Banning of misbehaving peer, applied to bad blocks

Added support for peer banning on the p2p server. The peer status
is changed and the peer is disconnected. A banned peer won't be
able to reconnect as well.

Tracking of chain errors due to a block that's intrinsically bad
and banning of the peer that sent it. If we're syncing, resetting
the header chain to the same as the main chain to force
backtracking.

chain/src/chain.rs

@@ -287,6 +287,17 @@ impl Chain {
 		sumtrees.roots()
 	}
 
+	/// Reset the header head to the same as the main head. When sync is running,
+	/// the header head will go ahead to try to download as many as possible.
+	/// However if a block, when fully received, is found invalid, the header
+	/// head need to backtrack to the last known valid position.
+	pub fn reset_header_head(&self) -> Result<(), Error> {
+		let head = self.head.lock().unwrap();
+		debug!(LOGGER, "Reset header head to {} at {}",
+					head.last_block_h, head.height);
+		self.store.save_header_head(&head).map_err(From::from)
+	}
+
 	/// returns the last n nodes inserted into the utxo sum tree
 	/// returns sum tree hash plus output itself (as the sum is contained
 	/// in the output anyhow)

chain/src/types.rs

@@ -100,6 +100,23 @@ impl From<io::Error> for Error {
 	}
 }
 
+impl Error {
+	/// Whether the error is due to a block that was intrinsically wrong
+	pub fn is_bad_block(&self) -> bool {
+		// shorter to match on all the "not the block's fault" errors
+		match *self {
+			Error::Unfit(_) |
+				Error::Orphan |
+				Error::StoreErr(_, _) |
+				Error::SerErr(_) |
+				Error::SumTreeErr(_)|
+				Error::GenesisBlockRequired |
+				Error::Other(_) => false,
+			_ => true,
+		}
+	}
+}
+
 /// The tip of a fork. A handle to the fork ancestry from its leaf in the
 /// blockchain tree. References the max height and the latest and previous
 /// blocks

grin/src/adapters.rs

@@ -61,7 +61,7 @@ impl NetAdapter for NetToChainAdapter {
 		}
 	}
 
-	fn block_received(&self, b: core::Block) {
+	fn block_received(&self, b: core::Block, addr: SocketAddr) {
 		let bhash = b.hash();
 		debug!(
 			LOGGER,
@@ -75,6 +75,18 @@ impl NetAdapter for NetToChainAdapter {
 
 		if let &Err(ref e) = &res {
 			debug!(LOGGER, "Block {} refused by chain: {:?}", bhash, e);
+
+			// if the peer sent us a block that's intrinsically bad, they're either
+			// mistaken or manevolent, both of which require a ban
+			if e.is_bad_block() {
+				self.p2p_server.borrow().ban_peer(&addr);
+
+				// and if we're currently syncing, our header chain is now wrong, it
+				// needs to be reset
+				if self.is_syncing() {
+					self.chain.reset_header_head();
+				}
+			}
 		}
 	}
 

grin/src/seed.rs

@@ -93,21 +93,8 @@ impl Seeder {
 					p2p_server.all_peers().len(),
 				);
 
-				// maintenance step first, clean up p2p server peers and mark bans
-				// if needed
-				let disconnected = p2p_server.clean_peers();
-				for p in disconnected {
-					let p = p.read().unwrap();
-					if p.is_banned() {
-						debug!(LOGGER, "Marking peer {} as banned.", p.info.addr);
-						let update_result =
-							p2p_server.update_state(p.info.addr, p2p::State::Banned);
-						match update_result {
-							Ok(()) => {}
-							Err(_) => {}
-						}
-					}
-				}
+				// maintenance step first, clean up p2p server peers
+				let _ = p2p_server.clean_peers();
 
 				// we don't have enough peers, getting more from db
 				if p2p_server.peer_count() < PEER_PREFERRED_COUNT {

p2p/src/peer.rs

@@ -129,6 +129,12 @@ impl Peer {
 		*state == State::Banned
 	}
 
+	/// Set this peer status to banned
+	pub fn set_banned(&self) {
+		let mut state = self.state.write().unwrap();
+		*state = State::Banned;
+	}
+
 	/// Bytes sent and received by this peer to the remote peer.
 	pub fn transmitted_bytes(&self) -> (u64, u64) {
 		self.proto.transmitted_bytes()
@@ -224,9 +230,9 @@ impl NetAdapter for TrackingAdapter {
 		self.adapter.transaction_received(tx)
 	}
 
-	fn block_received(&self, b: core::Block) {
+	fn block_received(&self, b: core::Block, addr: SocketAddr) {
 		self.push(b.hash());
-		self.adapter.block_received(b)
+		self.adapter.block_received(b, addr)
 	}
 
 	fn headers_received(&self, bh: Vec<core::BlockHeader>, addr: SocketAddr) {

p2p/src/protocol.rs

@@ -185,7 +185,7 @@ fn handle_payload(
 		Type::Block => {
 			let b = ser::deserialize::<core::Block>(&mut &buf[..])?;
 			let bh = b.hash();
-			adapter.block_received(b);
+			adapter.block_received(b, addr);
 			Ok(Some(bh))
 		}
 		Type::GetHeaders => {

p2p/src/server.rs

@@ -17,7 +17,7 @@
 
 use std::cell::RefCell;
 use std::collections::HashMap;
-use std::net::SocketAddr;
+use std::net::{SocketAddr, Shutdown};
 use std::sync::{Arc, RwLock};
 use std::time::Duration;
 
@@ -45,8 +45,8 @@ impl NetAdapter for DummyAdapter {
 		Difficulty::one()
 	}
 	fn transaction_received(&self, _: core::Transaction) {}
-	fn block_received(&self, _: core::Block) {}
-	fn headers_received(&self, _: Vec<core::BlockHeader>, _: SocketAddr) {}
+	fn block_received(&self, _: core::Block, _: SocketAddr) {}
+	fn headers_received(&self, _: Vec<core::BlockHeader>, _:SocketAddr) {}
 	fn locate_headers(&self, _: Vec<Hash>) -> Vec<core::BlockHeader> {
 		vec![]
 	}
@@ -108,10 +108,35 @@ impl Server {
 		let peers = self.peers.clone();
 		let adapter = self.adapter.clone();
 		let capab = self.capabilities.clone();
+		let store = self.store.clone();
 
 		// main peer acceptance future handling handshake
 		let hp = h.clone();
 		let peers_listen = socket.incoming().map_err(From::from).map(move |(conn, _)| {
+	
+			// aaaand.. reclone for the internal closures
+			let adapter = adapter.clone();
+			let store = store.clone();
+			let peers = peers.clone();
+			let handshake = handshake.clone();
+			let hp = hp.clone();
+
+			future::ok(conn).and_then(move |conn| {
+				// Refuse banned peers connection
+				if let Ok(peer_addr) = conn.peer_addr() {
+					if let Ok(peer_data) = store.get_peer(peer_addr) {
+						if peer_data.flags == State::Banned {
+							debug!(LOGGER, "Peer {} banned, refusing connection.", peer_addr);
+							if let Err(e) = conn.shutdown(Shutdown::Both) {
+								debug!(LOGGER, "Error shutting down conn: {:?}", e);
+							}
+							return Err(Error::Banned)
+						}
+					}
+				}
+				Ok(conn)
+			}).and_then(move |conn| {
+
 				let peers = peers.clone();
 				let total_diff = adapter.total_difficulty();
 
@@ -133,6 +158,7 @@ impl Server {
 					let peer = peer.read().unwrap();
 					peer.run(conn)
 				})
+			})
 		});
 
 		// spawn each peer future to its own task
@@ -254,7 +280,7 @@ impl Server {
 		// build a list of peers to be cleaned up
 		for peer in self.connected_peers() {
 			let peer_inner = peer.read().unwrap();
-			if !peer_inner.is_connected() {
+			if peer_inner.is_banned() || !peer_inner.is_connected() {
 				debug!(LOGGER, "cleaning {:?}, not connected", peer_inner.info.addr);
 				rm.push(peer.clone());
 			}
@@ -350,6 +376,21 @@ impl Server {
 		self.connected_peers().len() as u32
 	}
 
+	/// Bans a peer, disconnecting it if we're currently connected
+	pub fn ban_peer(&self, peer_addr: &SocketAddr) {
+		if let Err(e) = self.update_state(peer_addr.clone(), State::Banned) {
+			error!(LOGGER, "Couldn't ban {}: {:?}", peer_addr, e);
+		}
+
+		if let Some(peer) = self.get_peer(peer_addr) {
+			debug!(LOGGER, "Banning peer {}", peer_addr);
+			// setting peer status will get it removed at the next clean_peer
+			let peer = peer.write().unwrap();
+			peer.set_banned();
+			peer.stop();
+		}
+	}
+
 	/// Stops the server. Disconnect from all peers at the same time.
 	pub fn stop(self) {
 		info!(LOGGER, "calling stop on server");

p2p/src/store.rs

@@ -98,24 +98,19 @@ impl PeerStore {
 	pub fn save_peer(&self, p: &PeerData) -> Result<(), Error> {
 		debug!(LOGGER, "saving peer to store {:?}", p);
 
-		self.db.put_ser(
-			&to_key(PEER_PREFIX, &mut format!("{}", p.addr).into_bytes())[..],
-			p,
-		)
+		self.db.put_ser(&peer_key(p.addr)[..], p)
 	}
 
-	fn get_peer(&self, peer_addr: SocketAddr) -> Result<PeerData, Error> {
+	pub fn get_peer(&self, peer_addr: SocketAddr) -> Result<PeerData, Error> {
 		option_to_not_found(self.db.get_ser(&peer_key(peer_addr)[..]))
 	}
 
 	pub fn exists_peer(&self, peer_addr: SocketAddr) -> Result<bool, Error> {
-		self.db
-			.exists(&to_key(PEER_PREFIX, &mut format!("{}", peer_addr).into_bytes())[..])
+		self.db.exists(&peer_key(peer_addr)[..])
 	}
 
 	pub fn delete_peer(&self, peer_addr: SocketAddr) -> Result<(), Error> {
-		self.db
-			.delete(&to_key(PEER_PREFIX, &mut format!("{}", peer_addr).into_bytes())[..])
+		self.db.delete(&peer_key(peer_addr)[..])
 	}
 
 	pub fn find_peers(&self, state: State, cap: Capabilities, count: usize) -> Vec<PeerData> {
@@ -148,5 +143,5 @@ impl PeerStore {
 }
 
 fn peer_key(peer_addr: SocketAddr) -> Vec<u8> {
-	to_key(PEER_PREFIX, &mut format!("{}", peer_addr).into_bytes())
+	to_key(PEER_PREFIX, &mut format!("{}", peer_addr.ip()).into_bytes())
 }

p2p/src/types.rs

@@ -41,6 +41,7 @@ pub const MAX_PEER_ADDRS: u32 = 256;
 pub enum Error {
 	Serialization(ser::Error),
 	Connection(io::Error),
+	Banned,
 	ConnectionClose,
 	Timeout,
 	Store(grin_store::Error),
@@ -169,7 +170,7 @@ pub trait NetAdapter: Sync + Send {
 	fn transaction_received(&self, tx: core::Transaction);
 
 	/// A block has been received from one of our peers
-	fn block_received(&self, b: core::Block);
+	fn block_received(&self, b: core::Block, addr: SocketAddr);
 
 	/// A set of block header has been received, typically in response to a
 	/// block