Services curl's single-connection binary MQTT exchange. More...

#include <mqtt_mock_server.h>

Inheritance diagram for proto_fuzzer::MqttMockServer:

Public Member Functions
	MqttMockServer (curl::fuzzer::proto::MqttProbeMode mode=curl::fuzzer::proto::MQTT_PROBE_DEFAULT)
	Begin without a borrowed protobuf or open socketpair.
	~MqttMockServer () override
	Release the server-owned socketpair half after curl has returned its client descriptor.
void	ObserveState () override
	Retain protocol outcomes in coverage and introspector builds.
const std::string &	packet_transcript () const
const std::string &	published_topic () const
const std::string &	published_payload () const
std::size_t	packet_count () const
std::size_t	connect_count () const
std::size_t	publish_count () const
std::size_t	subscribe_count () const
std::size_t	qos1_publish_count () const
std::size_t	active_pollset_probe_count () const
	Report how many requested zero-timeout multi-poll probes ran during the most recent drive.
Public Member Functions inherited from proto_fuzzer::MockServerBase
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	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
virtual std::unique_ptr< MockConnection >	CreateConnection ()
	Create the default plaintext transport for the MQTT packet exchange.
curl_socket_t	HandleOpenSocket (curlsocktype purpose=CURLSOCKTYPE_IPCXN, struct curl_sockaddr *address=nullptr) override
	Create the single MQTT socketpair and queue the scenario's first server bytes.
void	RunLoop (CURLM multi, CURL easy, const curl::fuzzer::proto::Scenario &scenario) override
	Alternate curl transitions with immediate peer service until the transfer completes or deterministic idle/operation caps win.
void	ObserveIncomingData (const unsigned char *data, std::size_t size) override
	Append decoded application bytes to the pending parser buffer.
Protected Member Functions inherited from proto_fuzzer::MockServerBase
	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 SocketSetupDisposition	GetSocketSetupDisposition (curl_socket_t curlfd, curlsocktype purpose) const
	Describe the socket returned by HandleOpenSocket without issuing native descriptor queries.
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_.

Additional Inherited Members
Public Types inherited from proto_fuzzer::MockServerBase
using	MultiObserver = std::function<void(CURLM*)>
	Callback type used to publish the driving multi handle to observers.
Static Protected Member Functions inherited from proto_fuzzer::MockServerBase
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 inherited from proto_fuzzer::MockServerBase
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 inherited from proto_fuzzer::MockServerBase
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.

Detailed Description

Services curl's single-connection binary MQTT exchange.

MQTT has no line grammar: every packet starts with a one-byte fixed header (message type plus flags) followed by a 1-4 byte base-128 remaining-length field. This peer therefore treats Scenario.connection as opaque server bytes rather than a command/reply script:

initial_response is queued as soon as curl opens the socket and is expected to contain a CONNACK (20 02 00 00).
The peer reads and reassembles complete client packets from the same socket, using the fixed header and remaining length to find boundaries.
CONNECT needs no synthetic reply because the CONNACK was preloaded.
SUBSCRIBE receives a synthesized SUBACK that echoes its packet id. After that acknowledgement the peer releases the bounded on_readable chunks one at a time as server-initiated packets (for example PUBLISH followed by a server DISCONNECT).
PUBLISH is recorded as the fuzz-controlled topic and payload. A QoS 1 PUBLISH receives the matching PUBACK, even though the current curl revision always emits QoS 0.
PINGREQ receives PINGRESP. A client DISCONNECT only ends the packet stream; the peer still half-closes during cleanup.

All work remains in-process and non-waiting, so malformed packet headers terminate by the operation budget or a half-close instead of a timeout.

Subclasses replace the transport through CreateConnection(). The implicit- TLS MQTTS peer uses that hook to wrap the identical packet exchange in a verified OpenSSL connection; incoming bytes are observed after transport decoding so the parser does not depend on the carrier.

Definition at line 57 of file mqtt_mock_server.h.

Constructor & Destructor Documentation

◆ MqttMockServer()

proto_fuzzer::MqttMockServer::MqttMockServer ( curl::fuzzer::proto::MqttProbeMode mode = curl::fuzzer::proto::MQTT_PROBE_DEFAULT )

explicit

Begin without a borrowed protobuf or open socketpair.

RunLoop borrows a Scenario only for the synchronous DriveScenario call in which socket callbacks can run.

Parameters

mode	Closed harness-owned probe shape to apply before the transfer.

Definition at line 48 of file mqtt_mock_server.cc.

◆ ~MqttMockServer()

proto_fuzzer::MqttMockServer::~MqttMockServer ( )

overridedefault

Release the server-owned socketpair half after curl has returned its client descriptor.

The out-of-line destructor keeps MockConnection's complete type local to this translation unit.

Member Function Documentation

◆ active_pollset_probe_count()

std::size_t proto_fuzzer::MqttMockServer::active_pollset_probe_count ( ) const

Report how many requested zero-timeout multi-poll probes ran during the most recent drive.

RunLoop increments this only after a successful perform turn while curl still owns an active transfer and the MQTT socket is open.

Returns: Number of active, connected pollset probes in the previous drive.

Definition at line 96 of file mqtt_mock_server.cc.

◆ connect_count()

std::size_t proto_fuzzer::MqttMockServer::connect_count ( ) const

Returns: Number of CONNECT packets observed.

Definition at line 81 of file mqtt_mock_server.cc.

◆ CreateConnection()

std::unique_ptr< MockConnection > proto_fuzzer::MqttMockServer::CreateConnection ( )

protectedvirtual

Create the default plaintext transport for the MQTT packet exchange.

The MQTTS subclass overrides this factory while retaining the binary parser.

Returns: A new socketpair-backed connection.

Reimplemented in proto_fuzzer::MqttsMockServer.

Definition at line 143 of file mqtt_mock_server.cc.

◆ HandleOpenSocket()

curl_socket_t proto_fuzzer::MqttMockServer::HandleOpenSocket	(	curlsocktype	purpose = CURLSOCKTYPE_IPCXN,
		struct curl_sockaddr *	address = nullptr )

overrideprotectedvirtual

Create the single MQTT socketpair and queue the scenario's first server bytes.

curl sends CONNECT immediately, so a normal scenario preloads the CONNACK here; an empty or malformed greeting remains a reachable error path.

Parameters

purpose	Socket role requested by curl.
address	Unused stream destination metadata required by the callback signature.

Returns: Client descriptor for the MQTT channel, or CURL_SOCKET_BAD.

Implements proto_fuzzer::MockServerBase.

Definition at line 164 of file mqtt_mock_server.cc.

◆ ObserveIncomingData()

void proto_fuzzer::MqttMockServer::ObserveIncomingData	(	const unsigned char *	data,
		std::size_t	size )

overrideprotectedvirtual

Append decoded application bytes to the pending parser buffer.

The outer service loop drains this buffer after every transport call, so it remains bounded by the scenario's packet budget.

Parameters

data	First decoded byte.
size	Number of bytes available at data.

Implements proto_fuzzer::IncomingDataObserver.

Definition at line 150 of file mqtt_mock_server.cc.

◆ packet_count()

std::size_t proto_fuzzer::MqttMockServer::packet_count ( ) const

Returns: Number of complete client packets observed in the most recent drive.

Definition at line 78 of file mqtt_mock_server.cc.

◆ packet_transcript()

const std::string & proto_fuzzer::MqttMockServer::packet_transcript ( ) const

Returns: A prefix of complete client packets from the most recent drive.

Definition at line 69 of file mqtt_mock_server.cc.

◆ publish_count()

std::size_t proto_fuzzer::MqttMockServer::publish_count ( ) const

Returns: Number of PUBLISH packets observed.

Definition at line 84 of file mqtt_mock_server.cc.

◆ published_payload()

const std::string & proto_fuzzer::MqttMockServer::published_payload ( ) const

Returns: A prefix of the first PUBLISH packet's application payload.

Definition at line 75 of file mqtt_mock_server.cc.

◆ published_topic()

const std::string & proto_fuzzer::MqttMockServer::published_topic ( ) const

Returns: A prefix of the first PUBLISH packet's topic.

Definition at line 72 of file mqtt_mock_server.cc.

◆ qos1_publish_count()

std::size_t proto_fuzzer::MqttMockServer::qos1_publish_count ( ) const

Returns: Number of PUBLISH packets that requested QoS 1.

Definition at line 90 of file mqtt_mock_server.cc.

◆ RunLoop()

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

overrideprotectedvirtual

Alternate curl transitions with immediate peer service until the transfer completes or deterministic idle/operation caps win.

No select(), poll(), or sleep is needed: the CONNACK is preloaded, synthesized acknowledgements are written from the same thread, and scripted server packets are released one per turn so curl consumes the preceding acknowledgement first.

Parameters

multi	Multi handle containing easy.
easy	Easy handle already installed on this mock.
scenario	Connection script to borrow.

Implements proto_fuzzer::MockServerBase.

Definition at line 463 of file mqtt_mock_server.cc.

◆ subscribe_count()

std::size_t proto_fuzzer::MqttMockServer::subscribe_count ( ) const

Returns: Number of SUBSCRIBE packets observed.

Definition at line 87 of file mqtt_mock_server.cc.

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

proto_fuzzer/mqtt_mock_server.h
proto_fuzzer/mqtt_mock_server.cc

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ MqttMockServer()

◆ ~MqttMockServer()

Member Function Documentation

◆ active_pollset_probe_count()

◆ connect_count()

◆ CreateConnection()

◆ HandleOpenSocket()

◆ ObserveIncomingData()

◆ packet_count()

◆ packet_transcript()

◆ publish_count()

◆ published_payload()

◆ published_topic()

◆ qos1_publish_count()

◆ RunLoop()

◆ subscribe_count()