rust local IP test

main.rs

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);
        }
    }
}