tor-netdoc: Remove redundant `IntroPointDesc` struct.

This commit replaces `tor_netdoc::hsdesc::inner::IntroPointDesc` with
the (almost identical) `tor_netdoc::hsdesc::IntroPointDesc`.

The only difference between the two structs is that
`inner::IntroPointDesc` wraps a `Vec<LinkSpec>` instead of a
`Vec<EncodedLinkSpec>`. Since `EncodedLinkSpec` can be derived from
`LinkSpec` (and vice-versa), and since `hsdesc::inner::IntroPointDesc`
never made it in our public API, this commit also removes
`hsdesc::inner::IntroPointDesc` in favour of `hsdesc::IntroPointDesc`.

crates/tor-netdoc/semver.md

@@ -0,0 +1,3 @@
+BREAKING: The argument of `HsDescBuilder::intro_points` is now
+`tor_netdoc::hsdesc::IntroPointDesc` instead of the private
+`tor_netdoc::hsdesc::builder::inner:IntroPointDesc`

crates/tor-netdoc/src/doc/hsdesc/build.rs

@@ -4,7 +4,7 @@ mod inner;
 mod middle;
 mod outer;
 
-use crate::doc::hsdesc::IntroAuthType;
+use crate::doc::hsdesc::{IntroAuthType, IntroPointDesc};
 use crate::NetdocBuilder;
 use rand::{CryptoRng, RngCore};
 use tor_bytes::EncodeError;
@@ -21,7 +21,7 @@ use smallvec::SmallVec;
 use std::borrow::{Borrow, Cow};
 use std::time::SystemTime;
 
-use self::inner::{HsDescInner, IntroPointDesc};
+use self::inner::HsDescInner;
 use self::middle::HsDescMiddle;
 use self::outer::HsDescOuter;
 
@@ -286,6 +286,12 @@ mod test {
         rng: &mut R,
         link_specifiers: Vec<LinkSpec>,
     ) -> IntroPointDesc {
+        let link_specifiers = link_specifiers
+            .iter()
+            .map(|link_spec| link_spec.encode())
+            .collect::<Result<Vec<_>, _>>()
+            .unwrap();
+
         IntroPointDesc {
             link_specifiers,
             ipt_ntor_key: create_curve25519_pk(rng),
@@ -354,7 +360,9 @@ mod test {
         let expiry = SystemTime::now() + Duration::from_secs(CERT_EXPIRY_SECS);
         let mut rng = Config::Deterministic.into_rng().rng_compat();
         let intro_points = vec![IntroPointDesc {
-            link_specifiers: vec![LinkSpec::OrPort(Ipv4Addr::LOCALHOST.into(), 9999)],
+            link_specifiers: vec![LinkSpec::OrPort(Ipv4Addr::LOCALHOST.into(), 9999)
+                .encode()
+                .unwrap()],
             ipt_ntor_key: create_curve25519_pk(&mut rng),
             ipt_sid_key: ed25519::Keypair::generate(&mut rng).public.into(),
             svc_ntor_key: create_curve25519_pk(&mut rng).into(),

crates/tor-netdoc/src/doc/hsdesc/build/inner.rs

@@ -7,6 +7,7 @@
 use crate::build::NetdocEncoder;
 use crate::doc::hsdesc::inner::HsInnerKwd;
 use crate::doc::hsdesc::IntroAuthType;
+use crate::doc::hsdesc::IntroPointDesc;
 use crate::NetdocBuilder;
 
 use rand::CryptoRng;
@@ -14,11 +15,8 @@ use rand::RngCore;
 use tor_bytes::{EncodeError, Writer};
 use tor_cert::{CertType, CertifiedKey, Ed25519Cert};
 use tor_error::{bad_api_usage, into_bad_api_usage};
-use tor_hscrypto::pk::HsIntroPtSessionIdKey;
-use tor_hscrypto::pk::HsSvcNtorKey;
-use tor_linkspec::LinkSpec;
+use tor_llcrypto::pk::ed25519;
 use tor_llcrypto::pk::keymanip::convert_curve25519_to_ed25519_public;
-use tor_llcrypto::pk::{curve25519, ed25519};
 
 use base64ct::{Base64, Encoding};
 
@@ -48,32 +46,6 @@ pub(super) struct HsDescInner<'a> {
     pub(super) intro_enc_key_cert_expiry: SystemTime,
 }
 
-/// Information in an onion service descriptor about a single introduction point.
-///
-/// TODO HSS: Move out of tor-netdoc: this is a general-purpose representation of an introduction
-/// point, not merely an intermediate representation for decoding/encoding. There may be other
-/// types that need to be factored out tor-netdoc for the same reason.
-#[derive(Debug, Clone)]
-pub struct IntroPointDesc {
-    /// A list of link specifiers needed to extend a circuit to the introduction point.
-    ///
-    /// These can include public keys and network addresses.
-    pub(crate) link_specifiers: Vec<LinkSpec>,
-    /// The key used to extend a circuit _to the introduction point_, using the
-    /// ntor or ntor3 handshakes.  (`KP_ntor`)
-    pub(crate) ipt_ntor_key: curve25519::PublicKey,
-    /// A key used to identify the onion service at this introduction point.
-    /// (`KP_hs_ipt_sid`)
-    pub(crate) ipt_sid_key: HsIntroPtSessionIdKey,
-    /// `KP_hss_ntor`, the key used to encrypt a handshake _to the onion
-    /// service_ when using this introduction point.
-    ///
-    /// The onion service uses a separate key of this type with each
-    /// introduction point as part of its strategy for preventing replay
-    /// attacks.
-    pub(crate) svc_ntor_key: HsSvcNtorKey,
-}
-
 impl<'a> NetdocBuilder for HsDescInner<'a> {
     fn build_sign<R: RngCore + CryptoRng>(self, _: &mut R) -> Result<String, EncodeError> {
         use HsInnerKwd::*;