tor-cell: Support extensions in INTRODUCE{1,2}

crates/tor-cell/src/relaycell/hs.rs

@@ -93,6 +93,22 @@ impl Introduce2 {
     }
 }
 
+caret_int! {
+    /// The recognized extension types for an `Introduce1` or `Introduce2 message.
+    #[derive(Ord,PartialOrd)]
+    pub struct IntroduceExtType(u8) {
+    }
+}
+
+decl_extension_group! {
+    /// An extension to an IntroEstablished message.
+    ///
+    /// (Currently, no extensions of this type are recognized)
+    #[derive(Debug,Clone)]
+    enum IntroduceExt [ IntroduceExtType ] {
+    }
+}
+
 #[derive(Debug, Clone)]
 /// A message body shared by Introduce1 and Introduce2
 struct Introduce {
@@ -101,6 +117,8 @@ struct Introduce {
     auth_key_type: AuthKeyType,
     /// The public introduction point auth key.
     auth_key: Vec<u8>,
+    /// A list of extensions
+    extensions: ExtList<IntroduceExt>,
     /// Up to end of relay payload.
     encrypted: Vec<u8>,
 }
@@ -111,6 +129,7 @@ impl Introduce {
         Self {
             auth_key_type,
             auth_key,
+            extensions: Default::default(),
             encrypted,
         }
     }
@@ -125,18 +144,12 @@ impl Introduce {
         let auth_key_type = r.take_u8()?.into();
         let auth_key_len = r.take_u16()?;
         let auth_key = r.take(auth_key_len as usize)?.into();
-        let n_ext = r.take_u8()?;
-        for _ in 0..n_ext {
-            let _ext_type = r.take_u8()?;
-            r.read_nested_u8len(|r| {
-                r.take_rest();
-                Ok(())
-            })?;
-        }
+        let extensions = r.extract()?;
         let encrypted = r.take_rest().into();
         Ok(Self {
             auth_key_type,
             auth_key,
+            extensions,
             encrypted,
         })
     }
@@ -146,8 +159,7 @@ impl Introduce {
         w.write_u8(self.auth_key_type.get());
         w.write_u16(u16::try_from(self.auth_key.len()).map_err(|_| EncodeError::BadLengthValue)?);
         w.write_all(&self.auth_key[..]);
-        // No Introduce1 extension for now.
-        w.write_u8(0_u8);
+        w.write(&self.extensions)?;
         w.write_all(&self.encrypted[..]);
         Ok(())
     }

crates/tor-cell/tests/testvec_relaymsg.rs

@@ -717,10 +717,7 @@ fn test_establish_intro() {
 #[cfg(feature = "hs-service")]
 #[test]
 fn test_introduce() {
-    use tor_cell::relaycell::{
-        hs::{AuthKeyType, Introduce1},
-        msg::AnyRelayMsg,
-    };
+    use tor_cell::relaycell::hs::{AuthKeyType, Introduce1};
 
     // Testing with Introduce1 only should be sufficient as long as
     // Introduce1 and Introduce2 share the same inner body
@@ -738,7 +735,7 @@ fn test_introduce() {
          02 0004 00010203
          00
          01090804",
-        &intro1.clone().into(),
+        &intro1.into(),
     );
 
     // Introduce1 with unknown extensions
@@ -747,16 +744,11 @@ fn test_introduce() {
          02 01 01 00 02 01 00
          01090804";
     let actual_msg = decode(cmd, &unhex(body)[..]).unwrap();
-    let mut actual_bytes = vec![];
-    let mut expect_bytes = vec![];
+    let mut actual_bytes = Vec::new();
     actual_msg
         .encode_onto(&mut actual_bytes)
         .expect("Encode msg onto byte vector");
-    let expected_msg: AnyRelayMsg = intro1.into();
-    expected_msg
-        .encode_onto(&mut expect_bytes)
-        .expect("Encode msg onto byte vector");
-    assert_eq!(actual_bytes, expect_bytes);
+    assert_eq!(actual_bytes, unhex(body));
 
     // Introduce1 with legacy key id
     msg_error(