Work on Linux platform code

src/wireguard/handshake/timestamp.rs

@@ -0,0 +1,32 @@
+use std::time::{SystemTime, UNIX_EPOCH};
+
+pub type TAI64N = [u8; 12];
+
+const TAI64_EPOCH: u64 = 0x400000000000000a;
+
+pub const ZERO: TAI64N = [0u8; 12];
+
+pub fn now() -> TAI64N {
+    // get system time as duration
+    let sysnow = SystemTime::now();
+    let delta = sysnow.duration_since(UNIX_EPOCH).unwrap();
+
+    // convert to tai64n
+    let tai64_secs = delta.as_secs() + TAI64_EPOCH;
+    let tai64_nano = delta.subsec_nanos();
+
+    // serialize
+    let mut res = [0u8; 12];
+    res[..8].copy_from_slice(&tai64_secs.to_be_bytes()[..]);
+    res[8..].copy_from_slice(&tai64_nano.to_be_bytes()[..]);
+    res
+}
+
+pub fn compare(old: &TAI64N, new: &TAI64N) -> bool {
+    for i in 0..12 {
+        if new[i] > old[i] {
+            return true;
+        }
+    }
+    return false;
+}