2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
37 #include <sys/param.h>
38 #include <sys/systm.h>
40 #include <sys/protosw.h>
41 #include <sys/socket.h>
43 #include <sys/kernel.h>
44 #include <sys/sysctl.h>
45 #include <sys/syslog.h>
48 #include <net/if_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>
67 #include <machine/in_cksum.h>
69 #include <security/mac/mac_framework.h>
73 * ICMP routines: error generation, receive packet processing, and
74 * routines to turnaround packets back to the originator, and
75 * host table maintenance routines.
77 static VNET_DEFINE(int, icmplim) = 200;
78 #define V_icmplim VNET(icmplim)
79 SYSCTL_VNET_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
80 &VNET_NAME(icmplim), 0,
81 "Maximum number of ICMP responses per second");
83 static VNET_DEFINE(int, icmplim_output) = 1;
84 #define V_icmplim_output VNET(icmplim_output)
85 SYSCTL_VNET_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
86 &VNET_NAME(icmplim_output), 0,
87 "Enable logging of ICMP response rate limiting");
90 VNET_PCPUSTAT_DEFINE(struct icmpstat, icmpstat);
91 VNET_PCPUSTAT_SYSINIT(icmpstat);
92 SYSCTL_VNET_PCPUSTAT(_net_inet_icmp, ICMPCTL_STATS, stats, struct icmpstat,
93 icmpstat, "ICMP statistics (struct icmpstat, netinet/icmp_var.h)");
96 VNET_PCPUSTAT_SYSUNINIT(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,
146 static VNET_DEFINE(int, icmptstamprepl) = 1;
147 #define V_icmptstamprepl VNET(icmptstamprepl)
148 SYSCTL_INT(_net_inet_icmp, OID_AUTO, tstamprepl, CTLFLAG_RW,
149 &VNET_NAME(icmptstamprepl), 0, "Respond to ICMP Timestamp packets");
151 static VNET_DEFINE(int, error_keeptags) = 0;
152 #define V_error_keeptags VNET(error_keeptags)
153 SYSCTL_INT(_net_inet_icmp, OID_AUTO, error_keeptags, CTLFLAG_VNET | CTLFLAG_RW,
154 &VNET_NAME(error_keeptags), 0,
155 "ICMP error response keeps copy of mbuf_tags of original packet");
161 static void icmp_reflect(struct mbuf *);
162 static void icmp_send(struct mbuf *, struct mbuf *);
164 extern struct protosw inetsw[];
167 sysctl_net_icmp_drop_redir(SYSCTL_HANDLER_ARGS)
171 struct radix_node_head *rnh;
173 new = V_drop_redirect;
174 error = sysctl_handle_int(oidp, &new, 0, req);
175 if (error == 0 && req->newptr) {
176 new = (new != 0) ? 1 : 0;
178 if (new == V_drop_redirect)
181 for (i = 0; i < rt_numfibs; i++) {
182 if ((rnh = rt_tables_get_rnh(i, AF_INET)) == NULL)
184 RADIX_NODE_HEAD_LOCK(rnh);
185 in_setmatchfunc(rnh, new);
186 RADIX_NODE_HEAD_UNLOCK(rnh);
189 V_drop_redirect = new;
195 SYSCTL_VNET_PROC(_net_inet_icmp, OID_AUTO, drop_redirect,
196 CTLTYPE_INT|CTLFLAG_RW, 0, 0,
197 sysctl_net_icmp_drop_redir, "I", "Ignore ICMP redirects");
200 * Kernel module interface for updating icmpstat. The argument is an index
201 * into icmpstat treated as an array of u_long. While this encodes the
202 * general layout of icmpstat into the caller, it doesn't encode its
203 * location, so that future changes to add, for example, per-CPU stats
204 * support won't cause binary compatibility problems for kernel modules.
207 kmod_icmpstat_inc(int statnum)
210 counter_u64_add(VNET(icmpstat)[statnum], 1);
214 * Generate an error packet of type error
215 * in response to bad packet ip.
218 icmp_error(struct mbuf *n, int type, int code, uint32_t dest, int mtu)
220 register struct ip *oip = mtod(n, struct ip *), *nip;
221 register unsigned oiphlen = oip->ip_hl << 2;
222 register struct icmp *icp;
223 register struct mbuf *m;
224 unsigned icmplen, icmpelen, nlen;
226 KASSERT((u_int)type <= ICMP_MAXTYPE, ("%s: illegal ICMP type", __func__));
229 printf("icmp_error(%p, %x, %d)\n", oip, type, code);
231 if (type != ICMP_REDIRECT)
232 ICMPSTAT_INC(icps_error);
235 * if the original packet was encrypted.
236 * if not the first fragment of message.
237 * in response to a multicast or broadcast packet.
238 * if the old packet protocol was an ICMP error message.
240 if (n->m_flags & M_DECRYPTED)
242 if (oip->ip_off & htons(~(IP_MF|IP_DF)))
244 if (n->m_flags & (M_BCAST|M_MCAST))
246 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
247 n->m_len >= oiphlen + ICMP_MINLEN &&
248 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiphlen))->icmp_type)) {
249 ICMPSTAT_INC(icps_oldicmp);
252 /* Drop if IP header plus 8 bytes is not contignous in first mbuf. */
253 if (oiphlen + 8 > n->m_len)
256 * Calculate length to quote from original packet and
257 * prevent the ICMP mbuf from overflowing.
258 * Unfortunatly this is non-trivial since ip_forward()
259 * sends us truncated packets.
261 nlen = m_length(n, NULL);
262 if (oip->ip_p == IPPROTO_TCP) {
266 if (oiphlen + sizeof(struct tcphdr) > n->m_len &&
269 if (n->m_len < oiphlen + sizeof(struct tcphdr) &&
270 ((n = m_pullup(n, oiphlen + sizeof(struct tcphdr))) == NULL))
272 th = (struct tcphdr *)((caddr_t)oip + oiphlen);
273 tcphlen = th->th_off << 2;
274 if (tcphlen < sizeof(struct tcphdr))
276 if (ntohs(oip->ip_len) < oiphlen + tcphlen)
278 if (oiphlen + tcphlen > n->m_len && n->m_next == NULL)
280 if (n->m_len < oiphlen + tcphlen &&
281 ((n = m_pullup(n, oiphlen + tcphlen)) == NULL))
283 icmpelen = max(tcphlen, min(V_icmp_quotelen,
284 ntohs(oip->ip_len) - oiphlen));
286 stdreply: icmpelen = max(8, min(V_icmp_quotelen, ntohs(oip->ip_len) - oiphlen));
288 icmplen = min(oiphlen + icmpelen, nlen);
289 if (icmplen < sizeof(struct ip))
292 if (MHLEN > sizeof(struct ip) + ICMP_MINLEN + icmplen)
293 m = m_gethdr(M_NOWAIT, MT_DATA);
295 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
299 mac_netinet_icmp_reply(n, m);
301 icmplen = min(icmplen, M_TRAILINGSPACE(m) - sizeof(struct ip) - ICMP_MINLEN);
302 m_align(m, sizeof(struct ip) + ICMP_MINLEN + icmplen);
303 m->m_data += sizeof(struct ip);
304 m->m_len = ICMP_MINLEN + icmplen;
306 /* XXX MRT make the outgoing packet use the same FIB
307 * that was associated with the incoming packet
309 M_SETFIB(m, M_GETFIB(n));
310 icp = mtod(m, struct icmp *);
311 ICMPSTAT_INC(icps_outhist[type]);
312 icp->icmp_type = type;
313 if (type == ICMP_REDIRECT)
314 icp->icmp_gwaddr.s_addr = dest;
318 * The following assignments assume an overlay with the
319 * just zeroed icmp_void field.
321 if (type == ICMP_PARAMPROB) {
322 icp->icmp_pptr = code;
324 } else if (type == ICMP_UNREACH &&
325 code == ICMP_UNREACH_NEEDFRAG && mtu) {
326 icp->icmp_nextmtu = htons(mtu);
329 icp->icmp_code = code;
332 * Copy the quotation into ICMP message and
333 * convert quoted IP header back to network representation.
335 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
339 * Set up ICMP message mbuf and copy old IP header (without options
340 * in front of ICMP message.
341 * If the original mbuf was meant to bypass the firewall, the error
342 * reply should bypass as well.
344 m->m_flags |= n->m_flags & M_SKIP_FIREWALL;
345 KASSERT(M_LEADINGSPACE(m) >= sizeof(struct ip),
346 ("insufficient space for ip header"));
347 m->m_data -= sizeof(struct ip);
348 m->m_len += sizeof(struct ip);
349 m->m_pkthdr.len = m->m_len;
350 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
351 nip = mtod(m, struct ip *);
352 bcopy((caddr_t)oip, (caddr_t)nip, sizeof(struct ip));
353 nip->ip_len = htons(m->m_len);
354 nip->ip_v = IPVERSION;
356 nip->ip_p = IPPROTO_ICMP;
360 if (V_error_keeptags)
361 m_tag_copy_chain(m, n, M_NOWAIT);
370 * Process a received ICMP message.
373 icmp_input(struct mbuf *m, int off)
376 struct in_ifaddr *ia;
377 struct ip *ip = mtod(m, struct ip *);
378 struct sockaddr_in icmpsrc, icmpdst, icmpgw;
380 int icmplen = ntohs(ip->ip_len) - off;
382 void (*ctlfunc)(int, struct sockaddr *, void *);
386 * Locate icmp structure in mbuf, and check
387 * that not corrupted and of at least minimum length.
391 char buf[4 * sizeof "123"];
392 strcpy(buf, inet_ntoa(ip->ip_src));
393 printf("icmp_input from %s to %s, len %d\n",
394 buf, inet_ntoa(ip->ip_dst), icmplen);
397 if (icmplen < ICMP_MINLEN) {
398 ICMPSTAT_INC(icps_tooshort);
401 i = hlen + min(icmplen, ICMP_ADVLENMIN);
402 if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
403 ICMPSTAT_INC(icps_tooshort);
406 ip = mtod(m, struct ip *);
409 icp = mtod(m, struct icmp *);
410 if (in_cksum(m, icmplen)) {
411 ICMPSTAT_INC(icps_checksum);
417 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
419 * Deliver very specific ICMP type only.
421 switch (icp->icmp_type) {
432 printf("icmp_input, type %d code %d\n", icp->icmp_type,
437 * Message type specific processing.
439 if (icp->icmp_type > ICMP_MAXTYPE)
443 bzero(&icmpsrc, sizeof(icmpsrc));
444 icmpsrc.sin_len = sizeof(struct sockaddr_in);
445 icmpsrc.sin_family = AF_INET;
446 bzero(&icmpdst, sizeof(icmpdst));
447 icmpdst.sin_len = sizeof(struct sockaddr_in);
448 icmpdst.sin_family = AF_INET;
449 bzero(&icmpgw, sizeof(icmpgw));
450 icmpgw.sin_len = sizeof(struct sockaddr_in);
451 icmpgw.sin_family = AF_INET;
453 ICMPSTAT_INC(icps_inhist[icp->icmp_type]);
454 code = icp->icmp_code;
455 switch (icp->icmp_type) {
459 case ICMP_UNREACH_NET:
460 case ICMP_UNREACH_HOST:
461 case ICMP_UNREACH_SRCFAIL:
462 case ICMP_UNREACH_NET_UNKNOWN:
463 case ICMP_UNREACH_HOST_UNKNOWN:
464 case ICMP_UNREACH_ISOLATED:
465 case ICMP_UNREACH_TOSNET:
466 case ICMP_UNREACH_TOSHOST:
467 case ICMP_UNREACH_HOST_PRECEDENCE:
468 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
469 code = PRC_UNREACH_NET;
472 case ICMP_UNREACH_NEEDFRAG:
477 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
478 * Treat subcodes 2,3 as immediate RST
480 case ICMP_UNREACH_PROTOCOL:
481 case ICMP_UNREACH_PORT:
482 code = PRC_UNREACH_PORT;
485 case ICMP_UNREACH_NET_PROHIB:
486 case ICMP_UNREACH_HOST_PROHIB:
487 case ICMP_UNREACH_FILTER_PROHIB:
488 code = PRC_UNREACH_ADMIN_PROHIB;
499 code += PRC_TIMXCEED_INTRANS;
505 code = PRC_PARAMPROB;
508 case ICMP_SOURCEQUENCH:
514 * Problem with datagram; advise higher level routines.
516 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
517 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
518 ICMPSTAT_INC(icps_badlen);
521 /* Discard ICMP's in response to multicast packets */
522 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
526 printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
528 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
530 * XXX if the packet contains [IPv4 AH TCP], we can't make a
531 * notification to TCP layer.
533 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
535 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
536 (void *)&icp->icmp_ip);
540 ICMPSTAT_INC(icps_badcode);
544 if (!V_icmpbmcastecho
545 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
546 ICMPSTAT_INC(icps_bmcastecho);
549 icp->icmp_type = ICMP_ECHOREPLY;
550 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
556 if (V_icmptstamprepl == 0)
558 if (!V_icmpbmcastecho
559 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
560 ICMPSTAT_INC(icps_bmcasttstamp);
563 if (icmplen < ICMP_TSLEN) {
564 ICMPSTAT_INC(icps_badlen);
567 icp->icmp_type = ICMP_TSTAMPREPLY;
568 icp->icmp_rtime = iptime();
569 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
570 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
576 if (V_icmpmaskrepl == 0)
579 * We are not able to respond with all ones broadcast
580 * unless we receive it over a point-to-point interface.
582 if (icmplen < ICMP_MASKLEN)
584 switch (ip->ip_dst.s_addr) {
586 case INADDR_BROADCAST:
588 icmpdst.sin_addr = ip->ip_src;
592 icmpdst.sin_addr = ip->ip_dst;
594 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
595 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
598 if (ia->ia_ifp == NULL) {
599 ifa_free(&ia->ia_ifa);
602 icp->icmp_type = ICMP_MASKREPLY;
603 if (V_icmpmaskfake == 0)
604 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
606 icp->icmp_mask = V_icmpmaskfake;
607 if (ip->ip_src.s_addr == 0) {
608 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
609 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
610 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
611 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
613 ifa_free(&ia->ia_ifa);
615 ICMPSTAT_INC(icps_reflect);
616 ICMPSTAT_INC(icps_outhist[icp->icmp_type]);
621 if (V_log_redirect) {
624 src = ntohl(ip->ip_src.s_addr);
625 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
626 gw = ntohl(icp->icmp_gwaddr.s_addr);
627 printf("icmp redirect from %d.%d.%d.%d: "
628 "%d.%d.%d.%d => %d.%d.%d.%d\n",
629 (int)(src >> 24), (int)((src >> 16) & 0xff),
630 (int)((src >> 8) & 0xff), (int)(src & 0xff),
631 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
632 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
633 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
634 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
637 * RFC1812 says we must ignore ICMP redirects if we
638 * are acting as router.
640 if (V_drop_redirect || V_ipforwarding)
644 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
645 icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
646 ICMPSTAT_INC(icps_badlen);
650 * Short circuit routing redirects to force
651 * immediate change in the kernel's routing
652 * tables. The message is also handed to anyone
653 * listening on a raw socket (e.g. the routing
654 * daemon for use in updating its tables).
656 icmpgw.sin_addr = ip->ip_src;
657 icmpdst.sin_addr = icp->icmp_gwaddr;
660 char buf[4 * sizeof "123"];
661 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
663 printf("redirect dst %s to %s\n",
664 buf, inet_ntoa(icp->icmp_gwaddr));
667 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
668 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
669 in_rtredirect((struct sockaddr *)&icmpsrc,
670 (struct sockaddr *)&icmpdst,
671 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
672 (struct sockaddr *)&icmpgw, fibnum);
674 pfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
678 * No kernel processing for the following;
679 * just fall through to send to raw listener.
682 case ICMP_ROUTERADVERT:
683 case ICMP_ROUTERSOLICIT:
684 case ICMP_TSTAMPREPLY:
700 * Reflect the ip packet back to the source
703 icmp_reflect(struct mbuf *m)
705 struct ip *ip = mtod(m, struct ip *);
708 struct in_ifaddr *ia;
710 struct mbuf *opts = 0;
711 int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
713 if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
714 IN_EXPERIMENTAL(ntohl(ip->ip_src.s_addr)) ||
715 IN_ZERONET(ntohl(ip->ip_src.s_addr)) ) {
716 m_freem(m); /* Bad return address */
717 ICMPSTAT_INC(icps_badaddr);
718 goto done; /* Ip_output() will check for broadcast */
722 ip->ip_dst = ip->ip_src;
725 * Source selection for ICMP replies:
727 * If the incoming packet was addressed directly to one of our
728 * own addresses, use dst as the src for the reply.
731 LIST_FOREACH(ia, INADDR_HASH(t.s_addr), ia_hash) {
732 if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr) {
733 t = IA_SIN(ia)->sin_addr;
741 * If the incoming packet was addressed to one of our broadcast
742 * addresses, use the first non-broadcast address which corresponds
743 * to the incoming interface.
745 ifp = m->m_pkthdr.rcvif;
746 if (ifp != NULL && ifp->if_flags & IFF_BROADCAST) {
748 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
749 if (ifa->ifa_addr->sa_family != AF_INET)
752 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
754 t = IA_SIN(ia)->sin_addr;
755 IF_ADDR_RUNLOCK(ifp);
759 IF_ADDR_RUNLOCK(ifp);
762 * If the packet was transiting through us, use the address of
763 * the interface the packet came through in. If that interface
764 * doesn't have a suitable IP address, the normal selection
767 if (V_icmp_rfi && ifp != NULL) {
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 incoming packet was not addressed directly to us, use
781 * designated interface for icmp replies specified by sysctl
782 * net.inet.icmp.reply_src (default not set). Otherwise continue
783 * with normal source selection.
785 if (V_reply_src[0] != '\0' && (ifp = ifunit(V_reply_src))) {
787 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
788 if (ifa->ifa_addr->sa_family != AF_INET)
791 t = IA_SIN(ia)->sin_addr;
792 IF_ADDR_RUNLOCK(ifp);
795 IF_ADDR_RUNLOCK(ifp);
798 * If the packet was transiting through us, use the address of
799 * the interface that is the closest to the packet source.
800 * When we don't have a route back to the packet source, stop here
801 * and drop the packet.
803 ia = ip_rtaddr(ip->ip_dst, M_GETFIB(m));
806 ICMPSTAT_INC(icps_noroute);
809 t = IA_SIN(ia)->sin_addr;
810 ifa_free(&ia->ia_ifa);
813 mac_netinet_icmp_replyinplace(m);
816 ip->ip_ttl = V_ip_defttl;
824 * Retrieve any source routing from the incoming packet;
825 * add on any record-route or timestamp options.
827 cp = (u_char *) (ip + 1);
828 if ((opts = ip_srcroute(m)) == 0 &&
829 (opts = m_gethdr(M_NOWAIT, MT_DATA))) {
830 opts->m_len = sizeof(struct in_addr);
831 mtod(opts, struct in_addr *)->s_addr = 0;
836 printf("icmp_reflect optlen %d rt %d => ",
837 optlen, opts->m_len);
839 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
840 opt = cp[IPOPT_OPTVAL];
841 if (opt == IPOPT_EOL)
843 if (opt == IPOPT_NOP)
846 if (cnt < IPOPT_OLEN + sizeof(*cp))
848 len = cp[IPOPT_OLEN];
849 if (len < IPOPT_OLEN + sizeof(*cp) ||
854 * Should check for overflow, but it "can't happen"
856 if (opt == IPOPT_RR || opt == IPOPT_TS ||
857 opt == IPOPT_SECURITY) {
859 mtod(opts, caddr_t) + opts->m_len, len);
863 /* Terminate & pad, if necessary */
864 cnt = opts->m_len % 4;
866 for (; cnt < 4; cnt++) {
867 *(mtod(opts, caddr_t) + opts->m_len) =
874 printf("%d\n", opts->m_len);
879 m_tag_delete_nonpersistent(m);
880 m->m_flags &= ~(M_BCAST|M_MCAST);
888 * Send an icmp packet back to the ip level,
889 * after supplying a checksum.
892 icmp_send(struct mbuf *m, struct mbuf *opts)
894 register struct ip *ip = mtod(m, struct ip *);
896 register struct icmp *icp;
898 hlen = ip->ip_hl << 2;
901 icp = mtod(m, struct icmp *);
903 icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
906 m->m_pkthdr.rcvif = (struct ifnet *)0;
909 char buf[4 * sizeof "123"];
910 strcpy(buf, inet_ntoa(ip->ip_dst));
911 printf("icmp_send dst %s src %s\n",
912 buf, inet_ntoa(ip->ip_src));
915 (void) ip_output(m, opts, NULL, 0, NULL, NULL);
919 * Return milliseconds since 00:00 GMT in network format.
928 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
933 * Return the next larger or smaller MTU plateau (table from RFC 1191)
934 * given current value MTU. If DIR is less than zero, a larger plateau
935 * is returned; otherwise, a smaller value is returned.
938 ip_next_mtu(int mtu, int dir)
940 static int mtutab[] = {
941 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1280, 1006, 508,
946 size = (sizeof mtutab) / (sizeof mtutab[0]);
948 for (i = 0; i < size; i++)
952 for (i = size - 1; i >= 0; i--)
955 if (mtu == mtutab[0])
964 * badport_bandlim() - check for ICMP bandwidth limit
966 * Return 0 if it is ok to send an ICMP error response, -1 if we have
967 * hit our bandwidth limit and it is not ok.
969 * If icmplim is <= 0, the feature is disabled and 0 is returned.
971 * For now we separate the TCP and UDP subsystems w/ different 'which'
972 * values. We may eventually remove this separation (and simplify the
975 * Note that the printing of the error message is delayed so we can
976 * properly print the icmp error rate that the system was trying to do
977 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
978 * the 'final' error, but it doesn't make sense to solve the printing
979 * delay with more complex code.
983 badport_bandlim(int which)
986 #define N(a) (sizeof (a) / sizeof (a[0]))
989 struct timeval lasttime;
991 } rates[BANDLIM_MAX+1] = {
992 { "icmp unreach response" },
993 { "icmp ping response" },
994 { "icmp tstamp response" },
995 { "closed port RST response" },
996 { "open port RST response" },
997 { "icmp6 unreach response" },
998 { "sctp ootb response" }
1002 * Return ok status if feature disabled or argument out of range.
1004 if (V_icmplim > 0 && (u_int) which < N(rates)) {
1005 struct rate *r = &rates[which];
1006 int opps = r->curpps;
1008 if (!ppsratecheck(&r->lasttime, &r->curpps, V_icmplim))
1009 return -1; /* discard packet */
1011 * If we've dropped below the threshold after having
1012 * rate-limited traffic print the message. This preserves
1013 * the previous behaviour at the expense of added complexity.
1015 if (V_icmplim_output && opps > V_icmplim)
1016 log(LOG_NOTICE, "Limiting %s from %d to %d packets/sec\n",
1017 r->type, opps, V_icmplim);
1019 return 0; /* okay to send packet */