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LWRES_GETIPNODE(3)		     BIND9		    LWRES_GETIPNODE(3)

NAME
       lwres_getipnodebyname, lwres_getipnodebyaddr, lwres_freehostent -
       lightweight resolver nodename / address translation API

SYNOPSIS
       #include	<lwres/netdb.h>

       struct hostent *	lwres_getipnodebyname(const char *name,	int af,
					      int flags, int *error_num);

       struct hostent *	lwres_getipnodebyaddr(const void *src, size_t len,
					      int af, int *error_num);

       void lwres_freehostent(struct hostent *he);

DESCRIPTION
       These functions perform thread safe, protocol independent
       nodename-to-address and address-to-nodename translation as defined in
       RFC2553.

       They use	a struct hostent which is defined in namedb.h:

	   struct  hostent {
		   char	   *h_name;	   /* official name of host */
		   char	   **h_aliases;	   /* alias list */
		   int	   h_addrtype;	   /* host address type	*/
		   int	   h_length;	   /* length of	address	*/
		   char	   **h_addr_list;  /* list of addresses	from name server */
	   };
	   #define h_addr  h_addr_list[0]  /* address, for backward compatibility */

       The members of this structure are:

       h_name
	   The official	(canonical) name of the	host.

       h_aliases
	   A NULL-terminated array of alternate	names (nicknames) for the
	   host.

       h_addrtype
	   The type of address being returned -	usually	PF_INET	or PF_INET6.

       h_length
	   The length of the address in	bytes.

       h_addr_list
	   A NULL terminated array of network addresses	for the	host. Host
	   addresses are returned in network byte order.

       lwres_getipnodebyname() looks up	addresses of protocol family af	for
       the hostname name. The flags parameter contains ORed flag bits to
       specify the types of addresses that are searched	for, and the types of
       addresses that are returned. The	flag bits are:

       AI_V4MAPPED
	   This	is used	with an	af of AF_INET6,	and causes IPv4	addresses to
	   be returned as IPv4-mapped IPv6 addresses.

       AI_ALL
	   This	is used	with an	af of AF_INET6,	and causes all known addresses
	   (IPv6 and IPv4) to be returned. If AI_V4MAPPED is also set, the
	   IPv4	addresses are return as	mapped IPv6 addresses.

       AI_ADDRCONFIG
	   Only	return an IPv6 or IPv4 address if here is an active network
	   interface of	that type. This	is not currently implemented in	the
	   BIND	9 lightweight resolver,	and the	flag is	ignored.

       AI_DEFAULT
	   This	default	sets the AI_V4MAPPED and AI_ADDRCONFIG flag bits.

       lwres_getipnodebyaddr() performs	a reverse lookup of address src	which
       is len bytes long.  af denotes the protocol family, typically PF_INET
       or PF_INET6.

       lwres_freehostent() releases all	the memory associated with the struct
       hostent pointer he. Any memory allocated	for the	h_name,	h_addr_list
       and h_aliases is	freed, as is the memory	for the	hostent	structure
       itself.

RETURN VALUES
       If an error occurs, lwres_getipnodebyname() and lwres_getipnodebyaddr()
       set *error_num to an appropriate	error code and the function returns a
       NULL pointer. The error codes and their meanings	are defined in
       _lwres/netdb.h_:

       HOST_NOT_FOUND
	   No such host	is known.

       NO_ADDRESS
	   The server recognised the request and the name but no address is
	   available. Another type of request to the name server for the
	   domain might	return an answer.

       TRY_AGAIN
	   A temporary and possibly transient error occurred, such as a
	   failure of a	server to respond. The request may succeed if retried.

       NO_RECOVERY
	   An unexpected failure occurred, and retrying	the request is
	   pointless.

       lwres_hstrerror(3) translates these error codes to suitable error
       messages.

SEE ALSO
       RFC2553(), lwres(3), lwres_gethostent(3), lwres_getaddrinfo(3),
       lwres_getnameinfo(3), lwres_hstrerror(3).

COPYRIGHT
       Copyright (C) 2004, 2005, 2007, 2012 Internet Systems Consortium, Inc.
       ("ISC")
       Copyright (C) 2000, 2001, 2003 Internet Software	Consortium.

BIND9				 Jun 30, 2000		    LWRES_GETIPNODE(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | COPYRIGHT

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