shurikk · April 26, 2014 03:22 · Apr 26, 2014
diff --git a/tcp_socket_proxy_monkey_patch.rb b/tcp_socket_proxy_monkey_patch.rb
@@ -0,0 +1,80 @@
+# Usage:
+#
+# TCPSocket.socks_server = "socks-proxy.example.net"
+# TCPSocket.socks_port   = 8888
+
+require 'socket'
+
+class TCPSocket
+
+  alias :direct_to :initialize
+
+  class << self
+    attr_accessor :socks_server, :socks_port
+  end
+
+  def initialize(host, port, local_host = nil, local_port = nil)
+    socks_server = self.class.socks_server
+    socks_port   = self.class.socks_port
+
+    if socks_server && socks_port
+      direct socks_server, socks_port
+      authenticate
+      proxy_to(host, port)
+    else
+      direct_to host, port, local_host, local_port
+    end
+  end
+
+  def authenticate
+    # no authentication
+    write "\005\001\000"
+    recv(2)
+  end
+
+  def proxy_to(host, port)
+    ["\005", "\001", "\000"].map {|b| write b }
+
+    if host =~ /^(\d+)\.(\d+)\.(\d+)\.(\d+)$/
+      write "\001"
+      write [$1.to_i, $2.to_i, $3.to_i, $4.to_i].pack("CCCC")
+    elsif host =~ /^[:0-9a-f]+$/
+      raise "TCP/IPv6 is not supported via SOCKS"
+    else
+      write "\003" + [host.size].pack("C") + host
+    end
+
+    write [port].pack('n')
+
+    receive_via_proxy
+  end
+
+  def receive_via_proxy
+    reply = recv(4)
+
+    raise "SOCKS version #{reply[0..0]} is not supported" if reply[0..0] != "\005"
+    raise "SOCKS error: #{reply.bytes.to_a.inspect}" if reply[1..1] != "\000"
+
+    bind_addr_len = case reply[3..3]
+      when "\001"
+        4
+      when "\003"
+        recv(1).bytes.first
+      when "\004"
+        16
+      else
+        raise "SOCKS error: #{reply.bytes.to_a.inspect}"
+      end
+
+    bind_addr_s = recv(bind_addr_len)
+
+    bind_addr = case reply[3..3]
+      when "\001"
+        bind_addr_s.bytes.to_a.join(".")
+      when "\003"
+        bind_addr_s
+      end
+
+    [bind_addr, recv(bind_addr_len + 2).unpack("n")]
+  end
+end