CLI option and network configuration

parity/cli.rs

@@ -67,6 +67,9 @@ Networking Options:
   --no-discovery           Disable new peer discovery.
   --node-key KEY           Specify node secret key, either as 64-character hex
                            string or input to SHA3 operation.
+  --reserved-peers FILE    Provide a file containing enodes, one per line.
+                           These nodes will always have a reserved slot on top
+                           of the normal maximum peers.
 
 API and Console Options:
   --jsonrpc-off            Disable the JSON-RPC API server.
@@ -236,6 +239,7 @@ pub struct Args {
 	pub flag_no_discovery: bool,
 	pub flag_nat: String,
 	pub flag_node_key: Option<String>,
+  pub flag_reserved_peers: Option<String>,
 	pub flag_cache_pref_size: usize,
 	pub flag_cache_max_size: usize,
 	pub flag_queue_max_size: usize,

parity/configuration.rs

@@ -153,6 +153,24 @@ impl Configuration {
 		}
 	}
 
+	pub fn init_reserved_nodes(&self) -> Vec<String> {
+		use std::fs::File;
+		use std::io::BufRead;
+
+		if let Some(ref path) = self.args.reserved_nodes {
+			let node_file = File::open(path).unwrap_or_else(|e| {
+				die!("Error opening reserved nodes file: {}", e);
+			});
+			node_file.lines().map(|s| {
+				Self::normalize_enode(s).unwrap_or_else(|| {
+					die!("{}: Invalid node address format given for a reserved node.", s);
+				})
+			}).collect()
+		} else {
+			Vec::new()
+		}
+	}
+
 	pub fn net_addresses(&self) -> (Option<SocketAddr>, Option<SocketAddr>) {
 		let port = self.net_port();
 		let listen_address = Some(SocketAddr::new(IpAddr::from_str("0.0.0.0").unwrap(), port));
@@ -179,6 +197,7 @@ impl Configuration {
 		let mut net_path = PathBuf::from(&self.path());
 		net_path.push("network");
 		ret.config_path = Some(net_path.to_str().unwrap().to_owned());
+		ret.reserved_nodes = self.init_reserved_nodes();
 		ret
 	}
 

util/src/network/host.rs

@@ -73,6 +73,8 @@ pub struct NetworkConfiguration {
 	pub use_secret: Option<Secret>,
 	/// Number of connected peers to maintain
 	pub ideal_peers: u32,
+	/// List of reserved node addresses.
+	pub reserved_nodes: Vec<String>,
 }
 
 impl Default for NetworkConfiguration {