Abstract base for protocol-specific in-process mock servers. More...

#include <mock_server_base.h>

Inheritance diagram for proto_fuzzer::MockServerBase:

Public Types
using	MultiObserver = std::function<void(CURLM*)>
	Callback type used to publish the driving multi handle to observers.

Public Member Functions
virtual	~MockServerBase ()
	Out-of-line destructor so MockConnection can stay forward-declared in the base header (its complete type is only needed where unique_ptr is instantiated for destruction).
virtual void	ObserveState ()
	Default no-op for peers without protocol-specific observations.
virtual void	Install (CURL *easy)
	Install the common OPENSOCKETFUNCTION / OPENSOCKETDATA / SOCKOPTFUNCTION callbacks on 'easy'.
virtual void	ConfigureRequestData (ScenarioRequestData *request_data)
	Bind protocol-specific work to the request-data callbacks after their per-scenario state has been constructed.
CURLcode	DriveScenario (CURL *easy, const curl::fuzzer::proto::Scenario &scenario)
	Run 'scenario' to completion on 'easy': allocate a multi, attach 'easy', delegate protocol-specific work to RunLoop, consume its completion message, and clean up.
virtual CURLcode	DriveEasyScenario (CURL *easy, const curl::fuzzer::proto::Scenario &scenario, bool use_events=false)
	Run through the public easy entrypoint when a protocol mock can preload all peer work before curl takes control.
virtual ConnectOnlyRunStats	DriveConnectOnlyScenario (CURL *easy, const curl::fuzzer::proto::Scenario &scenario)
	Establish a CONNECT_ONLY transport, then perform bounded direct I/O.
void	SetMultiObserver (MultiObserver observer)
	Register an observer invoked with the live multi handle after 'easy' is attached and before the drive loop starts.
MockConnection *	connection ()

Protected Member Functions
	MockServerBase (MultiDrivePolicy drive_policy=MultiDrivePolicy::kPerform)
	Construct an empty base instance with a fixed multi-drive policy.
virtual void	HandleDetachedMulti (CurlMultiPtr multi)
	Dispose of or retain the multi after its easy handle has been removed.
virtual curl_socket_t	HandleOpenSocket (curlsocktype purpose, struct curl_sockaddr *address)=0
	Subclass hook invoked by the OPENSOCKET trampoline.
virtual SocketSetupDisposition	GetSocketSetupDisposition (curl_socket_t curlfd, curlsocktype purpose) const
	Describe the socket returned by HandleOpenSocket without issuing native descriptor queries.
virtual void	RunLoop (CURLM multi, CURL easy, const curl::fuzzer::proto::Scenario &scenario)=0
	Subclass hook invoked from DriveScenario.
MultiSocketDriver *	multi_socket_driver ()
	Expose the callback state installed for the current socket-action drive.
std::size_t	additional_handle_cleanup_count () const
void	ResumeResponseIfRequested (CURL *easy)
	Resume receive-side callback output at one bounded drive boundary when the dedicated API plan requested it.
void	ApplyPendingBackpressure ()
	Apply the BackpressureConfig cached by DriveScenario to the new connection_.

Static Protected Member Functions
static int	WaitOnMultiFdset (CURLM multi, CURLMcode rc)
	Wait on curl's fdset with a short timeout.
static void	ProbeMultiPollset (CURLM *multi)
	Ask curl to construct and inspect its connection-filter pollset without waiting.
static bool	MultiPollsetWantsWrite (CURLM *multi, curl_socket_t socket)
	Inspect one socket's current writable interest through curl's public multi fdset API.
static bool	UsesTimedDrive (const curl::fuzzer::proto::Scenario &scenario)
	Treat a non-default BackpressureConfig as an explicit request for the slower, timed drive policy.

Protected Attributes
std::unique_ptr< MockConnection >	connection_
	The per-scenario MockConnection, lazily created by HandleOpenSocket().
int	pending_recv_buf_bytes_
	Cached SO_RCVBUF/SO_SNDBUF setting in bytes.
std::size_t	pending_drain_limit_
	Cached per-call DrainIncoming byte budget.
MultiSocketDriver *	multi_socket_driver_
	Non-owning pointer into DriveScenario's stack.
std::size_t	additional_handle_cleanup_count_
	Number of application-created handles, excluding the caller's parent, successfully removed from the current multi and cleaned up.
bool	resume_response_
	True only for an API-plan multi drive with its one-shot write callback.
MultiObserver	multi_observer_
	Observer receiving the live multi handle at the start of a drive.

Static Protected Attributes
static constexpr int	kMaxDriveIterations = 512
	Hard operation budget for one scenario.
static constexpr int	kMaxIdleIterations = 8
	Consecutive no-progress budget for ordinary scenarios.
static constexpr int	kMaxTimedIdleIterations = 256
	Explicit backpressure scenarios get a larger idle budget and may use the short timed wait above.

Friends
curl_socket_t	MockServerBaseOpenSocketTrampoline (void clientp, curlsocktype purpose, struct curl_sockaddr address)
	C trampoline for CURLOPT_OPENSOCKETFUNCTION.
int	MockServerBaseSockOptTrampoline (void *clientp, curl_socket_t curlfd, curlsocktype purpose)
	Translate explicit peer transport metadata into curl's sockopt callback contract.

Detailed Description

Abstract base for protocol-specific in-process mock servers.

Owns a single MockConnection (the socketpair curl talks to) and dispatches the OPENSOCKET callback through a virtual HandleOpenSocket so the subclass can decide whether to write anything immediately. Each subclass overrides RunLoop to seed itself from the Scenario proto and run its own perform loop; the base's DriveScenario owns the curl_multi handle around that call.

Definition at line 67 of file mock_server_base.h.

Constructor & Destructor Documentation

◆ MockServerBase()

proto_fuzzer::MockServerBase::MockServerBase ( MultiDrivePolicy drive_policy = MultiDrivePolicy::kPerform )

explicitprotected

Construct an empty base instance with a fixed multi-drive policy.

Parameters

drive_policy Whether to perform, use socket actions, or honor the containing Scenario's ApiPlan.

Definition at line 69 of file mock_server_base.cc.

Member Function Documentation

◆ additional_handle_cleanup_count()

std::size_t proto_fuzzer::MockServerBase::additional_handle_cleanup_count ( ) const

protected

Returns: extra easy handles removed and cleaned after the latest drive. Server push is currently the only path that can add one behind the caller's back; exposing the count to subclasses keeps ownership in this multi-owning base while allowing focused lifecycle assertions.

Definition at line 278 of file mock_server_base.cc.

◆ ApplyPendingBackpressure()

void proto_fuzzer::MockServerBase::ApplyPendingBackpressure ( )

protected

Apply the BackpressureConfig cached by DriveScenario to the new connection_.

Subclasses call this at the end of HandleOpenSocket, before returning the client fd, so SO_RCVBUF takes effect before traffic flows. Safe to call when connection_ is null or both knobs are zero: those cases are no-ops.

Definition at line 296 of file mock_server_base.cc.

◆ ConfigureRequestData()

void proto_fuzzer::MockServerBase::ConfigureRequestData ( ScenarioRequestData * request_data )

virtual

Bind protocol-specific work to the request-data callbacks after their per-scenario state has been constructed.

Ordinary HTTP and WebSocket mocks regain control in their outer perform loops and drain client traffic there. Most mocks therefore need no hook; TELNET uses this upload-callback boundary to drain client replies while curl owns the thread.

Parameters

request_data Callback state that outlives the subsequent drive.

Reimplemented in proto_fuzzer::DohHttpsRrMockServer, proto_fuzzer::HappyEyeballsMockServer, and proto_fuzzer::TelnetMockServer.

Definition at line 125 of file mock_server_base.cc.

◆ connection()

MockConnection * proto_fuzzer::MockServerBase::connection ( )

Returns: the owned MockConnection, or nullptr if one has not been opened.

Definition at line 89 of file mock_server_base.cc.

◆ DriveConnectOnlyScenario()

ConnectOnlyRunStats proto_fuzzer::MockServerBase::DriveConnectOnlyScenario	(	CURL *	easy,
		const curl::fuzzer::proto::Scenario &	scenario )

virtual

Establish a CONNECT_ONLY transport, then perform bounded direct I/O.

HTTP overrides this; other protocol mocks retain a safe fallback.

Parameters

easy	curl easy handle already Install()ed on this mock.
scenario	Scenario supplying response and direct-I/O bytes.

Returns: Results and byte counts from connect, send, and receive probes.

Reimplemented in proto_fuzzer::MockServer.

Definition at line 259 of file mock_server_base.cc.

◆ DriveEasyScenario()

CURLcode proto_fuzzer::MockServerBase::DriveEasyScenario	(	CURL *	easy,
		const curl::fuzzer::proto::Scenario &	scenario,
		bool	use_events = false )

virtual

Run through the public easy entrypoint when a protocol mock can preload all peer work before curl takes control.

The base preserves the ordinary multi-drive fallback for protocols that require an outer driver to make progress. The API policy currently forces HTTP, whose override preloads its bounded response and calls curl_easy_perform without a thread.

Parameters

easy	curl easy handle already Install()ed on this mock.
scenario	Scenario whose response the mock must prepare.
use_events	Select curl's debug event-based easy entrypoint when the concrete mock supports it.

Returns: Transfer result reported by the selected easy or fallback drive.

Reimplemented in proto_fuzzer::MockServer.

Definition at line 249 of file mock_server_base.cc.

◆ DriveScenario()

CURLcode proto_fuzzer::MockServerBase::DriveScenario	(	CURL *	easy,
		const curl::fuzzer::proto::Scenario &	scenario )

Run 'scenario' to completion on 'easy': allocate a multi, attach 'easy', delegate protocol-specific work to RunLoop, consume its completion message, and clean up.

Read the result before removing the only easy handle so every protocol runner exercises the public multi-result path. Harness setup failures return a stable sentinel; fuzzer callers may ignore it while unit tests can assert the protocol result without adding another callback or global.

Parameters

easy	curl easy handle already Install()ed on this mock.
scenario	the Scenario proto to drive.

Returns: the completed transfer's CURLcode, or CURLE_FAILED_INIT when the bounded drive could not produce a completion message.

Definition at line 138 of file mock_server_base.cc.

◆ GetSocketSetupDisposition()

SocketSetupDisposition proto_fuzzer::MockServerBase::GetSocketSetupDisposition	(	curl_socket_t	curlfd,
		curlsocktype	purpose ) const

protectedvirtual

Describe the socket returned by HandleOpenSocket without issuing native descriptor queries.

Stream peers return connected socketpairs; accepted sockets and datagram peers require curl's ordinary setup.

Parameters

curlfd	Descriptor returned by HandleOpenSocket.
purpose	Role curl assigned to the descriptor.

Returns: Whether curl must perform its normal socket setup.

Reimplemented in proto_fuzzer::FtpMockServer, proto_fuzzer::HappyEyeballsMockServer, proto_fuzzer::Http3MockServer, and proto_fuzzer::TftpMockServer.

Definition at line 110 of file mock_server_base.cc.

◆ HandleDetachedMulti()

void proto_fuzzer::MockServerBase::HandleDetachedMulti ( CurlMultiPtr multi )

protectedvirtual

Dispose of or retain the multi after its easy handle has been removed.

The default destroys it before DriveScenario returns. A protocol mock may retain it as member state when its fixed lifecycle requires easy cleanup to happen first.

Parameters

multi Detached multi handle and its live connection cache.

Reimplemented in proto_fuzzer::H2CleartextMockServer, proto_fuzzer::H2OriginMockServer, and proto_fuzzer::PingpongMockServer.

Definition at line 237 of file mock_server_base.cc.

◆ HandleOpenSocket()

virtual curl_socket_t proto_fuzzer::MockServerBase::HandleOpenSocket	(	curlsocktype	purpose,
		struct curl_sockaddr *	address )

protectedpure virtual

Subclass hook invoked by the OPENSOCKET trampoline.

The subclass owns the decision to construct connection_, push any initial bytes, and hand the client fd back to libcurl. Passing curl's mutable destination through is essential for datagram protocols: TFTP must replace the nominal URL port with its per-scenario loopback request socket before curl records the address used by sendto(). Stream socketpair peers simply ignore it.

Parameters

purpose	The role curl intends the new socket to serve.
address	Mutable destination and native socket description.

Returns: the client-side fd to hand to libcurl, or CURL_SOCKET_BAD.

Implemented in proto_fuzzer::FtpMockServer, proto_fuzzer::HappyEyeballsMockServer, proto_fuzzer::Http3MockServer, proto_fuzzer::LdapMockServer, proto_fuzzer::MockServer, proto_fuzzer::MqttMockServer, proto_fuzzer::PingpongMockServer, proto_fuzzer::RtspMockServer, proto_fuzzer::TelnetMockServer, proto_fuzzer::TftpMockServer, and proto_fuzzer::WebSocketMockServer.

◆ Install()

void proto_fuzzer::MockServerBase::Install ( CURL * easy )

virtual

Install the common OPENSOCKETFUNCTION / OPENSOCKETDATA / SOCKOPTFUNCTION callbacks on 'easy'.

All subclasses share the trampolines, which route back into this instance through HandleOpenSocket. Subclasses may override to layer additional protocol-specific setopts, such as a WRITEFUNCTION that exercises protocol APIs from inside a curl callback.

Parameters

easy	The curl easy handle to configure.

Definition at line 97 of file mock_server_base.cc.

◆ multi_socket_driver()

MultiSocketDriver * proto_fuzzer::MockServerBase::multi_socket_driver ( )

protected

Expose the callback state installed for the current socket-action drive.

HTTP's RunLoop uses this instead of reading the proto directly, so only the dedicated API binary can opt into lifecycle work and compatibility inputs containing the new field retain their old behavior. Ownership remains in DriveScenario so no subclass can shorten the driver's lifetime.

Returns: active driver, or nullptr for the ordinary perform path.

Definition at line 272 of file mock_server_base.cc.

◆ MultiPollsetWantsWrite()

bool proto_fuzzer::MockServerBase::MultiPollsetWantsWrite	(	CURLM *	multi,
		curl_socket_t	socket )

staticprotected

Inspect one socket's current writable interest through curl's public multi fdset API.

MockConnection already rejects descriptors outside FD_SETSIZE, so the matching FD_ISSET operation remains bounded.

Parameters

multi	Multi handle that owns the socket.
socket	Socket returned to curl by the open-socket callback.

Returns: true when curl currently waits for the socket to become writable.

Definition at line 357 of file mock_server_base.cc.

◆ ObserveState()

void proto_fuzzer::MockServerBase::ObserveState ( )

virtual

Default no-op for peers without protocol-specific observations.

Overrides retain bounded state only in coverage and introspector builds; a derived peer calls its base implementation before observing its own state.

Definition at line 86 of file mock_server_base.cc.

◆ ProbeMultiPollset()

void proto_fuzzer::MockServerBase::ProbeMultiPollset ( CURLM * multi )

staticprotected

Ask curl to construct and inspect its connection-filter pollset without waiting.

A perform-only harness can complete local socketpair transfers while skipping the public multi-poll path used by event-driven applications. Selected opt-in scenarios make zero-timeout probes to retain that coverage without taxing the default fast path. The result is ignored: the protocol-specific perform loop determines transfer progress.

Parameters

multi The active multi handle after at least one perform call.

Definition at line 346 of file mock_server_base.cc.

◆ ResumeResponseIfRequested()

void proto_fuzzer::MockServerBase::ResumeResponseIfRequested ( CURL * easy )

protected

Resume receive-side callback output at one bounded drive boundary when the dedicated API plan requested it.

Calling CONT before the callback pauses is harmless; repeating it ensures a later response chunk cannot leave the transfer suspended until timeout.

Parameters

easy	Active easy handle whose receive callbacks may be paused.

Definition at line 285 of file mock_server_base.cc.

◆ RunLoop()

virtual void proto_fuzzer::MockServerBase::RunLoop	(	CURLM *	multi,
		CURL *	easy,
		const curl::fuzzer::proto::Scenario &	scenario )

protectedpure virtual

Subclass hook invoked from DriveScenario.

Runs the protocol-specific perform loop against a caller-owned multi that already has 'easy' added.

Parameters

multi	multi handle owned by DriveScenario; easy already added.
easy	the curl easy handle attached to the mock.
scenario	the Scenario proto to drive.

◆ SetMultiObserver()

void proto_fuzzer::MockServerBase::SetMultiObserver ( MultiObserver observer )

inline

Register an observer invoked with the live multi handle after 'easy' is attached and before the drive loop starts.

The API lifecycle lane uses it so public API probes fired from inside callbacks can target the multi that actually owns the transfer. Passing an empty observer clears it.

Parameters

observer Callback receiving the live multi handle.

Definition at line 95 of file mock_server_base.h.

◆ UsesTimedDrive()

bool proto_fuzzer::MockServerBase::UsesTimedDrive ( const curl::fuzzer::proto::Scenario & scenario )

staticprotected

Treat a non-default BackpressureConfig as an explicit request for the slower, timed drive policy.

Proto3 scalar defaults make this deterministic: a present-but-empty message remains on the ordinary fast path.

Parameters

scenario Scenario whose backpressure settings select the policy.

Returns: true when the scenario explicitly opted into socket backpressure.

Definition at line 307 of file mock_server_base.cc.

◆ WaitOnMultiFdset()

int proto_fuzzer::MockServerBase::WaitOnMultiFdset	(	CURLM *	multi,
		CURLMcode *	rc )

staticprotected

Wait on curl's fdset with a short timeout.

Drive loops call this only for scenarios that explicitly request backpressure/timing behaviour; ordinary scenarios run without wall-clock sleeps.

Parameters

multi	The multi handle whose fdset to poll.
rc	Out parameter: set to the CURLMcode on error.

Returns: select()'s result, or -1 on curl_multi_fdset failure.

Definition at line 318 of file mock_server_base.cc.

◆ MockServerBaseOpenSocketTrampoline

curl_socket_t MockServerBaseOpenSocketTrampoline	(	void *	clientp,
		curlsocktype	purpose,
		struct curl_sockaddr *	address )

friend

C trampoline for CURLOPT_OPENSOCKETFUNCTION.

Declared at namespace scope so it can be a friend of MockServerBase.

Parameters

clientp	Pointer to the MockServerBase instance.
purpose	The socket role curl is asking the mock to provide.
address	Curl's mutable description of the intended destination.

Returns: The client-side socket fd as a curl_socket_t.

Definition at line 48 of file mock_server_base.cc.

◆ MockServerBaseSockOptTrampoline

int MockServerBaseSockOptTrampoline	(	void *	clientp,
		curl_socket_t	curlfd,
		curlsocktype	purpose )

friend

Translate explicit peer transport metadata into curl's sockopt callback contract.

The descriptor is used only as an opaque identity; sandbox policy must not decide whether an otherwise valid in-process transport can run.

Parameters

clientp	Pointer to the MockServerBase instance.
curlfd	Descriptor returned by the open-socket callback.
purpose	Socket role assigned by curl.

Returns: CURL_SOCKOPT_ALREADY_CONNECTED for prepared stream peers, otherwise CURL_SOCKOPT_OK.

Definition at line 61 of file mock_server_base.cc.

Member Data Documentation

◆ connection_

std::unique_ptr<MockConnection> proto_fuzzer::MockServerBase::connection_

protected

The per-scenario MockConnection, lazily created by HandleOpenSocket().

Subclasses read/write through this pointer inside their RunLoop.

Definition at line 158 of file mock_server_base.h.

◆ kMaxDriveIterations

int proto_fuzzer::MockServerBase::kMaxDriveIterations = 512

staticconstexprprotected

Hard operation budget for one scenario.

This bounds cases that continue making tiny amounts of progress (for example a one-byte backpressure drain) without relying on wall-clock time.

Definition at line 140 of file mock_server_base.h.

◆ kMaxIdleIterations

int proto_fuzzer::MockServerBase::kMaxIdleIterations = 8

staticconstexprprotected

Consecutive no-progress budget for ordinary scenarios.

Socketpair I/O is local and should settle immediately, so a handful of extra performs is enough to flush curl's state machine without sleeping.

Definition at line 145 of file mock_server_base.h.

◆ kMaxTimedIdleIterations

int proto_fuzzer::MockServerBase::kMaxTimedIdleIterations = 256

staticconstexprprotected

Explicit backpressure scenarios get a larger idle budget and may use the short timed wait above.

This keeps timeout/error branches reachable while ensuring ordinary mutations never inherit their cost.

Definition at line 150 of file mock_server_base.h.

◆ multi_socket_driver_

MultiSocketDriver* proto_fuzzer::MockServerBase::multi_socket_driver_

protected

Non-owning pointer into DriveScenario's stack.

That scope encloses easy removal and multi cleanup, the complete interval in which callbacks may still fire.

Definition at line 171 of file mock_server_base.h.

◆ pending_drain_limit_

std::size_t proto_fuzzer::MockServerBase::pending_drain_limit_

protected

Cached per-call DrainIncoming byte budget.

Same population timing as pending_recv_buf_bytes_; 0 means unlimited (legacy drain behaviour).

Definition at line 166 of file mock_server_base.h.

◆ pending_recv_buf_bytes_

int proto_fuzzer::MockServerBase::pending_recv_buf_bytes_

protected

Cached SO_RCVBUF/SO_SNDBUF setting in bytes.

Populated by DriveScenario before the first curl_multi_perform so HandleOpenSocket can consult it when it constructs the MockConnection.

Definition at line 163 of file mock_server_base.h.

The documentation for this class was generated from the following files:

proto_fuzzer/mock_server_base.h
proto_fuzzer/mock_server_base.cc

Public Types

Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Static Protected Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ MockServerBase()

Member Function Documentation

◆ additional_handle_cleanup_count()

◆ ApplyPendingBackpressure()

◆ ConfigureRequestData()

◆ connection()

◆ DriveConnectOnlyScenario()

◆ DriveEasyScenario()

◆ DriveScenario()

◆ GetSocketSetupDisposition()

◆ HandleDetachedMulti()

◆ HandleOpenSocket()

◆ Install()

◆ multi_socket_driver()

◆ MultiPollsetWantsWrite()

◆ ObserveState()

◆ ProbeMultiPollset()

◆ ResumeResponseIfRequested()

◆ RunLoop()

◆ SetMultiObserver()

◆ UsesTimedDrive()

◆ WaitOnMultiFdset()

Friends And Related Symbol Documentation

◆ MockServerBaseOpenSocketTrampoline

◆ MockServerBaseSockOptTrampoline

Member Data Documentation

◆ connection_

◆ kMaxDriveIterations

◆ kMaxIdleIterations

◆ kMaxTimedIdleIterations

◆ multi_socket_driver_

◆ pending_drain_limit_

◆ pending_recv_buf_bytes_