add authority discovery module (#444)

polkadot/runtime/src/lib.rs

@@ -55,7 +55,8 @@ use sr_staking_primitives::SessionIndex;
 use srml_support::{
 	parameter_types, construct_runtime, traits::{SplitTwoWays, Currency}
 };
-use im_online::sr25519::{AuthorityId as ImOnlineId};
+use authority_discovery_primitives::{AuthorityId as EncodedAuthorityId, Signature as EncodedSignature};
+use im_online::sr25519::{AuthorityId as ImOnlineId, AuthoritySignature as ImOnlineSignature};
 use system::offchain::TransactionSubmitter;
 
 #[cfg(feature = "std")]
@@ -242,7 +243,7 @@ parameter_types! {
 	pub const Offset: BlockNumber = 0;
 }
 
-type SessionHandlers = (Grandpa, Babe, ImOnline, Parachains);
+type SessionHandlers = (Grandpa, Babe, ImOnline, AuthorityDiscovery, Parachains);
 impl_opaque_keys! {
 	pub struct SessionKeys {
 		#[id(key_types::GRANDPA)]
@@ -444,6 +445,8 @@ impl im_online::Trait for Runtime {
 	type ReportUnresponsiveness = ();
 }
 
+impl authority_discovery::Trait for Runtime {}
+
 impl grandpa::Trait for Runtime {
 	type Event = Event;
 }
@@ -530,6 +533,7 @@ construct_runtime!(
 		FinalityTracker: finality_tracker::{Module, Call, Inherent},
 		Grandpa: grandpa::{Module, Call, Storage, Config, Event},
 		ImOnline: im_online::{Module, Call, Storage, Event<T>, ValidateUnsigned, Config<T>},
+		AuthorityDiscovery: authority_discovery::{Module, Call, Config<T>},
 
 		// Governance stuff; uncallable initially.
 		Democracy: democracy::{Module, Call, Storage, Config, Event<T>},
@@ -684,6 +688,35 @@ impl_runtime_apis! {
 		}
 	}
 
+	impl authority_discovery_primitives::AuthorityDiscoveryApi<Block> for Runtime {
+		fn authorities() -> Vec<EncodedAuthorityId> {
+			AuthorityDiscovery::authorities().into_iter()
+				.map(|id| id.encode())
+				.map(EncodedAuthorityId)
+				.collect()
+		}
+
+		fn sign(payload: &Vec<u8>) -> Option<(EncodedSignature, EncodedAuthorityId)> {
+			AuthorityDiscovery::sign(payload).map(|(sig, id)| {
+				(EncodedSignature(sig.encode()), EncodedAuthorityId(id.encode()))
+			})
+		}
+
+		fn verify(payload: &Vec<u8>, signature: &EncodedSignature, authority_id: &EncodedAuthorityId) -> bool {
+			let signature = match ImOnlineSignature::decode(&mut &signature.0[..]) {
+				Ok(s) => s,
+				_ => return false,
+			};
+
+			let authority_id = match ImOnlineId::decode(&mut &authority_id.0[..]) {
+				Ok(id) => id,
+				_ => return false,
+			};
+
+			AuthorityDiscovery::verify(payload, signature, authority_id)
+		}
+	}
+
 	impl substrate_session::SessionKeys<Block> for Runtime {
 		fn generate_session_keys(seed: Option<Vec<u8>>) -> Vec<u8> {
 			let seed = seed.as_ref().map(|s| rstd::str::from_utf8(&s).expect("Seed is an utf8 string"));