*: Refactor authority discovery (key mngmt, runtime API) (#3955)

* {core,srml}/authority-discovery: Move generic to specific session keys

* {srml,core}/authority-discovery: Verify signature outside of runtime

Given that the `core/authority-discovery` uses concrete authority
identifiers and signatures, one can verify a signature with the
authority discovery within `core`. Given the above, the `verify` runtime
api is obsolete and thus removed.

* *: Add authority discovery to the set of session keys

* *: Sign authority discovery DHT payload with keystore instead of runtime

Instead of calling a runtime function to sign a dht payload, which then
invokes the keystore, pass the keystore to the authority discovery
module and use it directly.

* core/authority-discovery: Give libp2p Kademlia time to start up

* core/authority-discovery: Move authorities priority group name to const

* node/runtime/src/lib.rs: Bump runtime spec version

* *: Fix lints and node/testing test failures

* *: Fix formatting

* core/authority-discovery: Box dht event channel in unit tests

* node/cli/src/service.rs: Fix future import

* node/cli/src/service.rs: Replace unwrap by expect with proof

* node/cli/src/chain_spec: Remove TODO for testnet key generation

* core/authority-discovery/src/lib: Remove scale encoding TODOs

* srml/authority-discovery: Make comment a doc comment

* core/authority-discovery: Remove unused StreamExt import

* node/runtime: Bump impl version to debug CI

* Test ci.

* Change the line width to 100.

* Revert "Change the line width to 100."

This reverts commit edff1f8.

* Fix a check for polkadot to work on forked repos.

* Revert "node/runtime: Bump impl version to debug CI"

This reverts commit 1a90903.

* Revert "Test ci."

This reverts commit a2c9df5.

* Cargo.lock: Fix wrong lock file merge

* srml/authority-discovery: Keep track of new validator set not upcoming

* core/authority-discovery: Document key retrieval functions

core/authority-discovery/Cargo.toml

@@ -15,14 +15,15 @@ client = { package = "substrate-client", path = "../../core/client" }
 codec = { package = "parity-scale-codec", default-features = false, version = "1.0.3" }
 derive_more = "0.15.0"
 futures-preview = "0.3.0-alpha.19"
+futures-timer = "0.4"
+keystore = { package = "substrate-keystore", path = "../keystore" }
 libp2p = { version = "0.13.0", default-features = false, features = ["secp256k1", "libp2p-websocket"] }
 log = "0.4.8"
 network = { package = "substrate-network", path = "../../core/network" }
 primitives = { package = "substrate-primitives", path = "../primitives" }
 prost = "0.5.0"
 serde_json = "1.0.41"
 sr-primitives = { path = "../../core/sr-primitives" }
-futures-timer = "0.4"
 
 [dev-dependencies]
 parking_lot = "0.9.0"

core/authority-discovery/primitives/Cargo.toml

@@ -6,14 +6,16 @@ description = "Authority discovery primitives"
 edition = "2018"
 
 [dependencies]
+app-crypto = { package = "substrate-application-crypto", path = "../../application-crypto", default-features = false }
 codec = { package = "parity-scale-codec", default-features = false, version = "1.0.3" }
+rstd = { package = "sr-std", path = "../../sr-std", default-features = false }
 sr-api = { path = "../../sr-api", default-features = false }
 sr-primitives = { path = "../../sr-primitives", default-features = false }
-rstd = { package = "sr-std", path = "../../sr-std", default-features = false }
 
 [features]
 default = ["std"]
 std = [
+	"app-crypto/std",
 	"rstd/std",
 	"sr-api/std",
 	"codec/std",

core/authority-discovery/primitives/src/lib.rs

@@ -19,31 +19,28 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use rstd::vec::Vec;
-use sr_primitives::RuntimeDebug;
 
-#[derive(codec::Encode, codec::Decode, Eq, PartialEq, Clone, RuntimeDebug)]
-#[cfg_attr(feature = "std", derive(Hash))]
-pub struct Signature(pub Vec<u8>);
-#[derive(codec::Encode, codec::Decode, Eq, PartialEq, Clone, RuntimeDebug)]
-#[cfg_attr(feature = "std", derive(Hash))]
-pub struct AuthorityId(pub Vec<u8>);
+mod app {
+	use app_crypto::{app_crypto, key_types::AUTHORITY_DISCOVERY, sr25519};
+	app_crypto!(sr25519, AUTHORITY_DISCOVERY);
+}
+
+/// An authority discovery authority keypair.
+#[cfg(feature = "std")]
+pub type AuthorityPair = app::Pair;
+
+/// An authority discovery authority identifier.
+pub type AuthorityId = app::Public;
+
+/// An authority discovery authority signature.
+pub type AuthoritySignature = app::Signature;
 
 sr_api::decl_runtime_apis! {
 	/// The authority discovery api.
 	///
-	/// This api is used by the `core/authority-discovery` module to retrieve our
-	/// own authority identifier, to retrieve identifiers of the current authority
-	/// set, as well as sign and verify Kademlia Dht external address payloads
-	/// from and to other authorities.
+	/// This api is used by the `core/authority-discovery` module to retrieve identifiers of the current authority set.
 	pub trait AuthorityDiscoveryApi {
 		/// Retrieve authority identifiers of the current authority set.
 		fn authorities() -> Vec<AuthorityId>;
-
-		/// Sign the given payload with the private key corresponding to the given authority id.
-		fn sign(payload: &Vec<u8>) -> Option<(Signature, AuthorityId)>;
-
-		/// Verify the given signature for the given payload with the given
-		/// authority identifier.
-		fn verify(payload: &Vec<u8>, signature: &Signature, authority_id: &AuthorityId) -> bool;
 	}
 }

core/authority-discovery/src/error.rs

@@ -28,18 +28,18 @@ pub enum Error {
 	HashingAuthorityId(libp2p::core::multiaddr::multihash::EncodeError),
 	/// Failed calling into the Substrate runtime.
 	CallingRuntime(client::error::Error),
-	/// Failed signing the dht payload via the Substrate runtime.
-	SigningDhtPayload,
 	/// From the Dht we only get the hashed authority id. In order to retrieve the actual authority id and to ensure it
 	/// is actually an authority, we match the hash against the hash of the authority id of all other authorities. This
 	/// error is the result of the above failing.
 	MatchingHashedAuthorityIdWithAuthorityId,
 	/// Failed to set the authority discovery peerset priority group in the peerset module.
 	SettingPeersetPriorityGroup(String),
-	/// Failed to encode a dht payload.
-	Encoding(prost::EncodeError),
-	/// Failed to decode a dht payload.
-	Decoding(prost::DecodeError),
+	/// Failed to encode a protobuf payload.
+	EncodingProto(prost::EncodeError),
+	/// Failed to decode a protobuf payload.
+	DecodingProto(prost::DecodeError),
+	/// Failed to encode or decode scale payload
+	EncodingDecodingScale(codec::Error),
 	/// Failed to parse a libp2p multi address.
 	ParsingMultiaddress(libp2p::core::multiaddr::Error),
 }