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
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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
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19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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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/sctp.h>
65 #include <netinet/tcp.h>
66 #include <netinet/tcp_var.h>
67 #include <netinet/tcpip.h>
68 #include <netinet/icmp_var.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_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_VNET | 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_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_VNET | CTLFLAG_RW,
91 &VNET_NAME(icmplim_output), 0,
92 "Enable logging of ICMP response rate limiting");
95 VNET_PCPUSTAT_DEFINE(struct icmpstat, icmpstat);
96 VNET_PCPUSTAT_SYSINIT(icmpstat);
97 SYSCTL_VNET_PCPUSTAT(_net_inet_icmp, ICMPCTL_STATS, stats, struct icmpstat,
98 icmpstat, "ICMP statistics (struct icmpstat, netinet/icmp_var.h)");
101 VNET_PCPUSTAT_SYSUNINIT(icmpstat);
104 static VNET_DEFINE(int, icmpmaskrepl) = 0;
105 #define V_icmpmaskrepl VNET(icmpmaskrepl)
106 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_VNET | CTLFLAG_RW,
107 &VNET_NAME(icmpmaskrepl), 0,
108 "Reply to ICMP Address Mask Request packets");
110 static VNET_DEFINE(u_int, icmpmaskfake) = 0;
111 #define V_icmpmaskfake VNET(icmpmaskfake)
112 SYSCTL_UINT(_net_inet_icmp, OID_AUTO, maskfake, CTLFLAG_VNET | CTLFLAG_RW,
113 &VNET_NAME(icmpmaskfake), 0,
114 "Fake reply to ICMP Address Mask Request packets");
116 VNET_DEFINE(int, drop_redirect) = 0;
117 #define V_drop_redirect VNET(drop_redirect)
118 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_VNET | CTLFLAG_RW,
119 &VNET_NAME(drop_redirect), 0,
120 "Ignore ICMP redirects");
122 static VNET_DEFINE(int, log_redirect) = 0;
123 #define V_log_redirect VNET(log_redirect)
124 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_VNET | CTLFLAG_RW,
125 &VNET_NAME(log_redirect), 0,
126 "Log ICMP redirects to the console");
128 static VNET_DEFINE(char, reply_src[IFNAMSIZ]);
129 #define V_reply_src VNET(reply_src)
130 SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_VNET | CTLFLAG_RW,
131 &VNET_NAME(reply_src), IFNAMSIZ,
132 "ICMP reply source for non-local packets");
134 static VNET_DEFINE(int, icmp_rfi) = 0;
135 #define V_icmp_rfi VNET(icmp_rfi)
136 SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_VNET | CTLFLAG_RW,
137 &VNET_NAME(icmp_rfi), 0,
138 "ICMP reply from incoming interface for non-local packets");
140 static VNET_DEFINE(int, icmp_quotelen) = 8;
141 #define V_icmp_quotelen VNET(icmp_quotelen)
142 SYSCTL_INT(_net_inet_icmp, OID_AUTO, quotelen, CTLFLAG_VNET | CTLFLAG_RW,
143 &VNET_NAME(icmp_quotelen), 0,
144 "Number of bytes from original packet to quote in ICMP reply");
146 static VNET_DEFINE(int, icmpbmcastecho) = 0;
147 #define V_icmpbmcastecho VNET(icmpbmcastecho)
148 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_VNET | CTLFLAG_RW,
149 &VNET_NAME(icmpbmcastecho), 0,
150 "Reply to multicast ICMP Echo Request and Timestamp packets");
152 static VNET_DEFINE(int, icmptstamprepl) = 1;
153 #define V_icmptstamprepl VNET(icmptstamprepl)
154 SYSCTL_INT(_net_inet_icmp, OID_AUTO, tstamprepl, CTLFLAG_RW,
155 &VNET_NAME(icmptstamprepl), 0,
156 "Respond to ICMP Timestamp packets");
162 static void icmp_reflect(struct mbuf *);
163 static void icmp_send(struct mbuf *, struct mbuf *);
165 extern struct protosw inetsw[];
168 * Kernel module interface for updating icmpstat. The argument is an index
169 * into icmpstat treated as an array of u_long. While this encodes the
170 * general layout of icmpstat into the caller, it doesn't encode its
171 * location, so that future changes to add, for example, per-CPU stats
172 * support won't cause binary compatibility problems for kernel modules.
175 kmod_icmpstat_inc(int statnum)
178 counter_u64_add(VNET(icmpstat)[statnum], 1);
182 * Generate an error packet of type error
183 * in response to bad packet ip.
186 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
188 register struct ip *oip = mtod(n, struct ip *), *nip;
189 register unsigned oiphlen = oip->ip_hl << 2;
190 register struct icmp *icp;
191 register struct mbuf *m;
192 unsigned icmplen, icmpelen, nlen;
194 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
197 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
199 if (type != ICMP_REDIRECT)
200 ICMPSTAT_INC(icps_error);
203 * if the original packet was encrypted.
204 * if not the first fragment of message.
205 * in response to a multicast or broadcast packet.
206 * if the old packet protocol was an ICMP error message.
208 if (n->m_flags & M_DECRYPTED)
210 if (oip->ip_off & htons(~(IP_MF|IP_DF)))
212 if (n->m_flags & (M_BCAST|M_MCAST))
214 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
215 n->m_len >= oiphlen + ICMP_MINLEN &&
216 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
217 ICMPSTAT_INC(icps_oldicmp);
220 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
221 if (oiphlen + 8 > n->m_len)
224 * Calculate length to quote from original packet and
225 * prevent the ICMP mbuf from overflowing.
226 * Unfortunately this is non-trivial since ip_forward()
227 * sends us truncated packets.
229 nlen = m_length(n, NULL);
230 if (oip->ip_p == IPPROTO_TCP) {
234 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
237 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
238 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
240 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
241 tcphlen = th->th_off << 2;
242 if (tcphlen < sizeof(struct tcphdr))
244 if (ntohs(oip->ip_len) < oiphlen + tcphlen)
246 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
248 if (n->m_len < oiphlen + tcphlen &&
249 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
251 icmpelen = max(tcphlen, min(V_icmp_quotelen,
252 ntohs(oip->ip_len) - oiphlen));
253 } else if (oip->ip_p == IPPROTO_SCTP) {
255 struct sctp_chunkhdr *ch;
257 if (ntohs(oip->ip_len) < oiphlen + sizeof(struct sctphdr))
259 if (oiphlen + sizeof(struct sctphdr) > n->m_len &&
262 if (n->m_len < oiphlen + sizeof(struct sctphdr) &&
263 (n = m_pullup(n, oiphlen + sizeof(struct sctphdr))) == NULL)
265 icmpelen = max(sizeof(struct sctphdr),
266 min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen));
267 sh = (struct sctphdr *)((caddr_t)oip + oiphlen);
268 if (ntohl(sh->v_tag) == 0 &&
269 ntohs(oip->ip_len) >= oiphlen + sizeof(struct sctphdr) + 8 &&
270 (n->m_len >= oiphlen + sizeof(struct sctphdr) + 8 ||
271 n->m_next != NULL)) {
272 if (n->m_len < oiphlen + sizeof(struct sctphdr) + 8 &&
273 (n = m_pullup(n, oiphlen + sizeof(struct sctphdr) + 8)) == NULL)
275 ch = (struct sctp_chunkhdr *)(sh + 1);
276 if (ch->chunk_type == SCTP_INITIATION) {
277 icmpelen = max(sizeof(struct sctphdr) + 8,
278 min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen));
282 stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen));
284 icmplen = min(oiphlen + icmpelen, nlen);
285 if (icmplen < sizeof(struct ip))
288 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
289 m = m_gethdr(M_NOWAIT, MT_DATA);
291 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
295 mac_netinet_icmp_reply(n, m);
297 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
298 m_align(m, ICMP_MINLEN + icmplen);
299 m->m_len = ICMP_MINLEN + icmplen;
301 /* XXX MRT make the outgoing packet use the same FIB
302 * that was associated with the incoming packet
304 M_SETFIB(m, M_GETFIB(n));
305 icp = mtod(m, struct icmp *);
306 ICMPSTAT_INC(icps_outhist[type]);
307 icp->icmp_type = type;
308 if (type == ICMP_REDIRECT)
309 icp->icmp_gwaddr.s_addr = dest;
313 * The following assignments assume an overlay with the
314 * just zeroed icmp_void field.
316 if (type == ICMP_PARAMPROB) {
317 icp->icmp_pptr = code;
319 } else if (type == ICMP_UNREACH &&
320 code == ICMP_UNREACH_NEEDFRAG && mtu) {
321 icp->icmp_nextmtu = htons(mtu);
324 icp->icmp_code = code;
327 * Copy the quotation into ICMP message and
328 * convert quoted IP header back to network representation.
330 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
334 * Set up ICMP message mbuf and copy old IP header (without options
335 * in front of ICMP message.
336 * If the original mbuf was meant to bypass the firewall, the error
337 * reply should bypass as well.
339 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
340 m->m_data -= sizeof(struct ip);
341 m->m_len += sizeof(struct ip);
342 m->m_pkthdr.len = m->m_len;
343 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
344 nip = mtod(m, struct ip *);
345 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
346 nip->ip_len = htons(m->m_len);
347 nip->ip_v = IPVERSION;
349 nip->ip_p = IPPROTO_ICMP;
359 * Process a received ICMP message.
362 icmp_input(struct mbuf **mp, int *offp, int proto)
365 struct in_ifaddr *ia;
366 struct mbuf *m = *mp;
367 struct ip *ip = mtod(m, struct ip *);
368 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
370 int icmplen = ntohs(ip->ip_len) - *offp;
372 void (*ctlfunc)(int, struct sockaddr *, void *);
378 * Locate icmp structure in mbuf, and check
379 * that not corrupted and of at least minimum length.
383 char buf[4 * sizeof "123"];
384 strcpy(buf, inet_ntoa(ip->ip_src));
385 printf("icmp_input from %s to %s, len %d\n",
386 buf, inet_ntoa(ip->ip_dst), icmplen);
389 if (icmplen < ICMP_MINLEN) {
390 ICMPSTAT_INC(icps_tooshort);
393 i = hlen + min(icmplen, ICMP_ADVLENMIN);
394 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
395 ICMPSTAT_INC(icps_tooshort);
396 return (IPPROTO_DONE);
398 ip = mtod(m, struct ip *);
401 icp = mtod(m, struct icmp *);
402 if (in_cksum(m, icmplen)) {
403 ICMPSTAT_INC(icps_checksum);
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 code = PRC_UNREACH_PROTOCOL;
462 case ICMP_UNREACH_PORT:
463 code = PRC_UNREACH_PORT;
466 case ICMP_UNREACH_NET_PROHIB:
467 case ICMP_UNREACH_HOST_PROHIB:
468 case ICMP_UNREACH_FILTER_PROHIB:
469 code = PRC_UNREACH_ADMIN_PROHIB;
480 code += PRC_TIMXCEED_INTRANS;
486 code = PRC_PARAMPROB;
489 * Problem with datagram; advise higher level routines.
491 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
492 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
493 ICMPSTAT_INC(icps_badlen);
496 /* Discard ICMP's in response to multicast packets */
497 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
501 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
503 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
505 * XXX if the packet contains [IPv4 AH TCP], we can't make a
506 * notification to TCP layer.
508 i = sizeof(struct ip) + min(icmplen, ICMP_ADVLENPREF(icp));
510 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
511 /* This should actually not happen */
512 ICMPSTAT_INC(icps_tooshort);
513 return (IPPROTO_DONE);
515 ip = mtod(m, struct ip *);
516 icp = (struct icmp *)(ip + 1);
518 * The upper layer handler can rely on:
519 * - The outer IP header has no options.
520 * - The outer IP header, the ICMP header, the inner IP header,
521 * and the first n bytes of the inner payload are contiguous.
522 * n is at least 8, but might be larger based on
523 * ICMP_ADVLENPREF. See its definition in ip_icmp.h.
525 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
527 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
528 (void *)&icp->icmp_ip);
532 ICMPSTAT_INC(icps_badcode);
536 if (!V_icmpbmcastecho
537 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
538 ICMPSTAT_INC(icps_bmcastecho);
541 icp->icmp_type = ICMP_ECHOREPLY;
542 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
548 if (V_icmptstamprepl == 0)
550 if (!V_icmpbmcastecho
551 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
552 ICMPSTAT_INC(icps_bmcasttstamp);
555 if (icmplen < ICMP_TSLEN) {
556 ICMPSTAT_INC(icps_badlen);
559 icp->icmp_type = ICMP_TSTAMPREPLY;
560 icp->icmp_rtime = iptime();
561 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
562 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
568 if (V_icmpmaskrepl == 0)
571 * We are not able to respond with all ones broadcast
572 * unless we receive it over a point-to-point interface.
574 if (icmplen < ICMP_MASKLEN)
576 switch (ip->ip_dst.s_addr) {
578 case INADDR_BROADCAST:
580 icmpdst.sin_addr = ip->ip_src;
584 icmpdst.sin_addr = ip->ip_dst;
586 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
587 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
590 if (ia->ia_ifp == NULL) {
591 ifa_free(&ia->ia_ifa);
594 icp->icmp_type = ICMP_MASKREPLY;
595 if (V_icmpmaskfake == 0)
596 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
598 icp->icmp_mask = V_icmpmaskfake;
599 if (ip->ip_src.s_addr == 0) {
600 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
601 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
602 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
603 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
605 ifa_free(&ia->ia_ifa);
607 ICMPSTAT_INC(icps_reflect);
608 ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
610 return (IPPROTO_DONE);
613 if (V_log_redirect) {
616 src = ntohl(ip->ip_src.s_addr);
617 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
618 gw = ntohl(icp->icmp_gwaddr.s_addr);
619 printf("icmp redirect from %d.%d.%d.%d: "
620 "%d.%d.%d.%d => %d.%d.%d.%d\n",
621 (int)(src >> 24), (int)((src >> 16) & 0xff),
622 (int)((src >> 8) & 0xff), (int)(src & 0xff),
623 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
624 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
625 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
626 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
629 * RFC1812 says we must ignore ICMP redirects if we
630 * are acting as router.
632 if (V_drop_redirect || V_ipforwarding)
636 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
637 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
638 ICMPSTAT_INC(icps_badlen);
642 * Short circuit routing redirects to force
643 * immediate change in the kernel's routing
644 * tables. The message is also handed to anyone
645 * listening on a raw socket (e.g. the routing
646 * daemon for use in updating its tables).
648 icmpgw.sin_addr = ip->ip_src;
649 icmpdst.sin_addr = icp->icmp_gwaddr;
652 char buf[4 * sizeof "123"];
653 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
655 printf("redirect dst %s to %s\n",
656 buf, inet_ntoa(icp->icmp_gwaddr));
659 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
660 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
661 in_rtredirect((struct sockaddr *)&icmpsrc,
662 (struct sockaddr *)&icmpdst,
663 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
664 (struct sockaddr *)&icmpgw, fibnum);
666 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
670 * No kernel processing for the following;
671 * just fall through to send to raw listener.
674 case ICMP_ROUTERADVERT:
675 case ICMP_ROUTERSOLICIT:
676 case ICMP_TSTAMPREPLY:
679 case ICMP_SOURCEQUENCH:
686 rip_input(mp, offp, proto);
687 return (IPPROTO_DONE);
691 return (IPPROTO_DONE);
695 * Reflect the ip packet back to the source
698 icmp_reflect(struct mbuf *m)
700 struct rm_priotracker in_ifa_tracker;
701 struct ip *ip = mtod(m, struct ip *);
704 struct in_ifaddr *ia;
706 struct nhop4_extended nh_ext;
707 struct mbuf *opts = NULL;
708 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
710 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
711 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) ||
712 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) {
713 m_freem(m); /* Bad return address */
714 ICMPSTAT_INC(icps_badaddr);
715 goto done; /* Ip_output() will check for broadcast */
719 ip->ip_dst = ip->ip_src;
722 * Source selection for ICMP replies:
724 * If the incoming packet was addressed directly to one of our
725 * own addresses, use dst as the src for the reply.
727 IN_IFADDR_RLOCK(&in_ifa_tracker);
728 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
729 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
730 t = IA_SIN(ia)->sin_addr;
731 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
735 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
738 * If the incoming packet was addressed to one of our broadcast
739 * addresses, use the first non-broadcast address which corresponds
740 * to the incoming interface.
742 ifp = m->m_pkthdr.rcvif;
743 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
745 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
746 if (ifa->ifa_addr->sa_family != AF_INET)
749 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
751 t = IA_SIN(ia)->sin_addr;
752 IF_ADDR_RUNLOCK(ifp);
756 IF_ADDR_RUNLOCK(ifp);
759 * If the packet was transiting through us, use the address of
760 * the interface the packet came through in. If that interface
761 * doesn't have a suitable IP address, the normal selection
764 if (V_icmp_rfi && ifp != NULL) {
766 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
767 if (ifa->ifa_addr->sa_family != AF_INET)
770 t = IA_SIN(ia)->sin_addr;
771 IF_ADDR_RUNLOCK(ifp);
774 IF_ADDR_RUNLOCK(ifp);
777 * If the incoming packet was not addressed directly to us, use
778 * designated interface for icmp replies specified by sysctl
779 * net.inet.icmp.reply_src (default not set). Otherwise continue
780 * with normal source selection.
782 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
784 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
785 if (ifa->ifa_addr->sa_family != AF_INET)
788 t = IA_SIN(ia)->sin_addr;
789 IF_ADDR_RUNLOCK(ifp);
792 IF_ADDR_RUNLOCK(ifp);
795 * If the packet was transiting through us, use the address of
796 * the interface that is the closest to the packet source.
797 * When we don't have a route back to the packet source, stop here
798 * and drop the packet.
800 if (fib4_lookup_nh_ext(M_GETFIB(m), ip->ip_dst, 0, 0, &nh_ext) != 0) {
802 ICMPSTAT_INC(icps_noroute);
808 mac_netinet_icmp_replyinplace(m);
811 ip->ip_ttl = V_ip_defttl;
819 * Retrieve any source routing from the incoming packet;
820 * add on any record-route or timestamp options.
822 cp = (u_char *) (ip + 1);
823 if ((opts = ip_srcroute(m)) == NULL &&
824 (opts = m_gethdr(M_NOWAIT, MT_DATA))) {
825 opts->m_len = sizeof(struct in_addr);
826 mtod(opts, struct in_addr *)->s_addr = 0;
831 printf("icmp_reflect optlen %d rt %d => ",
832 optlen, opts->m_len);
834 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
835 opt = cp[IPOPT_OPTVAL];
836 if (opt == IPOPT_EOL)
838 if (opt == IPOPT_NOP)
841 if (cnt < IPOPT_OLEN + sizeof(*cp))
843 len = cp[IPOPT_OLEN];
844 if (len < IPOPT_OLEN + sizeof(*cp) ||
849 * Should check for overflow, but it "can't happen"
851 if (opt == IPOPT_RR || opt == IPOPT_TS ||
852 opt == IPOPT_SECURITY) {
854 mtod(opts, caddr_t) + opts->m_len, len);
858 /* Terminate & pad, if necessary */
859 cnt = opts->m_len % 4;
861 for (; cnt < 4; cnt++) {
862 *(mtod(opts, caddr_t) + opts->m_len) =
869 printf("%d\n", opts->m_len);
874 m_tag_delete_nonpersistent(m);
875 m->m_flags &= ~(M_BCAST|M_MCAST);
883 * Send an icmp packet back to the ip level,
884 * after supplying a checksum.
887 icmp_send(struct mbuf *m, struct mbuf *opts)
889 register struct ip *ip = mtod(m, struct ip *);
891 register struct icmp *icp;
893 hlen = ip->ip_hl << 2;
896 icp = mtod(m, struct icmp *);
898 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
901 m->m_pkthdr.rcvif = (struct ifnet *)0;
904 char buf[4 * sizeof "123"];
905 strcpy(buf, inet_ntoa(ip->ip_dst));
906 printf("icmp_send dst %s src %s\n",
907 buf, inet_ntoa(ip->ip_src));
910 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
914 * Return milliseconds since 00:00 UTC in network format.
923 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
928 * Return the next larger or smaller MTU plateau (table from RFC 1191)
929 * given current value MTU. If DIR is less than zero, a larger plateau
930 * is returned; otherwise, a smaller value is returned.
933 ip_next_mtu(int mtu, int dir)
935 static int mtutab[] = {
936 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
941 size = (sizeof mtutab) / (sizeof mtutab[0]);
943 for (i = 0; i < size; i++)
947 for (i = size - 1; i >= 0; i--)
950 if (mtu == mtutab[0])
959 * badport_bandlim() - check for ICMP bandwidth limit
961 * Return 0 if it is ok to send an ICMP error response, -1 if we have
962 * hit our bandwidth limit and it is not ok.
964 * If icmplim is <= 0, the feature is disabled and 0 is returned.
966 * For now we separate the TCP and UDP subsystems w/ different 'which'
967 * values. We may eventually remove this separation (and simplify the
970 * Note that the printing of the error message is delayed so we can
971 * properly print the icmp error rate that the system was trying to do
972 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
973 * the 'final' error, but it doesn't make sense to solve the printing
974 * delay with more complex code.
978 badport_bandlim(int which)
981 #define N(a) (sizeof (a) / sizeof (a[0]))
984 struct timeval lasttime;
986 } rates[BANDLIM_MAX+1] = {
987 { "icmp unreach response" },
988 { "icmp ping response" },
989 { "icmp tstamp response" },
990 { "closed port RST response" },
991 { "open port RST response" },
992 { "icmp6 unreach response" },
993 { "sctp ootb response" }
997 * Return ok status if feature disabled or argument out of range.
999 if (V_icmplim > 0 && (u_int) which < N(rates)) {
1000 struct rate *r = &rates[which];
1001 int opps = r->curpps;
1003 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim))
1004 return -1; /* discard packet */
1006 * If we've dropped below the threshold after having
1007 * rate-limited traffic print the message. This preserves
1008 * the previous behaviour at the expense of added complexity.
1010 if (V_icmplim_output && opps > V_icmplim)
1011 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n",
1012 r->type, opps, V_icmplim);
1014 return 0; /* okay to send packet */