Annotation of sys/netinet/ip_icmp.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: ip_icmp.c,v 1.76 2007/06/11 11:29:35 henning Exp $ */
! 2: /* $NetBSD: ip_icmp.c,v 1.19 1996/02/13 23:42:22 christos Exp $ */
! 3:
! 4: /*
! 5: * Copyright (c) 1982, 1986, 1988, 1993
! 6: * The Regents of the University of California. All rights reserved.
! 7: *
! 8: * Redistribution and use in source and binary forms, with or without
! 9: * modification, are permitted provided that the following conditions
! 10: * are met:
! 11: * 1. Redistributions of source code must retain the above copyright
! 12: * notice, this list of conditions and the following disclaimer.
! 13: * 2. Redistributions in binary form must reproduce the above copyright
! 14: * notice, this list of conditions and the following disclaimer in the
! 15: * documentation and/or other materials provided with the distribution.
! 16: * 3. Neither the name of the University nor the names of its contributors
! 17: * may be used to endorse or promote products derived from this software
! 18: * without specific prior written permission.
! 19: *
! 20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 30: * SUCH DAMAGE.
! 31: *
! 32: * @(#)COPYRIGHT 1.1 (NRL) 17 January 1995
! 33: *
! 34: * NRL grants permission for redistribution and use in source and binary
! 35: * forms, with or without modification, of the software and documentation
! 36: * created at NRL provided that the following conditions are met:
! 37: *
! 38: * 1. Redistributions of source code must retain the above copyright
! 39: * notice, this list of conditions and the following disclaimer.
! 40: * 2. Redistributions in binary form must reproduce the above copyright
! 41: * notice, this list of conditions and the following disclaimer in the
! 42: * documentation and/or other materials provided with the distribution.
! 43: * 3. All advertising materials mentioning features or use of this software
! 44: * must display the following acknowledgements:
! 45: * This product includes software developed by the University of
! 46: * California, Berkeley and its contributors.
! 47: * This product includes software developed at the Information
! 48: * Technology Division, US Naval Research Laboratory.
! 49: * 4. Neither the name of the NRL nor the names of its contributors
! 50: * may be used to endorse or promote products derived from this software
! 51: * without specific prior written permission.
! 52: *
! 53: * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS
! 54: * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
! 55: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
! 56: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR
! 57: * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
! 58: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
! 59: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
! 60: * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
! 61: * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
! 62: * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
! 63: * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
! 64: *
! 65: * The views and conclusions contained in the software and documentation
! 66: * are those of the authors and should not be interpreted as representing
! 67: * official policies, either expressed or implied, of the US Naval
! 68: * Research Laboratory (NRL).
! 69: */
! 70:
! 71: #include "carp.h"
! 72:
! 73: #include <sys/param.h>
! 74: #include <sys/systm.h>
! 75: #include <sys/mbuf.h>
! 76: #include <sys/protosw.h>
! 77: #include <sys/socket.h>
! 78: #include <sys/sysctl.h>
! 79:
! 80: #include <net/if.h>
! 81: #include <net/route.h>
! 82:
! 83: #include <netinet/in.h>
! 84: #include <netinet/in_systm.h>
! 85: #include <netinet/in_var.h>
! 86: #include <netinet/ip.h>
! 87: #include <netinet/ip_icmp.h>
! 88: #include <netinet/ip_var.h>
! 89: #include <netinet/icmp_var.h>
! 90:
! 91: #if NCARP > 0
! 92: #include <net/if_types.h>
! 93: #include <netinet/ip_carp.h>
! 94: #endif
! 95:
! 96: /*
! 97: * ICMP routines: error generation, receive packet processing, and
! 98: * routines to turnaround packets back to the originator, and
! 99: * host table maintenance routines.
! 100: */
! 101:
! 102: int icmpmaskrepl = 0;
! 103: int icmpbmcastecho = 0;
! 104: int icmptstamprepl = 1;
! 105: #ifdef ICMPPRINTFS
! 106: int icmpprintfs = 0;
! 107: #endif
! 108: int icmperrppslim = 100;
! 109: int icmperrpps_count = 0;
! 110: struct timeval icmperrppslim_last;
! 111: int icmp_rediraccept = 1;
! 112: int icmp_redirtimeout = 10 * 60;
! 113: static struct rttimer_queue *icmp_redirect_timeout_q = NULL;
! 114: struct icmpstat icmpstat;
! 115:
! 116: int *icmpctl_vars[ICMPCTL_MAXID] = ICMPCTL_VARS;
! 117:
! 118: void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *);
! 119: int icmp_ratelimit(const struct in_addr *, const int, const int);
! 120: void icmp_redirect_timeout(struct rtentry *, struct rttimer *);
! 121:
! 122: extern struct protosw inetsw[];
! 123:
! 124: void
! 125: icmp_init(void)
! 126: {
! 127: /*
! 128: * This is only useful if the user initializes redirtimeout to
! 129: * something other than zero.
! 130: */
! 131: if (icmp_redirtimeout != 0) {
! 132: icmp_redirect_timeout_q =
! 133: rt_timer_queue_create(icmp_redirtimeout);
! 134: }
! 135: }
! 136:
! 137: struct mbuf *
! 138: icmp_do_error(struct mbuf *n, int type, int code, n_long dest, int destmtu)
! 139: {
! 140: struct ip *oip = mtod(n, struct ip *), *nip;
! 141: unsigned oiplen = oip->ip_hl << 2;
! 142: struct icmp *icp;
! 143: struct mbuf *m;
! 144: unsigned icmplen, mblen;
! 145:
! 146: #ifdef ICMPPRINTFS
! 147: if (icmpprintfs)
! 148: printf("icmp_error(%x, %d, %d)\n", oip, type, code);
! 149: #endif
! 150: if (type != ICMP_REDIRECT)
! 151: icmpstat.icps_error++;
! 152: /*
! 153: * Don't send error if not the first fragment of message.
! 154: * Don't error if the old packet protocol was ICMP
! 155: * error message, only known informational types.
! 156: */
! 157: if (oip->ip_off & htons(IP_OFFMASK))
! 158: goto freeit;
! 159: if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
! 160: n->m_len >= oiplen + ICMP_MINLEN &&
! 161: !ICMP_INFOTYPE(((struct icmp *)
! 162: ((caddr_t)oip + oiplen))->icmp_type)) {
! 163: icmpstat.icps_oldicmp++;
! 164: goto freeit;
! 165: }
! 166: /* Don't send error in response to a multicast or broadcast packet */
! 167: if (n->m_flags & (M_BCAST|M_MCAST))
! 168: goto freeit;
! 169:
! 170: /*
! 171: * First, do a rate limitation check.
! 172: */
! 173: if (icmp_ratelimit(&oip->ip_src, type, code))
! 174: goto freeit; /* XXX stat */
! 175:
! 176: /*
! 177: * Now, formulate icmp message
! 178: */
! 179: icmplen = oiplen + min(8, ntohs(oip->ip_len));
! 180: /*
! 181: * Defend against mbuf chains shorter than oip->ip_len:
! 182: */
! 183: mblen = 0;
! 184: for (m = n; m && (mblen < icmplen); m = m->m_next)
! 185: mblen += m->m_len;
! 186: icmplen = min(mblen, icmplen);
! 187:
! 188: /*
! 189: * As we are not required to return everything we have,
! 190: * we return whatever we can return at ease.
! 191: *
! 192: * Note that ICMP datagrams longer than 576 octets are out of spec
! 193: * according to RFC1812;
! 194: */
! 195:
! 196: KASSERT(ICMP_MINLEN <= MCLBYTES);
! 197:
! 198: if (icmplen + ICMP_MINLEN > MCLBYTES)
! 199: icmplen = MCLBYTES - ICMP_MINLEN - sizeof (struct ip);
! 200:
! 201: m = m_gethdr(M_DONTWAIT, MT_HEADER);
! 202: if (m && (sizeof (struct ip) + icmplen + ICMP_MINLEN > MHLEN)) {
! 203: MCLGET(m, M_DONTWAIT);
! 204: if ((m->m_flags & M_EXT) == 0) {
! 205: m_freem(m);
! 206: m = NULL;
! 207: }
! 208: }
! 209: if (m == NULL)
! 210: goto freeit;
! 211: m->m_len = icmplen + ICMP_MINLEN;
! 212: if ((m->m_flags & M_EXT) == 0)
! 213: MH_ALIGN(m, m->m_len);
! 214: icp = mtod(m, struct icmp *);
! 215: if ((u_int)type > ICMP_MAXTYPE)
! 216: panic("icmp_error");
! 217: icmpstat.icps_outhist[type]++;
! 218: icp->icmp_type = type;
! 219: if (type == ICMP_REDIRECT)
! 220: icp->icmp_gwaddr.s_addr = dest;
! 221: else {
! 222: icp->icmp_void = 0;
! 223: /*
! 224: * The following assignments assume an overlay with the
! 225: * zeroed icmp_void field.
! 226: */
! 227: if (type == ICMP_PARAMPROB) {
! 228: icp->icmp_pptr = code;
! 229: code = 0;
! 230: } else if (type == ICMP_UNREACH &&
! 231: code == ICMP_UNREACH_NEEDFRAG && destmtu)
! 232: icp->icmp_nextmtu = htons(destmtu);
! 233: }
! 234:
! 235: icp->icmp_code = code;
! 236: m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
! 237:
! 238: /*
! 239: * Now, copy old ip header (without options)
! 240: * in front of icmp message.
! 241: */
! 242: if ((m->m_flags & M_EXT) == 0 &&
! 243: m->m_data - sizeof(struct ip) < m->m_pktdat)
! 244: panic("icmp len");
! 245: m->m_data -= sizeof(struct ip);
! 246: m->m_len += sizeof(struct ip);
! 247: m->m_pkthdr.len = m->m_len;
! 248: m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
! 249: nip = mtod(m, struct ip *);
! 250: /* ip_v set in ip_output */
! 251: nip->ip_hl = sizeof(struct ip) >> 2;
! 252: nip->ip_tos = 0;
! 253: nip->ip_len = htons(m->m_len);
! 254: /* ip_id set in ip_output */
! 255: nip->ip_off = 0;
! 256: /* ip_ttl set in icmp_reflect */
! 257: nip->ip_p = IPPROTO_ICMP;
! 258: nip->ip_src = oip->ip_src;
! 259: nip->ip_dst = oip->ip_dst;
! 260:
! 261: /* move PF_GENERATED to new packet, if existant XXX preserve more? */
! 262: if (n->m_pkthdr.pf.flags & PF_TAG_GENERATED)
! 263: m->m_pkthdr.pf.flags |= PF_TAG_GENERATED;
! 264:
! 265: m_freem(n);
! 266: return (m);
! 267:
! 268: freeit:
! 269: m_freem(n);
! 270: return (NULL);
! 271: }
! 272:
! 273: /*
! 274: * Generate an error packet of type error
! 275: * in response to bad packet ip.
! 276: *
! 277: * The ip packet inside has ip_off and ip_len in host byte order.
! 278: */
! 279: void
! 280: icmp_error(struct mbuf *n, int type, int code, n_long dest, int destmtu)
! 281: {
! 282: struct mbuf *m;
! 283:
! 284: m = icmp_do_error(n, type, code, dest, destmtu);
! 285: if (m != NULL)
! 286: icmp_reflect(m);
! 287: }
! 288:
! 289: struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET };
! 290: static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET };
! 291: static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET };
! 292:
! 293: /*
! 294: * Process a received ICMP message.
! 295: */
! 296: void
! 297: icmp_input(struct mbuf *m, ...)
! 298: {
! 299: struct icmp *icp;
! 300: struct ip *ip = mtod(m, struct ip *);
! 301: int icmplen;
! 302: int i;
! 303: struct in_ifaddr *ia;
! 304: void *(*ctlfunc)(int, struct sockaddr *, void *);
! 305: int code;
! 306: extern u_char ip_protox[];
! 307: int hlen;
! 308: va_list ap;
! 309: struct rtentry *rt;
! 310:
! 311: va_start(ap, m);
! 312: hlen = va_arg(ap, int);
! 313: va_end(ap);
! 314:
! 315: /*
! 316: * Locate icmp structure in mbuf, and check
! 317: * that not corrupted and of at least minimum length.
! 318: */
! 319: icmplen = ntohs(ip->ip_len) - hlen;
! 320: #ifdef ICMPPRINTFS
! 321: if (icmpprintfs) {
! 322: char buf[4 * sizeof("123")];
! 323:
! 324: strlcpy(buf, inet_ntoa(ip->ip_dst), sizeof buf);
! 325: printf("icmp_input from %s to %s, len %d\n",
! 326: inet_ntoa(ip->ip_src), buf, icmplen);
! 327: }
! 328: #endif
! 329: if (icmplen < ICMP_MINLEN) {
! 330: icmpstat.icps_tooshort++;
! 331: goto freeit;
! 332: }
! 333: i = hlen + min(icmplen, ICMP_ADVLENMIN);
! 334: if (m->m_len < i && (m = m_pullup(m, i)) == NULL) {
! 335: icmpstat.icps_tooshort++;
! 336: return;
! 337: }
! 338: ip = mtod(m, struct ip *);
! 339: m->m_len -= hlen;
! 340: m->m_data += hlen;
! 341: icp = mtod(m, struct icmp *);
! 342: if (in_cksum(m, icmplen)) {
! 343: icmpstat.icps_checksum++;
! 344: goto freeit;
! 345: }
! 346: m->m_len += hlen;
! 347: m->m_data -= hlen;
! 348:
! 349: #ifdef ICMPPRINTFS
! 350: /*
! 351: * Message type specific processing.
! 352: */
! 353: if (icmpprintfs)
! 354: printf("icmp_input, type %d code %d\n", icp->icmp_type,
! 355: icp->icmp_code);
! 356: #endif
! 357: if (icp->icmp_type > ICMP_MAXTYPE)
! 358: goto raw;
! 359: icmpstat.icps_inhist[icp->icmp_type]++;
! 360: code = icp->icmp_code;
! 361: switch (icp->icmp_type) {
! 362:
! 363: case ICMP_UNREACH:
! 364: switch (code) {
! 365: case ICMP_UNREACH_NET:
! 366: case ICMP_UNREACH_HOST:
! 367: case ICMP_UNREACH_PROTOCOL:
! 368: case ICMP_UNREACH_PORT:
! 369: case ICMP_UNREACH_SRCFAIL:
! 370: code += PRC_UNREACH_NET;
! 371: break;
! 372:
! 373: case ICMP_UNREACH_NEEDFRAG:
! 374: code = PRC_MSGSIZE;
! 375: break;
! 376:
! 377: case ICMP_UNREACH_NET_UNKNOWN:
! 378: case ICMP_UNREACH_NET_PROHIB:
! 379: case ICMP_UNREACH_TOSNET:
! 380: code = PRC_UNREACH_NET;
! 381: break;
! 382:
! 383: case ICMP_UNREACH_HOST_UNKNOWN:
! 384: case ICMP_UNREACH_ISOLATED:
! 385: case ICMP_UNREACH_HOST_PROHIB:
! 386: case ICMP_UNREACH_TOSHOST:
! 387: case ICMP_UNREACH_FILTER_PROHIB:
! 388: case ICMP_UNREACH_HOST_PRECEDENCE:
! 389: case ICMP_UNREACH_PRECEDENCE_CUTOFF:
! 390: code = PRC_UNREACH_HOST;
! 391: break;
! 392:
! 393: default:
! 394: goto badcode;
! 395: }
! 396: goto deliver;
! 397:
! 398: case ICMP_TIMXCEED:
! 399: if (code > 1)
! 400: goto badcode;
! 401: code += PRC_TIMXCEED_INTRANS;
! 402: goto deliver;
! 403:
! 404: case ICMP_PARAMPROB:
! 405: if (code > 1)
! 406: goto badcode;
! 407: code = PRC_PARAMPROB;
! 408: goto deliver;
! 409:
! 410: case ICMP_SOURCEQUENCH:
! 411: if (code)
! 412: goto badcode;
! 413: code = PRC_QUENCH;
! 414: deliver:
! 415: /* Free packet atttributes */
! 416: if (m->m_flags & M_PKTHDR)
! 417: m_tag_delete_chain(m);
! 418:
! 419: /*
! 420: * Problem with datagram; advise higher level routines.
! 421: */
! 422: if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
! 423: icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
! 424: icmpstat.icps_badlen++;
! 425: goto freeit;
! 426: }
! 427: if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr))
! 428: goto badcode;
! 429: #ifdef INET6
! 430: /* Get more contiguous data for a v6 in v4 ICMP message. */
! 431: if (icp->icmp_ip.ip_p == IPPROTO_IPV6) {
! 432: if (icmplen < ICMP_V6ADVLENMIN ||
! 433: icmplen < ICMP_V6ADVLEN(icp)) {
! 434: icmpstat.icps_badlen++;
! 435: goto freeit;
! 436: } else {
! 437: if ((m = m_pullup(m, (ip->ip_hl << 2) +
! 438: ICMP_V6ADVLEN(icp))) == NULL) {
! 439: icmpstat.icps_tooshort++;
! 440: return;
! 441: }
! 442: ip = mtod(m, struct ip *);
! 443: icp = (struct icmp *)
! 444: (m->m_data + (ip->ip_hl << 2));
! 445: }
! 446: }
! 447: #endif /* INET6 */
! 448: #ifdef ICMPPRINTFS
! 449: if (icmpprintfs)
! 450: printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
! 451: #endif
! 452: icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
! 453: #if NCARP > 0
! 454: if (m->m_pkthdr.rcvif->if_type == IFT_CARP &&
! 455: m->m_pkthdr.rcvif->if_flags & IFF_LINK0 &&
! 456: carp_lsdrop(m, AF_INET, &icmpsrc.sin_addr.s_addr,
! 457: &ip->ip_dst.s_addr))
! 458: goto freeit;
! 459: #endif
! 460: /*
! 461: * XXX if the packet contains [IPv4 AH TCP], we can't make a
! 462: * notification to TCP layer.
! 463: */
! 464: ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
! 465: if (ctlfunc)
! 466: (*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip);
! 467: break;
! 468:
! 469: badcode:
! 470: icmpstat.icps_badcode++;
! 471: break;
! 472:
! 473: case ICMP_ECHO:
! 474: if (!icmpbmcastecho &&
! 475: (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
! 476: icmpstat.icps_bmcastecho++;
! 477: break;
! 478: }
! 479: icp->icmp_type = ICMP_ECHOREPLY;
! 480: goto reflect;
! 481:
! 482: case ICMP_TSTAMP:
! 483: if (icmptstamprepl == 0)
! 484: break;
! 485:
! 486: if (!icmpbmcastecho &&
! 487: (m->m_flags & (M_MCAST | M_BCAST)) != 0) {
! 488: icmpstat.icps_bmcastecho++;
! 489: break;
! 490: }
! 491: if (icmplen < ICMP_TSLEN) {
! 492: icmpstat.icps_badlen++;
! 493: break;
! 494: }
! 495: icp->icmp_type = ICMP_TSTAMPREPLY;
! 496: icp->icmp_rtime = iptime();
! 497: icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
! 498: goto reflect;
! 499:
! 500: case ICMP_MASKREQ:
! 501: if (icmpmaskrepl == 0)
! 502: break;
! 503: /*
! 504: * We are not able to respond with all ones broadcast
! 505: * unless we receive it over a point-to-point interface.
! 506: */
! 507: if (icmplen < ICMP_MASKLEN) {
! 508: icmpstat.icps_badlen++;
! 509: break;
! 510: }
! 511: if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
! 512: ip->ip_dst.s_addr == INADDR_ANY)
! 513: icmpdst.sin_addr = ip->ip_src;
! 514: else
! 515: icmpdst.sin_addr = ip->ip_dst;
! 516: if (m->m_pkthdr.rcvif == NULL)
! 517: break;
! 518: ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst),
! 519: m->m_pkthdr.rcvif));
! 520: if (ia == 0)
! 521: break;
! 522: icp->icmp_type = ICMP_MASKREPLY;
! 523: icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
! 524: if (ip->ip_src.s_addr == 0) {
! 525: if (ia->ia_ifp->if_flags & IFF_BROADCAST)
! 526: ip->ip_src = ia->ia_broadaddr.sin_addr;
! 527: else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
! 528: ip->ip_src = ia->ia_dstaddr.sin_addr;
! 529: }
! 530: reflect:
! 531: #if NCARP > 0
! 532: if (m->m_pkthdr.rcvif->if_type == IFT_CARP &&
! 533: m->m_pkthdr.rcvif->if_flags & IFF_LINK0 &&
! 534: carp_lsdrop(m, AF_INET, &ip->ip_src.s_addr,
! 535: &ip->ip_dst.s_addr))
! 536: goto freeit;
! 537: #endif
! 538: /* Free packet atttributes */
! 539: if (m->m_flags & M_PKTHDR)
! 540: m_tag_delete_chain(m);
! 541:
! 542: icmpstat.icps_reflect++;
! 543: icmpstat.icps_outhist[icp->icmp_type]++;
! 544: icmp_reflect(m);
! 545: return;
! 546:
! 547: case ICMP_REDIRECT:
! 548: /* Free packet atttributes */
! 549: if (m->m_flags & M_PKTHDR)
! 550: m_tag_delete_chain(m);
! 551: if (icmp_rediraccept == 0)
! 552: goto freeit;
! 553: if (code > 3)
! 554: goto badcode;
! 555: if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
! 556: icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
! 557: icmpstat.icps_badlen++;
! 558: break;
! 559: }
! 560: /*
! 561: * Short circuit routing redirects to force
! 562: * immediate change in the kernel's routing
! 563: * tables. The message is also handed to anyone
! 564: * listening on a raw socket (e.g. the routing
! 565: * daemon for use in updating its tables).
! 566: */
! 567: icmpgw.sin_addr = ip->ip_src;
! 568: icmpdst.sin_addr = icp->icmp_gwaddr;
! 569: #ifdef ICMPPRINTFS
! 570: if (icmpprintfs) {
! 571: char buf[4 * sizeof("123")];
! 572: strlcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst),
! 573: sizeof buf);
! 574:
! 575: printf("redirect dst %s to %s\n",
! 576: buf, inet_ntoa(icp->icmp_gwaddr));
! 577: }
! 578: #endif
! 579: icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
! 580: #if NCARP > 0
! 581: if (m->m_pkthdr.rcvif->if_type == IFT_CARP &&
! 582: m->m_pkthdr.rcvif->if_flags & IFF_LINK0 &&
! 583: carp_lsdrop(m, AF_INET, &icmpsrc.sin_addr.s_addr,
! 584: &ip->ip_dst.s_addr))
! 585: goto freeit;
! 586: #endif
! 587: rt = NULL;
! 588: rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst),
! 589: (struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
! 590: sintosa(&icmpgw), (struct rtentry **)&rt);
! 591: if (rt != NULL && icmp_redirtimeout != 0) {
! 592: (void)rt_timer_add(rt, icmp_redirect_timeout,
! 593: icmp_redirect_timeout_q);
! 594: }
! 595: if (rt != NULL)
! 596: rtfree(rt);
! 597: pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc));
! 598: break;
! 599:
! 600: /*
! 601: * No kernel processing for the following;
! 602: * just fall through to send to raw listener.
! 603: */
! 604: case ICMP_ECHOREPLY:
! 605: case ICMP_ROUTERADVERT:
! 606: case ICMP_ROUTERSOLICIT:
! 607: case ICMP_TSTAMPREPLY:
! 608: case ICMP_IREQREPLY:
! 609: case ICMP_MASKREPLY:
! 610: case ICMP_TRACEROUTE:
! 611: case ICMP_DATACONVERR:
! 612: case ICMP_MOBILE_REDIRECT:
! 613: case ICMP_IPV6_WHEREAREYOU:
! 614: case ICMP_IPV6_IAMHERE:
! 615: case ICMP_MOBILE_REGREQUEST:
! 616: case ICMP_MOBILE_REGREPLY:
! 617: case ICMP_PHOTURIS:
! 618: default:
! 619: break;
! 620: }
! 621:
! 622: raw:
! 623: rip_input(m);
! 624: return;
! 625:
! 626: freeit:
! 627: m_freem(m);
! 628: }
! 629:
! 630: /*
! 631: * Reflect the ip packet back to the source
! 632: */
! 633: void
! 634: icmp_reflect(struct mbuf *m)
! 635: {
! 636: struct ip *ip = mtod(m, struct ip *);
! 637: struct in_ifaddr *ia;
! 638: struct in_addr t;
! 639: struct mbuf *opts = 0;
! 640: int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
! 641:
! 642: if (!in_canforward(ip->ip_src) &&
! 643: ((ip->ip_src.s_addr & IN_CLASSA_NET) !=
! 644: htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
! 645: m_freem(m); /* Bad return address */
! 646: goto done; /* ip_output() will check for broadcast */
! 647: }
! 648: t = ip->ip_dst;
! 649: ip->ip_dst = ip->ip_src;
! 650: /*
! 651: * If the incoming packet was addressed directly to us,
! 652: * use dst as the src for the reply. For broadcast, use
! 653: * the address which corresponds to the incoming interface.
! 654: */
! 655: TAILQ_FOREACH(ia, &in_ifaddr, ia_list) {
! 656: if (t.s_addr == ia->ia_addr.sin_addr.s_addr)
! 657: break;
! 658: if ((ia->ia_ifp->if_flags & IFF_BROADCAST) &&
! 659: t.s_addr == ia->ia_broadaddr.sin_addr.s_addr)
! 660: break;
! 661: }
! 662: /*
! 663: * The following happens if the packet was not addressed to us.
! 664: * Use the new source address and do a route lookup. If it fails
! 665: * drop the packet as there is no path to the host.
! 666: */
! 667: if (ia == (struct in_ifaddr *)0) {
! 668: struct sockaddr_in *dst;
! 669: struct route ro;
! 670:
! 671: bzero((caddr_t) &ro, sizeof(ro));
! 672: dst = satosin(&ro.ro_dst);
! 673: dst->sin_family = AF_INET;
! 674: dst->sin_len = sizeof(*dst);
! 675: dst->sin_addr = ip->ip_src;
! 676:
! 677: rtalloc(&ro);
! 678: if (ro.ro_rt == 0) {
! 679: ipstat.ips_noroute++;
! 680: m_freem(m);
! 681: goto done;
! 682: }
! 683:
! 684: ia = ifatoia(ro.ro_rt->rt_ifa);
! 685: ro.ro_rt->rt_use++;
! 686: RTFREE(ro.ro_rt);
! 687: }
! 688:
! 689: t = ia->ia_addr.sin_addr;
! 690: ip->ip_src = t;
! 691: ip->ip_ttl = MAXTTL;
! 692:
! 693: if (optlen > 0) {
! 694: u_char *cp;
! 695: int opt, cnt;
! 696: u_int len;
! 697:
! 698: /*
! 699: * Retrieve any source routing from the incoming packet;
! 700: * add on any record-route or timestamp options.
! 701: */
! 702: cp = (u_char *) (ip + 1);
! 703: if ((opts = ip_srcroute()) == 0 &&
! 704: (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) {
! 705: opts->m_len = sizeof(struct in_addr);
! 706: mtod(opts, struct in_addr *)->s_addr = 0;
! 707: }
! 708: if (opts) {
! 709: #ifdef ICMPPRINTFS
! 710: if (icmpprintfs)
! 711: printf("icmp_reflect optlen %d rt %d => ",
! 712: optlen, opts->m_len);
! 713: #endif
! 714: for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
! 715: opt = cp[IPOPT_OPTVAL];
! 716: if (opt == IPOPT_EOL)
! 717: break;
! 718: if (opt == IPOPT_NOP)
! 719: len = 1;
! 720: else {
! 721: if (cnt < IPOPT_OLEN + sizeof(*cp))
! 722: break;
! 723: len = cp[IPOPT_OLEN];
! 724: if (len < IPOPT_OLEN + sizeof(*cp) ||
! 725: len > cnt)
! 726: break;
! 727: }
! 728: /*
! 729: * Should check for overflow, but it
! 730: * "can't happen"
! 731: */
! 732: if (opt == IPOPT_RR || opt == IPOPT_TS ||
! 733: opt == IPOPT_SECURITY) {
! 734: bcopy((caddr_t)cp,
! 735: mtod(opts, caddr_t) + opts->m_len,
! 736: len);
! 737: opts->m_len += len;
! 738: }
! 739: }
! 740: /* Terminate & pad, if necessary */
! 741: if ((cnt = opts->m_len % 4) != 0)
! 742: for (; cnt < 4; cnt++) {
! 743: *(mtod(opts, caddr_t) + opts->m_len) =
! 744: IPOPT_EOL;
! 745: opts->m_len++;
! 746: }
! 747: #ifdef ICMPPRINTFS
! 748: if (icmpprintfs)
! 749: printf("%d\n", opts->m_len);
! 750: #endif
! 751: }
! 752: /*
! 753: * Now strip out original options by copying rest of first
! 754: * mbuf's data back, and adjust the IP length.
! 755: */
! 756: ip->ip_len = htons(ntohs(ip->ip_len) - optlen);
! 757: ip->ip_hl = sizeof(struct ip) >> 2;
! 758: m->m_len -= optlen;
! 759: if (m->m_flags & M_PKTHDR)
! 760: m->m_pkthdr.len -= optlen;
! 761: optlen += sizeof(struct ip);
! 762: bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
! 763: (unsigned)(m->m_len - sizeof(struct ip)));
! 764: }
! 765: m->m_flags &= ~(M_BCAST|M_MCAST);
! 766: icmp_send(m, opts);
! 767: done:
! 768: if (opts)
! 769: (void)m_free(opts);
! 770: }
! 771:
! 772: /*
! 773: * Send an icmp packet back to the ip level,
! 774: * after supplying a checksum.
! 775: */
! 776: void
! 777: icmp_send(struct mbuf *m, struct mbuf *opts)
! 778: {
! 779: struct ip *ip = mtod(m, struct ip *);
! 780: int hlen;
! 781: struct icmp *icp;
! 782:
! 783: hlen = ip->ip_hl << 2;
! 784: m->m_data += hlen;
! 785: m->m_len -= hlen;
! 786: icp = mtod(m, struct icmp *);
! 787: icp->icmp_cksum = 0;
! 788: icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
! 789: m->m_data -= hlen;
! 790: m->m_len += hlen;
! 791: #ifdef ICMPPRINTFS
! 792: if (icmpprintfs) {
! 793: char buf[4 * sizeof("123")];
! 794:
! 795: strlcpy(buf, inet_ntoa(ip->ip_dst), sizeof buf);
! 796: printf("icmp_send dst %s src %s\n",
! 797: buf, inet_ntoa(ip->ip_src));
! 798: }
! 799: #endif
! 800: (void)ip_output(m, opts, (void *)NULL, 0, (void *)NULL, (void *)NULL);
! 801: }
! 802:
! 803: n_time
! 804: iptime(void)
! 805: {
! 806: struct timeval atv;
! 807: u_long t;
! 808:
! 809: microtime(&atv);
! 810: t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
! 811: return (htonl(t));
! 812: }
! 813:
! 814: int
! 815: icmp_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
! 816: size_t newlen)
! 817: {
! 818:
! 819: /* All sysctl names at this level are terminal. */
! 820: if (namelen != 1)
! 821: return (ENOTDIR);
! 822:
! 823: switch (name[0]) {
! 824: case ICMPCTL_REDIRTIMEOUT: {
! 825: int error;
! 826:
! 827: error = sysctl_int(oldp, oldlenp, newp, newlen,
! 828: &icmp_redirtimeout);
! 829: if (icmp_redirect_timeout_q != NULL) {
! 830: if (icmp_redirtimeout == 0) {
! 831: rt_timer_queue_destroy(icmp_redirect_timeout_q,
! 832: TRUE);
! 833: icmp_redirect_timeout_q = NULL;
! 834: } else
! 835: rt_timer_queue_change(icmp_redirect_timeout_q,
! 836: icmp_redirtimeout);
! 837: } else if (icmp_redirtimeout > 0) {
! 838: icmp_redirect_timeout_q =
! 839: rt_timer_queue_create(icmp_redirtimeout);
! 840: }
! 841: return (error);
! 842:
! 843: break;
! 844: }
! 845: default:
! 846: if (name[0] < ICMPCTL_MAXID)
! 847: return (sysctl_int_arr(icmpctl_vars, name, namelen,
! 848: oldp, oldlenp, newp, newlen));
! 849: return (ENOPROTOOPT);
! 850: }
! 851: /* NOTREACHED */
! 852: }
! 853:
! 854:
! 855: /* XXX only handles table 0 right now */
! 856: struct rtentry *
! 857: icmp_mtudisc_clone(struct sockaddr *dst)
! 858: {
! 859: struct rtentry *rt;
! 860: int error;
! 861:
! 862: rt = rtalloc1(dst, 1, 0);
! 863: if (rt == 0)
! 864: return (NULL);
! 865:
! 866: /* If we didn't get a host route, allocate one */
! 867:
! 868: if ((rt->rt_flags & RTF_HOST) == 0) {
! 869: struct rtentry *nrt;
! 870:
! 871: error = rtrequest((int) RTM_ADD, dst,
! 872: (struct sockaddr *) rt->rt_gateway,
! 873: (struct sockaddr *) 0,
! 874: RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt, 0);
! 875: if (error) {
! 876: rtfree(rt);
! 877: return (NULL);
! 878: }
! 879: nrt->rt_rmx = rt->rt_rmx;
! 880: rtfree(rt);
! 881: rt = nrt;
! 882: }
! 883: error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q);
! 884: if (error) {
! 885: rtfree(rt);
! 886: return (NULL);
! 887: }
! 888:
! 889: return (rt);
! 890: }
! 891:
! 892: void
! 893: icmp_mtudisc(struct icmp *icp)
! 894: {
! 895: struct rtentry *rt;
! 896: struct sockaddr *dst = sintosa(&icmpsrc);
! 897: u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */
! 898:
! 899: /* Table of common MTUs: */
! 900:
! 901: static u_short mtu_table[] = {
! 902: 65535, 65280, 32000, 17914, 9180, 8166,
! 903: 4352, 2002, 1492, 1006, 508, 296, 68, 0
! 904: };
! 905:
! 906: rt = icmp_mtudisc_clone(dst);
! 907: if (rt == 0)
! 908: return;
! 909:
! 910: if (mtu == 0) {
! 911: int i = 0;
! 912:
! 913: mtu = ntohs(icp->icmp_ip.ip_len);
! 914: /* Some 4.2BSD-based routers incorrectly adjust the ip_len */
! 915: if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0)
! 916: mtu -= (icp->icmp_ip.ip_hl << 2);
! 917:
! 918: /* If we still can't guess a value, try the route */
! 919:
! 920: if (mtu == 0) {
! 921: mtu = rt->rt_rmx.rmx_mtu;
! 922:
! 923: /* If no route mtu, default to the interface mtu */
! 924:
! 925: if (mtu == 0)
! 926: mtu = rt->rt_ifp->if_mtu;
! 927: }
! 928:
! 929: for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++)
! 930: if (mtu > mtu_table[i]) {
! 931: mtu = mtu_table[i];
! 932: break;
! 933: }
! 934: }
! 935:
! 936: /*
! 937: * XXX: RTV_MTU is overloaded, since the admin can set it
! 938: * to turn off PMTU for a route, and the kernel can
! 939: * set it to indicate a serious problem with PMTU
! 940: * on a route. We should be using a separate flag
! 941: * for the kernel to indicate this.
! 942: */
! 943:
! 944: if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
! 945: if (mtu < 296 || mtu > rt->rt_ifp->if_mtu)
! 946: rt->rt_rmx.rmx_locks |= RTV_MTU;
! 947: else if (rt->rt_rmx.rmx_mtu > mtu ||
! 948: rt->rt_rmx.rmx_mtu == 0)
! 949: rt->rt_rmx.rmx_mtu = mtu;
! 950: }
! 951:
! 952: rtfree(rt);
! 953: }
! 954:
! 955: /* XXX only handles table 0 right now */
! 956: void
! 957: icmp_mtudisc_timeout(struct rtentry *rt, struct rttimer *r)
! 958: {
! 959: if (rt == NULL)
! 960: panic("icmp_mtudisc_timeout: bad route to timeout");
! 961: if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
! 962: (RTF_DYNAMIC | RTF_HOST)) {
! 963: void *(*ctlfunc)(int, struct sockaddr *, void *);
! 964: extern u_char ip_protox[];
! 965: struct sockaddr_in sa;
! 966:
! 967: sa = *(struct sockaddr_in *)rt_key(rt);
! 968: rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
! 969: rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0, 0);
! 970:
! 971: /* Notify TCP layer of increased Path MTU estimate */
! 972: ctlfunc = inetsw[ip_protox[IPPROTO_TCP]].pr_ctlinput;
! 973: if (ctlfunc)
! 974: (*ctlfunc)(PRC_MTUINC,(struct sockaddr *)&sa, NULL);
! 975: } else
! 976: if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0)
! 977: rt->rt_rmx.rmx_mtu = 0;
! 978: }
! 979:
! 980: /*
! 981: * Perform rate limit check.
! 982: * Returns 0 if it is okay to send the icmp packet.
! 983: * Returns 1 if the router SHOULD NOT send this icmp packet due to rate
! 984: * limitation.
! 985: *
! 986: * XXX per-destination/type check necessary?
! 987: */
! 988: int
! 989: icmp_ratelimit(const struct in_addr *dst, const int type, const int code)
! 990: {
! 991:
! 992: /* PPS limit */
! 993: if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count,
! 994: icmperrppslim))
! 995: return 1;
! 996:
! 997: /*okay to send*/
! 998: return 0;
! 999: }
! 1000:
! 1001: /* XXX only handles table 0 right now */
! 1002: void
! 1003: icmp_redirect_timeout(struct rtentry *rt, struct rttimer *r)
! 1004: {
! 1005: if (rt == NULL)
! 1006: panic("icmp_redirect_timeout: bad route to timeout");
! 1007: if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
! 1008: (RTF_DYNAMIC | RTF_HOST)) {
! 1009: rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
! 1010: rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0, 0);
! 1011: }
! 1012: }
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