Add allow_multiple_connections_per_ip knob. Closes #5884.

src/base/bittorrent/session.cpp

@@ -284,6 +284,7 @@ Session::Session(QObject *parent)
     , m_isUTPEnabled(BITTORRENT_SESSION_KEY("uTPEnabled"), true)
     , m_isUTPRateLimited(BITTORRENT_SESSION_KEY("uTPRateLimited"), true)
     , m_utpMixedMode(BITTORRENT_SESSION_KEY("uTPMixedMode"), m_isUTPEnabled)
+    , m_multiConnectionsPerIpEnabled(BITTORRENT_SESSION_KEY("MultiConnectionsPerIp"), false)
     , m_isAddTrackersEnabled(BITTORRENT_SESSION_KEY("AddTrackersEnabled"), false)
     , m_additionalTrackers(BITTORRENT_SESSION_KEY("AdditionalTrackers"))
     , m_globalMaxRatio(BITTORRENT_SESSION_KEY("GlobalMaxRatio"), -1, [](qreal r) { return r < 0 ? -1. : r;})
@@ -1310,6 +1311,8 @@ void Session::configure(libtorrent::settings_pack &settingsPack)
         break;
     }
 
+    settingsPack.set_bool(libt::settings_pack::allow_multiple_connections_per_ip, multiConnectionsPerIpEnabled());
+
     settingsPack.set_bool(libt::settings_pack::apply_ip_filter_to_trackers, isTrackerFilteringEnabled());
 
     settingsPack.set_bool(libt::settings_pack::enable_dht, isDHTEnabled());
@@ -1538,6 +1541,8 @@ void Session::configure(libtorrent::session_settings &sessionSettings)
         break;
     }
 
+    sessionSettings.allow_multiple_connections_per_ip = multiConnectionsPerIpEnabled();
+
     sessionSettings.apply_ip_filter_to_trackers = isTrackerFilteringEnabled();
 
     if (isDHTEnabled()) {
@@ -3116,6 +3121,19 @@ void Session::setUtpMixedMode(int mode)
     configureDeferred();
 }
 
+bool Session::multiConnectionsPerIpEnabled() const
+{
+    return m_multiConnectionsPerIpEnabled;
+}
+
+void Session::setMultiConnectionsPerIpEnabled(bool enabled)
+{
+    if (enabled == m_multiConnectionsPerIpEnabled) return;
+
+    m_multiConnectionsPerIpEnabled = enabled;
+    configureDeferred();
+}
+
 bool Session::isTrackerFilteringEnabled() const
 {
     return m_isTrackerFilteringEnabled;

src/base/bittorrent/session.h

@@ -375,6 +375,8 @@ namespace BitTorrent
         void setUTPRateLimited(bool limited);
         int utpMixedMode() const;
         void setUtpMixedMode(int mode);
+        bool multiConnectionsPerIpEnabled() const;
+        void setMultiConnectionsPerIpEnabled(bool enabled);
         bool isTrackerFilteringEnabled() const;
         void setTrackerFilteringEnabled(bool enabled);
         QStringList bannedIPs() const;
@@ -600,6 +602,7 @@ namespace BitTorrent
         CachedSettingValue<bool> m_isUTPEnabled;
         CachedSettingValue<bool> m_isUTPRateLimited;
         CachedSettingValue<int> m_utpMixedMode;
+        CachedSettingValue<bool> m_multiConnectionsPerIpEnabled;
         CachedSettingValue<bool> m_isAddTrackersEnabled;
         CachedSettingValue<QString> m_additionalTrackers;
         CachedSettingValue<qreal> m_globalMaxRatio;

src/gui/advancedsettings.cpp

@@ -84,6 +84,7 @@ enum AdvSettingsRows
     OUTGOING_PORT_MIN,
     OUTGOING_PORT_MAX,
     UTP_MIX_MODE,
+    MULTI_CONNECTIONS_PER_IP,
     // embedded tracker
     TRACKER_STATUS,
     TRACKER_PORT,
@@ -138,6 +139,8 @@ void AdvancedSettings::saveAdvancedSettings()
     session->setOutgoingPortsMax(outgoing_ports_max.value());
     // uTP-TCP mixed mode
     session->setUtpMixedMode(comboUtpMixedMode.currentIndex());
+    // multiple connections per IP
+    session->setMultiConnectionsPerIpEnabled(cbMultiConnectionsPerIp.isChecked());
     // Recheck torrents on completion
     pref->recheckTorrentsOnCompletion(cb_recheck_completed.isChecked());
     // Transfer list refresh interval
@@ -307,6 +310,9 @@ void AdvancedSettings::loadAdvancedSettings()
     comboUtpMixedMode.addItems({"Prefer TCP", "Peer proportional (throttles TCP)"});
     comboUtpMixedMode.setCurrentIndex(session->utpMixedMode());
     addRow(UTP_MIX_MODE, tr("uTP-TCP mixed mode algorithm"), &comboUtpMixedMode);
+    // multiple connections per IP
+    cbMultiConnectionsPerIp.setChecked(session->multiConnectionsPerIpEnabled());
+    addRow(MULTI_CONNECTIONS_PER_IP, tr("Allow multiple connections from the same IP address"), &cbMultiConnectionsPerIp);
     // Recheck completed torrents
     cb_recheck_completed.setChecked(pref->recheckTorrentsOnCompletion());
     addRow(RECHECK_COMPLETED, tr("Recheck torrents on completion"), &cb_recheck_completed);

src/gui/advancedsettings.h

@@ -78,7 +78,7 @@ 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_confirm_remove_all_tags, cb_listen_ipv6, cb_announce_all_trackers, cbGuidedReadCache;
+              cb_confirm_torrent_recheck, cb_confirm_remove_all_tags, cb_listen_ipv6, cb_announce_all_trackers, cbGuidedReadCache, cbMultiConnectionsPerIp;
     QComboBox combo_iface, combo_iface_address, comboUtpMixedMode;
     QLineEdit txtAnnounceIP;