fix(otg): 适配 OpenWrt netifd 网络桥接与事务恢复

src/otg/network_backend.rs

@@ -0,0 +1,74 @@
+//! Select OpenWrt netifd or a running NetworkManager, with an explicit override.
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum NetworkBackend {
+    NetworkManager,
+    Netifd,
+}
+
+pub(crate) fn select_backend(
+    requested: Option<&str>,
+    openwrt_release_present: bool,
+) -> Result<NetworkBackend, String> {
+    match requested.unwrap_or("auto") {
+        "auto" if openwrt_release_present => Ok(NetworkBackend::Netifd),
+        "auto" | "networkmanager" => Ok(NetworkBackend::NetworkManager),
+        "netifd" => Ok(NetworkBackend::Netifd),
+        value => Err(format!(
+            "Unknown ONE_KVM_NETWORK_BACKEND={value}; expected auto, networkmanager or netifd"
+        )),
+    }
+}
+
+pub(crate) fn current_backend() -> Result<NetworkBackend, String> {
+    let requested = std::env::var("ONE_KVM_NETWORK_BACKEND").ok();
+    let backend = select_backend(
+        requested.as_deref(),
+        std::path::Path::new("/etc/openwrt_release").is_file(),
+    )?;
+    if backend == NetworkBackend::NetworkManager {
+        let status = std::process::Command::new("nmcli")
+            .env("LC_ALL", "C")
+            .args(["-t", "-f", "RUNNING", "general"])
+            .output()
+            .map_err(|_| {
+                "OTG bridging requires NetworkManager and nmcli on this system".to_string()
+            })?;
+        if !status.status.success() || String::from_utf8_lossy(&status.stdout).trim() != "running" {
+            return Err("NetworkManager is not running; OTG bridging cannot manage this system's interfaces".to_string());
+        }
+    }
+    Ok(backend)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn automatic_selection_respects_openwrt_marker() {
+        assert_eq!(select_backend(None, true), Ok(NetworkBackend::Netifd));
+        assert_eq!(
+            select_backend(Some("auto"), false),
+            Ok(NetworkBackend::NetworkManager)
+        );
+    }
+
+    #[test]
+    fn explicit_selection_is_respected() {
+        assert_eq!(
+            select_backend(Some("networkmanager"), true),
+            Ok(NetworkBackend::NetworkManager)
+        );
+        assert_eq!(
+            select_backend(Some("netifd"), false),
+            Ok(NetworkBackend::Netifd)
+        );
+    }
+
+    #[test]
+    fn unknown_selection_is_not_silently_ignored() {
+        assert!(select_backend(Some("typo"), true).is_err());
+        assert!(select_backend(Some(""), false).is_err());
+    }
+}