HAMMER 60I/Many: Mirroring
[dragonfly.git] / sys / netinet / ip_icmp.c
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1 /*
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
7 * are met:
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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
33 * @(#)ip_icmp.c 8.2 (Berkeley) 1/4/94
34 * $FreeBSD: src/sys/netinet/ip_icmp.c,v 1.39.2.19 2003/01/24 05:11:34 sam Exp $
35 * $DragonFly: src/sys/netinet/ip_icmp.c,v 1.30 2008/06/09 11:24:24 sephe Exp $
38 #include "opt_ipsec.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/mbuf.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
45 #include <sys/time.h>
46 #include <sys/kernel.h>
47 #include <sys/sysctl.h>
48 #include <sys/in_cksum.h>
50 #include <machine/stdarg.h>
52 #include <net/if.h>
53 #include <net/if_types.h>
54 #include <net/route.h>
56 #define _IP_VHL
57 #include <netinet/in.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/icmp_var.h>
65 #ifdef IPSEC
66 #include <netinet6/ipsec.h>
67 #include <netproto/key/key.h>
68 #endif
70 #ifdef FAST_IPSEC
71 #include <netproto/ipsec/ipsec.h>
72 #include <netproto/ipsec/key.h>
73 #define IPSEC
74 #endif
77 * ICMP routines: error generation, receive packet processing, and
78 * routines to turnaround packets back to the originator, and
79 * host table maintenance routines.
82 struct icmpstat icmpstat;
83 SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW,
84 &icmpstat, icmpstat, "");
86 static int icmpmaskrepl = 0;
87 SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW,
88 &icmpmaskrepl, 0, "");
90 static int drop_redirect = 0;
91 SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW,
92 &drop_redirect, 0, "");
94 static int log_redirect = 0;
95 SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW,
96 &log_redirect, 0, "");
98 #ifdef ICMP_BANDLIM
101 * ICMP error-response bandwidth limiting sysctl. If not enabled, sysctl
102 * variable content is -1 and read-only.
105 static int icmplim = 200;
106 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW,
107 &icmplim, 0, "");
108 #else
110 static int icmplim = -1;
111 SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RD,
112 &icmplim, 0, "");
114 #endif
116 static int icmplim_output = 1;
117 SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW,
118 &icmplim_output, 0, "");
121 * ICMP broadcast echo sysctl
124 static int icmpbmcastecho = 0;
125 SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW,
126 &icmpbmcastecho, 0, "");
129 #ifdef ICMPPRINTFS
130 int icmpprintfs = 0;
131 #endif
133 static void icmp_reflect (struct mbuf *);
134 static void icmp_send (struct mbuf *, struct mbuf *, struct route *);
136 extern struct protosw inetsw[];
139 * Generate an error packet of type error
140 * in response to bad packet ip.
142 void
143 icmp_error(struct mbuf *n, int type, int code, n_long dest, int destmtu)
145 struct ip *oip = mtod(n, struct ip *), *nip;
146 unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2;
147 struct icmp *icp;
148 struct mbuf *m;
149 unsigned icmplen;
151 #ifdef ICMPPRINTFS
152 if (icmpprintfs)
153 kprintf("icmp_error(%p, %d, %d)\n", oip, type, code);
154 #endif
155 if (type != ICMP_REDIRECT)
156 icmpstat.icps_error++;
158 * Don't send error if the original packet was encrypted.
159 * Don't send error if not the first fragment of message.
160 * Don't error if the old packet protocol was ICMP
161 * error message, only known informational types.
163 if (n->m_flags & M_DECRYPTED)
164 goto freeit;
165 if (oip->ip_off &~ (IP_MF|IP_DF))
166 goto freeit;
167 if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
168 n->m_len >= oiplen + ICMP_MINLEN &&
169 !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
170 icmpstat.icps_oldicmp++;
171 goto freeit;
173 /* Don't send error in response to a multicast or broadcast packet */
174 if (n->m_flags & (M_BCAST|M_MCAST))
175 goto freeit;
177 * First, formulate icmp message
179 m = m_gethdr(MB_DONTWAIT, MT_HEADER);
180 if (m == NULL)
181 goto freeit;
182 icmplen = min(oiplen + 8, oip->ip_len);
183 if (icmplen < sizeof(struct ip))
184 panic("icmp_error: bad length");
185 m->m_len = icmplen + ICMP_MINLEN;
186 MH_ALIGN(m, m->m_len);
187 icp = mtod(m, struct icmp *);
188 if ((u_int)type > ICMP_MAXTYPE)
189 panic("icmp_error");
190 icmpstat.icps_outhist[type]++;
191 icp->icmp_type = type;
192 if (type == ICMP_REDIRECT)
193 icp->icmp_gwaddr.s_addr = dest;
194 else {
195 icp->icmp_void = 0;
197 * The following assignments assume an overlay with the
198 * zeroed icmp_void field.
200 if (type == ICMP_PARAMPROB) {
201 icp->icmp_pptr = code;
202 code = 0;
203 } else if (type == ICMP_UNREACH &&
204 code == ICMP_UNREACH_NEEDFRAG && destmtu) {
205 icp->icmp_nextmtu = htons(destmtu);
209 icp->icmp_code = code;
210 m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
211 nip = &icp->icmp_ip;
214 * Convert fields to network representation.
216 nip->ip_len = htons(nip->ip_len);
217 nip->ip_off = htons(nip->ip_off);
220 * Now, copy old ip header (without options)
221 * in front of icmp message.
223 if (m->m_data - sizeof(struct ip) < m->m_pktdat)
224 panic("icmp len");
225 m->m_data -= sizeof(struct ip);
226 m->m_len += sizeof(struct ip);
227 m->m_pkthdr.len = m->m_len;
228 m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
229 nip = mtod(m, struct ip *);
230 bcopy(oip, nip, sizeof(struct ip));
231 nip->ip_len = m->m_len;
232 nip->ip_vhl = IP_VHL_BORING;
233 nip->ip_p = IPPROTO_ICMP;
234 nip->ip_tos = 0;
235 m->m_pkthdr.fw_flags |= n->m_pkthdr.fw_flags & FW_MBUF_GENERATED;
236 icmp_reflect(m);
238 freeit:
239 m_freem(n);
243 * Process a received ICMP message.
245 void
246 icmp_input(struct mbuf *m, ...)
248 struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET };
249 struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET };
250 struct sockaddr_in icmpgw = { sizeof(struct sockaddr_in), AF_INET };
251 struct icmp *icp;
252 struct in_ifaddr *ia;
253 struct ip *ip = mtod(m, struct ip *);
254 void (*ctlfunc) (int, struct sockaddr *, void *);
255 int icmplen = ip->ip_len;
256 int i, hlen;
257 int code, off, proto;
258 __va_list ap;
260 __va_start(ap, m);
261 off = __va_arg(ap, int);
262 proto = __va_arg(ap, int);
263 __va_end(ap);
265 hlen = off;
268 * Locate icmp structure in mbuf, and check
269 * that not corrupted and of at least minimum length.
271 #ifdef ICMPPRINTFS
272 if (icmpprintfs) {
273 char buf[sizeof "aaa.bbb.ccc.ddd"];
275 strcpy(buf, inet_ntoa(ip->ip_src));
276 kprintf("icmp_input from %s to %s, len %d\n",
277 buf, inet_ntoa(ip->ip_dst), icmplen);
279 #endif
280 if (icmplen < ICMP_MINLEN) {
281 icmpstat.icps_tooshort++;
282 goto freeit;
284 i = hlen + min(icmplen, ICMP_ADVLENMIN);
285 if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
286 icmpstat.icps_tooshort++;
287 return;
289 ip = mtod(m, struct ip *);
290 m->m_len -= hlen;
291 m->m_data += hlen;
292 icp = mtod(m, struct icmp *);
293 if (in_cksum(m, icmplen)) {
294 icmpstat.icps_checksum++;
295 goto freeit;
297 m->m_len += hlen;
298 m->m_data -= hlen;
300 if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type == IFT_FAITH) {
302 * Deliver very specific ICMP type only.
304 switch (icp->icmp_type) {
305 case ICMP_UNREACH:
306 case ICMP_TIMXCEED:
307 break;
308 default:
309 goto freeit;
313 #ifdef ICMPPRINTFS
314 if (icmpprintfs)
315 kprintf("icmp_input, type %d code %d\n", icp->icmp_type,
316 icp->icmp_code);
317 #endif
320 * Message type specific processing.
322 if (icp->icmp_type > ICMP_MAXTYPE)
323 goto raw;
324 icmpstat.icps_inhist[icp->icmp_type]++;
325 code = icp->icmp_code;
326 switch (icp->icmp_type) {
328 case ICMP_UNREACH:
329 switch (code) {
330 case ICMP_UNREACH_NET:
331 case ICMP_UNREACH_HOST:
332 case ICMP_UNREACH_SRCFAIL:
333 case ICMP_UNREACH_NET_UNKNOWN:
334 case ICMP_UNREACH_HOST_UNKNOWN:
335 case ICMP_UNREACH_ISOLATED:
336 case ICMP_UNREACH_TOSNET:
337 case ICMP_UNREACH_TOSHOST:
338 case ICMP_UNREACH_HOST_PRECEDENCE:
339 case ICMP_UNREACH_PRECEDENCE_CUTOFF:
340 code = PRC_UNREACH_NET;
341 break;
343 case ICMP_UNREACH_NEEDFRAG:
344 code = PRC_MSGSIZE;
345 break;
348 * RFC 1122, Sections 3.2.2.1 and 4.2.3.9.
349 * Treat subcodes 2,3 as immediate RST
351 case ICMP_UNREACH_PROTOCOL:
352 case ICMP_UNREACH_PORT:
353 code = PRC_UNREACH_PORT;
354 break;
356 case ICMP_UNREACH_NET_PROHIB:
357 case ICMP_UNREACH_HOST_PROHIB:
358 case ICMP_UNREACH_FILTER_PROHIB:
359 code = PRC_UNREACH_ADMIN_PROHIB;
360 break;
362 default:
363 goto badcode;
365 goto deliver;
367 case ICMP_TIMXCEED:
368 if (code > 1)
369 goto badcode;
370 code += PRC_TIMXCEED_INTRANS;
371 goto deliver;
373 case ICMP_PARAMPROB:
374 if (code > 1)
375 goto badcode;
376 code = PRC_PARAMPROB;
377 goto deliver;
379 case ICMP_SOURCEQUENCH:
380 if (code)
381 goto badcode;
382 code = PRC_QUENCH;
383 deliver:
385 * Problem with datagram; advise higher level routines.
387 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
388 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
389 icmpstat.icps_badlen++;
390 goto freeit;
392 icp->icmp_ip.ip_len = ntohs(icp->icmp_ip.ip_len);
393 /* Discard ICMP's in response to multicast packets */
394 if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr)))
395 goto badcode;
396 #ifdef ICMPPRINTFS
397 if (icmpprintfs)
398 kprintf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
399 #endif
400 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
401 #if 1
403 * MTU discovery:
404 * If we got a needfrag and there is a host route to the
405 * original destination, and the MTU is not locked, then
406 * set the MTU in the route to the suggested new value
407 * (if given) and then notify as usual. The ULPs will
408 * notice that the MTU has changed and adapt accordingly.
409 * If no new MTU was suggested, then we guess a new one
410 * less than the current value. If the new MTU is
411 * unreasonably small (arbitrarily set at 296), then
412 * we reset the MTU to the interface value and enable the
413 * lock bit, indicating that we are no longer doing MTU
414 * discovery.
416 if (code == PRC_MSGSIZE) {
417 struct rtentry *rt;
418 int mtu;
420 rt = rtpurelookup((struct sockaddr *)&icmpsrc);
421 if (rt != NULL && (rt->rt_flags & RTF_HOST) &&
422 !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
423 mtu = ntohs(icp->icmp_nextmtu);
424 if (!mtu)
425 mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu,
427 #ifdef DEBUG_MTUDISC
428 kprintf("MTU for %s reduced to %d\n",
429 inet_ntoa(icmpsrc.sin_addr), mtu);
430 #endif
431 if (mtu < 296) {
432 /* rt->rt_rmx.rmx_mtu =
433 rt->rt_ifp->if_mtu; */
434 rt->rt_rmx.rmx_locks |= RTV_MTU;
435 } else if (rt->rt_rmx.rmx_mtu > mtu) {
436 rt->rt_rmx.rmx_mtu = mtu;
439 if (rt != NULL)
440 --rt->rt_refcnt;
442 #endif
444 * XXX if the packet contains [IPv4 AH TCP], we can't make a
445 * notification to TCP layer.
447 ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
448 if (ctlfunc)
449 (*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
450 &icp->icmp_ip);
451 break;
453 badcode:
454 icmpstat.icps_badcode++;
455 break;
457 case ICMP_ECHO:
458 if (!icmpbmcastecho
459 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
460 icmpstat.icps_bmcastecho++;
461 break;
463 icp->icmp_type = ICMP_ECHOREPLY;
464 #ifdef ICMP_BANDLIM
465 if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0)
466 goto freeit;
467 else
468 #endif
469 goto reflect;
471 case ICMP_TSTAMP:
472 if (!icmpbmcastecho
473 && (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
474 icmpstat.icps_bmcasttstamp++;
475 break;
477 if (icmplen < ICMP_TSLEN) {
478 icmpstat.icps_badlen++;
479 break;
481 icp->icmp_type = ICMP_TSTAMPREPLY;
482 icp->icmp_rtime = iptime();
483 icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
484 #ifdef ICMP_BANDLIM
485 if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0)
486 goto freeit;
487 else
488 #endif
489 goto reflect;
491 case ICMP_MASKREQ:
492 if (icmpmaskrepl == 0)
493 break;
495 * We are not able to respond with all ones broadcast
496 * unless we receive it over a point-to-point interface.
498 if (icmplen < ICMP_MASKLEN)
499 break;
500 switch (ip->ip_dst.s_addr) {
502 case INADDR_BROADCAST:
503 case INADDR_ANY:
504 icmpdst.sin_addr = ip->ip_src;
505 break;
507 default:
508 icmpdst.sin_addr = ip->ip_dst;
510 ia = (struct in_ifaddr *)ifaof_ifpforaddr(
511 (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif);
512 if (ia == 0)
513 break;
514 if (ia->ia_ifp == 0)
515 break;
516 icp->icmp_type = ICMP_MASKREPLY;
517 icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
518 if (ip->ip_src.s_addr == 0) {
519 if (ia->ia_ifp->if_flags & IFF_BROADCAST)
520 ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr;
521 else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
522 ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
524 reflect:
525 ip->ip_len += hlen; /* since ip_input deducts this */
526 icmpstat.icps_reflect++;
527 icmpstat.icps_outhist[icp->icmp_type]++;
528 icmp_reflect(m);
529 return;
531 case ICMP_REDIRECT:
532 if (log_redirect) {
533 u_long src, dst, gw;
535 src = ntohl(ip->ip_src.s_addr);
536 dst = ntohl(icp->icmp_ip.ip_dst.s_addr);
537 gw = ntohl(icp->icmp_gwaddr.s_addr);
538 kprintf("icmp redirect from %d.%d.%d.%d: "
539 "%d.%d.%d.%d => %d.%d.%d.%d\n",
540 (int)(src >> 24), (int)((src >> 16) & 0xff),
541 (int)((src >> 8) & 0xff), (int)(src & 0xff),
542 (int)(dst >> 24), (int)((dst >> 16) & 0xff),
543 (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
544 (int)(gw >> 24), (int)((gw >> 16) & 0xff),
545 (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
547 if (drop_redirect)
548 break;
549 if (code > 3)
550 goto badcode;
551 if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
552 IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) {
553 icmpstat.icps_badlen++;
554 break;
557 * Short circuit routing redirects to force
558 * immediate change in the kernel's routing
559 * tables. The message is also handed to anyone
560 * listening on a raw socket (e.g. the routing
561 * daemon for use in updating its tables).
563 icmpgw.sin_addr = ip->ip_src;
564 icmpdst.sin_addr = icp->icmp_gwaddr;
565 #ifdef ICMPPRINTFS
566 if (icmpprintfs) {
567 char buf[sizeof "aaa.bbb.ccc.ddd"];
569 strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
570 kprintf("redirect dst %s to %s\n",
571 buf, inet_ntoa(icp->icmp_gwaddr));
573 #endif
574 icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
575 rtredirect((struct sockaddr *)&icmpsrc,
576 (struct sockaddr *)&icmpdst,
577 (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
578 (struct sockaddr *)&icmpgw);
579 kpfctlinput(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc);
580 #ifdef IPSEC
581 key_sa_routechange((struct sockaddr *)&icmpsrc);
582 #endif
583 break;
586 * No kernel processing for the following;
587 * just fall through to send to raw listener.
589 case ICMP_ECHOREPLY:
590 case ICMP_ROUTERADVERT:
591 case ICMP_ROUTERSOLICIT:
592 case ICMP_TSTAMPREPLY:
593 case ICMP_IREQREPLY:
594 case ICMP_MASKREPLY:
595 default:
596 break;
599 raw:
600 rip_input(m, off, proto);
601 return;
603 freeit:
604 m_freem(m);
608 * Reflect the ip packet back to the source
610 static void
611 icmp_reflect(struct mbuf *m)
613 struct ip *ip = mtod(m, struct ip *);
614 struct in_ifaddr *ia;
615 struct in_ifaddr_container *iac;
616 struct in_addr t;
617 struct mbuf *opts = 0;
618 int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip);
619 struct route *ro = NULL, rt;
621 if (!in_canforward(ip->ip_src) &&
622 ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) !=
623 (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
624 m_freem(m); /* Bad return address */
625 icmpstat.icps_badaddr++;
626 goto done; /* Ip_output() will check for broadcast */
628 t = ip->ip_dst;
629 ip->ip_dst = ip->ip_src;
630 ro = &rt;
631 bzero(ro, sizeof *ro);
633 * If the incoming packet was addressed directly to us,
634 * use dst as the src for the reply. Otherwise (broadcast
635 * or anonymous), use the address which corresponds
636 * to the incoming interface.
638 ia = NULL;
639 LIST_FOREACH(iac, INADDR_HASH(t.s_addr), ia_hash) {
640 if (t.s_addr == IA_SIN(iac->ia)->sin_addr.s_addr) {
641 ia = iac->ia;
642 goto match;
645 if (m->m_pkthdr.rcvif != NULL &&
646 m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
647 struct ifaddr_container *ifac;
649 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
650 ifa_link) {
651 struct ifaddr *ifa = ifac->ifa;
653 if (ifa->ifa_addr->sa_family != AF_INET)
654 continue;
655 ia = ifatoia(ifa);
656 if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
657 t.s_addr)
658 goto match;
661 ia = ip_rtaddr(ip->ip_dst, ro);
662 /* We need a route to do anything useful. */
663 if (ia == NULL) {
664 m_freem(m);
665 icmpstat.icps_noroute++;
666 goto done;
668 match:
669 t = IA_SIN(ia)->sin_addr;
670 ip->ip_src = t;
671 ip->ip_ttl = ip_defttl;
673 if (optlen > 0) {
674 u_char *cp;
675 int opt, cnt;
676 u_int len;
679 * Retrieve any source routing from the incoming packet;
680 * add on any record-route or timestamp options.
682 cp = (u_char *) (ip + 1);
683 if ((opts = ip_srcroute()) == 0 &&
684 (opts = m_gethdr(MB_DONTWAIT, MT_HEADER))) {
685 opts->m_len = sizeof(struct in_addr);
686 mtod(opts, struct in_addr *)->s_addr = 0;
688 if (opts) {
689 #ifdef ICMPPRINTFS
690 if (icmpprintfs)
691 kprintf("icmp_reflect optlen %d rt %d => ",
692 optlen, opts->m_len);
693 #endif
694 for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
695 opt = cp[IPOPT_OPTVAL];
696 if (opt == IPOPT_EOL)
697 break;
698 if (opt == IPOPT_NOP)
699 len = 1;
700 else {
701 if (cnt < IPOPT_OLEN + sizeof *cp)
702 break;
703 len = cp[IPOPT_OLEN];
704 if (len < IPOPT_OLEN + sizeof *cp ||
705 len > cnt)
706 break;
709 * Should check for overflow, but it
710 * "can't happen".
712 if (opt == IPOPT_RR || opt == IPOPT_TS ||
713 opt == IPOPT_SECURITY) {
714 bcopy(cp,
715 mtod(opts, caddr_t) + opts->m_len,
716 len);
717 opts->m_len += len;
720 /* Terminate & pad, if necessary */
721 cnt = opts->m_len % 4;
722 if (cnt) {
723 for (; cnt < 4; cnt++) {
724 *(mtod(opts, caddr_t) + opts->m_len) =
725 IPOPT_EOL;
726 opts->m_len++;
729 #ifdef ICMPPRINTFS
730 if (icmpprintfs)
731 kprintf("%d\n", opts->m_len);
732 #endif
735 * Now strip out original options by copying rest of first
736 * mbuf's data back, and adjust the IP length.
738 ip->ip_len -= optlen;
739 ip->ip_vhl = IP_VHL_BORING;
740 m->m_len -= optlen;
741 if (m->m_flags & M_PKTHDR)
742 m->m_pkthdr.len -= optlen;
743 optlen += sizeof(struct ip);
744 bcopy((caddr_t)ip + optlen, ip + 1,
745 m->m_len - sizeof(struct ip));
747 m->m_pkthdr.fw_flags &= FW_MBUF_GENERATED;
748 m->m_flags &= ~(M_BCAST|M_MCAST);
749 icmp_send(m, opts, ro);
750 done:
751 if (opts)
752 m_free(opts);
753 if (ro && ro->ro_rt)
754 RTFREE(ro->ro_rt);
758 * Send an icmp packet back to the ip level,
759 * after supplying a checksum.
761 static void
762 icmp_send(struct mbuf *m, struct mbuf *opts, struct route *rt)
764 struct ip *ip = mtod(m, struct ip *);
765 int hlen;
766 struct icmp *icp;
768 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
769 m->m_data += hlen;
770 m->m_len -= hlen;
771 icp = mtod(m, struct icmp *);
772 icp->icmp_cksum = 0;
773 icp->icmp_cksum = in_cksum(m, ip->ip_len - hlen);
774 m->m_data -= hlen;
775 m->m_len += hlen;
776 m->m_pkthdr.rcvif = (struct ifnet *)0;
777 #ifdef ICMPPRINTFS
778 if (icmpprintfs) {
779 char buf[sizeof "aaa.bbb.ccc.ddd"];
781 strcpy(buf, inet_ntoa(ip->ip_dst));
782 kprintf("icmp_send dst %s src %s\n", buf, inet_ntoa(ip->ip_src));
784 #endif
785 ip_output(m, opts, rt, 0, NULL, NULL);
788 n_time
789 iptime(void)
791 struct timeval atv;
792 u_long t;
794 getmicrotime(&atv);
795 t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
796 return (htonl(t));
799 #if 1
801 * Return the next larger or smaller MTU plateau (table from RFC 1191)
802 * given current value MTU. If DIR is less than zero, a larger plateau
803 * is returned; otherwise, a smaller value is returned.
806 ip_next_mtu(int mtu, int dir)
808 static int mtutab[] = {
809 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296,
810 68, 0
812 int i;
814 for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) {
815 if (mtu >= mtutab[i])
816 break;
819 if (dir < 0) {
820 if (i == 0) {
821 return 0;
822 } else {
823 return mtutab[i - 1];
825 } else {
826 if (mtutab[i] == 0) {
827 return 0;
828 } else if(mtu > mtutab[i]) {
829 return mtutab[i];
830 } else {
831 return mtutab[i + 1];
835 #endif
837 #ifdef ICMP_BANDLIM
839 * badport_bandlim() - check for ICMP bandwidth limit
841 * Return 0 if it is ok to send an ICMP error response, -1 if we have
842 * hit our bandwidth limit and it is not ok.
844 * If icmplim is <= 0, the feature is disabled and 0 is returned.
846 * For now we separate the TCP and UDP subsystems w/ different 'which'
847 * values. We may eventually remove this separation (and simplify the
848 * code further).
850 * Note that the printing of the error message is delayed so we can
851 * properly print the icmp error rate that the system was trying to do
852 * (i.e. 22000/100 pps, etc...). This can cause long delays in printing
853 * the 'final' error, but it doesn't make sense to solve the printing
854 * delay with more complex code.
857 badport_bandlim(int which)
859 static int lticks[BANDLIM_MAX + 1];
860 static int lpackets[BANDLIM_MAX + 1];
861 int dticks;
862 const char *bandlimittype[] = {
863 "Limiting icmp unreach response",
864 "Limiting icmp ping response",
865 "Limiting icmp tstamp response",
866 "Limiting closed port RST response",
867 "Limiting open port RST response"
871 * Return ok status if feature disabled or argument out of
872 * ranage.
875 if (icmplim <= 0 || which > BANDLIM_MAX || which < 0)
876 return(0);
877 dticks = ticks - lticks[which];
880 * reset stats when cumulative dt exceeds one second.
883 if ((unsigned int)dticks > hz) {
884 if (lpackets[which] > icmplim && icmplim_output) {
885 kprintf("%s from %d to %d packets per second\n",
886 bandlimittype[which],
887 lpackets[which],
888 icmplim
891 lticks[which] = ticks;
892 lpackets[which] = 0;
896 * bump packet count
899 if (++lpackets[which] > icmplim) {
900 return(-1);
902 return(0);
904 #endif