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LWRES_RESUTIL(3) | BIND9 | LWRES_RESUTIL(3) |
NAME¶
lwres_string_parse, lwres_addr_parse, lwres_getaddrsbyname, lwres_getnamebyaddr - lightweight resolver utility functionsSYNOPSIS¶
#include <lwres/lwres.h>
lwres_result_t
lwres_string_parse(lwres_buffer_t *b,
char **c,
lwres_uint16_t *len);
lwres_result_t
lwres_addr_parse(lwres_buffer_t *b,
lwres_addr_t *addr);
lwres_result_t
lwres_getaddrsbyname(lwres_context_t *ctx,
const char *name,
lwres_uint32_t addrtypes,
lwres_gabnresponse_t **structp);
lwres_result_t
lwres_getnamebyaddr(lwres_context_t *ctx,
lwres_uint32_t addrtype,
lwres_uint16_t addrlen,
const unsigned char *addr,
lwres_gnbaresponse_t **structp);
DESCRIPTION¶
lwres_string_parse() retrieves a DNS-encoded string starting the current pointer of lightweight resolver buffer b: i.e. b->current. When the function returns, the address of the first byte of the encoded string is returned via *c and the length of that string is given by *len. The buffer's current pointer is advanced to point at the character following the string length, the encoded string, and the trailing NULL character. lwres_addr_parse() extracts an address from the buffer b. The buffer's current pointer b->current is presumed to point at an encoded address: the address preceded by a 32-bit protocol family identifier and a 16-bit length field. The encoded address is copied to addr->address and addr->length indicates the size in bytes of the address that was copied. b->current is advanced to point at the next byte of available data in the buffer following the encoded address. lwres_getaddrsbyname() and lwres_getnamebyaddr() use the lwres_gnbaresponse_t structure defined below:typedef struct { lwres_uint32_t flags; lwres_uint16_t naliases; lwres_uint16_t naddrs; char *realname; char **aliases; lwres_uint16_t realnamelen; lwres_uint16_t *aliaslen; lwres_addrlist_t addrs; void *base; size_t baselen; } lwres_gabnresponse_t;
RETURN VALUES¶
Successful calls to lwres_string_parse() and lwres_addr_parse() return LWRES_R_SUCCESS. Both functions return LWRES_R_FAILURE if the buffer is corrupt or LWRES_R_UNEXPECTEDEND if the buffer has less space than expected for the components of the encoded string or address. lwres_getaddrsbyname() returns LWRES_R_SUCCESS on success and it returns LWRES_R_NOTFOUND if the hostname name could not be found. LWRES_R_SUCCESS is returned by a successful call to lwres_getnamebyaddr(). Both lwres_getaddrsbyname() and lwres_getnamebyaddr() return LWRES_R_NOMEMORY when memory allocation requests fail and LWRES_R_UNEXPECTEDEND if the buffers used for sending queries and receiving replies are too small.SEE ALSO¶
lwres_buffer(3), lwres_gabn(3).COPYRIGHT¶
Copyright © 2004, 2005, 2007 Internet Systems Consortium, Inc. ("ISC")June 30, 2000 | BIND9 |