separate anonymous mode and force-proxy mode, and tighten it up a bit

ChangeLog

@@ -1,3 +1,4 @@
+	* separate anonymous mode and force-proxy mode, and tighten it up a bit
 	* add per-tracker scrape information to announce_entry
 	* report errors in read_piece_alert
 	* DHT memory optimization

docs/manual.rst

@@ -4592,6 +4592,7 @@ session_settings
 		bool ignore_resume_timestamps;
 		bool no_recheck_incomplete_resume;
 		bool anonymous_mode;
+		bool force_proxy;
 		int tick_interval;
 		int share_mode_target;
 
@@ -5339,14 +5340,17 @@ mode.
 ``anonymous_mode`` defaults to false. When set to true, the client tries
 to hide its identity to a certain degree. The peer-ID will no longer
 include the client's fingerprint. The user-agent will be reset to an
-empty string. Trackers will only be used if they are using a proxy
-server. The listen sockets are closed, and incoming connections will
-only be accepted through a SOCKS5 or I2P proxy (if a peer proxy is set up and
-is run on the same machine as the tracker proxy). Since no incoming connections
-are accepted, NAT-PMP, UPnP, DHT and local peer discovery are all turned off
-when this setting is enabled.
+empty string.
 
-If you're using I2P, it might make sense to enable anonymous mode as well.
+If you're using I2P, it might make sense to enable anonymous mode.
+
+``force_proxy`` disables any communication that's not going over a proxy.
+Enabling this requires a proxy to be configured as well, see ``set_proxy_settings``.
+The listen sockets are closed, and incoming connections will
+only be accepted through a SOCKS5 or I2P proxy (if a peer proxy is set up and
+is run on the same machine as the tracker proxy). This setting also
+disabled peer country lookups, since those are done via DNS lookups that
+aren't supported by proxies.
 
 ``tick_interval`` specifies the number of milliseconds between internal
 ticks. This is the frequency with which bandwidth quota is distributed to

include/libtorrent/session_settings.hpp

@@ -758,12 +758,20 @@ namespace libtorrent
 		bool no_recheck_incomplete_resume;
 
 		// when this is true, libtorrent will take actions to make sure no
-		// privacy sensitive information is leaked out from the client. This
-		// mode is assumed to be combined with using a proxy for all your
-		// traffic. With this option, your true IP address will not be exposed
-		// nor anything that can tie your connection to your true IP
+		// privacy sensitive information is leaked out from the client.
+		// With this option, your IP address will not be exposed over
+		// the wire protocol. Other measures will also be taken to make it
+		// harder to track you.
 		bool anonymous_mode;
 
+		// when this is true, no connection will ever be made without going
+		// through a proxy. If you set up a proxy and prefer connections not
+		// supported by the proxy to fail, rather than circumventing it, set
+		// this to true. For instance, reverse DNS lookups can rarely be
+		// made via a proxy, so resolving peer countries is disabled with
+		// this switch.
+		bool force_proxy;
+
 		// the number of milliseconds between internal ticks. Should be no
 		// more than one second (i.e. 1000).
 		int tick_interval;

include/libtorrent/torrent.hpp

@@ -347,7 +347,7 @@ namespace libtorrent
 
 		bool resolving_countries() const
 		{
-			return m_resolve_countries && !m_ses.settings().anonymous_mode;
+			return m_resolve_countries && !m_ses.settings().force_proxy;
 		}
 #endif
 

include/libtorrent/udp_socket.hpp

@@ -96,6 +96,7 @@ namespace libtorrent
 
 		void set_proxy_settings(proxy_settings const& ps);
 		proxy_settings const& get_proxy_settings() { return m_proxy_settings; }
+		void set_force_proxy(bool f) { m_force_proxy = f; }
 
 		bool is_closed() const { return m_abort; }
 		tcp::endpoint local_endpoint(error_code& ec) const
@@ -235,6 +236,7 @@ namespace libtorrent
 		char m_tmp_buf[270];
 		bool m_queue_packets;
 		bool m_tunnel_packets;
+		bool m_force_proxy;
 		bool m_abort;
 		udp::endpoint m_proxy_addr;
 		// while we're connecting to the proxy

src/session.cpp

@@ -1247,7 +1247,8 @@ namespace libtorrent
 		, max_pex_peers(50)
 		, ignore_resume_timestamps(false)
 		, no_recheck_incomplete_resume(false)
-		, anonymous_mode(false)
+		, anonymous_mode(true)
+		, force_proxy(false)
 		, tick_interval(100)
 		, report_web_seed_downloads(true)
 		, share_mode_target(3)

src/session_impl.cpp

@@ -410,6 +410,7 @@ namespace aux {
 		TORRENT_SETTING(boolean, ignore_resume_timestamps)
 		TORRENT_SETTING(boolean, no_recheck_incomplete_resume)
 		TORRENT_SETTING(boolean, anonymous_mode)
+		TORRENT_SETTING(boolean, force_proxy)
 		TORRENT_SETTING(integer, tick_interval)
 		TORRENT_SETTING(boolean, report_web_seed_downloads)
 		TORRENT_SETTING(integer, share_mode_target)
@@ -2024,9 +2025,6 @@ namespace aux {
 			|| m_settings.active_limit != s.active_limit))
 			m_auto_manage_time_scaler = 2;
 
-		// if anonymous mode was enabled, clear out the peer ID
-		bool anonymous = (m_settings.anonymous_mode != s.anonymous_mode && s.anonymous_mode);
-
 		if (m_settings.report_web_seed_downloads != s.report_web_seed_downloads)
 		{
 			// if this flag changed, update all web seed connections
@@ -2065,9 +2063,13 @@ namespace aux {
 		if (connections_limit_changed) update_connections_limit();
 		if (unchoke_limit_changed) update_unchoke_limit();
 	
-		// enable anonymous mode. We don't want to accept any incoming
+		bool force_proxy = (m_settings.force_proxy != s.force_proxy && s.force_proxy);
+
+		m_udp_socket.set_force_proxy(s.force_proxy);
+
+		// in force_proxy mode, we don't want to accept any incoming
 		// connections, except through a proxy.
-		if (anonymous)
+		if (force_proxy)
 		{
 			m_settings.user_agent.clear();
 			url_random((char*)&m_peer_id[0], (char*)&m_peer_id[0] + 20);
@@ -5368,10 +5370,10 @@ retry:
 		if (m_socks_listen_socket && m_socks_listen_socket->is_open())
 			return m_socks_listen_port;
 
-		// if not, don't tell the tracker anything if we're in anonymous
+		// if not, don't tell the tracker anything if we're in force_proxy
 		// mode. We don't want to leak our listen port since it can
 		// potentially identify us if it is leaked elsewere
-		if (m_settings.anonymous_mode) return 0;
+		if (m_settings.force_proxy) return 0;
 		if (m_listen_sockets.empty()) return 0;
 		return m_listen_sockets.front().external_port;
 	}
@@ -5386,10 +5388,10 @@ retry:
 			&& m_proxy.hostname == m_proxy.hostname)
 			return m_socks_listen_port;
 
-		// if not, don't tell the tracker anything if we're in anonymous
+		// if not, don't tell the tracker anything if we're in force_proxy
 		// mode. We don't want to leak our listen port since it can
 		// potentially identify us if it is leaked elsewere
-		if (m_settings.anonymous_mode) return 0;
+		if (m_settings.force_proxy) return 0;
 		if (m_listen_sockets.empty()) return 0;
 		for (std::list<listen_socket_t>::const_iterator i = m_listen_sockets.begin()
 			, end(m_listen_sockets.end()); i != end; ++i)

src/torrent.cpp

@@ -2406,10 +2406,10 @@ namespace libtorrent
 			if (!is_any(bind_interface)) req.bind_ip = bind_interface;
 			else req.bind_ip = m_ses.m_listen_interface.address();
 
-			if (settings().anonymous_mode)
+			if (settings().force_proxy)
 			{
-				// in anonymous_mode we don't talk directly to trackers
-				// only if there is a proxy
+				// in force_proxy mode we don't talk directly to trackers
+				// unless there is a proxy
 				std::string protocol = req.url.substr(0, req.url.find(':'));
 				int proxy_type = m_ses.m_proxy.type;
 	

src/udp_socket.cpp

@@ -73,6 +73,7 @@ udp_socket::udp_socket(asio::io_service& ios
 	, m_resolver(ios)
 	, m_queue_packets(false)
 	, m_tunnel_packets(false)
+	, m_force_proxy(false)
 	, m_abort(false)
 	, m_outstanding_ops(0)
 #if TORRENT_USE_IPV6
@@ -143,6 +144,10 @@ void udp_socket::send_hostname(char const* hostname, int port
 		wrap(hostname, port, p, len, ec);
 		return;	
 	}
+	else if (m_force_proxy)
+	{
+		return;
+	}
 
 	// this function is only supported when we're using a proxy
 	TORRENT_ASSERT(m_queue_packets);
@@ -175,6 +180,10 @@ void udp_socket::send(udp::endpoint const& ep, char const* p, int len
 			wrap(ep, p, len, ec);
 			return;	
 		}
+		else if (m_force_proxy)
+		{
+			return;
+		}
 
 		if (m_queue_packets)
 		{
@@ -187,6 +196,10 @@ void udp_socket::send(udp::endpoint const& ep, char const* p, int len
 			return;
 		}
 	}
+	else if (m_force_proxy)
+	{
+		return;
+	}
 
 #if TORRENT_USE_IPV6
 	if (ep.address().is_v6() && m_ipv6_sock.is_open())
@@ -430,7 +443,7 @@ void udp_socket::on_read_impl(udp::socket* s, udp::endpoint const& ep
 			if (ep == m_proxy_addr)
 				unwrap(e, m_buf, bytes_transferred);
 		}
-		else
+		else if (!m_force_proxy) // block incoming packets that aren't coming via the proxy
 		{
 			call_handler(e, ep, m_buf, bytes_transferred);
 		}