print-domain.c - platform/external/tcpdump - Git at Google

 /*
  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
  *	The Regents of the University of California.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that: (1) source code distributions
  * retain the above copyright notice and this paragraph in its entirety, (2)
  * distributions including binary code include the above copyright notice and
  * this paragraph in its entirety in the documentation or other materials
  * provided with the distribution, and (3) all advertising materials mentioning
  * features or use of this software display the following acknowledgement:
  * ``This product includes software developed by the University of California,
  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  * the University nor the names of its contributors may be used to endorse
  * or promote products derived from this software without specific prior
  * written permission.
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */

 /* \summary: Domain Name System (DNS) printer */

 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif

 #include <netdissect-stdinc.h>

 #include "nameser.h"

 #include <string.h>

 #include "netdissect.h"
 #include "addrtoname.h"
 #include "addrtostr.h"
 #include "extract.h"

 static const char *ns_ops[] = {
 	"", " inv_q", " stat", " op3", " notify", " update", " op6", " op7",
 	" op8", " updateA", " updateD", " updateDA",
 	" updateM", " updateMA", " zoneInit", " zoneRef",
 };

 static const char *ns_resp[] = {
 	"", " FormErr", " ServFail", " NXDomain",
 	" NotImp", " Refused", " YXDomain", " YXRRSet",
 	" NXRRSet", " NotAuth", " NotZone", " Resp11",
 	" Resp12", " Resp13", " Resp14", " NoChange",
 };

 /* skip over a domain name */
 static const u_char *
 ns_nskip(netdissect_options *ndo,
          register const u_char *cp)
 {
 	register u_char i;

 	if (!ND_TTEST2(*cp, 1))
 		return (NULL);
 	i = *cp++;
 	while (i) {
 		if ((i & INDIR_MASK) == INDIR_MASK)
 			return (cp + 1);
 		if ((i & INDIR_MASK) == EDNS0_MASK) {
 			int bitlen, bytelen;

 			if ((i & ~INDIR_MASK) != EDNS0_ELT_BITLABEL)
 				return(NULL); /* unknown ELT */
 			if (!ND_TTEST2(*cp, 1))
 				return (NULL);
 			if ((bitlen = *cp++) == 0)
 				bitlen = 256;
 			bytelen = (bitlen + 7) / 8;
 			cp += bytelen;
 		} else
 			cp += i;
 		if (!ND_TTEST2(*cp, 1))
 			return (NULL);
 		i = *cp++;
 	}
 	return (cp);
 }

 /* print a <domain-name> */
 static const u_char *
 blabel_print(netdissect_options *ndo,
              const u_char *cp)
 {
 	int bitlen, slen, b;
 	const u_char *bitp, *lim;
 	char tc;

 	if (!ND_TTEST2(*cp, 1))
 		return(NULL);
 	if ((bitlen = *cp) == 0)
 		bitlen = 256;
 	slen = (bitlen + 3) / 4;
 	lim = cp + 1 + slen;

 	/* print the bit string as a hex string */
 	ND_PRINT((ndo, "\\[x"));
 	for (bitp = cp + 1, b = bitlen; bitp < lim && b > 7; b -= 8, bitp++) {
 		ND_TCHECK(*bitp);
 		ND_PRINT((ndo, "%02x", *bitp));
 	}
 	if (b > 4) {
 		ND_TCHECK(*bitp);
 		tc = *bitp++;
 		ND_PRINT((ndo, "%02x", tc & (0xff << (8 - b))));
 	} else if (b > 0) {
 		ND_TCHECK(*bitp);
 		tc = *bitp++;
 		ND_PRINT((ndo, "%1x", ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
 	}
 	ND_PRINT((ndo, "/%d]", bitlen));
 	return lim;
 trunc:
 	ND_PRINT((ndo, ".../%d]", bitlen));
 	return NULL;
 }

 static int
 labellen(netdissect_options *ndo,
          const u_char *cp)
 {
 	register u_int i;

 	if (!ND_TTEST2(*cp, 1))
 		return(-1);
 	i = *cp;
 	if ((i & INDIR_MASK) == EDNS0_MASK) {
 		int bitlen, elt;
 		if ((elt = (i & ~INDIR_MASK)) != EDNS0_ELT_BITLABEL) {
 			ND_PRINT((ndo, "<ELT %d>", elt));
 			return(-1);
 		}
 		if (!ND_TTEST2(*(cp + 1), 1))
 			return(-1);
 		if ((bitlen = *(cp + 1)) == 0)
 			bitlen = 256;
 		return(((bitlen + 7) / 8) + 1);
 	} else
 		return(i);
 }

 const u_char *
 ns_nprint(netdissect_options *ndo,
           register const u_char *cp, register const u_char *bp)
 {
 	register u_int i, l;
 	register const u_char *rp = NULL;
 	register int compress = 0;
 	int elt;
 	u_int offset, max_offset;

 	if ((l = labellen(ndo, cp)) == (u_int)-1)
 		return(NULL);
 	if (!ND_TTEST2(*cp, 1))
 		return(NULL);
 	max_offset = (u_int)(cp - bp);
 	if (((i = *cp++) & INDIR_MASK) != INDIR_MASK) {
 		compress = 0;
 		rp = cp + l;
 	}

 	if (i != 0)
 		while (i && cp < ndo->ndo_snapend) {
 			if ((i & INDIR_MASK) == INDIR_MASK) {
 				if (!compress) {
 					rp = cp + 1;
 					compress = 1;
 				}
 				if (!ND_TTEST2(*cp, 1))
 					return(NULL);
 				offset = (((i << 8) | *cp) & 0x3fff);
 				/*
 				 * This must move backwards in the packet.
 				 * No RFC explicitly says that, but BIND's
 				 * name decompression code requires it,
 				 * as a way of preventing infinite loops
 				 * and other bad behavior, and it's probably
 				 * what was intended (compress by pointing
 				 * to domain name suffixes already seen in
 				 * the packet).
 				 */
 				if (offset >= max_offset) {
 					ND_PRINT((ndo, "<BAD PTR>"));
 					return(NULL);
 				}
 				max_offset = offset;
 				cp = bp + offset;
 				if ((l = labellen(ndo, cp)) == (u_int)-1)
 					return(NULL);
 				if (!ND_TTEST2(*cp, 1))
 					return(NULL);
 				i = *cp++;
 				continue;
 			}
 			if ((i & INDIR_MASK) == EDNS0_MASK) {
 				elt = (i & ~INDIR_MASK);
 				switch(elt) {
 				case EDNS0_ELT_BITLABEL:
 					if (blabel_print(ndo, cp) == NULL)
 						return (NULL);
 					break;
 				default:
 					/* unknown ELT */
 					ND_PRINT((ndo, "<ELT %d>", elt));
 					return(NULL);
 				}
 			} else {
 				if (fn_printn(ndo, cp, l, ndo->ndo_snapend))
 					return(NULL);
 			}

 			cp += l;
 			ND_PRINT((ndo, "."));
 			if ((l = labellen(ndo, cp)) == (u_int)-1)
 				return(NULL);
 			if (!ND_TTEST2(*cp, 1))
 				return(NULL);
 			i = *cp++;
 			if (!compress)
 				rp += l + 1;
 		}
 	else
 		ND_PRINT((ndo, "."));
 	return (rp);
 }

 /* print a <character-string> */
 static const u_char *
 ns_cprint(netdissect_options *ndo,
           register const u_char *cp)
 {
 	register u_int i;

 	if (!ND_TTEST2(*cp, 1))
 		return (NULL);
 	i = *cp++;
 	if (fn_printn(ndo, cp, i, ndo->ndo_snapend))
 		return (NULL);
 	return (cp + i);
 }

 /* http://www.iana.org/assignments/dns-parameters */
 const struct tok ns_type2str[] = {
 	{ T_A,		"A" },			/* RFC 1035 */
 	{ T_NS,		"NS" },			/* RFC 1035 */
 	{ T_MD,		"MD" },			/* RFC 1035 */
 	{ T_MF,		"MF" },			/* RFC 1035 */
 	{ T_CNAME,	"CNAME" },		/* RFC 1035 */
 	{ T_SOA,	"SOA" },		/* RFC 1035 */
 	{ T_MB,		"MB" },			/* RFC 1035 */
 	{ T_MG,		"MG" },			/* RFC 1035 */
 	{ T_MR,		"MR" },			/* RFC 1035 */
 	{ T_NULL,	"NULL" },		/* RFC 1035 */
 	{ T_WKS,	"WKS" },		/* RFC 1035 */
 	{ T_PTR,	"PTR" },		/* RFC 1035 */
 	{ T_HINFO,	"HINFO" },		/* RFC 1035 */
 	{ T_MINFO,	"MINFO" },		/* RFC 1035 */
 	{ T_MX,		"MX" },			/* RFC 1035 */
 	{ T_TXT,	"TXT" },		/* RFC 1035 */
 	{ T_RP,		"RP" },			/* RFC 1183 */
 	{ T_AFSDB,	"AFSDB" },		/* RFC 1183 */
 	{ T_X25,	"X25" },		/* RFC 1183 */
 	{ T_ISDN,	"ISDN" },		/* RFC 1183 */
 	{ T_RT,		"RT" },			/* RFC 1183 */
 	{ T_NSAP,	"NSAP" },		/* RFC 1706 */
 	{ T_NSAP_PTR,	"NSAP_PTR" },
 	{ T_SIG,	"SIG" },		/* RFC 2535 */
 	{ T_KEY,	"KEY" },		/* RFC 2535 */
 	{ T_PX,		"PX" },			/* RFC 2163 */
 	{ T_GPOS,	"GPOS" },		/* RFC 1712 */
 	{ T_AAAA,	"AAAA" },		/* RFC 1886 */
 	{ T_LOC,	"LOC" },		/* RFC 1876 */
 	{ T_NXT,	"NXT" },		/* RFC 2535 */
 	{ T_EID,	"EID" },		/* Nimrod */
 	{ T_NIMLOC,	"NIMLOC" },		/* Nimrod */
 	{ T_SRV,	"SRV" },		/* RFC 2782 */
 	{ T_ATMA,	"ATMA" },		/* ATM Forum */
 	{ T_NAPTR,	"NAPTR" },		/* RFC 2168, RFC 2915 */
 	{ T_KX,		"KX" },			/* RFC 2230 */
 	{ T_CERT,	"CERT" },		/* RFC 2538 */
 	{ T_A6,		"A6" },			/* RFC 2874 */
 	{ T_DNAME,	"DNAME" },		/* RFC 2672 */
 	{ T_SINK, 	"SINK" },
 	{ T_OPT,	"OPT" },		/* RFC 2671 */
 	{ T_APL, 	"APL" },		/* RFC 3123 */
 	{ T_DS,		"DS" },			/* RFC 4034 */
 	{ T_SSHFP,	"SSHFP" },		/* RFC 4255 */
 	{ T_IPSECKEY,	"IPSECKEY" },		/* RFC 4025 */
 	{ T_RRSIG, 	"RRSIG" },		/* RFC 4034 */
 	{ T_NSEC,	"NSEC" },		/* RFC 4034 */
 	{ T_DNSKEY,	"DNSKEY" },		/* RFC 4034 */
 	{ T_SPF,	"SPF" },		/* RFC-schlitt-spf-classic-02.txt */
 	{ T_UINFO,	"UINFO" },
 	{ T_UID,	"UID" },
 	{ T_GID,	"GID" },
 	{ T_UNSPEC,	"UNSPEC" },
 	{ T_UNSPECA,	"UNSPECA" },
 	{ T_TKEY,	"TKEY" },		/* RFC 2930 */
 	{ T_TSIG,	"TSIG" },		/* RFC 2845 */
 	{ T_IXFR,	"IXFR" },		/* RFC 1995 */
 	{ T_AXFR,	"AXFR" },		/* RFC 1035 */
 	{ T_MAILB,	"MAILB" },		/* RFC 1035 */
 	{ T_MAILA,	"MAILA" },		/* RFC 1035 */
 	{ T_ANY,	"ANY" },
 	{ 0,		NULL }
 };

 const struct tok ns_class2str[] = {
 	{ C_IN,		"IN" },		/* Not used */
 	{ C_CHAOS,	"CHAOS" },
 	{ C_HS,		"HS" },
 	{ C_ANY,	"ANY" },
 	{ 0,		NULL }
 };

 /* print a query */
 static const u_char *
 ns_qprint(netdissect_options *ndo,
           register const u_char *cp, register const u_char *bp, int is_mdns)
 {
 	register const u_char *np = cp;
 	register u_int i, class;

 	cp = ns_nskip(ndo, cp);

 	if (cp == NULL || !ND_TTEST2(*cp, 4))
 		return(NULL);

 	/* print the qtype */
 	i = EXTRACT_16BITS(cp);
 	cp += 2;
 	ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", i)));
 	/* print the qclass (if it's not IN) */
 	i = EXTRACT_16BITS(cp);
 	cp += 2;
 	if (is_mdns)
 		class = (i & ~C_QU);
 	else
 		class = i;
 	if (class != C_IN)
 		ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class)));
 	if (is_mdns) {
 		ND_PRINT((ndo, i & C_QU ? " (QU)" : " (QM)"));
 	}

 	ND_PRINT((ndo, "? "));
 	cp = ns_nprint(ndo, np, bp);
 	return(cp ? cp + 4 : NULL);
 }

 /* print a reply */
 static const u_char *
 ns_rprint(netdissect_options *ndo,
           register const u_char *cp, register const u_char *bp, int is_mdns)
 {
 	register u_int i, class, opt_flags = 0;
 	register u_short typ, len;
 	register const u_char *rp;

 	if (ndo->ndo_vflag) {
 		ND_PRINT((ndo, " "));
 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
 			return NULL;
 	} else
 		cp = ns_nskip(ndo, cp);

 	if (cp == NULL || !ND_TTEST2(*cp, 10))
 		return (ndo->ndo_snapend);

 	/* print the type/qtype */
 	typ = EXTRACT_16BITS(cp);
 	cp += 2;
 	/* print the class (if it's not IN and the type isn't OPT) */
 	i = EXTRACT_16BITS(cp);
 	cp += 2;
 	if (is_mdns)
 		class = (i & ~C_CACHE_FLUSH);
 	else
 		class = i;
 	if (class != C_IN && typ != T_OPT)
 		ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class)));
 	if (is_mdns) {
 		if (i & C_CACHE_FLUSH)
 			ND_PRINT((ndo, " (Cache flush)"));
 	}

 	if (typ == T_OPT) {
 		/* get opt flags */
 		cp += 2;
 		opt_flags = EXTRACT_16BITS(cp);
 		/* ignore rest of ttl field */
 		cp += 2;
 	} else if (ndo->ndo_vflag > 2) {
 		/* print ttl */
 		ND_PRINT((ndo, " ["));
 		unsigned_relts_print(ndo, EXTRACT_32BITS(cp));
 		ND_PRINT((ndo, "]"));
 		cp += 4;
 	} else {
 		/* ignore ttl */
 		cp += 4;
 	}

 	len = EXTRACT_16BITS(cp);
 	cp += 2;

 	rp = cp + len;

 	ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", typ)));
 	if (rp > ndo->ndo_snapend)
 		return(NULL);

 	switch (typ) {
 	case T_A:
 		if (!ND_TTEST2(*cp, sizeof(struct in_addr)))
 			return(NULL);
 		ND_PRINT((ndo, " %s", intoa(htonl(EXTRACT_32BITS(cp)))));
 		break;

 	case T_NS:
 	case T_CNAME:
 	case T_PTR:
 #ifdef T_DNAME
 	case T_DNAME:
 #endif
 		ND_PRINT((ndo, " "));
 		if (ns_nprint(ndo, cp, bp) == NULL)
 			return(NULL);
 		break;

 	case T_SOA:
 		if (!ndo->ndo_vflag)
 			break;
 		ND_PRINT((ndo, " "));
 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
 			return(NULL);
 		ND_PRINT((ndo, " "));
 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
 			return(NULL);
 		if (!ND_TTEST2(*cp, 5 * 4))
 			return(NULL);
 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 		cp += 4;
 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 		cp += 4;
 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 		cp += 4;
 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 		cp += 4;
 		ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 		cp += 4;
 		break;
 	case T_MX:
 		ND_PRINT((ndo, " "));
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
 		if (ns_nprint(ndo, cp + 2, bp) == NULL)
 			return(NULL);
 		ND_PRINT((ndo, " %d", EXTRACT_16BITS(cp)));
 		break;

 	case T_TXT:
 		while (cp < rp) {
 			ND_PRINT((ndo, " \""));
 			cp = ns_cprint(ndo, cp);
 			if (cp == NULL)
 				return(NULL);
 			ND_PRINT((ndo, "\""));
 		}
 		break;

 	case T_SRV:
 		ND_PRINT((ndo, " "));
 		if (!ND_TTEST2(*cp, 6))
 			return(NULL);
 		if (ns_nprint(ndo, cp + 6, bp) == NULL)
 			return(NULL);
 		ND_PRINT((ndo, ":%d %d %d", EXTRACT_16BITS(cp + 4),
 			EXTRACT_16BITS(cp), EXTRACT_16BITS(cp + 2)));
 		break;

 	case T_AAAA:
 	    {
 		char ntop_buf[INET6_ADDRSTRLEN];

 		if (!ND_TTEST2(*cp, sizeof(struct in6_addr)))
 			return(NULL);
 		ND_PRINT((ndo, " %s",
 		    addrtostr6(cp, ntop_buf, sizeof(ntop_buf))));

 		break;
 	    }

 	case T_A6:
 	    {
 		struct in6_addr a;
 		int pbit, pbyte;
 		char ntop_buf[INET6_ADDRSTRLEN];

 		if (!ND_TTEST2(*cp, 1))
 			return(NULL);
 		pbit = *cp;
 		pbyte = (pbit & ~7) / 8;
 		if (pbit > 128) {
 			ND_PRINT((ndo, " %u(bad plen)", pbit));
 			break;
 		} else if (pbit < 128) {
 			if (!ND_TTEST2(*(cp + 1), sizeof(a) - pbyte))
 				return(NULL);
 			memset(&a, 0, sizeof(a));
 			memcpy(&a.s6_addr[pbyte], cp + 1, sizeof(a) - pbyte);
 			ND_PRINT((ndo, " %u %s", pbit,
 			    addrtostr6(&a, ntop_buf, sizeof(ntop_buf))));
 		}
 		if (pbit > 0) {
 			ND_PRINT((ndo, " "));
 			if (ns_nprint(ndo, cp + 1 + sizeof(a) - pbyte, bp) == NULL)
 				return(NULL);
 		}
 		break;
 	    }

 	case T_OPT:
 		ND_PRINT((ndo, " UDPsize=%u", class));
 		if (opt_flags & 0x8000)
 			ND_PRINT((ndo, " DO"));
 		break;

 	case T_UNSPECA:		/* One long string */
 		if (!ND_TTEST2(*cp, len))
 			return(NULL);
 		if (fn_printn(ndo, cp, len, ndo->ndo_snapend))
 			return(NULL);
 		break;

 	case T_TSIG:
 	    {
 		if (cp + len > ndo->ndo_snapend)
 			return(NULL);
 		if (!ndo->ndo_vflag)
 			break;
 		ND_PRINT((ndo, " "));
 		if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
 			return(NULL);
 		cp += 6;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
 		ND_PRINT((ndo, " fudge=%u", EXTRACT_16BITS(cp)));
 		cp += 2;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
 		ND_PRINT((ndo, " maclen=%u", EXTRACT_16BITS(cp)));
 		cp += 2 + EXTRACT_16BITS(cp);
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
 		ND_PRINT((ndo, " origid=%u", EXTRACT_16BITS(cp)));
 		cp += 2;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
 		ND_PRINT((ndo, " error=%u", EXTRACT_16BITS(cp)));
 		cp += 2;
 		if (!ND_TTEST2(*cp, 2))
 			return(NULL);
 		ND_PRINT((ndo, " otherlen=%u", EXTRACT_16BITS(cp)));
 		cp += 2;
 	    }
 	}
 	return (rp);		/* XXX This isn't always right */
 }

 void
 ns_print(netdissect_options *ndo,
          register const u_char *bp, u_int length, int is_mdns)
 {
 	register const HEADER *np;
 	register int qdcount, ancount, nscount, arcount;
 	register const u_char *cp;
 	uint16_t b2;

 	np = (const HEADER *)bp;
 	ND_TCHECK(*np);
 	/* get the byte-order right */
 	qdcount = EXTRACT_16BITS(&np->qdcount);
 	ancount = EXTRACT_16BITS(&np->ancount);
 	nscount = EXTRACT_16BITS(&np->nscount);
 	arcount = EXTRACT_16BITS(&np->arcount);

 	if (DNS_QR(np)) {
 		/* this is a response */
 		ND_PRINT((ndo, "%d%s%s%s%s%s%s",
 			EXTRACT_16BITS(&np->id),
 			ns_ops[DNS_OPCODE(np)],
 			ns_resp[DNS_RCODE(np)],
 			DNS_AA(np)? "*" : "",
 			DNS_RA(np)? "" : "-",
 			DNS_TC(np)? "|" : "",
 			DNS_AD(np)? "$" : ""));

 		if (qdcount != 1)
 			ND_PRINT((ndo, " [%dq]", qdcount));
 		/* Print QUESTION section on -vv */
 		cp = (const u_char *)(np + 1);
 		while (qdcount--) {
 			if (qdcount < EXTRACT_16BITS(&np->qdcount) - 1)
 				ND_PRINT((ndo, ","));
 			if (ndo->ndo_vflag > 1) {
 				ND_PRINT((ndo, " q:"));
 				if ((cp = ns_qprint(ndo, cp, bp, is_mdns)) == NULL)
 					goto trunc;
 			} else {
 				if ((cp = ns_nskip(ndo, cp)) == NULL)
 					goto trunc;
 				cp += 4;	/* skip QTYPE and QCLASS */
 			}
 		}
 		ND_PRINT((ndo, " %d/%d/%d", ancount, nscount, arcount));
 		if (ancount--) {
 			if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 				goto trunc;
 			while (cp < ndo->ndo_snapend && ancount--) {
 				ND_PRINT((ndo, ","));
 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 					goto trunc;
 			}
 		}
 		if (ancount > 0)
 			goto trunc;
 		/* Print NS and AR sections on -vv */
 		if (ndo->ndo_vflag > 1) {
 			if (cp < ndo->ndo_snapend && nscount--) {
 				ND_PRINT((ndo, " ns:"));
 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 					goto trunc;
 				while (cp < ndo->ndo_snapend && nscount--) {
 					ND_PRINT((ndo, ","));
 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 						goto trunc;
 				}
 			}
 			if (nscount > 0)
 				goto trunc;
 			if (cp < ndo->ndo_snapend && arcount--) {
 				ND_PRINT((ndo, " ar:"));
 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 					goto trunc;
 				while (cp < ndo->ndo_snapend && arcount--) {
 					ND_PRINT((ndo, ","));
 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 						goto trunc;
 				}
 			}
 			if (arcount > 0)
 				goto trunc;
 		}
 	}
 	else {
 		/* this is a request */
 		ND_PRINT((ndo, "%d%s%s%s", EXTRACT_16BITS(&np->id), ns_ops[DNS_OPCODE(np)],
 		    DNS_RD(np) ? "+" : "",
 		    DNS_CD(np) ? "%" : ""));

 		/* any weirdness? */
 		b2 = EXTRACT_16BITS(((const u_short *)np)+1);
 		if (b2 & 0x6cf)
 			ND_PRINT((ndo, " [b2&3=0x%x]", b2));

 		if (DNS_OPCODE(np) == IQUERY) {
 			if (qdcount)
 				ND_PRINT((ndo, " [%dq]", qdcount));
 			if (ancount != 1)
 				ND_PRINT((ndo, " [%da]", ancount));
 		}
 		else {
 			if (ancount)
 				ND_PRINT((ndo, " [%da]", ancount));
 			if (qdcount != 1)
 				ND_PRINT((ndo, " [%dq]", qdcount));
 		}
 		if (nscount)
 			ND_PRINT((ndo, " [%dn]", nscount));
 		if (arcount)
 			ND_PRINT((ndo, " [%dau]", arcount));

 		cp = (const u_char *)(np + 1);
 		if (qdcount--) {
 			cp = ns_qprint(ndo, cp, (const u_char *)np, is_mdns);
 			if (!cp)
 				goto trunc;
 			while (cp < ndo->ndo_snapend && qdcount--) {
 				cp = ns_qprint(ndo, (const u_char *)cp,
 					       (const u_char *)np,
 					       is_mdns);
 				if (!cp)
 					goto trunc;
 			}
 		}
 		if (qdcount > 0)
 			goto trunc;

 		/* Print remaining sections on -vv */
 		if (ndo->ndo_vflag > 1) {
 			if (ancount--) {
 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 					goto trunc;
 				while (cp < ndo->ndo_snapend && ancount--) {
 					ND_PRINT((ndo, ","));
 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 						goto trunc;
 				}
 			}
 			if (ancount > 0)
 				goto trunc;
 			if (cp < ndo->ndo_snapend && nscount--) {
 				ND_PRINT((ndo, " ns:"));
 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 					goto trunc;
 				while (nscount-- && cp < ndo->ndo_snapend) {
 					ND_PRINT((ndo, ","));
 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 						goto trunc;
 				}
 			}
 			if (nscount > 0)
 				goto trunc;
 			if (cp < ndo->ndo_snapend && arcount--) {
 				ND_PRINT((ndo, " ar:"));
 				if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 					goto trunc;
 				while (cp < ndo->ndo_snapend && arcount--) {
 					ND_PRINT((ndo, ","));
 					if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
 						goto trunc;
 				}
 			}
 			if (arcount > 0)
 				goto trunc;
 		}
 	}
 	ND_PRINT((ndo, " (%d)", length));
 	return;

   trunc:
 	ND_PRINT((ndo, "[|domain]"));
 }
	/*
	* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
	* The Regents of the University of California. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that: (1) source code distributions
	* retain the above copyright notice and this paragraph in its entirety, (2)
	* distributions including binary code include the above copyright notice and
	* this paragraph in its entirety in the documentation or other materials
	* provided with the distribution, and (3) all advertising materials mentioning
	* features or use of this software display the following acknowledgement:
	* ``This product includes software developed by the University of California,
	* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
	* the University nor the names of its contributors may be used to endorse
	* or promote products derived from this software without specific prior
	* written permission.
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
	*/

	/* \summary: Domain Name System (DNS) printer */

	#ifdef HAVE_CONFIG_H
	#include "config.h"
	#endif

	#include <netdissect-stdinc.h>

	#include "nameser.h"

	#include <string.h>

	#include "netdissect.h"
	#include "addrtoname.h"
	#include "addrtostr.h"
	#include "extract.h"

	static const char *ns_ops[] = {
	"", " inv_q", " stat", " op3", " notify", " update", " op6", " op7",
	" op8", " updateA", " updateD", " updateDA",
	" updateM", " updateMA", " zoneInit", " zoneRef",
	};

	static const char *ns_resp[] = {
	"", " FormErr", " ServFail", " NXDomain",
	" NotImp", " Refused", " YXDomain", " YXRRSet",
	" NXRRSet", " NotAuth", " NotZone", " Resp11",
	" Resp12", " Resp13", " Resp14", " NoChange",
	};

	/* skip over a domain name */
	static const u_char *
	ns_nskip(netdissect_options *ndo,
	register const u_char *cp)
	{
	register u_char i;

	if (!ND_TTEST2(*cp, 1))
	return (NULL);
	i = *cp++;
	while (i) {
	if ((i & INDIR_MASK) == INDIR_MASK)
	return (cp + 1);
	if ((i & INDIR_MASK) == EDNS0_MASK) {
	int bitlen, bytelen;

	if ((i & ~INDIR_MASK) != EDNS0_ELT_BITLABEL)
	return(NULL); /* unknown ELT */
	if (!ND_TTEST2(*cp, 1))
	return (NULL);
	if ((bitlen = *cp++) == 0)
	bitlen = 256;
	bytelen = (bitlen + 7) / 8;
	cp += bytelen;
	} else
	cp += i;
	if (!ND_TTEST2(*cp, 1))
	return (NULL);
	i = *cp++;
	}
	return (cp);
	}

	/* print a <domain-name> */
	static const u_char *
	blabel_print(netdissect_options *ndo,
	const u_char *cp)
	{
	int bitlen, slen, b;
	const u_char bitp, lim;
	char tc;

	if (!ND_TTEST2(*cp, 1))
	return(NULL);
	if ((bitlen = *cp) == 0)
	bitlen = 256;
	slen = (bitlen + 3) / 4;
	lim = cp + 1 + slen;

	/* print the bit string as a hex string */
	ND_PRINT((ndo, "\\[x"));
	for (bitp = cp + 1, b = bitlen; bitp < lim && b > 7; b -= 8, bitp++) {
	ND_TCHECK(*bitp);
	ND_PRINT((ndo, "%02x", *bitp));
	}
	if (b > 4) {
	ND_TCHECK(*bitp);
	tc = *bitp++;
	ND_PRINT((ndo, "%02x", tc & (0xff << (8 - b))));
	} else if (b > 0) {
	ND_TCHECK(*bitp);
	tc = *bitp++;
	ND_PRINT((ndo, "%1x", ((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
	}
	ND_PRINT((ndo, "/%d]", bitlen));
	return lim;
	trunc:
	ND_PRINT((ndo, ".../%d]", bitlen));
	return NULL;
	}

	static int
	labellen(netdissect_options *ndo,
	const u_char *cp)
	{
	register u_int i;

	if (!ND_TTEST2(*cp, 1))
	return(-1);
	i = *cp;
	if ((i & INDIR_MASK) == EDNS0_MASK) {
	int bitlen, elt;
	if ((elt = (i & ~INDIR_MASK)) != EDNS0_ELT_BITLABEL) {
	ND_PRINT((ndo, "<ELT %d>", elt));
	return(-1);
	}
	if (!ND_TTEST2(*(cp + 1), 1))
	return(-1);
	if ((bitlen = *(cp + 1)) == 0)
	bitlen = 256;
	return(((bitlen + 7) / 8) + 1);
	} else
	return(i);
	}

	const u_char *
	ns_nprint(netdissect_options *ndo,
	register const u_char cp, register const u_char bp)
	{
	register u_int i, l;
	register const u_char *rp = NULL;
	register int compress = 0;
	int elt;
	u_int offset, max_offset;

	if ((l = labellen(ndo, cp)) == (u_int)-1)
	return(NULL);
	if (!ND_TTEST2(*cp, 1))
	return(NULL);
	max_offset = (u_int)(cp - bp);
	if (((i = *cp++) & INDIR_MASK) != INDIR_MASK) {
	compress = 0;
	rp = cp + l;
	}

	if (i != 0)
	while (i && cp < ndo->ndo_snapend) {
	if ((i & INDIR_MASK) == INDIR_MASK) {
	if (!compress) {
	rp = cp + 1;
	compress = 1;
	}
	if (!ND_TTEST2(*cp, 1))
	return(NULL);
	offset = (((i << 8) \| *cp) & 0x3fff);
	/*
	* This must move backwards in the packet.
	* No RFC explicitly says that, but BIND's
	* name decompression code requires it,
	* as a way of preventing infinite loops
	* and other bad behavior, and it's probably
	* what was intended (compress by pointing
	* to domain name suffixes already seen in
	* the packet).
	*/
	if (offset >= max_offset) {
	ND_PRINT((ndo, "<BAD PTR>"));
	return(NULL);
	}
	max_offset = offset;
	cp = bp + offset;
	if ((l = labellen(ndo, cp)) == (u_int)-1)
	return(NULL);
	if (!ND_TTEST2(*cp, 1))
	return(NULL);
	i = *cp++;
	continue;
	}
	if ((i & INDIR_MASK) == EDNS0_MASK) {
	elt = (i & ~INDIR_MASK);
	switch(elt) {
	case EDNS0_ELT_BITLABEL:
	if (blabel_print(ndo, cp) == NULL)
	return (NULL);
	break;
	default:
	/* unknown ELT */
	ND_PRINT((ndo, "<ELT %d>", elt));
	return(NULL);
	}
	} else {
	if (fn_printn(ndo, cp, l, ndo->ndo_snapend))
	return(NULL);
	}

	cp += l;
	ND_PRINT((ndo, "."));
	if ((l = labellen(ndo, cp)) == (u_int)-1)
	return(NULL);
	if (!ND_TTEST2(*cp, 1))
	return(NULL);
	i = *cp++;
	if (!compress)
	rp += l + 1;
	}
	else
	ND_PRINT((ndo, "."));
	return (rp);
	}

	/* print a <character-string> */
	static const u_char *
	ns_cprint(netdissect_options *ndo,
	register const u_char *cp)
	{
	register u_int i;

	if (!ND_TTEST2(*cp, 1))
	return (NULL);
	i = *cp++;
	if (fn_printn(ndo, cp, i, ndo->ndo_snapend))
	return (NULL);
	return (cp + i);
	}

	/* http://www.iana.org/assignments/dns-parameters */
	const struct tok ns_type2str[] = {
	{ T_A, "A" }, /* RFC 1035 */
	{ T_NS, "NS" }, /* RFC 1035 */
	{ T_MD, "MD" }, /* RFC 1035 */
	{ T_MF, "MF" }, /* RFC 1035 */
	{ T_CNAME, "CNAME" }, /* RFC 1035 */
	{ T_SOA, "SOA" }, /* RFC 1035 */
	{ T_MB, "MB" }, /* RFC 1035 */
	{ T_MG, "MG" }, /* RFC 1035 */
	{ T_MR, "MR" }, /* RFC 1035 */
	{ T_NULL, "NULL" }, /* RFC 1035 */
	{ T_WKS, "WKS" }, /* RFC 1035 */
	{ T_PTR, "PTR" }, /* RFC 1035 */
	{ T_HINFO, "HINFO" }, /* RFC 1035 */
	{ T_MINFO, "MINFO" }, /* RFC 1035 */
	{ T_MX, "MX" }, /* RFC 1035 */
	{ T_TXT, "TXT" }, /* RFC 1035 */
	{ T_RP, "RP" }, /* RFC 1183 */
	{ T_AFSDB, "AFSDB" }, /* RFC 1183 */
	{ T_X25, "X25" }, /* RFC 1183 */
	{ T_ISDN, "ISDN" }, /* RFC 1183 */
	{ T_RT, "RT" }, /* RFC 1183 */
	{ T_NSAP, "NSAP" }, /* RFC 1706 */
	{ T_NSAP_PTR, "NSAP_PTR" },
	{ T_SIG, "SIG" }, /* RFC 2535 */
	{ T_KEY, "KEY" }, /* RFC 2535 */
	{ T_PX, "PX" }, /* RFC 2163 */
	{ T_GPOS, "GPOS" }, /* RFC 1712 */
	{ T_AAAA, "AAAA" }, /* RFC 1886 */
	{ T_LOC, "LOC" }, /* RFC 1876 */
	{ T_NXT, "NXT" }, /* RFC 2535 */
	{ T_EID, "EID" }, /* Nimrod */
	{ T_NIMLOC, "NIMLOC" }, /* Nimrod */
	{ T_SRV, "SRV" }, /* RFC 2782 */
	{ T_ATMA, "ATMA" }, /* ATM Forum */
	{ T_NAPTR, "NAPTR" }, /* RFC 2168, RFC 2915 */
	{ T_KX, "KX" }, /* RFC 2230 */
	{ T_CERT, "CERT" }, /* RFC 2538 */
	{ T_A6, "A6" }, /* RFC 2874 */
	{ T_DNAME, "DNAME" }, /* RFC 2672 */
	{ T_SINK, "SINK" },
	{ T_OPT, "OPT" }, /* RFC 2671 */
	{ T_APL, "APL" }, /* RFC 3123 */
	{ T_DS, "DS" }, /* RFC 4034 */
	{ T_SSHFP, "SSHFP" }, /* RFC 4255 */
	{ T_IPSECKEY, "IPSECKEY" }, /* RFC 4025 */
	{ T_RRSIG, "RRSIG" }, /* RFC 4034 */
	{ T_NSEC, "NSEC" }, /* RFC 4034 */
	{ T_DNSKEY, "DNSKEY" }, /* RFC 4034 */
	{ T_SPF, "SPF" }, /* RFC-schlitt-spf-classic-02.txt */
	{ T_UINFO, "UINFO" },
	{ T_UID, "UID" },
	{ T_GID, "GID" },
	{ T_UNSPEC, "UNSPEC" },
	{ T_UNSPECA, "UNSPECA" },
	{ T_TKEY, "TKEY" }, /* RFC 2930 */
	{ T_TSIG, "TSIG" }, /* RFC 2845 */
	{ T_IXFR, "IXFR" }, /* RFC 1995 */
	{ T_AXFR, "AXFR" }, /* RFC 1035 */
	{ T_MAILB, "MAILB" }, /* RFC 1035 */
	{ T_MAILA, "MAILA" }, /* RFC 1035 */
	{ T_ANY, "ANY" },
	{ 0, NULL }
	};

	const struct tok ns_class2str[] = {
	{ C_IN, "IN" }, /* Not used */
	{ C_CHAOS, "CHAOS" },
	{ C_HS, "HS" },
	{ C_ANY, "ANY" },
	{ 0, NULL }
	};

	/* print a query */
	static const u_char *
	ns_qprint(netdissect_options *ndo,
	register const u_char cp, register const u_char bp, int is_mdns)
	{
	register const u_char *np = cp;
	register u_int i, class;

	cp = ns_nskip(ndo, cp);

	if (cp == NULL \|\| !ND_TTEST2(*cp, 4))
	return(NULL);

	/* print the qtype */
	i = EXTRACT_16BITS(cp);
	cp += 2;
	ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", i)));
	/* print the qclass (if it's not IN) */
	i = EXTRACT_16BITS(cp);
	cp += 2;
	if (is_mdns)
	class = (i & ~C_QU);
	else
	class = i;
	if (class != C_IN)
	ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class)));
	if (is_mdns) {
	ND_PRINT((ndo, i & C_QU ? " (QU)" : " (QM)"));
	}

	ND_PRINT((ndo, "? "));
	cp = ns_nprint(ndo, np, bp);
	return(cp ? cp + 4 : NULL);
	}

	/* print a reply */
	static const u_char *
	ns_rprint(netdissect_options *ndo,
	register const u_char cp, register const u_char bp, int is_mdns)
	{
	register u_int i, class, opt_flags = 0;
	register u_short typ, len;
	register const u_char *rp;

	if (ndo->ndo_vflag) {
	ND_PRINT((ndo, " "));
	if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
	return NULL;
	} else
	cp = ns_nskip(ndo, cp);

	if (cp == NULL \|\| !ND_TTEST2(*cp, 10))
	return (ndo->ndo_snapend);

	/* print the type/qtype */
	typ = EXTRACT_16BITS(cp);
	cp += 2;
	/* print the class (if it's not IN and the type isn't OPT) */
	i = EXTRACT_16BITS(cp);
	cp += 2;
	if (is_mdns)
	class = (i & ~C_CACHE_FLUSH);
	else
	class = i;
	if (class != C_IN && typ != T_OPT)
	ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class)));
	if (is_mdns) {
	if (i & C_CACHE_FLUSH)
	ND_PRINT((ndo, " (Cache flush)"));
	}

	if (typ == T_OPT) {
	/* get opt flags */
	cp += 2;
	opt_flags = EXTRACT_16BITS(cp);
	/* ignore rest of ttl field */
	cp += 2;
	} else if (ndo->ndo_vflag > 2) {
	/* print ttl */
	ND_PRINT((ndo, " ["));
	unsigned_relts_print(ndo, EXTRACT_32BITS(cp));
	ND_PRINT((ndo, "]"));
	cp += 4;
	} else {
	/* ignore ttl */
	cp += 4;
	}

	len = EXTRACT_16BITS(cp);
	cp += 2;

	rp = cp + len;

	ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", typ)));
	if (rp > ndo->ndo_snapend)
	return(NULL);

	switch (typ) {
	case T_A:
	if (!ND_TTEST2(*cp, sizeof(struct in_addr)))
	return(NULL);
	ND_PRINT((ndo, " %s", intoa(htonl(EXTRACT_32BITS(cp)))));
	break;

	case T_NS:
	case T_CNAME:
	case T_PTR:
	#ifdef T_DNAME
	case T_DNAME:
	#endif
	ND_PRINT((ndo, " "));
	if (ns_nprint(ndo, cp, bp) == NULL)
	return(NULL);
	break;

	case T_SOA:
	if (!ndo->ndo_vflag)
	break;
	ND_PRINT((ndo, " "));
	if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
	return(NULL);
	ND_PRINT((ndo, " "));
	if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
	return(NULL);
	if (!ND_TTEST2(cp, 5 4))
	return(NULL);
	ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
	cp += 4;
	ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
	cp += 4;
	ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
	cp += 4;
	ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
	cp += 4;
	ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
	cp += 4;
	break;
	case T_MX:
	ND_PRINT((ndo, " "));
	if (!ND_TTEST2(*cp, 2))
	return(NULL);
	if (ns_nprint(ndo, cp + 2, bp) == NULL)
	return(NULL);
	ND_PRINT((ndo, " %d", EXTRACT_16BITS(cp)));
	break;

	case T_TXT:
	while (cp < rp) {
	ND_PRINT((ndo, " \""));
	cp = ns_cprint(ndo, cp);
	if (cp == NULL)
	return(NULL);
	ND_PRINT((ndo, "\""));
	}
	break;

	case T_SRV:
	ND_PRINT((ndo, " "));
	if (!ND_TTEST2(*cp, 6))
	return(NULL);
	if (ns_nprint(ndo, cp + 6, bp) == NULL)
	return(NULL);
	ND_PRINT((ndo, ":%d %d %d", EXTRACT_16BITS(cp + 4),
	EXTRACT_16BITS(cp), EXTRACT_16BITS(cp + 2)));
	break;

	case T_AAAA:
	{
	char ntop_buf[INET6_ADDRSTRLEN];

	if (!ND_TTEST2(*cp, sizeof(struct in6_addr)))
	return(NULL);
	ND_PRINT((ndo, " %s",
	addrtostr6(cp, ntop_buf, sizeof(ntop_buf))));

	break;
	}

	case T_A6:
	{
	struct in6_addr a;
	int pbit, pbyte;
	char ntop_buf[INET6_ADDRSTRLEN];

	if (!ND_TTEST2(*cp, 1))
	return(NULL);
	pbit = *cp;
	pbyte = (pbit & ~7) / 8;
	if (pbit > 128) {
	ND_PRINT((ndo, " %u(bad plen)", pbit));
	break;
	} else if (pbit < 128) {
	if (!ND_TTEST2(*(cp + 1), sizeof(a) - pbyte))
	return(NULL);
	memset(&a, 0, sizeof(a));
	memcpy(&a.s6_addr[pbyte], cp + 1, sizeof(a) - pbyte);
	ND_PRINT((ndo, " %u %s", pbit,
	addrtostr6(&a, ntop_buf, sizeof(ntop_buf))));
	}
	if (pbit > 0) {
	ND_PRINT((ndo, " "));
	if (ns_nprint(ndo, cp + 1 + sizeof(a) - pbyte, bp) == NULL)
	return(NULL);
	}
	break;
	}

	case T_OPT:
	ND_PRINT((ndo, " UDPsize=%u", class));
	if (opt_flags & 0x8000)
	ND_PRINT((ndo, " DO"));
	break;

	case T_UNSPECA: /* One long string */
	if (!ND_TTEST2(*cp, len))
	return(NULL);
	if (fn_printn(ndo, cp, len, ndo->ndo_snapend))
	return(NULL);
	break;

	case T_TSIG:
	{
	if (cp + len > ndo->ndo_snapend)
	return(NULL);
	if (!ndo->ndo_vflag)
	break;
	ND_PRINT((ndo, " "));
	if ((cp = ns_nprint(ndo, cp, bp)) == NULL)
	return(NULL);
	cp += 6;
	if (!ND_TTEST2(*cp, 2))
	return(NULL);
	ND_PRINT((ndo, " fudge=%u", EXTRACT_16BITS(cp)));
	cp += 2;
	if (!ND_TTEST2(*cp, 2))
	return(NULL);
	ND_PRINT((ndo, " maclen=%u", EXTRACT_16BITS(cp)));
	cp += 2 + EXTRACT_16BITS(cp);
	if (!ND_TTEST2(*cp, 2))
	return(NULL);
	ND_PRINT((ndo, " origid=%u", EXTRACT_16BITS(cp)));
	cp += 2;
	if (!ND_TTEST2(*cp, 2))
	return(NULL);
	ND_PRINT((ndo, " error=%u", EXTRACT_16BITS(cp)));
	cp += 2;
	if (!ND_TTEST2(*cp, 2))
	return(NULL);
	ND_PRINT((ndo, " otherlen=%u", EXTRACT_16BITS(cp)));
	cp += 2;
	}
	}
	return (rp); /* XXX This isn't always right */
	}

	void
	ns_print(netdissect_options *ndo,
	register const u_char *bp, u_int length, int is_mdns)
	{
	register const HEADER *np;
	register int qdcount, ancount, nscount, arcount;
	register const u_char *cp;
	uint16_t b2;

	np = (const HEADER *)bp;
	ND_TCHECK(*np);
	/* get the byte-order right */
	qdcount = EXTRACT_16BITS(&np->qdcount);
	ancount = EXTRACT_16BITS(&np->ancount);
	nscount = EXTRACT_16BITS(&np->nscount);
	arcount = EXTRACT_16BITS(&np->arcount);

	if (DNS_QR(np)) {
	/* this is a response */
	ND_PRINT((ndo, "%d%s%s%s%s%s%s",
	EXTRACT_16BITS(&np->id),
	ns_ops[DNS_OPCODE(np)],
	ns_resp[DNS_RCODE(np)],
	DNS_AA(np)? "*" : "",
	DNS_RA(np)? "" : "-",
	DNS_TC(np)? "\|" : "",
	DNS_AD(np)? "$" : ""));

	if (qdcount != 1)
	ND_PRINT((ndo, " [%dq]", qdcount));
	/* Print QUESTION section on -vv */
	cp = (const u_char *)(np + 1);
	while (qdcount--) {
	if (qdcount < EXTRACT_16BITS(&np->qdcount) - 1)
	ND_PRINT((ndo, ","));
	if (ndo->ndo_vflag > 1) {
	ND_PRINT((ndo, " q:"));
	if ((cp = ns_qprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	} else {
	if ((cp = ns_nskip(ndo, cp)) == NULL)
	goto trunc;
	cp += 4; /* skip QTYPE and QCLASS */
	}
	}
	ND_PRINT((ndo, " %d/%d/%d", ancount, nscount, arcount));
	if (ancount--) {
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	while (cp < ndo->ndo_snapend && ancount--) {
	ND_PRINT((ndo, ","));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	}
	}
	if (ancount > 0)
	goto trunc;
	/* Print NS and AR sections on -vv */
	if (ndo->ndo_vflag > 1) {
	if (cp < ndo->ndo_snapend && nscount--) {
	ND_PRINT((ndo, " ns:"));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	while (cp < ndo->ndo_snapend && nscount--) {
	ND_PRINT((ndo, ","));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	}
	}
	if (nscount > 0)
	goto trunc;
	if (cp < ndo->ndo_snapend && arcount--) {
	ND_PRINT((ndo, " ar:"));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	while (cp < ndo->ndo_snapend && arcount--) {
	ND_PRINT((ndo, ","));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	}
	}
	if (arcount > 0)
	goto trunc;
	}
	}
	else {
	/* this is a request */
	ND_PRINT((ndo, "%d%s%s%s", EXTRACT_16BITS(&np->id), ns_ops[DNS_OPCODE(np)],
	DNS_RD(np) ? "+" : "",
	DNS_CD(np) ? "%" : ""));

	/* any weirdness? */
	b2 = EXTRACT_16BITS(((const u_short *)np)+1);
	if (b2 & 0x6cf)
	ND_PRINT((ndo, " [b2&3=0x%x]", b2));

	if (DNS_OPCODE(np) == IQUERY) {
	if (qdcount)
	ND_PRINT((ndo, " [%dq]", qdcount));
	if (ancount != 1)
	ND_PRINT((ndo, " [%da]", ancount));
	}
	else {
	if (ancount)
	ND_PRINT((ndo, " [%da]", ancount));
	if (qdcount != 1)
	ND_PRINT((ndo, " [%dq]", qdcount));
	}
	if (nscount)
	ND_PRINT((ndo, " [%dn]", nscount));
	if (arcount)
	ND_PRINT((ndo, " [%dau]", arcount));

	cp = (const u_char *)(np + 1);
	if (qdcount--) {
	cp = ns_qprint(ndo, cp, (const u_char *)np, is_mdns);
	if (!cp)
	goto trunc;
	while (cp < ndo->ndo_snapend && qdcount--) {
	cp = ns_qprint(ndo, (const u_char *)cp,
	(const u_char *)np,
	is_mdns);
	if (!cp)
	goto trunc;
	}
	}
	if (qdcount > 0)
	goto trunc;

	/* Print remaining sections on -vv */
	if (ndo->ndo_vflag > 1) {
	if (ancount--) {
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	while (cp < ndo->ndo_snapend && ancount--) {
	ND_PRINT((ndo, ","));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	}
	}
	if (ancount > 0)
	goto trunc;
	if (cp < ndo->ndo_snapend && nscount--) {
	ND_PRINT((ndo, " ns:"));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	while (nscount-- && cp < ndo->ndo_snapend) {
	ND_PRINT((ndo, ","));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	}
	}
	if (nscount > 0)
	goto trunc;
	if (cp < ndo->ndo_snapend && arcount--) {
	ND_PRINT((ndo, " ar:"));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	while (cp < ndo->ndo_snapend && arcount--) {
	ND_PRINT((ndo, ","));
	if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL)
	goto trunc;
	}
	}
	if (arcount > 0)
	goto trunc;
	}
	}
	ND_PRINT((ndo, " (%d)", length));
	return;

	trunc:
	ND_PRINT((ndo, "[\|domain]"));
	}