Module channel

Source
Expand description

Code for talking directly (over a TLS connection) to a Tor client or relay.

Channels form the basis of the rest of the Tor protocol: they are the only way for two Tor instances to talk.

Channels are not useful directly for application requests: after making a channel, it needs to get used to build circuits, and the circuits are used to anonymize streams. The streams are the objects corresponding to directory requests.

In general, you shouldn’t try to manage channels on your own; use the tor-chanmgr crate instead.

To launch a channel:

One you have a running channel, you can create circuits on it with its Channel::new_circ method. See crate::circuit::PendingClientCirc for information on how to proceed from there.

§Design

For now, this code splits the channel into two pieces: a “Channel” object that can be used by circuits to write cells onto the channel, and a “Reactor” object that runs as a task in the background, to read channel cells and pass them to circuits as appropriate.

I’m not at all sure that’s the best way to do that, but it’s what I could think of.

§Limitations

This is client-only, and only supports link protocol version 4.

TODO: There is no channel padding.

TODO: There is no flow control, rate limiting, queueing, or fairness.

Re-exports§

pub use crate::channel::params::*;

Modules§

kist
KIST-related parameters.
padding
Channel padding
params
Parameters influencing all channels in a Tor client

Structs§

Channel
An open client channel, ready to send and receive Tor cells.
ChannelBuilder
Structure for building and launching a Tor channel.
CloseInfo
The status of a channel which was closed successfully.
OutboundClientHandshake
A raw client channel on which nothing has been done.
UniqId
Unique identifier for a channel.
UnverifiedChannel
A client channel on which versions have been negotiated and the relay’s handshake has been read, but where the certs have not been checked.
VerifiedChannel
A client channel on which versions have been negotiated, relay’s handshake has been read, but the client has not yet finished the handshake.

Enums§

ClosedUnexpectedly
The status of a channel which closed unexpectedly.
CreateResponse
A subclass of ChanMsg that can arrive in response to a CREATE* cell that we send.
CtrlMsg
A message telling the channel reactor to do something.

Constants§

CHANNEL_BUFFER_SIZE
The size of the channel buffer for communication between Channel and its reactor.