LWRES_PACKET(3)               BIND9               LWRES_PACKET(3)



NAME
       lwres_lwpacket_renderheader, lwres_lwpacket_parseheader -
       lightweight resolver packet handling functions

SYNOPSIS
       #include 

       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 {
               lwres_uint32_t          length;
               lwres_uint16_t          version;
               lwres_uint16_t          pktflags;
               lwres_uint32_t          serial;
               lwres_uint32_t          opcode;
               lwres_uint32_t          result;
               lwres_uint32_t          recvlength;
               lwres_uint16_t          authtype;
               lwres_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 wit 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.



BIND9                      Jun 30, 2000           LWRES_PACKET(3)