Random remote lookup port (#32)

* issue 15: implemented default config locations

* finished issue 15

* check config file exists before attempting read

* moved config loaded msg, removed config_file from DnsSettings

* removed commented code

* moved file read out of loop

* refactored into separate load functions so config param now optional

* second attempt

* will randomly generate remote lookup port

* removed unwanted debug line

---------

Co-authored-by: ghost <[email protected]>

dns.config.yaml

@@ -1,5 +1,4 @@
 listening-port: 53
-remote-lookup-port: 42069
 thread-count: 1
 use-udp: true
 use-tcp: false

src/dns_resolver.rs

@@ -6,14 +6,12 @@ use std::net::UdpSocket;
 
 pub struct DnsResolver {
   database: SimpleDatabase,
-  remote_lookup_port: u16,
 }
 
 impl DnsResolver {
-  pub fn new(database_file: String, remote_lookup_port: u16) -> DnsResolver {
+  pub fn new(database_file: String) -> DnsResolver {
     Self {
       database: SimpleDatabase::new(database_file),
-      remote_lookup_port,
     }
   }
 
@@ -66,7 +64,7 @@ impl DnsResolver {
   fn do_remote_lookup(&self, question: &DnsQuestion, packet: &mut DnsPacket) -> Result<(), Box<dyn Error>> {
     let server = (self.database.get_random_remote_lookup_server().unwrap(), 53);
 
-    let socket = UdpSocket::bind(("0.0.0.0", self.remote_lookup_port))?;
+    let socket = UdpSocket::bind(("0.0.0.0:0"))?;
 
     let mut remote_packet = DnsPacket::new();
     remote_packet.header.recurse_desired = true;

src/dns_server.rs

@@ -66,7 +66,7 @@ impl DnsServer for DnsUdpServer {
             };
 
             // process request
-            let resolver = DnsResolver::new(settings.database_file.clone(), settings.remote_lookup_port);
+            let resolver = DnsResolver::new(settings.database_file.clone());
 
             match resolver.answer_question(request_packet) {
               Ok(result) => {
@@ -155,7 +155,7 @@ impl DnsServer for DnsTcpServer {
           ignore_result_or_log_error_continue!(stream.read_to_end(&mut packet_buffer), "Failed to read the packet into a buffer");
 
           let request = return_result_or_log_error_continue!(DnsPacket::from_bytes(packet_buffer.as_slice()), "Failed to parse packet from buffer");
-          let resolver = DnsResolver::new(settings.database_file.clone(), settings.remote_lookup_port);
+          let resolver = DnsResolver::new(settings.database_file.clone());
 
           match resolver.answer_question(request) {
             Ok(result) => {

src/main.rs

@@ -139,7 +139,6 @@ fn main() -> Result<(), Box<dyn Error>> {
       };
       let settings = settings.expect("Error reading settings!");
       log_debug!("Settings: {:?}", settings);
-
       let server_udp = DnsUdpServer::new(settings.clone());
       let server_tcp = DnsTcpServer::new(settings.clone());
 

src/settings.rs

@@ -2,6 +2,9 @@ use std::error::Error;
 use std::fs;
 use std::io::ErrorKind;
 use yaml_rust::YamlLoader;
+use std::path::Path;
+
+use crate::log_info;
 
 use crate::log_debug;
 
@@ -10,7 +13,6 @@ extern crate shellexpand;
 #[derive(Clone, Debug)]
 pub struct DnsSettings {
   pub listening_port: u16,
-  pub remote_lookup_port: u16,
   pub database_file: String,
   pub thread_count: u32,
   pub use_udp: bool,
@@ -34,10 +36,6 @@ impl DnsSettings {
           Some(x) => x as u16,
           None => 53,
         };
-        let remote_lookup_port = match config_settings["remote-lookup-port"].as_i64() {
-          Some(x) => x as u16,
-          None => 42069,
-        };
         let thread_count = match config_settings["thread-count"].as_i64() {
           Some(x) => x as u32,
           None => 1, // TODO is this the best default?
@@ -61,7 +59,6 @@ impl DnsSettings {
 
         Ok(DnsSettings {
           listening_port,
-          remote_lookup_port,
           database_file,
           thread_count,
           use_udp,