Add feature to Socket so that it can send digests of data it has sent

and check those digests on receive.

6 files changed, 327 insertions, 1 deletions

diff --git a/src/lib/dcpomatic_socket.cc b/src/lib/dcpomatic_socket.cc
index ca910bb79..a0a7a1cf3 100644
--- a/src/lib/dcpomatic_socket.cc
+++ b/src/lib/dcpomatic_socket.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2015 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2020 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -21,12 +21,16 @@
 #include "dcpomatic_socket.h"
 #include "compose.hpp"
 #include "exceptions.h"
+#include "dcpomatic_assert.h"
 #include <boost/bind.hpp>
 #include <boost/lambda/lambda.hpp>
 #include <iostream>
 
 #include "i18n.h"
 
+using boost::shared_ptr;
+using boost::weak_ptr;
+
 /** @param timeout Timeout in seconds */
 Socket::Socket (int timeout)
 	: _deadline (_io_service)
@@ -89,6 +93,10 @@ Socket::write (uint8_t const * data, int size)
 	if (ec) {
 		throw NetworkError (String::compose (_("error during async_write (%1)"), ec.value ()));
 	}
+
+	if (_write_digester) {
+		_write_digester->add (data, static_cast<size_t>(size));
+	}
 }
 
 void
@@ -117,6 +125,10 @@ Socket::read (uint8_t* data, int size)
 	if (ec) {
 		throw NetworkError (String::compose (_("error during async_read (%1)"), ec.value ()));
 	}
+
+	if (_read_digester) {
+		_read_digester->add (data, static_cast<size_t>(size));
+	}
 }
 
 uint32_t
@@ -126,3 +138,98 @@ Socket::read_uint32 ()
 	read (reinterpret_cast<uint8_t *> (&v), 4);
 	return ntohl (v);
 }
+
+
+void
+Socket::start_read_digest ()
+{
+	DCPOMATIC_ASSERT (!_read_digester);
+	_read_digester.reset (new Digester());
+}
+
+void
+Socket::start_write_digest ()
+{
+	DCPOMATIC_ASSERT (!_write_digester);
+	_write_digester.reset (new Digester());
+}
+
+
+Socket::ReadDigestScope::ReadDigestScope (shared_ptr<Socket> socket)
+	: _socket (socket)
+{
+	socket->start_read_digest ();
+}
+
+
+bool
+Socket::ReadDigestScope::check ()
+{
+	shared_ptr<Socket> sp = _socket.lock ();
+	if (!sp) {
+		return false;
+	}
+
+	return sp->check_read_digest ();
+}
+
+
+Socket::WriteDigestScope::WriteDigestScope (shared_ptr<Socket> socket)
+	: _socket (socket)
+{
+	socket->start_write_digest ();
+}
+
+
+Socket::WriteDigestScope::~WriteDigestScope ()
+{
+	shared_ptr<Socket> sp = _socket.lock ();
+	if (sp) {
+		try {
+			sp->finish_write_digest ();
+		} catch (...) {
+			/* If we can't write our digest, something bad has happened
+			 * so let's just let it happen.
+			 */
+		}
+	}
+}
+
+
+bool
+Socket::check_read_digest ()
+{
+	DCPOMATIC_ASSERT (_read_digester);
+	int const size = _read_digester->size ();
+
+	uint8_t ref[size];
+	_read_digester->get (ref);
+
+	/* Make sure _read_digester is gone before we call read() so that the digest
+	 * isn't itself digested.
+	 */
+	_read_digester.reset ();
+
+	uint8_t actual[size];
+	read (actual, size);
+
+	return memcmp(ref, actual, size) == 0;
+}
+
+void
+Socket::finish_write_digest ()
+{
+	DCPOMATIC_ASSERT (_write_digester);
+	int const size = _write_digester->size();
+
+	uint8_t buffer[size];
+	_write_digester->get (buffer);
+
+	/* Make sure _write_digester is gone before we call write() so that the digest
+	 * isn't itself digested.
+	 */
+	_write_digester.reset ();
+
+	write (buffer, size);
+}
+
diff --git a/src/lib/dcpomatic_socket.h b/src/lib/dcpomatic_socket.h
index 870e7315c..1fa0b046f 100644
--- a/src/lib/dcpomatic_socket.h
+++ b/src/lib/dcpomatic_socket.h
@@ -18,8 +18,11 @@
 
 */
 
+#include "digester.h"
 #include <boost/asio.hpp>
 #include <boost/noncopyable.hpp>
+#include <boost/scoped_ptr.hpp>
+#include <boost/weak_ptr.hpp>
 
 /** @class Socket
  *  @brief A class to wrap a boost::asio::ip::tcp::socket with some things
@@ -46,8 +49,36 @@ public:
 	void read (uint8_t* data, int size);
 	uint32_t read_uint32 ();
 
+	class ReadDigestScope
+	{
+	public:
+		ReadDigestScope (boost::shared_ptr<Socket> socket);
+		bool check ();
+	private:
+		boost::weak_ptr<Socket> _socket;
+	};
+
+	/** After one of these is created everything that is sent from the socket will be
+	 *  added to a digest.  When the DigestScope is destroyed the digest will be sent
+	 *  from the socket.
+	 */
+	class WriteDigestScope
+	{
+	public:
+		WriteDigestScope (boost::shared_ptr<Socket> socket);
+		~WriteDigestScope ();
+	private:
+		boost::weak_ptr<Socket> _socket;
+	};
+
 private:
+	friend class DigestScope;
+
 	void check ();
+	void start_read_digest ();
+	bool check_read_digest ();
+	void start_write_digest ();
+	void finish_write_digest ();
 
 	Socket (Socket const &);
 
@@ -55,4 +86,6 @@ private:
 	boost::asio::deadline_timer _deadline;
 	boost::asio::ip::tcp::socket _socket;
 	int _timeout;
+	boost::scoped_ptr<Digester> _read_digester;
+	boost::scoped_ptr<Digester> _write_digester;
 };
diff --git a/src/lib/digester.cc b/src/lib/digester.cc
index 7bcc77646..452452ba4 100644
--- a/src/lib/digester.cc
+++ b/src/lib/digester.cc
@@ -19,6 +19,7 @@
 */
 
 #include "digester.h"
+#include "dcpomatic_assert.h"
 #include <nettle/md5.h>
 #include <iomanip>
 #include <cstdio>
@@ -67,3 +68,16 @@ Digester::get () const
 
 	return _digest.get ();
 }
+
+void
+Digester::get (uint8_t* buffer) const
+{
+	md5_digest (&_context, MD5_DIGEST_SIZE, buffer);
+}
+
+
+int
+Digester::size () const
+{
+	return MD5_DIGEST_SIZE;
+}
diff --git a/src/lib/digester.h b/src/lib/digester.h
index bec1f6416..6cdaf2331 100644
--- a/src/lib/digester.h
+++ b/src/lib/digester.h
@@ -40,6 +40,10 @@ public:
 
 	std::string get () const;
 
+	void get (uint8_t* buffer) const;
+
+	int size () const;
+
 private:
 	mutable md5_ctx _context;
 	mutable boost::optional<std::string> _digest;
diff --git a/test/socket_test.cc b/test/socket_test.cc
new file mode 100644
index 000000000..562d10639
--- /dev/null
+++ b/test/socket_test.cc
@@ -0,0 +1,167 @@
+/*
+    Copyright (C) 2020 Carl Hetherington <cth@carlh.net>
+
+    This file is part of DCP-o-matic.
+
+    DCP-o-matic is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    DCP-o-matic is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include "lib/server.h"
+#include "lib/dcpomatic_socket.h"
+#include <boost/thread.hpp>
+#include <boost/test/unit_test.hpp>
+#include <boost/shared_ptr.hpp>
+#include <cstring>
+#include <iostream>
+
+using boost::shared_ptr;
+using boost::bind;
+
+#define TEST_SERVER_PORT 9142
+#define TEST_SERVER_BUFFER_LENGTH 1024
+
+
+class TestServer : public Server
+{
+public:
+	TestServer (bool digest)
+		: Server (TEST_SERVER_PORT, 30)
+		, _buffer (new uint8_t[TEST_SERVER_BUFFER_LENGTH])
+		, _size (0)
+		, _result (false)
+		, _digest (digest)
+	{
+		_thread = boost::thread(bind(&TestServer::run, this));
+	}
+
+	~TestServer ()
+	{
+		stop ();
+		_thread.join ();
+		delete[] _buffer;
+	}
+
+	void expect (int size)
+	{
+		boost::mutex::scoped_lock lm (_mutex);
+		_size = size;
+	}
+
+	uint8_t const * buffer() const {
+		return _buffer;
+	}
+
+	void await ()
+	{
+		boost::mutex::scoped_lock lm (_mutex);
+		if (_size) {
+			_condition.wait (lm);
+		}
+	}
+
+	bool result () const {
+		return _result;
+	}
+
+private:
+	void handle (boost::shared_ptr<Socket> socket)
+	{
+		boost::mutex::scoped_lock lm (_mutex);
+		BOOST_REQUIRE (_size);
+		if (_digest) {
+			Socket::ReadDigestScope ds (socket);
+			socket->read (_buffer, _size);
+			_size = 0;
+			_condition.notify_one ();
+			_result = ds.check();
+		} else {
+			socket->read (_buffer, _size);
+			_size = 0;
+			_condition.notify_one ();
+		}
+	}
+
+	boost::thread _thread;
+	boost::mutex _mutex;
+	boost::condition _condition;
+	uint8_t* _buffer;
+	int _size;
+	bool _result;
+	bool _digest;
+};
+
+
+void
+send (shared_ptr<Socket> socket, char const* message)
+{
+	socket->write (reinterpret_cast<uint8_t const *>(message), strlen(message) + 1);
+}
+
+/** Basic test to see if Socket can send and receive data */
+BOOST_AUTO_TEST_CASE (socket_basic_test)
+{
+	TestServer server(false);
+	server.expect (13);
+
+	shared_ptr<Socket> socket (new Socket);
+	socket->connect (boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), TEST_SERVER_PORT));
+	send (socket, "Hello world!");
+
+	server.await ();
+	BOOST_CHECK_EQUAL(strcmp(reinterpret_cast<char const *>(server.buffer()), "Hello world!"), 0);
+}
+
+
+/** Check that the socket "auto-digest" creation works */
+BOOST_AUTO_TEST_CASE (socket_digest_test1)
+{
+	TestServer server(false);
+	server.expect (13 + 16);
+
+	shared_ptr<Socket> socket(new Socket);
+	socket->connect (boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), TEST_SERVER_PORT));
+	{
+		Socket::WriteDigestScope ds(socket);
+		send (socket, "Hello world!");
+	}
+
+	server.await ();
+	BOOST_CHECK_EQUAL(strcmp(reinterpret_cast<char const *>(server.buffer()), "Hello world!"), 0);
+
+	/* printf "%s\0" "Hello world!" | md5sum" in bash */
+	char ref[] = "\x59\x86\x88\xed\x18\xc8\x71\xdd\x57\xb9\xb7\x9f\x4b\x03\x14\xcf";
+	BOOST_CHECK_EQUAL (memcmp(server.buffer() + 13, ref, 16), 0);
+}
+
+
+/** Check that the socket "auto-digest" round-trip works */
+BOOST_AUTO_TEST_CASE (socket_digest_test2)
+{
+	TestServer server(true);
+	server.expect (13);
+
+	shared_ptr<Socket> socket(new Socket);
+	socket->connect (boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), TEST_SERVER_PORT));
+	{
+		Socket::WriteDigestScope ds(socket);
+		send (socket, "Hello world!");
+	}
+
+	server.await ();
+	BOOST_CHECK_EQUAL(strcmp(reinterpret_cast<char const *>(server.buffer()), "Hello world!"), 0);
+
+	BOOST_CHECK (server.result());
+}
+
diff --git a/test/wscript b/test/wscript
index a1a78eaea..4e5c57e0d 100644
--- a/test/wscript
+++ b/test/wscript
@@ -109,6 +109,7 @@ def build(bld):
                  silence_padding_test.cc
                  shuffler_test.cc
                  skip_frame_test.cc
+                 socket_test.cc
                  srt_subtitle_test.cc
                  ssa_subtitle_test.cc
                  stream_test.cc