gnunet-service-messenger_tunnel.c

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/*
   This file is part of GNUnet.
   Copyright (C) 2020--2024 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 "gnunet-service-messenger_tunnel.h"
 
#include "gnunet-service-messenger_handle.h"
#include "gnunet-service-messenger_message_recv.h"
#include "gnunet-service-messenger_message_store.h"
#include "gnunet-service-messenger_operation_store.h"
#include "gnunet-service-messenger_operation.h"
 
#include "messenger_api_util.h"
 
struct GNUNET_MESSENGER_SrvTunnel*
create_tunnel (struct GNUNET_MESSENGER_SrvRoom *room,
               const struct GNUNET_PeerIdentity *door)
{
  GNUNET_assert ((room) && (door));
 
  struct GNUNET_MESSENGER_SrvTunnel *tunnel = GNUNET_new (struct
                                                          GNUNET_MESSENGER_SrvTunnel);
 
  tunnel->room = room;
  tunnel->channel = NULL;
 
  tunnel->peer = GNUNET_PEER_intern (door);
 
  tunnel->messenger_version = 0;
 
  tunnel->peer_message = NULL;
 
  init_message_state (&(tunnel->state));
 
  return tunnel;
}
 
 
void
destroy_tunnel (struct GNUNET_MESSENGER_SrvTunnel *tunnel)
{
  GNUNET_assert (tunnel);
 
  if (tunnel->channel)
    GNUNET_CADET_channel_destroy (tunnel->channel);
 
  GNUNET_PEER_change_rc (tunnel->peer, -1);
 
  if (tunnel->peer_message)
    GNUNET_free (tunnel->peer_message);
 
  clear_message_state (&(tunnel->state));
 
  GNUNET_free (tunnel);
}
 
 
void
bind_tunnel (struct GNUNET_MESSENGER_SrvTunnel *tunnel,
             struct GNUNET_CADET_Channel *channel)
{
  GNUNET_assert (tunnel);
 
  if (tunnel->channel)
    delayed_disconnect_channel (tunnel->channel);
 
  tunnel->channel = channel;
}
 
 
extern void
callback_room_disconnect (struct GNUNET_MESSENGER_SrvRoom *room,
                          void *cls);
 
void
callback_tunnel_disconnect (void *cls,
                            const struct GNUNET_CADET_Channel *channel)
{
  struct GNUNET_MESSENGER_SrvTunnel *tunnel = cls;
 
  if (tunnel)
  {
    tunnel->channel = NULL;
 
    callback_room_disconnect (tunnel->room, cls);
  }
}
 
 
extern enum GNUNET_GenericReturnValue
callback_verify_room_message (struct GNUNET_MESSENGER_SrvRoom *room,
                              void *cls,
                              struct GNUNET_MESSENGER_Message *message,
                              struct GNUNET_HashCode *hash);
 
enum GNUNET_GenericReturnValue
check_tunnel_message (void *cls,
                      const struct GNUNET_MessageHeader *header)
{
  struct GNUNET_MESSENGER_SrvTunnel *tunnel = cls;
 
  if (! tunnel)
    return GNUNET_SYSERR;
 
  const uint16_t length = ntohs (header->size) - sizeof(*header);
  const char *buffer = (const char*) &header[1];
 
  struct GNUNET_MESSENGER_Message message;
 
  if (length < get_message_kind_size (GNUNET_MESSENGER_KIND_UNKNOWN,
                                      GNUNET_YES))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Tunnel error: Message too short! (%d)\n", length);
    return GNUNET_SYSERR;
  }
 
  uint16_t padding = 0;
 
  if (GNUNET_YES != decode_message (&message, length, buffer, GNUNET_YES,
                                    &padding))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Tunnel error: Decoding failed!\n");
    return GNUNET_SYSERR;
  }
 
  struct GNUNET_HashCode hash;
  hash_message (&message, length - padding, buffer, &hash);
 
  return callback_verify_room_message (tunnel->room, cls, &message, &hash);
}
 
 
extern enum GNUNET_GenericReturnValue
update_room_message (struct GNUNET_MESSENGER_SrvRoom *room,
                     struct GNUNET_MESSENGER_Message *message,
                     const struct GNUNET_HashCode *hash);
 
extern void
callback_room_handle_message (struct GNUNET_MESSENGER_SrvRoom *room,
                              const struct GNUNET_MESSENGER_Message *message,
                              const struct GNUNET_HashCode *hash);
 
static void
update_tunnel_last_message (struct GNUNET_MESSENGER_SrvTunnel *tunnel,
                            const struct GNUNET_HashCode *hash)
{
  struct GNUNET_MESSENGER_OperationStore *operation_store =
    get_srv_room_operation_store (tunnel->room);
 
  enum GNUNET_GenericReturnValue requested;
  requested = (GNUNET_MESSENGER_OP_REQUEST ==
               get_store_operation_type (operation_store, hash)?
               GNUNET_YES : GNUNET_NO);
 
  struct GNUNET_MESSENGER_MessageStore *message_store =
    get_srv_room_message_store (tunnel->room);
 
  const struct GNUNET_MESSENGER_Message *message = get_store_message (
    message_store, hash);
 
  if (message)
    update_message_state (&(tunnel->state), requested, message, hash);
}
 
 
void
handle_tunnel_message (void *cls, const struct GNUNET_MessageHeader *header)
{
  struct GNUNET_MESSENGER_SrvTunnel *tunnel = cls;
 
  if (! tunnel)
    return;
 
  const uint16_t length = ntohs (header->size) - sizeof(*header);
  const char *buffer = (const char*) &header[1];
 
  struct GNUNET_MESSENGER_Message message;
  struct GNUNET_HashCode hash;
 
  uint16_t padding = 0;
 
  decode_message (&message, length, buffer, GNUNET_YES, &padding);
  hash_message (&message, length - padding, buffer, &hash);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Got message of kind: %s!\n",
              GNUNET_MESSENGER_name_of_kind (message.header.kind));
 
  enum GNUNET_GenericReturnValue new_message;
  new_message = update_room_message (tunnel->room,
                                     copy_message (&message),
                                     &hash);
 
  if (GNUNET_YES != new_message)
    goto receive_done;
 
  update_tunnel_last_message (tunnel, &hash);
 
  enum GNUNET_GenericReturnValue forward_message = GNUNET_YES;
 
  switch (message.header.kind)
  {
  case GNUNET_MESSENGER_KIND_INFO:
    forward_message = recv_message_info (tunnel->room, tunnel, &message, &hash);
    break;
  case GNUNET_MESSENGER_KIND_PEER:
    forward_message = recv_message_peer (tunnel->room, tunnel, &message, &hash);
    break;
  case GNUNET_MESSENGER_KIND_MISS:
    forward_message = recv_message_miss (tunnel->room, tunnel, &message, &hash);
    break;
  case GNUNET_MESSENGER_KIND_REQUEST:
    forward_message = recv_message_request (tunnel->room, tunnel, &message,
                                            &hash);
    break;
  default:
    break;
  }
 
  if (GNUNET_YES == forward_message)
  {
    forward_srv_room_message (tunnel->room, tunnel, &message, &hash);
    callback_room_handle_message (tunnel->room, &message, &hash);
  }
 
receive_done:
  cleanup_message (&message);
 
  GNUNET_CADET_receive_done (tunnel->channel);
}
 
 
enum GNUNET_GenericReturnValue
connect_tunnel (struct GNUNET_MESSENGER_SrvTunnel *tunnel)
{
  GNUNET_assert (tunnel);
 
  if (tunnel->channel)
    return GNUNET_NO;
 
  const struct GNUNET_PeerIdentity *door = GNUNET_PEER_resolve2 (tunnel->peer);
 
  struct GNUNET_CADET_Handle *cadet = get_srv_room_cadet (tunnel->room);
  const struct GNUNET_HashCode *key = get_srv_room_key (tunnel->room);
 
  struct GNUNET_MQ_MessageHandler handlers[] = { GNUNET_MQ_hd_var_size (
                                                   tunnel_message,
                                                   GNUNET_MESSAGE_TYPE_CADET_CLI,
                                                   struct
                                                   GNUNET_MessageHeader, NULL),
                                                 GNUNET_MQ_handler_end () };
 
  struct GNUNET_HashCode port;
  convert_messenger_key_to_port (key, &port);
  tunnel->channel = GNUNET_CADET_channel_create (cadet, tunnel, door, &port,
                                                 NULL,
                                                 callback_tunnel_disconnect,
                                                 handlers);
 
  return GNUNET_YES;
}
 
 
void
disconnect_tunnel (struct GNUNET_MESSENGER_SrvTunnel *tunnel)
{
  GNUNET_assert (tunnel);
 
  if (tunnel->channel)
  {
    delayed_disconnect_channel (tunnel->channel);
 
    tunnel->channel = NULL;
  }
}
 
 
enum GNUNET_GenericReturnValue
is_tunnel_connected (const struct GNUNET_MESSENGER_SrvTunnel *tunnel)
{
  GNUNET_assert (tunnel);
 
  return (tunnel->channel ? GNUNET_YES : GNUNET_NO);
}
 
 
struct GNUNET_MESSENGER_MessageSent
{
  struct GNUNET_MESSENGER_SrvTunnel *tunnel;
  struct GNUNET_HashCode hash;
};
 
static void
callback_tunnel_sent (void *cls)
{
  struct GNUNET_MESSENGER_MessageSent *sent = cls;
 
  if (sent->tunnel)
    update_tunnel_last_message (sent->tunnel, &(sent->hash));
 
  GNUNET_free (sent);
}
 
 
void
send_tunnel_envelope (struct GNUNET_MESSENGER_SrvTunnel *tunnel,
                      struct GNUNET_MQ_Envelope *env,
                      const struct GNUNET_HashCode *hash)
{
  GNUNET_assert ((tunnel) && (env) && (hash));
 
  struct GNUNET_MQ_Handle *mq = GNUNET_CADET_get_mq (tunnel->channel);
 
  struct GNUNET_MESSENGER_MessageSent *sent = GNUNET_new (struct
                                                          GNUNET_MESSENGER_MessageSent);
 
  GNUNET_memcpy (&(sent->hash), hash, sizeof(struct GNUNET_HashCode));
 
  sent->tunnel = tunnel;
 
  GNUNET_MQ_notify_sent (env, callback_tunnel_sent, sent);
  GNUNET_MQ_send (mq, env);
}
 
 
enum GNUNET_GenericReturnValue
send_tunnel_message (struct GNUNET_MESSENGER_SrvTunnel *tunnel,
                     void *handle,
                     struct GNUNET_MESSENGER_Message *message)
{
  GNUNET_assert ((tunnel) && (handle));
 
  if (! message)
    return GNUNET_NO;
 
  struct GNUNET_HashCode hash;
  struct GNUNET_MQ_Envelope *env = pack_srv_room_message (
    tunnel->room, (struct GNUNET_MESSENGER_SrvHandle*) handle,
    message, &hash, GNUNET_MESSENGER_PACK_MODE_ENVELOPE
    );
 
  destroy_message (message);
 
  if (! env)
    return GNUNET_NO;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending tunnel message: %s\n",
              GNUNET_h2s (&hash));
 
  send_tunnel_envelope (tunnel, env, &hash);
  return GNUNET_YES;
}
 
 
void
forward_tunnel_message (struct GNUNET_MESSENGER_SrvTunnel *tunnel,
                        const struct GNUNET_MESSENGER_Message *message,
                        const struct GNUNET_HashCode *hash)
{
  GNUNET_assert ((tunnel) && (message) && (hash));
 
  struct GNUNET_MESSENGER_Message *copy = copy_message (message);
  struct GNUNET_MQ_Envelope *env = pack_message (copy, NULL, NULL,
                                                 GNUNET_MESSENGER_PACK_MODE_ENVELOPE,
                                                 NULL);
 
  destroy_message (copy);
 
  if (! env)
    return;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Forwarding tunnel message: %s\n",
              GNUNET_h2s (hash));
 
  send_tunnel_envelope (tunnel, env, hash);
}
 
 
const struct GNUNET_HashCode*
get_tunnel_peer_message (const struct GNUNET_MESSENGER_SrvTunnel *tunnel)
{
  GNUNET_assert (tunnel);
 
  return tunnel->peer_message;
}
 
 
void
get_tunnel_peer_identity (const struct GNUNET_MESSENGER_SrvTunnel *tunnel,
                          struct GNUNET_PeerIdentity *peer)
{
  GNUNET_assert (tunnel);
 
  GNUNET_PEER_resolve (tunnel->peer, peer);
}
 
 
uint32_t
get_tunnel_messenger_version (const struct GNUNET_MESSENGER_SrvTunnel *tunnel)
{
  GNUNET_assert (tunnel);
 
  return tunnel->messenger_version;
}
 
 
enum GNUNET_GenericReturnValue
update_tunnel_messenger_version (struct GNUNET_MESSENGER_SrvTunnel *tunnel,
                                 uint32_t version)
{
  GNUNET_assert (tunnel);
 
  if (version != GNUNET_MESSENGER_VERSION)
    return GNUNET_SYSERR;
 
  if (version > tunnel->messenger_version)
    tunnel->messenger_version = version;
 
  return GNUNET_OK;
}