raw_socks5.rb

require "bundler"

Bundler.require

require "addressable"
require "socket"
require "ipaddr"

proxy_address = Addressable::URI.parse("socks5://user:password@host:1080")
remote_ip = IPAddr.new(IPSocket::getaddress("icanhazip.com"))
remote_port = 80

socket = TCPSocket.new(proxy_address.host, proxy_address.port)
# version 5, 2 authentication methods, 0 (no auth) and 2 (username and password)
socket << [
  5, # SOCKS version 5
  2, # we support 2 authentication methods
  0, # 1: no authentication
  2  # 2: username/password authentication
].pack("CCCC")

version, authentication_method = socket.read(2).unpack("CC")
puts "server version #{version} and auth method chosen #{authentication_method}"
if authentication_method == 0
  puts "no auth required"
elsif authentication_method == 2
  puts "using username and password from uri"
  username = proxy_address.user[0, 255]
  password = proxy_address.password[0, 255]
  socket << [
    1, # authentication version 1
    username.size, # size of the username
    username, # username
    password.size, # size of the password
    password # password
  ].pack("CCA#{username.size}CA#{password.size}")

  version, status = socket.read(2).unpack("CC")

  if status == 0
    puts "authenticated ok"
    puts "connecting to #{remote_ip}:#{remote_port}"

    socket << [
      5, # SOCKS version 5
      1, # open a TCP/IP stream
      0, # reserved, should be 0
      1, # 1 = IPv4
      remote_ip.to_i, # 32-bit network order ip address
      remote_port # 16-bit network order port number
    ].pack("CCCCNn")

    version, status, _reserved, address_type = socket.read(4).unpack("CCCC")

    if status != 0
      puts "socks failed to connect"
      exit
    end

    puts "server version #{version}, status: #{status}, address type #{address_type}"

    if address_type == 1 # Bound to an IPv4 address
      bound_ip_address = IPAddr::new_ntoh(socket.read(4))
      puts "server bound to ip: #{bound_ip_address}"
    elsif address_type == 0x03 # Bound to a domain name
      puts "domain name"
      length = socket.read(1).unpack("C").first
      bound_hostname = socket.recv(length)
      puts "server bound to hostname: #{bound_hostname}"
    elsif address_type == 0x04 # Bound to an IPv6 address
      puts "ip v6"
      socket.recv(16) # can't be bothered to work out how to decode this
    end

    bound_port = socket.read(2).unpack("n").first
    puts "server bound to port: #{bound_port}"

    socket << "GET / HTTP/1.1\r\nHost: icanhazip.com\r\n\r\n"
    result = ""
    while !socket.eof?
      result = "#{result}#{socket.gets}"
    end
    puts "result: #{result}"
  else
    puts "unknown status returned #{status}"
  end
end

socket.close

puts "done"