mirrors/arti.git/crates/tor-proto/src/channel/handler.rs, branch arti-v1.9.0

proto: Only allow VERSIONS cell for the new handshake state

2025-08-27T15:04:24Z

Due to this, it is not possible to get a VPADDING before because it requires a link protocol version to decideon the encoding: https://gitlab.torproject.org/tpo/core/torspec/-/issues/366 Signed-off-by: David Goulet

proto: Remove the AUTHORIZE as a parsable cell

2025-08-21T15:59:37Z

The AUTHORIZE cell command is simply reserved but not defined. The tor specification, at this point in time, is allowing such cell before the handshake starts but it is very unclear on what ordering is allowed nor how many can are allowed. C-tor silents drop them like VPADDING and so clearly unused. Instead of dealing with it, simply remove its support but keeping its reserved number. Signed-off-by: David Goulet

proto: Add a channel handler comment and a fix

2025-08-21T15:07:32Z

Signed-off-by: David Goulet

proto: Return AUTHORIZE, VPADDING and VERSIONS at handshake

2025-08-21T15:07:32Z

When starting a handshake, we were only expecting a VERSIONS which is not what the protocol say. An AUTHORIZE and VPADDING can arrive before a VERSIONS. Signed-off-by: David Goulet

proto: Cleanup allow(unused)

2025-08-20T17:22:16Z

Signed-off-by: David Goulet

proto: Unit tests for channel handler

2025-08-20T17:22:16Z

Signed-off-by: David Goulet

proto: Make the OutboundClientHandshake use new cell handler

2025-08-20T17:22:16Z

Use the ChannelFrame<> for the entirety of the outbound client handshake that is the ClientInitiator channel type. With this change, the codec.rs code is not needed anymore along its CodecError as well which has been normalized onto the crate::Error instead in order to simplify error handling and avoid duplication of error types. Unit tests have been modified to reflect this change of what can be done with a channel frame. Also renamed to focus on client behavior. Part of #1597 Signed-off-by: David Goulet

proto: Add channel cell handler

2025-08-20T17:22:16Z

The handler.rs file contains a generic "ChannelCellHandler" which is split into three different handler depending of the channel state (new, handshaking or open). These handlers implement Encoder/Decoder so we can give a ChannelCellHandler to a asynchronous_codec::Framed along a TLS stream. That cell handler is also in charge of tracking the CLOG/SLOG (see tor-spec), running digest of cells seen, which is used to authenticate a channel for the Relay <-> Relay case. This ChannelCellHandler auto transitions as the setters function are used. The handshake code will use this to advance the handler. Each handler uses a MessageFilter from msg.rs in order to allow or not to return the message. A keen eye will notice that we can avoid encoding a message if we don't need but we will decode all possible messages and only then allow it or not. The channel cell handler is not used at this commit. Part of #1597 Signed-off-by: David Goulet