fixup local address detection

src/hp.rs

@@ -13,3 +13,23 @@ mod disco;
 mod hostinfo;
 pub mod key;
 mod netmap;
+
+use std::net::{IpAddr, Ipv6Addr};
+
+// TODO: replace with IpAddr::to_canoncial once stabilized.
+pub fn to_canonical(ip: IpAddr) -> IpAddr {
+    match ip {
+        ip @ IpAddr::V4(_) => ip,
+        IpAddr::V6(ip) => {
+            if let Some(ip) = ip.to_ipv4_mapped() {
+                IpAddr::V4(ip)
+            } else {
+                IpAddr::V6(ip)
+            }
+        }
+    }
+}
+// Copied from std lib, not stable yet
+pub const fn is_unicast_link_local(addr: Ipv6Addr) -> bool {
+    (addr.segments()[0] & 0xffc0) == 0xfe80
+}

src/hp/disco.rs

@@ -22,7 +22,7 @@ use std::{
 
 use anyhow::{anyhow, ensure, Result};
 
-use crate::hp::stun::to_canonical;
+use crate::hp::to_canonical;
 
 use super::{key, stun};