2 files changed, 80 insertions, 0 deletions
diff --git a/src-tauri/src/platform_specific/mod.rs b/src-tauri/src/platform_specific/mod.rs
index 6fdb1ed1..4e0514d4 100644
--- a/src-tauri/src/platform_specific/mod.rs
+++ b/src-tauri/src/platform_specific/mod.rs
@@ -38,3 +38,13 @@ pub async fn get_local_northstar_proton_wrapper_version() -> Result<String, Stri
     #[cfg(target_os = "windows")]
     Err("Not supported on Windows".to_string())
 }
+
+/// Check whether the current device might be behind a CGNAT
+#[tauri::command]
+pub async fn check_cgnat() -> Result<String, String> {
+    #[cfg(target_os = "linux")]
+    return Err("Not supported on Linux".to_string());
+
+    #[cfg(target_os = "windows")]
+    windows::check_cgnat().await
+}
diff --git a/src-tauri/src/platform_specific/windows.rs b/src-tauri/src/platform_specific/windows.rs
index 678e5be5..fc6aab5d 100644
--- a/src-tauri/src/platform_specific/windows.rs
+++ b/src-tauri/src/platform_specific/windows.rs
@@ -1,5 +1,6 @@
 /// Windows specific code
 use anyhow::{anyhow, Result};
+use std::net::Ipv4Addr;
 
 #[cfg(target_os = "windows")]
 use winreg::{enums::HKEY_LOCAL_MACHINE, RegKey};
@@ -32,3 +33,72 @@ pub fn origin_install_location_detection() -> Result<String, anyhow::Error> {
 
     Err(anyhow!("No Origin / EA App install path found"))
 }
+
+/// Check whether the current device might be behind a CGNAT
+pub async fn check_cgnat() -> Result<String, String> {
+    // Use external service to grap IP
+    let url = "https://api.ipify.org";
+    let response = reqwest::get(url).await.unwrap().text().await.unwrap();
+
+    // Check if valid IPv4 address and return early if not
+    if response.parse::<Ipv4Addr>().is_err() {
+        return Err(format!("Not valid IPv4 address: {}", response));
+    }
+
+    let hops_count = run_tracert(&response)?;
+    Ok(format!("Counted {} hops to {}", hops_count, response))
+}
+
+/// Count number of hops in tracert output
+fn count_hops(output: &str) -> usize {
+    // Split the output into lines
+    let lines: Vec<&str> = output.lines().collect();
+
+    // Filter lines that appear to represent hops
+    let hop_lines: Vec<&str> = lines
+        .iter()
+        .filter(|&line| line.contains("ms") || line.contains("*")) // TODO check if it contains just the `ms` surrounded by whitespace, otherwise it might falsely pick up some domain names as well
+        .cloned()
+        .collect();
+
+    // Return the number of hops
+    hop_lines.len()
+}
+
+/// Run `tracert`
+fn run_tracert(target_ip: &str) -> Result<usize, String> {
+    // Ensure valid IPv4 address to avoid prevent command injection
+    assert!(target_ip.parse::<Ipv4Addr>().is_ok());
+
+    // Execute the `tracert` command
+    let output = match std::process::Command::new("tracert")
+        .arg("-4") // Force IPv4
+        .arg("-d") // Prevent resolving intermediate IP addresses
+        .arg("-w") // Set timeout to 1 second
+        .arg("1000")
+        .arg("-h") // Set max hop count
+        .arg("5")
+        .arg(target_ip)
+        .output()
+    {
+        Ok(res) => res,
+        Err(err) => return Err(format!("Failed running tracert: {}", err)),
+    };
+
+    // Check if the command was successful
+    if output.status.success() {
+        // Convert the output to a string
+        let stdout =
+            std::str::from_utf8(&output.stdout).expect("Invalid UTF-8 sequence in command output");
+        println!("{}", stdout);
+
+        // Count the number of hops
+        let hop_count = count_hops(stdout);
+        Ok(hop_count)
+    } else {
+        let stderr = std::str::from_utf8(&output.stderr)
+            .expect("Invalid UTF-8 sequence in command error output");
+        println!("{}", stderr);
+        Err(format!("Failed collecting tracert output: {}", stderr))
+    }
+}