cmcconnell1 · October 10, 2024 01:02 · Oct 10, 2024
diff --git a/main.rs b/main.rs
@@ -0,0 +1,62 @@
+use std::net::{SocketAddr, IpAddr, Ipv4Addr};
+
+/// Checks if a given `SocketAddr` is within the specified local IP ranges:
+/// - 127.0.0.1 (loopback address)
+/// - 10.0.0.0/8
+/// - 172.16.0.0/12
+/// - 192.168.0.0/16
+fn is_local(addr: &SocketAddr) -> bool {
+    match addr.ip() {
+        IpAddr::V4(ip) => {
+            // Check if the IP is 127.0.0.1 (loopback address)
+            ip == Ipv4Addr::LOCALHOST
+            // Check if the IP is within the 10.0.0.0/8 range
+            || (ip.octets()[0] == 10)
+            // Check if the IP is within the 172.16.0.0/12 range (172.16.0.0 to 172.31.255.255)
+            || (ip.octets()[0] == 172 && (16..=31).contains(&ip.octets()[1]))
+            // Check if the IP is within the 192.168.0.0/16 range
+            || (ip.octets()[0] == 192 && ip.octets()[1] == 168)
+        }
+        // Only IPv4 addresses are considered; IPv6 addresses are not local by these criteria.
+        IpAddr::V6(_) => false,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::net::{SocketAddr, Ipv4Addr};
+
+    #[test]
+    fn test_is_local() {
+        // Test cases for IPs that should be considered local
+        let local_ips = [
+            "127.0.0.1:8080",    // Loopback address
+            "10.0.0.1:8080",     // Within 10.0.0.0/8 range
+            "172.16.0.1:8080",   // Within 172.16.0.0/12 range
+            "192.168.0.1:8080",  // Within 192.168.0.0/16 range
+        ];
+
+        for ip_str in &local_ips {
+            // Parse the string into a `SocketAddr` type
+            let addr: SocketAddr = ip_str.parse().expect("Failed to parse IP");
+            // Assert that the IP is recognized as local
+            assert!(is_local(&addr), "Expected {} to be local", ip_str);
+        }
+
+        // Test cases for IPs that should be considered non-local
+        let non_local_ips = [
+            "8.8.8.8:8080",       // Google DNS, non-local
+            "172.32.0.1:8080",    // Outside 172.16.0.0/12 range
+            "192.169.0.1:8080",   // Outside 192.168.0.0/16 range
+            "11.0.0.1:8080",      // Outside 10.0.0.0/8 range
+        ];
+
+        for ip_str in &non_local_ips {
+            // Parse the string into a `SocketAddr` type
+            let addr: SocketAddr = ip_str.parse().expect("Failed to parse IP");
+            // Assert that the IP is not recognized as local
+            assert!(!is_local(&addr), "Expected {} to be non-local", ip_str);
+        }
+    }
+}