/*
 * Copyright (c) 2019 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <sys/socket.h>

#include <vnet/session/application.h>
#include <vnet/session/transport.h>
#include <vnet/session/session.h>
#include <vlib/unix/plugin.h>
#include <vpp/app/version.h>
#include <openssl/pem.h>

#include <vppinfra/lock.h>

#include <quic/quic.h>

#include <quicly/streambuf.h>
#include <picotls/openssl.h>
#include <picotls/pembase64.h>

static quic_main_t quic_main;

static void quic_update_timer (quic_ctx_t * ctx);
static int64_t quic_get_time (quicly_now_cb * self);
static void quic_connection_closed (u32 conn_index);
static void quic_disconnect (u32 ctx_index, u32 thread_index);

#define QUIC_INT_MAX  0x3FFFFFFFFFFFFFFF

u32
quic_ctx_half_open_alloc (void)
{
  quic_main_t *qm = &quic_main;
  u8 will_expand = 0;
  quic_ctx_t *ctx;
  u32 ctx_index;

  pool_get_aligned_will_expand (qm->half_open_ctx_pool, will_expand, 0);
  if (PREDICT_FALSE (will_expand && vlib_num_workers ()))
    {
      clib_rwlock_writer_lock (&qm->half_open_rwlock);
      pool_get (qm->half_open_ctx_pool, ctx);
      ctx_index = ctx - qm->half_open_ctx_pool;
      clib_rwlock_writer_unlock (&qm->half_open_rwlock);
    }
  else
    {
      /* reader lock assumption: only main thread will call pool_get */
      clib_rwlock_reader_lock (&qm->half_open_rwlock);
      pool_get (qm->half_open_ctx_pool, ctx);
      ctx_index = ctx - qm->half_open_ctx_pool;
      clib_rwlock_reader_unlock (&qm->half_open_rwlock);
    }
  memset (ctx, 0, sizeof (*ctx));
  return ctx_index;
}

void
quic_ctx_half_open_free (u32 ho_index)
{
  quic_main_t *qm = &quic_main;
  clib_rwlock_writer_lock (&qm->half_open_rwlock);
  pool_put_index (qm->half_open_ctx_pool, ho_index);
  clib_rwlock_writer_unlock (&qm->half_open_rwlock);
}

quic_ctx_t *
quic_ctx_half_open_get (u32 ctx_index)
{
  quic_main_t *qm = &quic_main;
  clib_rwlock_reader_lock (&qm->half_open_rwlock);
  return pool_elt_at_index (qm->half_open_ctx_pool, ctx_index);
}

void
quic_ctx_half_open_reader_unlock ()
{
  clib_rwlock_reader_unlock (&quic_main.half_open_rwlock);
}

u32
quic_ctx_half_open_index (quic_ctx_t * ctx)
{
  return (ctx - quic_main.half_open_ctx_pool);
}

u32
quic_ctx_alloc ()
{
  u8 thread_index = vlib_get_thread_index ();
  quic_main_t *qm = &quic_main;
  quic_ctx_t *ctx;

  pool_get (qm->ctx_pool[thread_index], ctx);

  memset (ctx, 0, sizeof (quic_ctx_t));
  ctx->c_thread_index = thread_index;
  return ctx - qm->ctx_pool[thread_index];
}

static void
quic_ctx_free (quic_ctx_t * ctx)
{
  QUIC_DBG (2, "Free ctx %u", ctx->c_c_index);
  u32 thread_index = ctx->c_thread_index;
  if (CLIB_DEBUG)
    memset (ctx, 0xfb, sizeof (*ctx));
  pool_put (quic_main.ctx_pool[thread_index], ctx);
}

static quic_ctx_t *
quic_ctx_get (u32 ctx_index)
{
  return pool_elt_at_index (quic_main.ctx_pool[vlib_get_thread_index ()],
			    ctx_index);
}

static quic_ctx_t *
quic_ctx_get_w_thread (u32 ctx_index, u8 thread_index)
{
  return pool_elt_at_index (quic_main.ctx_pool[thread_index], ctx_index);
}

static void
quic_disconnect_transport (quic_ctx_t * ctx)
{
  QUIC_DBG (2, "Called quic_disconnect_transport");
  vnet_disconnect_args_t a = {
    .handle = ctx->c_quic_ctx_id.quic_session,
    .app_index = quic_main.app_index,
  };

  if (vnet_disconnect_session (&a))
    clib_warning ("UDP session disconnect errored");
}

static int
quic_send_datagram (session_t * session, quicly_datagram_t * packet)
{
  QUIC_DBG (2, "Called quic_send_datagram at %ld", quic_get_time (NULL));
  u32 max_enqueue;
  session_dgram_hdr_t hdr;
  int rv;
  u32 len;
  svm_fifo_t *f;
  transport_connection_t *tc;

  len = packet->data.len;
  f = session->tx_fifo;
  tc = session_get_transport (session);

  max_enqueue = svm_fifo_max_enqueue (f);
  if (max_enqueue <= sizeof (session_dgram_hdr_t))
    return 1;

  max_enqueue -= sizeof (session_dgram_hdr_t);

  if (max_enqueue < len)
    return 1;

  // Build packet header for fifo
  hdr.data_length = len;
  hdr.data_offset = 0;
  hdr.is_ip4 = tc->is_ip4;
  clib_memcpy (&hdr.lcl_ip, &tc->lcl_ip, sizeof (ip46_address_t));
  hdr.lcl_port = tc->lcl_port;

  // Read dest address from quicly-provided sockaddr
  if (hdr.is_ip4)
    {
      ASSERT (packet->sa.sa_family == AF_INET);
      struct sockaddr_in *sa4 = (struct sockaddr_in *) &packet->sa;
      hdr.rmt_port = sa4->sin_port;
      hdr.rmt_ip.ip4.as_u32 = sa4->sin_addr.s_addr;
    }
  else
    {
      ASSERT (packet->sa.sa_family == AF_INET6);
      struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &packet->sa;
      hdr.rmt_port = sa6->sin6_port;
      clib_memcpy (&hdr.rmt_ip.ip6, &sa6->sin6_addr, 16);
    }

  rv = svm_fifo_enqueue_nowait (f, sizeof (hdr), (u8 *) & hdr);
  ASSERT (rv == sizeof (hdr));
  if (svm_fifo_enqueue_nowait (f, len, packet->data.base) != len)
    return 1;
  return 0;
}

static int
quic_send_packets (quic_ctx_t * ctx)
{
  //QUIC_DBG (2, "Called quic_send_packets");
  quicly_datagram_t *packets[16];
  session_t *quic_session;
  quicly_conn_t *conn;
  size_t num_packets, i;
  int ret;

  quic_session = session_get_from_handle (ctx->c_quic_ctx_id.quic_session);
  conn = ctx->c_quic_ctx_id.conn;

  if (!conn)
    return 0;

  do
    {
      num_packets = sizeof (packets) / sizeof (packets[0]);
      if ((ret = quicly_send (conn, packets, &num_packets)) == 0)
	{
	  for (i = 0; i != num_packets; ++i)
	    {
	      if (quic_send_datagram (quic_session, packets[i]))
		{
		  QUIC_DBG (2, "quic_send_datagram failed");
		  goto stop_sending;
		}
	      ret = 0;
	      quicly_default_free_packet_cb.cb
		(&quicly_default_free_packet_cb, packets[i]);
	    }
	}
      else
	{
	  QUIC_DBG (2, "quicly_send returned %d, closing connection\n", ret);
	  return ret;
	}
    }
  while (ret == 0 && num_packets == sizeof (packets) / sizeof (packets[0]));

stop_sending:
  if (svm_fifo_set_event (quic_session->tx_fifo))
    session_send_io_evt_to_thread (quic_session->tx_fifo, FIFO_EVENT_APP_TX);

  quic_update_timer (ctx);
  return 0;
}

/*****************************************************************************
 * START QUICLY CALLBACKS
 * Called from QUIC lib
 *****************************************************************************/

static int
quic_on_stop_sending (quicly_stream_t * stream, int error_code)
{
  QUIC_DBG (2, "received STOP_SENDING: %d", error_code);
  return 0;
}

static int
quic_on_receive_reset (quicly_stream_t * stream, int error_code)
{
  QUIC_DBG (2, "received RESET_STREAM: %d", error_code);
  return 0;
}

static int
quic_on_receive (quicly_stream_t * stream, size_t off, const void *src,
		 size_t len)
{
  QUIC_DBG (2, "received data: %lu bytes", len);
  u32 to_enqueue, ctx_id;
  quic_ctx_t *ctx;
  session_t *app_session;
  svm_fifo_t *rx_fifo;
  app_worker_t *app_wrk;

  ctx_id = (u64) * quicly_get_data (stream->conn);
  ctx = quic_ctx_get (ctx_id);
  app_session = session_get_from_handle (ctx->c_quic_ctx_id.app_session);
  rx_fifo = app_session->rx_fifo;
  to_enqueue = svm_fifo_max_enqueue (rx_fifo);
  if (to_enqueue > len)
    to_enqueue = len;
  // TODO what happens to the excess bytes?

  svm_fifo_enqueue_nowait (rx_fifo, to_enqueue, src);

  // Notify app
  app_wrk = app_worker_get_if_valid (app_session->app_wrk_index);
  if (PREDICT_TRUE (app_wrk != 0))
    app_worker_lock_and_send_event (app_wrk, app_session, SESSION_IO_EVT_RX);
  return 0;
}

static const quicly_stream_callbacks_t quic_stream_callbacks = {
  .on_destroy = quicly_streambuf_destroy,
  .on_send_shift = quicly_streambuf_egress_shift,
  .on_send_emit = quicly_streambuf_egress_emit,
  .on_send_stop = quic_on_stop_sending,
  .on_receive = quic_on_receive,
  .on_receive_reset = quic_on_receive_reset
};

static int
quic_on_stream_open (quicly_stream_open_cb * self, quicly_stream_t * stream)
{
  QUIC_DBG (2, "on_stream_open called");
  int ret;
  if ((ret =
       quicly_streambuf_create (stream, sizeof (quicly_streambuf_t))) != 0)
    {
      return ret;
    }
  stream->callbacks = &quic_stream_callbacks;
  return 0;
}

static quicly_stream_open_cb on_stream_open = { &quic_on_stream_open };

static void
quic_on_conn_close (quicly_closed_by_peer_cb * self, quicly_conn_t * conn,
		    int code, uint64_t frame_type,
		    const char *reason, size_t reason_len)
{
  QUIC_DBG (2, "connection closed, reason: %s", reason);
  u32 ctx_index = (u64) * quicly_get_data (conn);
  quic_connection_closed (ctx_index);
}

static quicly_closed_by_peer_cb on_closed_by_peer = { &quic_on_conn_close };


/*****************************************************************************
 * END QUICLY CALLBACKS
 *****************************************************************************/

/* single-entry session cache */
struct st_util_session_cache_t
{
  ptls_encrypt_ticket_t super;
  uint8_t id[32];
  ptls_iovec_t data;
};

static int
encrypt_ticket_cb (ptls_encrypt_ticket_t * _self, ptls_t * tls,
		   int is_encrypt, ptls_buffer_t * dst, ptls_iovec_t src)
{
  struct st_util_session_cache_t *self = (void *) _self;
  int ret;

  if (is_encrypt)
    {

      /* replace the cached entry along with a newly generated session id */
      free (self->data.base);
      if ((self->data.base = malloc (src.len)) == NULL)
	return PTLS_ERROR_NO_MEMORY;

      ptls_get_context (tls)->random_bytes (self->id, sizeof (self->id));
      memcpy (self->data.base, src.base, src.len);
      self->data.len = src.len;

      /* store the session id in buffer */
      if ((ret = ptls_buffer_reserve (dst, sizeof (self->id))) != 0)
	return ret;
      memcpy (dst->base + dst->off, self->id, sizeof (self->id));
      dst->off += sizeof (self->id);

    }
  else
    {

      /* check if session id is the one stored in cache */
      if (src.len != sizeof (self->id))
	return PTLS_ERROR_SESSION_NOT_FOUND;
      if (memcmp (self->id, src.base, sizeof (self->id)) != 0)
	return PTLS_ERROR_SESSION_NOT_FOUND;

      /* return the cached value */
      if ((ret = ptls_buffer_reserve (dst, self->data.len)) != 0)
	return ret;
      memcpy (dst->base + dst->off, self->data.base, self->data.len);
      dst->off += self->data.len;
    }

  return 0;
}

static struct st_util_session_cache_t sc = {
  .super = {
	    .cb = encrypt_ticket_cb,
	    },
};

/* *INDENT-OFF* */
static ptls_context_t quic_tlsctx = {
  .random_bytes = ptls_openssl_random_bytes,
  .get_time = &ptls_get_time,
  .key_exchanges = ptls_openssl_key_exchanges,
  .cipher_suites = ptls_openssl_cipher_suites,
  .certificates = {
    .list = NULL,
    .count = 0
  },
  .esni = NULL,
  .on_client_hello = NULL,
  .emit_certificate = NULL,
  .sign_certificate = NULL,
  .verify_certificate = NULL,
  .ticket_lifetime = 86400,
  .max_early_data_size = 8192,
  .hkdf_label_prefix__obsolete = NULL,
  .require_dhe_on_psk = 1,
  .encrypt_ticket = &sc.super,
};
/* *INDENT-ON* */

static int
ptls_compare_separator_line (const char *line, const char *begin_or_end,
			     const char *label)
{
  int ret = strncmp (line, "-----", 5);
  size_t text_index = 5;

  if (ret == 0)
    {
      size_t begin_or_end_length = strlen (begin_or_end);
      ret = strncmp (line + text_index, begin_or_end, begin_or_end_length);
      text_index += begin_or_end_length;
    }

  if (ret == 0)
    {
      ret = line[text_index] - ' ';
      text_index++;
    }

  if (ret == 0)
    {
      size_t label_length = strlen (label);
      ret = strncmp (line + text_index, label, label_length);
      text_index += label_length;
    }

  if (ret == 0)
    {
      ret = strncmp (line + text_index, "-----", 5);
    }

  return ret;
}

static int
ptls_get_bio_pem_object (BIO * bio, const char *label, ptls_buffer_t * buf)
{
  int ret = PTLS_ERROR_PEM_LABEL_NOT_FOUND;
  char line[256];
  ptls_base64_decode_state_t state;

  /* Get the label on a line by itself */
  while (BIO_gets (bio, line, 256))
    {
      if (ptls_compare_separator_line (line, "BEGIN", label) == 0)
	{
	  ret = 0;
	  ptls_base64_decode_init (&state);
	  break;
	}
    }
  /* Get the data in the buffer */
  while (ret == 0 && BIO_gets (bio, line, 256))
    {
      if (ptls_compare_separator_line (line, "END", label) == 0)
	{
	  if (state.status == PTLS_BASE64_DECODE_DONE
	      || (state.status == PTLS_BASE64_DECODE_IN_PROGRESS
		  && state.nbc == 0))
	    {
	      ret = 0;
	    }
	  else
	    {
	      ret = PTLS_ERROR_INCORRECT_BASE64;
	    }
	  break;
	}
      else
	{
	  ret = ptls_base64_decode (line, &state, buf);
	}
    }

  return ret;
}

int
ptls_load_bio_pem_objects (BIO * bio, const char *label, ptls_iovec_t * list,
			   size_t list_max, size_t * nb_objects)
{
  int ret = 0;
  size_t count = 0;

  *nb_objects = 0;

  if (ret == 0)
    {
      while (count < list_max)
	{
	  ptls_buffer_t buf;

	  ptls_buffer_init (&buf, "", 0);

	  ret = ptls_get_bio_pem_object (bio, label, &buf);

	  if (ret == 0)
	    {
	      if (buf.off > 0 && buf.is_allocated)
		{
		  list[count].base = buf.base;
		  list[count].len = buf.off;
		  count++;
		}
	      else
		{
		  ptls_buffer_dispose (&buf);
		}
	    }
	  else
	    {
	      ptls_buffer_dispose (&buf);
	      break;
	    }
	}
    }

  if (ret == PTLS_ERROR_PEM_LABEL_NOT_FOUND && count > 0)
    {
      ret = 0;
    }

  *nb_objects = count;

  return ret;
}

#define PTLS_MAX_CERTS_IN_CONTEXT 16

int
ptls_load_bio_certificates (ptls_context_t * ctx, BIO * bio)
{
  int ret = 0;

  ctx->certificates.list =
    (ptls_iovec_t *) malloc (PTLS_MAX_CERTS_IN_CONTEXT *
			     sizeof (ptls_iovec_t));

  if (ctx->certificates.list == NULL)
    {
      ret = PTLS_ERROR_NO_MEMORY;
    }
  else
    {
      ret =
	ptls_load_bio_pem_objects (bio, "CERTIFICATE", ctx->certificates.list,
				   PTLS_MAX_CERTS_IN_CONTEXT,
				   &ctx->certificates.count);
    }

  return ret;
}

static inline void
load_bio_certificate_chain (ptls_context_t * ctx, const char *cert_data)
{
  BIO *cert_bio;
  cert_bio = BIO_new_mem_buf (cert_data, -1);
  if (ptls_load_bio_certificates (ctx, cert_bio) != 0)
    {
      BIO_free (cert_bio);
      fprintf (stderr, "failed to load certificate:%s\n", strerror (errno));
      exit (1);
    }
  BIO_free (cert_bio);
}

static inline void
load_bio_private_key (ptls_context_t * ctx, const char *pk_data)
{
  static ptls_openssl_sign_certificate_t sc;
  EVP_PKEY *pkey;
  BIO *key_bio;

  key_bio = BIO_new_mem_buf (pk_data, -1);
  pkey = PEM_read_bio_PrivateKey (key_bio, NULL, NULL, NULL);
  BIO_free (key_bio);

  if (pkey == NULL)
    {
      fprintf (stderr, "failed to read private key from app configuration\n");
      exit (1);
    }

  ptls_openssl_init_sign_certificate (&sc, pkey);
  EVP_PKEY_free (pkey);

  ctx->sign_certificate = &sc.super;
}

static void
quic_connection_closed (u32 ctx_index)
{
  QUIC_DBG (2, "QUIC connection closed");
  quic_ctx_t *ctx;

  ctx = quic_ctx_get (ctx_index);
  // TODO if connection is not established, just delete the session

  // Do not try to send anything anymore
  ctx->stream = NULL;
  quicly_free (ctx->c_quic_ctx_id.conn);
  ctx->c_quic_ctx_id.conn = NULL;
  session_transport_closing_notify (&ctx->connection);
}

static int64_t
quic_get_time (quicly_now_cb * self)
{
  // TODO read value set by set_time_now?
  // (needs to change it not to call this function)
  vlib_main_t *vlib_main = vlib_get_main ();
  f64 time = vlib_time_now (vlib_main);
  return (int64_t) (time * 1000.f);
}
quicly_now_cb quicly_vpp_now_cb = { quic_get_time };

static void
allocate_quicly_ctx (application_t * app, u8 is_client)
{
  QUIC_DBG (2, "Called allocate_quicly_ctx");
  struct
  {
    quicly_context_t _;
    char cid_key[17];
  } *ctx_data;
  quicly_context_t *quicly_ctx;
  char *cid_key;

  ctx_data = malloc (sizeof (*ctx_data));
  quicly_ctx = &ctx_data->_;
  app->quicly_ctx = (u64 *) quicly_ctx;
  memcpy (quicly_ctx, &quicly_default_context, sizeof (quicly_context_t));

  quicly_ctx->tls = &quic_tlsctx;
  quicly_ctx->stream_open = &on_stream_open;
  quicly_ctx->closed_by_peer = &on_closed_by_peer;
  quicly_ctx->now = &quicly_vpp_now_cb;

  quicly_amend_ptls_context (quicly_ctx->tls);

  quicly_ctx->event_log.mask = INT64_MAX;
  quicly_ctx->event_log.cb = quicly_new_default_event_log_cb (stderr);

  quicly_ctx->transport_params.max_data = QUIC_INT_MAX;
  quicly_ctx->transport_params.max_streams_uni = QUIC_INT_MAX;
  quicly_ctx->transport_params.max_streams_bidi = QUIC_INT_MAX;
  quicly_ctx->transport_params.max_stream_data.bidi_local = QUIC_INT_MAX;
  quicly_ctx->transport_params.max_stream_data.bidi_remote = QUIC_INT_MAX;
  quicly_ctx->transport_params.max_stream_data.uni = QUIC_INT_MAX;

  if (!is_client)
    {
      load_bio_private_key (quicly_ctx->tls, (char *) app->tls_key);
      load_bio_certificate_chain (quicly_ctx->tls, (char *) app->tls_cert);
      cid_key = ctx_data->cid_key;
      quicly_ctx->tls->random_bytes (cid_key, 16);
      cid_key[16] = 0;
      quicly_ctx->encrypt_cid =
	quicly_new_default_encrypt_cid_cb (&ptls_openssl_bfecb,
					   &ptls_openssl_sha256,
					   ptls_iovec_init (cid_key,
							    strlen
							    (cid_key)));
      quicly_ctx->decrypt_cid =
	quicly_new_default_decrypt_cid_cb (&ptls_openssl_bfecb,
					   &ptls_openssl_sha256,
					   ptls_iovec_init (cid_key,
							    strlen
							    (cid_key)));
    }
}


/*****************************************************************************
 * BEGIN TIMERS HANDLING
 *****************************************************************************/

static u32
quic_set_time_now (u32 thread_index)
{
  quic_main.wrk_ctx[thread_index].time_now = quic_get_time (NULL);
  return quic_main.wrk_ctx[thread_index].time_now;
}

static void
quic_timer_expired (u32 conn_index)
{
  quic_ctx_t *ctx;
  QUIC_DBG (2, "Timer expired for conn %u at %ld", conn_index,
	    quic_get_time (NULL));
  ctx = quic_ctx_get (conn_index);
  ctx->c_quic_ctx_id.timer_handle = QUIC_TIMER_HANDLE_INVALID;
  if (quic_send_packets (ctx))
    {
      quic_connection_closed (conn_index);
    }
}

static void
quic_update_timer (quic_ctx_t * ctx)
{
  tw_timer_wheel_1t_3w_1024sl_ov_t *tw;
  int64_t next_timeout;

  // This timeout is in ms which is the unit of our timer
  next_timeout = quicly_get_first_timeout (ctx->c_quic_ctx_id.conn);
  tw = &quic_main.wrk_ctx[vlib_get_thread_index ()].timer_wheel;
  f64 next_timeout_f = ((f64) next_timeout) / 1000.f;

  clib_warning ("Timer set to %ld (%lf)", next_timeout, next_timeout_f);

  if (ctx->c_quic_ctx_id.timer_handle == QUIC_TIMER_HANDLE_INVALID)
    {
      if (next_timeout == INT64_MAX)
	return;
      ctx->c_quic_ctx_id.timer_handle =
	tw_timer_start_1t_3w_1024sl_ov (tw, ctx->c_c_index, 0,
					next_timeout_f);
    }
  else
    {
      if (next_timeout == INT64_MAX)
	{
	  tw_timer_stop_1t_3w_1024sl_ov (tw, ctx->c_quic_ctx_id.timer_handle);
	  ctx->c_quic_ctx_id.timer_handle = QUIC_TIMER_HANDLE_INVALID;
	}
      else
	tw_timer_update_1t_3w_1024sl_ov (tw, ctx->c_quic_ctx_id.timer_handle,
					 next_timeout_f);
    }
}

static void
quic_expired_timers_dispatch (u32 * expired_timers)
{
  int i;

  for (i = 0; i < vec_len (expired_timers); i++)
    {
      quic_timer_expired (expired_timers[i]);
    }
}


/*****************************************************************************
 * END TIMERS HANDLING
 *
 * BEGIN TRANSPORT PROTO FUNCTIONS
 *****************************************************************************/

int
quic_connect (transport_endpoint_cfg_t * tep)
{
  QUIC_DBG (2, "Called quic_connect");
  vnet_connect_args_t _cargs = { {}, }, *cargs = &_cargs;
  session_endpoint_cfg_t *sep;
  quic_main_t *qm = &quic_main;
  quic_ctx_t *ctx;
  app_worker_t *app_wrk;
  application_t *app;
  u32 ctx_index;
  int error;

  sep = (session_endpoint_cfg_t *) tep;
  ctx_index = quic_ctx_half_open_alloc ();
  ctx = quic_ctx_half_open_get (ctx_index);
  ctx->c_quic_ctx_id.parent_app_wrk_idx = sep->app_wrk_index;
  ctx->c_s_index = 0xFAFAFAFA;
  ctx->c_quic_ctx_id.udp_is_ip4 = sep->is_ip4;
  ctx->c_quic_ctx_id.timer_handle = QUIC_TIMER_HANDLE_INVALID;
  ctx->c_quic_ctx_id.conn_state = QUIC_CONN_STATE_HANDSHAKE;
  ctx->client_opaque = sep->opaque;
  if (sep->hostname)
    {
      ctx->srv_hostname = format (0, "%v", sep->hostname);
      vec_terminate_c_string (ctx->srv_hostname);
    }
  else
    {
      // needed by quic for crypto + determining client / server
      ctx->srv_hostname =
	format (0, "%U", format_ip46_address, &sep->ip, sep->is_ip4);
    }

  quic_ctx_half_open_reader_unlock ();

  clib_memcpy (&cargs->sep, sep, sizeof (session_endpoint_cfg_t));
  cargs->sep.transport_proto = TRANSPORT_PROTO_UDP;
  cargs->app_index = qm->app_index;
  cargs->api_context = ctx_index;

  app_wrk = app_worker_get (sep->app_wrk_index);
  app = application_get (app_wrk->app_index);
  ctx->c_quic_ctx_id.parent_app_id = app_wrk->app_index;
  cargs->sep_ext.ns_index = app->ns_index;

  allocate_quicly_ctx (app, 1 /* is client */ );

  if ((error = vnet_connect (cargs)))
    return error;

  QUIC_DBG (1, "New connect request %u", ctx_index);
  return 0;
}

static void
quic_disconnect (u32 ctx_index, u32 thread_index)
{
  QUIC_DBG (2, "Called quic_disconnect");
  tw_timer_wheel_1t_3w_1024sl_ov_t *tw;
  quic_ctx_t *ctx;

  QUIC_DBG (1, "Disconnecting %x", ctx_index);

  ctx = quic_ctx_get (ctx_index);
  if (ctx->c_quic_ctx_id.timer_handle != QUIC_TIMER_HANDLE_INVALID)
    {
      tw = &quic_main.wrk_ctx[vlib_get_thread_index ()].timer_wheel;
      tw_timer_stop_1t_3w_1024sl_ov (tw, ctx->c_quic_ctx_id.timer_handle);
    }
  quic_disconnect_transport (ctx);
  // This removes the session from the lookup table and frees it.
  session_transport_delete_notify (&ctx->connection);
  quic_ctx_free (ctx);
}

u32
quic_start_listen (u32 app_listen_session_index, transport_endpoint_t * tep)
{
  QUIC_DBG (2, "Called quic_start_listen");
  vnet_listen_args_t _bargs, *args = &_bargs;
  quic_main_t *qm = &quic_main;
  session_handle_t udp_handle;
  session_endpoint_cfg_t *sep;
  session_t *quic_listen_session, *app_listen_session;
  app_worker_t *app_wrk;
  application_t *app;
  quic_ctx_t *lctx;
  u32 lctx_index;
  app_listener_t *app_listener;

  sep = (session_endpoint_cfg_t *) tep;
  app_wrk = app_worker_get (sep->app_wrk_index);
  app = application_get (app_wrk->app_index);

  allocate_quicly_ctx (app, 0 /* is_client */ );

  sep->transport_proto = TRANSPORT_PROTO_UDP;
  memset (args, 0, sizeof (*args));
  args->app_index = qm->app_index;
  args->sep_ext = *sep;
  args->sep_ext.ns_index = app->ns_index;
  if (vnet_listen (args))
    return -1;

  lctx_index = quic_ctx_alloc ();	// listener
  udp_handle = args->handle;
  app_listener = app_listener_get_w_handle (udp_handle);
  quic_listen_session = app_listener_get_session (app_listener);
  quic_listen_session->opaque = lctx_index;

  app_listen_session = listen_session_get (app_listen_session_index);

  lctx = quic_ctx_get (lctx_index);	// listener
  lctx->is_listener = 1;
  lctx->c_quic_ctx_id.parent_app_wrk_idx = sep->app_wrk_index;
  lctx->c_quic_ctx_id.parent_app_id = app_wrk->app_index;
  lctx->c_quic_ctx_id.quic_session = udp_handle;
  lctx->c_quic_ctx_id.app_session =
    listen_session_get_handle (app_listen_session);
  lctx->c_quic_ctx_id.udp_is_ip4 = sep->is_ip4;

  QUIC_DBG (1, "Started listening %d", lctx_index);
  return lctx_index;
}

u32
quic_stop_listen (u32 lctx_index)
{
  QUIC_DBG (2, "Called quic_stop_listen");
  quic_ctx_t *lctx;

  lctx = quic_ctx_get (lctx_index);	// listener
  vnet_unlisten_args_t a = {
    .handle = lctx->c_quic_ctx_id.quic_session,
    .app_index = quic_main.app_index,
    .wrk_map_index = 0		/* default wrk */
  };
  if (vnet_unlisten (&a))
    clib_warning ("unlisten errored");

  // TODO: crypto state cleanup

  quic_ctx_free (lctx);		// listener
  return 0;
}

transport_connection_t *
quic_connection_get (u32 ctx_index, u32 thread_index)
{
  QUIC_DBG (2, "Called quic_connection_get");
  quic_ctx_t *ctx;
  ctx = quic_ctx_get_w_thread (ctx_index, thread_index);
  return &ctx->connection;
}

transport_connection_t *
quic_listener_get (u32 listener_index)
{
  QUIC_DBG (2, "Called quic_listener_get");
  quic_ctx_t *ctx;
  ctx = quic_ctx_get (listener_index);
  return &ctx->connection;
}

static void
quic_update_time (f64 now, u8 thread_index)
{
  tw_timer_wheel_1t_3w_1024sl_ov_t *tw;

  tw = &quic_main.wrk_ctx[thread_index].timer_wheel;
  quic_set_time_now (thread_index);
  tw_timer_expire_timers_1t_3w_1024sl_ov (tw, now);
}

static u8 *
format_quic_connection (u8 * s, va_list * args)
{
  s = format (s, "[QUIC] connection");
  return s;
}

static u8 *
format_quic_half_open (u8 * s, va_list * args)
{
  u32 qc_index = va_arg (*args, u32);
  quic_ctx_t *ctx = quic_ctx_half_open_get (qc_index);
  s = format (s, "[QUIC] half-open app %u", ctx->c_quic_ctx_id.parent_app_id);
  quic_ctx_half_open_reader_unlock ();
  return s;
}

// TODO improve
static u8 *
format_quic_listener (u8 * s, va_list * args)
{
  s = format (s, "[QUIC] listener");
  return s;
}

/*****************************************************************************
 * END TRANSPORT PROTO FUNCTIONS
 *
 * START SESSION CALLBACKS
 * Called from UDP layer
 *****************************************************************************/

static inline void
quic_build_sockaddr (struct sockaddr *sa, socklen_t * salen,
		     ip46_address_t * addr, u16 port, u8 is_ip4)
{
  if (is_ip4)
    {
      struct sockaddr_in *sa4 = (struct sockaddr_in *) sa;
      sa4->sin_family = AF_INET;
      sa4->sin_port = port;
      sa4->sin_addr.s_addr = addr->ip4.as_u32;
      *salen = sizeof (struct sockaddr_in);
    }
  else
    {
      struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) sa;
      sa6->sin6_family = AF_INET6;
      sa6->sin6_port = port;
      clib_memcpy (&sa6->sin6_addr, &addr->ip6, 16);
      *salen = sizeof (struct sockaddr_in6);
    }
}

static int
quic_delayed_notify_app_connected (void *ctx_index)
{
  QUIC_DBG (1, "quic_notify_app_connected");
  session_t *app_session;
  app_worker_t *app_wrk;
  quic_ctx_t *ctx;
  ctx = quic_ctx_get ((u32) (u64) ctx_index);

  app_wrk = app_worker_get_if_valid (ctx->c_quic_ctx_id.parent_app_wrk_idx);
  if (!app_wrk)
    {
      quic_disconnect_transport (ctx);
      return -1;
    }

  app_session = session_alloc (ctx->c_thread_index);
  QUIC_DBG (1, "Created app_session, id %u", app_session->session_index);
  ctx->c_s_index = app_session->session_index;
  app_session->app_wrk_index = ctx->c_quic_ctx_id.parent_app_wrk_idx;
  app_session->connection_index = ctx->c_c_index;
  app_session->session_type =
    session_type_from_proto_and_ip (TRANSPORT_PROTO_QUIC,
				    ctx->c_quic_ctx_id.udp_is_ip4);

  if (app_worker_init_connected (app_wrk, app_session))	// TODO dont allocate fifos
    {
      quic_disconnect (ctx->c_c_index, vlib_get_thread_index ());
      return app_worker_connect_notify (app_wrk, NULL, ctx->client_opaque);
    }

  app_session->session_state = SESSION_STATE_CONNECTING;
  if (app_worker_connect_notify (app_wrk, app_session, ctx->client_opaque))
    {
      QUIC_DBG (1, "failed to notify app");
      quic_disconnect (ctx->c_c_index, vlib_get_thread_index ());
      return -1;
    }

  ctx->c_quic_ctx_id.app_session = session_handle (app_session);
  app_session->session_state = SESSION_STATE_LISTENING;
  session_lookup_add_connection (&ctx->connection,
				 session_handle (app_session));

  return 0;
}

int
quic_session_connected_callback (u32 quic_app_index, u32 ho_ctx_idx,
				 session_t * s, u8 is_fail)
{
  QUIC_DBG (2, "Called quic_session_connected_callback");
  // This should always be called before quic_connect returns since UDP always
  // connects instantly.
  struct sockaddr_in6 sa6;
  struct sockaddr *sa = (struct sockaddr *) &sa6;
  socklen_t salen;
  transport_connection_t *tc;
  quic_ctx_t *ho_ctx, *ctx;
  u32 ctx_index;
  int ret;
  application_t *app;
  app_worker_t *app_wrk;

  ho_ctx = quic_ctx_half_open_get (ho_ctx_idx);
  if (is_fail)
    {
      u32 api_context;
      int rv = 0;

      app_wrk =
	app_worker_get_if_valid (ho_ctx->c_quic_ctx_id.parent_app_wrk_idx);
      if (app_wrk)
	{
	  api_context = ho_ctx->c_s_index;
	  app_worker_connect_notify (app_wrk, 0, api_context);
	}
      quic_ctx_half_open_reader_unlock ();
      quic_ctx_half_open_free (ho_ctx_idx);
      return rv;
    }

  app_wrk =
    app_worker_get_if_valid (ho_ctx->c_quic_ctx_id.parent_app_wrk_idx);
  if (!app_wrk)
    {
      QUIC_DBG (1, "Appwrk not found");
      return -1;
    }
  app = application_get (app_wrk->app_index);

  ctx_index = quic_ctx_alloc ();
  ctx = quic_ctx_get (ctx_index);
  clib_memcpy (ctx, ho_ctx, sizeof (*ctx));
  quic_ctx_half_open_reader_unlock ();	// TODO: this is a race
  quic_ctx_half_open_free (ho_ctx_idx);

  ctx->c_thread_index = vlib_get_thread_index ();
  ctx->c_c_index = ctx_index;

  QUIC_DBG (1, "Quic connect for returned %u. New connection [%u]%x",
	    is_fail, vlib_get_thread_index (), (ctx) ? ctx_index : ~0);

  ctx->c_quic_ctx_id.quic_session = session_handle (s);
  s->opaque = ctx_index;
  s->session_state = SESSION_STATE_READY;

  // Init QUIC lib connection
  // Generate required sockaddr & salen
  tc = session_get_transport (s);
  quic_build_sockaddr (sa, &salen, &tc->rmt_ip, tc->rmt_port, tc->is_ip4);

  ret =
    quicly_connect (&ctx->c_quic_ctx_id.conn,
		    (quicly_context_t *) app->quicly_ctx,
		    (char *) ctx->srv_hostname, sa, salen,
		    &quic_main.next_cid, &quic_main.hs_properties, NULL);
  ++quic_main.next_cid.master_id;
  // Save context handle in quicly connection
  *quicly_get_data (ctx->c_quic_ctx_id.conn) = (void *) (u64) ctx_index;
  assert (ret == 0);

  if (quic_send_packets (ctx))
    {
      quic_connection_closed (ctx_index);
    }
  return ret;
}

void
quic_session_disconnect_callback (session_t * s)
{
  clib_warning ("UDP session disconnected???");
}

void
quic_session_reset_callback (session_t * s)
{
  clib_warning ("UDP session reset???");
}

int
quic_session_accepted_callback (session_t * s)
{
  /* never called */
  return 0;
}

static int
quic_add_segment_callback (u32 client_index, u64 seg_handle)
{
  QUIC_DBG (2, "Called quic_add_segment_callback");
  QUIC_DBG (2, "NOT IMPLEMENTED");
  /* No-op for builtin */
  return 0;
}

static int
quic_del_segment_callback (u32 client_index, u64 seg_handle)
{
  QUIC_DBG (2, "Called quic_del_segment_callback");
  QUIC_DBG (2, "NOT IMPLEMENTED");
  /* No-op for builtin */
  return 0;
}

int
quic_add_vpp_q_builtin_tx_evt (session_t * s)
{
  if (svm_fifo_set_event (s->tx_fifo))
    session_send_io_evt_to_thread_custom (s, s->thread_index,
					  FIFO_EVENT_BUILTIN_TX);
  return 0;
}

void
quic_open_stream_if_ready (quic_ctx_t * ctx)
{
  quicly_conn_t *conn = ctx->c_quic_ctx_id.conn;
  if (ctx->stream)
    {
      QUIC_DBG (2, "----------- > FOUND Stream id %d",
		ctx->stream->stream_id);
      QUIC_DBG (2, "----------- > FOUND Stream is_open %d",
		ctx->stream->sendstate.is_open);
      return;
    }
  if (quicly_connection_is_ready (conn))
    assert (!quicly_open_stream (conn, &ctx->stream, 0));
  QUIC_DBG (2, "Stream id %d", ctx->stream->stream_id);
  QUIC_DBG (2, "Stream is_open %d", ctx->stream->sendstate.is_open);
}

int
quic_custom_tx_callback (void *session)
{
  QUIC_DBG (2, "Called quic_custom_tx_callback");
  session_t *app_session = (session_t *) session;
  quic_ctx_t *ctx;
  svm_fifo_t *f;
  u32 deq_max;
  u8 *data;

  if (PREDICT_FALSE
      (app_session->session_state >= SESSION_STATE_TRANSPORT_CLOSING))
    return 0;
  ctx = quic_ctx_get (app_session->connection_index);
  quic_open_stream_if_ready (ctx);
  if (!ctx->stream)
    {
      quic_add_vpp_q_builtin_tx_evt (app_session);
      return 0;
    }

  f = app_session->tx_fifo;
  deq_max = svm_fifo_max_dequeue (f);
  if (!deq_max)
    return 0;

  data = svm_fifo_head (f);
  if (quicly_streambuf_egress_write (ctx->stream, data, deq_max))
    {
      assert (0);
      return 0;
    }
  QUIC_DBG (2, "Sent %u bytes", deq_max);
  svm_fifo_dequeue_drop (f, deq_max);
  if (quic_send_packets (ctx))
    {
      quic_connection_closed (ctx->c_c_index);
    }
  return 0;
}

int
quic_find_packet_ctx (quic_ctx_t ** ctx, quicly_conn_t ** conn,
		      struct sockaddr *sa, socklen_t salen,
		      quicly_decoded_packet_t packet)
{
  quic_ctx_t *ctx_;
  quicly_conn_t *conn_;
  /* *INDENT-OFF* */
  pool_foreach (ctx_, quic_main.ctx_pool[vlib_get_thread_index()],
  ({
    conn_ = ctx_->c_quic_ctx_id.conn;
    if (conn_ && !ctx_->is_listener)
      {
        if (quicly_is_destination(conn_, sa, salen, &packet))
          {
            *conn = conn_;
            *ctx = ctx_;
            QUIC_DBG (2, "connection_found");
            return 0;
          }
      }
  }));
  /* *INDENT-ON* */
  return 0;
}

static int
quic_receive (quic_ctx_t * ctx, quicly_conn_t * conn,
	      quicly_decoded_packet_t packet)
{
  quicly_receive (conn, &packet);
  // Conn may be set to null if the connection is terminated
  if (ctx->c_quic_ctx_id.conn
      && ctx->c_quic_ctx_id.conn_state == QUIC_CONN_STATE_HANDSHAKE)
    {
      if (quicly_connection_is_ready (conn))
	{
	  ctx->c_quic_ctx_id.conn_state = QUIC_CONN_STATE_READY;
	  if (quicly_is_client (conn))
	    session_send_rpc_evt_to_thread_force (vlib_get_thread_index (),
						  &quic_delayed_notify_app_connected,
						  (void *) (u64)
						  ctx->c_c_index);
	}
    }
  if (quic_send_packets (ctx))
    {
      quic_connection_closed (ctx->c_c_index);
    }
  return 0;
}

static int
quic_delayed_create_app_session (void *ctx_index)
{
  quic_ctx_t *lctx, *ctx;
  session_t *app_session, *app_listen_session;
  app_worker_t *app_wrk;
  int rv;

  ctx = quic_ctx_get ((u32) (u64) ctx_index);
  app_session = session_alloc (ctx->c_thread_index);
  app_session->session_state = SESSION_STATE_LISTENING;
  ctx->c_s_index = app_session->session_index;

  lctx = quic_ctx_get (ctx->c_quic_ctx_id.listener_ctx_id);

  app_listen_session =
    listen_session_get_from_handle (lctx->c_quic_ctx_id.app_session);
  app_session->app_wrk_index = lctx->c_quic_ctx_id.parent_app_wrk_idx;
  app_session->connection_index = ctx->c_c_index;
  app_session->session_type = app_listen_session->session_type;
  app_session->listener_index = app_listen_session->session_index;
  app_session->app_index = quic_main.app_index;

  // TODO: don't alloc fifos when we don't transfer data on this session
  if ((rv = app_worker_init_accepted (app_session)))
    {
      QUIC_DBG (1, "failed to allocate fifos");
      session_free (app_session);
      return rv;
    }
  ctx->c_quic_ctx_id.app_session = session_handle (app_session);
  ctx->c_quic_ctx_id.parent_app_id = lctx->c_quic_ctx_id.parent_app_id;
  ctx->c_quic_ctx_id.udp_is_ip4 = lctx->c_quic_ctx_id.udp_is_ip4;
  ctx->c_quic_ctx_id.parent_app_wrk_idx = app_session->app_wrk_index;
  session_lookup_add_connection (&ctx->connection,
				 session_handle (app_session));
  app_wrk = app_worker_get (app_session->app_wrk_index);
  rv = app_worker_accept_notify (app_wrk, app_session);
  if (rv)
    {
      QUIC_DBG (1, "failed to notify accept worker app");
      return rv;
    }
  return 0;
}

static int
quic_create_connection (quicly_context_t * quicly_ctx,
			u64 quic_session_handle, u32 lctx_index,
			quicly_conn_t * conn, struct sockaddr *sa,
			socklen_t salen, quicly_decoded_packet_t packet)
{
  quic_ctx_t *ctx;
  u32 ctx_index;

  /* new connection, accept and create context if packet is valid */
  // TODO: check if socket is actually listening?
  QUIC_DBG (2, "New connection created");
  if (quicly_accept (&conn, quicly_ctx, sa, salen,
		     &packet, ptls_iovec_init (NULL, 0),
		     &quic_main.next_cid, NULL) != 0)
    {
      // Invalid packet, pass
      assert (conn == NULL);
      QUIC_DBG (2, "Accept failed");
      return 0;
    }
  assert (conn != NULL);

  ++quic_main.next_cid.master_id;
  // Create context
  ctx_index = quic_ctx_alloc ();
  ctx = quic_ctx_get (ctx_index);
  // Save ctx handle in quicly connection
  *quicly_get_data (conn) = (void *) (u64) ctx_index;

  ctx->c_thread_index = vlib_get_thread_index ();
  ctx->c_c_index = ctx_index;
  ctx->c_quic_ctx_id.quic_session = quic_session_handle;
  ctx->c_quic_ctx_id.listener_ctx_id = lctx_index;
  ctx->c_quic_ctx_id.timer_handle = QUIC_TIMER_HANDLE_INVALID;
  ctx->c_quic_ctx_id.conn = conn;

  session_send_rpc_evt_to_thread_force (vlib_get_thread_index (),
					&quic_delayed_create_app_session,
					(void *) (u64) ctx_index);
  if (quic_send_packets (ctx))
    {
      quic_connection_closed (ctx_index);
    }
  return 0;
}

static int
quic_reset_connection (quicly_context_t * quicly_ctx, u64 quic_session_handle,
		       struct sockaddr *sa, socklen_t salen,
		       quicly_decoded_packet_t packet)
{
  /* short header packet; potentially a dead connection. No need to check the length of the incoming packet,
   * because loop is prevented by authenticating the CID (by checking node_id and thread_id). If the peer is also
   * sending a reset, then the next CID is highly likely to contain a non-authenticating CID, ... */
  QUIC_DBG (2, "Sending stateless reset");
  quicly_datagram_t *dgram;
  session_t *quic_session;
  if (packet.cid.dest.plaintext.node_id == 0
      && packet.cid.dest.plaintext.thread_id == 0)
    {
      dgram = quicly_send_stateless_reset (quicly_ctx, sa, salen,
					   &packet.cid.dest.plaintext);
      quic_session = session_get_from_handle (quic_session_handle);
      if (quic_send_datagram (quic_session, dgram))	// TODO : missing event on fifo
	QUIC_DBG (2, "Send reset failed");
    }
  return 0;
}

int
quic_app_rx_callback (session_t * quic_session)
{
  // Read data from UDP rx_fifo and pass it to the quicly conn.
  QUIC_DBG (2, "Called quic_app_rx_callback");

  quicly_decoded_packet_t packet;
  session_dgram_hdr_t ph;
  application_t *app;
  quicly_conn_t *conn = NULL;
  quic_ctx_t *lctx, *ctx = NULL;
  svm_fifo_t *f;
  size_t plen;
  struct sockaddr_in6 sa6;
  struct sockaddr *sa = (struct sockaddr *) &sa6;
  socklen_t salen;
  u32 max_deq, len;
  u8 *data;
  u32 lctx_index = quic_session->opaque;
  u64 quic_session_handle = session_handle (quic_session);

  f = quic_session->rx_fifo;

  do
    {
      conn = NULL;
      max_deq = svm_fifo_max_dequeue (f);
      if (max_deq < sizeof (session_dgram_hdr_t))
	{
	  svm_fifo_unset_event (f);
	  return 0;
	}
      QUIC_DBG (2, "Processing one packet at %ld", quic_get_time (NULL));

      svm_fifo_unset_event (f);
      svm_fifo_peek (f, 0, sizeof (ph), (u8 *) & ph);
      ASSERT (ph.data_length >= ph.data_offset);
      len = ph.data_length - ph.data_offset;

      quic_build_sockaddr (sa, &salen, &ph.rmt_ip, ph.rmt_port, ph.is_ip4);

      // Quicly can read len bytes from the fifo at offset:
      // ph.data_offset + SESSION_CONN_HDR_LEN
      data = svm_fifo_head (f) + ph.data_offset + SESSION_CONN_HDR_LEN;

      lctx = quic_ctx_get (lctx_index);
      app = application_get (lctx->c_quic_ctx_id.parent_app_id);

      plen =
	quicly_decode_packet ((quicly_context_t *) app->quicly_ctx, &packet,
			      data, len);
      if (plen != SIZE_MAX)
	{
	  quic_find_packet_ctx (&ctx, &conn, sa, salen, packet);
	  if (conn != NULL)
	    quic_receive (ctx, conn, packet);
	  else if (QUICLY_PACKET_IS_LONG_HEADER (packet.octets.base[0]))
	    quic_create_connection ((quicly_context_t *) app->quicly_ctx,
				    quic_session_handle, lctx_index, conn,
				    sa, salen, packet);
	  else if (((quicly_context_t *) app->quicly_ctx)->encrypt_cid)
	    quic_reset_connection ((quicly_context_t *) app->quicly_ctx,
				   quic_session_handle, sa, salen, packet);
	}
      svm_fifo_dequeue_drop (f,
			     ph.data_length + ph.data_offset +
			     SESSION_CONN_HDR_LEN);
    }
  while (1);
  return 0;
}

/*****************************************************************************
 * END TRANSPORT PROTO FUNCTIONS
*****************************************************************************/

/* *INDENT-OFF* */
static session_cb_vft_t quic_app_cb_vft = {
  .session_accept_callback = quic_session_accepted_callback,
  .session_disconnect_callback = quic_session_disconnect_callback,
  .session_connected_callback = quic_session_connected_callback,
  .session_reset_callback = quic_session_reset_callback,
  .add_segment_callback = quic_add_segment_callback,
  .del_segment_callback = quic_del_segment_callback,
  .builtin_app_rx_callback = quic_app_rx_callback,
};

const static transport_proto_vft_t quic_proto = {
  .connect = quic_connect,
  .close = quic_disconnect,
  .start_listen = quic_start_listen,
  .stop_listen = quic_stop_listen,
  .get_connection = quic_connection_get,
  .get_listener = quic_listener_get,
  .update_time = quic_update_time,
  .custom_tx = quic_custom_tx_callback,
  .tx_type = TRANSPORT_TX_INTERNAL,
  .service_type = TRANSPORT_SERVICE_APP,
  .format_connection = format_quic_connection,
  .format_half_open = format_quic_half_open,
  .format_listener = format_quic_listener,
};
/* *INDENT-ON* */

static clib_error_t *
quic_init (vlib_main_t * vm)
{
  QUIC_DBG (2, "Called quic_init");
  u32 add_segment_size = (4096ULL << 20) - 1, segment_size = 512 << 20;
  vlib_thread_main_t *vtm = vlib_get_thread_main ();
  vnet_app_attach_args_t _a, *a = &_a;
  u64 options[APP_OPTIONS_N_OPTIONS];
  quic_main_t *qm = &quic_main;
  u32 fifo_size = 64 << 10;
  u32 num_threads;

  num_threads = 1 /* main thread */  + vtm->n_threads;

  memset (a, 0, sizeof (*a));
  memset (options, 0, sizeof (options));

  a->session_cb_vft = &quic_app_cb_vft;
  a->api_client_index = APP_INVALID_INDEX;
  a->options = options;
  a->name = format (0, "quic");
  a->options[APP_OPTIONS_SEGMENT_SIZE] = segment_size;
  a->options[APP_OPTIONS_ADD_SEGMENT_SIZE] = add_segment_size;
  a->options[APP_OPTIONS_RX_FIFO_SIZE] = fifo_size;
  a->options[APP_OPTIONS_TX_FIFO_SIZE] = fifo_size;
  a->options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;
  a->options[APP_OPTIONS_FLAGS] |= APP_OPTIONS_FLAGS_USE_GLOBAL_SCOPE;
  a->options[APP_OPTIONS_FLAGS] |= APP_OPTIONS_FLAGS_IS_TRANSPORT_APP;

  if (vnet_application_attach (a))
    {
      clib_warning ("failed to attach quic app");
      return clib_error_return (0, "failed to attach quic app");
    }

  vec_validate (qm->ctx_pool, num_threads - 1);
  vec_validate (qm->wrk_ctx, num_threads - 1);
  // Timers, one per thread.
  tw_timer_wheel_1t_3w_1024sl_ov_t *tw;
  /* *INDENT-OFF* */
  foreach_vlib_main (({
    tw = &qm->wrk_ctx[ii].timer_wheel;
    tw_timer_wheel_init_1t_3w_1024sl_ov (tw, quic_expired_timers_dispatch,
                                         10e-3 /* timer period 1ms */ , ~0);
    tw->last_run_time = vlib_time_now (this_vlib_main);
  }));
  /* *INDENT-ON* */

  if (!qm->ca_cert_path)
    qm->ca_cert_path = QUIC_DEFAULT_CA_CERT_PATH;

  qm->app_index = a->app_index;
  clib_rwlock_init (&qm->half_open_rwlock);
  qm->tstamp_ticks_per_clock = vm->clib_time.seconds_per_clock
    / QUIC_TSTAMP_RESOLUTION;

  transport_register_protocol (TRANSPORT_PROTO_QUIC, &quic_proto,
			       FIB_PROTOCOL_IP4, ~0);
  transport_register_protocol (TRANSPORT_PROTO_QUIC, &quic_proto,
			       FIB_PROTOCOL_IP6, ~0);

  vec_free (a->name);
  return 0;
}

quic_main_t *
vnet_quic_get_main (void)
{
  return &quic_main;
}

VLIB_INIT_FUNCTION (quic_init);

/* *INDENT-OFF* */
VLIB_PLUGIN_REGISTER () =
{
  .version = VPP_BUILD_VER,
  .description = "Quic transport protocol",
};
/* *INDENT-ON* */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */
