vendor/unbound/1.4.17

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+/*
+ * util/module.h - DNS handling module interface
+ *
+ * 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 REGENTS 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 the interface for DNS handling modules.
+ */
+
+#ifndef UTIL_MODULE_H
+#define UTIL_MODULE_H
+#include "util/storage/lruhash.h"
+#include "util/data/msgreply.h"
+#include "util/data/msgparse.h"
+struct alloc_cache;
+struct rrset_cache;
+struct key_cache;
+struct config_file;
+struct slabhash;
+struct query_info;
+struct edns_data;
+struct regional;
+struct worker;
+struct module_qstate;
+struct ub_randstate;
+struct mesh_area;
+struct mesh_state;
+struct val_anchors;
+struct val_neg_cache;
+struct iter_forwards;
+struct iter_hints;
+
+/** Maximum number of modules in operation */
+#define MAX_MODULE 5
+
+/**
+ * Module environment.
+ * Services and data provided to the module.
+ */
+struct module_env {
+	/* --- data --- */
+	/** config file with config options */
+	struct config_file* cfg;
+	/** shared message cache */
+	struct slabhash* msg_cache;
+	/** shared rrset cache */
+	struct rrset_cache* rrset_cache;
+	/** shared infrastructure cache (edns, lameness) */
+	struct infra_cache* infra_cache;
+	/** shared key cache */
+	struct key_cache* key_cache;
+
+	/* --- services --- */
+	/** 
+	 * Send serviced DNS query to server. UDP/TCP and EDNS is handled.
+	 * operate() should return with wait_reply. Later on a callback 
+	 * will cause operate() to be called with event timeout or reply.
+	 * The time until a timeout is calculated from roundtrip timing,
+	 * several UDP retries are attempted.
+	 * @param qname: query name. (host order)
+	 * @param qnamelen: length in bytes of qname, including trailing 0.
+	 * @param qtype: query type. (host order)
+	 * @param qclass: query class. (host order)
+	 * @param flags: host order flags word, with opcode and CD bit.
+	 * @param dnssec: if set, EDNS record will have bits set.
+	 *	If EDNS_DO bit is set, DO bit is set in EDNS records.
+	 *	If BIT_CD is set, CD bit is set in queries with EDNS records.
+	 * @param want_dnssec: if set, the validator wants DNSSEC.  Without
+	 * 	EDNS, the answer is likely to be useless for this domain.
+	 * @param addr: where to.
+	 * @param addrlen: length of addr.
+	 * @param zone: delegation point name.
+	 * @param zonelen: length of zone name.
+	 * @param q: wich query state to reactivate upon return.
+	 * @return: false on failure (memory or socket related). no query was
+	 *	sent. Or returns an outbound entry with qsent and qstate set.
+	 *	This outbound_entry will be used on later module invocations
+	 *	that involve this query (timeout, error or reply).
+	 */
+	struct outbound_entry* (*send_query)(uint8_t* qname, size_t qnamelen, 
+		uint16_t qtype, uint16_t qclass, uint16_t flags, int dnssec, 
+		int want_dnssec, struct sockaddr_storage* addr, 
+		socklen_t addrlen, uint8_t* zone, size_t zonelen,
+		struct module_qstate* q);
+
+	/**
+	 * Detach-subqueries.
+	 * Remove all sub-query references from this query state.
+	 * Keeps super-references of those sub-queries correct.
+	 * Updates stat items in mesh_area structure.
+	 * @param qstate: used to find mesh state.
+	 */
+	void (*detach_subs)(struct module_qstate* qstate);
+
+	/**
+	 * Attach subquery.
+	 * Creates it if it does not exist already.
+	 * Keeps sub and super references correct.
+	 * Updates stat items in mesh_area structure.
+	 * Pass if it is priming query or not.
+	 * return:
+	 * o if error (malloc) happened.
+	 * o need to initialise the new state (module init; it is a new state).
+	 *   so that the next run of the query with this module is successful.
+	 * o no init needed, attachment successful.
+	 * 
+	 * @param qstate: the state to find mesh state, and that wants to 
+	 * 	receive the results from the new subquery.
+	 * @param qinfo: what to query for (copied).
+	 * @param qflags: what flags to use (RD, CD flag or not).
+	 * @param prime: if it is a (stub) priming query.
+	 * @param newq: If the new subquery needs initialisation, it is 
+	 * 	returned, otherwise NULL is returned.
+	 * @return: false on error, true if success (and init may be needed).
+	 */ 
+	int (*attach_sub)(struct module_qstate* qstate, 
+		struct query_info* qinfo, uint16_t qflags, int prime, 
+		struct module_qstate** newq);
+
+	/**
+	 * Kill newly attached sub. If attach_sub returns newq for 
+	 * initialisation, but that fails, then this routine will cleanup and
+	 * delete the fresly created sub.
+	 * @param newq: the new subquery that is no longer needed.
+	 * 	It is removed.
+	 */
+	void (*kill_sub)(struct module_qstate* newq);
+
+	/**
+	 * Detect if adding a dependency for qstate on name,type,class will
+	 * create a dependency cycle.
+	 * @param qstate: given mesh querystate.
+	 * @param qinfo: query info for dependency. 
+	 * @param flags: query flags of dependency, RD/CD flags.
+	 * @param prime: if dependency is a priming query or not.
+	 * @return true if the name,type,class exists and the given 
+	 * 	qstate mesh exists as a dependency of that name. Thus 
+	 * 	if qstate becomes dependent on name,type,class then a 
+	 * 	cycle is created.
+	 */
+	int (*detect_cycle)(struct module_qstate* qstate, 
+		struct query_info* qinfo, uint16_t flags, int prime);
+
+	/** region for temporary usage. May be cleared after operate() call. */
+	struct regional* scratch;
+	/** buffer for temporary usage. May be cleared after operate() call. */
+	ldns_buffer* scratch_buffer;
+	/** internal data for daemon - worker thread. */
+	struct worker* worker;
+	/** mesh area with query state dependencies */
+	struct mesh_area* mesh;
+	/** allocation service */
+	struct alloc_cache* alloc;
+	/** random table to generate random numbers */
+	struct ub_randstate* rnd;
+	/** time in seconds, converted to integer */
+	uint32_t* now;
+	/** time in microseconds. Relatively recent. */
+	struct timeval* now_tv;
+	/** is validation required for messages, controls client-facing
+	 * validation status (AD bits) and servfails */
+	int need_to_validate;
+	/** trusted key storage; these are the configured keys, if not NULL,
+	 * otherwise configured by validator. These are the trust anchors,
+	 * and are not primed and ready for validation, but on the bright
+	 * side, they are read only memory, thus no locks and fast. */
+	struct val_anchors* anchors;
+	/** negative cache, configured by the validator. if not NULL,
+	 * contains NSEC record lookup trees. */
+	struct val_neg_cache* neg_cache;
+	/** the 5011-probe timer (if any) */
+	struct comm_timer* probe_timer;
+	/** Mapping of forwarding zones to targets.
+	 * iterator forwarder information. per-thread, created by worker */
+	struct iter_forwards* fwds;
+	/** 
+	 * iterator forwarder information. per-thread, created by worker.
+	 * The hints -- these aren't stored in the cache because they don't 
+	 * expire. The hints are always used to "prime" the cache. Note 
+	 * that both root hints and stub zone "hints" are stored in this 
+	 * data structure. 
+	 */
+	struct iter_hints* hints;
+	/** module specific data. indexed by module id. */
+	void* modinfo[MAX_MODULE];
+};
+
+/**
+ * External visible states of the module state machine 
+ * Modules may also have an internal state.
+ * Modules are supposed to run to completion or until blocked.
+ */
+enum module_ext_state {
+	/** initial state - new query */
+	module_state_initial = 0,
+	/** waiting for reply to outgoing network query */
+	module_wait_reply,
+	/** module is waiting for another module */
+	module_wait_module,
+	/** module is waiting for another module; that other is restarted */
+	module_restart_next,
+	/** module is waiting for sub-query */
+	module_wait_subquery,
+	/** module could not finish the query */
+	module_error,
+	/** module is finished with query */
+	module_finished
+};
+
+/**
+ * Events that happen to modules, that start or wakeup modules.
+ */
+enum module_ev {
+	/** new query */
+	module_event_new = 0,
+	/** query passed by other module */
+	module_event_pass,
+	/** reply inbound from server */
+	module_event_reply,
+	/** no reply, timeout or other error */
+	module_event_noreply,
+	/** reply is there, but capitalisation check failed */
+	module_event_capsfail,
+	/** next module is done, and its reply is awaiting you */
+	module_event_moddone,
+	/** error */
+	module_event_error
+};
+
+/** 
+ * Linked list of sockaddrs 
+ * May be allocated such that only 'len' bytes of addr exist for the structure.
+ */
+struct sock_list {
+	/** next in list */
+	struct sock_list* next;
+	/** length of addr */
+	socklen_t len;
+	/** sockaddr */
+	struct sockaddr_storage addr;
+};
+
+/**
+ * Module state, per query.
+ */
+struct module_qstate {
+	/** which query is being answered: name, type, class */
+	struct query_info qinfo;
+	/** flags uint16 from query */
+	uint16_t query_flags;
+	/** if this is a (stub or root) priming query (with hints) */
+	int is_priming;
+
+	/** comm_reply contains server replies */
+	struct comm_reply* reply;
+	/** the reply message, with message for client and calling module */
+	struct dns_msg* return_msg;
+	/** the rcode, in case of error, instead of a reply message */
+	int return_rcode;
+	/** origin of the reply (can be NULL from cache, list for cnames) */
+	struct sock_list* reply_origin;
+	/** IP blacklist for queries */
+	struct sock_list* blacklist;
+	/** region for this query. Cleared when query process finishes. */
+	struct regional* region;
+	/** failure reason information if val-log-level is high */
+	struct config_strlist* errinf;
+
+	/** which module is executing */
+	int curmod;
+	/** module states */
+	enum module_ext_state ext_state[MAX_MODULE];
+	/** module specific data for query. indexed by module id. */
+	void* minfo[MAX_MODULE];
+	/** environment for this query */
+	struct module_env* env;
+	/** mesh related information for this query */
+	struct mesh_state* mesh_info;
+	/** how many seconds before expiry is this prefetched (0 if not) */
+	uint32_t prefetch_leeway;
+};
+
+/** 
+ * Module functionality block
+ */
+struct module_func_block {
+	/** text string name of module */
+	const char* name;
+
+	/** 
+	 * init the module. Called once for the global state.
+	 * This is the place to apply settings from the config file.
+	 * @param env: module environment.
+	 * @param id: module id number.
+	 * return: 0 on error
+	 */
+	int (*init)(struct module_env* env, int id);
+
+	/**
+	 * de-init, delete, the module. Called once for the global state.
+	 * @param env: module environment.
+	 * @param id: module id number.
+	 */
+	void (*deinit)(struct module_env* env, int id);
+
+	/**
+	 * accept a new query, or work further on existing query.
+	 * Changes the qstate->ext_state to be correct on exit.
+	 * @param ev: event that causes the module state machine to 
+	 *	(re-)activate.
+	 * @param qstate: the query state. 
+	 *	Note that this method is not allowed to change the
+	 *	query state 'identity', that is query info, qflags,
+	 *	and priming status.
+	 *	Attach a subquery to get results to a different query.
+	 * @param id: module id number that operate() is called on. 
+	 * @param outbound: if not NULL this event is due to the reply/timeout
+	 *	or error on this outbound query.
+	 * @return: if at exit the ext_state is:
+	 *	o wait_module: next module is started. (with pass event).
+	 *	o error or finished: previous module is resumed.
+	 *	o otherwise it waits until that event happens (assumes
+	 *	  the service routine to make subrequest or send message
+	 *	  have been called.
+	 */
+	void (*operate)(struct module_qstate* qstate, enum module_ev event, 
+		int id, struct outbound_entry* outbound);
+
+	/**
+	 * inform super querystate about the results from this subquerystate.
+	 * Is called when the querystate is finished.  The method invoked is
+	 * the one from the current module active in the super querystate.
+	 * @param qstate: the query state that is finished.
+	 *	Examine return_rcode and return_reply in the qstate.
+	 * @param id: module id for this module.
+	 *	This coincides with the current module for the super qstate.
+	 * @param super: the super querystate that needs to be informed.
+	 */
+	void (*inform_super)(struct module_qstate* qstate, int id,
+		struct module_qstate* super);
+
+	/**
+	 * clear module specific data
+	 */
+	void (*clear)(struct module_qstate* qstate, int id);
+
+	/**
+	 * How much memory is the module specific data using. 
+	 * @param env: module environment.
+	 * @param id: the module id.
+	 * @return the number of bytes that are alloced.
+	 */
+	size_t (*get_mem)(struct module_env* env, int id);
+};
+
+/** 
+ * Debug utility: module external qstate to string 
+ * @param s: the state value.
+ * @return descriptive string.
+ */
+const char* strextstate(enum module_ext_state s);
+
+/** 
+ * Debug utility: module event to string 
+ * @param e: the module event value.
+ * @return descriptive string.
+ */
+const char* strmodulevent(enum module_ev e);
+
+#endif /* UTIL_MODULE_H */