/* 
 * dns/reslib.h
 *
 * $Id: reslib.h 446 2006-02-12 02:46:54Z db $
 */

#ifndef __MOWGLI_DNS_RESLIB_H__
#define __MOWGLI_DNS_RESLIB_H__

/* Here we define some values lifted from nameser.h */
#define MOWGLI_DNS_NS_NOTIFY_OP		4
#define MOWGLI_DNS_NS_INT16SIZE		2
#define MOWGLI_DNS_NS_IN6ADDRSIZE	16
#define MOWGLI_DNS_NS_INADDRSIZE	4
#define MOWGLI_DNS_NS_INT32SIZE		4
#define MOWGLI_DNS_NS_CMPRSFLAGS	0xc0
#define MOWGLI_DNS_NS_MAXCDNAME		255
#define MOWGLI_DNS_QUERY		0
#define MOWGLI_DNS_IQUERY		1
#define MOWGLI_DNS_NO_ERRORS		0
#define MOWGLI_DNS_SERVFAIL		2
#define MOWGLI_DNS_NXDOMAIN		3
#define MOWGLI_DNS_C_IN			1
#define MOWGLI_DNS_QFIXEDSIZE		4
#define MOWGLI_DNS_RRFIXEDSIZE		10
#define MOWGLI_DNS_HFIXEDSIZE		12

typedef struct
{
	unsigned id:16;				/* query identification number */
#ifdef WORDS_BIGENDIAN
	/* fields in third byte */
	unsigned qr:1;				/* response flag */
	unsigned opcode:4;			/* purpose of message */
	unsigned aa:1;				/* authoritive answer */
	unsigned tc:1;				/* truncated message */
	unsigned rd:1;				/* recursion desired */
	/* fields in fourth byte */
	unsigned ra:1;				/* recursion available */
	unsigned unused:1;			/* unused bits (MBZ as of 4.9.3a3) */
	unsigned ad:1;				/* authentic data from named */
	unsigned cd:1;				/* checking disabled by resolver */
	unsigned rcode:4;			/* response code */
#else
	/* fields in third byte */
	unsigned rd:1;				/* recursion desired */
	unsigned tc:1;				/* truncated message */
	unsigned aa:1;				/* authoritive answer */
	unsigned opcode:4;			/* purpose of message */
	unsigned qr:1;				/* response flag */
	/* fields in fourth byte */
	unsigned rcode:4;			/* response code */
	unsigned cd:1;				/* checking disabled by resolver */
	unsigned ad:1;				/* authentic data from named */
	unsigned unused:1;			/* unused bits (MBZ as of 4.9.3a3) */
	unsigned ra:1;				/* recursion available */
#endif
	/* remaining bytes */
	unsigned qdcount:16;		/* number of question entries */
	unsigned ancount:16;		/* number of answer entries */
	unsigned nscount:16;		/* number of authority entries */
	unsigned arcount:16;		/* number of resource entries */
} mowgli_dns_resheader_t;

/* 
 * Inline versions of get/put short/long.  Pointer is advanced.
 */
#define MOWGLI_DNS_NS_GET16(s, cp) { \
	const unsigned char *t_cp = (const unsigned char *)(cp); \
	(s) = ((uint16_t)t_cp[0] << 8) \
	    | ((uint16_t)t_cp[1]) \
	    ; \
	(cp) += MOWGLI_DNS_NS_INT16SIZE; \
}

#define MOWGLI_DNS_NS_GET32(l, cp) { \
	const unsigned char *t_cp = (const unsigned char *)(cp); \
	(l) = ((uint32_t)t_cp[0] << 24) \
	    | ((uint32_t)t_cp[1] << 16) \
	    | ((uint32_t)t_cp[2] << 8) \
	    | ((uint32_t)t_cp[3]) \
	    ; \
	(cp) += MOWGLI_DNS_NS_INT32SIZE; \
}

#define MOWGLI_DNS_NS_PUT16(s, cp) { \
	uint16_t t_s = (uint16_t)(s); \
	unsigned char *t_cp = (unsigned char *)(cp); \
	*t_cp++ = t_s >> 8; \
	*t_cp   = t_s; \
	(cp) += MOWGLI_DNS_NS_INT16SIZE; \
}

#define MOWGLI_DNS_NS_PUT32(l, cp) { \
	uint32_t t_l = (uint32_t)(l); \
	unsigned char *t_cp = (unsigned char *)(cp); \
	*t_cp++ = t_l >> 24; \
	*t_cp++ = t_l >> 16; \
	*t_cp++ = t_l >> 8; \
	*t_cp   = t_l; \
	(cp) += MOWGLI_DNS_NS_INT32SIZE; \
}

extern int mowgli_dns_dn_expand(const unsigned char *msg, const unsigned char *eom, const unsigned char *src, char *dst, int dstsiz);
extern int mowgli_dns_dn_skipname(const unsigned char *ptr, const unsigned char *eom);
extern unsigned int mowgli_dns_ns_get16(const unsigned char *src);
extern unsigned long mowgli_dns_ns_get32(const unsigned char *src);
extern void mowgli_dns_ns_put16(unsigned int src, unsigned char *dst);
extern void mowgli_dns_ns_put32(unsigned long src, unsigned char *dst);
extern int mowgli_dns_res_mkquery(const char *dname, int query_class, int type, unsigned char *buf, int buflen);

#endif