265 lines
11 KiB
C
265 lines
11 KiB
C
/*
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* unbound-event.h - unbound validating resolver public API with events
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*
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* Copyright (c) 2007, NLnet Labs. All rights reserved.
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*
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* This software is open source.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of the NLNET LABS nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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*
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* This file contains the unbound interface for use with user defined
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* pluggable event bases.
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*
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* Use ub_ctx_create_event_ub_base() to create an unbound context that uses
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* the user provided event base API. Then, use the ub_resolve_event call
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* to add DNS resolve queries to the context. Those then run whith the
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* provided event_base, and when they are done you get a function callback.
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*
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* This method does not fork another process or create a thread, the effort
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* is done by the unbound state machines that are connected to the event base.
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*
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* It is also possible to provide a libevent based event base by using
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* ub_ctx_create_event_base(). But you have to use the same libevent that
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* unbound was compiled with, otherwise it wouldn't work, the event and
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* event_base structures would be different.
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*/
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#ifndef _UB_UNBOUND_EVENT_H
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#define _UB_UNBOUND_EVENT_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct ub_ctx;
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struct ub_result;
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struct event_base;
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/** event timeout */
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#define UB_EV_TIMEOUT 0x01
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/** event fd readable */
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#define UB_EV_READ 0x02
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/** event fd writable */
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#define UB_EV_WRITE 0x04
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/** event signal */
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#define UB_EV_SIGNAL 0x08
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/** event must persist */
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#define UB_EV_PERSIST 0x10
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/** magic number to identify this version of the pluggable event api */
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#define UB_EVENT_MAGIC 0x44d74d78
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struct ub_event;
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struct ub_event_base;
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struct timeval;
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/**
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* The Virtual Method Table for and ub_event_base "object"
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*/
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struct ub_event_base_vmt {
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/** Destructor for the ub_event_base object,
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* (not called by libunbound) */
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void (*free)(struct ub_event_base*);
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/** Run the event loop
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* (not called by libunbound when using ub_resolve_event) */
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int (*dispatch)(struct ub_event_base*);
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/** Exit the given event loop */
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int (*loopexit)(struct ub_event_base*, struct timeval*);
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/** Instantiate a new ub_event associated with this event base */
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struct ub_event* (*new_event)(struct ub_event_base*,
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int fd, short bits, void (*cb)(int, short, void*), void* arg);
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/** Instantiate a new signal associated with this event base,
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* (not called by libunbound) */
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struct ub_event* (*new_signal)(struct ub_event_base*, int fd,
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void (*cb)(int, short, void*), void* arg);
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/** Create a new ub_event associated with the given wsaevent,
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* (not called by libunbound) */
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struct ub_event* (*winsock_register_wsaevent)(struct ub_event_base*,
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void* wsaevent, void (*cb)(int, short, void*), void* arg);
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};
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/**
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* A user defined pluggable event base is registered by providing a
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* ub_event_base "object" with the ub_ctx_create_ub_event() function.
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* The magic number must be correct and the Virtual Method Table must be
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* fully equipped providing the event base API to be used by libunbound.
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*/
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struct ub_event_base {
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/** magic must be UB_EVENT_MAGIC (0x44d74d78) */
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unsigned long magic;
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/** Virtual Method Table for ub_event_base */
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struct ub_event_base_vmt* vmt;
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};
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/**
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* The Virtual Method Table for and ub_event "object"
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*/
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struct ub_event_vmt {
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/** Add event bits for this event to fire on.
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* The event will be deactivated before this function is called. */
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void (*add_bits)(struct ub_event*, short);
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/** Configure the event so it will not longer fire on given bits
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* The event will be deactivated before this function is called. */
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void (*del_bits)(struct ub_event*, short);
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/** Change or set the file descriptor on the event
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* The event will be deactivated before this function is called. */
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void (*set_fd)(struct ub_event*, int);
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/** Destructor for the ub_event object */
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void (*free)(struct ub_event*);
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/** Activate the event. The given timeval is an timeout value. */
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int (*add)(struct ub_event*, struct timeval*);
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/** Deactivate the event */
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int (*del)(struct ub_event*);
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/** Reconfigure and activate a timeout event */
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int (*add_timer)(struct ub_event*, struct ub_event_base*,
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void (*cb)(int, short, void*), void* arg, struct timeval*);
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/** Deactivate the timeout event */
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int (*del_timer)(struct ub_event*);
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/** Activate a signal event (not called by libunbound). */
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int (*add_signal)(struct ub_event*, struct timeval*);
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/** Deactivate a signal event (not called by libunbound). */
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int (*del_signal)(struct ub_event*);
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/** Destructor for a ub_event associated with a wsaevent,
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* (not called by libunbound)
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*/
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void (*winsock_unregister_wsaevent)(struct ub_event* ev);
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/** Libunbound will signal the eventloop when a TCP windows socket
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* will block on next read or write (given by the eventbits), to work
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* around edge trigger event behaviour of select on windows with TCP.
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*/
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void (*winsock_tcp_wouldblock)(struct ub_event*, int eventbit);
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};
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/**
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* An "object" comprising a user defined pluggable event.
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* The magic number must be correct and the Virtual Method Table must be
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* fully equipped providing the ub_event API to be used by libunbound.
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*/
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struct ub_event {
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/** magic must be UB_EVENT_MAGIC (0x44d74d78) */
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unsigned long magic;
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/** Virtual Method Table for ub_event */
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struct ub_event_vmt* vmt;
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};
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typedef void (*ub_event_callback_type)(void*, int, void*, int, int, char*);
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/**
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* Create a resolving and validation context.
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* The information from /etc/resolv.conf and /etc/hosts is not utilised by
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* default. Use ub_ctx_resolvconf and ub_ctx_hosts to read them.
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* @param base: the pluggable event base that the caller has created.
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* The unbound context uses this event base.
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* @return a new context. default initialisation.
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* returns NULL on error.
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* You must use ub_resolve_event with this context.
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* Do not call ub_ctx_async, ub_poll, ub_wait, ub_process, this is all done
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* with the event_base. Setup the options you like with the other functions.
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*/
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struct ub_ctx* ub_ctx_create_ub_event(struct ub_event_base* base);
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/**
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* Create a resolving and validation context.
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* The information from /etc/resolv.conf and /etc/hosts is not utilised by
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* default. Use ub_ctx_resolvconf and ub_ctx_hosts to read them.
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* You have to use the same libevent that unbound was compiled with,
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* otherwise it wouldn't work, the event and event_base structures would
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* be different.
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* @param base: the event base that the caller has created. The unbound
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* context uses this event base.
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* @return a new context. default initialisation.
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* returns NULL on error.
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* You must use ub_resolve_event with this context.
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* Do not call ub_ctx_async, ub_poll, ub_wait, ub_process, this is all done
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* with the event_base. Setup the options you like with the other functions.
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*/
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struct ub_ctx* ub_ctx_create_event(struct event_base* base);
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/**
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* Set a new libevent event_base on a context created with ub_ctx_create_event.
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* You have to use the same libevent that unbound was compiled with,
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* otherwise it wouldn't work, the event and event_base structures would
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* be different.
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* Any outbound queries will be canceled.
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* @param ctx the ub_ctx to update. Must have been created with ub_ctx_create_event
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* @param base the new event_base to attach to the ctx
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* @return 0 if OK, else error
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*/
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int ub_ctx_set_event(struct ub_ctx* ctx, struct event_base* base);
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/**
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* Perform resolution and validation of the target name.
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* Asynchronous, after a while, the callback will be called with your
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* data and the result. Uses the event_base user installed by creating the
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* context with ub_ctx_create_event().
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* @param ctx: context with event_base in it.
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* The context is finalized, and can no longer accept all config changes.
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* @param name: domain name in text format (a string).
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* @param rrtype: type of RR in host order, 1 is A.
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* @param rrclass: class of RR in host order, 1 is IN (for internet).
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* @param mydata: this data is your own data (you can pass NULL),
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* and is passed on to the callback function.
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* @param callback: this is called on completion of the resolution.
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* It is called as:
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* void callback(void* mydata, int rcode, void* packet, int packet_len,
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* int sec, char* why_bogus)
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* with mydata: the same as passed here, you may pass NULL,
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* with rcode: 0 on no error, nonzero for mostly SERVFAIL situations,
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* this is a DNS rcode.
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* with packet: a buffer with DNS wireformat packet with the answer.
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* do not inspect if rcode != 0.
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* do not write or free the packet buffer, it is used internally
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* in unbound (for other callbacks that want the same data).
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* with packet_len: length in bytes of the packet buffer.
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* with sec: 0 if insecure, 1 if bogus, 2 if DNSSEC secure.
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* with why_bogus: text string explaining why it is bogus (or NULL).
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* These point to buffers inside unbound; do not deallocate the packet or
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* error string.
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*
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* If an error happens during processing, your callback will be called
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* with error set to a nonzero value (and result==NULL).
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* For localdata (etc/hosts) the callback is called immediately, before
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* resolve_event returns, async_id=0 is returned.
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* @param async_id: if you pass a non-NULL value, an identifier number is
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* returned for the query as it is in progress. It can be used to
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* cancel the query.
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* @return 0 if OK, else error.
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*/
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int ub_resolve_event(struct ub_ctx* ctx, const char* name, int rrtype,
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int rrclass, void* mydata, ub_event_callback_type callback,
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int* async_id);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _UB_UNBOUND_H */
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