Decouple sysctl runtime validation and modprobe dependencies

traffic_core/src/config.rs

@@ -287,6 +287,25 @@ impl Config {
         self.check_host_tools()
     }
 
+    pub fn validate_sysctl_tuning_runtime(&self) -> anyhow::Result<()> {
+        self.validate_config()?;
+
+        if !self.sysctl_tuning.enabled {
+            return Ok(());
+        }
+
+        if !tool_exists("sysctl") {
+            anyhow::bail!("required host tool not found in PATH: sysctl");
+        }
+
+        let tcp_bbr_mode = self.sysctl_tuning.tcp_bbr.trim().to_ascii_lowercase();
+        if tcp_bbr_mode == "require" && !tool_exists("modprobe") {
+            anyhow::bail!("required host tool not found in PATH: modprobe");
+        }
+
+        Ok(())
+    }
+
     pub fn validate_all(&self) -> anyhow::Result<()> {
         self.validate_config()?;
         self.validate_runtime()?;
@@ -299,12 +318,15 @@ impl Config {
             anyhow::bail!("required host tool not found in PATH: nsenter");
         }
         required.push("nsenter");
+        let tcp_bbr_mode = self.sysctl_tuning.tcp_bbr.trim().to_ascii_lowercase();
         if self.sysctl_tuning.enabled {
             required.push("sysctl");
         }
-        if self.sysctl_tuning.enabled
-            && self.sysctl_tuning.tcp_bbr.trim().to_ascii_lowercase() == "require"
-        {
+        if requires_modprobe(
+            self.traffic.enabled,
+            self.sysctl_tuning.enabled,
+            &tcp_bbr_mode,
+        ) {
             required.push("modprobe");
         }
         if self.anti_torrent.enabled {
@@ -328,6 +350,9 @@ impl Config {
             ]);
         }
 
+        required.sort_unstable();
+        required.dedup();
+
         for tool in required {
             if !tool_exists(tool) {
                 anyhow::bail!("required host tool not found in PATH: {tool}");
@@ -383,6 +408,10 @@ impl Config {
     }
 }
 
+fn requires_modprobe(traffic_enabled: bool, sysctl_enabled: bool, tcp_bbr_mode: &str) -> bool {
+    traffic_enabled || (sysctl_enabled && tcp_bbr_mode == "require")
+}
+
 fn parse_hhmm(v: &str) -> anyhow::Result<()> {
     let mut s = v.split(':');
     let h = s
@@ -707,4 +736,25 @@ swappiness = 1
         assert!(cfg.sysctl_tuning.apply_on_daemon_start);
         assert_eq!(cfg.sysctl_tuning.tcp_bbr, "auto");
     }
+
+    #[test]
+    fn validate_sysctl_tuning_runtime_skips_modprobe_for_auto_when_disabled() {
+        let mut cfg = base_config();
+        cfg.sysctl_tuning.enabled = false;
+        cfg.sysctl_tuning.tcp_bbr = "auto".into();
+        assert!(cfg.validate_sysctl_tuning_runtime().is_ok());
+    }
+
+    #[test]
+    fn requires_modprobe_when_traffic_enabled() {
+        assert!(requires_modprobe(true, true, "auto"));
+        assert!(requires_modprobe(true, false, "off"));
+    }
+
+    #[test]
+    fn requires_modprobe_for_sysctl_require_mode() {
+        assert!(requires_modprobe(false, true, "require"));
+        assert!(!requires_modprobe(false, true, "auto"));
+        assert!(!requires_modprobe(false, true, "off"));
+    }
 }