Add a basic XMPP component implementation, doing the authentication

CMakeLists.txt

@@ -8,7 +8,16 @@ set(${PROJECT_NAME}_VERSION_MINOR 1)
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -pedantic -Wall -Wextra")
 set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -Og -fsanitize=address")
 
+#
+## Look for external libraries
+#
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/Modules/")
+find_package(Cryptopp REQUIRED)
+
 include_directories("src/")
+# the SYSTEM flag tells the compiler that we don't care about warnings
+# coming from these headers.
+include_directories(SYSTEM ${CRYPTO++_INCLUDE_DIR})
 
 #
 ## network

src/xmpp/xmpp_component.cpp

@@ -0,0 +1,137 @@
+#include <xmpp/xmpp_component.hpp>
+
+#include <iostream>
+
+// CryptoPP
+#include <filters.h>
+#include <hex.h>
+#include <sha.h>
+
+XmppComponent::XmppComponent(const std::string& hostname, const std::string& secret):
+  served_hostname(hostname),
+  secret(secret),
+  authenticated(false)
+{
+  this->parser.add_stream_open_callback(std::bind(&XmppComponent::on_remote_stream_open, this,
+                                                  std::placeholders::_1));
+  this->parser.add_stanza_callback(std::bind(&XmppComponent::on_stanza, this,
+                                                  std::placeholders::_1));
+  this->parser.add_stream_close_callback(std::bind(&XmppComponent::on_remote_stream_close, this,
+                                                  std::placeholders::_1));
+  this->stanza_handlers.emplace("handshake",
+                                std::bind(&XmppComponent::handle_handshake, this,std::placeholders::_1));
+}
+
+XmppComponent::~XmppComponent()
+{
+}
+
+void XmppComponent::start()
+{
+  this->connect(this->served_hostname, "5347");
+}
+
+void XmppComponent::send_stanza(const Stanza& stanza)
+{
+  std::cout << "====== Sending ========" << std::endl;
+  std::cout << stanza.to_string() << std::endl;
+  this->send_data(stanza.to_string());
+}
+
+void XmppComponent::on_connected()
+{
+  std::cout << "connected to XMPP server" << std::endl;
+  XmlNode node("stream:stream", nullptr);
+  node["xmlns"] = "jabber:component:accept";
+  node["xmlns:stream"] = "http://etherx.jabber.org/streams";
+  node["to"] = "irc.abricot";
+  this->send_stanza(node);
+
+}
+
+void XmppComponent::on_connection_close()
+{
+  std::cout << "XMPP server closed connection" << std::endl;
+}
+
+void XmppComponent::parse_in_buffer()
+{
+  this->parser.XML_Parse(this->in_buf.data(), this->in_buf.size(), false);
+  this->in_buf.clear();
+}
+
+void XmppComponent::on_remote_stream_open(const XmlNode& node)
+{
+  std::cout << "====== DOCUMENT_OPEN =======" << std::endl;
+  std::cout << node.to_string() << std::endl;
+  try
+    {
+      this->stream_id = node["id"];
+    }
+  catch (const AttributeNotFound& e)
+    {
+      std::cout << "Error: no attribute 'id' found" << std::endl;
+      this->send_stream_error("bad-format", "missing 'id' attribute");
+      this->close_document();
+      return ;
+    }
+
+  // Try to authenticate
+  CryptoPP::SHA1 sha1;
+  std::string digest;
+  CryptoPP::StringSource foo(this->stream_id + this->secret, true,
+                      new CryptoPP::HashFilter(sha1,
+                          new CryptoPP::HexEncoder(
+                              new CryptoPP::StringSink(digest), false)));
+  Stanza handshake("handshake", nullptr);
+  handshake.set_inner(digest);
+  handshake.close();
+  this->send_stanza(handshake);
+}
+
+void XmppComponent::on_remote_stream_close(const XmlNode& node)
+{
+  std::cout << "====== DOCUMENT_CLOSE =======" << std::endl;
+  std::cout << node.to_string() << std::endl;
+}
+
+void XmppComponent::on_stanza(const Stanza& stanza)
+{
+  std::cout << "=========== STANZA ============" << std::endl;
+  std::cout << stanza.to_string() << std::endl;
+  try
+    {
+      const auto& handler = this->stanza_handlers.at(stanza.get_name());
+      handler(stanza);
+    }
+  catch (const std::out_of_range& exception)
+    {
+      std::cout << "No handler for stanza of type " << stanza.get_name() << std::endl;
+      return;
+    }
+}
+
+void XmppComponent::send_stream_error(const std::string& name, const std::string& explanation)
+{
+  XmlNode node("stream:error", nullptr);
+  XmlNode error(name, nullptr);
+  error["xmlns"] = "urn:ietf:params:xml:ns:xmpp-streams";
+  if (!explanation.empty())
+    error.set_inner(explanation);
+  error.close();
+  node.add_child(std::move(error));
+  node.close();
+  this->send_stanza(node);
+}
+
+void XmppComponent::close_document()
+{
+  std::cout << "====== Sending ========" << std::endl;
+  std::cout << "</stream:stream>" << std::endl;
+  this->send_data("</stream:stream>");
+}
+
+void XmppComponent::handle_handshake(const Stanza& stanza)
+{
+  this->authenticated = true;
+}

src/xmpp/xmpp_component.hpp

@@ -0,0 +1,80 @@
+#ifndef XMPP_COMPONENT_INCLUDED
+# define XMPP_COMPONENT_INCLUDED
+
+#include <string>
+
+#include <network/socket_handler.hpp>
+
+#include <xmpp/xmpp_parser.hpp>
+
+#include <unordered_map>
+
+/**
+ * An XMPP component, communicating with an XMPP server using the protocole
+ * described in XEP-0114: Jabber Component Protocol
+ *
+ * TODO: implement XEP-0225: Component Connections
+ */
+class XmppComponent: public SocketHandler
+{
+public:
+  explicit XmppComponent(const std::string& hostname, const std::string& secret);
+  ~XmppComponent();
+  void on_connected();
+  void on_connection_close();
+  void parse_in_buffer();
+
+  /**
+   * Connect to the XMPP server
+   */
+  void start();
+  /**
+   * Serialize the stanza and add it to the out_buf to be sent to the
+   * server.
+   */
+  void send_stanza(const Stanza& stanza);
+  /**
+   * Handle the opening of the remote stream
+   */
+  void on_remote_stream_open(const XmlNode& node);
+  /**
+   * Handle the closing of the remote stream
+   */
+  void on_remote_stream_close(const XmlNode& node);
+  /**
+   * Handle received stanzas
+   */
+  void on_stanza(const Stanza& stanza);
+  /**
+   * Send an error stanza. Message being the name of the element inside the
+   * stanza, and explanation being a short human-readable sentence
+   * describing the error.
+   */
+  void send_stream_error(const std::string& message, const std::string& explanation);
+  /**
+   * Send the closing signal for our document (not closing the connection though).
+   */
+  void close_document();
+
+  /**
+   * Handle the various stanza types
+   */
+  void handle_handshake(const Stanza& stanza);
+
+private:
+  XmppParser parser;
+  std::string stream_id;
+  std::string served_hostname;
+  std::string secret;
+  bool authenticated;
+
+  std::unordered_map<std::string, std::function<void(const Stanza&)>> stanza_handlers;
+
+  XmppComponent(const XmppComponent&) = delete;
+  XmppComponent(XmppComponent&&) = delete;
+  XmppComponent& operator=(const XmppComponent&) = delete;
+  XmppComponent& operator=(XmppComponent&&) = delete;
+};
+
+#endif // XMPP_COMPONENT_INCLUDED
+