Module reactor 

Module exposing the relay circuit reactor subsystem.

See reactor for a description of the overall architecture.

All cells moving in the forward direction (i.e. away from the client) are handled by the forward reactor, which deals with

• unrecognized RELAY* cells, by moving them in the forward direction (towards the exit)
• recognized RELAY* cells, by splitting each cell into messages, and handling each message individually as described in the table below (Note: since prop340 is not yet implemented, in practice there is only 1 message per cell).
• DESTROY cells, by tearing down the circuit, and causing a DESTROY to be sent forward, to the next hop, if there is one
• PADDING_NEGOTIATE cells (not yet implemented)

Legend: `F` = "forward reactor", `B` = "backward reactor", `S` = "stream reactor"
`FH` = `ForwardHandler`

| RELAY cmd  | Received in | Handled in            | Description                            |
|------------|-------------|-----------------------|----------------------------------------|
| DROP       | F           | FH::handle_meta_msg() | Passed to PaddingController for        |
|            |             |                       | validation                             |
|------------|-------------|-----------------------|----------------------------------------|
| EXTEND2    | F           | FH::handle_meta_msg() | Handled by the ExtendRequestHandler    |
|            |             |                       | See [forward::extend_handler].         |
|------------|-------------|-----------------------|----------------------------------------|
| TRUNCATE   | F           | FH::handle_meta_msg() | Not supported: TRUNCATE is considered  |
|            |             |                       | a protocol violation, because none of  |
|            |             |                       | of our implementations send it.        |
|------------|-------------|-----------------------|----------------------------------------|
| SENDME     | F           | B                     | Sent to BackwardReactor for handling.  |
| (sid = 0)  |             |                       | See the [crate::circuit::reactor] docs |
|------------|-------------|-----------------------|----------------------------------------|
| Other      | F           | FH::handle_meta_msg() | Rejected as unrecognized               |
| (sid = 0)  |             |                       |                                        |
|------------|-------------|-----------------------|----------------------------------------|
| Other      | F           | S                     | Handled in the `StreamReactor`         |
| (sid != 0) |             |                       |                                        |

Modules

backward 🔒

A relay’s view of the backward (towards the client) state of a circuit.

forward 🔒

A relay’s view of the forward (away from the client, towards the exit) state of a circuit.

Structs

Reactor 🔒

The entry point of the circuit reactor subsystem.

StreamHandler 🔒

A handler customizing the relay stream reactor.

Type Aliases

RelayBaseReactor 🔒

Type-alias for the relay base reactor type.