ares.h

/* $Id: ares.h,v 1.5 2006-11-27 20:42:27 ghudson Exp $ */

/* Copyright 1998, 2002 by the Massachusetts Institute of Technology.
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting
 * documentation, and that the name of M.I.T. not be used in
 * advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 */

#ifndef ARES__H
#define ARES__H

#include <sys/types.h>
#include <netinet/in.h>

#define ARES_SUCCESS			0

/* Server error codes (ARES_ENODATA indicates no relevant answer) */
#define ARES_ENODATA			1
#define ARES_EFORMERR			2
#define ARES_ESERVFAIL			3
#define ARES_ENOTFOUND			4
#define ARES_ENOTIMP			5
#define ARES_EREFUSED			6

/* Locally generated error codes */
#define ARES_EBADQUERY			7
#define ARES_EBADNAME			8
#define ARES_EBADFAMILY			9
#define ARES_EBADRESP			10
#define ARES_ECONNREFUSED		11
#define ARES_ETIMEOUT			12
#define ARES_EOF			13
#define ARES_EFILE			14
#define ARES_ENOMEM			15
#define ARES_EDESTRUCTION		16

/* Flag values */
#define ARES_FLAG_USEVC			(1 << 0)
#define ARES_FLAG_PRIMARY		(1 << 1)
#define ARES_FLAG_IGNTC			(1 << 2)
#define ARES_FLAG_NORECURSE		(1 << 3)
#define ARES_FLAG_STAYOPEN		(1 << 4)
#define ARES_FLAG_NOSEARCH		(1 << 5)
#define ARES_FLAG_NOALIASES		(1 << 6)
#define ARES_FLAG_NOCHECKRESP		(1 << 7)

/* Option mask values */
#define ARES_OPT_FLAGS			(1 << 0)
#define ARES_OPT_TIMEOUT		(1 << 1)
#define ARES_OPT_TRIES			(1 << 2)
#define ARES_OPT_NDOTS			(1 << 3)
#define ARES_OPT_UDP_PORT		(1 << 4)
#define ARES_OPT_TCP_PORT		(1 << 5)
#define ARES_OPT_SERVERS		(1 << 6)
#define ARES_OPT_DOMAINS		(1 << 7)
#define ARES_OPT_LOOKUPS		(1 << 8)

#define ARES_DNS_OPCODE_QUERY		0
#define ARES_DNS_OPCODE_IQUERY		1
#define ARES_DNS_OPCODE_STATUS		2
#define ARES_DNS_OPCODE_NOTIFY		4
#define ARES_DNS_OPCODE_UPDATEA		9
#define ARES_DNS_OPCODE_UPDATED		10
#define ARES_DNS_OPCODE_UPDATEDA	11
#define ARES_DNS_OPCODE_UPDATEM		12
#define ARES_DNS_OPCODE_UPDATEMA	13
#define ARES_DNS_OPCODE_ZONEINIT	14
#define ARES_DNS_OPCODE_ZONEREF		15

#define ARES_DNS_RCODE_NOERROR		0
#define ARES_DNS_RCODE_FORMERR		1
#define ARES_DNS_RCODE_SERVFAIL		2
#define ARES_DNS_RCODE_NXDOMAIN		3
#define ARES_DNS_RCODE_NOTIMP		4
#define ARES_DNS_RCODE_REFUSED		5
#define ARES_DNS_RCODE_NOCHANGE		15

struct ares_options {
  int flags;
  int timeout;
  int tries;
  int ndots;
  unsigned short udp_port;
  unsigned short tcp_port;
  struct in_addr *servers;
  int nservers;
  char **domains;
  int ndomains;
  char *lookups;
};

struct ares_dns_question {
  char *name;
  int type;
  int dnsclass;
};

struct ares_dns_rr {
  char *name;
  int type;
  int dnsclass;
  int ttl;
  int len;
  unsigned char *data;
};

struct ares_dns_section {
  int count;
  struct ares_dns_rr *records;
};

struct ares_dns_message {
  int id;
  int is_response;
  int opcode;
  int authoritative_answer;
  int truncated;
  int recursion_desired;
  int recursion_available;
  int zero;
  int response_code;
  int qcount;
  struct ares_dns_question *questions;
  struct ares_dns_section answers;
  struct ares_dns_section authority;
  struct ares_dns_section additional;
};

struct hostent;
struct timeval;
struct ares_channeldata;
typedef struct ares_channeldata *ares_channel;
typedef void (*ares_callback)(void *arg, int status, unsigned char *abuf,
			      int alen);
typedef void (*ares_host_callback)(void *arg, int status,
				   struct hostent *hostent);

int ares_init(ares_channel *channelptr);
int ares_init_options(ares_channel *channelptr, struct ares_options *options,
		      int optmask);
void ares_destroy(ares_channel channel);

void ares_send(ares_channel channel, const unsigned char *qbuf, int qlen,
	       ares_callback callback, void *arg);
void ares_query(ares_channel channel, const char *name, int dnsclass,
		int type, ares_callback callback, void *arg);
void ares_search(ares_channel channel, const char *name, int dnsclass,
		 int type, ares_callback callback, void *arg);
void ares_gethostbyname(ares_channel channel, const char *name, int family,
			ares_host_callback callback, void *arg);
void ares_gethostbyaddr(ares_channel channel, const void *addr, int addrlen,
			int family, ares_host_callback callback, void *arg);

int ares_fds(ares_channel channel, fd_set *read_fds, fd_set *write_fds);
struct timeval *ares_timeout(ares_channel channel, struct timeval *maxtv,
			     struct timeval *tv);
void ares_process(ares_channel channel, fd_set *read_fds, fd_set *write_fds);

int ares_mkquery(const char *name, int dnsclass, int type, unsigned short id,
		 int rd, unsigned char **buf, int *buflen);
int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf,
		     int alen, char **s, int *enclen);
int ares_parse_message(const unsigned char *abuf, int alen,
		       struct ares_dns_message **message);
int ares_parse_a_reply(const unsigned char *abuf, int alen,
		       struct hostent **host);
int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
			 int addrlen, int family, struct hostent **host);

void ares_free_string(void *str);
void ares_free_dns_message(struct ares_dns_message *message);
void ares_free_hostent(struct hostent *host);
const char *ares_strerror(int code, char **memptr);
void ares_free_errmem(char *mem);

#endif /* ARES__H */