gnunet-communicator-libp2p.c

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/*
     This file is part of GNUnet
     Copyright (C) 2025 GNUnet e.V.
 
     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.
 
     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Affero General Public License for more details.
 
     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
     SPDX-License-Identifier: AGPL3.0-or-later
 */
 
#include "platform.h"
#include "gnunet_common.h"
#include "gnunet_util_lib.h"
#include "gnunet_pils_service.h"
#include "gnunet_core_service.h"
#include "gnunet_peerstore_service.h"
#include "gnunet_protocols.h"
#include "gnunet_signatures.h"
#include "gnunet_constants.h"
#include "gnunet_nat_service.h"
#include "gnunet_statistics_service.h"
#include "gnunet_transport_communication_service.h"
#include "gnunet_resolver_service.h"
 
#include <libp2p/basic/scheduler.hpp>
#include <libp2p/common/literals.hpp>
#include <libp2p/injector/host_injector.hpp>
#include <libp2p/layer/websocket/ws_adaptor.hpp>
#include <libp2p/log/configurator.hpp>
#include <libp2p/log/logger.hpp>
#include <libp2p/protocol/echo.hpp>
 
 
/* Shorthand for Logging */
#define LOG(kind, ...) GNUNET_log_from (kind, "communicator-tcp", __VA_ARGS__)
 
 
GNUNET_NETWORK_STRUCT_BEGIN
 
 
struct Queue
{
  struct GNUNET_PeerIdentity target;
 
  struct GNUNET_SCHEDULER_Task *read_task;
 
  struct GNUNET_SCHEDULER_Task *write_task;
 
  struct sockaddr *address;
 
};
 
 
struct Addresses
{
  struct Addresses *next;
 
  struct Addresses *prev;
 
  struct sockaddr *addr;
 
  socklen_t addr_len;
 
};
 
 
static struct GNUNET_PILS_Handle *pils;
 
static struct GNUNET_STATISTICS_Handle *stats;
 
static struct GNUNET_TRANSPORT_CommunicatorHandle *ch;
 
static struct GNUNET_CONTAINER_MultiHashMap *queue_map;
 
static struct GNUNET_CONTAINER_MultiHashMap *lt_map;
 
static struct GNUNET_PeerIdentity my_identity;
 
static struct GNUNET_CRYPTO_EddsaPrivateKey *my_private_key;
 
static struct GNUNET_CRYPTO_EcdhePrivateKey my_x25519_private_key;
 
static const struct GNUNET_CONFIGURATION_Handle *cfg;
 
static struct Addresses *addrs_head;
 
static struct Addresses *addrs_tail;
 
static struct GNUNET_PEERSTORE_Handle *peerstore;
 
static int shutdown_running = GNUNET_NO;
 
static void
listen_cb (void *cls);
 
static void
eddsa_priv_to_hpke_key (struct GNUNET_CRYPTO_EddsaPrivateKey *edpk,
                        struct GNUNET_CRYPTO_EcdhePrivateKey *pk)
{
  struct GNUNET_CRYPTO_BlindablePrivateKey key;
  key.type = htonl (GNUNET_PUBLIC_KEY_TYPE_EDDSA);
  key.eddsa_key = *edpk;
  GNUNET_CRYPTO_hpke_sk_to_x25519 (&key, pk);
}
 
 
static void
eddsa_pub_to_hpke_key (struct GNUNET_CRYPTO_EddsaPublicKey *edpk,
                       struct GNUNET_CRYPTO_EcdhePublicKey *pk)
{
  struct GNUNET_CRYPTO_BlindablePublicKey key;
  key.type = htonl (GNUNET_PUBLIC_KEY_TYPE_EDDSA);
  key.eddsa_key = *edpk;
  GNUNET_CRYPTO_hpke_pk_to_x25519 (&key, pk);
}
 
 
static void
queue_destroy (struct Queue *queue)
{
  struct ListenTask *lt = NULL;
  struct GNUNET_HashCode h_sock;
  int sockfd;
 
  if (NULL != queue->listen_sock)
  {
    sockfd = GNUNET_NETWORK_get_fd (queue->listen_sock);
    GNUNET_CRYPTO_hash (&sockfd,
                        sizeof(int),
                        &h_sock);
 
    lt = GNUNET_CONTAINER_multihashmap_get (lt_map, &h_sock);
  }
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Disconnecting queue for peer `%s'\n",
              GNUNET_i2s (&queue->target));
  if (NULL != queue->rekey_monotime_sc)
  {
    GNUNET_PEERSTORE_store_cancel (queue->rekey_monotime_sc);
    queue->rekey_monotime_sc = NULL;
  }
  if (NULL != queue->handshake_monotime_sc)
  {
    GNUNET_PEERSTORE_store_cancel (queue->handshake_monotime_sc);
    queue->handshake_monotime_sc = NULL;
  }
  if (NULL != queue->handshake_ack_monotime_sc)
  {
    GNUNET_PEERSTORE_store_cancel (queue->handshake_ack_monotime_sc);
    queue->handshake_ack_monotime_sc = NULL;
  }
  if (NULL != queue->rekey_monotime_get)
  {
    GNUNET_PEERSTORE_iteration_stop (queue->rekey_monotime_get);
    queue->rekey_monotime_get = NULL;
  }
  if (NULL != queue->handshake_monotime_get)
  {
    GNUNET_PEERSTORE_iteration_stop (queue->handshake_monotime_get);
    queue->handshake_monotime_get = NULL;
  }
  if (NULL != queue->handshake_ack_monotime_get)
  {
    GNUNET_PEERSTORE_iteration_stop (queue->handshake_ack_monotime_get);
    queue->handshake_ack_monotime_get = NULL;
  }
  if (NULL != queue->qh)
  {
    GNUNET_TRANSPORT_communicator_mq_del (queue->qh);
    queue->qh = NULL;
  }
  GNUNET_assert (
    GNUNET_YES ==
    GNUNET_CONTAINER_multihashmap_remove (queue_map, &queue->key, queue));
  GNUNET_STATISTICS_set (stats,
                         "# queues active",
                         GNUNET_CONTAINER_multihashmap_size (queue_map),
                         GNUNET_NO);
  if (NULL != queue->read_task)
  {
    GNUNET_SCHEDULER_cancel (queue->read_task);
    queue->read_task = NULL;
  }
  if (NULL != queue->write_task)
  {
    GNUNET_SCHEDULER_cancel (queue->write_task);
    queue->write_task = NULL;
  }
  if (GNUNET_SYSERR == GNUNET_NETWORK_socket_close (queue->sock))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "closing socket failed\n");
  }
  gcry_cipher_close (queue->in_cipher);
  gcry_cipher_close (queue->out_cipher);
  GNUNET_free (queue->address);
  if (0 != queue->backpressure)
    queue->destroyed = GNUNET_YES;
  else
    GNUNET_free (queue);
 
  if (NULL == lt)
    return;
 
  if ((! shutdown_running) && (NULL == lt->listen_task))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "add read net listen\n");
    lt->listen_task = GNUNET_SCHEDULER_add_read_net (
      GNUNET_TIME_UNIT_FOREVER_REL,
      lt->listen_sock,
      &listen_cb,
      lt);
  }
  else
    GNUNET_free (lt);
}
 
 
static void
calculate_hmac (struct GNUNET_HashCode *hmac_secret,
                const void *buf,
                size_t buf_size,
                struct GNUNET_ShortHashCode *smac)
{
  struct GNUNET_HashCode mac;
 
  GNUNET_CRYPTO_hmac_raw (hmac_secret,
                          sizeof(struct GNUNET_HashCode),
                          buf,
                          buf_size,
                          &mac);
  /* truncate to `struct GNUNET_ShortHashCode` */
  memcpy (smac, &mac, sizeof(struct GNUNET_ShortHashCode));
  /* ratchet hmac key */
  GNUNET_CRYPTO_hash (hmac_secret,
                      sizeof(struct GNUNET_HashCode),
                      hmac_secret);
}
 
 
static void
queue_finish (struct Queue *queue)
{
  struct TCPFinish fin;
 
  memset (&fin, 0, sizeof(fin));
  fin.header.size = htons (sizeof(fin));
  fin.header.type = htons (GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_FINISH);
  calculate_hmac (&queue->out_hmac, &fin, sizeof(fin), &fin.hmac);
  /* if there is any message left in pwrite_buf, we
     overwrite it (possibly dropping the last message
     from CORE hard here) */
  memcpy (queue->pwrite_buf, &fin, sizeof(fin));
  queue->pwrite_off = sizeof(fin);
  /* This flag will ensure that #queue_write() no longer
     notifies CORE about the possibility of sending
     more data, and that #queue_write() will call
  #queue_destroy() once the @c fin was fully written. */
  queue->finishing = GNUNET_YES;
}
 
 
static void
queue_read (void *cls);
 
 
static void
core_read_finished_cb (void *cls, int success)
{
  struct Queue *queue = cls;
  if (GNUNET_OK != success)
    GNUNET_STATISTICS_update (stats,
                              "# messages lost in communicator API towards CORE",
                              1,
                              GNUNET_NO);
  if (NULL == queue)
    return;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "backpressure %u\n",
              queue->backpressure);
 
  queue->backpressure--;
  /* handle deferred queue destruction */
  if ((queue->destroyed) && (0 == queue->backpressure))
  {
    GNUNET_free (queue);
    return;
  }
  else if (GNUNET_YES != queue->destroyed)
  {
    queue->timeout =
      GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT
                                        );
    /* possibly unchoke reading, now that CORE made progress */
    if (NULL == queue->read_task)
      queue->read_task =
        GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_absolute_get_remaining (
                                         queue->timeout),
                                       queue->sock,
                                       &queue_read,
                                       queue);
  }
}
 
 
static void
pass_plaintext_to_core (struct Queue *queue,
                        const void *plaintext,
                        size_t plaintext_len)
{
  const struct GNUNET_MessageHeader *hdr = plaintext;
  int ret;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "pass message from %s to core\n",
              GNUNET_i2s (&queue->target));
 
  if (ntohs (hdr->size) != plaintext_len)
  {
    /* NOTE: If we ever allow multiple CORE messages in one
       BOX, this will have to change! */
    GNUNET_break (0);
    return;
  }
  ret = GNUNET_TRANSPORT_communicator_receive (ch,
                                               &queue->target,
                                               hdr,
                                               ADDRESS_VALIDITY_PERIOD,
                                               &core_read_finished_cb,
                                               queue);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "passed to core\n");
  if (GNUNET_OK == ret)
    queue->backpressure++;
  GNUNET_break (GNUNET_NO != ret);  /* backpressure not working!? */
  if (GNUNET_SYSERR == ret)
    GNUNET_STATISTICS_update (stats,
                              "# bytes lost due to CORE not running",
                              plaintext_len,
                              GNUNET_NO);
}
 
 
static void
setup_cipher (const struct GNUNET_ShortHashCode *prk,
              const struct GNUNET_PeerIdentity *pid,
              gcry_cipher_hd_t *cipher,
              struct GNUNET_HashCode *hmac_key)
{
  char key[256 / 8];
  char ctr[128 / 8];
 
  GNUNET_assert (0 == gcry_cipher_open (cipher,
                                        GCRY_CIPHER_AES256 /* low level: go for speed */
                                        ,
                                        GCRY_CIPHER_MODE_CTR,
                                        0 /* flags */));
  GNUNET_assert (GNUNET_YES ==
                 GNUNET_CRYPTO_hkdf_expand (key,
                                            sizeof(key),
                                            prk,
                                            "gnunet-communicator-tcp-key",
                                            strlen (
                                              "gnunet-communicator-tcp-key"),
                                            NULL,
                                            0));
  GNUNET_assert (0 == gcry_cipher_setkey (*cipher, key, sizeof(key)));
  GNUNET_assert (GNUNET_YES ==
                 GNUNET_CRYPTO_hkdf_expand (ctr,
                                            sizeof(ctr),
                                            prk,
                                            "gnunet-communicator-tcp-ctr",
                                            strlen (
                                              "gnunet-communicator-tcp-ctr"),
                                            NULL,
                                            0));
  gcry_cipher_setctr (*cipher, ctr, sizeof(ctr));
  GNUNET_assert (GNUNET_YES ==
                 GNUNET_CRYPTO_hkdf_expand (hmac_key,
                                            sizeof(struct GNUNET_HashCode),
                                            prk,
                                            "gnunet-communicator-hmac",
                                            strlen ("gnunet-communicator-hmac"),
                                            NULL,
                                            0));
}
 
 
static void
rekey_monotime_store_cb (void *cls, int success)
{
  struct Queue *queue = cls;
  if (GNUNET_OK != success)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to store rekey monotonic time in PEERSTORE!\n");
  }
  queue->rekey_monotime_sc = NULL;
  GNUNET_PEERSTORE_iteration_next (queue->rekey_monotime_get, 1);
}
 
 
static void
rekey_monotime_cb (void *cls,
                   const struct GNUNET_PEERSTORE_Record *record,
                   const char *emsg)
{
  struct Queue *queue = cls;
  struct GNUNET_TIME_AbsoluteNBO *mtbe;
  struct GNUNET_TIME_Absolute mt;
  const struct GNUNET_PeerIdentity *pid;
  struct GNUNET_TIME_AbsoluteNBO *rekey_monotonic_time;
 
  (void) emsg;
 
  rekey_monotonic_time = &queue->rekey_monotonic_time;
  pid = &queue->target;
  if (NULL == record)
  {
    queue->rekey_monotime_get = NULL;
    return;
  }
  if (sizeof(*mtbe) != record->value_size)
  {
    GNUNET_PEERSTORE_iteration_next (queue->rekey_monotime_get, 1);
    GNUNET_break (0);
    return;
  }
  mtbe = record->value;
  mt = GNUNET_TIME_absolute_ntoh (*mtbe);
  if (mt.abs_value_us > GNUNET_TIME_absolute_ntoh (
        queue->rekey_monotonic_time).abs_value_us)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Queue from %s dropped, rekey monotime in the past\n",
                GNUNET_i2s (&queue->target));
    GNUNET_break (0);
    GNUNET_PEERSTORE_iteration_stop (queue->rekey_monotime_get);
    queue->rekey_monotime_get = NULL;
    // FIXME: Why should we try to gracefully finish here??
    queue_finish (queue);
    return;
  }
  queue->rekey_monotime_sc = GNUNET_PEERSTORE_store (peerstore,
                                                     "transport_tcp_communicator",
                                                     pid,
                                                     GNUNET_PEERSTORE_TRANSPORT_TCP_COMMUNICATOR_REKEY,
                                                     rekey_monotonic_time,
                                                     sizeof(*
                                                            rekey_monotonic_time),
                                                     GNUNET_TIME_UNIT_FOREVER_ABS,
                                                     GNUNET_PEERSTORE_STOREOPTION_REPLACE,
                                                     &rekey_monotime_store_cb,
                                                     queue);
}
 
 
static void
setup_in_cipher_elligator (
  const struct GNUNET_CRYPTO_HpkeEncapsulation *c,
  struct Queue *queue)
{
  struct GNUNET_ShortHashCode k;
 
  GNUNET_CRYPTO_hpke_elligator_kem_decaps (&my_x25519_private_key, c, &k);
  setup_cipher (&k, &my_identity, &queue->in_cipher, &queue->in_hmac);
}
 
 
static void
setup_in_cipher (const struct GNUNET_CRYPTO_HpkeEncapsulation *ephemeral,
                 struct Queue *queue)
{
  struct GNUNET_ShortHashCode k;
 
  GNUNET_CRYPTO_eddsa_kem_decaps (my_private_key, ephemeral, &k);
  setup_cipher (&k, &my_identity, &queue->in_cipher, &queue->in_hmac);
}
 
 
static void
do_rekey (struct Queue *queue, const struct TCPRekey *rekey)
{
  struct TcpRekeySignature thp;
 
  thp.purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_REKEY);
  thp.purpose.size = htonl (sizeof(thp));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "do_rekey size %u\n",
              thp.purpose.size);
  thp.sender = queue->target;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "sender %s\n",
              GNUNET_p2s (&thp.sender.public_key));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "sender %s\n",
              GNUNET_p2s (&queue->target.public_key));
  thp.receiver = my_identity;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "receiver %s\n",
              GNUNET_p2s (&thp.receiver.public_key));
  thp.ephemeral = rekey->ephemeral;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "ephemeral %s\n",
              GNUNET_e2s ((struct GNUNET_CRYPTO_EcdhePublicKey*) &thp.ephemeral)
              );
  thp.monotonic_time = rekey->monotonic_time;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "time %s\n",
              GNUNET_STRINGS_absolute_time_to_string (
                GNUNET_TIME_absolute_ntoh (thp.monotonic_time)));
  GNUNET_assert (ntohl ((&thp)->purpose.size) == sizeof (*(&thp)));
  if (GNUNET_OK !=
      GNUNET_CRYPTO_eddsa_verify (
        GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_REKEY,
        &thp,
        &rekey->sender_sig,
        &queue->target.public_key))
  {
    GNUNET_break (0);
    // FIXME Why should we try to gracefully finish here?
    queue_finish (queue);
    return;
  }
  queue->rekey_monotonic_time = rekey->monotonic_time;
  queue->rekey_monotime_get = GNUNET_PEERSTORE_iteration_start (peerstore,
                                                                "transport_tcp_communicator",
                                                                &queue->target,
                                                                GNUNET_PEERSTORE_TRANSPORT_TCP_COMMUNICATOR_REKEY,
                                                                &
                                                                rekey_monotime_cb,
                                                                queue);
  gcry_cipher_close (queue->in_cipher);
  queue->rekeyed = GNUNET_YES;
  setup_in_cipher (&rekey->ephemeral, queue);
}
 
 
static void
handshake_ack_monotime_store_cb (void *cls, int success)
{
  struct Queue *queue = cls;
 
  if (GNUNET_OK != success)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to store handshake ack monotonic time in PEERSTORE!\n");
  }
  queue->handshake_ack_monotime_sc = NULL;
  GNUNET_PEERSTORE_iteration_next (queue->handshake_ack_monotime_get, 1);
}
 
 
static void
handshake_ack_monotime_cb (void *cls,
                           const struct GNUNET_PEERSTORE_Record *record,
                           const char *emsg)
{
  struct Queue *queue = cls;
  struct GNUNET_TIME_AbsoluteNBO *mtbe;
  struct GNUNET_TIME_Absolute mt;
  const struct GNUNET_PeerIdentity *pid;
  struct GNUNET_TIME_AbsoluteNBO *handshake_ack_monotonic_time;
 
  (void) emsg;
 
  handshake_ack_monotonic_time = &queue->handshake_ack_monotonic_time;
  pid = &queue->target;
  if (NULL == record)
  {
    queue->handshake_ack_monotime_get = NULL;
    return;
  }
  if (sizeof(*mtbe) != record->value_size)
  {
    GNUNET_PEERSTORE_iteration_next (queue->handshake_ack_monotime_get, 1);
    GNUNET_break (0);
    return;
  }
  mtbe = record->value;
  mt = GNUNET_TIME_absolute_ntoh (*mtbe);
  if (mt.abs_value_us > GNUNET_TIME_absolute_ntoh (
        queue->handshake_ack_monotonic_time).abs_value_us)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Queue from %s dropped, handshake ack monotime in the past\n",
                GNUNET_i2s (&queue->target));
    GNUNET_break (0);
    GNUNET_PEERSTORE_iteration_stop (queue->handshake_ack_monotime_get);
    queue->handshake_ack_monotime_get = NULL;
    // FIXME: Why should we try to gracefully finish here?
    queue_finish (queue);
    return;
  }
  queue->handshake_ack_monotime_sc =
    GNUNET_PEERSTORE_store (peerstore,
                            "transport_tcp_communicator",
                            pid,
                            GNUNET_PEERSTORE_TRANSPORT_TCP_COMMUNICATOR_HANDSHAKE_ACK,
                            handshake_ack_monotonic_time,
                            sizeof(*handshake_ack_monotonic_time),
                            GNUNET_TIME_UNIT_FOREVER_ABS,
                            GNUNET_PEERSTORE_STOREOPTION_REPLACE,
                            &handshake_ack_monotime_store_cb,
                            queue);
}
 
 
static void
send_challenge (struct GNUNET_CRYPTO_ChallengeNonceP challenge,
                struct Queue *queue)
{
  struct TCPConfirmationAck tca;
  struct TcpHandshakeAckSignature thas;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "sending challenge\n");
 
  tca.header.type = ntohs (
    GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_CONFIRMATION_ACK);
  tca.header.size = ntohs (sizeof(tca));
  tca.challenge = challenge;
  tca.sender = my_identity;
  tca.monotonic_time =
    GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get_monotonic (cfg));
  thas.purpose.purpose = htonl (
    GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_HANDSHAKE_ACK);
  thas.purpose.size = htonl (sizeof(thas));
  thas.sender = my_identity;
  thas.receiver = queue->target;
  thas.monotonic_time = tca.monotonic_time;
  thas.challenge = tca.challenge;
  GNUNET_CRYPTO_eddsa_sign (my_private_key,
                            &thas,
                            &tca.sender_sig);
  GNUNET_assert (0 ==
                 gcry_cipher_encrypt (queue->out_cipher,
                                      &queue->cwrite_buf[queue->cwrite_off],
                                      sizeof(tca),
                                      &tca,
                                      sizeof(tca)));
  queue->cwrite_off += sizeof(tca);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "sending challenge done\n");
}
 
 
static void
setup_out_cipher (struct Queue *queue, struct GNUNET_ShortHashCode *dh)
{
  setup_cipher (dh, &queue->target, &queue->out_cipher, &queue->out_hmac);
  queue->rekey_time = GNUNET_TIME_relative_to_absolute (rekey_interval);
  queue->rekey_left_bytes =
    GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK, rekey_max_bytes);
}
 
 
static void
inject_rekey (struct Queue *queue)
{
  struct TCPRekey rekey;
  struct TcpRekeySignature thp;
  struct GNUNET_ShortHashCode k;
 
  GNUNET_assert (0 == queue->pwrite_off);
  memset (&rekey, 0, sizeof(rekey));
  GNUNET_CRYPTO_eddsa_kem_encaps (&queue->target.public_key, &rekey.ephemeral,
                                  &k);
  rekey.header.type = ntohs (GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_REKEY);
  rekey.header.size = ntohs (sizeof(rekey));
  rekey.monotonic_time =
    GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get_monotonic (cfg));
  thp.purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_REKEY);
  thp.purpose.size = htonl (sizeof(thp));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "inject_rekey size %u\n",
              thp.purpose.size);
  thp.sender = my_identity;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "sender %s\n",
              GNUNET_p2s (&thp.sender.public_key));
  thp.receiver = queue->target;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "receiver %s\n",
              GNUNET_p2s (&thp.receiver.public_key));
  thp.ephemeral = rekey.ephemeral;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "ephemeral %s\n",
              GNUNET_e2s ((struct GNUNET_CRYPTO_EcdhePublicKey*) &thp.ephemeral)
              );
  thp.monotonic_time = rekey.monotonic_time;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "time %s\n",
              GNUNET_STRINGS_absolute_time_to_string (
                GNUNET_TIME_absolute_ntoh (thp.monotonic_time)));
  GNUNET_CRYPTO_eddsa_sign (my_private_key,
                            &thp,
                            &rekey.sender_sig);
  calculate_hmac (&queue->out_hmac, &rekey, sizeof(rekey), &rekey.hmac);
  /* Encrypt rekey message with 'old' cipher */
  GNUNET_assert (0 ==
                 gcry_cipher_encrypt (queue->out_cipher,
                                      &queue->cwrite_buf[queue->cwrite_off],
                                      sizeof(rekey),
                                      &rekey,
                                      sizeof(rekey)));
  queue->cwrite_off += sizeof(rekey);
  /* Setup new cipher for successive messages */
  gcry_cipher_close (queue->out_cipher);
  setup_out_cipher (queue, &k);
}
 
 
static int
pending_reversals_delete_it (void *cls,
                             const struct GNUNET_HashCode *key,
                             void *value)
{
  struct PendingReversal *pending_reversal = value;
  (void) cls;
 
  if (NULL != pending_reversal->timeout_task)
  {
    GNUNET_SCHEDULER_cancel (pending_reversal->timeout_task);
    pending_reversal->timeout_task = NULL;
  }
  GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (
                   pending_reversals,
                   key,
                   pending_reversal));
  GNUNET_free (pending_reversal->in);
  GNUNET_free (pending_reversal);
  return GNUNET_OK;
}
 
 
static void
check_and_remove_pending_reversal (struct sockaddr *in, sa_family_t sa_family,
                                   struct GNUNET_PeerIdentity *sender)
{
  if (AF_INET == sa_family)
  {
    struct PendingReversal *pending_reversal;
    struct GNUNET_HashCode key;
    struct sockaddr_in *natted_address;
 
    natted_address = GNUNET_memdup (in, sizeof (struct sockaddr));
    natted_address->sin_port = 0;
    GNUNET_CRYPTO_hash (natted_address,
                        sizeof(struct sockaddr),
                        &key);
 
    pending_reversal = GNUNET_CONTAINER_multihashmap_get (pending_reversals,
                                                          &key);
    if (NULL != pending_reversal && (NULL == sender ||
                                     0 != memcmp (sender,
                                                  &pending_reversal->target,
                                                  sizeof(struct
                                                         GNUNET_PeerIdentity))))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "Removing invalid pending reversal for `%s'at `%s'\n",
                  GNUNET_i2s (&pending_reversal->target),
                  GNUNET_a2s (in, sizeof (struct sockaddr)));
      pending_reversals_delete_it (NULL, &key, pending_reversal);
    }
    GNUNET_free (natted_address);
  }
}
 
 
static void
free_proto_queue (struct ProtoQueue *pq)
{
  if (NULL != pq->listen_sock)
  {
    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (pq->listen_sock));
    pq->listen_sock = NULL;
  }
  if (NULL != pq->read_task)
  {
    GNUNET_SCHEDULER_cancel (pq->read_task);
    pq->read_task = NULL;
  }
  if (NULL != pq->write_task)
  {
    GNUNET_SCHEDULER_cancel (pq->write_task);
    pq->write_task = NULL;
  }
  check_and_remove_pending_reversal (pq->address, pq->address->sa_family, NULL);
  GNUNET_NETWORK_socket_close (pq->sock);
  GNUNET_free (pq->address);
  GNUNET_CONTAINER_DLL_remove (proto_head, proto_tail, pq);
  GNUNET_free (pq);
}
 
 
static void
proto_queue_write (void *cls)
{
  struct ProtoQueue *pq = cls;
  ssize_t sent;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "In proto queue write\n");
  pq->write_task = NULL;
  if (0 != pq->write_off)
  {
    sent = GNUNET_NETWORK_socket_send (pq->sock,
                                       pq->write_buf,
                                       pq->write_off);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Sent %lu bytes to TCP queue\n", sent);
    if ((-1 == sent) && (EAGAIN != errno) && (EINTR != errno))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "send");
      free_proto_queue (pq);
      return;
    }
    if (sent > 0)
    {
      size_t usent = (size_t) sent;
      pq->write_off -= usent;
      memmove (pq->write_buf,
               &pq->write_buf[usent],
               pq->write_off);
    }
  }
  /* do we care to write more? */
  if ((0 < pq->write_off))
    pq->write_task =
      GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                      pq->sock,
                                      &proto_queue_write,
                                      pq);
}
 
 
static void
queue_write (void *cls)
{
  struct Queue *queue = cls;
  ssize_t sent;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "In queue write\n");
  queue->write_task = NULL;
  if (0 != queue->cwrite_off)
  {
    sent = GNUNET_NETWORK_socket_send (queue->sock,
                                       queue->cwrite_buf,
                                       queue->cwrite_off);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Sent %lu bytes to TCP queue\n", sent);
    if ((-1 == sent) && (EAGAIN != errno) && (EINTR != errno))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "send");
      queue_destroy (queue);
      return;
    }
    if (sent > 0)
    {
      size_t usent = (size_t) sent;
      queue->cwrite_off -= usent;
      memmove (queue->cwrite_buf,
               &queue->cwrite_buf[usent],
               queue->cwrite_off);
      queue->timeout =
        GNUNET_TIME_relative_to_absolute (
          GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT);
    }
  }
  {
    /* can we encrypt more? (always encrypt full messages, needed
       such that #mq_cancel() can work!) */
    unsigned int we_do_not_need_to_rekey = (0 < queue->rekey_left_bytes
                                            - (queue->cwrite_off
                                               + queue->pwrite_off
                                               + sizeof (struct TCPRekey)));
    if (we_do_not_need_to_rekey &&
        (queue->pwrite_off > 0) &&
        (queue->cwrite_off + queue->pwrite_off <= BUF_SIZE))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "Encrypting %lu bytes\n", queue->pwrite_off);
      GNUNET_assert (0 ==
                     gcry_cipher_encrypt (queue->out_cipher,
                                          &queue->cwrite_buf[queue->cwrite_off],
                                          queue->pwrite_off,
                                          queue->pwrite_buf,
                                          queue->pwrite_off));
      if (queue->rekey_left_bytes > queue->pwrite_off)
        queue->rekey_left_bytes -= queue->pwrite_off;
      else
        queue->rekey_left_bytes = 0;
      queue->cwrite_off += queue->pwrite_off;
      queue->pwrite_off = 0;
    }
    // if ((-1 != unverified_size)&& ((0 == queue->pwrite_off) &&
    if (((0 == queue->rekey_left_bytes) ||
         (0 == GNUNET_TIME_absolute_get_remaining (
            queue->rekey_time).rel_value_us)) &&
        (((0 == queue->pwrite_off) || ! we_do_not_need_to_rekey) &&
         (queue->cwrite_off + sizeof (struct TCPRekey) <= BUF_SIZE)))
    {
      inject_rekey (queue);
    }
  }
  if ((0 == queue->pwrite_off) && (! queue->finishing) &&
      (GNUNET_YES == queue->mq_awaits_continue))
  {
    queue->mq_awaits_continue = GNUNET_NO;
    GNUNET_MQ_impl_send_continue (queue->mq);
  }
  /* did we just finish writing 'finish'? */
  if ((0 == queue->cwrite_off) && (GNUNET_YES == queue->finishing))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Finishing queue\n");
    queue_destroy (queue);
    return;
  }
  /* do we care to write more? */
  if ((0 < queue->cwrite_off) || (0 < queue->pwrite_off))
    queue->write_task =
      GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                      queue->sock,
                                      &queue_write,
                                      queue);
}
 
 
static size_t
try_handle_plaintext (struct Queue *queue)
{
  const struct GNUNET_MessageHeader *hdr;
  const struct TCPConfirmationAck *tca;
  const struct TCPBox *box;
  const struct TCPRekey *rekey;
  const struct TCPFinish *fin;
  struct TCPRekey rekeyz;
  struct TCPFinish finz;
  struct GNUNET_ShortHashCode tmac;
  uint16_t type;
  size_t size = 0;
  struct TcpHandshakeAckSignature thas;
  const struct GNUNET_CRYPTO_ChallengeNonceP challenge = queue->challenge;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "try handle plaintext!\n");
 
  hdr = (const struct GNUNET_MessageHeader *) queue->pread_buf;
  if ((sizeof(*hdr) > queue->pread_off))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Handling plaintext, not even a header!\n");
    return 0; /* not even a header */
  }
 
  if ((GNUNET_YES != queue->initial_core_kx_done) && (queue->unverified_size >
                                                      INITIAL_CORE_KX_SIZE))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Already received data of size %lu bigger than KX size %lu!\n",
                queue->unverified_size,
                INITIAL_CORE_KX_SIZE);
    GNUNET_break_op (0);
    queue_finish (queue);
    return 0;
  }
 
  type = ntohs (hdr->type);
  switch (type)
  {
  case GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_CONFIRMATION_ACK:
    tca = (const struct TCPConfirmationAck *) queue->pread_buf;
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "start processing ack\n");
    if (sizeof(*tca) > queue->pread_off)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "Handling plaintext size of tca greater than pread offset.\n")
      ;
      return 0;
    }
    if (ntohs (hdr->size) != sizeof(*tca))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "Handling plaintext size does not match message type.\n");
      GNUNET_break_op (0);
      queue_finish (queue);
      return 0;
    }
 
    thas.purpose.purpose = htonl (
      GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_HANDSHAKE_ACK);
    thas.purpose.size = htonl (sizeof(thas));
    thas.sender = tca->sender;
    thas.receiver = my_identity;
    thas.monotonic_time = tca->monotonic_time;
    thas.challenge = tca->challenge;
 
    if (GNUNET_SYSERR == GNUNET_CRYPTO_eddsa_verify (
          GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_HANDSHAKE_ACK,
          &thas,
          &tca->sender_sig,
          &tca->sender.public_key))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Verification of signature failed!\n");
      GNUNET_break (0);
      queue_finish (queue);
      return 0;
    }
    if (0 != GNUNET_memcmp (&tca->challenge, &challenge))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Challenge in TCPConfirmationAck not correct!\n");
      GNUNET_break (0);
      queue_finish (queue);
      return 0;
    }
 
    queue->handshake_ack_monotime_get = GNUNET_PEERSTORE_iteration_start (
      peerstore,
      "transport_tcp_communicator",
      &queue->target,
      GNUNET_PEERSTORE_TRANSPORT_TCP_COMMUNICATOR_HANDSHAKE_ACK,
      &handshake_ack_monotime_cb,
      queue);
 
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Handling plaintext, ack processed!\n");
 
    if (GNUNET_TRANSPORT_CS_INBOUND ==     queue->cs)
    {
      send_challenge (queue->challenge_received, queue);
      queue->write_task =
        GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                        queue->sock,
                                        &queue_write,
                                        queue);
    }
    else if (GNUNET_TRANSPORT_CS_OUTBOUND ==     queue->cs)
    {
      check_and_remove_pending_reversal (queue->address,
                                         queue->address->sa_family, NULL);
    }
 
    queue->initial_core_kx_done = GNUNET_YES;
 
    {
      char *foreign_addr;
 
      switch (queue->address->sa_family)
      {
      case AF_INET:
        GNUNET_asprintf (&foreign_addr,
                         "%s-%s",
                         COMMUNICATOR_ADDRESS_PREFIX,
                         GNUNET_a2s (queue->address, queue->address_len));
        break;
 
      case AF_INET6:
        GNUNET_asprintf (&foreign_addr,
                         "%s-%s",
                         COMMUNICATOR_ADDRESS_PREFIX,
                         GNUNET_a2s (queue->address, queue->address_len));
        break;
 
      default:
        GNUNET_assert (0);
      }
      queue->qh = GNUNET_TRANSPORT_communicator_mq_add (ch,
                                                        &queue->target,
                                                        foreign_addr,
                                                        UINT16_MAX, /* no MTU */
                                                        GNUNET_TRANSPORT_QUEUE_LENGTH_UNLIMITED,
                                                        0, /* Priority */
                                                        queue->nt,
                                                        queue->cs,
                                                        queue->mq);
 
      GNUNET_free (foreign_addr);
    }
 
    size = ntohs (hdr->size);
    break;
  case GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_BOX:
    /* Special case: header size excludes box itself! */
    box = (const struct TCPBox *) queue->pread_buf;
    if (ntohs (hdr->size) + sizeof(struct TCPBox) > queue->pread_off)
      return 0;
    calculate_hmac (&queue->in_hmac, &box[1], ntohs (hdr->size), &tmac);
    if (0 != memcmp (&tmac, &box->hmac, sizeof(tmac)))
    {
      GNUNET_break_op (0);
      queue_finish (queue);
      return 0;
    }
    pass_plaintext_to_core (queue, (const void *) &box[1], ntohs (hdr->size));
    size = ntohs (hdr->size) + sizeof(*box);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Handling plaintext, box processed!\n");
    GNUNET_STATISTICS_update (stats,
                              "# bytes decrypted with BOX",
                              size,
                              GNUNET_NO);
    GNUNET_STATISTICS_update (stats,
                              "# messages decrypted with BOX",
                              1,
                              GNUNET_NO);
    break;
 
  case GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_REKEY:
    rekey = (const struct TCPRekey *) queue->pread_buf;
    if (sizeof(*rekey) > queue->pread_off)
      return 0;
    if (ntohs (hdr->size) != sizeof(*rekey))
    {
      GNUNET_break_op (0);
      queue_finish (queue);
      return 0;
    }
    rekeyz = *rekey;
    memset (&rekeyz.hmac, 0, sizeof(rekeyz.hmac));
    calculate_hmac (&queue->in_hmac, &rekeyz, sizeof(rekeyz), &tmac);
    if (0 != memcmp (&tmac, &rekey->hmac, sizeof(tmac)))
    {
      GNUNET_break_op (0);
      queue_finish (queue);
      return 0;
    }
    do_rekey (queue, rekey);
    size = ntohs (hdr->size);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Handling plaintext, rekey processed!\n");
    GNUNET_STATISTICS_update (stats,
                              "# rekeying successful",
                              1,
                              GNUNET_NO);
    break;
 
  case GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_FINISH:
    fin = (const struct TCPFinish *) queue->pread_buf;
    if (sizeof(*fin) > queue->pread_off)
      return 0;
    if (ntohs (hdr->size) != sizeof(*fin))
    {
      GNUNET_break_op (0);
      queue_finish (queue);
      return 0;
    }
    finz = *fin;
    memset (&finz.hmac, 0, sizeof(finz.hmac));
    calculate_hmac (&queue->in_hmac, &finz, sizeof(finz), &tmac);
    if (0 != memcmp (&tmac, &fin->hmac, sizeof(tmac)))
    {
      GNUNET_break_op (0);
      queue_finish (queue);
      return 0;
    }
    /* handle FINISH by destroying queue */
    queue_destroy (queue);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Handling plaintext, finish processed!\n");
    break;
 
  default:
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Handling plaintext, nothing processed!\n");
    GNUNET_break_op (0);
    queue_finish (queue);
    return 0;
  }
  GNUNET_assert (0 != size);
  if (-1 != queue->unverified_size)
    queue->unverified_size += size;
  return size;
}
 
 
static void
queue_read (void *cls)
{
  struct Queue *queue = cls;
  struct GNUNET_TIME_Relative left;
  ssize_t rcvd;
 
  queue->read_task = NULL;
  rcvd = GNUNET_NETWORK_socket_recv (queue->sock,
                                     &queue->cread_buf[queue->cread_off],
                                     BUF_SIZE - queue->cread_off);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Received %zd bytes from TCP queue\n", rcvd);
  if (-1 == rcvd)
  {
    if ((EAGAIN != errno) && (EINTR != errno))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "recv");
      queue_destroy (queue);
      return;
    }
    /* try again */
    left = GNUNET_TIME_absolute_get_remaining (queue->timeout);
    if (0 != left.rel_value_us)
    {
      queue->read_task =
        GNUNET_SCHEDULER_add_read_net (left, queue->sock, &queue_read, queue);
      return;
    }
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Queue %p was idle for %s, disconnecting\n",
                queue,
                GNUNET_STRINGS_relative_time_to_string (
                  GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
                  GNUNET_YES));
    queue_destroy (queue);
    return;
  }
  if (0 == rcvd)
  {
    /* Orderly shutdown of connection */
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Socket for queue %p seems to have been closed\n", queue);
    queue_destroy (queue);
    return;
  }
  queue->timeout =
    GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT);
  queue->cread_off += rcvd;
  while ((queue->pread_off < sizeof(queue->pread_buf)) &&
         (queue->cread_off > 0))
  {
    size_t max = GNUNET_MIN (sizeof(queue->pread_buf) - queue->pread_off,
                             queue->cread_off);
    size_t done;
    size_t total;
    size_t old_pread_off = queue->pread_off;
 
    GNUNET_assert (0 ==
                   gcry_cipher_decrypt (queue->in_cipher,
                                        &queue->pread_buf[queue->pread_off],
                                        max,
                                        queue->cread_buf,
                                        max));
    queue->pread_off += max;
    total = 0;
    while (0 != (done = try_handle_plaintext (queue)))
    {
      /* 'done' bytes of plaintext were used, shift buffer */
      GNUNET_assert (done <= queue->pread_off);
      /* NOTE: this memmove() could possibly sometimes be
         avoided if we pass 'total' into try_handle_plaintext()
         and use it at an offset into the buffer there! */
      memmove (queue->pread_buf,
               &queue->pread_buf[done],
               queue->pread_off - done);
      queue->pread_off -= done;
      total += done;
      /* The last plaintext was a rekey, abort for now */
      if (GNUNET_YES == queue->rekeyed)
        break;
    }
    /* when we encounter a rekey message, the decryption above uses the
       wrong key for everything after the rekey; in that case, we have
       to re-do the decryption at 'total' instead of at 'max'.
       However, we have to take into account that the plaintext buffer may have
       already contained data and not jumped too far ahead in the ciphertext.
       If there is no rekey and the last message is incomplete (max > total),
       it is safe to keep the decryption so we shift by 'max' */
    if (GNUNET_YES == queue->rekeyed)
    {
      max = total - old_pread_off;
      queue->rekeyed = GNUNET_NO;
      queue->pread_off = 0;
    }
    memmove (queue->cread_buf, &queue->cread_buf[max], queue->cread_off - max);
    queue->cread_off -= max;
  }
  if (BUF_SIZE == queue->cread_off)
    return; /* buffer full, suspend reading */
  left = GNUNET_TIME_absolute_get_remaining (queue->timeout);
  if (0 != left.rel_value_us)
  {
    if (max_queue_length > queue->backpressure)
    {
      /* continue reading */
      queue->read_task =
        GNUNET_SCHEDULER_add_read_net (left, queue->sock, &queue_read, queue);
    }
    return;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Queue %p was idle for %s, disconnecting\n",
              queue,
              GNUNET_STRINGS_relative_time_to_string (
                GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
                GNUNET_YES));
  queue_destroy (queue);
}
 
 
static struct sockaddr *
tcp_address_to_sockaddr_numeric_v6 (socklen_t *sock_len,
                                    struct sockaddr_in6 v6,
                                    unsigned int port)
{
  struct sockaddr *in;
 
  v6.sin6_family = AF_INET6;
  v6.sin6_port = htons ((uint16_t) port);
#if HAVE_SOCKADDR_IN_SIN_LEN
  v6.sin6_len = sizeof(struct sockaddr_in6);
#endif
  v6.sin6_flowinfo = 0;
  v6.sin6_scope_id = 0;
  in = GNUNET_memdup (&v6, sizeof(v6));
  *sock_len = sizeof(struct sockaddr_in6);
 
  return in;
}
 
 
static struct sockaddr *
tcp_address_to_sockaddr_numeric_v4 (socklen_t *sock_len,
                                    struct sockaddr_in v4,
                                    unsigned int port)
{
  struct sockaddr *in;
 
  v4.sin_family = AF_INET;
  v4.sin_port = htons ((uint16_t) port);
#if HAVE_SOCKADDR_IN_SIN_LEN
  v4.sin_len = sizeof(struct sockaddr_in);
#endif
  in = GNUNET_memdup (&v4, sizeof(v4));
  *sock_len = sizeof(struct sockaddr_in);
  return in;
}
 
 
static struct PortOnlyIpv4Ipv6 *
tcp_address_to_sockaddr_port_only (const char *bindto, unsigned int *port)
{
  struct PortOnlyIpv4Ipv6 *po;
  struct sockaddr_in *i4;
  struct sockaddr_in6 *i6;
  socklen_t sock_len_ipv4;
  socklen_t sock_len_ipv6;
 
  /* interpreting value as just a PORT number */
  if (*port > UINT16_MAX)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "BINDTO specification `%s' invalid: value too large for port\n",
                bindto);
    return NULL;
  }
 
  po = GNUNET_new (struct PortOnlyIpv4Ipv6);
 
  if (GNUNET_YES == disable_v6)
  {
    i4 = GNUNET_malloc (sizeof(struct sockaddr_in));
    po->addr_ipv4 = tcp_address_to_sockaddr_numeric_v4 (&sock_len_ipv4, *i4,
                                                        *port);
    po->addr_len_ipv4 = sock_len_ipv4;
  }
  else
  {
 
    i4 = GNUNET_malloc (sizeof(struct sockaddr_in));
    po->addr_ipv4 = tcp_address_to_sockaddr_numeric_v4 (&sock_len_ipv4, *i4,
                                                        *port);
    po->addr_len_ipv4 = sock_len_ipv4;
 
    i6 = GNUNET_malloc (sizeof(struct sockaddr_in6));
    po->addr_ipv6 = tcp_address_to_sockaddr_numeric_v6 (&sock_len_ipv6, *i6,
                                                        *port);
 
    po->addr_len_ipv6 = sock_len_ipv6;
 
    GNUNET_free (i6);
  }
 
  GNUNET_free (i4);
 
  return po;
}
 
 
static char *
extract_address (const char *bindto)
{
  char *addr;
  char *start;
  char *token;
  char *cp;
  char *rest = NULL;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "extract address with bindto %s\n",
              bindto);
 
  if (NULL == bindto)
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "bindto is NULL\n");
 
  cp = GNUNET_strdup (bindto);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "extract address 2\n");
 
  start = cp;
  if (('[' == *cp) && (']' == cp[strlen (cp) - 1]))
  {
    start++;   /* skip over '['*/
    cp[strlen (cp) - 1] = '\0';  /* eat ']'*/
    addr = GNUNET_strdup (start);
  }
  else
  {
    token = strtok_r (cp, "]", &rest);
    if (strlen (bindto) == strlen (token))
    {
      token = strtok_r (cp, ":", &rest);
      addr = GNUNET_strdup (token);
    }
    else
    {
      token++;
      addr = GNUNET_strdup (token);
    }
  }
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "tcp address: %s\n",
              addr);
  GNUNET_free (cp);
  return addr;
}
 
 
static unsigned int
extract_port (const char *addr_and_port)
{
  unsigned int port;
  char dummy[2];
  char *token;
  char *addr;
  char *colon;
  char *cp;
  char *rest = NULL;
 
  if (NULL != addr_and_port)
  {
    cp = GNUNET_strdup (addr_and_port);
    token = strtok_r (cp, "]", &rest);
    if (strlen (addr_and_port) == strlen (token))
    {
      colon = strrchr (cp, ':');
      if (NULL == colon)
      {
        GNUNET_free (cp);
        return 0;
      }
      addr = colon;
      addr++;
    }
    else
    {
      token = strtok_r (NULL, "]", &rest);
      if (NULL == token)
      {
        GNUNET_free (cp);
        return 0;
      }
      else
      {
        addr = token;
        addr++;
      }
    }
 
 
    if (1 == sscanf (addr, "%u%1s", &port, dummy))
    {
      /* interpreting value as just a PORT number */
      if (port > UINT16_MAX)
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                    "Port `%u' invalid: value too large for port\n",
                    port);
        GNUNET_free (cp);
        return 0;
      }
    }
    else
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "BINDTO specification invalid: last ':' not followed by number\n");
      GNUNET_free (cp);
      return 0;
    }
    GNUNET_free (cp);
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "return 0\n");
    /* interpret missing port as 0, aka pick any free one */
    port = 0;
  }
 
  return port;
}
 
 
static struct sockaddr *
tcp_address_to_sockaddr (const char *bindto, socklen_t *sock_len)
{
  struct sockaddr *in;
  unsigned int port;
  struct sockaddr_in v4;
  struct sockaddr_in6 v6;
  char *start;
 
  memset (&v4, 0, sizeof(v4));
  start = extract_address (bindto);
  GNUNET_assert (NULL != start);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "start %s\n",
              start);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "!bindto %s\n",
              bindto);
 
 
  if (1 == inet_pton (AF_INET, start, &v4.sin_addr))
  {
    port = extract_port (bindto);
 
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "port %u\n",
                port);
 
    in = tcp_address_to_sockaddr_numeric_v4 (sock_len, v4, port);
  }
  else if (1 == inet_pton (AF_INET6, start, &v6.sin6_addr))
  {
    port = extract_port (bindto);
    in = tcp_address_to_sockaddr_numeric_v6 (sock_len, v6, port);
  }
  else
  {
    GNUNET_assert (0);
  }
 
  GNUNET_free (start);
  return in;
}
 
 
static void
mq_send (struct GNUNET_MQ_Handle *mq,
         const struct GNUNET_MessageHeader *msg,
         void *impl_state)
{
  struct Queue *queue = impl_state;
  uint16_t msize = ntohs (msg->size);
  struct TCPBox box;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "In MQ send. Queue finishing: %s; write task running: %s\n",
              (GNUNET_YES == queue->finishing) ? "yes" : "no",
              (NULL == queue->write_task) ? "yes" : "no");
  GNUNET_assert (mq == queue->mq);
  queue->mq_awaits_continue = GNUNET_YES;
  if (GNUNET_YES == queue->finishing)
    return; /* this queue is dying, drop msg */
  GNUNET_assert (0 == queue->pwrite_off);
  box.header.type = htons (GNUNET_MESSAGE_TYPE_COMMUNICATOR_TCP_BOX);
  box.header.size = htons (msize);
  calculate_hmac (&queue->out_hmac, msg, msize, &box.hmac);
  memcpy (&queue->pwrite_buf[queue->pwrite_off], &box, sizeof(box));
  queue->pwrite_off += sizeof(box);
  memcpy (&queue->pwrite_buf[queue->pwrite_off], msg, msize);
  queue->pwrite_off += msize;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "%lu bytes of plaintext to send\n", queue->pwrite_off);
  GNUNET_assert (NULL != queue->sock);
  if (NULL == queue->write_task)
    queue->write_task =
      GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                      queue->sock,
                                      &queue_write,
                                      queue);
}
 
 
static void
mq_destroy (struct GNUNET_MQ_Handle *mq, void *impl_state)
{
  struct Queue *queue = impl_state;
 
  if (mq == queue->mq)
  {
    queue->mq = NULL;
    queue_finish (queue);
  }
}
 
 
static void
mq_cancel (struct GNUNET_MQ_Handle *mq, void *impl_state)
{
  struct Queue *queue = impl_state;
 
  GNUNET_assert (0 != queue->pwrite_off);
  queue->pwrite_off = 0;
}
 
 
static void
mq_error (void *cls, enum GNUNET_MQ_Error error)
{
  struct Queue *queue = cls;
 
  GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
              "MQ error in queue to %s: %d\n",
              GNUNET_i2s (&queue->target),
              (int) error);
  queue_finish (queue);
}
 
 
static void
boot_queue (struct Queue *queue)
{
  queue->nt =
    GNUNET_NT_scanner_get_type (is, queue->address, queue->address_len);
  (void) GNUNET_CONTAINER_multihashmap_put (
    queue_map,
    &queue->key,
    queue,
    GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
  GNUNET_STATISTICS_set (stats,
                         "# queues active",
                         GNUNET_CONTAINER_multihashmap_size (queue_map),
                         GNUNET_NO);
  queue->timeout =
    GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT);
  queue->mq = GNUNET_MQ_queue_for_callbacks (&mq_send,
                                             &mq_destroy,
                                             &mq_cancel,
                                             queue,
                                             NULL,
                                             &mq_error,
                                             queue);
}
 
 
static void
transmit_kx (struct Queue *queue,
             const struct GNUNET_CRYPTO_HpkeEncapsulation *c)
{
  struct TcpHandshakeSignature ths;
  struct TCPConfirmation tc;
 
  memcpy (queue->cwrite_buf, c, sizeof(*c));
  queue->cwrite_off = sizeof(*c);
  /* compute 'tc' and append in encrypted format to cwrite_buf */
  tc.sender = my_identity;
  tc.monotonic_time =
    GNUNET_TIME_absolute_hton (GNUNET_TIME_absolute_get_monotonic (cfg));
  GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE,
                              &tc.challenge,
                              sizeof(tc.challenge));
  ths.purpose.purpose = htonl (
    GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_HANDSHAKE);
  ths.purpose.size = htonl (sizeof(ths));
  ths.sender = my_identity;
  ths.receiver = queue->target;
  ths.ephemeral = *c;
  ths.monotonic_time = tc.monotonic_time;
  ths.challenge = tc.challenge;
  GNUNET_CRYPTO_eddsa_sign (my_private_key,
                            &ths,
                            &tc.sender_sig);
  GNUNET_assert (0 ==
                 gcry_cipher_encrypt (queue->out_cipher,
                                      &queue->cwrite_buf[queue->cwrite_off],
                                      sizeof(tc),
                                      &tc,
                                      sizeof(tc)));
  queue->challenge = tc.challenge;
  queue->cwrite_off += sizeof(tc);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "handshake written\n");
}
 
 
static void
start_initial_kx_out (struct Queue *queue)
{
  struct GNUNET_CRYPTO_HpkeEncapsulation c;
  struct GNUNET_ShortHashCode k;
 
  GNUNET_CRYPTO_hpke_elligator_kem_encaps (&queue->target_hpke_key,
                                           &c, &k);
  setup_out_cipher (queue, &k);
  transmit_kx (queue, &c);
}
 
 
static void
handshake_monotime_store_cb (void *cls, int success)
{
  struct Queue *queue = cls;
  if (GNUNET_OK != success)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to store handshake monotonic time in PEERSTORE!\n");
  }
  queue->handshake_monotime_sc = NULL;
  GNUNET_PEERSTORE_iteration_next (queue->handshake_ack_monotime_get, 1);
}
 
 
static void
handshake_monotime_cb (void *cls,
                       const struct GNUNET_PEERSTORE_Record *record,
                       const char *emsg)
{
  struct Queue *queue = cls;
  struct GNUNET_TIME_AbsoluteNBO *mtbe;
  struct GNUNET_TIME_Absolute mt;
  const struct GNUNET_PeerIdentity *pid;
  struct GNUNET_TIME_AbsoluteNBO *handshake_monotonic_time;
 
  (void) emsg;
 
  handshake_monotonic_time = &queue->handshake_monotonic_time;
  pid = &queue->target;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "tcp handshake with us %s\n",
              GNUNET_i2s (&my_identity));
  if (NULL == record)
  {
    queue->handshake_monotime_get = NULL;
    return;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "tcp handshake from peer %s\n",
              GNUNET_i2s (pid));
  if (sizeof(*mtbe) != record->value_size)
  {
    GNUNET_PEERSTORE_iteration_next (queue->handshake_ack_monotime_get, 1);
    GNUNET_break (0);
    return;
  }
  mtbe = record->value;
  mt = GNUNET_TIME_absolute_ntoh (*mtbe);
  if (mt.abs_value_us > GNUNET_TIME_absolute_ntoh (
        queue->handshake_monotonic_time).abs_value_us)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Queue from %s dropped, handshake monotime in the past\n",
                GNUNET_i2s (&queue->target));
    GNUNET_break (0);
    GNUNET_PEERSTORE_iteration_stop (queue->handshake_ack_monotime_get);
    queue->handshake_ack_monotime_get = NULL;
    queue_finish (queue);
    return;
  }
  queue->handshake_monotime_sc = GNUNET_PEERSTORE_store (peerstore,
                                                         "transport_tcp_communicator",
                                                         pid,
                                                         GNUNET_PEERSTORE_TRANSPORT_TCP_COMMUNICATOR_HANDSHAKE,
                                                         handshake_monotonic_time,
                                                         sizeof(*
                                                                handshake_monotonic_time),
                                                         GNUNET_TIME_UNIT_FOREVER_ABS,
                                                         GNUNET_PEERSTORE_STOREOPTION_REPLACE,
                                                         &
                                                         handshake_monotime_store_cb,
                                                         queue);
}
 
 
static int
decrypt_and_check_tc (struct Queue *queue,
                      struct TCPConfirmation *tc,
                      char *ibuf)
{
  struct TcpHandshakeSignature ths;
  enum GNUNET_GenericReturnValue ret;
 
  GNUNET_assert (
    0 ==
    gcry_cipher_decrypt (queue->in_cipher,
                         tc,
                         sizeof(*tc),
                         &ibuf[sizeof(struct GNUNET_CRYPTO_EcdhePublicKey)],
                         sizeof(*tc)));
  ths.purpose.purpose = htonl (
    GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_HANDSHAKE);
  ths.purpose.size = htonl (sizeof(ths));
  ths.sender = tc->sender;
  ths.receiver = my_identity;
  memcpy (&ths.ephemeral, ibuf, sizeof(struct GNUNET_CRYPTO_EcdhePublicKey));
  ths.monotonic_time = tc->monotonic_time;
  ths.challenge = tc->challenge;
  ret = GNUNET_CRYPTO_eddsa_verify (
    GNUNET_SIGNATURE_PURPOSE_COMMUNICATOR_TCP_HANDSHAKE,
    &ths,
    &tc->sender_sig,
    &tc->sender.public_key);
  if (GNUNET_YES == ret)
    queue->handshake_monotime_get =
      GNUNET_PEERSTORE_iteration_start (peerstore,
                                        "transport_tcp_communicator",
                                        &queue->target,
                                        GNUNET_PEERSTORE_TRANSPORT_TCP_COMMUNICATOR_HANDSHAKE,
                                        &handshake_monotime_cb,
                                        queue);
  return ret;
}
 
 
static void
queue_read_kx (void *cls)
{
  struct Queue *queue = cls;
  ssize_t rcvd;
  struct GNUNET_TIME_Relative left;
  struct TCPConfirmation tc;
 
  queue->read_task = NULL;
  left = GNUNET_TIME_absolute_get_remaining (queue->timeout);
  if (0 == left.rel_value_us)
  {
    queue_destroy (queue);
    return;
  }
  rcvd = GNUNET_NETWORK_socket_recv (queue->sock,
                                     &queue->cread_buf[queue->cread_off],
                                     BUF_SIZE - queue->cread_off);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Received %lu bytes to write in buffer of size %lu for KX from queue %p (expires in %"
              PRIu64 ")\n",
              rcvd, BUF_SIZE - queue->cread_off, queue, left.rel_value_us);
  if (-1 == rcvd)
  {
    if ((EAGAIN != errno) && (EINTR != errno))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "recv");
      queue_destroy (queue);
      return;
    }
    queue->read_task =
      GNUNET_SCHEDULER_add_read_net (left, queue->sock, &queue_read_kx, queue);
    return;
  }
  if (0 == rcvd)
  {
    /* Orderly shutdown of connection */
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Socket for queue %p seems to have been closed\n", queue);
    queue_destroy (queue);
    return;
  }
  queue->cread_off += rcvd;
  if (queue->cread_off < INITIAL_KX_SIZE)
  {
    /* read more */
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "%lu/%lu bytes of KX read. Rescheduling...\n",
                queue->cread_off, INITIAL_KX_SIZE);
    queue->read_task =
      GNUNET_SCHEDULER_add_read_net (left, queue->sock, &queue_read_kx, queue);
    return;
  }
  /* we got all the data, let's find out who we are talking to! */
  setup_in_cipher_elligator (
    (const struct GNUNET_CRYPTO_HpkeEncapsulation*)
    queue->cread_buf,
    queue);
  if (GNUNET_OK != decrypt_and_check_tc (queue, &tc, queue->cread_buf))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Invalid TCP KX received from %s\n",
                GNUNET_a2s (queue->address, queue->address_len));
    queue_destroy (queue);
    return;
  }
  if (0 !=
      memcmp (&tc.sender, &queue->target, sizeof(struct GNUNET_PeerIdentity)))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Invalid sender in TCP KX received from %s\n",
                GNUNET_a2s (queue->address, queue->address_len));
    queue_destroy (queue);
    return;
  }
  send_challenge (tc.challenge, queue);
  queue->write_task =
    GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                    queue->sock,
                                    &queue_write,
                                    queue);
 
  /* update queue timeout */
  queue->timeout =
    GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT);
  /* prepare to continue with regular read task immediately */
  memmove (queue->cread_buf,
           &queue->cread_buf[INITIAL_KX_SIZE],
           queue->cread_off - (INITIAL_KX_SIZE));
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "cread_off is %lu bytes before adjusting\n",
              queue->cread_off);
  queue->cread_off -= INITIAL_KX_SIZE;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "cread_off set to %lu bytes\n",
              queue->cread_off);
  queue->read_task = GNUNET_SCHEDULER_add_now (&queue_read, queue);
}
 
 
static void
proto_read_kx (void *cls)
{
  struct ProtoQueue *pq = cls;
  ssize_t rcvd;
  struct GNUNET_TIME_Relative left;
  struct Queue *queue;
  struct TCPConfirmation tc;
  GNUNET_SCHEDULER_TaskCallback read_task;
 
  pq->read_task = NULL;
  left = GNUNET_TIME_absolute_get_remaining (pq->timeout);
  if (0 == left.rel_value_us)
  {
    free_proto_queue (pq);
    return;
  }
  rcvd = GNUNET_NETWORK_socket_recv (pq->sock,
                                     &pq->ibuf[pq->ibuf_off],
                                     sizeof(pq->ibuf) - pq->ibuf_off);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Proto received %lu bytes for KX\n", rcvd);
  if (-1 == rcvd)
  {
    if ((EAGAIN != errno) && (EINTR != errno))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_DEBUG, "recv");
      free_proto_queue (pq);
      return;
    }
    /* try again */
    pq->read_task =
      GNUNET_SCHEDULER_add_read_net (left, pq->sock, &proto_read_kx, pq);
    return;
  }
  if (0 == rcvd)
  {
    /* Orderly shutdown of connection */
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Socket for proto queue %p seems to have been closed\n", pq);
    free_proto_queue (pq);
    return;
  }
  pq->ibuf_off += rcvd;
  if (sizeof (struct TCPNATProbeMessage) == pq->ibuf_off)
  {
    struct TCPNATProbeMessage *pm = (struct TCPNATProbeMessage *) pq->ibuf;
 
    check_and_remove_pending_reversal (pq->address, pq->address->sa_family,
                                       &pm->clientIdentity);
 
    queue = GNUNET_new (struct Queue);
    queue->target = pm->clientIdentity;
    eddsa_pub_to_hpke_key (&queue->target.public_key, &queue->target_hpke_key);
    queue->cs = GNUNET_TRANSPORT_CS_OUTBOUND;
    read_task = &queue_read_kx;
  }
  else if (pq->ibuf_off > sizeof(pq->ibuf))
  {
    /* read more */
    pq->read_task =
      GNUNET_SCHEDULER_add_read_net (left, pq->sock, &proto_read_kx, pq);
    return;
  }
  else
  {
    /* we got all the data, let's find out who we are talking to! */
    queue = GNUNET_new (struct Queue);
    setup_in_cipher_elligator (
      (const struct GNUNET_CRYPTO_HpkeEncapsulation *) pq->
      ibuf,
      queue);
    if (GNUNET_OK != decrypt_and_check_tc (queue, &tc, pq->ibuf))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Invalid TCP KX received from %s\n",
                  GNUNET_a2s (pq->address, pq->address_len));
      gcry_cipher_close (queue->in_cipher);
      GNUNET_free (queue);
      free_proto_queue (pq);
      return;
    }
    queue->target = tc.sender;
    eddsa_pub_to_hpke_key (&queue->target.public_key, &queue->target_hpke_key);
    queue->cs = GNUNET_TRANSPORT_CS_INBOUND;
    read_task = &queue_read;
  }
  queue->address = pq->address; /* steals reference */
  queue->address_len = pq->address_len;
  queue->listen_sock = pq->listen_sock;
  queue->sock = pq->sock;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "created queue with target %s\n",
              GNUNET_i2s (&queue->target));
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "start kx proto\n");
 
  start_initial_kx_out (queue);
  boot_queue (queue);
  queue->read_task =
    GNUNET_SCHEDULER_add_read_net (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
                                   queue->sock,
                                   read_task,
                                   queue);
  queue->write_task =
    GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                    queue->sock,
                                    &queue_write,
                                    queue);
  // TODO To early! Move it somewhere else.
  // send_challenge (tc.challenge, queue);
  queue->challenge_received = tc.challenge;
 
  GNUNET_CONTAINER_DLL_remove (proto_head, proto_tail, pq);
  GNUNET_free (pq);
}
 
 
static struct ProtoQueue *
create_proto_queue (struct GNUNET_NETWORK_Handle *sock,
                    struct sockaddr *in,
                    socklen_t addrlen)
{
  struct ProtoQueue *pq = GNUNET_new (struct ProtoQueue);
 
  if (NULL == sock)
  {
    // sock = GNUNET_CONNECTION_create_from_sockaddr (AF_INET, addr, addrlen);
    sock = GNUNET_NETWORK_socket_create (in->sa_family, SOCK_STREAM, 0);
    if (NULL == sock)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "socket(%d) failed: %s",
                  in->sa_family,
                  strerror (errno));
      GNUNET_free (in);
      GNUNET_free (pq);
      return NULL;
    }
    if ((GNUNET_OK != GNUNET_NETWORK_socket_connect (sock, in, addrlen)) &&
        (errno != EINPROGRESS))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "connect to `%s' failed: %s",
                  GNUNET_a2s (in, addrlen),
                  strerror (errno));
      GNUNET_NETWORK_socket_close (sock);
      GNUNET_free (in);
      GNUNET_free (pq);
      return NULL;
    }
  }
  pq->address_len = addrlen;
  pq->address = in;
  pq->timeout = GNUNET_TIME_relative_to_absolute (PROTO_QUEUE_TIMEOUT);
  pq->sock = sock;
  pq->read_task = GNUNET_SCHEDULER_add_read_net (PROTO_QUEUE_TIMEOUT,
                                                 pq->sock,
                                                 &proto_read_kx,
                                                 pq);
  GNUNET_CONTAINER_DLL_insert (proto_head, proto_tail, pq);
 
  return pq;
}
 
 
static void
listen_cb (void *cls)
{
  struct sockaddr_storage in;
  socklen_t addrlen;
  struct GNUNET_NETWORK_Handle *sock;
  struct ListenTask *lt;
  struct sockaddr *in_addr;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "listen_cb\n");
 
  lt = cls;
 
  lt->listen_task = NULL;
  GNUNET_assert (NULL != lt->listen_sock);
  addrlen = sizeof(in);
  memset (&in, 0, sizeof(in));
  sock = GNUNET_NETWORK_socket_accept (lt->listen_sock,
                                       (struct sockaddr*) &in,
                                       &addrlen);
  if ((NULL == sock) && ((EMFILE == errno) || (ENFILE == errno)))
    return; /* system limit reached, wait until connection goes down */
  lt->listen_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                                   lt->listen_sock,
                                                   &listen_cb,
                                                   lt);
  if ((NULL == sock) && ((EAGAIN == errno) || (ENOBUFS == errno)))
    return;
  if (NULL == sock)
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "accept");
    return;
  }
  in_addr = GNUNET_memdup (&in, addrlen);
  create_proto_queue (sock, in_addr, addrlen);
}
 
 
static void
pending_reversal_timeout (void *cls)
{
  struct sockaddr *in = cls;
  struct PendingReversal *pending_reversal;
  struct GNUNET_HashCode key;
 
  GNUNET_CRYPTO_hash (in,
                      sizeof(struct sockaddr),
                      &key);
  pending_reversal = GNUNET_CONTAINER_multihashmap_get (pending_reversals,
                                                        &key);
 
  GNUNET_assert (NULL != pending_reversal);
 
  if (GNUNET_NO == GNUNET_CONTAINER_multihashmap_remove (pending_reversals,
                                                         &key,
                                                         pending_reversal))
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "No pending reversal found for address %s\n",
                GNUNET_a2s (in, sizeof (struct sockaddr)));
  GNUNET_free (pending_reversal->in);
  GNUNET_free (pending_reversal);
}
 
 
static int
mq_init (void *cls, const struct GNUNET_PeerIdentity *peer, const char *address)
{
  struct sockaddr *in;
  socklen_t in_len = 0;
  const char *path;
  struct sockaddr_in *v4;
  struct sockaddr_in6 *v6;
  unsigned int is_natd = GNUNET_NO;
  struct GNUNET_HashCode key;
  struct GNUNET_HashCode queue_map_key;
  struct GNUNET_HashContext *hsh;
  struct Queue *queue;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Connecting to %s at %s\n",
              GNUNET_i2s (peer),
              address);
  if (0 != strncmp (address,
                    COMMUNICATOR_ADDRESS_PREFIX "-",
                    strlen (COMMUNICATOR_ADDRESS_PREFIX "-")))
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  path = &address[strlen (COMMUNICATOR_ADDRESS_PREFIX "-")];
  in = tcp_address_to_sockaddr (path, &in_len);
 
  if (NULL == in)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Failed to setup TCP socket address\n");
    return GNUNET_SYSERR;
  }
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "in %s\n",
              GNUNET_a2s (in, in_len));
 
  hsh = GNUNET_CRYPTO_hash_context_start ();
  GNUNET_CRYPTO_hash_context_read (hsh, address, strlen (address));
  GNUNET_CRYPTO_hash_context_read (hsh, peer, sizeof (*peer));
  GNUNET_CRYPTO_hash_context_finish (hsh, &queue_map_key);
  queue = GNUNET_CONTAINER_multihashmap_get (queue_map, &queue_map_key);
 
  if (NULL != queue)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Queue for %s already exists or is in construction\n", address);
    GNUNET_free (in);
    return GNUNET_NO;
  }
  switch (in->sa_family)
  {
  case AF_INET:
    v4 = (struct sockaddr_in *) in;
    if (0 == v4->sin_port)
    {
      is_natd = GNUNET_YES;
      GNUNET_CRYPTO_hash (in,
                          sizeof(struct sockaddr),
                          &key);
      if (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains (
            pending_reversals,
            &key))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "There is already a request reversal for `%s'at `%s'\n",
                    GNUNET_i2s (peer),
                    address);
        GNUNET_free (in);
        return GNUNET_SYSERR;
      }
    }
    break;
 
  case AF_INET6:
    if (GNUNET_YES == disable_v6)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "IPv6 disabled, skipping %s\n", address);
      GNUNET_free (in);
      return GNUNET_SYSERR;
    }
    v6 = (struct sockaddr_in6 *) in;
    if (0 == v6->sin6_port)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "Request reversal for `%s' at `%s' not possible for an IPv6 address\n",
                  GNUNET_i2s (peer),
                  address);
      GNUNET_free (in);
      return GNUNET_SYSERR;
    }
    break;
 
  default:
    GNUNET_assert (0);
  }
 
  if (GNUNET_YES == is_natd)
  {
    struct sockaddr_in local_sa;
    struct PendingReversal *pending_reversal;
 
    memset (&local_sa, 0, sizeof(local_sa));
    local_sa.sin_family = AF_INET;
    local_sa.sin_port = htons (bind_port);
    /* We leave sin_address at 0, let the kernel figure it out,
       even if our bind() is more specific.  (May want to reconsider
       later.) */
    if (GNUNET_OK != GNUNET_NAT_request_reversal (nat, &local_sa, v4))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "request reversal for `%s' at `%s' failed\n",
                  GNUNET_i2s (peer),
                  address);
      GNUNET_free (in);
      return GNUNET_SYSERR;
    }
    pending_reversal = GNUNET_new (struct PendingReversal);
    pending_reversal->in = in;
    GNUNET_assert (GNUNET_OK ==
                   GNUNET_CONTAINER_multihashmap_put (pending_reversals,
                                                      &key,
                                                      pending_reversal,
                                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
    pending_reversal->target = *peer;
    pending_reversal->timeout_task = GNUNET_SCHEDULER_add_delayed (NAT_TIMEOUT,
                                                                   &
                                                                   pending_reversal_timeout,
                                                                   in);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Created NAT WAIT connection to `%s' at `%s'\n",
                GNUNET_i2s (peer),
                GNUNET_a2s (in, sizeof (struct sockaddr)));
  }
  else
  {
    struct GNUNET_NETWORK_Handle *sock;
 
    sock = GNUNET_NETWORK_socket_create (in->sa_family, SOCK_STREAM,
                                         IPPROTO_TCP);
    if (NULL == sock)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "socket(%d) failed: %s",
                  in->sa_family,
                  strerror (errno));
      GNUNET_free (in);
      return GNUNET_SYSERR;
    }
    if ((GNUNET_OK != GNUNET_NETWORK_socket_connect (sock, in, in_len)) &&
        (errno != EINPROGRESS))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "connect to `%s' failed: %s",
                  address,
                  strerror (errno));
      GNUNET_NETWORK_socket_close (sock);
      GNUNET_free (in);
      return GNUNET_SYSERR;
    }
 
    queue = GNUNET_new (struct Queue);
    queue->target = *peer;
    eddsa_pub_to_hpke_key (&queue->target.public_key, &queue->target_hpke_key);
    queue->key = queue_map_key;
    queue->address = in;
    queue->address_len = in_len;
    queue->sock = sock;
    queue->cs = GNUNET_TRANSPORT_CS_OUTBOUND;
    boot_queue (queue);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "booted queue with target %s\n",
                GNUNET_i2s (&queue->target));
    // queue->mq_awaits_continue = GNUNET_YES;
    queue->read_task =
      GNUNET_SCHEDULER_add_read_net (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
                                     queue->sock,
                                     &queue_read_kx,
                                     queue);
 
 
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "start kx mq_init\n");
 
    start_initial_kx_out (queue);
    queue->write_task =
      GNUNET_SCHEDULER_add_write_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                      queue->sock,
                                      &queue_write,
                                      queue);
  }
 
  return GNUNET_OK;
}
 
 
static int
get_lt_delete_it (void *cls,
                  const struct GNUNET_HashCode *key,
                  void *value)
{
  struct ListenTask *lt = value;
 
  (void) cls;
  (void) key;
  if (NULL != lt->listen_task)
  {
    GNUNET_SCHEDULER_cancel (lt->listen_task);
    lt->listen_task = NULL;
  }
  if (NULL != lt->listen_sock)
  {
    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (lt->listen_sock));
    lt->listen_sock = NULL;
  }
  GNUNET_free (lt);
  return GNUNET_OK;
}
 
 
static int
get_queue_delete_it (void *cls,
                     const struct GNUNET_HashCode *target,
                     void *value)
{
  struct Queue *queue = value;
 
  (void) cls;
  (void) target;
  queue_destroy (queue);
  return GNUNET_OK;
}
 
 
static void
do_shutdown (void *cls)
{
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Shutdown %s!\n",
              shutdown_running ? "running" : "not running");
 
  if (GNUNET_YES == shutdown_running)
    return;
  else
    shutdown_running = GNUNET_YES;
 
  while (NULL != proto_head)
    free_proto_queue (proto_head);
  if (NULL != nat)
  {
    GNUNET_NAT_unregister (nat);
    nat = NULL;
  }
  GNUNET_CONTAINER_multihashmap_iterate (pending_reversals,
                                         &pending_reversals_delete_it, NULL);
  GNUNET_CONTAINER_multihashmap_destroy (pending_reversals);
  GNUNET_CONTAINER_multihashmap_iterate (lt_map, &get_lt_delete_it, NULL);
  GNUNET_CONTAINER_multihashmap_destroy (lt_map);
  GNUNET_CONTAINER_multihashmap_iterate (queue_map, &get_queue_delete_it, NULL);
  GNUNET_CONTAINER_multihashmap_destroy (queue_map);
  if (NULL != ch)
  {
    GNUNET_TRANSPORT_communicator_address_remove_all (ch);
    GNUNET_TRANSPORT_communicator_disconnect (ch);
    ch = NULL;
  }
  if (NULL != stats)
  {
    GNUNET_STATISTICS_destroy (stats, GNUNET_YES);
    stats = NULL;
  }
  if (NULL != my_private_key)
  {
    GNUNET_free (my_private_key);
    my_private_key = NULL;
  }
  if (NULL != is)
  {
    GNUNET_NT_scanner_done (is);
    is = NULL;
  }
  if (NULL != pils)
  {
    GNUNET_PILS_disconnect (pils);
    pils = NULL;
  }
  if (NULL != peerstore)
  {
    GNUNET_PEERSTORE_disconnect (peerstore);
    peerstore = NULL;
  }
  if (NULL != resolve_request_handle)
  {
    GNUNET_RESOLVER_request_cancel (resolve_request_handle);
    resolve_request_handle = NULL;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Shutdown done!\n");
}
 
 
static void
enc_notify_cb (void *cls,
               const struct GNUNET_PeerIdentity *sender,
               const struct GNUNET_MessageHeader *msg)
{
  (void) cls;
  (void) sender;
  (void) msg;
  GNUNET_break_op (0);
}
 
 
static void
add_addr (struct sockaddr *in, socklen_t in_len)
{
 
  struct Addresses *saddrs;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "add address %s\n",
              GNUNET_a2s (in, in_len));
 
  saddrs = GNUNET_new (struct Addresses);
  saddrs->addr = in;
  saddrs->addr_len = in_len;
  GNUNET_CONTAINER_DLL_insert (addrs_head, addrs_tail, saddrs);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "after add address %s\n",
              GNUNET_a2s (in, in_len));
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "add address %s\n",
              GNUNET_a2s (saddrs->addr, saddrs->addr_len));
 
  addrs_lens++;
}
 
 
static enum GNUNET_GenericReturnValue
load_ikm ()
{
  char *filename;
  struct GNUNET_DISK_FileHandle *filehandle;
  int ret;
 
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (cfg,
                                               "pils",
                                               "SECRET_KEY_FILE",
                                               &filename))
  {
    LOG (GNUNET_ERROR_TYPE_ERROR,
         "PILS service is lacking initial secret key file configuration setting. Exiting\n");
    return GNUNET_SYSERR;
  }
  if (NULL == filename)
    return GNUNET_SYSERR;
  ret = GNUNET_DISK_file_test_read (filename);
  if (GNUNET_SYSERR == ret)
    return GNUNET_SYSERR;
  if (GNUNET_NO == ret)
  {
    /* File does not exist - generate a new initial secret key and save it */
    // TODO consider the case that the file exists and ist not readable
    GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE,
                                ikm,
                                sizeof ikm);
    if (GNUNET_OK != GNUNET_DISK_directory_create_for_file (filename))
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "PILS service cannot create dir for saving initial secret key file. Exiting\n");
      return GNUNET_SYSERR;
    }
    filehandle = GNUNET_DISK_file_open (filename,
                                        GNUNET_DISK_OPEN_WRITE
                                        | GNUNET_DISK_OPEN_CREATE,
                                        GNUNET_DISK_PERM_USER_READ   // TODO
                                        |                            // would
                                                                     // the
                                                                     // group
                                                                     // need
                                                                     // read
                                                                     // perm?
                                        GNUNET_DISK_PERM_USER_WRITE);
    if (NULL == filehandle)
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "PILS service had an issue with opening the initial secret key file. Exiting\n");
      GNUNET_DISK_file_close (filehandle);
      return GNUNET_SYSERR;
    }
    ret = GNUNET_DISK_file_write (filehandle,
                                  ikm,
                                  sizeof ikm);
    GNUNET_DISK_file_close (filehandle);
    if (sizeof ikm != ret)
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "PILS service had an issue with writing the initial secret key to file. Exiting\n")
      ;
      return GNUNET_SYSERR;
    }
  }
  else
  {
    /* File existes - just read from it */
    off_t size;
    LOG (GNUNET_ERROR_TYPE_DEBUG,
         "PILS is going to read initial secret key from file %s\n",
         filename);
    filehandle = GNUNET_DISK_file_open (filename,
                                        GNUNET_DISK_OPEN_READ,
                                        GNUNET_DISK_PERM_NONE);
    if (NULL == filehandle)
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "  Not able to open file\n");
      return GNUNET_SYSERR;
    }
    if (GNUNET_OK != GNUNET_DISK_file_handle_size (filehandle, &size))
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "  File has the wrong size %lu\n",
           size);
      GNUNET_DISK_file_close (filehandle);
      return GNUNET_SYSERR;
    }
    if (sizeof ikm != size)
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "  Something is wrong with the file size, expected: %lu size, got: %lu\n",
           size,
           sizeof ikm);
      GNUNET_DISK_file_close (filehandle);
      return GNUNET_SYSERR;
    }
    ret = GNUNET_DISK_file_read (filehandle,
                                 ikm,
                                 sizeof ikm);
    GNUNET_DISK_file_close (filehandle);
    if (sizeof ikm != ret)
    {
      LOG (GNUNET_ERROR_TYPE_ERROR,
           "  Read initial secret key with wrong size %u, expected %lu\n", ret,
           sizeof ikm);
      return GNUNET_SYSERR;
    }
 
  }
  return GNUNET_OK;
}
 
 
static int
init_socket (struct sockaddr *addr,
             socklen_t in_len)
{
  struct sockaddr_storage in_sto;
  socklen_t sto_len;
  struct GNUNET_NETWORK_Handle *listen_sock;
  struct ListenTask *lt;
  int sockfd;
  struct GNUNET_HashCode h_sock;
 
  if (NULL == addr)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Address is NULL.\n");
    return GNUNET_SYSERR;
  }
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "address %s\n",
              GNUNET_a2s (addr, in_len));
 
  listen_sock =
    GNUNET_NETWORK_socket_create (addr->sa_family, SOCK_STREAM, IPPROTO_TCP);
  if (NULL == listen_sock)
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "socket");
    return GNUNET_SYSERR;
  }
 
  if (GNUNET_OK != GNUNET_NETWORK_socket_bind (listen_sock, addr, in_len))
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
    GNUNET_NETWORK_socket_close (listen_sock);
    listen_sock = NULL;
    return GNUNET_SYSERR;
  }
 
  if (GNUNET_OK !=
      GNUNET_NETWORK_socket_listen (listen_sock,
                                    5))
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
                         "listen");
    GNUNET_NETWORK_socket_close (listen_sock);
    listen_sock = NULL;
    return GNUNET_SYSERR;
  }
 
  /* We might have bound to port 0, allowing the OS to figure it out;
     thus, get the real IN-address from the socket */
  sto_len = sizeof(in_sto);
 
  if (0 != getsockname (GNUNET_NETWORK_get_fd (listen_sock),
                        (struct sockaddr *) &in_sto,
                        &sto_len))
  {
    memcpy (&in_sto, addr, in_len);
    sto_len = in_len;
  }
 
  // addr = (struct sockaddr *) &in_sto;
  in_len = sto_len;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Bound to `%s'\n",
              GNUNET_a2s ((const struct sockaddr *) &in_sto, sto_len));
  if (NULL == stats)
    stats = GNUNET_STATISTICS_create ("communicator-tcp", cfg);
 
  if (NULL == is)
    is = GNUNET_NT_scanner_init ();
 
  /* start listening */
 
  lt = GNUNET_new (struct ListenTask);
  lt->listen_sock = listen_sock;
 
  lt->listen_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                                   listen_sock,
                                                   &listen_cb,
                                                   lt);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "creating hash\n");
  sockfd = GNUNET_NETWORK_get_fd (lt->listen_sock);
  GNUNET_CRYPTO_hash (&sockfd,
                      sizeof(int),
                      &h_sock);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "creating map\n");
  if (NULL == lt_map)
    lt_map = GNUNET_CONTAINER_multihashmap_create (2, GNUNET_NO);
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "creating map entry\n");
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_CONTAINER_multihashmap_put (lt_map,
                                                    &h_sock,
                                                    lt,
                                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "map entry created\n");
 
  if (NULL == queue_map)
    queue_map = GNUNET_CONTAINER_multihashmap_create (10, GNUNET_NO);
 
  if (NULL == ch)
    ch = GNUNET_TRANSPORT_communicator_connect (cfg,
                                                COMMUNICATOR_CONFIG_SECTION,
                                                COMMUNICATOR_ADDRESS_PREFIX,
                                                GNUNET_TRANSPORT_CC_RELIABLE,
                                                &mq_init,
                                                NULL,
                                                &enc_notify_cb,
                                                NULL,
                                                NULL);
 
  if (NULL == ch)
  {
    GNUNET_break (0);
    if (NULL != resolve_request_handle)
      GNUNET_RESOLVER_request_cancel (resolve_request_handle);
    GNUNET_SCHEDULER_shutdown ();
    return GNUNET_SYSERR;
  }
 
  add_addr (addr, in_len);
  return GNUNET_OK;
 
}
 
 
void
pid_change_cb (void *cls,
               const struct GNUNET_HELLO_Parser *parser,
               const struct GNUNET_HashCode *addr_hash)
{
  LOG (GNUNET_ERROR_TYPE_DEBUG,
       "Got PID to derive from `%s':\n",
       GNUNET_h2s (addr_hash));
  if (NULL == my_private_key)
    my_private_key = GNUNET_new (struct GNUNET_CRYPTO_EddsaPrivateKey);
 
  GNUNET_PILS_derive_pid (sizeof ikm,
                          (uint8_t*) ikm,
                          addr_hash,
                          my_private_key);
  GNUNET_CRYPTO_eddsa_key_get_public (my_private_key,
                                      &my_identity.public_key);
  eddsa_priv_to_hpke_key (my_private_key,
                          &my_x25519_private_key);
}
 
 
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *c)
{
  struct sockaddr *in;
 
  (void) cls;
 
  cfg = c;
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_time (cfg,
                                           COMMUNICATOR_CONFIG_SECTION,
                                           "REKEY_INTERVAL",
                                           &rekey_interval))
  {
    rekey_interval = DEFAULT_REKEY_INTERVAL;
  }
  load_ikm ();
  pils = GNUNET_PILS_connect (cfg, &pid_change_cb, NULL);
  GNUNET_assert (NULL != pils);
  peerstore = GNUNET_PEERSTORE_connect (cfg);
  if (NULL == peerstore)
  {
    GNUNET_free (bindto);
    GNUNET_break (0);
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
 
  GNUNET_SCHEDULER_add_shutdown (&do_shutdown, NULL);
 
  if (1 == sscanf (bindto, "%u%1s", &bind_port, dummy))
  {
    po = tcp_address_to_sockaddr_port_only (bindto, &bind_port);
    addr_len_ipv4 = po->addr_len_ipv4;
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "address po %s\n",
                GNUNET_a2s (po->addr_ipv4, addr_len_ipv4));
    if (NULL != po->addr_ipv4)
    {
      init_socket (po->addr_ipv4, addr_len_ipv4);
    }
    if (NULL != po->addr_ipv6)
    {
      addr_len_ipv6 = po->addr_len_ipv6;
      init_socket (po->addr_ipv6, addr_len_ipv6);
    }
 
    // The following snippet is taken from https://github.com/libp2p/cpp-libp2p/blob/master/example/01-echo/libp2p_echo_client.cpp
    // and needs to be wrapped to c for being able to be called from within
    // this communicator.
    // It is merely there as a reminder of the needed functions and general
    // structure in order to send something via the c++ implementation of
    // libp2p.
    //
    // post(
    //  *context,
    //  [log,
    //   host{std::move(host)},
    //   &echo,
    //   &message,
    //   argv,  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
    //   sch] {
    //    auto server_ma_res =
    //        libp2p::multi::Multiaddress::create(argv[1]);  // NOLINT
    //    if (!server_ma_res) {
    //      log->error("unable to create server multiaddress: {}",
    //                 server_ma_res.error());
    //      std::exit(EXIT_FAILURE);
    //    }
    //    const auto &server_ma = server_ma_res.value();
 
    //    auto server_peer_id_str = server_ma.getPeerId();
    //    if (!server_peer_id_str) {
    //      log->error("unable to get peer id");
    //      std::exit(EXIT_FAILURE);
    //    }
 
    //    auto server_peer_id_res =
    //        libp2p::peer::PeerId::fromBase58(*server_peer_id_str);
    //    if (!server_peer_id_res) {
    //      log->error("Unable to decode peer id from base 58: {}",
    //                 server_peer_id_res.error());
    //      std::exit(EXIT_FAILURE);
    //    }
 
    //    const auto &server_peer_id = server_peer_id_res.value();
 
    //    auto peer_info = libp2p::peer::PeerInfo{server_peer_id, {server_ma}};
 
    //    // create Host object and open a stream through it
    //    host->newStream(
    //        peer_info,
    //        {echo.getProtocolId()},
    //        [log, &echo, &message, sch](auto &&stream_res) {
    //          if (!stream_res) {
    //            log->error("Cannot connect to server: {}", stream_res.error());
    //            std::exit(EXIT_FAILURE);
    //          }
 
    //          auto stream_p = std::move(stream_res.value().stream);
 
    //          auto echo_client = echo.createClient(stream_p);
 
    //          if (message.size() < 120) {
    //            log->info("SENDING {}", message);
    //          } else {
    //            log->info("SENDING {} bytes", message.size());
    //          }
 
    //          sch->schedule(
    //              [log, message, stream = std::move(stream_p), echo_client] {
    //                echo_client->sendAnd(
    //                    message,
    //                    [log,
    //                     stream = std::move(stream)](auto &&response_result) {
    //                      if (response_result.has_error()) {
    //                        log->info("Error happened: {}",
    //                                  response_result.error());
    //                        stream->close(
    //                            [log](auto &&) { std::exit(EXIT_SUCCESS); });
    //                        return;
    //                      }
    //                      auto &resp = response_result.value();
    //                      if (resp.size() < 120) {
    //                        log->info("RESPONSE {}", resp);
    //                      } else {
    //                        log->info("RESPONSE size={}", resp.size());
    //                      }
    //                      stream->close(
    //                          [](auto &&) { std::exit(EXIT_SUCCESS); });
    //                    });
    //              },
    //              std::chrono::milliseconds(1000));
    //        });
    //  });
 
    GNUNET_free (po);
    GNUNET_free (bindto);
    return;
  }
}
 
 
int
main (int argc, char *const *argv)
{
  static const struct GNUNET_GETOPT_CommandLineOption options[] = {
    GNUNET_GETOPT_OPTION_END
  };
  int ret;
 
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Starting tcp communicator\n");
 
  ret = (GNUNET_OK ==
         GNUNET_PROGRAM_run (GNUNET_OS_project_data_gnunet (),
                             argc,
                             argv,
                             "gnunet-communicator-libp2p",
                             _ ("GNUnet libp2p communicator"),
                             options,
                             &run,
                             NULL))
        ? 0
        : 1;
  return ret;
}
 
 
/* end of gnunet-communicator-tcp.c */