first quick hack to extract an initial DNS service API

1 files changed, 263 insertions, 0 deletions

diff --git a/src/dns/dns_api.c b/src/dns/dns_api.c
new file mode 100644
index 0000000000..90b4a8f42f
--- /dev/null
+++ b/src/dns/dns_api.c
@@ -0,0 +1,263 @@
+/*
+     This file is part of GNUnet.
+     (C) 2010 Christian Grothoff
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 3, or (at your
+     option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     General Public License for more details.
+
+     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.
+*/
+
+/**
+ * @file vpn/gnunet-daemon-vpn-dns.c
+ * @brief
+ * @author Philipp Toelke
+ */
+#include <platform.h>
+#include <gnunet_common.h>
+#include <gnunet_client_lib.h>
+#include <gnunet_os_lib.h>
+#include <gnunet_mesh_service.h>
+#include <gnunet_protocols.h>
+#include <gnunet_server_lib.h>
+#include <gnunet_container_lib.h>
+#include <block_dns.h>
+
+#include "gnunet_dns_service.h"
+
+
+struct GNUNET_DNS_Handle
+{
+  struct query_packet_list *head;
+  struct query_packet_list *tail;
+  struct GNUNET_CLIENT_Connection *dns_connection;
+  unsigned char restart_hijack;
+
+  struct GNUNET_CLIENT_TransmitHandle *dns_transmit_handle;
+
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  GNUNET_SCHEDULER_Task process_answer_cb;
+  
+  void *process_answer_cb_cls;
+};
+
+
+/**
+ * Callback called by notify_transmit_ready; sends dns-queries or rehijack-messages
+ * to the service-dns
+ * {{{
+ */
+size_t
+send_query (void *cls GNUNET_UNUSED, size_t size, void *buf)
+{
+  struct GNUNET_DNS_Handle *h = cls;
+
+  size_t len;
+
+  h->dns_transmit_handle = NULL;
+
+  /*
+   * Send the rehijack-message
+   */
+  if (h->restart_hijack == 1)
+  {
+    h->restart_hijack = 0;
+    /*
+     * The message is just a header
+     */
+    GNUNET_assert (sizeof (struct GNUNET_MessageHeader) <= size);
+    struct GNUNET_MessageHeader *hdr = buf;
+
+    len = sizeof (struct GNUNET_MessageHeader);
+    hdr->size = htons (len);
+    hdr->type = htons (GNUNET_MESSAGE_TYPE_REHIJACK);
+  }
+  else if (h->head != NULL)
+  {
+    struct query_packet_list *query = h->head;
+
+    len = ntohs (query->pkt.hdr.size);
+
+    GNUNET_assert (len <= size);
+
+    memcpy (buf, &query->pkt.hdr, len);
+
+    GNUNET_CONTAINER_DLL_remove (h->head, h->tail, query);
+
+    GNUNET_free (query);
+  }
+  else
+  {
+    GNUNET_break (0);
+    len = 0;
+  }
+
+  /*
+   * Check whether more data is to be sent
+   */
+  if (h->head != NULL)
+  {
+    h->dns_transmit_handle =
+      GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
+					   ntohs (h->head->pkt.hdr.size),
+                                             GNUNET_TIME_UNIT_FOREVER_REL,
+                                             GNUNET_YES, &send_query, h);
+  }
+  else if (h->restart_hijack == 1)
+  {
+    h->dns_transmit_handle =
+      GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
+					   sizeof (struct
+                                                     GNUNET_MessageHeader),
+                                             GNUNET_TIME_UNIT_FOREVER_REL,
+                                             GNUNET_YES, &send_query, h);
+  }
+
+  return len;
+}
+
+/* }}} */
+
+
+
+/**
+ * This receives packets from the service-dns and schedules process_answer to
+ * handle it
+ */
+static void
+dns_answer_handler (void *cls,
+                    const struct GNUNET_MessageHeader *msg)
+{
+  struct GNUNET_DNS_Handle *h = cls;
+
+  /* the service disconnected, reconnect after short wait */
+  if (msg == NULL)
+  {
+    if (h->dns_transmit_handle != NULL)
+      GNUNET_CLIENT_notify_transmit_ready_cancel (h->dns_transmit_handle);
+    h->dns_transmit_handle = NULL;
+    GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO);
+    h->dns_connection = NULL;
+#if 0
+    h->conn_task =
+        GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
+                                      &connect_to_service_dns, h);
+#endif
+    return;
+  }
+
+  /* the service did something strange, reconnect immediately */
+  if (msg->type != htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS))
+  {
+    GNUNET_break (0);
+    GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO);
+    h->dns_connection = NULL;
+#if 0
+    conn_task = GNUNET_SCHEDULER_add_now (&connect_to_service_dns, NULL);
+#endif
+    return;
+  }
+  void *pkt = GNUNET_malloc (ntohs (msg->size));
+
+  memcpy (pkt, msg, ntohs (msg->size));
+
+  GNUNET_SCHEDULER_add_now (h->process_answer_cb, pkt);
+  GNUNET_CLIENT_receive (h->dns_connection, &dns_answer_handler, h,
+                         GNUNET_TIME_UNIT_FOREVER_REL);
+}
+
+
+/**
+ * Connect to the service-dns
+ */
+struct GNUNET_DNS_Handle *
+GNUNET_DNS_connect (const struct GNUNET_CONFIGURATION_Handle *cfg,
+		    GNUNET_SCHEDULER_Task cb,
+		    void *cb_cls)
+{
+  struct GNUNET_DNS_Handle *h;
+
+  h = GNUNET_malloc (sizeof (struct GNUNET_DNS_Handle));
+  h->cfg = cfg;
+  h->process_answer_cb = cb;
+  h->process_answer_cb_cls = cb_cls;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connecting to service-dns\n");
+  h->dns_connection = GNUNET_CLIENT_connect ("dns", h->cfg);
+  /* This would most likely be a misconfiguration */
+  GNUNET_assert (NULL != h->dns_connection);
+  GNUNET_CLIENT_receive (h->dns_connection, 
+			 &dns_answer_handler, NULL,
+                         GNUNET_TIME_UNIT_FOREVER_REL);
+  /* If a packet is already in the list, schedule to send it */
+  if (h->dns_transmit_handle == NULL && h->head != NULL)
+    h->dns_transmit_handle =
+        GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
+                                             ntohs (h->head->pkt.hdr.size),
+                                             GNUNET_TIME_UNIT_FOREVER_REL,
+                                             GNUNET_YES, &send_query, h);
+  else if (h->dns_transmit_handle == NULL && h->restart_hijack == 1)
+  {
+    h->dns_transmit_handle =
+      GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
+					   sizeof (struct
+                                                     GNUNET_MessageHeader),
+                                             GNUNET_TIME_UNIT_FOREVER_REL,
+                                             GNUNET_YES, &send_query, NULL);
+  }
+  return h;
+}
+
+
+void
+GNUNET_DNS_restart_hijack (struct GNUNET_DNS_Handle *h)
+{
+  h->restart_hijack = 1;
+  if (NULL != h->dns_connection && h->dns_transmit_handle == NULL)
+    h->dns_transmit_handle =
+      GNUNET_CLIENT_notify_transmit_ready (h->dns_connection,
+                                             sizeof (struct
+                                                     GNUNET_MessageHeader),
+                                             GNUNET_TIME_UNIT_FOREVER_REL,
+                                             GNUNET_YES, &send_query, h);
+}
+
+
+/**
+ * FIXME: we should not expost our internal structures like this.
+ * Just a quick initial hack.
+ */
+void
+GNUNET_DNS_queue_request (struct GNUNET_DNS_Handle *h,
+			  struct query_packet_list *q)
+{
+  GNUNET_CONTAINER_DLL_insert_tail (h->head, h->tail, q);
+  if (h->dns_connection != NULL && h->dns_transmit_handle == NULL)
+    h->dns_transmit_handle =
+      GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, ntohs(q->pkt.hdr.size),
+					   GNUNET_TIME_UNIT_FOREVER_REL,
+					   GNUNET_YES, &send_query,
+					   h);
+}
+
+
+void
+GNUNET_DNS_disconnect (struct GNUNET_DNS_Handle *h)
+{
+  if (h->dns_connection != NULL)
+  {
+    GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO);
+    h->dns_connection = NULL;
+  }
+  GNUNET_free (h);
+}