peerinfo_api.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2001-2014 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 "peerinfo.h"
 
#define LOG(kind, ...) GNUNET_log_from (kind, "peerinfo-api", __VA_ARGS__)
 
 
struct GNUNET_PEERINFO_IteratorContext
{
  struct GNUNET_PEERINFO_IteratorContext *next;
 
  struct GNUNET_PEERINFO_IteratorContext *prev;
 
  struct GNUNET_PEERINFO_Handle *h;
 
  GNUNET_PEERINFO_Processor callback;
 
  void *callback_cls;
 
  struct GNUNET_PeerIdentity peer;
 
  int have_peer;
 
  int include_friend_only;
};
 
 
struct GNUNET_PEERINFO_Handle
{
  const struct GNUNET_CONFIGURATION_Handle *cfg;
 
  struct GNUNET_MQ_Handle *mq;
 
  struct GNUNET_PEERINFO_IteratorContext *ic_head;
 
  struct GNUNET_PEERINFO_IteratorContext *ic_tail;
 
  struct GNUNET_SCHEDULER_Task *r_task;
};
 
 
static void
reconnect (struct GNUNET_PEERINFO_Handle *h);
 
 
struct GNUNET_PEERINFO_Handle *
GNUNET_PEERINFO_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  struct GNUNET_PEERINFO_Handle *h;
 
  h = GNUNET_new (struct GNUNET_PEERINFO_Handle);
  h->cfg = cfg;
  reconnect (h);
  if (NULL == h->mq)
  {
    GNUNET_free (h);
    return NULL;
  }
  return h;
}
 
 
void
GNUNET_PEERINFO_disconnect (struct GNUNET_PEERINFO_Handle *h)
{
  struct GNUNET_PEERINFO_IteratorContext *ic;
 
  while (NULL != (ic = h->ic_head))
  {
    GNUNET_CONTAINER_DLL_remove (h->ic_head,
                                 h->ic_tail,
                                 ic);
    GNUNET_free (ic);
  }
  if (NULL != h->mq)
  {
    GNUNET_MQ_destroy (h->mq);
    h->mq = NULL;
  }
  if (NULL != h->r_task)
  {
    GNUNET_SCHEDULER_cancel (h->r_task);
    h->r_task = NULL;
  }
  GNUNET_free (h);
}
 
 
static void
reconnect_task (void *cls)
{
  struct GNUNET_PEERINFO_Handle *h = cls;
 
  h->r_task = NULL;
  reconnect (h);
}
 
 
static void
do_reconnect (struct GNUNET_PEERINFO_Handle *h)
{
  struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
 
  GNUNET_MQ_destroy (h->mq);
  h->mq = NULL;
  if (NULL != ic)
  {
    GNUNET_CONTAINER_DLL_remove (h->ic_head,
                                 h->ic_tail,
                                 ic);
    if (NULL != ic->callback)
      ic->callback (ic->callback_cls,
                    NULL,
                    NULL,
                    _ ("Failed to receive response from `PEERINFO' service."));
    GNUNET_free (ic);
  }
  h->r_task = GNUNET_SCHEDULER_add_now (&reconnect_task,
                                        h);
}
 
 
static void
mq_error_handler (void *cls,
                  enum GNUNET_MQ_Error error)
{
  struct GNUNET_PEERINFO_Handle *h = cls;
 
  do_reconnect (h);
}
 
 
static int
check_info (void *cls,
            const struct InfoMessage *im)
{
  struct GNUNET_PEERINFO_Handle *h = cls;
  struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
  uint16_t ms = ntohs (im->header.size) - sizeof(*im);
 
  if (0 != ntohl (im->reserved))
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  if (NULL == ic)
  {
    /* didn't expect a response, bad */
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  if ((GNUNET_YES == ic->have_peer) &&
      (0 != GNUNET_memcmp (&ic->peer,
                           &im->peer)))
  {
    /* bogus message (from a different iteration call?); out of sequence! */
    LOG (GNUNET_ERROR_TYPE_ERROR,
         "Received HELLO for peer `%s', expected peer `%s'\n",
         GNUNET_i2s (&im->peer),
         GNUNET_i2s (&ic->peer));
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  if (ms > sizeof(struct GNUNET_MessageHeader))
  {
    const struct GNUNET_HELLO_Message *hello;
    struct GNUNET_PeerIdentity id;
 
    hello = (const struct GNUNET_HELLO_Message *) &im[1];
    if (ms != GNUNET_HELLO_size (hello))
    {
      /* malformed message */
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
    if (GNUNET_OK !=
        GNUNET_HELLO_get_id (hello,
                             &id))
    {
      /* malformed message */
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
    if (0 != GNUNET_memcmp (&im->peer,
                            &id))
    {
      /* malformed message */
      GNUNET_break (0);
      return GNUNET_SYSERR;
    }
  }
  else if (0 != ms)
  {
    /* malformed message */
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}
 
 
static void
handle_info (void *cls,
             const struct InfoMessage *im)
{
  struct GNUNET_PEERINFO_Handle *h = cls;
  struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
  const struct GNUNET_HELLO_Message *hello = NULL;
  uint16_t ms;
 
  ms = ntohs (im->header.size);
  if (ms > sizeof(struct InfoMessage))
    hello = (const struct GNUNET_HELLO_Message *) &im[1];
  if (NULL != ic->callback)
    ic->callback (ic->callback_cls,
                  &im->peer,
                  hello,
                  NULL);
}
 
 
static void
send_ic_request (struct GNUNET_PEERINFO_Handle *h)
{
  struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
  struct GNUNET_MQ_Envelope *env;
  struct ListAllPeersMessage *lapm;
  struct ListPeerMessage *lpm;
 
  if (NULL == ic)
  {
    GNUNET_break (0);
    return;
  }
  if (NULL == h->mq)
  {
    GNUNET_break (0);
    return;
  }
  if (GNUNET_NO == ic->have_peer)
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Requesting list of peers from PEERINFO service\n");
    env = GNUNET_MQ_msg (lapm,
                         GNUNET_MESSAGE_TYPE_PEERINFO_GET_ALL);
    lapm->include_friend_only = htonl (ic->include_friend_only);
  }
  else
  {
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "Requesting information on peer `%s' from PEERINFO service\n",
         GNUNET_i2s (&ic->peer));
    env = GNUNET_MQ_msg (lpm,
                         GNUNET_MESSAGE_TYPE_PEERINFO_GET);
    lpm->include_friend_only = htonl (ic->include_friend_only);
    lpm->peer = ic->peer;
  }
  GNUNET_MQ_send (h->mq,
                  env);
}
 
 
static void
handle_end_iteration (void *cls,
                      const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_PEERINFO_Handle *h = cls;
  struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head;
 
  if (NULL == ic)
  {
    /* didn't expect a response, reconnect */
    GNUNET_break (0);
    reconnect (h);
    return;
  }
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Received end of list of peers from PEERINFO service\n");
  GNUNET_CONTAINER_DLL_remove (h->ic_head,
                               h->ic_tail,
                               ic);
  if (NULL != h->ic_head)
    send_ic_request (h);
  if (NULL != ic->callback)
    ic->callback (ic->callback_cls,
                  NULL,
                  NULL,
                  NULL);
  GNUNET_free (ic);
}
 
 
static void
reconnect (struct GNUNET_PEERINFO_Handle *h)
{
  struct GNUNET_MQ_MessageHandler handlers[] = {
    GNUNET_MQ_hd_var_size (info,
                           GNUNET_MESSAGE_TYPE_PEERINFO_INFO,
                           struct InfoMessage,
                           h),
    GNUNET_MQ_hd_fixed_size (end_iteration,
                             GNUNET_MESSAGE_TYPE_PEERINFO_INFO_END,
                             struct GNUNET_MessageHeader,
                             h),
    GNUNET_MQ_handler_end ()
  };
 
  if (NULL != h->r_task)
  {
    GNUNET_SCHEDULER_cancel (h->r_task);
    h->r_task = NULL;
  }
  if (NULL != h->mq)
  {
    GNUNET_MQ_destroy (h->mq);
    h->mq = NULL;
  }
  h->mq = GNUNET_CLIENT_connect (h->cfg,
                                 "peerinfo",
                                 handlers,
                                 &mq_error_handler,
                                 h);
  if (NULL != h->ic_head)
    send_ic_request (h);
}
 
 
struct GNUNET_PEERINFO_IteratorContext *
GNUNET_PEERINFO_iterate (struct GNUNET_PEERINFO_Handle *h,
                         int include_friend_only,
                         const struct GNUNET_PeerIdentity *peer,
                         GNUNET_PEERINFO_Processor callback,
                         void *callback_cls)
{
  struct GNUNET_PEERINFO_IteratorContext *ic;
 
  ic = GNUNET_new (struct GNUNET_PEERINFO_IteratorContext);
  ic->h = h;
  ic->include_friend_only = include_friend_only;
  ic->callback = callback;
  ic->callback_cls = callback_cls;
  if (NULL != peer)
  {
    ic->have_peer = GNUNET_YES;
    ic->peer = *peer;
  }
  GNUNET_CONTAINER_DLL_insert_tail (h->ic_head,
                                    h->ic_tail,
                                    ic);
  if (h->ic_head == ic)
    send_ic_request (h);
  return ic;
}
 
 
void
GNUNET_PEERINFO_iterate_cancel (struct GNUNET_PEERINFO_IteratorContext *ic)
{
  struct GNUNET_PEERINFO_Handle *h = ic->h;
 
  ic->callback = NULL;
  if (ic == h->ic_head)
    return;
  GNUNET_CONTAINER_DLL_remove (h->ic_head,
                               h->ic_tail,
                               ic);
  GNUNET_free (ic);
}
 
 
struct GNUNET_MQ_Envelope *
GNUNET_PEERINFO_add_peer (struct GNUNET_PEERINFO_Handle *h,
                          const struct GNUNET_HELLO_Message *hello,
                          GNUNET_SCHEDULER_TaskCallback cont,
                          void *cont_cls)
{
  struct GNUNET_MQ_Envelope *env;
  struct GNUNET_PeerIdentity peer;
 
  if (NULL == h->mq)
    return NULL;
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_HELLO_get_id (hello,
                                      &peer));
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Adding peer `%s' to PEERINFO database\n",
       GNUNET_i2s (&peer));
  env = GNUNET_MQ_msg_copy ((const struct GNUNET_MessageHeader *) hello);
  if (NULL != cont)
    GNUNET_MQ_notify_sent (env,
                           cont,
                           cont_cls);
  GNUNET_MQ_send (h->mq,
                  env);
  return env;
}
 
 
/* end of peerinfo_api.c */