Link libgnunetblockgroup to libgnunetblock
[oweals/gnunet.git] / src / util / connection.c
index e90fa9f51f50386c866881c0766b1e0ebc9a9f01..e822b264f47c50f5e99705512c0b1c0c7bf8e2ed 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2009-2013 Christian Grothoff (and other contributing authors)
+     Copyright (C) 2009-2013 GNUnet e.V.
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
@@ -14,8 +14,8 @@
 
      You should have received a copy of the GNU General Public License
      along with GNUnet; see the file COPYING.  If not, write to the
-     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-     Boston, MA 02111-1307, USA.
+     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+     Boston, MA 02110-1301, USA.
 */
 
 /**
@@ -35,9 +35,9 @@
 #include "gnunet_resolver_service.h"
 
 
-#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+#define LOG(kind,...) GNUNET_log_from (kind, "util-connection", __VA_ARGS__)
 
-#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)
+#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util-connection", syscall)
 
 
 /**
@@ -70,7 +70,7 @@ struct GNUNET_CONNECTION_TransmitHandle
   /**
    * Task called on timeout.
    */
-  GNUNET_SCHEDULER_TaskIdentifier timeout_task;
+  struct GNUNET_SCHEDULER_Task * timeout_task;
 
   /**
    * At what number of bytes available in the
@@ -121,7 +121,7 @@ struct AddressProbe
   /**
    * Task waiting for the connection to finish connecting.
    */
-  GNUNET_SCHEDULER_TaskIdentifier task;
+  struct GNUNET_SCHEDULER_Task * task;
 };
 
 
@@ -170,7 +170,7 @@ struct GNUNET_CONNECTION_Handle
   GNUNET_CONNECTION_Receiver receiver;
 
   /**
-   * Closure for receiver.
+   * Closure for @e receiver.
    */
   void *receiver_cls;
 
@@ -180,36 +180,36 @@ struct GNUNET_CONNECTION_Handle
   char *write_buffer;
 
   /**
-   * Current size of our write buffer.
+   * Current size of our @e write_buffer.
    */
   size_t write_buffer_size;
 
   /**
-   * Current write-offset in write buffer (where
+   * Current write-offset in @e write_buffer (where
    * would we write next).
    */
   size_t write_buffer_off;
 
   /**
-   * Current read-offset in write buffer (how many
+   * Current read-offset in @e write_buffer (how many
    * bytes have already been sent).
    */
   size_t write_buffer_pos;
 
   /**
-   * Length of addr.
+   * Length of @e addr.
    */
   socklen_t addrlen;
 
   /**
    * Read task that we may need to wait for.
    */
-  GNUNET_SCHEDULER_TaskIdentifier read_task;
+  struct GNUNET_SCHEDULER_Task *read_task;
 
   /**
    * Write task that we may need to wait for.
    */
-  GNUNET_SCHEDULER_TaskIdentifier write_task;
+  struct GNUNET_SCHEDULER_Task *write_task;
 
   /**
    * Handle to a pending DNS lookup request.
@@ -217,7 +217,7 @@ struct GNUNET_CONNECTION_Handle
   struct GNUNET_RESOLVER_RequestHandle *dns_active;
 
   /**
-   * The handle we return for GNUNET_CONNECTION_notify_transmit_ready.
+   * The handle we return for #GNUNET_CONNECTION_notify_transmit_ready().
    */
   struct GNUNET_CONNECTION_TransmitHandle nth;
 
@@ -245,12 +245,17 @@ struct GNUNET_CONNECTION_Handle
   int8_t persist;
 
   /**
-   * Usually 0.  Set to 1 if this handle is in used and should
-   * 'GNUNET_CONNECTION_destroy' be called right now, the action needs
+   * Usually 0.  Set to 1 if this handle is in use, and should
+   * #GNUNET_CONNECTION_destroy() be called right now, the action needs
    * to be deferred by setting it to -1.
    */
   int8_t destroy_later;
 
+  /**
+   * Handle to subsequent connection after proxy handshake completes,
+   */
+  struct GNUNET_CONNECTION_Handle *proxy_handshake;
+
 };
 
 
@@ -277,7 +282,7 @@ GNUNET_CONNECTION_persist_ (struct GNUNET_CONNECTION_Handle *connection)
  * reach the other side before the process is terminated.
  *
  * @param connection the connection to make flushing and blocking
- * @return GNUNET_OK on success
+ * @return #GNUNET_OK on success
  */
 int
 GNUNET_CONNECTION_disable_corking (struct GNUNET_CONNECTION_Handle *connection)
@@ -289,7 +294,7 @@ GNUNET_CONNECTION_disable_corking (struct GNUNET_CONNECTION_Handle *connection)
 /**
  * Create a connection handle by boxing an existing OS socket.  The OS
  * socket should henceforth be no longer used directly.
- * GNUNET_connection_destroy will close it.
+ * #GNUNET_connection_destroy() will close it.
  *
  * @param osSocket existing socket to box
  * @return the boxed connection handle
@@ -311,14 +316,14 @@ GNUNET_CONNECTION_create_from_existing (struct GNUNET_NETWORK_Handle *osSocket)
  * Create a connection handle by accepting on a listen socket.  This
  * function may block if the listen socket has no connection ready.
  *
- * @param access function to use to check if access is allowed
- * @param access_cls closure for access
+ * @param access_cb function to use to check if access is allowed
+ * @param access_cb_cls closure for @a access_cb
  * @param lsock listen socket
  * @return the connection handle, NULL on error
  */
 struct GNUNET_CONNECTION_Handle *
-GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
-                                      void *access_cls,
+GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access_cb,
+                                      void *access_cb_cls,
                                       struct GNUNET_NETWORK_Handle *lsock)
 {
   struct GNUNET_CONNECTION_Handle *connection;
@@ -330,19 +335,27 @@ GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
   struct sockaddr_in6 *v6;
   struct sockaddr *sa;
   void *uaddr;
-  struct GNUNET_CONNECTION_Credentials *gcp;
-  struct GNUNET_CONNECTION_Credentials gc;
 #ifdef SO_PEERCRED
   struct ucred uc;
   socklen_t olen;
 #endif
+  struct GNUNET_CONNECTION_Credentials *gcp;
+#if HAVE_GETPEEREID || defined(SO_PEERCRED) || HAVE_GETPEERUCRED
+  struct GNUNET_CONNECTION_Credentials gc;
+
+  gc.uid = 0;
+  gc.gid = 0;
+#endif
 
   addrlen = sizeof (addr);
   sock =
-      GNUNET_NETWORK_socket_accept (lsock, (struct sockaddr *) &addr, &addrlen);
+      GNUNET_NETWORK_socket_accept (lsock,
+                                   (struct sockaddr *) &addr,
+                                   &addrlen);
   if (NULL == sock)
   {
-    LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "accept");
+    if (EAGAIN != errno)
+      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "accept");
     return NULL;
   }
   if ((addrlen > sizeof (addr)) || (addrlen < sizeof (sa_family_t)))
@@ -354,7 +367,8 @@ GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
 
   sa = (struct sockaddr *) addr;
   v6 = (struct sockaddr_in6 *) addr;
-  if ((AF_INET6 == sa->sa_family) && (IN6_IS_ADDR_V4MAPPED (&v6->sin6_addr)))
+  if ( (AF_INET6 == sa->sa_family) &&
+       (IN6_IS_ADDR_V4MAPPED (&v6->sin6_addr)) )
   {
     /* convert to V4 address */
     v4 = GNUNET_new (struct sockaddr_in);
@@ -363,7 +377,7 @@ GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
 #if HAVE_SOCKADDR_IN_SIN_LEN
     v4->sin_len = (u_char) sizeof (struct sockaddr_in);
 #endif
-    memcpy (&v4->sin_addr,
+    GNUNET_memcpy (&v4->sin_addr,
             &((char *) &v6->sin6_addr)[sizeof (struct in6_addr) -
                                        sizeof (struct in_addr)],
             sizeof (struct in_addr));
@@ -374,24 +388,28 @@ GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
   else
   {
     uaddr = GNUNET_malloc (addrlen);
-    memcpy (uaddr, addr, addrlen);
+    GNUNET_memcpy (uaddr, addr, addrlen);
   }
   gcp = NULL;
-  gc.uid = 0;
-  gc.gid = 0;
   if (AF_UNIX == sa->sa_family)
   {
 #if HAVE_GETPEEREID
     /* most BSDs */
-    if (0 == getpeereid (GNUNET_NETWORK_get_fd (sock), &gc.uid, &gc.gid))
+    if (0 == getpeereid (GNUNET_NETWORK_get_fd (sock),
+                        &gc.uid,
+                        &gc.gid))
       gcp = &gc;
 #else
 #ifdef SO_PEERCRED
     /* largely traditional GNU/Linux */
     olen = sizeof (uc);
-    if ((0 ==
-         getsockopt (GNUNET_NETWORK_get_fd (sock), SOL_SOCKET, SO_PEERCRED, &uc,
-                     &olen)) && (olen == sizeof (uc)))
+    if ( (0 ==
+         getsockopt (GNUNET_NETWORK_get_fd (sock),
+                     SOL_SOCKET,
+                     SO_PEERCRED,
+                     &uc,
+                     &olen)) &&
+        (olen == sizeof (uc)) )
     {
       gc.uid = uc.uid;
       gc.gid = uc.gid;
@@ -415,14 +433,20 @@ GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
 #endif
   }
 
-  if ((NULL != access) &&
-      (GNUNET_YES != (aret = access (access_cls, gcp, uaddr, addrlen))))
+  if ( (NULL != access_cb) &&
+       (GNUNET_YES != (aret = access_cb (access_cb_cls,
+                                        gcp,
+                                        uaddr,
+                                        addrlen))) )
   {
     if (GNUNET_NO == aret)
-      LOG (GNUNET_ERROR_TYPE_INFO, _("Access denied to `%s'\n"),
-           GNUNET_a2s (uaddr, addrlen));
+      LOG (GNUNET_ERROR_TYPE_INFO,
+           _("Access denied to `%s'\n"),
+           GNUNET_a2s (uaddr,
+                       addrlen));
     GNUNET_break (GNUNET_OK ==
-                  GNUNET_NETWORK_socket_shutdown (sock, SHUT_RDWR));
+                  GNUNET_NETWORK_socket_shutdown (sock,
+                                                  SHUT_RDWR));
     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
     GNUNET_free (uaddr);
     return NULL;
@@ -433,9 +457,11 @@ GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
   connection->addr = uaddr;
   connection->addrlen = addrlen;
   connection->sock = sock;
-  LOG (GNUNET_ERROR_TYPE_INFO, 
+  LOG (GNUNET_ERROR_TYPE_INFO,
        _("Accepting connection from `%s': %p\n"),
-       GNUNET_a2s (uaddr, addrlen), connection);
+       GNUNET_a2s (uaddr,
+                  addrlen),
+       connection);
   return connection;
 }
 
@@ -445,17 +471,18 @@ GNUNET_CONNECTION_create_from_accept (GNUNET_CONNECTION_AccessCheck access,
  *
  * @param connection the client to get the address for
  * @param addr where to store the address
- * @param addrlen where to store the length of the address
- * @return GNUNET_OK on success
+ * @param addrlen where to store the length of the @a addr
+ * @return #GNUNET_OK on success
  */
 int
 GNUNET_CONNECTION_get_address (struct GNUNET_CONNECTION_Handle *connection,
-                               void **addr, size_t * addrlen)
+                               void **addr,
+                               size_t *addrlen)
 {
   if ((NULL == connection->addr) || (0 == connection->addrlen))
     return GNUNET_NO;
   *addr = GNUNET_malloc (connection->addrlen);
-  memcpy (*addr, connection->addr, connection->addrlen);
+  GNUNET_memcpy (*addr, connection->addr, connection->addrlen);
   *addrlen = connection->addrlen;
   return GNUNET_OK;
 }
@@ -468,17 +495,23 @@ GNUNET_CONNECTION_get_address (struct GNUNET_CONNECTION_Handle *connection,
  * @param errcode error code to send
  */
 static void
-signal_receive_error (struct GNUNET_CONNECTION_Handle *connection, int errcode)
+signal_receive_error (struct GNUNET_CONNECTION_Handle *connection,
+                      int errcode)
 {
   GNUNET_CONNECTION_Receiver receiver;
 
   LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Receive encounters error (%s), connection closed (%p)\n", 
+       "Receive encounters error (%s), connection closed (%p)\n",
        STRERROR (errcode),
        connection);
   GNUNET_assert (NULL != (receiver = connection->receiver));
   connection->receiver = NULL;
-  receiver (connection->receiver_cls, NULL, 0, connection->addr, connection->addrlen, errcode);
+  receiver (connection->receiver_cls,
+            NULL,
+            0,
+            connection->addr,
+            connection->addrlen,
+            errcode);
 }
 
 
@@ -492,7 +525,8 @@ signal_receive_timeout (struct GNUNET_CONNECTION_Handle *connection)
 {
   GNUNET_CONNECTION_Receiver receiver;
 
-  LOG (GNUNET_ERROR_TYPE_DEBUG, "Connection signals timeout to receiver (%p)!\n",
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Connection signals timeout to receiver (%p)!\n",
        connection);
   GNUNET_assert (NULL != (receiver = connection->receiver));
   connection->receiver = NULL;
@@ -518,16 +552,18 @@ signal_transmit_error (struct GNUNET_CONNECTION_Handle *connection,
        connection);
   if (NULL != connection->sock)
   {
-    GNUNET_NETWORK_socket_shutdown (connection->sock, SHUT_RDWR);
-    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (connection->sock));
+    (void) GNUNET_NETWORK_socket_shutdown (connection->sock,
+                                           SHUT_RDWR);
+    GNUNET_break (GNUNET_OK ==
+                  GNUNET_NETWORK_socket_close (connection->sock));
     connection->sock = NULL;
-    GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == connection->write_task);
+    GNUNET_assert (NULL == connection->write_task);
   }
-  if (GNUNET_SCHEDULER_NO_TASK != connection->read_task)
+  if (NULL != connection->read_task)
   {
     /* send errors trigger read errors... */
     GNUNET_SCHEDULER_cancel (connection->read_task);
-    connection->read_task = GNUNET_SCHEDULER_NO_TASK;
+    connection->read_task = NULL;
     signal_receive_timeout (connection);
     return;
   }
@@ -535,7 +571,9 @@ signal_transmit_error (struct GNUNET_CONNECTION_Handle *connection,
     return;                     /* nobody to tell about it */
   notify = connection->nth.notify_ready;
   connection->nth.notify_ready = NULL;
-  notify (connection->nth.notify_ready_cls, 0, NULL);
+  notify (connection->nth.notify_ready_cls,
+         0,
+         NULL);
 }
 
 
@@ -549,24 +587,28 @@ static void
 connect_fail_continuation (struct GNUNET_CONNECTION_Handle *connection)
 {
   LOG (GNUNET_ERROR_TYPE_INFO,
-       _("Failed to establish TCP connection to `%s:%u', no further addresses to try.\n"),
-       connection->hostname, connection->port);
+       "Failed to establish TCP connection to `%s:%u', no further addresses to try.\n",
+       connection->hostname,
+    connection->port);
   GNUNET_break (NULL == connection->ap_head);
   GNUNET_break (NULL == connection->ap_tail);
   GNUNET_break (GNUNET_NO == connection->dns_active);
   GNUNET_break (NULL == connection->sock);
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == connection->write_task);
+  GNUNET_assert (NULL == connection->write_task);
+  GNUNET_assert (NULL == connection->proxy_handshake);
 
   /* signal errors for jobs that used to wait on the connection */
   connection->destroy_later = 1;
   if (NULL != connection->receiver)
-    signal_receive_error (connection, ECONNREFUSED);
+    signal_receive_error (connection,
+                          ECONNREFUSED);
   if (NULL != connection->nth.notify_ready)
   {
-    GNUNET_assert (connection->nth.timeout_task != GNUNET_SCHEDULER_NO_TASK);
+    GNUNET_assert (NULL != connection->nth.timeout_task);
     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
-    connection->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
-    signal_transmit_error (connection, ECONNREFUSED);
+    connection->nth.timeout_task = NULL;
+    signal_transmit_error (connection,
+                           ECONNREFUSED);
   }
   if (-1 == connection->destroy_later)
   {
@@ -583,10 +625,9 @@ connect_fail_continuation (struct GNUNET_CONNECTION_Handle *connection)
  * We are ready to transmit (or got a timeout).
  *
  * @param cls our connection handle
- * @param tc task context describing why we are here
  */
 static void
-transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
+transmit_ready (void *cls);
 
 
 /**
@@ -594,10 +635,9 @@ transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
  * to read.
  *
  * @param cls connection to read from
- * @param tc scheduler context
  */
 static void
-receive_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
+receive_ready (void *cls);
 
 
 /**
@@ -608,19 +648,22 @@ receive_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
 static void
 connect_success_continuation (struct GNUNET_CONNECTION_Handle *connection)
 {
-  LOG (GNUNET_ERROR_TYPE_DEBUG, 
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Connection to `%s' succeeded! (%p)\n",
-       GNUNET_a2s (connection->addr, connection->addrlen), connection);
+       GNUNET_a2s (connection->addr,
+                  connection->addrlen),
+       connection);
   /* trigger jobs that waited for the connection */
   if (NULL != connection->receiver)
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
-         "Connection succeeded, starting with receiving data (%p)\n", 
+         "Connection succeeded, starting with receiving data (%p)\n",
         connection);
-    GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == connection->read_task);
+    GNUNET_assert (NULL == connection->read_task);
     connection->read_task =
       GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining
-                                     (connection->receive_timeout), connection->sock,
+                                     (connection->receive_timeout),
+                                    connection->sock,
                                      &receive_ready, connection);
   }
   if (NULL != connection->nth.notify_ready)
@@ -628,10 +671,10 @@ connect_success_continuation (struct GNUNET_CONNECTION_Handle *connection)
     LOG (GNUNET_ERROR_TYPE_DEBUG,
          "Connection succeeded, starting with sending data (%p)\n",
          connection);
-    GNUNET_assert (connection->nth.timeout_task != GNUNET_SCHEDULER_NO_TASK);
+    GNUNET_assert (connection->nth.timeout_task != NULL);
     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
-    connection->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
-    GNUNET_assert (connection->write_task == GNUNET_SCHEDULER_NO_TASK);
+    connection->nth.timeout_task = NULL;
+    GNUNET_assert (connection->write_task == NULL);
     connection->write_task =
         GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_absolute_get_remaining
                                         (connection->nth.transmit_timeout), connection->sock,
@@ -644,32 +687,41 @@ connect_success_continuation (struct GNUNET_CONNECTION_Handle *connection)
  * Scheduler let us know that we're either ready to write on the
  * socket OR connect timed out.  Do the right thing.
  *
- * @param cls the "struct AddressProbe*" with the address that we are probing
- * @param tc success or failure info about the connect attempt.
+ * @param cls the `struct AddressProbe *` with the address that we are probing
  */
 static void
-connect_probe_continuation (void *cls,
-                            const struct GNUNET_SCHEDULER_TaskContext *tc)
+connect_probe_continuation (void *cls)
 {
   struct AddressProbe *ap = cls;
   struct GNUNET_CONNECTION_Handle *connection = ap->connection;
+  const struct GNUNET_SCHEDULER_TaskContext *tc;
   struct AddressProbe *pos;
   int error;
   socklen_t len;
 
   GNUNET_assert (NULL != ap->sock);
-  GNUNET_CONTAINER_DLL_remove (connection->ap_head, connection->ap_tail, ap);
+  GNUNET_CONTAINER_DLL_remove (connection->ap_head,
+                              connection->ap_tail,
+                              ap);
   len = sizeof (error);
   errno = 0;
   error = 0;
-  if ((0 == (tc->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) ||
-      (GNUNET_OK !=
-       GNUNET_NETWORK_socket_getsockopt (ap->sock, SOL_SOCKET, SO_ERROR, &error,
-                                         &len)) || (0 != error))
+  tc = GNUNET_SCHEDULER_get_task_context ();
+  if ( (0 == (tc->reason & GNUNET_SCHEDULER_REASON_WRITE_READY)) ||
+       (GNUNET_OK !=
+       GNUNET_NETWORK_socket_getsockopt (ap->sock,
+                                         SOL_SOCKET,
+                                         SO_ERROR,
+                                         &error,
+                                         &len)) ||
+       (0 != error) )
   {
-    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (ap->sock));
+    GNUNET_break (GNUNET_OK ==
+                 GNUNET_NETWORK_socket_close (ap->sock));
     GNUNET_free (ap);
-    if ((NULL == connection->ap_head) && (GNUNET_NO == connection->dns_active))
+    if ( (NULL == connection->ap_head) &&
+        (GNUNET_NO == connection->dns_active) &&
+        (NULL == connection->proxy_handshake) )
       connect_fail_continuation (connection);
     return;
   }
@@ -677,7 +729,7 @@ connect_probe_continuation (void *cls,
   connection->sock = ap->sock;
   GNUNET_assert (NULL == connection->addr);
   connection->addr = GNUNET_malloc (ap->addrlen);
-  memcpy (connection->addr, ap->addr, ap->addrlen);
+  GNUNET_memcpy (connection->addr, ap->addr, ap->addrlen);
   connection->addrlen = ap->addrlen;
   GNUNET_free (ap);
   /* cancel all other attempts */
@@ -685,7 +737,9 @@ connect_probe_continuation (void *cls,
   {
     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
     GNUNET_SCHEDULER_cancel (pos->task);
-    GNUNET_CONTAINER_DLL_remove (connection->ap_head, connection->ap_tail, pos);
+    GNUNET_CONTAINER_DLL_remove (connection->ap_head,
+                                connection->ap_tail,
+                                pos);
     GNUNET_free (pos);
   }
   connect_success_continuation (connection);
@@ -696,12 +750,13 @@ connect_probe_continuation (void *cls,
  * Try to establish a connection given the specified address.
  * This function is called by the resolver once we have a DNS reply.
  *
- * @param cls our "struct GNUNET_CONNECTION_Handle *"
+ * @param cls our `struct GNUNET_CONNECTION_Handle *`
  * @param addr address to try, NULL for "last call"
- * @param addrlen length of addr
+ * @param addrlen length of @a addr
  */
 static void
-try_connect_using_address (void *cls, const struct sockaddr *addr,
+try_connect_using_address (void *cls,
+                           const struct sockaddr *addr,
                            socklen_t addrlen)
 {
   struct GNUNET_CONNECTION_Handle *connection = cls;
@@ -711,7 +766,9 @@ try_connect_using_address (void *cls, const struct sockaddr *addr,
   if (NULL == addr)
   {
     connection->dns_active = NULL;
-    if ((NULL == connection->ap_head) && (NULL == connection->sock))
+    if ((NULL == connection->ap_head) &&
+        (NULL == connection->sock) &&
+        (NULL == connection->proxy_handshake))
       connect_fail_continuation (connection);
     return;
   }
@@ -720,11 +777,14 @@ try_connect_using_address (void *cls, const struct sockaddr *addr,
   GNUNET_assert (NULL == connection->addr);
   /* try to connect */
   LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Trying to connect using address `%s:%u/%s:%u'\n", connection->hostname, connection->port,
-       GNUNET_a2s (addr, addrlen), connection->port);
+       "Trying to connect using address `%s:%u/%s:%u'\n",
+       connection->hostname,
+       connection->port,
+       GNUNET_a2s (addr, addrlen),
+       connection->port);
   ap = GNUNET_malloc (sizeof (struct AddressProbe) + addrlen);
   ap->addr = (const struct sockaddr *) &ap[1];
-  memcpy (&ap[1], addr, addrlen);
+  GNUNET_memcpy (&ap[1], addr, addrlen);
   ap->addrlen = addrlen;
   ap->connection = connection;
 
@@ -741,16 +801,21 @@ try_connect_using_address (void *cls, const struct sockaddr *addr,
     GNUNET_free (ap);
     return;                     /* not supported by us */
   }
-  ap->sock = GNUNET_NETWORK_socket_create (ap->addr->sa_family, SOCK_STREAM, 0);
+  ap->sock = GNUNET_NETWORK_socket_create (ap->addr->sa_family,
+                                          SOCK_STREAM, 0);
   if (NULL == ap->sock)
   {
     GNUNET_free (ap);
     return;                     /* not supported by OS */
   }
-  LOG (GNUNET_ERROR_TYPE_INFO, _("Trying to connect to `%s' (%p)\n"),
-       GNUNET_a2s (ap->addr, ap->addrlen), connection);
+  LOG (GNUNET_ERROR_TYPE_INFO,
+       "Trying to connect to `%s' (%p)\n",
+       GNUNET_a2s (ap->addr, ap->addrlen),
+       connection);
   if ((GNUNET_OK !=
-       GNUNET_NETWORK_socket_connect (ap->sock, ap->addr, ap->addrlen)) &&
+       GNUNET_NETWORK_socket_connect (ap->sock,
+                                     ap->addr,
+                                     ap->addrlen)) &&
       (EINPROGRESS != errno))
   {
     /* maybe refused / unsupported address, try next */
@@ -762,18 +827,15 @@ try_connect_using_address (void *cls, const struct sockaddr *addr,
   GNUNET_CONTAINER_DLL_insert (connection->ap_head, connection->ap_tail, ap);
   delay = GNUNET_CONNECTION_CONNECT_RETRY_TIMEOUT;
   if (NULL != connection->nth.notify_ready)
-    delay =
-        GNUNET_TIME_relative_min (delay,
-                                  GNUNET_TIME_absolute_get_remaining (connection->
-                                                                      nth.transmit_timeout));
+    delay = GNUNET_TIME_relative_min (delay,
+                                     GNUNET_TIME_absolute_get_remaining (connection->nth.transmit_timeout));
   if (NULL != connection->receiver)
-    delay =
-        GNUNET_TIME_relative_min (delay,
-                                  GNUNET_TIME_absolute_get_remaining
-                                  (connection->receive_timeout));
-  ap->task =
-      GNUNET_SCHEDULER_add_write_net (delay, ap->sock,
-                                      &connect_probe_continuation, ap);
+    delay = GNUNET_TIME_relative_min (delay,
+                                     GNUNET_TIME_absolute_get_remaining (connection->receive_timeout));
+  ap->task = GNUNET_SCHEDULER_add_write_net (delay,
+                                            ap->sock,
+                                            &connect_probe_continuation,
+                                            ap);
 }
 
 
@@ -788,8 +850,8 @@ try_connect_using_address (void *cls, const struct sockaddr *addr,
  * @return the connection handle
  */
 struct GNUNET_CONNECTION_Handle *
-GNUNET_CONNECTION_create_from_connect (const struct GNUNET_CONFIGURATION_Handle
-                                       *cfg, const char *hostname,
+GNUNET_CONNECTION_create_from_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                                       const char *hostname,
                                        uint16_t port)
 {
   struct GNUNET_CONNECTION_Handle *connection;
@@ -802,9 +864,11 @@ GNUNET_CONNECTION_create_from_connect (const struct GNUNET_CONFIGURATION_Handle
   connection->port = port;
   connection->hostname = GNUNET_strdup (hostname);
   connection->dns_active =
-      GNUNET_RESOLVER_ip_get (connection->hostname, AF_UNSPEC,
+      GNUNET_RESOLVER_ip_get (connection->hostname,
+                             AF_UNSPEC,
                               GNUNET_CONNECTION_CONNECT_RETRY_TIMEOUT,
-                              &try_connect_using_address, connection);
+                              &try_connect_using_address,
+                             connection);
   return connection;
 }
 
@@ -819,29 +883,30 @@ GNUNET_CONNECTION_create_from_connect (const struct GNUNET_CONFIGURATION_Handle
  * @return the connection handle, NULL on systems without UNIX support
  */
 struct GNUNET_CONNECTION_Handle *
-GNUNET_CONNECTION_create_from_connect_to_unixpath (const struct
-                                                   GNUNET_CONFIGURATION_Handle
-                                                   *cfg, const char *unixpath)
+GNUNET_CONNECTION_create_from_connect_to_unixpath (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                                                   const char *unixpath)
 {
 #ifdef AF_UNIX
   struct GNUNET_CONNECTION_Handle *connection;
   struct sockaddr_un *un;
-  size_t slen;
 
   GNUNET_assert (0 < strlen (unixpath));        /* sanity check */
   un = GNUNET_new (struct sockaddr_un);
   un->sun_family = AF_UNIX;
-  slen = strlen (unixpath);
-  if (slen >= sizeof (un->sun_path))
-    slen = sizeof (un->sun_path) - 1;
-  memcpy (un->sun_path, unixpath, slen);
-  un->sun_path[slen] = '\0';
-  slen = sizeof (struct sockaddr_un);
-#if HAVE_SOCKADDR_IN_SIN_LEN
-  un->sun_len = (u_char) slen;
+  strncpy (un->sun_path, unixpath, sizeof (un->sun_path) - 1);
+#ifdef LINUX
+  {
+    int abstract;
+
+    abstract = GNUNET_CONFIGURATION_get_value_yesno (cfg,
+                                                    "TESTING",
+                                                     "USE_ABSTRACT_SOCKETS");
+    if (GNUNET_YES == abstract)
+      un->sun_path[0] = '\0';
+  }
 #endif
-#if LINUX
-  un->sun_path[0] = '\0';
+#if HAVE_SOCKADDR_UN_SUN_LEN
+  un->sun_len = (u_char) sizeof (struct sockaddr_un);
 #endif
   connection = GNUNET_new (struct GNUNET_CONNECTION_Handle);
   connection->cfg = cfg;
@@ -850,8 +915,10 @@ GNUNET_CONNECTION_create_from_connect_to_unixpath (const struct
   connection->port = 0;
   connection->hostname = NULL;
   connection->addr = (struct sockaddr *) un;
-  connection->addrlen = slen;
-  connection->sock = GNUNET_NETWORK_socket_create (AF_UNIX, SOCK_STREAM, 0);
+  connection->addrlen = sizeof (struct sockaddr_un);
+  connection->sock = GNUNET_NETWORK_socket_create (AF_UNIX,
+                                                  SOCK_STREAM,
+                                                  0);
   if (NULL == connection->sock)
   {
     GNUNET_free (connection->addr);
@@ -860,11 +927,14 @@ GNUNET_CONNECTION_create_from_connect_to_unixpath (const struct
     return NULL;
   }
   if ( (GNUNET_OK !=
-       GNUNET_NETWORK_socket_connect (connection->sock, connection->addr, connection->addrlen)) &&
+       GNUNET_NETWORK_socket_connect (connection->sock,
+                                      connection->addr,
+                                      connection->addrlen)) &&
        (EINPROGRESS != errno) )
   {
     /* Just return; we expect everything to work eventually so don't fail HARD */
-    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (connection->sock));
+    GNUNET_break (GNUNET_OK ==
+                 GNUNET_NETWORK_socket_close (connection->sock));
     connection->sock = NULL;
     return connection;
   }
@@ -881,59 +951,94 @@ GNUNET_CONNECTION_create_from_connect_to_unixpath (const struct
  * This function returns immediately, even if the connection has not
  * yet been established.  This function only creates TCP connections.
  *
- * @param af_family address family to use
+ * @param s socket to connect
  * @param serv_addr server address
- * @param addrlen length of server address
+ * @param addrlen length of @a serv_addr
  * @return the connection handle
  */
 struct GNUNET_CONNECTION_Handle *
-GNUNET_CONNECTION_create_from_sockaddr (int af_family,
-                                        const struct sockaddr *serv_addr,
-                                        socklen_t addrlen)
+GNUNET_CONNECTION_connect_socket (struct GNUNET_NETWORK_Handle *s,
+                                  const struct sockaddr *serv_addr,
+                                  socklen_t addrlen)
 {
-  struct GNUNET_NETWORK_Handle *s;
   struct GNUNET_CONNECTION_Handle *connection;
 
-  s = GNUNET_NETWORK_socket_create (af_family, SOCK_STREAM, 0);
-  if (NULL == s)
-  {
-    LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING | GNUNET_ERROR_TYPE_BULK, "socket");
-    return NULL;
-  }
-  if ((GNUNET_OK != GNUNET_NETWORK_socket_connect (s, serv_addr, addrlen)) &&
-      (EINPROGRESS != errno))
+  if ( (GNUNET_OK !=
+        GNUNET_NETWORK_socket_connect (s, serv_addr, addrlen)) &&
+       (EINPROGRESS != errno) )
   {
     /* maybe refused / unsupported address, try next */
-    LOG_STRERROR (GNUNET_ERROR_TYPE_INFO, "connect");
-    LOG (GNUNET_ERROR_TYPE_INFO, _("Attempt to connect to `%s' failed\n"),
-         GNUNET_a2s (serv_addr, addrlen));
+    LOG_STRERROR (GNUNET_ERROR_TYPE_DEBUG,
+                  "connect");
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Attempt to connect to `%s' failed\n",
+         GNUNET_a2s (serv_addr,
+                     addrlen));
     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (s));
     return NULL;
   }
   connection = GNUNET_CONNECTION_create_from_existing (s);
   connection->addr = GNUNET_malloc (addrlen);
-  memcpy (connection->addr, serv_addr, addrlen);
+  GNUNET_memcpy (connection->addr, serv_addr, addrlen);
   connection->addrlen = addrlen;
-  LOG (GNUNET_ERROR_TYPE_INFO, _("Trying to connect to `%s' (%p)\n"),
-       GNUNET_a2s (serv_addr, addrlen), connection);
+  LOG (GNUNET_ERROR_TYPE_INFO,
+       "Trying to connect to `%s' (%p)\n",
+       GNUNET_a2s (serv_addr, addrlen),
+       connection);
   return connection;
 }
 
 
+/**
+ * Create a connection handle by creating a socket and
+ * (asynchronously) connecting to a host.  This function returns
+ * immediately, even if the connection has not yet been established.
+ * This function only creates TCP connections.
+ *
+ * @param af_family address family to use
+ * @param serv_addr server address
+ * @param addrlen length of @a serv_addr
+ * @return the connection handle
+ */
+struct GNUNET_CONNECTION_Handle *
+GNUNET_CONNECTION_create_from_sockaddr (int af_family,
+                                        const struct sockaddr *serv_addr,
+                                        socklen_t addrlen)
+{
+  struct GNUNET_NETWORK_Handle *s;
+
+  s = GNUNET_NETWORK_socket_create (af_family, SOCK_STREAM, 0);
+  if (NULL == s)
+  {
+    LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING | GNUNET_ERROR_TYPE_BULK,
+                 "socket");
+    return NULL;
+  }
+  return GNUNET_CONNECTION_connect_socket (s,
+                                          serv_addr,
+                                          addrlen);
+}
+
+
 /**
  * Check if connection is valid (no fatal errors have happened so far).
  * Note that a connection that is still trying to connect is considered
  * valid.
  *
  * @param connection connection to check
- * @return GNUNET_YES if valid, GNUNET_NO otherwise
+ * @return #GNUNET_YES if valid, #GNUNET_NO otherwise
  */
 int
 GNUNET_CONNECTION_check (struct GNUNET_CONNECTION_Handle *connection)
 {
-  if ((NULL != connection->ap_head) || (NULL != connection->dns_active))
+  if ((NULL != connection->ap_head) ||
+      (NULL != connection->dns_active) ||
+      (NULL != connection->proxy_handshake))
     return GNUNET_YES;          /* still trying to connect */
-  return (NULL == connection->sock) ? GNUNET_NO : GNUNET_YES;
+  if ( (0 != connection->destroy_later) ||
+       (NULL == connection->sock) )
+    return GNUNET_NO;
+  return GNUNET_YES;
 }
 
 
@@ -954,24 +1059,26 @@ GNUNET_CONNECTION_destroy (struct GNUNET_CONNECTION_Handle *connection)
     connection->destroy_later = -1;
     return;
   }
-  LOG (GNUNET_ERROR_TYPE_DEBUG, "Shutting down connection (%p)\n", connection);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Shutting down connection (%p)\n",
+       connection);
   GNUNET_assert (NULL == connection->nth.notify_ready);
   GNUNET_assert (NULL == connection->receiver);
-  if (GNUNET_SCHEDULER_NO_TASK != connection->write_task)
+  if (NULL != connection->write_task)
   {
     GNUNET_SCHEDULER_cancel (connection->write_task);
-    connection->write_task = GNUNET_SCHEDULER_NO_TASK;
+    connection->write_task = NULL;
     connection->write_buffer_off = 0;
   }
-  if (GNUNET_SCHEDULER_NO_TASK != connection->read_task)
+  if (NULL != connection->read_task)
   {
     GNUNET_SCHEDULER_cancel (connection->read_task);
-    connection->read_task = GNUNET_SCHEDULER_NO_TASK;
+    connection->read_task = NULL;
   }
-  if (GNUNET_SCHEDULER_NO_TASK != connection->nth.timeout_task)
+  if (NULL != connection->nth.timeout_task)
   {
     GNUNET_SCHEDULER_cancel (connection->nth.timeout_task);
-    connection->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
+    connection->nth.timeout_task = NULL;
   }
   connection->nth.notify_ready = NULL;
   if (NULL != connection->dns_active)
@@ -979,25 +1086,39 @@ GNUNET_CONNECTION_destroy (struct GNUNET_CONNECTION_Handle *connection)
     GNUNET_RESOLVER_request_cancel (connection->dns_active);
     connection->dns_active = NULL;
   }
+  if (NULL != connection->proxy_handshake)
+  {
+    /* GNUNET_CONNECTION_destroy (connection->proxy_handshake); */
+    connection->proxy_handshake->destroy_later = -1;
+    connection->proxy_handshake = NULL;  /* Not leaked ??? */
+  }
   while (NULL != (pos = connection->ap_head))
   {
     GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pos->sock));
     GNUNET_SCHEDULER_cancel (pos->task);
-    GNUNET_CONTAINER_DLL_remove (connection->ap_head, connection->ap_tail, pos);
+    GNUNET_CONTAINER_DLL_remove (connection->ap_head,
+                                connection->ap_tail,
+                                pos);
     GNUNET_free (pos);
   }
   if ( (NULL != connection->sock) &&
        (GNUNET_YES != connection->persist) )
   {
-    if ((GNUNET_YES != GNUNET_NETWORK_socket_shutdown (connection->sock, SHUT_RDWR)) && 
-       (ENOTCONN != errno) && 
+    if ((GNUNET_OK !=
+         GNUNET_NETWORK_socket_shutdown (connection->sock,
+                                         SHUT_RDWR)) &&
+       (ENOTCONN != errno) &&
        (ECONNRESET != errno) )
-      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "shutdown");    
+      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING,
+                    "shutdown");
   }
   if (NULL != connection->sock)
   {
     if (GNUNET_YES != connection->persist)
-      GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (connection->sock));
+    {
+      GNUNET_break (GNUNET_OK ==
+                    GNUNET_NETWORK_socket_close (connection->sock));
+    }
     else
     {
       GNUNET_NETWORK_socket_free_memory_only_ (connection->sock); /* at least no memory leak (we deliberately
@@ -1016,32 +1137,26 @@ GNUNET_CONNECTION_destroy (struct GNUNET_CONNECTION_Handle *connection)
  * or have data ready to read.
  *
  * @param cls connection to read from
- * @param tc scheduler context
  */
 static void
-receive_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+receive_ready (void *cls)
 {
   struct GNUNET_CONNECTION_Handle *connection = cls;
+  const struct GNUNET_SCHEDULER_TaskContext *tc;
   char buffer[connection->max];
   ssize_t ret;
   GNUNET_CONNECTION_Receiver receiver;
 
-  connection->read_task = GNUNET_SCHEDULER_NO_TASK;
-  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
-  {
-    /* ignore shutdown request, go again immediately */
-    connection->read_task =
-        GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining
-                                       (connection->receive_timeout), connection->sock,
-                                       &receive_ready, connection);
-    return;
-  }
+  connection->read_task = NULL;
+  tc = GNUNET_SCHEDULER_get_task_context ();
   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Receive from `%s' encounters error: timeout (%s, %p)\n",
-        GNUNET_a2s (connection->addr, connection->addrlen),
-        GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (connection->receive_timeout), GNUNET_YES),
+        GNUNET_a2s (connection->addr,
+                    connection->addrlen),
+        GNUNET_STRINGS_relative_time_to_string (GNUNET_TIME_absolute_get_duration (connection->receive_timeout),
+                                                GNUNET_YES),
         connection);
     signal_receive_timeout (connection);
     return;
@@ -1052,9 +1167,12 @@ receive_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
     signal_receive_error (connection, ECONNREFUSED);
     return;
   }
-  GNUNET_assert (GNUNET_NETWORK_fdset_isset (tc->read_ready, connection->sock));
+  GNUNET_assert (GNUNET_NETWORK_fdset_isset (tc->read_ready,
+                                            connection->sock));
 RETRY:
-  ret = GNUNET_NETWORK_socket_recv (connection->sock, buffer, connection->max);
+  ret = GNUNET_NETWORK_socket_recv (connection->sock,
+                                    buffer,
+                                    connection->max);
   if (-1 == ret)
   {
     if (EINTR == errno)
@@ -1063,17 +1181,26 @@ RETRY:
     return;
   }
   LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "receive_ready read %u/%u bytes from `%s' (%p)!\n", (unsigned int) ret,
-       connection->max, GNUNET_a2s (connection->addr, connection->addrlen), connection);
+       "receive_ready read %u/%u bytes from `%s' (%p)!\n",
+       (unsigned int) ret,
+       connection->max,
+       GNUNET_a2s (connection->addr,
+                   connection->addrlen),
+       connection);
   GNUNET_assert (NULL != (receiver = connection->receiver));
   connection->receiver = NULL;
-  receiver (connection->receiver_cls, buffer, ret, connection->addr, connection->addrlen, 0);
+  receiver (connection->receiver_cls,
+            buffer,
+            ret,
+            connection->addr,
+            connection->addrlen,
+            0);
 }
 
 
 /**
- * Receive data from the given connection.  Note that this function will
- * call "receiver" asynchronously using the scheduler.  It will
+ * Receive data from the given connection.  Note that this function
+ * will call @a receiver asynchronously using the scheduler.  It will
  * "immediately" return.  Note that there MUST only be one active
  * receive call per connection at any given point in time (so do not
  * call receive again until the receiver callback has been invoked).
@@ -1082,15 +1209,16 @@ RETRY:
  * @param max maximum number of bytes to read
  * @param timeout maximum amount of time to wait
  * @param receiver function to call with received data
- * @param receiver_cls closure for receiver
+ * @param receiver_cls closure for @a receiver
  */
 void
-GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *connection, size_t max,
+GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *connection,
+                           size_t max,
                            struct GNUNET_TIME_Relative timeout,
                            GNUNET_CONNECTION_Receiver receiver,
                            void *receiver_cls)
 {
-  GNUNET_assert ((GNUNET_SCHEDULER_NO_TASK == connection->read_task) &&
+  GNUNET_assert ((NULL == connection->read_task) &&
                  (NULL == connection->receiver));
   GNUNET_assert (NULL != receiver);
   connection->receiver = receiver;
@@ -1101,14 +1229,21 @@ GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *connection, size_t m
   {
     connection->read_task =
       GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining
-                                     (connection->receive_timeout), connection->sock,
-                                     &receive_ready, connection);
+                                     (connection->receive_timeout),
+                                     connection->sock,
+                                     &receive_ready,
+                                     connection);
     return;
   }
-  if ((NULL == connection->dns_active) && (NULL == connection->ap_head))
+  if ((NULL == connection->dns_active) &&
+      (NULL == connection->ap_head) &&
+      (NULL == connection->proxy_handshake))
   {
     connection->receiver = NULL;
-    receiver (receiver_cls, NULL, 0, NULL, 0, ETIMEDOUT);
+    receiver (receiver_cls,
+             NULL, 0,
+             NULL, 0,
+             ETIMEDOUT);
     return;
   }
 }
@@ -1125,10 +1260,11 @@ GNUNET_CONNECTION_receive (struct GNUNET_CONNECTION_Handle *connection, size_t m
 void *
 GNUNET_CONNECTION_receive_cancel (struct GNUNET_CONNECTION_Handle *connection)
 {
-  if (GNUNET_SCHEDULER_NO_TASK != connection->read_task)
+  if (NULL != connection->read_task)
   {
-    GNUNET_assert (connection == GNUNET_SCHEDULER_cancel (connection->read_task));
-    connection->read_task = GNUNET_SCHEDULER_NO_TASK;
+    GNUNET_assert (connection ==
+                   GNUNET_SCHEDULER_cancel (connection->read_task));
+    connection->read_task = NULL;
   }
   connection->receiver = NULL;
   return connection->receiver_cls;
@@ -1140,7 +1276,7 @@ GNUNET_CONNECTION_receive_cancel (struct GNUNET_CONNECTION_Handle *connection)
  * have enough space available first)!
  *
  * @param connection connection for which we should do this processing
- * @return GNUNET_YES if we were able to call notify
+ * @return #GNUNET_YES if we were able to call notify
  */
 static int
 process_notify (struct GNUNET_CONNECTION_Handle *connection)
@@ -1150,12 +1286,13 @@ process_notify (struct GNUNET_CONNECTION_Handle *connection)
   size_t size;
   GNUNET_CONNECTION_TransmitReadyNotify notify;
 
-  LOG (GNUNET_ERROR_TYPE_DEBUG, "process_notify is running\n");
-
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == connection->write_task);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "process_notify is running\n");
+  GNUNET_assert (NULL == connection->write_task);
   if (NULL == (notify = connection->nth.notify_ready))
   {
-    LOG (GNUNET_ERROR_TYPE_DEBUG, "Noone to notify\n");
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "No one to notify\n");
     return GNUNET_NO;
   }
   used = connection->write_buffer_off - connection->write_buffer_pos;
@@ -1163,14 +1300,16 @@ process_notify (struct GNUNET_CONNECTION_Handle *connection)
   size = connection->nth.notify_size;
   if (size > avail)
   {
-    LOG (GNUNET_ERROR_TYPE_DEBUG, "Not enough buffer\n");
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Not enough buffer\n");
     return GNUNET_NO;
   }
   connection->nth.notify_ready = NULL;
   if (connection->write_buffer_size - connection->write_buffer_off < size)
   {
     /* need to compact */
-    memmove (connection->write_buffer, &connection->write_buffer[connection->write_buffer_pos],
+    memmove (connection->write_buffer,
+             &connection->write_buffer[connection->write_buffer_pos],
              used);
     connection->write_buffer_off -= connection->write_buffer_pos;
     connection->write_buffer_pos = 0;
@@ -1195,24 +1334,28 @@ process_notify (struct GNUNET_CONNECTION_Handle *connection)
  *
  * This task notifies the client about the timeout.
  *
- * @param cls the 'struct GNUNET_CONNECTION_Handle'
- * @param tc scheduler context
+ * @param cls the `struct GNUNET_CONNECTION_Handle`
  */
 static void
-transmit_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+transmit_timeout (void *cls)
 {
   struct GNUNET_CONNECTION_Handle *connection = cls;
   GNUNET_CONNECTION_TransmitReadyNotify notify;
 
-  connection->nth.timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  connection->nth.timeout_task = NULL;
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Transmit to `%s:%u/%s' fails, time out reached (%p).\n",
        connection->hostname,
-       connection->port, GNUNET_a2s (connection->addr, connection->addrlen), connection);
+       connection->port,
+       GNUNET_a2s (connection->addr,
+                   connection->addrlen),
+       connection);
   notify = connection->nth.notify_ready;
   GNUNET_assert (NULL != notify);
   connection->nth.notify_ready = NULL;
-  notify (connection->nth.notify_ready_cls, 0, NULL);
+  notify (connection->nth.notify_ready_cls,
+         0,
+         NULL);
 }
 
 
@@ -1222,22 +1365,26 @@ transmit_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  *
  * This task notifies the client about the error.
  *
- * @param cls the 'struct GNUNET_CONNECTION_Handle'
- * @param tc scheduler context
+ * @param cls the `struct GNUNET_CONNECTION_Handle`
  */
 static void
-connect_error (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+connect_error (void *cls)
 {
   struct GNUNET_CONNECTION_Handle *connection = cls;
   GNUNET_CONNECTION_TransmitReadyNotify notify;
 
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Transmission request of size %u fails (%s/%u), connection failed (%p).\n",
-       connection->nth.notify_size, connection->hostname, connection->port, connection);
-  connection->write_task = GNUNET_SCHEDULER_NO_TASK;
+       connection->nth.notify_size,
+       connection->hostname,
+       connection->port,
+       connection);
+  connection->write_task = NULL;
   notify = connection->nth.notify_ready;
   connection->nth.notify_ready = NULL;
-  notify (connection->nth.notify_ready_cls, 0, NULL);
+  notify (connection->nth.notify_ready_cls,
+         0,
+         NULL);
 }
 
 
@@ -1245,40 +1392,30 @@ connect_error (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  * We are ready to transmit (or got a timeout).
  *
  * @param cls our connection handle
- * @param tc task context describing why we are here
  */
 static void
-transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+transmit_ready (void *cls)
 {
   struct GNUNET_CONNECTION_Handle *connection = cls;
   GNUNET_CONNECTION_TransmitReadyNotify notify;
+  const struct GNUNET_SCHEDULER_TaskContext *tc;
   ssize_t ret;
   size_t have;
 
-  LOG (GNUNET_ERROR_TYPE_DEBUG, "transmit_ready running (%p).\n", connection);
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != connection->write_task);
-  connection->write_task = GNUNET_SCHEDULER_NO_TASK;
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == connection->nth.timeout_task);
-  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
-  {
-    if (NULL != connection->sock)
-      goto SCHEDULE_WRITE;      /* ignore shutdown, go again immediately */
-    LOG (GNUNET_ERROR_TYPE_DEBUG,
-         "Transmit to `%s' fails, shutdown happened (%p).\n",
-         GNUNET_a2s (connection->addr, connection->addrlen), connection);
-    notify = connection->nth.notify_ready;
-    if (NULL != notify)
-    {
-      connection->nth.notify_ready = NULL;
-      notify (connection->nth.notify_ready_cls, 0, NULL);
-    }
-    return;
-  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "transmit_ready running (%p).\n",
+       connection);
+  GNUNET_assert (NULL != connection->write_task);
+  connection->write_task = NULL;
+  GNUNET_assert (NULL == connection->nth.timeout_task);
+  tc = GNUNET_SCHEDULER_get_task_context ();
   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_TIMEOUT))
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
          "Transmit to `%s' fails, time out reached (%p).\n",
-         GNUNET_a2s (connection->addr, connection->addrlen), connection);
+         GNUNET_a2s (connection->addr,
+                     connection->addrlen),
+         connection);
     notify = connection->nth.notify_ready;
     GNUNET_assert (NULL != notify);
     connection->nth.notify_ready = NULL;
@@ -1286,16 +1423,17 @@ transmit_ready (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
     return;
   }
   GNUNET_assert (NULL != connection->sock);
-  if (NULL == tc->write_ready) 
+  if (NULL == tc->write_ready)
   {
     /* special circumstances (in particular, PREREQ_DONE after
      * connect): not yet ready to write, but no "fatal" error either.
      * Hence retry.  */
     goto SCHEDULE_WRITE;
   }
-  if (!GNUNET_NETWORK_fdset_isset (tc->write_ready, connection->sock))
+  if (! GNUNET_NETWORK_fdset_isset (tc->write_ready,
+                                   connection->sock))
   {
-    GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == connection->write_task);
+    GNUNET_assert (NULL == connection->write_task);
     /* special circumstances (in particular, shutdown): not yet ready
      * to write, but no "fatal" error either.  Hence retry.  */
     goto SCHEDULE_WRITE;
@@ -1327,17 +1465,21 @@ RETRY:
   {
     if (EINTR == errno)
       goto RETRY;
-    if (GNUNET_SCHEDULER_NO_TASK != connection->write_task)
+    if (NULL != connection->write_task)
     {
       GNUNET_SCHEDULER_cancel (connection->write_task);
-      connection->write_task = GNUNET_SCHEDULER_NO_TASK;
+      connection->write_task = NULL;
     }
     signal_transmit_error (connection, errno);
     return;
   }
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Connection transmitted %u/%u bytes to `%s' (%p)\n",
-       (unsigned int) ret, have, GNUNET_a2s (connection->addr, connection->addrlen), connection);
+       (unsigned int) ret,
+       have,
+       GNUNET_a2s (connection->addr,
+                  connection->addrlen),
+       connection);
   connection->write_buffer_pos += ret;
   if (connection->write_buffer_pos == connection->write_buffer_off)
   {
@@ -1345,35 +1487,39 @@ RETRY:
     connection->write_buffer_pos = 0;
     connection->write_buffer_off = 0;
   }
-  if ((0 == connection->write_buffer_off) && (NULL == connection->nth.notify_ready))
+  if ( (0 == connection->write_buffer_off) &&
+       (NULL == connection->nth.notify_ready) )
     return;                     /* all data sent! */
   /* not done writing, schedule more */
 SCHEDULE_WRITE:
   LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Re-scheduling transmit_ready (more to do) (%p).\n", connection);
+       "Re-scheduling transmit_ready (more to do) (%p).\n",
+       connection);
   have = connection->write_buffer_off - connection->write_buffer_pos;
-  GNUNET_assert ((NULL != connection->nth.notify_ready) || (have > 0));
-  if (GNUNET_SCHEDULER_NO_TASK == connection->write_task)
+  GNUNET_assert ( (NULL != connection->nth.notify_ready) ||
+                 (have > 0) );
+  if (NULL == connection->write_task)
     connection->write_task =
         GNUNET_SCHEDULER_add_write_net ((connection->nth.notify_ready ==
                                          NULL) ? GNUNET_TIME_UNIT_FOREVER_REL :
                                         GNUNET_TIME_absolute_get_remaining
                                         (connection->nth.transmit_timeout),
-                                        connection->sock, &transmit_ready, connection);
+                                        connection->sock,
+                                       &transmit_ready, connection);
 }
 
 
 /**
  * Ask the connection to call us once the specified number of bytes
- * are free in the transmission buffer.  May call the notify
- * method immediately if enough space is available.
+ * are free in the transmission buffer.  Will never call the @a notify
+ * callback in this task, but always first go into the scheduler.
  *
  * @param connection connection
  * @param size number of bytes to send
  * @param timeout after how long should we give up (and call
- *        notify with buf NULL and size 0)?
+ *        @a notify with buf NULL and size 0)?
  * @param notify function to call
- * @param notify_cls closure for notify
+ * @param notify_cls closure for @a notify
  * @return non-NULL if the notify callback was queued,
  *         NULL if we are already going to notify someone else (busy)
  */
@@ -1381,8 +1527,8 @@ struct GNUNET_CONNECTION_TransmitHandle *
 GNUNET_CONNECTION_notify_transmit_ready (struct GNUNET_CONNECTION_Handle *connection,
                                          size_t size,
                                          struct GNUNET_TIME_Relative timeout,
-                                         GNUNET_CONNECTION_TransmitReadyNotify
-                                         notify, void *notify_cls)
+                                         GNUNET_CONNECTION_TransmitReadyNotify notify,
+                                        void *notify_cls)
 {
   if (NULL != connection->nth.notify_ready)
   {
@@ -1399,33 +1545,41 @@ GNUNET_CONNECTION_notify_transmit_ready (struct GNUNET_CONNECTION_Handle *connec
   connection->nth.connection = connection;
   connection->nth.notify_size = size;
   connection->nth.transmit_timeout = GNUNET_TIME_relative_to_absolute (timeout);
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == connection->nth.timeout_task);
-  if ((NULL == connection->sock) && 
+  GNUNET_assert (NULL == connection->nth.timeout_task);
+  if ((NULL == connection->sock) &&
       (NULL == connection->ap_head) &&
-      (NULL == connection->dns_active))
+      (NULL == connection->dns_active) &&
+      (NULL == connection->proxy_handshake))
   {
-    if (GNUNET_SCHEDULER_NO_TASK != connection->write_task)
+    if (NULL != connection->write_task)
       GNUNET_SCHEDULER_cancel (connection->write_task);
-    connection->write_task = GNUNET_SCHEDULER_add_now (&connect_error, connection);
+    connection->write_task = GNUNET_SCHEDULER_add_now (&connect_error,
+                                                       connection);
     return &connection->nth;
   }
-  if (GNUNET_SCHEDULER_NO_TASK != connection->write_task)
+  if (NULL != connection->write_task)
     return &connection->nth; /* previous transmission still in progress */
   if (NULL != connection->sock)
   {
     /* connected, try to transmit now */
-    LOG (GNUNET_ERROR_TYPE_DEBUG, "Scheduling transmission (%p).\n", connection);
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Scheduling transmission (%p).\n",
+         connection);
     connection->write_task =
         GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_absolute_get_remaining
                                         (connection->nth.transmit_timeout),
-                                        connection->sock, &transmit_ready, connection);
+                                        connection->sock,
+                                       &transmit_ready, connection);
     return &connection->nth;
   }
   /* not yet connected, wait for connection */
   LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Need to wait to schedule transmission for connection, adding timeout task (%p).\n", connection);
+       "Need to wait to schedule transmission for connection, adding timeout task (%p).\n",
+       connection);
   connection->nth.timeout_task =
-    GNUNET_SCHEDULER_add_delayed (timeout, &transmit_timeout, connection);
+    GNUNET_SCHEDULER_add_delayed (timeout,
+                                  &transmit_timeout,
+                                 connection);
   return &connection->nth;
 }
 
@@ -1436,22 +1590,59 @@ GNUNET_CONNECTION_notify_transmit_ready (struct GNUNET_CONNECTION_Handle *connec
  * @param th notification to cancel
  */
 void
-GNUNET_CONNECTION_notify_transmit_ready_cancel (struct
-                                                GNUNET_CONNECTION_TransmitHandle
-                                                *th)
+GNUNET_CONNECTION_notify_transmit_ready_cancel (struct GNUNET_CONNECTION_TransmitHandle *th)
 {
   GNUNET_assert (NULL != th->notify_ready);
   th->notify_ready = NULL;
-  if (GNUNET_SCHEDULER_NO_TASK != th->timeout_task)
+  if (NULL != th->timeout_task)
   {
     GNUNET_SCHEDULER_cancel (th->timeout_task);
-    th->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+    th->timeout_task = NULL;
   }
-  if (GNUNET_SCHEDULER_NO_TASK != th->connection->write_task)
+  if (NULL != th->connection->write_task)
   {
     GNUNET_SCHEDULER_cancel (th->connection->write_task);
-    th->connection->write_task = GNUNET_SCHEDULER_NO_TASK;
+    th->connection->write_task = NULL;
   }
 }
 
+
+/**
+ * Create a connection to be proxied using a given connection.
+ *
+ * @param cph connection to proxy server
+ * @return connection to be proxied
+ */
+struct GNUNET_CONNECTION_Handle *
+GNUNET_CONNECTION_create_proxied_from_handshake (struct GNUNET_CONNECTION_Handle *cph)
+{
+  struct GNUNET_CONNECTION_Handle *proxied = GNUNET_CONNECTION_create_from_existing (NULL);
+
+  proxied->proxy_handshake = cph;
+  return proxied;
+}
+
+
+/**
+ * Activate proxied connection and destroy initial proxy handshake connection.
+ * There must not be any pending requests for reading or writing to the
+ * proxy hadshake connection at this time.
+ *
+ * @param proxied connection connection to proxy server
+ */
+void
+GNUNET_CONNECTION_acivate_proxied (struct GNUNET_CONNECTION_Handle *proxied)
+{
+  struct GNUNET_CONNECTION_Handle *cph = proxied->proxy_handshake;
+
+  GNUNET_assert (NULL != cph);
+  GNUNET_assert (NULL == proxied->sock);
+  GNUNET_assert (NULL != cph->sock);
+  proxied->sock = cph->sock;
+  cph->sock = NULL;
+  GNUNET_CONNECTION_destroy (cph);
+  connect_success_continuation (proxied);
+}
+
+
 /* end of connection.c */