add signature to connection response packet

src/prudp/sockaddr.rs

@@ -1,8 +1,25 @@
+use std::io::Write;
 use std::net::SocketAddrV4;
+use hmac::{Hmac, Mac};
 use crate::prudp::packet::VirtualPort;
 
+type Md5Hmac = Hmac<md5::Md5>;
+
 #[derive(Eq, PartialEq, Hash, Debug, Copy, Clone)]
 pub struct PRUDPSockAddr{
     pub regular_socket_addr: SocketAddrV4,
     pub virtual_port: VirtualPort
+}
+
+impl PRUDPSockAddr{
+    pub fn calculate_connection_signature(&self) -> [u8; 16] {
+        let mut hmac = Md5Hmac::new_from_slice(&[0; 16]).expect("fuck");
+
+        let mut data = self.regular_socket_addr.ip().octets().to_vec();
+        data.extend_from_slice(&self.regular_socket_addr.port().to_be_bytes());
+
+        hmac.write_all(&data).expect("figuring this out was complete ass");
+        let result: [u8; 16] = hmac.finalize().into_bytes()[0..16].try_into().expect("fuck");
+        result
+    }
 }