From d0c48bf9b90dfbd55908a88a5aba411ca9b8e600 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Sun, 27 Aug 2023 21:52:29 +0200
Subject: Network: connection initiation with cookie

---
 src/network/protocol.h | 40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

(limited to 'src/network/protocol.h')

diff --git a/src/network/protocol.h b/src/network/protocol.h
index 545585e..dda2ffb 100644
--- a/src/network/protocol.h
+++ b/src/network/protocol.h
@@ -38,18 +38,23 @@ public:
 
 	struct Header;
 
+	struct ReceivedAnnounce;
 	struct NewConnection;
 	struct ConnectionReadReady;
 	struct ProtocolClosed {};
 
 	using PollResult = variant<
+		ReceivedAnnounce,
 		NewConnection,
 		ConnectionReadReady,
 		ProtocolClosed>;
 
 	PollResult poll();
 
+	struct Cookie { vector<uint8_t> value; };
+
 	using ChannelState = variant<monostate,
+		Cookie,
 		Stored<ChannelRequest>,
 		shared_ptr<struct WaitingRef>,
 		Stored<ChannelAccept>,
@@ -66,6 +71,12 @@ private:
 	bool recvfrom(vector<uint8_t> & buffer, sockaddr_in6 & addr);
 	void sendto(const vector<uint8_t> & buffer, variant<sockaddr_in, sockaddr_in6> addr);
 
+	void sendCookie(variant<sockaddr_in, sockaddr_in6> addr);
+	optional<Connection> verifyNewConnection(const Header & header, sockaddr_in6 addr);
+
+	Cookie generateCookie(variant<sockaddr_in, sockaddr_in6> addr) const;
+	bool verifyCookie(variant<sockaddr_in, sockaddr_in6> addr, const Cookie & cookie) const;
+
 	int sock;
 
 	mutex protocolMutex;
@@ -94,7 +105,7 @@ public:
 	const sockaddr_in6 & peerAddress() const;
 
 	optional<Header> receive(const PartialStorage &);
-	bool send(const PartialStorage &, const NetworkProtocol::Header &,
+	bool send(const PartialStorage &, NetworkProtocol::Header,
 			const vector<Object> &, bool secure);
 
 	void close();
@@ -104,9 +115,14 @@ public:
 	void trySendOutQueue();
 
 private:
+	static optional<Header> receive(vector<uint8_t> & buf,
+			Channel * channel,
+			const PartialStorage & st);
+
 	unique_ptr<ConnectionPriv> p;
 };
 
+struct NetworkProtocol::ReceivedAnnounce { sockaddr_in6 addr; Digest digest; };
 struct NetworkProtocol::NewConnection { Connection conn; };
 struct NetworkProtocol::ConnectionReadReady { Connection::Id id; };
 
@@ -114,6 +130,9 @@ struct NetworkProtocol::Header
 {
 	struct Acknowledged { Digest value; };
 	struct Version { string value; };
+	struct Initiation { Digest value; };
+	struct CookieSet { Cookie value; };
+	struct CookieEcho { Cookie value; };
 	struct DataRequest { Digest value; };
 	struct DataResponse { Digest value; };
 	struct AnnounceSelf { Digest value; };
@@ -126,6 +145,9 @@ struct NetworkProtocol::Header
 	using Item = variant<
 		Acknowledged,
 		Version,
+		Initiation,
+		CookieSet,
+		CookieEcho,
 		DataRequest,
 		DataResponse,
 		AnnounceSelf,
@@ -140,14 +162,28 @@ struct NetworkProtocol::Header
 	static optional<Header> load(const PartialObject &);
 	PartialObject toObject(const PartialStorage &) const;
 
-	const vector<Item> items;
+	template<class T> const T * lookupFirst() const;
+
+	vector<Item> items;
 };
 
+template<class T>
+const T * NetworkProtocol::Header::lookupFirst() const
+{
+	for (const auto & h : items)
+		if (auto ptr = std::get_if<T>(&h))
+			return ptr;
+	return nullptr;
+}
+
 bool operator==(const NetworkProtocol::Header::Item &, const NetworkProtocol::Header::Item &);
 inline bool operator!=(const NetworkProtocol::Header::Item & left,
 		const NetworkProtocol::Header::Item & right)
 { return not (left == right); }
 
+inline bool operator==(const NetworkProtocol::Cookie & left, const NetworkProtocol::Cookie & right)
+{ return left.value == right.value; }
+
 class ReplyBuilder
 {
 public:
-- 
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