/*
* unbound-event.h - unbound validating resolver public API with events
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* This file contains the unbound interface for use with libevent.
* You have to use the same libevent that unbound was compiled with,
* otherwise it wouldn't work, the event and event_base structures would
* be different. If unbound is compiled without libevent support then
* this header file is not supposed to be installed on the system.
*
* Use ub_ctx_create_event_base() to create an unbound context that uses
* the event base that you have made. Then, use the ub_resolve_event call
* to add DNS resolve queries to the context. Those then run when you
* call event_dispatch() on your event_base, and when they are done you
* get a function callback.
*
* This method does not fork another process or create a thread, the effort
* is done by the unbound state machines that are connected to the event_base.
*/
#ifndef _UB_UNBOUND_EVENT_H
#define _UB_UNBOUND_EVENT_H
#ifdef __cplusplus
extern "C" {
#endif
struct ub_ctx;
struct ub_result;
struct event_base;
typedef void (*ub_event_callback_t)(void*, int, void*, int, int, char*);
/**
* Create a resolving and validation context.
* The information from /etc/resolv.conf and /etc/hosts is not utilised by
* default. Use ub_ctx_resolvconf and ub_ctx_hosts to read them.
* @param base: the event base that the caller has created. The unbound
* context uses this event base.
* @return a new context. default initialisation.
* returns NULL on error.
* You must use ub_resolve_event with this context.
* Do not call ub_ctx_async, ub_poll, ub_wait, ub_process, this is all done
* with the event_base. Setup the options you like with the other functions.
*/
struct ub_ctx* ub_ctx_create_event(struct event_base* base);
/**
* Set a new event_base on a context created with ub_ctx_create_event.
* Any outbound queries will be canceled.
* @param ctx the ub_ctx to update. Must have been created with ub_ctx_create_event
* @param base the new event_base to attach to the ctx
* @return 0 if OK, else error
*/
int ub_ctx_set_event(struct ub_ctx* ctx, struct event_base* base);
/**
* Perform resolution and validation of the target name.
* Asynchronous, after a while, the callback will be called with your
* data and the result. Uses the event_base user installed by creating the
* context with ub_ctx_create_event().
* @param ctx: context with event_base in it.
* The context is finalized, and can no longer accept all config changes.
* @param name: domain name in text format (a string).
* @param rrtype: type of RR in host order, 1 is A.
* @param rrclass: class of RR in host order, 1 is IN (for internet).
* @param mydata: this data is your own data (you can pass NULL),
* and is passed on to the callback function.
* @param callback: this is called on completion of the resolution.
* It is called as:
* void callback(void* mydata, int rcode, void* packet, int packet_len,
* int sec, char* why_bogus)
* with mydata: the same as passed here, you may pass NULL,
* with rcode: 0 on no error, nonzero for mostly SERVFAIL situations,
* this is a DNS rcode.
* with packet: a buffer with DNS wireformat packet with the answer.
* do not inspect if rcode != 0.
* do not write or free the packet buffer, it is used internally
* in unbound (for other callbacks that want the same data).
* with packet_len: length in bytes of the packet buffer.
* with sec: 0 if insecure, 1 if bogus, 2 if DNSSEC secure.
* with why_bogus: text string explaining why it is bogus (or NULL).
* These point to buffers inside unbound; do not deallocate the packet or
* error string.
*
* If an error happens during processing, your callback will be called
* with error set to a nonzero value (and result==NULL).
* For localdata (etc/hosts) the callback is called immediately, before
* resolve_event returns, async_id=0 is returned.
* @param async_id: if you pass a non-NULL value, an identifier number is
* returned for the query as it is in progress. It can be used to
* cancel the query.
* @return 0 if OK, else error.
*/
int ub_resolve_event(struct ub_ctx* ctx, const char* name, int rrtype,
int rrclass, void* mydata, ub_event_callback_t callback, int* async_id);
#ifdef __cplusplus
}
#endif
#endif /* _UB_UNBOUND_H */
