1 /* 2 * unbound-event.h - unbound validating resolver public API with events 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains the unbound interface for use with libevent. 40 * You have to use the same libevent that unbound was compiled with, 41 * otherwise it wouldn't work, the event and event_base structures would 42 * be different. If unbound is compiled without libevent support then 43 * this header file is not supposed to be installed on the system. 44 * 45 * Use ub_ctx_create_event_base() to create an unbound context that uses 46 * the event base that you have made. Then, use the ub_resolve_event call 47 * to add DNS resolve queries to the context. Those then run when you 48 * call event_dispatch() on your event_base, and when they are done you 49 * get a function callback. 50 * 51 * This method does not fork another process or create a thread, the effort 52 * is done by the unbound state machines that are connected to the event_base. 53 */ 54 #ifndef _UB_UNBOUND_EVENT_H 55 #define _UB_UNBOUND_EVENT_H 56 57 #ifdef __cplusplus 58 extern "C" { 59 #endif 60 61 struct ub_ctx; 62 struct ub_result; 63 struct event_base; 64 65 typedef void (*ub_event_callback_t)(void*, int, void*, int, int, char*); 66 67 /** 68 * Create a resolving and validation context. 69 * The information from /etc/resolv.conf and /etc/hosts is not utilised by 70 * default. Use ub_ctx_resolvconf and ub_ctx_hosts to read them. 71 * @param base: the event base that the caller has created. The unbound 72 * context uses this event base. 73 * @return a new context. default initialisation. 74 * returns NULL on error. 75 * You must use ub_resolve_event with this context. 76 * Do not call ub_ctx_async, ub_poll, ub_wait, ub_process, this is all done 77 * with the event_base. Setup the options you like with the other functions. 78 */ 79 struct ub_ctx* ub_ctx_create_event(struct event_base* base); 80 81 /** 82 * Set a new event_base on a context created with ub_ctx_create_event. 83 * Any outbound queries will be canceled. 84 * @param ctx the ub_ctx to update. Must have been created with ub_ctx_create_event 85 * @param base the new event_base to attach to the ctx 86 * @return 0 if OK, else error 87 */ 88 int ub_ctx_set_event(struct ub_ctx* ctx, struct event_base* base); 89 90 /** 91 * Perform resolution and validation of the target name. 92 * Asynchronous, after a while, the callback will be called with your 93 * data and the result. Uses the event_base user installed by creating the 94 * context with ub_ctx_create_event(). 95 * @param ctx: context with event_base in it. 96 * The context is finalized, and can no longer accept all config changes. 97 * @param name: domain name in text format (a string). 98 * @param rrtype: type of RR in host order, 1 is A. 99 * @param rrclass: class of RR in host order, 1 is IN (for internet). 100 * @param mydata: this data is your own data (you can pass NULL), 101 * and is passed on to the callback function. 102 * @param callback: this is called on completion of the resolution. 103 * It is called as: 104 * void callback(void* mydata, int rcode, void* packet, int packet_len, 105 * int sec, char* why_bogus) 106 * with mydata: the same as passed here, you may pass NULL, 107 * with rcode: 0 on no error, nonzero for mostly SERVFAIL situations, 108 * this is a DNS rcode. 109 * with packet: a buffer with DNS wireformat packet with the answer. 110 * do not inspect if rcode != 0. 111 * do not write or free the packet buffer, it is used internally 112 * in unbound (for other callbacks that want the same data). 113 * with packet_len: length in bytes of the packet buffer. 114 * with sec: 0 if insecure, 1 if bogus, 2 if DNSSEC secure. 115 * with why_bogus: text string explaining why it is bogus (or NULL). 116 * These point to buffers inside unbound; do not deallocate the packet or 117 * error string. 118 * 119 * If an error happens during processing, your callback will be called 120 * with error set to a nonzero value (and result==NULL). 121 * For localdata (etc/hosts) the callback is called immediately, before 122 * resolve_event returns, async_id=0 is returned. 123 * @param async_id: if you pass a non-NULL value, an identifier number is 124 * returned for the query as it is in progress. It can be used to 125 * cancel the query. 126 * @return 0 if OK, else error. 127 */ 128 int ub_resolve_event(struct ub_ctx* ctx, const char* name, int rrtype, 129 int rrclass, void* mydata, ub_event_callback_t callback, int* async_id); 130 131 #ifdef __cplusplus 132 } 133 #endif 134 135 #endif /* _UB_UNBOUND_H */ 136