385 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			385 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			C++
		
	
	
	
| /*
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|  * Copyright (C) 2019 The Android Open Source Project
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|  *
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|  * Licensed under the Apache License, Version 2.0 (the "License");
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|  * you may not use this file except in compliance with the License.
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|  * You may obtain a copy of the License at
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|  *
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|  *      http://www.apache.org/licenses/LICENSE-2.0
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|  *
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|  * Unless required by applicable law or agreed to in writing, software
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|  * distributed under the License is distributed on an "AS IS" BASIS,
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|  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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|  * See the License for the specific language governing permissions and
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|  * limitations under the License.
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|  */
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| 
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| #define LOG_TAG "resolv"
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| 
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| #include "ResolverController.h"
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| 
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| #include <set>
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| #include <string>
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| #include <vector>
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| 
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| #include <aidl/android/net/IDnsResolver.h>
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| #include <android-base/logging.h>
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| #include <android-base/strings.h>
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| 
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| #include "Dns64Configuration.h"
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| #include "DnsResolver.h"
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| #include "DnsTlsDispatcher.h"
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| #include "PrivateDnsConfiguration.h"
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| #include "ResolverEventReporter.h"
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| #include "ResolverStats.h"
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| #include "resolv_cache.h"
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| #include "stats.h"
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| #include "util.h"
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| 
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| using aidl::android::net::ResolverParamsParcel;
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| using aidl::android::net::resolv::aidl::IDnsResolverUnsolicitedEventListener;
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| using aidl::android::net::resolv::aidl::Nat64PrefixEventParcel;
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| 
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| namespace android {
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| 
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| using netdutils::DumpWriter;
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| 
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| namespace net {
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| 
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| namespace {
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| 
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| void sendNat64PrefixEvent(const Dns64Configuration::Nat64PrefixInfo& args) {
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|     LOG(DEBUG) << "Sending Nat64Prefix " << (args.added ? "added" : "removed") << " event on netId "
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|                << args.netId << " with prefix " << args.prefixString << "/"
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|                << (int)(args.prefixLength);
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|     // Send a nat64 prefix event to NetdEventListenerService.
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|     const auto& listeners = ResolverEventReporter::getInstance().getListeners();
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|     if (listeners.empty()) {
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|         LOG(ERROR) << __func__ << ": No available listener. Skipping NAT64 prefix event";
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|     }
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|     for (const auto& it : listeners) {
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|         it->onNat64PrefixEvent(args.netId, args.added, args.prefixString, args.prefixLength);
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|     }
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| 
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|     const auto& unsolEventListeners = ResolverEventReporter::getInstance().getUnsolEventListeners();
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|     const Nat64PrefixEventParcel nat64PrefixEvent = {
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|             .netId = static_cast<int32_t>(args.netId),
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|             .prefixOperation =
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|                     args.added ? IDnsResolverUnsolicitedEventListener::PREFIX_OPERATION_ADDED
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|                                : IDnsResolverUnsolicitedEventListener::PREFIX_OPERATION_REMOVED,
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|             .prefixAddress = args.prefixString,
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|             .prefixLength = args.prefixLength,
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|     };
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|     for (const auto& it : unsolEventListeners) {
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|         it->onNat64PrefixEvent(nat64PrefixEvent);
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|     }
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| }
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| 
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| int getDnsInfo(unsigned netId, std::vector<std::string>* servers, std::vector<std::string>* domains,
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|                res_params* params, std::vector<android::net::ResolverStats>* stats,
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|                std::vector<int32_t>* wait_for_pending_req_timeout_count) {
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|     using aidl::android::net::IDnsResolver;
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|     using android::net::ResolverStats;
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|     static_assert(ResolverStats::STATS_SUCCESSES == IDnsResolver::RESOLVER_STATS_SUCCESSES &&
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|                           ResolverStats::STATS_ERRORS == IDnsResolver::RESOLVER_STATS_ERRORS &&
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|                           ResolverStats::STATS_TIMEOUTS == IDnsResolver::RESOLVER_STATS_TIMEOUTS &&
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|                           ResolverStats::STATS_INTERNAL_ERRORS ==
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|                                   IDnsResolver::RESOLVER_STATS_INTERNAL_ERRORS &&
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|                           ResolverStats::STATS_RTT_AVG == IDnsResolver::RESOLVER_STATS_RTT_AVG &&
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|                           ResolverStats::STATS_LAST_SAMPLE_TIME ==
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|                                   IDnsResolver::RESOLVER_STATS_LAST_SAMPLE_TIME &&
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|                           ResolverStats::STATS_USABLE == IDnsResolver::RESOLVER_STATS_USABLE &&
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|                           ResolverStats::STATS_COUNT == IDnsResolver::RESOLVER_STATS_COUNT,
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|                   "AIDL and ResolverStats.h out of sync");
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|     int nscount = -1;
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|     sockaddr_storage res_servers[MAXNS];
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|     int dcount = -1;
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|     char res_domains[MAXDNSRCH][MAXDNSRCHPATH];
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|     res_stats res_stats[MAXNS];
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|     servers->clear();
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|     domains->clear();
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|     *params = res_params{};
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|     stats->clear();
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|     int res_wait_for_pending_req_timeout_count;
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|     int revision_id = android_net_res_stats_get_info_for_net(
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|             netId, &nscount, res_servers, &dcount, res_domains, params, res_stats,
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|             &res_wait_for_pending_req_timeout_count);
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| 
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|     // If the netId is unknown (which can happen for valid net IDs for which no DNS servers have
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|     // yet been configured), there is no revision ID. In this case there is no data to return.
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|     if (revision_id < 0) {
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|         return 0;
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|     }
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| 
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|     // Verify that the returned data is valid.
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|     if (nscount < 0 || nscount > MAXNS || dcount < 0 || dcount > MAXDNSRCH) {
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|         LOG(ERROR) << __func__ << ": nscount = " << nscount << ", dcount = " << dcount;
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|         return -ENOTRECOVERABLE;
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|     }
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| 
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|     // Determine which servers are considered usable by the resolver.
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|     bool valid_servers[MAXNS];
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|     std::fill_n(valid_servers, MAXNS, false);
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|     android_net_res_stats_get_usable_servers(params, res_stats, nscount, valid_servers);
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| 
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|     // Convert the server sockaddr structures to std::string.
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|     stats->resize(nscount);
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|     for (int i = 0; i < nscount; ++i) {
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|         char hbuf[NI_MAXHOST];
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|         int rv =
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|                 getnameinfo(reinterpret_cast<const sockaddr*>(&res_servers[i]),
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|                             sizeof(res_servers[i]), hbuf, sizeof(hbuf), nullptr, 0, NI_NUMERICHOST);
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|         std::string server_str;
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|         if (rv == 0) {
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|             server_str.assign(hbuf);
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|         } else {
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|             LOG(ERROR) << "getnameinfo() failed for server #" << i << ": " << gai_strerror(rv);
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|             server_str.assign("<invalid>");
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|         }
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|         servers->push_back(std::move(server_str));
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|         android::net::ResolverStats& cur_stats = (*stats)[i];
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|         android_net_res_stats_aggregate(&res_stats[i], &cur_stats.successes, &cur_stats.errors,
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|                                         &cur_stats.timeouts, &cur_stats.internal_errors,
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|                                         &cur_stats.rtt_avg, &cur_stats.last_sample_time);
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|         cur_stats.usable = valid_servers[i];
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|     }
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| 
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|     // Convert the stack-allocated search domain strings to std::string.
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|     for (int i = 0; i < dcount; ++i) {
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|         domains->push_back(res_domains[i]);
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|     }
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| 
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|     (*wait_for_pending_req_timeout_count)[0] = res_wait_for_pending_req_timeout_count;
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|     return 0;
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| }
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| 
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| }  // namespace
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| 
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| ResolverController::ResolverController()
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|     : mDns64Configuration(
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|               [](uint32_t netId, uint32_t uid, android_net_context* netcontext) {
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|                   gResNetdCallbacks.get_network_context(netId, uid, netcontext);
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|               },
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|               std::bind(sendNat64PrefixEvent, std::placeholders::_1)) {}
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| 
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| void ResolverController::destroyNetworkCache(unsigned netId) {
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|     LOG(VERBOSE) << __func__ << ": netId = " << netId;
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| 
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|     resolv_delete_cache_for_net(netId);
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|     mDns64Configuration.stopPrefixDiscovery(netId);
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|     PrivateDnsConfiguration::getInstance().clear(netId);
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|     if (isDoHEnabled()) PrivateDnsConfiguration::getInstance().clearDoh(netId);
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| 
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|     // Don't get this instance in PrivateDnsConfiguration. It's probe to deadlock.
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|     DnsTlsDispatcher::getInstance().forceCleanup(netId);
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| }
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| 
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| int ResolverController::createNetworkCache(unsigned netId) {
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|     LOG(VERBOSE) << __func__ << ": netId = " << netId;
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| 
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|     return resolv_create_cache_for_net(netId);
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| }
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| 
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| int ResolverController::flushNetworkCache(unsigned netId) {
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|     LOG(VERBOSE) << __func__ << ": netId = " << netId;
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|     return resolv_flush_cache_for_net(netId);
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| }
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| 
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| int ResolverController::setResolverConfiguration(const ResolverParamsParcel& resolverParams) {
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|     using aidl::android::net::IDnsResolver;
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| 
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|     if (!has_named_cache(resolverParams.netId)) {
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|         return -ENOENT;
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|     }
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| 
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|     // Expect to get the mark with system permission.
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|     android_net_context netcontext;
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|     gResNetdCallbacks.get_network_context(resolverParams.netId, 0 /* uid */, &netcontext);
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| 
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|     // Allow at most MAXNS private DNS servers in a network to prevent too many broken servers.
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|     std::vector<std::string> tlsServers = resolverParams.tlsServers;
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|     if (tlsServers.size() > MAXNS) {
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|         tlsServers.resize(MAXNS);
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|     }
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| 
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|     // Use app_mark for DoT connection. Using dns_mark might result in reaching the DoT servers
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|     // through a different network. For example, on a VPN with no DNS servers (Do53), if the VPN
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|     // applies to UID 0, dns_mark is assigned for default network rathan the VPN. (note that it's
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|     // possible that a VPN doesn't have any DNS servers but DoT servers in DNS strict mode)
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|     auto& privateDnsConfiguration = PrivateDnsConfiguration::getInstance();
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|     int err = privateDnsConfiguration.set(resolverParams.netId, netcontext.app_mark, tlsServers,
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|                                           resolverParams.tlsName, resolverParams.caCertificate);
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| 
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|     if (err != 0) {
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|         return err;
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|     }
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| 
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|     if (err = resolv_stats_set_addrs(resolverParams.netId, PROTO_DOT, tlsServers, 853);
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|         err != 0) {
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|         return err;
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|     }
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| 
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|     if (is_mdns_supported_transport_types(resolverParams.transportTypes)) {
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|         if (err = resolv_stats_set_addrs(resolverParams.netId, PROTO_MDNS,
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|                                          {"ff02::fb", "224.0.0.251"}, 5353);
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|             err != 0) {
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|             return err;
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|         }
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|     }
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| 
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|     if (isDoHEnabled()) {
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|         err = privateDnsConfiguration.setDoh(resolverParams.netId, netcontext.app_mark, tlsServers,
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|                                              resolverParams.tlsName, resolverParams.caCertificate);
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| 
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|         if (err != 0) {
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|             return err;
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|         }
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|     }
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| 
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|     res_params res_params = {};
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|     res_params.sample_validity = resolverParams.sampleValiditySeconds;
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|     res_params.success_threshold = resolverParams.successThreshold;
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|     res_params.min_samples = resolverParams.minSamples;
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|     res_params.max_samples = resolverParams.maxSamples;
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|     res_params.base_timeout_msec = resolverParams.baseTimeoutMsec;
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|     res_params.retry_count = resolverParams.retryCount;
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| 
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|     return resolv_set_nameservers(resolverParams.netId, resolverParams.servers,
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|                                   resolverParams.domains, res_params,
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|                                   resolverParams.resolverOptions, resolverParams.transportTypes);
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| }
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| 
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| int ResolverController::getResolverInfo(int32_t netId, std::vector<std::string>* servers,
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|                                         std::vector<std::string>* domains,
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|                                         std::vector<std::string>* tlsServers,
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|                                         std::vector<int32_t>* params, std::vector<int32_t>* stats,
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|                                         std::vector<int32_t>* wait_for_pending_req_timeout_count) {
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|     using aidl::android::net::IDnsResolver;
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|     using android::net::ResolverStats;
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|     res_params res_params;
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|     std::vector<ResolverStats> res_stats;
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|     int ret = getDnsInfo(netId, servers, domains, &res_params, &res_stats,
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|                          wait_for_pending_req_timeout_count);
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|     if (ret != 0) {
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|         return ret;
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|     }
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| 
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|     // Serialize the information for binder.
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|     ResolverStats::encodeAll(res_stats, stats);
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| 
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|     const auto privateDnsStatus = PrivateDnsConfiguration::getInstance().getStatus(netId);
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|     for (const auto& [server, _] : privateDnsStatus.dotServersMap) {
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|         tlsServers->push_back(server.toIpString());
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|     }
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| 
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|     params->resize(IDnsResolver::RESOLVER_PARAMS_COUNT);
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|     (*params)[IDnsResolver::RESOLVER_PARAMS_SAMPLE_VALIDITY] = res_params.sample_validity;
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|     (*params)[IDnsResolver::RESOLVER_PARAMS_SUCCESS_THRESHOLD] = res_params.success_threshold;
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|     (*params)[IDnsResolver::RESOLVER_PARAMS_MIN_SAMPLES] = res_params.min_samples;
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|     (*params)[IDnsResolver::RESOLVER_PARAMS_MAX_SAMPLES] = res_params.max_samples;
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|     (*params)[IDnsResolver::RESOLVER_PARAMS_BASE_TIMEOUT_MSEC] = res_params.base_timeout_msec;
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|     (*params)[IDnsResolver::RESOLVER_PARAMS_RETRY_COUNT] = res_params.retry_count;
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|     return 0;
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| }
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| 
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| void ResolverController::startPrefix64Discovery(int32_t netId) {
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|     mDns64Configuration.startPrefixDiscovery(netId);
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| }
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| 
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| void ResolverController::stopPrefix64Discovery(int32_t netId) {
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|     return mDns64Configuration.stopPrefixDiscovery(netId);
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| }
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| 
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| // TODO: use StatusOr<T> to wrap the result.
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| int ResolverController::getPrefix64(unsigned netId, netdutils::IPPrefix* prefix) {
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|     netdutils::IPPrefix p = mDns64Configuration.getPrefix64(netId);
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|     if (p.family() != AF_INET6 || p.length() == 0) {
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|         return -ENOENT;
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|     }
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|     *prefix = p;
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|     return 0;
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| }
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| 
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| void ResolverController::dump(DumpWriter& dw, unsigned netId) {
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|     // No lock needed since Bionic's resolver locks all accessed data structures internally.
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|     using android::net::ResolverStats;
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|     std::vector<std::string> servers;
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|     std::vector<std::string> domains;
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|     res_params params = {};
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|     std::vector<ResolverStats> stats;
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|     std::vector<int32_t> wait_for_pending_req_timeout_count(1, 0);
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|     time_t now = time(nullptr);
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|     int rv = getDnsInfo(netId, &servers, &domains, ¶ms, &stats,
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|                         &wait_for_pending_req_timeout_count);
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|     dw.incIndent();
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|     if (rv != 0) {
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|         dw.println("getDnsInfo() failed for netid %u", netId);
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|     } else {
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|         if (servers.empty()) {
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|             dw.println("No DNS servers defined");
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|         } else {
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|             dw.println("DnsEvent subsampling map: " +
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|                        android::base::Join(resolv_cache_dump_subsampling_map(netId, false), ' '));
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|             dw.println("DnsEvent subsampling map for MDNS: " +
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|                        android::base::Join(resolv_cache_dump_subsampling_map(netId, true), ' '));
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|             dw.println(
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|                     "DNS servers: # IP (total, successes, errors, timeouts, internal errors, "
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|                     "RTT avg, last sample)");
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|             dw.incIndent();
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|             for (size_t i = 0; i < servers.size(); ++i) {
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|                 if (i < stats.size()) {
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|                     const ResolverStats& s = stats[i];
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|                     int total = s.successes + s.errors + s.timeouts + s.internal_errors;
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|                     if (total > 0) {
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|                         int time_delta = (s.last_sample_time > 0) ? now - s.last_sample_time : -1;
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|                         dw.println("%s (%d, %d, %d, %d, %d, %dms, %ds)%s", servers[i].c_str(),
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|                                    total, s.successes, s.errors, s.timeouts, s.internal_errors,
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|                                    s.rtt_avg, time_delta, s.usable ? "" : " BROKEN");
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|                     } else {
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|                         dw.println("%s <no data>", servers[i].c_str());
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|                     }
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|                 } else {
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|                     dw.println("%s <no stats>", servers[i].c_str());
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|                 }
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|             }
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|             dw.decIndent();
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|         }
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|         if (domains.empty()) {
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|             dw.println("No search domains defined");
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|         } else {
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|             std::string domains_str = android::base::Join(domains, ", ");
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|             dw.println("search domains: %s", domains_str.c_str());
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|         }
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|         if (params.sample_validity != 0) {
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|             dw.println(
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|                     "DNS parameters: sample validity = %us, success threshold = %u%%, "
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|                     "samples (min, max) = (%u, %u), base_timeout = %dmsec, retry count = "
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|                     "%dtimes",
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|                     params.sample_validity, params.success_threshold, params.min_samples,
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|                     params.max_samples, params.base_timeout_msec, params.retry_count);
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|         }
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| 
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|         mDns64Configuration.dump(dw, netId);
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|         const auto privateDnsStatus = PrivateDnsConfiguration::getInstance().getStatus(netId);
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|         dw.println("Private DNS mode: %s", getPrivateDnsModeString(privateDnsStatus.mode));
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|         if (privateDnsStatus.dotServersMap.size() == 0) {
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|             dw.println("No Private DNS servers configured");
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|         } else {
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|             dw.println("Private DNS configuration (%u entries)",
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|                        static_cast<uint32_t>(privateDnsStatus.dotServersMap.size()));
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|             dw.incIndent();
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|             for (const auto& [server, validation] : privateDnsStatus.dotServersMap) {
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|                 dw.println("%s name{%s} status{%s}", server.toIpString().c_str(),
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|                            server.name.c_str(), validationStatusToString(validation));
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|             }
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|             dw.decIndent();
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|         }
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|         dw.println("Concurrent DNS query timeout: %d", wait_for_pending_req_timeout_count[0]);
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|         resolv_netconfig_dump(dw, netId);
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|     }
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|     dw.decIndent();
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| }
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| 
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| }  // namespace net
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| }  // namespace android
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