# frozen_string_literal: true require "resolv" require "ipaddr" module HTTPX module Plugins module Proxy module Socks4 VERSION = 4 CONNECT = 1 GRANTED = 90 PROTOCOLS = %w[socks4 socks4a].freeze Error = Class.new(Error) module ConnectionMethods private def transition(nextstate) return super unless @options.proxy && PROTOCOLS.include?(@options.proxy.uri.scheme) case nextstate when :connecting return unless @state == :idle @io.connect return unless @io.connected? req, _ = @pending.first return unless req request_uri = req.uri @write_buffer << Packet.connect(@options.proxy, request_uri) __socks4_proxy_connect when :connected return unless @state == :connecting @parser = nil end log(level: 1, label: "SOCKS4: ") { "#{nextstate}: #{@write_buffer.to_s.inspect}" } unless nextstate == :open super end def __socks4_proxy_connect @parser = SocksParser.new(@write_buffer, @options) @parser.once(:packet, &method(:__socks4_on_packet)) end def __socks4_on_packet(packet) _version, status, _port, _ip = packet.unpack("CCnN") if status == GRANTED req, _ = @pending.first request_uri = req.uri @io = ProxySSL.new(@io, request_uri, @options) if request_uri.scheme == "https" transition(:connected) throw(:called) else on_socks4_error("socks error: #{status}") end end def on_socks4_error(message) ex = Error.new(message) ex.set_backtrace(caller) on_error(ex) throw(:called) end end class SocksParser include Callbacks def initialize(buffer, options) @buffer = buffer @options = Options.new(options) end def close; end def consume(*); end def empty? true end def <<(packet) emit(:packet, packet) end end module Packet module_function def connect(parameters, uri) packet = [VERSION, CONNECT, uri.port].pack("CCn") begin ip = IPAddr.new(uri.host) raise Error, "Socks4 connection to #{ip} not supported" unless ip.ipv4? packet << [ip.to_i].pack("N") rescue IPAddr::InvalidAddressError if parameters.uri.scheme == "socks4" # resolv defaults to IPv4, and socks4 doesn't support IPv6 otherwise ip = IPAddr.new(Resolv.getaddress(uri.host)) packet << [ip.to_i].pack("N") else packet << "\x0\x0\x0\x1" << "\x7\x0" << uri.host end end packet << [parameters.username].pack("Z*") packet end end end end register_plugin :"proxy/socks4", Proxy::Socks4 end end