1 files changed, 41 insertions, 0 deletions
diff --git a/p2p/src/routing_table/entry.rs b/p2p/src/routing_table/entry.rs
new file mode 100644
index 0000000..b3f219f
--- /dev/null
+++ b/p2p/src/routing_table/entry.rs
@@ -0,0 +1,41 @@
+use bincode::{Decode, Encode};
+
+use karyons_net::{Addr, Port};
+
+/// Specifies the size of the key, in bytes.
+pub const KEY_SIZE: usize = 32;
+
+/// An Entry represents a peer in the routing table.
+#[derive(Encode, Decode, Clone, Debug)]
+pub struct Entry {
+    /// The unique key identifying the peer.
+    pub key: Key,
+    /// The IP address of the peer.
+    pub addr: Addr,
+    /// TCP port
+    pub port: Port,
+    /// UDP/TCP port
+    pub discovery_port: Port,
+}
+
+impl PartialEq for Entry {
+    fn eq(&self, other: &Self) -> bool {
+        // XXX this should also compare both addresses (the self.addr == other.addr)
+        self.key == other.key
+    }
+}
+
+/// The unique key identifying the peer.
+pub type Key = [u8; KEY_SIZE];
+
+/// Calculates the XOR distance between two provided keys.
+///
+/// The XOR distance is a metric used in Kademlia to measure the closeness
+/// of keys.
+pub fn xor_distance(key: &Key, other: &Key) -> Key {
+    let mut res = [0; 32];
+    for (i, (k, o)) in key.iter().zip(other.iter()).enumerate() {
+        res[i] = k ^ o;
+    }
+    res
+}