ats_api_scheduling.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2010-2015 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
#include "platform.h"
#include "gnunet_ats_service.h"
#include "ats.h"

#define INTERFACE_PROCESSING_INTERVAL GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_MINUTES, 2)

#define LOG(kind, ...) GNUNET_log_from(kind, "ats-scheduling-api", __VA_ARGS__)

#define NOT_FOUND 0


struct GNUNET_ATS_AddressRecord {
  struct GNUNET_ATS_SchedulingHandle *sh;

  struct GNUNET_HELLO_Address *address;

  struct GNUNET_ATS_Session *session;

  struct GNUNET_ATS_PropertiesNBO properties;

  uint32_t slot;

  int in_destroy;
};


struct GNUNET_ATS_SchedulingHandle {
  const struct GNUNET_CONFIGURATION_Handle *cfg;

  GNUNET_ATS_AddressSuggestionCallback suggest_cb;

  void *suggest_cb_cls;

  struct GNUNET_MQ_Handle *mq;

  struct GNUNET_ATS_AddressRecord **session_array;

  struct GNUNET_SCHEDULER_Task *task;

  struct GNUNET_TIME_Relative backoff;

  unsigned int session_array_size;
};


static void
reconnect(struct GNUNET_ATS_SchedulingHandle *sh);


static void
reconnect_task(void *cls)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;

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


static void
force_reconnect(struct GNUNET_ATS_SchedulingHandle *sh)
{
  if (NULL != sh->mq)
    {
      GNUNET_MQ_destroy(sh->mq);
      sh->mq = NULL;
    }
  sh->suggest_cb(sh->suggest_cb_cls,
                 NULL, NULL, NULL,
                 GNUNET_BANDWIDTH_ZERO,
                 GNUNET_BANDWIDTH_ZERO);
  sh->backoff = GNUNET_TIME_STD_BACKOFF(sh->backoff);
  sh->task = GNUNET_SCHEDULER_add_delayed(sh->backoff,
                                          &reconnect_task,
                                          sh);
}


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 != GNUNET_memcmp(peer,
                         &ar->address->peer))
    {
      GNUNET_break(0);
      return NULL;
    }
  return ar;
}


static uint32_t
find_empty_session_slot(struct GNUNET_ATS_SchedulingHandle *sh)
{
  static uint32_t off;
  uint32_t i;

  GNUNET_assert(0 != sh->session_array_size);
  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;
}


static uint32_t
find_session_id(struct GNUNET_ATS_SchedulingHandle *sh,
                struct GNUNET_ATS_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]) &&
        (GNUNET_NO == sh->session_array[i]->in_destroy) &&
        ((session == sh->session_array[i]->session) ||
         (NULL == sh->session_array[i]->session)) &&
        (0 == GNUNET_memcmp(&address->peer,
                            &sh->session_array[i]->address->peer)) &&
        (0 == GNUNET_HELLO_address_cmp(address,
                                       sh->session_array[i]->address)))
      return i;
  return NOT_FOUND;
}


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;
}


static void
handle_ats_session_release(void *cls,
                           const struct GNUNET_ATS_SessionReleaseMessage *srm)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;

  /* 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));
}


static void
handle_ats_address_suggestion(void *cls,
                              const struct AddressSuggestionMessage *m)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;
  struct GNUNET_ATS_AddressRecord *ar;
  uint32_t session_id;

  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, unless BW is 0,
         in that case signal 'disconnect' via BW 0 */
      if ((0 == ntohl(m->bandwidth_out.value__)) &&
          (0 == ntohl(m->bandwidth_in.value__)))
        {
          LOG(GNUNET_ERROR_TYPE_DEBUG,
              "ATS suggests disconnect from peer `%s' with BW %u/%u\n",
              GNUNET_i2s(&ar->address->peer),
              (unsigned int)ntohl(m->bandwidth_out.value__),
              (unsigned int)ntohl(m->bandwidth_in.value__));
          sh->suggest_cb(sh->suggest_cb_cls,
                         &m->peer,
                         NULL,
                         NULL,
                         m->bandwidth_out,
                         m->bandwidth_in);
        }
      return;
    }
  if ((NULL == ar->session) &&
      (GNUNET_HELLO_address_check_option(ar->address,
                                         GNUNET_HELLO_ADDRESS_INFO_INBOUND)))
    {
      GNUNET_break(0);
      return;
    }
  sh->backoff = GNUNET_TIME_UNIT_ZERO;
  LOG(GNUNET_ERROR_TYPE_DEBUG,
      "ATS suggests address slot %u for peer `%s' using plugin %s\n",
      ar->slot,
      GNUNET_i2s(&ar->address->peer),
      ar->address->transport_name);
  sh->suggest_cb(sh->suggest_cb_cls,
                 &m->peer,
                 ar->address,
                 ar->session,
                 m->bandwidth_out,
                 m->bandwidth_in);
}


static void
error_handler(void *cls,
              enum GNUNET_MQ_Error error)
{
  struct GNUNET_ATS_SchedulingHandle *sh = cls;

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


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;
  char *pm;
  size_t namelen;
  size_t msize;

  if (NULL == sh->mq)
    return; /* disconnected, skip for now */
  GNUNET_break(GNUNET_NT_UNSPECIFIED != ar->properties.scope);
  namelen = strlen(ar->address->transport_name) + 1;
  msize = ar->address->address_length + namelen;
  ev = GNUNET_MQ_msg_extra(m, msize, GNUNET_MESSAGE_TYPE_ATS_ADDRESS_ADD);
  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);
  m->properties = ar->properties;

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


static void
reconnect(struct GNUNET_ATS_SchedulingHandle *sh)
{
  struct GNUNET_MQ_MessageHandler handlers[] = {
    GNUNET_MQ_hd_fixed_size(ats_session_release,
                            GNUNET_MESSAGE_TYPE_ATS_SESSION_RELEASE,
                            struct GNUNET_ATS_SessionReleaseMessage,
                            sh),
    GNUNET_MQ_hd_fixed_size(ats_address_suggestion,
                            GNUNET_MESSAGE_TYPE_ATS_ADDRESS_SUGGESTION,
                            struct AddressSuggestionMessage,
                            sh),
    GNUNET_MQ_handler_end()
  };
  struct GNUNET_MQ_Envelope *ev;
  struct ClientStartMessage *init;
  unsigned int i;
  struct GNUNET_ATS_AddressRecord *ar;

  GNUNET_assert(NULL == sh->mq);
  sh->mq = GNUNET_CLIENT_connect(sh->cfg,
                                 "ats",
                                 handlers,
                                 &error_handler,
                                 sh);
  if (NULL == sh->mq)
    {
      GNUNET_break(0);
      force_reconnect(sh);
      return;
    }
  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 (NULL == sh->mq)
        return;
    }
}


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);
  reconnect(sh);
  return sh;
}


void
GNUNET_ATS_scheduling_done(struct GNUNET_ATS_SchedulingHandle *sh)
{
  struct GNUNET_ATS_AddressRecord *ar;
  unsigned int i;

  if (NULL != sh->mq)
    {
      GNUNET_MQ_destroy(sh->mq);
      sh->mq = NULL;
    }
  if (NULL != sh->task)
    {
      GNUNET_SCHEDULER_cancel(sh->task);
      sh->task = NULL;
    }
  for (i = 0; i < sh->session_array_size; i++)
    {
      if (NULL != (ar = sh->session_array[i]))
        {
          GNUNET_HELLO_address_free(ar->address);
          GNUNET_free(ar);
          sh->session_array[i] = NULL;
        }
    }
  GNUNET_array_grow(sh->session_array,
                    sh->session_array_size,
                    0);
  GNUNET_free(sh);
}


struct GNUNET_ATS_AddressRecord *
GNUNET_ATS_address_add(struct GNUNET_ATS_SchedulingHandle *sh,
                       const struct GNUNET_HELLO_Address *address,
                       struct GNUNET_ATS_Session *session,
                       const struct GNUNET_ATS_Properties *prop)
{
  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;
    }
  GNUNET_break(GNUNET_NT_UNSPECIFIED != prop->scope);
  namelen = strlen(address->transport_name) + 1;
  msize = address->address_length + namelen;
  if ((msize + sizeof(struct AddressUpdateMessage) >= GNUNET_MAX_MESSAGE_SIZE) ||
      (address->address_length >= GNUNET_MAX_MESSAGE_SIZE) ||
      (namelen >= GNUNET_MAX_MESSAGE_SIZE))
    {
      /* 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_ATS_properties_hton(&ar->properties,
                             prop);
  sh->session_array[s] = ar;
  send_add_address_message(sh, ar);
  return ar;
}


void
GNUNET_ATS_address_add_session(struct GNUNET_ATS_AddressRecord *ar,
                               struct GNUNET_ATS_Session *session)
{
  GNUNET_break(NULL == ar->session);
  ar->session = session;
}


int
GNUNET_ATS_address_del_session(struct GNUNET_ATS_AddressRecord *ar,
                               struct GNUNET_ATS_Session *session)
{
  GNUNET_assert(session == ar->session);
  ar->session = NULL;
  if (GNUNET_HELLO_address_check_option(ar->address,
                                        GNUNET_HELLO_ADDRESS_INFO_INBOUND))
    {
      GNUNET_ATS_address_destroy(ar);
      return GNUNET_YES;
    }
  return GNUNET_NO;
}


void
GNUNET_ATS_address_update(struct GNUNET_ATS_AddressRecord *ar,
                          const struct GNUNET_ATS_Properties *prop)
{
  struct GNUNET_ATS_SchedulingHandle *sh = ar->sh;
  struct GNUNET_MQ_Envelope *ev;
  struct AddressUpdateMessage *m;

  LOG(GNUNET_ERROR_TYPE_DEBUG,
      "Updating address for peer `%s', plugin `%s', session %p slot %u\n",
      GNUNET_i2s(&ar->address->peer),
      ar->address->transport_name,
      ar->session,
      ar->slot);
  GNUNET_break(GNUNET_NT_UNSPECIFIED != prop->scope);
  GNUNET_ATS_properties_hton(&ar->properties,
                             prop);
  if (NULL == sh->mq)
    return; /* disconnected, skip for now */
  ev = GNUNET_MQ_msg(m, GNUNET_MESSAGE_TYPE_ATS_ADDRESS_UPDATE);
  m->session_id = htonl(ar->slot);
  m->peer = ar->address->peer;
  m->properties = ar->properties;
  GNUNET_MQ_send(sh->mq,
                 ev);
}


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;

  LOG(GNUNET_ERROR_TYPE_DEBUG,
      "Deleting address for peer `%s', plugin `%s', slot %u session %p\n",
      GNUNET_i2s(&ar->address->peer),
      ar->address->transport_name,
      ar->slot,
      ar->session);
  GNUNET_break(NULL == ar->session);
  ar->session = NULL;
  ar->in_destroy = GNUNET_YES;
  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 */