getdns/doc/getdns_general.3.in

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.TH getdns_general 3 "@date@" "getdns @version@" getdns
.SH NAME
.B getdns_general, 
.B getdns_general_sync
-- do a getdns DNS lookup

.SH LIBRARY
DNS Resolver library (libgetdns, \-lgetdns)

.SH SYNOPSIS
#include <getdns.h>

getdns_return_t 
.br
.B getdns_general
(getdns_context *context,
.RS 3
const char *name,
.br
uint16_t request_type
.br
getdns_dict *extensions,
.br
void *userarg,
.br
getdns_transaction_t *transaction_id,
.br
getdns_callback_t callbackfn)
.RE

getdns_return_t 
.br
.B getdns_general_sync
(getdns_context *context,
.RS 3
const char *name,
.br
uint16_t request_type
.br
getdns_dict *extensions,
.br
getdns_dict **response)
.RE

.SH DESCRIPTION

.LP
The getdns_general(3) and getdns_general_sync functions provide public entry
points into the getdns API library to retrieve any valid responses to a query
from the DNS (note that other namespaces in the context are not used).   Most
typical use cases for applications are probably satisfied via calls to
getdns_address(3) which would replace getaddrinfo(3).

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

.HP 3
.I name
The ASCII-based domain name looked up as a string. This can also be an
IPv4 or IPv6 address for request types that take addresses instead of domain
names, such as PTR. The values here follow the rules in section 2.1 of RFC 4343
to allow non-ASCII octets and special characters in labels.

.HP 3
.I request_type
Specifies the RRtype for the query; the RRtype numbers are listed in the IANA registry. For example, to get the NS records, request_type would be 2. The API also has defined macros for most of the RRtypes by name; the definition names all start with "GETDNS_RRTYPE_". For example, to get the NS records, you can also set the request_type to GETDNS_RRTYPE_NS.

.HP 3
.I extensions
extensions for this request, NULL if no extensions, see libgetnds (3) for a detailed description of extensions

.HP 3
.I userarg
returned to the callback function untouched, can be NULL

.HP 3
.I 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

.HP 3
.I 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.

.HP 3
.I 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).

.HP
.SH "RETURN VALUES"

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

.LP
.B GETDNS_RETURN_BAD_CONTEXT 
if the context pointer is invalid or the context has internal deficiencies
.LP
.B GETDNS_RETURN_BAD_DOMAIN_NAME
if the domain name passed to the function is invalid
.LP
.B GETDNS_RETURN_EXTENSION_MISFORMAT
if the data type specified in one or more of the extensions does not match the specifications
.LP
.B GETDNS_RETURN_GENERIC_ERROR
if some problem was encountered in the function not addressed by one of the more
specific return codes
.LP
.B GETDNS_RETURN_INVALID PARAMETER 
if one or more parameters has an invalid value
.LP
.B GETDNS_RETURN_MEMORY_ERROR
if unable to allocate the memory required
.LP
.B 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:

.LP
.B GETDNS_RESPSTATUS_GOOD
if at least one response was returned
.LP
.B GETDNS_RESPSTATUS_NO_NAME
if queries for the name yielded all negative responses
.LP
.B GETDNS_RESPSTATUS_ALL_TIMEOUT
if all queries for the name timed out
.LP
.B 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

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

.SH REQUEST TYPES

This is a list of the most common request types, a full list of request types in more detail is available at http://www.iana.org/assignments/dns-parameters/dns-parameters.xml

.RS 3
.TP 11
.B A
Host address
.TP 
.B AAAA
IPv6 address
.TP
.B CAA
Certificate Authority Authorization
.TP
.B CNAME
Canonical name for an alias
.TP
.B DLV
DNSSEC lookaside validation
.TP
.B DNAME
DNAME
.TP
.B DS
Delegation signer
.TP
.B HINFO
Host information
.TP
.B KEY
Security key
.TP
.B MINFO
Mailbox or mail list information
.TP
.B MX
Mail exchange
.TP
.B NS
Authoritative name server
.TP
.B NSEC
Next secure record
.TP
.B NSEC3
Next secure record (hashed)
.TP
.B NSEC3PARAM
NSEC3PARAM
.TP
.B PTR
Domain name pointer
.TP
.B RRSIG
Signature for a record set
.TP
.B SIG
Security signature
.TP
.B SOA
Marks the start of a zone of authority
.TP
.B SRV
Server selection
.TP
.B TA
DNSSEC trust authorities
.TP
.B TKEY
Transaction key
.TP
.B TLSA
TLSA
.TP
.B TSIG
Transaction signature
.TP
.B TXT
Text strings
.RE

.SH EXAMPLES

TBD

.SH FILES
.br
/etc/hosts
.br
/etc/resolv.conf

.SH SEE ALSO
.BR libgetdns (3),
.BR getdns_address (3),
.BR getdns_context (3),
.BR getdns_free_sync_request_memory (3), 
.BR getdns_hostname (3),
.BR getdns_service (3),