From 1e374ab639af7afbdffd3be3be22be4ba21858e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Sun, 17 Sep 2023 19:27:34 +0200
Subject: Network: acknowledgment using packet counter

---
 src/network/protocol.cpp | 67 ++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 8 deletions(-)

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

diff --git a/src/network/protocol.cpp b/src/network/protocol.cpp
index 93d171a..8e0de61 100644
--- a/src/network/protocol.cpp
+++ b/src/network/protocol.cpp
@@ -36,6 +36,8 @@ struct NetworkProtocol::ConnectionPriv
 	bool confirmedCookie = false;
 	ChannelState channel = monostate();
 	vector<vector<uint8_t>> secureOutQueue {};
+
+	vector<uint64_t> toAcknowledge {};
 };
 
 
@@ -74,6 +76,23 @@ NetworkProtocol::~NetworkProtocol()
 
 NetworkProtocol::PollResult NetworkProtocol::poll()
 {
+	{
+		scoped_lock lock(protocolMutex);
+
+		for (const auto & c : connections) {
+			{
+				scoped_lock clock(c->cmutex);
+				if (c->toAcknowledge.empty())
+					continue;
+
+				if (not holds_alternative<unique_ptr<Channel>>(c->channel))
+					continue;
+			}
+			auto pst = self->ref()->storage().deriveEphemeralStorage();
+			c->send(pst, Header {{}}, {}, true);
+		}
+	}
+
 	sockaddr_in6 addr;
 	if (!recvfrom(buffer, addr))
 		return ProtocolClosed {};
@@ -90,7 +109,7 @@ NetworkProtocol::PollResult NetworkProtocol::poll()
 		}
 
 		auto pst = self->ref()->storage().deriveEphemeralStorage();
-		bool secure = false;
+		optional<uint64_t> secure = false;
 		if (auto header = Connection::parsePacket(buffer, nullptr, pst, secure)) {
 			if (auto conn = verifyNewConnection(*header, addr))
 				return NewConnection { move(*conn) };
@@ -315,12 +334,15 @@ optional<NetworkProtocol::Header> NetworkProtocol::Connection::receive(const Par
 		}
 	}
 
-	bool secure = false;
+	optional<uint64_t> secure = false;
 	if (auto header = parsePacket(buf, channel, partStorage, secure)) {
 		scoped_lock lock(p->cmutex);
 
-		if (secure)
+		if (secure) {
+			if (header->isAcknowledged())
+				p->toAcknowledge.push_back(*secure);
 			return header;
+		}
 
 		if (const auto * cookieEcho = header->lookupFirst<Header::CookieEcho>()) {
 			if (!p->protocol->verifyCookie(p->peerAddress, cookieEcho->value))
@@ -351,13 +373,13 @@ optional<NetworkProtocol::Header> NetworkProtocol::Connection::receive(const Par
 
 optional<NetworkProtocol::Header> NetworkProtocol::Connection::parsePacket(vector<uint8_t> & buf,
 		Channel * channel, const PartialStorage & partStorage,
-		bool & secure)
+		optional<uint64_t> & secure)
 {
 	vector<uint8_t> decrypted;
 	auto plainBegin = buf.cbegin();
 	auto plainEnd = buf.cbegin();
 
-	secure = false;
+	secure = nullopt;
 
 	if ((buf[0] & 0xE0) == 0x80) {
 		if (not channel) {
@@ -365,7 +387,7 @@ optional<NetworkProtocol::Header> NetworkProtocol::Connection::parsePacket(vecto
 			return nullopt;
 		}
 
-		if (auto dec = channel->decrypt(buf.begin() + 1, buf.end(), decrypted, 0)) {
+		if ((secure = channel->decrypt(buf.begin() + 1, buf.end(), decrypted, 0))) {
 			if (decrypted.empty()) {
 				std::cerr << "empty decrypted content\n";
 			}
@@ -378,8 +400,6 @@ optional<NetworkProtocol::Header> NetworkProtocol::Connection::parsePacket(vecto
 				return nullopt;
 			}
 		}
-
-		secure = true;
 	}
 	else if ((buf[0] & 0xE0) == 0x60) {
 		plainBegin = buf.begin();
@@ -431,6 +451,15 @@ bool NetworkProtocol::ConnectionPriv::send(const PartialStorage & partStorage,
 				header.items.push_back(Header::CookieSet { protocol->generateCookie(peerAddress) });
 		}
 
+		if (channel) {
+			for (auto num : toAcknowledge)
+				header.items.push_back(Header::AcknowledgedSingle { num });
+			toAcknowledge.clear();
+		}
+
+		if (header.items.empty())
+			return false;
+
 		part = header.toObject(partStorage).encode();
 		data.insert(data.end(), part.begin(), part.end());
 		for (const auto & obj : objs) {
@@ -533,6 +562,8 @@ optional<NetworkProtocol::Header> NetworkProtocol::Header::load(const PartialObj
 		if (item.name == "ACK") {
 			if (auto ref = item.asRef())
 				items.emplace_back(Acknowledged { ref->digest() });
+			else if (auto num = item.asInteger())
+				items.emplace_back(AcknowledgedSingle { static_cast<uint64_t>(*num) });
 		} else if (item.name == "VER") {
 			if (auto ver = item.asText())
 				items.emplace_back(Version { *ver });
@@ -583,6 +614,9 @@ PartialObject NetworkProtocol::Header::toObject(const PartialStorage & st) const
 		if (const auto * ptr = get_if<Acknowledged>(&item))
 			ritems.emplace_back("ACK", st.ref(ptr->value));
 
+		else if (const auto * ptr = get_if<AcknowledgedSingle>(&item))
+			ritems.emplace_back("ACK", Record::Item::Integer(ptr->value));
+
 		else if (const auto * ptr = get_if<Version>(&item))
 			ritems.emplace_back("VER", ptr->value);
 
@@ -623,4 +657,21 @@ PartialObject NetworkProtocol::Header::toObject(const PartialStorage & st) const
 	return PartialObject(PartialRecord(std::move(ritems)));
 }
 
+bool NetworkProtocol::Header::isAcknowledged() const
+{
+	for (const auto & item : items) {
+		if (holds_alternative<Acknowledged>(item)
+		 || holds_alternative<AcknowledgedSingle>(item)
+		 || holds_alternative<Version>(item)
+		 || holds_alternative<Initiation>(item)
+		 || holds_alternative<CookieSet>(item)
+		 || holds_alternative<CookieEcho>(item)
+		   )
+			continue;
+
+		return true;
+	}
+	return false;
+}
+
 }
-- 
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