approval-voting improvement: include all tranche0 assignments in one certificate (#1178)

**_PR migrated from https://github.com/paritytech/polkadot/pull/6782_** 

This PR will upgrade the network protocol to version 3 -> VStaging which
will later be renamed to V3. This version introduces a new kind of
assignment certificate that will be used for tranche0 assignments.
Instead of issuing/importing one tranche0 assignment per candidate,
there will be just one certificate per relay chain block per validator.
However, we will not be sending out the new assignment certificates,
yet. So everything should work exactly as before. Once the majority of
the validators have been upgraded to the new protocol version we will
enable the new certificates (starting at a specific relay chain block)
with a new client update.

There are still a few things that need to be done:

- [x] Use bitfield instead of Vec<CandidateIndex>:
https://github.com/paritytech/polkadot/pull/6802
  - [x] Fix existing approval-distribution and approval-voting tests
  - [x] Fix bitfield-distribution and statement-distribution tests
  - [x] Fix network bridge tests
  - [x] Implement todos in the code
  - [x] Add tests to cover new code
  - [x] Update metrics
  - [x] Remove the approval distribution aggression levels: TBD PR
  - [x] Parachains DB migration 
  - [x] Test network protocol upgrade on Versi
  - [x] Versi Load test
  - [x] Add Zombienet test
  - [x] Documentation updates
- [x] Fix for sending DistributeAssignment for each candidate claimed by
a v2 assignment (warning: Importing locally an already known assignment)
 - [x]  Fix AcceptedDuplicate
 - [x] Fix DB migration so that we can still keep old data.
 - [x] Final Versi burn in

---------

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>
Signed-off-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io>
Co-authored-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io>

polkadot/node/network/bridge/src/network.rs

@@ -28,23 +28,129 @@ use sc_network::{
 };
 
 use polkadot_node_network_protocol::{
-	peer_set::{PeerSet, PeerSetProtocolNames, ProtocolVersion},
+	peer_set::{
+		CollationVersion, PeerSet, PeerSetProtocolNames, ProtocolVersion, ValidationVersion,
+	},
 	request_response::{OutgoingRequest, Recipient, ReqProtocolNames, Requests},
-	PeerId,
+	v1 as protocol_v1, v2 as protocol_v2, vstaging as protocol_vstaging, PeerId,
 };
 use polkadot_primitives::{AuthorityDiscoveryId, Block, Hash};
 
-use crate::validator_discovery::AuthorityDiscovery;
+use crate::{metrics::Metrics, validator_discovery::AuthorityDiscovery, WireMessage};
 
 // network bridge network abstraction log target
 const LOG_TARGET: &'static str = "parachain::network-bridge-net";
 
-/// Send a message to the network.
+// Helper function to send a validation v1 message to a list of peers.
+// Messages are always sent via the main protocol, even legacy protocol messages.
+pub(crate) fn send_validation_message_v1(
+	net: &mut impl Network,
+	peers: Vec<PeerId>,
+	peerset_protocol_names: &PeerSetProtocolNames,
+	message: WireMessage<protocol_v1::ValidationProtocol>,
+	metrics: &Metrics,
+) {
+	gum::trace!(target: LOG_TARGET, ?peers, ?message, "Sending validation v1 message to peers",);
+
+	send_message(
+		net,
+		peers,
+		PeerSet::Validation,
+		ValidationVersion::V1.into(),
+		peerset_protocol_names,
+		message,
+		metrics,
+	);
+}
+
+// Helper function to send a validation vstaging message to a list of peers.
+// Messages are always sent via the main protocol, even legacy protocol messages.
+pub(crate) fn send_validation_message_vstaging(
+	net: &mut impl Network,
+	peers: Vec<PeerId>,
+	peerset_protocol_names: &PeerSetProtocolNames,
+	message: WireMessage<protocol_vstaging::ValidationProtocol>,
+	metrics: &Metrics,
+) {
+	gum::trace!(target: LOG_TARGET, ?peers, ?message, "Sending validation vstaging message to peers",);
+
+	send_message(
+		net,
+		peers,
+		PeerSet::Validation,
+		ValidationVersion::VStaging.into(),
+		peerset_protocol_names,
+		message,
+		metrics,
+	);
+}
+
+// Helper function to send a validation v2 message to a list of peers.
+// Messages are always sent via the main protocol, even legacy protocol messages.
+pub(crate) fn send_validation_message_v2(
+	net: &mut impl Network,
+	peers: Vec<PeerId>,
+	protocol_names: &PeerSetProtocolNames,
+	message: WireMessage<protocol_v2::ValidationProtocol>,
+	metrics: &Metrics,
+) {
+	send_message(
+		net,
+		peers,
+		PeerSet::Validation,
+		ValidationVersion::V2.into(),
+		protocol_names,
+		message,
+		metrics,
+	);
+}
+
+// Helper function to send a collation v1 message to a list of peers.
+// Messages are always sent via the main protocol, even legacy protocol messages.
+pub(crate) fn send_collation_message_v1(
+	net: &mut impl Network,
+	peers: Vec<PeerId>,
+	peerset_protocol_names: &PeerSetProtocolNames,
+	message: WireMessage<protocol_v1::CollationProtocol>,
+	metrics: &Metrics,
+) {
+	send_message(
+		net,
+		peers,
+		PeerSet::Collation,
+		CollationVersion::V1.into(),
+		peerset_protocol_names,
+		message,
+		metrics,
+	);
+}
+
+// Helper function to send a collation v2 message to a list of peers.
+// Messages are always sent via the main protocol, even legacy protocol messages.
+pub(crate) fn send_collation_message_v2(
+	net: &mut impl Network,
+	peers: Vec<PeerId>,
+	peerset_protocol_names: &PeerSetProtocolNames,
+	message: WireMessage<protocol_v2::CollationProtocol>,
+	metrics: &Metrics,
+) {
+	send_message(
+		net,
+		peers,
+		PeerSet::Collation,
+		CollationVersion::V2.into(),
+		peerset_protocol_names,
+		message,
+		metrics,
+	);
+}
+
+/// Lower level function that sends a message to the network using the main protocol version.
 ///
 /// This function is only used internally by the network-bridge, which is responsible to only send
 /// messages that are compatible with the passed peer set, as that is currently not enforced by
 /// this function. These are messages of type `WireMessage` parameterized on the matching type.
-pub(crate) fn send_message<M>(
+fn send_message<M>(
 	net: &mut impl Network,
 	mut peers: Vec<PeerId>,
 	peer_set: PeerSet,
@@ -65,6 +171,17 @@ pub(crate) fn send_message<M>(
 		encoded
 	};
 
+	// optimization: generate the protocol name once.
+	let protocol_name = protocol_names.get_name(peer_set, version);
+	gum::trace!(
+		target: LOG_TARGET,
+		?peers,
+		?version,
+		?protocol_name,
+		?message,
+		"Sending message to peers",
+	);
+
 	// optimization: avoid cloning the message for the last peer in the
 	// list. The message payload can be quite large. If the underlying
 	// network used `Bytes` this would not be necessary.