r12759@Kushana: nickm | 2007-04-20 08:47:20 -0400

 Track the number of connection_t separately from the number of open sockets.  It is already possible to have connections that do not count: resolving conns, for one.  Once we move from socketpairs to linked conns, and once we do dns proxying, there will be lots of such connections.


svn:r9994

6 files changed, 75 insertions, 26 deletions

diff --git a/src/common/compat.c b/src/common/compat.c
index f15bb1fd38..e9e46275ef 100644
--- a/src/common/compat.c
+++ b/src/common/compat.c
@@ -468,6 +468,48 @@ touch_file(const char *fname)
   return 0;
 }
 
+/** Count of number of sockets currently open.  (Undercounts sockets opened by
+ * eventdns and libevent.) */
+static int n_sockets_open = 0;
+
+/** As close(), but guaranteed to work for sockets across platforms (including
+ * Windows, where close()ing a socket doesn't work. */
+void
+tor_close_socket(int s)
+{
+  /* On Windows, you have to call close() on fds returned by open(),
+   * and closesocket() on fds returned by socket().  On Unix, everything
+   * gets close()'d.  We abstract this difference by always using
+   * tor_close_socket to close sockets, and always using close() on
+   * files.
+   */
+#ifdef USE_BSOCKETS
+  bclose(s);
+#elif defined(MS_WINDOWS)
+  closesocket(s);
+#else
+  close(s);
+#endif
+  --n_sockets_open;
+}
+
+/** As socket(), but counts the number of open sockets. */
+int
+tor_open_socket(int domain, int type, int protocol)
+{
+  int s = socket(domain, type, protocol);
+  if (s >= 0)
+    ++n_sockets_open;
+  return s;
+}
+
+/** Return the number of sockets we currently have opened. */
+int
+get_n_open_sockets(void)
+{
+  return n_sockets_open;
+}
+
 /** Turn <b>socket</b> into a nonblocking socket.
  */
 void
@@ -537,7 +579,7 @@ tor_socketpair(int family, int type, int protocol, int fd[2])
       return -EINVAL;
     }
 
-    listener = socket(AF_INET, type, 0);
+    listener = tor_open_socket(AF_INET, type, 0);
     if (listener < 0)
       return -tor_socket_errno(-1);
     memset(&listen_addr, 0, sizeof(listen_addr));
@@ -550,7 +592,7 @@ tor_socketpair(int family, int type, int protocol, int fd[2])
     if (listen(listener, 1) == -1)
       goto tidy_up_and_fail;
 
-    connector = socket(AF_INET, type, 0);
+    connector = tor_open_socket(AF_INET, type, 0);
     if (connector < 0)
       goto tidy_up_and_fail;
     /* We want to find out the port number to connect to.  */
diff --git a/src/common/compat.h b/src/common/compat.h
index a6c339ee73..3f2abc1968 100644
--- a/src/common/compat.h
+++ b/src/common/compat.h
@@ -213,19 +213,10 @@ int touch_file(const char *fname);
 #endif
 
 /* ===== Net compatibility */
-#ifdef USE_BSOCKETS
-#define tor_close_socket(s) bclose(s)
-#elif defined(MS_WINDOWS)
-/** On Windows, you have to call close() on fds returned by open(),
- * and closesocket() on fds returned by socket().  On Unix, everything
- * gets close()'d.  We abstract this difference by always using
- * tor_close_socket to close sockets, and always using close() on
- * files.
- */
-#define tor_close_socket(s) closesocket(s)
-#else
-#define tor_close_socket(s) close(s)
-#endif
+
+void tor_close_socket(int s);
+int tor_open_socket(int domain, int type, int protocol);
+int get_n_open_sockets(void);
 
 #ifdef USE_BSOCKETS
 #define tor_socket_send(s, buf, len, flags) bsend(s, buf, len, flags)
diff --git a/src/common/util.c b/src/common/util.c
index a66edf4332..ff658b7069 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -1914,7 +1914,7 @@ get_interface_address(int severity, uint32_t *addr)
   tor_assert(addr);
   *addr = 0;
 
-  sock = socket(PF_INET,SOCK_DGRAM,IPPROTO_UDP);
+  sock = tor_open_socket(PF_INET,SOCK_DGRAM,IPPROTO_UDP);
   if (sock < 0) {
     int e = tor_socket_errno(-1);
     log_fn(severity, LD_NET, "unable to create socket: %s",
diff --git a/src/or/connection.c b/src/or/connection.c
index 2163c82349..165d1290bf 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -613,7 +613,16 @@ connection_create_listener(const char *listenaddress, uint16_t listenport,
   log_notice(LD_NET, "Opening %s on %s:%d",
              conn_type_to_string(type), address, usePort);
 
-  s = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
+  if (get_n_open_sockets() >= get_options()->_ConnLimit-1) {
+    int n_conns = get_n_open_sockets();
+    log_warn(LD_NET,"Failing because we have %d connections already. Please "
+             "raise your ulimit -n.", n_conns);
+    control_event_general_status(LOG_WARN, "TOO_MANY_CONNECTIONS CURRENT=%d",
+                                 n_conns);
+    return NULL;
+  }
+
+  s = tor_open_socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
   if (s < 0) {
     log_warn(LD_NET,"Socket creation failed.");
     goto err;
@@ -853,7 +862,16 @@ connection_connect(connection_t *conn, const char *address,
   struct sockaddr_in dest_addr;
   or_options_t *options = get_options();
 
-  s = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
+  if (get_n_open_sockets() >= get_options()->_ConnLimit-1) {
+    int n_conns = get_n_open_sockets();
+    log_warn(LD_NET,"Failing because we have %d connections already. Please "
+             "raise your ulimit -n.", n_conns);
+    control_event_general_status(LOG_WARN, "TOO_MANY_CONNECTIONS CURRENT=%d",
+                                 n_conns);
+    return -1;
+  }
+
+  s = tor_open_socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
   if (s < 0) {
     log_warn(LD_NET,"Error creating network socket: %s",
              tor_socket_strerror(tor_socket_errno(-1)));
diff --git a/src/or/main.c b/src/or/main.c
index 1249bafc74..f15b18243b 100644
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -68,6 +68,7 @@ static time_t time_of_last_signewnym = 0;
 static int signewnym_is_pending = 0;
 
 /** Array of all open connections.  The first n_conns elements are valid. */
+/*XXXX020 Should we just use a smartlist here? */
 static connection_t *connection_array[MAXCONNECTIONS+1] =
         { NULL };
 /** List of connections that have been marked for close and need to be freed
@@ -156,15 +157,12 @@ connection_add(connection_t *conn)
   tor_assert(conn);
   tor_assert(conn->s >= 0);
 
-  if (n_conns >= get_options()->_ConnLimit-1) {
-    log_warn(LD_NET,"Failing because we have %d connections already. Please "
-             "raise your ulimit -n.", n_conns);
-    control_event_general_status(LOG_WARN, "TOO_MANY_CONNECTIONS CURRENT=%d",
-                                 n_conns);
+  tor_assert(conn->conn_array_index == -1); /* can only connection_add once */
+  if (n_conns == MAXCONNECTIONS) {
+    log_warn(LD_BUG, "Unable to add a connection; MAXCONNECTIONS is set too "
+             "low.  This is a bug; tell the developers.");
     return -1;
   }
-
-  tor_assert(conn->conn_array_index == -1); /* can only connection_add once */
   conn->conn_array_index = n_conns;
   connection_array[n_conns] = conn;
 
diff --git a/src/tools/tor-resolve.c b/src/tools/tor-resolve.c
index 25a14a4660..71639140f8 100644
--- a/src/tools/tor-resolve.c
+++ b/src/tools/tor-resolve.c
@@ -153,7 +153,7 @@ do_resolve(const char *hostname, uint32_t sockshost, uint16_t socksport,
   *result_addr = 0;
   *result_hostname = NULL;
 
-  s = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
+  s = tor_open_socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
   if (s<0) {
     log_sock_error("creating_socket", -1);
     return -1;