Crate hopr_protocol_session

Contains implementation of a Session message protocol.

The implementation in this crate follows the HOPR RFC-0007.

What is Session protocol?

Session protocol is a simple protocol for unreliable networks that implements basic TCP-like features, such as segmentation, retransmission and acknowledgement.

The goal of this protocol is to establish a read-write session between two parties, where one is a message sender and the other one is the receiver. The messages are called frames which are split and are delivered as segments from the sender to the recipient. The session has some reliability guarantees given by the retransmission and acknowledgement capabilities of individual segments.

The UnreliableSocket acts as an unreliable Session protocol socket, taking care only of segmentation, reassembly and sequencing.

The ReliableSocket has (in addition to segmentation, reassembly and sequencing) an internal state that allows acknowledging frames, retransmit unacknowledged frames and/or requesting of missing frame segments. It therefore offers data some delivery guarantees up to the pre-defined frame expiration time.

The above sockets can be constructed on top of any transport that implements [futures::io::AsyncRead] and [futures::io::AsyncWrite], also using the extension methods.

Overview of the crate

• Protocol messages are defined in the protocol submodule.
• Socket-like Session interface is defined in socket submodule.
• Frames and segments are defined in the frames module.
• Segmentation, reassembly and sequencing are defined in the processing submodule.

Modules

errors

Contains errors thrown from this module.

Structs

AcknowledgementState

Represents a Session socket state is able to process acknowledgements.

AcknowledgementStateConfig

Configuration object of the AcknowledgementState.

SessionSocket

Socket-like object implementing the Session protocol that can operate on any transport that implements [futures::io::AsyncRead] and [futures::io::AsyncWrite].

SessionSocketConfig

Configuration object for SessionSocket.

Stateless

Represents a stateless Session socket.

Enums

AcknowledgementMode

Indicates the acknowledgement mode of a stateful Session socket.

Traits

SessionSocketExt

Adaptors for [futures::io::AsyncRead] + [futures::io::AsyncWrite] transport to use Session protocol.

SocketState

Abstraction of the SessionSocket state.

Functions

session_socket_mtu

Computes the Session Socket MTU, given the MTU C of the underlying socket.

Type Aliases

ReliableSocket

Represents a socket with reliable delivery.

UnreliableSocket

Represents a stateless (and therefore unreliable) socket.