Transaction broadcast (#209)

* Add transaction broadcast to all known peers once they have been
accepted by our own transaction pool.
* Some debug log

Fixes #200

p2p/src/peer.rs

@@ -139,6 +139,13 @@ impl Peer {
 		self.proto.send_block(b)
 	}
 
+	/// Sends the provided transaction to the remote peer. The request may be
+	/// dropped if the remote peer is known to already have the transaction.
+	pub fn send_transaction(&self, tx: &core::Transaction) -> Result<(), Error> {
+		// TODO do not send if the peer sent us the tx in the first place
+		self.proto.send_transaction(tx)
+	}
+
 	pub fn send_header_request(&self, locator: Vec<Hash>) -> Result<(), Error> {
 		self.proto.send_header_request(locator)
 	}

p2p/src/server.rs

@@ -270,6 +270,20 @@ impl Server {
 		}
 	}
 
+	/// Broadcasts the provided transaction to all our peers. A peer
+	/// implementation may drop the broadcast request if it knows the
+	/// remote peer already has the transaction.
+	pub fn broadcast_transaction(&self, tx: &core::Transaction) {
+		let peers = self.peers.write().unwrap();
+		for p in peers.deref() {
+			if p.is_connected() {
+				if let Err(e) = p.send_transaction(tx) {
+					debug!(LOGGER, "Error sending block to peer: {:?}", e);
+				}
+			}
+		}
+	}
+
 	/// Number of peers we're currently connected to.
 	pub fn peer_count(&self) -> u32 {
 		self.peers.read().unwrap().len() as u32