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 VNET_DEFINE(int, drop_redirect) = 0;
113 static VNET_DEFINE(int, log_redirect) = 0;
114 #define V_log_redirect VNET(log_redirect)
115 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
116 &VNET_NAME(log_redirect), 0,
117 "Log ICMP redirects to the console");
119 static VNET_DEFINE(char, reply_src[IFNAMSIZ]);
120 #define V_reply_src VNET(reply_src)
121 SYSCTL_VNET_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW,
122 &VNET_NAME(reply_src), IFNAMSIZ,
123 "icmp reply source for non-local packets.");
125 static VNET_DEFINE(int, icmp_rfi) = 0;
126 #define V_icmp_rfi VNET(icmp_rfi)
127 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW,
128 &VNET_NAME(icmp_rfi), 0,
129 "ICMP reply from incoming interface for non-local packets");
131 static VNET_DEFINE(int, icmp_quotelen) = 8;
132 #define V_icmp_quotelen VNET(icmp_quotelen)
133 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_RW,
134 &VNET_NAME(icmp_quotelen), 0,
135 "Number of bytes from original packet to quote in ICMP reply");
138 * ICMP broadcast echo sysctl
140 static VNET_DEFINE(int, icmpbmcastecho) = 0;
141 #define V_icmpbmcastecho VNET(icmpbmcastecho)
142 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
143 &VNET_NAME(icmpbmcastecho), 0,
151 static void icmp_reflect(struct mbuf *);
152 static void icmp_send(struct mbuf *, struct mbuf *);
154 extern struct protosw inetsw[];
157 sysctl_net_icmp_drop_redir(SYSCTL_HANDLER_ARGS)
161 struct radix_node_head *rnh;
163 new = V_drop_redirect;
164 error = sysctl_handle_int(oidp, &new, 0, req);
165 if (error == 0 && req->newptr) {
166 new = (new != 0) ? 1 : 0;
168 if (new == V_drop_redirect)
171 for (i = 0; i < rt_numfibs; i++) {
172 if ((rnh = rt_tables_get_rnh(i, AF_INET)) == NULL)
174 RADIX_NODE_HEAD_LOCK(rnh);
175 in_setmatchfunc(rnh, new);
176 RADIX_NODE_HEAD_UNLOCK(rnh);
179 V_drop_redirect = new;
185 SYSCTL_VNET_PROC(_net_inet_icmp, OID_AUTO, drop_redirect,
186 CTLTYPE_INT|CTLFLAG_RW, 0, 0,
187 sysctl_net_icmp_drop_redir, "I", "Ignore ICMP redirects");
190 * Kernel module interface for updating icmpstat. The argument is an index
191 * into icmpstat treated as an array of u_long. While this encodes the
192 * general layout of icmpstat into the caller, it doesn't encode its
193 * location, so that future changes to add, for example, per-CPU stats
194 * support won't cause binary compatibility problems for kernel modules.
197 kmod_icmpstat_inc(int statnum)
200 (*((u_long *)&V_icmpstat + statnum))++;
204 * Generate an error packet of type error
205 * in response to bad packet ip.
208 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
210 register struct ip *oip = mtod(n, struct ip *), *nip;
211 register unsigned oiphlen = oip->ip_hl << 2;
212 register struct icmp *icp;
213 register struct mbuf *m;
214 unsigned icmplen, icmpelen, nlen;
216 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
219 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
221 if (type != ICMP_REDIRECT)
222 ICMPSTAT_INC(icps_error);
225 * if the original packet was encrypted.
226 * if not the first fragment of message.
227 * in response to a multicast or broadcast packet.
228 * if the old packet protocol was an ICMP error message.
230 if (n->m_flags & M_DECRYPTED)
232 if (oip->ip_off & ~(IP_MF|IP_DF))
234 if (n->m_flags & (M_BCAST|M_MCAST))
236 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
237 n->m_len >= oiphlen + ICMP_MINLEN &&
238 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
239 ICMPSTAT_INC(icps_oldicmp);
242 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
243 if (oiphlen + 8 > n->m_len)
246 * Calculate length to quote from original packet and
247 * prevent the ICMP mbuf from overflowing.
248 * Unfortunatly this is non-trivial since ip_forward()
249 * sends us truncated packets.
251 nlen = m_length(n, NULL);
252 if (oip->ip_p == IPPROTO_TCP) {
256 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
259 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
260 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
262 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
263 tcphlen = th->th_off << 2;
264 if (tcphlen < sizeof(struct tcphdr))
266 if (oip->ip_len < oiphlen + tcphlen)
268 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
270 if (n->m_len < oiphlen + tcphlen &&
271 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
273 icmpelen = max(tcphlen, min(V_icmp_quotelen, oip->ip_len - oiphlen));
275 stdreply: icmpelen = max(8, min(V_icmp_quotelen, oip->ip_len - oiphlen));
277 icmplen = min(oiphlen + icmpelen, nlen);
278 if (icmplen < sizeof(struct ip))
281 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
282 m = m_gethdr(M_DONTWAIT, MT_DATA);
284 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
288 mac_netinet_icmp_reply(n, m);
290 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
291 m_align(m, ICMP_MINLEN + icmplen);
292 m->m_len = ICMP_MINLEN + icmplen;
294 /* XXX MRT make the outgoing packet use the same FIB
295 * that was associated with the incoming packet
297 M_SETFIB(m, M_GETFIB(n));
298 icp = mtod(m, struct icmp *);
299 ICMPSTAT_INC(icps_outhist[type]);
300 icp->icmp_type = type;
301 if (type == ICMP_REDIRECT)
302 icp->icmp_gwaddr.s_addr = dest;
306 * The following assignments assume an overlay with the
307 * just zeroed icmp_void field.
309 if (type == ICMP_PARAMPROB) {
310 icp->icmp_pptr = code;
312 } else if (type == ICMP_UNREACH &&
313 code == ICMP_UNREACH_NEEDFRAG && mtu) {
314 icp->icmp_nextmtu = htons(mtu);
317 icp->icmp_code = code;
320 * Copy the quotation into ICMP message and
321 * convert quoted IP header back to network representation.
323 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
325 nip->ip_len = htons(nip->ip_len);
326 nip->ip_off = htons(nip->ip_off);
329 * Set up ICMP message mbuf and copy old IP header (without options
330 * in front of ICMP message.
331 * If the original mbuf was meant to bypass the firewall, the error
332 * reply should bypass as well.
334 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
335 m->m_data -= sizeof(struct ip);
336 m->m_len += sizeof(struct ip);
337 m->m_pkthdr.len = m->m_len;
338 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
339 nip = mtod(m, struct ip *);
340 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
341 nip->ip_len = m->m_len;
342 nip->ip_v = IPVERSION;
344 nip->ip_p = IPPROTO_ICMP;
354 * Process a received ICMP message.
357 icmp_input(struct mbuf *m, int off)
360 struct in_ifaddr *ia;
361 struct ip *ip = mtod(m, struct ip *);
362 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
364 int icmplen = ip->ip_len;
366 void (*ctlfunc)(int, struct sockaddr *, void *);
370 * Locate icmp structure in mbuf, and check
371 * that not corrupted and of at least minimum length.
375 char buf[4 * sizeof "123"];
376 strcpy(buf, inet_ntoa(ip->ip_src));
377 printf("icmp_input from %s to %s, len %d\n",
378 buf, inet_ntoa(ip->ip_dst), icmplen);
381 if (icmplen < ICMP_MINLEN) {
382 ICMPSTAT_INC(icps_tooshort);
385 i = hlen + min(icmplen, ICMP_ADVLENMIN);
386 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
387 ICMPSTAT_INC(icps_tooshort);
390 ip = mtod(m, struct ip *);
393 icp = mtod(m, struct icmp *);
394 if (in_cksum(m, icmplen)) {
395 ICMPSTAT_INC(icps_checksum);
401 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
403 * Deliver very specific ICMP type only.
405 switch (icp->icmp_type) {
416 printf("icmp_input, type %d code %d\n", icp->icmp_type,
421 * Message type specific processing.
423 if (icp->icmp_type > ICMP_MAXTYPE)
427 bzero(&icmpsrc, sizeof(icmpsrc));
428 icmpsrc.sin_len = sizeof(struct sockaddr_in);
429 icmpsrc.sin_family = AF_INET;
430 bzero(&icmpdst, sizeof(icmpdst));
431 icmpdst.sin_len = sizeof(struct sockaddr_in);
432 icmpdst.sin_family = AF_INET;
433 bzero(&icmpgw, sizeof(icmpgw));
434 icmpgw.sin_len = sizeof(struct sockaddr_in);
435 icmpgw.sin_family = AF_INET;
437 ICMPSTAT_INC(icps_inhist[icp->icmp_type]);
438 code = icp->icmp_code;
439 switch (icp->icmp_type) {
443 case ICMP_UNREACH_NET:
444 case ICMP_UNREACH_HOST:
445 case ICMP_UNREACH_SRCFAIL:
446 case ICMP_UNREACH_NET_UNKNOWN:
447 case ICMP_UNREACH_HOST_UNKNOWN:
448 case ICMP_UNREACH_ISOLATED:
449 case ICMP_UNREACH_TOSNET:
450 case ICMP_UNREACH_TOSHOST:
451 case ICMP_UNREACH_HOST_PRECEDENCE:
452 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
453 code = PRC_UNREACH_NET;
456 case ICMP_UNREACH_NEEDFRAG:
461 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
462 * Treat subcodes 2,3 as immediate RST
464 case ICMP_UNREACH_PROTOCOL:
465 case ICMP_UNREACH_PORT:
466 code = PRC_UNREACH_PORT;
469 case ICMP_UNREACH_NET_PROHIB:
470 case ICMP_UNREACH_HOST_PROHIB:
471 case ICMP_UNREACH_FILTER_PROHIB:
472 code = PRC_UNREACH_ADMIN_PROHIB;
483 code += PRC_TIMXCEED_INTRANS;
489 code = PRC_PARAMPROB;
492 case ICMP_SOURCEQUENCH:
498 * Problem with datagram; advise higher level routines.
500 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
501 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
502 ICMPSTAT_INC(icps_badlen);
505 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
506 /* Discard ICMP's in response to multicast packets */
507 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
511 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
513 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
515 * XXX if the packet contains [IPv4 AH TCP], we can't make a
516 * notification to TCP layer.
518 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
520 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
521 (void *)&icp->icmp_ip);
525 ICMPSTAT_INC(icps_badcode);
529 if (!V_icmpbmcastecho
530 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
531 ICMPSTAT_INC(icps_bmcastecho);
534 icp->icmp_type = ICMP_ECHOREPLY;
535 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
541 if (!V_icmpbmcastecho
542 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
543 ICMPSTAT_INC(icps_bmcasttstamp);
546 if (icmplen < ICMP_TSLEN) {
547 ICMPSTAT_INC(icps_badlen);
550 icp->icmp_type = ICMP_TSTAMPREPLY;
551 icp->icmp_rtime = iptime();
552 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
553 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
559 if (V_icmpmaskrepl == 0)
562 * We are not able to respond with all ones broadcast
563 * unless we receive it over a point-to-point interface.
565 if (icmplen < ICMP_MASKLEN)
567 switch (ip->ip_dst.s_addr) {
569 case INADDR_BROADCAST:
571 icmpdst.sin_addr = ip->ip_src;
575 icmpdst.sin_addr = ip->ip_dst;
577 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
578 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
581 if (ia->ia_ifp == NULL) {
582 ifa_free(&ia->ia_ifa);
585 icp->icmp_type = ICMP_MASKREPLY;
586 if (V_icmpmaskfake == 0)
587 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
589 icp->icmp_mask = V_icmpmaskfake;
590 if (ip->ip_src.s_addr == 0) {
591 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
592 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
593 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
594 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
596 ifa_free(&ia->ia_ifa);
598 ip->ip_len += hlen; /* since ip_input deducts this */
599 ICMPSTAT_INC(icps_reflect);
600 ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
605 if (V_log_redirect) {
608 src = ntohl(ip->ip_src.s_addr);
609 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
610 gw = ntohl(icp->icmp_gwaddr.s_addr);
611 printf("icmp redirect from %d.%d.%d.%d: "
612 "%d.%d.%d.%d => %d.%d.%d.%d\n",
613 (int)(src >> 24), (int)((src >> 16) & 0xff),
614 (int)((src >> 8) & 0xff), (int)(src & 0xff),
615 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
616 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
617 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
618 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
621 * RFC1812 says we must ignore ICMP redirects if we
622 * are acting as router.
624 if (V_drop_redirect || V_ipforwarding)
628 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
629 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
630 ICMPSTAT_INC(icps_badlen);
634 * Short circuit routing redirects to force
635 * immediate change in the kernel's routing
636 * tables. The message is also handed to anyone
637 * listening on a raw socket (e.g. the routing
638 * daemon for use in updating its tables).
640 icmpgw.sin_addr = ip->ip_src;
641 icmpdst.sin_addr = icp->icmp_gwaddr;
644 char buf[4 * sizeof "123"];
645 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
647 printf("redirect dst %s to %s\n",
648 buf, inet_ntoa(icp->icmp_gwaddr));
651 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
652 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
653 in_rtredirect((struct sockaddr *)&icmpsrc,
654 (struct sockaddr *)&icmpdst,
655 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
656 (struct sockaddr *)&icmpgw, fibnum);
658 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
660 key_sa_routechange((struct sockaddr *)&icmpsrc);
665 * No kernel processing for the following;
666 * just fall through to send to raw listener.
669 case ICMP_ROUTERADVERT:
670 case ICMP_ROUTERSOLICIT:
671 case ICMP_TSTAMPREPLY:
687 * Reflect the ip packet back to the source
690 icmp_reflect(struct mbuf *m)
692 struct ip *ip = mtod(m, struct ip *);
695 struct in_ifaddr *ia;
697 struct mbuf *opts = 0;
698 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
700 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
701 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) ||
702 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) {
703 m_freem(m); /* Bad return address */
704 ICMPSTAT_INC(icps_badaddr);
705 goto done; /* Ip_output() will check for broadcast */
711 ip->ip_dst = ip->ip_src;
714 * Source selection for ICMP replies:
716 * If the incoming packet was addressed directly to one of our
717 * own addresses, use dst as the src for the reply.
720 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
721 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
722 t = IA_SIN(ia)->sin_addr;
730 * If the incoming packet was addressed to one of our broadcast
731 * addresses, use the first non-broadcast address which corresponds
732 * to the incoming interface.
734 ifp = m->m_pkthdr.rcvif;
735 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
737 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
738 if (ifa->ifa_addr->sa_family != AF_INET)
741 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
743 t = IA_SIN(ia)->sin_addr;
744 IF_ADDR_RUNLOCK(ifp);
748 IF_ADDR_RUNLOCK(ifp);
751 * If the packet was transiting through us, use the address of
752 * the interface the packet came through in. If that interface
753 * doesn't have a suitable IP address, the normal selection
756 if (V_icmp_rfi && ifp != NULL) {
758 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
759 if (ifa->ifa_addr->sa_family != AF_INET)
762 t = IA_SIN(ia)->sin_addr;
763 IF_ADDR_RUNLOCK(ifp);
766 IF_ADDR_RUNLOCK(ifp);
769 * If the incoming packet was not addressed directly to us, use
770 * designated interface for icmp replies specified by sysctl
771 * net.inet.icmp.reply_src (default not set). Otherwise continue
772 * with normal source selection.
774 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
776 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
777 if (ifa->ifa_addr->sa_family != AF_INET)
780 t = IA_SIN(ia)->sin_addr;
781 IF_ADDR_RUNLOCK(ifp);
784 IF_ADDR_RUNLOCK(ifp);
787 * If the packet was transiting through us, use the address of
788 * the interface that is the closest to the packet source.
789 * When we don't have a route back to the packet source, stop here
790 * and drop the packet.
792 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
795 ICMPSTAT_INC(icps_noroute);
798 t = IA_SIN(ia)->sin_addr;
799 ifa_free(&ia->ia_ifa);
802 mac_netinet_icmp_replyinplace(m);
805 ip->ip_ttl = V_ip_defttl;
813 * Retrieve any source routing from the incoming packet;
814 * add on any record-route or timestamp options.
816 cp = (u_char *) (ip + 1);
817 if ((opts = ip_srcroute(m)) == 0 &&
818 (opts = m_gethdr(M_DONTWAIT, MT_DATA))) {
819 opts->m_len = sizeof(struct in_addr);
820 mtod(opts, struct in_addr *)->s_addr = 0;
825 printf("icmp_reflect optlen %d rt %d => ",
826 optlen, opts->m_len);
828 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
829 opt = cp[IPOPT_OPTVAL];
830 if (opt == IPOPT_EOL)
832 if (opt == IPOPT_NOP)
835 if (cnt < IPOPT_OLEN + sizeof(*cp))
837 len = cp[IPOPT_OLEN];
838 if (len < IPOPT_OLEN + sizeof(*cp) ||
843 * Should check for overflow, but it "can't happen"
845 if (opt == IPOPT_RR || opt == IPOPT_TS ||
846 opt == IPOPT_SECURITY) {
848 mtod(opts, caddr_t) + opts->m_len, len);
852 /* Terminate & pad, if necessary */
853 cnt = opts->m_len % 4;
855 for (; cnt < 4; cnt++) {
856 *(mtod(opts, caddr_t) + opts->m_len) =
863 printf("%d\n", opts->m_len);
867 * Now strip out original options by copying rest of first
868 * mbuf's data back, and adjust the IP length.
870 ip->ip_len -= optlen;
871 ip->ip_v = IPVERSION;
874 if (m->m_flags & M_PKTHDR)
875 m->m_pkthdr.len -= optlen;
876 optlen += sizeof(struct ip);
877 bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
878 (unsigned)(m->m_len - sizeof(struct ip)));
880 m_tag_delete_nonpersistent(m);
881 m->m_flags &= ~(M_BCAST|M_MCAST);
889 * Send an icmp packet back to the ip level,
890 * after supplying a checksum.
893 icmp_send(struct mbuf *m, struct mbuf *opts)
895 register struct ip *ip = mtod(m, struct ip *);
897 register struct icmp *icp;
899 hlen = ip->ip_hl << 2;
902 icp = mtod(m, struct icmp *);
904 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
907 m->m_pkthdr.rcvif = (struct ifnet *)0;
910 char buf[4 * sizeof "123"];
911 strcpy(buf, inet_ntoa(ip->ip_dst));
912 printf("icmp_send dst %s src %s\n",
913 buf, inet_ntoa(ip->ip_src));
916 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
920 * Return milliseconds since 00:00 GMT in network format.
929 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
934 * Return the next larger or smaller MTU plateau (table from RFC 1191)
935 * given current value MTU. If DIR is less than zero, a larger plateau
936 * is returned; otherwise, a smaller value is returned.
939 ip_next_mtu(int mtu, int dir)
941 static int mtutab[] = {
942 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
947 size = (sizeof mtutab) / (sizeof mtutab[0]);
949 for (i = 0; i < size; i++)
953 for (i = size - 1; i >= 0; i--)
956 if (mtu == mtutab[0])
965 * badport_bandlim() - check for ICMP bandwidth limit
967 * Return 0 if it is ok to send an ICMP error response, -1 if we have
968 * hit our bandwidth limit and it is not ok.
970 * If icmplim is <= 0, the feature is disabled and 0 is returned.
972 * For now we separate the TCP and UDP subsystems w/ different 'which'
973 * values. We may eventually remove this separation (and simplify the
976 * Note that the printing of the error message is delayed so we can
977 * properly print the icmp error rate that the system was trying to do
978 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
979 * the 'final' error, but it doesn't make sense to solve the printing
980 * delay with more complex code.
984 badport_bandlim(int which)
987 #define N(a) (sizeof (a) / sizeof (a[0]))
990 struct timeval lasttime;
992 } rates[BANDLIM_MAX+1] = {
993 { "icmp unreach response" },
994 { "icmp ping response" },
995 { "icmp tstamp response" },
996 { "closed port RST response" },
997 { "open port RST response" },
998 { "icmp6 unreach response" },
999 { "sctp ootb response" }
1003 * Return ok status if feature disabled or argument out of range.
1005 if (V_icmplim > 0 && (u_int) which < N(rates)) {
1006 struct rate *r = &rates[which];
1007 int opps = r->curpps;
1009 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim))
1010 return -1; /* discard packet */
1012 * If we've dropped below the threshold after having
1013 * rate-limited traffic print the message. This preserves
1014 * the previous behaviour at the expense of added complexity.
1016 if (V_icmplim_output && opps > V_icmplim)
1017 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n",
1018 r->type, opps, V_icmplim);
1020 return 0; /* okay to send packet */