new NAT lib client api skeleton

1 files changed, 367 insertions, 0 deletions

diff --git a/src/nat/nat_api.c b/src/nat/nat_api.c
new file mode 100644
index 000000000..6488fdf88
--- /dev/null
+++ b/src/nat/nat_api.c
@@ -0,0 +1,367 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2007-2016 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
+     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., 51 Franklin Street, Fifth Floor,
+     Boston, MA 02110-1301, USA.
+*/
+
+/**
+ * @author Christian Grothoff
+ * @author Milan Bouchet-Valat
+ *
+ * @file nat/nat_api.c
+ * Service for handling UPnP and NAT-PMP port forwarding
+ * and external IP address retrieval
+ */
+#include "platform.h"
+#include "gnunet_nat_service.h"
+
+
+/**
+ * Handle for active NAT registrations.
+ */
+struct GNUNET_NAT_Handle
+{
+
+  /**
+   * Configuration we use.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+  
+  /**
+   * Message queue for communicating with the NAT service.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Our registration message.
+   */
+  struct GNUNET_MessageHeader *reg;
+  
+  /**
+   * Function to call when our addresses change.
+   */
+  GNUNET_NAT_AddressCallback address_callback;
+  
+  /**
+   * Function to call when another peer requests connection reversal.
+   */
+  GNUNET_NAT_ReversalCallback reversal_callback;
+  
+  /**
+   * Closure for the various callbacks.
+   */
+  void *callback_cls;
+
+};
+
+
+/**
+ * Attempt to enable port redirection and detect public IP address
+ * contacting UPnP or NAT-PMP routers on the local network. Use @a
+ * addr to specify to which of the local host's addresses should the
+ * external port be mapped. The port is taken from the corresponding
+ * sockaddr_in[6] field.  The NAT module should call the given @a
+ * address_callback for any 'plausible' external address.
+ *
+ * @param cfg configuration to use
+ * @param proto protocol this is about, IPPROTO_TCP or IPPROTO_UDP
+ * @param adv_port advertised port (port we are either bound to or that our OS
+ *                 locally performs redirection from to our bound port).
+ * @param num_addrs number of addresses in @a addrs
+ * @param addrs list of local addresses packets should be redirected to
+ * @param addrlens actual lengths of the addresses in @a addrs
+ * @param address_callback function to call everytime the public IP address changes
+ * @param reversal_callback function to call if someone wants connection reversal from us,
+ *        NULL if connection reversal is not supported
+ * @param callback_cls closure for callbacks
+ * @return NULL on error, otherwise handle that can be used to unregister
+ */
+struct GNUNET_NAT_Handle *
+GNUNET_NAT_register (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                     uint8_t proto,
+                     uint16_t adv_port,
+                     unsigned int num_addrs,
+                     const struct sockaddr **addrs,
+                     const socklen_t *addrlens,
+                     GNUNET_NAT_AddressCallback address_callback,
+                     GNUNET_NAT_ReversalCallback reversal_callback,
+                     void *callback_cls)
+{
+  struct GNUNET_NAT_Handle *nh = GNUNET_new (struct GNUNET_NAT_Handle);
+
+  nh->cfg = cfg;
+  nh->address_callback = address_callback;
+  nh->reversal_callback = reversal_callback;
+  nh->callback_cls = callback_cls;
+  GNUNET_break (0);
+  return nh;
+}
+
+
+/**
+ * Handle an incoming STUN message.  This function is useful as
+ * some GNUnet service may be listening on a UDP port and might
+ * thus receive STUN messages while trying to receive other data.
+ * In this case, this function can be used to act as a proper
+ * STUN server (if desired).
+ *
+ * The function does some basic sanity checks on packet size and
+ * content, try to extract a bit of information, and possibly replies
+ * if this is an actual STUN message.
+ * 
+ * At the moment this only processes BIND requests, and returns the
+ * externally visible address of the request. 
+ *
+ * @param nh handle to the NAT service
+ * @param sender_addr address from which we got @a data
+ * @param data the packet
+ * @param data_size number of bytes in @a data
+ * @return #GNUNET_OK on success
+ *         #GNUNET_NO if the packet is not a STUN packet
+ *         #GNUNET_SYSERR on internal error handling the packet
+ */
+int
+GNUNET_NAT_stun_handle_packet (struct GNUNET_NAT_Handle *nh,
+                               const struct sockaddr *sender_addr,
+                               const void *data,
+                               size_t data_size)
+{
+  GNUNET_break (0);
+  return GNUNET_SYSERR;
+}
+
+
+/**
+ * Test if the given address is (currently) a plausible IP address for
+ * this peer.  Mostly a convenience function so that clients do not
+ * have to explicitly track all IPs that the #GNUNET_NAT_AddressCallback
+ * has returned so far.
+ *
+ * @param nh the handle returned by register
+ * @param addr IP address to test (IPv4 or IPv6)
+ * @param addrlen number of bytes in @a addr
+ * @return #GNUNET_YES if the address is plausible,
+ *         #GNUNET_NO if the address is not plausible,
+ *         #GNUNET_SYSERR if the address is malformed
+ */
+int
+GNUNET_NAT_test_address (struct GNUNET_NAT_Handle *nh,
+                         const void *addr,
+                         socklen_t addrlen)
+{
+  GNUNET_break (0);
+  return GNUNET_SYSERR;
+}
+
+
+/**
+ * We learned about a peer (possibly behind NAT) so run the
+ * gnunet-nat-client to send dummy ICMP responses to cause
+ * that peer to connect to us (connection reversal).
+ *
+ * @param nh handle (used for configuration)
+ * @param local_sa our local address of the peer (IPv4-only)
+ * @param remote_sa the remote address of the peer (IPv4-only)
+ * @return #GNUNET_SYSERR on error, 
+ *         #GNUNET_NO if connection reversal is unavailable,
+ *         #GNUNET_OK otherwise (presumably in progress)
+ */
+int
+GNUNET_NAT_request_reversal (struct GNUNET_NAT_Handle *nh,
+                             const struct sockaddr_in *local_sa,
+                             const struct sockaddr_in *remote_sa)
+{
+  GNUNET_break (0);
+  return GNUNET_SYSERR;
+}
+
+
+/**
+ * Stop port redirection and public IP address detection for the given
+ * handle.  This frees the handle, after having sent the needed
+ * commands to close open ports.
+ *
+ * @param nh the handle to stop
+ */
+void
+GNUNET_NAT_unregister (struct GNUNET_NAT_Handle *nh)
+{
+  GNUNET_MQ_destroy (nh->mq);
+  GNUNET_free (nh->reg);
+  GNUNET_free (nh);
+}
+
+
+/**
+ * Handle to a NAT test.
+ */
+struct GNUNET_NAT_Test
+{
+
+  /**
+   * Configuration we use.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+  
+  /**
+   * Message queue for communicating with the NAT service.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Function called to report success or failure for
+   * NAT configuration test.
+   */
+  GNUNET_NAT_TestCallback cb;
+
+  /**
+   * Closure for @e cb.
+   */
+  void *cb_cls;
+
+};
+
+
+/**
+ * Start testing if NAT traversal works using the given configuration
+ * (IPv4-only).  The transport adapters should be down while using
+ * this function.
+ *
+ * @param cfg configuration for the NAT traversal
+ * @param proto protocol to test, i.e. IPPROTO_TCP or IPPROTO_UDP
+ * @param bind_ip IPv4 address to bind to
+ * @param bnd_port port to bind to, 0 to test connection reversal
+ * @param extern_ip IPv4 address to externally advertise
+ * @param extern_port externally advertised port to use
+ * @param report function to call with the result of the test
+ * @param report_cls closure for @a report
+ * @return handle to cancel NAT test
+ */
+struct GNUNET_NAT_Test *
+GNUNET_NAT_test_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                       uint8_t proto,
+                       struct in_addr bind_ip,
+                       uint16_t bnd_port,
+                       struct in_addr extern_ip,
+                       uint16_t extern_port,
+                       GNUNET_NAT_TestCallback report,
+                       void *report_cls)
+{
+  struct GNUNET_NAT_Test *tst = GNUNET_new (struct GNUNET_NAT_Test);
+
+  tst->cb = report;
+  tst->cb_cls = report_cls;
+  GNUNET_break (0);
+  return tst;
+}
+
+
+/**
+ * Stop an active NAT test.
+ *
+ * @param tst test to stop.
+ */
+void
+GNUNET_NAT_test_stop (struct GNUNET_NAT_Test *tst)
+{
+  GNUNET_break (0);
+  GNUNET_MQ_destroy (tst->mq);
+  GNUNET_free (tst);
+}
+
+
+/**
+ * Handle to auto-configuration in progress.
+ */
+struct GNUNET_NAT_AutoHandle
+{
+
+  /**
+   * Configuration we use.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+  
+  /**
+   * Message queue for communicating with the NAT service.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Function called with the result from the autoconfiguration.
+   */
+  GNUNET_NAT_AutoResultCallback arc;
+
+  /**
+   * Closure for @e arc.
+   */
+  void *arc_cls;
+
+};
+
+
+/**
+ * Converts `enum GNUNET_NAT_StatusCode` to string
+ *
+ * @param err error code to resolve to a string
+ * @return point to a static string containing the error code
+ */
+const char *
+GNUNET_NAT_status2string (enum GNUNET_NAT_StatusCode err)
+{
+  GNUNET_break (0);
+  return NULL;
+}
+
+
+/**
+ * Start auto-configuration routine.  The transport adapters should
+ * be stopped while this function is called.
+ *
+ * @param cfg initial configuration
+ * @param cb function to call with autoconfiguration result
+ * @param cb_cls closure for @a cb
+ * @return handle to cancel operation
+ */
+struct GNUNET_NAT_AutoHandle *
+GNUNET_NAT_autoconfig_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                             GNUNET_NAT_AutoResultCallback cb,
+                             void *cb_cls)
+{
+  struct GNUNET_NAT_AutoHandle *ah = GNUNET_new (struct GNUNET_NAT_AutoHandle);
+
+  ah->cfg = cfg;
+  ah->arc = cb;
+  ah->arc_cls = cb_cls;
+  GNUNET_break (0);
+  return ah;
+}
+
+
+/**
+ * Abort autoconfiguration.
+ *
+ * @param ah handle for operation to abort
+ */
+void
+GNUNET_NAT_autoconfig_cancel (struct GNUNET_NAT_AutoHandle *ah)
+{
+  GNUNET_break (0);
+  GNUNET_MQ_destroy (ah->mq);
+  GNUNET_free (ah);
+}
+
+/* end of nat_api.c */