4.3BSD/usr/include/arpa/nameser.h

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)nameser.h	5.11 (Berkeley) 2/14/86
 */

/*
 * Define constants based on rfc883
 */
#define PACKETSZ	512		/* maximum packet size */
#define MAXDNAME	256		/* maximum domain name */
#define MAXCDNAME	255		/* maximum compressed domain name */
#define MAXLABEL	63		/* maximum length of domain label */
	/* Number of bytes of fixed size data in query structure */
#define QFIXEDSZ	4
	/* number of bytes of fixed size data in resource record */
#define RRFIXEDSZ	10

/*
 * Internet nameserver port number
 */
#define NAMESERVER_PORT	53

/*
 * Currently defined opcodes
 */
#define QUERY		0		/* standard query */
#define IQUERY		1		/* inverse query */
#define CQUERYM		2		/* completion query (multiple) */
#define CQUERYU		3		/* completion query (unique) */
	/* non standard */
#define UPDATEA		100		/* add resource record */
#define UPDATED		101		/* delete resource record */
#define UPDATEM		102		/* modify resource record */
#define ZONEINIT	103		/* initial zone transfer */
#define ZONEREF		104		/* incremental zone referesh */

/*
 * Currently defined response codes
 */
#define NOERROR		0		/* no error */
#define FORMERR		1		/* format error */
#define SERVFAIL	2		/* server failure */
#define NXDOMAIN	3		/* non existent domain */
#define NOTIMP		4		/* not implemented */
#define REFUSED		5		/* query refused */
	/* non standard */
#define NOCHANGE	100		/* update failed to change db */

/*
 * Type values for resources and queries
 */
#define T_A		1		/* host address */
#define T_NS		2		/* authoritative server */
#define T_MD		3		/* mail destination */
#define T_MF		4		/* mail forwarder */
#define T_CNAME		5		/* connonical name */
#define T_SOA		6		/* start of authority zone */
#define T_MB		7		/* mailbox domain name */
#define T_MG		8		/* mail group member */
#define T_MR		9		/* mail rename name */
#define T_NULL		10		/* null resource record */
#define T_WKS		11		/* well known service */
#define T_PTR		12		/* domain name pointer */
#define T_HINFO		13		/* host information */
#define T_MINFO		14		/* mailbox information */
#define T_MX		15		/* mail routing information */
	/* non standard */
#define T_UINFO		100		/* user (finger) information */
#define T_UID		101		/* user ID */
#define T_GID		102		/* group ID */
	/* Query type values which do not appear in resource records */
#define T_AXFR		252		/* transfer zone of authority */
#define T_MAILB		253		/* transfer mailbox records */
#define T_MAILA		254		/* transfer mail agent records */
#define T_ANY		255		/* wildcard match */

/*
 * Values for class field
 */

#define C_IN		1		/* the arpa internet */
#define C_CHAOS		3		/* for chaos net at MIT */
	/* Query class values which do not appear in resource records */
#define C_ANY		255		/* wildcard match */

/*
 * Structure for query header, the order of the fields is machine and
 * compiler dependent, in our case, the bits within a byte are assignd 
 * least significant first, while the order of transmition is most 
 * significant first.  This requires a somewhat confusing rearrangement.
 */

typedef struct {
	u_short	id;		/* query identification number */
#if defined (sun) || defined (sel) || defined (pyr) || defined (is68k) \
|| defined (tahoe) || defined (BIT_ZERO_ON_LEFT)
	/* Bit zero on left:  Gould and similar architectures */
			/* fields in third byte */
	u_char	qr:1;		/* response flag */
	u_char	opcode:4;	/* purpose of message */
	u_char	aa:1;		/* authoritive answer */
	u_char	tc:1;		/* truncated message */
	u_char	rd:1;		/* recursion desired */
			/* fields in fourth byte */
	u_char	ra:1;		/* recursion available */
	u_char	pr:1;		/* primary server required (non standard) */
	u_char	unused:2;	/* unused bits */
	u_char	rcode:4;	/* response code */
#else
#if defined (vax) || defined (BIT_ZERO_ON_RIGHT)
	/* Bit zero on right:  VAX */
			/* fields in third byte */
	u_char	rd:1;		/* recursion desired */
	u_char	tc:1;		/* truncated message */
	u_char	aa:1;		/* authoritive answer */
	u_char	opcode:4;	/* purpose of message */
	u_char	qr:1;		/* response flag */
			/* fields in fourth byte */
	u_char	rcode:4;	/* response code */
	u_char	unused:2;	/* unused bits */
	u_char	pr:1;		/* primary server required (non standard) */
	u_char	ra:1;		/* recursion available */
#else
	/* you must determine what the correct bit order is for your compiler */
	UNDEFINED_BIT_ORDER;
#endif
#endif
			/* remaining bytes */
	u_short	qdcount;	/* number of question entries */
	u_short	ancount;	/* number of answer entries */
	u_short	nscount;	/* number of authority entries */
	u_short	arcount;	/* number of resource entries */
} HEADER;

/*
 * Defines for handling compressed domain names
 */
#define INDIR_MASK	0xc0

/*
 * Structure for passing resource records around.
 */
struct rrec {
	short	r_zone;			/* zone number */
	short	r_class;		/* class number */
	short	r_type;			/* type number */
	u_long	r_ttl;			/* time to live */
	int	r_size;			/* size of data area */
	char	*r_data;		/* pointer to data */
};

extern	u_short	getshort();
extern	u_long	getlong();