tls: make tls engines pluggable

- add infra for pluggable tls "engines"
- makes mbedtls specific code a plugin

Change-Id: I2c5b099e2b69d2be0038e3ef02b208ff907727e7
Signed-off-by: Florin Coras <fcoras@cisco.com>

2 files changed, 940 insertions, 0 deletions

diff --git a/src/vnet/tls/tls.c b/src/vnet/tls/tls.c
new file mode 100644
index 00000000000..65900c8b2cf
--- /dev/null
+++ b/src/vnet/tls/tls.c
@@ -0,0 +1,813 @@
+/*
+ * Copyright (c) 2018 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 <vnet/session/application_interface.h>
+#include <vppinfra/lock.h>
+#include <vnet/tls/tls.h>
+
+static tls_main_t tls_main;
+static tls_engine_vft_t *tls_vfts;
+
+#define DEFAULT_ENGINE 0
+void tls_disconnect (u32 ctx_index, u32 thread_index);
+
+int
+tls_add_vpp_q_evt (svm_fifo_t * f, u8 evt_type)
+{
+  session_fifo_event_t evt;
+  svm_queue_t *q;
+
+  if (svm_fifo_set_event (f))
+    {
+      evt.fifo = f;
+      evt.event_type = evt_type;
+
+      q = session_manager_get_vpp_event_queue (f->master_thread_index);
+      if (PREDICT_TRUE (q->cursize < q->maxsize))
+	{
+	  svm_queue_add (q, (u8 *) & evt, 0 /* do wait for mutex */ );
+	}
+      else
+	{
+	  clib_warning ("vpp's evt q full");
+	  return -1;
+	}
+    }
+  return 0;
+}
+
+static inline int
+tls_add_app_q_evt (application_t * app, stream_session_t * app_session)
+{
+  session_fifo_event_t evt;
+  svm_queue_t *q;
+
+  if (PREDICT_FALSE (app_session->session_state == SESSION_STATE_CLOSED))
+    {
+      /* Session is closed so app will never clean up. Flush rx fifo */
+      u32 to_dequeue = svm_fifo_max_dequeue (app_session->server_rx_fifo);
+      if (to_dequeue)
+	svm_fifo_dequeue_drop (app_session->server_rx_fifo, to_dequeue);
+      return 0;
+    }
+
+  if (app->cb_fns.builtin_app_rx_callback)
+    return app->cb_fns.builtin_app_rx_callback (app_session);
+
+  if (svm_fifo_set_event (app_session->server_rx_fifo))
+    {
+      evt.fifo = app_session->server_rx_fifo;
+      evt.event_type = FIFO_EVENT_APP_RX;
+      q = app->event_queue;
+
+      if (PREDICT_TRUE (q->cursize < q->maxsize))
+	{
+	  svm_queue_add (q, (u8 *) & evt, 0 /* do wait for mutex */ );
+	}
+      else
+	{
+	  clib_warning ("app evt q full");
+	  return -1;
+	}
+    }
+  return 0;
+}
+
+u32
+tls_listener_ctx_alloc (void)
+{
+  tls_main_t *tm = &tls_main;
+  tls_ctx_t *ctx;
+
+  pool_get (tm->listener_ctx_pool, ctx);
+  memset (ctx, 0, sizeof (*ctx));
+  return ctx - tm->listener_ctx_pool;
+}
+
+void
+tls_listener_ctx_free (tls_ctx_t * ctx)
+{
+  pool_put (tls_main.listener_ctx_pool, ctx);
+}
+
+tls_ctx_t *
+tls_listener_ctx_get (u32 ctx_index)
+{
+  return pool_elt_at_index (tls_main.listener_ctx_pool, ctx_index);
+}
+
+u32
+tls_listener_ctx_index (tls_ctx_t * ctx)
+{
+  return (ctx - tls_main.listener_ctx_pool);
+}
+
+u32
+tls_ctx_half_open_alloc (void)
+{
+  tls_main_t *tm = &tls_main;
+  u8 will_expand = 0;
+  tls_ctx_t *ctx;
+  u32 ctx_index;
+
+  pool_get_aligned_will_expand (tm->half_open_ctx_pool, will_expand, 0);
+  if (PREDICT_FALSE (will_expand && vlib_num_workers ()))
+    {
+      clib_rwlock_writer_lock (&tm->half_open_rwlock);
+      pool_get (tm->half_open_ctx_pool, ctx);
+      memset (ctx, 0, sizeof (*ctx));
+      ctx_index = ctx - tm->half_open_ctx_pool;
+      clib_rwlock_writer_unlock (&tm->half_open_rwlock);
+    }
+  else
+    {
+      pool_get (tm->half_open_ctx_pool, ctx);
+      memset (ctx, 0, sizeof (*ctx));
+      ctx_index = ctx - tm->half_open_ctx_pool;
+    }
+  return ctx_index;
+}
+
+void
+tls_ctx_half_open_free (u32 ho_index)
+{
+  tls_main_t *tm = &tls_main;
+  clib_rwlock_writer_lock (&tm->half_open_rwlock);
+  pool_put_index (tls_main.half_open_ctx_pool, ho_index);
+  clib_rwlock_writer_unlock (&tm->half_open_rwlock);
+}
+
+tls_ctx_t *
+tls_ctx_half_open_get (u32 ctx_index)
+{
+  tls_main_t *tm = &tls_main;
+  clib_rwlock_reader_lock (&tm->half_open_rwlock);
+  return pool_elt_at_index (tm->half_open_ctx_pool, ctx_index);
+}
+
+void
+tls_ctx_half_open_reader_unlock ()
+{
+  clib_rwlock_reader_unlock (&tls_main.half_open_rwlock);
+}
+
+u32
+tls_ctx_half_open_index (tls_ctx_t * ctx)
+{
+  return (ctx - tls_main.half_open_ctx_pool);
+}
+
+static int
+tls_notify_app_accept (tls_ctx_t * ctx)
+{
+  stream_session_t *app_listener, *app_session;
+  segment_manager_t *sm;
+  application_t *app;
+  tls_ctx_t *lctx;
+  int rv;
+
+  app = application_get (ctx->parent_app_index);
+  lctx = tls_listener_ctx_get (ctx->listener_ctx_index);
+  app_listener = listen_session_get_from_handle (lctx->app_session_handle);
+  sm = application_get_listen_segment_manager (app, app_listener);
+
+  app_session = session_alloc (vlib_get_thread_index ());
+  app_session->app_index = ctx->parent_app_index;
+  app_session->connection_index = ctx->tls_ctx_idx;
+  app_session->session_type = app_listener->session_type;
+  app_session->listener_index = app_listener->session_index;
+  if ((rv = session_alloc_fifos (sm, app_session)))
+    {
+      TLS_DBG (1, "failed to allocate fifos");
+      return rv;
+    }
+  ctx->c_s_index = app_session->session_index;
+  ctx->app_session_handle = session_handle (app_session);
+  return app->cb_fns.session_accept_callback (app_session);
+}
+
+static int
+tls_notify_app_connected (tls_ctx_t * ctx, u8 is_failed)
+{
+  int (*cb_fn) (u32, u32, stream_session_t *, u8);
+  stream_session_t *app_session;
+  segment_manager_t *sm;
+  application_t *app;
+
+  app = application_get (ctx->parent_app_index);
+  cb_fn = app->cb_fns.session_connected_callback;
+
+  if (is_failed)
+    goto failed;
+
+  sm = application_get_connect_segment_manager (app);
+  app_session = session_alloc (vlib_get_thread_index ());
+  app_session->app_index = ctx->parent_app_index;
+  app_session->connection_index = ctx->tls_ctx_idx;
+  app_session->session_type =
+    session_type_from_proto_and_ip (TRANSPORT_PROTO_TLS, ctx->tcp_is_ip4);
+  if (session_alloc_fifos (sm, app_session))
+    goto failed;
+
+  ctx->app_session_handle = session_handle (app_session);
+  ctx->c_s_index = app_session->session_index;
+  app_session->session_state = SESSION_STATE_READY;
+  if (cb_fn (ctx->parent_app_index, ctx->parent_app_api_context,
+	     app_session, 0 /* not failed */ ))
+    {
+      TLS_DBG (1, "failed to notify app");
+      tls_disconnect (ctx->tls_ctx_idx, vlib_get_thread_index ());
+    }
+
+  return 0;
+
+failed:
+  return cb_fn (ctx->parent_app_index, ctx->parent_app_api_context, 0,
+		1 /* failed */ );
+}
+
+static inline u32
+tls_ctx_alloc (void)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_alloc ();
+}
+
+static inline void
+tls_ctx_free (tls_ctx_t * ctx)
+{
+  vec_free (ctx->srv_hostname);
+  tls_vfts[DEFAULT_ENGINE].ctx_free (ctx);
+}
+
+static inline tls_ctx_t *
+tls_ctx_get (u32 ctx_index)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_get (ctx_index);
+}
+
+static inline tls_ctx_t *
+tls_ctx_get_w_thread (u32 ctx_index, u8 thread_index)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_get_w_thread (ctx_index, thread_index);
+}
+
+static inline int
+tls_ctx_init_server (tls_ctx_t * ctx)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_init_server (ctx);
+}
+
+static inline int
+tls_ctx_init_client (tls_ctx_t * ctx)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_init_client (ctx);
+}
+
+static inline int
+tls_ctx_write (tls_ctx_t * ctx, u8 * buf, u32 len)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_write (ctx, buf, len);
+}
+
+static inline int
+tls_ctx_read (tls_ctx_t * ctx, u8 * buf, u32 len)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_read (ctx, buf, len);
+}
+
+static inline u8
+tls_ctx_handshake_is_over (tls_ctx_t * ctx)
+{
+  return tls_vfts[DEFAULT_ENGINE].ctx_handshake_is_over (ctx);
+}
+
+static inline int
+tls_handshake_rx (tls_ctx_t * ctx)
+{
+  int rv;
+  rv = tls_vfts[DEFAULT_ENGINE].ctx_handshake_rx (ctx);
+
+  switch (rv)
+    {
+    case CLIENT_HANDSHAKE_OK:
+      tls_notify_app_connected (ctx, /* is failed */ 0);
+      break;
+    case CLIENT_HANDSHAKE_FAIL:
+      tls_disconnect (ctx->tls_ctx_idx, vlib_get_thread_index ());
+      tls_notify_app_connected (ctx, /* is failed */ 1);
+      break;
+    case SERVER_HANDSHAKE_OK:
+      tls_notify_app_accept (ctx);
+      break;
+    default:
+      return 0;
+    }
+  return 0;
+}
+
+void
+tls_session_reset_callback (stream_session_t * s)
+{
+  clib_warning ("called...");
+}
+
+int
+tls_add_segment_callback (u32 client_index, const ssvm_private_t * fs)
+{
+  /* No-op for builtin */
+  return 0;
+}
+
+int
+tls_del_segment_callback (u32 client_index, const ssvm_private_t * fs)
+{
+  return 0;
+}
+
+void
+tls_session_disconnect_callback (stream_session_t * tls_session)
+{
+  stream_session_t *app_session;
+  tls_ctx_t *ctx;
+  application_t *app;
+
+  ctx = tls_ctx_get (tls_session->opaque);
+  if (!tls_ctx_handshake_is_over (ctx))
+    {
+      stream_session_disconnect (tls_session);
+      return;
+    }
+  ctx->is_passive_close = 1;
+  app = application_get (ctx->parent_app_index);
+  app_session = session_get_from_handle (ctx->app_session_handle);
+  app->cb_fns.session_disconnect_callback (app_session);
+}
+
+int
+tls_session_accept_callback (stream_session_t * tls_session)
+{
+  stream_session_t *tls_listener;
+  tls_ctx_t *lctx, *ctx;
+  u32 ctx_index;
+
+  tls_listener = listen_session_get (tls_session->session_type,
+				     tls_session->listener_index);
+  lctx = tls_listener_ctx_get (tls_listener->opaque);
+  ctx_index = tls_ctx_alloc ();
+  ctx = tls_ctx_get (ctx_index);
+  memcpy (ctx, lctx, sizeof (*lctx));
+  ctx->c_thread_index = vlib_get_thread_index ();
+  ctx->tls_ctx_idx = ctx_index;
+  tls_session->session_state = SESSION_STATE_READY;
+  tls_session->opaque = ctx_index;
+  ctx->tls_session_handle = session_handle (tls_session);
+  ctx->listener_ctx_index = tls_listener->opaque;
+
+  TLS_DBG (1, "Accept on listener %u new connection [%u]%u",
+	   tls_listener->opaque, vlib_get_thread_index (), ctx_index);
+
+  return tls_ctx_init_server (ctx);
+}
+
+int
+tls_app_tx_callback (stream_session_t * app_session)
+{
+  stream_session_t *tls_session;
+  tls_ctx_t *ctx;
+  static u8 *tmp_buf;
+  u32 enq_max, deq_max, deq_now;
+  int wrote;
+
+  ctx = tls_ctx_get (app_session->connection_index);
+  if (!tls_ctx_handshake_is_over (ctx))
+    tls_add_vpp_q_evt (app_session->server_tx_fifo, FIFO_EVENT_APP_TX);
+
+  deq_max = svm_fifo_max_dequeue (app_session->server_tx_fifo);
+  if (!deq_max)
+    return 0;
+
+  tls_session = session_get_from_handle (ctx->tls_session_handle);
+  enq_max = svm_fifo_max_enqueue (tls_session->server_tx_fifo);
+  deq_now = clib_min (deq_max, TLS_CHUNK_SIZE);
+
+  if (PREDICT_FALSE (enq_max == 0))
+    {
+      tls_add_vpp_q_evt (app_session->server_tx_fifo, FIFO_EVENT_APP_TX);
+      return 0;
+    }
+
+  vec_validate (tmp_buf, deq_now);
+  svm_fifo_peek (app_session->server_tx_fifo, 0, deq_now, tmp_buf);
+  wrote = tls_ctx_write (ctx, tmp_buf, deq_now);
+  if (wrote <= 0)
+    {
+      tls_add_vpp_q_evt (app_session->server_tx_fifo, FIFO_EVENT_APP_TX);
+      return 0;
+    }
+
+  svm_fifo_dequeue_drop (app_session->server_tx_fifo, wrote);
+  vec_reset_length (tmp_buf);
+
+  tls_add_vpp_q_evt (tls_session->server_tx_fifo, FIFO_EVENT_APP_TX);
+
+  if (deq_now < deq_max)
+    tls_add_vpp_q_evt (app_session->server_tx_fifo, FIFO_EVENT_APP_TX);
+
+  return 0;
+}
+
+int
+tls_app_rx_callback (stream_session_t * tls_session)
+{
+  stream_session_t *app_session;
+  u32 deq_max, enq_max, enq_now;
+  application_t *app;
+  static u8 *tmp_buf;
+  tls_ctx_t *ctx;
+  int read, enq;
+
+  ctx = tls_ctx_get (tls_session->opaque);
+  if (!tls_ctx_handshake_is_over (ctx))
+    return tls_handshake_rx (ctx);
+
+  deq_max = svm_fifo_max_dequeue (tls_session->server_rx_fifo);
+  if (!deq_max)
+    return 0;
+
+  app_session = session_get_from_handle (ctx->app_session_handle);
+  enq_max = svm_fifo_max_enqueue (app_session->server_rx_fifo);
+  enq_now = clib_min (enq_max, TLS_CHUNK_SIZE);
+
+  if (PREDICT_FALSE (enq_now == 0))
+    {
+      tls_add_vpp_q_evt (tls_session->server_rx_fifo, FIFO_EVENT_BUILTIN_RX);
+      return 0;
+    }
+
+  vec_validate (tmp_buf, enq_now);
+  read = tls_ctx_read (ctx, tmp_buf, enq_now);
+  if (read <= 0)
+    {
+      tls_add_vpp_q_evt (tls_session->server_rx_fifo, FIFO_EVENT_BUILTIN_RX);
+      return 0;
+    }
+
+  enq = svm_fifo_enqueue_nowait (app_session->server_rx_fifo, read, tmp_buf);
+  ASSERT (enq == read);
+  vec_reset_length (tmp_buf);
+
+  if (svm_fifo_max_dequeue (tls_session->server_rx_fifo))
+    tls_add_vpp_q_evt (tls_session->server_rx_fifo, FIFO_EVENT_BUILTIN_RX);
+
+  app = application_get_if_valid (app_session->app_index);
+  return tls_add_app_q_evt (app, app_session);
+}
+
+int
+tls_session_connected_callback (u32 tls_app_index, u32 ho_ctx_index,
+				stream_session_t * tls_session, u8 is_fail)
+{
+  int (*cb_fn) (u32, u32, stream_session_t *, u8);
+  application_t *app;
+  tls_ctx_t *ho_ctx, *ctx;
+  u32 ctx_index;
+
+  ho_ctx = tls_ctx_half_open_get (ho_ctx_index);
+  app = application_get (ho_ctx->parent_app_index);
+  cb_fn = app->cb_fns.session_connected_callback;
+
+  if (is_fail)
+    {
+      tls_ctx_half_open_reader_unlock ();
+      tls_ctx_half_open_free (ho_ctx_index);
+      return cb_fn (ho_ctx->parent_app_index, ho_ctx->c_s_index, 0,
+		    1 /* failed */ );
+    }
+
+  ctx_index = tls_ctx_alloc ();
+  ctx = tls_ctx_get (ctx_index);
+  clib_memcpy (ctx, ho_ctx, sizeof (*ctx));
+  tls_ctx_half_open_reader_unlock ();
+  tls_ctx_half_open_free (ho_ctx_index);
+
+  ctx->c_thread_index = vlib_get_thread_index ();
+  ctx->tls_ctx_idx = ctx_index;
+
+  TLS_DBG (1, "TCP connect for %u returned %u. New connection [%u]%u",
+	   ho_ctx_index, is_fail, vlib_get_thread_index (),
+	   (ctx) ? ctx_index : ~0);
+
+  ctx->tls_session_handle = session_handle (tls_session);
+  tls_session->opaque = ctx_index;
+  tls_session->session_state = SESSION_STATE_READY;
+
+  return tls_ctx_init_client (ctx);
+}
+
+/* *INDENT-OFF* */
+static session_cb_vft_t tls_app_cb_vft = {
+  .session_accept_callback = tls_session_accept_callback,
+  .session_disconnect_callback = tls_session_disconnect_callback,
+  .session_connected_callback = tls_session_connected_callback,
+  .session_reset_callback = tls_session_reset_callback,
+  .add_segment_callback = tls_add_segment_callback,
+  .del_segment_callback = tls_del_segment_callback,
+  .builtin_app_rx_callback = tls_app_rx_callback,
+  .builtin_app_tx_callback = tls_app_tx_callback,
+};
+/* *INDENT-ON* */
+
+int
+tls_connect (transport_endpoint_t * tep)
+{
+  session_endpoint_extended_t *sep;
+  session_endpoint_t tls_sep;
+  tls_main_t *tm = &tls_main;
+  application_t *app;
+  tls_ctx_t *ctx;
+  u32 ctx_index;
+  int rv;
+
+  sep = (session_endpoint_extended_t *) tep;
+
+  ctx_index = tls_ctx_half_open_alloc ();
+  ctx = tls_ctx_half_open_get (ctx_index);
+  ctx->parent_app_index = sep->app_index;
+  ctx->parent_app_api_context = sep->opaque;
+  ctx->tcp_is_ip4 = sep->is_ip4;
+  if (sep->hostname)
+    {
+      ctx->srv_hostname = format (0, "%v", sep->hostname);
+      vec_terminate_c_string (ctx->srv_hostname);
+    }
+  tls_ctx_half_open_reader_unlock ();
+
+  app = application_get (sep->app_index);
+  application_alloc_connects_segment_manager (app);
+
+  clib_memcpy (&tls_sep, sep, sizeof (tls_sep));
+  tls_sep.transport_proto = TRANSPORT_PROTO_TCP;
+  if ((rv = application_connect (tm->app_index, ctx_index, &tls_sep)))
+    return rv;
+
+  TLS_DBG (1, "New connect request %u", ctx_index);
+  return 0;
+}
+
+void
+tls_disconnect (u32 ctx_index, u32 thread_index)
+{
+  stream_session_t *tls_session, *app_session;
+  tls_ctx_t *ctx;
+
+  TLS_DBG (1, "Disconnecting %u", ctx_index);
+
+  ctx = tls_ctx_get (ctx_index);
+  tls_session = session_get_from_handle (ctx->tls_session_handle);
+  stream_session_disconnect (tls_session);
+
+  app_session = session_get_from_handle_if_valid (ctx->app_session_handle);
+  if (app_session)
+    {
+      segment_manager_dealloc_fifos (app_session->svm_segment_index,
+				     app_session->server_rx_fifo,
+				     app_session->server_tx_fifo);
+      session_free (app_session);
+    }
+  tls_ctx_free (ctx);
+}
+
+u32
+tls_start_listen (u32 app_listener_index, transport_endpoint_t * tep)
+{
+  tls_main_t *tm = &tls_main;
+  application_t *tls_app;
+  session_handle_t tls_handle;
+  session_endpoint_extended_t *sep;
+  stream_session_t *tls_listener;
+  tls_ctx_t *lctx;
+  u32 lctx_index;
+  session_type_t st;
+  stream_session_t *app_listener;
+
+  sep = (session_endpoint_extended_t *) tep;
+  lctx_index = tls_listener_ctx_alloc ();
+  lctx = tls_listener_ctx_get (lctx_index);
+  st = session_type_from_proto_and_ip (sep->transport_proto, sep->is_ip4);
+  app_listener = listen_session_get (st, app_listener_index);
+
+  tls_app = application_get (tm->app_index);
+  sep->transport_proto = TRANSPORT_PROTO_TCP;
+  if (application_start_listen (tls_app, (session_endpoint_t *) sep,
+				&tls_handle))
+    return ~0;
+
+  tls_listener = listen_session_get_from_handle (tls_handle);
+  tls_listener->opaque = lctx_index;
+  lctx->parent_app_index = sep->app_index;
+  lctx->tls_session_handle = tls_handle;
+  lctx->app_session_handle = listen_session_get_handle (app_listener);
+  lctx->tcp_is_ip4 = sep->is_ip4;
+  return lctx_index;
+}
+
+u32
+tls_stop_listen (u32 lctx_index)
+{
+  tls_main_t *tm = &tls_main;
+  application_t *tls_app;
+  tls_ctx_t *lctx;
+  lctx = tls_listener_ctx_get (lctx_index);
+  tls_app = application_get (tm->app_index);
+  application_stop_listen (tls_app, lctx->tls_session_handle);
+  tls_listener_ctx_free (lctx);
+  return 0;
+}
+
+transport_connection_t *
+tls_connection_get (u32 ctx_index, u32 thread_index)
+{
+  tls_ctx_t *ctx;
+  ctx = tls_ctx_get_w_thread (ctx_index, thread_index);
+  return &ctx->connection;
+}
+
+transport_connection_t *
+tls_listener_get (u32 listener_index)
+{
+  tls_ctx_t *ctx;
+  ctx = tls_listener_ctx_get (listener_index);
+  return &ctx->connection;
+}
+
+u8 *
+format_tls_ctx (u8 * s, va_list * args)
+{
+  tls_ctx_t *ctx = va_arg (*args, tls_ctx_t *);
+  u32 thread_index = va_arg (*args, u32);
+  u32 child_si, child_ti;
+
+  session_parse_handle (ctx->tls_session_handle, &child_si, &child_ti);
+  if (thread_index != child_ti)
+    clib_warning ("app and tls sessions are on different threads!");
+
+  s = format (s, "[#%d][TLS] app %u child %u", child_ti,
+	      ctx->parent_app_index, child_si);
+  return s;
+}
+
+u8 *
+format_tls_connection (u8 * s, va_list * args)
+{
+  u32 ctx_index = va_arg (*args, u32);
+  u32 thread_index = va_arg (*args, u32);
+  u32 verbose = va_arg (*args, u32);
+  tls_ctx_t *ctx;
+
+  ctx = tls_ctx_get_w_thread (ctx_index, thread_index);
+  if (!ctx)
+    return s;
+
+  s = format (s, "%-50U", format_tls_ctx, ctx, thread_index);
+  if (verbose)
+    {
+      s = format (s, "%-15s", "state");
+      if (verbose > 1)
+	s = format (s, "\n");
+    }
+  return s;
+}
+
+u8 *
+format_tls_listener (u8 * s, va_list * args)
+{
+  u32 tc_index = va_arg (*args, u32);
+  tls_ctx_t *ctx = tls_listener_ctx_get (tc_index);
+  u32 listener_index, type;
+
+  listen_session_parse_handle (ctx->tls_session_handle, &type,
+			       &listener_index);
+  return format (s, "[TLS] listener app %u child %u", ctx->parent_app_index,
+		 listener_index);
+}
+
+u8 *
+format_tls_half_open (u8 * s, va_list * args)
+{
+  u32 tc_index = va_arg (*args, u32);
+  tls_ctx_t *ctx = tls_ctx_half_open_get (tc_index);
+  s = format (s, "[TLS] half-open app %u", ctx->parent_app_index);
+  tls_ctx_half_open_reader_unlock ();
+  return s;
+}
+
+/* *INDENT-OFF* */
+const static transport_proto_vft_t tls_proto = {
+  .open = tls_connect,
+  .close = tls_disconnect,
+  .bind = tls_start_listen,
+  .get_connection = tls_connection_get,
+  .get_listener = tls_listener_get,
+  .unbind = tls_stop_listen,
+  .tx_type = TRANSPORT_TX_INTERNAL,
+  .service_type = TRANSPORT_SERVICE_APP,
+  .format_connection = format_tls_connection,
+  .format_half_open = format_tls_half_open,
+  .format_listener = format_tls_listener,
+};
+/* *INDENT-ON* */
+
+void
+tls_register_engine (const tls_engine_vft_t * vft, tls_engine_type_t type)
+{
+  vec_validate (tls_vfts, type);
+  tls_vfts[type] = *vft;
+}
+
+clib_error_t *
+tls_init (vlib_main_t * vm)
+{
+  vnet_app_attach_args_t _a, *a = &_a;
+  u64 options[APP_OPTIONS_N_OPTIONS];
+  u32 segment_size = 512 << 20;
+  tls_main_t *tm = &tls_main;
+  u32 fifo_size = 64 << 10;
+
+  memset (a, 0, sizeof (*a));
+  memset (options, 0, sizeof (options));
+
+  a->session_cb_vft = &tls_app_cb_vft;
+  a->api_client_index = (1 << 24) + 1;
+  a->options = options;
+  a->options[APP_OPTIONS_SEGMENT_SIZE] = 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;
+
+  if (vnet_application_attach (a))
+    {
+      clib_warning ("failed to attach tls app");
+      return clib_error_return (0, "failed to attach tls app");
+    }
+
+  if (!tm->ca_cert_path)
+    tm->ca_cert_path = TLS_CA_CERT_PATH;
+
+  tm->app_index = a->app_index;
+  clib_rwlock_init (&tm->half_open_rwlock);
+
+  transport_register_protocol (TRANSPORT_PROTO_TLS, &tls_proto,
+			       FIB_PROTOCOL_IP4, ~0);
+  transport_register_protocol (TRANSPORT_PROTO_TLS, &tls_proto,
+			       FIB_PROTOCOL_IP6, ~0);
+
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (tls_init);
+
+static clib_error_t *
+tls_config_fn (vlib_main_t * vm, unformat_input_t * input)
+{
+  tls_main_t *tm = &tls_main;
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "use-test-cert-in-ca"))
+	tm->use_test_cert_in_ca = 1;
+      else if (unformat (input, "ca-cert-path %s", &tm->ca_cert_path))
+	;
+      else
+	return clib_error_return (0, "unknown input `%U'",
+				  format_unformat_error, input);
+    }
+  return 0;
+}
+
+VLIB_EARLY_CONFIG_FUNCTION (tls_config_fn, "tls");
+
+tls_main_t *
+vnet_tls_get_main (void)
+{
+  return &tls_main;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/tls/tls.h b/src/vnet/tls/tls.h
new file mode 100644
index 00000000000..0dfc48bd336
--- /dev/null
+++ b/src/vnet/tls/tls.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2018 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 <vnet/session/application_interface.h>
+#include <vppinfra/lock.h>
+
+#ifndef SRC_VNET_TLS_TLS_H_
+#define SRC_VNET_TLS_TLS_H_
+
+#define TLS_DEBUG 		0
+#define TLS_DEBUG_LEVEL_CLIENT 	0
+#define TLS_DEBUG_LEVEL_SERVER 	0
+
+#define TLS_CHUNK_SIZE 		(1 << 14)
+#define TLS_CA_CERT_PATH	"/etc/ssl/certs/ca-certificates.crt"
+
+#if TLS_DEBUG
+#define TLS_DBG(_lvl, _fmt, _args...) 			\
+  if (_lvl <= TLS_DEBUG) 				\
+    clib_warning (_fmt, ##_args)
+#else
+#define TLS_DBG(_fmt, _args...)
+#endif
+
+/* *INDENT-OFF* */
+typedef CLIB_PACKED (struct tls_cxt_id_
+{
+  u32 parent_app_index;
+  session_handle_t app_session_handle;
+  session_handle_t tls_session_handle;
+  u32 listener_ctx_index;
+  u8 tcp_is_ip4;
+}) tls_ctx_id_t;
+/* *INDENT-ON* */
+
+STATIC_ASSERT (sizeof (tls_ctx_id_t) <= 42, "ctx id must be less than 42");
+
+typedef struct tls_ctx_
+{
+  union
+  {
+    transport_connection_t connection;
+    tls_ctx_id_t c_tls_ctx_id;
+  };
+#define parent_app_index c_tls_ctx_id.parent_app_index
+#define app_session_handle c_tls_ctx_id.app_session_handle
+#define tls_session_handle c_tls_ctx_id.tls_session_handle
+#define listener_ctx_index c_tls_ctx_id.listener_ctx_index
+#define tcp_is_ip4 c_tls_ctx_id.tcp_is_ip4
+#define tls_ctx_idx c_c_index
+  /* Temporary storage for session open opaque. Overwritten once
+   * underlying tcp connection is established */
+#define parent_app_api_context c_s_index
+
+  u8 is_passive_close;
+  u8 *srv_hostname;
+} tls_ctx_t;
+
+typedef struct tls_main_
+{
+  u32 app_index;
+  tls_ctx_t *listener_ctx_pool;
+  tls_ctx_t *half_open_ctx_pool;
+  clib_rwlock_t half_open_rwlock;
+
+  /*
+   * Config
+   */
+  u8 use_test_cert_in_ca;
+  char *ca_cert_path;
+} tls_main_t;
+
+typedef struct tls_engine_vft_
+{
+  u32 (*ctx_alloc) (void);
+  void (*ctx_free) (tls_ctx_t * ctx);
+  tls_ctx_t *(*ctx_get) (u32 ctx_index);
+  tls_ctx_t *(*ctx_get_w_thread) (u32 ctx_index, u8 thread_index);
+  int (*ctx_init_client) (tls_ctx_t * ctx);
+  int (*ctx_init_server) (tls_ctx_t * ctx);
+  int (*ctx_read) (tls_ctx_t * ctx, u8 * buf, u32 len);
+  int (*ctx_write) (tls_ctx_t * ctx, u8 * buf, u32 len);
+  int (*ctx_handshake_rx) (tls_ctx_t * ctx);
+    u8 (*ctx_handshake_is_over) (tls_ctx_t * ctx);
+} tls_engine_vft_t;
+
+enum tls_handshake_results_
+{
+  HANDSHAKE_NOT_OVER,
+  CLIENT_HANDSHAKE_OK,
+  CLIENT_HANDSHAKE_FAIL,
+  SERVER_HANDSHAKE_OK
+};
+
+typedef enum tls_engine_type_
+{
+  TLS_ENGINE_MBEDTLS,
+  TLS_ENGINE_OPENSSL,
+  TLS_N_ENGINES
+} tls_engine_type_t;
+
+tls_main_t *vnet_tls_get_main (void);
+void tls_register_engine (const tls_engine_vft_t * vft,
+			  tls_engine_type_t type);
+int tls_add_vpp_q_evt (svm_fifo_t * f, u8 evt_type);
+
+#endif /* SRC_VNET_TLS_TLS_H_ */
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */