/*
- * Copyright (c) 200
6 Niels Provos <provos@citi.umich.edu>
+ * Copyright (c) 200
8 Niels Provos <provos@citi.umich.edu>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
+#ifndef _EVDNS_H_
+#define _EVDNS_H_
-/*
- * The original DNS code is due to Adam Langley with heavy
- * modifications by Nick Mathewson. Adam put his DNS software in the
- * public domain. You can find his original copyright below. Please,
- * aware that the code as part of libevent is governed by the 3-clause
- * BSD license above.
- *
- * This software is Public Domain. To view a copy of the public domain dedication,
- * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
- * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
- *
- * I ask and expect, but do not require, that all derivative works contain an
- * attribution similar to:
- * Parts developed by Adam Langley <agl@imperialviolet.org>
- *
- * You may wish to replace the word "Parts" with something else depending on
- * the amount of original code.
- *
- * (Derivative works does not include programs which link against, run or include
- * the source verbatim in their source distributions)
- */
-
-/** @file evdns.h
- *
- * Welcome, gentle reader
- *
- * Async DNS lookups are really a whole lot harder than they should be,
- * mostly stemming from the fact that the libc resolver has never been
- * very good at them. Before you use this library you should see if libc
- * can do the job for you with the modern async call getaddrinfo_a
- * (see http://www.imperialviolet.org/page25.html#e498). Otherwise,
- * please continue.
- *
- * This code is based on libevent and you must call event_init before
- * any of the APIs in this file. You must also seed the OpenSSL random
- * source if you are using OpenSSL for ids (see below).
- *
- * This library is designed to be included and shipped with your source
- * code. You statically link with it. You should also test for the
- * existence of strtok_r and define HAVE_STRTOK_R if you have it.
- *
- * The DNS protocol requires a good source of id numbers and these
- * numbers should be unpredictable for spoofing reasons. There are
- * three methods for generating them here and you must define exactly
- * one of them. In increasing order of preference:
- *
- * DNS_USE_GETTIMEOFDAY_FOR_ID:
- * Using the bottom 16 bits of the usec result from gettimeofday. This
- * is a pretty poor solution but should work anywhere.
- * DNS_USE_CPU_CLOCK_FOR_ID:
- * Using the bottom 16 bits of the nsec result from the CPU's time
- * counter. This is better, but may not work everywhere. Requires
- * POSIX realtime support and you'll need to link against -lrt on
- * glibc systems at least.
- * DNS_USE_OPENSSL_FOR_ID:
- * Uses the OpenSSL RAND_bytes call to generate the data. You must
- * have seeded the pool before making any calls to this library.
- *
- * The library keeps track of the state of nameservers and will avoid
- * them when they go down. Otherwise it will round robin between them.
- *
- * Quick start guide:
- * #include "evdns.h"
- * void callback(int result, char type, int count, int ttl,
- * void *addresses, void *arg);
- * evdns_resolv_conf_parse(DNS_OPTIONS_ALL, "/etc/resolv.conf");
- * evdns_resolve("www.hostname.com", 0, callback, NULL);
- *
- * When the lookup is complete the callback function is called. The
- * first argument will be one of the DNS_ERR_* defines in evdns.h.
- * Hopefully it will be DNS_ERR_NONE, in which case type will be
- * DNS_IPv4_A, count will be the number of IP addresses, ttl is the time
- * which the data can be cached for (in seconds), addresses will point
- * to an array of uint32_t's and arg will be whatever you passed to
- * evdns_resolve.
- *
- * Searching:
- *
- * In order for this library to be a good replacement for glibc's resolver it
- * supports searching. This involves setting a list of default domains, in
- * which names will be queried for. The number of dots in the query name
- * determines the order in which this list is used.
- *
- * Searching appears to be a single lookup from the point of view of the API,
- * although many DNS queries may be generated from a single call to
- * evdns_resolve. Searching can also drastically slow down the resolution
- * of names.
- *
- * To disable searching:
- * 1. Never set it up. If you never call evdns_resolv_conf_parse or
- * evdns_search_add then no searching will occur.
- *
- * 2. If you do call evdns_resolv_conf_parse then don't pass
- * DNS_OPTION_SEARCH (or DNS_OPTIONS_ALL, which implies it).
- *
- * 3. When calling evdns_resolve, pass the DNS_QUERY_NO_SEARCH flag.
- *
- * The order of searches depends on the number of dots in the name. If the
- * number is greater than the ndots setting then the names is first tried
- * globally. Otherwise each search domain is appended in turn.
- *
- * The ndots setting can either be set from a resolv.conf, or by calling
- * evdns_search_ndots_set.
- *
- * For example, with ndots set to 1 (the default) and a search domain list of
- * ["myhome.net"]:
- * Query: www
- * Order: www.myhome.net, www.
- *
- * Query: www.abc
- * Order: www.abc., www.abc.myhome.net
- *
- * Internals:
- *
- * Requests are kept in two queues. The first is the inflight queue. In
- * this queue requests have an allocated transaction id and nameserver.
- * They will soon be transmitted if they haven't already been.
- *
- * The second is the waiting queue. The size of the inflight ring is
- * limited and all other requests wait in waiting queue for space. This
- * bounds the number of concurrent requests so that we don't flood the
- * nameserver. Several algorithms require a full walk of the inflight
- * queue and so bounding its size keeps thing going nicely under huge
- * (many thousands of requests) loads.
- *
- * If a nameserver loses too many requests it is considered down and we
- * try not to use it. After a while we send a probe to that nameserver
- * (a lookup for google.com) and, if it replies, we consider it working
- * again. If the nameserver fails a probe we wait longer to try again
- * with the next probe.
- */
-
-#ifndef EVENTDNS_H
-#define EVENTDNS_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/* For integer types. */
-#include <event2/util.h>
-
-/** Error codes 0-5 are as described in RFC 1035. */
-#define DNS_ERR_NONE 0
-/** The name server was unable to interpret the query */
-#define DNS_ERR_FORMAT 1
-/** The name server was unable to process this query due to a problem with the
- * name server */
-#define DNS_ERR_SERVERFAILED 2
-/** The domain name does not exist */
-#define DNS_ERR_NOTEXIST 3
-/** The name server does not support the requested kind of query */
-#define DNS_ERR_NOTIMPL 4
-/** The name server refuses to reform the specified operation for policy
- * reasons */
-#define DNS_ERR_REFUSED 5
-/** The reply was truncated or ill-formated */
-#define DNS_ERR_TRUNCATED 65
-/** An unknown error occurred */
-#define DNS_ERR_UNKNOWN 66
-/** Communication with the server timed out */
-#define DNS_ERR_TIMEOUT 67
-/** The request was canceled because the DNS subsystem was shut down. */
-#define DNS_ERR_SHUTDOWN 68
-
-#define DNS_IPv4_A 1
-#define DNS_PTR 2
-#define DNS_IPv6_AAAA 3
-
-#define DNS_QUERY_NO_SEARCH 1
-
-#define DNS_OPTION_SEARCH 1
-#define DNS_OPTION_NAMESERVERS 2
-#define DNS_OPTION_MISC 4
-#define DNS_OPTIONS_ALL 7
-
-/**
- * The callback that contains the results from a lookup.
- * - type is either DNS_IPv4_A or DNS_PTR or DNS_IPv6_AAAA
- * - count contains the number of addresses of form type
- * - ttl is the number of seconds the resolution may be cached for.
- * - addresses needs to be cast according to type
- */
-typedef void (*evdns_callback_type) (int result, char type, int count, int ttl, void *addresses, void *arg);
-
-struct evdns_base;
-struct event_base;
-
-/**
- Initialize the asynchronous DNS library.
-
- This function initializes support for non-blocking name resolution by
- calling evdns_resolv_conf_parse() on UNIX and
- evdns_config_windows_nameservers() on Windows.
-
- @return 0 if successful, or -1 if an error occurred
- @see evdns_shutdown()
- */
-int evdns_init(void);
-struct evdns_base * evdns_base_new(struct event_base *event_base, int initialize_nameservers);
-
-
-/**
- Shut down the asynchronous DNS resolver and terminate all active requests.
-
- If the 'fail_requests' option is enabled, all active requests will return
- an empty result with the error flag set to DNS_ERR_SHUTDOWN. Otherwise,
- the requests will be silently discarded.
-
- @param fail_requests if zero, active requests will be aborted; if non-zero,
- active requests will return DNS_ERR_SHUTDOWN.
- @see evdns_init()
- */
-void evdns_shutdown(int fail_requests);
-void evdns_base_free(struct evdns_base *base, int fail_requests);
-
-
-/**
- Convert a DNS error code to a string.
-
- @param err the DNS error code
- @return a string containing an explanation of the error code
-*/
-const char *evdns_err_to_string(int err);
-
-
-/**
- Add a nameserver.
-
- The address should be an IPv4 address in network byte order.
- The type of address is chosen so that it matches in_addr.s_addr.
-
- @param address an IP address in network byte order
- @return 0 if successful, or -1 if an error occurred
- @see evdns_nameserver_ip_add()
- */
-int evdns_nameserver_add(unsigned long int address);
-int evdns_base_nameserver_add(struct evdns_base *base,
- unsigned long int address);
-
-/**
- Get the number of configured nameservers.
-
- This returns the number of configured nameservers (not necessarily the
- number of running nameservers). This is useful for double-checking
- whether our calls to the various nameserver configuration functions
- have been successful.
-
- @return the number of configured nameservers
- @see evdns_nameserver_add()
- */
-int evdns_count_nameservers(void);
-
-int evdns_base_count_nameservers(struct evdns_base *base);
-
-
-/**
- Remove all configured nameservers, and suspend all pending resolves.
-
- Resolves will not necessarily be re-attempted until evdns_resume() is called.
-
- @return 0 if successful, or -1 if an error occurred
- @see evdns_resume()
- */
-int evdns_clear_nameservers_and_suspend(void);
-int evdns_base_clear_nameservers_and_suspend(struct evdns_base *base);
-
-
-/**
- Resume normal operation and continue any suspended resolve requests.
-
- Re-attempt resolves left in limbo after an earlier call to
- evdns_clear_nameservers_and_suspend().
-
- @return 0 if successful, or -1 if an error occurred
- @see evdns_clear_nameservers_and_suspend()
- */
-int evdns_resume(void);
-int evdns_base_resume(struct evdns_base *base);
-
-/**
- Add a nameserver.
-
- This wraps the evdns_nameserver_add() function by parsing a string as an IP
- address and adds it as a nameserver.
-
- @return 0 if successful, or -1 if an error occurred
- @see evdns_nameserver_add()
- */
-int evdns_nameserver_ip_add(const char *ip_as_string);
-int evdns_base_nameserver_ip_add(struct evdns_base *base,
- const char *ip_as_string);
-
-struct evdns_request;
-
-/**
- Lookup an A record for a given name.
-
- @param name a DNS hostname
- @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
- @param callback a callback function to invoke when the request is completed
- @param ptr an argument to pass to the callback function
- @return 0 if successful, or -1 if an error occurred
- @see evdns_resolve_ipv6(), evdns_resolve_reverse(), evdns_resolve_reverse_ipv6()
- */
-int evdns_resolve_ipv4(const char *name, int flags, evdns_callback_type callback, void *ptr);
-struct evdns_request *evdns_base_resolve_ipv4(struct evdns_base *base, const char *name, int flags, evdns_callback_type callback, void *ptr);
-
-/**
- Lookup an AAAA record for a given name.
-
- @param name a DNS hostname
- @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
- @param callback a callback function to invoke when the request is completed
- @param ptr an argument to pass to the callback function
- @return 0 if successful, or -1 if an error occurred
- @see evdns_resolve_ipv4(), evdns_resolve_reverse(), evdns_resolve_reverse_ipv6()
- */
-int evdns_resolve_ipv6(const char *name, int flags, evdns_callback_type callback, void *ptr);
-struct evdns_request *evdns_base_resolve_ipv6(struct evdns_base *base, const char *name, int flags, evdns_callback_type callback, void *ptr);
-
-struct in_addr;
-struct in6_addr;
-
-/**
- Lookup a PTR record for a given IP address.
-
- @param in an IPv4 address
- @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
- @param callback a callback function to invoke when the request is completed
- @param ptr an argument to pass to the callback function
- @return 0 if successful, or -1 if an error occurred
- @see evdns_resolve_reverse_ipv6()
- */
-int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
-struct evdns_request *evdns_base_resolve_reverse(struct evdns_base *base, struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
-
-
-/**
- Lookup a PTR record for a given IPv6 address.
-
- @param in an IPv6 address
- @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
- @param callback a callback function to invoke when the request is completed
- @param ptr an argument to pass to the callback function
- @return 0 if successful, or -1 if an error occurred
- @see evdns_resolve_reverse_ipv6()
- */
-int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
-struct evdns_request *evdns_base_resolve_reverse_ipv6(struct evdns_base *base, struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
-
-
-/**
- Set the value of a configuration option.
-
- The currently available configuration options are:
-
- ndots, timeout, max-timeouts, max-inflight, and attempts
-
- @param option the name of the configuration option to be modified
- @param val the value to be set
- @param flags either 0 | DNS_OPTION_SEARCH | DNS_OPTION_MISC
- @return 0 if successful, or -1 if an error occurred
- */
-int evdns_set_option(const char *option, const char *val, int flags);
-int evdns_base_set_option(struct evdns_base *base, const char *option, const char *val, int flags);
-
-
-/**
- Parse a resolv.conf file.
-
- The 'flags' parameter determines what information is parsed from the
- resolv.conf file. See the man page for resolv.conf for the format of this
- file.
-
- The following directives are not parsed from the file: sortlist, rotate,
- no-check-names, inet6, debug.
-
- If this function encounters an error, the possible return values are: 1 =
- failed to open file, 2 = failed to stat file, 3 = file too large, 4 = out of
- memory, 5 = short read from file, 6 = no nameservers listed in the file
-
- @param flags any of DNS_OPTION_NAMESERVERS|DNS_OPTION_SEARCH|DNS_OPTION_MISC|
- DNS_OPTIONS_ALL
- @param filename the path to the resolv.conf file
- @return 0 if successful, or various positive error codes if an error
- occurred (see above)
- @see resolv.conf(3), evdns_config_windows_nameservers()
- */
-int evdns_resolv_conf_parse(int flags, const char *const filename);
-int evdns_base_resolv_conf_parse(struct evdns_base *base, int flags, const char *const filename);
-
-
-/**
- Obtain nameserver information using the Windows API.
-
- Attempt to configure a set of nameservers based on platform settings on
- a win32 host. Preferentially tries to use GetNetworkParams; if that fails,
- looks in the registry.
-
- @return 0 if successful, or -1 if an error occurred
- @see evdns_resolv_conf_parse()
- */
-#ifdef MS_WINDOWS
-int evdns_config_windows_nameservers(void);
-#endif
-
-
-/**
- Clear the list of search domains.
- */
-void evdns_search_clear(void);
-void evdns_base_search_clear(struct evdns_base *base);
-
-
-/**
- Add a domain to the list of search domains
-
- @param domain the domain to be added to the search list
- */
-void evdns_search_add(const char *domain);
-void evdns_base_search_add(struct evdns_base *base, const char *domain);
-
-
-/**
- Set the 'ndots' parameter for searches.
-
- Sets the number of dots which, when found in a name, causes
- the first query to be without any search domain.
-
- @param ndots the new ndots parameter
- */
-void evdns_search_ndots_set(const int ndots);
-void evdns_base_search_ndots_set(struct evdns_base *base, const int ndots);
-
-/**
- A callback that is invoked when a log message is generated
-
- @param is_warning indicates if the log message is a 'warning'
- @param msg the content of the log message
- */
-typedef void (*evdns_debug_log_fn_type)(int is_warning, const char *msg);
-
-
-/**
- Set the callback function to handle log messages.
-
- @param fn the callback to be invoked when a log message is generated
- */
-void evdns_set_log_fn(evdns_debug_log_fn_type fn);
-
-/**
- Set a callback that will be invoked to generate transaction IDs. By
- default, we pick transaction IDs based on the current clock time.
-
- @param fn the new callback, or NULL to use the default.
- */
-void evdns_set_transaction_id_fn(ev_uint16_t (*fn)(void));
-
-#define DNS_NO_SEARCH 1
-
-/*
- * Structures and functions used to implement a DNS server.
- */
-
-struct evdns_server_request {
- int flags;
- int nquestions;
- struct evdns_server_question **questions;
-};
-struct evdns_server_question {
- int type;
-#ifdef __cplusplus
- int dns_question_class;
-#else
- /* You should refer to this field as "dns_question_class". The
- * name "class" works in C for backward compatibility, and will be
- * removed in a future version. (1.5 or later). */
- int class;
-#define dns_question_class class
-#endif
- char name[1];
-};
-typedef void (*evdns_request_callback_fn_type)(struct evdns_server_request *, void *);
-#define EVDNS_ANSWER_SECTION 0
-#define EVDNS_AUTHORITY_SECTION 1
-#define EVDNS_ADDITIONAL_SECTION 2
-
-#define EVDNS_TYPE_A 1
-#define EVDNS_TYPE_NS 2
-#define EVDNS_TYPE_CNAME 5
-#define EVDNS_TYPE_SOA 6
-#define EVDNS_TYPE_PTR 12
-#define EVDNS_TYPE_MX 15
-#define EVDNS_TYPE_TXT 16
-#define EVDNS_TYPE_AAAA 28
-
-#define EVDNS_QTYPE_AXFR 252
-#define EVDNS_QTYPE_ALL 255
-
-#define EVDNS_CLASS_INET 1
-
-/* flags that can be set in answers; as part of the err parameter */
-#define EVDNS_FLAGS_AA 0x400
-#define EVDNS_FLAGS_RD 0x080
-
-struct evdns_server_port *evdns_add_server_port(int socket, int is_tcp, evdns_request_callback_fn_type callback, void *user_data);
-struct evdns_server_port *evdns_add_server_port_with_base(struct event_base *base, int socket, int is_tcp, evdns_request_callback_fn_type callback, void *user_data);
-void evdns_close_server_port(struct evdns_server_port *port);
-
-/** allows setting of the AA or RD flags */
-void evdns_server_request_set_flags(struct evdns_server_request *req, int flags);
-
-int evdns_server_request_add_reply(struct evdns_server_request *req, int section, const char *name, int type, int dns_class, int ttl, int datalen, int is_name, const char *data);
-int evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl);
-int evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl);
-int evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl);
-int evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl);
-
-int evdns_server_request_respond(struct evdns_server_request *req, int err);
-int evdns_server_request_drop(struct evdns_server_request *req);
-struct sockaddr;
-int evdns_server_request_get_requesting_addr(struct evdns_server_request *_req, struct sockaddr *sa, int addr_len);
-
-#ifdef __cplusplus
-}
-#endif
+#include <event.h>
+#include <event2/dns.h>
+#include <event2/dns_compat.h>
+#include <event2/dns_struct.h>
-#endif /* !EVENTDNS_H */
+#endif /* _EVDNS_H_ */
--- /dev/null
+/*
+ * Copyright (c) 2006 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+
+/*
+ * The original DNS code is due to Adam Langley with heavy
+ * modifications by Nick Mathewson. Adam put his DNS software in the
+ * public domain. You can find his original copyright below. Please,
+ * aware that the code as part of libevent is governed by the 3-clause
+ * BSD license above.
+ *
+ * This software is Public Domain. To view a copy of the public domain dedication,
+ * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
+ * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
+ *
+ * I ask and expect, but do not require, that all derivative works contain an
+ * attribution similar to:
+ * Parts developed by Adam Langley <agl@imperialviolet.org>
+ *
+ * You may wish to replace the word "Parts" with something else depending on
+ * the amount of original code.
+ *
+ * (Derivative works does not include programs which link against, run or include
+ * the source verbatim in their source distributions)
+ */
+
+/** @file dns.h
+ *
+ * Welcome, gentle reader
+ *
+ * Async DNS lookups are really a whole lot harder than they should be,
+ * mostly stemming from the fact that the libc resolver has never been
+ * very good at them. Before you use this library you should see if libc
+ * can do the job for you with the modern async call getaddrinfo_a
+ * (see http://www.imperialviolet.org/page25.html#e498). Otherwise,
+ * please continue.
+ *
+ * This code is based on libevent and you must call event_init before
+ * any of the APIs in this file. You must also seed the OpenSSL random
+ * source if you are using OpenSSL for ids (see below).
+ *
+ * This library is designed to be included and shipped with your source
+ * code. You statically link with it. You should also test for the
+ * existence of strtok_r and define HAVE_STRTOK_R if you have it.
+ *
+ * The DNS protocol requires a good source of id numbers and these
+ * numbers should be unpredictable for spoofing reasons. There are
+ * three methods for generating them here and you must define exactly
+ * one of them. In increasing order of preference:
+ *
+ * DNS_USE_GETTIMEOFDAY_FOR_ID:
+ * Using the bottom 16 bits of the usec result from gettimeofday. This
+ * is a pretty poor solution but should work anywhere.
+ * DNS_USE_CPU_CLOCK_FOR_ID:
+ * Using the bottom 16 bits of the nsec result from the CPU's time
+ * counter. This is better, but may not work everywhere. Requires
+ * POSIX realtime support and you'll need to link against -lrt on
+ * glibc systems at least.
+ * DNS_USE_OPENSSL_FOR_ID:
+ * Uses the OpenSSL RAND_bytes call to generate the data. You must
+ * have seeded the pool before making any calls to this library.
+ *
+ * The library keeps track of the state of nameservers and will avoid
+ * them when they go down. Otherwise it will round robin between them.
+ *
+ * Quick start guide:
+ * #include "evdns.h"
+ * void callback(int result, char type, int count, int ttl,
+ * void *addresses, void *arg);
+ * evdns_resolv_conf_parse(DNS_OPTIONS_ALL, "/etc/resolv.conf");
+ * evdns_resolve("www.hostname.com", 0, callback, NULL);
+ *
+ * When the lookup is complete the callback function is called. The
+ * first argument will be one of the DNS_ERR_* defines in evdns.h.
+ * Hopefully it will be DNS_ERR_NONE, in which case type will be
+ * DNS_IPv4_A, count will be the number of IP addresses, ttl is the time
+ * which the data can be cached for (in seconds), addresses will point
+ * to an array of uint32_t's and arg will be whatever you passed to
+ * evdns_resolve.
+ *
+ * Searching:
+ *
+ * In order for this library to be a good replacement for glibc's resolver it
+ * supports searching. This involves setting a list of default domains, in
+ * which names will be queried for. The number of dots in the query name
+ * determines the order in which this list is used.
+ *
+ * Searching appears to be a single lookup from the point of view of the API,
+ * although many DNS queries may be generated from a single call to
+ * evdns_resolve. Searching can also drastically slow down the resolution
+ * of names.
+ *
+ * To disable searching:
+ * 1. Never set it up. If you never call evdns_resolv_conf_parse or
+ * evdns_search_add then no searching will occur.
+ *
+ * 2. If you do call evdns_resolv_conf_parse then don't pass
+ * DNS_OPTION_SEARCH (or DNS_OPTIONS_ALL, which implies it).
+ *
+ * 3. When calling evdns_resolve, pass the DNS_QUERY_NO_SEARCH flag.
+ *
+ * The order of searches depends on the number of dots in the name. If the
+ * number is greater than the ndots setting then the names is first tried
+ * globally. Otherwise each search domain is appended in turn.
+ *
+ * The ndots setting can either be set from a resolv.conf, or by calling
+ * evdns_search_ndots_set.
+ *
+ * For example, with ndots set to 1 (the default) and a search domain list of
+ * ["myhome.net"]:
+ * Query: www
+ * Order: www.myhome.net, www.
+ *
+ * Query: www.abc
+ * Order: www.abc., www.abc.myhome.net
+ *
+ * Internals:
+ *
+ * Requests are kept in two queues. The first is the inflight queue. In
+ * this queue requests have an allocated transaction id and nameserver.
+ * They will soon be transmitted if they haven't already been.
+ *
+ * The second is the waiting queue. The size of the inflight ring is
+ * limited and all other requests wait in waiting queue for space. This
+ * bounds the number of concurrent requests so that we don't flood the
+ * nameserver. Several algorithms require a full walk of the inflight
+ * queue and so bounding its size keeps thing going nicely under huge
+ * (many thousands of requests) loads.
+ *
+ * If a nameserver loses too many requests it is considered down and we
+ * try not to use it. After a while we send a probe to that nameserver
+ * (a lookup for google.com) and, if it replies, we consider it working
+ * again. If the nameserver fails a probe we wait longer to try again
+ * with the next probe.
+ */
+
+#ifndef _EVENT2_DNS_H_
+#define _EVENT2_DNS_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* For integer types. */
+#include <event2/util.h>
+
+/** Error codes 0-5 are as described in RFC 1035. */
+#define DNS_ERR_NONE 0
+/** The name server was unable to interpret the query */
+#define DNS_ERR_FORMAT 1
+/** The name server was unable to process this query due to a problem with the
+ * name server */
+#define DNS_ERR_SERVERFAILED 2
+/** The domain name does not exist */
+#define DNS_ERR_NOTEXIST 3
+/** The name server does not support the requested kind of query */
+#define DNS_ERR_NOTIMPL 4
+/** The name server refuses to reform the specified operation for policy
+ * reasons */
+#define DNS_ERR_REFUSED 5
+/** The reply was truncated or ill-formated */
+#define DNS_ERR_TRUNCATED 65
+/** An unknown error occurred */
+#define DNS_ERR_UNKNOWN 66
+/** Communication with the server timed out */
+#define DNS_ERR_TIMEOUT 67
+/** The request was canceled because the DNS subsystem was shut down. */
+#define DNS_ERR_SHUTDOWN 68
+
+#define DNS_IPv4_A 1
+#define DNS_PTR 2
+#define DNS_IPv6_AAAA 3
+
+#define DNS_QUERY_NO_SEARCH 1
+
+#define DNS_OPTION_SEARCH 1
+#define DNS_OPTION_NAMESERVERS 2
+#define DNS_OPTION_MISC 4
+#define DNS_OPTIONS_ALL 7
+
+/**
+ * The callback that contains the results from a lookup.
+ * - type is either DNS_IPv4_A or DNS_PTR or DNS_IPv6_AAAA
+ * - count contains the number of addresses of form type
+ * - ttl is the number of seconds the resolution may be cached for.
+ * - addresses needs to be cast according to type
+ */
+typedef void (*evdns_callback_type) (int result, char type, int count, int ttl, void *addresses, void *arg);
+
+struct evdns_base;
+struct event_base;
+
+/**
+ Initialize the asynchronous DNS library.
+
+ This function initializes support for non-blocking name resolution by
+ calling evdns_resolv_conf_parse() on UNIX and
+ evdns_config_windows_nameservers() on Windows.
+
+ @param event_base the event base to associate the dns client with
+ @param initialize_nameservers 1 if resolve.conf processing should occur
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_base_free()
+ */
+struct evdns_base * evdns_base_new(struct event_base *event_base, int initialize_nameservers);
+
+
+/**
+ Shut down the asynchronous DNS resolver and terminate all active requests.
+
+ If the 'fail_requests' option is enabled, all active requests will return
+ an empty result with the error flag set to DNS_ERR_SHUTDOWN. Otherwise,
+ the requests will be silently discarded.
+
+ @param evdns_base the evdns base to free
+ @param fail_requests if zero, active requests will be aborted; if non-zero,
+ active requests will return DNS_ERR_SHUTDOWN.
+ @see evdns_base_new()
+ */
+void evdns_base_free(struct evdns_base *base, int fail_requests);
+
+/**
+ Convert a DNS error code to a string.
+
+ @param err the DNS error code
+ @return a string containing an explanation of the error code
+*/
+const char *evdns_err_to_string(int err);
+
+
+/**
+ Add a nameserver.
+
+ The address should be an IPv4 address in network byte order.
+ The type of address is chosen so that it matches in_addr.s_addr.
+
+ @param base the evdns_base to which to add the name server
+ @param address an IP address in network byte order
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_base_nameserver_ip_add()
+ */
+int evdns_base_nameserver_add(struct evdns_base *base,
+ unsigned long int address);
+
+/**
+ Get the number of configured nameservers.
+
+ This returns the number of configured nameservers (not necessarily the
+ number of running nameservers). This is useful for double-checking
+ whether our calls to the various nameserver configuration functions
+ have been successful.
+
+ @param base the evdns_base to which to apply this operation
+ @return the number of configured nameservers
+ @see evdns_base_nameserver_add()
+ */
+int evdns_base_count_nameservers(struct evdns_base *base);
+
+/**
+ Remove all configured nameservers, and suspend all pending resolves.
+
+ Resolves will not necessarily be re-attempted until evdns_resume() is called.
+
+ @param base the evdns_base to which to apply this operation
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_base_resume()
+ */
+int evdns_base_clear_nameservers_and_suspend(struct evdns_base *base);
+
+
+/**
+ Resume normal operation and continue any suspended resolve requests.
+
+ Re-attempt resolves left in limbo after an earlier call to
+ evdns_clear_nameservers_and_suspend().
+
+ @param base the evdns_base to which to apply this operation
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_base_clear_nameservers_and_suspend()
+ */
+int evdns_base_resume(struct evdns_base *base);
+
+/**
+ Add a nameserver.
+
+ This wraps the evdns_nameserver_add() function by parsing a string as an IP
+ address and adds it as a nameserver.
+
+ @param base the evdns_base to which to apply this operation
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_base_nameserver_add()
+ */
+int evdns_base_nameserver_ip_add(struct evdns_base *base,
+ const char *ip_as_string);
+
+struct evdns_request;
+
+/**
+ Lookup an A record for a given name.
+
+ @param base the evdns_base to which to apply this operation
+ @param name a DNS hostname
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_ipv6(), evdns_resolve_reverse(), evdns_resolve_reverse_ipv6()
+ */
+struct evdns_request *evdns_base_resolve_ipv4(struct evdns_base *base, const char *name, int flags, evdns_callback_type callback, void *ptr);
+
+/**
+ Lookup an AAAA record for a given name.
+
+ @param base the evdns_base to which to apply this operation
+ @param name a DNS hostname
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_ipv4(), evdns_resolve_reverse(), evdns_resolve_reverse_ipv6()
+ */
+struct evdns_request *evdns_base_resolve_ipv6(struct evdns_base *base, const char *name, int flags, evdns_callback_type callback, void *ptr);
+
+struct in_addr;
+struct in6_addr;
+
+/**
+ Lookup a PTR record for a given IP address.
+
+ @param base the evdns_base to which to apply this operation
+ @param in an IPv4 address
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_reverse_ipv6()
+ */
+struct evdns_request *evdns_base_resolve_reverse(struct evdns_base *base, struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
+
+
+/**
+ Lookup a PTR record for a given IPv6 address.
+
+ @param base the evdns_base to which to apply this operation
+ @param in an IPv6 address
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_reverse_ipv6()
+ */
+struct evdns_request *evdns_base_resolve_reverse_ipv6(struct evdns_base *base, struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
+
+
+/**
+ Set the value of a configuration option.
+
+ The currently available configuration options are:
+
+ ndots, timeout, max-timeouts, max-inflight, and attempts
+
+ @param base the evdns_base to which to apply this operation
+ @param option the name of the configuration option to be modified
+ @param val the value to be set
+ @param flags either 0 | DNS_OPTION_SEARCH | DNS_OPTION_MISC
+ @return 0 if successful, or -1 if an error occurred
+ */
+int evdns_base_set_option(struct evdns_base *base, const char *option, const char *val, int flags);
+
+
+/**
+ Parse a resolv.conf file.
+
+ The 'flags' parameter determines what information is parsed from the
+ resolv.conf file. See the man page for resolv.conf for the format of this
+ file.
+
+ The following directives are not parsed from the file: sortlist, rotate,
+ no-check-names, inet6, debug.
+
+ If this function encounters an error, the possible return values are: 1 =
+ failed to open file, 2 = failed to stat file, 3 = file too large, 4 = out of
+ memory, 5 = short read from file, 6 = no nameservers listed in the file
+
+ @param base the evdns_base to which to apply this operation
+ @param flags any of DNS_OPTION_NAMESERVERS|DNS_OPTION_SEARCH|DNS_OPTION_MISC|
+ DNS_OPTIONS_ALL
+ @param filename the path to the resolv.conf file
+ @return 0 if successful, or various positive error codes if an error
+ occurred (see above)
+ @see resolv.conf(3), evdns_config_windows_nameservers()
+ */
+int evdns_base_resolv_conf_parse(struct evdns_base *base, int flags, const char *const filename);
+
+
+/**
+ Obtain nameserver information using the Windows API.
+
+ Attempt to configure a set of nameservers based on platform settings on
+ a win32 host. Preferentially tries to use GetNetworkParams; if that fails,
+ looks in the registry.
+
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolv_conf_parse()
+ */
+#ifdef MS_WINDOWS
+int evdns_config_windows_nameservers(void);
+#endif
+
+
+/**
+ Clear the list of search domains.
+ */
+void evdns_base_search_clear(struct evdns_base *base);
+
+
+/**
+ Add a domain to the list of search domains
+
+ @param domain the domain to be added to the search list
+ */
+void evdns_base_search_add(struct evdns_base *base, const char *domain);
+
+
+/**
+ Set the 'ndots' parameter for searches.
+
+ Sets the number of dots which, when found in a name, causes
+ the first query to be without any search domain.
+
+ @param ndots the new ndots parameter
+ */
+void evdns_base_search_ndots_set(struct evdns_base *base, const int ndots);
+
+/**
+ A callback that is invoked when a log message is generated
+
+ @param is_warning indicates if the log message is a 'warning'
+ @param msg the content of the log message
+ */
+typedef void (*evdns_debug_log_fn_type)(int is_warning, const char *msg);
+
+
+/**
+ Set the callback function to handle log messages.
+
+ @param fn the callback to be invoked when a log message is generated
+ */
+void evdns_set_log_fn(evdns_debug_log_fn_type fn);
+
+/**
+ Set a callback that will be invoked to generate transaction IDs. By
+ default, we pick transaction IDs based on the current clock time.
+
+ @param fn the new callback, or NULL to use the default.
+ */
+void evdns_set_transaction_id_fn(ev_uint16_t (*fn)(void));
+
+#define DNS_NO_SEARCH 1
+
+/*
+ * Functions used to implement a DNS server.
+ */
+
+struct evdns_server_request;
+struct evdns_server_question;
+
+typedef void (*evdns_request_callback_fn_type)(struct evdns_server_request *, void *);
+#define EVDNS_ANSWER_SECTION 0
+#define EVDNS_AUTHORITY_SECTION 1
+#define EVDNS_ADDITIONAL_SECTION 2
+
+#define EVDNS_TYPE_A 1
+#define EVDNS_TYPE_NS 2
+#define EVDNS_TYPE_CNAME 5
+#define EVDNS_TYPE_SOA 6
+#define EVDNS_TYPE_PTR 12
+#define EVDNS_TYPE_MX 15
+#define EVDNS_TYPE_TXT 16
+#define EVDNS_TYPE_AAAA 28
+
+#define EVDNS_QTYPE_AXFR 252
+#define EVDNS_QTYPE_ALL 255
+
+#define EVDNS_CLASS_INET 1
+
+/* flags that can be set in answers; as part of the err parameter */
+#define EVDNS_FLAGS_AA 0x400
+#define EVDNS_FLAGS_RD 0x080
+
+struct evdns_server_port *evdns_add_server_port(int socket, int is_tcp, evdns_request_callback_fn_type callback, void *user_data);
+struct evdns_server_port *evdns_add_server_port_with_base(struct event_base *base, int socket, int is_tcp, evdns_request_callback_fn_type callback, void *user_data);
+void evdns_close_server_port(struct evdns_server_port *port);
+
+/** allows setting of the AA or RD flags */
+void evdns_server_request_set_flags(struct evdns_server_request *req, int flags);
+
+int evdns_server_request_add_reply(struct evdns_server_request *req, int section, const char *name, int type, int dns_class, int ttl, int datalen, int is_name, const char *data);
+int evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl);
+int evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, void *addrs, int ttl);
+int evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl);
+int evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl);
+
+int evdns_server_request_respond(struct evdns_server_request *req, int err);
+int evdns_server_request_drop(struct evdns_server_request *req);
+struct sockaddr;
+int evdns_server_request_get_requesting_addr(struct evdns_server_request *_req, struct sockaddr *sa, int addr_len);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* !_EVENT2_DNS_H_ */
--- /dev/null
+/*
+ * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+#ifndef _EVENT2_DNS_COMPAT_H_
+#define _EVENT2_DNS_COMPAT_H_
+
+/** @file dns_compat.h
+
+ Potentially non-threadsafe versions of the functions in dns.h: provided
+ only for backwards compatibility.
+
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <event-config.h>
+#ifdef _EVENT_HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef _EVENT_HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+/* For int types. */
+#include <event2/util.h>
+
+/**
+ Initialize the asynchronous DNS library.
+
+ This function initializes support for non-blocking name resolution by
+ calling evdns_resolv_conf_parse() on UNIX and
+ evdns_config_windows_nameservers() on Windows.
+
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_shutdown()
+ */
+int evdns_init(void);
+
+/**
+ Shut down the asynchronous DNS resolver and terminate all active requests.
+
+ If the 'fail_requests' option is enabled, all active requests will return
+ an empty result with the error flag set to DNS_ERR_SHUTDOWN. Otherwise,
+ the requests will be silently discarded.
+
+ @param fail_requests if zero, active requests will be aborted; if non-zero,
+ active requests will return DNS_ERR_SHUTDOWN.
+ @see evdns_init()
+ */
+void evdns_shutdown(int fail_requests);
+
+/**
+ Add a nameserver.
+
+ The address should be an IPv4 address in network byte order.
+ The type of address is chosen so that it matches in_addr.s_addr.
+
+ @param address an IP address in network byte order
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_nameserver_ip_add()
+ */
+int evdns_nameserver_add(unsigned long int address);
+
+/**
+ Get the number of configured nameservers.
+
+ This returns the number of configured nameservers (not necessarily the
+ number of running nameservers). This is useful for double-checking
+ whether our calls to the various nameserver configuration functions
+ have been successful.
+
+ @return the number of configured nameservers
+ @see evdns_nameserver_add()
+ */
+int evdns_count_nameservers(void);
+
+/**
+ Remove all configured nameservers, and suspend all pending resolves.
+
+ Resolves will not necessarily be re-attempted until evdns_resume() is called.
+
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resume()
+ */
+int evdns_clear_nameservers_and_suspend(void);
+
+/**
+ Resume normal operation and continue any suspended resolve requests.
+
+ Re-attempt resolves left in limbo after an earlier call to
+ evdns_clear_nameservers_and_suspend().
+
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_clear_nameservers_and_suspend()
+ */
+int evdns_resume(void);
+
+/**
+ Add a nameserver.
+
+ This wraps the evdns_nameserver_add() function by parsing a string as an IP
+ address and adds it as a nameserver.
+
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_nameserver_add()
+ */
+int evdns_nameserver_ip_add(const char *ip_as_string);
+
+/**
+ Lookup an A record for a given name.
+
+ @param name a DNS hostname
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_ipv6(), evdns_resolve_reverse(), evdns_resolve_reverse_ipv6()
+ */
+int evdns_resolve_ipv4(const char *name, int flags, evdns_callback_type callback, void *ptr);
+
+/**
+ Lookup an AAAA record for a given name.
+
+ @param name a DNS hostname
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_ipv4(), evdns_resolve_reverse(), evdns_resolve_reverse_ipv6()
+ */
+int evdns_resolve_ipv6(const char *name, int flags, evdns_callback_type callback, void *ptr);
+
+struct in_addr;
+struct in6_addr;
+
+/**
+ Lookup a PTR record for a given IP address.
+
+ @param in an IPv4 address
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_reverse_ipv6()
+ */
+int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr);
+
+/**
+ Lookup a PTR record for a given IPv6 address.
+
+ @param in an IPv6 address
+ @param flags either 0, or DNS_QUERY_NO_SEARCH to disable searching for this query.
+ @param callback a callback function to invoke when the request is completed
+ @param ptr an argument to pass to the callback function
+ @return 0 if successful, or -1 if an error occurred
+ @see evdns_resolve_reverse_ipv6()
+ */
+int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr);
+
+/**
+ Set the value of a configuration option.
+
+ The currently available configuration options are:
+
+ ndots, timeout, max-timeouts, max-inflight, and attempts
+
+ @param option the name of the configuration option to be modified
+ @param val the value to be set
+ @param flags either 0 | DNS_OPTION_SEARCH | DNS_OPTION_MISC
+ @return 0 if successful, or -1 if an error occurred
+ */
+int evdns_set_option(const char *option, const char *val, int flags);
+
+/**
+ Parse a resolv.conf file.
+
+ The 'flags' parameter determines what information is parsed from the
+ resolv.conf file. See the man page for resolv.conf for the format of this
+ file.
+
+ The following directives are not parsed from the file: sortlist, rotate,
+ no-check-names, inet6, debug.
+
+ If this function encounters an error, the possible return values are: 1 =
+ failed to open file, 2 = failed to stat file, 3 = file too large, 4 = out of
+ memory, 5 = short read from file, 6 = no nameservers listed in the file
+
+ @param flags any of DNS_OPTION_NAMESERVERS|DNS_OPTION_SEARCH|DNS_OPTION_MISC|
+ DNS_OPTIONS_ALL
+ @param filename the path to the resolv.conf file
+ @return 0 if successful, or various positive error codes if an error
+ occurred (see above)
+ @see resolv.conf(3), evdns_config_windows_nameservers()
+ */
+int evdns_resolv_conf_parse(int flags, const char *const filename);
+
+/**
+ Clear the list of search domains.
+ */
+void evdns_search_clear(void);
+
+/**
+ Add a domain to the list of search domains
+
+ @param domain the domain to be added to the search list
+ */
+void evdns_search_add(const char *domain);
+
+/**
+ Set the 'ndots' parameter for searches.
+
+ Sets the number of dots which, when found in a name, causes
+ the first query to be without any search domain.
+
+ @param ndots the new ndots parameter
+ */
+void evdns_search_ndots_set(const int ndots);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _EVENT2_EVENT_COMPAT_H_ */
--- /dev/null
+/*
+ * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+#ifndef _EVENT2_DNS_STRUCT_H_
+#define _EVENT2_DNS_STRUCT_H_
+
+/** @file dns_struct.h
+
+ Data structures for dns. Using these structures may hurt forward
+ compatibility with later versions of libevent: be careful!
+
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <event-config.h>
+#ifdef _EVENT_HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef _EVENT_HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+/* For int types. */
+#include <event2/util.h>
+
+/*
+ * Structures used to implement a DNS server.
+ */
+
+struct evdns_server_request {
+ int flags;
+ int nquestions;
+ struct evdns_server_question **questions;
+};
+struct evdns_server_question {
+ int type;
+#ifdef __cplusplus
+ int dns_question_class;
+#else
+ /* You should refer to this field as "dns_question_class". The
+ * name "class" works in C for backward compatibility, and will be
+ * removed in a future version. (1.5 or later). */
+ int class;
+#define dns_question_class class
+#endif
+ char name[1];
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _EVENT2_DNS_STRUCT_H_ */
+
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