fix: msg id conflict check

README.md

@@ -25,10 +25,12 @@ a DNS server in Rust, which is inspired from chinadns/dnsmasq.
 ZeroDNS provides similar functionality to dig, but supports more DNS protocols. Here are some examples:
 
 ```shell
-$ # Simple resolve, will read dns server from /etc/resolv.conf
+$ # Simple resolve, will read nameserver from /etc/resolv.conf
 $ zerodns resolve www.youtube.com
 $ # Use short output, similar with 'dig +short ...'
 $ zerodns resolve --short www.youtube.com
+$ # Resolve over google UDP
+$ zerodns resolve -s 8.8.8.8 www.youtube.com
 $ # Resolve over google TCP
 $ zerodns resolve -s tcp://8.8.8.8 www.youtube.com
 $ # Resolve over google DoT

src/client/udp.rs

@@ -173,28 +173,51 @@ impl MultiplexUdpClient {
 
     async fn request(
         &self,
-        req: Message,
+        req: &Message,
         remote: SocketAddr,
         timeout: Duration,
     ) -> Result<Message> {
-        let id = req.id();
+        let origin_id = req.id();
+        let mut id = origin_id;
 
         let (tx, rx) = oneshot::channel::<Message>();
         {
             let mut w = self.handlers.lock().await;
+            if w.contains_key(&(id, remote)) {
+                // TODO: how to check id conflict???
+                for seq in 1..u16::MAX {
+                    let key = (seq, remote);
+                    if !w.contains_key(&key) {
+                        id = seq;
+                        break;
+                    }
+                }
+            }
+
             w.insert((id, remote), tx);
         }
 
-        let res: Result<Message> = async move {
-            self.queue.send((req, remote)).await?;
+        let mut cloned_req = Clone::clone(req);
+        if origin_id != id {
+            cloned_req.set_id(id);
+        }
+        let mut res: Result<Message> = async move {
+            self.queue.send((cloned_req, remote)).await?;
             let res = tokio::time::timeout(timeout, rx).await??;
             Ok(res)
         }
         .await;
 
         // clean handler if enqueue failed
-        if res.is_err() {
-            self.handlers.lock().await.remove(&(id, remote));
+        match &mut res {
+            Ok(v) => {
+                if origin_id != id {
+                    v.set_id(origin_id);
+                }
+            }
+            Err(_) => {
+                self.handlers.lock().await.remove(&(id, remote));
+            }
         }
 
         res
@@ -205,9 +228,7 @@ impl MultiplexUdpClient {
 impl Client for UdpClient {
     async fn request(&self, req: &Message) -> Result<Message> {
         let w = requester().await?;
-        let res = w
-            .request(Clone::clone(req), self.addr, self.timeout)
-            .await?;
+        let res = w.request(req, self.addr, self.timeout).await?;
         Ok(res)
     }
 }
@@ -229,7 +250,6 @@ impl UdpClientBuilder {
 
 #[cfg(test)]
 mod tests {
-
     use crate::client::Client;
     use crate::protocol::{Class, Flags, Kind, Message, OpCode};
 

src/cmds/resolve.rs

@@ -100,7 +100,7 @@ fn print_resolve_result(
     req: &Message,
     res: &Message,
     begin: DateTime<Local>,
-) -> anyhow::Result<()> {
+) -> Result<()> {
     let cost = Local::now() - begin;
 
     println!();
@@ -114,7 +114,7 @@ fn print_resolve_result(
     println!(";; global options: +cmd");
     println!(";; Got answer:");
     println!(
-        ";; ->>HEADER<<- opcode: {:?}, status: {:?}, id: {}",
+        ";; ->>HEADER<<- opcode: {}, status: {}, id: {}",
         res.flags().opcode(),
         res.flags().response_code(),
         res.id()

src/protocol/frame.rs

@@ -52,6 +52,24 @@ pub enum RCode {
     NotZone = 10,
 }
 
+impl Display for RCode {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            RCode::NoError => "NOERROR",
+            RCode::FormatError => "FORMATERROR",
+            RCode::ServerFailure => "SERVERFAILURE",
+            RCode::NameError => "NAMEERROR",
+            RCode::NotImplemented => "NOTIMPLEMENTED",
+            RCode::Refused => "REFUSED",
+            RCode::YXDomain => "YXDOMAIN",
+            RCode::YXRRSet => "YXRRSET",
+            RCode::NXRRSet => "NXRRSET",
+            RCode::NotAuth => "NOTAUTH",
+            RCode::NotZone => "NOTZONE",
+        })
+    }
+}
+
 /// dns record types, see also https://en.wikipedia.org/wiki/List_of_DNS_record_types
 #[allow(clippy::upper_case_acronyms)]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, EnumIter, Hash)]