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Diffstat (limited to 'evdns.h')
| -rw-r--r-- | evdns.h | 367 |
1 files changed, 0 insertions, 367 deletions
diff --git a/evdns.h b/evdns.h deleted file mode 100644 index af7962e..0000000 --- a/evdns.h +++ /dev/null @@ -1,367 +0,0 @@ -/* - * 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) - */ - -/* - * 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 - * - * API reference: - * - * int evdns_nameserver_add(unsigned long int address) - * Add a nameserver. The address should be an IP address in - * network byte order. The type of address is chosen so that - * it matches in_addr.s_addr. - * Returns non-zero on error. - * - * int evdns_nameserver_ip_add(const char *ip_as_string) - * This wraps the above function by parsing a string as an IP - * address and adds it as a nameserver. - * Returns non-zero on error - * - * int evdns_resolve(const char *name, int flags, - * evdns_callback_type callback, - * void *ptr) - * Resolve a name. The name parameter should be a DNS name. - * The flags parameter should be 0, or DNS_QUERY_NO_SEARCH - * which disables searching for this query. (see defn of - * searching above). - * - * The callback argument is a function which is called when - * this query completes and ptr is an argument which is passed - * to that callback function. - * - * Returns non-zero on error - * - * void evdns_search_clear() - * Clears the list of search domains - * - * void evdns_search_add(const char *domain) - * Add a domain to the list of search domains - * - * void evdns_search_ndots_set(int ndots) - * Set the number of dots which, when found in a name, causes - * the first query to be without any search domain. - * - * int evdns_count_nameservers(void) - * Return 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. - * - * int evdns_clear_nameservers_and_suspend(void) - * Remove all currently configured nameservers, and suspend all pending - * resolves. Resolves will not necessarily be re-attempted until - * evdns_resume() is called. - * - * int evdns_resume(void) - * Re-attempt resolves left in limbo after an earlier call to - * evdns_clear_nameservers_and_suspend(). - * - * int evdns_config_windows_nameservers(void) - * 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. Returns 0 on success, nonzero on failure. - * - * int evdns_resolv_conf_parse(int flags, const char *filename) - * Parse a resolv.conf like file from the given filename. - * - * See the man page for resolv.conf for the format of this file. - * The flags argument determines what information is parsed from - * this file: - * DNS_OPTION_SEARCH - domain, search and ndots options - * DNS_OPTION_NAMESERVERS - nameserver lines - * DNS_OPTION_MISC - timeout and attempts options - * DNS_OPTIONS_ALL - all of the above - * The following directives are not parsed from the file: - * sortlist, rotate, no-check-names, inet6, debug - * - * Returns non-zero on error: - * 0 no errors - * 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 in file - * - * 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 - -/* 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); - -int evdns_init(void); -void evdns_shutdown(int fail_requests); -const char *evdns_err_to_string(int err); -int evdns_nameserver_add(unsigned long int address); -int evdns_count_nameservers(void); -int evdns_clear_nameservers_and_suspend(void); -int evdns_resume(void); -int evdns_nameserver_ip_add(const char *ip_as_string); -int evdns_resolve_ipv4(const char *name, int flags, evdns_callback_type callback, void *ptr); -int evdns_resolve_ipv6(const char *name, int flags, evdns_callback_type callback, void *ptr); -struct in_addr; -struct in6_addr; -int evdns_resolve_reverse(struct in_addr *in, int flags, evdns_callback_type callback, void *ptr); -int evdns_resolve_reverse_ipv6(struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr); -int evdns_set_option(const char *option, const char *val, int flags); -int evdns_resolv_conf_parse(int flags, const char *); -#ifdef MS_WINDOWS -int evdns_config_windows_nameservers(void); -#endif -void evdns_search_clear(void); -void evdns_search_add(const char *domain); -void evdns_search_ndots_set(const int ndots); - -typedef void (*evdns_debug_log_fn_type)(int is_warning, const char *msg); -void evdns_set_log_fn(evdns_debug_log_fn_type fn); - -#define DNS_NO_SEARCH 1 - -#ifdef __cplusplus -} -#endif - -/* - * 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; - int class; - 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 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); - -#endif /* !EVENTDNS_H */ |