Add C++11 version of SOCKS4 example.

asio/boostify.pl

@@ -530,6 +530,8 @@ sub copy_examples
       "src/examples/cpp11/local",
       "src/examples/cpp11/multicast",
       "src/examples/cpp11/nonblocking",
+      "src/examples/cpp11/operations",
+      "src/examples/cpp11/socks4",
       "src/examples/cpp11/spawn",
       "src/examples/cpp11/ssl",
       "src/examples/cpp11/timeouts",

asio/src/doc/examples.qbk

@@ -444,6 +444,15 @@ library that wants to perform the I/O operations itself.
 * [@../src/examples/cpp11/nonblocking/third_party_lib.cpp] ([@examples/diffs/nonblocking/third_party_lib.cpp.html diff to C++03])
 
 
+[heading SOCKS 4]
+
+Example client program implementing the SOCKS 4 protocol for communication via
+a proxy.
+
+* [@../src/examples/cpp11/socks4/sync_client.cpp] ([@examples/diffs/socks4/sync_client.cpp.html diff to C++03])
+* [@../src/examples/cpp11/socks4/socks4.hpp] ([@examples/diffs/socks4/socks4.hpp.html diff to C++03])
+
+
 [heading Spawn]
 
 Example of using the asio::spawn() function, a wrapper around the

asio/src/examples/cpp11/Makefile.am

@@ -33,6 +33,7 @@ noinst_PROGRAMS = \
 	multicast/receiver \
 	multicast/sender \
 	nonblocking/third_party_lib \
+	socks4/sync_client \
 	timeouts/async_tcp_client \
 	timeouts/blocking_tcp_client \
 	timeouts/blocking_token_tcp_client \
@@ -98,6 +99,7 @@ iostreams_http_client_SOURCES = iostreams/http_client.cpp
 multicast_receiver_SOURCES = multicast/receiver.cpp
 multicast_sender_SOURCES = multicast/sender.cpp
 nonblocking_third_party_lib_SOURCES = nonblocking/third_party_lib.cpp
+socks4_sync_client_SOURCES = socks4/sync_client.cpp
 timeouts_async_tcp_client_SOURCES = timeouts/async_tcp_client.cpp
 timeouts_blocking_tcp_client_SOURCES = timeouts/blocking_tcp_client.cpp
 timeouts_blocking_token_tcp_client_SOURCES = timeouts/blocking_token_tcp_client.cpp

asio/src/examples/cpp11/socks4/.gitignore

@@ -0,0 +1,10 @@
+.deps
+.dirstamp
+*.o
+*.obj
+*.exe
+sync_client
+*.ilk
+*.manifest
+*.pdb
+*.tds

asio/src/examples/cpp11/socks4/socks4.hpp

@@ -0,0 +1,143 @@
+//
+// socks4.hpp
+// ~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef SOCKS4_HPP
+#define SOCKS4_HPP
+
+#include <array>
+#include <string>
+#include <asio/buffer.hpp>
+#include <asio/ip/tcp.hpp>
+
+namespace socks4 {
+
+const unsigned char version = 0x04;
+
+class request
+{
+public:
+  enum command_type
+  {
+    connect = 0x01,
+    bind = 0x02
+  };
+
+  request(command_type cmd, const asio::ip::tcp::endpoint& endpoint,
+      const std::string& user_id)
+    : version_(version),
+      command_(cmd),
+      user_id_(user_id),
+      null_byte_(0)
+  {
+    // Only IPv4 is supported by the SOCKS 4 protocol.
+    if (endpoint.protocol() != asio::ip::tcp::v4())
+    {
+      throw asio::system_error(
+          asio::error::address_family_not_supported);
+    }
+
+    // Convert port number to network byte order.
+    unsigned short port = endpoint.port();
+    port_high_byte_ = (port >> 8) & 0xff;
+    port_low_byte_ = port & 0xff;
+
+    // Save IP address in network byte order.
+    address_ = endpoint.address().to_v4().to_bytes();
+  }
+
+  std::array<asio::const_buffer, 7> buffers() const
+  {
+    return
+    {
+      {
+        asio::buffer(&version_, 1),
+        asio::buffer(&command_, 1),
+        asio::buffer(&port_high_byte_, 1),
+        asio::buffer(&port_low_byte_, 1),
+        asio::buffer(address_),
+        asio::buffer(user_id_),
+        asio::buffer(&null_byte_, 1)
+      }
+    };
+  }
+
+private:
+  unsigned char version_;
+  unsigned char command_;
+  unsigned char port_high_byte_;
+  unsigned char port_low_byte_;
+  asio::ip::address_v4::bytes_type address_;
+  std::string user_id_;
+  unsigned char null_byte_;
+};
+
+class reply
+{
+public:
+  enum status_type
+  {
+    request_granted = 0x5a,
+    request_failed = 0x5b,
+    request_failed_no_identd = 0x5c,
+    request_failed_bad_user_id = 0x5d
+  };
+
+  reply()
+    : null_byte_(0),
+      status_()
+  {
+  }
+
+  std::array<asio::mutable_buffer, 5> buffers()
+  {
+    return
+    {
+      {
+        asio::buffer(&null_byte_, 1),
+        asio::buffer(&status_, 1),
+        asio::buffer(&port_high_byte_, 1),
+        asio::buffer(&port_low_byte_, 1),
+        asio::buffer(address_)
+      }
+    };
+  }
+
+  bool success() const
+  {
+    return null_byte_ == 0 && status_ == request_granted;
+  }
+
+  unsigned char status() const
+  {
+    return status_;
+  }
+
+  asio::ip::tcp::endpoint endpoint() const
+  {
+    unsigned short port = port_high_byte_;
+    port = (port << 8) & 0xff00;
+    port = port | port_low_byte_;
+
+    asio::ip::address_v4 address(address_);
+
+    return asio::ip::tcp::endpoint(address, port);
+  }
+
+private:
+  unsigned char null_byte_;
+  unsigned char status_;
+  unsigned char port_high_byte_;
+  unsigned char port_low_byte_;
+  asio::ip::address_v4::bytes_type address_;
+};
+
+} // namespace socks4
+
+#endif // SOCKS4_HPP

asio/src/examples/cpp11/socks4/sync_client.cpp

@@ -0,0 +1,93 @@
+//
+// sync_client.cpp
+// ~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <array>
+#include <iostream>
+#include <iomanip>
+#include <ostream>
+#include <string>
+#include <asio.hpp>
+#include "socks4.hpp"
+
+using asio::ip::tcp;
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 4)
+    {
+      std::cout << "Usage: sync_client <socks4server> <socks4port> <user>\n";
+      std::cout << "Examples:\n";
+      std::cout << "  sync_client 127.0.0.1 1080 chris\n";
+      std::cout << "  sync_client localhost socks chris\n";
+      return 1;
+    }
+
+    asio::io_context io_context;
+
+    // Get a list of endpoints corresponding to the SOCKS 4 server name.
+    tcp::resolver resolver(io_context);
+    auto endpoints = resolver.resolve(argv[1], argv[2]);
+
+    // Try each endpoint until we successfully establish a connection to the
+    // SOCKS 4 server.
+    tcp::socket socket(io_context);
+    asio::connect(socket, endpoints);
+
+    // Get an endpoint for the Boost website. This will be passed to the SOCKS
+    // 4 server. Explicitly specify IPv4 since SOCKS 4 does not support IPv6.
+    auto http_endpoint = *resolver.resolve(tcp::v4(), "www.boost.org", "http");
+
+    // Send the request to the SOCKS 4 server.
+    socks4::request socks_request(
+        socks4::request::connect, http_endpoint, argv[3]);
+    asio::write(socket, socks_request.buffers());
+
+    // Receive a response from the SOCKS 4 server.
+    socks4::reply socks_reply;
+    asio::read(socket, socks_reply.buffers());
+
+    // Check whether we successfully negotiated with the SOCKS 4 server.
+    if (!socks_reply.success())
+    {
+      std::cout << "Connection failed.\n";
+      std::cout << "status = 0x" << std::hex << socks_reply.status();
+      return 1;
+    }
+
+    // Form the HTTP request. We specify the "Connection: close" header so that
+    // the server will close the socket after transmitting the response. This
+    // will allow us to treat all data up until the EOF as the response.
+    std::string request =
+      "GET / HTTP/1.0\r\n"
+      "Host: www.boost.org\r\n"
+      "Accept: */*\r\n"
+      "Connection: close\r\n\r\n";
+
+    // Send the HTTP request.
+    asio::write(socket, asio::buffer(request));
+
+    // Read until EOF, writing data to output as we go.
+    std::array<char, 512> response;
+    std::error_code error;
+    while (std::size_t s = socket.read_some(
+          asio::buffer(response), error))
+      std::cout.write(response.data(), s);
+    if (error != asio::error::eof)
+      throw std::system_error(error);
+  }
+  catch (std::exception& e)
+  {
+    std::cout << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}