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>
45 #include <sys/rmlock.h>
46 #include <sys/sysctl.h>
47 #include <sys/syslog.h>
50 #include <net/if_var.h>
51 #include <net/if_types.h>
52 #include <net/route.h>
55 #include <netinet/in.h>
56 #include <netinet/in_fib.h>
57 #include <netinet/in_pcb.h>
58 #include <netinet/in_systm.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip.h>
61 #include <netinet/ip_icmp.h>
62 #include <netinet/ip_var.h>
63 #include <netinet/ip_options.h>
64 #include <netinet/tcp.h>
65 #include <netinet/tcp_var.h>
66 #include <netinet/tcpip.h>
67 #include <netinet/icmp_var.h>
71 #include <machine/in_cksum.h>
73 #include <security/mac/mac_framework.h>
77 * ICMP routines: error generation, receive packet processing, and
78 * routines to turnaround packets back to the originator, and
79 * host table maintenance routines.
81 static VNET_DEFINE(int, icmplim) = 200;
82 #define V_icmplim VNET(icmplim)
83 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_VNET | CTLFLAG_RW,
84 &VNET_NAME(icmplim), 0,
85 "Maximum number of ICMP responses per second");
87 static VNET_DEFINE(int, icmplim_output) = 1;
88 #define V_icmplim_output VNET(icmplim_output)
89 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_VNET | CTLFLAG_RW,
90 &VNET_NAME(icmplim_output), 0,
91 "Enable logging of ICMP response rate limiting");
94 VNET_PCPUSTAT_DEFINE(struct icmpstat, icmpstat);
95 VNET_PCPUSTAT_SYSINIT(icmpstat);
96 SYSCTL_VNET_PCPUSTAT(_net_inet_icmp, ICMPCTL_STATS, stats, struct icmpstat,
97 icmpstat, "ICMP statistics (struct icmpstat, netinet/icmp_var.h)");
100 VNET_PCPUSTAT_SYSUNINIT(icmpstat);
103 static VNET_DEFINE(int, icmpmaskrepl) = 0;
104 #define V_icmpmaskrepl VNET(icmpmaskrepl)
105 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_VNET | CTLFLAG_RW,
106 &VNET_NAME(icmpmaskrepl), 0,
107 "Reply to ICMP Address Mask Request packets");
109 static VNET_DEFINE(u_int, icmpmaskfake) = 0;
110 #define V_icmpmaskfake VNET(icmpmaskfake)
111 SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_VNET | CTLFLAG_RW,
112 &VNET_NAME(icmpmaskfake), 0,
113 "Fake reply to ICMP Address Mask Request packets");
115 VNET_DEFINE(int, drop_redirect) = 0;
116 #define V_drop_redirect VNET(drop_redirect)
117 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_VNET | CTLFLAG_RW,
118 &VNET_NAME(drop_redirect), 0,
119 "Ignore ICMP redirects");
121 static VNET_DEFINE(int, log_redirect) = 0;
122 #define V_log_redirect VNET(log_redirect)
123 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_VNET | CTLFLAG_RW,
124 &VNET_NAME(log_redirect), 0,
125 "Log ICMP redirects to the console");
127 static VNET_DEFINE(char, reply_src[IFNAMSIZ]);
128 #define V_reply_src VNET(reply_src)
129 SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_VNET | CTLFLAG_RW,
130 &VNET_NAME(reply_src), IFNAMSIZ,
131 "ICMP reply source for non-local packets");
133 static VNET_DEFINE(int, icmp_rfi) = 0;
134 #define V_icmp_rfi VNET(icmp_rfi)
135 SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_VNET | CTLFLAG_RW,
136 &VNET_NAME(icmp_rfi), 0,
137 "ICMP reply from incoming interface for non-local packets");
139 static VNET_DEFINE(int, icmp_quotelen) = 8;
140 #define V_icmp_quotelen VNET(icmp_quotelen)
141 SYSCTL_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_VNET | CTLFLAG_RW,
142 &VNET_NAME(icmp_quotelen), 0,
143 "Number of bytes from original packet to quote in ICMP reply");
145 static VNET_DEFINE(int, icmpbmcastecho) = 0;
146 #define V_icmpbmcastecho VNET(icmpbmcastecho)
147 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_VNET | CTLFLAG_RW,
148 &VNET_NAME(icmpbmcastecho), 0,
149 "Reply to multicast ICMP Echo Request and Timestamp packets");
151 static VNET_DEFINE(int, icmptstamprepl) = 1;
152 #define V_icmptstamprepl VNET(icmptstamprepl)
153 SYSCTL_INT(_net_inet_icmp, OID_AUTO, tstamprepl, CTLFLAG_RW,
154 &VNET_NAME(icmptstamprepl), 0,
155 "Respond to ICMP Timestamp packets");
161 static void icmp_reflect(struct mbuf *);
162 static void icmp_send(struct mbuf *, struct mbuf *);
164 extern struct protosw inetsw[];
167 * Kernel module interface for updating icmpstat. The argument is an index
168 * into icmpstat treated as an array of u_long. While this encodes the
169 * general layout of icmpstat into the caller, it doesn't encode its
170 * location, so that future changes to add, for example, per-CPU stats
171 * support won't cause binary compatibility problems for kernel modules.
174 kmod_icmpstat_inc(int statnum)
177 counter_u64_add(VNET(icmpstat)[statnum], 1);
181 * Generate an error packet of type error
182 * in response to bad packet ip.
185 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
187 register struct ip *oip = mtod(n, struct ip *), *nip;
188 register unsigned oiphlen = oip->ip_hl << 2;
189 register struct icmp *icp;
190 register struct mbuf *m;
191 unsigned icmplen, icmpelen, nlen;
193 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
196 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
198 if (type != ICMP_REDIRECT)
199 ICMPSTAT_INC(icps_error);
202 * if the original packet was encrypted.
203 * if not the first fragment of message.
204 * in response to a multicast or broadcast packet.
205 * if the old packet protocol was an ICMP error message.
207 if (n->m_flags & M_DECRYPTED)
209 if (oip->ip_off & htons(~(IP_MF|IP_DF)))
211 if (n->m_flags & (M_BCAST|M_MCAST))
213 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
214 n->m_len >= oiphlen + ICMP_MINLEN &&
215 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
216 ICMPSTAT_INC(icps_oldicmp);
219 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
220 if (oiphlen + 8 > n->m_len)
223 * Calculate length to quote from original packet and
224 * prevent the ICMP mbuf from overflowing.
225 * Unfortunately this is non-trivial since ip_forward()
226 * sends us truncated packets.
228 nlen = m_length(n, NULL);
229 if (oip->ip_p == IPPROTO_TCP) {
233 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
236 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
237 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
239 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
240 tcphlen = th->th_off << 2;
241 if (tcphlen < sizeof(struct tcphdr))
243 if (ntohs(oip->ip_len) < oiphlen + tcphlen)
245 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
247 if (n->m_len < oiphlen + tcphlen &&
248 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
250 icmpelen = max(tcphlen, min(V_icmp_quotelen,
251 ntohs(oip->ip_len) - oiphlen));
253 stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen));
255 icmplen = min(oiphlen + icmpelen, nlen);
256 if (icmplen < sizeof(struct ip))
259 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
260 m = m_gethdr(M_NOWAIT, MT_DATA);
262 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
266 mac_netinet_icmp_reply(n, m);
268 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
269 m_align(m, ICMP_MINLEN + icmplen);
270 m->m_len = ICMP_MINLEN + icmplen;
272 /* XXX MRT make the outgoing packet use the same FIB
273 * that was associated with the incoming packet
275 M_SETFIB(m, M_GETFIB(n));
276 icp = mtod(m, struct icmp *);
277 ICMPSTAT_INC(icps_outhist[type]);
278 icp->icmp_type = type;
279 if (type == ICMP_REDIRECT)
280 icp->icmp_gwaddr.s_addr = dest;
284 * The following assignments assume an overlay with the
285 * just zeroed icmp_void field.
287 if (type == ICMP_PARAMPROB) {
288 icp->icmp_pptr = code;
290 } else if (type == ICMP_UNREACH &&
291 code == ICMP_UNREACH_NEEDFRAG && mtu) {
292 icp->icmp_nextmtu = htons(mtu);
295 icp->icmp_code = code;
298 * Copy the quotation into ICMP message and
299 * convert quoted IP header back to network representation.
301 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
305 * Set up ICMP message mbuf and copy old IP header (without options
306 * in front of ICMP message.
307 * If the original mbuf was meant to bypass the firewall, the error
308 * reply should bypass as well.
310 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
311 m->m_data -= sizeof(struct ip);
312 m->m_len += sizeof(struct ip);
313 m->m_pkthdr.len = m->m_len;
314 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
315 nip = mtod(m, struct ip *);
316 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
317 nip->ip_len = htons(m->m_len);
318 nip->ip_v = IPVERSION;
320 nip->ip_p = IPPROTO_ICMP;
330 * Process a received ICMP message.
333 icmp_input(struct mbuf **mp, int *offp, int proto)
336 struct in_ifaddr *ia;
337 struct mbuf *m = *mp;
338 struct ip *ip = mtod(m, struct ip *);
339 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
341 int icmplen = ntohs(ip->ip_len) - *offp;
343 void (*ctlfunc)(int, struct sockaddr *, void *);
349 * Locate icmp structure in mbuf, and check
350 * that not corrupted and of at least minimum length.
354 char buf[4 * sizeof "123"];
355 strcpy(buf, inet_ntoa(ip->ip_src));
356 printf("icmp_input from %s to %s, len %d\n",
357 buf, inet_ntoa(ip->ip_dst), icmplen);
360 if (icmplen < ICMP_MINLEN) {
361 ICMPSTAT_INC(icps_tooshort);
364 i = hlen + min(icmplen, ICMP_ADVLENMIN);
365 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
366 ICMPSTAT_INC(icps_tooshort);
367 return (IPPROTO_DONE);
369 ip = mtod(m, struct ip *);
372 icp = mtod(m, struct icmp *);
373 if (in_cksum(m, icmplen)) {
374 ICMPSTAT_INC(icps_checksum);
382 printf("icmp_input, type %d code %d\n", icp->icmp_type,
387 * Message type specific processing.
389 if (icp->icmp_type > ICMP_MAXTYPE)
393 bzero(&icmpsrc, sizeof(icmpsrc));
394 icmpsrc.sin_len = sizeof(struct sockaddr_in);
395 icmpsrc.sin_family = AF_INET;
396 bzero(&icmpdst, sizeof(icmpdst));
397 icmpdst.sin_len = sizeof(struct sockaddr_in);
398 icmpdst.sin_family = AF_INET;
399 bzero(&icmpgw, sizeof(icmpgw));
400 icmpgw.sin_len = sizeof(struct sockaddr_in);
401 icmpgw.sin_family = AF_INET;
403 ICMPSTAT_INC(icps_inhist[icp->icmp_type]);
404 code = icp->icmp_code;
405 switch (icp->icmp_type) {
409 case ICMP_UNREACH_NET:
410 case ICMP_UNREACH_HOST:
411 case ICMP_UNREACH_SRCFAIL:
412 case ICMP_UNREACH_NET_UNKNOWN:
413 case ICMP_UNREACH_HOST_UNKNOWN:
414 case ICMP_UNREACH_ISOLATED:
415 case ICMP_UNREACH_TOSNET:
416 case ICMP_UNREACH_TOSHOST:
417 case ICMP_UNREACH_HOST_PRECEDENCE:
418 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
419 code = PRC_UNREACH_NET;
422 case ICMP_UNREACH_NEEDFRAG:
427 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
428 * Treat subcodes 2,3 as immediate RST
430 case ICMP_UNREACH_PROTOCOL:
431 case ICMP_UNREACH_PORT:
432 code = PRC_UNREACH_PORT;
435 case ICMP_UNREACH_NET_PROHIB:
436 case ICMP_UNREACH_HOST_PROHIB:
437 case ICMP_UNREACH_FILTER_PROHIB:
438 code = PRC_UNREACH_ADMIN_PROHIB;
449 code += PRC_TIMXCEED_INTRANS;
455 code = PRC_PARAMPROB;
458 * Problem with datagram; advise higher level routines.
460 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
461 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
462 ICMPSTAT_INC(icps_badlen);
465 /* Discard ICMP's in response to multicast packets */
466 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
470 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
472 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
474 * XXX if the packet contains [IPv4 AH TCP], we can't make a
475 * notification to TCP layer.
477 i = sizeof(struct ip) + min(icmplen, ICMP_ADVLENPREF(icp));
479 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
480 /* This should actually not happen */
481 ICMPSTAT_INC(icps_tooshort);
482 return (IPPROTO_DONE);
484 ip = mtod(m, struct ip *);
485 icp = (struct icmp *)(ip + 1);
487 * The upper layer handler can rely on:
488 * - The outer IP header has no options.
489 * - The outer IP header, the ICMP header, the inner IP header,
490 * and the first n bytes of the inner payload are contiguous.
491 * n is at least 8, but might be larger based on
492 * ICMP_ADVLENPREF. See its definition in ip_icmp.h.
494 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
496 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
497 (void *)&icp->icmp_ip);
501 ICMPSTAT_INC(icps_badcode);
505 if (!V_icmpbmcastecho
506 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
507 ICMPSTAT_INC(icps_bmcastecho);
510 icp->icmp_type = ICMP_ECHOREPLY;
511 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
517 if (V_icmptstamprepl == 0)
519 if (!V_icmpbmcastecho
520 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
521 ICMPSTAT_INC(icps_bmcasttstamp);
524 if (icmplen < ICMP_TSLEN) {
525 ICMPSTAT_INC(icps_badlen);
528 icp->icmp_type = ICMP_TSTAMPREPLY;
529 icp->icmp_rtime = iptime();
530 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
531 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
537 if (V_icmpmaskrepl == 0)
540 * We are not able to respond with all ones broadcast
541 * unless we receive it over a point-to-point interface.
543 if (icmplen < ICMP_MASKLEN)
545 switch (ip->ip_dst.s_addr) {
547 case INADDR_BROADCAST:
549 icmpdst.sin_addr = ip->ip_src;
553 icmpdst.sin_addr = ip->ip_dst;
555 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
556 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
559 if (ia->ia_ifp == NULL) {
560 ifa_free(&ia->ia_ifa);
563 icp->icmp_type = ICMP_MASKREPLY;
564 if (V_icmpmaskfake == 0)
565 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
567 icp->icmp_mask = V_icmpmaskfake;
568 if (ip->ip_src.s_addr == 0) {
569 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
570 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
571 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
572 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
574 ifa_free(&ia->ia_ifa);
576 ICMPSTAT_INC(icps_reflect);
577 ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
579 return (IPPROTO_DONE);
582 if (V_log_redirect) {
585 src = ntohl(ip->ip_src.s_addr);
586 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
587 gw = ntohl(icp->icmp_gwaddr.s_addr);
588 printf("icmp redirect from %d.%d.%d.%d: "
589 "%d.%d.%d.%d => %d.%d.%d.%d\n",
590 (int)(src >> 24), (int)((src >> 16) & 0xff),
591 (int)((src >> 8) & 0xff), (int)(src & 0xff),
592 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
593 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
594 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
595 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
598 * RFC1812 says we must ignore ICMP redirects if we
599 * are acting as router.
601 if (V_drop_redirect || V_ipforwarding)
605 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
606 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
607 ICMPSTAT_INC(icps_badlen);
611 * Short circuit routing redirects to force
612 * immediate change in the kernel's routing
613 * tables. The message is also handed to anyone
614 * listening on a raw socket (e.g. the routing
615 * daemon for use in updating its tables).
617 icmpgw.sin_addr = ip->ip_src;
618 icmpdst.sin_addr = icp->icmp_gwaddr;
621 char buf[4 * sizeof "123"];
622 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
624 printf("redirect dst %s to %s\n",
625 buf, inet_ntoa(icp->icmp_gwaddr));
628 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
629 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
630 in_rtredirect((struct sockaddr *)&icmpsrc,
631 (struct sockaddr *)&icmpdst,
632 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
633 (struct sockaddr *)&icmpgw, fibnum);
635 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
639 * No kernel processing for the following;
640 * just fall through to send to raw listener.
643 case ICMP_ROUTERADVERT:
644 case ICMP_ROUTERSOLICIT:
645 case ICMP_TSTAMPREPLY:
648 case ICMP_SOURCEQUENCH:
655 rip_input(mp, offp, proto);
656 return (IPPROTO_DONE);
660 return (IPPROTO_DONE);
664 * Reflect the ip packet back to the source
667 icmp_reflect(struct mbuf *m)
669 struct rm_priotracker in_ifa_tracker;
670 struct ip *ip = mtod(m, struct ip *);
673 struct in_ifaddr *ia;
675 struct nhop4_extended nh_ext;
676 struct mbuf *opts = NULL;
677 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
679 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
680 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) ||
681 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) {
682 m_freem(m); /* Bad return address */
683 ICMPSTAT_INC(icps_badaddr);
684 goto done; /* Ip_output() will check for broadcast */
688 ip->ip_dst = ip->ip_src;
691 * Source selection for ICMP replies:
693 * If the incoming packet was addressed directly to one of our
694 * own addresses, use dst as the src for the reply.
696 IN_IFADDR_RLOCK(&in_ifa_tracker);
697 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
698 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
699 t = IA_SIN(ia)->sin_addr;
700 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
704 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
707 * If the incoming packet was addressed to one of our broadcast
708 * addresses, use the first non-broadcast address which corresponds
709 * to the incoming interface.
711 ifp = m->m_pkthdr.rcvif;
712 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
714 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
715 if (ifa->ifa_addr->sa_family != AF_INET)
718 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
720 t = IA_SIN(ia)->sin_addr;
721 IF_ADDR_RUNLOCK(ifp);
725 IF_ADDR_RUNLOCK(ifp);
728 * If the packet was transiting through us, use the address of
729 * the interface the packet came through in. If that interface
730 * doesn't have a suitable IP address, the normal selection
733 if (V_icmp_rfi && ifp != NULL) {
735 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
736 if (ifa->ifa_addr->sa_family != AF_INET)
739 t = IA_SIN(ia)->sin_addr;
740 IF_ADDR_RUNLOCK(ifp);
743 IF_ADDR_RUNLOCK(ifp);
746 * If the incoming packet was not addressed directly to us, use
747 * designated interface for icmp replies specified by sysctl
748 * net.inet.icmp.reply_src (default not set). Otherwise continue
749 * with normal source selection.
751 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
753 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
754 if (ifa->ifa_addr->sa_family != AF_INET)
757 t = IA_SIN(ia)->sin_addr;
758 IF_ADDR_RUNLOCK(ifp);
761 IF_ADDR_RUNLOCK(ifp);
764 * If the packet was transiting through us, use the address of
765 * the interface that is the closest to the packet source.
766 * When we don't have a route back to the packet source, stop here
767 * and drop the packet.
769 if (fib4_lookup_nh_ext(M_GETFIB(m), ip->ip_dst, 0, 0, &nh_ext) != 0) {
771 ICMPSTAT_INC(icps_noroute);
777 mac_netinet_icmp_replyinplace(m);
780 ip->ip_ttl = V_ip_defttl;
788 * Retrieve any source routing from the incoming packet;
789 * add on any record-route or timestamp options.
791 cp = (u_char *) (ip + 1);
792 if ((opts = ip_srcroute(m)) == NULL &&
793 (opts = m_gethdr(M_NOWAIT, MT_DATA))) {
794 opts->m_len = sizeof(struct in_addr);
795 mtod(opts, struct in_addr *)->s_addr = 0;
800 printf("icmp_reflect optlen %d rt %d => ",
801 optlen, opts->m_len);
803 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
804 opt = cp[IPOPT_OPTVAL];
805 if (opt == IPOPT_EOL)
807 if (opt == IPOPT_NOP)
810 if (cnt < IPOPT_OLEN + sizeof(*cp))
812 len = cp[IPOPT_OLEN];
813 if (len < IPOPT_OLEN + sizeof(*cp) ||
818 * Should check for overflow, but it "can't happen"
820 if (opt == IPOPT_RR || opt == IPOPT_TS ||
821 opt == IPOPT_SECURITY) {
823 mtod(opts, caddr_t) + opts->m_len, len);
827 /* Terminate & pad, if necessary */
828 cnt = opts->m_len % 4;
830 for (; cnt < 4; cnt++) {
831 *(mtod(opts, caddr_t) + opts->m_len) =
838 printf("%d\n", opts->m_len);
843 m_tag_delete_nonpersistent(m);
844 m->m_flags &= ~(M_BCAST|M_MCAST);
852 * Send an icmp packet back to the ip level,
853 * after supplying a checksum.
856 icmp_send(struct mbuf *m, struct mbuf *opts)
858 register struct ip *ip = mtod(m, struct ip *);
860 register struct icmp *icp;
862 hlen = ip->ip_hl << 2;
865 icp = mtod(m, struct icmp *);
867 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
870 m->m_pkthdr.rcvif = (struct ifnet *)0;
873 char buf[4 * sizeof "123"];
874 strcpy(buf, inet_ntoa(ip->ip_dst));
875 printf("icmp_send dst %s src %s\n",
876 buf, inet_ntoa(ip->ip_src));
879 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
883 * Return milliseconds since 00:00 UTC in network format.
892 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
897 * Return the next larger or smaller MTU plateau (table from RFC 1191)
898 * given current value MTU. If DIR is less than zero, a larger plateau
899 * is returned; otherwise, a smaller value is returned.
902 ip_next_mtu(int mtu, int dir)
904 static int mtutab[] = {
905 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
910 size = (sizeof mtutab) / (sizeof mtutab[0]);
912 for (i = 0; i < size; i++)
916 for (i = size - 1; i >= 0; i--)
919 if (mtu == mtutab[0])
928 * badport_bandlim() - check for ICMP bandwidth limit
930 * Return 0 if it is ok to send an ICMP error response, -1 if we have
931 * hit our bandwidth limit and it is not ok.
933 * If icmplim is <= 0, the feature is disabled and 0 is returned.
935 * For now we separate the TCP and UDP subsystems w/ different 'which'
936 * values. We may eventually remove this separation (and simplify the
939 * Note that the printing of the error message is delayed so we can
940 * properly print the icmp error rate that the system was trying to do
941 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
942 * the 'final' error, but it doesn't make sense to solve the printing
943 * delay with more complex code.
947 badport_bandlim(int which)
950 #define N(a) (sizeof (a) / sizeof (a[0]))
953 struct timeval lasttime;
955 } rates[BANDLIM_MAX+1] = {
956 { "icmp unreach response" },
957 { "icmp ping response" },
958 { "icmp tstamp response" },
959 { "closed port RST response" },
960 { "open port RST response" },
961 { "icmp6 unreach response" },
962 { "sctp ootb response" }
966 * Return ok status if feature disabled or argument out of range.
968 if (V_icmplim > 0 && (u_int) which < N(rates)) {
969 struct rate *r = &rates[which];
970 int opps = r->curpps;
972 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim))
973 return -1; /* discard packet */
975 * If we've dropped below the threshold after having
976 * rate-limited traffic print the message. This preserves
977 * the previous behaviour at the expense of added complexity.
979 if (V_icmplim_output && opps > V_icmplim)
980 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n",
981 r->type, opps, V_icmplim);
983 return 0; /* okay to send packet */