Expand description
§tor-cell
Coding and decoding for the cell types that make up Tor’s protocol
§Overview
Tor’s primary network protocol is oriented around a set of messages called “Cells”. They exist at two primary layers of the protocol: the channel-cell layer, and the relay-cell layer.
Channel cells are sent between relays, or between a client and a relay, over a TLS connection. Each of them encodes a single Channel Message. Channel messages can affect the channel itself (such as those used to negotiate and authenticate the channel), but more frequently are used with respect to a given multi-hop circuit.
Channel message that refer to a circuit do so with a channel-local identifier called a Circuit ID. These messages include CREATE2 (used to extend a circuit to a first hop) and DESTROY (used to tear down a circuit). But the most frequently used channel message is RELAY, which is used to send a message to a given hop along a circuit.
Each RELAY cell is encrypted and decrypted (according to protocols not implemented in this crate) until it reaches its target. When it does, it is decoded into a single Relay Message. Some of these relay messages are used to manipulate circuits (e.g., by extending the circuit to a new hop); others are used to manipulate anonymous data-streams (by creating them, ending them, or sending data); and still others are used for protocol-specific purposes (like negotiating with an onion service.)
For a list of most of the cell types used in Tor, see tor-spec.txt. Other cell types are defined in rend-spec-v3.txt (for onion services) and padding-spec.txt (for padding negotiation).
This crate is part of Arti, a project to implement Tor in Rust.
License: MIT OR Apache-2.0
Modules§
- Messages sent over Tor channels
- Implementation for parsing and encoding relay cells
- Declare a restricted variant of our message types.
Macros§
- Declare a restricted version of
AnyRelayMsgorAnyChanMsg.
Enums§
- An error type for the tor-cell crate.
Type Aliases§
- An error type for this crate.