seti_api.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2012-2016, 2020 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_util_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_seti_service.h"
#include "seti.h"


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


struct GNUNET_SETI_Handle
{
  struct GNUNET_MQ_Handle *mq;

  struct GNUNET_SETI_OperationHandle *ops_head;

  struct GNUNET_SETI_OperationHandle *ops_tail;

  const struct GNUNET_CONFIGURATION_Handle *cfg;

  int destroy_requested;

  int invalid;

  uint16_t iteration_id;

};


struct GNUNET_SETI_Request
{
  uint32_t accept_id;

  int accepted;
};


struct GNUNET_SETI_OperationHandle
{
  GNUNET_SETI_ResultIterator result_cb;

  void *result_cls;

  struct GNUNET_SETI_Handle *set;

  struct GNUNET_MQ_Envelope *conclude_mqm;

  uint32_t *request_id_addr;

  struct GNUNET_SETI_OperationHandle *prev;

  struct GNUNET_SETI_OperationHandle *next;

  uint32_t request_id;

  int return_intersection;
};


struct GNUNET_SETI_ListenHandle
{
  struct GNUNET_MQ_Handle*mq;

  const struct GNUNET_CONFIGURATION_Handle *cfg;

  GNUNET_SETI_ListenCallback listen_cb;

  void *listen_cls;

  struct GNUNET_SCHEDULER_Task *reconnect_task;

  struct GNUNET_HashCode app_id;

  struct GNUNET_TIME_Relative reconnect_backoff;

};


static int
check_result (void *cls,
              const struct GNUNET_SETI_ResultMessage *msg)
{
  /* minimum size was already checked, everything else is OK! */
  return GNUNET_OK;
}


static void
handle_result (void *cls,
               const struct GNUNET_SETI_ResultMessage *msg)
{
  struct GNUNET_SETI_Handle *set = cls;
  struct GNUNET_SETI_OperationHandle *oh;
  struct GNUNET_SETI_Element e;
  enum GNUNET_SETI_Status result_status;
  int destroy_set;

  GNUNET_assert (NULL != set->mq);
  result_status = (enum GNUNET_SETI_Status) ntohs (msg->result_status);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Got result message with status %d\n",
       result_status);
  oh = GNUNET_MQ_assoc_get (set->mq,
                            ntohl (msg->request_id));
  if (NULL == oh)
  {
    /* 'oh' can be NULL if we canceled the operation, but the service
       did not get the cancel message yet. */
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Ignoring result from canceled operation\n");
    return;
  }

  switch (result_status)
  {
  case GNUNET_SETI_STATUS_ADD_LOCAL:
  case GNUNET_SETI_STATUS_DEL_LOCAL:
    e.data = &msg[1];
    e.size = ntohs (msg->header.size)
             - sizeof(struct GNUNET_SETI_ResultMessage);
    e.element_type = ntohs (msg->element_type);
    if (NULL != oh->result_cb)
      oh->result_cb (oh->result_cls,
                     &e,
                     GNUNET_ntohll (msg->current_size),
                     result_status);
    return;
  case GNUNET_SETI_STATUS_FAILURE:
  case GNUNET_SETI_STATUS_DONE:
    GNUNET_MQ_assoc_remove (set->mq,
                            ntohl (msg->request_id));
    GNUNET_CONTAINER_DLL_remove (set->ops_head,
                                 set->ops_tail,
                                 oh);
    /* Need to do this calculation _before_ the result callback,
       as IF the application still has a valid set handle, it
       may trigger destruction of the set during the callback. */
    destroy_set = (GNUNET_YES == set->destroy_requested) &&
                  (NULL == set->ops_head);
    if (NULL != oh->result_cb)
    {
      oh->result_cb (oh->result_cls,
                     NULL,
                     GNUNET_ntohll (msg->current_size),
                     result_status);
    }
    else
    {
      LOG (GNUNET_ERROR_TYPE_DEBUG,
           "No callback for final status\n");
    }
    if (destroy_set)
      GNUNET_SETI_destroy (set);
    GNUNET_free (oh);
    return;
  }
}


static void
set_operation_destroy (struct GNUNET_SETI_OperationHandle *oh)
{
  struct GNUNET_SETI_Handle *set = oh->set;
  struct GNUNET_SETI_OperationHandle *h_assoc;

  if (NULL != oh->conclude_mqm)
    GNUNET_MQ_discard (oh->conclude_mqm);
  /* is the operation already commited? */
  if (NULL != set)
  {
    GNUNET_CONTAINER_DLL_remove (set->ops_head,
                                 set->ops_tail,
                                 oh);
    h_assoc = GNUNET_MQ_assoc_remove (set->mq,
                                      oh->request_id);
    GNUNET_assert ((NULL == h_assoc) ||
                   (h_assoc == oh));
  }
  GNUNET_free (oh);
}


void
GNUNET_SETI_operation_cancel (struct GNUNET_SETI_OperationHandle *oh)
{
  struct GNUNET_SETI_Handle *set = oh->set;
  struct GNUNET_SETI_CancelMessage *m;
  struct GNUNET_MQ_Envelope *mqm;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Cancelling SET operation\n");
  if (NULL != set)
  {
    mqm = GNUNET_MQ_msg (m, GNUNET_MESSAGE_TYPE_SETI_CANCEL);
    m->request_id = htonl (oh->request_id);
    GNUNET_MQ_send (set->mq, mqm);
  }
  set_operation_destroy (oh);
  if ((NULL != set) &&
      (GNUNET_YES == set->destroy_requested) &&
      (NULL == set->ops_head))
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Destroying set after operation cancel\n");
    GNUNET_SETI_destroy (set);
  }
}


static void
handle_client_set_error (void *cls,
                         enum GNUNET_MQ_Error error)
{
  struct GNUNET_SETI_Handle *set = cls;

  LOG (GNUNET_ERROR_TYPE_ERROR,
       "Handling client set error %d\n",
       error);
  while (NULL != set->ops_head)
  {
    if ((NULL != set->ops_head->result_cb) &&
        (GNUNET_NO == set->destroy_requested))
      set->ops_head->result_cb (set->ops_head->result_cls,
                                NULL,
                                0,
                                GNUNET_SETI_STATUS_FAILURE);
    set_operation_destroy (set->ops_head);
  }
  set->invalid = GNUNET_YES;
}


struct GNUNET_SETI_Handle *
GNUNET_SETI_create (const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  struct GNUNET_SETI_Handle *set = GNUNET_new (struct GNUNET_SETI_Handle);
  struct GNUNET_MQ_MessageHandler mq_handlers[] = {
    GNUNET_MQ_hd_var_size (result,
                           GNUNET_MESSAGE_TYPE_SETI_RESULT,
                           struct GNUNET_SETI_ResultMessage,
                           set),
    GNUNET_MQ_handler_end ()
  };
  struct GNUNET_MQ_Envelope *mqm;
  struct GNUNET_SETI_CreateMessage *create_msg;

  set->cfg = cfg;
  set->mq = GNUNET_CLIENT_connect (cfg,
                                   "seti",
                                   mq_handlers,
                                   &handle_client_set_error,
                                   set);
  if (NULL == set->mq)
  {
    GNUNET_free (set);
    return NULL;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Creating new intersection set\n");
  mqm = GNUNET_MQ_msg (create_msg,
                       GNUNET_MESSAGE_TYPE_SETI_CREATE);
  GNUNET_MQ_send (set->mq,
                  mqm);
  return set;
}


int
GNUNET_SETI_add_element (struct GNUNET_SETI_Handle *set,
                         const struct GNUNET_SETI_Element *element,
                         GNUNET_SCHEDULER_TaskCallback cb,
                         void *cb_cls)
{
  struct GNUNET_MQ_Envelope *mqm;
  struct GNUNET_SETI_ElementMessage *msg;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "adding element of type %u to set %p\n",
       (unsigned int) element->element_type,
       set);
  if (GNUNET_YES == set->invalid)
  {
    if (NULL != cb)
      cb (cb_cls);
    return GNUNET_SYSERR;
  }
  mqm = GNUNET_MQ_msg_extra (msg,
                             element->size,
                             GNUNET_MESSAGE_TYPE_SETI_ADD);
  msg->element_type = htons (element->element_type);
  GNUNET_memcpy (&msg[1],
                 element->data,
                 element->size);
  GNUNET_MQ_notify_sent (mqm,
                         cb,
                         cb_cls);
  GNUNET_MQ_send (set->mq,
                  mqm);
  return GNUNET_OK;
}


void
GNUNET_SETI_destroy (struct GNUNET_SETI_Handle *set)
{
  /* destroying set while iterator is active is currently
     not supported; we should expand the API to allow
     clients to explicitly cancel the iteration! */
  if ((NULL != set->ops_head) ||
      (GNUNET_SYSERR == set->destroy_requested))
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Set operations are pending, delaying set destruction\n");
    set->destroy_requested = GNUNET_YES;
    return;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Really destroying set\n");
  if (NULL != set->mq)
  {
    GNUNET_MQ_destroy (set->mq);
    set->mq = NULL;
  }
  GNUNET_free (set);
}


struct GNUNET_SETI_OperationHandle *
GNUNET_SETI_prepare (const struct GNUNET_PeerIdentity *other_peer,
                     const struct GNUNET_HashCode *app_id,
                     const struct GNUNET_MessageHeader *context_msg,
                     const struct GNUNET_SETI_Option options[],
                     GNUNET_SETI_ResultIterator result_cb,
                     void *result_cls)
{
  struct GNUNET_MQ_Envelope *mqm;
  struct GNUNET_SETI_OperationHandle *oh;
  struct GNUNET_SETI_EvaluateMessage *msg;

  oh = GNUNET_new (struct GNUNET_SETI_OperationHandle);
  oh->result_cb = result_cb;
  oh->result_cls = result_cls;
  mqm = GNUNET_MQ_msg_nested_mh (msg,
                                 GNUNET_MESSAGE_TYPE_SETI_EVALUATE,
                                 context_msg);
  msg->app_id = *app_id;
  msg->target_peer = *other_peer;
  for (const struct GNUNET_SETI_Option *opt = options;
       GNUNET_SETI_OPTION_END != opt->type;
       opt++)
  {
    switch (opt->type)
    {
    case GNUNET_SETI_OPTION_RETURN_INTERSECTION:
      msg->return_intersection = htonl (GNUNET_YES);
      break;
    default:
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "Option with type %d not recognized\n",
           (int) opt->type);
    }
  }
  oh->conclude_mqm = mqm;
  oh->request_id_addr = &msg->request_id;
  return oh;
}


static void
listen_connect (void *cls);


static int
check_request (void *cls,
               const struct GNUNET_SETI_RequestMessage *msg)
{
  const struct GNUNET_MessageHeader *context_msg;

  if (ntohs (msg->header.size) == sizeof(*msg))
    return GNUNET_OK; /* no context message is OK */
  context_msg = GNUNET_MQ_extract_nested_mh (msg);
  if (NULL == context_msg)
  {
    /* malformed context message is NOT ok */
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}


static void
handle_request (void *cls,
                const struct GNUNET_SETI_RequestMessage *msg)
{
  struct GNUNET_SETI_ListenHandle *lh = cls;
  struct GNUNET_SETI_Request req;
  const struct GNUNET_MessageHeader *context_msg;
  struct GNUNET_MQ_Envelope *mqm;
  struct GNUNET_SETI_RejectMessage *rmsg;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Processing incoming operation request with id %u\n",
       ntohl (msg->accept_id));
  /* we got another valid request => reset the backoff */
  lh->reconnect_backoff = GNUNET_TIME_UNIT_MILLISECONDS;
  req.accept_id = ntohl (msg->accept_id);
  req.accepted = GNUNET_NO;
  context_msg = GNUNET_MQ_extract_nested_mh (msg);
  /* calling #GNUNET_SETI_accept() in the listen cb will set req->accepted */
  lh->listen_cb (lh->listen_cls,
                 &msg->peer_id,
                 context_msg,
                 &req);
  if (GNUNET_YES == req.accepted)
    return; /* the accept-case is handled in #GNUNET_SETI_accept() */
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Rejected request %u\n",
       ntohl (msg->accept_id));
  mqm = GNUNET_MQ_msg (rmsg,
                       GNUNET_MESSAGE_TYPE_SETI_REJECT);
  rmsg->accept_reject_id = msg->accept_id;
  GNUNET_MQ_send (lh->mq,
                  mqm);
}


static void
handle_client_listener_error (void *cls,
                              enum GNUNET_MQ_Error error)
{
  struct GNUNET_SETI_ListenHandle *lh = cls;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Listener broke down (%d), re-connecting\n",
       (int) error);
  GNUNET_MQ_destroy (lh->mq);
  lh->mq = NULL;
  lh->reconnect_task = GNUNET_SCHEDULER_add_delayed (lh->reconnect_backoff,
                                                     &listen_connect,
                                                     lh);
  lh->reconnect_backoff = GNUNET_TIME_STD_BACKOFF (lh->reconnect_backoff);
}


static void
listen_connect (void *cls)
{
  struct GNUNET_SETI_ListenHandle *lh = cls;
  struct GNUNET_MQ_MessageHandler mq_handlers[] = {
    GNUNET_MQ_hd_var_size (request,
                           GNUNET_MESSAGE_TYPE_SETI_REQUEST,
                           struct GNUNET_SETI_RequestMessage,
                           lh),
    GNUNET_MQ_handler_end ()
  };
  struct GNUNET_MQ_Envelope *mqm;
  struct GNUNET_SETI_ListenMessage *msg;

  lh->reconnect_task = NULL;
  GNUNET_assert (NULL == lh->mq);
  lh->mq = GNUNET_CLIENT_connect (lh->cfg,
                                  "seti",
                                  mq_handlers,
                                  &handle_client_listener_error,
                                  lh);
  if (NULL == lh->mq)
    return;
  mqm = GNUNET_MQ_msg (msg, GNUNET_MESSAGE_TYPE_SETI_LISTEN);
  msg->app_id = lh->app_id;
  GNUNET_MQ_send (lh->mq,
                  mqm);
}


struct GNUNET_SETI_ListenHandle *
GNUNET_SETI_listen (const struct GNUNET_CONFIGURATION_Handle *cfg,
                    const struct GNUNET_HashCode *app_id,
                    GNUNET_SETI_ListenCallback listen_cb,
                    void *listen_cls)
{
  struct GNUNET_SETI_ListenHandle *lh;

  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Starting listener for app %s\n",
       GNUNET_h2s (app_id));
  lh = GNUNET_new (struct GNUNET_SETI_ListenHandle);
  lh->listen_cb = listen_cb;
  lh->listen_cls = listen_cls;
  lh->cfg = cfg;
  lh->app_id = *app_id;
  lh->reconnect_backoff = GNUNET_TIME_UNIT_MILLISECONDS;
  listen_connect (lh);
  if (NULL == lh->mq)
  {
    GNUNET_free (lh);
    return NULL;
  }
  return lh;
}


void
GNUNET_SETI_listen_cancel (struct GNUNET_SETI_ListenHandle *lh)
{
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Canceling listener %s\n",
       GNUNET_h2s (&lh->app_id));
  if (NULL != lh->mq)
  {
    GNUNET_MQ_destroy (lh->mq);
    lh->mq = NULL;
  }
  if (NULL != lh->reconnect_task)
  {
    GNUNET_SCHEDULER_cancel (lh->reconnect_task);
    lh->reconnect_task = NULL;
  }
  GNUNET_free (lh);
}


struct GNUNET_SETI_OperationHandle *
GNUNET_SETI_accept (struct GNUNET_SETI_Request *request,
                    const struct GNUNET_SETI_Option options[],
                    GNUNET_SETI_ResultIterator result_cb,
                    void *result_cls)
{
  struct GNUNET_MQ_Envelope *mqm;
  struct GNUNET_SETI_OperationHandle *oh;
  struct GNUNET_SETI_AcceptMessage *msg;

  GNUNET_assert (GNUNET_NO == request->accepted);
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Client accepts set intersection operation with id %u\n",
       request->accept_id);
  request->accepted = GNUNET_YES;
  mqm = GNUNET_MQ_msg (msg,
                       GNUNET_MESSAGE_TYPE_SETI_ACCEPT);
  msg->accept_reject_id = htonl (request->accept_id);
  oh = GNUNET_new (struct GNUNET_SETI_OperationHandle);
  oh->result_cb = result_cb;
  oh->result_cls = result_cls;
  oh->conclude_mqm = mqm;
  oh->request_id_addr = &msg->request_id;
  for (const struct GNUNET_SETI_Option *opt = options;
       GNUNET_SETI_OPTION_END != opt->type;
       opt++)
  {
    switch (opt->type)
    {
    case GNUNET_SETI_OPTION_RETURN_INTERSECTION:
      oh->return_intersection = GNUNET_YES;
      msg->return_intersection = htonl (GNUNET_YES);
      break;
    default:
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "Option with type %d not recognized\n",
           (int) opt->type);
    }
  }
  return oh;
}


int
GNUNET_SETI_commit (struct GNUNET_SETI_OperationHandle *oh,
                    struct GNUNET_SETI_Handle *set)
{
  if (NULL != oh->set)
  {
    /* Some other set was already committed for this
     * operation, there is a logic bug in the client of this API */
    GNUNET_break (0);
    return GNUNET_OK;
  }
  GNUNET_assert (NULL != set);
  if (GNUNET_YES == set->invalid)
    return GNUNET_SYSERR;
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Client commits to SET\n");
  GNUNET_assert (NULL != oh->conclude_mqm);
  oh->set = set;
  GNUNET_CONTAINER_DLL_insert (set->ops_head,
                               set->ops_tail,
                               oh);
  oh->request_id = GNUNET_MQ_assoc_add (set->mq,
                                        oh);
  *oh->request_id_addr = htonl (oh->request_id);
  GNUNET_MQ_send (set->mq,
                  oh->conclude_mqm);
  oh->conclude_mqm = NULL;
  oh->request_id_addr = NULL;
  return GNUNET_OK;
}


void
GNUNET_SETI_element_hash (const struct GNUNET_SETI_Element *element,
                          struct GNUNET_HashCode *ret_hash)
{
  struct GNUNET_HashContext *ctx = GNUNET_CRYPTO_hash_context_start ();

  /* It's not guaranteed that the element data is always after the element header,
     so we need to hash the chunks separately. */
  GNUNET_CRYPTO_hash_context_read (ctx,
                                   &element->size,
                                   sizeof(uint16_t));
  GNUNET_CRYPTO_hash_context_read (ctx,
                                   &element->element_type,
                                   sizeof(uint16_t));
  GNUNET_CRYPTO_hash_context_read (ctx,
                                   element->data,
                                   element->size);
  GNUNET_CRYPTO_hash_context_finish (ctx,
                                     ret_hash);
}


/* end of seti_api.c */