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f4ad52dffd
git-svn-id: file:///svn/unbound/trunk@1312 be551aaa-1e26-0410-a405-d3ace91eadb9
554 lines
16 KiB
C
554 lines
16 KiB
C
/*
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* iterator/iter_utils.c - iterative resolver module utility functions.
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*
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* Copyright (c) 2007, NLnet Labs. All rights reserved.
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*
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* This software is open source.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of the NLNET LABS nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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*
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* This file contains functions to assist the iterator module.
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* Configuration options. Forward zones.
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*/
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#include "config.h"
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#include "iterator/iter_utils.h"
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#include "iterator/iterator.h"
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#include "iterator/iter_hints.h"
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#include "iterator/iter_fwd.h"
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#include "iterator/iter_donotq.h"
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#include "iterator/iter_delegpt.h"
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#include "iterator/iter_priv.h"
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#include "services/cache/infra.h"
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#include "services/cache/dns.h"
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#include "services/cache/rrset.h"
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#include "util/net_help.h"
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#include "util/module.h"
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#include "util/log.h"
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#include "util/config_file.h"
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#include "util/regional.h"
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#include "util/data/msgparse.h"
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#include "util/data/dname.h"
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#include "util/random.h"
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#include "util/fptr_wlist.h"
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#include "validator/val_anchor.h"
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/** fillup fetch policy array */
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static void
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fetch_fill(struct iter_env* ie, const char* str)
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{
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char* s = (char*)str, *e;
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int i;
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for(i=0; i<ie->max_dependency_depth+1; i++) {
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ie->target_fetch_policy[i] = strtol(s, &e, 10);
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if(s == e)
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fatal_exit("cannot parse fetch policy number %s", s);
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s = e;
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}
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}
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/** Read config string that represents the target fetch policy */
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static int
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read_fetch_policy(struct iter_env* ie, const char* str)
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{
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int count = cfg_count_numbers(str);
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if(count < 1) {
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log_err("Cannot parse target fetch policy: \"%s\"", str);
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return 0;
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}
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ie->max_dependency_depth = count - 1;
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ie->target_fetch_policy = (int*)calloc(
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(size_t)ie->max_dependency_depth+1, sizeof(int));
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if(!ie->target_fetch_policy) {
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log_err("alloc fetch policy: out of memory");
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return 0;
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}
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fetch_fill(ie, str);
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return 1;
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}
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int
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iter_apply_cfg(struct iter_env* iter_env, struct config_file* cfg)
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{
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int i;
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/* target fetch policy */
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if(!read_fetch_policy(iter_env, cfg->target_fetch_policy))
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return 0;
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for(i=0; i<iter_env->max_dependency_depth+1; i++)
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verbose(VERB_QUERY, "target fetch policy for level %d is %d",
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i, iter_env->target_fetch_policy[i]);
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if(!iter_env->hints)
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iter_env->hints = hints_create();
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if(!iter_env->hints || !hints_apply_cfg(iter_env->hints, cfg)) {
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log_err("Could not set root or stub hints");
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return 0;
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}
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if(!iter_env->fwds)
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iter_env->fwds = forwards_create();
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if(!iter_env->fwds || !forwards_apply_cfg(iter_env->fwds, cfg)) {
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log_err("Could not set forward zones");
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return 0;
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}
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if(!iter_env->donotq)
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iter_env->donotq = donotq_create();
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if(!iter_env->donotq || !donotq_apply_cfg(iter_env->donotq, cfg)) {
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log_err("Could not set donotqueryaddresses");
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return 0;
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}
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if(!iter_env->priv)
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iter_env->priv = priv_create();
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if(!iter_env->priv || !priv_apply_cfg(iter_env->priv, cfg)) {
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log_err("Could not set private addresses");
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return 0;
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}
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iter_env->supports_ipv6 = cfg->do_ip6;
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return 1;
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}
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/** filter out unsuitable targets, return rtt or -1 */
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static int
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iter_filter_unsuitable(struct iter_env* iter_env, struct module_env* env,
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uint8_t* name, size_t namelen, uint16_t qtype, uint32_t now,
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struct delegpt_addr* a)
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{
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int rtt, lame, reclame, dnsseclame;
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if(a->bogus)
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return -1; /* address of server is bogus */
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if(donotq_lookup(iter_env->donotq, &a->addr, a->addrlen)) {
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return -1; /* server is on the donotquery list */
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}
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if(!iter_env->supports_ipv6 && addr_is_ip6(&a->addr, a->addrlen)) {
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return -1; /* there is no ip6 available */
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}
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/* check lameness - need zone , class info */
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if(infra_get_lame_rtt(env->infra_cache, &a->addr, a->addrlen,
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name, namelen, qtype, &lame, &dnsseclame, &reclame,
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&rtt, now)) {
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if(lame)
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return -1; /* server is lame */
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else if(rtt >= USEFUL_SERVER_TOP_TIMEOUT)
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return -1; /* server is unresponsive */
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else if(reclame)
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return rtt+USEFUL_SERVER_TOP_TIMEOUT*2; /* nonpref */
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else if(dnsseclame )
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return rtt+USEFUL_SERVER_TOP_TIMEOUT; /* nonpref */
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else return rtt;
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}
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/* no server information present */
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return UNKNOWN_SERVER_NICENESS;
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}
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/** lookup RTT information, and also store fastest rtt (if any) */
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static int
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iter_fill_rtt(struct iter_env* iter_env, struct module_env* env,
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uint8_t* name, size_t namelen, uint16_t qtype, uint32_t now,
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struct delegpt* dp, int* best_rtt)
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{
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int got_it = 0;
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struct delegpt_addr* a;
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if(dp->bogus)
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return 0; /* NS bogus, all bogus, nothing found */
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for(a=dp->result_list; a; a = a->next_result) {
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a->sel_rtt = iter_filter_unsuitable(iter_env, env,
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name, namelen, qtype, now, a);
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if(a->sel_rtt != -1) {
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if(!got_it) {
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*best_rtt = a->sel_rtt;
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got_it = 1;
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} else if(a->sel_rtt < *best_rtt) {
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*best_rtt = a->sel_rtt;
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}
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}
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}
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return got_it;
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}
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/** filter the addres list, putting best targets at front,
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* returns number of best targets (or 0, no suitable targets) */
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static int
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iter_filter_order(struct iter_env* iter_env, struct module_env* env,
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uint8_t* name, size_t namelen, uint16_t qtype, uint32_t now,
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struct delegpt* dp, int* selected_rtt)
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{
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int got_num = 0, low_rtt = 0, swap_to_front;
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struct delegpt_addr* a, *n, *prev=NULL;
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/* fillup sel_rtt and find best rtt in the bunch */
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got_num = iter_fill_rtt(iter_env, env, name, namelen, qtype, now, dp,
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&low_rtt);
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if(got_num == 0)
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return 0;
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got_num = 0;
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a = dp->result_list;
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while(a) {
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/* skip unsuitable targets */
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if(a->sel_rtt == -1) {
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prev = a;
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a = a->next_result;
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continue;
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}
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/* classify the server address and determine what to do */
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swap_to_front = 0;
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if(a->sel_rtt >= low_rtt && a->sel_rtt - low_rtt <= RTT_BAND) {
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got_num++;
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swap_to_front = 1;
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} else if(a->sel_rtt<low_rtt && low_rtt-a->sel_rtt<=RTT_BAND) {
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got_num++;
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swap_to_front = 1;
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}
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/* swap to front if necessary, or move to next result */
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if(swap_to_front && prev) {
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n = a->next_result;
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prev->next_result = n;
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a->next_result = dp->result_list;
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dp->result_list = a;
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a = n;
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} else {
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prev = a;
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a = a->next_result;
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}
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}
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*selected_rtt = low_rtt;
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return got_num;
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}
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struct delegpt_addr*
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iter_server_selection(struct iter_env* iter_env,
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struct module_env* env, struct delegpt* dp,
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uint8_t* name, size_t namelen, uint16_t qtype, int* dnssec_expected,
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int* chase_to_rd)
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{
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int sel;
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int selrtt;
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struct delegpt_addr* a, *prev;
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int num = iter_filter_order(iter_env, env, name, namelen, qtype,
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*env->now, dp, &selrtt);
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if(num == 0)
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return NULL;
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if(selrtt >= USEFUL_SERVER_TOP_TIMEOUT*2) {
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*chase_to_rd = 1;
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}
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if(selrtt >= USEFUL_SERVER_TOP_TIMEOUT) {
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*dnssec_expected = 0;
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}
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if(num == 1) {
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a = dp->result_list;
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if(++a->attempts < OUTBOUND_MSG_RETRY)
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return a;
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dp->result_list = a->next_result;
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return a;
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}
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/* randomly select a target from the list */
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log_assert(num > 1);
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/* we do not need secure random numbers here, but
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* we do need it to be threadsafe, so we use this */
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sel = ub_random(env->rnd) % num;
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a = dp->result_list;
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prev = NULL;
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while(sel > 0 && a) {
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prev = a;
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a = a->next_result;
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sel--;
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}
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if(!a) /* robustness */
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return NULL;
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if(++a->attempts < OUTBOUND_MSG_RETRY)
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return a;
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/* remove it from the delegation point result list */
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if(prev)
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prev->next_result = a->next_result;
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else dp->result_list = a->next_result;
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return a;
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}
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struct dns_msg*
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dns_alloc_msg(ldns_buffer* pkt, struct msg_parse* msg,
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struct regional* region)
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{
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struct dns_msg* m = (struct dns_msg*)regional_alloc(region,
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sizeof(struct dns_msg));
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if(!m)
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return NULL;
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memset(m, 0, sizeof(*m));
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if(!parse_create_msg(pkt, msg, NULL, &m->qinfo, &m->rep, region)) {
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log_err("malloc failure: allocating incoming dns_msg");
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return NULL;
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}
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return m;
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}
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struct dns_msg*
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dns_copy_msg(struct dns_msg* from, struct regional* region)
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{
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struct dns_msg* m = (struct dns_msg*)regional_alloc(region,
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sizeof(struct dns_msg));
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if(!m)
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return NULL;
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m->qinfo = from->qinfo;
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if(!(m->qinfo.qname = regional_alloc_init(region, from->qinfo.qname,
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from->qinfo.qname_len)))
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return NULL;
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if(!(m->rep = reply_info_copy(from->rep, NULL, region)))
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return NULL;
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return m;
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}
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int
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iter_dns_store(struct module_env* env, struct query_info* msgqinf,
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struct reply_info* msgrep, int is_referral)
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{
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return dns_cache_store(env, msgqinf, msgrep, is_referral);
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}
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int
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iter_ns_probability(struct ub_randstate* rnd, int n, int m)
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{
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int sel;
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if(n == m) /* 100% chance */
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return 1;
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/* we do not need secure random numbers here, but
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* we do need it to be threadsafe, so we use this */
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sel = ub_random(rnd) % m;
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return (sel < n);
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}
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/** detect dependency cycle for query and target */
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static int
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causes_cycle(struct module_qstate* qstate, uint8_t* name, size_t namelen,
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uint16_t t, uint16_t c)
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{
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struct query_info qinf;
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qinf.qname = name;
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qinf.qname_len = namelen;
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qinf.qtype = t;
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qinf.qclass = c;
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fptr_ok(fptr_whitelist_modenv_detect_cycle(
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qstate->env->detect_cycle));
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return (*qstate->env->detect_cycle)(qstate, &qinf,
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(uint16_t)(BIT_RD|BIT_CD), qstate->is_priming);
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}
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void
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iter_mark_cycle_targets(struct module_qstate* qstate, struct delegpt* dp)
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{
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struct delegpt_ns* ns;
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for(ns = dp->nslist; ns; ns = ns->next) {
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if(ns->resolved)
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continue;
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/* see if this ns as target causes dependency cycle */
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if(causes_cycle(qstate, ns->name, ns->namelen,
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LDNS_RR_TYPE_AAAA, qstate->qinfo.qclass) ||
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causes_cycle(qstate, ns->name, ns->namelen,
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LDNS_RR_TYPE_A, qstate->qinfo.qclass)) {
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log_nametypeclass(VERB_QUERY, "skipping target due "
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"to dependency cycle (harden-glue: no may "
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"fix some of the cycles)",
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ns->name, LDNS_RR_TYPE_A,
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qstate->qinfo.qclass);
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ns->resolved = 1;
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}
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}
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}
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int
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iter_dp_is_useless(struct query_info* qinfo, uint16_t qflags,
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struct delegpt* dp)
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{
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struct delegpt_ns* ns;
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/* check:
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* o all NS items are required glue.
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* o no addresses are provided.
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* o RD qflag is on.
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* OR
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* o no addresses are provided.
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* o RD qflag is on.
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* o the query is for one of the nameservers in dp,
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* and that nameserver is a glue-name for this dp.
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*/
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if(!(qflags&BIT_RD))
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return 0;
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/* either available or unused targets */
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if(dp->usable_list || dp->result_list)
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return 0;
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/* see if query is for one of the nameservers, which is glue */
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if( (qinfo->qtype == LDNS_RR_TYPE_A ||
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qinfo->qtype == LDNS_RR_TYPE_AAAA) &&
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dname_subdomain_c(qinfo->qname, dp->name) &&
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delegpt_find_ns(dp, qinfo->qname, qinfo->qname_len))
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return 1;
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for(ns = dp->nslist; ns; ns = ns->next) {
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if(ns->resolved) /* skip failed targets */
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continue;
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if(!dname_subdomain_c(ns->name, dp->name))
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return 0; /* one address is not required glue */
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}
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return 1;
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}
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int
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iter_indicates_dnssec(struct module_env* env, struct delegpt* dp,
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struct dns_msg* msg, uint16_t dclass)
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{
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/* information not available, !env->anchors can be common */
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if(!env || !env->anchors || !dp || !dp->name)
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return 0;
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/* a trust anchor exists with this name, RRSIGs expected */
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if(anchor_find(env->anchors, dp->name, dp->namelabs, dp->namelen,
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dclass))
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return 1;
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/* see if DS rrset was given, in AUTH section */
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if(msg && msg->rep &&
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reply_find_rrset_section_ns(msg->rep, dp->name, dp->namelen,
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LDNS_RR_TYPE_DS, dclass))
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return 1;
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return 0;
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}
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int
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iter_msg_has_dnssec(struct dns_msg* msg)
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{
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size_t i;
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if(!msg || !msg->rep)
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return 0;
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for(i=0; i<msg->rep->an_numrrsets + msg->rep->ns_numrrsets; i++) {
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if(((struct packed_rrset_data*)msg->rep->rrsets[i]->
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entry.data)->rrsig_count > 0)
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return 1;
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}
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/* empty message has no DNSSEC info, with DNSSEC the reply is
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* not empty (NSEC) */
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return 0;
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}
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int iter_msg_from_zone(struct dns_msg* msg, struct delegpt* dp,
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enum response_type type, uint16_t dclass)
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{
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if(!msg || !dp || !msg->rep || !dp->name)
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return 0;
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/* SOA RRset - always from reply zone */
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if(reply_find_rrset_section_an(msg->rep, dp->name, dp->namelen,
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LDNS_RR_TYPE_SOA, dclass) ||
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reply_find_rrset_section_ns(msg->rep, dp->name, dp->namelen,
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LDNS_RR_TYPE_SOA, dclass))
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return 1;
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if(type == RESPONSE_TYPE_REFERRAL) {
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size_t i;
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/* if it adds a single label, i.e. we expect .com,
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* and referral to example.com. NS ... , then origin zone
|
|
* is .com. For a referral to sub.example.com. NS ... then
|
|
* we do not know, since example.com. may be in between. */
|
|
for(i=0; i<msg->rep->an_numrrsets+msg->rep->ns_numrrsets;
|
|
i++) {
|
|
struct ub_packed_rrset_key* s = msg->rep->rrsets[i];
|
|
if(ntohs(s->rk.type) == LDNS_RR_TYPE_NS &&
|
|
ntohs(s->rk.rrset_class) == dclass) {
|
|
int l = dname_count_labels(s->rk.dname);
|
|
if(l == dp->namelabs + 1 &&
|
|
dname_strict_subdomain(s->rk.dname,
|
|
l, dp->name, dp->namelabs))
|
|
return 1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
log_assert(type==RESPONSE_TYPE_ANSWER || type==RESPONSE_TYPE_CNAME);
|
|
/* not a referral, and not lame delegation (upwards), so,
|
|
* any NS rrset must be from the zone itself */
|
|
if(reply_find_rrset_section_an(msg->rep, dp->name, dp->namelen,
|
|
LDNS_RR_TYPE_NS, dclass) ||
|
|
reply_find_rrset_section_ns(msg->rep, dp->name, dp->namelen,
|
|
LDNS_RR_TYPE_NS, dclass))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* check equality of two rrsets
|
|
* @param k1: rrset
|
|
* @param k2: rrset
|
|
* @return true if equal
|
|
*/
|
|
static int
|
|
rrset_equal(struct ub_packed_rrset_key* k1, struct ub_packed_rrset_key* k2)
|
|
{
|
|
struct packed_rrset_data* d1 = (struct packed_rrset_data*)
|
|
k1->entry.data;
|
|
struct packed_rrset_data* d2 = (struct packed_rrset_data*)
|
|
k2->entry.data;
|
|
size_t i, t;
|
|
if(k1->rk.dname_len != k2->rk.dname_len ||
|
|
k1->rk.flags != k2->rk.flags ||
|
|
k1->rk.type != k2->rk.type ||
|
|
k1->rk.rrset_class != k2->rk.rrset_class ||
|
|
query_dname_compare(k1->rk.dname, k2->rk.dname) != 0)
|
|
return 0;
|
|
if(d1->ttl != d2->ttl ||
|
|
d1->count != d2->count ||
|
|
d1->rrsig_count != d2->rrsig_count ||
|
|
d1->trust != d2->trust ||
|
|
d1->security != d2->security)
|
|
return 0;
|
|
t = d1->count + d1->rrsig_count;
|
|
for(i=0; i<t; i++) {
|
|
if(d1->rr_len[i] != d2->rr_len[i] ||
|
|
d1->rr_ttl[i] != d2->rr_ttl[i] ||
|
|
memcmp(d1->rr_data[i], d2->rr_data[i],
|
|
d1->rr_len[i]) != 0)
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
int
|
|
reply_equal(struct reply_info* p, struct reply_info* q)
|
|
{
|
|
size_t i;
|
|
if(p->flags != q->flags ||
|
|
p->qdcount != q->qdcount ||
|
|
p->ttl != q->ttl ||
|
|
p->security != q->security ||
|
|
p->an_numrrsets != q->an_numrrsets ||
|
|
p->ns_numrrsets != q->ns_numrrsets ||
|
|
p->ar_numrrsets != q->ar_numrrsets ||
|
|
p->rrset_count != q->rrset_count)
|
|
return 0;
|
|
for(i=0; i<p->rrset_count; i++) {
|
|
if(!rrset_equal(p->rrsets[i], q->rrsets[i]))
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|