Remove settings to exchange trackers. It wasn't used by non-libtorrent clients. Also it has a privacy risk and you might be DDoSing someone. DHT makes it obsolete anyway.

src/base/bittorrent/session.cpp

@@ -55,7 +55,6 @@
 #include <libtorrent/bencode.hpp>
 #include <libtorrent/error_code.hpp>
 #include <libtorrent/extensions/ut_metadata.hpp>
-#include <libtorrent/extensions/lt_trackers.hpp>
 #include <libtorrent/extensions/ut_pex.hpp>
 #include <libtorrent/extensions/smart_ban.hpp>
 #include <libtorrent/identify_client.hpp>
@@ -213,7 +212,6 @@ Session::Session(QObject *parent)
     , m_isDHTEnabled(BITTORRENT_SESSION_KEY("DHTEnabled"), true)
     , m_isLSDEnabled(BITTORRENT_SESSION_KEY("LSDEnabled"), true)
     , m_isPeXEnabled(BITTORRENT_SESSION_KEY("PeXEnabled"), true)
-    , m_isTrackerExchangeEnabled(BITTORRENT_SESSION_KEY("TrackerExchangeEnabled"), false)
     , m_isIPFilteringEnabled(BITTORRENT_SESSION_KEY("IPFilteringEnabled"), false)
     , m_isTrackerFilteringEnabled(BITTORRENT_SESSION_KEY("TrackerFilteringEnabled"), false)
     , m_IPFilterFile(BITTORRENT_SESSION_KEY("IPFilter"))
@@ -278,7 +276,6 @@ Session::Session(QObject *parent)
     , m_isTrackerEnabled(BITTORRENT_KEY("TrackerEnabled"), false)
     , m_bannedIPs("State/BannedIPs")
     , m_wasPexEnabled(m_isPeXEnabled)
-    , m_wasTrackerExchangeEnabled(m_isTrackerExchangeEnabled)
     , m_numResumeData(0)
     , m_extraLimit(0)
     , m_useProxy(false)
@@ -365,8 +362,6 @@ Session::Session(QObject *parent)
     // Enabling plugins
     //m_nativeSession->add_extension(&libt::create_metadata_plugin);
     m_nativeSession->add_extension(&libt::create_ut_metadata_plugin);
-    if (isTrackerExchangeEnabled())
-        m_nativeSession->add_extension(&libt::create_lt_trackers_plugin);
     if (isPeXEnabled())
         m_nativeSession->add_extension(&libt::create_ut_pex_plugin);
     m_nativeSession->add_extension(&libt::create_smart_ban_plugin);
@@ -475,18 +470,6 @@ void Session::setPeXEnabled(bool enabled)
         Logger::instance()->addMessage(tr("Restart is required to toggle PeX support"), Log::WARNING);
 }
 
-bool Session::isTrackerExchangeEnabled() const
-{
-    return m_isTrackerExchangeEnabled;
-}
-
-void Session::setTrackerExchangeEnabled(bool enabled)
-{
-    m_isTrackerExchangeEnabled = enabled;
-    if (m_wasTrackerExchangeEnabled != enabled)
-        Logger::instance()->addMessage(tr("Restart is required to toggle Tracker Exchange support"), Log::WARNING);
-}
-
 bool Session::isTempPathEnabled() const
 {
     return m_isTempPathEnabled;

src/base/bittorrent/session.h

@@ -218,8 +218,6 @@ namespace BitTorrent
         void setLSDEnabled(bool enabled);
         bool isPeXEnabled() const;
         void setPeXEnabled(bool enabled);
-        bool isTrackerExchangeEnabled() const;
-        void setTrackerExchangeEnabled(bool enabled);
         bool isAddTorrentPaused() const;
         void setAddTorrentPaused(bool value);
         bool isTrackerEnabled() const;
@@ -507,7 +505,6 @@ namespace BitTorrent
         CachedSettingValue<bool> m_isDHTEnabled;
         CachedSettingValue<bool> m_isLSDEnabled;
         CachedSettingValue<bool> m_isPeXEnabled;
-        CachedSettingValue<bool> m_isTrackerExchangeEnabled;
         CachedSettingValue<bool> m_isIPFilteringEnabled;
         CachedSettingValue<bool> m_isTrackerFilteringEnabled;
         CachedSettingValue<QString> m_IPFilterFile;
@@ -572,11 +569,10 @@ namespace BitTorrent
         CachedSettingValue<bool> m_isTrackerEnabled;
         CachedSettingValue<QStringList> m_bannedIPs;
 
-        // Order is important. These need to be declared after their CachedSettingsValue
+        // Order is important. This needs to be declared after its CachedSettingsValue
-        // counterparts, because they use them for initialization in the constructor
+        // counterpart, because it uses it for initialization in the constructor
         // initialization list.
         const bool m_wasPexEnabled;
-        const bool m_wasTrackerExchangeEnabled;
 
         int m_numResumeData;
         int m_extraLimit;

src/base/settingsstorage.cpp

@@ -127,7 +127,6 @@ namespace
             {"BitTorrent/Session/DHTEnabled", "Preferences/Bittorrent/DHT"},
             {"BitTorrent/Session/LSDEnabled", "Preferences/Bittorrent/LSD"},
             {"BitTorrent/Session/PeXEnabled", "Preferences/Bittorrent/PeX"},
-            {"BitTorrent/Session/TrackerExchangeEnabled", "Preferences/Advanced/LtTrackerExchange"},
             {"BitTorrent/Session/AddTrackersEnabled", "Preferences/Bittorrent/AddTrackers"},
             {"BitTorrent/Session/AdditionalTrackers", "Preferences/Bittorrent/TrackersList"},
             {"BitTorrent/Session/IPFilteringEnabled", "Preferences/IPFilter/Enabled"},

src/gui/advancedsettings.cpp

@@ -87,7 +87,6 @@ enum AdvSettingsRows
     // seeding
     SUPER_SEEDING,
     // tracker
-    TRACKER_EXCHANGE,
     ANNOUNCE_ALL_TRACKERS,
     ANNOUNCE_IP,
 
@@ -186,8 +185,6 @@ void AdvancedSettings::saveAdvancedSettings()
     pref->useSystemIconTheme(cb_use_icon_theme.isChecked());
 #endif
     pref->setConfirmTorrentRecheck(cb_confirm_torrent_recheck.isChecked());
-    // Tracker exchange
-    session->setTrackerExchangeEnabled(cb_enable_tracker_ext.isChecked());
     session->setAnnounceToAllTrackers(cb_announce_all_trackers.isChecked());
 }
 
@@ -380,9 +377,6 @@ void AdvancedSettings::loadAdvancedSettings()
     // Torrent recheck confirmation
     cb_confirm_torrent_recheck.setChecked(pref->confirmTorrentRecheck());
     addRow(CONFIRM_RECHECK_TORRENT, tr("Confirm torrent recheck"), &cb_confirm_torrent_recheck);
-    // Tracker exchange
-    cb_enable_tracker_ext.setChecked(session->isTrackerExchangeEnabled());
-    addRow(TRACKER_EXCHANGE, tr("Exchange trackers with other peers"), &cb_enable_tracker_ext);
     // Announce to all trackers
     cb_announce_all_trackers.setChecked(session->announceToAllTrackers());
     addRow(ANNOUNCE_ALL_TRACKERS, tr("Always announce to all trackers"), &cb_announce_all_trackers);

src/gui/advancedsettings.h

@@ -79,7 +79,7 @@ private:
     QSpinBox spin_cache, spin_save_resume_data_interval, outgoing_ports_min, outgoing_ports_max, spin_list_refresh, spin_maxhalfopen, spin_tracker_port, spin_cache_ttl;
     QCheckBox cb_os_cache, cb_recheck_completed, cb_resolve_countries, cb_resolve_hosts, cb_super_seeding,
               cb_program_notifications, cb_torrent_added_notifications, cb_tracker_favicon, cb_tracker_status,
-              cb_confirm_torrent_recheck, cb_enable_tracker_ext, cb_listen_ipv6, cb_announce_all_trackers;
+              cb_confirm_torrent_recheck, cb_listen_ipv6, cb_announce_all_trackers;
     QComboBox combo_iface, combo_iface_address;
     QLineEdit txtAnnounceIP;