or Directory Reference

core/or: Onion routing happens here!

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Files
file	addr_policy_st.h [code]
	Address policy structures.
file	address_set.c [code]
	Implementation for a set of addresses.
file	address_set.h [code]
	Types to handle sets of addresses.
file	cell_queue_st.h [code]
	Cell queue structures.
file	cell_st.h [code]
	Fixed-size cell structure.
file	channel.c [code]
	OR/OP-to-OR channel abstraction layer. A channel's job is to transfer cells from Tor instance to Tor instance. Currently, there is only one implementation of the channel abstraction: in channeltls.c.
file	channel.h [code]
	Header file for channel.c.
file	channelpadding.c [code]
	Link-level padding code.
file	channeltls.c [code]
	A concrete subclass of channel_t using or_connection_t to transfer cells between Tor instances.
file	channeltls.h [code]
	Header file for channeltls.c.
file	circuit_st.h [code]
	Base circuit structure.
file	circuitbuild.c [code]
	Implements the details of building circuits (by choosing paths, constructing/sending create/extend cells, and so on).
file	circuitbuild.h [code]
	Header file for circuitbuild.c.
file	circuitlist.c [code]
	Manage global structures that list and index circuits, and look up circuits within them.
file	circuitlist.h [code]
	Header file for circuitlist.c.
file	circuitmux.c [code]
	Circuit mux/cell selection abstraction.
file	circuitmux.h [code]
	Header file for circuitmux.c.
file	circuitmux_ewma.c [code]
	EWMA circuit selection as a circuitmux_t policy.
file	circuitmux_ewma.h [code]
	Header file for circuitmux_ewma.c.
file	circuitpadding.c [code]
	Circuit-level padding implementation.
file	circuitpadding.h [code]
	Header file for circuitpadding.c.
file	circuitpadding_machines.c [code]
	Circuit padding state machines.
file	circuitpadding_machines.h [code]
	Header file for circuitpadding_machines.c.
file	circuitstats.c [code]
	Maintains and analyzes statistics about circuit built times, so we can tell how long we may need to wait for a fast circuit to be constructed.
file	circuitstats.h [code]
	Header file for circuitstats.c.
file	circuituse.c [code]
	Launch the right sort of circuits and attach the right streams to them.
file	circuituse.h [code]
	Header file for circuituse.c.
file	command.c [code]
	Functions for processing incoming cells.
file	command.h [code]
	Header file for command.c.
file	connection_edge.c [code]
	Handle edge streams.
file	connection_edge.h [code]
	Header file for connection_edge.c.
file	connection_or.c [code]
	Functions to handle OR connections, TLS handshaking, and cells on the network.
file	connection_or.h [code]
	Header file for connection_or.c.
file	connection_st.h [code]
	Base connection structure.
file	cpath_build_state_st.h [code]
	Circuit-build-stse structure.
file	crypt_path.c [code]
	Functions dealing with layered circuit encryption. This file aims to provide an API around the crypt_path_t structure which holds crypto information about a specific hop of a circuit.
file	crypt_path.h [code]
	Header file for crypt_path.c.
file	crypt_path_reference_st.h [code]
	reference-counting structure for crypt_path_t
file	crypt_path_st.h [code]
	Path structures for origin circuits.
file	destroy_cell_queue_st.h [code]
	Destroy-cell queue structures.
file	dos_config.c [code]
	Code to interpret the user's configuration of DoS module.
file	dos_config.h [code]
	Header for core/or/dos_config.c.
file	dos_options.inc [code]
	Declare configuration options for the DoS module.
file	dos_options_st.h [code]
	Structure dos_options_t to hold options for the DoS subsystem.
file	dos_sys.c [code]
	Subsystem definitions for DOS module.
file	dos_sys.h [code]
	Header for core/or/dos_sys.c.
file	edge_connection_st.h [code]
	Edge-connection structure.
file	entry_connection_st.h [code]
	Entry connection structure.
file	entry_port_cfg_st.h [code]
	Configuration structure for client ports.
file	extend_info_st.h [code]
	Extend-info structure.
file	extendinfo.c [code]
	Functions for creating and using extend_info_t objects.
file	extendinfo.h [code]
	Header for core/or/extendinfo.c.
file	half_edge_st.h [code]
	Half-open connection structure.
file	listener_connection_st.h [code]
	Listener connection structure.
file	lttng_circuit.inc [code]
	LTTng tracing probe declaration for the circuit subsystem. It is in this .inc file due to the non C standard syntax and the way we guard the header with the LTTng specific TRACEPOINT_HEADER_MULTI_READ.
file	ocirc_event.c [code]
	Publish state change messages for origin circuits.
file	ocirc_event.h [code]
	Header file for ocirc_event.c.
file	onion.c [code]
	Functions to queue create cells, and parse and create the CREATE cell and its allies.
file	onion.h [code]
	Header file for onion.c.
file	or.h [code]
	Master header file for Tor-specific functionality.
file	or_connection_st.h [code]
	OR connection structure.
file	or_handshake_certs_st.h [code]
	OR handshake certs structure.
file	or_handshake_state_st.h [code]
	OR handshake state structure.
file	or_periodic.c [code]
	Periodic callbacks for the onion routing subsystem.
file	or_periodic.h [code]
	Header for core/or/or_periodic.c.
file	or_sys.c [code]
	Subsystem definitions for OR module.
file	or_sys.h [code]
	Header for core/or/or_sys.c.
file	orconn_event.c [code]
	Publish state change messages for OR connections.
file	orconn_event.h [code]
	Header file for orconn_event.c.
file	origin_circuit_st.h [code]
	Origin circuit structure.
file	policies.c [code]
	Code to parse and use address policies and exit policies.
file	policies.h [code]
	Header file for policies.c.
file	port_cfg_st.h [code]
	Listener port configuration structure.
file	protover.c [code]
	Versioning information for different pieces of the Tor protocol.
file	protover.h [code]
	Headers and type declarations for protover.c.
file	reasons.c [code]
	Convert circuit, stream, and orconn error reasons to and/or from strings and errno values.
file	reasons.h [code]
	Header file for reasons.c.
file	relay.c [code]
	Handle relay cell encryption/decryption, plus packaging and receiving from circuits, plus queuing on circuits.
file	relay.h [code]
	Header file for relay.c.
file	relay_crypto_st.h [code]
	Relay-cell encryption state structure.
file	scheduler.c [code]
	Channel scheduling system: decides which channels should send and receive when.
file	scheduler.h [code]
	Header file for scheduler*.c.
file	scheduler_kist.c [code]
	Implements the KIST cell scheduler.
file	scheduler_vanilla.c [code]
	"Vanilla" (pre-KIST) cell scheduler code.
file	sendme.c [code]
	Code that is related to SENDME cells both in terms of creating/parsing cells and handling the content.
file	sendme.h [code]
	Header file for sendme.c.
file	server_port_cfg_st.h [code]
	Configuration structure for server ports.
file	socks_request_st.h [code]
	Client request structure.
file	status.c [code]
	Collect status information and log heartbeat messages.
file	status.h [code]
	Header for status.c.
file	tor_version_st.h [code]
	Parsed Tor version structure.
file	trace_probes_circuit.c [code]
	Tracepoint provider source file for the circuit subsystem. Probes are generated within this C file for LTTng-UST.
file	var_cell_st.h [code]
	Variable-length cell structure.
file	versions.c [code]
	Code to manipulate, parse, and compare Tor versions.
file	versions.h [code]
	Header file for versions.c.

Detailed Description

core/or: Onion routing happens here!

This is the central part of Tor that handles the core tasks of onion routing: building circuit, handling circuits, attaching circuit to streams, moving data around, and so forth.

Some aspects of this module should probably be refactored into others.

Notable files here include:

channel.c : Generic channel implementation. Channels handle sending and receiving cells among tor nodes.

channeltls.c : Channel implementation for TLS-based OR connections. Uses connection_or.c.

circuitbuild.c : Code for constructing circuits and choosing their paths. (Note: this module could plausibly be split into handling the client side, the server side, and the path generation aspects of circuit building.)

circuitlist.c : Code for maintaining and navigating the global list of circuits.

circuitmux.c : Generic circuitmux implementation. A circuitmux handles deciding, for a particular channel, which circuit should write next.

circuitmux_ewma.c : A circuitmux implementation based on the EWMA (exponentially weighted moving average) algorithm.

circuituse.c : Code to actually send and receive data on circuits.

command.c : Handles incoming cells on channels.

connection.c : Generic and common connection tools, and implementation for the simpler connection types.

connection_edge.c : Implementation for entry and exit connections.

connection_or.c : Implementation for OR connections (the ones that send cells over TLS).

onion.c : Generic code for generating and responding to CREATE and CREATED cells, and performing the appropriate onion handshakes. Also contains code to manage the server-side onion queue.

relay.c : Handles particular types of relay cells, and provides code to receive, encrypt, route, and interpret relay cells.

scheduler.c : Decides which channel/circuit pair is ready to receive the next cell.