LIBRARY

DNS Resolver library (libgetdns, -lgetdns)

SYNOPSIS

#include <getdns.h>

getdns_return_t
getdns_address (getdns_context *context,

const char *name,
getdns_dict *extensions,
void *userarg,
getdns_transaction_t *transaction_id,
getdns_callback_t callbackfn)

getdns_return_t
getdns_address_sync (getdns_context *context,

const char *name,
getdns_dict *extensions,
getdns_dict **response)

DESCRIPTION

The getdns_address(3) and getdns_address_sync functions provide public entry points into the getdns API library to retrieve the address given a host name. They always returns both IPv4 and IPv6 addresses. This function will use all of the namespaces from the context (to better emulate getaddrinfo (3)).

context

A pointer to the previously created DNS context that is to be used with this DNS request. see getdns_context (3)

name

the host name to resolve to an address (note that an IP address is considered invalid)

extensions

extensions for this request, NULL if no extensions, see libgetdns (3) for a detailed description of extensions

userarg

returned to the callback function untouched, can be NULL

transaction_id

populated by the API and used to identify the callback (for example to getdns_cancel_callback), can be NULL, set to 0 if the function fails

callbackfn

non-NULL pointer to a callback function defined by the application, typically used to process the response. Only the asynchronous signature accepts a callback function, the synchronous signature does not include a callback. See libgetdns (3) for a more detailed discussion of callback functions.

response

A getdns_dict type is returned in response and always contains at least three names: replies_full (a list containing the DNS response as binary data), replies_tree (a list containing the parsed DNS response data) and status (an int). The storage associated with this must be freed by a call to getdns_free_sync_request_memory (3).

RETURN VALUES

Upon successful completion the functions return GETDNS_RETURN_GOOD , otherwise the following error values are returned:

GETDNS_RETURN_BAD_CONTEXT if the context pointer is invalid or the context has internal deficiencies

GETDNS_RETURN_BAD_DOMAIN_NAME if the domain name passed to the function is invalid

GETDNS_RETURN_EXTENSION_MISFORMAT if the data type specified in one or more of the extensions does not match the specifications

GETDNS_RETURN_GENERIC_ERROR if some problem was encountered in the function not addressed by one of the more specific return codes

GETDNS_RETURN_INVALID PARAMETER if one or more parameters has an invalid value

GETDNS_RETURN_MEMORY_ERROR if unable to allocate the memory required

GETDNS_RETURN_NO_SUCH_EXTENSION if one or more of the strings specified in the extensions are not valid

The values of status included in the response parameter are:

GETDNS_RESPSTATUS_GOOD if at least one response was returned

GETDNS_RESPSTATUS_NO_NAME if queries for the name yielded all negative responses

GETDNS_RESPSTATUS_ALL_TIMEOUT if all queries for the name timed out

GETDNS_RESPSTATUS_NO_SECURE_ANSWERS if only secure replies accepted (per context) and at least one response was received but no DNS responses were secure through DNSSEC

For a more detailed explanation of the response object see libgetdns (3)

EXAMPLES

TBD

FILES

/etc/hosts
/etc/resolv.conf