/*
 * libunbound/worker.h - worker thread or process that resolves
 *
 * 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 worker process or thread that performs
 * the DNS resolving and validation. The worker is called by a procedure
 * and if in the background continues until exit, if in the foreground
 * returns from the procedure when done.
 */
#ifndef LIBUNBOUND_LIBWORKER_H
#define LIBUNBOUND_LIBWORKER_H
#include "util/data/packed_rrset.h"
struct ub_ctx;
struct ub_result;
struct module_env;
struct comm_base;
struct outside_network;
struct ub_randstate;
struct ctx_query;
struct outbound_entry;
struct module_qstate;
struct comm_point;
struct comm_reply;
struct regional;
struct tube;

/** 
 * The library-worker status structure
 * Internal to the worker.
 */
struct libworker {
	/** every worker has a unique thread_num. (first in struct) */
	int thread_num;
	/** context we are operating under */
	struct ub_ctx* ctx;

	/** is this the bg worker? */
	int is_bg;
	/** is this a bg worker that is threaded (not forked)? */
	int is_bg_thread;

	/** copy of the module environment with worker local entries. */
	struct module_env* env;
	/** the event base this worker works with */
	struct comm_base* base;
	/** the backside outside network interface to the auth servers */
	struct outside_network* back;
	/** random() table for this worker. */
	struct ub_randstate* rndstate;
	/** sslcontext for SSL wrapped DNS over TCP queries */
	void* sslctx;
};

/**
 * Create a background worker
 * @param ctx: is updated with pid/tid of the background worker.
 *	a new allocation cache is obtained from ctx. It contains the
 *	threadnumber and unique id for further (shared) cache insertions.
 * @return 0 if OK, else error.
 *	Further communication is done via the pipes in ctx. 
 */
int libworker_bg(struct ub_ctx* ctx);

/**
 * Create a foreground worker.
 * This worker will join the threadpool of resolver threads.
 * It exits when the query answer has been obtained (or error).
 * This routine blocks until the worker is finished.
 * @param ctx: new allocation cache obtained and returned to it.
 * @param q: query (result is stored in here).
 * @return 0 if finished OK, else error.
 */
int libworker_fg(struct ub_ctx* ctx, struct ctx_query* q);

/** cleanup the cache to remove all rrset IDs from it, arg is libworker */
void libworker_alloc_cleanup(void* arg);

/**
 * Worker service routine to send serviced queries to authoritative servers.
 * @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 DO bit set.
 * @param want_dnssec: signatures needed.
 * @param addr: where to.
 * @param addrlen: length of addr.
 * @param zone: delegation point name.
 * @param zonelen: length of zone name wireformat dname.
 * @param q: wich query state to reactivate upon return.
 * @return: false on failure (memory or socket related). no query was
 *      sent.
 */
struct outbound_entry* libworker_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);

/** process incoming replies from the network */
int libworker_handle_reply(struct comm_point* c, void* arg, int error,
        struct comm_reply* reply_info);

/** process incoming serviced query replies from the network */
int libworker_handle_service_reply(struct comm_point* c, void* arg, int error,
        struct comm_reply* reply_info);

/** handle control command coming into server */
void libworker_handle_control_cmd(struct tube* tube, uint8_t* msg, size_t len,
	int err, void* arg);

/** handle opportunity to write result back */
void libworker_handle_result_write(struct tube* tube, uint8_t* msg, size_t len,
	int err, void* arg);

/** mesh callback with fg results */
void libworker_fg_done_cb(void* arg, int rcode, ldns_buffer* buf, 
	enum sec_status s, char* why_bogus);

/** mesh callback with bg results */
void libworker_bg_done_cb(void* arg, int rcode, ldns_buffer* buf, 
	enum sec_status s, char* why_bogus);

/** 
 * fill result from parsed message, on error fills servfail 
 * @param res: is clear at start, filled in at end.
 * @param buf: contains DNS message.
 * @param temp: temporary buffer for parse.
 * @param msg_security: security status of the DNS message.
 *   On error, the res may contain a different status 
 *   (out of memory is not secure, not bogus).
 */
void libworker_enter_result(struct ub_result* res, ldns_buffer* buf,
	struct regional* temp, enum sec_status msg_security);

#endif /* LIBUNBOUND_LIBWORKER_H */