[SOCKS] wrap DNS type requests response as IPv4 (fixes netcat usage, closes #1336)

Signed-off-by: R4SAS <r4sas@i2pmail.org>

libi2pd_client/SOCKS.cpp

@@ -246,6 +246,9 @@ namespace proxy
 				size = 7 + addr.dns.size;
 				m_response[4] = addr.dns.size;
 				memcpy(m_response + 5, addr.dns.value, addr.dns.size);
+				// replace type to IPv4 for support socks5 clients
+				// without domain name resolving support (like netcat)
+				m_response[3] = ADDR_IPV4;
 				break;
 		}
 		htobe16buf(m_response + size - 2, port); //Port
@@ -291,15 +294,13 @@ namespace proxy
 		if (m_authchosen == AUTH_UNACCEPTABLE)
 		{
 			LogPrint(eLogWarning, "SOCKS: v5 authentication negotiation failed");
-			boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksFailed,
+			boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksFailed, shared_from_this(), std::placeholders::_1));
-												shared_from_this(), std::placeholders::_1));
 			return false;
 		}
 		else
 		{
 			LogPrint(eLogDebug, "SOCKS: v5 choosing authentication method: ", m_authchosen);
-			boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksResponse,
+			boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksResponse, shared_from_this(), std::placeholders::_1));
-												shared_from_this(), std::placeholders::_1));
 			return true;
 		}
 	}
@@ -343,8 +344,7 @@ namespace proxy
 				response = GenerateSOCKS5Response(SOCKS5_OK, ADDR_DNS, ad, m_stream->GetRecvStreamID());
 			break;
 		}
-		boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksDone,
+		boost::asio::async_write(*m_sock, response, std::bind(&SOCKSHandler::SentSocksDone, shared_from_this(), std::placeholders::_1));
-											shared_from_this(), std::placeholders::_1));
 	}
 
 	void SOCKSHandler::EnterState(SOCKSHandler::state nstate, uint8_t parseleft) {
@@ -735,8 +735,7 @@ namespace proxy
 		LogPrint(eLogInfo, "SOCKS: negotiating with upstream proxy");
 		EnterState(UPSTREAM_HANDSHAKE);
 		if (m_upstreamSock) {
-			boost::asio::write(*m_upstreamSock,
+			boost::asio::write(*m_upstreamSock, GenerateUpstreamRequest());
-												 GenerateUpstreamRequest());
 			AsyncUpstreamSockRead();
 		} else {
 			LogPrint(eLogError, "SOCKS: no upstream socket to send handshake to");