From 9bfb108b4f6502b3f2697ca8676be93c11067a9b Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@cs.umu.se>
Date: Thu, 5 Mar 2020 11:46:04 +0100
Subject: [PATCH] enable all disabled trackers when listen sockets are
 re-opened

---
 include/libtorrent/torrent.hpp |  4 ++++
 src/session_impl.cpp           | 10 ++++++++++
 src/torrent.cpp                |  7 +++++++
 3 files changed, 21 insertions(+)

diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index 0f2d99af6..794454878 100644
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -1011,6 +1011,10 @@ namespace libtorrent {
 		std::vector<announce_entry> const& trackers() const
 		{ return m_trackers; }
 
+		// this sets all the "enabled" states on all trackers, giving them
+		// all one more chance of being tried
+		void enable_all_trackers();
+
 		void replace_trackers(std::vector<announce_entry> const& urls);
 
 		// returns true if the tracker was added, and false if it was already
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 93ab99a94..0f966d143 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -2027,6 +2027,16 @@ namespace aux {
 #if TORRENT_USE_I2P
 		open_new_incoming_i2p_connection();
 #endif
+
+		// trackers that were not reachable, may have become reachable now.
+		// so clear the "disabled" flags to let them be tried one more time
+		// TODO: it would probably be better to do this by having a
+		// listen-socket "version" number that gets bumped. And instead of
+		// setting a bool to disable a tracker, we set the version number that
+		// it was disabled at. This change would affect the ABI in 1.2, so
+		// should be done in 2.0 or later
+		for (auto& t : m_torrents)
+			t.second->enable_all_trackers();
 	}
 
 	void session_impl::reopen_network_sockets(reopen_network_flags_t const options)
diff --git a/src/torrent.cpp b/src/torrent.cpp
index d75f11798..7fc205e24 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -6201,6 +6201,13 @@ bool is_downloading_state(int const st)
 		return m_torrent_file;
 	}
 
+	void torrent::enable_all_trackers()
+	{
+		for (announce_entry& ae : m_trackers)
+			for (announce_endpoint& aep : ae.endpoints)
+				aep.enabled = true;
+	}
+
 	void torrent::write_resume_data(add_torrent_params& ret) const
 	{
 		ret.version = LIBTORRENT_VERSION_NUM;