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      1 /*
      2  * libunbound/libworker.h - worker thread or process that resolves
      3  *
      4  * Copyright (c) 2007, NLnet Labs. All rights reserved.
      5  *
      6  * This software is open source.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  *
     12  * Redistributions of source code must retain the above copyright notice,
     13  * this list of conditions and the following disclaimer.
     14  *
     15  * Redistributions in binary form must reproduce the above copyright notice,
     16  * this list of conditions and the following disclaimer in the documentation
     17  * and/or other materials provided with the distribution.
     18  *
     19  * Neither the name of the NLNET LABS nor the names of its contributors may
     20  * be used to endorse or promote products derived from this software without
     21  * specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     34  */
     35 
     36 /**
     37  * \file
     38  *
     39  * This file contains the worker process or thread that performs
     40  * the DNS resolving and validation. The worker is called by a procedure
     41  * and if in the background continues until exit, if in the foreground
     42  * returns from the procedure when done.
     43  */
     44 #ifndef LIBUNBOUND_LIBWORKER_H
     45 #define LIBUNBOUND_LIBWORKER_H
     46 #include "util/data/packed_rrset.h"
     47 struct ub_ctx;
     48 struct ub_result;
     49 struct module_env;
     50 struct comm_base;
     51 struct outside_network;
     52 struct ub_randstate;
     53 struct ctx_query;
     54 struct outbound_entry;
     55 struct module_qstate;
     56 struct comm_point;
     57 struct comm_reply;
     58 struct regional;
     59 struct tube;
     60 struct sldns_buffer;
     61 struct ub_event_base;
     62 struct query_info;
     63 
     64 /**
     65  * The library-worker status structure
     66  * Internal to the worker.
     67  */
     68 struct libworker {
     69 	/** every worker has a unique thread_num. (first in struct) */
     70 	int thread_num;
     71 	/** context we are operating under */
     72 	struct ub_ctx* ctx;
     73 
     74 	/** is this the bg worker? */
     75 	int is_bg;
     76 	/** is this a bg worker that is threaded (not forked)? */
     77 	int is_bg_thread;
     78 	/** want to quit, stop handling new content */
     79 	int want_quit;
     80 
     81 	/** copy of the module environment with worker local entries. */
     82 	struct module_env* env;
     83 	/** the event base this worker works with */
     84 	struct comm_base* base;
     85 	/** the backside outside network interface to the auth servers */
     86 	struct outside_network* back;
     87 	/** random() table for this worker. */
     88 	struct ub_randstate* rndstate;
     89 	/** sslcontext for SSL wrapped DNS over TCP queries */
     90 	void* sslctx;
     91 };
     92 
     93 /**
     94  * Create a background worker
     95  * @param ctx: is updated with pid/tid of the background worker.
     96  *	a new allocation cache is obtained from ctx. It contains the
     97  *	threadnumber and unique id for further (shared) cache insertions.
     98  * @return 0 if OK, else error.
     99  *	Further communication is done via the pipes in ctx.
    100  */
    101 int libworker_bg(struct ub_ctx* ctx);
    102 
    103 /**
    104  * Create a foreground worker.
    105  * This worker will join the threadpool of resolver threads.
    106  * It exits when the query answer has been obtained (or error).
    107  * This routine blocks until the worker is finished.
    108  * @param ctx: new allocation cache obtained and returned to it.
    109  * @param q: query (result is stored in here).
    110  * @return 0 if finished OK, else error.
    111  */
    112 int libworker_fg(struct ub_ctx* ctx, struct ctx_query* q);
    113 
    114 /**
    115  * create worker for event-based interface.
    116  * @param ctx: context with config.
    117  * @param eb: event base.
    118  * @return new worker or NULL.
    119  */
    120 struct libworker* libworker_create_event(struct ub_ctx* ctx,
    121 	struct ub_event_base* eb);
    122 
    123 /**
    124  * Attach context_query to mesh for callback in event-driven setup.
    125  * @param ctx: context
    126  * @param q: context query entry
    127  * @param async_id: store query num if query takes long.
    128  * @return 0 if finished OK, else error.
    129  */
    130 int libworker_attach_mesh(struct ub_ctx* ctx, struct ctx_query* q,
    131 	int* async_id);
    132 
    133 /**
    134  * delete worker for event-based interface.  does not free the event_base.
    135  * @param w: event-based worker to delete.
    136  */
    137 void libworker_delete_event(struct libworker* w);
    138 
    139 /** cleanup the cache to remove all rrset IDs from it, arg is libworker */
    140 void libworker_alloc_cleanup(void* arg);
    141 
    142 /**
    143  * fill result from parsed message, on error fills servfail
    144  * @param res: is clear at start, filled in at end.
    145  * @param buf: contains DNS message.
    146  * @param temp: temporary buffer for parse.
    147  * @param msg_security: security status of the DNS message.
    148  *   On error, the res may contain a different status
    149  *   (out of memory is not secure, not bogus).
    150  */
    151 void libworker_enter_result(struct ub_result* res, struct sldns_buffer* buf,
    152 	struct regional* temp, enum sec_status msg_security);
    153 
    154 #endif /* LIBUNBOUND_LIBWORKER_H */
    155