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Diffstat (limited to 'external/unbound/libunbound/unbound.h')
| -rw-r--r-- | external/unbound/libunbound/unbound.h | 572 |
1 files changed, 572 insertions, 0 deletions
diff --git a/external/unbound/libunbound/unbound.h b/external/unbound/libunbound/unbound.h new file mode 100644 index 000000000..86bd3bfb4 --- /dev/null +++ b/external/unbound/libunbound/unbound.h @@ -0,0 +1,572 @@ +/* + * unbound.h - unbound validating resolver public API + * + * Copyright (c) 2007, NLnet Labs. All rights reserved. + * + * This software is open source. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 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. + * + * Neither the name of the NLNET LABS nor the names of its contributors may + * be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 COPYRIGHT + * HOLDER OR CONTRIBUTORS 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. + */ + +/** + * \file + * + * This file contains functions to resolve DNS queries and + * validate the answers. Synchonously and asynchronously. + * + * Several ways to use this interface from an application wishing + * to perform (validated) DNS lookups. + * + * All start with + * ctx = ub_ctx_create(); + * err = ub_ctx_add_ta(ctx, "..."); + * err = ub_ctx_add_ta(ctx, "..."); + * ... some lookups + * ... call ub_ctx_delete(ctx); when you want to stop. + * + * Application not threaded. Blocking. + * int err = ub_resolve(ctx, "www.example.com", ... + * if(err) fprintf(stderr, "lookup error: %s\n", ub_strerror(err)); + * ... use the answer + * + * Application not threaded. Non-blocking ('asynchronous'). + * err = ub_resolve_async(ctx, "www.example.com", ... my_callback); + * ... application resumes processing ... + * ... and when either ub_poll(ctx) is true + * ... or when the file descriptor ub_fd(ctx) is readable, + * ... or whenever, the app calls ... + * ub_process(ctx); + * ... if no result is ready, the app resumes processing above, + * ... or process() calls my_callback() with results. + * + * ... if the application has nothing more to do, wait for answer + * ub_wait(ctx); + * + * Application threaded. Blocking. + * Blocking, same as above. The current thread does the work. + * Multiple threads can use the *same context*, each does work and uses + * shared cache data from the context. + * + * Application threaded. Non-blocking ('asynchronous'). + * ... setup threaded-asynchronous config option + * err = ub_ctx_async(ctx, 1); + * ... same as async for non-threaded + * ... the callbacks are called in the thread that calls process(ctx) + * + * Openssl needs to have locking in place, and the application must set + * it up, because a mere library cannot do this, use the calls + * CRYPTO_set_id_callback and CRYPTO_set_locking_callback. + * + * If no threading is compiled in, the above async example uses fork(2) to + * create a process to perform the work. The forked process exits when the + * calling process exits, or ctx_delete() is called. + * Otherwise, for asynchronous with threading, a worker thread is created. + * + * The blocking calls use shared ctx-cache when threaded. Thus + * ub_resolve() and ub_resolve_async() && ub_wait() are + * not the same. The first makes the current thread do the work, setting + * up buffers, etc, to perform the work (but using shared cache data). + * The second calls another worker thread (or process) to perform the work. + * And no buffers need to be set up, but a context-switch happens. + */ +#ifndef _UB_UNBOUND_H +#define _UB_UNBOUND_H + +#ifdef __cplusplus +extern "C" { +#endif + +/** the version of this header file */ +#define UNBOUND_VERSION_MAJOR @UNBOUND_VERSION_MAJOR@ +#define UNBOUND_VERSION_MINOR @UNBOUND_VERSION_MINOR@ +#define UNBOUND_VERSION_MICRO @UNBOUND_VERSION_MICRO@ + +/** + * The validation context is created to hold the resolver status, + * validation keys and a small cache (containing messages, rrsets, + * roundtrip times, trusted keys, lameness information). + * + * Its contents are internally defined. + */ +struct ub_ctx; + +/** + * The validation and resolution results. + * Allocated by the resolver, and need to be freed by the application + * with ub_resolve_free(). + */ +struct ub_result { + /** The original question, name text string. */ + char* qname; + /** the type asked for */ + int qtype; + /** the class asked for */ + int qclass; + + /** + * a list of network order DNS rdata items, terminated with a + * NULL pointer, so that data[0] is the first result entry, + * data[1] the second, and the last entry is NULL. + * If there was no data, data[0] is NULL. + */ + char** data; + + /** the length in bytes of the data items, len[i] for data[i] */ + int* len; + + /** + * canonical name for the result (the final cname). + * zero terminated string. + * May be NULL if no canonical name exists. + */ + char* canonname; + + /** + * DNS RCODE for the result. May contain additional error code if + * there was no data due to an error. 0 (NOERROR) if okay. + */ + int rcode; + + /** + * The DNS answer packet. Network formatted. Can contain DNSSEC types. + */ + void* answer_packet; + /** length of the answer packet in octets. */ + int answer_len; + + /** + * If there is any data, this is true. + * If false, there was no data (nxdomain may be true, rcode can be set). + */ + int havedata; + + /** + * If there was no data, and the domain did not exist, this is true. + * If it is false, and there was no data, then the domain name + * is purported to exist, but the requested data type is not available. + */ + int nxdomain; + + /** + * True, if the result is validated securely. + * False, if validation failed or domain queried has no security info. + * + * It is possible to get a result with no data (havedata is false), + * and secure is true. This means that the non-existance of the data + * was cryptographically proven (with signatures). + */ + int secure; + + /** + * If the result was not secure (secure==0), and this result is due + * to a security failure, bogus is true. + * This means the data has been actively tampered with, signatures + * failed, expected signatures were not present, timestamps on + * signatures were out of date and so on. + * + * If !secure and !bogus, this can happen if the data is not secure + * because security is disabled for that domain name. + * This means the data is from a domain where data is not signed. + */ + int bogus; + + /** + * If the result is bogus this contains a string (zero terminated) + * that describes the failure. There may be other errors as well + * as the one described, the description may not be perfectly accurate. + * Is NULL if the result is not bogus. + */ + char* why_bogus; + + /** + * TTL for the result, in seconds. If the security is bogus, then + * you also cannot trust this value. + */ + int ttl; +}; + +/** + * Callback for results of async queries. + * The readable function definition looks like: + * void my_callback(void* my_arg, int err, struct ub_result* result); + * It is called with + * void* my_arg: your pointer to a (struct of) data of your choice, + * or NULL. + * int err: if 0 all is OK, otherwise an error occured and no results + * are forthcoming. + * struct result: pointer to more detailed result structure. + * This structure is allocated on the heap and needs to be + * freed with ub_resolve_free(result); + */ +typedef void (*ub_callback_t)(void*, int, struct ub_result*); + +/** + * Create a resolving and validation context. + * The information from /etc/resolv.conf and /etc/hosts is not utilised by + * default. Use ub_ctx_resolvconf and ub_ctx_hosts to read them. + * @return a new context. default initialisation. + * returns NULL on error. + */ +struct ub_ctx* ub_ctx_create(void); + +/** + * Destroy a validation context and free all its resources. + * Outstanding async queries are killed and callbacks are not called for them. + * @param ctx: context to delete. + */ +void ub_ctx_delete(struct ub_ctx* ctx); + +/** + * Set an option for the context. + * @param ctx: context. + * @param opt: option name from the unbound.conf config file format. + * (not all settings applicable). The name includes the trailing ':' + * for example ub_ctx_set_option(ctx, "logfile:", "mylog.txt"); + * This is a power-users interface that lets you specify all sorts + * of options. + * For some specific options, such as adding trust anchors, special + * routines exist. + * @param val: value of the option. + * @return: 0 if OK, else error. + */ +int ub_ctx_set_option(struct ub_ctx* ctx, const char* opt, const char* val); + +/** + * Get an option from the context. + * @param ctx: context. + * @param opt: option name from the unbound.conf config file format. + * (not all settings applicable). The name excludes the trailing ':' + * for example ub_ctx_get_option(ctx, "logfile", &result); + * This is a power-users interface that lets you specify all sorts + * of options. + * @param str: the string is malloced and returned here. NULL on error. + * The caller must free() the string. In cases with multiple + * entries (auto-trust-anchor-file), a newline delimited list is + * returned in the string. + * @return 0 if OK else an error code (malloc failure, syntax error). + */ +int ub_ctx_get_option(struct ub_ctx* ctx, const char* opt, char** str); + +/** + * setup configuration for the given context. + * @param ctx: context. + * @param fname: unbound config file (not all settings applicable). + * This is a power-users interface that lets you specify all sorts + * of options. + * For some specific options, such as adding trust anchors, special + * routines exist. + * @return: 0 if OK, else error. + */ +int ub_ctx_config(struct ub_ctx* ctx, const char* fname); + +/** + * Set machine to forward DNS queries to, the caching resolver to use. + * IP4 or IP6 address. Forwards all DNS requests to that machine, which + * is expected to run a recursive resolver. If the proxy is not + * DNSSEC-capable, validation may fail. Can be called several times, in + * that case the addresses are used as backup servers. + * + * To read the list of nameservers from /etc/resolv.conf (from DHCP or so), + * use the call ub_ctx_resolvconf. + * + * @param ctx: context. + * At this time it is only possible to set configuration before the + * first resolve is done. + * @param addr: address, IP4 or IP6 in string format. + * If the addr is NULL, forwarding is disabled. + * @return 0 if OK, else error. + */ +int ub_ctx_set_fwd(struct ub_ctx* ctx, const char* addr); + +/** + * Read list of nameservers to use from the filename given. + * Usually "/etc/resolv.conf". Uses those nameservers as caching proxies. + * If they do not support DNSSEC, validation may fail. + * + * Only nameservers are picked up, the searchdomain, ndots and other + * settings from resolv.conf(5) are ignored. + * + * @param ctx: context. + * At this time it is only possible to set configuration before the + * first resolve is done. + * @param fname: file name string. If NULL "/etc/resolv.conf" is used. + * @return 0 if OK, else error. + */ +int ub_ctx_resolvconf(struct ub_ctx* ctx, const char* fname); + +/** + * Read list of hosts from the filename given. + * Usually "/etc/hosts". + * These addresses are not flagged as DNSSEC secure when queried for. + * + * @param ctx: context. + * At this time it is only possible to set configuration before the + * first resolve is done. + * @param fname: file name string. If NULL "/etc/hosts" is used. + * @return 0 if OK, else error. + */ +int ub_ctx_hosts(struct ub_ctx* ctx, const char* fname); + +/** + * Add a trust anchor to the given context. + * The trust anchor is a string, on one line, that holds a valid DNSKEY or + * DS RR. + * @param ctx: context. + * At this time it is only possible to add trusted keys before the + * first resolve is done. + * @param ta: string, with zone-format RR on one line. + * [domainname] [TTL optional] [type] [class optional] [rdata contents] + * @return 0 if OK, else error. + */ +int ub_ctx_add_ta(struct ub_ctx* ctx, const char* ta); + +/** + * Add trust anchors to the given context. + * Pass name of a file with DS and DNSKEY records (like from dig or drill). + * @param ctx: context. + * At this time it is only possible to add trusted keys before the + * first resolve is done. + * @param fname: filename of file with keyfile with trust anchors. + * @return 0 if OK, else error. + */ +int ub_ctx_add_ta_file(struct ub_ctx* ctx, const char* fname); + +/** + * Add trust anchors to the given context. + * Pass the name of a bind-style config file with trusted-keys{}. + * @param ctx: context. + * At this time it is only possible to add trusted keys before the + * first resolve is done. + * @param fname: filename of file with bind-style config entries with trust + * anchors. + * @return 0 if OK, else error. + */ +int ub_ctx_trustedkeys(struct ub_ctx* ctx, const char* fname); + +/** + * Set debug output (and error output) to the specified stream. + * Pass NULL to disable. Default is stderr. + * @param ctx: context. + * @param out: FILE* out file stream to log to. + * Type void* to avoid stdio dependency of this header file. + * @return 0 if OK, else error. + */ +int ub_ctx_debugout(struct ub_ctx* ctx, void* out); + +/** + * Set debug verbosity for the context + * Output is directed to stderr. + * @param ctx: context. + * @param d: debug level, 0 is off, 1 is very minimal, 2 is detailed, + * and 3 is lots. + * @return 0 if OK, else error. + */ +int ub_ctx_debuglevel(struct ub_ctx* ctx, int d); + +/** + * Set a context behaviour for asynchronous action. + * @param ctx: context. + * @param dothread: if true, enables threading and a call to resolve_async() + * creates a thread to handle work in the background. + * If false, a process is forked to handle work in the background. + * Changes to this setting after async() calls have been made have + * no effect (delete and re-create the context to change). + * @return 0 if OK, else error. + */ +int ub_ctx_async(struct ub_ctx* ctx, int dothread); + +/** + * Poll a context to see if it has any new results + * Do not poll in a loop, instead extract the fd below to poll for readiness, + * and then check, or wait using the wait routine. + * @param ctx: context. + * @return: 0 if nothing to read, or nonzero if a result is available. + * If nonzero, call ctx_process() to do callbacks. + */ +int ub_poll(struct ub_ctx* ctx); + +/** + * Wait for a context to finish with results. Calls ub_process() after + * the wait for you. After the wait, there are no more outstanding + * asynchronous queries. + * @param ctx: context. + * @return: 0 if OK, else error. + */ +int ub_wait(struct ub_ctx* ctx); + +/** + * Get file descriptor. Wait for it to become readable, at this point + * answers are returned from the asynchronous validating resolver. + * Then call the ub_process to continue processing. + * This routine works immediately after context creation, the fd + * does not change. + * @param ctx: context. + * @return: -1 on error, or file descriptor to use select(2) with. + */ +int ub_fd(struct ub_ctx* ctx); + +/** + * Call this routine to continue processing results from the validating + * resolver (when the fd becomes readable). + * Will perform necessary callbacks. + * @param ctx: context + * @return: 0 if OK, else error. + */ +int ub_process(struct ub_ctx* ctx); + +/** + * Perform resolution and validation of the target name. + * @param ctx: context. + * The context is finalized, and can no longer accept config changes. + * @param name: domain name in text format (a zero terminated text string). + * @param rrtype: type of RR in host order, 1 is A (address). + * @param rrclass: class of RR in host order, 1 is IN (for internet). + * @param result: the result data is returned in a newly allocated result + * structure. May be NULL on return, return value is set to an error + * in that case (out of memory). + * @return 0 if OK, else error. + */ +int ub_resolve(struct ub_ctx* ctx, const char* name, int rrtype, + int rrclass, struct ub_result** result); + +/** + * Perform resolution and validation of the target name. + * Asynchronous, after a while, the callback will be called with your + * data and the result. + * @param ctx: context. + * If no thread or process has been created yet to perform the + * work in the background, it is created now. + * The context is finalized, and can no longer accept config changes. + * @param name: domain name in text format (a string). + * @param rrtype: type of RR in host order, 1 is A. + * @param rrclass: class of RR in host order, 1 is IN (for internet). + * @param mydata: this data is your own data (you can pass NULL), + * and is passed on to the callback function. + * @param callback: this is called on completion of the resolution. + * It is called as: + * void callback(void* mydata, int err, struct ub_result* result) + * with mydata: the same as passed here, you may pass NULL, + * with err: is 0 when a result has been found. + * with result: a newly allocated result structure. + * The result may be NULL, in that case err is set. + * + * If an error happens during processing, your callback will be called + * with error set to a nonzero value (and result==NULL). + * @param async_id: if you pass a non-NULL value, an identifier number is + * returned for the query as it is in progress. It can be used to + * cancel the query. + * @return 0 if OK, else error. + */ +int ub_resolve_async(struct ub_ctx* ctx, const char* name, int rrtype, + int rrclass, void* mydata, ub_callback_t callback, int* async_id); + +/** + * Cancel an async query in progress. + * Its callback will not be called. + * + * @param ctx: context. + * @param async_id: which query to cancel. + * @return 0 if OK, else error. + * This routine can return an error if the async_id passed does not exist + * or has already been delivered. If another thread is processing results + * at the same time, the result may be delivered at the same time and the + * cancel fails with an error. Also the cancel can fail due to a system + * error, no memory or socket failures. + */ +int ub_cancel(struct ub_ctx* ctx, int async_id); + +/** + * Free storage associated with a result structure. + * @param result: to free + */ +void ub_resolve_free(struct ub_result* result); + +/** + * Convert error value to a human readable string. + * @param err: error code from one of the ub_val* functions. + * @return pointer to constant text string, zero terminated. + */ +const char* ub_strerror(int err); + +/** + * Debug routine. Print the local zone information to debug output. + * @param ctx: context. Is finalized by the routine. + * @return 0 if OK, else error. + */ +int ub_ctx_print_local_zones(struct ub_ctx* ctx); + +/** + * Add a new zone with the zonetype to the local authority info of the + * library. + * @param ctx: context. Is finalized by the routine. + * @param zone_name: name of the zone in text, "example.com" + * If it already exists, the type is updated. + * @param zone_type: type of the zone (like for unbound.conf) in text. + * @return 0 if OK, else error. + */ +int ub_ctx_zone_add(struct ub_ctx* ctx, const char *zone_name, + const char *zone_type); + +/** + * Remove zone from local authority info of the library. + * @param ctx: context. Is finalized by the routine. + * @param zone_name: name of the zone in text, "example.com" + * If it does not exist, nothing happens. + * @return 0 if OK, else error. + */ +int ub_ctx_zone_remove(struct ub_ctx* ctx, const char *zone_name); + +/** + * Add localdata to the library local authority info. + * Similar to local-data config statement. + * @param ctx: context. Is finalized by the routine. + * @param data: the resource record in text format, for example + * "www.example.com IN A 127.0.0.1" + * @return 0 if OK, else error. + */ +int ub_ctx_data_add(struct ub_ctx* ctx, const char *data); + +/** + * Remove localdata from the library local authority info. + * @param ctx: context. Is finalized by the routine. + * @param data: the name to delete all data from, like "www.example.com". + * @return 0 if OK, else error. + */ +int ub_ctx_data_remove(struct ub_ctx* ctx, const char *data); + +/** + * Get a version string from the libunbound implementation. + * @return a static constant string with the version number. + */ +const char* ub_version(void); + +#ifdef __cplusplus +} +#endif + +#endif /* _UB_UNBOUND_H */ |