1 files changed, 85 insertions, 0 deletions
diff --git a/src/dns/server.rs b/src/dns/server.rs
new file mode 100644
index 0000000..65d15df
--- /dev/null
+++ b/src/dns/server.rs
@@ -0,0 +1,85 @@
+use super::{
+    binding::Binding,
+    packet::{question::DnsQuestion, Packet},
+    resolver::Resolver,
+};
+use crate::{config::Config, database::Database, Result};
+use moka::future::Cache;
+use std::{net::SocketAddr, sync::Arc, time::Duration};
+use tokio::task::JoinHandle;
+use tracing::{error, info};
+
+pub struct DnsServer {
+    addr: SocketAddr,
+    config: Arc<Config>,
+    database: Arc<Database>,
+    cache: Cache<DnsQuestion, (Packet, u64)>,
+}
+
+impl DnsServer {
+    pub async fn new(config: Config, database: Database) -> Result<Self> {
+        let addr = format!("[::]:{}", config.dns_port).parse::<SocketAddr>()?;
+        let cache = Cache::builder()
+            .time_to_live(Duration::from_secs(60 * 60))
+            .max_capacity(config.dns_cache_size)
+            .build();
+
+        info!("Created DNS cache with size of {}", config.dns_cache_size);
+
+        Ok(Self {
+            addr,
+            config: Arc::new(config),
+            database: Arc::new(database),
+            cache,
+        })
+    }
+
+    pub async fn run(&self) -> Result<(JoinHandle<()>, JoinHandle<()>)> {
+        let tcp = Binding::tcp(self.addr).await?;
+        let tcp_handle = self.listen(tcp);
+
+        let udp = Binding::udp(self.addr).await?;
+        let udp_handle = self.listen(udp);
+
+        info!(
+            "Fallback DNS Server is set to: {:?}",
+            self.config.dns_fallback
+        );
+        info!(
+            "Listening for TCP and UDP traffic on [::]:{}",
+            self.config.dns_port
+        );
+
+        Ok((udp_handle, tcp_handle))
+    }
+
+    fn listen(&self, mut binding: Binding) -> JoinHandle<()> {
+        let config = self.config.clone();
+        let database = self.database.clone();
+        let cache = self.cache.clone();
+        tokio::spawn(async move {
+            let mut id = 0;
+            loop {
+                let Ok(connection) = binding.connect().await else { continue };
+                info!("Received request on {}", binding.name());
+
+                let resolver = Resolver::new(
+                    id,
+                    connection,
+                    config.clone(),
+                    database.clone(),
+                    cache.clone(),
+                );
+
+                let name = binding.name().to_string();
+                tokio::spawn(async move {
+                    if let Err(err) = resolver.handle_query().await {
+                        error!("{} request {} failed: {:?}", name, id, err);
+                    };
+                });
+
+                id += 1;
+            }
+        })
+    }
+}