Home | History | Annotate | Download | only in tcpdump
      1 /*
      2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that: (1) source code distributions
      7  * retain the above copyright notice and this paragraph in its entirety, (2)
      8  * distributions including binary code include the above copyright notice and
      9  * this paragraph in its entirety in the documentation or other materials
     10  * provided with the distribution, and (3) all advertising materials mentioning
     11  * features or use of this software display the following acknowledgement:
     12  * ``This product includes software developed by the University of California,
     13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
     14  * the University nor the names of its contributors may be used to endorse
     15  * or promote products derived from this software without specific prior
     16  * written permission.
     17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
     18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
     19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
     20  */
     21 
     22 /* \summary: Domain Name System (DNS) printer */
     23 
     24 #ifdef HAVE_CONFIG_H
     25 #include "config.h"
     26 #endif
     27 
     28 #include <netdissect-stdinc.h>
     29 
     30 #include "nameser.h"
     31 
     32 #include <string.h>
     33 
     34 #include "netdissect.h"
     35 #include "addrtoname.h"
     36 #include "addrtostr.h"
     37 #include "extract.h"
     38 
     39 static const char *ns_ops[] = {
     40 	"", " inv_q", " stat", " op3", " notify", " update", " op6", " op7",
     41 	" op8", " updateA", " updateD", " updateDA",
     42 	" updateM", " updateMA", " zoneInit", " zoneRef",
     43 };
     44 
     45 static const char *ns_resp[] = {
     46 	"", " FormErr", " ServFail", " NXDomain",
     47 	" NotImp", " Refused", " YXDomain", " YXRRSet",
     48 	" NXRRSet", " NotAuth", " NotZone", " Resp11",
     49 	" Resp12", " Resp13", " Resp14", " NoChange",
     50 };
     51 
     52 /* skip over a domain name */
     53 static const u_char *
     54 ns_nskip(netdissect_options *ndo,
     55          register const u_char *cp)
     56 {
     57 	register u_char i;
     58 
     59 	if (!ND_TTEST2(*cp, 1))
     60 		return (NULL);
     61 	i = *cp++;
     62 	while (i) {
     63 		if ((i & INDIR_MASK) == INDIR_MASK)
     64 			return (cp + 1);
     65 		if ((i & INDIR_MASK) == EDNS0_MASK) {
     66 			int bitlen, bytelen;
     67 
     68 			if ((i & ~INDIR_MASK) != EDNS0_ELT_BITLABEL)
     69 				return(NULL); /* unknown ELT */
     70 			if (!ND_TTEST2(*cp, 1))
     71 				return (NULL);
     72 			if ((bitlen = *cp++) == 0)
     73 				bitlen = 256;
     74 			bytelen = (bitlen + 7) / 8;
     75 			cp += bytelen;
     76 		} else
     77 			cp += i;
     78 		if (!ND_TTEST2(*cp, 1))
     79 			return (NULL);
     80 		i = *cp++;
     81 	}
     82 	return (cp);
     83 }
     84 
     85 /* print a <domain-name> */
     86 static const u_char *
     87 blabel_print(netdissect_options *ndo,
     88              const u_char *cp)
     89 {
     90 	int bitlen, slen, b;
     91 	const u_char *bitp, *lim;
     92 	char tc;
     93 
     94 	if (!ND_TTEST2(*cp, 1))
     95 		return(NULL);
     96 	if ((bitlen = *cp) == 0)
     97 		bitlen = 256;
     98 	slen = (bitlen + 3) / 4;
     99 	lim = cp + 1 + slen;
    100 
    101 	/* print the bit string as a hex string */
    102 	ND_PRINT((ndo, "\\[x"));
    103 	for (bitp = cp + 1, b = bitlen; bitp < lim && b > 7; b -= 8, bitp++) {
    104 		ND_TCHECK(*bitp);
    105 		ND_PRINT((ndo, "%02x", *bitp));
    106 	}
    107 	if (b > 4) {
    108 		ND_TCHECK(*bitp);
    109 		tc = *bitp++;
    110 		ND_PRINT((ndo, "%02x", tc & (0xff << (8 - b))));
    111 	} else if (b > 0) {
    112 		ND_TCHECK(*bitp);
    113 		tc = *bitp++;
    114 		ND_PRINT((ndo, "%1x", ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
    115 	}
    116 	ND_PRINT((ndo, "/%d]", bitlen));
    117 	return lim;
    118 trunc:
    119 	ND_PRINT((ndo, ".../%d]", bitlen));
    120 	return NULL;
    121 }
    122 
    123 static int
    124 labellen(netdissect_options *ndo,
    125          const u_char *cp)
    126 {
    127 	register u_int i;
    128 
    129 	if (!ND_TTEST2(*cp, 1))
    130 		return(-1);
    131 	i = *cp;
    132 	if ((i & INDIR_MASK) == EDNS0_MASK) {
    133 		int bitlen, elt;
    134 		if ((elt = (i & ~INDIR_MASK)) != EDNS0_ELT_BITLABEL) {
    135 			ND_PRINT((ndo, "<ELT %d>", elt));
    136 			return(-1);
    137 		}
    138 		if (!ND_TTEST2(*(cp + 1), 1))
    139 			return(-1);
    140 		if ((bitlen = *(cp + 1)) == 0)
    141 			bitlen = 256;
    142 		return(((bitlen + 7) / 8) + 1);
    143 	} else
    144 		return(i);
    145 }
    146 
    147 const u_char *
    148 ns_nprint(netdissect_options *ndo,
    149           register const u_char *cp, register const u_char *bp)
    150 {
    151 	register u_int i, l;
    152 	register const u_char *rp = NULL;
    153 	register int compress = 0;
    154 	int elt;
    155 	u_int offset, max_offset;
    156 
    157 	if ((l = labellen(ndo, cp)) == (u_int)-1)
    158 		return(NULL);
    159 	if (!ND_TTEST2(*cp, 1))
    160 		return(NULL);
    161 	max_offset = (u_int)(cp - bp);
    162 	if (((i = *cp++) & INDIR_MASK) != INDIR_MASK) {
    163 		compress = 0;
    164 		rp = cp + l;
    165 	}
    166 
    167 	if (i != 0)
    168 		while (i && cp < ndo->ndo_snapend) {
    169 			if ((i & INDIR_MASK) == INDIR_MASK) {
    170 				if (!compress) {
    171 					rp = cp + 1;
    172 					compress = 1;
    173 				}
    174 				if (!ND_TTEST2(*cp, 1))
    175 					return(NULL);
    176 				offset = (((i << 8) | *cp) & 0x3fff);
    177 				/*
    178 				 * This must move backwards in the packet.
    179 				 * No RFC explicitly says that, but BIND's
    180 				 * name decompression code requires it,
    181 				 * as a way of preventing infinite loops
    182 				 * and other bad behavior, and it's probably
    183 				 * what was intended (compress by pointing
    184 				 * to domain name suffixes already seen in
    185 				 * the packet).
    186 				 */
    187 				if (offset >= max_offset) {
    188 					ND_PRINT((ndo, "<BAD PTR>"));
    189 					return(NULL);
    190 				}
    191 				max_offset = offset;
    192 				cp = bp + offset;
    193 				if ((l = labellen(ndo, cp)) == (u_int)-1)
    194 					return(NULL);
    195 				if (!ND_TTEST2(*cp, 1))
    196 					return(NULL);
    197 				i = *cp++;
    198 				continue;
    199 			}
    200 			if ((i & INDIR_MASK) == EDNS0_MASK) {
    201 				elt = (i & ~INDIR_MASK);
    202 				switch(elt) {
    203 				case EDNS0_ELT_BITLABEL:
    204 					if (blabel_print(ndo, cp) == NULL)
    205 						return (NULL);
    206 					break;
    207 				default:
    208 					/* unknown ELT */
    209 					ND_PRINT((ndo, "<ELT %d>", elt));
    210 					return(NULL);
    211 				}
    212 			} else {
    213 				if (fn_printn(ndo, cp, l, ndo->ndo_snapend))
    214 					return(NULL);
    215 			}
    216 
    217 			cp += l;
    218 			ND_PRINT((ndo, "."));
    219 			if ((l = labellen(ndo, cp)) == (u_int)-1)
    220 				return(NULL);
    221 			if (!ND_TTEST2(*cp, 1))
    222 				return(NULL);
    223 			i = *cp++;
    224 			if (!compress)
    225 				rp += l + 1;
    226 		}
    227 	else
    228 		ND_PRINT((ndo, "."));
    229 	return (rp);
    230 }
    231 
    232 /* print a <character-string> */
    233 static const u_char *
    234 ns_cprint(netdissect_options *ndo,
    235           register const u_char *cp)
    236 {
    237 	register u_int i;
    238 
    239 	if (!ND_TTEST2(*cp, 1))
    240 		return (NULL);
    241 	i = *cp++;
    242 	if (fn_printn(ndo, cp, i, ndo->ndo_snapend))
    243 		return (NULL);
    244 	return (cp + i);
    245 }
    246 
    247 /* http://www.iana.org/assignments/dns-parameters */
    248 const struct tok ns_type2str[] = {
    249 	{ T_A,		"A" },			/* RFC 1035 */
    250 	{ T_NS,		"NS" },			/* RFC 1035 */
    251 	{ T_MD,		"MD" },			/* RFC 1035 */
    252 	{ T_MF,		"MF" },			/* RFC 1035 */
    253 	{ T_CNAME,	"CNAME" },		/* RFC 1035 */
    254 	{ T_SOA,	"SOA" },		/* RFC 1035 */
    255 	{ T_MB,		"MB" },			/* RFC 1035 */
    256 	{ T_MG,		"MG" },			/* RFC 1035 */
    257 	{ T_MR,		"MR" },			/* RFC 1035 */
    258 	{ T_NULL,	"NULL" },		/* RFC 1035 */
    259 	{ T_WKS,	"WKS" },		/* RFC 1035 */
    260 	{ T_PTR,	"PTR" },		/* RFC 1035 */
    261 	{ T_HINFO,	"HINFO" },		/* RFC 1035 */
    262 	{ T_MINFO,	"MINFO" },		/* RFC 1035 */
    263 	{ T_MX,		"MX" },			/* RFC 1035 */
    264 	{ T_TXT,	"TXT" },		/* RFC 1035 */
    265 	{ T_RP,		"RP" },			/* RFC 1183 */
    266 	{ T_AFSDB,	"AFSDB" },		/* RFC 1183 */
    267 	{ T_X25,	"X25" },		/* RFC 1183 */
    268 	{ T_ISDN,	"ISDN" },		/* RFC 1183 */
    269 	{ T_RT,		"RT" },			/* RFC 1183 */
    270 	{ T_NSAP,	"NSAP" },		/* RFC 1706 */
    271 	{ T_NSAP_PTR,	"NSAP_PTR" },
    272 	{ T_SIG,	"SIG" },		/* RFC 2535 */
    273 	{ T_KEY,	"KEY" },		/* RFC 2535 */
    274 	{ T_PX,		"PX" },			/* RFC 2163 */
    275 	{ T_GPOS,	"GPOS" },		/* RFC 1712 */
    276 	{ T_AAAA,	"AAAA" },		/* RFC 1886 */
    277 	{ T_LOC,	"LOC" },		/* RFC 1876 */
    278 	{ T_NXT,	"NXT" },		/* RFC 2535 */
    279 	{ T_EID,	"EID" },		/* Nimrod */
    280 	{ T_NIMLOC,	"NIMLOC" },		/* Nimrod */
    281 	{ T_SRV,	"SRV" },		/* RFC 2782 */
    282 	{ T_ATMA,	"ATMA" },		/* ATM Forum */
    283 	{ T_NAPTR,	"NAPTR" },		/* RFC 2168, RFC 2915 */
    284 	{ T_KX,		"KX" },			/* RFC 2230 */
    285 	{ T_CERT,	"CERT" },		/* RFC 2538 */
    286 	{ T_A6,		"A6" },			/* RFC 2874 */
    287 	{ T_DNAME,	"DNAME" },		/* RFC 2672 */
    288 	{ T_SINK, 	"SINK" },
    289 	{ T_OPT,	"OPT" },		/* RFC 2671 */
    290 	{ T_APL, 	"APL" },		/* RFC 3123 */
    291 	{ T_DS,		"DS" },			/* RFC 4034 */
    292 	{ T_SSHFP,	"SSHFP" },		/* RFC 4255 */
    293 	{ T_IPSECKEY,	"IPSECKEY" },		/* RFC 4025 */
    294 	{ T_RRSIG, 	"RRSIG" },		/* RFC 4034 */
    295 	{ T_NSEC,	"NSEC" },		/* RFC 4034 */
    296 	{ T_DNSKEY,	"DNSKEY" },		/* RFC 4034 */
    297 	{ T_SPF,	"SPF" },		/* RFC-schlitt-spf-classic-02.txt */
    298 	{ T_UINFO,	"UINFO" },
    299 	{ T_UID,	"UID" },
    300 	{ T_GID,	"GID" },
    301 	{ T_UNSPEC,	"UNSPEC" },
    302 	{ T_UNSPECA,	"UNSPECA" },
    303 	{ T_TKEY,	"TKEY" },		/* RFC 2930 */
    304 	{ T_TSIG,	"TSIG" },		/* RFC 2845 */
    305 	{ T_IXFR,	"IXFR" },		/* RFC 1995 */
    306 	{ T_AXFR,	"AXFR" },		/* RFC 1035 */
    307 	{ T_MAILB,	"MAILB" },		/* RFC 1035 */
    308 	{ T_MAILA,	"MAILA" },		/* RFC 1035 */
    309 	{ T_ANY,	"ANY" },
    310 	{ 0,		NULL }
    311 };
    312 
    313 const struct tok ns_class2str[] = {
    314 	{ C_IN,		"IN" },		/* Not used */
    315 	{ C_CHAOS,	"CHAOS" },
    316 	{ C_HS,		"HS" },
    317 	{ C_ANY,	"ANY" },
    318 	{ 0,		NULL }
    319 };
    320 
    321 /* print a query */
    322 static const u_char *
    323 ns_qprint(netdissect_options *ndo,
    324           register const u_char *cp, register const u_char *bp, int is_mdns)
    325 {
    326 	register const u_char *np = cp;
    327 	register u_int i, class;
    328 
    329 	cp = ns_nskip(ndo, cp);
    330 
    331 	if (cp == NULL || !ND_TTEST2(*cp, 4))
    332 		return(NULL);
    333 
    334 	/* print the qtype */
    335 	i = EXTRACT_16BITS(cp);
    336 	cp += 2;
    337 	ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", i)));
    338 	/* print the qclass (if it's not IN) */
    339 	i = EXTRACT_16BITS(cp);
    340 	cp += 2;
    341 	if (is_mdns)
    342 		class = (i & ~C_QU);
    343 	else
    344 		class = i;
    345 	if (class != C_IN)
    346 		ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class)));
    347 	if (is_mdns) {
    348 		ND_PRINT((ndo, i & C_QU ? " (QU)" : " (QM)"));
    349 	}
    350 
    351 	ND_PRINT((ndo, "? "));
    352 	cp = ns_nprint(ndo, np, bp);
    353 	return(cp ? cp + 4 : NULL);
    354 }
    355 
    356 /* print a reply */
    357 static const u_char *
    358 ns_rprint(netdissect_options *ndo,
    359           register const u_char *cp, register const u_char *bp, int is_mdns)
    360 {
    361 	register u_int i, class, opt_flags = 0;
    362 	register u_short typ, len;
    363 	register const u_char *rp;
    364 
    365 	if (ndo->ndo_vflag) {
    366 		ND_PRINT((ndo, " "));
    367 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
    368 			return NULL;
    369 	} else
    370 		cp = ns_nskip(ndo, cp);
    371 
    372 	if (cp == NULL || !ND_TTEST2(*cp, 10))
    373 		return (ndo->ndo_snapend);
    374 
    375 	/* print the type/qtype */
    376 	typ = EXTRACT_16BITS(cp);
    377 	cp += 2;
    378 	/* print the class (if it's not IN and the type isn't OPT) */
    379 	i = EXTRACT_16BITS(cp);
    380 	cp += 2;
    381 	if (is_mdns)
    382 		class = (i & ~C_CACHE_FLUSH);
    383 	else
    384 		class = i;
    385 	if (class != C_IN && typ != T_OPT)
    386 		ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class)));
    387 	if (is_mdns) {
    388 		if (i & C_CACHE_FLUSH)
    389 			ND_PRINT((ndo, " (Cache flush)"));
    390 	}
    391 
    392 	if (typ == T_OPT) {
    393 		/* get opt flags */
    394 		cp += 2;
    395 		opt_flags = EXTRACT_16BITS(cp);
    396 		/* ignore rest of ttl field */
    397 		cp += 2;
    398 	} else if (ndo->ndo_vflag > 2) {
    399 		/* print ttl */
    400 		ND_PRINT((ndo, " ["));
    401 		unsigned_relts_print(ndo, EXTRACT_32BITS(cp));
    402 		ND_PRINT((ndo, "]"));
    403 		cp += 4;
    404 	} else {
    405 		/* ignore ttl */
    406 		cp += 4;
    407 	}
    408 
    409 	len = EXTRACT_16BITS(cp);
    410 	cp += 2;
    411 
    412 	rp = cp + len;
    413 
    414 	ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", typ)));
    415 	if (rp > ndo->ndo_snapend)
    416 		return(NULL);
    417 
    418 	switch (typ) {
    419 	case T_A:
    420 		if (!ND_TTEST2(*cp, sizeof(struct in_addr)))
    421 			return(NULL);
    422 		ND_PRINT((ndo, " %s", intoa(htonl(EXTRACT_32BITS(cp)))));
    423 		break;
    424 
    425 	case T_NS:
    426 	case T_CNAME:
    427 	case T_PTR:
    428 #ifdef T_DNAME
    429 	case T_DNAME:
    430 #endif
    431 		ND_PRINT((ndo, " "));
    432 		if (ns_nprint(ndo, cp, bp) == NULL)
    433 			return(NULL);
    434 		break;
    435 
    436 	case T_SOA:
    437 		if (!ndo->ndo_vflag)
    438 			break;
    439 		ND_PRINT((ndo, " "));
    440 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
    441 			return(NULL);
    442 		ND_PRINT((ndo, " "));
    443 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
    444 			return(NULL);
    445 		if (!ND_TTEST2(*cp, 5 * 4))
    446 			return(NULL);
    447 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
    448 		cp += 4;
    449 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
    450 		cp += 4;
    451 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
    452 		cp += 4;
    453 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
    454 		cp += 4;
    455 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
    456 		cp += 4;
    457 		break;
    458 	case T_MX:
    459 		ND_PRINT((ndo, " "));
    460 		if (!ND_TTEST2(*cp, 2))
    461 			return(NULL);
    462 		if (ns_nprint(ndo, cp + 2, bp) == NULL)
    463 			return(NULL);
    464 		ND_PRINT((ndo, " %d", EXTRACT_16BITS(cp)));
    465 		break;
    466 
    467 	case T_TXT:
    468 		while (cp < rp) {
    469 			ND_PRINT((ndo, " \""));
    470 			cp = ns_cprint(ndo, cp);
    471 			if (cp == NULL)
    472 				return(NULL);
    473 			ND_PRINT((ndo, "\""));
    474 		}
    475 		break;
    476 
    477 	case T_SRV:
    478 		ND_PRINT((ndo, " "));
    479 		if (!ND_TTEST2(*cp, 6))
    480 			return(NULL);
    481 		if (ns_nprint(ndo, cp + 6, bp) == NULL)
    482 			return(NULL);
    483 		ND_PRINT((ndo, ":%d %d %d", EXTRACT_16BITS(cp + 4),
    484 			EXTRACT_16BITS(cp), EXTRACT_16BITS(cp + 2)));
    485 		break;
    486 
    487 	case T_AAAA:
    488 	    {
    489 		char ntop_buf[INET6_ADDRSTRLEN];
    490 
    491 		if (!ND_TTEST2(*cp, sizeof(struct in6_addr)))
    492 			return(NULL);
    493 		ND_PRINT((ndo, " %s",
    494 		    addrtostr6(cp, ntop_buf, sizeof(ntop_buf))));
    495 
    496 		break;
    497 	    }
    498 
    499 	case T_A6:
    500 	    {
    501 		struct in6_addr a;
    502 		int pbit, pbyte;
    503 		char ntop_buf[INET6_ADDRSTRLEN];
    504 
    505 		if (!ND_TTEST2(*cp, 1))
    506 			return(NULL);
    507 		pbit = *cp;
    508 		pbyte = (pbit & ~7) / 8;
    509 		if (pbit > 128) {
    510 			ND_PRINT((ndo, " %u(bad plen)", pbit));
    511 			break;
    512 		} else if (pbit < 128) {
    513 			if (!ND_TTEST2(*(cp + 1), sizeof(a) - pbyte))
    514 				return(NULL);
    515 			memset(&a, 0, sizeof(a));
    516 			memcpy(&a.s6_addr[pbyte], cp + 1, sizeof(a) - pbyte);
    517 			ND_PRINT((ndo, " %u %s", pbit,
    518 			    addrtostr6(&a, ntop_buf, sizeof(ntop_buf))));
    519 		}
    520 		if (pbit > 0) {
    521 			ND_PRINT((ndo, " "));
    522 			if (ns_nprint(ndo, cp + 1 + sizeof(a) - pbyte, bp) == NULL)
    523 				return(NULL);
    524 		}
    525 		break;
    526 	    }
    527 
    528 	case T_OPT:
    529 		ND_PRINT((ndo, " UDPsize=%u", class));
    530 		if (opt_flags & 0x8000)
    531 			ND_PRINT((ndo, " DO"));
    532 		break;
    533 
    534 	case T_UNSPECA:		/* One long string */
    535 		if (!ND_TTEST2(*cp, len))
    536 			return(NULL);
    537 		if (fn_printn(ndo, cp, len, ndo->ndo_snapend))
    538 			return(NULL);
    539 		break;
    540 
    541 	case T_TSIG:
    542 	    {
    543 		if (cp + len > ndo->ndo_snapend)
    544 			return(NULL);
    545 		if (!ndo->ndo_vflag)
    546 			break;
    547 		ND_PRINT((ndo, " "));
    548 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
    549 			return(NULL);
    550 		cp += 6;
    551 		if (!ND_TTEST2(*cp, 2))
    552 			return(NULL);
    553 		ND_PRINT((ndo, " fudge=%u", EXTRACT_16BITS(cp)));
    554 		cp += 2;
    555 		if (!ND_TTEST2(*cp, 2))
    556 			return(NULL);
    557 		ND_PRINT((ndo, " maclen=%u", EXTRACT_16BITS(cp)));
    558 		cp += 2 + EXTRACT_16BITS(cp);
    559 		if (!ND_TTEST2(*cp, 2))
    560 			return(NULL);
    561 		ND_PRINT((ndo, " origid=%u", EXTRACT_16BITS(cp)));
    562 		cp += 2;
    563 		if (!ND_TTEST2(*cp, 2))
    564 			return(NULL);
    565 		ND_PRINT((ndo, " error=%u", EXTRACT_16BITS(cp)));
    566 		cp += 2;
    567 		if (!ND_TTEST2(*cp, 2))
    568 			return(NULL);
    569 		ND_PRINT((ndo, " otherlen=%u", EXTRACT_16BITS(cp)));
    570 		cp += 2;
    571 	    }
    572 	}
    573 	return (rp);		/* XXX This isn't always right */
    574 }
    575 
    576 void
    577 ns_print(netdissect_options *ndo,
    578          register const u_char *bp, u_int length, int is_mdns)
    579 {
    580 	register const HEADER *np;
    581 	register int qdcount, ancount, nscount, arcount;
    582 	register const u_char *cp;
    583 	uint16_t b2;
    584 
    585 	np = (const HEADER *)bp;
    586 	ND_TCHECK(*np);
    587 	/* get the byte-order right */
    588 	qdcount = EXTRACT_16BITS(&np->qdcount);
    589 	ancount = EXTRACT_16BITS(&np->ancount);
    590 	nscount = EXTRACT_16BITS(&np->nscount);
    591 	arcount = EXTRACT_16BITS(&np->arcount);
    592 
    593 	if (DNS_QR(np)) {
    594 		/* this is a response */
    595 		ND_PRINT((ndo, "%d%s%s%s%s%s%s",
    596 			EXTRACT_16BITS(&np->id),
    597 			ns_ops[DNS_OPCODE(np)],
    598 			ns_resp[DNS_RCODE(np)],
    599 			DNS_AA(np)? "*" : "",
    600 			DNS_RA(np)? "" : "-",
    601 			DNS_TC(np)? "|" : "",
    602 			DNS_AD(np)? "$" : ""));
    603 
    604 		if (qdcount != 1)
    605 			ND_PRINT((ndo, " [%dq]", qdcount));
    606 		/* Print QUESTION section on -vv */
    607 		cp = (const u_char *)(np + 1);
    608 		while (qdcount--) {
    609 			if (qdcount < EXTRACT_16BITS(&np->qdcount) - 1)
    610 				ND_PRINT((ndo, ","));
    611 			if (ndo->ndo_vflag > 1) {
    612 				ND_PRINT((ndo, " q:"));
    613 				if ((cp = ns_qprint(ndo, cp, bp, is_mdns)) == NULL)
    614 					goto trunc;
    615 			} else {
    616 				if ((cp = ns_nskip(ndo, cp)) == NULL)
    617 					goto trunc;
    618 				cp += 4;	/* skip QTYPE and QCLASS */
    619 			}
    620 		}
    621 		ND_PRINT((ndo, " %d/%d/%d", ancount, nscount, arcount));
    622 		if (ancount--) {
    623 			if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    624 				goto trunc;
    625 			while (cp < ndo->ndo_snapend && ancount--) {
    626 				ND_PRINT((ndo, ","));
    627 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    628 					goto trunc;
    629 			}
    630 		}
    631 		if (ancount > 0)
    632 			goto trunc;
    633 		/* Print NS and AR sections on -vv */
    634 		if (ndo->ndo_vflag > 1) {
    635 			if (cp < ndo->ndo_snapend && nscount--) {
    636 				ND_PRINT((ndo, " ns:"));
    637 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    638 					goto trunc;
    639 				while (cp < ndo->ndo_snapend && nscount--) {
    640 					ND_PRINT((ndo, ","));
    641 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    642 						goto trunc;
    643 				}
    644 			}
    645 			if (nscount > 0)
    646 				goto trunc;
    647 			if (cp < ndo->ndo_snapend && arcount--) {
    648 				ND_PRINT((ndo, " ar:"));
    649 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    650 					goto trunc;
    651 				while (cp < ndo->ndo_snapend && arcount--) {
    652 					ND_PRINT((ndo, ","));
    653 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    654 						goto trunc;
    655 				}
    656 			}
    657 			if (arcount > 0)
    658 				goto trunc;
    659 		}
    660 	}
    661 	else {
    662 		/* this is a request */
    663 		ND_PRINT((ndo, "%d%s%s%s", EXTRACT_16BITS(&np->id), ns_ops[DNS_OPCODE(np)],
    664 		    DNS_RD(np) ? "+" : "",
    665 		    DNS_CD(np) ? "%" : ""));
    666 
    667 		/* any weirdness? */
    668 		b2 = EXTRACT_16BITS(((const u_short *)np)+1);
    669 		if (b2 & 0x6cf)
    670 			ND_PRINT((ndo, " [b2&3=0x%x]", b2));
    671 
    672 		if (DNS_OPCODE(np) == IQUERY) {
    673 			if (qdcount)
    674 				ND_PRINT((ndo, " [%dq]", qdcount));
    675 			if (ancount != 1)
    676 				ND_PRINT((ndo, " [%da]", ancount));
    677 		}
    678 		else {
    679 			if (ancount)
    680 				ND_PRINT((ndo, " [%da]", ancount));
    681 			if (qdcount != 1)
    682 				ND_PRINT((ndo, " [%dq]", qdcount));
    683 		}
    684 		if (nscount)
    685 			ND_PRINT((ndo, " [%dn]", nscount));
    686 		if (arcount)
    687 			ND_PRINT((ndo, " [%dau]", arcount));
    688 
    689 		cp = (const u_char *)(np + 1);
    690 		if (qdcount--) {
    691 			cp = ns_qprint(ndo, cp, (const u_char *)np, is_mdns);
    692 			if (!cp)
    693 				goto trunc;
    694 			while (cp < ndo->ndo_snapend && qdcount--) {
    695 				cp = ns_qprint(ndo, (const u_char *)cp,
    696 					       (const u_char *)np,
    697 					       is_mdns);
    698 				if (!cp)
    699 					goto trunc;
    700 			}
    701 		}
    702 		if (qdcount > 0)
    703 			goto trunc;
    704 
    705 		/* Print remaining sections on -vv */
    706 		if (ndo->ndo_vflag > 1) {
    707 			if (ancount--) {
    708 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    709 					goto trunc;
    710 				while (cp < ndo->ndo_snapend && ancount--) {
    711 					ND_PRINT((ndo, ","));
    712 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    713 						goto trunc;
    714 				}
    715 			}
    716 			if (ancount > 0)
    717 				goto trunc;
    718 			if (cp < ndo->ndo_snapend && nscount--) {
    719 				ND_PRINT((ndo, " ns:"));
    720 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    721 					goto trunc;
    722 				while (nscount-- && cp < ndo->ndo_snapend) {
    723 					ND_PRINT((ndo, ","));
    724 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    725 						goto trunc;
    726 				}
    727 			}
    728 			if (nscount > 0)
    729 				goto trunc;
    730 			if (cp < ndo->ndo_snapend && arcount--) {
    731 				ND_PRINT((ndo, " ar:"));
    732 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    733 					goto trunc;
    734 				while (cp < ndo->ndo_snapend && arcount--) {
    735 					ND_PRINT((ndo, ","));
    736 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
    737 						goto trunc;
    738 				}
    739 			}
    740 			if (arcount > 0)
    741 				goto trunc;
    742 		}
    743 	}
    744 	ND_PRINT((ndo, " (%d)", length));
    745 	return;
    746 
    747   trunc:
    748 	ND_PRINT((ndo, "[|domain]"));
    749 }
    750