blob: 501d0fc4b4c528c8377740ab63db36491aadb17c [file] [log] [blame]
// Copyright (c) 2011 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 <list>
#include <map>
#include "base/memory/weak_ptr.h"
#include "base/synchronization/waitable_event.h"
#include "base/threading/non_thread_safe.h"
#include "net/dns/host_resolver.h"
#include "net/dns/host_resolver_proc.h"
namespace net {
class HostCache;
class RuleBasedHostResolverProc;
// Fills |*addrlist| with a socket address for |host_list| which should be a
// comma-separated list of IPv4 or IPv6 literal(s) without enclosing brackets.
// If |canonical_name| is non-empty it is used as the DNS canonical name for
// the host. Returns OK on success, ERR_UNEXPECTED otherwise.
int ParseAddressList(const std::string& host_list,
const std::string& canonical_name,
AddressList* addrlist);
// In most cases, it is important that unit tests avoid relying on making actual
// DNS queries since the resulting tests can be flaky, especially if the network
// is unreliable for some reason. To simplify writing tests that avoid making
// actual DNS queries, pass a MockHostResolver as the HostResolver dependency.
// The socket addresses returned can be configured using the
// RuleBasedHostResolverProc:
// host_resolver->rules()->AddRule("", "");
// host_resolver->rules()->AddRule("", "");
// The above rules define a static mapping from hostnames to IP address
// literals. The first parameter to AddRule specifies a host pattern to match
// against, and the second parameter indicates what value should be used to
// replace the given hostname. So, the following is also supported:
// host_mapper->AddRule("*.com", "");
// Replacement doesn't have to be string representing an IP address. It can
// re-map one hostname to another as well.
// By default, MockHostResolvers include a single rule that maps all hosts to
// Base class shared by MockHostResolver and MockCachingHostResolver.
class MockHostResolverBase : public HostResolver,
public base::SupportsWeakPtr<MockHostResolverBase>,
public base::NonThreadSafe {
~MockHostResolverBase() override;
RuleBasedHostResolverProc* rules() { return rules_.get(); }
void set_rules(RuleBasedHostResolverProc* rules) { rules_ = rules; }
// Controls whether resolutions complete synchronously or asynchronously.
void set_synchronous_mode(bool is_synchronous) {
synchronous_mode_ = is_synchronous;
// Asynchronous requests are automatically resolved by default.
// If set_ondemand_mode() is set then Resolve() returns IO_PENDING and
// ResolveAllPending() must be explicitly invoked to resolve all requests
// that are pending.
void set_ondemand_mode(bool is_ondemand) {
ondemand_mode_ = is_ondemand;
// HostResolver methods:
int Resolve(const RequestInfo& info,
RequestPriority priority,
AddressList* addresses,
const CompletionCallback& callback,
RequestHandle* out_req,
const BoundNetLog& net_log) override;
int ResolveFromCache(const RequestInfo& info,
AddressList* addresses,
const BoundNetLog& net_log) override;
void CancelRequest(RequestHandle req) override;
HostCache* GetHostCache() override;
// Resolves all pending requests. It is only valid to invoke this if
// set_ondemand_mode was set before. The requests are resolved asynchronously,
// after this call returns.
void ResolveAllPending();
// Returns true if there are pending requests that can be resolved by invoking
// ResolveAllPending().
bool has_pending_requests() const { return !requests_.empty(); }
// The number of times that Resolve() has been called.
size_t num_resolve() const {
return num_resolve_;
// The number of times that ResolveFromCache() has been called.
size_t num_resolve_from_cache() const {
return num_resolve_from_cache_;
// Returns the RequestPriority of the last call to Resolve() (or
// DEFAULT_PRIORITY if Resolve() hasn't been called yet).
RequestPriority last_request_priority() const {
return last_request_priority_;
explicit MockHostResolverBase(bool use_caching);
struct Request;
typedef std::map<size_t, Request*> RequestMap;
// Resolve as IP or from |cache_| return cached error or
// DNS_CACHE_MISS if failed.
int ResolveFromIPLiteralOrCache(const RequestInfo& info,
AddressList* addresses);
// Resolve via |proc_|.
int ResolveProc(size_t id, const RequestInfo& info, AddressList* addresses);
// Resolve request stored in |requests_|. Pass rv to callback.
void ResolveNow(size_t id);
RequestPriority last_request_priority_;
bool synchronous_mode_;
bool ondemand_mode_;
scoped_refptr<RuleBasedHostResolverProc> rules_;
scoped_ptr<HostCache> cache_;
RequestMap requests_;
size_t next_request_id_;
size_t num_resolve_;
size_t num_resolve_from_cache_;
class MockHostResolver : public MockHostResolverBase {
MockHostResolver() : MockHostResolverBase(false /*use_caching*/) {}
~MockHostResolver() override {}
// Same as MockHostResolver, except internally it uses a host-cache.
// Note that tests are advised to use MockHostResolver instead, since it is
// more predictable. (MockHostResolver also can be put into synchronous
// operation mode in case that is what you needed from the caching version).
class MockCachingHostResolver : public MockHostResolverBase {
MockCachingHostResolver() : MockHostResolverBase(true /*use_caching*/) {}
~MockCachingHostResolver() override {}
// RuleBasedHostResolverProc applies a set of rules to map a host string to
// a replacement host string. It then uses the system host resolver to return
// a socket address. Generally the replacement should be an IPv4 literal so
// there is no network dependency.
class RuleBasedHostResolverProc : public HostResolverProc {
explicit RuleBasedHostResolverProc(HostResolverProc* previous);
// Any hostname matching the given pattern will be replaced with the given
// replacement value. Usually, replacement should be an IP address literal.
void AddRule(const std::string& host_pattern,
const std::string& replacement);
// Same as AddRule(), but further restricts to |address_family|.
void AddRuleForAddressFamily(const std::string& host_pattern,
AddressFamily address_family,
const std::string& replacement);
// Same as AddRule(), but the replacement is expected to be an IPv4 or IPv6
// literal. This can be used in place of AddRule() to bypass the system's
// host resolver (the address list will be constructed manually).
// If |canonical_name| is non-empty, it is copied to the resulting AddressList
// but does not impact DNS resolution.
// |ip_literal| can be a single IP address like "" or a comma
// separated list of IP addresses, like "::1,192:168.1.2".
void AddIPLiteralRule(const std::string& host_pattern,
const std::string& ip_literal,
const std::string& canonical_name);
void AddRuleWithLatency(const std::string& host_pattern,
const std::string& replacement,
int latency_ms);
// Make sure that |host| will not be re-mapped or even processed by underlying
// host resolver procedures. It can also be a pattern.
void AllowDirectLookup(const std::string& host);
// Simulate a lookup failure for |host| (it also can be a pattern).
void AddSimulatedFailure(const std::string& host);
// Deletes all the rules that have been added.
void ClearRules();
// HostResolverProc methods:
int Resolve(const std::string& host,
AddressFamily address_family,
HostResolverFlags host_resolver_flags,
AddressList* addrlist,
int* os_error) override;
struct Rule;
typedef std::list<Rule> RuleList;
~RuleBasedHostResolverProc() override;
RuleList rules_;
// Create rules that map all requests to localhost.
RuleBasedHostResolverProc* CreateCatchAllHostResolverProc();
// HangingHostResolver never completes its |Resolve| request.
class HangingHostResolver : public HostResolver {
int Resolve(const RequestInfo& info,
RequestPriority priority,
AddressList* addresses,
const CompletionCallback& callback,
RequestHandle* out_req,
const BoundNetLog& net_log) override;
int ResolveFromCache(const RequestInfo& info,
AddressList* addresses,
const BoundNetLog& net_log) override;
void CancelRequest(RequestHandle req) override {}
// This class sets the default HostResolverProc for a particular scope. The
// chain of resolver procs starting at |proc| is placed in front of any existing
// default resolver proc(s). This means that if multiple
// ScopedDefaultHostResolverProcs are declared, then resolving will start with
// the procs given to the last-allocated one, then fall back to the procs given
// to the previously-allocated one, and so forth.
// NOTE: Only use this as a catch-all safety net. Individual tests should use
// MockHostResolver.
class ScopedDefaultHostResolverProc {
explicit ScopedDefaultHostResolverProc(HostResolverProc* proc);
void Init(HostResolverProc* proc);
scoped_refptr<HostResolverProc> current_proc_;
scoped_refptr<HostResolverProc> previous_proc_;
} // namespace net