rumqttc: resume session only if CONNACK with session present 1 (byteb…

…eamio#864)

* Check if session present to restore pending publishes.

* Modify changelog.

* remove changes that don't seem to be related

* refactor: improve readability

* feat: apply changes to v4

* Remove session_expiry_interval related code.

* test: set clean session

* test: broker saved session

* test: fix resume reconnect

---------

Co-authored-by: Devdutt Shenoi <[email protected]>
Co-authored-by: Devdutt Shenoi <[email protected]>

rumqttc/CHANGELOG.md

@@ -28,6 +28,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Validate filters while creating subscription requests.
 * Make v4::Connect::write return correct value
+* Resume session only if broker sends `CONNACK` with `session_present == 1`.
 
 ### Security
 

rumqttc/src/eventloop.rs

@@ -172,6 +172,8 @@ impl EventLoop {
         match self.select().await {
             Ok(v) => Ok(v),
             Err(e) => {
+                // MQTT requires that packets pending acknowledgement should be republished on session resume.
+                // Move pending messages from state to eventloop.
                 self.clean();
                 Err(e)
             }

rumqttc/src/v5/eventloop.rs

@@ -163,6 +163,8 @@ impl EventLoop {
         match self.select().await {
             Ok(v) => Ok(v),
             Err(e) => {
+                // MQTT requires that packets pending acknowledgement should be republished on session resume.
+                // Move pending messages from state to eventloop.
                 self.clean();
                 Err(e)
             }
@@ -417,7 +419,6 @@ async fn mqtt_connect(
     // validate connack
     match network.read().await? {
         Incoming::ConnAck(connack) if connack.code == ConnectReturnCode::Success => {
-            // Override local keep_alive value if set by server.
             if let Some(props) = &connack.properties {
                 if let Some(keep_alive) = props.server_keep_alive {
                     options.keep_alive = Duration::from_secs(keep_alive as u64);

rumqttc/tests/broker.rs

@@ -21,7 +21,7 @@ pub struct Broker {
 
 impl Broker {
     /// Create a new broker which accepts 1 mqtt connection
-    pub async fn new(port: u16, connack: u8) -> Broker {
+    pub async fn new(port: u16, connack: u8, session_saved: bool) -> Broker {
         let addr = format!("127.0.0.1:{port}");
         let listener = TcpListener::bind(&addr).await.unwrap();
 
@@ -32,9 +32,12 @@ impl Broker {
         framed.readb(&mut incoming).await.unwrap();
 
         match incoming.pop_front().unwrap() {
-            Packet::Connect(_) => {
+            Packet::Connect(connect) => {
                 let connack = match connack {
-                    0 => ConnAck::new(ConnectReturnCode::Success, false),
+                    0 => ConnAck::new(
+                        ConnectReturnCode::Success,
+                        !connect.clean_session && session_saved,
+                    ),
                     1 => ConnAck::new(ConnectReturnCode::BadUserNamePassword, false),
                     _ => {
                         return Broker {

rumqttc/tests/reliability.rs

@@ -72,7 +72,7 @@ async fn _tick(
 #[tokio::test]
 async fn connection_should_timeout_on_time() {
     task::spawn(async move {
-        let _broker = Broker::new(1880, 3).await;
+        let _broker = Broker::new(1880, 3, false).await;
         time::sleep(Duration::from_secs(10)).await;
     });
 
@@ -125,7 +125,7 @@ async fn idle_connection_triggers_pings_on_time() {
         run(&mut eventloop, false).await.unwrap();
     });
 
-    let mut broker = Broker::new(1885, 0).await;
+    let mut broker = Broker::new(1885, 0, false).await;
     let mut count = 0;
     let mut start = Instant::now();
 
@@ -169,7 +169,7 @@ async fn some_outgoing_and_no_incoming_should_trigger_pings_on_time() {
         run(&mut eventloop, false).await.unwrap();
     });
 
-    let mut broker = Broker::new(1886, 0).await;
+    let mut broker = Broker::new(1886, 0, false).await;
     let mut count = 0;
     let mut start = Instant::now();
 
@@ -204,7 +204,7 @@ async fn some_incoming_and_no_outgoing_should_trigger_pings_on_time() {
         run(&mut eventloop, false).await.unwrap();
     });
 
-    let mut broker = Broker::new(2000, 0).await;
+    let mut broker = Broker::new(2000, 0, false).await;
     let mut count = 0;
 
     // Start sending qos 0 publishes to the client. This triggers
@@ -238,7 +238,7 @@ async fn detects_halfopen_connections_in_the_second_ping_request() {
 
     // A broker which consumes packets but doesn't reply
     task::spawn(async move {
-        let mut broker = Broker::new(2001, 0).await;
+        let mut broker = Broker::new(2001, 0, false).await;
         broker.blackhole().await;
     });
 
@@ -279,7 +279,7 @@ async fn requests_are_blocked_after_max_inflight_queue_size() {
         run(&mut eventloop, false).await.unwrap();
     });
 
-    let mut broker = Broker::new(1887, 0).await;
+    let mut broker = Broker::new(1887, 0, false).await;
     for i in 1..=10 {
         let packet = broker.read_publish().await;
 
@@ -306,7 +306,7 @@ async fn requests_are_recovered_after_inflight_queue_size_falls_below_max() {
         run(&mut eventloop, true).await.unwrap();
     });
 
-    let mut broker = Broker::new(1888, 0).await;
+    let mut broker = Broker::new(1888, 0, false).await;
 
     // packet 1, 2, and 3
     assert!(broker.read_publish().await.is_some());
@@ -341,7 +341,7 @@ async fn packet_id_collisions_are_detected_and_flow_control_is_applied() {
     });
 
     task::spawn(async move {
-        let mut broker = Broker::new(1891, 0).await;
+        let mut broker = Broker::new(1891, 0, false).await;
 
         // read all incoming packets first
         for i in 1..=4 {
@@ -449,8 +449,8 @@ async fn next_poll_after_connect_failure_reconnects() {
     let options = MqttOptions::new("dummy", "127.0.0.1", 3000);
 
     task::spawn(async move {
-        let _broker = Broker::new(3000, 1).await;
-        let _broker = Broker::new(3000, 0).await;
+        let _broker = Broker::new(3000, 1, false).await;
+        let _broker = Broker::new(3000, 0, false).await;
         time::sleep(Duration::from_secs(15)).await;
     });
 
@@ -474,7 +474,9 @@ async fn next_poll_after_connect_failure_reconnects() {
 #[tokio::test]
 async fn reconnection_resumes_from_the_previous_state() {
     let mut options = MqttOptions::new("dummy", "127.0.0.1", 3001);
-    options.set_keep_alive(Duration::from_secs(5));
+    options
+        .set_keep_alive(Duration::from_secs(5))
+        .set_clean_session(false);
 
     // start sending qos0 publishes. Makes sure that there is out activity but no in activity
     let (client, mut eventloop) = AsyncClient::new(options, 5);
@@ -489,7 +491,7 @@ async fn reconnection_resumes_from_the_previous_state() {
     });
 
     // broker connection 1
-    let mut broker = Broker::new(3001, 0).await;
+    let mut broker = Broker::new(3001, 0, false).await;
     for i in 1..=2 {
         let packet = broker.read_publish().await.unwrap();
         assert_eq!(i, packet.payload[0]);
@@ -503,7 +505,7 @@ async fn reconnection_resumes_from_the_previous_state() {
     // a block around broker with {} is closing the connection as expected
 
     // broker connection 2
-    let mut broker = Broker::new(3001, 0).await;
+    let mut broker = Broker::new(3001, 0, true).await;
     for i in 3..=4 {
         let packet = broker.read_publish().await.unwrap();
         assert_eq!(i, packet.payload[0]);
@@ -514,7 +516,9 @@ async fn reconnection_resumes_from_the_previous_state() {
 #[tokio::test]
 async fn reconnection_resends_unacked_packets_from_the_previous_connection_first() {
     let mut options = MqttOptions::new("dummy", "127.0.0.1", 3002);
-    options.set_keep_alive(Duration::from_secs(5));
+    options
+        .set_keep_alive(Duration::from_secs(5))
+        .set_clean_session(false);
 
     // start sending qos0 publishes. this makes sure that there is
     // outgoing activity but no incoming activity
@@ -530,14 +534,14 @@ async fn reconnection_resends_unacked_packets_from_the_previous_connection_first
     });
 
     // broker connection 1. receive but don't ack
-    let mut broker = Broker::new(3002, 0).await;
+    let mut broker = Broker::new(3002, 0, false).await;
     for i in 1..=2 {
         let packet = broker.read_publish().await.unwrap();
         assert_eq!(i, packet.payload[0]);
     }
 
     // broker connection 2 receives from scratch
-    let mut broker = Broker::new(3002, 0).await;
+    let mut broker = Broker::new(3002, 0, true).await;
     for i in 1..=6 {
         let packet = broker.read_publish().await.unwrap();
         assert_eq!(i, packet.payload[0]);
@@ -559,7 +563,7 @@ async fn state_is_being_cleaned_properly_and_pending_request_calculated_properly
     });
 
     task::spawn(async move {
-        let mut broker = Broker::new(3004, 0).await;
+        let mut broker = Broker::new(3004, 0, false).await;
         while (broker.read_packet().await).is_some() {
             time::sleep(Duration::from_secs_f64(0.5)).await;
         }