[GNUnet-SVN] r18947 - gnunet/src/dns

[gnunet]

Author: grothoff
Date: 2012-01-02 16:24:49 +0100 (Mon, 02 Jan 2012)
New Revision: 18947

Added:
   gnunet/src/dns/gnunet-service-dns_new.c
Log:
-starting with new DNS service code

Added: gnunet/src/dns/gnunet-service-dns_new.c
===================================================================
--- gnunet/src/dns/gnunet-service-dns_new.c                             (rev 0)
+++ gnunet/src/dns/gnunet-service-dns_new.c     2012-01-02 15:24:49 UTC (rev 
18947)
@@ -0,0 +1,551 @@
+/*
+     This file is part of GNUnet.
+     (C) 2012 Christian Grothoff (and other contributing authors)
+
+     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 dns/gnunet-service-dns_new.c
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_constants.h"
+#include "gnunet_protocols.h"
+#include "gnunet_dnsparser_lib.h"
+#include "gnunet_signatures.h"
+#include "dns_new.h"
+
+
+/**
+ * Entry we keep for each active request.
+ */ 
+struct RequestRecord
+{
+
+
+  /**
+   * Entry of this request record in the heap (for fast removal).
+   */
+  struct GNUNET_CONTAINER_HeapNode *hentry;
+
+  /**
+   * Array of clients and their answers.
+   */ 
+  struct GNUNET_SERVER_Client *client;
+
+};
+
+
+/**
+ * Entry we keep for each client.
+ */ 
+struct ClientRecord
+{
+  /**
+   * Kept in doubly-linked list.
+   */ 
+  struct ClientRecord *next;
+
+  /**
+   * Kept in doubly-linked list.
+   */ 
+  struct ClientRecord *prev;
+
+  /**
+   * Handle to the client.
+   */ 
+  struct GNUNET_SERVER_Client *client;
+
+};
+
+
+/**
+ * The IPv4 UDP-Socket through which DNS-Resolves will be sent if they are not 
to be
+ * sent through gnunet. The port of this socket will not be hijacked.
+ */
+static struct GNUNET_NETWORK_Handle *dnsout4;
+
+/**
+ * The IPv6 UDP-Socket through which DNS-Resolves will be sent if they are not 
to be
+ * sent through gnunet. The port of this socket will not be hijacked.
+ */
+static struct GNUNET_NETWORK_Handle *dnsout6;
+
+/**
+ * Task for reading from dnsout4.
+ */
+static GNUNET_SCHEDULER_TaskIdentifier read4_task;
+
+/**
+ * Task for reading from dnsout6.
+ */
+static GNUNET_SCHEDULER_TaskIdentifier read6_task;
+
+/**
+ * The port bound to the socket dnsout (and/or dnsout6).  We always (try) to 
bind
+ * both sockets to the same port.
+ */
+static uint16_t dnsoutport;
+
+/**
+ * The configuration to use
+ */
+static const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+/**
+ * Handle to DNS hijacker helper process ("gnunet-helper-dns").
+ */
+static struct GNUNET_HELPER_Handle *hijacker;
+
+/**
+ * Command-line arguments we are giving to the hijacker process.
+ */
+static char *helper_argv[8];
+
+/**
+ * Head of DLL of clients we consult.
+ */
+static struct ClientRecord *clients_head;
+
+/**
+ * Tail of DLL of clients we consult.
+ */
+static struct ClientRecord *clients_tail;
+
+/**
+ * Hash map of open requests.
+ */
+static struct GNUNET_CONTAINER_MultiHashMap *request_map;
+
+/**
+ * Heap with open requests (sorted by time received, oldest on top).
+ */
+static struct GNUNET_CONTAINER_Heap *request_heap;
+
+
+
+/**
+ * Task run during shutdown.
+ *
+ * @param cls unused
+ * @param tc unused
+ */
+static void
+cleanup_task (void *cls GNUNET_UNUSED,
+              const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  unsigned int i;
+  struct RequestRecord *rr;
+
+  GNUNET_HELPER_stop (hijacker);
+  hijacker = NULL;
+  for (i=0;i<8;i++)
+    GNUNET_free_non_null (helper_argv[i]);
+  if (NULL != dnsout4)
+  {
+    GNUNET_NETWORK_socket_destroy (dnsout4);
+    dnsout4 = NULL;
+  }
+  if (GNUNET_SCHEDULER_NO_TASK != read4_task)
+  {
+    GNUNET_SCHEDULER_cancel (read4_task);
+    read4_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (NULL != dnsout6)
+  {
+    GNUNET_NETWORK_socket_destroy (dnsout6);
+    dnsout6 = NULL;
+  }
+  if (GNUNET_SCHEDULER_NO_TASK != read6_task)
+  {
+    GNUNET_SCHEDULER_cancel (read6_task);
+    read6_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (NULL != request_heap)
+  {
+    while (NULL != (rr = GNUNET_CONTAINER_heap_remove_root (request_heap)))
+    {
+      // FIXME: free rest of 'rr'
+      GNUNET_free (rr);
+    }
+    GNUNET_CONTAINER_heap_destroy (request_heap);
+    request_heap = NULL;
+  }
+  if (NULL != request_map)
+  {
+    GNUNET_CONTAINER_multihashmap_destroy (request_map);
+    request_map = NULL;
+  }
+}
+
+
+/**
+ * A client disconnected, clean up after it.
+ *
+ * @param cls unused
+ * @param client handle of client that disconnected
+ */ 
+static void
+client_disconnect (void *cls, struct GNUNET_SERVER_Client *client)
+{
+  struct ClientRecord *cr;
+
+  /* FIXME: clean up after client */
+  for (cr = clients_head; NULL != cr; cr = cr->next)
+  {
+    if (cr->client == client)
+    {
+      GNUNET_SERVER_client_drop (client);
+      GNUNET_CONTAINER_DLL_remove (clients_head,
+                                  clients_tail,
+                                  cr);
+      GNUNET_free (cr);
+      return;
+    }
+  }
+}
+
+
+/**
+ * Read a DNS response from the (unhindered) UDP-Socket
+ *
+ * @param cls socket to read from
+ * @param tc scheduler context (must be shutdown or read ready)
+ */
+static void
+read_response (void *cls,
+              const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_NETWORK_Handle *dnsout = cls;
+  struct sockaddr_in addr4;
+  struct sockaddr_in6 addr6;
+  struct sockaddr *addr;
+  socklen_t addrlen;
+  ssize_t r;
+  int len;
+
+  if (dnsout == dnsout4)
+  {
+    addrlen = sizeof (struct sockaddr_in);
+    addr = (struct sockaddr* ) &addr4;
+    read4_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, 
+                                               dnsout,
+                                               &read_response, 
+                                               dnsout);
+  }
+  else
+  {
+    addrlen = sizeof (struct sockaddr_in6);
+    addr = (struct sockaddr* ) &addr6;
+    read6_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, 
+                                               dnsout,
+                                               &read_response, 
+                                               dnsout);
+  }
+  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
+    return;
+
+#ifndef MINGW
+  if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout), FIONREAD, &len))
+  {
+    /* conservative choice: */
+    len = 65536;
+  }
+#else
+  /* port the code above? */
+  len = 65536;
+#endif
+
+  {
+    unsigned char buf[len];
+
+    memset (addr, 0, addrlen);  
+    r = GNUNET_NETWORK_socket_recvfrom (dnsout, 
+                                       buf, sizeof (buf),
+                                       addr, &addrlen);
+    if (-1 == r)
+    {
+      GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "recvfrom");
+      return;
+    }
+    // NOTE: struct dns_pkt *dns = (struct dns_pkt *) buf;
+    // FIXME: handle_response (buf, r, addr, addrlen);
+  }
+}
+
+
+/**
+ * Open source port for sending DNS request on IPv4.
+ *
+ * @return GNUNET_OK on success
+ */ 
+static int
+open_port4 ()
+{
+  struct sockaddr_in addr;
+  socklen_t addrlen;
+
+  dnsout4 = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
+  if (dnsout4 == NULL)
+    return GNUNET_SYSERR;
+
+  memset (&addr, 0, sizeof (struct sockaddr_in));
+  addr.sin_family = AF_INET;
+  int err = GNUNET_NETWORK_socket_bind (dnsout4,
+                                        (struct sockaddr *) &addr,
+                                        sizeof (struct sockaddr_in));
+
+  if (err != GNUNET_OK)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+               _("Could not bind to any port: %s\n"),
+               STRERROR (errno));
+    GNUNET_NETWORK_socket_destroy (dnsout4);
+    dnsout4 = NULL;
+    return GNUNET_SYSERR;
+  }
+
+  /* Read the port we bound to */
+  addrlen = sizeof (struct sockaddr_in);
+  if (0 != getsockname (GNUNET_NETWORK_get_fd (dnsout4), 
+                       (struct sockaddr *) &addr,
+                       &addrlen))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+               _("Could not determine port I got: %s\n"),
+               STRERROR (errno));
+    GNUNET_NETWORK_socket_destroy (dnsout4);
+    dnsout4 = NULL;
+    return GNUNET_SYSERR;
+  }
+  dnsoutport = htons (addr.sin_port);
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO, 
+             _("GNUnet DNS will exit on source port %u\n"),
+             (unsigned int) dnsoutport);
+  read4_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, 
+                                             dnsout,
+                                             &read_response, dnsout4);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Open source port for sending DNS request on IPv6.  Should be 
+ * called AFTER open_port4.
+ *
+ * @return GNUNET_OK on success
+ */ 
+static int
+open_port6 ()
+{
+  struct sockaddr_in6 addr;
+
+  dnsout6 = GNUNET_NETWORK_socket_create (AF_INET6, SOCK_DGRAM, 0);
+  if (dnsout6 == NULL)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+               _("Could not create IPv6 socket: %s\n"),
+               STRERROR (errno));
+    return GNUNET_SYSERR;
+  }
+  memset (&addr, 0, sizeof (struct sockaddr_in6));
+  addr.sin6_family = AF_INET6;
+  addr.sin6_port = htons (dnsoutport);
+  int err = GNUNET_NETWORK_socket_bind (dnsout6,
+                                        (struct sockaddr *) &addr,
+                                        sizeof (struct sockaddr_in6));
+
+  if (err != GNUNET_OK)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+               _("Could not bind to port %u: %s\n"),
+               (unsigned int) dnsoutport,
+               STRERROR (errno));
+    return GNUNET_SYSERR;
+  }
+  if (0 == dnsoutport)
+  {
+    addrlen = sizeof (struct sockaddr_in6);
+    if (0 != getsockname (GNUNET_NETWORK_get_fd (dnsout6), 
+                         (struct sockaddr *) &addr,
+                         &addrlen))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+                 _("Could not determine port I got: %s\n"),
+                 STRERROR (errno));
+      GNUNET_NETWORK_socket_destroy (dnsout6);
+      dnsout6 = NULL;
+      return GNUNET_SYSERR;
+    }
+  }
+  dnsoutport = htons (addr.sin6_port);
+  read6_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
+                                             dnsout6,
+                                             &read_response, dnsout6);
+  return GNUNET_YES;
+}
+
+
+/**
+ * We got a new client.  Make sure all new DNS requests pass by its desk.
+ *
+ * @param cls unused
+ * @param client the new client
+ * @param message the init message (unused)
+ */
+static void
+handle_client_init (void *cls GNUNET_UNUSED, 
+                   struct GNUNET_SERVER_Client *client,
+                   const struct GNUNET_MessageHeader *message GNUNET_UNUSED)
+{
+  struct ClientRecord *cr;
+
+  cr = GNUNET_malloc (sizeof (struct ClientRecord));
+  cr->client = client;
+  GNUNET_SERVER_client_keep (client);
+  GNUNET_CONTAINER_DLL_insert (clients_head,
+                              clients_tail,
+                              cr);
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+
+/**
+ * We got a response from a client.
+ *
+ * @param cls unused
+ * @param client the client
+ * @param message the response
+ */
+static void
+handle_client_response (void *cls GNUNET_UNUSED, 
+                       struct GNUNET_SERVER_Client *client,
+                       const struct GNUNET_MessageHeader *message 
GNUNET_UNUSED)
+{
+  // FIXME: validate and parse response, process response
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+
+/**
+ * Functions with this signature are called whenever a complete
+ * message is received by the tokenizer from the DNS hijack process.
+ *
+ * @param cls closure
+ * @param client identification of the client
+ * @param message the actual message, a DNS request we should handle
+ */
+static void
+process_helper_messages (void *cls, void *client,
+                        const struct GNUNET_MessageHeader *message)
+{
+  /* FIXME: parse message, create record, start processing! */
+  /* FIXME: put request into queue for clients / system DNS */
+}
+
+
+/**
+ * @param cls closure
+ * @param server the initialized server
+ * @param cfg_ configuration to use
+ */
+static void
+run (void *cls, struct GNUNET_SERVER_Handle *server,
+     const struct GNUNET_CONFIGURATION_Handle *cfg_)
+{
+  static const struct GNUNET_SERVER_MessageHandler handlers[] = {
+    /* callback, cls, type, size */
+    {&handle_client_init, NULL, GNUNET_MESSAGE_TYPE_DNS_CLIENT_INIT, sizeof 
(struct GNUNET_MessageHeader)},
+    {&handle_client_response, NULL, GNUNET_MESSAGE_TYPE_DNS_CLIENT_RESPONSE, 
0},
+    {NULL, NULL, 0, 0}
+  };
+  char port_s[6];
+  char *virt_dns;
+  struct GNUNET_OS_Process *proc;
+  char *ifc_name;
+  char *ipv4_addr;
+  char *ipv4_mask;
+  char *ipv6_addr;
+  char *ipv6_mask;
+
+  cfg = cfg_;
+  if (GNUNET_YES ==
+      GNUNET_CONFIGURATION_get_value_yesno (cfg_, "dns", "PROVIDE_EXIT"))
+  {
+    if ( (GNUNET_OK != open_port4 ()) &&
+        (GNUNET_OK != open_port6 ()) )
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                 _("Failed to open any port to provide DNS exit\n"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+  }
+
+  if (GNUNET_SYSERR ==
+      GNUNET_CONFIGURATION_get_value_string (cfg, "dns", "VIRTIFC", &ifc_name))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "No entry 'VIRTDNS' in configuration!\n");
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
+  /* FIXME: get all config options we need here! */
+  request_heap = GNUNET_CONTAINER_heap_create 
(GNUNET_CONTAINER_HEAP_ORDER_MIN);
+  request_map = GNUNET_CONTAINER_multihashmap_create (1024 * 16);
+  GNUNET_snprintf (port_s, 
+                  sizeof (port_s), 
+                  "%u", 
+                  (unsigned int) dnsoutport);
+  helper_argv[0] = GNUNET_strdup ("gnunet-dns");
+  helper_argv[1] = ifc_name;
+  helper_argv[2] = ipv6_addr;
+  helper_argv[3] = ipv6_mask;
+  helper_argv[4] = ipv4_addr;
+  helper_argv[5] = ipv4_mask;
+  helper_argv[6] = GNUNET_strdup (port_s);
+  helper_argv[7] = NULL;
+  hijacker = GNUNET_HELPER_start ("gnunet-helper-dns",
+                                 helper_argv,
+                                 &process_helper_messages,
+                                 NULL);
+  GNUNET_SERVER_add_handlers (server, handlers);
+  GNUNET_SERVER_disconnect_notify (server, &client_disconnect, NULL);
+  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleanup_task,
+                                cls);
+}
+
+
+/**
+ * The main function for the dns service.
+ *
+ * @param argc number of arguments from the command line
+ * @param argv command line arguments
+ * @return 0 ok, 1 on error
+ */
+int
+main (int argc, char *const *argv)
+{
+  return (GNUNET_OK ==
+          GNUNET_SERVICE_run (argc, argv, "dns", GNUNET_SERVICE_OPTION_NONE,
+                              &run, NULL)) ? 0 : 1;
+}
+
+
+/* end of gnunet-service-dns_new.c */