Recursor: make nameserver and record cache sizes configurable

crates/recursor/src/recursor.rs

@@ -49,18 +49,19 @@ impl Recursor {
     /// # Panics
     ///
     /// This will panic if the roots are empty.
-    pub fn new(roots: impl Into<NameServerConfigGroup>) -> Result<Self, ResolveError> {
+    pub fn new(roots: impl Into<NameServerConfigGroup>, ns_cache_size: usize, record_cache_size: usize) -> Result<Self, ResolveError> {
         // configure the hickory-resolver
         let roots: NameServerConfigGroup = roots.into();
 
         assert!(!roots.is_empty(), "roots must not be empty");
 
+        debug!("Using cache sizes {}/{}", ns_cache_size, record_cache_size);
         let opts = recursor_opts();
         let roots =
             GenericNameServerPool::from_config(roots, opts, TokioConnectionProvider::default());
         let roots = RecursorPool::from(Name::root(), roots);
-        let name_server_cache = Mutex::new(NameServerCache::new(100)); // TODO: make this configurable
-        let record_cache = DnsLru::new(100, TtlConfig::default());
+        let name_server_cache = Mutex::new(NameServerCache::new(ns_cache_size));
+        let record_cache = DnsLru::new(record_cache_size, TtlConfig::default());
 
         Ok(Self {
             roots,
@@ -301,7 +302,6 @@ impl Recursor {
                     .into_iter()
                     .chain(r.take_name_servers())
                     .chain(r.take_additionals());
-
                 let lookup = self.record_cache.insert_records(query, records, now);
 
                 lookup.ok_or_else(|| Error::from("no records found"))

crates/server/src/store/recursor/authority.rs

@@ -74,7 +74,7 @@ impl RecursiveAuthority {
         }
 
         let recursor =
-            Recursor::new(roots).map_err(|e| format!("failed to initialize recursor: {e}"))?;
+            Recursor::new(roots, config.ns_cache_size, config.record_cache_size).map_err(|e| format!("failed to initialize recursor: {e}"))?;
 
         Ok(Self {
             origin: origin.into(),

crates/server/src/store/recursor/config.rs

@@ -27,6 +27,14 @@ use crate::resolver::Name;
 pub struct RecursiveConfig {
     /// File with roots, aka hints
     pub roots: PathBuf,
+
+    /// Maximum nameserver cache size
+    #[serde(default = "ns_cache_size_default")]
+    pub ns_cache_size: usize,
+
+    /// Maximum DNS record cache size
+    #[serde(default = "record_cache_size_default")]
+    pub record_cache_size: usize,
 }
 
 impl RecursiveConfig {
@@ -57,3 +65,6 @@ impl RecursiveConfig {
             .collect())
     }
 }
+
+fn ns_cache_size_default() -> usize { 1024 }
+fn record_cache_size_default() -> usize { 1048576 }

tests/test-data/test_configs/example_recursor.toml

@@ -37,4 +37,4 @@ zone_type = "Hint"
 
 ## remember the port, defaults: 53 for Udp & Tcp, 853 for Tls and 443 for Https.
 ##   Tls and/or Https require features dns-over-tls and/or dns-over-https
-stores = { type = "recursor", roots = "default/root.zone" }
+stores = { type = "recursor", roots = "default/root.zone", ns_cache_size = 1024, record_cache_size = 1048576 }

util/src/bin/recurse.rs

@@ -157,7 +157,7 @@ pub async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let name = opts.domainname;
     let ty = opts.ty;
 
-    let recursor = Recursor::new(roots)?;
+    let recursor = Recursor::new(roots, 1024, 1048576)?;
 
     // execute query
     println!(