transport_api_monitor_peers.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2009-2014, 2016 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_arm_service.h"
#include "gnunet_hello_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_transport_service.h"
#include "transport.h"
 
struct GNUNET_TRANSPORT_PeerMonitoringContext
{
  GNUNET_TRANSPORT_PeerIterateCallback cb;
 
  void *cb_cls;
 
  struct GNUNET_MQ_Handle *mq;
 
  const struct GNUNET_CONFIGURATION_Handle *cfg;
 
  struct GNUNET_TIME_Relative backoff;
 
  struct GNUNET_SCHEDULER_Task *reconnect_task;
 
  struct GNUNET_PeerIdentity peer;
 
  int one_shot;
};
 
 
int
GNUNET_TRANSPORT_is_connected (enum GNUNET_TRANSPORT_PeerState state)
{
  switch (state)
  {
  case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
  case GNUNET_TRANSPORT_PS_INIT_ATS:
  case GNUNET_TRANSPORT_PS_SYN_SENT:
  case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
  case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
    return GNUNET_NO;
 
  case GNUNET_TRANSPORT_PS_CONNECTED:
  case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
  case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
  case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
    return GNUNET_YES;
 
  case GNUNET_TRANSPORT_PS_DISCONNECT:
  case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
    return GNUNET_NO;
 
  default:
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unhandled state `%s'\n",
                GNUNET_TRANSPORT_ps2s (state));
    GNUNET_break (0);
    break;
  }
  return GNUNET_SYSERR;
}
 
 
const char *
GNUNET_TRANSPORT_ps2s (enum GNUNET_TRANSPORT_PeerState state)
{
  switch (state)
  {
  case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
    return "S_NOT_CONNECTED";
 
  case GNUNET_TRANSPORT_PS_INIT_ATS:
    return "S_INIT_ATS";
 
  case GNUNET_TRANSPORT_PS_SYN_SENT:
    return "S_SYN_SENT";
 
  case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
    return "S_SYN_RECV_ATS";
 
  case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
    return "S_SYN_RECV_ACK";
 
  case GNUNET_TRANSPORT_PS_CONNECTED:
    return "S_CONNECTED";
 
  case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
    return "S_RECONNECT_ATS";
 
  case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
    return "S_RECONNECT_SENT";
 
  case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
    return "S_SWITCH_SYN_SENT";
 
  case GNUNET_TRANSPORT_PS_DISCONNECT:
    return "S_DISCONNECT";
 
  case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
    return "S_DISCONNECT_FINISHED";
 
  default:
    GNUNET_break (0);
    return "UNDEFINED";
  }
}
 
 
static void
do_peer_connect (void *cls);
 
 
static void
reconnect_peer_ctx (struct GNUNET_TRANSPORT_PeerMonitoringContext *pal_ctx)
{
  GNUNET_assert (GNUNET_NO == pal_ctx->one_shot);
  GNUNET_MQ_destroy (pal_ctx->mq);
  pal_ctx->mq = NULL;
  pal_ctx->cb (pal_ctx->cb_cls,
               NULL,
               NULL,
               GNUNET_TRANSPORT_PS_NOT_CONNECTED,
               GNUNET_TIME_UNIT_ZERO_ABS);
  pal_ctx->backoff = GNUNET_TIME_STD_BACKOFF (pal_ctx->backoff);
  pal_ctx->reconnect_task = GNUNET_SCHEDULER_add_delayed (pal_ctx->backoff,
                                                          &do_peer_connect,
                                                          pal_ctx);
}
 
 
static void
handle_response_end (void *cls,
                     const struct GNUNET_MessageHeader *msg)
{
  struct GNUNET_TRANSPORT_PeerMonitoringContext *pal_ctx = cls;
 
  if (pal_ctx->one_shot)
  {
    /* iteration finished */
    pal_ctx->cb (pal_ctx->cb_cls,
                 NULL,
                 NULL,
                 GNUNET_TRANSPORT_PS_NOT_CONNECTED,
                 GNUNET_TIME_UNIT_ZERO_ABS);
    GNUNET_TRANSPORT_monitor_peers_cancel (pal_ctx);
    return;
  }
  /* not quite what we expected, reconnect */
  GNUNET_break (0);
  reconnect_peer_ctx (pal_ctx);
}
 
 
static int
check_response (void *cls,
                const struct PeerIterateResponseMessage *pir_msg)
{
  uint16_t size = ntohs (pir_msg->header.size) - sizeof(*pir_msg);
  size_t alen = ntohl (pir_msg->addrlen);
  size_t tlen = ntohl (pir_msg->pluginlen);
  const char *addr;
  const char *transport_name;
 
  if (size != tlen + alen)
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  if ((0 == tlen) && (0 == alen))
    return GNUNET_OK;
  if (0 == tlen)
  {
    GNUNET_break (0);  /* This must not happen: address without plugin */
    return GNUNET_SYSERR;
  }
  addr = (const char *) &pir_msg[1];
  transport_name = &addr[alen];
  if (transport_name[tlen - 1] != '\0')
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }
  return GNUNET_OK;
}
 
 
static void
handle_response (void *cls,
                 const struct PeerIterateResponseMessage *pir_msg)
{
  struct GNUNET_TRANSPORT_PeerMonitoringContext *pal_ctx = cls;
  struct GNUNET_HELLO_Address *address;
  size_t alen = ntohl (pir_msg->addrlen);
  size_t tlen = ntohl (pir_msg->pluginlen);
  const char *addr;
  const char *transport_name;
 
  if ((0 == tlen) &&
      (0 == alen))
  {
    /* No address available */
    pal_ctx->cb (pal_ctx->cb_cls,
                 &pir_msg->peer,
                 NULL,
                 ntohl (pir_msg->state),
                 GNUNET_TIME_absolute_ntoh (pir_msg->state_timeout));
    return;
  }
  addr = (const char *) &pir_msg[1];
  transport_name = &addr[alen];
 
  /* notify client */
  address = GNUNET_HELLO_address_allocate (&pir_msg->peer,
                                           transport_name,
                                           addr,
                                           alen,
                                           ntohl (pir_msg->local_address_info));
  pal_ctx->cb (pal_ctx->cb_cls,
               &pir_msg->peer,
               address,
               ntohl (pir_msg->state),
               GNUNET_TIME_absolute_ntoh (pir_msg->state_timeout));
  GNUNET_HELLO_address_free (address);
}
 
 
static void
mq_error_handler (void *cls,
                  enum GNUNET_MQ_Error error)
{
  struct GNUNET_TRANSPORT_PeerMonitoringContext *pal_ctx = cls;
 
  if (pal_ctx->one_shot)
  {
    /* Disconnect */
    pal_ctx->cb (pal_ctx->cb_cls,
                 NULL,
                 NULL,
                 GNUNET_TRANSPORT_PS_NOT_CONNECTED,
                 GNUNET_TIME_UNIT_ZERO_ABS);
    GNUNET_TRANSPORT_monitor_peers_cancel (pal_ctx);
    return;
  }
  reconnect_peer_ctx (pal_ctx);
}
 
 
static void
do_peer_connect (void *cls)
{
  struct GNUNET_TRANSPORT_PeerMonitoringContext *pal_ctx = cls;
  struct GNUNET_MQ_MessageHandler handlers[] = {
    GNUNET_MQ_hd_var_size (response,
                           GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_RESPONSE,
                           struct PeerIterateResponseMessage,
                           pal_ctx),
    GNUNET_MQ_hd_fixed_size (response_end,
                             GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_RESPONSE_END,
                             struct GNUNET_MessageHeader,
                             pal_ctx),
    GNUNET_MQ_handler_end ()
  };
  struct PeerMonitorMessage *msg;
  struct GNUNET_MQ_Envelope *env;
 
  pal_ctx->reconnect_task = NULL;
  pal_ctx->mq = GNUNET_CLIENT_connect (pal_ctx->cfg,
                                       "transport",
                                       handlers,
                                       &mq_error_handler,
                                       pal_ctx);
  if (NULL == pal_ctx->mq)
    return;
  env = GNUNET_MQ_msg (msg,
                       GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_REQUEST);
  msg->one_shot = htonl (pal_ctx->one_shot);
  msg->peer = pal_ctx->peer;
  GNUNET_MQ_send (pal_ctx->mq,
                  env);
}
 
 
struct GNUNET_TRANSPORT_PeerMonitoringContext *
GNUNET_TRANSPORT_monitor_peers (const struct GNUNET_CONFIGURATION_Handle *cfg,
                                const struct GNUNET_PeerIdentity *peer,
                                int one_shot,
                                GNUNET_TRANSPORT_PeerIterateCallback
                                peer_callback,
                                void *peer_callback_cls)
{
  struct GNUNET_TRANSPORT_PeerMonitoringContext *pal_ctx
    = GNUNET_new (struct GNUNET_TRANSPORT_PeerMonitoringContext);
 
  pal_ctx->cb = peer_callback;
  pal_ctx->cb_cls = peer_callback_cls;
  pal_ctx->cfg = cfg;
  if (NULL != peer)
    pal_ctx->peer = *peer;
  pal_ctx->one_shot = one_shot;
  do_peer_connect (pal_ctx);
  if (NULL == pal_ctx->mq)
  {
    GNUNET_free (pal_ctx);
    return NULL;
  }
  return pal_ctx;
}
 
 
void
GNUNET_TRANSPORT_monitor_peers_cancel (struct
                                       GNUNET_TRANSPORT_PeerMonitoringContext *
                                       pic)
{
  if (NULL != pic->mq)
  {
    GNUNET_MQ_destroy (pic->mq);
    pic->mq = NULL;
  }
  if (NULL != pic->reconnect_task)
  {
    GNUNET_SCHEDULER_cancel (pic->reconnect_task);
    pic->reconnect_task = NULL;
  }
  GNUNET_free (pic);
}
 
 
/* end of transport_api_monitor_peers.c */