move libevent into base

third_party/libevent/evdns.h

-/*
- * 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 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 "evutil.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);
-
-/**
-  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);
-
-
-/**
-  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);
-
-
-/**
-  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(const 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(const 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);
-
-
-/**
-  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 WIN32
-int evdns_config_windows_nameservers(void);
-#endif
-
-
-/**
-  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);
-
-/**
-  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
-
-struct evdns_server_port *evdns_add_server_port(int socket, int is_tcp, evdns_request_callback_fn_type callback, void *user_data);
-void evdns_close_server_port(struct evdns_server_port *port);
-
-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  /* !EVENTDNS_H */