path: root/src/ats/ats_api_scheduling.c

/*
     This file is part of GNUnet.
     (C) 2010-2015 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 ats/ats_api_scheduling.c
 * @brief automatic transport selection and outbound bandwidth determination
 * @author Christian Grothoff
 * @author Matthias Wachs
 *
 * TODO:
 * - we could avoid a linear scan over the
 *   active addresses in some cases, so if
 *   there is need, we can still optimize here
 * - we might want to split off the logic to
 *   determine LAN vs. WAN, as it has nothing
 *   to do with accessing the ATS service.
 */
#include "platform.h"
#include "gnunet_ats_service.h"
#include "ats.h"

/**
 * How frequently do we scan the interfaces for changes to the addresses?
 */
#define INTERFACE_PROCESSING_INTERVAL GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 2)


/**
 * Session ID we use if there is no session / slot.
 */
#define NOT_FOUND 0


/**
 * Information we track per address, incoming or outgoing.  It also
 * doesn't matter if we have a session, any address that ATS is
 * allowed to suggest right now should be tracked.
 */
struct GNUNET_ATS_AddressRecord
{

  /**
   * Scheduling handle this address record belongs to.
   */
  struct GNUNET_ATS_SchedulingHandle *sh;

  /**
   * Address data.
   */
  struct GNUNET_HELLO_Address *address;

  /**
   * Session handle.  NULL if we have an address but no
   * active session for this address.
   */
  struct Session *session;

  /**
   * Array with performance data about the address.
   */
  struct GNUNET_ATS_Information *ats;

  /**
   * Number of entries in @e ats.
   */
  uint32_t ats_count;

  /**
   * Which slot (index) in the session array does
   * this record correspond to?  FIXME:
   * FIXME: a linear search on this is really crappy!
   * Maybe switch to a 64-bit global counter and be
   * done with it?  Or does that then cause too much
   * trouble on the ATS-service side?
   */
  uint32_t slot;

  /**
   * Is this address currently in use?  In use means
   * that the transport service will use this address
   * for sending.
   */
  int in_use;

  /**
   * We're about to destroy this address record, just ATS does
   * not know this yet.  Once ATS confirms its destruction,
   * we can clean up.
   */
  int in_destroy;
};


/**
 * We keep a list of our local networks so we can answer
 * LAN vs. WAN questions.  Note: WLAN is not detected yet.
 * (maybe we can do that heuristically based on interface
 * name in the future?).
 *
 * FIXME: should this be part of the ATS scheduling API?
 * Seems to be more generic and independent of ATS.
 */
struct ATS_Network
{
  /**
   * Kept in a DLL.
   */
  struct ATS_Network *next;

  /**
   * Kept in a DLL.
   */
  struct ATS_Network *prev;

  /**
   * Network address.
   */
  struct sockaddr *network;

  /**
   * Netmask to determine what is in the LAN.
   */
  struct sockaddr *netmask;

  /**
   * How long are @e network and @e netmask?
   */
  socklen_t length;
};


/**
 * Handle for ATS address suggestion requests.
 */
struct GNUNET_ATS_SuggestHandle
{
  /**
   * ID of the peer for which address suggestion was requested.
   */
  struct GNUNET_PeerIdentity id;
};


/**
 * Handle to the ATS subsystem for bandwidth/transport scheduling information.
 */
struct GNUNET_ATS_SchedulingHandle
{

  /**
   * Our configuration.
   */
  const struct GNUNET_CONFIGURATION_Handle *cfg;

  /**
   * Callback to invoke on suggestions.
   */
  GNUNET_ATS_AddressSuggestionCallback suggest_cb;

  /**
   * Closure for @e suggest_cb.
   */
  void *suggest_cb_cls;

  /**
   * Map with the identities of all the peers for which we would
   * like to have address suggestions.  The key is the PID, the
   * value is currently the `struct GNUNET_ATS_SuggestHandle`
   */
  struct GNUNET_CONTAINER_MultiPeerMap *sug_requests;

  /**
   * Connection to ATS service.
   */
  struct GNUNET_CLIENT_Connection *client;

  /**
   * Message queue for sending requests to the ATS service.
   */
  struct GNUNET_MQ_Handle *mq;

  /**
   * Head of LAN networks list.
   */
  struct ATS_Network *net_head;

  /**
   * Tail of LAN networks list.
   */
  struct ATS_Network *net_tail;

  /**
   * Array of session objects (we need to translate them to numbers and back
   * for the protocol; the offset in the array is the session number on the
   * network).  Index 0 is always NULL and reserved to represent the NULL pointer.
   * Unused entries are also NULL.
   */
  struct GNUNET_ATS_AddressRecord **session_array;

  /**
   * Task to trigger reconnect.
   */
  struct GNUNET_SCHEDULER_Task *task;

  /**
   * Task for periodically refreshing our LAN network list.
   */
  struct GNUNET_SCHEDULER_Task *interface_task;

  /**
   * Size of the @e session_array.
   */
  unsigned int session_array_size;

};


/**
 * Re-establish the connection to the ATS service.
 *
 * @param sh handle to use to re-connect.
 */
static void
reconnect (struct GNUNET_ATS_SchedulingHandle *sh);


/**
 * Re-establish the connection to the ATS service.
 *
 * @param cls handle to use to re-connect.
 * @param tc scheduler context
 */
static void
reconnect_task (void *cls,
                const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;

  sh->task = NULL;
  reconnect (sh);
}


/**
 * Disconnect from ATS and then reconnect.
 *
 * @param sh our handle
 */
static void
force_reconnect (struct GNUNET_ATS_SchedulingHandle *sh)
{
  if (NULL != sh->mq)
  {
    GNUNET_MQ_destroy (sh->mq);
    sh->mq = NULL;
  }
  if (NULL != sh->client)
  {
    GNUNET_CLIENT_disconnect (sh->client);
    sh->client = NULL;
  }
  sh->task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
                                           &reconnect_task,
                                           sh);
}


/**
 * Find the session object corresponding to the given session ID.
 *
 * @param sh our handle
 * @param session_id current session ID
 * @param peer peer the session belongs to
 * @return the session object (or NULL)
 */
static struct GNUNET_ATS_AddressRecord *
find_session (struct GNUNET_ATS_SchedulingHandle *sh,
              uint32_t session_id,
              const struct GNUNET_PeerIdentity *peer)
{
  struct GNUNET_ATS_AddressRecord *ar;

  if (session_id >= sh->session_array_size)
  {
    GNUNET_break (0);
    return NULL;
  }
  if (0 == session_id)
    return NULL;
  ar = sh->session_array[session_id];
  if (NULL == ar)
  {
    GNUNET_break (0);
    return NULL;
  }
  if (NULL == ar->address)
  {
    /* address was destroyed in the meantime, this can happen
       as we communicate asynchronously with the ATS service. */
    return NULL;
  }
  if (0 != memcmp (peer,
                   &ar->address->peer,
                   sizeof (struct GNUNET_PeerIdentity)))
  {
    GNUNET_break (0);
    force_reconnect (sh);
    return NULL;
  }
  return ar;
}


/**
 * Get an available session ID.
 *
 * @param sh our handle
 * @return an unused slot, but never NOT_FOUND (0)
 */
static uint32_t
find_empty_session_slot (struct GNUNET_ATS_SchedulingHandle *sh)
{
  static uint32_t off;
  uint32_t i;

  i = 0;
  while ( ( (NOT_FOUND == off) ||
            (NULL != sh->session_array[off % sh->session_array_size]) ) &&
          (i < sh->session_array_size) )
  {
    off++;
    i++;
  }
  if ( (NOT_FOUND != off % sh->session_array_size) &&
       (NULL == sh->session_array[off % sh->session_array_size]) )
    return off;
  i = sh->session_array_size;
  GNUNET_array_grow (sh->session_array,
                     sh->session_array_size,
                     sh->session_array_size * 2);
  return i;
}


/**
 * Get the ID for the given session object.
 *
 * @param sh our handle
 * @param session session object
 * @param address the address we are looking for
 * @return the session id or NOT_FOUND for error
 */
static uint32_t
find_session_id (struct GNUNET_ATS_SchedulingHandle *sh,
                 struct Session *session,
                 const struct GNUNET_HELLO_Address *address)
{
  uint32_t i;

  if (NULL == address)
  {
    GNUNET_break (0);
    return NOT_FOUND;
  }
  for (i = 1; i < sh->session_array_size; i++)
    if ( (NULL != sh->session_array[i]) &&
         ( (session == sh->session_array[i]->session) ||
           (NULL == sh->session_array[i]->session) ) &&
         (0 == GNUNET_HELLO_address_cmp (address,
                                         sh->session_array[i]->address)) )
      return i;
  return NOT_FOUND;
}


/**
 * Release the session slot from the session table (ATS service is
 * also done using it).
 *
 * @param sh our handle
 * @param session_id identifies session that is no longer valid
 */
static void
release_session (struct GNUNET_ATS_SchedulingHandle *sh,
                 uint32_t session_id)
{
  struct GNUNET_ATS_AddressRecord *ar;

  if (NOT_FOUND == session_id)
    return;
  if (session_id >= sh->session_array_size)
  {
    GNUNET_break (0);
    force_reconnect (sh);
    return;
  }
  /* this slot should have been removed from remove_session before */
  ar = sh->session_array[session_id];
  if (NULL != ar->session)
  {
    GNUNET_break (0);
    force_reconnect (sh);
    return;
  }
  GNUNET_HELLO_address_free (ar->address);
  GNUNET_free (ar);
  sh->session_array[session_id] = NULL;
}


/**
 * Type of a function to call when we receive a session release
 * message from the service.
 *
 * @param cls the `struct GNUNET_ATS_SchedulingHandle`
 * @param msg message received, NULL on timeout or fatal error
 */
static void
process_ats_session_release_message (void *cls,
                                     const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;
  const struct SessionReleaseMessage *srm;

  srm = (const struct SessionReleaseMessage *) msg;
  /* Note: peer field in srm not necessary right now,
     but might be good to have in the future */
  release_session (sh,
                   ntohl (srm->session_id));
}


/**
 * Type of a function to call when we receive a address suggestion
 * message from the service.
 *
 * @param cls the `struct GNUNET_ATS_SchedulingHandle`
 * @param msg message received, NULL on timeout or fatal error
 */
static void
process_ats_address_suggestion_message (void *cls,
                                        const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;
  const struct AddressSuggestionMessage *m;
  struct GNUNET_ATS_AddressRecord *ar;
  uint32_t session_id;

  m = (const struct AddressSuggestionMessage *) msg;
  session_id = ntohl (m->session_id);
  if (0 == session_id)
  {
    GNUNET_break (0);
    force_reconnect (sh);
    return;
  }
  ar = find_session (sh, session_id, &m->peer);
  if (NULL == ar)
  {
    GNUNET_break (0);
    force_reconnect (sh);
    return;
  }
  if (NULL == sh->suggest_cb)
    return;
  if (GNUNET_YES == ar->in_destroy)
  {
    /* ignore suggestion, as this address is dying */
    return;
  }
  if ( (NULL == ar->session) &&
       (GNUNET_HELLO_address_check_option (ar->address,
                                           GNUNET_HELLO_ADDRESS_INFO_INBOUND)) )
  {
    GNUNET_assert (0); // FIXME: turn back into 'break' later!
    return;
  }
  sh->suggest_cb (sh->suggest_cb_cls,
                  &m->peer,
                  ar->address,
                  ar->session,
                  m->bandwidth_out,
                  m->bandwidth_in);
}


/**
 * We encountered an error handling the MQ to the
 * ATS service.  Reconnect.
 *
 * @param cls the `struct GNUNET_ATS_SchedulingHandle`
 * @param error details about the error
 */
static void
error_handler (void *cls,
               enum GNUNET_MQ_Error error)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;

  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
              "ATS connection died (code %d), reconnecting\n",
              (int) error);
  force_reconnect (sh);
}


/**
 * Generate and transmit the `struct AddressAddMessage` for the given
 * address record.
 *
 * @param sh the scheduling handle to use for transmission
 * @param ar the address to inform the ATS service about
 */
static void
send_add_address_message (struct GNUNET_ATS_SchedulingHandle *sh,
                          const struct GNUNET_ATS_AddressRecord *ar)
{
  struct GNUNET_MQ_Envelope *ev;
  struct AddressAddMessage *m;
  struct GNUNET_ATS_Information *am;
  char *pm;
  size_t namelen;
  size_t msize;

  if (NULL == sh->mq)
    return; /* disconnected, skip for now */
  namelen = (NULL == ar->address->transport_name)
    ? 0
    : strlen (ar->address->transport_name) + 1;
  msize = ar->address->address_length +
    ar->ats_count * sizeof (struct GNUNET_ATS_Information) + namelen;

  ev = GNUNET_MQ_msg_extra (m, msize, GNUNET_MESSAGE_TYPE_ATS_ADDRESS_ADD);
  m->ats_count = htonl (ar->ats_count);
  m->peer = ar->address->peer;
  m->address_length = htons (ar->address->address_length);
  m->address_local_info = htonl ((uint32_t) ar->address->local_info);
  m->plugin_name_length = htons (namelen);
  m->session_id = htonl (ar->slot);

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Adding address for peer `%s', plugin `%s', session %p id %u\n",
              GNUNET_i2s (&ar->address->peer),
              ar->address->transport_name,
              ar->session,
              ar->slot);
  am = (struct GNUNET_ATS_Information *) &m[1];
  memcpy (am,
          ar->ats,
          ar->ats_count * sizeof (struct GNUNET_ATS_Information));
  pm = (char *) &am[ar->ats_count];
  memcpy (pm,
          ar->address->address,
          ar->address->address_length);
  if (NULL != ar->address->transport_name)
    memcpy (&pm[ar->address->address_length],
            ar->address->transport_name,
            namelen);
  GNUNET_MQ_send (sh->mq, ev);
}


/**
 * Transmit request for an address suggestion.
 *
 * @param cls the `struct GNUNET_ATS_SchedulingHandle`
 * @param peer peer to ask for an address suggestion for
 * @param value the `struct GNUNET_ATS_SuggestHandle`
 * @return #GNUNET_OK (continue to iterate), #GNUNET_SYSERR on
 *         failure (message queue no longer exists)
 */
static int
transmit_suggestion (void *cls,
                     const struct GNUNET_PeerIdentity *peer,
                     void *value)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;
  struct GNUNET_MQ_Envelope *ev;
  struct RequestAddressMessage *m;

  if (NULL == sh->mq)
    return GNUNET_SYSERR;
  ev = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_ATS_REQUEST_ADDRESS);
  m->reserved = htonl (0);
  m->peer = *peer;
  GNUNET_MQ_send (sh->mq, ev);
  return GNUNET_OK;
}


/**
 * Generate and transmit the `struct AddressUseMessage` for the given
 * address record.
 *
 * @param ar the address to inform the ATS service about
 * @param in_use say if it is in use or not
 */
static void
send_in_use_message (struct GNUNET_ATS_AddressRecord *ar,
                     int in_use)
{
  struct GNUNET_ATS_SchedulingHandle *sh = ar->sh;
  struct GNUNET_MQ_Envelope *ev;
  struct AddressUseMessage *m;

  ev = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_ATS_ADDRESS_IN_USE);
  m->peer = ar->address->peer;
  m->in_use = htonl ((uint32_t) in_use);
  m->session_id = htonl (ar->slot);
  GNUNET_MQ_send (sh->mq, ev);
}


/**
 * Re-establish the connection to the ATS service.
 *
 * @param sh handle to use to re-connect.
 */
static void
reconnect (struct GNUNET_ATS_SchedulingHandle *sh)
{
  static const struct GNUNET_MQ_MessageHandler handlers[] =
    { { &process_ats_session_release_message,
        GNUNET_MESSAGE_TYPE_ATS_SESSION_RELEASE,
        sizeof (struct SessionReleaseMessage) },
      { &process_ats_address_suggestion_message,
        GNUNET_MESSAGE_TYPE_ATS_ADDRESS_SUGGESTION,
        sizeof (struct AddressSuggestionMessage) },
      { NULL, 0, 0 } };
  struct GNUNET_MQ_Envelope *ev;
  struct ClientStartMessage *init;
  unsigned int i;
  struct GNUNET_ATS_AddressRecord *ar;

  GNUNET_assert (NULL == sh->client);
  sh->client = GNUNET_CLIENT_connect ("ats", sh->cfg);
  if (NULL == sh->client)
  {
    force_reconnect (sh);
    return;
  }
  sh->mq = GNUNET_MQ_queue_for_connection_client (sh->client,
                                                  handlers,
                                                  &error_handler,
                                                  sh);
  ev = GNUNET_MQ_msg (init,
                      GNUNET_MESSAGE_TYPE_ATS_START);
  init->start_flag = htonl (START_FLAG_SCHEDULING);
  GNUNET_MQ_send (sh->mq, ev);
  if (NULL == sh->mq)
    return;
  for (i=0;i<sh->session_array_size;i++)
  {
    ar = sh->session_array[i];
    if (NULL == ar)
      continue;
    send_add_address_message (sh, ar);
    if (ar->in_use)
      send_in_use_message (ar, GNUNET_YES);
    if (NULL == sh->mq)
      return;
  }
  GNUNET_CONTAINER_multipeermap_iterate (sh->sug_requests,
                                         &transmit_suggestion,
                                         sh);
}


/**
 * Delete all entries from the current network list.
 *
 * @param sh scheduling handle to clean up
 */
static void
delete_networks (struct GNUNET_ATS_SchedulingHandle *sh)
{
  struct ATS_Network *cur;

  while (NULL != (cur = sh->net_head))
  {
    GNUNET_CONTAINER_DLL_remove (sh->net_head,
                                 sh->net_tail,
                                 cur);
    GNUNET_free (cur);
  }
}


/**
 * Function invoked for each interface found.  Adds the interface's
 * network addresses to the respective DLL, so we can distinguish
 * between LAN and WAN.
 *
 * @param cls closure
 * @param name name of the interface (can be NULL for unknown)
 * @param isDefault is this presumably the default interface
 * @param addr address of this interface (can be NULL for unknown or unassigned)
 * @param broadcast_addr the broadcast address (can be NULL for unknown or unassigned)
 * @param netmask the network mask (can be NULL for unknown or unassigned)
 * @param addrlen length of the address
 * @return #GNUNET_OK to continue iteration
 */
static int
interface_proc (void *cls,
                const char *name,
                int isDefault,
                const struct sockaddr *addr,
                const struct sockaddr *broadcast_addr,
                const struct sockaddr *netmask,
                socklen_t addrlen)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;
  /* Calculate network */
  struct ATS_Network *net = NULL;

  /* Skipping IPv4 loopback addresses since we have special check  */
  if  (addr->sa_family == AF_INET)
  {
    const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;

    if ((a4->sin_addr.s_addr & htonl(0xff000000)) == htonl (0x7f000000))
       return GNUNET_OK;
  }
  /* Skipping IPv6 loopback addresses since we have special check  */
  if  (addr->sa_family == AF_INET6)
  {
    const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
    if (IN6_IS_ADDR_LOOPBACK (&a6->sin6_addr))
      return GNUNET_OK;
  }

  if (addr->sa_family == AF_INET)
  {
    const struct sockaddr_in *addr4 = (const struct sockaddr_in *) addr;
    const struct sockaddr_in *netmask4 = (const struct sockaddr_in *) netmask;
    struct sockaddr_in *tmp;
    struct sockaddr_in network4;

    net = GNUNET_malloc (sizeof (struct ATS_Network) + 2 * sizeof (struct sockaddr_in));
    tmp = (struct sockaddr_in *) &net[1];
    net->network = (struct sockaddr *) &tmp[0];
    net->netmask = (struct sockaddr *) &tmp[1];
    net->length = addrlen;

    memset (&network4, 0, sizeof (network4));
    network4.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
    network4.sin_len = sizeof (network4);
#endif
    network4.sin_addr.s_addr = (addr4->sin_addr.s_addr & netmask4->sin_addr.s_addr);

    memcpy (net->netmask, netmask4, sizeof (struct sockaddr_in));
    memcpy (net->network, &network4, sizeof (struct sockaddr_in));
  }

  if (addr->sa_family == AF_INET6)
  {
    const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr;
    const struct sockaddr_in6 *netmask6 = (const struct sockaddr_in6 *) netmask;
    struct sockaddr_in6 * tmp;
    struct sockaddr_in6 network6;

    net = GNUNET_malloc (sizeof (struct ATS_Network) + 2 * sizeof (struct sockaddr_in6));
    tmp = (struct sockaddr_in6 *) &net[1];
    net->network = (struct sockaddr *) &tmp[0];
    net->netmask = (struct sockaddr *) &tmp[1];
    net->length = addrlen;

    memset (&network6, 0, sizeof (network6));
    network6.sin6_family = AF_INET6;
#if HAVE_SOCKADDR_IN_SIN_LEN
    network6.sin6_len = sizeof (network6);
#endif
    unsigned int c = 0;
    uint32_t *addr_elem = (uint32_t *) &addr6->sin6_addr;
    uint32_t *mask_elem = (uint32_t *) &netmask6->sin6_addr;
    uint32_t *net_elem = (uint32_t *) &network6.sin6_addr;
    for (c = 0; c < 4; c++)
      net_elem[c] = addr_elem[c] & mask_elem[c];

    memcpy (net->netmask, netmask6, sizeof (struct sockaddr_in6));
    memcpy (net->network, &network6, sizeof (struct sockaddr_in6));
  }
  if (NULL == net)
    return GNUNET_OK; /* odd / unsupported address family */

  /* Store in list */
#if VERBOSE_ATS
  char * netmask = GNUNET_strdup (GNUNET_a2s((struct sockaddr *) net->netmask, addrlen));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Adding network `%s', netmask `%s'\n",
              GNUNET_a2s ((struct sockaddr *) net->network,
                          addrlen),
              netmask);
  GNUNET_free (netmask);
#endif
  GNUNET_CONTAINER_DLL_insert (sh->net_head,
                               sh->net_tail,
                               net);

  return GNUNET_OK;
}


/**
 * Periodically get list of network addresses from our interfaces.
 *
 * @param cls closure
 * @param tc Task context
 */
static void
get_addresses (void *cls,
               const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;

  sh->interface_task = NULL;
  delete_networks (sh);
  GNUNET_OS_network_interfaces_list (&interface_proc,
                                     sh);
  sh->interface_task = GNUNET_SCHEDULER_add_delayed (INTERFACE_PROCESSING_INTERVAL,
                                                     &get_addresses,
                                                     sh);
}


/**
 * Convert a `enum GNUNET_ATS_Network_Type` to a string
 *
 * @param net the network type
 * @return a string or NULL if invalid
 */
const char *
GNUNET_ATS_print_network_type (enum GNUNET_ATS_Network_Type net)
{
  switch (net)
    {
    case GNUNET_ATS_NET_UNSPECIFIED:
      return "UNSPECIFIED";
    case GNUNET_ATS_NET_LOOPBACK:
      return "LOOPBACK";
    case GNUNET_ATS_NET_LAN:
      return "LAN";
    case GNUNET_ATS_NET_WAN:
      return "WAN";
    case GNUNET_ATS_NET_WLAN:
      return "WLAN";
    case GNUNET_ATS_NET_BT:
      return "BLUETOOTH";
    default:
      return NULL;
    }
}


/**
 * Convert a ATS property to a string
 *
 * @param type the property type
 * @return a string or NULL if invalid
 */
const char *
GNUNET_ATS_print_property_type (enum GNUNET_ATS_Property type)
{
  switch (type)
  {
  case GNUNET_ATS_ARRAY_TERMINATOR:
    return "TERMINATOR";
  case GNUNET_ATS_UTILIZATION_OUT:
    return "UTILIZATION_UP";
  case GNUNET_ATS_UTILIZATION_IN:
    return "UTILIZATION_DOWN";
  case GNUNET_ATS_UTILIZATION_PAYLOAD_OUT:
    return "UTILIZATION_PAYLOAD_UP";
  case GNUNET_ATS_UTILIZATION_PAYLOAD_IN:
    return "UTILIZATION_PAYLOAD_DOWN";
  case GNUNET_ATS_NETWORK_TYPE:
    return "NETWORK_TYPE";
  case GNUNET_ATS_QUALITY_NET_DELAY:
    return "DELAY";
  case GNUNET_ATS_QUALITY_NET_DISTANCE:
    return "DISTANCE";
  case GNUNET_ATS_COST_WAN:
    return "COST_WAN";
  case GNUNET_ATS_COST_LAN:
    return "COST_LAN";
  case GNUNET_ATS_COST_WLAN:
    return "COST_WLAN";
  default:
    return NULL;
  }
}


/**
 * Returns where the address is located: LAN or WAN or ...
 *
 * @param sh the scheduling handle
 * @param addr address
 * @param addrlen address length
 * @return type of the network the address belongs to
 */
enum GNUNET_ATS_Network_Type
GNUNET_ATS_address_get_type (struct GNUNET_ATS_SchedulingHandle *sh,
                             const struct sockaddr *addr,
                             socklen_t addrlen)
{
  struct ATS_Network *cur = sh->net_head;
  enum GNUNET_ATS_NetworkType type = GNUNET_ATS_NET_UNSPECIFIED;

  switch (addr->sa_family)
    {
    case AF_UNIX:
      type = GNUNET_ATS_NET_LOOPBACK;
      break;
    case AF_INET:
      {
        const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;

        if ((a4->sin_addr.s_addr & htonl(0xff000000)) == htonl (0x7f000000))
          type = GNUNET_ATS_NET_LOOPBACK;
        break;
      }
    case AF_INET6:
      {
        const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;

        if (IN6_IS_ADDR_LOOPBACK (&a6->sin6_addr))
          type = GNUNET_ATS_NET_LOOPBACK;
        break;
      }
    default:
      GNUNET_break (0);
      break;
   }

  /* Check local networks */
  while ((NULL != cur) && (GNUNET_ATS_NET_UNSPECIFIED == type))
  {
    if (addrlen != cur->length)
    {
      cur = cur->next;
      continue;
    }
    if (addr->sa_family == AF_INET)
    {
      const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;
      const struct sockaddr_in *net4 = (const struct sockaddr_in *) cur->network;
      const struct sockaddr_in *mask4 = (const struct sockaddr_in *) cur->netmask;

      if (((a4->sin_addr.s_addr & mask4->sin_addr.s_addr)) == net4->sin_addr.s_addr)
        type = GNUNET_ATS_NET_LAN;
    }
    if (addr->sa_family == AF_INET6)
    {
      const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
      const struct sockaddr_in6 *net6 = (const struct sockaddr_in6 *) cur->network;
      const struct sockaddr_in6 *mask6 = (const struct sockaddr_in6 *) cur->netmask;

      int res = GNUNET_YES;
      int c = 0;
      uint32_t *addr_elem = (uint32_t *) &a6->sin6_addr;
      uint32_t *mask_elem = (uint32_t *) &mask6->sin6_addr;
      uint32_t *net_elem = (uint32_t *) &net6->sin6_addr;
      for (c = 0; c < 4; c++)
        if ((addr_elem[c] & mask_elem[c]) != net_elem[c])
          res = GNUNET_NO;

      if (res == GNUNET_YES)
        type = GNUNET_ATS_NET_LAN;
    }
    cur = cur->next;
  }

  /* no local network found for this address, default: WAN */
  if (type == GNUNET_ATS_NET_UNSPECIFIED)
    type = GNUNET_ATS_NET_WAN;
  GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
                   "ats-scheduling-api",
                   "`%s' is in network `%s'\n",
                   GNUNET_a2s (addr,
                               addrlen),
                   GNUNET_ATS_print_network_type (type));
  return type;
}


/**
 * Initialize the ATS subsystem.
 *
 * @param cfg configuration to use
 * @param suggest_cb notification to call whenever the suggestation changed
 * @param suggest_cb_cls closure for @a suggest_cb
 * @return ats context
 */
struct GNUNET_ATS_SchedulingHandle *
GNUNET_ATS_scheduling_init (const struct GNUNET_CONFIGURATION_Handle *cfg,
                            GNUNET_ATS_AddressSuggestionCallback suggest_cb,
                            void *suggest_cb_cls)
{
  struct GNUNET_ATS_SchedulingHandle *sh;

  sh = GNUNET_new (struct GNUNET_ATS_SchedulingHandle);
  sh->cfg = cfg;
  sh->suggest_cb = suggest_cb;
  sh->suggest_cb_cls = suggest_cb_cls;
  GNUNET_array_grow (sh->session_array,
                     sh->session_array_size,
                     4);
  sh->sug_requests = GNUNET_CONTAINER_multipeermap_create (32,
                                                           GNUNET_YES);
  GNUNET_OS_network_interfaces_list (&interface_proc,
                                     sh);
  sh->interface_task = GNUNET_SCHEDULER_add_delayed (INTERFACE_PROCESSING_INTERVAL,
                                                     &get_addresses,
                                                     sh);
  reconnect (sh);
  return sh;
}


/**
 * Function called to free all `struct GNUNET_ATS_SuggestHandles`
 * in the map.
 *
 * @param cls NULL
 * @param key the key
 * @param value the value to free
 * @return #GNUNET_OK (continue to iterate)
 */
static int
free_sug_handle (void *cls,
                 const struct GNUNET_PeerIdentity *key,
                 void *value)
{
  struct GNUNET_ATS_SuggestHandle *cur = value;

  GNUNET_free (cur);
  return GNUNET_OK;
}


/**
 * Client is done with ATS scheduling, release resources.
 *
 * @param sh handle to release
 */
void
GNUNET_ATS_scheduling_done (struct GNUNET_ATS_SchedulingHandle *sh)
{
  if (NULL != sh->mq)
  {
    GNUNET_MQ_destroy (sh->mq);
    sh->mq = NULL;
  }
  if (NULL != sh->client)
  {
    GNUNET_CLIENT_disconnect (sh->client);
    sh->client = NULL;
  }
  if (NULL != sh->task)
  {
    GNUNET_SCHEDULER_cancel (sh->task);
    sh->task = NULL;
  }
  GNUNET_CONTAINER_multipeermap_iterate (sh->sug_requests,
                                         &free_sug_handle,
                                         NULL);
  GNUNET_CONTAINER_multipeermap_destroy (sh->sug_requests);
  if (NULL != sh->interface_task)
  {
    GNUNET_SCHEDULER_cancel (sh->interface_task);
    sh->interface_task = NULL;
  }
  delete_networks (sh);
  GNUNET_array_grow (sh->session_array,
                     sh->session_array_size,
                     0);
  GNUNET_free (sh);
}


/**
 * We would like to reset the address suggestion block time for this
 * peer.
 *
 * @param sh handle
 * @param peer identity of the peer we want to reset
 */
void
GNUNET_ATS_reset_backoff (struct GNUNET_ATS_SchedulingHandle *sh,
                          const struct GNUNET_PeerIdentity *peer)
{
  struct GNUNET_MQ_Envelope *ev;
  struct ResetBackoffMessage *m;

  ev = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_ATS_RESET_BACKOFF);
  m->reserved = htonl (0);
  m->peer = *peer;
  GNUNET_MQ_send (sh->mq, ev);
}


/**
 * We would like to receive address suggestions for a peer. ATS will
 * respond with a call to the continuation immediately containing an address or
 * no address if none is available. ATS can suggest more addresses until we call
 * #GNUNET_ATS_suggest_address_cancel().
 *
 * @param sh handle
 * @param peer identity of the peer we need an address for
 * @return suggest handle, NULL if a request is already pending
 */
struct GNUNET_ATS_SuggestHandle *
GNUNET_ATS_suggest_address (struct GNUNET_ATS_SchedulingHandle *sh,
                            const struct GNUNET_PeerIdentity *peer)
{
  struct GNUNET_ATS_SuggestHandle *s;

  s = GNUNET_new (struct GNUNET_ATS_SuggestHandle);
  s->id = *peer;
  if (GNUNET_OK !=
      GNUNET_CONTAINER_multipeermap_put (sh->sug_requests,
                                         &s->id,
                                         s,
                                         GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY))
  {
    GNUNET_break (0);
    return NULL;
  }
  if (NULL == sh->mq)
    return s;
  (void) transmit_suggestion (sh,
                              &s->id,
                              s);
  return s;
}


/**
 * We would like to stop receiving address updates for this peer
 *
 * @param sh handle
 * @param peer identity of the peer
 */
void
GNUNET_ATS_suggest_address_cancel (struct GNUNET_ATS_SchedulingHandle *sh,
                                   const struct GNUNET_PeerIdentity *peer)
{
  struct GNUNET_MQ_Envelope *ev;
  struct RequestAddressMessage *m;
  struct GNUNET_ATS_SuggestHandle *s;

  s = GNUNET_CONTAINER_multipeermap_get (sh->sug_requests,
                                         peer);
  if (NULL == s)
  {
    GNUNET_break (0);
    return;
  }
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_CONTAINER_multipeermap_remove (sh->sug_requests,
                                                       &s->id,
                                                       s));
  GNUNET_free (s);
  if (NULL == sh->mq)
    return;
  ev = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_ATS_REQUEST_ADDRESS_CANCEL);
  m->reserved = htonl (0);
  m->peer = *peer;
  GNUNET_MQ_send (sh->mq, ev);
}


/**
 * Test if a address and a session is known to ATS
 *
 * @param sh the scheduling handle
 * @param address the address
 * @param session the session
 * @return #GNUNET_YES or #GNUNET_NO
 */
int
GNUNET_ATS_session_known (struct GNUNET_ATS_SchedulingHandle *sh,
                          const struct GNUNET_HELLO_Address *address,
                          struct Session *session)
{
  if (NULL == session)
    return GNUNET_NO;
  if (NOT_FOUND != find_session_id (sh,
                                    session,
                                    address))
    return GNUNET_YES;  /* Exists */
  return GNUNET_NO;
}


/**
 * We have a new address ATS should know. Addresses have to be added
 * with this function before they can be: updated, set in use and
 * destroyed.
 *
 * @param sh handle
 * @param address the address
 * @param session session handle, can be NULL
 * @param ats performance data for the address
 * @param ats_count number of performance records in @a ats
 * @return handle to the address representation inside ATS, NULL
 *         on error (i.e. ATS knows this exact address already)
 */
struct GNUNET_ATS_AddressRecord *
GNUNET_ATS_address_add (struct GNUNET_ATS_SchedulingHandle *sh,
                        const struct GNUNET_HELLO_Address *address,
                        struct Session *session,
                        const struct GNUNET_ATS_Information *ats,
                        uint32_t ats_count)
{
  struct GNUNET_ATS_AddressRecord *ar;
  size_t namelen;
  size_t msize;
  uint32_t s;

  if (NULL == address)
  {
    /* we need a valid address */
    GNUNET_break (0);
    return NULL;
  }
  namelen = (NULL == address->transport_name)
    ? 0
    : strlen (address->transport_name) + 1;
  msize = address->address_length +
    ats_count * sizeof (struct GNUNET_ATS_Information) + namelen;
  if ((msize + sizeof (struct AddressUpdateMessage) >= GNUNET_SERVER_MAX_MESSAGE_SIZE) ||
      (address->address_length >= GNUNET_SERVER_MAX_MESSAGE_SIZE) ||
      (namelen >= GNUNET_SERVER_MAX_MESSAGE_SIZE) ||
      (ats_count >=
       GNUNET_SERVER_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_ATS_Information)))
  {
    /* address too large for us, this should not happen */
    GNUNET_break (0);
    return NULL;
  }

  if (NOT_FOUND != find_session_id (sh, session, address))
  {
    /* Already existing, nothing todo, but this should not happen */
    GNUNET_break (0);
    return NULL;
  }
  s = find_empty_session_slot (sh);
  ar = GNUNET_new (struct GNUNET_ATS_AddressRecord);
  ar->sh = sh;
  ar->slot = s;
  ar->session = session;
  ar->address = GNUNET_HELLO_address_copy (address);
  GNUNET_array_grow (ar->ats,
                     ar->ats_count,
                     ats_count);
  memcpy (ar->ats,
          ats,
          ats_count * sizeof (struct GNUNET_ATS_Information));
  sh->session_array[s] = ar;
  send_add_address_message (sh, ar);
  return ar;
}


/**
 * An address was used to initiate a session.
 *
 * @param ar address record to update information for
 * @param session session handle
 */
void
GNUNET_ATS_address_add_session (struct GNUNET_ATS_AddressRecord *ar,
                                struct Session *session)
{
  GNUNET_break (NULL == ar->session);
  ar->session = session;
}


/**
 * A session was destroyed, disassociate it from the
 * given address record.  If this was an incoming
 * addess, destroy the address as well.
 *
 * @param ar address record to update information for
 * @param session session handle
 * @return #GNUNET_YES if the @a ar was destroyed because
 *                     it was an incoming address,
 *         #GNUNET_NO if the @ar was kept because we can
 *                    use it still to establish a new session
 */
int
GNUNET_ATS_address_del_session (struct GNUNET_ATS_AddressRecord *ar,
                                struct Session *session)
{
  GNUNET_break (session == ar->session);
  ar->session = NULL;
  GNUNET_break (GNUNET_NO == ar->in_use);
  if (GNUNET_HELLO_address_check_option (ar->address,
                                         GNUNET_HELLO_ADDRESS_INFO_INBOUND))
  {
    GNUNET_ATS_address_destroy (ar);
    return GNUNET_YES;
  }
  return GNUNET_NO;
}


/**
 * We have updated performance statistics for a given address.  Note
 * that this function can be called for addresses that are currently
 * in use as well as addresses that are valid but not actively in use.
 * Furthermore, the peer may not even be connected to us right now (in
 * which case the call may be ignored or the information may be stored
 * for later use).  Update bandwidth assignments.
 *
 * @param ar address record to update information for
 * @param ats performance data for the address
 * @param ats_count number of performance records in @a ats
 */
void
GNUNET_ATS_address_update (struct GNUNET_ATS_AddressRecord *ar,
                           const struct GNUNET_ATS_Information *ats,
                           uint32_t ats_count)
{
  struct GNUNET_ATS_SchedulingHandle *sh = ar->sh;
  struct GNUNET_MQ_Envelope *ev;
  struct AddressUpdateMessage *m;
  struct GNUNET_ATS_Information *am;
  size_t msize;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Adding address for peer `%s', plugin `%s', session %p id %u\n",
              GNUNET_i2s (&ar->address->peer),
              ar->address->transport_name,
              ar->session,
              ar->slot);
  GNUNET_array_grow (ar->ats,
                     ar->ats_count,
                     ats_count);
  memcpy (ar->ats,
          ats,
          ats_count * sizeof (struct GNUNET_ATS_Information));

  if (NULL == sh->mq)
    return; /* disconnected, skip for now */
  msize = ar->ats_count * sizeof (struct GNUNET_ATS_Information);
  ev = GNUNET_MQ_msg_extra (m, msize, GNUNET_MESSAGE_TYPE_ATS_ADDRESS_UPDATE);
  m->ats_count = htonl (ar->ats_count);
  m->peer = ar->address->peer;
  m->session_id = htonl (ar->slot);
  am = (struct GNUNET_ATS_Information *) &m[1];
  memcpy (am,
          ar->ats,
          ar->ats_count * sizeof (struct GNUNET_ATS_Information));
  GNUNET_MQ_send (sh->mq, ev);
}


/**
 * An address is now in use or not used any more.
 *
 * @param ar the address
 * @param in_use #GNUNET_YES if this address is now used, #GNUNET_NO
 * if address is not used any more
 */
void
GNUNET_ATS_address_set_in_use (struct GNUNET_ATS_AddressRecord *ar,
                               int in_use)
{
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Setting address used to %s for peer `%s', plugin `%s', session %p\n",
              (GNUNET_YES == in_use) ? "YES" : "NO",
              GNUNET_i2s (&ar->address->peer),
              ar->address->transport_name,
              ar->session);
  ar->in_use = in_use;
  if (NULL == ar->sh->mq)
    return;
  send_in_use_message (ar, in_use);
}


/**
 * An address got destroyed, stop using it as a valid address.
 *
 * @param ar address to destroy
 */
void
GNUNET_ATS_address_destroy (struct GNUNET_ATS_AddressRecord *ar)
{
  struct GNUNET_ATS_SchedulingHandle *sh = ar->sh;
  struct GNUNET_MQ_Envelope *ev;
  struct AddressDestroyedMessage *m;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Deleting address for peer `%s', plugin `%s', session %p\n",
              GNUNET_i2s (&ar->address->peer),
              ar->address->transport_name,
              ar->session);
  GNUNET_break (NULL == ar->session);
  ar->session = NULL;
  ar->in_destroy = GNUNET_YES;
  GNUNET_array_grow (ar->ats,
                     ar->ats_count,
                     0);
  if (NULL == sh->mq)
    return;
  ev = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_ATS_ADDRESS_DESTROYED);
  m->session_id = htonl (ar->slot);
  m->peer = ar->address->peer;
  GNUNET_MQ_send (sh->mq, ev);
}


/* end of ats_api_scheduling.c */