CONTENTS

SYNOPSIS

lwres_result_t lwres_gnbarequest_render(lwres_context_t *ctx, lwres_gnbarequest_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);

lwres_result_t lwres_gnbaresponse_render(lwres_context_t *ctx, lwres_gnbaresponse_t *req, lwres_lwpacket_t *pkt, lwres_buffer_t *b);

lwres_result_t lwres_gnbarequest_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbarequest_t **structp);

lwres_result_t lwres_gnbaresponse_parse(lwres_context_t *ctx, lwres_buffer_t *b, lwres_lwpacket_t *pkt, lwres_gnbaresponse_t **structp);

void lwres_gnbaresponse_free(lwres_context_t *ctx, lwres_gnbaresponse_t **structp);

These are low-level routines for creating and parsing lightweight resolver address-to-name lookup request and response messages.

There are four main functions for the getnamebyaddr opcode. One render function converts a getnamebyaddr request structure — lwres_gnbarequest_t — to the lightweight resolver’s canonical format. It is complemented by a parse function that converts a packet in this canonical format to a getnamebyaddr request structure. Another render function converts the getnamebyaddr response structure — lwres_gnbaresponse_t to the canonical format. This is complemented by a parse function which converts a packet in canonical format to a getnamebyaddr response structure.

These structures are defined in lwres/lwres.h. They are shown below.

#define LWRES_OPCODE_GETNAMEBYADDR 0x00010002U

typedef struct {
lwres_uint32_t flags;
lwres_addr_t addr;
} lwres_gnbarequest_t;

typedef struct {
lwres_uint32_t flags;
lwres_uint16_t naliases;
char *realname;
char**aliases;
lwres_uint16_t realnamelen;
lwres_uint16_t *aliaslen;
void *base;
size_tbaselen;
} lwres_gnbaresponse_t;

lwres_gnbarequest_render() uses resolver context ctx to convert getnamebyaddr request structure req to canonical format. The packet header structure pkt is initialised and transferred to buffer b. The contents of *req are then appended to the buffer in canonical format. lwres_gnbaresponse_render() performs the same task, except it converts a getnamebyaddr response structure lwres_gnbaresponse_t to the lightweight resolver’s canonical format.

lwres_gnbarequest_parse() uses context ctx to convert the contents of packet pkt to a lwres_gnbarequest_t structure. Buffer b provides space to be used for storing this structure. When the function succeeds, the resulting lwres_gnbarequest_t is made available through *structp. lwres_gnbaresponse_parse() offers the same semantics as lwres_gnbarequest_parse() except it yields a lwres_gnbaresponse_t structure.