iterator.h

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/*
 * iterator/iterator.h - iterative resolver DNS query response module
 *
 * 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.
 */

 
#ifndef ITERATOR_ITERATOR_H
#define ITERATOR_ITERATOR_H
#include "services/outbound_list.h"
#include "util/data/msgreply.h"
#include "util/module.h"
struct delegpt;
struct iter_hints;
struct iter_forwards;
struct iter_donotq;
struct iter_prep_list;
struct iter_priv;
struct rbtree_type;

#define MAX_TARGET_COUNT    64
#define MAX_RESTART_COUNT       8
#define MAX_REFERRAL_COUNT  130
#define MAX_SENT_COUNT      32
#define DNSSEC_LAME_DETECT_COUNT 4
#define MAX_MINIMISE_COUNT  10
/* max number of time-outs for minimised query. Prevents resolving failures
 * when the QNAME minimisation QTYPE is blocked. */
#define MAX_MINIMISE_TIMEOUT_COUNT 3
#define MINIMISE_ONE_LAB    4
#define MINIMISE_MULTIPLE_LABS  (MAX_MINIMISE_COUNT - MINIMISE_ONE_LAB)
#define TARGET_FETCH_STOP   3
#define UNKNOWN_SERVER_NICENESS 376
#define USEFUL_SERVER_TOP_TIMEOUT   120000
#define OUTBOUND_MSG_RETRY 5
#define RTT_BAND 400
#define INFRA_BACKOFF_INITIAL 240

struct iter_env {
    int supports_ipv6;

    int supports_ipv4;

    struct iter_donotq* donotq;

    struct iter_priv* priv;

    struct rbtree_type* caps_white;

    int max_dependency_depth;

    int* target_fetch_policy;

    lock_basic_type queries_ratelimit_lock;
    size_t num_queries_ratelimited;
};

enum minimisation_state {
    INIT_MINIMISE_STATE = 0,
    MINIMISE_STATE,
    SKIP_MINIMISE_STATE,
    DONOT_MINIMISE_STATE,
};

enum iter_state {
    INIT_REQUEST_STATE = 0,

    INIT_REQUEST_2_STATE,

    INIT_REQUEST_3_STATE,

    QUERYTARGETS_STATE,

    QUERY_RESP_STATE,

    PRIME_RESP_STATE,

    COLLECT_CLASS_STATE,

    DSNS_FIND_STATE,

    FINISHED_STATE
};

struct iter_qstate {
    enum iter_state state;

    enum iter_state final_state;

    int depth;

    struct dns_msg* response;

    struct iter_prep_list* an_prepend_list;
    struct iter_prep_list* an_prepend_last;

    struct iter_prep_list* ns_prepend_list;
    struct iter_prep_list* ns_prepend_last;

    struct query_info qchase;
    uint16_t chase_flags;
    int chase_to_rd;

    struct delegpt* dp;

    int caps_fallback;
    size_t caps_server;
    struct reply_info* caps_reply;
    struct dns_msg* caps_response;

    struct dns_msg* deleg_msg;

    int num_target_queries;

    int num_current_queries;

    int query_restart_count;

    int referral_count;

    int sent_count;
    
    int* target_count;

    int ratelimit_ok;

    struct delegpt* store_parent_NS;

    int query_for_pside_glue;
    struct ub_packed_rrset_key* pside_glue;

    uint8_t* dsns_point;
    size_t dsns_point_len;

    int dnssec_expected;

    int dnssec_lame_query;

    int wait_priming_stub;

    int refetch_glue;

    struct outbound_list outlist;

    enum minimisation_state minimisation_state;

    struct query_info qinfo_out;

    int minimise_count;

    int minimise_timeout_count;

    int auth_zone_response;
    int auth_zone_avoid;
};

struct iter_prep_list {
    struct iter_prep_list* next;
    struct ub_packed_rrset_key* rrset;
};

struct module_func_block* iter_get_funcblock(void);

const char* iter_state_to_string(enum iter_state state);

int iter_state_is_responsestate(enum iter_state s);

int iter_init(struct module_env* env, int id);

void iter_deinit(struct module_env* env, int id);

void iter_operate(struct module_qstate* qstate, enum module_ev event, int id,
    struct outbound_entry* outbound);

void iter_inform_super(struct module_qstate* qstate, int id, 
    struct module_qstate* super);

void iter_clear(struct module_qstate* qstate, int id);

size_t iter_get_mem(struct module_env* env, int id);
 
#endif /* ITERATOR_ITERATOR_H */