From 571952fd192fa9811e8df34cb1f1e36b8a453cbf Mon Sep 17 00:00:00 2001
From: arvidn <arvid@libtorrent.org>
Date: Mon, 13 Jan 2020 19:18:18 +0100
Subject: [PATCH] bind SOCKS5 connection to correct outgoing interface

---
 bindings/python/src/alert.cpp     |  2 ++
 include/libtorrent/operations.hpp |  3 +++
 src/alert.cpp                     |  4 +++-
 src/udp_socket.cpp                | 24 ++++++++++++++++++++++++
 4 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/bindings/python/src/alert.cpp b/bindings/python/src/alert.cpp
index 2809229de..64ae05839 100644
--- a/bindings/python/src/alert.cpp
+++ b/bindings/python/src/alert.cpp
@@ -370,6 +370,8 @@ void bind_alert()
        .value("partfile_write", operation_t::partfile_write)
        .value("hostname_lookup", operation_t::hostname_lookup)
        .value("symlink", operation_t::symlink)
+       .value("handshake", operation_t::handshake)
+       .value("sock_option", operation_t::sock_option)
        ;
 
     def("operation_name", static_cast<char const*(*)(operation_t)>(&lt::operation_name));
diff --git a/include/libtorrent/operations.hpp b/include/libtorrent/operations.hpp
index 220c9957e..4847184e1 100644
--- a/include/libtorrent/operations.hpp
+++ b/include/libtorrent/operations.hpp
@@ -169,6 +169,9 @@ namespace libtorrent {
 
 		// handshake with a peer or server
 		handshake,
+
+		// set socket option
+		sock_option,
 	};
 
 	// maps an operation id (from peer_error_alert and peer_disconnected_alert)
diff --git a/src/alert.cpp b/src/alert.cpp
index a90e9165b..d5cd080b1 100644
--- a/src/alert.cpp
+++ b/src/alert.cpp
@@ -896,6 +896,7 @@ namespace {
 			case o::hostname_lookup: return -1;
 			case o::symlink: return -1;
 			case o::handshake: return -1;
+			case o::sock_option: return -1;
 		}
 		return -1;
 	}
@@ -1562,7 +1563,8 @@ namespace {
 			"partfile_write",
 			"hostname_lookup",
 			"symlink",
-			"handshake"
+			"handshake",
+			"sock_option"
 		};
 
 		int const idx = static_cast<int>(op);
diff --git a/src/udp_socket.cpp b/src/udp_socket.cpp
index 685d74660..bf61db858 100644
--- a/src/udp_socket.cpp
+++ b/src/udp_socket.cpp
@@ -556,9 +556,33 @@ void socks5::on_name_lookup(error_code const& e, tcp::resolver::iterator i)
 
 	error_code ec;
 	m_socks5_sock.open(is_v4(m_proxy_addr) ? tcp::v4() : tcp::v6(), ec);
+	if (ec)
+	{
+		if (m_alerts.should_post<socks5_alert>())
+			m_alerts.emplace_alert<socks5_alert>(m_proxy_addr, operation_t::sock_open, ec);
+		return;
+	}
 
 	// enable keepalives
 	m_socks5_sock.set_option(boost::asio::socket_base::keep_alive(true), ec);
+	if (ec)
+	{
+		if (m_alerts.should_post<socks5_alert>())
+			m_alerts.emplace_alert<socks5_alert>(m_proxy_addr, operation_t::sock_option, ec);
+		return;
+	}
+
+	tcp::endpoint const bind_ep(m_listen_socket.get_local_endpoint().address(), 0);
+	m_socks5_sock.bind(bind_ep, ec);
+	if (ec)
+	{
+		if (m_alerts.should_post<socks5_alert>())
+			m_alerts.emplace_alert<socks5_alert>(m_proxy_addr, operation_t::sock_bind, ec);
+		return;
+	}
+
+	// TODO: perhaps an attempt should be made to bind m_socks5_sock to the
+	// device of m_listen_socket
 
 	ADD_OUTSTANDING_ASYNC("socks5::on_connected");
 	m_socks5_sock.async_connect(m_proxy_addr