lwres_lwpacket_parseheader

LWRES_PACKET(3)                                                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); .SH "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)