip->ip_hl << 2;
895 icp = mtod(m, struct icmp *);
897 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
900 m->m_pkthdr.rcvif = (struct ifnet *)0;
903 char buf[4 * sizeof "123"];
904 strcpy(buf, inet_ntoa(ip->ip_dst));
905 printf("icmp_send dst %s src %s\n",
906 buf, inet_ntoa(ip->ip_src));
909 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
913 * Return milliseconds since 00:00 GMT in network format.
922 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
927 * Return the next larger or smaller MTU plateau (table from RFC 1191)
928 * given current value MTU. If DIR is less than zero, a larger plateau
929 * is returned; otherwise, a smaller value is returned.
932 ip_next_mtu(int mtu, int dir)
934 static int mtutab[] = {
935 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
940 size = (sizeof mtutab) / (sizeof mtutab[0]);
942 for (i = 0; i < size; i++)
946 for (i = size - 1; i >= 0; i--)
949 if (mtu == mtutab[0])
957 * badport_bandlim() - check for ICMP bandwidth limit
959 * Return 0 if it is ok to send an ICMP error response, -1 if we have
960 * hit our bandwidth limit and it is not ok.
962 * If icmplim is <= 0, the feature is disabled and 0 is returned.
964 * For now we separate the TCP and UDP subsystems w/ different 'which'
965 * values. We may eventually remove this separation (and simplify the
968 * Note that the printing of the error message is delayed so we can
969 * properly print the icmp error rate that the system was trying to do
970 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
971 * the 'final' error, but it doesn't make sense to solve the printing
972 * delay with more complex code.
976 badport_bandlim(int which)
979 #define N(a) (sizeof (a) / sizeof (a[0]))
982 struct timeval lasttime;
984 } rates[BANDLIM_MAX+1] = {
985 { "icmp unreach response" },
986 { "icmp ping response" },
987 { "icmp tstamp response" },
988 { "closed port RST response" },
989 { "open port RST response" },
990 { "icmp6 unreach response" }
994 * Return ok status if feature disabled or argument out of range.
996 if (V_icmplim > 0 && (u_int) which < N(rates)) {
997 struct rate *r = &rates[which];
998 int opps = r->curpps;
1000 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim))
1001 return -1; /* discard packet */
1003 * If we've dropped below the threshold after having
1004 * rate-limited traffic print the message. This preserves
1005 * the previous behaviour at the expense of added complexity.
1007 if (V_icmplim_output && opps > V_icmplim)
1008 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n",
1009 r->type, opps, V_icmplim);
1011 return 0; /* okay to send packet */