circ: Remove n_mux and p_mux members

They are simply not used apart from assigning a pointer and asserting on the
pointer depending on the cell direction.

Closes #29196.

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/core/or/circuit_st.h

@@ -66,12 +66,6 @@ struct circuit_t {
    */
   circid_t n_circ_id;
 
-  /**
-   * Circuit mux associated with n_chan to which this circuit is attached;
-   * NULL if we have no n_chan.
-   */
-  circuitmux_t *n_mux;
-
   /** Queue of cells waiting to be transmitted on n_chan */
   cell_queue_t n_chan_cells;
 

src/core/or/circuitlist.c

@@ -2433,13 +2433,9 @@ marked_circuit_free_cells(circuit_t *circ)
     return;
   }
   cell_queue_clear(&circ->n_chan_cells);
-  if (circ->n_mux)
-    circuitmux_clear_num_cells(circ->n_mux, circ);
   if (! CIRCUIT_IS_ORIGIN(circ)) {
     or_circuit_t *orcirc = TO_OR_CIRCUIT(circ);
     cell_queue_clear(&orcirc->p_chan_cells);
-    if (orcirc->p_mux)
-      circuitmux_clear_num_cells(orcirc->p_mux, circ);
   }
 }
 

src/core/or/circuitmux.c

@@ -294,9 +294,6 @@ circuitmux_detach_all_circuits(circuitmux_t *cmux, smartlist_t *detached_out)
               circuitmux_make_circuit_inactive(cmux, circ);
             }
 
-            /* Clear n_mux */
-            circ->n_mux = NULL;
-
             if (detached_out)
               smartlist_add(detached_out, circ);
           } else if (circ->magic == OR_CIRCUIT_MAGIC) {
@@ -309,12 +306,6 @@ circuitmux_detach_all_circuits(circuitmux_t *cmux, smartlist_t *detached_out)
               circuitmux_make_circuit_inactive(cmux, circ);
             }
 
-            /*
-             * It has a sensible p_chan and direction == CELL_DIRECTION_IN,
-             * so clear p_mux.
-             */
-            TO_OR_CIRCUIT(circ)->p_mux = NULL;
-
             if (detached_out)
               smartlist_add(detached_out, circ);
           } else {
@@ -836,18 +827,14 @@ circuitmux_attach_circuit,(circuitmux_t *cmux, circuit_t *circ,
      */
     log_info(LD_CIRC,
              "Circuit %u on channel %"PRIu64 " was already attached to "
-             "cmux %p (trying to attach to %p)",
+             "(trying to attach to %p)",
              (unsigned)circ_id, (channel_id),
-             ((direction == CELL_DIRECTION_OUT) ?
-                circ->n_mux : TO_OR_CIRCUIT(circ)->p_mux),
              cmux);
 
     /*
      * The mux pointer on this circuit and the direction in result should
      * match; otherwise assert.
      */
-    if (direction == CELL_DIRECTION_OUT) tor_assert(circ->n_mux == cmux);
-    else tor_assert(TO_OR_CIRCUIT(circ)->p_mux == cmux);
     tor_assert(hashent->muxinfo.direction == direction);
 
     /*
@@ -872,13 +859,6 @@ circuitmux_attach_circuit,(circuitmux_t *cmux, circuit_t *circ,
              "Attaching circuit %u on channel %"PRIu64 " to cmux %p",
               (unsigned)circ_id, (channel_id), cmux);
 
-    /*
-     * Assert that the circuit doesn't already have a mux for this
-     * direction.
-     */
-    if (direction == CELL_DIRECTION_OUT) tor_assert(circ->n_mux == NULL);
-    else tor_assert(TO_OR_CIRCUIT(circ)->p_mux == NULL);
-
     /* Insert it in the map */
     hashent = tor_malloc_zero(sizeof(*hashent));
     hashent->chan_id = channel_id;
@@ -902,10 +882,6 @@ circuitmux_attach_circuit,(circuitmux_t *cmux, circuit_t *circ,
     HT_INSERT(chanid_circid_muxinfo_map, cmux->chanid_circid_map,
               hashent);
 
-    /* Set the circuit's mux for this direction */
-    if (direction == CELL_DIRECTION_OUT) circ->n_mux = cmux;
-    else TO_OR_CIRCUIT(circ)->p_mux = cmux;
-
     /* Update counters */
     ++(cmux->n_circuits);
     if (cell_count > 0) {
@@ -993,9 +969,6 @@ circuitmux_detach_circuit,(circuitmux_t *cmux, circuit_t *circ))
 
     /* Consistency check: the direction must match the direction searched */
     tor_assert(last_searched_direction == hashent->muxinfo.direction);
-    /* Clear the circuit's mux for this direction */
-    if (last_searched_direction == CELL_DIRECTION_OUT) circ->n_mux = NULL;
-    else TO_OR_CIRCUIT(circ)->p_mux = NULL;
 
     /* Now remove it from the map */
     HT_REMOVE(chanid_circid_muxinfo_map, cmux->chanid_circid_map, hashent);

src/core/or/or_circuit_st.h

@@ -33,11 +33,6 @@ struct or_circuit_t {
   cell_queue_t p_chan_cells;
   /** The channel that is previous in this circuit. */
   channel_t *p_chan;
-  /**
-   * Circuit mux associated with p_chan to which this circuit is attached;
-   * NULL if we have no p_chan.
-   */
-  circuitmux_t *p_mux;
   /** Linked list of Exit streams associated with this circuit. */
   edge_connection_t *n_streams;
   /** Linked list of Exit streams associated with this circuit that are

src/test/test_channel.c

@@ -598,7 +598,6 @@ test_channel_outbound_cell(void *arg)
   circuit_set_n_circid_chan(TO_CIRCUIT(circ), 42, chan);
   tt_int_op(channel_num_circuits(chan), OP_EQ, 1);
   /* Test the cmux state. */
-  tt_ptr_op(TO_CIRCUIT(circ)->n_mux, OP_EQ, chan->cmux);
   tt_int_op(circuitmux_is_circuit_attached(chan->cmux, TO_CIRCUIT(circ)),
             OP_EQ, 1);
 

src/test/test_circuitpadding.c

@@ -116,7 +116,6 @@ new_fake_orcirc(channel_t *nchan, channel_t *pchan)
 
   //circ->n_chan = nchan;
   circ->n_circ_id = get_unique_circ_id_by_chan(nchan);
-  circ->n_mux = NULL; /* ?? */
   cell_queue_init(&(circ->n_chan_cells));
   circ->n_hop = NULL;
   circ->streams_blocked_on_n_chan = 0;