Function detect_interface_gateways

src/apps/desktop/src/api/remote_connect_api.rs:307–390

Detect per-interface gateway IPs by parsing the system routing table. Returns a map keyed by interface identifier (interface name on macOS/Linux, interface IP on Windows) → gateway IP. Only interfaces that have a default route entry appear in the map.

()

/// interface IP on Windows) → gateway IP.  Only interfaces that have a default
/// route entry appear in the map.
fn detect_interface_gateways() -> HashMap<String, String> {
    let mut map = HashMap::new();

    #[cfg(target_os = "macos")]
    {
        if let Ok(output) = bitfun_core::util::process_manager::create_command("netstat")
            .args(["-rn", "-f", "inet"])
            .output()
        {
            if output.status.success() {
                let stdout = String::from_utf8_lossy(&output.stdout);
                // Lines look like:
                //   default            192.168.1.1       UGScg    en0
                for line in stdout.lines() {
                    let parts: Vec<&str> = line.split_whitespace().collect();
                    if parts.len() >= 4 && parts[0] == "default" {
                        let gateway = parts[1];
                        let netif = parts[3];
                        if is_ipv4(gateway) {
                            map.insert(netif.to_string(), gateway.to_string());
                        }
                    }
                }
            }
        }
    }

    #[cfg(target_os = "linux")]
    {
        if let Ok(output) = bitfun_core::util::process_manager::create_command("ip")
            .args(["route", "show", "default"])
            .output()
        {
            if output.status.success() {
                let stdout = String::from_utf8_lossy(&output.stdout);
                // Lines look like:
                //   default via 192.168.1.1 dev eth0 proto dhcp metric 100
                for line in stdout.lines() {
                    let parts: Vec<&str> = line.split_whitespace().collect();
                    let mut via = None;
                    let mut dev = None;
                    for i in 0..parts.len() {
                        match parts[i] {
                            "via" if i + 1 < parts.len() => via = Some(parts[i + 1]),
                            "dev" if i + 1 < parts.len() => dev = Some(parts[i + 1]),
                            _ => {}
                        }
                    }
                    if let (Some(gw), Some(iface)) = (via, dev) {
                        if is_ipv4(gw) {
                            map.insert(iface.to_string(), gw.to_string());
                        }
                    }
                }
            }
        }
    }