Real, nonblocking UDP peer for curl's TFTP state machine. More...

#include <tftp_mock_server.h>

Inheritance diagram for proto_fuzzer::TftpMockServer:

Public Member Functions
	TftpMockServer ()
	Start without live descriptors or borrowed scenario storage.
	~TftpMockServer () override
	Close the two server endpoints after the base drive has removed curl's separately-owned client descriptor from its multi handle.
void	ObserveState () override
	Retain protocol outcomes in coverage and introspector builds.
const std::vector< TftpReceivedDatagram > &	received_datagrams () const
	Return bounded observations from the most recent run rather than parsing them in the peer.
std::uint16_t	request_port () const
	Expose the kernel-selected request endpoint for transfer-ID assertions, not for routing.
std::uint16_t	transfer_port () const
	Expose the kernel-selected response endpoint for transfer-ID assertions, not for routing.
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
curl_socket_t	HandleOpenSocket (curlsocktype purpose, struct curl_sockaddr *address) override
	Create both server transfer IDs before returning curl's client socket.
SocketSetupDisposition	GetSocketSetupDisposition (curl_socket_t curlfd, curlsocktype purpose) const override
	TFTP returns an unconnected IPv4 datagram descriptor, so curl must still bind/configure it before the first sendto.
void	RunLoop (CURLM multi, CURL easy, const curl::fuzzer::proto::Scenario &scenario) override
	Give curl one nonblocking state-machine turn, retain all client packets that turn produced, then release at most one peer packet.
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.
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

Real, nonblocking UDP peer for curl's TFTP state machine.

An AF_UNIX socketpair cannot model TFTP: curl binds the returned descriptor as an IP datagram socket and uses sendto/recvfrom with a mutable transfer address. This peer binds two ephemeral loopback endpoints. The request endpoint receives RRQ/WRQ, while every response originates at the transfer endpoint so curl exercises the RFC transfer-ID pinning path.

Connection.initial_response, when nonempty, is the first response datagram. Each retained Connection.on_readable value is one subsequent datagram, including an explicitly empty value. A single datagram is released after each curl state-machine turn, which preserves packet boundaries and permits duplicates, unexpected blocks, and malformed packets without a thread or wall-clock wait.

Definition at line 60 of file tftp_mock_server.h.

Constructor & Destructor Documentation

◆ TftpMockServer()

proto_fuzzer::TftpMockServer::TftpMockServer ( )

Start without live descriptors or borrowed scenario storage.

RunLoop builds both immediately before the first curl_multi_perform that can observe them.

Definition at line 26 of file tftp_mock_server.cc.

Member Function Documentation

◆ GetSocketSetupDisposition()

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

overrideprotectedvirtual

TFTP returns an unconnected IPv4 datagram descriptor, so curl must still bind/configure it before the first sendto.

Parameters

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

Returns: Whether curl must perform its normal socket setup.

Reimplemented from proto_fuzzer::MockServerBase.

Definition at line 66 of file tftp_mock_server.cc.

◆ HandleOpenSocket()

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

overrideprotectedvirtual

Create both server transfer IDs before returning curl's client socket.

The first response deliberately comes from a port different from the rewritten request destination, matching real TFTP and making curl's address-pinning transition observable through where its next ACK/DATA arrives. Curl owns the client descriptor after a successful return.

Parameters

purpose	Socket purpose supplied by curl's open-socket callback.
address	Mutable destination storage supplied by curl.

Returns: client UDP descriptor, or CURL_SOCKET_BAD on setup failure.

Implements proto_fuzzer::MockServerBase.

Definition at line 196 of file tftp_mock_server.cc.

◆ received_datagrams()

const std::vector< TftpReceivedDatagram > & proto_fuzzer::TftpMockServer::received_datagrams ( ) const

Return bounded observations from the most recent run rather than parsing them in the peer.

Tests can assert exact RRQ/WRQ/DATA/ACK bytes while production fuzz iterations pay only the bounded copies needed for those observations.

Returns: Borrowed observations that remain valid until the next drive or destruction of this server.

Definition at line 49 of file tftp_mock_server.cc.

◆ request_port()

std::uint16_t proto_fuzzer::TftpMockServer::request_port ( ) const

Expose the kernel-selected request endpoint for transfer-ID assertions, not for routing.

Returns: request UDP port in host byte order, or zero before socket setup.

Definition at line 54 of file tftp_mock_server.cc.

◆ RunLoop()

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

overrideprotectedvirtual

Give curl one nonblocking state-machine turn, retain all client packets that turn produced, then release at most one peer packet.

Completion gets one final drain so the terminal ACK remains observable. Incomplete scripts stop after a small idle prefix rather than waiting for TFTP's one-second retry clock, keeping mutation throughput independent of wall time.

Parameters

multi	Multi handle containing the scenario's easy handle.
easy	Easy handle being driven; all work is reached through multi.
scenario	Scenario whose primary Connection supplies UDP packets.

Implements proto_fuzzer::MockServerBase.

Definition at line 311 of file tftp_mock_server.cc.

◆ transfer_port()

std::uint16_t proto_fuzzer::TftpMockServer::transfer_port ( ) const

Expose the kernel-selected response endpoint for transfer-ID assertions, not for routing.

Returns: transfer UDP port in host byte order, or zero before socket setup.

Definition at line 59 of file tftp_mock_server.cc.

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

proto_fuzzer/tftp_mock_server.h
proto_fuzzer/tftp_mock_server.cc

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ TftpMockServer()

Member Function Documentation

◆ GetSocketSetupDisposition()

◆ HandleOpenSocket()

◆ received_datagrams()

◆ request_port()

◆ RunLoop()

◆ transfer_port()