docs: add & update rustdoc comments

rtc_data_enclave/src/lib.rs

@@ -56,8 +56,9 @@ pub unsafe extern "C" fn validate_and_save(
     }
 }
 
-/// Tries to perform local attestation to an enclave at dest_enclave_id. The enclave needs to be
-/// initialized as a `ResponderSys` in rtc_udh'
+/// Tries to perform local attestation to an enclave at dest_enclave_id.
+///
+/// See: [`DhSessions::establish_new`]
 #[no_mangle]
 pub unsafe extern "C" fn local_attestation(dest_enclave_id: sgx_enclave_id_t) -> sgx_status_t {
     let res = rtc_tenclave::dh::dh_sessions().establish_new(dest_enclave_id);

rtc_tenclave/src/dh/mod.rs

@@ -1,3 +1,5 @@
+//! Support for establishing secure local inter-enclave sessions using [`sgx_tdh`].
+
 mod protected_channel;
 mod sessions;
 mod types;
@@ -6,6 +8,8 @@ pub use sessions::*;
 
 #[cfg(test)]
 mod enclave {
+    //! Stub [`sgx_tstd::enclave`] for testing.
+
     use sgx_types::sgx_enclave_id_t;
 
     pub fn get_enclave_id() -> sgx_enclave_id_t {

rtc_tenclave/src/dh/protected_channel.rs

@@ -1,3 +1,5 @@
+//! Secure symmetric communication channels based on [`sgx_tcrypto`]'s AES-GCM.
+
 use secrecy::{ExposeSecret, Secret};
 use sgx_tcrypto::{rsgx_rijndael128GCM_decrypt, rsgx_rijndael128GCM_encrypt};
 use sgx_types::*;

rtc_tenclave/src/dh/sessions.rs

@@ -147,6 +147,9 @@ where
         Ok(())
     }
 
+    /// Attest and establish a new active session between this enclave and `dest_enclave_id`.
+    ///
+    /// The responding enclave must be registered using [`rtc_udh::set_responder`].
     pub fn establish_new(
         &self,
         dest_enclave_id: sgx_enclave_id_t,

rtc_udh/src/lib.rs

@@ -23,6 +23,7 @@ fn dh_responders() -> &'static RwLock<DhResponders> {
     DH_RESPONDERS.get_or_init(|| RwLock::new(HashMap::new()))
 }
 
+/// Register enclave as a DH responder.
 pub fn set_responder(
     enclave_id: sgx_enclave_id_t,
     responder: Box<(dyn ResponderSys + 'static)>,
@@ -39,6 +40,7 @@ pub fn set_responder(
     }
 }
 
+/// Retrieve enclave's registered responder.
 fn get_responder(enclave_id: sgx_enclave_id_t) -> Result<SyncSendResponder, sgx_status_t> {
     dh_responders()
         .read()