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LWRES_PACKET(3)			     BIND9		       LWRES_PACKET(3)

NAME
       lwres_lwpacket_renderheader, lwres_lwpacket_parseheader - lightweight
       resolver	packet handling	functions

SYNOPSIS
       #include	<lwres/lwpacket.h>

       lwres_result_t lwres_lwpacket_renderheader(lwres_buffer_t *b,
						  lwres_lwpacket_t *pkt);

       lwres_result_t lwres_lwpacket_parseheader(lwres_buffer_t	*b,
						 lwres_lwpacket_t *pkt);

DESCRIPTION
       These functions rely on a struct	lwres_lwpacket which is	defined	in
       lwres/lwpacket.h.

	   typedef struct lwres_lwpacket lwres_lwpacket_t;

	   struct lwres_lwpacket {
		   uint32_t	     length;
		   uint16_t	     version;
		   uint16_t	     pktflags;
		   uint32_t	     serial;
		   uint32_t	     opcode;
		   uint32_t	     result;
		   uint32_t	     recvlength;
		   uint16_t	     authtype;
		   uint16_t	     authlength;
	   };

       The elements of this structure are:

       length
	   the overall packet length, including	the entire packet header. This
	   field is filled in by the lwres_gabn_*() and	lwres_gnba_*() calls.

       version
	   the header format. There is currently only one format,
	   LWRES_LWPACKETVERSION_0. This field is filled in by the
	   lwres_gabn_*() and lwres_gnba_*() calls.

       pktflags
	   library-defined flags for this packet: for instance whether the
	   packet is a request or a reply. Flag	values can be set, but not
	   defined by the caller. This field is	filled in by the application
	   with	the exception of the LWRES_LWPACKETFLAG_RESPONSE bit, which is
	   set by the library in the lwres_gabn_*() and	lwres_gnba_*() calls.

       serial
	   is set by the requestor and is returned in all replies. If two or
	   more	packets	from the same source have the same serial number and
	   are from the	same source, they are assumed to be duplicates and the
	   latter ones may be dropped. This field must be set by the
	   application.

       opcode
	   indicates the operation. Opcodes between 0x00000000 and 0x03ffffff
	   are reserved	for use	by the lightweight resolver library. Opcodes
	   between 0x04000000 and 0xffffffff are application defined. This
	   field is filled in by the lwres_gabn_*() and	lwres_gnba_*() calls.

       result
	   is only valid for replies. Results between 0x04000000 and
	   0xffffffff are application defined. Results between 0x00000000 and
	   0x03ffffff are reserved for library use. This field is filled in by
	   the lwres_gabn_*() and lwres_gnba_*() calls.

       recvlength
	   is the maximum buffer size that the receiver	can handle on requests
	   and the size	of the buffer needed to	satisfy	a request when the
	   buffer is too large for replies. This field is supplied by the
	   application.

       authtype
	   defines the packet level authentication that	is used. Authorisation
	   types between 0x1000	and 0xffff are application defined and types
	   between 0x0000 and 0x0fff are reserved for library use. Currently
	   these are not used and must be zero.

       authlen
	   gives the length of the authentication data.	Since packet
	   authentication is currently not used, this must be zero.

       The following opcodes are currently defined:

       NOOP
	   Success is always returned and the packet contents are echoed. The
	   lwres_noop_*() functions should be used for this type.

       GETADDRSBYNAME
	   returns all known addresses for a given name. The lwres_gabn_*()
	   functions should be used for	this type.

       GETNAMEBYADDR
	   return the hostname for the given address. The lwres_gnba_*()
	   functions should be used for	this type.

       lwres_lwpacket_renderheader() transfers the contents of lightweight
       resolver	packet structure lwres_lwpacket_t*pkt in network byte order to
       the lightweight resolver	buffer,	*b.

       lwres_lwpacket_parseheader() performs the converse operation. It
       transfers data in network byte order from buffer	*b to resolver packet
       *pkt. The contents of the buffer	b should correspond to a
       lwres_lwpacket_t.

RETURN VALUES
       Successful calls	to lwres_lwpacket_renderheader() and
       lwres_lwpacket_parseheader() return LWRES_R_SUCCESS. If there is
       insufficient space to copy data between the buffer *b and lightweight
       resolver	packet *pkt both functions return LWRES_R_UNEXPECTEDEND.

AUTHOR
       Internet	Systems	Consortium, Inc.

COPYRIGHT
       Copyright (C) 2000, 2001, 2004, 2005, 2007, 2014-2016, 2018-2020
       Internet	Systems	Consortium, Inc. ("ISC")

ISC				  2007-06-18		       LWRES_PACKET(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | AUTHOR | COPYRIGHT

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