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/*
This file is part of GNUnet
(C) 2012 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 2, or (at your
option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
/**
* @file include/gnunet_dns_service-new.h
* @brief API to access the DNS service.
* @author Christian Grothoff
*/
#ifndef GNUNET_DNS_SERVICE_NEW_H
#define GNUNET_DNS_SERVICE_NEW_H
#include "gnunet_common.h"
#include "gnunet_util_lib.h"
/**
* A few common DNS types.
*/
#define GNUNET_DNS_TYPE_A 1
#define GNUNET_DNS_TYPE_NS 2
#define GNUNET_DNS_TYPE_CNAME 5
#define GNUNET_DNS_TYPE_SOA 6
#define GNUNET_DNS_TYPE_PTR 12
#define GNUNET_DNS_TYPE_MX 15
#define GNUNET_DNS_TYPE_TXT 16
#define GNUNET_DNS_TYPE_AAAA 28
#define GNUNET_DNS_TYPE_IXFR 251
#define GNUNET_DNS_TYPE_AXFR 252
/**
* A few common DNS classes (ok, only one is common, but I list a
* couple more to make it clear what we're talking about here).
*/
#define GNUNET_DNS_CLASS_INTERNET 1
#define GNUNET_DNS_CLASS_CHAOS 3
#define GNUNET_DNS_CLASS_HESIOD 4
/**
* Opaque DNS handle
*/
struct GNUNET_DNS_Handle;
/**
* Handle to identify an individual DNS request.
*/
struct GNUNET_DNS_RequestHandle;
/**
* Signature of a function that is called whenever the DNS service
* encounters a DNS request and needs to do something with it. The
* function has then the chance to generate or modify the response by
* calling one of the three "GNUNET_DNS_request_*" continuations.
*
* When a request is intercepted, this function is called first to
* give the client a chance to do the complete address resolution;
* "rdata" will be NULL for this first call for a DNS request, unless
* some other client has already filled in a response.
*
* If multiple clients exist, all of them are called before the global
* DNS. The global DNS is only called if all of the clients'
* functions call GNUNET_DNS_request_forward. Functions that call
* GNUNET_DNS_request_forward will be called again before a final
* response is returned to the application. If any of the clients'
* functions call GNUNET_DNS_request_drop, the response is dropped.
*
* @param cls closure
* @param name name of the node to which the record pertains
* @param dns_type type of RR
* @param dns_class class code
* @param dns_ttl seconds that the RR stays valid, can be updated
* @param rdata_length size of rdata, can be updated
* @param rdata record data, can be updated
*/
typedef void (*GNUNET_DNS_RequestHandler)(void *cls,
struct GNUNET_DNS_RequestHandle *rh,
const char *name,
uint16_t dns_type,
uint16_t dns_class,
uint32_t dns_ttl,
uint16_t rdata_length,
const char *rdata);
/**
* If a GNUNET_DNS_RequestHandler calls this function, the request is
* given to other clients or the global DNS for resolution. Once a
* global response has been obtained, the request handler is AGAIN
* called to give it a chance to observe and modify the response after
* the "normal" resolution. It is not legal for the request handler
* to call this function if a response is already present.
*
* @param rh request that should now be forwarded
*/
void
GNUNET_DNS_request_forward (struct GNUNET_DNS_RequestHandle *rh);
/**
* If a GNUNET_DNS_RequestHandler calls this function, the request is
* to be dropped and no response should be generated.
*
* @param rh request that should now be dropped
*/
void
GNUNET_DNS_request_drop (struct GNUNET_DNS_RequestHandle *rh);
/**
* If a GNUNET_DNS_RequestHandler calls this function, the request is supposed to
* be answered with the data provided to this call (with the modifications the function might have made).
*
* @param rh request that should now be answered
* @param dns_ttl seconds that the RR stays valid, can be updated
* @param rdata_length size of rdata, can be updated
* @param rdata record data, can be updated
*/
void
GNUNET_DNS_request_answer (struct GNUNET_DNS_RequestHandle *rh,
uint32_t dns_ttl,
uint16_t rdata_length,
char *rdata);
/**
* Connect to the service-dns
*
* @param cfg configuration to use
* @param rh function to call with DNS requests
* @param rh_cls closure to pass to rh
* @return DNS handle
*/
struct GNUNET_DNS_Handle *
GNUNET_DNS_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
GNUNET_DNS_RequestHandler rh,
void *rh_cls);
/**
* Disconnect from the DNS service.
*
* @param dh DNS handle
*/
void
GNUNET_DNS_disconnect (struct GNUNET_DNS_Handle *dh);
#endif
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