Module: Hop::TcpBearer

Defined in:
lib/hop/tcp_bearer.rb

Overview

The raw-TCP Internet bearer: opaque Hop frames over TCP, core does the Noise. TCP is a stream, so each drained packet is length-prefixed (4-byte big-endian) and reassembled on the far side.

Constant Summary collapse

MAX_FRAME_BYTES = 
1 << 20

Class Method Summary collapse

Class Method Details

.dial(endpoint, host, port) ⇒ Object 



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# File 'lib/hop/tcp_bearer.rb', line 96

def self.dial(endpoint, host, port)
  sock = TCPSocket.new(host, port)
  link = next_link
  endpoint.register_link(link, :dialer, ->(buf) { send_framed(sock, buf) })
  endpoint.register_closer { sock.close rescue nil }
  Thread.new { recv_loop(endpoint, sock, link) }
  sock
end

.listen(endpoint, port, host: "0.0.0.0") ⇒ Object 



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# File 'lib/hop/tcp_bearer.rb', line 54

def self.listen(endpoint, port, host: "0.0.0.0")
  server = TCPServer.new(host, port)
  sockets = {}
  sockets_mutex = Mutex.new
  closing = false
  endpoint.register_closer do
    sockets_mutex.synchronize do
      closing = true
      server.close rescue nil
      sockets.each_key { |socket| socket.close rescue nil }
    end
  end
  Thread.new do
    loop do
      sock = begin
        server.accept
      rescue StandardError
        break
      end
      reject = sockets_mutex.synchronize do
        if closing
          true
        else
          sockets[sock] = true
          false
        end
      end
      if reject
        sock.close rescue nil
        next
      end
      link = next_link
      endpoint.register_link(link, :acceptor, ->(buf) { send_framed(sock, buf) })
      Thread.new do
        recv_loop(endpoint, sock, link)
        sockets_mutex.synchronize { sockets.delete(sock) }
      end
    end
  end
  server
end

.next_link ⇒ Object 



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# File 'lib/hop/tcp_bearer.rb', line 12

def self.next_link = @seq_mutex.synchronize { @seq += 1 }

.read_exact(sock, n) ⇒ Object 



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# File 'lib/hop/tcp_bearer.rb', line 20

def self.read_exact(sock, n)
  data = +"".b
  while data.bytesize < n
    chunk = sock.read(n - data.bytesize)
    return nil unless chunk

    data << chunk
  end
  data
end

.recv_loop(endpoint, sock, link) ⇒ Object 



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# File 'lib/hop/tcp_bearer.rb', line 31

def self.recv_loop(endpoint, sock, link)
  loop do
    hdr = read_exact(sock, 4)
    break unless hdr

    n = hdr.unpack1("N")
    break if n > MAX_FRAME_BYTES
    frame = n.zero? ? "".b : read_exact(sock, n)
    break unless frame

    endpoint.deliver(link, frame)
  end
rescue IOError, Errno::ECONNRESET, Errno::EBADF
  nil
ensure
  endpoint.link_down(link)
  begin
    sock.close
  rescue StandardError
    nil
  end
end

.send_framed(sock, buf) ⇒ Object 



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# File 'lib/hop/tcp_bearer.rb', line 14

def self.send_framed(sock, buf)
  sock.write([buf.bytesize].pack("N") + buf)
rescue IOError, Errno::EPIPE, Errno::ECONNRESET, Errno::EBADF
  nil
end