uncrustify as demanded.

[oweals/gnunet.git] / src / transport / gnunet-service-transport.c

/*
   This file is part of GNUnet.
   Copyright (C) 2010-2016 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
 */
/**
 * @file transport/gnunet-service-transport.c
 * @brief main for gnunet-service-transport
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_hello_lib.h"
#include "gnunet_statistics_service.h"
#include "gnunet_transport_service.h"
#include "gnunet_peerinfo_service.h"
#include "gnunet_ats_service.h"
#include "gnunet-service-transport.h"
#include "gnunet-service-transport_ats.h"
#include "gnunet-service-transport_hello.h"
#include "gnunet-service-transport_neighbours.h"
#include "gnunet-service-transport_plugins.h"
#include "gnunet-service-transport_validation.h"
#include "gnunet-service-transport_manipulation.h"
#include "transport.h"

/**
 * Size of the blacklist hash map.
 */
#define TRANSPORT_BLACKLIST_HT_SIZE 64

/**
 * How many messages can we have pending for a given client process
 * before we start to drop incoming messages?  We typically should
 * have only one client and so this would be the primary buffer for
 * messages, so the number should be chosen rather generously.
 *
 * The expectation here is that most of the time the queue is large
 * enough so that a drop is virtually never required.  Note that
 * this value must be about as large as 'TOTAL_MSGS' in the
 * 'test_transport_api_reliability.c', otherwise that testcase may
 * fail.
 */
#define MAX_PENDING (128 * 1024)


/**
 * Information we need for an asynchronous session kill.
 */
struct GNUNET_ATS_SessionKiller {
  /**
   * Kept in a DLL.
   */
  struct GNUNET_ATS_SessionKiller *next;

  /**
   * Kept in a DLL.
   */
  struct GNUNET_ATS_SessionKiller *prev;

  /**
   * Session to kill.
   */
  struct GNUNET_ATS_Session *session;

  /**
   * Plugin for the session.
   */
  struct GNUNET_TRANSPORT_PluginFunctions *plugin;

  /**
   * The kill task.
   */
  struct GNUNET_SCHEDULER_Task *task;
};


/**
 * What type of client is the `struct TransportClient` about?
 */
enum ClientType {
  /**
   * We do not know yet (client is fresh).
   */
  CT_NONE = 0,

  /**
   * Is the CORE service, we need to forward traffic to it.
   */
  CT_CORE = 1,

  /**
   * It is a monitor, forward monitor data.
   */
  CT_MONITOR = 2,

  /**
   * It is a blacklist, query about allowed connections.
   */
  CT_BLACKLIST = 3,

  /**
   * CORE client without any handlers.
   */
  CT_CORE_NO_HANDLERS = 4
};


/**
 * Context we use when performing a blacklist check.
 */
struct GST_BlacklistCheck;

/**
 * Client connected to the transport service.
 */
struct TransportClient {
  /**
   * This is a doubly-linked list.
   */
  struct TransportClient *next;

  /**
   * This is a doubly-linked list.
   */
  struct TransportClient *prev;

  /**
   * Handle to the client.
   */
  struct GNUNET_SERVICE_Client *client;

  /**
   * Message queue to the client.
   */
  struct GNUNET_MQ_Handle *mq;

  /**
   * What type of client is this?
   */
  enum ClientType type;

  union {
    /**
     * Peer identity to monitor the addresses of.
     * Zero to monitor all neighbours.  Valid if
     * @e type is CT_MONITOR.
     */
    struct GNUNET_PeerIdentity monitor_peer;

    /**
     * Additional details if @e type is CT_BLACKLIST.
     */
    struct {
      /**
       * Blacklist check that we're currently performing (or NULL
       * if we're performing one that has been cancelled).
       */
      struct GST_BlacklistCheck *bc;

      /**
       * Set to #GNUNET_YES if we're currently waiting for a reply.
       */
      int waiting_for_reply;

      /**
       * #GNUNET_YES if we have to call receive_done for this client
       */
      int call_receive_done;
    } blacklist;
  } details;
};


/**
 * Context we use when performing a blacklist check.
 */
struct GST_BlacklistCheck {
  /**
   * This is a linked list.
   */
  struct GST_BlacklistCheck *next;

  /**
   * This is a linked list.
   */
  struct GST_BlacklistCheck *prev;

  /**
   * Peer being checked.
   */
  struct GNUNET_PeerIdentity peer;

  /**
   * Continuation to call with the result.
   */
  GST_BlacklistTestContinuation cont;

  /**
   * Closure for @e cont.
   */
  void *cont_cls;

  /**
   * Address for #GST_blacklist_abort_matching(), can be NULL.
   */
  struct GNUNET_HELLO_Address *address;

  /**
   * Session for #GST_blacklist_abort_matching(), can be NULL.
   */
  struct GNUNET_ATS_Session *session;

  /**
   * Our current position in the blacklisters list.
   */
  struct TransportClient *bl_pos;

  /**
   * Current task performing the check.
   */
  struct GNUNET_SCHEDULER_Task *task;
};


/**
 * Context for address to string operations
 */
struct AddressToStringContext {
  /**
   * This is a doubly-linked list.
   */
  struct AddressToStringContext *next;

  /**
   * This is a doubly-linked list.
   */
  struct AddressToStringContext *prev;

  /**
   * Client that made the request.
   */
  struct TransportClient *tc;
};


/**
 * Closure for #handle_send_transmit_continuation()
 */
struct SendTransmitContinuationContext {
  /**
   * Client that made the request.
   */
  struct TransportClient *tc;

  /**
   * Peer that was the target.
   */
  struct GNUNET_PeerIdentity target;

  /**
   * At what time did we receive the message?
   */
  struct GNUNET_TIME_Absolute send_time;

  /**
   * Unique ID, for logging.
   */
  unsigned long long uuid;

  /**
   * Set to #GNUNET_YES if the connection for @e target goes
   * down and we thus must no longer send the
   * #GNUNET_MESSAGE_TYPE_TRANSPORT_SEND_OK message.
   */
  int down;
};


/**
 * Head of linked list of all clients to this service.
 */
static struct TransportClient *clients_head;

/**
 * Tail of linked list of all clients to this service.
 */
static struct TransportClient *clients_tail;

/**
 * Map of peer identities to active send transmit continuation
 * contexts. Used to flag contexts as 'dead' when a connection goes
 * down. Values are of type `struct SendTransmitContinuationContext
 * *`.
 */
static struct GNUNET_CONTAINER_MultiPeerMap *active_stccs;

/**
 * Head of linked list of all pending address iterations
 */
static struct AddressToStringContext *a2s_head;

/**
 * Tail of linked list of all pending address iterations
 */
static struct AddressToStringContext *a2s_tail;

/**
 * Head of DLL of active blacklisting queries.
 */
static struct GST_BlacklistCheck *bc_head;

/**
 * Tail of DLL of active blacklisting queries.
 */
static struct GST_BlacklistCheck *bc_tail;

/**
 * Hashmap of blacklisted peers.  Values are of type 'char *' (transport names),
 * can be NULL if we have no static blacklist.
 */
static struct GNUNET_CONTAINER_MultiPeerMap *blacklist;

/**
 * Notification context, to send updates on changes to active plugin
 * connections.
 */
static struct GNUNET_NotificationContext *plugin_nc;

/**
 * Plugin monitoring client we are currently syncing, NULL if all
 * monitoring clients are in sync.
 */
static struct TransportClient *sync_client;

/**
 * Peer identity that is all zeros, used as a way to indicate
 * "all peers".  Used for comparissons.
 */
static struct GNUNET_PeerIdentity all_zeros;

/**
 * Statistics handle.
 */
struct GNUNET_STATISTICS_Handle *GST_stats;

/**
 * Configuration handle.
 */
const struct GNUNET_CONFIGURATION_Handle *GST_cfg;

/**
 * Configuration handle.
 */
struct GNUNET_PeerIdentity GST_my_identity;

/**
 * Handle to peerinfo service.
 */
struct GNUNET_PEERINFO_Handle *GST_peerinfo;

/**
 * Our private key.
 */
struct GNUNET_CRYPTO_EddsaPrivateKey *GST_my_private_key;

/**
 * ATS scheduling handle.
 */
struct GNUNET_ATS_SchedulingHandle *GST_ats;

/**
 * ATS connectivity handle.
 */
struct GNUNET_ATS_ConnectivityHandle *GST_ats_connect;

/**
 * Hello address expiration
 */
struct GNUNET_TIME_Relative hello_expiration;

/**
 * Head of DLL of asynchronous tasks to kill sessions.
 */
static struct GNUNET_ATS_SessionKiller *sk_head;

/**
 * Tail of DLL of asynchronous tasks to kill sessions.
 */
static struct GNUNET_ATS_SessionKiller *sk_tail;

/**
 * Interface scanner determines our LAN address range(s).
 */
struct GNUNET_NT_InterfaceScanner *GST_is;

/**
 * Queue the given message for transmission to the given client
 *
 * @param tc target of the message
 * @param msg message to transmit
 * @param may_drop #GNUNET_YES if the message can be dropped
 */
static void
unicast(struct TransportClient *tc,
        const struct GNUNET_MessageHeader *msg,
        int may_drop)
{
  struct GNUNET_MQ_Envelope *env;

  if ((GNUNET_MQ_get_length(tc->mq) >= MAX_PENDING) &&
      (GNUNET_YES == may_drop))
    {
      GNUNET_log(
        GNUNET_ERROR_TYPE_DEBUG,
        "Dropping message of type %u and size %u, have %u/%u messages pending\n",
        ntohs(msg->type),
        ntohs(msg->size),
        GNUNET_MQ_get_length(tc->mq),
        MAX_PENDING);
      GNUNET_STATISTICS_update(GST_stats,
                               gettext_noop(
                                 "# messages dropped due to slow client"),
                               1,
                               GNUNET_NO);
      return;
    }
  env = GNUNET_MQ_msg_copy(msg);
  GNUNET_MQ_send(tc->mq, env);
}


/**
 * Called whenever a client connects.  Allocates our
 * data structures associated with that client.
 *
 * @param cls closure, NULL
 * @param client identification of the client
 * @param mq message queue for the client
 * @return our `struct TransportClient`
 */
static void *
client_connect_cb(void *cls,
                  struct GNUNET_SERVICE_Client *client,
                  struct GNUNET_MQ_Handle *mq)
{
  struct TransportClient *tc;

  tc = GNUNET_new(struct TransportClient);
  tc->client = client;
  tc->mq = mq;
  GNUNET_CONTAINER_DLL_insert(clients_head, clients_tail, tc);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Client %p connected\n", tc);
  return tc;
}


/**
 * Perform next action in the blacklist check.
 *
 * @param cls the `struct BlacklistCheck*`
 */
static void
do_blacklist_check(void *cls);


/**
 * Mark the peer as down so we don't call the continuation
 * context in the future.
 *
 * @param cls a `struct TransportClient`
 * @param peer a peer we are sending to
 * @param value a `struct SendTransmitContinuationContext` to mark
 * @return #GNUNET_OK (continue to iterate)
 */
static int
mark_match_down(void *cls, const struct GNUNET_PeerIdentity *peer, void *value)
{
  struct TransportClient *tc = cls;
  struct SendTransmitContinuationContext *stcc = value;

  if (tc == stcc->tc)
    {
      stcc->down = GNUNET_YES;
      stcc->tc = NULL;
    }
  return GNUNET_OK;
}


/**
 * Called whenever a client is disconnected.  Frees our
 * resources associated with that client.
 *
 * @param cls closure, NULL
 * @param client identification of the client
 * @param app_ctx our `struct TransportClient`
 */
static void
client_disconnect_cb(void *cls,
                     struct GNUNET_SERVICE_Client *client,
                     void *app_ctx)
{
  struct TransportClient *tc = app_ctx;
  struct GST_BlacklistCheck *bc;

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Client %p disconnected, cleaning up.\n",
             tc);
  GNUNET_CONTAINER_multipeermap_iterate(active_stccs, &mark_match_down, tc);
  for (struct AddressToStringContext *cur = a2s_head; NULL != cur;
       cur = cur->next)
    {
      if (cur->tc == tc)
        cur->tc = NULL;
    }
  GNUNET_CONTAINER_DLL_remove(clients_head, clients_tail, tc);
  switch (tc->type)
    {
    case CT_NONE:
      break;

    case CT_CORE:
      break;

    case CT_MONITOR:
      break;

    case CT_BLACKLIST:
      for (bc = bc_head; NULL != bc; bc = bc->next)
        {
          if (bc->bl_pos != tc)
            continue;
          bc->bl_pos = tc->next;
          if (NULL == bc->task)
            bc->task = GNUNET_SCHEDULER_add_now(&do_blacklist_check, bc);
        }
      break;

    case CT_CORE_NO_HANDLERS:
      break;
    }
  GNUNET_free(tc);
}


/**
 * Function called for each of our connected neighbours.  Notify the
 * client about the existing neighbour.
 *
 * @param cls the `struct TransportClient *` to notify
 * @param peer identity of the neighbour
 * @param address the address
 * @param state the current state of the peer
 * @param state_timeout the time out for the state
 * @param bandwidth_in inbound bandwidth in NBO
 * @param bandwidth_out outbound bandwidth in NBO
 */
static void
notify_client_about_neighbour(void *cls,
                              const struct GNUNET_PeerIdentity *peer,
                              const struct GNUNET_HELLO_Address *address,
                              enum GNUNET_TRANSPORT_PeerState state,
                              struct GNUNET_TIME_Absolute state_timeout,
                              struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
                              struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
{
  struct TransportClient *tc = cls;
  struct ConnectInfoMessage cim;

  if (GNUNET_NO == GST_neighbours_test_connected(peer))
    return;
  cim.header.size = htons(sizeof(struct ConnectInfoMessage));
  cim.header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
  cim.id = *peer;
  cim.quota_out = bandwidth_out;
  unicast(tc, &cim.header, GNUNET_NO);
}


/**
 * Initialize a normal client.  We got a start message from this
 * client, add it to the list of clients for broadcasting of inbound
 * messages.
 *
 * @param cls the client
 * @param start the start message that was sent
 */
static void
handle_client_start(void *cls, const struct StartMessage *start)
{
  struct TransportClient *tc = cls;
  const struct GNUNET_MessageHeader *hello;
  uint32_t options;

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Client %p sent START\n", tc);
  options = ntohl(start->options);
  if ((0 != (1 & options)) &&
      (0 != memcmp(&start->self,
                   &GST_my_identity,
                   sizeof(struct GNUNET_PeerIdentity))))
    {
      /* client thinks this is a different peer, reject */
      GNUNET_break(0);
      GNUNET_SERVICE_client_drop(tc->client);
      return;
    }
  if (CT_NONE != tc->type)
    {
      GNUNET_break(0);
      GNUNET_SERVICE_client_drop(tc->client);
      return;
    }
  if (0 != (2 & options))
    tc->type = CT_CORE;
  else
    tc->type = CT_CORE_NO_HANDLERS;
  hello = GST_hello_get();
  if (NULL != hello)
    unicast(tc, hello, GNUNET_NO);
  GST_neighbours_iterate(&notify_client_about_neighbour, tc);
  GNUNET_SERVICE_client_continue(tc->client);
}


/**
 * Client sent us a HELLO.  Check the request.
 *
 * @param cls the client
 * @param message the HELLO message
 */
static int
check_client_hello(void *cls, const struct GNUNET_MessageHeader *message)
{
  return GNUNET_OK; /* FIXME: check here? */
}


/**
 * Client sent us a HELLO.  Process the request.
 *
 * @param cls the client
 * @param message the HELLO message
 */
static void
handle_client_hello(void *cls, const struct GNUNET_MessageHeader *message)
{
  struct TransportClient *tc = cls;

  GNUNET_log(GNUNET_ERROR_TYPE_INFO, "Received HELLO message\n");
  GST_validation_handle_hello(message);
  GNUNET_SERVICE_client_continue(tc->client);
}


/**
 * Function called after the transmission is done.  Notify the client that it is
 * OK to send the next message.
 *
 * @param cls closure
 * @param success #GNUNET_OK on success, #GNUNET_NO on failure, #GNUNET_SYSERR if we're not connected
 * @param bytes_payload bytes payload sent
 * @param bytes_on_wire bytes sent on wire
 */
static void
handle_send_transmit_continuation(void *cls,
                                  int success,
                                  size_t bytes_payload,
                                  size_t bytes_on_wire)
{
  struct SendTransmitContinuationContext *stcc = cls;
  struct SendOkMessage send_ok_msg;
  struct GNUNET_TIME_Relative delay;
  const struct GNUNET_HELLO_Address *addr;

  delay = GNUNET_TIME_absolute_get_duration(stcc->send_time);
  addr = GST_neighbour_get_current_address(&stcc->target);
  if (delay.rel_value_us > GNUNET_CONSTANTS_LATENCY_WARN.rel_value_us)
    GNUNET_log(GNUNET_ERROR_TYPE_WARNING,
               "It took us %s to send %u/%u bytes to %s (%d, %s)\n",
               GNUNET_STRINGS_relative_time_to_string(delay, GNUNET_YES),
               (unsigned int)bytes_payload,
               (unsigned int)bytes_on_wire,
               GNUNET_i2s(&stcc->target),
               success,
               (NULL != addr) ? addr->transport_name : "%");
  else
    GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
               "It took us %s to send %u/%u bytes to %s (%d, %s)\n",
               GNUNET_STRINGS_relative_time_to_string(delay, GNUNET_YES),
               (unsigned int)bytes_payload,
               (unsigned int)bytes_on_wire,
               GNUNET_i2s(&stcc->target),
               success,
               (NULL != addr) ? addr->transport_name : "%");

  if (GNUNET_NO == stcc->down)
    {
      /* Only send confirmation if we are still connected */
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "Sending SEND_OK for transmission request %llu\n",
                 stcc->uuid);
      send_ok_msg.header.size = htons(sizeof(send_ok_msg));
      send_ok_msg.header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_SEND_OK);
      send_ok_msg.bytes_msg = htonl(bytes_payload);
      send_ok_msg.bytes_physical = htonl(bytes_on_wire);
      send_ok_msg.success = htonl(success);
      send_ok_msg.peer = stcc->target;
      unicast(stcc->tc, &send_ok_msg.header, GNUNET_NO);
    }
  GNUNET_assert(
    GNUNET_OK ==
    GNUNET_CONTAINER_multipeermap_remove(active_stccs, &stcc->target, stcc));
  GNUNET_free(stcc);
}


/**
 * Client asked for transmission to a peer.  Process the request.
 *
 * @param cls the client
 * @param obm the send message that was sent
 */
static int
check_client_send(void *cls, const struct OutboundMessage *obm)
{
  uint16_t size;
  const struct GNUNET_MessageHeader *obmm;

  size = ntohs(obm->header.size) - sizeof(struct OutboundMessage);
  if (size < sizeof(struct GNUNET_MessageHeader))
    {
      GNUNET_break(0);
      return GNUNET_SYSERR;
    }
  obmm = (const struct GNUNET_MessageHeader *)&obm[1];
  if (size != ntohs(obmm->size))
    {
      GNUNET_break(0);
      return GNUNET_SYSERR;
    }
  return GNUNET_OK;
}


/**
 * Client asked for transmission to a peer.  Process the request.
 *
 * @param cls the client
 * @param obm the send message that was sent
 */
static void
handle_client_send(void *cls, const struct OutboundMessage *obm)
{
  static unsigned long long uuid_gen;
  struct TransportClient *tc = cls;
  const struct GNUNET_MessageHeader *obmm;
  struct SendTransmitContinuationContext *stcc;

  obmm = (const struct GNUNET_MessageHeader *)&obm[1];
  if (GNUNET_NO == GST_neighbours_test_connected(&obm->peer))
    {
      /* not connected, not allowed to send; can happen due to asynchronous operations */
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "Could not send message to peer `%s': not connected\n",
                 GNUNET_i2s(&obm->peer));
      GNUNET_STATISTICS_update(
        GST_stats,
        gettext_noop("# bytes payload dropped (other peer was not connected)"),
        ntohs(obmm->size),
        GNUNET_NO);
      GNUNET_SERVICE_client_continue(tc->client);
      return;
    }
  GNUNET_log(
    GNUNET_ERROR_TYPE_DEBUG,
    "Received SEND request %llu for `%s' and first message of type %u and total size %u\n",
    uuid_gen,
    GNUNET_i2s(&obm->peer),
    ntohs(obmm->type),
    ntohs(obmm->size));
  GNUNET_SERVICE_client_continue(tc->client);

  stcc = GNUNET_new(struct SendTransmitContinuationContext);
  stcc->target = obm->peer;
  stcc->tc = tc;
  stcc->send_time = GNUNET_TIME_absolute_get();
  stcc->uuid = uuid_gen++;
  (void)GNUNET_CONTAINER_multipeermap_put(
    active_stccs,
    &stcc->target,
    stcc,
    GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
  GST_manipulation_send(&obm->peer,
                        obmm,
                        ntohs(obmm->size),
                        GNUNET_TIME_relative_ntoh(obm->timeout),
                        &handle_send_transmit_continuation,
                        stcc);
}


/**
 * Take the given address and append it to the set of results sent back to
 * the client.  This function may be called serveral times for a single
 * conversion.   The last invocation will be with a @a address of
 * NULL and a @a res of #GNUNET_OK.  Thus, to indicate conversion
 * errors, the callback might be called first with @a address NULL and
 * @a res being #GNUNET_SYSERR.  In that case, there will still be a
 * subsequent call later with @a address NULL and @a res #GNUNET_OK.
 *
 * @param cls the `struct AddressToStringContext`
 * @param buf text to transmit (contains the human-readable address, or NULL)
 * @param res #GNUNET_OK if conversion was successful, #GNUNET_SYSERR on error,
 *            never #GNUNET_NO
 */
static void
transmit_address_to_client(void *cls, const char *buf, int res)
{
  struct AddressToStringContext *actx = cls;
  struct GNUNET_MQ_Envelope *env;
  struct AddressToStringResultMessage *atsm;
  size_t slen;

  GNUNET_assert((GNUNET_OK == res) || (GNUNET_SYSERR == res));
  if (NULL == actx->tc)
    return;
  if (NULL == buf)
    {
      env = GNUNET_MQ_msg(atsm,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
      if (GNUNET_OK == res)
        {
          /* this was the last call, transmit */
          atsm->res = htonl(GNUNET_OK);
          atsm->addr_len = htonl(0);
          GNUNET_MQ_send(actx->tc->mq, env);
          GNUNET_CONTAINER_DLL_remove(a2s_head, a2s_tail, actx);
          GNUNET_free(actx);
          return;
        }
      if (GNUNET_SYSERR == res)
        {
          /* address conversion failed, but there will be more callbacks */
          atsm->res = htonl(GNUNET_SYSERR);
          atsm->addr_len = htonl(0);
          GNUNET_MQ_send(actx->tc->mq, env);
          return;
        }
    }
  GNUNET_assert(GNUNET_OK == res);
  /* succesful conversion, append*/
  slen = strlen(buf) + 1;
  env =
    GNUNET_MQ_msg_extra(atsm,
                        slen,
                        GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
  atsm->res = htonl(GNUNET_YES);
  atsm->addr_len = htonl(slen);
  GNUNET_memcpy(&atsm[1], buf, slen);
  GNUNET_MQ_send(actx->tc->mq, env);
}


/**
 * Client asked to resolve an address.  Check the request.
 *
 * @param cls the client
 * @param alum the resolution request
 * @return #GNUNET_OK if @a alum is well-formed
 */
static int
check_client_address_to_string(void *cls,
                               const struct AddressLookupMessage *alum)
{
  const char *plugin_name;
  const char *address;
  uint32_t address_len;
  uint16_t size;

  size = ntohs(alum->header.size);
  address_len = ntohs(alum->addrlen);
  if (size <= sizeof(struct AddressLookupMessage) + address_len)
    {
      GNUNET_break(0);
      return GNUNET_SYSERR;
    }
  address = (const char *)&alum[1];
  plugin_name = (const char *)&address[address_len];
  if ('\0' != plugin_name[size - sizeof(struct AddressLookupMessage) -
                          address_len - 1])
    {
      GNUNET_break(0);
      return GNUNET_SYSERR;
    }
  return GNUNET_OK;
}


/**
 * Client asked to resolve an address.  Process the request.
 *
 * @param cls the client
 * @param alum the resolution request
 */
static void
handle_client_address_to_string(void *cls,
                                const struct AddressLookupMessage *alum)
{
  struct TransportClient *tc = cls;
  struct GNUNET_TRANSPORT_PluginFunctions *papi;
  const char *plugin_name;
  const char *address;
  uint32_t address_len;
  struct AddressToStringContext *actx;
  struct GNUNET_MQ_Envelope *env;
  struct AddressToStringResultMessage *atsm;
  struct GNUNET_TIME_Relative rtimeout;
  int32_t numeric;

  address_len = ntohs(alum->addrlen);
  address = (const char *)&alum[1];
  plugin_name = (const char *)&address[address_len];
  rtimeout = GNUNET_TIME_relative_ntoh(alum->timeout);
  numeric = ntohs(alum->numeric_only);
  papi = GST_plugins_printer_find(plugin_name);
  if (NULL == papi)
    {
      GNUNET_log(GNUNET_ERROR_TYPE_WARNING,
                 "Failed to find plugin `%s'\n",
                 plugin_name);
      env = GNUNET_MQ_msg(atsm,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
      atsm->res = htonl(GNUNET_SYSERR);
      atsm->addr_len = htonl(0);
      GNUNET_MQ_send(tc->mq, env);
      env = GNUNET_MQ_msg(atsm,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
      atsm->res = htonl(GNUNET_OK);
      atsm->addr_len = htonl(0);
      GNUNET_MQ_send(tc->mq, env);
      return;
    }
  actx = GNUNET_new(struct AddressToStringContext);
  actx->tc = tc;
  GNUNET_CONTAINER_DLL_insert(a2s_head, a2s_tail, actx);
  GNUNET_SERVICE_client_disable_continue_warning(tc->client);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Pretty-printing address of %u bytes using plugin `%s'\n",
             address_len,
             plugin_name);
  papi->address_pretty_printer(papi->cls,
                               plugin_name,
                               address,
                               address_len,
                               numeric,
                               rtimeout,
                               &transmit_address_to_client,
                               actx);
}


/**
 * Compose #PeerIterateResponseMessage using the given peer and address.
 *
 * @param peer identity of the peer
 * @param address the address, NULL on disconnect
 * @return composed message
 */
static struct PeerIterateResponseMessage *
compose_address_iterate_response_message(
  const struct GNUNET_PeerIdentity *peer,
  const struct GNUNET_HELLO_Address *address)
{
  struct PeerIterateResponseMessage *msg;
  size_t size;
  size_t tlen;
  size_t alen;
  char *addr;

  GNUNET_assert(NULL != peer);
  if (NULL != address)
    {
      tlen = strlen(address->transport_name) + 1;
      alen = address->address_length;
    }
  else
    {
      tlen = 0;
      alen = 0;
    }
  size = (sizeof(struct PeerIterateResponseMessage) + alen + tlen);
  msg = GNUNET_malloc(size);
  msg->header.size = htons(size);
  msg->header.type =
    htons(GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_RESPONSE);
  msg->reserved = htonl(0);
  msg->peer = *peer;
  msg->addrlen = htonl(alen);
  msg->pluginlen = htonl(tlen);

  if (NULL != address)
    {
      msg->local_address_info = htonl((uint32_t)address->local_info);
      addr = (char *)&msg[1];
      GNUNET_memcpy(addr, address->address, alen);
      GNUNET_memcpy(&addr[alen], address->transport_name, tlen);
    }
  return msg;
}


/**
 * Context for #send_validation_information() and
 * #send_peer_information().
 */
struct IterationContext {
  /**
   * Context to use for the transmission.
   */
  struct TransportClient *tc;

  /**
   * Which peers do we care about?
   */
  struct GNUNET_PeerIdentity id;

  /**
   * #GNUNET_YES if @e id should be ignored because we want all peers.
   */
  int all;
};


/**
 * Output information of neighbours to the given client.
 *
 * @param cls the `struct PeerIterationContext *`
 * @param peer identity of the neighbour
 * @param address the address
 * @param state current state this peer is in
 * @param state_timeout timeout for the current state of the peer
 * @param bandwidth_in inbound quota in NBO
 * @param bandwidth_out outbound quota in NBO
 */
static void
send_peer_information(void *cls,
                      const struct GNUNET_PeerIdentity *peer,
                      const struct GNUNET_HELLO_Address *address,
                      enum GNUNET_TRANSPORT_PeerState state,
                      struct GNUNET_TIME_Absolute state_timeout,
                      struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
                      struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
{
  struct IterationContext *pc = cls;
  struct GNUNET_MQ_Envelope *env;
  struct PeerIterateResponseMessage *msg;

  if ((GNUNET_YES != pc->all) && (0 != memcmp(peer, &pc->id, sizeof(pc->id))))
    return;
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Sending information about `%s' using address `%s' in state `%s'\n",
             GNUNET_i2s(peer),
             (NULL != address) ? GST_plugins_a2s(address) : "<none>",
             GNUNET_TRANSPORT_ps2s(state));
  msg = compose_address_iterate_response_message(peer, address);
  msg->state = htonl(state);
  msg->state_timeout = GNUNET_TIME_absolute_hton(state_timeout);
  env = GNUNET_MQ_msg_copy(&msg->header);
  GNUNET_free(msg);
  GNUNET_MQ_send(pc->tc->mq, env);
}


/**
 * Client asked to obtain information about a specific or all peers
 * Process the request.
 *
 * @param cls the client
 * @param msg the peer address information request
 */
static void
handle_client_monitor_peers(void *cls, const struct PeerMonitorMessage *msg)
{
  struct TransportClient *tc = cls;
  struct IterationContext pc;

  if (CT_NONE != tc->type)
    {
      GNUNET_break(0);
      GNUNET_SERVICE_client_drop(tc->client);
      return;
    }
  GNUNET_SERVICE_client_disable_continue_warning(tc->client);
  GNUNET_SERVICE_client_mark_monitor(tc->client);

  /* Send initial list */
  pc.tc = tc;
  if (0 == memcmp(&msg->peer, &all_zeros, sizeof(struct GNUNET_PeerIdentity)))
    {
      /* iterate over all neighbours */
      pc.all = GNUNET_YES;
      pc.id = msg->peer;
    }
  else
    {
      /* just return one neighbour */
      pc.all = GNUNET_NO;
      pc.id = msg->peer;
    }
  GST_neighbours_iterate(&send_peer_information, &pc);

  if (GNUNET_YES != ntohl(msg->one_shot))
    {
      tc->details.monitor_peer = msg->peer;
      tc->type = CT_MONITOR;
      if (0 !=
          memcmp(&msg->peer, &all_zeros, sizeof(struct GNUNET_PeerIdentity)))
        GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                   "Client %p started monitoring of the peer `%s'\n",
                   tc,
                   GNUNET_i2s(&msg->peer));
      else
        GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                   "Client %p started monitoring all peers\n",
                   tc);
    }
  else
    {
      struct GNUNET_MessageHeader *msg;
      struct GNUNET_MQ_Envelope *env;

      env =
        GNUNET_MQ_msg(msg,
                      GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_RESPONSE_END);
      GNUNET_MQ_send(tc->mq, env);
    }
}


/**
 * Function called by the plugin with information about the
 * current sessions managed by the plugin (for monitoring).
 *
 * @param cls closure
 * @param session session handle this information is about,
 *        NULL to indicate that we are "in sync" (initial
 *        iteration complete)
 * @param info information about the state of the session,
 *        NULL if @a session is also NULL and we are
 *        merely signalling that the initial iteration is over
 */
static void
plugin_session_info_cb(void *cls,
                       struct GNUNET_ATS_Session *session,
                       const struct GNUNET_TRANSPORT_SessionInfo *info)
{
  struct GNUNET_MQ_Envelope *env;
  struct TransportPluginMonitorMessage *msg;
  struct GNUNET_MessageHeader *sync;
  size_t size;
  size_t slen;
  uint16_t alen;
  char *name;
  char *addr;

  if (0 == GNUNET_notification_context_get_size(plugin_nc))
    {
      GST_plugins_monitor_subscribe(NULL, NULL);
      return;
    }
  if ((NULL == info) && (NULL == session))
    {
      /* end of initial iteration */
      if (NULL != sync_client)
        {
          env =
            GNUNET_MQ_msg(sync, GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PLUGIN_SYNC);
          GNUNET_MQ_send(sync_client->mq, env);
          sync_client = NULL;
        }
      return;
    }
  GNUNET_assert(NULL != info);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Plugin event for peer %s on transport %s\n",
             GNUNET_i2s(&info->address->peer),
             info->address->transport_name);
  slen = strlen(info->address->transport_name) + 1;
  alen = info->address->address_length;
  size = sizeof(struct TransportPluginMonitorMessage) + slen + alen;
  if (size > UINT16_MAX)
    {
      GNUNET_break(0);
      return;
    }
  msg = GNUNET_malloc(size);
  msg->header.size = htons(size);
  msg->header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PLUGIN_EVENT);
  msg->session_state = htons((uint16_t)info->state);
  msg->is_inbound = htons((int16_t)info->is_inbound);
  msg->msgs_pending = htonl(info->num_msg_pending);
  msg->bytes_pending = htonl(info->num_bytes_pending);
  msg->timeout = GNUNET_TIME_absolute_hton(info->session_timeout);
  msg->delay = GNUNET_TIME_absolute_hton(info->receive_delay);
  msg->peer = info->address->peer;
  msg->session_id = (uint64_t)(intptr_t)session;
  msg->plugin_name_len = htons(slen);
  msg->plugin_address_len = htons(alen);
  name = (char *)&msg[1];
  GNUNET_memcpy(name, info->address->transport_name, slen);
  addr = &name[slen];
  GNUNET_memcpy(addr, info->address->address, alen);
  if (NULL != sync_client)
    {
      struct GNUNET_MQ_Envelope *env;

      env = GNUNET_MQ_msg_copy(&msg->header);
      GNUNET_MQ_send(sync_client->mq, env);
    }
  else
    {
      GNUNET_notification_context_broadcast(plugin_nc, &msg->header, GNUNET_NO);
    }
  GNUNET_free(msg);
}


/**
 * Client asked to obtain information about all plugin connections.
 *
 * @param cls the client
 * @param message the peer address information request
 */
static void
handle_client_monitor_plugins(void *cls,
                              const struct GNUNET_MessageHeader *message)
{
  struct TransportClient *tc = cls;

  GNUNET_SERVICE_client_mark_monitor(tc->client);
  GNUNET_SERVICE_client_disable_continue_warning(tc->client);
  GNUNET_notification_context_add(plugin_nc, tc->mq);
  GNUNET_assert(NULL == sync_client);
  sync_client = tc;
  GST_plugins_monitor_subscribe(&plugin_session_info_cb, NULL);
}


/**
 * Broadcast the given message to all of our clients.
 *
 * @param msg message to broadcast
 * @param may_drop #GNUNET_YES if the message can be dropped / is payload
 */
void
GST_clients_broadcast(const struct GNUNET_MessageHeader *msg, int may_drop)
{
  int done;

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Asked to broadcast message of type %u with %u bytes\n",
             (unsigned int)ntohs(msg->type),
             (unsigned int)ntohs(msg->size));
  done = GNUNET_NO;
  for (struct TransportClient *tc = clients_head; NULL != tc; tc = tc->next)
    {
      if (CT_NONE == tc->type)
        continue; /* client not yet ready */
      if ((GNUNET_YES == may_drop) && (CT_CORE != tc->type))
        continue; /* skip, this client does not care about payload */
      unicast(tc, msg, may_drop);
      done = GNUNET_YES;
    }
  if (GNUNET_NO == done)
    GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
               "Message of type %u not delivered, is CORE service up?\n",
               ntohs(msg->type));
}


/**
 * Broadcast the new active address to all clients monitoring the peer.
 *
 * @param peer peer this update is about (never NULL)
 * @param address address, NULL on disconnect
 * @param state the current state of the peer
 * @param state_timeout the time out for the state
 */
void
GST_clients_broadcast_peer_notification(
  const struct GNUNET_PeerIdentity *peer,
  const struct GNUNET_HELLO_Address *address,
  enum GNUNET_TRANSPORT_PeerState state,
  struct GNUNET_TIME_Absolute state_timeout)
{
  struct GNUNET_MQ_Envelope *env;
  struct PeerIterateResponseMessage *msg;

  msg = compose_address_iterate_response_message(peer, address);
  msg->state = htonl(state);
  msg->state_timeout = GNUNET_TIME_absolute_hton(state_timeout);
  for (struct TransportClient *tc = clients_head; NULL != tc; tc = tc->next)
    {
      if (CT_MONITOR != tc->type)
        continue;
      if ((0 == memcmp(&tc->details.monitor_peer,
                       &all_zeros,
                       sizeof(struct GNUNET_PeerIdentity))) ||
          (0 == memcmp(&tc->details.monitor_peer,
                       peer,
                       sizeof(struct GNUNET_PeerIdentity))))
        {
          env = GNUNET_MQ_msg_copy(&msg->header);
          GNUNET_MQ_send(tc->mq, env);
        }
    }
  GNUNET_free(msg);
}


/**
 * Mark the peer as down so we don't call the continuation
 * context in the future.
 *
 * @param cls NULL
 * @param peer peer that got disconnected
 * @param value a `struct SendTransmitContinuationContext` to mark
 * @return #GNUNET_OK (continue to iterate)
 */
static int
mark_peer_down(void *cls, const struct GNUNET_PeerIdentity *peer, void *value)
{
  struct SendTransmitContinuationContext *stcc = value;

  stcc->down = GNUNET_YES;
  return GNUNET_OK;
}


/**
 * Notify all clients about a disconnect, and cancel
 * pending SEND_OK messages for this peer.
 *
 * @param peer peer that disconnected
 */
void
GST_clients_broadcast_disconnect(const struct GNUNET_PeerIdentity *peer)
{
  struct DisconnectInfoMessage disconnect_msg;

  GNUNET_CONTAINER_multipeermap_get_multiple(active_stccs,
                                             peer,
                                             &mark_peer_down,
                                             NULL);
  disconnect_msg.header.size = htons(sizeof(struct DisconnectInfoMessage));
  disconnect_msg.header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_DISCONNECT);
  disconnect_msg.reserved = htonl(0);
  disconnect_msg.peer = *peer;
  GST_clients_broadcast(&disconnect_msg.header, GNUNET_NO);
}


/**
 * Transmit our HELLO message to the given (connected) neighbour.
 *
 * @param cls the 'HELLO' message
 * @param peer identity of the peer
 * @param address the address
 * @param state current state this peer is in
 * @param state_timeout timeout for the current state of the peer
 * @param bandwidth_in inbound quota in NBO
 * @param bandwidth_out outbound quota in NBO
 */
static void
transmit_our_hello(void *cls,
                   const struct GNUNET_PeerIdentity *peer,
                   const struct GNUNET_HELLO_Address *address,
                   enum GNUNET_TRANSPORT_PeerState state,
                   struct GNUNET_TIME_Absolute state_timeout,
                   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
                   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
{
  const struct GNUNET_MessageHeader *hello = cls;

  if (0 == memcmp(peer, &GST_my_identity, sizeof(struct GNUNET_PeerIdentity)))
    return; /* not to ourselves */
  if (GNUNET_NO == GST_neighbours_test_connected(peer))
    return;

  GST_neighbours_send(peer,
                      hello,
                      ntohs(hello->size),
                      hello_expiration,
                      NULL,
                      NULL);
}


/**
 * My HELLO has changed. Tell everyone who should know.
 *
 * @param cls unused
 * @param hello new HELLO
 */
static void
process_hello_update(void *cls, const struct GNUNET_MessageHeader *hello)
{
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Broadcasting HELLO to clients\n");
  GST_clients_broadcast(hello, GNUNET_NO);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Broadcasting HELLO to neighbours\n");
  GST_neighbours_iterate(&transmit_our_hello, (void *)hello);
}


/**
 * We received some payload.  Prepare to pass it on to our clients.
 *
 * @param address address and (claimed) identity of the other peer
 * @param session identifier used for this session (NULL for plugins
 *                that do not offer bi-directional communication to the sender
 *                using the same "connection")
 * @param message the message to process
 * @return how long the plugin should wait until receiving more data
 */
static struct GNUNET_TIME_Relative
process_payload(const struct GNUNET_HELLO_Address *address,
                struct GNUNET_ATS_Session *session,
                const struct GNUNET_MessageHeader *message)
{
  struct GNUNET_TIME_Relative ret;
  int do_forward;
  struct InboundMessage *im;
  size_t msg_size = ntohs(message->size);
  size_t size = sizeof(struct InboundMessage) + msg_size;
  char buf[size] GNUNET_ALIGN;

  do_forward = GNUNET_SYSERR;
  ret = GST_neighbours_calculate_receive_delay(&address->peer,
                                               msg_size,
                                               &do_forward);
  if (!GST_neighbours_test_connected(&address->peer))
    {
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "Discarded %u bytes type %u payload from peer `%s'\n",
                 (unsigned int)msg_size,
                 ntohs(message->type),
                 GNUNET_i2s(&address->peer));
      GNUNET_STATISTICS_update(
        GST_stats,
        gettext_noop("# bytes payload discarded due to not connected peer"),
        msg_size,
        GNUNET_NO);
      return ret;
    }

  if (GNUNET_YES != do_forward)
    return ret;
  im = (struct InboundMessage *)buf;
  im->header.size = htons(size);
  im->header.type = htons(GNUNET_MESSAGE_TYPE_TRANSPORT_RECV);
  im->peer = address->peer;
  GNUNET_memcpy(&im[1], message, ntohs(message->size));
  GST_clients_broadcast(&im->header, GNUNET_YES);
  return ret;
}


/**
 * Task to asynchronously terminate a session.
 *
 * @param cls the `struct GNUNET_ATS_SessionKiller` with the information for the kill
 */
static void
kill_session_task(void *cls)
{
  struct GNUNET_ATS_SessionKiller *sk = cls;

  sk->task = NULL;
  GNUNET_CONTAINER_DLL_remove(sk_head, sk_tail, sk);
  sk->plugin->disconnect_session(sk->plugin->cls, sk->session);
  GNUNET_free(sk);
}


/**
 * Force plugin to terminate session due to communication
 * issue.
 *
 * @param plugin_name name of the plugin
 * @param session session to termiante
 */
static void
kill_session(const char *plugin_name, struct GNUNET_ATS_Session *session)
{
  struct GNUNET_TRANSPORT_PluginFunctions *plugin;
  struct GNUNET_ATS_SessionKiller *sk;

  for (sk = sk_head; NULL != sk; sk = sk->next)
    if (sk->session == session)
      return;
  plugin = GST_plugins_find(plugin_name);
  if (NULL == plugin)
    {
      GNUNET_break(0);
      return;
    }
  /* need to issue disconnect asynchronously */
  sk = GNUNET_new(struct GNUNET_ATS_SessionKiller);
  sk->session = session;
  sk->plugin = plugin;
  sk->task = GNUNET_SCHEDULER_add_now(&kill_session_task, sk);
  GNUNET_CONTAINER_DLL_insert(sk_head, sk_tail, sk);
}


/**
 * Black list check result for try_connect call
 * If connection to the peer is allowed request adddress and ???
 *
 * @param cls the message
 * @param peer the peer
 * @param address the address
 * @param session the session
 * @param result the result
 */
static void
connect_bl_check_cont(void *cls,
                      const struct GNUNET_PeerIdentity *peer,
                      const struct GNUNET_HELLO_Address *address,
                      struct GNUNET_ATS_Session *session,
                      int result)
{
  struct GNUNET_MessageHeader *msg = cls;

  if (GNUNET_OK == result)
    {
      /* Blacklist allows to speak to this peer, forward SYN to neighbours  */
      GNUNET_log(GNUNET_ERROR_TYPE_INFO,
                 "Received SYN message from peer `%s' at `%s'\n",
                 GNUNET_i2s(peer),
                 GST_plugins_a2s(address));
      if (GNUNET_OK != GST_neighbours_handle_session_syn(msg, peer))
        {
          GST_blacklist_abort_matching(address, session);
          kill_session(address->transport_name, session);
        }
      GNUNET_free(msg);
      return;
    }
  GNUNET_free(msg);
  if (GNUNET_SYSERR == result)
    return; /* check was aborted, session destroyed */
  /* Blacklist denies to speak to this peer */
  GNUNET_log(GNUNET_ERROR_TYPE_INFO,
             "Discarding SYN message from `%s' due to denied blacklist check\n",
             GNUNET_i2s(peer));
  kill_session(address->transport_name, session);
}


/**
 * Function called by the transport for each received message.
 *
 * @param cls closure, const char* with the name of the plugin we received the message from
 * @param address address and (claimed) identity of the other peer
 * @param message the message, NULL if we only care about
 *                learning about the delay until we should receive again
 * @param session identifier used for this session (NULL for plugins
 *                that do not offer bi-directional communication to the sender
 *                using the same "connection")
 * @return how long the plugin should wait until receiving more data
 *         (plugins that do not support this, can ignore the return value)
 */
struct GNUNET_TIME_Relative
GST_receive_callback(void *cls,
                     const struct GNUNET_HELLO_Address *address,
                     struct GNUNET_ATS_Session *session,
                     const struct GNUNET_MessageHeader *message)
{
  const char *plugin_name = cls;
  struct GNUNET_TIME_Relative ret;
  uint16_t type;

  ret = GNUNET_TIME_UNIT_ZERO;
  if (NULL == message)
    goto end;
  type = ntohs(message->type);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Received message with type %u from peer `%s' at %s\n",
             type,
             GNUNET_i2s(&address->peer),
             GST_plugins_a2s(address));

  GNUNET_STATISTICS_update(GST_stats,
                           gettext_noop("# bytes total received"),
                           ntohs(message->size),
                           GNUNET_NO);
  GST_neighbours_notify_data_recv(address, message);
  switch (type)
    {
    case GNUNET_MESSAGE_TYPE_HELLO_LEGACY:
      /* Legacy HELLO message, discard  */
      return ret;

    case GNUNET_MESSAGE_TYPE_HELLO:
      if (GNUNET_OK != GST_validation_handle_hello(message))
        {
          GNUNET_break_op(0);
          GST_blacklist_abort_matching(address, session);
        }
      return ret;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_PING:
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "Processing PING from `%s'\n",
                 GST_plugins_a2s(address));
      if (GNUNET_OK !=
          GST_validation_handle_ping(&address->peer, message, address, session))
        {
          GST_blacklist_abort_matching(address, session);
          kill_session(plugin_name, session);
        }
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_PONG:
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "Processing PONG from `%s'\n",
                 GST_plugins_a2s(address));
      if (GNUNET_OK != GST_validation_handle_pong(&address->peer, message))
        {
          GNUNET_break_op(0);
          GST_blacklist_abort_matching(address, session);
          kill_session(plugin_name, session);
        }
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN:
      /* Do blacklist check if communication with this peer is allowed */
      (void)GST_blacklist_test_allowed(&address->peer,
                                       NULL,
                                       &connect_bl_check_cont,
                                       GNUNET_copy_message(message),
                                       address,
                                       session);
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN_ACK:
      if (GNUNET_OK !=
          GST_neighbours_handle_session_syn_ack(message, address, session))
        {
          GST_blacklist_abort_matching(address, session);
          kill_session(plugin_name, session);
        }
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_ACK:
      if (GNUNET_OK !=
          GST_neighbours_handle_session_ack(message, address, session))
        {
          GNUNET_break_op(0);
          GST_blacklist_abort_matching(address, session);
          kill_session(plugin_name, session);
        }
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT:
      GST_neighbours_handle_disconnect_message(&address->peer, message);
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_QUOTA:
      GST_neighbours_handle_quota_message(&address->peer, message);
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE:
      GST_neighbours_keepalive(&address->peer, message);
      break;

    case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE_RESPONSE:
      GST_neighbours_keepalive_response(&address->peer, message);
      break;

    default:
      /* should be payload */
      GNUNET_STATISTICS_update(GST_stats,
                               gettext_noop("# bytes payload received"),
                               ntohs(message->size),
                               GNUNET_NO);
      ret = process_payload(address, session, message);
      break;
    }
end:
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Allowing receive from peer %s to continue in %s\n",
             GNUNET_i2s(&address->peer),
             GNUNET_STRINGS_relative_time_to_string(ret, GNUNET_YES));
  return ret;
}


/**
 * Function that will be called for each address the transport
 * is aware that it might be reachable under.  Update our HELLO.
 *
 * @param cls name of the plugin (const char*)
 * @param add_remove should the address added (YES) or removed (NO) from the
 *                   set of valid addresses?
 * @param address the address to add or remove
 */
static void
plugin_env_address_change_notification(
  void *cls,
  int add_remove,
  const struct GNUNET_HELLO_Address *address)
{
  static int addresses = 0;

  if (GNUNET_YES == add_remove)
    {
      addresses++;
      GNUNET_STATISTICS_update(GST_stats, "# transport addresses", 1, GNUNET_NO);
    }
  else if (GNUNET_NO == add_remove)
    {
      if (0 == addresses)
        {
          GNUNET_break(0);
        }
      else
        {
          addresses--;
          GNUNET_STATISTICS_update(GST_stats,
                                   "# transport addresses",
                                   -1,
                                   GNUNET_NO);
        }
    }
  GNUNET_log(GNUNET_ERROR_TYPE_INFO,
             "Transport now has %u addresses to communicate\n",
             addresses);
  GST_hello_modify_addresses(add_remove, address);
}


/**
 * Function that will be called whenever the plugin internally
 * cleans up a session pointer and hence the service needs to
 * discard all of those sessions as well.  Plugins that do not
 * use sessions can simply omit calling this function and always
 * use NULL wherever a session pointer is needed.  This function
 * should be called BEFORE a potential "TransmitContinuation"
 * from the "TransmitFunction".
 *
 * @param cls closure
 * @param address which address was the session for
 * @param session which session is being destoyed
 */
static void
plugin_env_session_end(void *cls,
                       const struct GNUNET_HELLO_Address *address,
                       struct GNUNET_ATS_Session *session)
{
  struct GNUNET_ATS_SessionKiller *sk;

  if (NULL == address)
    {
      GNUNET_break(0);
      return;
    }
  if (NULL == session)
    {
      GNUNET_break(0);
      return;
    }
  GNUNET_assert(strlen(address->transport_name) > 0);

  GNUNET_log(
    GNUNET_ERROR_TYPE_DEBUG,
    "Notification from plugin about terminated session %p from peer `%s' address `%s'\n",
    session,
    GNUNET_i2s(&address->peer),
    GST_plugins_a2s(address));

  GST_neighbours_session_terminated(&address->peer, session);
  GST_ats_del_session(address, session);
  GST_blacklist_abort_matching(address, session);

  for (sk = sk_head; NULL != sk; sk = sk->next)
    {
      if (sk->session == session)
        {
          GNUNET_CONTAINER_DLL_remove(sk_head, sk_tail, sk);
          GNUNET_SCHEDULER_cancel(sk->task);
          GNUNET_free(sk);
          break;
        }
    }
}


/**
 * Black list check result from blacklist check triggered when a
 * plugin gave us a new session in #plugin_env_session_start().  If
 * connection to the peer is disallowed, kill the session.
 *
 * @param cls NULL
 * @param peer the peer
 * @param address address associated with the request
 * @param session session associated with the request
 * @param result the result
 */
static void
plugin_env_session_start_bl_check_cont(
  void *cls,
  const struct GNUNET_PeerIdentity *peer,
  const struct GNUNET_HELLO_Address *address,
  struct GNUNET_ATS_Session *session,
  int result)
{
  if (GNUNET_OK != result)
    {
      kill_session(address->transport_name, session);
      return;
    }
  if (GNUNET_YES !=
      GNUNET_HELLO_address_check_option(address,
                                        GNUNET_HELLO_ADDRESS_INFO_INBOUND))
    {
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "Informing verifier about inbound session's address `%s'\n",
                 GST_plugins_a2s(address));
      GST_validation_handle_address(address);
    }
}


/**
 * Plugin tells transport service about a new inbound session
 *
 * @param cls unused
 * @param address the address
 * @param session the new session
 * @param scope network scope information
 */
static void
plugin_env_session_start(void *cls,
                         const struct GNUNET_HELLO_Address *address,
                         struct GNUNET_ATS_Session *session,
                         enum GNUNET_NetworkType scope)
{
  struct GNUNET_ATS_Properties prop;

  if (NULL == address)
    {
      GNUNET_break(0);
      return;
    }
  if (NULL == session)
    {
      GNUNET_break(0);
      return;
    }
  GNUNET_log(
    GNUNET_ERROR_TYPE_INFO,
    "Notification from plugin `%s' about new session from peer `%s' address `%s'\n",
    address->transport_name,
    GNUNET_i2s(&address->peer),
    GST_plugins_a2s(address));
  if (GNUNET_YES ==
      GNUNET_HELLO_address_check_option(address,
                                        GNUNET_HELLO_ADDRESS_INFO_INBOUND))
    {
      /* inbound is always new, but outbound MAY already be known, but
         for example for UNIX, we have symmetric connections and thus we
         may not know the address yet; add if necessary! */
      /* FIXME: maybe change API here so we just pass scope? */
      memset(&prop, 0, sizeof(prop));
      GNUNET_break(GNUNET_NT_UNSPECIFIED != scope);
      prop.scope = scope;
      GST_ats_add_inbound_address(address, session, &prop);
    }
  /* Do blacklist check if communication with this peer is allowed */
  (void)GST_blacklist_test_allowed(&address->peer,
                                   address->transport_name,
                                   &plugin_env_session_start_bl_check_cont,
                                   NULL,
                                   address,
                                   session);
}


/**
 * Function called by ATS to notify the callee that the
 * assigned bandwidth or address for a given peer was changed.  If the
 * callback is called with address/bandwidth assignments of zero, the
 * ATS disconnect function will still be called once the disconnect
 * actually happened.
 *
 * @param cls closure
 * @param peer the peer this address is intended for
 * @param address address to use (for peer given in address)
 * @param session session to use (if available)
 * @param bandwidth_out assigned outbound bandwidth for the connection in NBO,
 *      0 to disconnect from peer
 * @param bandwidth_in assigned inbound bandwidth for the connection in NBO,
 *      0 to disconnect from peer
 * @param ats ATS information
 * @param ats_count number of @a ats elements
 */
static void
ats_request_address_change(void *cls,
                           const struct GNUNET_PeerIdentity *peer,
                           const struct GNUNET_HELLO_Address *address,
                           struct GNUNET_ATS_Session *session,
                           struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out,
                           struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in)
{
  uint32_t bw_in = ntohl(bandwidth_in.value__);
  uint32_t bw_out = ntohl(bandwidth_out.value__);

  if (NULL == peer)
    {
      /* ATS service died, all suggestions become invalid!
         (but we'll keep using the allocations for a little
         while, to keep going while ATS restarts) */
      /* FIXME: We should drop all
         connections now, as ATS won't explicitly tell
         us and be unaware of ongoing resource allocations! */
      return;
    }
  /* ATS tells me to disconnect from peer */
  if ((0 == bw_in) && (0 == bw_out))
    {
      GNUNET_log(GNUNET_ERROR_TYPE_INFO,
                 "ATS tells me to disconnect from peer `%s'\n",
                 GNUNET_i2s(peer));
      GST_neighbours_force_disconnect(peer);
      return;
    }
  GNUNET_assert(NULL != address);
  GNUNET_STATISTICS_update(GST_stats,
                           "# ATS suggestions received",
                           1,
                           GNUNET_NO);
  GST_neighbours_switch_to_address(address,
                                   session,
                                   bandwidth_in,
                                   bandwidth_out);
}


/**
 * Closure for #test_connection_ok().
 */
struct TestConnectionContext {
  /**
   * Is this the first neighbour we're checking?
   */
  int first;

  /**
   * Handle to the blacklisting client we need to ask.
   */
  struct TransportClient *tc;
};


/**
 * Got the result about an existing connection from a new blacklister.
 * Shutdown the neighbour if necessary.
 *
 * @param cls unused
 * @param peer the neighbour that was investigated
 * @param address address associated with the request
 * @param session session associated with the request
 * @param allowed #GNUNET_OK if we can keep it,
 *                #GNUNET_NO if we must shutdown the connection
 */
static void
confirm_or_drop_neighbour(void *cls,
                          const struct GNUNET_PeerIdentity *peer,
                          const struct GNUNET_HELLO_Address *address,
                          struct GNUNET_ATS_Session *session,
                          int allowed)
{
  if (GNUNET_OK == allowed)
    return; /* we're done */
  GNUNET_STATISTICS_update(GST_stats,
                           gettext_noop("# disconnects due to blacklist"),
                           1,
                           GNUNET_NO);
  GST_neighbours_force_disconnect(peer);
}


/**
 * Test if an existing connection is still acceptable given a new
 * blacklisting client.
 *
 * @param cls the `struct TestConnectionContext *`
 * @param peer identity of the peer
 * @param address the address
 * @param state current state this peer is in
 * @param state_timeout timeout for the current state of the peer
 * @param bandwidth_in bandwidth assigned inbound
 * @param bandwidth_out bandwidth assigned outbound
 */
static void
test_connection_ok(void *cls,
                   const struct GNUNET_PeerIdentity *peer,
                   const struct GNUNET_HELLO_Address *address,
                   enum GNUNET_TRANSPORT_PeerState state,
                   struct GNUNET_TIME_Absolute state_timeout,
                   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
                   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
{
  struct TestConnectionContext *tcc = cls;
  struct GST_BlacklistCheck *bc;

  bc = GNUNET_new(struct GST_BlacklistCheck);
  GNUNET_CONTAINER_DLL_insert(bc_head, bc_tail, bc);
  bc->peer = *peer;
  bc->address = GNUNET_HELLO_address_copy(address);
  bc->cont = &confirm_or_drop_neighbour;
  bc->cont_cls = NULL;
  bc->bl_pos = tcc->tc;
  if (GNUNET_YES == tcc->first)
    {
      /* all would wait for the same client, no need to
       * create more than just the first task right now */
      bc->task = GNUNET_SCHEDULER_add_now(&do_blacklist_check, bc);
      tcc->first = GNUNET_NO;
    }
}


/**
 * Initialize a blacklisting client.  We got a blacklist-init
 * message from this client, add it to the list of clients
 * to query for blacklisting.
 *
 * @param cls the client
 * @param message the blacklist-init message that was sent
 */
static void
handle_client_blacklist_init(void *cls,
                             const struct GNUNET_MessageHeader *message)
{
  struct TransportClient *tc = cls;
  struct TestConnectionContext tcc;

  if (CT_NONE != tc->type)
    {
      GNUNET_break(0);
      GNUNET_SERVICE_client_drop(tc->client);
      return;
    }
  GNUNET_SERVICE_client_mark_monitor(tc->client);
  tc->type = CT_BLACKLIST;
  tc->details.blacklist.call_receive_done = GNUNET_YES;
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "New blacklist client %p\n", tc);
  /* confirm that all existing connections are OK! */
  tcc.tc = tc;
  tcc.first = GNUNET_YES;
  GST_neighbours_iterate(&test_connection_ok, &tcc);
}


/**
 * Free the given entry in the blacklist.
 *
 * @param cls unused
 * @param key host identity (unused)
 * @param value the blacklist entry
 * @return #GNUNET_OK (continue to iterate)
 */
static int
free_blacklist_entry(void *cls,
                     const struct GNUNET_PeerIdentity *key,
                     void *value)
{
  char *be = value;

  GNUNET_free_non_null(be);
  return GNUNET_OK;
}


/**
 * Set traffic metric to manipulate
 *
 * @param cls closure
 * @param message containing information
 */
static void
handle_client_set_metric(void *cls, const struct TrafficMetricMessage *tm)
{
  struct TransportClient *tc = cls;

  GST_manipulation_set_metric(tm);
  GNUNET_SERVICE_client_continue(tc->client);
}


/**
 * Function called when the service shuts down.  Unloads our plugins
 * and cancels pending validations.
 *
 * @param cls closure, unused
 */
static void
shutdown_task(void *cls)
{
  struct AddressToStringContext *cur;

  GST_neighbours_stop();
  GST_plugins_unload();
  GST_validation_stop();
  GST_ats_done();
  GNUNET_ATS_scheduling_done(GST_ats);
  GST_ats = NULL;
  GNUNET_ATS_connectivity_done(GST_ats_connect);
  GST_ats_connect = NULL;
  GNUNET_NT_scanner_done(GST_is);
  GST_is = NULL;
  while (NULL != (cur = a2s_head))
    {
      GNUNET_CONTAINER_DLL_remove(a2s_head, a2s_tail, cur);
      GNUNET_free(cur);
    }
  if (NULL != plugin_nc)
    {
      GNUNET_notification_context_destroy(plugin_nc);
      plugin_nc = NULL;
    }
  GNUNET_CONTAINER_multipeermap_destroy(active_stccs);
  active_stccs = NULL;
  if (NULL != blacklist)
    {
      GNUNET_CONTAINER_multipeermap_iterate(blacklist,
                                            &free_blacklist_entry,
                                            NULL);
      GNUNET_CONTAINER_multipeermap_destroy(blacklist);
      blacklist = NULL;
    }
  GST_hello_stop();
  GST_manipulation_stop();

  if (NULL != GST_peerinfo)
    {
      GNUNET_PEERINFO_disconnect(GST_peerinfo);
      GST_peerinfo = NULL;
    }
  if (NULL != GST_stats)
    {
      GNUNET_STATISTICS_destroy(GST_stats, GNUNET_NO);
      GST_stats = NULL;
    }
  if (NULL != GST_my_private_key)
    {
      GNUNET_free(GST_my_private_key);
      GST_my_private_key = NULL;
    }
}


/**
 * Perform next action in the blacklist check.
 *
 * @param cls the `struct GST_BlacklistCheck *`
 */
static void
do_blacklist_check(void *cls)
{
  struct GST_BlacklistCheck *bc = cls;
  struct TransportClient *tc;
  struct GNUNET_MQ_Envelope *env;
  struct BlacklistMessage *bm;

  bc->task = NULL;
  while (NULL != (tc = bc->bl_pos))
    {
      if (CT_BLACKLIST == tc->type)
        break;
      bc->bl_pos = tc->next;
    }
  if (NULL == tc)
    {
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "No other blacklist clients active, will allow neighbour `%s'\n",
                 GNUNET_i2s(&bc->peer));

      bc->cont(bc->cont_cls, &bc->peer, bc->address, bc->session, GNUNET_OK);
      GST_blacklist_test_cancel(bc);
      return;
    }
  if ((NULL != tc->details.blacklist.bc) ||
      (GNUNET_NO != tc->details.blacklist.waiting_for_reply))
    return; /* someone else busy with this client */
  tc->details.blacklist.bc = bc;
  env = GNUNET_MQ_msg(bm, GNUNET_MESSAGE_TYPE_TRANSPORT_BLACKLIST_QUERY);
  bm->is_allowed = htonl(0);
  bm->peer = bc->peer;
  GNUNET_MQ_send(tc->mq, env);
  if (GNUNET_YES == tc->details.blacklist.call_receive_done)
    {
      tc->details.blacklist.call_receive_done = GNUNET_NO;
      GNUNET_SERVICE_client_continue(tc->client);
    }
  tc->details.blacklist.waiting_for_reply = GNUNET_YES;
}


/**
 * A blacklisting client has sent us reply. Process it.
 *
 * @param cls the client
 * @param msg the blacklist-reply message that was sent
 */
static void
handle_client_blacklist_reply(void *cls, const struct BlacklistMessage *msg)
{
  struct TransportClient *tc = cls;
  struct GST_BlacklistCheck *bc;

  if (CT_BLACKLIST != tc->type)
    {
      GNUNET_break(0);
      GNUNET_SERVICE_client_drop(tc->client);
      return;
    }
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Blacklist client %p sent reply for `%s'\n",
             tc,
             GNUNET_i2s(&msg->peer));
  bc = tc->details.blacklist.bc;
  tc->details.blacklist.bc = NULL;
  tc->details.blacklist.waiting_for_reply = GNUNET_NO;
  tc->details.blacklist.call_receive_done = GNUNET_YES;
  if (NULL != bc)
    {
      /* only run this if the blacklist check has not been
       * cancelled in the meantime... */
      GNUNET_assert(bc->bl_pos == tc);
      if (ntohl(msg->is_allowed) == GNUNET_SYSERR)
        {
          GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                     "Blacklist check failed, peer not allowed\n");
          /* For the duration of the continuation, make the ongoing
             check invisible (to avoid double-cancellation); then
             add it back again so we can re-use GST_blacklist_test_cancel() */
          GNUNET_CONTAINER_DLL_remove(bc_head, bc_tail, bc);
          bc->cont(bc->cont_cls, &bc->peer, bc->address, bc->session, GNUNET_NO);
          GNUNET_CONTAINER_DLL_insert(bc_head, bc_tail, bc);
          GST_blacklist_test_cancel(bc);
          tc->details.blacklist.call_receive_done = GNUNET_NO;
          GNUNET_SERVICE_client_continue(tc->client);
          return;
        }
      else
        {
          GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                     "Blacklist check succeeded, continuing with checks\n");
          tc->details.blacklist.call_receive_done = GNUNET_NO;
          GNUNET_SERVICE_client_continue(tc->client);
          bc->bl_pos = tc->next;
          bc->task = GNUNET_SCHEDULER_add_now(&do_blacklist_check, bc);
        }
    }
  /* check if any other blacklist checks are waiting for this blacklister */
  for (bc = bc_head; bc != NULL; bc = bc->next)
    if ((bc->bl_pos == tc) && (NULL == bc->task))
      {
        bc->task = GNUNET_SCHEDULER_add_now(&do_blacklist_check, bc);
        break;
      }
}


/**
 * Add the given peer to the blacklist (for the given transport).
 *
 * @param peer peer to blacklist
 * @param transport_name transport to blacklist for this peer, NULL for all
 */
void
GST_blacklist_add_peer(const struct GNUNET_PeerIdentity *peer,
                       const char *transport_name)
{
  char *transport = NULL;

  if (NULL != transport_name)
    {
      GNUNET_log(GNUNET_ERROR_TYPE_INFO,
                 "Adding peer `%s' with plugin `%s' to blacklist\n",
                 GNUNET_i2s(peer),
                 transport_name);
      transport = GNUNET_strdup(transport_name);
    }
  else
    GNUNET_log(GNUNET_ERROR_TYPE_INFO,
               "Adding peer `%s' with all plugins to blacklist\n",
               GNUNET_i2s(peer));
  if (NULL == blacklist)
    blacklist =
      GNUNET_CONTAINER_multipeermap_create(TRANSPORT_BLACKLIST_HT_SIZE,
                                           GNUNET_NO);

  GNUNET_CONTAINER_multipeermap_put(blacklist,
                                    peer,
                                    transport,
                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
}


/**
 * Abort blacklist if @a address and @a session match.
 *
 * @param address address used to abort matching checks
 * @param session session used to abort matching checks
 */
void
GST_blacklist_abort_matching(const struct GNUNET_HELLO_Address *address,
                             struct GNUNET_ATS_Session *session)
{
  struct GST_BlacklistCheck *bc;
  struct GST_BlacklistCheck *n;

  n = bc_head;
  while (NULL != (bc = n))
    {
      n = bc->next;
      if ((bc->session == session) &&
          (0 == GNUNET_HELLO_address_cmp(bc->address, address)))
        {
          bc->cont(bc->cont_cls,
                   &bc->peer,
                   bc->address,
                   bc->session,
                   GNUNET_SYSERR);
          GST_blacklist_test_cancel(bc);
        }
    }
}


/**
 * Test if the given blacklist entry matches.  If so,
 * abort the iteration.
 *
 * @param cls the transport name to match (const char*)
 * @param key the key (unused)
 * @param value the 'char *' (name of a blacklisted transport)
 * @return #GNUNET_OK if the entry does not match, #GNUNET_NO if it matches
 */
static int
test_blacklisted(void *cls, const struct GNUNET_PeerIdentity *key, void *value)
{
  const char *transport_name = cls;
  char *be = value;

  /* Blacklist entry be:
   *  (NULL == be): peer is blacklisted with all plugins
   *  (NULL != be): peer is blacklisted for a specific plugin
   *
   * If (NULL != transport_name) we look for a transport specific entry:
   *  if (transport_name == be) forbidden
   *
   */

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Comparing BL request for peer `%4s':`%s' with BL entry: `%s'\n",
             GNUNET_i2s(key),
             (NULL == transport_name) ? "unspecified" : transport_name,
             (NULL == be) ? "all plugins" : be);
  /* all plugins for this peer were blacklisted: disallow */
  if (NULL == value)
    return GNUNET_NO;

  /* blacklist check for specific transport */
  if ((NULL != transport_name) && (NULL != value))
    {
      if (0 == strcmp(transport_name, be))
        return GNUNET_NO; /* plugin is blacklisted! */
    }
  return GNUNET_OK;
}


/**
 * Test if a peer/transport combination is blacklisted.
 *
 * @param peer the identity of the peer to test
 * @param transport_name name of the transport to test, never NULL
 * @param cont function to call with result
 * @param cont_cls closure for @a cont
 * @param address address to pass back to @a cont, can be NULL
 * @param session session to pass back to @a cont, can be NULL
 * @return handle to the blacklist check, NULL if the decision
 *        was made instantly and @a cont was already called
 */
struct GST_BlacklistCheck *
GST_blacklist_test_allowed(const struct GNUNET_PeerIdentity *peer,
                           const char *transport_name,
                           GST_BlacklistTestContinuation cont,
                           void *cont_cls,
                           const struct GNUNET_HELLO_Address *address,
                           struct GNUNET_ATS_Session *session)
{
  struct GST_BlacklistCheck *bc;
  struct TransportClient *tc;

  GNUNET_assert(NULL != peer);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Blacklist check for peer `%s':%s\n",
             GNUNET_i2s(peer),
             (NULL != transport_name) ? transport_name : "unspecified");

  /* Check local blacklist by iterating over hashmap
   * If iteration is aborted, we found a matching blacklist entry */
  if ((NULL != blacklist) &&
      (GNUNET_SYSERR ==
       GNUNET_CONTAINER_multipeermap_get_multiple(blacklist,
                                                  peer,
                                                  &test_blacklisted,
                                                  (void *)transport_name)))
    {
      /* Disallowed by config, disapprove instantly */
      GNUNET_STATISTICS_update(GST_stats,
                               gettext_noop("# disconnects due to blacklist"),
                               1,
                               GNUNET_NO);
      GNUNET_log(GNUNET_ERROR_TYPE_INFO,
                 _("Disallowing connection to peer `%s' on transport %s\n"),
                 GNUNET_i2s(peer),
                 (NULL != transport_name) ? transport_name : "unspecified");
      if (NULL != cont)
        cont(cont_cls, peer, address, session, GNUNET_NO);
      return NULL;
    }

  for (tc = clients_head; NULL != tc; tc = tc->next)
    if (CT_BLACKLIST == tc->type)
      break;
  if (NULL == tc)
    {
      /* no blacklist clients, approve instantly */
      if (NULL != cont)
        cont(cont_cls, peer, address, session, GNUNET_OK);
      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                 "Allowing connection to peer `%s' %s\n",
                 GNUNET_i2s(peer),
                 (NULL != transport_name) ? transport_name : "");
      return NULL;
    }

  /* need to query blacklist clients */
  bc = GNUNET_new(struct GST_BlacklistCheck);
  GNUNET_CONTAINER_DLL_insert(bc_head, bc_tail, bc);
  bc->peer = *peer;
  bc->address = GNUNET_HELLO_address_copy(address);
  bc->session = session;
  bc->cont = cont;
  bc->cont_cls = cont_cls;
  bc->bl_pos = tc;
  bc->task = GNUNET_SCHEDULER_add_now(&do_blacklist_check, bc);
  return bc;
}


/**
 * Cancel a blacklist check.
 *
 * @param bc check to cancel
 */
void
GST_blacklist_test_cancel(struct GST_BlacklistCheck *bc)
{
  GNUNET_CONTAINER_DLL_remove(bc_head, bc_tail, bc);
  if (NULL != bc->bl_pos)
    {
      if ((CT_BLACKLIST == bc->bl_pos->type) &&
          (bc->bl_pos->details.blacklist.bc == bc))
        {
          /* we're at the head of the queue, remove us! */
          bc->bl_pos->details.blacklist.bc = NULL;
        }
    }
  if (NULL != bc->task)
    {
      GNUNET_SCHEDULER_cancel(bc->task);
      bc->task = NULL;
    }
  GNUNET_free_non_null(bc->address);
  GNUNET_free(bc);
}


/**
 * Function to iterate over options in the blacklisting section for a peer.
 *
 * @param cls closure
 * @param section name of the section
 * @param option name of the option
 * @param value value of the option
 */
static void
blacklist_cfg_iter(void *cls,
                   const char *section,
                   const char *option,
                   const char *value)
{
  unsigned int *res = cls;
  struct GNUNET_PeerIdentity peer;
  char *plugs;
  char *pos;

  if (GNUNET_OK !=
      GNUNET_CRYPTO_eddsa_public_key_from_string(option,
                                                 strlen(option),
                                                 &peer.public_key))
    return;

  if ((NULL == value) || (0 == strcmp(value, "")))
    {
      /* Blacklist whole peer */
      GST_blacklist_add_peer(&peer, NULL);
      GNUNET_log(GNUNET_ERROR_TYPE_INFO,
                 _("Adding blacklisting entry for peer `%s'\n"),
                 GNUNET_i2s(&peer));
    }
  else
    {
      plugs = GNUNET_strdup(value);
      for (pos = strtok(plugs, " "); pos != NULL; pos = strtok(NULL, " "))
        {
          GNUNET_log(GNUNET_ERROR_TYPE_INFO,
                     _("Adding blacklisting entry for peer `%s':`%s'\n"),
                     GNUNET_i2s(&peer),
                     pos);
          GST_blacklist_add_peer(&peer, pos);
        }
      GNUNET_free(plugs);
    }
  (*res)++;
}


/**
 * Read blacklist configuration
 *
 * @param cfg the configuration handle
 * @param my_id my peer identity
 */
static void
read_blacklist_configuration(const struct GNUNET_CONFIGURATION_Handle *cfg,
                             const struct GNUNET_PeerIdentity *my_id)
{
  char cfg_sect[512];
  unsigned int res = 0;

  GNUNET_snprintf(cfg_sect,
                  sizeof(cfg_sect),
                  "transport-blacklist-%s",
                  GNUNET_i2s_full(my_id));
  GNUNET_CONFIGURATION_iterate_section_values(cfg,
                                              cfg_sect,
                                              &blacklist_cfg_iter,
                                              &res);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Loaded %u blacklisting entries from configuration\n",
             res);
}


/**
 * Initiate transport service.
 *
 * @param cls closure
 * @param c configuration to use
 * @param service the initialized service
 */
static void
run(void *cls,
    const struct GNUNET_CONFIGURATION_Handle *c,
    struct GNUNET_SERVICE_Handle *service)
{
  char *keyfile;
  struct GNUNET_CRYPTO_EddsaPrivateKey *pk;
  long long unsigned int max_fd_cfg;
  int max_fd_rlimit;
  int max_fd;
  int friend_only;

  /* setup globals */
  GST_cfg = c;
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename(c,
                                                           "PEER",
                                                           "PRIVATE_KEY",
                                                           &keyfile))
    {
      GNUNET_log(
        GNUNET_ERROR_TYPE_ERROR,
        _(
          "Transport service is lacking key configuration settings. Exiting.\n"));
      GNUNET_SCHEDULER_shutdown();
      return;
    }
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_time(c,
                                                       "transport",
                                                       "HELLO_EXPIRATION",
                                                       &hello_expiration))
    {
      hello_expiration = GNUNET_CONSTANTS_HELLO_ADDRESS_EXPIRATION;
    }
  pk = GNUNET_CRYPTO_eddsa_key_create_from_file(keyfile);
  GNUNET_free(keyfile);
  GNUNET_assert(NULL != pk);
  GST_my_private_key = pk;

  GST_stats = GNUNET_STATISTICS_create("transport", GST_cfg);
  GST_peerinfo = GNUNET_PEERINFO_connect(GST_cfg);
  GNUNET_CRYPTO_eddsa_key_get_public(GST_my_private_key,
                                     &GST_my_identity.public_key);
  GNUNET_assert(NULL != GST_my_private_key);

  GNUNET_log(GNUNET_ERROR_TYPE_INFO,
             "My identity is `%s'\n",
             GNUNET_i2s_full(&GST_my_identity));

  GNUNET_SCHEDULER_add_shutdown(&shutdown_task, NULL);
  if (NULL == GST_peerinfo)
    {
      GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
                 _("Could not access PEERINFO service.  Exiting.\n"));
      GNUNET_SCHEDULER_shutdown();
      return;
    }

  max_fd_rlimit = 0;
#if HAVE_GETRLIMIT
  {
    struct rlimit r_file;

    if (0 == getrlimit(RLIMIT_NOFILE, &r_file))
      {
        max_fd_rlimit = r_file.rlim_cur;
        GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
                   "Maximum number of open files was: %u/%u\n",
                   (unsigned int)r_file.rlim_cur,
                   (unsigned int)r_file.rlim_max);
      }
    max_fd_rlimit =
      (9 * max_fd_rlimit) / 10; /* Keep 10% for rest of transport */
  }
#endif
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_number(GST_cfg,
                                                         "transport",
                                                         "MAX_FD",
                                                         &max_fd_cfg))
    max_fd_cfg = max_fd_rlimit;

  if (max_fd_cfg > max_fd_rlimit)
    max_fd = max_fd_cfg;
  else
    max_fd = max_fd_rlimit;
  if (max_fd < DEFAULT_MAX_FDS)
    max_fd = DEFAULT_MAX_FDS;

  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
             "Limiting number of sockets to %u: validation %u, neighbors: %u\n",
             max_fd,
             (max_fd / 3),
             (max_fd / 3) * 2);

  friend_only =
    GNUNET_CONFIGURATION_get_value_yesno(GST_cfg, "topology", "FRIENDS-ONLY");
  if (GNUNET_SYSERR == friend_only)
    friend_only = GNUNET_NO; /* According to topology defaults */
  /* start subsystems */
  /* Disable DSTJ peer */
  {
    struct GNUNET_PeerIdentity dstj;
    const char *ds = "DSTJBRRKZ8TBW3FGK6B0M5QXWT9WYNZ45H5MCV4HY7ST64Q8T9F0";

    GNUNET_assert(
      GNUNET_OK ==
      GNUNET_CRYPTO_eddsa_public_key_from_string(ds,
                                                 strlen(ds),
                                                 &dstj.public_key));
    GST_blacklist_add_peer(&dstj, NULL);
  }
  read_blacklist_configuration(GST_cfg, &GST_my_identity);
  GST_is = GNUNET_NT_scanner_init();
  GST_ats_connect = GNUNET_ATS_connectivity_init(GST_cfg);
  GST_ats =
    GNUNET_ATS_scheduling_init(GST_cfg, &ats_request_address_change, NULL);
  GST_ats_init();
  GST_manipulation_init();
  GST_plugins_load(&GST_manipulation_recv,
                   &plugin_env_address_change_notification,
                   &plugin_env_session_start,
                   &plugin_env_session_end);
  GST_hello_start(friend_only, &process_hello_update, NULL);
  GST_neighbours_start((max_fd / 3) * 2);
  active_stccs = GNUNET_CONTAINER_multipeermap_create(128, GNUNET_YES);
  plugin_nc = GNUNET_notification_context_create(0);
  GST_validation_start((max_fd / 3));
}


/**
 * Define "main" method using service macro.
 */
GNUNET_SERVICE_MAIN(
  "transport",
  GNUNET_SERVICE_OPTION_NONE,
  &run,
  &client_connect_cb,
  &client_disconnect_cb,
  NULL,
  GNUNET_MQ_hd_fixed_size(client_start,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_START,
                          struct StartMessage,
                          NULL),
  GNUNET_MQ_hd_var_size(client_hello,
                        GNUNET_MESSAGE_TYPE_HELLO,
                        struct GNUNET_MessageHeader,
                        NULL),
  GNUNET_MQ_hd_var_size(client_send,
                        GNUNET_MESSAGE_TYPE_TRANSPORT_SEND,
                        struct OutboundMessage,
                        NULL),
  GNUNET_MQ_hd_var_size(client_address_to_string,
                        GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING,
                        struct AddressLookupMessage,
                        NULL),
  GNUNET_MQ_hd_fixed_size(client_monitor_peers,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_REQUEST,
                          struct PeerMonitorMessage,
                          NULL),
  GNUNET_MQ_hd_fixed_size(client_blacklist_init,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_BLACKLIST_INIT,
                          struct GNUNET_MessageHeader,
                          NULL),
  GNUNET_MQ_hd_fixed_size(client_blacklist_reply,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_BLACKLIST_REPLY,
                          struct BlacklistMessage,
                          NULL),
  GNUNET_MQ_hd_fixed_size(client_set_metric,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_TRAFFIC_METRIC,
                          struct TrafficMetricMessage,
                          NULL),
  GNUNET_MQ_hd_fixed_size(client_monitor_plugins,
                          GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PLUGIN_START,
                          struct GNUNET_MessageHeader,
                          NULL),
  GNUNET_MQ_handler_end());


/* end of file gnunet-service-transport.c */