From 2ed8103ff1c0fca7372b3c3888f590ba41c525e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Sun, 13 Aug 2023 19:01:48 +0200
Subject: Connection class for network protocol

---
 src/network/protocol.cpp | 129 +++++++++++++++++++++++++++++++++++++++++++++++
 src/network/protocol.h   |  55 ++++++++++++++++++++
 2 files changed, 184 insertions(+)

(limited to 'src/network')

diff --git a/src/network/protocol.cpp b/src/network/protocol.cpp
index 63cfde5..c247bf0 100644
--- a/src/network/protocol.cpp
+++ b/src/network/protocol.cpp
@@ -3,10 +3,27 @@
 #include <sys/socket.h>
 #include <unistd.h>
 
+#include <cstring>
+#include <mutex>
 #include <system_error>
 
+using std::move;
+using std::scoped_lock;
+
 namespace erebos {
 
+struct NetworkProtocol::ConnectionPriv
+{
+	Connection::Id id() const;
+
+	NetworkProtocol * protocol;
+	const sockaddr_in6 peerAddress;
+
+	mutex cmutex {};
+	vector<uint8_t> buffer {};
+};
+
+
 NetworkProtocol::NetworkProtocol():
 	sock(-1)
 {}
@@ -32,6 +49,44 @@ NetworkProtocol::~NetworkProtocol()
 {
 	if (sock >= 0)
 		close(sock);
+
+	for (auto & c : connections)
+		c->protocol = nullptr;
+}
+
+NetworkProtocol::PollResult NetworkProtocol::poll()
+{
+	sockaddr_in6 addr;
+	if (!recvfrom(buffer, addr))
+		return ProtocolClosed {};
+
+	scoped_lock lock(protocolMutex);
+	for (const auto & c : connections) {
+		if (memcmp(&c->peerAddress, &addr, sizeof addr) == 0) {
+			scoped_lock clock(c->cmutex);
+			buffer.swap(c->buffer);
+			return ConnectionReadReady { c->id() };
+		}
+	}
+
+	auto conn = unique_ptr<ConnectionPriv>(new ConnectionPriv {
+		.protocol = this,
+		.peerAddress = addr,
+	});
+
+	connections.push_back(conn.get());
+	buffer.swap(conn->buffer);
+	return NewConnection { Connection(move(conn)) };
+}
+
+NetworkProtocol::Connection NetworkProtocol::connect(sockaddr_in6 addr)
+{
+	auto conn = unique_ptr<ConnectionPriv>(new ConnectionPriv {
+		.protocol = this,
+		.peerAddress = addr,
+	});
+	connections.push_back(conn.get());
+	return Connection(move(conn));
 }
 
 bool NetworkProtocol::recvfrom(vector<uint8_t> & buffer, sockaddr_in6 & addr)
@@ -66,4 +121,78 @@ void NetworkProtocol::shutdown()
 	::shutdown(sock, SHUT_RDWR);
 }
 
+
+NetworkProtocol::Connection::Id NetworkProtocol::ConnectionPriv::id() const
+{
+	return reinterpret_cast<uintptr_t>(this);
+}
+
+NetworkProtocol::Connection::Connection(unique_ptr<ConnectionPriv> p_):
+	p(move(p_))
+{
+}
+
+NetworkProtocol::Connection::Connection(Connection && other):
+	p(move(other.p))
+{
+}
+
+NetworkProtocol::Connection & NetworkProtocol::Connection::operator=(Connection && other)
+{
+	close();
+	p = move(other.p);
+	return *this;
+}
+
+NetworkProtocol::Connection::~Connection()
+{
+	close();
+}
+
+NetworkProtocol::Connection::Id NetworkProtocol::Connection::id() const
+{
+	return p->id();
+}
+
+const sockaddr_in6 & NetworkProtocol::Connection::peerAddress() const
+{
+	return p->peerAddress;
+}
+
+bool NetworkProtocol::Connection::receive(vector<uint8_t> & buffer)
+{
+	scoped_lock lock(p->cmutex);
+	if (p->buffer.empty())
+		return false;
+
+	buffer.swap(p->buffer);
+	p->buffer.clear();
+	return true;
+}
+
+bool NetworkProtocol::Connection::send(const vector<uint8_t> & buffer)
+{
+	p->protocol->sendto(buffer, p->peerAddress);
+	return true;
+}
+
+void NetworkProtocol::Connection::close()
+{
+	if (not p)
+		return;
+
+	if (p->protocol) {
+		scoped_lock lock(p->protocol->protocolMutex);
+		for (auto it = p->protocol->connections.begin();
+				it != p->protocol->connections.end(); it++) {
+			if ((*it) == p.get()) {
+				p->protocol->connections.erase(it);
+				break;
+			}
+		}
+	}
+
+	p = nullptr;
+}
+
 }
diff --git a/src/network/protocol.h b/src/network/protocol.h
index 6a22f3b..a9bbaff 100644
--- a/src/network/protocol.h
+++ b/src/network/protocol.h
@@ -3,10 +3,16 @@
 #include <netinet/in.h>
 
 #include <cstdint>
+#include <memory>
+#include <mutex>
+#include <variant>
 #include <vector>
 
 namespace erebos {
 
+using std::mutex;
+using std::unique_ptr;
+using std::variant;
 using std::vector;
 
 class NetworkProtocol
@@ -20,6 +26,21 @@ public:
 	NetworkProtocol & operator=(NetworkProtocol &&);
 	~NetworkProtocol();
 
+	class Connection;
+
+	struct NewConnection;
+	struct ConnectionReadReady;
+	struct ProtocolClosed {};
+
+	using PollResult = variant<
+		NewConnection,
+		ConnectionReadReady,
+		ProtocolClosed>;
+
+	PollResult poll();
+
+	Connection connect(sockaddr_in6 addr);
+
 	bool recvfrom(vector<uint8_t> & buffer, sockaddr_in6 & addr);
 	void sendto(const vector<uint8_t> & buffer, sockaddr_in addr);
 	void sendto(const vector<uint8_t> & buffer, sockaddr_in6 addr);
@@ -28,6 +49,40 @@ public:
 
 private:
 	int sock;
+
+	mutex protocolMutex;
+	vector<uint8_t> buffer;
+
+	struct ConnectionPriv;
+	vector<ConnectionPriv *> connections;
+};
+
+class NetworkProtocol::Connection
+{
+	friend class NetworkProtocol;
+	Connection(unique_ptr<ConnectionPriv> p);
+public:
+	Connection(const Connection &) = delete;
+	Connection(Connection &&);
+	Connection & operator=(const Connection &) = delete;
+	Connection & operator=(Connection &&);
+	~Connection();
+
+	using Id = uintptr_t;
+	Id id() const;
+
+	const sockaddr_in6 & peerAddress() const;
+
+	bool receive(vector<uint8_t> & buffer);
+	bool send(const vector<uint8_t> & buffer);
+
+	void close();
+
+private:
+	unique_ptr<ConnectionPriv> p;
 };
 
+struct NetworkProtocol::NewConnection { Connection conn; };
+struct NetworkProtocol::ConnectionReadReady { Connection::Id id; };
+
 }
-- 
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