Refactor blacklist/whitelist filter implementation (#253)

* refactored peer black/whitelist implementation

* improved filter loggins

- report line number containing invalid expression
- print warning and do not enable filter when no rules loaded
- report loaded rules count

src/base/CMakeLists.txt

@@ -106,8 +106,8 @@ add_library(qbt_base STATIC
     bittorrent/peer_blacklist.hpp
     bittorrent/peer_filter.hpp
     bittorrent/peer_filter_plugin.hpp
+    bittorrent/peer_filter_session_plugin.hpp
     bittorrent/peer_logger.hpp
-    bittorrent/peer_whitelist.hpp
     bittorrent/portforwarderimpl.cpp
     bittorrent/resumedatasavingmanager.cpp
     bittorrent/session.cpp

src/base/bittorrent/peer_blacklist.hpp

@@ -4,15 +4,11 @@
 
 #include <libtorrent/torrent_info.hpp>
 
-#include <QDir>
 #include <QHostAddress>
 
-#include "base/logger.h"
 #include "base/net/geoipmanager.h"
-#include "base/profile.h"
 
 #include "peer_filter_plugin.hpp"
-#include "peer_filter.hpp"
 #include "peer_logger.hpp"
 
 // bad peer filter
@@ -100,33 +96,3 @@ std::shared_ptr<lt::torrent_plugin> create_drop_bittorrent_media_player_plugin(l
 {
   return create_peer_action_plugin(th, wrap_filter(is_bittorrent_media_player, "bittorrent media player"), drop_connection);
 }
-
-std::shared_ptr<lt::torrent_plugin> create_peer_blacklist_plugin(lt::torrent_handle const&, client_data)
-{
-  QDir qbt_data_dir(specialFolderLocation(SpecialFolder::Data));
-
-  QString filter_file = qbt_data_dir.absoluteFilePath(QStringLiteral("peer_blacklist.txt"));
-  // do not create plugin if filter file doesn't exists
-  if (!QFile::exists(filter_file)) {
-    LogMsg("'peer_blacklist.txt' doesn't exist, do not enabling blacklist plugin", Log::INFO);
-    return nullptr;
-  }
-
-  // create filter object only once
-  static peer_filter filter(filter_file);
-  // do not create plugin if no rules were loaded
-  if (filter.is_empty()) {
-    LogMsg("'peer_blacklist.txt' has no valid rules, do not enabling blacklist plugin", Log::WARNING);
-    return nullptr;
-  }
-
-  auto peer_in_list = [&](const lt::peer_info& info, bool handshake, bool* stop_filtering) {
-    bool matched = filter.match_peer(info, false);
-    *stop_filtering = !handshake && !matched;
-    if (matched)
-      peer_logger_singleton::instance().log_peer(info, "blacklist");
-    return matched;
-  };
-
-  return std::make_shared<peer_action_plugin>(std::move(peer_in_list), drop_connection);
-}

src/base/bittorrent/peer_filter.hpp

@@ -36,13 +36,14 @@ class peer_filter
       QRegularExpression peer_id_re(QString::fromStdString(peer_id));
       QRegularExpression client_re(QString::fromStdString(client));
 
-      QString msg_tmpl("'%1': invalid %2 matching expression '%3' detected, ignoring rule");
+      QString msg_tmpl("'%1': invalid %2 matching expression '%3' detected at line %4, ignoring rule");
+      int line = m_filters.size() + 1;
 
       if (!peer_id_re.isValid())
-        LogMsg(msg_tmpl.arg(log_tag).arg("peer id").arg(peer_id_re.pattern()), Log::WARNING);
+        LogMsg(msg_tmpl.arg(log_tag).arg("peer id").arg(peer_id_re.pattern()).arg(line), Log::WARNING);
 
       if (!client_re.isValid())
-        LogMsg(msg_tmpl.arg(log_tag).arg("client name").arg(client_re.pattern()), Log::WARNING);
+        LogMsg(msg_tmpl.arg(log_tag).arg("client name").arg(client_re.pattern()).arg(line), Log::WARNING);
 
       if (peer_id_re.isValid() && client_re.isValid())
         m_filters.append({peer_id_re, client_re});
@@ -61,6 +62,7 @@ class peer_filter
   }
 
   bool is_empty() const { return m_filters.isEmpty(); }
+  int rules_count() const { return m_filters.size(); }
 
 private:
   QVector<QVector<QRegularExpression>> m_filters;

src/base/bittorrent/peer_filter_session_plugin.hpp

@@ -0,0 +1,85 @@
+#pragma once
+
+#include <QDir>
+
+#include "base/logger.h"
+#include "base/profile.h"
+
+#include "peer_filter_plugin.hpp"
+#include "peer_filter.hpp"
+#include "peer_logger.hpp"
+
+// filter factory function
+std::unique_ptr<peer_filter> create_peer_filter(const QString& filename)
+{
+  QDir qbt_data_dir(specialFolderLocation(SpecialFolder::Data));
+
+  QString filter_file = qbt_data_dir.absoluteFilePath(filename);
+  // do not create plugin if filter file doesn't exists
+  if (!QFile::exists(filter_file)) {
+    LogMsg(QString("'%1' doesn't exist, do not enabling filter").arg(filename), Log::NORMAL);
+    return nullptr;
+  }
+
+  auto filter = std::make_unique<peer_filter>(filter_file);
+  if (filter->is_empty()) {
+    LogMsg(QString("'%1' has no valid rules, do not enabling filter").arg(filename), Log::WARNING);
+    filter.reset();
+  } else {
+    LogMsg(QString("'%1' contains %2 valid rules").arg(filename).arg(filter->rules_count()), Log::INFO);
+  }
+
+  return filter;
+}
+
+
+// drop connection action
+void drop_peer_connection(lt::peer_connection_handle ph)
+{
+  ph.disconnect(boost::asio::error::connection_refused, lt::operation_t::bittorrent, lt::disconnect_severity_t{0});
+}
+
+
+class peer_filter_session_plugin final : public lt::plugin
+{
+public:
+  peer_filter_session_plugin()
+    : m_blacklist(create_peer_filter(QStringLiteral("peer_blacklist.txt")))
+    , m_whitelist(create_peer_filter(QStringLiteral("peer_whitelist.txt")))
+  {
+  }
+
+  std::shared_ptr<lt::torrent_plugin> new_torrent(const lt::torrent_handle&, client_data) override
+  {
+    // do not waste CPU and memory for useless objects when no filters are enabled
+    if (!m_blacklist && !m_whitelist)
+      return nullptr;
+    return std::make_shared<peer_action_plugin>([this](auto&&... args) { return filter(args...); }, drop_peer_connection);
+  }
+
+protected:
+  bool filter(const lt::peer_info& info, bool handshake, bool* stop_filtering) const
+  {
+    if (m_blacklist) {
+      bool matched = m_blacklist->match_peer(info, false);
+      *stop_filtering = !handshake && !matched;
+      if (matched)
+        peer_logger_singleton::instance().log_peer(info, "blacklist");
+      return matched;
+    }
+
+    if (m_whitelist) {
+      bool matched = m_whitelist->match_peer(info, handshake);
+      *stop_filtering = !handshake && matched;
+      if (!matched)
+        peer_logger_singleton::instance().log_peer(info, "whitelist");
+      return !matched;
+    }
+
+    return false;
+  }
+
+private:
+  std::unique_ptr<peer_filter> m_blacklist;
+  std::unique_ptr<peer_filter> m_whitelist;
+};

src/base/bittorrent/session.cpp

@@ -97,7 +97,7 @@
 #include "magneturi.h"
 #include "nativesessionextension.h"
 #include "peer_blacklist.hpp"
-#include "peer_whitelist.hpp"
+#include "peer_filter_session_plugin.hpp"
 #include "portforwarderimpl.h"
 #include "resumedatasavingmanager.h"
 #include "statistics.h"
@@ -1207,8 +1207,7 @@ void Session::initializeNativeSession()
     }
     if (isAutoBanBTPlayerPeerEnabled())
         m_nativeSession->add_extension(&create_drop_bittorrent_media_player_plugin);
-    m_nativeSession->add_extension(&create_peer_blacklist_plugin);
-    m_nativeSession->add_extension(&create_peer_whitelist_plugin);
+    m_nativeSession->add_extension(std::make_shared<peer_filter_session_plugin>());
 
     m_nativeSession->add_extension(std::make_shared<NativeSessionExtension>());
 }