Add a bunch of work-in-progress comments for 15056 planning

src/or/channel.h

@@ -153,13 +153,23 @@ struct channel_s {
   int (*write_var_cell)(channel_t *, var_cell_t *);
 
   /**
-   * Hash of the public RSA key for the other side's RSA identity key, or
+   * Hash of the public RSA key for the other side's RSA identity key -- or
-   * zeroes if the other side hasn't shown us a valid RSA identity key.
+   * zeroes if we don't have an RSA identity in mind for the other side, and
+   * it hasn't shown us one.
+   *
+   * Note that this is the RSA identity that we hope the other side has -- not
+   * necessarily its true identity.  Don't believe this identity unless
+   * authentication has happened.
    */
   char identity_digest[DIGEST_LEN];
   /**
-   * The Ed25519 public identity key for the other side, or zeros if the other
+   * Ed25519 key for the other side of this channel -- or zeroes if we don't
-   * size hasn't shown us a valid Ed25519 identity key
+   * have an Ed25519 identity in mind for the other side, and it hasn't shown
+   * us one.
+   *
+   * Note that this is the identity that we hope the other side has -- not
+   * necessarily its true identity.  Don't believe this identity unless
+   * authentication has happened.
    */
   ed25519_public_key_t ed25519_identity;
 
@@ -167,8 +177,8 @@ struct channel_s {
   char *nickname;
 
   /**
-   * Linked list of channels with the same identity digest, for the
+   * Linked list of channels with the same RSA identity digest, for use with
-   * digest->channel map
+   * the digest->channel map
    */
   TOR_LIST_ENTRY(channel_s) next_with_same_id;
 

src/or/channeltls.c

@@ -1651,9 +1651,10 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
         connection_or_init_conn_from_address(chan->conn,
                   &(chan->conn->base_.addr),
                   chan->conn->base_.port,
+                  /* zero, checked above */
                   (const char*)(chan->conn->handshake_state->
                                 authenticated_rsa_peer_id),
-                  NULL, // XXXX Ed key
+                  NULL, /* Ed25519 ID: Also checked as zero */
                   0);
       }
     }

src/or/circuitbuild.c

@@ -1185,6 +1185,10 @@ circuit_extend(cell_t *cell, circuit_t *circ)
            "Client asked me to extend back to the previous hop.");
     return -1;
   }
+  // XXX 15056 check prev-hop Ed ID too
+
+  // XXX 15056 Fill in ed_pubkey if it was not provided and we can infer
+  // XXX 15056 it from the networkstatus.
 
   n_chan = channel_get_for_extend((const char*)ec.node_id,
                                   &ec.ed_pubkey,

src/or/connection_or.c

@@ -80,7 +80,7 @@ static void connection_or_change_state(or_connection_t *conn, uint8_t state);
 /** Map from identity digest of connected OR or desired OR to a connection_t
  * with that identity digest.  If there is more than one such connection_t,
  * they form a linked list, with next_with_same_id as the next pointer. */
-static digestmap_t *orconn_identity_map = NULL;
+static digestmap_t *orconn_identity_map = NULL; // XXXX 15056 disused.
 
 /** Global map between Extended ORPort identifiers and OR
  *  connections. */
@@ -883,7 +883,7 @@ connection_or_init_conn_from_address(or_connection_t *conn,
                                      const ed25519_public_key_t *ed_id,
                                      int started_here)
 {
-  (void) ed_id; // not fully used yet.
+  (void) ed_id; // not fully used yet. 15056
   const node_t *r = node_get_by_id(id_digest);
   connection_or_set_identity_digest(conn, id_digest, ed_id);
   connection_or_update_token_buckets_helper(conn, 1, get_options());
@@ -981,6 +981,9 @@ connection_or_mark_bad_for_new_circs(or_connection_t *or_conn)
 static void
 connection_or_group_set_badness(or_connection_t *head, int force)
 {
+  // XXXX 15056 we should make this about channels instead, so we
+  //            can finally remove orconn_identity_map.
+
   or_connection_t *or_conn = NULL, *best = NULL;
   int n_old = 0, n_inprogress = 0, n_canonical = 0, n_other = 0;
   time_t now = time(NULL);
@@ -1109,6 +1112,9 @@ connection_or_set_bad_connections(const char *digest, int force)
   if (!orconn_identity_map)
     return;
 
+  // XXXX This is just about the only remaining user of orconn_identity_map!
+  // XXXX If we kill it, we can yoink out the map. 15056.
+
   DIGESTMAP_FOREACH(orconn_identity_map, identity, or_connection_t *, conn) {
     if (!digest || tor_memeq(digest, conn->identity_digest, DIGEST_LEN))
       connection_or_group_set_badness(conn, force);
@@ -1573,7 +1579,7 @@ connection_or_check_valid_tls_handshake(or_connection_t *conn,
   if (started_here)
     return connection_or_client_learned_peer_id(conn,
                                         (const uint8_t*)digest_rcvd_out,
-                                        NULL // Ed25519 ID
+                                        NULL // Ed25519 ID 15056
                                         );
 
   return 0;
@@ -1607,7 +1613,7 @@ connection_or_client_learned_peer_id(or_connection_t *conn,
                                      const uint8_t *rsa_peer_id,
                                      const ed25519_public_key_t *ed_peer_id)
 {
-  (void) ed_peer_id; // not used yet.
+  (void) ed_peer_id; // not used yet. 15056
 
   const or_options_t *options = get_options();
 
@@ -1685,7 +1691,7 @@ connection_or_client_learned_peer_id(or_connection_t *conn,
   }
   if (authdir_mode_tests_reachability(options)) {
     dirserv_orconn_tls_done(&conn->base_.addr, conn->base_.port,
-                            (const char*)rsa_peer_id /*, ed_id XXXX */);
+                            (const char*)rsa_peer_id /*, ed_id XXXX 15056 */);
   }
 
   return 0;