Files
frajtano/lib/peer.ex
2024-09-21 16:12:04 +01:00

113 lines
3.2 KiB
Elixir

defmodule Frajtano.Peer do
alias Frajtano.Proto
require Logger
use GenServer, restart: :temporary
def start(path) do
DynamicSupervisor.start_child(Frajtano.Peer, {__MODULE__, path})
end
def start_link(path) do
GenServer.start_link(__MODULE__, path)
end
@impl true
def init(path) do
{:ok, conn} = :gen_tcp.connect({:local, path}, 0, [:binary, active: :once])
{:ok, %{conn: conn, clients: :queue.new(), buffer: <<>>}}
end
def reply({client, ref}, msg) do
send(client, {ref, msg})
end
defp handle_messages(%{clients: clients, buffer: buffer} = state) do
case Proto.decode(buffer) do
{nil, buffer} ->
{:noreply, %{state | buffer: buffer}}
{msg, buffer} ->
{{:value, client}, clients} = :queue.out(clients)
reply(client, {:ok, msg})
handle_messages(%{state | clients: clients, buffer: buffer})
end
end
@impl true
def handle_info({:send, packet, from}, %{conn: conn, clients: clients} = state) do
case :gen_tcp.send(conn, Proto.encode(packet)) do
:ok ->
{:noreply, %{state | clients: :queue.in(from, clients)}}
{:error, e} ->
{:noreply, state, {:continue, {:error, e}}}
end
end
@impl true
def handle_info({:tcp, conn, msg}, %{conn: conn, buffer: buffer} = state) do
:inet.setopts(conn, active: :once)
buffer = buffer <> msg
handle_messages(%{state | buffer: buffer})
end
@impl true
def handle_info({:tcp_closed, _}, state) do
{:noreply, state, {:continue, {:error, :closed}}}
end
@impl true
def handle_info(:timeout, state) do
{:noreply, state, {:continue, {:error, :closed}}}
end
@impl true
def handle_continue({:error, e}, %{clients: clients}) do
clients
|> :queue.to_list()
|> Enum.each(&reply(&1, {:error, e}))
{:stop, {:error, e}, %{}}
end
def identities(peer) do
ref = make_ref()
send(peer, {:send, {:agentc_request_identities, nil}, {self(), ref}})
# Needs to be less than the timeout in Frajtano.Agent.identities on the Task.async_stream call
# That's 5000 by default
timer = Process.send_after(peer, :timeout, 4500)
receive do
{^ref, msg} ->
Process.cancel_timer(timer)
msg
end
|> case do
{:ok, {:agent_identities_answer, identities}} -> {:ok, identities}
{:ok, {:agent_failure, nil}} -> {:error, :agent_failure}
{:ok, msg} -> raise("Unexpected message #{inspect(msg)}")
{:error, e} -> {:error, e}
end
end
def sign(peer, request) do
# Signing may take some time, as a password may need to be entered or similar
# There is therefore no timeout
# If something requests identities afterwards, it will timeout, which also kills this signature request
# The SSH agent protocol strict ordering leaves fun problems with timeouts, as it turns out
ref = make_ref()
send(peer, {:send, {:agentc_sign_request, request}, {self(), ref}})
receive do
{^ref, msg} -> msg
end
|> case do
{:ok, {:agent_sign_response, signature}} -> {:ok, signature}
{:ok, {:agent_failure, nil}} -> {:error, :agent_failure}
{:ok, msg} -> raise("Unexpected message #{inspect(msg)}")
{:error, e} -> {:error, e}
end
end
end