VPP-598: tcp stack initial commit

Change-Id: I49e5ce0aae6e4ff634024387ceaf7dbc432a0351
Signed-off-by: Dave Barach <dave@barachs.net>
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 954 insertions, 0 deletions

diff --git a/src/uri/uri_udp_test2.c b/src/uri/uri_udp_test2.c
new file mode 100644
index 00000000..ddfffaa6
--- /dev/null
+++ b/src/uri/uri_udp_test2.c
@@ -0,0 +1,954 @@
+/*
+ * Copyright (c) 2016 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 <stdio.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <vppinfra/clib.h>
+#include <vppinfra/format.h>
+#include <vppinfra/error.h>
+#include <vppinfra/time.h>
+#include <vppinfra/macros.h>
+#include <vnet/vnet.h>
+#include <vlib/vlib.h>
+#include <vlib/unix/unix.h>
+#include <vlibapi/api.h>
+#include <vlibmemory/api.h>
+#include <vpp/api/vpe_msg_enum.h>
+#include <svm/svm_fifo_segment.h>
+#include <pthread.h>
+
+#include "../vnet/session/application_interface.h"
+
+#define vl_typedefs		/* define message structures */
+#include <vpp/api/vpe_all_api_h.h>
+#undef vl_typedefs
+
+/* declare message handlers for each api */
+
+#define vl_endianfun		/* define message structures */
+#include <vpp/api/vpe_all_api_h.h>
+#undef vl_endianfun
+
+/* instantiate all the print functions we know about */
+#define vl_print(handle, ...)
+#define vl_printfun
+#include <vpp/api/vpe_all_api_h.h>
+#undef vl_printfun
+
+/* Satisfy external references when not linking with -lvlib */
+vlib_main_t vlib_global_main;
+vlib_main_t **vlib_mains;
+
+typedef enum
+{
+  STATE_START,
+  STATE_READY,
+  STATE_DISCONNECTING,
+} connection_state_t;
+
+typedef struct
+{
+  svm_fifo_t *server_rx_fifo;
+  svm_fifo_t *server_tx_fifo;
+} session_t;
+
+typedef struct
+{
+  /* vpe input queue */
+  unix_shared_memory_queue_t *vl_input_queue;
+
+  /* API client handle */
+  u32 my_client_index;
+
+  /* The URI we're playing with */
+  u8 *uri;
+
+  /* Session pool */
+  session_t *sessions;
+
+  /* Hash table for disconnect processing */
+  uword *session_index_by_vpp_handles;
+
+  /* fifo segment */
+  svm_fifo_segment_private_t *seg;
+
+  /* intermediate rx buffer */
+  u8 *rx_buf;
+
+  /* URI for connect */
+  u8 *connect_uri;
+
+  int i_am_master;
+
+  /* Our event queue */
+  unix_shared_memory_queue_t *our_event_queue;
+
+  /* $$$ single thread only for the moment */
+  unix_shared_memory_queue_t *vpp_event_queue;
+
+  /* $$$$ hack: cut-through session index */
+  volatile u32 cut_through_session_index;
+
+  /* unique segment name counter */
+  u32 unique_segment_index;
+
+  pid_t my_pid;
+
+  /* pthread handle */
+  pthread_t cut_through_thread_handle;
+
+  /* For deadman timers */
+  clib_time_t clib_time;
+
+  /* State of the connection, shared between msg RX thread and main thread */
+  volatile connection_state_t state;
+
+  volatile int time_to_stop;
+  volatile int time_to_print_stats;
+
+  u32 configured_segment_size;
+
+  /* VNET_API_ERROR_FOO -> "Foo" hash table */
+  uword *error_string_by_error_number;
+
+  /* convenience */
+  svm_fifo_segment_main_t *segment_main;
+
+} uri_udp_test_main_t;
+
+#if CLIB_DEBUG > 0
+#define NITER 10000
+#else
+#define NITER 4000000
+#endif
+
+uri_udp_test_main_t uri_udp_test_main;
+
+static void
+stop_signal (int signum)
+{
+  uri_udp_test_main_t *um = &uri_udp_test_main;
+
+  um->time_to_stop = 1;
+}
+
+static void
+stats_signal (int signum)
+{
+  uri_udp_test_main_t *um = &uri_udp_test_main;
+
+  um->time_to_print_stats = 1;
+}
+
+static clib_error_t *
+setup_signal_handlers (void)
+{
+  signal (SIGINT, stats_signal);
+  signal (SIGQUIT, stop_signal);
+  signal (SIGTERM, stop_signal);
+
+  return 0;
+}
+
+u8 *
+format_api_error (u8 * s, va_list * args)
+{
+  uri_udp_test_main_t *utm = va_arg (*args, uri_udp_test_main_t *);
+  i32 error = va_arg (*args, u32);
+  uword *p;
+
+  p = hash_get (utm->error_string_by_error_number, -error);
+
+  if (p)
+    s = format (s, "%s", p[0]);
+  else
+    s = format (s, "%d", error);
+  return s;
+}
+
+int
+wait_for_state_change (uri_udp_test_main_t * utm, connection_state_t state)
+{
+#if CLIB_DEBUG > 0
+#define TIMEOUT 600.0
+#else
+#define TIMEOUT 600.0
+#endif
+
+  f64 timeout = clib_time_now (&utm->clib_time) + TIMEOUT;
+
+  while (clib_time_now (&utm->clib_time) < timeout)
+    {
+      if (utm->state == state)
+	return 0;
+    }
+  return -1;
+}
+
+u64 server_bytes_received, server_bytes_sent;
+
+static void *
+cut_through_thread_fn (void *arg)
+{
+  session_t *s;
+  svm_fifo_t *rx_fifo;
+  svm_fifo_t *tx_fifo;
+  u8 *my_copy_buffer = 0;
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  i32 actual_transfer;
+  int rv;
+  u32 buffer_offset;
+
+  while (utm->cut_through_session_index == ~0)
+    ;
+
+  s = pool_elt_at_index (utm->sessions, utm->cut_through_session_index);
+
+  rx_fifo = s->server_rx_fifo;
+  tx_fifo = s->server_tx_fifo;
+
+  vec_validate (my_copy_buffer, 64 * 1024 - 1);
+
+  while (true)
+    {
+      /* We read from the tx fifo and write to the rx fifo */
+      do
+	{
+	  actual_transfer = svm_fifo_dequeue_nowait (tx_fifo, 0,
+						     vec_len (my_copy_buffer),
+						     my_copy_buffer);
+	}
+      while (actual_transfer <= 0);
+
+      server_bytes_received += actual_transfer;
+
+      buffer_offset = 0;
+      while (actual_transfer > 0)
+	{
+	  rv = svm_fifo_enqueue_nowait (rx_fifo, 0, actual_transfer,
+					my_copy_buffer + buffer_offset);
+	  if (rv > 0)
+	    {
+	      actual_transfer -= rv;
+	      buffer_offset += rv;
+	      server_bytes_sent += rv;
+	    }
+
+	}
+      if (PREDICT_FALSE (utm->time_to_stop))
+	break;
+    }
+
+  pthread_exit (0);
+}
+
+static void
+uri_udp_slave_test (uri_udp_test_main_t * utm)
+{
+  vl_api_connect_uri_t *cmp;
+  int i;
+  u8 *test_data = 0;
+  u64 bytes_received = 0, bytes_sent = 0;
+  i32 bytes_to_read;
+  int rv;
+  int mypid = getpid ();
+  f64 before, after, delta, bytes_per_second;
+  session_t *session;
+  svm_fifo_t *rx_fifo, *tx_fifo;
+  int buffer_offset, bytes_to_send = 0;
+
+  vec_validate (test_data, 64 * 1024 - 1);
+  for (i = 0; i < vec_len (test_data); i++)
+    test_data[i] = i & 0xff;
+
+  cmp = vl_msg_api_alloc (sizeof (*cmp));
+  memset (cmp, 0, sizeof (*cmp));
+
+  cmp->_vl_msg_id = ntohs (VL_API_CONNECT_URI);
+  cmp->client_index = utm->my_client_index;
+  cmp->context = ntohl (0xfeedface);
+  memcpy (cmp->uri, utm->connect_uri, vec_len (utm->connect_uri));
+  vl_msg_api_send_shmem (utm->vl_input_queue, (u8 *) & cmp);
+
+  if (wait_for_state_change (utm, STATE_READY))
+    {
+      clib_warning ("timeout waiting for STATE_READY");
+      return;
+    }
+
+  session = pool_elt_at_index (utm->sessions, utm->cut_through_session_index);
+  rx_fifo = session->server_rx_fifo;
+  tx_fifo = session->server_tx_fifo;
+
+  before = clib_time_now (&utm->clib_time);
+
+  vec_validate (utm->rx_buf, vec_len (test_data) - 1);
+
+  for (i = 0; i < NITER; i++)
+    {
+      bytes_to_send = vec_len (test_data);
+      buffer_offset = 0;
+      while (bytes_to_send > 0)
+	{
+	  rv = svm_fifo_enqueue_nowait (tx_fifo, mypid,
+					bytes_to_send,
+					test_data + buffer_offset);
+
+	  if (rv > 0)
+	    {
+	      bytes_to_send -= rv;
+	      buffer_offset += rv;
+	      bytes_sent += rv;
+	    }
+	}
+
+      bytes_to_read = svm_fifo_max_dequeue (rx_fifo);
+
+      bytes_to_read = vec_len (utm->rx_buf) > bytes_to_read ?
+	bytes_to_read : vec_len (utm->rx_buf);
+
+      buffer_offset = 0;
+      while (bytes_to_read > 0)
+	{
+	  rv = svm_fifo_dequeue_nowait (rx_fifo, mypid,
+					bytes_to_read,
+					utm->rx_buf + buffer_offset);
+	  if (rv > 0)
+	    {
+	      bytes_to_read -= rv;
+	      buffer_offset += rv;
+	      bytes_received += rv;
+	    }
+	}
+    }
+  while (bytes_received < bytes_sent)
+    {
+      rv = svm_fifo_dequeue_nowait (rx_fifo, mypid,
+				    vec_len (utm->rx_buf), utm->rx_buf);
+      if (rv > 0)
+	{
+#if CLIB_DEBUG > 0
+	  int j;
+	  for (j = 0; j < rv; j++)
+	    {
+	      if (utm->rx_buf[j] != ((bytes_received + j) & 0xff))
+		{
+		  clib_warning ("error at byte %lld, 0x%x not 0x%x",
+				bytes_received + j,
+				utm->rx_buf[j],
+				((bytes_received + j) & 0xff));
+		}
+	    }
+#endif
+	  bytes_received += (u64) rv;
+	}
+    }
+
+  after = clib_time_now (&utm->clib_time);
+  delta = after - before;
+  bytes_per_second = 0.0;
+
+  if (delta > 0.0)
+    bytes_per_second = (f64) bytes_received / delta;
+
+  fformat (stdout,
+	   "Done: %lld recv bytes in %.2f seconds, %.2f bytes/sec...\n\n",
+	   bytes_received, delta, bytes_per_second);
+  fformat (stdout,
+	   "Done: %lld sent bytes in %.2f seconds, %.2f bytes/sec...\n\n",
+	   bytes_sent, delta, bytes_per_second);
+  fformat (stdout,
+	   "client -> server -> client round trip: %.2f Gbit/sec \n\n",
+	   (bytes_per_second * 8.0) / 1e9);
+}
+
+static void
+vl_api_bind_uri_reply_t_handler (vl_api_bind_uri_reply_t * mp)
+{
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  svm_fifo_segment_create_args_t _a, *a = &_a;
+  int rv;
+
+  if (mp->segment_name_length == 0)
+    {
+      clib_warning ("segment_name_length zero");
+      return;
+    }
+
+  a->segment_name = (char *) mp->segment_name;
+  a->segment_size = mp->segment_size;
+
+  ASSERT (mp->server_event_queue_address);
+
+  /* Attach to the segment vpp created */
+  rv = svm_fifo_segment_attach (a);
+  if (rv)
+    {
+      clib_warning ("svm_fifo_segment_attach ('%s') failed",
+		    mp->segment_name);
+      return;
+    }
+
+  utm->our_event_queue = (unix_shared_memory_queue_t *)
+    mp->server_event_queue_address;
+
+  utm->state = STATE_READY;
+}
+
+static void
+vl_api_map_another_segment_t_handler (vl_api_map_another_segment_t * mp)
+{
+  svm_fifo_segment_create_args_t _a, *a = &_a;
+  int rv;
+
+  a->segment_name = (char *) mp->segment_name;
+  a->segment_size = mp->segment_size;
+  /* Attach to the segment vpp created */
+  rv = svm_fifo_segment_attach (a);
+  if (rv)
+    {
+      clib_warning ("svm_fifo_segment_attach ('%s') failed",
+		    mp->segment_name);
+      return;
+    }
+  clib_warning ("Mapped new segment '%s' size %d", mp->segment_name,
+		mp->segment_size);
+}
+
+static void
+vl_api_connect_uri_t_handler (vl_api_connect_uri_t * mp)
+{
+  u32 segment_index;
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  svm_fifo_segment_main_t *sm = &svm_fifo_segment_main;
+  svm_fifo_segment_create_args_t _a, *a = &_a;
+  svm_fifo_segment_private_t *seg;
+  unix_shared_memory_queue_t *client_q;
+  vl_api_connect_uri_reply_t *rmp;
+  session_t *session;
+  int rv = 0;
+
+  /* Create the segment */
+  a->segment_name = (char *) format (0, "%d:segment%d%c", utm->my_pid,
+				     utm->unique_segment_index++, 0);
+  a->segment_size = utm->configured_segment_size;
+
+  rv = svm_fifo_segment_create (a);
+  if (rv)
+    {
+      clib_warning ("sm_fifo_segment_create ('%s') failed", a->segment_name);
+      rv = VNET_API_ERROR_URI_FIFO_CREATE_FAILED;
+      goto send_reply;
+    }
+
+  vec_add2 (utm->seg, seg, 1);
+
+  segment_index = vec_len (sm->segments) - 1;
+
+  memcpy (seg, sm->segments + segment_index, sizeof (utm->seg[0]));
+
+  pool_get (utm->sessions, session);
+
+  /*
+   * By construction the master's idea of the rx fifo ends up in
+   * fsh->fifos[0], and the master's idea of the tx fifo ends up in
+   * fsh->fifos[1].
+   */
+  session->server_rx_fifo = svm_fifo_segment_alloc_fifo (utm->seg,
+							 128 * 1024);
+  ASSERT (session->server_rx_fifo);
+
+  session->server_tx_fifo = svm_fifo_segment_alloc_fifo (utm->seg,
+							 128 * 1024);
+  ASSERT (session->server_tx_fifo);
+
+  session->server_rx_fifo->server_session_index = session - utm->sessions;
+  session->server_tx_fifo->server_session_index = session - utm->sessions;
+  utm->cut_through_session_index = session - utm->sessions;
+
+  rv = pthread_create (&utm->cut_through_thread_handle,
+		       NULL /*attr */ , cut_through_thread_fn, 0);
+  if (rv)
+    {
+      clib_warning ("pthread_create returned %d", rv);
+      rv = VNET_API_ERROR_SYSCALL_ERROR_1;
+    }
+
+send_reply:
+  rmp = vl_msg_api_alloc (sizeof (*rmp));
+  memset (rmp, 0, sizeof (*rmp));
+
+  rmp->_vl_msg_id = ntohs (VL_API_CONNECT_URI_REPLY);
+  rmp->context = mp->context;
+  rmp->retval = ntohl (rv);
+  rmp->segment_name_length = vec_len (a->segment_name);
+  memcpy (rmp->segment_name, a->segment_name, vec_len (a->segment_name));
+
+  vec_free (a->segment_name);
+
+  client_q = (unix_shared_memory_queue_t *) mp->client_queue_address;
+  vl_msg_api_send_shmem (client_q, (u8 *) & rmp);
+}
+
+static void
+vl_api_unbind_uri_reply_t_handler (vl_api_unbind_uri_reply_t * mp)
+{
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+
+  if (mp->retval != 0)
+    clib_warning ("returned %d", ntohl (mp->retval));
+
+  utm->state = STATE_START;
+}
+
+static void
+vl_api_accept_session_t_handler (vl_api_accept_session_t * mp)
+{
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  vl_api_accept_session_reply_t *rmp;
+  svm_fifo_t *rx_fifo, *tx_fifo;
+  session_t *session;
+  static f64 start_time;
+  u64 key;
+
+  if (start_time == 0.0)
+    start_time = clib_time_now (&utm->clib_time);
+
+  utm->vpp_event_queue = (unix_shared_memory_queue_t *)
+    mp->vpp_event_queue_address;
+
+  pool_get (utm->sessions, session);
+
+  rx_fifo = (svm_fifo_t *) mp->server_rx_fifo;
+  rx_fifo->client_session_index = session - utm->sessions;
+  tx_fifo = (svm_fifo_t *) mp->server_tx_fifo;
+  tx_fifo->client_session_index = session - utm->sessions;
+
+  session->server_rx_fifo = rx_fifo;
+  session->server_tx_fifo = tx_fifo;
+
+  key = (((u64) mp->session_thread_index) << 32) | (u64) mp->session_index;
+
+  hash_set (utm->session_index_by_vpp_handles, key, session - utm->sessions);
+
+  utm->state = STATE_READY;
+
+  if (pool_elts (utm->sessions) && (pool_elts (utm->sessions) % 20000) == 0)
+    {
+      f64 now = clib_time_now (&utm->clib_time);
+      fformat (stdout, "%d active sessions in %.2f seconds, %.2f/sec...\n",
+	       pool_elts (utm->sessions), now - start_time,
+	       (f64) pool_elts (utm->sessions) / (now - start_time));
+    }
+
+  rmp = vl_msg_api_alloc (sizeof (*rmp));
+  memset (rmp, 0, sizeof (*rmp));
+  rmp->_vl_msg_id = ntohs (VL_API_ACCEPT_SESSION_REPLY);
+  rmp->session_type = mp->session_type;
+  rmp->session_index = mp->session_index;
+  rmp->session_thread_index = mp->session_thread_index;
+  vl_msg_api_send_shmem (utm->vl_input_queue, (u8 *) & rmp);
+}
+
+static void
+vl_api_disconnect_session_t_handler (vl_api_disconnect_session_t * mp)
+{
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  session_t *session;
+  vl_api_disconnect_session_reply_t *rmp;
+  uword *p;
+  int rv = 0;
+  u64 key;
+
+  key = (((u64) mp->session_thread_index) << 32) | (u64) mp->session_index;
+
+  p = hash_get (utm->session_index_by_vpp_handles, key);
+
+  if (p)
+    {
+      session = pool_elt_at_index (utm->sessions, p[0]);
+      hash_unset (utm->session_index_by_vpp_handles, key);
+      pool_put (utm->sessions, session);
+    }
+  else
+    {
+      clib_warning ("couldn't find session key %llx", key);
+      rv = -11;
+    }
+
+  rmp = vl_msg_api_alloc (sizeof (*rmp));
+  memset (rmp, 0, sizeof (*rmp));
+  rmp->_vl_msg_id = ntohs (VL_API_DISCONNECT_SESSION_REPLY);
+  rmp->retval = rv;
+  rmp->session_index = mp->session_index;
+  rmp->session_thread_index = mp->session_thread_index;
+  vl_msg_api_send_shmem (utm->vl_input_queue, (u8 *) & rmp);
+}
+
+static void
+vl_api_connect_uri_reply_t_handler (vl_api_connect_uri_reply_t * mp)
+{
+  svm_fifo_segment_main_t *sm = &svm_fifo_segment_main;
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  svm_fifo_segment_create_args_t _a, *a = &_a;
+  ssvm_shared_header_t *sh;
+  svm_fifo_segment_private_t *seg;
+  svm_fifo_segment_header_t *fsh;
+  session_t *session;
+  u32 segment_index;
+  int rv;
+
+  ASSERT (utm->i_am_master == 0);
+
+  if (mp->segment_name_length == 0)
+    {
+      clib_warning ("segment_name_length zero");
+      return;
+    }
+
+  memset (a, 0, sizeof (*a));
+
+  a->segment_name = (char *) mp->segment_name;
+
+  sleep (1);
+
+  rv = svm_fifo_segment_attach (a);
+  if (rv)
+    {
+      clib_warning ("sm_fifo_segment_create ('%v') failed", mp->segment_name);
+      return;
+    }
+
+  segment_index = vec_len (sm->segments) - 1;
+
+  vec_add2 (utm->seg, seg, 1);
+
+  memcpy (seg, sm->segments + segment_index, sizeof (*seg));
+  sh = seg->ssvm.sh;
+  fsh = (svm_fifo_segment_header_t *) sh->opaque[0];
+
+  while (vec_len (fsh->fifos) < 2)
+    sleep (1);
+
+  pool_get (utm->sessions, session);
+  utm->cut_through_session_index = session - utm->sessions;
+
+  session->server_rx_fifo = (svm_fifo_t *) fsh->fifos[0];
+  ASSERT (session->server_rx_fifo);
+  session->server_tx_fifo = (svm_fifo_t *) fsh->fifos[1];
+  ASSERT (session->server_tx_fifo);
+
+  /* security: could unlink /dev/shm/<mp->segment_name> here, maybe */
+
+  utm->state = STATE_READY;
+}
+
+#define foreach_uri_msg                         \
+_(BIND_URI_REPLY, bind_uri_reply)               \
+_(CONNECT_URI, connect_uri)                     \
+_(CONNECT_URI_REPLY, connect_uri_reply)         \
+_(UNBIND_URI_REPLY, unbind_uri_reply)           \
+_(ACCEPT_SESSION, accept_session)		\
+_(DISCONNECT_SESSION, disconnect_session)	\
+_(MAP_ANOTHER_SEGMENT, map_another_segment)
+
+void
+uri_api_hookup (uri_udp_test_main_t * utm)
+{
+#define _(N,n)                                                  \
+    vl_msg_api_set_handlers(VL_API_##N, #n,                     \
+                           vl_api_##n##_t_handler,              \
+                           vl_noop_handler,                     \
+                           vl_api_##n##_t_endian,               \
+                           vl_api_##n##_t_print,                \
+                           sizeof(vl_api_##n##_t), 1);
+  foreach_uri_msg;
+#undef _
+
+}
+
+
+int
+connect_to_vpp (char *name)
+{
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  api_main_t *am = &api_main;
+
+  if (vl_client_connect_to_vlib ("/vpe-api", name, 32) < 0)
+    return -1;
+
+  utm->vl_input_queue = am->shmem_hdr->vl_input_queue;
+  utm->my_client_index = am->my_client_index;
+
+  return 0;
+}
+
+void
+vlib_cli_output (struct vlib_main_t *vm, char *fmt, ...)
+{
+  clib_warning ("BUG");
+}
+
+static void
+init_error_string_table (uri_udp_test_main_t * utm)
+{
+  utm->error_string_by_error_number = hash_create (0, sizeof (uword));
+
+#define _(n,v,s) hash_set (utm->error_string_by_error_number, -v, s);
+  foreach_vnet_api_error;
+#undef _
+
+  hash_set (utm->error_string_by_error_number, 99, "Misc");
+}
+
+void
+handle_fifo_event_server_rx (uri_udp_test_main_t * utm,
+			     session_fifo_event_t * e)
+{
+  svm_fifo_t *rx_fifo, *tx_fifo;
+  int nbytes;
+
+  session_fifo_event_t evt;
+  unix_shared_memory_queue_t *q;
+  int rv;
+
+  rx_fifo = e->fifo;
+  tx_fifo = utm->sessions[rx_fifo->client_session_index].server_tx_fifo;
+
+  do
+    {
+      nbytes = svm_fifo_dequeue_nowait (rx_fifo, 0,
+					vec_len (utm->rx_buf), utm->rx_buf);
+    }
+  while (nbytes <= 0);
+  do
+    {
+      rv = svm_fifo_enqueue_nowait (tx_fifo, 0, nbytes, utm->rx_buf);
+    }
+  while (rv == -2);
+
+  /* Fabricate TX event, send to vpp */
+  evt.fifo = tx_fifo;
+  evt.event_type = FIFO_EVENT_SERVER_TX;
+  /* $$$$ for event logging */
+  evt.enqueue_length = nbytes;
+  evt.event_id = e->event_id;
+  q = utm->vpp_event_queue;
+  unix_shared_memory_queue_add (q, (u8 *) & evt, 0 /* do wait for mutex */ );
+}
+
+void
+handle_event_queue (uri_udp_test_main_t * utm)
+{
+  session_fifo_event_t _e, *e = &_e;;
+
+  while (1)
+    {
+      unix_shared_memory_queue_sub (utm->our_event_queue, (u8 *) e,
+				    0 /* nowait */ );
+      switch (e->event_type)
+	{
+	case FIFO_EVENT_SERVER_RX:
+	  handle_fifo_event_server_rx (utm, e);
+	  break;
+
+	case FIFO_EVENT_SERVER_EXIT:
+	  return;
+
+	default:
+	  clib_warning ("unknown event type %d", e->event_type);
+	  break;
+	}
+      if (PREDICT_FALSE (utm->time_to_stop == 1))
+	break;
+      if (PREDICT_FALSE (utm->time_to_print_stats == 1))
+	{
+	  utm->time_to_print_stats = 0;
+	  fformat (stdout, "%d connections\n", pool_elts (utm->sessions));
+	}
+    }
+}
+
+void
+uri_udp_test (uri_udp_test_main_t * utm)
+{
+  vl_api_bind_uri_t *bmp;
+  vl_api_unbind_uri_t *ump;
+
+  bmp = vl_msg_api_alloc (sizeof (*bmp));
+  memset (bmp, 0, sizeof (*bmp));
+
+  bmp->_vl_msg_id = ntohs (VL_API_BIND_URI);
+  bmp->client_index = utm->my_client_index;
+  bmp->context = ntohl (0xfeedface);
+  bmp->initial_segment_size = 256 << 20;	/* size of initial segment */
+  bmp->options[SESSION_OPTIONS_FLAGS] =
+    SESSION_OPTIONS_FLAGS_USE_FIFO | SESSION_OPTIONS_FLAGS_ADD_SEGMENT;
+  bmp->options[SESSION_OPTIONS_RX_FIFO_SIZE] = 16 << 10;
+  bmp->options[SESSION_OPTIONS_TX_FIFO_SIZE] = 16 << 10;
+  bmp->options[SESSION_OPTIONS_ADD_SEGMENT_SIZE] = 128 << 20;
+  memcpy (bmp->uri, utm->uri, vec_len (utm->uri));
+  vl_msg_api_send_shmem (utm->vl_input_queue, (u8 *) & bmp);
+
+  if (wait_for_state_change (utm, STATE_READY))
+    {
+      clib_warning ("timeout waiting for STATE_READY");
+      return;
+    }
+
+  handle_event_queue (utm);
+
+  ump = vl_msg_api_alloc (sizeof (*ump));
+  memset (ump, 0, sizeof (*ump));
+
+  ump->_vl_msg_id = ntohs (VL_API_UNBIND_URI);
+  ump->client_index = utm->my_client_index;
+  memcpy (ump->uri, utm->uri, vec_len (utm->uri));
+  vl_msg_api_send_shmem (utm->vl_input_queue, (u8 *) & ump);
+
+  if (wait_for_state_change (utm, STATE_START))
+    {
+      clib_warning ("timeout waiting for STATE_START");
+      return;
+    }
+
+  fformat (stdout, "Test complete...\n");
+}
+
+int
+main (int argc, char **argv)
+{
+  uri_udp_test_main_t *utm = &uri_udp_test_main;
+  unformat_input_t _argv, *a = &_argv;
+  u8 *chroot_prefix;
+  u8 *heap;
+  u8 *bind_name = (u8 *) "udp://0.0.0.0/1234";
+  u32 tmp;
+  mheap_t *h;
+  session_t *session;
+  int i;
+  int i_am_master = 1;
+
+  clib_mem_init (0, 256 << 20);
+
+  heap = clib_mem_get_per_cpu_heap ();
+  h = mheap_header (heap);
+
+  /* make the main heap thread-safe */
+  h->flags |= MHEAP_FLAG_THREAD_SAFE;
+
+  vec_validate (utm->rx_buf, 8192);
+
+  utm->session_index_by_vpp_handles = hash_create (0, sizeof (uword));
+
+  utm->my_pid = getpid ();
+  utm->configured_segment_size = 1 << 20;
+
+  clib_time_init (&utm->clib_time);
+  init_error_string_table (utm);
+  svm_fifo_segment_init (0x200000000ULL, 20);
+  unformat_init_command_line (a, argv);
+
+  while (unformat_check_input (a) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (a, "chroot prefix %s", &chroot_prefix))
+	{
+	  vl_set_memory_root_path ((char *) chroot_prefix);
+	}
+      else if (unformat (a, "uri %s", &bind_name))
+	;
+      else if (unformat (a, "segment-size %dM", &tmp))
+	utm->configured_segment_size = tmp << 20;
+      else if (unformat (a, "segment-size %dG", &tmp))
+	utm->configured_segment_size = tmp << 30;
+      else if (unformat (a, "master"))
+	i_am_master = 1;
+      else if (unformat (a, "slave"))
+	i_am_master = 0;
+      else
+	{
+	  fformat (stderr, "%s: usage [master|slave]\n");
+	  exit (1);
+	}
+    }
+
+  utm->cut_through_session_index = ~0;
+  utm->uri = format (0, "%s%c", bind_name, 0);
+  utm->i_am_master = i_am_master;
+  utm->segment_main = &svm_fifo_segment_main;
+
+  utm->connect_uri = format (0, "udp://10.0.0.1/1234%c", 0);
+
+  setup_signal_handlers ();
+
+  uri_api_hookup (utm);
+
+  if (connect_to_vpp (i_am_master ? "uri_udp_master" : "uri_udp_slave") < 0)
+    {
+      svm_region_exit ();
+      fformat (stderr, "Couldn't connect to vpe, exiting...\n");
+      exit (1);
+    }
+
+  if (i_am_master == 0)
+    {
+      uri_udp_slave_test (utm);
+      exit (0);
+    }
+
+  /* $$$$ hack preallocation */
+  for (i = 0; i < 200000; i++)
+    {
+      pool_get (utm->sessions, session);
+      memset (session, 0, sizeof (*session));
+    }
+  for (i = 0; i < 200000; i++)
+    pool_put_index (utm->sessions, i);
+
+  uri_udp_test (utm);
+
+  vl_client_disconnect_from_vlib ();
+  exit (0);
+}
+
+#undef vl_api_version
+#define vl_api_version(n,v) static u32 vpe_api_version = v;
+#include <vpp/api/vpe.api.h>
+#undef vl_api_version
+
+void
+vl_client_add_api_signatures (vl_api_memclnt_create_t * mp)
+{
+  /*
+   * Send the main API signature in slot 0. This bit of code must
+   * match the checks in ../vpe/api/api.c: vl_msg_api_version_check().
+   */
+  mp->api_versions[0] = clib_host_to_net_u32 (vpe_api_version);
+}
+
+u32
+vl (void *p)
+{
+  return vec_len (p);
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */