// Copyright (c) 2012 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "net/dns/host_resolver.h" #include "base/logging.h" #include "base/metrics/field_trial.h" #include "base/strings/string_number_conversions.h" #include "base/strings/string_split.h" #include "base/values.h" #include "net/base/net_errors.h" #include "net/dns/dns_client.h" #include "net/dns/dns_config_service.h" #include "net/dns/host_cache.h" #include "net/dns/host_resolver_impl.h" namespace net { namespace { // Maximum of 6 concurrent resolver threads (excluding retries). // Some routers (or resolvers) appear to start to provide host-not-found if // too many simultaneous resolutions are pending. This number needs to be // further optimized, but 8 is what FF currently does. We found some routers // that limit this to 6, so we're temporarily holding it at that level. const size_t kDefaultMaxProcTasks = 6u; } // namespace PrioritizedDispatcher::Limits HostResolver::Options::GetDispatcherLimits() const { PrioritizedDispatcher::Limits limits(NUM_PRIORITIES, max_concurrent_resolves); // If not using default, do not use the field trial. if (limits.total_jobs != HostResolver::kDefaultParallelism) return limits; // Default, without trial is no reserved slots. limits.total_jobs = kDefaultMaxProcTasks; // Parallelism is determined by the field trial. std::string group = base::FieldTrialList::FindFullName( "HostResolverDispatch"); if (group.empty()) return limits; // The format of the group name is a list of non-negative integers separated // by ':'. Each of the elements in the list corresponds to an element in // |reserved_slots|, except the last one which is the |total_jobs|. std::vector group_parts = base::SplitStringPiece( group, ":", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL); if (group_parts.size() != NUM_PRIORITIES + 1) { NOTREACHED(); return limits; } std::vector parsed(group_parts.size()); size_t total_reserved_slots = 0; for (size_t i = 0; i < group_parts.size(); ++i) { if (!base::StringToSizeT(group_parts[i], &parsed[i])) { NOTREACHED(); return limits; } } size_t total_jobs = parsed.back(); parsed.pop_back(); for (size_t i = 0; i < parsed.size(); ++i) { total_reserved_slots += parsed[i]; } // There must be some unreserved slots available for the all priorities. if (total_reserved_slots > total_jobs || (total_reserved_slots == total_jobs && parsed[MINIMUM_PRIORITY] == 0)) { NOTREACHED(); return limits; } limits.total_jobs = total_jobs; limits.reserved_slots = parsed; return limits; } HostResolver::Options::Options() : max_concurrent_resolves(kDefaultParallelism), max_retry_attempts(kDefaultRetryAttempts), enable_caching(true) { } HostResolver::RequestInfo::RequestInfo(const HostPortPair& host_port_pair) : RequestInfo() { host_port_pair_ = host_port_pair; } HostResolver::RequestInfo::RequestInfo(const RequestInfo& request_info) = default; HostResolver::RequestInfo::~RequestInfo() = default; HostResolver::RequestInfo::RequestInfo() : address_family_(ADDRESS_FAMILY_UNSPECIFIED), host_resolver_flags_(0), allow_cached_response_(true), is_speculative_(false), is_my_ip_address_(false) {} HostResolver::~HostResolver() = default; void HostResolver::SetDnsClientEnabled(bool enabled) { } HostCache* HostResolver::GetHostCache() { return nullptr; } std::unique_ptr HostResolver::GetDnsConfigAsValue() const { return nullptr; } void HostResolver::InitializePersistence( const PersistCallback& persist_callback, std::unique_ptr old_data) {} void HostResolver::SetNoIPv6OnWifi(bool no_ipv6_on_wifi) { NOTREACHED(); } bool HostResolver::GetNoIPv6OnWifi() { return false; } // static std::unique_ptr HostResolver::CreateSystemResolver( const Options& options, NetLog* net_log) { return std::unique_ptr( CreateSystemResolverImpl(options, net_log).release()); } // static std::unique_ptr HostResolver::CreateSystemResolverImpl( const Options& options, NetLog* net_log) { return std::make_unique(options, net_log); } // static std::unique_ptr HostResolver::CreateDefaultResolver( NetLog* net_log) { return CreateSystemResolver(Options(), net_log); } // static std::unique_ptr HostResolver::CreateDefaultResolverImpl( NetLog* net_log) { return CreateSystemResolverImpl(Options(), net_log); } HostResolver::HostResolver() = default; } // namespace net