Add a KeysInterface which provides keys from user

Move ChannelKeys into keysinterface for generate a set of it from
master_seed and change return type to panic on bogus data

src/chain/keysinterface.rs

@@ -5,7 +5,12 @@
 use bitcoin::blockdata::transaction::{OutPoint, TxOut};
 use bitcoin::blockdata::script::Script;
 
-use secp256k1::key::SecretKey;
+use secp256k1::key::{SecretKey, PublicKey};
+use secp256k1::Secp256k1;
+
+use crypto::hkdf::{hkdf_extract,hkdf_expand};
+
+use util::sha2::Sha256;
 
 /// When on-chain outputs are created by rust-lightning an event is generated which informs the
 /// user thereof. This enum describes the format of the output and provides the OutPoint.
@@ -34,3 +39,81 @@ pub enum SpendableOutputDescriptor {
 		to_self_delay: u16,
 	}
 }
+
+/// A trait to describe an object which can get user secrets and key material.
+pub trait KeysInterface: Send + Sync {
+	/// Get node secret key (aka node_id or network_key)
+	fn get_node_secret(&self) -> SecretKey;
+	/// Get destination redeemScript to encumber static protocol exit points.
+	fn get_destination_script(&self) -> Script;
+	/// Get shutdown_pubkey to use as PublicKey at channel closure
+	fn get_shutdown_pubkey(&self) -> PublicKey;
+	/// Get a new set of ChannelKeys for per-channel secrets. These MUST be unique even if you
+	/// restarted with some stale data!
+	fn get_channel_keys(&self, inbound: bool) -> ChannelKeys;
+}
+
+/// Set of lightning keys needed to operate a channel as described in BOLT 3
+pub struct ChannelKeys {
+	/// Private key of anchor tx
+	pub funding_key: SecretKey,
+	/// Local secret key for blinded revocation pubkey
+	pub revocation_base_key: SecretKey,
+	/// Local secret key used in commitment tx htlc outputs
+	pub payment_base_key: SecretKey,
+	/// Local secret key used in HTLC tx
+	pub delayed_payment_base_key: SecretKey,
+	/// Local htlc secret key used in commitment tx htlc outputs
+	pub htlc_base_key: SecretKey,
+	/// Local secret key used for closing tx
+	pub channel_close_key: SecretKey,
+	/// Local secret key used in justice tx, claim tx and preimage tx outputs
+	pub channel_monitor_claim_key: SecretKey,
+	/// Commitment seed
+	pub commitment_seed: [u8; 32],
+}
+
+impl ChannelKeys {
+	/// Generate a set of lightning keys needed to operate a channel by HKDF-expanding a given
+	/// random 32-byte seed
+	pub fn new_from_seed(seed: &[u8; 32]) -> ChannelKeys {
+		let mut prk = [0; 32];
+		hkdf_extract(Sha256::new(), b"rust-lightning key gen salt", seed, &mut prk);
+		let secp_ctx = Secp256k1::without_caps();
+
+		let mut okm = [0; 32];
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning funding key info", &mut okm);
+		let funding_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
+
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning revocation base key info", &mut okm);
+		let revocation_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
+
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning payment base key info", &mut okm);
+		let payment_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
+
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning delayed payment base key info", &mut okm);
+		let delayed_payment_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
+
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning htlc base key info", &mut okm);
+		let htlc_base_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
+
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning channel close key info", &mut okm);
+		let channel_close_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
+
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning channel monitor claim key info", &mut okm);
+		let channel_monitor_claim_key = SecretKey::from_slice(&secp_ctx, &okm).expect("Sha256 is broken");
+
+		hkdf_expand(Sha256::new(), &prk, b"rust-lightning local commitment seed info", &mut okm);
+
+		ChannelKeys {
+			funding_key: funding_key,
+			revocation_base_key: revocation_base_key,
+			payment_base_key: payment_base_key,
+			delayed_payment_base_key: delayed_payment_base_key,
+			htlc_base_key: htlc_base_key,
+			channel_close_key: channel_close_key,
+			channel_monitor_claim_key: channel_monitor_claim_key,
+			commitment_seed: okm
+		}
+	}
+}

src/ln/channel.rs

@@ -11,7 +11,6 @@ use secp256k1::{Secp256k1,Message,Signature};
 use secp256k1;
 
 use crypto::digest::Digest;
-use crypto::hkdf::{hkdf_extract,hkdf_expand};
 
 use ln::msgs;
 use ln::msgs::{ErrorAction, HandleError, RAACommitmentOrder};
@@ -21,6 +20,7 @@ use ln::chan_utils::{TxCreationKeys,HTLCOutputInCommitment,HTLC_SUCCESS_TX_WEIGH
 use ln::chan_utils;
 use chain::chaininterface::{FeeEstimator,ConfirmationTarget};
 use chain::transaction::OutPoint;
+use chain::keysinterface::ChannelKeys;
 use util::{transaction_utils,rng};
 use util::ser::Writeable;
 use util::sha2::Sha256;
@@ -33,17 +33,6 @@ use std::{cmp,mem};
 use std::time::Instant;
 use std::sync::{Arc};
 
-pub struct ChannelKeys {
-	pub funding_key: SecretKey,
-	pub revocation_base_key: SecretKey,
-	pub payment_base_key: SecretKey,
-	pub delayed_payment_base_key: SecretKey,
-	pub htlc_base_key: SecretKey,
-	pub channel_close_key: SecretKey,
-	pub channel_monitor_claim_key: SecretKey,
-	pub commitment_seed: [u8; 32],
-}
-
 #[cfg(test)]
 pub struct ChannelValueStat {
 	pub value_to_self_msat: u64,
@@ -55,49 +44,6 @@ pub struct ChannelValueStat {
 	pub their_max_htlc_value_in_flight_msat: u64, // outgoing
 }
 
-impl ChannelKeys {
-	pub fn new_from_seed(seed: &[u8; 32]) -> Result<ChannelKeys, secp256k1::Error> {
-		let mut prk = [0; 32];
-		hkdf_extract(Sha256::new(), b"rust-lightning key gen salt", seed, &mut prk);
-		let secp_ctx = Secp256k1::without_caps();
-
-		let mut okm = [0; 32];
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning funding key info", &mut okm);
-		let funding_key = SecretKey::from_slice(&secp_ctx, &okm)?;
-
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning revocation base key info", &mut okm);
-		let revocation_base_key = SecretKey::from_slice(&secp_ctx, &okm)?;
-
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning payment base key info", &mut okm);
-		let payment_base_key = SecretKey::from_slice(&secp_ctx, &okm)?;
-
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning delayed payment base key info", &mut okm);
-		let delayed_payment_base_key = SecretKey::from_slice(&secp_ctx, &okm)?;
-
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning htlc base key info", &mut okm);
-		let htlc_base_key = SecretKey::from_slice(&secp_ctx, &okm)?;
-
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning channel close key info", &mut okm);
-		let channel_close_key = SecretKey::from_slice(&secp_ctx, &okm)?;
-
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning channel monitor claim key info", &mut okm);
-		let channel_monitor_claim_key = SecretKey::from_slice(&secp_ctx, &okm)?;
-
-		hkdf_expand(Sha256::new(), &prk, b"rust-lightning local commitment seed info", &mut okm);
-
-		Ok(ChannelKeys {
-			funding_key: funding_key,
-			revocation_base_key: revocation_base_key,
-			payment_base_key: payment_base_key,
-			delayed_payment_base_key: delayed_payment_base_key,
-			htlc_base_key: htlc_base_key,
-			channel_close_key: channel_close_key,
-			channel_monitor_claim_key: channel_monitor_claim_key,
-			commitment_seed: okm
-		})
-	}
-}
-
 enum InboundHTLCRemovalReason {
 	FailRelay(msgs::OnionErrorPacket),
 	FailMalformed(([u8; 32], u16)),

src/ln/channelmanager.rs

@@ -22,11 +22,12 @@ use secp256k1;
 
 use chain::chaininterface::{BroadcasterInterface,ChainListener,ChainWatchInterface,FeeEstimator};
 use chain::transaction::OutPoint;
-use ln::channel::{Channel, ChannelError, ChannelKeys};
+use ln::channel::{Channel, ChannelError};
 use ln::channelmonitor::{ChannelMonitorUpdateErr, ManyChannelMonitor, CLTV_CLAIM_BUFFER, HTLC_FAIL_TIMEOUT_BLOCKS};
 use ln::router::{Route,RouteHop};
 use ln::msgs;
 use ln::msgs::{ChannelMessageHandler, HandleError, RAACommitmentOrder};
+use chain::keysinterface::ChannelKeys;
 use util::{byte_utils, events, internal_traits, rng};
 use util::sha2::Sha256;
 use util::ser::{Readable, Writeable};
@@ -432,10 +433,7 @@ impl ChannelManager {
 		} else {
 			let mut key_seed = [0u8; 32];
 			rng::fill_bytes(&mut key_seed);
-			match ChannelKeys::new_from_seed(&key_seed) {
-				Ok(key) => key,
-				Err(_) => panic!("RNG is busted!")
-			}
+			ChannelKeys::new_from_seed(&key_seed)
 		};
 
 		let channel = Channel::new_outbound(&*self.fee_estimator, chan_keys, their_network_key, channel_value_satoshis, push_msat, self.announce_channels_publicly, user_id, Arc::clone(&self.logger))?;
@@ -1689,10 +1687,7 @@ impl ChannelManager {
 		} else {
 			let mut key_seed = [0u8; 32];
 			rng::fill_bytes(&mut key_seed);
-			match ChannelKeys::new_from_seed(&key_seed) {
-				Ok(key) => key,
-				Err(_) => panic!("RNG is busted!")
-			}
+			ChannelKeys::new_from_seed(&key_seed)
 		};
 
 		let channel = Channel::new_from_req(&*self.fee_estimator, chan_keys, their_node_id.clone(), msg, 0, false, self.announce_channels_publicly, Arc::clone(&self.logger))