Use channel_t rather than or_connection_t for circuits

9 files changed, 446 insertions, 328 deletions

diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 56c2c22d01..5ef67bd9df 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -12,9 +12,11 @@
 #define CIRCUIT_PRIVATE
 
 #include "or.h"
+#include "channel.h"
 #include "circuitbuild.h"
 #include "circuitlist.h"
 #include "circuituse.h"
+#include "command.h"
 #include "config.h"
 #include "confparse.h"
 #include "connection.h"
@@ -125,6 +127,9 @@ static int unit_tests = 0;
 
 /********* END VARIABLES ************/
 
+static channel_t * channel_connect_for_circuit(const tor_addr_t *addr,
+                                               uint16_t port,
+                                               const char *id_digest);
 static int circuit_deliver_create_cell(circuit_t *circ,
                                        uint8_t cell_type, const char *payload);
 static int onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit);
@@ -141,6 +146,22 @@ static void bridge_free(bridge_info_t *bridge);
 static int entry_guard_inc_first_hop_count(entry_guard_t *guard);
 static void pathbias_count_success(origin_circuit_t *circ);
 
+/** This function tries to get a channel to the specified endpoint,
+ * and then calls command_setup_channel() to give it the right
+ * callbacks.
+ */
+static channel_t *
+channel_connect_for_circuit(const tor_addr_t *addr, uint16_t port,
+                            const char *id_digest)
+{
+  channel_t *chan;
+
+  chan = channel_connect(addr, port, id_digest);
+  if (chan) command_setup_channel(chan);
+
+  return chan;
+}
+
 /**
  * This function decides if CBT learning should be disabled. It returns
  * true if one or more of the following four conditions are met:
@@ -1683,26 +1704,30 @@ circuit_build_times_set_timeout(circuit_build_times_t *cbt)
  * Return it, or 0 if can't get a unique circ_id.
  */
 static circid_t
-get_unique_circ_id_by_conn(or_connection_t *conn)
+get_unique_circ_id_by_chan(channel_t *chan)
 {
   circid_t test_circ_id;
   circid_t attempts=0;
   circid_t high_bit;
 
-  tor_assert(conn);
-  if (conn->circ_id_type == CIRC_ID_TYPE_NEITHER) {
-    log_warn(LD_BUG, "Trying to pick a circuit ID for a connection from "
+  tor_assert(chan);
+  tor_assert(!(chan->is_listener));
+
+  if (chan->u.cell_chan.circ_id_type == CIRC_ID_TYPE_NEITHER) {
+    log_warn(LD_BUG,
+             "Trying to pick a circuit ID for a connection from "
              "a client with no identity.");
     return 0;
   }
-  high_bit = (conn->circ_id_type == CIRC_ID_TYPE_HIGHER) ? 1<<15 : 0;
+  high_bit =
+    (chan->u.cell_chan.circ_id_type == CIRC_ID_TYPE_HIGHER) ? 1<<15 : 0;
   do {
     /* Sequentially iterate over test_circ_id=1...1<<15-1 until we find a
      * circID such that (high_bit|test_circ_id) is not already used. */
-    test_circ_id = conn->next_circ_id++;
+    test_circ_id = chan->u.cell_chan.next_circ_id++;
     if (test_circ_id == 0 || test_circ_id >= 1<<15) {
       test_circ_id = 1;
-      conn->next_circ_id = 2;
+      chan->u.cell_chan.next_circ_id = 2;
     }
     if (++attempts > 1<<15) {
       /* Make sure we don't loop forever if all circ_id's are used. This
@@ -1712,7 +1737,7 @@ get_unique_circ_id_by_conn(or_connection_t *conn)
       return 0;
     }
     test_circ_id |= high_bit;
-  } while (circuit_id_in_use_on_orconn(test_circ_id, conn));
+  } while (circuit_id_in_use_on_channel(test_circ_id, chan));
   return test_circ_id;
 }
 
@@ -1891,9 +1916,9 @@ onion_populate_cpath(origin_circuit_t *circ)
 origin_circuit_t *
 origin_circuit_init(uint8_t purpose, int flags)
 {
-  /* sets circ->p_circ_id and circ->p_conn */
+  /* sets circ->p_circ_id and circ->p_chan */
   origin_circuit_t *circ = origin_circuit_new();
-  circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OR_WAIT);
+  circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_CHAN_WAIT);
   circ->build_state = tor_malloc_zero(sizeof(cpath_build_state_t));
   circ->build_state->onehop_tunnel =
     ((flags & CIRCLAUNCH_ONEHOP_TUNNEL) ? 1 : 0);
@@ -1945,7 +1970,7 @@ int
 circuit_handle_first_hop(origin_circuit_t *circ)
 {
   crypt_path_t *firsthop;
-  or_connection_t *n_conn;
+  channel_t *n_chan;
   int err_reason = 0;
   const char *msg = NULL;
   int should_launch = 0;
@@ -1959,12 +1984,12 @@ circuit_handle_first_hop(origin_circuit_t *circ)
             fmt_addr(&firsthop->extend_info->addr),
             firsthop->extend_info->port);
 
-  n_conn = connection_or_get_for_extend(firsthop->extend_info->identity_digest,
-                                        &firsthop->extend_info->addr,
-                                        &msg,
-                                        &should_launch);
+  n_chan = channel_get_for_extend(firsthop->extend_info->identity_digest,
+                                  &firsthop->extend_info->addr,
+                                  &msg,
+                                  &should_launch);
 
-  if (!n_conn) {
+  if (!n_chan) {
     /* not currently connected in a useful way. */
     log_info(LD_CIRC, "Next router is %s: %s",
              safe_str_client(extend_info_describe(firsthop->extend_info)),
@@ -1974,10 +1999,11 @@ circuit_handle_first_hop(origin_circuit_t *circ)
     if (should_launch) {
       if (circ->build_state->onehop_tunnel)
         control_event_bootstrap(BOOTSTRAP_STATUS_CONN_DIR, 0);
-      n_conn = connection_or_connect(&firsthop->extend_info->addr,
-                                     firsthop->extend_info->port,
-                                     firsthop->extend_info->identity_digest);
-      if (!n_conn) { /* connect failed, forget the whole thing */
+      n_chan = channel_connect_for_circuit(
+          &firsthop->extend_info->addr,
+          firsthop->extend_info->port,
+          firsthop->extend_info->identity_digest);
+      if (!n_chan) { /* connect failed, forget the whole thing */
         log_info(LD_CIRC,"connect to firsthop failed. Closing.");
         return -END_CIRC_REASON_CONNECTFAILED;
       }
@@ -1985,13 +2011,13 @@ circuit_handle_first_hop(origin_circuit_t *circ)
 
     log_debug(LD_CIRC,"connecting in progress (or finished). Good.");
     /* return success. The onion/circuit/etc will be taken care of
-     * automatically (may already have been) whenever n_conn reaches
+     * automatically (may already have been) whenever n_chan reaches
      * OR_CONN_STATE_OPEN.
      */
     return 0;
   } else { /* it's already open. use it. */
     tor_assert(!circ->_base.n_hop);
-    circ->_base.n_conn = n_conn;
+    circ->_base.n_chan = n_chan;
     log_debug(LD_CIRC,"Conn open. Delivering first onion skin.");
     if ((err_reason = circuit_send_next_onion_skin(circ)) < 0) {
       log_info(LD_CIRC,"circuit_send_next_onion_skin failed.");
@@ -2007,48 +2033,51 @@ circuit_handle_first_hop(origin_circuit_t *circ)
  * Status is 1 if connect succeeded, or 0 if connect failed.
  */
 void
-circuit_n_conn_done(or_connection_t *or_conn, int status)
+circuit_n_chan_done(channel_t *chan, int status)
 {
   smartlist_t *pending_circs;
   int err_reason = 0;
 
-  log_debug(LD_CIRC,"or_conn to %s/%s, status=%d",
-            or_conn->nickname ? or_conn->nickname : "NULL",
-            or_conn->_base.address, status);
+  tor_assert(chan);
+  tor_assert(!(chan->is_listener));
+
+  log_debug(LD_CIRC,"chan to %s/%s, status=%d",
+            chan->u.cell_chan.nickname ?
+              chan->u.cell_chan.nickname : "NULL",
+            channel_get_canonical_remote_descr(chan), status);
 
   pending_circs = smartlist_new();
-  circuit_get_all_pending_on_or_conn(pending_circs, or_conn);
+  circuit_get_all_pending_on_channel(pending_circs, chan);
 
   SMARTLIST_FOREACH_BEGIN(pending_circs, circuit_t *, circ)
     {
       /* These checks are redundant wrt get_all_pending_on_or_conn, but I'm
        * leaving them in in case it's possible for the status of a circuit to
        * change as we're going down the list. */
-      if (circ->marked_for_close || circ->n_conn || !circ->n_hop ||
-          circ->state != CIRCUIT_STATE_OR_WAIT)
+      if (circ->marked_for_close || circ->n_chan || !circ->n_hop ||
+          circ->state != CIRCUIT_STATE_CHAN_WAIT)
         continue;
 
       if (tor_digest_is_zero(circ->n_hop->identity_digest)) {
         /* Look at addr/port. This is an unkeyed connection. */
-        if (!tor_addr_eq(&circ->n_hop->addr, &or_conn->_base.addr) ||
-            circ->n_hop->port != or_conn->_base.port)
+        if (!channel_matches_extend_info(chan, circ->n_hop))
           continue;
       } else {
         /* We expected a key. See if it's the right one. */
-        if (tor_memneq(or_conn->identity_digest,
+        if (tor_memneq(chan->u.cell_chan.identity_digest,
                    circ->n_hop->identity_digest, DIGEST_LEN))
           continue;
       }
-      if (!status) { /* or_conn failed; close circ */
-        log_info(LD_CIRC,"or_conn failed. Closing circ.");
-        circuit_mark_for_close(circ, END_CIRC_REASON_OR_CONN_CLOSED);
+      if (!status) { /* chan failed; close circ */
+        log_info(LD_CIRC,"Channel failed; closing circ.");
+        circuit_mark_for_close(circ, END_CIRC_REASON_CHANNEL_CLOSED);
         continue;
       }
       log_debug(LD_CIRC, "Found circ, sending create cell.");
       /* circuit_deliver_create_cell will set n_circ_id and add us to
-       * orconn_circuid_circuit_map, so we don't need to call
-       * set_circid_orconn here. */
-      circ->n_conn = or_conn;
+       * chan_circuid_circuit_map, so we don't need to call
+       * set_circid_chan here. */
+      circ->n_chan = chan;
       extend_info_free(circ->n_hop);
       circ->n_hop = NULL;
 
@@ -2064,13 +2093,13 @@ circuit_n_conn_done(or_connection_t *or_conn, int status)
         }
       } else {
         /* pull the create cell out of circ->onionskin, and send it */
-        tor_assert(circ->n_conn_onionskin);
+        tor_assert(circ->n_chan_onionskin);
         if (circuit_deliver_create_cell(circ,CELL_CREATE,
-                                        circ->n_conn_onionskin)<0) {
+                                        circ->n_chan_onionskin)<0) {
           circuit_mark_for_close(circ, END_CIRC_REASON_RESOURCELIMIT);
           continue;
         }
-        tor_free(circ->n_conn_onionskin);
+        tor_free(circ->n_chan_onionskin);
         circuit_set_state(circ, CIRCUIT_STATE_OPEN);
       }
     }
@@ -2079,7 +2108,7 @@ circuit_n_conn_done(or_connection_t *or_conn, int status)
   smartlist_free(pending_circs);
 }
 
-/** Find a new circid that isn't currently in use on the circ->n_conn
+/** Find a new circid that isn't currently in use on the circ->n_chan
  * for the outgoing
  * circuit <b>circ</b>, and deliver a cell of type <b>cell_type</b>
  * (either CELL_CREATE or CELL_CREATE_FAST) with payload <b>payload</b>
@@ -2094,29 +2123,29 @@ circuit_deliver_create_cell(circuit_t *circ, uint8_t cell_type,
   circid_t id;
 
   tor_assert(circ);
-  tor_assert(circ->n_conn);
+  tor_assert(circ->n_chan);
   tor_assert(payload);
   tor_assert(cell_type == CELL_CREATE || cell_type == CELL_CREATE_FAST);
 
-  id = get_unique_circ_id_by_conn(circ->n_conn);
+  id = get_unique_circ_id_by_chan(circ->n_chan);
   if (!id) {
     log_warn(LD_CIRC,"failed to get unique circID.");
     return -1;
   }
   log_debug(LD_CIRC,"Chosen circID %u.", id);
-  circuit_set_n_circid_orconn(circ, id, circ->n_conn);
+  circuit_set_n_circid_chan(circ, id, circ->n_chan);
 
   memset(&cell, 0, sizeof(cell_t));
   cell.command = cell_type;
   cell.circ_id = circ->n_circ_id;
 
   memcpy(cell.payload, payload, ONIONSKIN_CHALLENGE_LEN);
-  append_cell_to_circuit_queue(circ, circ->n_conn, &cell,
+  append_cell_to_circuit_queue(circ, circ->n_chan, &cell,
                                CELL_DIRECTION_OUT, 0);
 
   if (CIRCUIT_IS_ORIGIN(circ)) {
     /* mark it so it gets better rate limiting treatment. */
-    circ->n_conn->client_used = time(NULL);
+    channel_timestamp_client(circ->n_chan);
   }
 
   return 0;
@@ -2218,7 +2247,8 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
     else
       control_event_bootstrap(BOOTSTRAP_STATUS_CIRCUIT_CREATE, 0);
 
-    node = node_get_by_id(circ->_base.n_conn->identity_digest);
+    tor_assert(!(circ->_base.n_chan->is_listener));
+    node = node_get_by_id(circ->_base.n_chan->u.cell_chan.identity_digest);
     fast = should_use_create_fast_for_circuit(circ);
     if (!fast) {
       /* We are an OR and we know the right onion key: we should
@@ -2386,7 +2416,7 @@ circuit_note_clock_jumped(int seconds_elapsed)
 int
 circuit_extend(cell_t *cell, circuit_t *circ)
 {
-  or_connection_t *n_conn;
+  channel_t *n_chan;
   relay_header_t rh;
   char *onionskin;
   char *id_digest=NULL;
@@ -2396,9 +2426,9 @@ circuit_extend(cell_t *cell, circuit_t *circ)
   const char *msg = NULL;
   int should_launch = 0;
 
-  if (circ->n_conn) {
+  if (circ->n_chan) {
     log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
-           "n_conn already set. Bug/attack. Closing.");
+           "n_chan already set. Bug/attack. Closing.");
     return -1;
   }
   if (circ->n_hop) {
@@ -2457,19 +2487,22 @@ circuit_extend(cell_t *cell, circuit_t *circ)
   /* Next, check if we're being asked to connect to the hop that the
    * extend cell came from. There isn't any reason for that, and it can
    * assist circular-path attacks. */
-  if (tor_memeq(id_digest, TO_OR_CIRCUIT(circ)->p_conn->identity_digest,
-              DIGEST_LEN)) {
+  tor_assert(!(TO_OR_CIRCUIT(circ)->p_chan->is_listener));
+  if (tor_memeq(id_digest,
+                TO_OR_CIRCUIT(circ)->p_chan->
+                  u.cell_chan.identity_digest,
+                DIGEST_LEN)) {
     log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
            "Client asked me to extend back to the previous hop.");
     return -1;
   }
 
-  n_conn = connection_or_get_for_extend(id_digest,
-                                        &n_addr,
-                                        &msg,
-                                        &should_launch);
+  n_chan = channel_get_for_extend(id_digest,
+                                  &n_addr,
+                                  &msg,
+                                  &should_launch);
 
-  if (!n_conn) {
+  if (!n_chan) {
     log_debug(LD_CIRC|LD_OR,"Next router (%s:%d): %s",
               fmt_addr(&n_addr), (int)n_port, msg?msg:"????");
 
@@ -2478,31 +2511,32 @@ circuit_extend(cell_t *cell, circuit_t *circ)
                                     NULL /*onion_key*/,
                                     &n_addr, n_port);
 
-    circ->n_conn_onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
-    memcpy(circ->n_conn_onionskin, onionskin, ONIONSKIN_CHALLENGE_LEN);
-    circuit_set_state(circ, CIRCUIT_STATE_OR_WAIT);
+    circ->n_chan_onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
+    memcpy(circ->n_chan_onionskin, onionskin, ONIONSKIN_CHALLENGE_LEN);
+    circuit_set_state(circ, CIRCUIT_STATE_CHAN_WAIT);
 
     if (should_launch) {
       /* we should try to open a connection */
-      n_conn = connection_or_connect(&n_addr, n_port, id_digest);
-      if (!n_conn) {
-        log_info(LD_CIRC,"Launching n_conn failed. Closing circuit.");
+      n_chan = channel_connect_for_circuit(&n_addr, n_port, id_digest);
+      if (!n_chan) {
+        log_info(LD_CIRC,"Launching n_chan failed. Closing circuit.");
         circuit_mark_for_close(circ, END_CIRC_REASON_CONNECTFAILED);
         return 0;
       }
       log_debug(LD_CIRC,"connecting in progress (or finished). Good.");
     }
     /* return success. The onion/circuit/etc will be taken care of
-     * automatically (may already have been) whenever n_conn reaches
+     * automatically (may already have been) whenever n_chan reaches
      * OR_CONN_STATE_OPEN.
      */
     return 0;
   }
 
   tor_assert(!circ->n_hop); /* Connection is already established. */
-  circ->n_conn = n_conn;
-  log_debug(LD_CIRC,"n_conn is %s:%u",
-            n_conn->_base.address,n_conn->_base.port);
+  circ->n_chan = n_chan;
+  log_debug(LD_CIRC,
+            "n_chan is %s",
+            channel_get_canonical_remote_descr(n_chan));
 
   if (circuit_deliver_create_cell(circ, CELL_CREATE, onionskin) < 0)
     return -1;
@@ -2699,8 +2733,9 @@ pathbias_count_first_hop(origin_circuit_t *circ)
     if (!circ->has_opened) {
       entry_guard_t *guard;
 
+      tor_assert(!(circ->_base.n_chan->is_listener));
       guard = entry_guard_get_by_id_digest(
-              circ->_base.n_conn->identity_digest);
+                circ->_base.n_chan->u.cell_chan.identity_digest);
       if (guard) {
         if (circ->path_state == PATH_STATE_NEW_CIRC) {
           circ->path_state = PATH_STATE_DID_FIRST_HOP;
@@ -2770,6 +2805,7 @@ pathbias_count_success(origin_circuit_t *circ)
   static ratelim_t success_notice_limit =
     RATELIM_INIT(SUCCESS_NOTICE_INTERVAL);
   char *rate_msg = NULL;
+  entry_guard_t *guard = NULL;
 
   /* We can't do path bias accounting without entry guards.
    * Testing and controller circuits also have no guards. */
@@ -2804,8 +2840,10 @@ pathbias_count_success(origin_circuit_t *circ)
 
   /* Don't count cannibalized/reused circs for path bias */
   if (!circ->has_opened) {
-    entry_guard_t *guard =
-      entry_guard_get_by_id_digest(circ->_base.n_conn->identity_digest);
+    tor_assert(!(circ->_base.n_chan->is_listener));
+    guard =
+      entry_guard_get_by_id_digest(circ->_base.n_chan->
+                                     u.cell_chan.identity_digest);
 
     if (guard) {
       if (circ->path_state == PATH_STATE_DID_FIRST_HOP) {
@@ -3021,7 +3059,7 @@ circuit_truncated(origin_circuit_t *circ, crypt_path_t *layer, int reason)
    *     just give up.
    */
   circuit_mark_for_close(TO_CIRCUIT(circ),
-          END_CIRC_REASON_FLAG_REMOTE|reason);
+          END_CIRC_REASON_FLAG_REMOTE|END_CIRC_REASON_CHANNEL_CLOSED|reason);
   return 0;
 
 #if 0
@@ -3095,12 +3133,12 @@ onionskin_answer(or_circuit_t *circ, uint8_t cell_type, const char *payload,
   circ->is_first_hop = (cell_type == CELL_CREATED_FAST);
 
   append_cell_to_circuit_queue(TO_CIRCUIT(circ),
-                               circ->p_conn, &cell, CELL_DIRECTION_IN, 0);
+                               circ->p_chan, &cell, CELL_DIRECTION_IN, 0);
   log_debug(LD_CIRC,"Finished sending '%s' cell.",
             circ->is_first_hop ? "created_fast" : "created");
 
-  if (!is_local_addr(&circ->p_conn->_base.addr) &&
-      !connection_or_nonopen_was_started_here(circ->p_conn)) {
+  if (!channel_is_local(circ->p_chan) &&
+      !channel_is_outgoing(circ->p_chan)) {
     /* record that we could process create cells from a non-local conn
      * that we didn't initiate; presumably this means that create cells
      * can reach us too. */
diff --git a/src/or/circuitbuild.h b/src/or/circuitbuild.h
index 8ec48beb0b..0abffc5166 100644
--- a/src/or/circuitbuild.h
+++ b/src/or/circuitbuild.h
@@ -22,7 +22,7 @@ origin_circuit_t *circuit_establish_circuit(uint8_t purpose,
                                             extend_info_t *exit,
                                             int flags);
 int circuit_handle_first_hop(origin_circuit_t *circ);
-void circuit_n_conn_done(or_connection_t *or_conn, int status);
+void circuit_n_chan_done(channel_t *chan, int status);
 int inform_testing_reachability(void);
 int circuit_timeout_want_to_count_circ(origin_circuit_t *circ);
 int circuit_send_next_onion_skin(origin_circuit_t *circ);
diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c
index d9b74bd4c2..4746f912de 100644
--- a/src/or/circuitlist.c
+++ b/src/or/circuitlist.c
@@ -10,6 +10,7 @@
  **/
 
 #include "or.h"
+#include "channel.h"
 #include "circuitbuild.h"
 #include "circuitlist.h"
 #include "circuituse.h"
@@ -34,8 +35,8 @@
 /** A global list of all circuits at this hop. */
 circuit_t *global_circuitlist=NULL;
 
-/** A list of all the circuits in CIRCUIT_STATE_OR_WAIT. */
-static smartlist_t *circuits_pending_or_conns=NULL;
+/** A list of all the circuits in CIRCUIT_STATE_CHAN_WAIT. */
+static smartlist_t *circuits_pending_chans = NULL;
 
 static void circuit_free(circuit_t *circ);
 static void circuit_free_cpath(crypt_path_t *cpath);
@@ -44,154 +45,156 @@ static void cpath_ref_decref(crypt_path_reference_t *cpath_ref);
 
 /********* END VARIABLES ************/
 
-/** A map from OR connection and circuit ID to circuit.  (Lookup performance is
+/** A map from channel and circuit ID to circuit.  (Lookup performance is
  * very important here, since we need to do it every time a cell arrives.) */
-typedef struct orconn_circid_circuit_map_t {
-  HT_ENTRY(orconn_circid_circuit_map_t) node;
-  or_connection_t *or_conn;
+typedef struct chan_circid_circuit_map_t {
+  HT_ENTRY(chan_circid_circuit_map_t) node;
+  channel_t *chan;
   circid_t circ_id;
   circuit_t *circuit;
-} orconn_circid_circuit_map_t;
+} chan_circid_circuit_map_t;
 
-/** Helper for hash tables: compare the OR connection and circuit ID for a and
+/** Helper for hash tables: compare the channel and circuit ID for a and
  * b, and return less than, equal to, or greater than zero appropriately.
  */
 static INLINE int
-_orconn_circid_entries_eq(orconn_circid_circuit_map_t *a,
-                          orconn_circid_circuit_map_t *b)
+_chan_circid_entries_eq(chan_circid_circuit_map_t *a,
+                        chan_circid_circuit_map_t *b)
 {
-  return a->or_conn == b->or_conn && a->circ_id == b->circ_id;
+  return a->chan == b->chan && a->circ_id == b->circ_id;
 }
 
 /** Helper: return a hash based on circuit ID and the pointer value of
- * or_conn in <b>a</b>. */
+ * chan in <b>a</b>. */
 static INLINE unsigned int
-_orconn_circid_entry_hash(orconn_circid_circuit_map_t *a)
+_chan_circid_entry_hash(chan_circid_circuit_map_t *a)
 {
-  return (((unsigned)a->circ_id)<<8) ^ (unsigned)(uintptr_t)(a->or_conn);
+  return (((unsigned)a->circ_id)<<8) ^ (unsigned)(uintptr_t)(a->chan);
 }
 
-/** Map from [orconn,circid] to circuit. */
-static HT_HEAD(orconn_circid_map, orconn_circid_circuit_map_t)
-     orconn_circid_circuit_map = HT_INITIALIZER();
-HT_PROTOTYPE(orconn_circid_map, orconn_circid_circuit_map_t, node,
-             _orconn_circid_entry_hash, _orconn_circid_entries_eq)
-HT_GENERATE(orconn_circid_map, orconn_circid_circuit_map_t, node,
-            _orconn_circid_entry_hash, _orconn_circid_entries_eq, 0.6,
+/** Map from [chan,circid] to circuit. */
+static HT_HEAD(chan_circid_map, chan_circid_circuit_map_t)
+     chan_circid_map = HT_INITIALIZER();
+HT_PROTOTYPE(chan_circid_map, chan_circid_circuit_map_t, node,
+             _chan_circid_entry_hash, _chan_circid_entries_eq)
+HT_GENERATE(chan_circid_map, chan_circid_circuit_map_t, node,
+            _chan_circid_entry_hash, _chan_circid_entries_eq, 0.6,
             malloc, realloc, free)
 
-/** The most recently returned entry from circuit_get_by_circid_orconn;
+/** The most recently returned entry from circuit_get_by_circid_chan;
  * used to improve performance when many cells arrive in a row from the
  * same circuit.
  */
-orconn_circid_circuit_map_t *_last_circid_orconn_ent = NULL;
+chan_circid_circuit_map_t *_last_circid_chan_ent = NULL;
 
-/** Implementation helper for circuit_set_{p,n}_circid_orconn: A circuit ID
- * and/or or_connection for circ has just changed from <b>old_conn, old_id</b>
- * to <b>conn, id</b>.  Adjust the conn,circid map as appropriate, removing
+/** Implementation helper for circuit_set_{p,n}_circid_channel: A circuit ID
+ * and/or channel for circ has just changed from <b>old_chan, old_id</b>
+ * to <b>chan, id</b>.  Adjust the chan,circid map as appropriate, removing
  * the old entry (if any) and adding a new one. */
 static void
-circuit_set_circid_orconn_helper(circuit_t *circ, int direction,
-                                 circid_t id,
-                                 or_connection_t *conn)
+circuit_set_circid_chan_helper(circuit_t *circ, int direction,
+                               circid_t id,
+                               channel_t *chan)
 {
-  orconn_circid_circuit_map_t search;
-  orconn_circid_circuit_map_t *found;
-  or_connection_t *old_conn, **conn_ptr;
+  chan_circid_circuit_map_t search;
+  chan_circid_circuit_map_t *found;
+  channel_t *old_chan, **chan_ptr;
   circid_t old_id, *circid_ptr;
   int was_active, make_active;
 
+  if (chan) tor_assert(!(chan->is_listener));
+
   if (direction == CELL_DIRECTION_OUT) {
-    conn_ptr = &circ->n_conn;
+    chan_ptr = &circ->n_chan;
     circid_ptr = &circ->n_circ_id;
-    was_active = circ->next_active_on_n_conn != NULL;
-    make_active = circ->n_conn_cells.n > 0;
+    was_active = circ->next_active_on_n_chan != NULL;
+    make_active = circ->n_chan_cells.n > 0;
   } else {
     or_circuit_t *c = TO_OR_CIRCUIT(circ);
-    conn_ptr = &c->p_conn;
+    chan_ptr = &c->p_chan;
     circid_ptr = &c->p_circ_id;
-    was_active = c->next_active_on_p_conn != NULL;
-    make_active = c->p_conn_cells.n > 0;
+    was_active = c->next_active_on_p_chan != NULL;
+    make_active = c->p_chan_cells.n > 0;
   }
-  old_conn = *conn_ptr;
+  old_chan = *chan_ptr;
   old_id = *circid_ptr;
 
-  if (id == old_id && conn == old_conn)
+  if (id == old_id && chan == old_chan)
     return;
 
-  if (_last_circid_orconn_ent &&
-      ((old_id == _last_circid_orconn_ent->circ_id &&
-        old_conn == _last_circid_orconn_ent->or_conn) ||
-       (id == _last_circid_orconn_ent->circ_id &&
-        conn == _last_circid_orconn_ent->or_conn))) {
-    _last_circid_orconn_ent = NULL;
+  if (_last_circid_chan_ent &&
+      ((old_id == _last_circid_chan_ent->circ_id &&
+        old_chan == _last_circid_chan_ent->chan) ||
+       (id == _last_circid_chan_ent->circ_id &&
+        chan == _last_circid_chan_ent->chan))) {
+    _last_circid_chan_ent = NULL;
   }
 
-  if (old_conn) { /* we may need to remove it from the conn-circid map */
-    tor_assert(old_conn->_base.magic == OR_CONNECTION_MAGIC);
+  if (old_chan) { /* we may need to remove it from the conn-circid map */
+    tor_assert(!(old_chan->is_listener));
     search.circ_id = old_id;
-    search.or_conn = old_conn;
-    found = HT_REMOVE(orconn_circid_map, &orconn_circid_circuit_map, &search);
+    search.chan = old_chan;
+    found = HT_REMOVE(chan_circid_map, &chan_circid_map, &search);
     if (found) {
       tor_free(found);
-      --old_conn->n_circuits;
+      --old_chan->u.cell_chan.n_circuits;
     }
-    if (was_active && old_conn != conn)
-      make_circuit_inactive_on_conn(circ,old_conn);
+    if (was_active && old_chan != chan)
+      make_circuit_inactive_on_chan(circ, old_chan);
   }
 
   /* Change the values only after we have possibly made the circuit inactive
-   * on the previous conn. */
-  *conn_ptr = conn;
+   * on the previous chan. */
+  *chan_ptr = chan;
   *circid_ptr = id;
 
-  if (conn == NULL)
+  if (chan == NULL)
     return;
 
   /* now add the new one to the conn-circid map */
   search.circ_id = id;
-  search.or_conn = conn;
-  found = HT_FIND(orconn_circid_map, &orconn_circid_circuit_map, &search);
+  search.chan = chan;
+  found = HT_FIND(chan_circid_map, &chan_circid_map, &search);
   if (found) {
     found->circuit = circ;
   } else {
-    found = tor_malloc_zero(sizeof(orconn_circid_circuit_map_t));
+    found = tor_malloc_zero(sizeof(chan_circid_circuit_map_t));
     found->circ_id = id;
-    found->or_conn = conn;
+    found->chan = chan;
     found->circuit = circ;
-    HT_INSERT(orconn_circid_map, &orconn_circid_circuit_map, found);
+    HT_INSERT(chan_circid_map, &chan_circid_map, found);
   }
-  if (make_active && old_conn != conn)
-    make_circuit_active_on_conn(circ,conn);
+  if (make_active && old_chan != chan)
+    make_circuit_active_on_chan(circ,chan);
 
-  ++conn->n_circuits;
+  ++chan->u.cell_chan.n_circuits;
 }
 
 /** Set the p_conn field of a circuit <b>circ</b>, along
  * with the corresponding circuit ID, and add the circuit as appropriate
- * to the (orconn,id)-\>circuit map. */
+ * to the (chan,id)-\>circuit map. */
 void
-circuit_set_p_circid_orconn(or_circuit_t *circ, circid_t id,
-                            or_connection_t *conn)
+circuit_set_p_circid_chan(or_circuit_t *circ, circid_t id,
+                          channel_t *chan)
 {
-  circuit_set_circid_orconn_helper(TO_CIRCUIT(circ), CELL_DIRECTION_IN,
-                                   id, conn);
+  circuit_set_circid_chan_helper(TO_CIRCUIT(circ), CELL_DIRECTION_IN,
+                                 id, chan);
 
-  if (conn)
-    tor_assert(bool_eq(circ->p_conn_cells.n, circ->next_active_on_p_conn));
+  if (chan)
+    tor_assert(bool_eq(circ->p_chan_cells.n, circ->next_active_on_p_chan));
 }
 
 /** Set the n_conn field of a circuit <b>circ</b>, along
  * with the corresponding circuit ID, and add the circuit as appropriate
- * to the (orconn,id)-\>circuit map. */
+ * to the (chan,id)-\>circuit map. */
 void
-circuit_set_n_circid_orconn(circuit_t *circ, circid_t id,
-                            or_connection_t *conn)
+circuit_set_n_circid_chan(circuit_t *circ, circid_t id,
+                          channel_t *chan)
 {
-  circuit_set_circid_orconn_helper(circ, CELL_DIRECTION_OUT, id, conn);
+  circuit_set_circid_chan_helper(circ, CELL_DIRECTION_OUT, id, chan);
 
-  if (conn)
-    tor_assert(bool_eq(circ->n_conn_cells.n, circ->next_active_on_n_conn));
+  if (chan)
+    tor_assert(bool_eq(circ->n_chan_cells.n, circ->next_active_on_n_chan));
 }
 
 /** Change the state of <b>circ</b> to <b>state</b>, adding it to or removing
@@ -202,18 +205,18 @@ circuit_set_state(circuit_t *circ, uint8_t state)
   tor_assert(circ);
   if (state == circ->state)
     return;
-  if (!circuits_pending_or_conns)
-    circuits_pending_or_conns = smartlist_new();
-  if (circ->state == CIRCUIT_STATE_OR_WAIT) {
+  if (!circuits_pending_chans)
+    circuits_pending_chans = smartlist_new();
+  if (circ->state == CIRCUIT_STATE_CHAN_WAIT) {
     /* remove from waiting-circuit list. */
-    smartlist_remove(circuits_pending_or_conns, circ);
+    smartlist_remove(circuits_pending_chans, circ);
   }
-  if (state == CIRCUIT_STATE_OR_WAIT) {
+  if (state == CIRCUIT_STATE_CHAN_WAIT) {
     /* add to waiting-circuit list. */
-    smartlist_add(circuits_pending_or_conns, circ);
+    smartlist_add(circuits_pending_chans, circ);
   }
   if (state == CIRCUIT_STATE_OPEN)
-    tor_assert(!circ->n_conn_onionskin);
+    tor_assert(!circ->n_chan_onionskin);
   circ->state = state;
 }
 
@@ -232,31 +235,31 @@ circuit_add(circuit_t *circ)
   }
 }
 
-/** Append to <b>out</b> all circuits in state OR_WAIT waiting for
+/** Append to <b>out</b> all circuits in state CHAN_WAIT waiting for
  * the given connection. */
 void
-circuit_get_all_pending_on_or_conn(smartlist_t *out, or_connection_t *or_conn)
+circuit_get_all_pending_on_channel(smartlist_t *out, channel_t *chan)
 {
   tor_assert(out);
-  tor_assert(or_conn);
+  tor_assert(chan);
+  tor_assert(!(chan->is_listener));
 
-  if (!circuits_pending_or_conns)
+  if (!circuits_pending_chans)
     return;
 
-  SMARTLIST_FOREACH_BEGIN(circuits_pending_or_conns, circuit_t *, circ) {
+  SMARTLIST_FOREACH_BEGIN(circuits_pending_chans, circuit_t *, circ) {
     if (circ->marked_for_close)
       continue;
     if (!circ->n_hop)
       continue;
-    tor_assert(circ->state == CIRCUIT_STATE_OR_WAIT);
+    tor_assert(circ->state == CIRCUIT_STATE_CHAN_WAIT);
     if (tor_digest_is_zero(circ->n_hop->identity_digest)) {
       /* Look at addr/port. This is an unkeyed connection. */
-      if (!tor_addr_eq(&circ->n_hop->addr, &or_conn->_base.addr) ||
-          circ->n_hop->port != or_conn->_base.port)
+      if (!channel_matches_extend_info(chan, circ->n_hop))
         continue;
     } else {
       /* We expected a key. See if it's the right one. */
-      if (tor_memneq(or_conn->identity_digest,
+      if (tor_memneq(chan->u.cell_chan.identity_digest,
                  circ->n_hop->identity_digest, DIGEST_LEN))
         continue;
     }
@@ -264,19 +267,24 @@ circuit_get_all_pending_on_or_conn(smartlist_t *out, or_connection_t *or_conn)
   } SMARTLIST_FOREACH_END(circ);
 }
 
-/** Return the number of circuits in state OR_WAIT, waiting for the given
- * connection. */
+/** Return the number of circuits in state CHAN_WAIT, waiting for the given
+ * channel. */
 int
-circuit_count_pending_on_or_conn(or_connection_t *or_conn)
+circuit_count_pending_on_channel(channel_t *chan)
 {
   int cnt;
   smartlist_t *sl = smartlist_new();
-  circuit_get_all_pending_on_or_conn(sl, or_conn);
+
+  tor_assert(chan);
+  tor_assert(!(chan->is_listener));
+
+  circuit_get_all_pending_on_channel(sl, chan);
   cnt = smartlist_len(sl);
   smartlist_free(sl);
   log_debug(LD_CIRC,"or_conn to %s at %s, %d pending circs",
-            or_conn->nickname ? or_conn->nickname : "NULL",
-            or_conn->_base.address,
+            chan->u.cell_chan.nickname ?
+              chan->u.cell_chan.nickname : "NULL",
+            channel_get_canonical_remote_descr(chan),
             cnt);
   return cnt;
 }
@@ -324,7 +332,7 @@ circuit_state_to_string(int state)
   switch (state) {
     case CIRCUIT_STATE_BUILDING: return "doing handshakes";
     case CIRCUIT_STATE_ONIONSKIN_PENDING: return "processing the onion";
-    case CIRCUIT_STATE_OR_WAIT: return "connecting to server";
+    case CIRCUIT_STATE_CHAN_WAIT: return "connecting to server";
     case CIRCUIT_STATE_OPEN: return "open";
     default:
       log_warn(LD_BUG, "Unknown circuit state %d", state);
@@ -522,7 +530,7 @@ init_circuit_base(circuit_t *circ)
   circ->n_cell_ewma.last_adjusted_tick = cell_ewma_get_tick();
   circ->n_cell_ewma.cell_count = 0.0;
   circ->n_cell_ewma.heap_index = -1;
-  circ->n_cell_ewma.is_for_p_conn = 0;
+  circ->n_cell_ewma.is_for_p_chan = 0;
 
   circuit_add(circ);
 }
@@ -556,7 +564,7 @@ origin_circuit_new(void)
 /** Allocate a new or_circuit_t, connected to <b>p_conn</b> as
  * <b>p_circ_id</b>.  If <b>p_conn</b> is NULL, the circuit is unattached. */
 or_circuit_t *
-or_circuit_new(circid_t p_circ_id, or_connection_t *p_conn)
+or_circuit_new(circid_t p_circ_id, channel_t *p_chan)
 {
   /* CircIDs */
   or_circuit_t *circ;
@@ -564,8 +572,8 @@ or_circuit_new(circid_t p_circ_id, or_connection_t *p_conn)
   circ = tor_malloc_zero(sizeof(or_circuit_t));
   circ->_base.magic = OR_CIRCUIT_MAGIC;
 
-  if (p_conn)
-    circuit_set_p_circid_orconn(circ, p_circ_id, p_conn);
+  if (p_chan)
+    circuit_set_p_circid_chan(circ, p_circ_id, p_chan);
 
   circ->remaining_relay_early_cells = MAX_RELAY_EARLY_CELLS_PER_CIRCUIT;
 
@@ -576,7 +584,7 @@ or_circuit_new(circid_t p_circ_id, or_connection_t *p_conn)
   /* Initialize the cell counts to 0 */
   circ->p_cell_ewma.cell_count = 0.0;
   circ->p_cell_ewma.last_adjusted_tick = cell_ewma_get_tick();
-  circ->p_cell_ewma.is_for_p_conn = 1;
+  circ->p_cell_ewma.is_for_p_chan = 1;
 
   /* It's not in any heap yet. */
   circ->p_cell_ewma.heap_index = -1;
@@ -641,22 +649,22 @@ circuit_free(circuit_t *circ)
     }
 
     /* remove from map. */
-    circuit_set_p_circid_orconn(ocirc, 0, NULL);
+    circuit_set_p_circid_chan(ocirc, 0, NULL);
 
     /* Clear cell queue _after_ removing it from the map.  Otherwise our
      * "active" checks will be violated. */
-    cell_queue_clear(&ocirc->p_conn_cells);
+    cell_queue_clear(&ocirc->p_chan_cells);
   }
 
   extend_info_free(circ->n_hop);
-  tor_free(circ->n_conn_onionskin);
+  tor_free(circ->n_chan_onionskin);
 
   /* Remove from map. */
-  circuit_set_n_circid_orconn(circ, 0, NULL);
+  circuit_set_n_circid_chan(circ, 0, NULL);
 
   /* Clear cell queue _after_ removing it from the map.  Otherwise our
    * "active" checks will be violated. */
-  cell_queue_clear(&circ->n_conn_cells);
+  cell_queue_clear(&circ->n_chan_cells);
 
   memset(mem, 0xAA, memlen); /* poison memory */
   tor_free(mem);
@@ -702,10 +710,10 @@ circuit_free_all(void)
     global_circuitlist = next;
   }
 
-  smartlist_free(circuits_pending_or_conns);
-  circuits_pending_or_conns = NULL;
+  smartlist_free(circuits_pending_chans);
+  circuits_pending_chans = NULL;
 
-  HT_CLEAR(orconn_circid_map, &orconn_circid_circuit_map);
+  HT_CLEAR(chan_circid_map, &chan_circid_map);
 }
 
 /** Deallocate space associated with the cpath node <b>victim</b>. */
@@ -742,8 +750,12 @@ cpath_ref_decref(crypt_path_reference_t *cpath_ref)
  * of information about circuit <b>circ</b>.
  */
 static void
-circuit_dump_details(int severity, circuit_t *circ, int conn_array_index,
-                     const char *type, int this_circid, int other_circid)
+circuit_dump_conn_details(int severity,
+                          circuit_t *circ,
+                          int conn_array_index,
+                          const char *type,
+                          int this_circid,
+                          int other_circid)
 {
   log(severity, LD_CIRC, "Conn %d has %s circuit: circID %d (other side %d), "
       "state %d (%s), born %ld:",
@@ -764,50 +776,102 @@ circuit_dump_by_conn(connection_t *conn, int severity)
   circuit_t *circ;
   edge_connection_t *tmpconn;
 
-  for (circ=global_circuitlist;circ;circ = circ->next) {
+  for (circ = global_circuitlist; circ; circ = circ->next) {
     circid_t n_circ_id = circ->n_circ_id, p_circ_id = 0;
-    if (circ->marked_for_close)
+
+    if (circ->marked_for_close) {
       continue;
+    }
 
-    if (! CIRCUIT_IS_ORIGIN(circ))
+    if (!CIRCUIT_IS_ORIGIN(circ)) {
       p_circ_id = TO_OR_CIRCUIT(circ)->p_circ_id;
+    }
 
-    if (! CIRCUIT_IS_ORIGIN(circ) && TO_OR_CIRCUIT(circ)->p_conn &&
-        TO_CONN(TO_OR_CIRCUIT(circ)->p_conn) == conn)
-      circuit_dump_details(severity, circ, conn->conn_array_index, "App-ward",
-                           p_circ_id, n_circ_id);
     if (CIRCUIT_IS_ORIGIN(circ)) {
       for (tmpconn=TO_ORIGIN_CIRCUIT(circ)->p_streams; tmpconn;
            tmpconn=tmpconn->next_stream) {
         if (TO_CONN(tmpconn) == conn) {
-          circuit_dump_details(severity, circ, conn->conn_array_index,
-                               "App-ward", p_circ_id, n_circ_id);
+          circuit_dump_conn_details(severity, circ, conn->conn_array_index,
+                                    "App-ward", p_circ_id, n_circ_id);
         }
       }
     }
-    if (circ->n_conn && TO_CONN(circ->n_conn) == conn)
-      circuit_dump_details(severity, circ, conn->conn_array_index, "Exit-ward",
-                           n_circ_id, p_circ_id);
+
     if (! CIRCUIT_IS_ORIGIN(circ)) {
       for (tmpconn=TO_OR_CIRCUIT(circ)->n_streams; tmpconn;
            tmpconn=tmpconn->next_stream) {
         if (TO_CONN(tmpconn) == conn) {
-          circuit_dump_details(severity, circ, conn->conn_array_index,
-                               "Exit-ward", n_circ_id, p_circ_id);
+          circuit_dump_conn_details(severity, circ, conn->conn_array_index,
+                                    "Exit-ward", n_circ_id, p_circ_id);
         }
       }
     }
-    if (!circ->n_conn && circ->n_hop &&
-        tor_addr_eq(&circ->n_hop->addr, &conn->addr) &&
-        circ->n_hop->port == conn->port &&
-        conn->type == CONN_TYPE_OR &&
-        tor_memeq(TO_OR_CONN(conn)->identity_digest,
-                circ->n_hop->identity_digest, DIGEST_LEN)) {
-      circuit_dump_details(severity, circ, conn->conn_array_index,
-                           (circ->state == CIRCUIT_STATE_OPEN &&
-                            !CIRCUIT_IS_ORIGIN(circ)) ?
-                             "Endpoint" : "Pending",
-                           n_circ_id, p_circ_id);
+  }
+}
+
+/** A helper function for circuit_dump_by_chan() below. Log a bunch
+ * of information about circuit <b>circ</b>.
+ */
+static void
+circuit_dump_chan_details(int severity,
+                          circuit_t *circ,
+                          channel_t *chan,
+                          const char *type,
+                          int this_circid,
+                          int other_circid)
+{
+  log(severity, LD_CIRC, "Conn %p has %s circuit: circID %d (other side %d), "
+      "state %d (%s), born %ld:",
+      chan, type, this_circid, other_circid, circ->state,
+      circuit_state_to_string(circ->state),
+      (long)circ->timestamp_created.tv_sec);
+  if (CIRCUIT_IS_ORIGIN(circ)) { /* circ starts at this node */
+    circuit_log_path(severity, LD_CIRC, TO_ORIGIN_CIRCUIT(circ));
+  }
+}
+
+/** Log, at severity <b>severity</b>, information about each circuit
+ * that is connected to <b>chan</b>.
+ */
+void
+circuit_dump_by_chan(channel_t *chan, int severity)
+{
+  circuit_t *circ;
+
+  tor_assert(chan);
+  tor_assert(!(chan->is_listener));
+
+  for (circ = global_circuitlist; circ; circ = circ->next) {
+    circid_t n_circ_id = circ->n_circ_id, p_circ_id = 0;
+
+    if (circ->marked_for_close) {
+      continue;
+    }
+
+    if (!CIRCUIT_IS_ORIGIN(circ)) {
+      p_circ_id = TO_OR_CIRCUIT(circ)->p_circ_id;
+    }
+
+    if (! CIRCUIT_IS_ORIGIN(circ) && TO_OR_CIRCUIT(circ)->p_chan &&
+        TO_OR_CIRCUIT(circ)->p_chan == chan) {
+      circuit_dump_chan_details(severity, circ, chan, "App-ward",
+                                p_circ_id, n_circ_id);
+    }
+
+    if (circ->n_chan && circ->n_chan == chan) {
+      circuit_dump_chan_details(severity, circ, chan, "Exit-ward",
+                                n_circ_id, p_circ_id);
+    }
+
+    if (!circ->n_chan && circ->n_hop &&
+        channel_matches_extend_info(chan, circ->n_hop) &&
+        tor_memeq(chan->u.cell_chan.identity_digest,
+                  circ->n_hop->identity_digest, DIGEST_LEN)) {
+      circuit_dump_chan_details(severity, circ, chan,
+                                (circ->state == CIRCUIT_STATE_OPEN &&
+                                 !CIRCUIT_IS_ORIGIN(circ)) ?
+                                "Endpoint" : "Pending",
+                                n_circ_id, p_circ_id);
     }
   }
 }
@@ -832,27 +896,37 @@ circuit_get_by_global_id(uint32_t id)
 
 /** Return a circ such that:
  *  - circ-\>n_circ_id or circ-\>p_circ_id is equal to <b>circ_id</b>, and
- *  - circ is attached to <b>conn</b>, either as p_conn or n_conn.
+ *  - circ is attached to <b>chan</b>, either as p_chan or n_chan.
  * Return NULL if no such circuit exists.
  */
 static INLINE circuit_t *
-circuit_get_by_circid_orconn_impl(circid_t circ_id, or_connection_t *conn)
+circuit_get_by_circid_channel_impl(circid_t circ_id, channel_t *chan)
 {
-  orconn_circid_circuit_map_t search;
-  orconn_circid_circuit_map_t *found;
+  chan_circid_circuit_map_t search;
+  chan_circid_circuit_map_t *found;
 
-  if (_last_circid_orconn_ent &&
-      circ_id == _last_circid_orconn_ent->circ_id &&
-      conn == _last_circid_orconn_ent->or_conn) {
-    found = _last_circid_orconn_ent;
+  if (_last_circid_chan_ent &&
+      circ_id == _last_circid_chan_ent->circ_id &&
+      chan == _last_circid_chan_ent->chan) {
+    found = _last_circid_chan_ent;
   } else {
     search.circ_id = circ_id;
-    search.or_conn = conn;
-    found = HT_FIND(orconn_circid_map, &orconn_circid_circuit_map, &search);
-    _last_circid_orconn_ent = found;
+    search.chan = chan;
+    found = HT_FIND(chan_circid_map, &chan_circid_map, &search);
+    _last_circid_chan_ent = found;
   }
-  if (found && found->circuit)
+  if (found && found->circuit) {
+    log_debug(LD_CIRC,
+              "circuit_get_by_circid_channel_impl() returning circuit %p for"
+              " circ_id %d, channel ID %lu (%p)",
+              found->circuit, circ_id, chan->global_identifier, chan);
     return found->circuit;
+  }
+
+  log_debug(LD_CIRC,
+            "circuit_get_by_circid_channel_impl() found nothing for"
+            " circ_id %d, channel ID %lu (%p)",
+            circ_id, chan->global_identifier, chan);
 
   return NULL;
   /* The rest of this checks for bugs. Disabled by default. */
@@ -862,15 +936,15 @@ circuit_get_by_circid_orconn_impl(circid_t circ_id, or_connection_t *conn)
     for (circ=global_circuitlist;circ;circ = circ->next) {
       if (! CIRCUIT_IS_ORIGIN(circ)) {
         or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
-        if (or_circ->p_conn == conn && or_circ->p_circ_id == circ_id) {
+        if (or_circ->p_chan == chan && or_circ->p_circ_id == circ_id) {
           log_warn(LD_BUG,
-                   "circuit matches p_conn, but not in hash table (Bug!)");
+                   "circuit matches p_chan, but not in hash table (Bug!)");
           return circ;
         }
       }
-      if (circ->n_conn == conn && circ->n_circ_id == circ_id) {
+      if (circ->n_chan == chan && circ->n_circ_id == circ_id) {
         log_warn(LD_BUG,
-                 "circuit matches n_conn, but not in hash table (Bug!)");
+                 "circuit matches n_chan, but not in hash table (Bug!)");
         return circ;
       }
     }
@@ -880,14 +954,14 @@ circuit_get_by_circid_orconn_impl(circid_t circ_id, or_connection_t *conn)
 
 /** Return a circ such that:
  *  - circ-\>n_circ_id or circ-\>p_circ_id is equal to <b>circ_id</b>, and
- *  - circ is attached to <b>conn</b>, either as p_conn or n_conn.
+ *  - circ is attached to <b>chan</b>, either as p_chan or n_chan.
  *  - circ is not marked for close.
  * Return NULL if no such circuit exists.
  */
 circuit_t *
-circuit_get_by_circid_orconn(circid_t circ_id, or_connection_t *conn)
+circuit_get_by_circid_channel(circid_t circ_id, channel_t *chan)
 {
-  circuit_t *circ = circuit_get_by_circid_orconn_impl(circ_id, conn);
+  circuit_t *circ = circuit_get_by_circid_channel_impl(circ_id, chan);
   if (!circ || circ->marked_for_close)
     return NULL;
   else
@@ -895,11 +969,11 @@ circuit_get_by_circid_orconn(circid_t circ_id, or_connection_t *conn)
 }
 
 /** Return true iff the circuit ID <b>circ_id</b> is currently used by a
- * circuit, marked or not, on <b>conn</b>. */
+ * circuit, marked or not, on <b>chan</b>. */
 int
-circuit_id_in_use_on_orconn(circid_t circ_id, or_connection_t *conn)
+circuit_id_in_use_on_channel(circid_t circ_id, channel_t *chan)
 {
-  return circuit_get_by_circid_orconn_impl(circ_id, conn) != NULL;
+  return circuit_get_by_circid_channel_impl(circ_id, chan) != NULL;
 }
 
 /** Return the circuit that a given edge connection is using. */
@@ -916,27 +990,27 @@ circuit_get_by_edge_conn(edge_connection_t *conn)
   return circ;
 }
 
-/** For each circuit that has <b>conn</b> as n_conn or p_conn, unlink the
- * circuit from the orconn,circid map, and mark it for close if it hasn't
+/** For each circuit that has <b>chan</b> as n_chan or p_chan, unlink the
+ * circuit from the chan,circid map, and mark it for close if it hasn't
  * been marked already.
  */
 void
-circuit_unlink_all_from_or_conn(or_connection_t *conn, int reason)
+circuit_unlink_all_from_channel(channel_t *chan, int reason)
 {
   circuit_t *circ;
 
-  connection_or_unlink_all_active_circs(conn);
+  channel_unlink_all_active_circs(chan);
 
   for (circ = global_circuitlist; circ; circ = circ->next) {
     int mark = 0;
-    if (circ->n_conn == conn) {
-        circuit_set_n_circid_orconn(circ, 0, NULL);
+    if (circ->n_chan == chan) {
+        circuit_set_n_circid_chan(circ, 0, NULL);
         mark = 1;
     }
     if (! CIRCUIT_IS_ORIGIN(circ)) {
       or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
-      if (or_circ->p_conn == conn) {
-        circuit_set_p_circid_orconn(or_circ, 0, NULL);
+      if (or_circ->p_chan == chan) {
+        circuit_set_p_circid_chan(or_circ, 0, NULL);
         mark = 1;
       }
     }
@@ -1267,9 +1341,9 @@ _circuit_mark_for_close(circuit_t *circ, int reason, int line,
       circuit_rep_hist_note_result(ocirc);
     }
   }
-  if (circ->state == CIRCUIT_STATE_OR_WAIT) {
-    if (circuits_pending_or_conns)
-      smartlist_remove(circuits_pending_or_conns, circ);
+  if (circ->state == CIRCUIT_STATE_CHAN_WAIT) {
+    if (circuits_pending_chans)
+      smartlist_remove(circuits_pending_chans, circ);
   }
   if (CIRCUIT_IS_ORIGIN(circ)) {
     control_event_circuit_status(TO_ORIGIN_CIRCUIT(circ),
@@ -1306,9 +1380,9 @@ _circuit_mark_for_close(circuit_t *circ, int reason, int line,
                                              INTRO_POINT_FAILURE_UNREACHABLE);
     }
   }
-  if (circ->n_conn) {
-    circuit_clear_cell_queue(circ, circ->n_conn);
-    connection_or_send_destroy(circ->n_circ_id, circ->n_conn, reason);
+  if (circ->n_chan) {
+    circuit_clear_cell_queue(circ, circ->n_chan);
+    channel_send_destroy(circ->n_circ_id, circ->n_chan, reason);
   }
 
   if (! CIRCUIT_IS_ORIGIN(circ)) {
@@ -1333,9 +1407,9 @@ _circuit_mark_for_close(circuit_t *circ, int reason, int line,
       conn->on_circuit = NULL;
     }
 
-    if (or_circ->p_conn) {
-      circuit_clear_cell_queue(circ, or_circ->p_conn);
-      connection_or_send_destroy(or_circ->p_circ_id, or_circ->p_conn, reason);
+    if (or_circ->p_chan) {
+      circuit_clear_cell_queue(circ, or_circ->p_chan);
+      channel_send_destroy(or_circ->p_circ_id, or_circ->p_chan, reason);
     }
   } else {
     origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
@@ -1438,22 +1512,22 @@ assert_circuit_ok(const circuit_t *c)
       or_circ = TO_OR_CIRCUIT(nonconst_circ);
   }
 
-  if (c->n_conn) {
+  if (c->n_chan) {
     tor_assert(!c->n_hop);
 
     if (c->n_circ_id) {
       /* We use the _impl variant here to make sure we don't fail on marked
        * circuits, which would not be returned by the regular function. */
-      circuit_t *c2 = circuit_get_by_circid_orconn_impl(c->n_circ_id,
-                                                        c->n_conn);
+      circuit_t *c2 = circuit_get_by_circid_channel_impl(c->n_circ_id,
+                                                         c->n_chan);
       tor_assert(c == c2);
     }
   }
-  if (or_circ && or_circ->p_conn) {
+  if (or_circ && or_circ->p_chan) {
     if (or_circ->p_circ_id) {
       /* ibid */
-      circuit_t *c2 = circuit_get_by_circid_orconn_impl(or_circ->p_circ_id,
-                                                        or_circ->p_conn);
+      circuit_t *c2 = circuit_get_by_circid_channel_impl(or_circ->p_circ_id,
+                                                         or_circ->p_chan);
       tor_assert(c == c2);
     }
   }
@@ -1464,7 +1538,7 @@ assert_circuit_ok(const circuit_t *c)
   tor_assert(c->deliver_window >= 0);
   tor_assert(c->package_window >= 0);
   if (c->state == CIRCUIT_STATE_OPEN) {
-    tor_assert(!c->n_conn_onionskin);
+    tor_assert(!c->n_chan_onionskin);
     if (or_circ) {
       tor_assert(or_circ->n_crypto);
       tor_assert(or_circ->p_crypto);
@@ -1472,12 +1546,12 @@ assert_circuit_ok(const circuit_t *c)
       tor_assert(or_circ->p_digest);
     }
   }
-  if (c->state == CIRCUIT_STATE_OR_WAIT && !c->marked_for_close) {
-    tor_assert(circuits_pending_or_conns &&
-               smartlist_isin(circuits_pending_or_conns, c));
+  if (c->state == CIRCUIT_STATE_CHAN_WAIT && !c->marked_for_close) {
+    tor_assert(circuits_pending_chans &&
+               smartlist_isin(circuits_pending_chans, c));
   } else {
-    tor_assert(!circuits_pending_or_conns ||
-               !smartlist_isin(circuits_pending_or_conns, c));
+    tor_assert(!circuits_pending_chans ||
+               !smartlist_isin(circuits_pending_chans, c));
   }
   if (origin_circ && origin_circ->cpath) {
     assert_cpath_ok(origin_circ->cpath);
diff --git a/src/or/circuitlist.h b/src/or/circuitlist.h
index 6e7735476b..f0f4b2a6df 100644
--- a/src/or/circuitlist.h
+++ b/src/or/circuitlist.h
@@ -18,20 +18,21 @@ const char *circuit_purpose_to_controller_string(uint8_t purpose);
 const char *circuit_purpose_to_controller_hs_state_string(uint8_t purpose);
 const char *circuit_purpose_to_string(uint8_t purpose);
 void circuit_dump_by_conn(connection_t *conn, int severity);
-void circuit_set_p_circid_orconn(or_circuit_t *circ, circid_t id,
-                                 or_connection_t *conn);
-void circuit_set_n_circid_orconn(circuit_t *circ, circid_t id,
-                                 or_connection_t *conn);
+void circuit_dump_by_chan(channel_t *chan, int severity);
+void circuit_set_p_circid_chan(or_circuit_t *circ, circid_t id,
+                               channel_t *chan);
+void circuit_set_n_circid_chan(circuit_t *circ, circid_t id,
+                               channel_t *chan);
 void circuit_set_state(circuit_t *circ, uint8_t state);
 void circuit_close_all_marked(void);
 int32_t circuit_initial_package_window(void);
 origin_circuit_t *origin_circuit_new(void);
-or_circuit_t *or_circuit_new(circid_t p_circ_id, or_connection_t *p_conn);
-circuit_t *circuit_get_by_circid_orconn(circid_t circ_id,
-                                        or_connection_t *conn);
-int circuit_id_in_use_on_orconn(circid_t circ_id, or_connection_t *conn);
+or_circuit_t *or_circuit_new(circid_t p_circ_id, channel_t *p_chan);
+circuit_t *circuit_get_by_circid_channel(circid_t circ_id,
+                                         channel_t *chan);
+int circuit_id_in_use_on_channel(circid_t circ_id, channel_t *chan);
 circuit_t *circuit_get_by_edge_conn(edge_connection_t *conn);
-void circuit_unlink_all_from_or_conn(or_connection_t *conn, int reason);
+void circuit_unlink_all_from_channel(channel_t *chan, int reason);
 origin_circuit_t *circuit_get_by_global_id(uint32_t id);
 origin_circuit_t *circuit_get_ready_rend_circ_by_rend_data(
   const rend_data_t *rend_data);
@@ -47,9 +48,9 @@ void _circuit_mark_for_close(circuit_t *circ, int reason,
                              int line, const char *file);
 int circuit_get_cpath_len(origin_circuit_t *circ);
 crypt_path_t *circuit_get_cpath_hop(origin_circuit_t *circ, int hopnum);
-void circuit_get_all_pending_on_or_conn(smartlist_t *out,
-                                        or_connection_t *or_conn);
-int circuit_count_pending_on_or_conn(or_connection_t *or_conn);
+void circuit_get_all_pending_on_channel(smartlist_t *out,
+                                        channel_t *chan);
+int circuit_count_pending_on_channel(channel_t *chan);
 
 #define circuit_mark_for_close(c, reason)                               \
   _circuit_mark_for_close((c), (reason), __LINE__, _SHORT_FILE_)
diff --git a/src/or/circuituse.c b/src/or/circuituse.c
index 79e1ed0fbb..e4e1b8ab63 100644
--- a/src/or/circuituse.c
+++ b/src/or/circuituse.c
@@ -10,6 +10,7 @@
  **/
 
 #include "or.h"
+#include "channel.h"
 #include "circuitbuild.h"
 #include "circuitlist.h"
 #include "circuituse.h"
@@ -53,7 +54,7 @@ circuit_is_acceptable(const origin_circuit_t *origin_circ,
   tor_assert(conn);
   tor_assert(conn->socks_request);
 
-  if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_conn))
+  if (must_be_open && (circ->state != CIRCUIT_STATE_OPEN || !circ->n_chan))
     return 0; /* ignore non-open circs */
   if (circ->marked_for_close)
     return 0;
@@ -565,9 +566,9 @@ circuit_expire_building(void)
       continue;
     }
 
-    if (victim->n_conn)
-      log_info(LD_CIRC,"Abandoning circ %s:%d:%d (state %d:%s, purpose %d)",
-               victim->n_conn->_base.address, victim->n_conn->_base.port,
+    if (victim->n_chan)
+      log_info(LD_CIRC,"Abandoning circ %s:%d (state %d:%s, purpose %d)",
+               channel_get_canonical_remote_descr(victim->n_chan),
                victim->n_circ_id,
                victim->state, circuit_state_to_string(victim->state),
                victim->purpose);
@@ -977,13 +978,13 @@ circuit_expire_old_circuits_serverside(time_t now)
     /* If the circuit has been idle for too long, and there are no streams
      * on it, and it ends here, and it used a create_fast, mark it for close.
      */
-    if (or_circ->is_first_hop && !circ->n_conn &&
+    if (or_circ->is_first_hop && !circ->n_chan &&
         !or_circ->n_streams && !or_circ->resolving_streams &&
-        or_circ->p_conn &&
-        or_circ->p_conn->timestamp_last_added_nonpadding <= cutoff) {
+        or_circ->p_chan &&
+        channel_when_last_xmit(or_circ->p_chan) <= cutoff) {
       log_info(LD_CIRC, "Closing circ_id %d (empty %d secs ago)",
                or_circ->p_circ_id,
-               (int)(now - or_circ->p_conn->timestamp_last_added_nonpadding));
+               (int)(now - channel_when_last_xmit(or_circ->p_chan)));
       circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED);
     }
   }
@@ -1163,6 +1164,7 @@ circuit_try_attaching_streams(origin_circuit_t *circ)
 void
 circuit_build_failed(origin_circuit_t *circ)
 {
+  channel_t *n_chan = NULL;
   /* we should examine circ and see if it failed because of
    * the last hop or an earlier hop. then use this info below.
    */
@@ -1179,11 +1181,13 @@ circuit_build_failed(origin_circuit_t *circ)
     /* We failed at the first hop. If there's an OR connection
      * to blame, blame it. Also, avoid this relay for a while, and
      * fail any one-hop directory fetches destined for it. */
-    const char *n_conn_id = circ->cpath->extend_info->identity_digest;
+    const char *n_chan_id = circ->cpath->extend_info->identity_digest;
     int already_marked = 0;
-    if (circ->_base.n_conn) {
-      or_connection_t *n_conn = circ->_base.n_conn;
-      if (n_conn->is_bad_for_new_circs) {
+    if (circ->_base.n_chan) {
+      n_chan = circ->_base.n_chan;
+      tor_assert(!(n_chan->is_listener));
+
+      if (n_chan->u.cell_chan.is_bad_for_new_circs) {
         /* We only want to blame this router when a fresh healthy
          * connection fails. So don't mark this router as newly failed,
          * since maybe this was just an old circuit attempt that's
@@ -1195,18 +1199,18 @@ circuit_build_failed(origin_circuit_t *circ)
       }
       log_info(LD_OR,
                "Our circuit failed to get a response from the first hop "
-               "(%s:%d). I'm going to try to rotate to a better connection.",
-               n_conn->_base.address, n_conn->_base.port);
-      n_conn->is_bad_for_new_circs = 1;
+               "(%s). I'm going to try to rotate to a better connection.",
+               channel_get_canonical_remote_descr(n_chan));
+      n_chan->u.cell_chan.is_bad_for_new_circs = 1;
     } else {
       log_info(LD_OR,
                "Our circuit died before the first hop with no connection");
     }
-    if (n_conn_id && !already_marked) {
-      entry_guard_register_connect_status(n_conn_id, 0, 1, time(NULL));
+    if (n_chan_id && !already_marked) {
+      entry_guard_register_connect_status(n_chan_id, 0, 1, time(NULL));
       /* if there are any one-hop streams waiting on this circuit, fail
        * them now so they can retry elsewhere. */
-      connection_ap_fail_onehop(n_conn_id, circ->build_state);
+      connection_ap_fail_onehop(n_chan_id, circ->build_state);
     }
   }
 
diff --git a/src/or/main.c b/src/or/main.c
index 74bb696725..a1b1502e4f 100644
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -2148,6 +2148,7 @@ dumpstats(int severity)
         }
       }
     }
+    /* TODO add dump for channels with circuit_dump_by_chan() */
     circuit_dump_by_conn(conn, severity); /* dump info about all the circuits
                                            * using this conn */
   } SMARTLIST_FOREACH_END(conn);
diff --git a/src/or/or.h b/src/or/or.h
index 2eee6ec464..4d2ab21d7d 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -445,9 +445,9 @@ typedef enum {
 #define CIRCUIT_STATE_BUILDING 0
 /** Circuit state: Waiting to process the onionskin. */
 #define CIRCUIT_STATE_ONIONSKIN_PENDING 1
-/** Circuit state: I'd like to deliver a create, but my n_conn is still
+/** Circuit state: I'd like to deliver a create, but my n_chan is still
  * connecting. */
-#define CIRCUIT_STATE_OR_WAIT 2
+#define CIRCUIT_STATE_CHAN_WAIT 2
 /** Circuit state: onionskin(s) processed, ready to send/receive cells. */
 #define CIRCUIT_STATE_OPEN 3
 
@@ -674,7 +674,7 @@ typedef enum {
 #define END_CIRC_REASON_RESOURCELIMIT   5
 #define END_CIRC_REASON_CONNECTFAILED   6
 #define END_CIRC_REASON_OR_IDENTITY     7
-#define END_CIRC_REASON_OR_CONN_CLOSED  8
+#define END_CIRC_REASON_CHANNEL_CLOSED  8
 #define END_CIRC_REASON_FINISHED        9
 #define END_CIRC_REASON_TIMEOUT         10
 #define END_CIRC_REASON_DESTROYED       11
@@ -2590,9 +2590,9 @@ typedef struct circuit_t {
                    * ORIGIN_CIRCUIT_MAGIC or OR_CIRCUIT_MAGIC. */
 
   /** Queue of cells waiting to be transmitted on n_conn. */
-  cell_queue_t n_conn_cells;
-  /** The OR connection that is next in this circuit. */
-  or_connection_t *n_conn;
+  cell_queue_t n_chan_cells;
+  /** The channel that is next in this circuit. */
+  channel_t *n_chan;
   /** The circuit_id used in the next (forward) hop of this circuit. */
   circid_t n_circ_id;
 
@@ -2600,12 +2600,12 @@ typedef struct circuit_t {
    * the circuit has attached to a connection. */
   extend_info_t *n_hop;
 
-  /** True iff we are waiting for n_conn_cells to become less full before
+  /** True iff we are waiting for n_chan_cells to become less full before
    * allowing p_streams to add any more cells. (Origin circuit only.) */
-  unsigned int streams_blocked_on_n_conn : 1;
-  /** True iff we are waiting for p_conn_cells to become less full before
+  unsigned int streams_blocked_on_n_chan : 1;
+  /** True iff we are waiting for p_chan_cells to become less full before
    * allowing n_streams to add any more cells. (OR circuit only.) */
-  unsigned int streams_blocked_on_p_conn : 1;
+  unsigned int streams_blocked_on_p_chan : 1;
 
   uint8_t state; /**< Current status of this circuit. */
   uint8_t purpose; /**< Why are we creating this circuit? */
@@ -2620,10 +2620,10 @@ typedef struct circuit_t {
    * more. */
   int deliver_window;
 
-  /** For storage while n_conn is pending
-    * (state CIRCUIT_STATE_OR_WAIT). When defined, it is always
+  /** For storage while n_chan is pending
+    * (state CIRCUIT_STATE_CHAN_WAIT). When defined, it is always
     * length ONIONSKIN_CHALLENGE_LEN. */
-  char *n_conn_onionskin;
+  char *n_chan_onionskin;
 
   /** When was this circuit created?  We keep this timestamp with a higher
    * resolution than most so that the circuit-build-time tracking code can
@@ -2652,11 +2652,11 @@ typedef struct circuit_t {
   /** Next circuit in the doubly-linked ring of circuits waiting to add
    * cells to n_conn.  NULL if we have no cells pending, or if we're not
    * linked to an OR connection. */
-  struct circuit_t *next_active_on_n_conn;
+  struct circuit_t *next_active_on_n_chan;
   /** Previous circuit in the doubly-linked ring of circuits waiting to add
    * cells to n_conn.  NULL if we have no cells pending, or if we're not
    * linked to an OR connection. */
-  struct circuit_t *prev_active_on_n_conn;
+  struct circuit_t *prev_active_on_n_chan;
   struct circuit_t *next; /**< Next circuit in linked list of all circuits. */
 
   /** Unique ID for measuring tunneled network status requests. */
@@ -2828,20 +2828,20 @@ typedef struct or_circuit_t {
   circuit_t _base;
 
   /** Next circuit in the doubly-linked ring of circuits waiting to add
-   * cells to p_conn.  NULL if we have no cells pending, or if we're not
+   * cells to p_chan.  NULL if we have no cells pending, or if we're not
    * linked to an OR connection. */
-  struct circuit_t *next_active_on_p_conn;
+  struct circuit_t *next_active_on_p_chan;
   /** Previous circuit in the doubly-linked ring of circuits waiting to add
-   * cells to p_conn.  NULL if we have no cells pending, or if we're not
+   * cells to p_chan.  NULL if we have no cells pending, or if we're not
    * linked to an OR connection. */
-  struct circuit_t *prev_active_on_p_conn;
+  struct circuit_t *prev_active_on_p_chan;
 
   /** The circuit_id used in the previous (backward) hop of this circuit. */
   circid_t p_circ_id;
   /** Queue of cells waiting to be transmitted on p_conn. */
-  cell_queue_t p_conn_cells;
-  /** The OR connection that is previous in this circuit. */
-  or_connection_t *p_conn;
+  cell_queue_t p_chan_cells;
+  /** The channel that is previous in this circuit. */
+  channel_t *p_chan;
   /** 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
diff --git a/src/or/reasons.c b/src/or/reasons.c
index c51d8ee6f5..a04cd869a2 100644
--- a/src/or/reasons.c
+++ b/src/or/reasons.c
@@ -323,8 +323,8 @@ circuit_end_reason_to_control_string(int reason)
       return "CONNECTFAILED";
     case END_CIRC_REASON_OR_IDENTITY:
       return "OR_IDENTITY";
-    case END_CIRC_REASON_OR_CONN_CLOSED:
-      return "OR_CONN_CLOSED";
+    case END_CIRC_REASON_CHANNEL_CLOSED:
+      return "CHANNEL_CLOSED";
     case END_CIRC_REASON_FINISHED:
       return "FINISHED";
     case END_CIRC_REASON_TIMEOUT:
diff --git a/src/or/relay.h b/src/or/relay.h
index 41675e2106..a41465521a 100644
--- a/src/or/relay.h
+++ b/src/or/relay.h
@@ -45,15 +45,15 @@ void cell_queue_clear(cell_queue_t *queue);
 void cell_queue_append(cell_queue_t *queue, packed_cell_t *cell);
 void cell_queue_append_packed_copy(cell_queue_t *queue, const cell_t *cell);
 
-void append_cell_to_circuit_queue(circuit_t *circ, or_connection_t *orconn,
+void append_cell_to_circuit_queue(circuit_t *circ, channel_t *chan,
                                   cell_t *cell, cell_direction_t direction,
                                   streamid_t fromstream);
-void connection_or_unlink_all_active_circs(or_connection_t *conn);
-int connection_or_flush_from_first_active_circuit(or_connection_t *conn,
-                                                  int max, time_t now);
+void channel_unlink_all_active_circs(channel_t *chan);
+int channel_flush_from_first_active_circuit(channel_t *conn,
+                                            int max, time_t now);
 void assert_active_circuits_ok(or_connection_t *orconn);
-void make_circuit_inactive_on_conn(circuit_t *circ, or_connection_t *conn);
-void make_circuit_active_on_conn(circuit_t *circ, or_connection_t *conn);
+void make_circuit_inactive_on_chan(circuit_t *circ, channel_t *chan);
+void make_circuit_active_on_chan(circuit_t *circ, channel_t *chan);
 
 int append_address_to_payload(uint8_t *payload_out, const tor_addr_t *addr);
 const uint8_t *decode_address_from_payload(tor_addr_t *addr_out,
@@ -62,7 +62,7 @@ const uint8_t *decode_address_from_payload(tor_addr_t *addr_out,
 unsigned cell_ewma_get_tick(void);
 void cell_ewma_set_scale_factor(const or_options_t *options,
                                 const networkstatus_t *consensus);
-void circuit_clear_cell_queue(circuit_t *circ, or_connection_t *orconn);
+void circuit_clear_cell_queue(circuit_t *circ, channel_t *chan);
 
 #ifdef RELAY_PRIVATE
 int relay_crypt(circuit_t *circ, cell_t *cell, cell_direction_t cell_direction,