Inherited per-user unique IP limit

src/api/runtime_zero.rs

@@ -90,6 +90,7 @@ pub(super) struct EffectiveMiddleProxyLimits {
 
 #[derive(Serialize)]
 pub(super) struct EffectiveUserIpPolicyLimits {
+    pub(super) global_each: usize,
     pub(super) mode: &'static str,
     pub(super) window_secs: u64,
 }
@@ -262,6 +263,7 @@ pub(super) fn build_limits_effective_data(cfg: &ProxyConfig) -> EffectiveLimitsD
             me2dc_fallback: cfg.general.me2dc_fallback,
         },
         user_ip_policy: EffectiveUserIpPolicyLimits {
+            global_each: cfg.access.user_max_unique_ips_global_each,
             mode: user_max_unique_ips_mode_label(cfg.access.user_max_unique_ips_mode),
             window_secs: cfg.access.user_max_unique_ips_window_secs,
         },

src/api/users.rs

@@ -386,7 +386,16 @@ pub(super) async fn users_from_config(
                 .get(&username)
                 .map(chrono::DateTime::<chrono::Utc>::to_rfc3339),
             data_quota_bytes: cfg.access.user_data_quota.get(&username).copied(),
-            max_unique_ips: cfg.access.user_max_unique_ips.get(&username).copied(),
+            max_unique_ips: cfg
+                .access
+                .user_max_unique_ips
+                .get(&username)
+                .copied()
+                .filter(|limit| *limit > 0)
+                .or(
+                    (cfg.access.user_max_unique_ips_global_each > 0)
+                        .then_some(cfg.access.user_max_unique_ips_global_each),
+                ),
             current_connections: stats.get_user_curr_connects(&username),
             active_unique_ips: active_ip_list.len(),
             active_unique_ips_list: active_ip_list,

src/config/defaults.rs

@@ -639,6 +639,10 @@ pub(crate) fn default_user_max_unique_ips_window_secs() -> u64 {
     DEFAULT_USER_MAX_UNIQUE_IPS_WINDOW_SECS
 }
 
+pub(crate) fn default_user_max_unique_ips_global_each() -> usize {
+    0
+}
+
 // Custom deserializer helpers
 
 #[derive(Deserialize)]

src/config/hot_reload.rs

@@ -119,6 +119,7 @@ pub struct HotFields {
     pub user_expirations:        std::collections::HashMap<String, chrono::DateTime<chrono::Utc>>,
     pub user_data_quota:         std::collections::HashMap<String, u64>,
     pub user_max_unique_ips:     std::collections::HashMap<String, usize>,
+    pub user_max_unique_ips_global_each: usize,
     pub user_max_unique_ips_mode: crate::config::UserMaxUniqueIpsMode,
     pub user_max_unique_ips_window_secs: u64,
 }
@@ -234,6 +235,7 @@ impl HotFields {
             user_expirations:        cfg.access.user_expirations.clone(),
             user_data_quota:         cfg.access.user_data_quota.clone(),
             user_max_unique_ips:     cfg.access.user_max_unique_ips.clone(),
+            user_max_unique_ips_global_each: cfg.access.user_max_unique_ips_global_each,
             user_max_unique_ips_mode: cfg.access.user_max_unique_ips_mode,
             user_max_unique_ips_window_secs: cfg.access.user_max_unique_ips_window_secs,
         }
@@ -535,6 +537,7 @@ fn overlay_hot_fields(old: &ProxyConfig, new: &ProxyConfig) -> ProxyConfig {
     cfg.access.user_expirations = new.access.user_expirations.clone();
     cfg.access.user_data_quota = new.access.user_data_quota.clone();
     cfg.access.user_max_unique_ips = new.access.user_max_unique_ips.clone();
+    cfg.access.user_max_unique_ips_global_each = new.access.user_max_unique_ips_global_each;
     cfg.access.user_max_unique_ips_mode = new.access.user_max_unique_ips_mode;
     cfg.access.user_max_unique_ips_window_secs = new.access.user_max_unique_ips_window_secs;
 
@@ -1109,12 +1112,14 @@ fn log_changes(
             new_hot.user_max_unique_ips.len()
         );
     }
-    if old_hot.user_max_unique_ips_mode != new_hot.user_max_unique_ips_mode
+    if old_hot.user_max_unique_ips_global_each != new_hot.user_max_unique_ips_global_each
+        || old_hot.user_max_unique_ips_mode != new_hot.user_max_unique_ips_mode
         || old_hot.user_max_unique_ips_window_secs
             != new_hot.user_max_unique_ips_window_secs
     {
         info!(
-            "config reload: user_max_unique_ips policy mode={:?} window={}s",
+            "config reload: user_max_unique_ips policy global_each={} mode={:?} window={}s",
+            new_hot.user_max_unique_ips_global_each,
             new_hot.user_max_unique_ips_mode,
             new_hot.user_max_unique_ips_window_secs
         );

src/config/types.rs

@@ -1323,6 +1323,11 @@ pub struct AccessConfig {
     #[serde(default)]
     pub user_max_unique_ips: HashMap<String, usize>,
 
+    /// Global per-user unique IP limit applied when a user has no individual override.
+    /// `0` disables the inherited limit.
+    #[serde(default = "default_user_max_unique_ips_global_each")]
+    pub user_max_unique_ips_global_each: usize,
+
     #[serde(default)]
     pub user_max_unique_ips_mode: UserMaxUniqueIpsMode,
 
@@ -1348,6 +1353,7 @@ impl Default for AccessConfig {
             user_expirations: HashMap::new(),
             user_data_quota: HashMap::new(),
             user_max_unique_ips: HashMap::new(),
+            user_max_unique_ips_global_each: default_user_max_unique_ips_global_each(),
             user_max_unique_ips_mode: UserMaxUniqueIpsMode::default(),
             user_max_unique_ips_window_secs: default_user_max_unique_ips_window_secs(),
             replay_check_len: default_replay_check_len(),

src/ip_tracker.rs

@@ -17,6 +17,7 @@ pub struct UserIpTracker {
     active_ips: Arc<RwLock<HashMap<String, HashMap<IpAddr, usize>>>>,
     recent_ips: Arc<RwLock<HashMap<String, HashMap<IpAddr, Instant>>>>,
     max_ips: Arc<RwLock<HashMap<String, usize>>>,
+    default_max_ips: Arc<RwLock<usize>>,
     limit_mode: Arc<RwLock<UserMaxUniqueIpsMode>>,
     limit_window: Arc<RwLock<Duration>>,
     last_compact_epoch_secs: Arc<AtomicU64>,
@@ -28,6 +29,7 @@ impl UserIpTracker {
             active_ips: Arc::new(RwLock::new(HashMap::new())),
             recent_ips: Arc::new(RwLock::new(HashMap::new())),
             max_ips: Arc::new(RwLock::new(HashMap::new())),
+            default_max_ips: Arc::new(RwLock::new(0)),
             limit_mode: Arc::new(RwLock::new(UserMaxUniqueIpsMode::ActiveWindow)),
             limit_window: Arc::new(RwLock::new(Duration::from_secs(30))),
             last_compact_epoch_secs: Arc::new(AtomicU64::new(0)),
@@ -100,7 +102,10 @@ impl UserIpTracker {
         limits.remove(username);
     }
 
-    pub async fn load_limits(&self, limits: &HashMap<String, usize>) {
+    pub async fn load_limits(&self, default_limit: usize, limits: &HashMap<String, usize>) {
+        let mut default_max_ips = self.default_max_ips.write().await;
+        *default_max_ips = default_limit;
+        drop(default_max_ips);
         let mut max_ips = self.max_ips.write().await;
         max_ips.clone_from(limits);
     }
@@ -114,9 +119,14 @@ impl UserIpTracker {
 
     pub async fn check_and_add(&self, username: &str, ip: IpAddr) -> Result<(), String> {
         self.maybe_compact_empty_users().await;
+        let default_max_ips = *self.default_max_ips.read().await;
         let limit = {
             let max_ips = self.max_ips.read().await;
-            max_ips.get(username).copied()
+            max_ips
+                .get(username)
+                .copied()
+                .filter(|limit| *limit > 0)
+                .or((default_max_ips > 0).then_some(default_max_ips))
         };
         let mode = *self.limit_mode.read().await;
         let window = *self.limit_window.read().await;
@@ -255,10 +265,16 @@ impl UserIpTracker {
     pub async fn get_stats(&self) -> Vec<(String, usize, usize)> {
         let active_ips = self.active_ips.read().await;
         let max_ips = self.max_ips.read().await;
+        let default_max_ips = *self.default_max_ips.read().await;
 
         let mut stats = Vec::new();
         for (username, user_ips) in active_ips.iter() {
-            let limit = max_ips.get(username).copied().unwrap_or(0);
+            let limit = max_ips
+                .get(username)
+                .copied()
+                .filter(|limit| *limit > 0)
+                .or((default_max_ips > 0).then_some(default_max_ips))
+                .unwrap_or(0);
             stats.push((username.clone(), user_ips.len(), limit));
         }
 
@@ -293,8 +309,13 @@ impl UserIpTracker {
     }
 
     pub async fn get_user_limit(&self, username: &str) -> Option<usize> {
+        let default_max_ips = *self.default_max_ips.read().await;
         let max_ips = self.max_ips.read().await;
-        max_ips.get(username).copied()
+        max_ips
+            .get(username)
+            .copied()
+            .filter(|limit| *limit > 0)
+            .or((default_max_ips > 0).then_some(default_max_ips))
     }
 
     pub async fn format_stats(&self) -> String {
@@ -546,7 +567,7 @@ mod tests {
         config_limits.insert("user1".to_string(), 5);
         config_limits.insert("user2".to_string(), 3);
 
-        tracker.load_limits(&config_limits).await;
+        tracker.load_limits(0, &config_limits).await;
 
         assert_eq!(tracker.get_user_limit("user1").await, Some(5));
         assert_eq!(tracker.get_user_limit("user2").await, Some(3));
@@ -560,16 +581,46 @@ mod tests {
         let mut first = HashMap::new();
         first.insert("user1".to_string(), 2);
         first.insert("user2".to_string(), 3);
-        tracker.load_limits(&first).await;
+        tracker.load_limits(0, &first).await;
 
         let mut second = HashMap::new();
         second.insert("user2".to_string(), 5);
-        tracker.load_limits(&second).await;
+        tracker.load_limits(0, &second).await;
 
         assert_eq!(tracker.get_user_limit("user1").await, None);
         assert_eq!(tracker.get_user_limit("user2").await, Some(5));
     }
 
+    #[tokio::test]
+    async fn test_global_each_limit_applies_without_user_override() {
+        let tracker = UserIpTracker::new();
+        tracker.load_limits(2, &HashMap::new()).await;
+
+        let ip1 = test_ipv4(172, 16, 0, 1);
+        let ip2 = test_ipv4(172, 16, 0, 2);
+        let ip3 = test_ipv4(172, 16, 0, 3);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip2).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip3).await.is_err());
+        assert_eq!(tracker.get_user_limit("test_user").await, Some(2));
+    }
+
+    #[tokio::test]
+    async fn test_user_override_wins_over_global_each_limit() {
+        let tracker = UserIpTracker::new();
+        let mut limits = HashMap::new();
+        limits.insert("test_user".to_string(), 1);
+        tracker.load_limits(3, &limits).await;
+
+        let ip1 = test_ipv4(172, 17, 0, 1);
+        let ip2 = test_ipv4(172, 17, 0, 2);
+
+        assert!(tracker.check_and_add("test_user", ip1).await.is_ok());
+        assert!(tracker.check_and_add("test_user", ip2).await.is_err());
+        assert_eq!(tracker.get_user_limit("test_user").await, Some(1));
+    }
+
     #[tokio::test]
     async fn test_time_window_mode_blocks_recent_ip_churn() {
         let tracker = UserIpTracker::new();

src/maestro/mod.rs

@@ -168,17 +168,24 @@ pub async fn run() -> std::result::Result<(), Box<dyn std::error::Error>> {
         stats.clone(),
     ));
     let ip_tracker = Arc::new(UserIpTracker::new());
-    ip_tracker.load_limits(&config.access.user_max_unique_ips).await;
+    ip_tracker
+        .load_limits(
+            config.access.user_max_unique_ips_global_each,
+            &config.access.user_max_unique_ips,
+        )
+        .await;
     ip_tracker
         .set_limit_policy(
             config.access.user_max_unique_ips_mode,
             config.access.user_max_unique_ips_window_secs,
         )
         .await;
-    if !config.access.user_max_unique_ips.is_empty() {
+    if config.access.user_max_unique_ips_global_each > 0 || !config.access.user_max_unique_ips.is_empty()
+    {
         info!(
-            "IP limits configured for {} users",
-            config.access.user_max_unique_ips.len()
+            global_each_limit = config.access.user_max_unique_ips_global_each,
+            explicit_user_limits = config.access.user_max_unique_ips.len(),
+            "User unique IP limits configured"
         );
     }
     if !config.network.dns_overrides.is_empty() {

src/maestro/runtime_tasks.rs

@@ -131,6 +131,10 @@ pub(crate) async fn spawn_runtime_tasks(
     let mut config_rx_ip_limits = config_rx.clone();
     tokio::spawn(async move {
         let mut prev_limits = config_rx_ip_limits.borrow().access.user_max_unique_ips.clone();
+        let mut prev_global_each = config_rx_ip_limits
+            .borrow()
+            .access
+            .user_max_unique_ips_global_each;
         let mut prev_mode = config_rx_ip_limits.borrow().access.user_max_unique_ips_mode;
         let mut prev_window = config_rx_ip_limits
             .borrow()
@@ -143,9 +147,17 @@ pub(crate) async fn spawn_runtime_tasks(
             }
             let cfg = config_rx_ip_limits.borrow_and_update().clone();
 
-            if prev_limits != cfg.access.user_max_unique_ips {
-                ip_tracker_policy.load_limits(&cfg.access.user_max_unique_ips).await;
+            if prev_limits != cfg.access.user_max_unique_ips
+                || prev_global_each != cfg.access.user_max_unique_ips_global_each
+            {
+                ip_tracker_policy
+                    .load_limits(
+                        cfg.access.user_max_unique_ips_global_each,
+                        &cfg.access.user_max_unique_ips,
+                    )
+                    .await;
                 prev_limits = cfg.access.user_max_unique_ips.clone();
+                prev_global_each = cfg.access.user_max_unique_ips_global_each;
             }
 
             if prev_mode != cfg.access.user_max_unique_ips_mode

src/metrics.rs

@@ -1774,14 +1774,24 @@ async fn render_metrics(stats: &Stats, config: &ProxyConfig, ip_tracker: &UserIp
             "# HELP telemt_user_unique_ips_recent_window Per-user unique IPs seen in configured observation window"
         );
         let _ = writeln!(out, "# TYPE telemt_user_unique_ips_recent_window gauge");
-        let _ = writeln!(out, "# HELP telemt_user_unique_ips_limit Per-user configured unique IP limit (0 means unlimited)");
+        let _ = writeln!(out, "# HELP telemt_user_unique_ips_limit Effective per-user unique IP limit (0 means unlimited)");
         let _ = writeln!(out, "# TYPE telemt_user_unique_ips_limit gauge");
         let _ = writeln!(out, "# HELP telemt_user_unique_ips_utilization Per-user unique IP usage ratio (0 for unlimited)");
         let _ = writeln!(out, "# TYPE telemt_user_unique_ips_utilization gauge");
 
         for user in unique_users {
             let current = ip_counts.get(&user).copied().unwrap_or(0);
-            let limit = config.access.user_max_unique_ips.get(&user).copied().unwrap_or(0);
+            let limit = config
+                .access
+                .user_max_unique_ips
+                .get(&user)
+                .copied()
+                .filter(|limit| *limit > 0)
+                .or(
+                    (config.access.user_max_unique_ips_global_each > 0)
+                        .then_some(config.access.user_max_unique_ips_global_each),
+                )
+                .unwrap_or(0);
             let utilization = if limit > 0 {
                 current as f64 / limit as f64
             } else {
@@ -1904,6 +1914,25 @@ mod tests {
         assert!(output.contains("telemt_user_unique_ips_recent_window{user="));
     }
 
+    #[tokio::test]
+    async fn test_render_uses_global_each_unique_ip_limit() {
+        let stats = Stats::new();
+        stats.increment_user_connects("alice");
+        stats.increment_user_curr_connects("alice");
+        let tracker = UserIpTracker::new();
+        tracker
+            .check_and_add("alice", "203.0.113.10".parse().unwrap())
+            .await
+            .unwrap();
+        let mut config = ProxyConfig::default();
+        config.access.user_max_unique_ips_global_each = 2;
+
+        let output = render_metrics(&stats, &config, &tracker).await;
+
+        assert!(output.contains("telemt_user_unique_ips_limit{user=\"alice\"} 2"));
+        assert!(output.contains("telemt_user_unique_ips_utilization{user=\"alice\"} 0.500000"));
+    }
+
     #[tokio::test]
     async fn test_render_has_type_annotations() {
         let stats = Stats::new();