some socks5 cleanup

include/libtorrent/socks5_stream.hpp

@@ -37,6 +37,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <boost/shared_ptr.hpp>
 
 #include "libtorrent/proxy_base.hpp"
+#include "libtorrent/assert.hpp"
 #if defined TORRENT_ASIO_DEBUGGING
 #include "libtorrent/debug.hpp"
 #endif
@@ -73,16 +74,27 @@ class socks5_stream : public proxy_base
 {
 public:
 
+	// commands
+	enum {
+		socks5_connect = 1,
+		socks5_bind = 2,
+		socks5_udp_associate = 3
+	};
+
 	explicit socks5_stream(io_service& io_service)
 		: proxy_base(io_service)
 		, m_version(5)
-		, m_command(1)
+		, m_command(socks5_connect)
 		, m_listen(0)
 	{}
 
 	void set_version(int v) { m_version = v; }
 
-	void set_command(int c) { m_command = c; }
+	void set_command(int c)
+	{
+		TORRENT_ASSERT(c >= socks5_connect && c <=socks5_udp_associate);
+		m_command = c;
+	}
 
 	void set_username(std::string const& user
 		, std::string const& password)
@@ -114,11 +126,17 @@ public:
 	}
 #endif
 
-//#error fix error messages to use custom error_code category
+	// TODO: 2 fix error messages to use custom error_code category
-//#error add async_connect() that takes a hostname and port as well
+	// TODO: 2 add async_connect() that takes a hostname and port as well
 	template <class Handler>
 	void async_connect(endpoint_type const& endpoint, Handler const& handler)
 	{
+		// make sure we don't try to connect to INADDR_ANY. binding is fine,
+		// and using a hostname is fine on SOCKS version 5.
+		TORRENT_ASSERT(m_command == socks5_bind
+			|| endpoint.address() != address()
+			|| (!m_dst_name.empty() && m_version == 5));
+
 		m_remote_endpoint = endpoint;
 
 		// the connect is split up in the following steps:
@@ -163,7 +181,11 @@ private:
 	std::string m_password;
 	std::string m_dst_name;
 	int m_version;
+
+	// the socks command to send for this connection (connect, bind,
+	// udp associate)
 	int m_command;
+
 	// set to one when we're waiting for the
 	// second message to accept an incoming connection
 	int m_listen;

src/socks5_stream.cpp

@@ -294,6 +294,10 @@ namespace libtorrent
 			}
 			else
 			{
+				// we either need a hostname or a valid endpoint
+				TORRENT_ASSERT(m_command == socks5_bind
+					|| m_remote_endpoint.address() != address());
+
 				write_uint8(m_remote_endpoint.address().is_v4()?1:4, p); // address type
 				write_address(m_remote_endpoint.address(), p);
 			}
@@ -398,7 +402,7 @@ namespace libtorrent
 			// we ignore the proxy IP it was bound to
 			if (atyp == 1)
 			{
-				if (m_command == 2)
+				if (m_command == socks5_bind)
 				{
 					if (m_listen == 0)
 					{
@@ -459,7 +463,7 @@ namespace libtorrent
 			// access granted
 			if (response == 90)
 			{
-				if (m_command == 2)
+				if (m_command == socks5_bind)
 				{
 					if (m_listen == 0)
 					{
@@ -505,7 +509,7 @@ namespace libtorrent
 
 		if (handle_error(e, h)) return;
 
-		if (m_command == 2)
+		if (m_command == socks5_bind)
 		{
 			if (m_listen == 0)
 			{