From 2a703e08446616bc1f04b9e5a29eb1714b318c16 Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Wed, 26 Oct 2022 16:05:40 -0400
Subject: [PATCH] SSU2 through a socks5 proxy

---
 libi2pd/Config.cpp     |  1 +
 libi2pd/SSU2.cpp       | 50 +++++++++++++++++++++++++++++++++++++++---
 libi2pd/SSU2.h         |  1 +
 libi2pd/Transports.cpp | 18 ++++++++++++++-
 4 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/libi2pd/Config.cpp b/libi2pd/Config.cpp
index 2a9955c2..94609101 100644
--- a/libi2pd/Config.cpp
+++ b/libi2pd/Config.cpp
@@ -277,6 +277,7 @@ namespace config {
 			("ssu2.enabled", value<bool>()->default_value(true),         "Enable SSU2 (default: enabled)")
 			("ssu2.published", value<bool>()->default_value(true),        "Publish SSU2 (default: enabled)")
 			("ssu2.port", value<uint16_t>()->default_value(0),            "Port to listen for incoming SSU2 packets (default: auto)")
+			("ssu2.proxy", value<std::string>()->default_value(""),       "Socks5 proxy URL for SSU2 transport")
 		;
 
 		options_description nettime("Time sync options");
diff --git a/libi2pd/SSU2.cpp b/libi2pd/SSU2.cpp
index c323002c..7f6fbd42 100644
--- a/libi2pd/SSU2.cpp
+++ b/libi2pd/SSU2.cpp
@@ -42,6 +42,11 @@ namespace transport
 				if (!address) continue;
 				if (address->transportStyle == i2p::data::RouterInfo::eTransportSSU2)
 				{
+					if (m_IsThroughProxy)
+					{
+						found = true;
+						break; // we don't need port for proxy
+					}	
 					auto port = address->port;
 					if (!port)
 					{
@@ -84,7 +89,11 @@ namespace transport
 				}
 			}
 			if (found)
+			{	
 				m_ReceiveService.Start ();
+				if (m_IsThroughProxy)
+					ConnectToProxy ();
+			}	
 			ScheduleTermination ();
 			ScheduleResend (false);
 		}
@@ -257,7 +266,10 @@ namespace transport
 	{
 		if (packet)
 		{
-			ProcessNextPacket (packet->buf, packet->len, packet->from);
+			if (m_IsThroughProxy)
+				ProcessNextPacketFromProxy (packet->buf, packet->len);
+			else	
+				ProcessNextPacket (packet->buf, packet->len, packet->from);
 			m_PacketsPool.ReleaseMt (packet);
 			if (m_LastSession && m_LastSession->GetState () != eSSU2SessionStateTerminated)
 				m_LastSession->FlushData ();
@@ -266,8 +278,12 @@ namespace transport
 
 	void SSU2Server::HandleReceivedPackets (std::vector<Packet *> packets)
 	{
-		for (auto& packet: packets)
-			ProcessNextPacket (packet->buf, packet->len, packet->from);
+		if (m_IsThroughProxy)
+			for (auto& packet: packets)
+				ProcessNextPacketFromProxy (packet->buf, packet->len);
+		else	
+			for (auto& packet: packets)
+				ProcessNextPacket (packet->buf, packet->len, packet->from);
 		m_PacketsPool.ReleaseMt (packets);
 		if (m_LastSession && m_LastSession->GetState () != eSSU2SessionStateTerminated)
 			m_LastSession->FlushData ();
@@ -479,6 +495,11 @@ namespace transport
 	void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * payload, size_t payloadLen,
 		const boost::asio::ip::udp::endpoint& to)
 	{
+		if (m_IsThroughProxy)
+		{
+			SendThroughProxy (header, headerLen, nullptr, 0, payload, payloadLen, to);
+			return;
+		}	
 		std::vector<boost::asio::const_buffer> bufs
 		{
 			boost::asio::buffer (header, headerLen),
@@ -498,6 +519,11 @@ namespace transport
 	void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen,
 		const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to)
 	{
+		if (m_IsThroughProxy)
+		{
+			SendThroughProxy (header, headerLen, headerX, headerXLen, payload, payloadLen, to);
+			return;
+		}
 		std::vector<boost::asio::const_buffer> bufs
 		{
 			boost::asio::buffer (header, headerLen),
@@ -1250,5 +1276,23 @@ namespace transport
 					ReadUDPAssociateSocket ();
 			});	
 	}	
+
+	bool SSU2Server::SetProxy (const std::string& address, uint16_t port)
+	{
+		boost::system::error_code ecode;
+		auto addr = boost::asio::ip::address::from_string (address, ecode);
+		if (!ecode && !addr.is_unspecified () && port)
+		{
+			m_IsThroughProxy = true;
+			m_ProxyEndpoint.reset (new boost::asio::ip::tcp::endpoint (addr, port));
+		}	
+		else
+		{
+			if (ecode)
+				LogPrint (eLogError, "SSU2: Invalid proxy address ", address, " ", ecode.message());
+			return false;
+		}	
+		return true;
+	}	
 }
 }
diff --git a/libi2pd/SSU2.h b/libi2pd/SSU2.h
index 6eff7109..767a9eb8 100644
--- a/libi2pd/SSU2.h
+++ b/libi2pd/SSU2.h
@@ -57,6 +57,7 @@ namespace transport
 			void Stop ();
 			boost::asio::io_service& GetService () { return GetIOService (); };
 			void SetLocalAddress (const boost::asio::ip::address& localAddress);
+			bool SetProxy (const std::string& address, uint16_t port);
 			bool IsSupported (const boost::asio::ip::address& addr) const;
 			uint16_t GetPort (bool v4) const;
 			bool IsSyncClockFromPeers () const { return m_IsSyncClockFromPeers; };
diff --git a/libi2pd/Transports.cpp b/libi2pd/Transports.cpp
index 6dac23de..04ded36f 100644
--- a/libi2pd/Transports.cpp
+++ b/libi2pd/Transports.cpp
@@ -218,7 +218,23 @@ namespace transport
 			}
 		}
 		// create SSU2 server
-		if (enableSSU2) m_SSU2Server = new SSU2Server ();
+		if (enableSSU2) 
+		{	
+			m_SSU2Server = new SSU2Server ();
+			std::string ssu2proxy; i2p::config::GetOption("ssu2.proxy", ssu2proxy);
+			if (!ssu2proxy.empty())
+			{
+				if (proxyurl.parse (ssu2proxy) && proxyurl.schema == "socks")
+				{
+					if (m_SSU2Server->SetProxy (proxyurl.host, proxyurl.port))
+						i2p::context.SetStatus (eRouterStatusProxy);
+					else
+						LogPrint(eLogError, "Transports: Can't set SSU2 proxy ", ssu2proxy);
+				}	
+				else
+					LogPrint(eLogError, "Transports: Invalid SSU2 proxy URL ", ssu2proxy);
+			}	
+		}	
 
 		// bind to interfaces
 		bool ipv4; i2p::config::GetOption("ipv4", ipv4);