ex_wire

v0.1.1

ex_wire v0.1.1 ExWire.Adapter.TCP

Starts a TCP server to handle incoming and outgoing RLPx, DevP2P, Eth Wire connection.

Once this connection is up, it’s possible to add a subscriber to the different packets that are sent over the connection. This is the primary way of handling packets.

Note: incoming connections are not fully tested at this moment. Note: we do not currently store token to restart connections (this upsets some peers)

Link to this section Summary

Functions

handle_call(msg, from, state)

Allows a client to subscribe to incoming packets. Subscribers must be in the form of {module, function, args}, in which case we’ll call module.function(packet, ...args), or {:server, server_pid} for a GenServer, in which case we’ll send a message {:packet, packet, peer}

handle_cast(msg, state)

If we receive a send and we have secrets set, we’ll send the message as a framed Eth packet

handle_info(msg, state)

Handle info will handle when we have inbound communucation from a peer node

init(args)

Initialize by opening up a gen_tcp connection to given host and port

send_hello(pid)

Client function to send HELLO message after connecting

send_packet(pid, packet)

Client function for sending a packet over to a peer

start_link(atom, peer, subscribers \\ [])

Starts an outbound peer to peer connection

subscribe(pid, subscription)

Client function to subscribe to incoming packets

Link to this section Functions

Link to this function handle_call(msg, from, state)

Allows a client to subscribe to incoming packets. Subscribers must be in the form of {module, function, args}, in which case we’ll call module.function(packet, ...args), or {:server, server_pid} for a GenServer, in which case we’ll send a message {:packet, packet, peer}.

Link to this function handle_cast(msg, state)

If we receive a send and we have secrets set, we’ll send the message as a framed Eth packet.

However, if we haven’t yet sent a Hello message, we should queue the message and try again later. Most servers will disconnect if we send a non-Hello message as our first message.

Link to this function handle_info(msg, state)

Handle info will handle when we have inbound communucation from a peer node.

If we haven’t yet completed our handshake, we’ll await an auth or ack message as appropriate. That is, if we’ve established the connection and have sent an auth message, then we’ll look for an ack. If we listened for a connection, we’ll await an auth message.

TODO: clients may send an auth before (or as) we do, and we should handle this case without error.

Link to this function init(args)

Initialize by opening up a gen_tcp connection to given host and port.

We’ll also prepare and send out an authentication message immediately after connecting.

Link to this function send_hello(pid)

Client function to send HELLO message after connecting.

Link to this function send_packet(pid, packet) 
send_packet(pid, struct) :: :ok

Client function for sending a packet over to a peer.

Link to this function start_link(atom, peer, subscribers \\ [])

Starts an outbound peer to peer connection.

Link to this function subscribe(pid, subscription) 
subscribe(pid, {module, atom, list} | {:server, pid}) :: :ok

Client function to subscribe to incoming packets.

A subscription should be in the form of {:server, server_pid}, and we will send a packet to that server with contents {:packet, packet, peer} for each received packet.