$Id: lwres,v 1.1 2000/02/29 20:10:49 explorer Exp $

General design:

The lwres library converts structures into wire-format packets for

transmission, and unmarshalls them on receive.

Marshalling and unmarshalling:

Each structure will have two functions defined, one to take a

wire-format packet and convert it into a structure, and another to

take a structure and convert it into a wire-format packet. There

is a structure cleanup function that will take the unmarshalled

structure and free any dynamically allocated elements.

Wire formats:

All integer values are in network byte order.

All addresses are in network byte order. That is, they are directly

usable and do not need to be byte swapped, at least for ipv4 and ipv6.

All character strings are prefixed with a length, and are NUL

terminated C strings. This is a concession for structure handling on

the receive side, and allows a mapping structure to point to data

contained in the actual receive buffer, eliminating copying.

NOOP (aka ping) packet format:

lwres_lwpacket_t header;

isc_uint16_t datalength;

< datalength bytes >

The server simply returns the entire data region in the reply. This

allows the client to determine if the server is operational.

GETADDRSBYNAME:

lwres_lwpacket_t header;

isc_uint16_t naliases;

isc_uint16_t naddrs;

isc_uint16_t real_name_len;

< real_name_len bytes of name >

isc_uint8_t \0

< naliases of

isc_uint16_t len;

< len bytes of name >

isc_uint8_t \0

>

< naddrs of

isc_uint32_t family;

isc_uint16_t len;

< len bytes of address >

>

GETNAMEBYADDR:

lwres_lwpacket_t header;

isc_uint16_t naliases;

isc_uint16_t real_name_len;

< real_name_len bytes of name >

isc_uint8_t \0

< naliases of

isc_uint16_t len;

< len bytes of name >

isc_uint8_t \0

>