eclipse-paho#311 Added ALPN protocols to the SSL options

src/mqtt/exception.h

@@ -168,6 +168,9 @@ inline std::ostream& operator<<(std::ostream& os, const exception& exc) {
 
 /////////////////////////////////////////////////////////////////////////////
 
+/**
+ * Exception thrown when an expected server response is missing.
+ */
 class missing_response : public exception
 {
 public:
@@ -178,6 +181,9 @@ class missing_response : public exception
 
 /////////////////////////////////////////////////////////////////////////////
 
+/**
+ * A timeout exception, particularly from the synchronous client.
+ */
 class timeout_error : public exception
 {
 public:

src/mqtt/ssl_options.h

@@ -2,7 +2,7 @@
 /// @file ssl_options.h
 /// Declaration of MQTT ssl_options class
 /// @date Jul 7, 2016
-/// @author Guilherme Ferreira
+/// @author Frank Pagliughi, Guilherme Ferreira
 /////////////////////////////////////////////////////////////////////////////
 
 /*******************************************************************************
@@ -95,9 +95,13 @@ class ssl_options
 
 	/** Error message callback handler  */
 	error_handler errHandler_;
+
 	/** PSK callback handler */
 	psk_handler pskHandler_;
 
+	/** ALPN protocol list, in wire format */
+	std::basic_string<unsigned char> protos_;
+
 	/** Callbacks from the C library */
 	static int on_error(const char *str, size_t len, void *context);
 	static unsigned on_psk(const char *hint, char *identity, unsigned int max_identity_len,
@@ -145,7 +149,8 @@ class ssl_options
 	 */
 	ssl_options(const string& trustStore, const string& keyStore,
 				const string& privateKey, const string& privateKeyPassword,
-				const string& enabledCipherSuites, bool enableServerCertAuth);
+				const string& enabledCipherSuites, bool enableServerCertAuth,
+				const std::vector<string> alpnProtos=std::vector<string>());
 	/**
 	 * Copy constructor.
 	 * @param opt The other options to copy.
@@ -313,6 +318,18 @@ class ssl_options
 	 * @param cb The callback.
 	 */
 	void set_psk_handler(psk_handler cb);
+	/**
+	 * Gets the list of supported ALPN protocols.
+	 * @return A vector containing the supported ALPN protocols.
+	 */
+	std::vector<string> get_alpn_protos() const;
+	/**
+	 * Sets the list of supported ALPN protolols.
+	 * See:
+	 * https://www.openssl.org/docs/man1.1.0/man3/SSL_CTX_set_alpn_protos.html
+	 * @param protos The list of ALPN protocols to be negotiated.
+	 */
+	void set_alpn_protos(const std::vector<string>& protos);
 };
 
 /**
@@ -453,6 +470,14 @@ class ssl_options_builder
 		opts_.set_psk_handler(cb);
 		return *this;
 	}
+	/**
+	 * Sets the list of supported ALPN protocols.
+	 * @param protos The list of ALPN protocols to be negotiated.
+	 */
+	auto alpn_protos(const std::vector<string>& protos) -> self& {
+		opts_.set_alpn_protos(protos);
+		return *this;
+	}
 	/**
 	 * Finish building the options and return them.
 	 * @return The option struct as built.

src/ssl_options.cpp

@@ -31,28 +31,34 @@ ssl_options::ssl_options() : opts_(DFLT_C_STRUCT)
 
 ssl_options::ssl_options(const string& trustStore, const string& keyStore,
 						 const string& privateKey, const string& privateKeyPassword,
-						 const string& enabledCipherSuites, bool enableServerCertAuth)
+						 const string& enabledCipherSuites, bool enableServerCertAuth,
+						 const std::vector<string> alpnProtos /*=std::vector<string>()*/)
 			: opts_(DFLT_C_STRUCT), trustStore_(trustStore), keyStore_(keyStore),
 				privateKey_(privateKey), privateKeyPassword_(privateKeyPassword),
 				enabledCipherSuites_(enabledCipherSuites)
 {
+	set_alpn_protos(alpnProtos);
 	update_c_struct();
 	opts_.enableServerCertAuth = enableServerCertAuth;
 }
 
-ssl_options::ssl_options(const ssl_options& opt)
-		: opts_(opt.opts_), trustStore_(opt.trustStore_), keyStore_(opt.keyStore_),
-			privateKey_(opt.privateKey_), privateKeyPassword_(opt.privateKeyPassword_),
-			enabledCipherSuites_(opt.enabledCipherSuites_)
+ssl_options::ssl_options(const ssl_options& other)
+		: opts_(other.opts_), trustStore_(other.trustStore_), keyStore_(other.keyStore_),
+			privateKey_(other.privateKey_), privateKeyPassword_(other.privateKeyPassword_),
+			enabledCipherSuites_(other.enabledCipherSuites_),
+			errHandler_(other.errHandler_), pskHandler_(other.pskHandler_),
+			protos_(other.protos_)
 {
 	update_c_struct();
 }
 
-ssl_options::ssl_options(ssl_options&& opt)
-		: opts_(opt.opts_), trustStore_(std::move(opt.trustStore_)),
-			keyStore_(std::move(opt.keyStore_)), privateKey_(std::move(opt.privateKey_)),
-			privateKeyPassword_(std::move(opt.privateKeyPassword_)),
-			enabledCipherSuites_(std::move(opt.enabledCipherSuites_))
+ssl_options::ssl_options(ssl_options&& other)
+		: opts_(other.opts_), trustStore_(std::move(other.trustStore_)),
+			keyStore_(std::move(other.keyStore_)), privateKey_(std::move(other.privateKey_)),
+			privateKeyPassword_(std::move(other.privateKeyPassword_)),
+			enabledCipherSuites_(std::move(other.enabledCipherSuites_)),
+			errHandler_(std::move(other.errHandler_)), pskHandler_(std::move(other.pskHandler_)),
+			protos_(std::move(other.protos_))
 {
 	update_c_struct();
 }
@@ -82,6 +88,15 @@ void ssl_options::update_c_struct()
 		opts_.ssl_psk_cb = nullptr;
 		opts_.ssl_psk_context = nullptr;
 	}
+
+	if (!protos_.empty()) {
+		opts_.protos = protos_.data();
+		opts_.protos_len = unsigned(protos_.length());
+	}
+	else {
+		opts_.protos = nullptr;
+		opts_.protos_len = 0;
+	}
 }
 
 // --------------------------------------------------------------------------
@@ -144,6 +159,11 @@ ssl_options& ssl_options::operator=(const ssl_options& rhs)
 	privateKeyPassword_ = rhs.privateKeyPassword_;
 	enabledCipherSuites_ = rhs.enabledCipherSuites_;
 
+	errHandler_ = rhs.errHandler_;
+	pskHandler_ = rhs.pskHandler_;
+
+	protos_ = rhs.protos_;
+
 	update_c_struct();
 	return *this;
 }
@@ -161,6 +181,11 @@ ssl_options& ssl_options::operator=(ssl_options&& rhs)
 	privateKeyPassword_ = std::move(rhs.privateKeyPassword_);
 	enabledCipherSuites_ = std::move(rhs.enabledCipherSuites_);
 
+	errHandler_ = std::move(rhs.errHandler_);
+	pskHandler_ = std::move(rhs.pskHandler_);
+
+	protos_ = std::move(rhs.protos_);
+
 	update_c_struct();
 	return *this;
 }
@@ -236,6 +261,55 @@ void ssl_options::set_psk_handler(psk_handler cb)
 	}
 }
 
+// Gets the list of ALPN protocols.
+// To do so, it must recover the strings from the wire format.
+std::vector<string> ssl_options::get_alpn_protos() const
+{
+	std::vector<string> protos;
+	size_t i = 0, n = protos_.length();
+
+	while (i < n) {
+		size_t sn = protos_[i++];
+		if (i+sn > n) break;
+
+		string s;
+		s.reserve(sn);
+
+		sn += i;
+		while (i < sn)
+			s.push_back(char(protos_[i++]));
+		protos.push_back(std::move(s));
+	}
+	return protos;
+}
+
+// Converts the vector of names into the binary string in wire format.
+// This is a single string uf unsigned characters with each protocol
+// prepended by a byte of its length.
+void ssl_options::set_alpn_protos(const std::vector<string>& protos)
+{
+	using uchar = unsigned char;
+
+	if (!protos.empty()) {
+		std::basic_string<uchar> protoBin;
+		for (const auto& proto : protos) {
+			protoBin.push_back(uchar(proto.length()));
+			for (const char c : proto)
+				protoBin.push_back(uchar(c));
+		}
+		protos_ = std::move(protoBin);
+
+		opts_.protos = protos_.data();
+		opts_.protos_len = unsigned(protos_.length());
+	}
+	else {
+		protos_ = std::basic_string<uchar>();
+		opts_.protos = nullptr;
+		opts_.protos_len = 0;
+	}
+}
+
 /////////////////////////////////////////////////////////////////////////////
-} // end namespace mqtt
+// end namespace mqtt
+}