Refactor listener_connection_t into its own type.

This will allow us to add more fields to listener_connection_t
without bloating the other connection types.

src/or/connection.c

@@ -76,6 +76,15 @@ static uint32_t last_interface_ip = 0;
  * Used to detect IP address changes. */
 static smartlist_t *outgoing_addrs = NULL;
 
+#define CASE_ANY_LISTENER_TYPE \
+    case CONN_TYPE_OR_LISTENER: \
+    case CONN_TYPE_AP_LISTENER: \
+    case CONN_TYPE_DIR_LISTENER: \
+    case CONN_TYPE_CONTROL_LISTENER: \
+    case CONN_TYPE_AP_TRANS_LISTENER: \
+    case CONN_TYPE_AP_NATD_LISTENER: \
+    case CONN_TYPE_AP_DNS_LISTENER
+
 /**************************************************************/
 
 /**
@@ -116,13 +125,7 @@ conn_state_to_string(int type, int state)
 {
   static char buf[96];
   switch (type) {
-    case CONN_TYPE_OR_LISTENER:
-    case CONN_TYPE_AP_LISTENER:
-    case CONN_TYPE_AP_TRANS_LISTENER:
-    case CONN_TYPE_AP_NATD_LISTENER:
-    case CONN_TYPE_AP_DNS_LISTENER:
-    case CONN_TYPE_DIR_LISTENER:
-    case CONN_TYPE_CONTROL_LISTENER:
+    CASE_ANY_LISTENER_TYPE:
       if (state == LISTENER_STATE_READY)
         return "ready";
       break;
@@ -265,6 +268,17 @@ control_connection_new(int socket_family)
   return control_conn;
 }
 
+/** Allocate and return a new listener_connection_t, initialized as by
+ * connection_init(). */
+listener_connection_t *
+listener_connection_new(int type, int socket_family)
+{
+  listener_connection_t *listener_conn =
+    tor_malloc_zero(sizeof(listener_connection_t));
+  connection_init(time(NULL), TO_CONN(listener_conn), type, socket_family);
+  return listener_conn;
+}
+
 /** Allocate, initialize, and return a new connection_t subtype of <b>type</b>
  * to make or receive connections of address family <b>socket_family</b>.  The
  * type should be one of the CONN_TYPE_* constants. */
@@ -285,6 +299,9 @@ connection_new(int type, int socket_family)
     case CONN_TYPE_CONTROL:
       return TO_CONN(control_connection_new(socket_family));
 
+    CASE_ANY_LISTENER_TYPE:
+      return TO_CONN(listener_connection_new(type, socket_family));
+
     default: {
       connection_t *conn = tor_malloc_zero(sizeof(connection_t));
       connection_init(time(NULL), conn, type, socket_family);
@@ -325,6 +342,8 @@ connection_init(time_t now, connection_t *conn, int type, int socket_family)
     case CONN_TYPE_CONTROL:
       conn->magic = CONTROL_CONNECTION_MAGIC;
       break;
+    CASE_ANY_LISTENER_TYPE:
+      conn->magic = LISTENER_CONNECTION_MAGIC;
     default:
       conn->magic = BASE_CONNECTION_MAGIC;
       break;
@@ -396,6 +415,11 @@ _connection_free(connection_t *conn)
       mem = TO_CONTROL_CONN(conn);
       memlen = sizeof(control_connection_t);
       break;
+    CASE_ANY_LISTENER_TYPE:
+      tor_assert(conn->magic == LISTENER_CONNECTION_MAGIC);
+      mem = TO_LISTENER_CONN(conn);
+      memlen = sizeof(listener_connection_t);
+      break;
     default:
       tor_assert(conn->magic == BASE_CONNECTION_MAGIC);
       mem = conn;
@@ -3970,13 +3994,7 @@ assert_connection_ok(connection_t *conn, time_t now)
 
   switch (conn->type)
     {
-    case CONN_TYPE_OR_LISTENER:
-    case CONN_TYPE_AP_LISTENER:
-    case CONN_TYPE_AP_TRANS_LISTENER:
-    case CONN_TYPE_AP_NATD_LISTENER:
-    case CONN_TYPE_DIR_LISTENER:
-    case CONN_TYPE_CONTROL_LISTENER:
-    case CONN_TYPE_AP_DNS_LISTENER:
+    CASE_ANY_LISTENER_TYPE:
       tor_assert(conn->state == LISTENER_STATE_READY);
       break;
     case CONN_TYPE_OR:

src/or/connection.h

@@ -22,6 +22,7 @@ dir_connection_t *dir_connection_new(int socket_family);
 or_connection_t *or_connection_new(int socket_family);
 edge_connection_t *edge_connection_new(int type, int socket_family);
 control_connection_t *control_connection_new(int socket_family);
+listener_connection_t *listener_connection_new(int type, int socket_family);
 connection_t *connection_new(int type, int socket_family);
 
 void connection_link_connections(connection_t *conn_a, connection_t *conn_b);

src/or/dnsserv.c

@@ -305,11 +305,13 @@ dnsserv_resolved(edge_connection_t *conn,
 void
 dnsserv_configure_listener(connection_t *conn)
 {
+  listener_connection_t *listener_conn;
   tor_assert(conn);
   tor_assert(SOCKET_OK(conn->s));
   tor_assert(conn->type == CONN_TYPE_AP_DNS_LISTENER);
 
-  conn->dns_server_port =
+  listener_conn = TO_LISTENER_CONN(conn);
+  listener_conn->dns_server_port =
     tor_evdns_add_server_port(conn->s, 0, evdns_server_callback, NULL);
 }
 
@@ -318,12 +320,15 @@ dnsserv_configure_listener(connection_t *conn)
 void
 dnsserv_close_listener(connection_t *conn)
 {
+  listener_connection_t *listener_conn;
   tor_assert(conn);
   tor_assert(conn->type == CONN_TYPE_AP_DNS_LISTENER);
 
-  if (conn->dns_server_port) {
-    evdns_close_server_port(conn->dns_server_port);
-    conn->dns_server_port = NULL;
+  listener_conn = TO_LISTENER_CONN(conn);
+
+  if (listener_conn->dns_server_port) {
+    evdns_close_server_port(listener_conn->dns_server_port);
+    listener_conn->dns_server_port = NULL;
   }
 }
 

src/or/main.c

@@ -290,7 +290,7 @@ connection_unregister_events(connection_t *conn)
     conn->bufev = NULL;
   }
 #endif
-  if (conn->dns_server_port) {
+  if (conn->type == CONN_TYPE_AP_DNS_LISTENER) {
     dnsserv_close_listener(conn);
   }
 }

src/or/or.h

@@ -938,6 +938,7 @@ typedef struct socks_request_t socks_request_t;
 #define EDGE_CONNECTION_MAGIC 0xF0374013u
 #define DIR_CONNECTION_MAGIC 0x9988ffeeu
 #define CONTROL_CONNECTION_MAGIC 0x8abc765du
+#define LISTENER_CONNECTION_MAGIC 0x1a1ac741u
 
 /** Description of a connection to another host or process, and associated
  * data.
@@ -1043,15 +1044,18 @@ typedef struct connection_t {
   /** Unique identifier for this connection on this Tor instance. */
   uint64_t global_identifier;
 
-  /* XXXX023 move this field, and all the listener-only fields (just
-     socket_family, I think), into a new listener_connection_t subtype. */
+  /** Unique ID for measuring tunneled network status requests. */
+  uint64_t dirreq_id;
+} connection_t;
+
+typedef struct listener_connection_t {
+  connection_t _base;
+
   /** If the connection is a CONN_TYPE_AP_DNS_LISTENER, this field points
    * to the evdns_server_port it uses to listen to and answer connections. */
   struct evdns_server_port *dns_server_port;
 
-  /** Unique ID for measuring tunneled network status requests. */
-  uint64_t dirreq_id;
-} connection_t;
+} listener_connection_t;
 
 /** Stores flags and information related to the portion of a v2 Tor OR
  * connection handshake that happens after the TLS handshake is finished.
@@ -1321,6 +1325,9 @@ static edge_connection_t *TO_EDGE_CONN(connection_t *);
 /** Convert a connection_t* to an control_connection_t*; assert if the cast is
  * invalid. */
 static control_connection_t *TO_CONTROL_CONN(connection_t *);
+/** Convert a connection_t* to an listener_connection_t*; assert if the cast is
+ * invalid. */
+static listener_connection_t *TO_LISTENER_CONN(connection_t *);
 
 static INLINE or_connection_t *TO_OR_CONN(connection_t *c)
 {
@@ -1342,6 +1349,11 @@ static INLINE control_connection_t *TO_CONTROL_CONN(connection_t *c)
   tor_assert(c->magic == CONTROL_CONNECTION_MAGIC);
   return DOWNCAST(control_connection_t, c);
 }
+static INLINE listener_connection_t *TO_LISTENER_CONN(connection_t *c)
+{
+  tor_assert(c->magic == LISTENER_CONNECTION_MAGIC);
+  return DOWNCAST(listener_connection_t, c);
+}
 
 /* Conditional macros to help write code that works whether bufferevents are
    disabled or not.