Add --peer-agent option

Add --peer-agent for setting the version/user agent used in the extended
handshake protocol for bittorrent.

src/Context.cc

@@ -166,6 +166,7 @@ Context::Context(bool standalone, int argc, char** argv, const KeyVals& options)
   }
 #ifdef ENABLE_BITTORRENT
   bittorrent::generateStaticPeerId(op->get(PREF_PEER_ID_PREFIX));
+  bittorrent::generateStaticPeerAgent(op->get(PREF_PEER_AGENT));
 #endif // ENABLE_BITTORRENT
   LogFactory::setLogFile(op->get(PREF_LOG));
   LogFactory::setLogLevel(op->get(PREF_LOG_LEVEL));

src/DefaultBtInteractive.cc

@@ -199,7 +199,7 @@ void DefaultBtInteractive::addPortMessageToQueue()
 void DefaultBtInteractive::addHandshakeExtendedMessageToQueue()
 {
   auto m = make_unique<HandshakeExtensionMessage>();
-  m->setClientVersion("aria2/" PACKAGE_VERSION);
+  m->setClientVersion(bittorrent::getStaticPeerAgent());
   m->setTCPPort(tcpPort_);
   m->setExtensions(extensionMessageRegistry_->getExtensions());
   auto attrs = bittorrent::getTorrentAttrs(downloadContext_);

src/OptionHandlerFactory.cc

@@ -1853,6 +1853,12 @@ std::vector<OptionHandler*> OptionHandlerFactory::createOptionHandlers()
     op->addTag(TAG_BITTORRENT);
     handlers.push_back(op);
   }
+  {
+    OptionHandler* op(new DefaultOptionHandler(
+        PREF_PEER_AGENT, TEXT_PEER_AGENT, "aria2/" PACKAGE_VERSION));
+    op->addTag(TAG_BITTORRENT);
+    handlers.push_back(op);
+  }
   {
     OptionHandler* op(new FloatNumberOptionHandler(
         PREF_SEED_TIME, TEXT_SEED_TIME, NO_DEFAULT_VALUE, 0));

src/bittorrent_helper.cc

@@ -88,6 +88,7 @@ const char C_COMMENT_UTF8[] = "comment.utf-8";
 const char C_CREATED_BY[] = "created by";
 
 const char DEFAULT_PEER_ID_PREFIX[] = "aria2-";
+const char DEFAULT_PEER_AGENT[] = "aria2/" PACKAGE_VERSION;
 } // namespace
 
 const std::string MULTI("multi");
@@ -693,6 +694,7 @@ std::string generatePeerId(const std::string& peerIdPrefix)
 
 namespace {
 std::string peerId;
+std::string peerAgent;
 } // namespace
 
 const std::string& generateStaticPeerId(const std::string& peerIdPrefix)
@@ -703,7 +705,16 @@ const std::string& generateStaticPeerId(const std::string& peerIdPrefix)
   return peerId;
 }
 
+const std::string& generateStaticPeerAgent(const std::string& peerAgentNew)
+{
+  if (peerAgent.empty()) {
+    peerAgent = peerAgentNew;
+  }
+  return peerAgent;
+}
+
 void setStaticPeerId(const std::string& newPeerId) { peerId = newPeerId; }
+void setStaticPeerAgent(const std::string& newPeerAgent) { peerAgent = newPeerAgent; }
 
 // If PeerID is not generated, it is created with default peerIdPrefix
 // (aria2-).
@@ -718,6 +729,16 @@ const unsigned char* getStaticPeerId()
   }
 }
 
+// If PeerAgent is not generated, it is created with default agent
+// aria2/PACKAGE_VERSION
+const std::string& getStaticPeerAgent()
+{
+  if (peerAgent.empty()) {
+    generateStaticPeerAgent(DEFAULT_PEER_AGENT);
+  }
+  return peerAgent;
+}
+
 uint8_t getId(const unsigned char* msg) { return msg[0]; }
 
 uint64_t getLLIntParam(const unsigned char* msg, size_t pos)

src/bittorrent_helper.h

@@ -134,15 +134,21 @@ std::string generatePeerId(const std::string& peerIdPrefix);
 // uses generatePeerId(peerIdPrefix) to produce Peer ID.
 const std::string& generateStaticPeerId(const std::string& peerIdPrefix);
 
+const std::string& generateStaticPeerAgent(const std::string& peerAgent);
+
 // Returns Peer ID statically stored by generateStaticPeerId().  If
 // Peer ID is not stored yet, this function calls
 // generateStaticPeerId("aria2-")
 const unsigned char* getStaticPeerId();
 
+const std::string& getStaticPeerAgent();
+
 // Set newPeerId as a static Peer ID. newPeerId must be 20-byte
 // length.
 void setStaticPeerId(const std::string& newPeerId);
 
+void setStaticPeerAgent(const std::string& newPeerAgent);
+
 // Computes fast set index and returns them.
 std::vector<size_t> computeFastSet(const std::string& ipaddr, size_t numPieces,
                                    const unsigned char* infoHash,

src/prefs.cc

@@ -482,6 +482,8 @@ PrefPtr PREF_SEED_RATIO = makePref("seed-ratio");
 PrefPtr PREF_BT_KEEP_ALIVE_INTERVAL = makePref("bt-keep-alive-interval");
 // values: a string, less than or equals to 20 bytes length
 PrefPtr PREF_PEER_ID_PREFIX = makePref("peer-id-prefix");
+// values: a string representing the extended BT handshake peer user agent
+PrefPtr PREF_PEER_AGENT = makePref("peer-agent");
 // values: true | false
 PrefPtr PREF_ENABLE_PEER_EXCHANGE = makePref("enable-peer-exchange");
 // values: true | false

src/prefs.h

@@ -434,6 +434,8 @@ extern PrefPtr PREF_SEED_RATIO;
 extern PrefPtr PREF_BT_KEEP_ALIVE_INTERVAL;
 // values: a string, less than or equals to 20 bytes length
 extern PrefPtr PREF_PEER_ID_PREFIX;
+// values: a string representing the extended BT handshake peer user agent
+extern PrefPtr PREF_PEER_AGENT;
 // values: true | false
 extern PrefPtr PREF_ENABLE_PEER_EXCHANGE;
 // values: true | false

src/usage_text.h

@@ -331,6 +331,8 @@
     "                              bytes are specified, only first 20 bytes are\n" \
     "                              used. If less than 20 bytes are specified, random\n" \
     "                              byte data are added to make its length 20 bytes.")
+#define TEXT_PEER_AGENT                                                 \
+  _(" --peer-agent=PEER_AGENT  Set client reported during Extended torrent handshakes")
 #define TEXT_ENABLE_PEER_EXCHANGE                                       \
   _(" --enable-peer-exchange[=true|false] Enable Peer Exchange extension.")
 #define TEXT_ENABLE_DHT                                         \

test/BittorrentHelperTest.cc

@@ -42,6 +42,7 @@ class BittorrentHelperTest : public CppUnit::TestFixture {
   CPPUNIT_TEST(testGetPieceLength);
   CPPUNIT_TEST(testGetInfoHashAsString);
   CPPUNIT_TEST(testGetPeerId);
+  CPPUNIT_TEST(testGetPeerAgent);
   CPPUNIT_TEST(testComputeFastSet);
   CPPUNIT_TEST(testGetFileEntries_multiFileUrlList);
   CPPUNIT_TEST(testGetFileEntries_singleFileUrlList);
@@ -100,6 +101,7 @@ public:
   void testGetPieceLength();
   void testGetInfoHashAsString();
   void testGetPeerId();
+  void testGetPeerAgent();
   void testComputeFastSet();
   void testGetFileEntries_multiFileUrlList();
   void testGetFileEntries_singleFileUrlList();
@@ -325,6 +327,13 @@ void BittorrentHelperTest::testGetPeerId()
   CPPUNIT_ASSERT_EQUAL((size_t)20, peerId.size());
 }
 
+void BittorrentHelperTest::testGetPeerAgent()
+{
+  std::string peerAgent = generateStaticPeerAgent("aria2/-1.-1.-1");
+  CPPUNIT_ASSERT_EQUAL(std::string("aria2/-1.-1.-1"), peerAgent);
+  CPPUNIT_ASSERT_EQUAL(std::string("aria2/-1.-1.-1"), bittorrent::getStaticPeerAgent());
+}
+
 void BittorrentHelperTest::testComputeFastSet()
 {
   std::string ipaddr = "192.168.0.1";