add feature flag to allow duplicate clientid (#580)

bytebeamio · Feb 14, 2023 · 3c611f6 · 3c611f6
1 parent d6f1063
commit 3c611f6
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Showing 3 changed files with 18 additions and 12 deletions.
diff --git a/rumqttd/Cargo.toml b/rumqttd/Cargo.toml
@@ -40,6 +40,7 @@ use-rustls = ["dep:tokio-rustls", "dep:rustls-pemfile", "dep:x509-parser"]
 use-native-tls = ["dep:tokio-native-tls", "dep:x509-parser"]
 websockets = ["dep:tokio-tungstenite", "dep:websocket-codec", "dep:tokio-util", "dep:futures-util"]
 validate-tenant-prefix = []
+allow-duplicate-clientid = []
 
 [dev-dependencies]
 pretty_env_logger = "0.4.0"

diff --git a/rumqttd/src/link/remote.rs b/rumqttd/src/link/remote.rs
@@ -107,8 +107,11 @@ impl<P: Protocol> RemoteLink<P> {
         let client_id = connect.client_id.clone();
         let clean_session = connect.clean_session;
 
-        // Don't allow empty client_id
-        if client_id.is_empty() {
+        if cfg!(feature = "allow-duplicate-clientid") {
+            if !clean_session && client_id.is_empty() {
+                return Err(Error::InvalidClientId);
+            }
+        } else if client_id.is_empty() {
             return Err(Error::InvalidClientId);
         }
 

diff --git a/rumqttd/src/router/routing.rs b/rumqttd/src/router/routing.rs
@@ -261,16 +261,18 @@ impl Router {
         let span = tracing::info_span!("incoming_connect", client_id);
         let _guard = span.enter();
 
-        // Check if same client_id already exists and if so, replace it with this new connection
-        // ref: https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718032
-
-        let connection_id = self.connection_map.get(&client_id);
-        if let Some(connection_id) = connection_id {
-            error!(
-                "Duplicate client_id, dropping previous connection with connection_id: {}",
-                connection_id
-            );
-            self.handle_disconnection(*connection_id, true);
+        if cfg!(not(feature = "allow-duplicate-clientid")) {
+            // Check if same client_id already exists and if so, replace it with this new connection
+            // ref: https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718032
+
+            let connection_id = self.connection_map.get(&client_id);
+            if let Some(connection_id) = connection_id {
+                error!(
+                    "Duplicate client_id, dropping previous connection with connection_id: {}",
+                    connection_id
+                );
+                self.handle_disconnection(*connection_id, true);
+            }
         }
 
         if self.connections.len() >= self.config.max_connections {