Create a unit-test plugin

Move the tcp unit test to the plugin
Add a bihash unit test and a "make test" program to call it
Adjust framework.py to load the plugin, which is disabled by default

Change-Id: Ic229d386a56a9d28dbd54974f231149053ca8f93
Signed-off-by: Dave Barach <dave@barachs.net>

6 files changed, 2386 insertions, 0 deletions

diff --git a/src/plugins/Makefile.am b/src/plugins/Makefile.am
index 3220b098303..e1ead76f801 100644
--- a/src/plugins/Makefile.am
+++ b/src/plugins/Makefile.am
@@ -139,6 +139,10 @@ if ENABLE_TLSOPENSSL_PLUGIN
 include tlsopenssl.am
 endif
 
+if ENABLE_UNITTEST_PLUGIN
+include unittest.am
+endif
+
 include ../suffix-rules.mk
 
 # Remove *.la files
diff --git a/src/plugins/unittest.am b/src/plugins/unittest.am
new file mode 100644
index 00000000000..3fba00ff85b
--- /dev/null
+++ b/src/plugins/unittest.am
@@ -0,0 +1,22 @@
+
+# Copyright (c) <current-year> <your-organization>
+# 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.
+
+vppplugins_LTLIBRARIES += unittest_plugin.la
+
+unittest_plugin_la_SOURCES = \
+  unittest/unittest.c \
+  unittest/tcp_test.c \
+  unittest/bihash_test.c
+
+# vi:syntax=automake
diff --git a/src/plugins/unittest/bihash_test.c b/src/plugins/unittest/bihash_test.c
new file mode 100644
index 00000000000..7604f977554
--- /dev/null
+++ b/src/plugins/unittest/bihash_test.c
@@ -0,0 +1,490 @@
+/*
+ * Copyright (c) 2015 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 <vlib/vlib.h>
+#include <vppinfra/time.h>
+#include <vppinfra/cache.h>
+#include <vppinfra/error.h>
+#include <sys/resource.h>
+#include <stdio.h>
+#include <pthread.h>
+
+#include <vppinfra/bihash_8_8.h>
+#include <vppinfra/bihash_template.h>
+
+#include <vppinfra/bihash_template.c>
+
+typedef struct
+{
+  volatile u32 thread_barrier;
+  volatile u32 threads_running;
+  volatile u64 sequence_number;
+  u64 seed;
+  u32 nbuckets;
+  u32 nitems;
+  u32 ncycles;
+  u32 report_every_n;
+  u32 search_iter;
+  int careful_delete_tests;
+  int verbose;
+  int non_random_keys;
+  u32 nthreads;
+  uword *key_hash;
+  u64 *keys;
+  uword hash_memory_size;
+    BVT (clib_bihash) hash;
+  clib_time_t clib_time;
+  void *global_heap;
+
+  unformat_input_t *input;
+
+  /* convenience */
+  vlib_main_t *vlib_main;
+} bihash_test_main_t;
+
+static bihash_test_main_t bihash_test_main;
+
+static clib_error_t *
+test_bihash_vec64 (bihash_test_main_t * tm)
+{
+  u32 user_buckets = 1228800;
+  u32 user_memory_size = 209715200;
+  BVT (clib_bihash_kv) kv;
+  int i, j;
+  f64 before;
+  f64 *cum_times = 0;
+  BVT (clib_bihash) * h;
+
+  h = &tm->hash;
+
+  BV (clib_bihash_init) (h, "test", user_buckets, user_memory_size);
+
+  before = clib_time_now (&tm->clib_time);
+
+  for (j = 0; j < 10; j++)
+    {
+      for (i = 1; i <= j * 1000 + 1; i++)
+	{
+	  kv.key = i;
+	  kv.value = 1;
+
+	  BV (clib_bihash_add_del) (h, &kv, 1 /* is_add */ );
+	}
+
+      vec_add1 (cum_times, clib_time_now (&tm->clib_time) - before);
+    }
+
+  for (j = 0; j < vec_len (cum_times); j++)
+    fformat (stdout, "Cum time for %d: %.4f (us)\n", (j + 1) * 1000,
+	     cum_times[j] * 1e6);
+
+  return 0;
+}
+
+void *
+test_bihash_thread_fn (void *arg)
+{
+  BVT (clib_bihash) * h;
+  BVT (clib_bihash_kv) kv;
+  bihash_test_main_t *tm = &bihash_test_main;
+  int i, j;
+  u32 my_thread_index = (u32) (u64) arg;
+
+  while (tm->thread_barrier)
+    ;
+
+  h = &tm->hash;
+
+  for (i = 0; i < tm->ncycles; i++)
+    {
+      for (j = 0; j < tm->nitems; j++)
+	{
+	  kv.key = ((u64) my_thread_index << 32) | (u64) j;
+	  kv.value = ((u64) my_thread_index << 32) | (u64) j;
+	  (void) __atomic_add_fetch (&tm->sequence_number, 1,
+				     __ATOMIC_ACQUIRE);
+	  BV (clib_bihash_add_del) (h, &kv, 1 /* is_add */ );
+	}
+      for (j = 0; j < tm->nitems; j++)
+	{
+	  kv.key = ((u64) my_thread_index << 32) | (u64) j;
+	  kv.value = ((u64) my_thread_index << 32) | (u64) j;
+	  (void) __atomic_add_fetch (&tm->sequence_number, 1,
+				     __ATOMIC_ACQUIRE);
+	  BV (clib_bihash_add_del) (h, &kv, 0 /* is_add */ );
+	}
+    }
+
+  (void) __atomic_sub_fetch (&tm->threads_running, 1, __ATOMIC_ACQUIRE);
+  pthread_exit (0);
+  return (0);			/* not so much */
+}
+
+static clib_error_t *
+test_bihash_threads (bihash_test_main_t * tm)
+{
+  int i;
+  pthread_t handle;
+  BVT (clib_bihash) * h;
+  int rv;
+  f64 before, after, delta;
+
+  h = &tm->hash;
+
+  BV (clib_bihash_init) (h, "test", tm->nbuckets, tm->hash_memory_size);
+
+  tm->thread_barrier = 1;
+
+  /* Start the worker threads */
+  for (i = 0; i < tm->nthreads; i++)
+    {
+      rv = pthread_create (&handle, NULL, test_bihash_thread_fn,
+			   (void *) (u64) i);
+      if (rv)
+	{
+	  clib_unix_warning ("pthread_create returned %d", rv);
+	}
+    }
+  tm->threads_running = i;
+  tm->sequence_number = 0;
+  CLIB_MEMORY_BARRIER ();
+
+  /* start the workers */
+  before = vlib_time_now (tm->vlib_main);
+  tm->thread_barrier = 0;
+
+  while (tm->threads_running > 0)
+    CLIB_PAUSE ();
+
+  after = vlib_time_now (tm->vlib_main);
+  delta = after - before;
+
+  clib_warning ("%lld items in %.2f seconds, %.2f items/sec",
+		(u64) tm->nthreads * (u64) tm->nitems, delta,
+		delta >
+		0.0 ? ((f64) ((u64) tm->nthreads * (u64) tm->nitems)) /
+		delta : 0.0);
+  return 0;
+}
+
+/*
+ * Callback to blow up spectacularly if anthing remains in the table
+ */
+static void
+count_items (BVT (clib_bihash_kv) * kvp, void *notused)
+{
+  _clib_error (CLIB_ERROR_ABORT, 0, 0,
+	       "bihash test FAILED, items left in table!");
+}
+
+static clib_error_t *
+test_bihash (bihash_test_main_t * tm)
+{
+  int i, j;
+  uword *p;
+  uword total_searches;
+  f64 before, delta;
+  BVT (clib_bihash) * h;
+  BVT (clib_bihash_kv) kv;
+  u32 acycle;
+
+  h = &tm->hash;
+
+  BV (clib_bihash_init) (h, "test", tm->nbuckets, tm->hash_memory_size);
+
+  for (acycle = 0; acycle < tm->ncycles; acycle++)
+    {
+      if ((acycle % tm->report_every_n) == 0)
+	{
+	  fformat (stdout, "Cycle %lld out of %lld...\n",
+		   acycle, tm->ncycles);
+
+	  fformat (stdout, "Pick %lld unique %s keys...\n",
+		   tm->nitems, tm->non_random_keys ? "non-random" : "random");
+	}
+
+      for (i = 0; i < tm->nitems; i++)
+	{
+	  u64 rndkey;
+
+	  if (tm->non_random_keys == 0)
+	    {
+
+	    again:
+	      rndkey = random_u64 (&tm->seed);
+
+	      p = hash_get (tm->key_hash, rndkey);
+	      if (p)
+		goto again;
+	    }
+	  else
+	    rndkey = (u64) (i + 1) << 16;
+	  rndkey += acycle;
+
+	  hash_set (tm->key_hash, rndkey, i + 1);
+	  vec_add1 (tm->keys, rndkey);
+	}
+
+
+      if ((acycle % tm->report_every_n) == 0)
+	fformat (stdout, "Add items...\n");
+
+      for (i = 0; i < tm->nitems; i++)
+	{
+	  kv.key = tm->keys[i];
+	  kv.value = i + 1;
+
+	  BV (clib_bihash_add_del) (h, &kv, 1 /* is_add */ );
+
+	  if (tm->verbose > 1)
+	    {
+	      fformat (stdout, "--------------------\n");
+	      fformat (stdout, "After adding key %llu value %lld...\n",
+		       tm->keys[i], (u64) (i + 1));
+	      fformat (stdout, "%U", BV (format_bihash), h,
+		       2 /* very verbose */ );
+	    }
+	}
+
+      if ((acycle % tm->report_every_n) == 0)
+	{
+	  fformat (stdout, "%U", BV (format_bihash), h,
+		   0 /* very verbose */ );
+
+	  fformat (stdout, "Search for items %d times...\n", tm->search_iter);
+	}
+
+      before = clib_time_now (&tm->clib_time);
+
+      for (j = 0; j < tm->search_iter; j++)
+	{
+	  for (i = 0; i < tm->nitems; i++)
+	    {
+	      kv.key = tm->keys[i];
+	      if (BV (clib_bihash_search) (h, &kv, &kv) < 0)
+		if (BV (clib_bihash_search) (h, &kv, &kv) < 0)
+		  clib_warning
+		    ("[%d] search for key %lld failed unexpectedly\n", i,
+		     tm->keys[i]);
+	      if (kv.value != (u64) (i + 1))
+		clib_warning
+		  ("[%d] search for key %lld returned %lld, not %lld\n", i,
+		   tm->keys, kv.value, (u64) (i + 1));
+	    }
+	}
+
+      if ((acycle % tm->report_every_n) == 0)
+	{
+	  delta = clib_time_now (&tm->clib_time) - before;
+	  total_searches = (uword) tm->search_iter * (uword) tm->nitems;
+
+	  if (delta > 0)
+	    fformat (stdout, "%.f searches per second\n",
+		     ((f64) total_searches) / delta);
+
+	  fformat (stdout, "%lld searches in %.6f seconds\n", total_searches,
+		   delta);
+
+	  fformat (stdout, "Standard E-hash search for items %d times...\n",
+		   tm->search_iter);
+	}
+
+      before = clib_time_now (&tm->clib_time);
+
+      for (j = 0; j < tm->search_iter; j++)
+	{
+	  for (i = 0; i < tm->nitems; i++)
+	    {
+	      p = hash_get (tm->key_hash, tm->keys[i]);
+	      if (p == 0 || p[0] != (uword) (i + 1))
+		clib_warning ("ugh, couldn't find %lld\n", tm->keys[i]);
+	    }
+	}
+
+      delta = clib_time_now (&tm->clib_time) - before;
+      total_searches = (uword) tm->search_iter * (uword) tm->nitems;
+
+      if ((acycle % tm->report_every_n) == 0)
+	{
+	  fformat (stdout, "%lld searches in %.6f seconds\n",
+		   total_searches, delta);
+
+	  if (delta > 0)
+	    fformat (stdout, "%.f searches per second\n",
+		     ((f64) total_searches) / delta);
+	  fformat (stdout, "Delete items...\n");
+	}
+
+      for (i = 0; i < tm->nitems; i++)
+	{
+	  int j;
+	  int rv;
+
+	  kv.key = tm->keys[i];
+	  kv.value = (u64) (i + 1);
+	  rv = BV (clib_bihash_add_del) (h, &kv, 0 /* is_add */ );
+
+	  if (rv < 0)
+	    clib_warning ("delete key %lld not ok but should be",
+			  tm->keys[i]);
+
+	  if (tm->careful_delete_tests)
+	    {
+	      for (j = 0; j < tm->nitems; j++)
+		{
+		  kv.key = tm->keys[j];
+		  rv = BV (clib_bihash_search) (h, &kv, &kv);
+		  if (j <= i && rv >= 0)
+		    {
+		      clib_warning
+			("i %d j %d search ok but should not be, value %lld",
+			 i, j, kv.value);
+		    }
+		  if (j > i && rv < 0)
+		    {
+		      clib_warning ("i %d j %d search not ok but should be",
+				    i, j);
+		    }
+		}
+	    }
+	}
+      if ((acycle % tm->report_every_n) == 0)
+	{
+	  struct rusage r_usage;
+	  getrusage (RUSAGE_SELF, &r_usage);
+	  fformat (stdout, "Kernel RSS: %ld bytes\n", r_usage.ru_maxrss);
+	  fformat (stdout, "%U\n", BV (format_bihash), h, 0 /* verbose */ );
+	}
+
+      /* Clean up side-bet hash table and random key vector */
+      hash_free (tm->key_hash);
+      vec_reset_length (tm->keys);
+      /* Recreate hash table if we're going to need it again */
+      if (acycle != (tm->ncycles - 1))
+	tm->key_hash = hash_create (tm->nitems, sizeof (uword));
+    }
+
+  fformat (stdout, "End of run, should be empty...\n");
+
+  fformat (stdout, "%U", BV (format_bihash), h, 0 /* very verbose */ );
+
+  /* ASSERTs if any items remain */
+  BV (clib_bihash_foreach_key_value_pair) (h, count_items, 0);
+
+  return 0;
+}
+
+static clib_error_t *
+test_bihash_command_fn (vlib_main_t * vm,
+			unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  bihash_test_main_t *tm = &bihash_test_main;
+  clib_error_t *error;
+  int which = 0;
+
+  tm->hash_memory_size = 32ULL << 20;
+  tm->nbuckets = 32000;
+  tm->nitems = 100000;
+  tm->ncycles = 10;
+  tm->report_every_n = 50000;
+  tm->seed = 0x1badf00d;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "seed %u", &tm->seed))
+	;
+
+      else if (unformat (input, "nbuckets %d", &tm->nbuckets))
+	;
+      else if (unformat (input, "non-random-keys"))
+	tm->non_random_keys = 1;
+      else if (unformat (input, "nitems %d", &tm->nitems))
+	;
+      else if (unformat (input, "ncycles %d", &tm->ncycles))
+	;
+      else if (unformat (input, "careful %d", &tm->careful_delete_tests))
+	;
+      else if (unformat (input, "verbose %d", &tm->verbose))
+	;
+      else if (unformat (input, "search %d", &tm->search_iter))
+	;
+      else if (unformat (input, "report-every %d", &tm->report_every_n))
+	;
+      else if (unformat (input, "memory-size %U",
+			 unformat_memory_size, &tm->hash_memory_size))
+	;
+      else if (unformat (input, "vec64"))
+	which = 1;
+      else if (unformat (input, "threads %u", &tm->nthreads))
+	which = 2;
+      else if (unformat (input, "verbose"))
+	tm->verbose = 1;
+      else
+	return clib_error_return (0, "unknown input '%U'",
+				  format_unformat_error, input);
+    }
+
+  /* Preallocate hash table, key vector */
+  tm->key_hash = hash_create (tm->nitems, sizeof (uword));
+  vec_validate (tm->keys, tm->nitems - 1);
+  _vec_len (tm->keys) = 0;
+
+  switch (which)
+    {
+    case 0:
+      error = test_bihash (tm);
+      break;
+
+    case 1:
+      error = test_bihash_vec64 (tm);
+      break;
+
+    case 2:
+      error = test_bihash_threads (tm);
+      break;
+
+    default:
+      return clib_error_return (0, "no such test?");
+    }
+
+  return error;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (test_bihash_command, static) =
+{
+  .path = "test bihash",
+  .short_help = "test bihash",
+  .function = test_bihash_command_fn,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+bihash_test_init (vlib_main_t * vm)
+{
+  bihash_test_main_t *tm = &bihash_test_main;
+
+  tm->vlib_main = vm;
+  return (0);
+}
+
+VLIB_INIT_FUNCTION (bihash_test_init);
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/unittest/tcp_test.c b/src/plugins/unittest/tcp_test.c
new file mode 100644
index 00000000000..d26532d4596
--- /dev/null
+++ b/src/plugins/unittest/tcp_test.c
@@ -0,0 +1,1779 @@
+/*
+ * Copyright (c) 2017 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/tcp/tcp.h>
+
+#define TCP_TEST_I(_cond, _comment, _args...)			\
+({								\
+  int _evald = (_cond);						\
+  if (!(_evald)) {						\
+    fformat(stderr, "FAIL:%d: " _comment "\n",			\
+	    __LINE__, ##_args);					\
+  } else {							\
+    fformat(stderr, "PASS:%d: " _comment "\n",			\
+	    __LINE__, ##_args);					\
+  }								\
+  _evald;							\
+})
+
+#define TCP_TEST(_cond, _comment, _args...)			\
+{								\
+    if (!TCP_TEST_I(_cond, _comment, ##_args)) {		\
+	return 1;                                               \
+    }								\
+}
+
+/* *INDENT-OFF* */
+scoreboard_trace_elt_t sb_trace[] = {};
+/* *INDENT-ON* */
+
+static int
+tcp_test_scoreboard_replay (vlib_main_t * vm, unformat_input_t * input)
+{
+  int verbose = 0;
+  tcp_connection_t _tc, *tc = &_tc;
+  u8 *s = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "detail"))
+	verbose = 1;
+      else
+	{
+	  clib_error_t *e = clib_error_return
+	    (0, "unknown input `%U'", format_unformat_error, input);
+	  clib_error_report (e);
+	  return -1;
+	}
+    }
+
+#if TCP_SCOREBOARD_TRACE
+  tc->sack_sb.trace = sb_trace;
+#endif
+  s = tcp_scoreboard_replay (s, tc, verbose);
+  vlib_cli_output (vm, "%v", s);
+  return 0;
+}
+
+static int
+tcp_test_sack_rx (vlib_main_t * vm, unformat_input_t * input)
+{
+  tcp_connection_t _tc, *tc = &_tc;
+  sack_scoreboard_t *sb = &tc->sack_sb;
+  sack_block_t *sacks = 0, block;
+  sack_scoreboard_hole_t *hole;
+  int i, verbose = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	verbose = 1;
+      else if (unformat (input, "replay"))
+	return tcp_test_scoreboard_replay (vm, input);
+    }
+
+  memset (tc, 0, sizeof (*tc));
+
+  tc->snd_una = 0;
+  tc->snd_una_max = 1000;
+  tc->snd_nxt = 1000;
+  tc->rcv_opts.flags |= TCP_OPTS_FLAG_SACK;
+  scoreboard_init (&tc->sack_sb);
+
+  for (i = 0; i < 1000 / 100; i++)
+    {
+      block.start = i * 100;
+      block.end = (i + 1) * 100;
+      vec_add1 (sacks, block);
+    }
+
+  /*
+   * Inject even blocks
+   */
+
+  for (i = 0; i < 1000 / 200; i++)
+    {
+      vec_add1 (tc->rcv_opts.sacks, sacks[i * 2]);
+    }
+  tc->rcv_opts.n_sack_blocks = vec_len (tc->rcv_opts.sacks);
+  tcp_rcv_sacks (tc, 0);
+
+  if (verbose)
+    vlib_cli_output (vm, "sb after even blocks:\n%U", format_tcp_scoreboard,
+		     sb);
+
+  TCP_TEST ((pool_elts (sb->holes) == 5),
+	    "scoreboard has %d elements", pool_elts (sb->holes));
+
+  /* First SACK block should be rejected */
+  hole = scoreboard_first_hole (sb);
+  TCP_TEST ((hole->start == 0 && hole->end == 200),
+	    "first hole start %u end %u", hole->start, hole->end);
+  hole = scoreboard_last_hole (sb);
+  TCP_TEST ((hole->start == 900 && hole->end == 1000),
+	    "last hole start %u end %u", hole->start, hole->end);
+  TCP_TEST ((sb->sacked_bytes == 400), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->snd_una_adv == 0), "snd_una_adv %u", sb->snd_una_adv);
+  TCP_TEST ((sb->last_sacked_bytes == 400),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+  TCP_TEST ((sb->high_sacked == 900), "max byte sacked %u", sb->high_sacked);
+  /*
+   * Inject odd blocks
+   */
+
+  vec_reset_length (tc->rcv_opts.sacks);
+  for (i = 0; i < 1000 / 200; i++)
+    {
+      vec_add1 (tc->rcv_opts.sacks, sacks[i * 2 + 1]);
+    }
+  tc->rcv_opts.n_sack_blocks = vec_len (tc->rcv_opts.sacks);
+  tcp_rcv_sacks (tc, 0);
+
+  if (verbose)
+    vlib_cli_output (vm, "sb after odd blocks:\n%U", format_tcp_scoreboard,
+		     sb);
+
+  hole = scoreboard_first_hole (sb);
+  TCP_TEST ((pool_elts (sb->holes) == 1),
+	    "scoreboard has %d holes", pool_elts (sb->holes));
+  TCP_TEST ((hole->start == 0 && hole->end == 100),
+	    "first hole start %u end %u", hole->start, hole->end);
+  TCP_TEST ((sb->sacked_bytes == 900), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->snd_una_adv == 0), "snd_una_adv %u", sb->snd_una_adv);
+  TCP_TEST ((sb->high_sacked == 1000), "max sacked byte %u", sb->high_sacked);
+  TCP_TEST ((sb->last_sacked_bytes == 500),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+
+  /*
+   *  Ack until byte 100, all bytes are now acked + sacked
+   */
+  tcp_rcv_sacks (tc, 100);
+  if (verbose)
+    vlib_cli_output (vm, "ack until byte 100:\n%U", format_tcp_scoreboard,
+		     sb);
+
+  TCP_TEST ((pool_elts (sb->holes) == 0),
+	    "scoreboard has %d elements", pool_elts (sb->holes));
+  TCP_TEST ((sb->snd_una_adv == 900),
+	    "snd_una_adv after ack %u", sb->snd_una_adv);
+  TCP_TEST ((sb->high_sacked == 1000), "max sacked byte %u", sb->high_sacked);
+  TCP_TEST ((sb->sacked_bytes == 0), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->last_sacked_bytes == 0),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+
+  /*
+   * Add new block
+   */
+
+  vec_reset_length (tc->rcv_opts.sacks);
+
+  block.start = 1200;
+  block.end = 1300;
+  vec_add1 (tc->rcv_opts.sacks, block);
+
+  if (verbose)
+    vlib_cli_output (vm, "add [1200, 1300]:\n%U", format_tcp_scoreboard, sb);
+  tc->snd_una_max = 1500;
+  tc->snd_una = 1000;
+  tc->snd_nxt = 1500;
+  tcp_rcv_sacks (tc, 1000);
+
+  if (verbose)
+    vlib_cli_output (vm, "sb snd_una_max 1500, snd_una 1000:\n%U",
+		     format_tcp_scoreboard, sb);
+
+  TCP_TEST ((sb->snd_una_adv == 0),
+	    "snd_una_adv after ack %u", sb->snd_una_adv);
+  TCP_TEST ((pool_elts (sb->holes) == 2),
+	    "scoreboard has %d holes", pool_elts (sb->holes));
+  hole = scoreboard_first_hole (sb);
+  TCP_TEST ((hole->start == 1000 && hole->end == 1200),
+	    "first hole start %u end %u", hole->start, hole->end);
+  TCP_TEST ((sb->snd_una_adv == 0),
+	    "snd_una_adv after ack %u", sb->snd_una_adv);
+  TCP_TEST ((sb->high_sacked == 1300), "max sacked byte %u", sb->high_sacked);
+  hole = scoreboard_last_hole (sb);
+  TCP_TEST ((hole->start == 1300 && hole->end == 1500),
+	    "last hole start %u end %u", hole->start, hole->end);
+  TCP_TEST ((sb->sacked_bytes == 100), "sacked bytes %d", sb->sacked_bytes);
+
+  /*
+   * Ack first hole
+   */
+
+  vec_reset_length (tc->rcv_opts.sacks);
+  tcp_rcv_sacks (tc, 1200);
+
+  if (verbose)
+    vlib_cli_output (vm, "sb ack up to byte 1200:\n%U", format_tcp_scoreboard,
+		     sb);
+
+  TCP_TEST ((sb->snd_una_adv == 100),
+	    "snd_una_adv after ack %u", sb->snd_una_adv);
+  TCP_TEST ((sb->sacked_bytes == 0), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((pool_elts (sb->holes) == 1),
+	    "scoreboard has %d elements", pool_elts (sb->holes));
+  hole = scoreboard_first_hole (sb);
+  TCP_TEST ((hole->prev == TCP_INVALID_SACK_HOLE_INDEX
+	     && hole->next == TCP_INVALID_SACK_HOLE_INDEX), "hole is valid");
+  TCP_TEST ((sb->last_bytes_delivered == 100), "last bytes delivered %d",
+	    sb->last_bytes_delivered);
+
+  /*
+   * Add some more blocks and then remove all
+   */
+  vec_reset_length (tc->rcv_opts.sacks);
+  tc->snd_una += sb->snd_una_adv;
+  tc->snd_una_max = 1900;
+  for (i = 0; i < 5; i++)
+    {
+      block.start = i * 100 + 1200;
+      block.end = (i + 1) * 100 + 1200;
+      vec_add1 (tc->rcv_opts.sacks, block);
+    }
+  tcp_rcv_sacks (tc, 1900);
+
+  scoreboard_clear (sb);
+  if (verbose)
+    vlib_cli_output (vm, "sb cleared all:\n%U", format_tcp_scoreboard, sb);
+
+  TCP_TEST ((pool_elts (sb->holes) == 0),
+	    "number of holes %d", pool_elts (sb->holes));
+  TCP_TEST ((sb->head == TCP_INVALID_SACK_HOLE_INDEX), "head %u", sb->head);
+  TCP_TEST ((sb->tail == TCP_INVALID_SACK_HOLE_INDEX), "tail %u", sb->tail);
+
+  /*
+   * Re-inject odd blocks and ack them all
+   */
+
+  tc->snd_una = 0;
+  tc->snd_una_max = 1000;
+  tc->snd_nxt = 1000;
+  for (i = 0; i < 5; i++)
+    {
+      vec_add1 (tc->rcv_opts.sacks, sacks[i * 2 + 1]);
+    }
+  tc->rcv_opts.n_sack_blocks = vec_len (tc->rcv_opts.sacks);
+  tcp_rcv_sacks (tc, 0);
+  if (verbose)
+    vlib_cli_output (vm, "sb added odd blocks and ack [0, 950]:\n%U",
+		     format_tcp_scoreboard, sb);
+
+  tcp_rcv_sacks (tc, 950);
+
+  if (verbose)
+    vlib_cli_output (vm, "sb added odd blocks and ack [0, 950]:\n%U",
+		     format_tcp_scoreboard, sb);
+
+  TCP_TEST ((pool_elts (sb->holes) == 0),
+	    "scoreboard has %d elements", pool_elts (sb->holes));
+  TCP_TEST ((sb->snd_una_adv == 50), "snd_una_adv %u", sb->snd_una_adv);
+  TCP_TEST ((sb->sacked_bytes == 0), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->last_sacked_bytes == 0),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+
+  /*
+   * Inject one block, ack it and overlap hole
+   */
+
+  tc->snd_una = 0;
+  tc->snd_una_max = 1000;
+  tc->snd_nxt = 1000;
+
+  block.start = 100;
+  block.end = 500;
+  vec_add1 (tc->rcv_opts.sacks, block);
+  tc->rcv_opts.n_sack_blocks = vec_len (tc->rcv_opts.sacks);
+
+  tcp_rcv_sacks (tc, 0);
+
+  if (verbose)
+    vlib_cli_output (vm, "sb added [100, 500]:\n%U",
+		     format_tcp_scoreboard, sb);
+
+  tcp_rcv_sacks (tc, 800);
+
+  if (verbose)
+    vlib_cli_output (vm, "sb ack [0, 800]:\n%U", format_tcp_scoreboard, sb);
+
+  TCP_TEST ((pool_elts (sb->holes) == 1),
+	    "scoreboard has %d elements", pool_elts (sb->holes));
+  TCP_TEST ((sb->snd_una_adv == 0), "snd_una_adv %u", sb->snd_una_adv);
+  TCP_TEST ((sb->sacked_bytes == 0), "sacked bytes %d", sb->sacked_bytes);
+  TCP_TEST ((sb->last_sacked_bytes == 0),
+	    "last sacked bytes %d", sb->last_sacked_bytes);
+  TCP_TEST ((sb->last_bytes_delivered == 400),
+	    "last bytes delivered %d", sb->last_bytes_delivered);
+
+  /*
+   * One hole close to head, patch head, split in two and start acking
+   * the lowest part
+   */
+  scoreboard_clear (sb);
+  tc->snd_una = 0;
+  tc->snd_una_max = 1000;
+  tc->snd_nxt = 1000;
+
+  block.start = 500;
+  block.end = 1000;
+  vec_add1 (tc->rcv_opts.sacks, block);
+  tc->rcv_opts.n_sack_blocks = vec_len (tc->rcv_opts.sacks);
+
+  tcp_rcv_sacks (tc, 0);
+  if (verbose)
+    vlib_cli_output (vm, "sb added [500, 1000]:\n%U",
+		     format_tcp_scoreboard, sb);
+
+  vec_reset_length (tc->rcv_opts.sacks);
+  block.start = 300;
+  block.end = 400;
+  vec_add1 (tc->rcv_opts.sacks, block);
+  tc->rcv_opts.n_sack_blocks = vec_len (tc->rcv_opts.sacks);
+  tcp_rcv_sacks (tc, 100);
+  if (verbose)
+    vlib_cli_output (vm, "sb added [0, 100] [300, 400]:\n%U",
+		     format_tcp_scoreboard, sb);
+  TCP_TEST ((pool_elts (sb->holes) == 2),
+	    "scoreboard has %d elements", pool_elts (sb->holes));
+
+  tc->snd_una = 100;
+  tcp_rcv_sacks (tc, 200);
+  tcp_rcv_sacks (tc, 300);
+  if (verbose)
+    vlib_cli_output (vm, "sb added [0, 300]:\n%U", format_tcp_scoreboard, sb);
+  TCP_TEST ((sb->sacked_bytes == 500), "sacked bytes %d", sb->sacked_bytes);
+
+  return 0;
+}
+
+static int
+tcp_test_sack_tx (vlib_main_t * vm, unformat_input_t * input)
+{
+  tcp_connection_t _tc, *tc = &_tc;
+  sack_block_t *sacks;
+  int i, verbose = 0, expected;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	verbose = 1;
+      else
+	{
+	  vlib_cli_output (vm, "parse error: '%U'", format_unformat_error,
+			   input);
+	  return -1;
+	}
+    }
+
+  memset (tc, 0, sizeof (*tc));
+
+  /*
+   * Add odd sack block pairs
+   */
+  for (i = 1; i < 10; i += 2)
+    {
+      tcp_update_sack_list (tc, i * 100, (i + 1) * 100);
+    }
+
+  TCP_TEST ((vec_len (tc->snd_sacks) == 5), "sack blocks %d expected %d",
+	    vec_len (tc->snd_sacks), 5);
+  TCP_TEST ((tc->snd_sacks[0].start = 900),
+	    "first sack block start %u expected %u", tc->snd_sacks[0].start,
+	    900);
+
+  /*
+   * Try to add one extra
+   */
+  sacks = vec_dup (tc->snd_sacks);
+
+  tcp_update_sack_list (tc, 1100, 1200);
+  if (verbose)
+    vlib_cli_output (vm, "add new segment [1100, 1200]\n%U",
+		     format_tcp_sacks, tc);
+  expected = 5 < TCP_MAX_SACK_BLOCKS ? 6 : 5;
+  TCP_TEST ((vec_len (tc->snd_sacks) == expected),
+	    "sack blocks %d expected %d", vec_len (tc->snd_sacks), expected);
+  TCP_TEST ((tc->snd_sacks[0].start == 1100),
+	    "first sack block start %u expected %u", tc->snd_sacks[0].start,
+	    1100);
+
+  /* restore */
+  vec_free (tc->snd_sacks);
+  tc->snd_sacks = sacks;
+
+  /*
+   * Overlap first 2 segment
+   */
+  tc->rcv_nxt = 300;
+  tcp_update_sack_list (tc, 300, 300);
+  if (verbose)
+    vlib_cli_output (vm, "overlap first 2 segments:\n%U",
+		     format_tcp_sacks, tc);
+  TCP_TEST ((vec_len (tc->snd_sacks) == 3), "sack blocks %d expected %d",
+	    vec_len (tc->snd_sacks), 3);
+  TCP_TEST ((tc->snd_sacks[0].start == 900),
+	    "first sack block start %u expected %u", tc->snd_sacks[0].start,
+	    500);
+
+  /*
+   * Add a new segment
+   */
+  tcp_update_sack_list (tc, 1100, 1200);
+  if (verbose)
+    vlib_cli_output (vm, "add new segment [1100, 1200]\n%U",
+		     format_tcp_sacks, tc);
+  TCP_TEST ((vec_len (tc->snd_sacks) == 4), "sack blocks %d expected %d",
+	    vec_len (tc->snd_sacks), 4);
+  TCP_TEST ((tc->snd_sacks[0].start == 1100),
+	    "first sack block start %u expected %u", tc->snd_sacks[0].start,
+	    1100);
+
+  /*
+   * Join middle segments
+   */
+  tcp_update_sack_list (tc, 800, 900);
+  if (verbose)
+    vlib_cli_output (vm, "join middle segments [800, 900]\n%U",
+		     format_tcp_sacks, tc);
+
+  TCP_TEST ((vec_len (tc->snd_sacks) == 3), "sack blocks %d expected %d",
+	    vec_len (tc->snd_sacks), 3);
+  TCP_TEST ((tc->snd_sacks[0].start == 700),
+	    "first sack block start %u expected %u", tc->snd_sacks[0].start,
+	    1100);
+
+  /*
+   * Advance rcv_nxt to overlap all
+   */
+  tc->rcv_nxt = 1200;
+  tcp_update_sack_list (tc, 1200, 1200);
+  if (verbose)
+    vlib_cli_output (vm, "advance rcv_nxt to 1200\n%U", format_tcp_sacks, tc);
+  TCP_TEST ((vec_len (tc->snd_sacks) == 0), "sack blocks %d expected %d",
+	    vec_len (tc->snd_sacks), 0);
+
+
+  /*
+   * Add 2 blocks, overwrite first and update rcv_nxt to also remove it
+   */
+
+  vec_reset_length (tc->snd_sacks);
+  tc->rcv_nxt = 0;
+
+  tcp_update_sack_list (tc, 100, 200);
+  tcp_update_sack_list (tc, 300, 400);
+
+  if (verbose)
+    vlib_cli_output (vm, "add [100, 200] [300, 400]\n%U",
+		     format_tcp_sacks, tc);
+  TCP_TEST ((vec_len (tc->snd_sacks) == 2),
+	    "sack blocks %d expected %d", vec_len (tc->snd_sacks), 2);
+  TCP_TEST ((tc->snd_sacks[0].start == 300),
+	    "first sack block start %u expected %u", tc->snd_sacks[0].start,
+	    300);
+
+  tc->rcv_nxt = 100;
+  tcp_update_sack_list (tc, 100, 100);
+  if (verbose)
+    vlib_cli_output (vm, "add [100, 200] rcv_nxt = 100\n%U",
+		     format_tcp_sacks, tc);
+  TCP_TEST ((vec_len (tc->snd_sacks) == 1),
+	    "sack blocks %d expected %d", vec_len (tc->snd_sacks), 1);
+  TCP_TEST ((tc->snd_sacks[0].start == 300),
+	    "first sack block start %u expected %u", tc->snd_sacks[0].start,
+	    300);
+  return 0;
+}
+
+static int
+tcp_test_sack (vlib_main_t * vm, unformat_input_t * input)
+{
+  int res = 0;
+
+  /* Run all tests */
+  if (unformat_check_input (input) == UNFORMAT_END_OF_INPUT)
+    {
+      if (tcp_test_sack_tx (vm, input))
+	{
+	  return -1;
+	}
+
+      if (tcp_test_sack_rx (vm, input))
+	{
+	  return -1;
+	}
+    }
+  else
+    {
+      if (unformat (input, "tx"))
+	{
+	  res = tcp_test_sack_tx (vm, input);
+	}
+      else if (unformat (input, "rx"))
+	{
+	  res = tcp_test_sack_rx (vm, input);
+	}
+    }
+
+  return res;
+}
+
+
+typedef struct
+{
+  u32 offset;
+  u32 len;
+} test_pattern_t;
+
+/* *INDENT-OFF* */
+test_pattern_t test_pattern[] = {
+  {380, 8}, {768, 8}, {1156, 8}, {1544, 8}, {1932, 8}, {2320, 8}, {2708, 8},
+  {2992, 8}, {372, 8}, {760, 8}, {1148, 8}, {1536, 8}, {1924, 8}, {2312, 8},
+  {2700, 8}, {2984, 8}, {364, 8}, {752, 8}, {1140, 8}, {1528, 8}, {1916, 8},
+  {2304, 8}, {2692, 8}, {2976, 8}, {356, 8}, {744, 8}, {1132, 8}, {1520, 8},
+  {1908, 8}, {2296, 8}, {2684, 8}, {2968, 8}, {348, 8}, {736, 8}, {1124, 8},
+  {1512, 8}, {1900, 8}, {2288, 8}, {2676, 8}, {2960, 8}, {340, 8}, {728, 8},
+  {1116, 8}, {1504, 8}, {1892, 8}, {2280, 8}, {2668, 8}, {2952, 8}, {332, 8},
+  {720, 8}, {1108, 8}, {1496, 8}, {1884, 8}, {2272, 8}, {2660, 8}, {2944, 8},
+  {324, 8}, {712, 8}, {1100, 8}, {1488, 8}, {1876, 8}, {2264, 8}, {2652, 8},
+  {2936, 8}, {316, 8}, {704, 8}, {1092, 8}, {1480, 8}, {1868, 8}, {2256, 8},
+  {2644, 8}, {2928, 8}, {308, 8}, {696, 8}, {1084, 8}, {1472, 8}, {1860, 8},
+  {2248, 8}, {2636, 8}, {2920, 8}, {300, 8}, {688, 8}, {1076, 8}, {1464, 8},
+  {1852, 8}, {2240, 8}, {2628, 8}, {2912, 8}, {292, 8}, {680, 8}, {1068, 8},
+  {1456, 8}, {1844, 8}, {2232, 8}, {2620, 8}, {2904, 8}, {284, 8}, {672, 8},
+  {1060, 8}, {1448, 8}, {1836, 8}, {2224, 8}, {2612, 8}, {2896, 8}, {276, 8},
+  {664, 8}, {1052, 8}, {1440, 8}, {1828, 8},  {2216, 8}, {2604, 8}, {2888, 8},
+  {268, 8}, {656, 8}, {1044, 8}, {1432, 8}, {1820, 8}, {2208, 8}, {2596, 8},
+  {2880, 8}, {260, 8}, {648, 8}, {1036, 8}, {1424, 8}, {1812, 8}, {2200, 8},
+  {2588, 8}, {2872, 8}, {252, 8}, {640, 8}, {1028, 8}, {1416, 8}, {1804, 8},
+  {2192, 8}, {2580, 8}, {2864, 8}, {244, 8}, {632, 8}, {1020, 8}, {1408, 8},
+  {1796, 8}, {2184, 8}, {2572, 8}, {2856, 8}, {236, 8}, {624, 8}, {1012, 8},
+  {1400, 8}, {1788, 8}, {2176, 8}, {2564, 8}, {2848, 8}, {228, 8}, {616, 8},
+  {1004, 8}, {1392, 8}, {1780, 8}, {2168, 8}, {2556, 8}, {2840, 8}, {220, 8},
+  {608, 8}, {996, 8}, {1384, 8}, {1772, 8}, {2160, 8}, {2548, 8}, {2832, 8},
+  {212, 8}, {600, 8}, {988, 8}, {1376, 8}, {1764, 8}, {2152, 8}, {2540, 8},
+  {2824, 8}, {204, 8}, {592, 8}, {980, 8}, {1368, 8}, {1756, 8}, {2144, 8},
+  {2532, 8}, {2816, 8}, {196, 8}, {584, 8}, {972, 8}, {1360, 8}, {1748, 8},
+  {2136, 8}, {2524, 8}, {2808, 8}, {188, 8}, {576, 8}, {964, 8}, {1352, 8},
+  {1740, 8}, {2128, 8}, {2516, 8}, {2800, 8}, {180, 8}, {568, 8}, {956, 8},
+  {1344, 8}, {1732, 8}, {2120, 8}, {2508, 8}, {2792, 8}, {172, 8}, {560, 8},
+  {948, 8}, {1336, 8}, {1724, 8}, {2112, 8}, {2500, 8}, {2784, 8}, {164, 8},
+  {552, 8}, {940, 8}, {1328, 8}, {1716, 8}, {2104, 8}, {2492, 8}, {2776, 8},
+  {156, 8}, {544, 8}, {932, 8}, {1320, 8}, {1708, 8}, {2096, 8}, {2484, 8},
+  {2768, 8}, {148, 8}, {536, 8}, {924, 8}, {1312, 8}, {1700, 8}, {2088, 8},
+  {2476, 8}, {2760, 8}, {140, 8}, {528, 8}, {916, 8}, {1304, 8}, {1692, 8},
+  {2080, 8}, {2468, 8}, {2752, 8}, {132, 8}, {520, 8}, {908, 8}, {1296, 8},
+  {1684, 8}, {2072, 8}, {2460, 8}, {2744, 8}, {124, 8}, {512, 8}, {900, 8},
+  {1288, 8}, {1676, 8}, {2064, 8}, {2452, 8}, {2736, 8}, {116, 8}, {504, 8},
+  {892, 8}, {1280, 8}, {1668, 8}, {2056, 8}, {2444, 8}, {2728, 8}, {108, 8},
+  {496, 8}, {884, 8}, {1272, 8}, {1660, 8}, {2048, 8}, {2436, 8}, {2720, 8},
+  {100, 8}, {488, 8}, {876, 8}, {1264, 8}, {1652, 8}, {2040, 8}, {2428, 8},
+  {2716, 4}, {92, 8}, {480, 8}, {868, 8}, {1256, 8}, {1644, 8}, {2032, 8},
+  {2420, 8}, {84, 8}, {472, 8}, {860, 8}, {1248, 8}, {1636, 8}, {2024, 8},
+  {2412, 8}, {76, 8}, {464, 8}, {852, 8}, {1240, 8}, {1628, 8}, {2016, 8},
+  {2404, 8}, {68, 8}, {456, 8}, {844, 8}, {1232, 8}, {1620, 8}, {2008, 8},
+  {2396, 8}, {60, 8}, {448, 8}, {836, 8}, {1224, 8}, {1612, 8}, {2000, 8},
+  {2388, 8}, {52, 8}, {440, 8}, {828, 8}, {1216, 8}, {1604, 8}, {1992, 8},
+  {2380, 8}, {44, 8}, {432, 8}, {820, 8}, {1208, 8}, {1596, 8}, {1984, 8},
+  {2372, 8}, {36, 8}, {424, 8}, {812, 8}, {1200, 8}, {1588, 8}, {1976, 8},
+  {2364, 8}, {28, 8}, {416, 8}, {804, 8}, {1192, 8}, {1580, 8}, {1968, 8},
+  {2356, 8}, {20, 8}, {408, 8}, {796, 8}, {1184, 8}, {1572, 8}, {1960, 8},
+  {2348, 8}, {12, 8}, {400, 8}, {788, 8}, {1176, 8}, {1564, 8}, {1952, 8},
+  {2340, 8}, {4, 8}, {392, 8}, {780, 8}, {1168, 8}, {1556, 8}, {1944, 8},
+  {2332, 8},
+  /* missing from original data set */
+  {388, 4}, {776, 4}, {1164, 4}, {1552, 4}, {1940, 4}, {2328, 4},
+};
+/* *INDENT-ON* */
+
+int
+pattern_cmp (const void *arg1, const void *arg2)
+{
+  test_pattern_t *a1 = (test_pattern_t *) arg1;
+  test_pattern_t *a2 = (test_pattern_t *) arg2;
+
+  if (a1->offset < a2->offset)
+    return -1;
+  else if (a1->offset > a2->offset)
+    return 1;
+  return 0;
+}
+
+static u8
+fifo_validate_pattern (vlib_main_t * vm, test_pattern_t * pattern,
+		       u32 pattern_length)
+{
+  test_pattern_t *tp = pattern;
+  int i;
+
+  /* Go through the pattern and make 100% sure it's sane */
+  for (i = 0; i < pattern_length - 1; i++)
+    {
+      if (tp->offset + tp->len != (tp + 1)->offset)
+	{
+	  vlib_cli_output (vm, "[%d] missing {%d, %d}", i,
+			   (tp->offset + tp->len),
+			   (tp + 1)->offset - (tp->offset + tp->len));
+	  return 0;
+	}
+      tp++;
+    }
+  return 1;
+}
+
+static test_pattern_t *
+fifo_get_validate_pattern (vlib_main_t * vm, test_pattern_t * test_data,
+			   u32 test_data_len)
+{
+  test_pattern_t *validate_pattern = 0;
+
+  /* Validate, and try segments in order... */
+  vec_validate (validate_pattern, test_data_len - 1);
+  memcpy (validate_pattern, test_data,
+	  test_data_len * sizeof (test_pattern_t));
+  qsort ((u8 *) validate_pattern, test_data_len, sizeof (test_pattern_t),
+	 pattern_cmp);
+
+  if (fifo_validate_pattern (vm, validate_pattern, test_data_len) == 0)
+    return 0;
+
+  return validate_pattern;
+}
+
+static svm_fifo_t *
+fifo_prepare (u32 fifo_size)
+{
+  svm_fifo_t *f;
+  f = svm_fifo_create (fifo_size);
+
+  /* Paint fifo data vector with -1's */
+  memset (f->data, 0xFF, fifo_size);
+
+  return f;
+}
+
+static int
+compare_data (u8 * data1, u8 * data2, u32 start, u32 len, u32 * index)
+{
+  int i;
+
+  for (i = start; i < len; i++)
+    {
+      if (data1[i] != data2[i])
+	{
+	  *index = i;
+	  return 1;
+	}
+    }
+  return 0;
+}
+
+int
+tcp_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
+{
+  svm_fifo_t *f;
+  u32 fifo_size = 1 << 20;
+  u32 *test_data = 0;
+  u32 offset;
+  int i, rv, verbose = 0;
+  u32 data_word, test_data_len, j;
+  ooo_segment_t *ooo_seg;
+  u8 *data, *s, *data_buf = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	verbose = 1;
+    }
+
+  test_data_len = fifo_size / sizeof (u32);
+  vec_validate (test_data, test_data_len - 1);
+
+  for (i = 0; i < vec_len (test_data); i++)
+    test_data[i] = i;
+
+  f = fifo_prepare (fifo_size);
+
+  /*
+   * Enqueue an initial (un-dequeued) chunk
+   */
+  rv = svm_fifo_enqueue_nowait (f, sizeof (u32), (u8 *) test_data);
+  TCP_TEST ((rv == sizeof (u32)), "enqueued %d", rv);
+  TCP_TEST ((f->tail == 4), "fifo tail %u", f->tail);
+
+  /*
+   * Create 3 chunks in the future. The offsets are relative
+   * to the current fifo tail
+   */
+  for (i = 0; i < 3; i++)
+    {
+      offset = (2 * i + 1) * sizeof (u32) - f->tail;
+      data = (u8 *) (test_data + (2 * i + 1));
+      if (i == 0)
+	{
+	  rv = svm_fifo_enqueue_nowait (f, sizeof (u32), data);
+	  rv = rv > 0 ? 0 : rv;
+	}
+      else
+	rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
+      if (verbose)
+	vlib_cli_output (vm, "add [%d] [%d, %d]", 2 * i + 1, offset,
+			 offset + sizeof (u32));
+      if (rv)
+	{
+	  clib_warning ("enqueue returned %d", rv);
+	  goto err;
+	}
+    }
+
+  if (verbose)
+    vlib_cli_output (vm, "fifo after odd segs: %U", format_svm_fifo, f, 1);
+
+  TCP_TEST ((f->tail == 8), "fifo tail %u", f->tail);
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 2),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+
+  /*
+   * Try adding a completely overlapped segment
+   */
+  offset = 3 * sizeof (u32) - f->tail;
+  data = (u8 *) (test_data + 3);
+  rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
+  if (rv)
+    {
+      clib_warning ("enqueue returned %d", rv);
+      goto err;
+    }
+
+  if (verbose)
+    vlib_cli_output (vm, "fifo after overlap seg: %U", format_svm_fifo, f, 1);
+
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 2),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+
+  /*
+   * Make sure format functions are not buggy
+   */
+  s = format (0, "%U", format_svm_fifo, f, 2);
+  vec_free (s);
+
+  /*
+   * Paint some of missing data backwards
+   */
+  for (i = 3; i > 1; i--)
+    {
+      offset = (2 * i + 0) * sizeof (u32) - f->tail;
+      data = (u8 *) (test_data + (2 * i + 0));
+      rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
+      if (verbose)
+	vlib_cli_output (vm, "add [%d] [%d, %d]", 2 * i, offset,
+			 offset + sizeof (u32));
+      if (rv)
+	{
+	  clib_warning ("enqueue returned %d", rv);
+	  goto err;
+	}
+    }
+
+  if (verbose)
+    vlib_cli_output (vm, "fifo before missing link: %U", format_svm_fifo, f,
+		     1);
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 1),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+  ooo_seg = svm_fifo_first_ooo_segment (f);
+  TCP_TEST ((ooo_seg->start == 12),
+	    "first ooo seg position %u", ooo_seg->start);
+  TCP_TEST ((ooo_seg->length == 16),
+	    "first ooo seg length %u", ooo_seg->length);
+
+  /*
+   * Enqueue the missing u32
+   */
+  rv = svm_fifo_enqueue_nowait (f, sizeof (u32), (u8 *) (test_data + 2));
+  if (verbose)
+    vlib_cli_output (vm, "fifo after missing link: %U", format_svm_fifo, f,
+		     1);
+  TCP_TEST ((rv == 20), "bytes to be enqueued %u", rv);
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 0),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+
+  /*
+   * Collect results
+   */
+  for (i = 0; i < 7; i++)
+    {
+      rv = svm_fifo_dequeue_nowait (f, sizeof (u32), (u8 *) & data_word);
+      if (rv != sizeof (u32))
+	{
+	  clib_warning ("bytes dequeues %u", rv);
+	  goto err;
+	}
+      if (data_word != test_data[i])
+	{
+	  clib_warning ("recovered [%d] %d not %d", i, data_word,
+			test_data[i]);
+	  goto err;
+	}
+    }
+
+  /*
+   * Test segment overlaps: last ooo segment overlaps all
+   */
+  svm_fifo_free (f);
+  f = fifo_prepare (fifo_size);
+
+  for (i = 0; i < 4; i++)
+    {
+      offset = (2 * i + 1) * sizeof (u32) - f->tail;
+      data = (u8 *) (test_data + (2 * i + 1));
+      rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
+      if (verbose)
+	vlib_cli_output (vm, "add [%d] [%d, %d]", 2 * i + 1, offset,
+			 offset + sizeof (u32));
+      if (rv)
+	{
+	  clib_warning ("enqueue returned %d", rv);
+	  goto err;
+	}
+    }
+
+  rv = svm_fifo_enqueue_with_offset (f, 8 - f->tail, 21, data);
+  TCP_TEST ((rv == 0), "ooo enqueued %u", rv);
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 1),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+
+  vec_validate (data_buf, vec_len (data));
+  svm_fifo_peek (f, 0, vec_len (data), data_buf);
+  if (compare_data (data_buf, data, 8, vec_len (data), &j))
+    {
+      TCP_TEST (0, "[%d] peeked %u expected %u", j, data_buf[j], data[j]);
+    }
+  vec_reset_length (data_buf);
+
+  /*
+   * Test segment overlaps: enqueue and overlap ooo segments
+   */
+  svm_fifo_free (f);
+  f = fifo_prepare (fifo_size);
+
+  for (i = 0; i < 4; i++)
+    {
+      offset = (2 * i + 1) * sizeof (u32) - f->tail;
+      data = (u8 *) (test_data + (2 * i + 1));
+      rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
+      if (verbose)
+	vlib_cli_output (vm, "add [%d] [%d, %d]", 2 * i + 1, offset,
+			 offset + sizeof (u32));
+      if (rv)
+	{
+	  clib_warning ("enqueue returned %d", rv);
+	  goto err;
+	}
+    }
+
+  if (verbose)
+    vlib_cli_output (vm, "fifo after enqueue: %U", format_svm_fifo, f, 1);
+
+  rv = svm_fifo_enqueue_nowait (f, 29, data);
+  if (verbose)
+    vlib_cli_output (vm, "fifo after enqueueing 29: %U", format_svm_fifo, f,
+		     1);
+  TCP_TEST ((rv == 32), "ooo enqueued %u", rv);
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 0),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+
+  vec_validate (data_buf, vec_len (data));
+  svm_fifo_peek (f, 0, vec_len (data), data_buf);
+  if (compare_data (data_buf, data, 0, vec_len (data), &j))
+    {
+      TCP_TEST (0, "[%d] peeked %u expected %u", j, data_buf[j], data[j]);
+    }
+
+  /* Try to peek beyond the data */
+  rv = svm_fifo_peek (f, svm_fifo_max_dequeue (f), vec_len (data), data_buf);
+  TCP_TEST ((rv == 0), "peeked %u expected 0", rv);
+
+  vec_free (data_buf);
+  svm_fifo_free (f);
+  vec_free (test_data);
+
+  return 0;
+
+err:
+  svm_fifo_free (f);
+  vec_free (test_data);
+  return -1;
+}
+
+static int
+tcp_test_fifo2 (vlib_main_t * vm)
+{
+  svm_fifo_t *f;
+  u32 fifo_size = 1 << 20;
+  int i, rv, test_data_len;
+  u64 data64;
+  test_pattern_t *tp, *vp, *test_data;
+  ooo_segment_t *ooo_seg;
+
+  test_data = test_pattern;
+  test_data_len = ARRAY_LEN (test_pattern);
+
+  vp = fifo_get_validate_pattern (vm, test_data, test_data_len);
+
+  /* Create a fifo */
+  f = fifo_prepare (fifo_size);
+
+  /*
+   * Try with sorted data
+   */
+  for (i = 0; i < test_data_len; i++)
+    {
+      tp = vp + i;
+      data64 = tp->offset;
+      svm_fifo_enqueue_with_offset (f, tp->offset - f->tail, tp->len,
+				    (u8 *) & data64);
+    }
+
+  /* Expected result: one big fat chunk at offset 4 */
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 1),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+  ooo_seg = svm_fifo_first_ooo_segment (f);
+  TCP_TEST ((ooo_seg->start == 4),
+	    "first ooo seg position %u", ooo_seg->start);
+  TCP_TEST ((ooo_seg->length == 2996),
+	    "first ooo seg length %u", ooo_seg->length);
+
+  data64 = 0;
+  rv = svm_fifo_enqueue_nowait (f, sizeof (u32), (u8 *) & data64);
+  TCP_TEST ((rv == 3000), "bytes to be enqueued %u", rv);
+
+  svm_fifo_free (f);
+  vec_free (vp);
+
+  /*
+   * Now try it again w/ unsorted data...
+   */
+
+  f = fifo_prepare (fifo_size);
+
+  for (i = 0; i < test_data_len; i++)
+    {
+      tp = &test_data[i];
+      data64 = tp->offset;
+      rv = svm_fifo_enqueue_with_offset (f, tp->offset - f->tail, tp->len,
+					 (u8 *) & data64);
+      if (rv)
+	{
+	  clib_warning ("enqueue returned %d", rv);
+	}
+    }
+
+  /* Expecting the same result: one big fat chunk at offset 4 */
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 1),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+  ooo_seg = svm_fifo_first_ooo_segment (f);
+  TCP_TEST ((ooo_seg->start == 4),
+	    "first ooo seg position %u", ooo_seg->start);
+  TCP_TEST ((ooo_seg->length == 2996),
+	    "first ooo seg length %u", ooo_seg->length);
+
+  data64 = 0;
+  rv = svm_fifo_enqueue_nowait (f, sizeof (u32), (u8 *) & data64);
+
+  TCP_TEST ((rv == 3000), "bytes to be enqueued %u", rv);
+
+  svm_fifo_free (f);
+
+  return 0;
+}
+
+static int
+tcp_test_fifo3 (vlib_main_t * vm, unformat_input_t * input)
+{
+  svm_fifo_t *f;
+  u32 fifo_size = 4 << 10;
+  u32 fifo_initial_offset = 0;
+  u32 total_size = 2 << 10;
+  int overlap = 0, verbose = 0, randomize = 1, drop = 0, in_seq_all = 0;
+  u8 *data_pattern = 0, *data_buf = 0;
+  test_pattern_t *tp, *generate = 0;
+  u32 nsegs = 2, seg_size, length_so_far;
+  u32 current_offset, offset_increment, len_this_chunk;
+  u32 seed = 0xdeaddabe, j;
+  int i, rv;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "fifo-size %d", &fifo_size))
+	;
+      else if (unformat (input, "total-size %d", &total_size))
+	;
+      else if (unformat (input, "verbose"))
+	verbose = 1;
+      else if (unformat (input, "overlap"))
+	overlap = 1;
+      else if (unformat (input, "initial-offset %d", &fifo_initial_offset))
+	;
+      else if (unformat (input, "seed %d", &seed))
+	;
+      else if (unformat (input, "nsegs %d", &nsegs))
+	;
+      else if (unformat (input, "no-randomize"))
+	randomize = 0;
+      else if (unformat (input, "in-seq-all"))
+	in_seq_all = 1;
+      else if (unformat (input, "drop"))
+	drop = 1;
+      else
+	{
+	  clib_error_t *e = clib_error_return
+	    (0, "unknown input `%U'", format_unformat_error, input);
+	  clib_error_report (e);
+	  return -1;
+	}
+    }
+
+  if (total_size > fifo_size)
+    {
+      clib_warning ("total_size %d greater than fifo size %d", total_size,
+		    fifo_size);
+      return -1;
+    }
+  if (overlap && randomize == 0)
+    {
+      clib_warning ("Can't enqueue in-order with overlap");
+      return -1;
+    }
+
+  /*
+   * Generate data
+   */
+  vec_validate (data_pattern, total_size - 1);
+  for (i = 0; i < vec_len (data_pattern); i++)
+    data_pattern[i] = i & 0xff;
+
+  /*
+   * Generate segments
+   */
+  seg_size = total_size / nsegs;
+  length_so_far = 0;
+  current_offset = randomize;
+  while (length_so_far < total_size)
+    {
+      vec_add2 (generate, tp, 1);
+      len_this_chunk = clib_min (seg_size, total_size - length_so_far);
+      tp->offset = current_offset;
+      tp->len = len_this_chunk;
+
+      if (overlap && (len_this_chunk == seg_size))
+	do
+	  {
+	    offset_increment = len_this_chunk
+	      % (1 + (random_u32 (&seed) % len_this_chunk));
+	  }
+	while (offset_increment == 0);
+      else
+	offset_increment = len_this_chunk;
+
+      current_offset += offset_increment;
+      length_so_far = tp->offset + tp->len;
+    }
+
+  /*
+   * Validate segment list. Only valid for non-overlap cases.
+   */
+  if (overlap == 0)
+    fifo_validate_pattern (vm, generate, vec_len (generate));
+
+  if (verbose)
+    {
+      vlib_cli_output (vm, "raw data pattern:");
+      for (i = 0; i < vec_len (generate); i++)
+	{
+	  vlib_cli_output (vm, "[%d] offset %u len %u", i,
+			   generate[i].offset, generate[i].len);
+	}
+    }
+
+  /* Randomize data pattern */
+  if (randomize)
+    {
+      for (i = 0; i < vec_len (generate) / 2; i++)
+	{
+	  u32 src_index, dst_index;
+	  test_pattern_t _tmp, *tmp = &_tmp;
+
+	  src_index = random_u32 (&seed) % vec_len (generate);
+	  dst_index = random_u32 (&seed) % vec_len (generate);
+
+	  tmp[0] = generate[dst_index];
+	  generate[dst_index] = generate[src_index];
+	  generate[src_index] = tmp[0];
+	}
+      if (verbose)
+	{
+	  vlib_cli_output (vm, "randomized data pattern:");
+	  for (i = 0; i < vec_len (generate); i++)
+	    {
+	      vlib_cli_output (vm, "[%d] offset %u len %u", i,
+			       generate[i].offset, generate[i].len);
+	    }
+	}
+    }
+
+  /*
+   * Create a fifo and add segments
+   */
+  f = fifo_prepare (fifo_size);
+
+  /* manually set head and tail pointers to validate modular arithmetic */
+  fifo_initial_offset = fifo_initial_offset % fifo_size;
+  f->head = fifo_initial_offset;
+  f->tail = fifo_initial_offset;
+
+  for (i = !randomize; i < vec_len (generate); i++)
+    {
+      tp = generate + i;
+      svm_fifo_enqueue_with_offset (f,
+				    fifo_initial_offset + tp->offset -
+				    f->tail, tp->len,
+				    (u8 *) data_pattern + tp->offset);
+    }
+
+  /* Add the first segment in order for non random data */
+  if (!randomize)
+    svm_fifo_enqueue_nowait (f, generate[0].len, (u8 *) data_pattern);
+
+  /*
+   * Expected result: one big fat chunk at offset 1 if randomize == 1
+   */
+
+  if (verbose)
+    vlib_cli_output (vm, "fifo before missing link: %U",
+		     format_svm_fifo, f, 1 /* verbose */ );
+
+  /*
+   * Add the missing byte if segments were randomized
+   */
+  if (randomize)
+    {
+      u32 bytes_to_enq = 1;
+      if (in_seq_all)
+	bytes_to_enq = total_size;
+      rv = svm_fifo_enqueue_nowait (f, bytes_to_enq, data_pattern + 0);
+
+      if (verbose)
+	vlib_cli_output (vm, "in-order enqueue returned %d", rv);
+
+      TCP_TEST ((rv == total_size), "enqueued %u expected %u", rv,
+		total_size);
+
+    }
+
+  TCP_TEST ((svm_fifo_has_ooo_data (f) == 0), "number of ooo segments %u",
+	    svm_fifo_number_ooo_segments (f));
+
+  /*
+   * Test if peeked data is the same as original data
+   */
+  vec_validate (data_buf, vec_len (data_pattern));
+  svm_fifo_peek (f, 0, vec_len (data_pattern), data_buf);
+  if (compare_data (data_buf, data_pattern, 0, vec_len (data_pattern), &j))
+    {
+      TCP_TEST (0, "[%d] peeked %u expected %u", j, data_buf[j],
+		data_pattern[j]);
+    }
+  vec_reset_length (data_buf);
+
+  /*
+   * Dequeue or drop all data
+   */
+  if (drop)
+    {
+      svm_fifo_dequeue_drop (f, vec_len (data_pattern));
+    }
+  else
+    {
+      svm_fifo_dequeue_nowait (f, vec_len (data_pattern), data_buf);
+      if (compare_data
+	  (data_buf, data_pattern, 0, vec_len (data_pattern), &j))
+	{
+	  TCP_TEST (0, "[%d] dequeued %u expected %u", j, data_buf[j],
+		    data_pattern[j]);
+	}
+    }
+
+  TCP_TEST ((svm_fifo_max_dequeue (f) == 0), "fifo has %d bytes",
+	    svm_fifo_max_dequeue (f));
+
+  svm_fifo_free (f);
+  vec_free (data_pattern);
+  vec_free (data_buf);
+
+  return 0;
+}
+
+static int
+tcp_test_fifo4 (vlib_main_t * vm, unformat_input_t * input)
+{
+  svm_fifo_t *f;
+  u32 fifo_size = 6 << 10;
+  u32 fifo_initial_offset = 1000000000;
+  u32 test_n_bytes = 5000, j;
+  u8 *test_data = 0, *data_buf = 0;
+  int i, rv, verbose = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	verbose = 1;
+      else
+	{
+	  clib_error_t *e = clib_error_return
+	    (0, "unknown input `%U'", format_unformat_error, input);
+	  clib_error_report (e);
+	  return -1;
+	}
+    }
+
+  /*
+   * Create a fifo and add segments
+   */
+  f = fifo_prepare (fifo_size);
+
+  /* Set head and tail pointers */
+  fifo_initial_offset = fifo_initial_offset % fifo_size;
+  svm_fifo_init_pointers (f, fifo_initial_offset);
+
+  vec_validate (test_data, test_n_bytes - 1);
+  for (i = 0; i < vec_len (test_data); i++)
+    test_data[i] = i;
+
+  for (i = test_n_bytes - 1; i > 0; i--)
+    {
+      rv = svm_fifo_enqueue_with_offset (f, fifo_initial_offset + i - f->tail,
+					 sizeof (u8), &test_data[i]);
+      if (verbose)
+	vlib_cli_output (vm, "add [%d] [%d, %d]", i, i, i + sizeof (u8));
+      if (rv)
+	{
+	  clib_warning ("enqueue returned %d", rv);
+	  svm_fifo_free (f);
+	  vec_free (test_data);
+	  return -1;
+	}
+    }
+
+  svm_fifo_enqueue_nowait (f, sizeof (u8), &test_data[0]);
+
+  vec_validate (data_buf, vec_len (test_data));
+
+  svm_fifo_dequeue_nowait (f, vec_len (test_data), data_buf);
+  rv = compare_data (data_buf, test_data, 0, vec_len (test_data), &j);
+  if (rv)
+    vlib_cli_output (vm, "[%d] dequeued %u expected %u", j, data_buf[j],
+		     test_data[j]);
+  TCP_TEST ((rv == 0), "dequeued compared to original returned %d", rv);
+
+  svm_fifo_free (f);
+  vec_free (test_data);
+  return 0;
+}
+
+static u32
+fifo_pos (svm_fifo_t * f, u32 pos)
+{
+  return pos % f->nitems;
+}
+
+static int
+tcp_test_fifo5 (vlib_main_t * vm, unformat_input_t * input)
+{
+  svm_fifo_t *f;
+  u32 fifo_size = 400, j = 0, offset = 200;
+  int i, rv, verbose = 0;
+  u8 *test_data = 0, *data_buf = 0;
+  ooo_segment_t *ooo_seg;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	verbose = 1;
+      else
+	{
+	  clib_error_t *e = clib_error_return
+	    (0, "unknown input `%U'", format_unformat_error, input);
+	  clib_error_report (e);
+	  return -1;
+	}
+    }
+
+  f = fifo_prepare (fifo_size);
+  svm_fifo_init_pointers (f, offset);
+
+  vec_validate (test_data, 399);
+  for (i = 0; i < vec_len (test_data); i++)
+    test_data[i] = i % 0xff;
+
+  /*
+   * Start with [100, 200] and [300, 400]
+   */
+  svm_fifo_enqueue_with_offset (f, 100, 100, &test_data[100]);
+  svm_fifo_enqueue_with_offset (f, 300, 100, &test_data[300]);
+
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 2),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+  TCP_TEST ((f->ooos_newest == 1), "newest %u", f->ooos_newest);
+  if (verbose)
+    vlib_cli_output (vm, "fifo after [100, 200] and [300, 400] : %U",
+		     format_svm_fifo, f, 2 /* verbose */ );
+
+  /*
+   * Add [225, 275]
+   */
+
+  rv = svm_fifo_enqueue_with_offset (f, 225, 50, &test_data[200]);
+  if (verbose)
+    vlib_cli_output (vm, "fifo after [225, 275] : %U",
+		     format_svm_fifo, f, 2 /* verbose */ );
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 3),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+  ooo_seg = svm_fifo_first_ooo_segment (f);
+  TCP_TEST ((ooo_seg->start == fifo_pos (f, 100 + offset)),
+	    "first seg start %u expected %u", ooo_seg->start,
+	    fifo_pos (f, 100 + offset));
+  TCP_TEST ((ooo_seg->length == 100), "first seg length %u expected %u",
+	    ooo_seg->length, 100);
+  ooo_seg = ooo_segment_next (f, ooo_seg);
+  TCP_TEST ((ooo_seg->start == fifo_pos (f, 225 + offset)),
+	    "second seg start %u expected %u",
+	    ooo_seg->start, fifo_pos (f, 225 + offset));
+  TCP_TEST ((ooo_seg->length == 50), "second seg length %u expected %u",
+	    ooo_seg->length, 50);
+  ooo_seg = ooo_segment_next (f, ooo_seg);
+  TCP_TEST ((ooo_seg->start == fifo_pos (f, 300 + offset)),
+	    "third seg start %u expected %u",
+	    ooo_seg->start, fifo_pos (f, 300 + offset));
+  TCP_TEST ((ooo_seg->length == 100), "third seg length %u expected %u",
+	    ooo_seg->length, 100);
+  TCP_TEST ((f->ooos_newest == 2), "newest %u", f->ooos_newest);
+  /*
+   * Add [190, 310]
+   */
+  rv = svm_fifo_enqueue_with_offset (f, 190, 120, &test_data[190]);
+  if (verbose)
+    vlib_cli_output (vm, "fifo after [190, 310] : %U",
+		     format_svm_fifo, f, 1 /* verbose */ );
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 1),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+  ooo_seg = svm_fifo_first_ooo_segment (f);
+  TCP_TEST ((ooo_seg->start == fifo_pos (f, offset + 100)),
+	    "first seg start %u expected %u",
+	    ooo_seg->start, fifo_pos (f, offset + 100));
+  TCP_TEST ((ooo_seg->length == 300), "first seg length %u expected %u",
+	    ooo_seg->length, 300);
+
+  /*
+   * Add [0, 150]
+   */
+  rv = svm_fifo_enqueue_nowait (f, 150, test_data);
+
+  if (verbose)
+    vlib_cli_output (vm, "fifo after [0 150] : %U", format_svm_fifo, f,
+		     2 /* verbose */ );
+
+  TCP_TEST ((rv == 400), "managed to enqueue %u expected %u", rv, 400);
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 0),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+
+  vec_validate (data_buf, 399);
+  svm_fifo_peek (f, 0, 400, data_buf);
+  if (compare_data (data_buf, test_data, 0, 400, &j))
+    {
+      TCP_TEST (0, "[%d] peeked %u expected %u", j, data_buf[j],
+		test_data[j]);
+    }
+
+  /*
+   * Add [100 200] and overlap it with [50 250]
+   */
+  svm_fifo_free (f);
+  f = fifo_prepare (fifo_size);
+
+  svm_fifo_enqueue_with_offset (f, 100, 100, &test_data[100]);
+  svm_fifo_enqueue_with_offset (f, 50, 200, &test_data[50]);
+  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 1),
+	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+  ooo_seg = svm_fifo_first_ooo_segment (f);
+  TCP_TEST ((ooo_seg->start == 50), "first seg start %u expected %u",
+	    ooo_seg->start, 50);
+  TCP_TEST ((ooo_seg->length == 200), "first seg length %u expected %u",
+	    ooo_seg->length, 200);
+
+  svm_fifo_free (f);
+  vec_free (test_data);
+  return 0;
+}
+
+/* *INDENT-OFF* */
+svm_fifo_trace_elem_t fifo_trace[] = {};
+/* *INDENT-ON* */
+
+static int
+tcp_test_fifo_replay (vlib_main_t * vm, unformat_input_t * input)
+{
+  svm_fifo_t f;
+  int verbose = 0;
+  u8 no_read = 0, *str = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "verbose"))
+	verbose = 1;
+      else if (unformat (input, "no-read"))
+	no_read = 1;
+      else
+	{
+	  clib_error_t *e = clib_error_return
+	    (0, "unknown input `%U'", format_unformat_error, input);
+	  clib_error_report (e);
+	  return -1;
+	}
+    }
+
+#if SVMF_FIFO_TRACE
+  f.trace = fifo_trace;
+#endif
+
+  str = svm_fifo_replay (str, &f, no_read, verbose);
+  vlib_cli_output (vm, "%v", str);
+  return 0;
+}
+
+static int
+tcp_test_fifo (vlib_main_t * vm, unformat_input_t * input)
+{
+  int res = 0;
+  char *str;
+
+  /* Run all tests */
+  if (unformat_check_input (input) == UNFORMAT_END_OF_INPUT)
+    {
+      res = tcp_test_fifo1 (vm, input);
+      if (res)
+	return res;
+
+      res = tcp_test_fifo2 (vm);
+      if (res)
+	return res;
+
+      /*
+       * Run a number of fifo3 configs
+       */
+      str = "nsegs 10 overlap seed 123";
+      unformat_init_cstring (input, str);
+      if (tcp_test_fifo3 (vm, input))
+	return -1;
+      unformat_free (input);
+
+      str = "nsegs 10 overlap seed 123 in-seq-all";
+      unformat_init_cstring (input, str);
+      if (tcp_test_fifo3 (vm, input))
+	return -1;
+      unformat_free (input);
+
+      str = "nsegs 10 overlap seed 123 initial-offset 3917";
+      unformat_init_cstring (input, str);
+      if (tcp_test_fifo3 (vm, input))
+	return -1;
+      unformat_free (input);
+
+      str = "nsegs 10 overlap seed 123 initial-offset 3917 drop";
+      unformat_init_cstring (input, str);
+      if (tcp_test_fifo3 (vm, input))
+	return -1;
+      unformat_free (input);
+
+      str = "nsegs 10 seed 123 initial-offset 3917 drop no-randomize";
+      unformat_init_cstring (input, str);
+      if (tcp_test_fifo3 (vm, input))
+	return -1;
+      unformat_free (input);
+
+      res = tcp_test_fifo4 (vm, input);
+      if (res)
+	return res;
+
+      res = tcp_test_fifo5 (vm, input);
+      if (res)
+	return res;
+    }
+  else
+    {
+      if (unformat (input, "fifo3"))
+	{
+	  res = tcp_test_fifo3 (vm, input);
+	}
+      else if (unformat (input, "fifo2"))
+	{
+	  res = tcp_test_fifo2 (vm);
+	}
+      else if (unformat (input, "fifo1"))
+	{
+	  res = tcp_test_fifo1 (vm, input);
+	}
+      else if (unformat (input, "fifo4"))
+	{
+	  res = tcp_test_fifo4 (vm, input);
+	}
+      else if (unformat (input, "fifo5"))
+	{
+	  res = tcp_test_fifo5 (vm, input);
+	}
+      else if (unformat (input, "replay"))
+	{
+	  res = tcp_test_fifo_replay (vm, input);
+	}
+    }
+
+  return res;
+}
+
+static int
+tcp_test_lookup (vlib_main_t * vm, unformat_input_t * input)
+{
+  session_manager_main_t *smm = &session_manager_main;
+  tcp_main_t *tm = &tcp_main;
+  transport_connection_t _tc1, *tc1 = &_tc1, _tc2, *tc2 = &_tc2, *tconn;
+  tcp_connection_t *tc;
+  stream_session_t *s, *s1;
+  u8 cmp = 0, is_filtered = 0;
+
+  /*
+   * Allocate fake session and connection 1
+   */
+  pool_get (smm->sessions[0], s);
+  memset (s, 0, sizeof (*s));
+  s->session_index = s - smm->sessions[0];
+
+  pool_get (tm->connections[0], tc);
+  memset (tc, 0, sizeof (*tc));
+  tc->connection.c_index = tc - tm->connections[0];
+  tc->connection.s_index = s->session_index;
+  s->connection_index = tc->connection.c_index;
+
+  tc->connection.lcl_ip.ip4.as_u32 = clib_host_to_net_u32 (0x06000101);
+  tc->connection.rmt_ip.ip4.as_u32 = clib_host_to_net_u32 (0x06000103);
+  tc->connection.lcl_port = 35051;
+  tc->connection.rmt_port = 53764;
+  tc->connection.proto = TRANSPORT_PROTO_TCP;
+  tc->connection.is_ip4 = 1;
+  clib_memcpy (tc1, &tc->connection, sizeof (*tc1));
+  s1 = s;
+
+  /*
+   * Allocate fake session and connection 2
+   */
+  pool_get (session_manager_main.sessions[0], s);
+  memset (s, 0, sizeof (*s));
+  s->session_index = s - smm->sessions[0];
+
+  pool_get (tm->connections[0], tc);
+  memset (tc, 0, sizeof (*tc));
+  tc->connection.c_index = tc - tm->connections[0];
+  tc->connection.s_index = s->session_index;
+  s->connection_index = tc->connection.c_index;
+
+  tc->connection.lcl_ip.ip4.as_u32 = clib_host_to_net_u32 (0x06000101);
+  tc->connection.rmt_ip.ip4.as_u32 = clib_host_to_net_u32 (0x06000102);
+  tc->connection.lcl_port = 38225;
+  tc->connection.rmt_port = 53764;
+  tc->connection.proto = TRANSPORT_PROTO_TCP;
+  tc->connection.is_ip4 = 1;
+  clib_memcpy (tc2, &tc->connection, sizeof (*tc2));
+
+  /*
+   * Confirm that connection lookup works
+   */
+
+  session_lookup_add_connection (tc1, session_handle (s1));
+  tconn = session_lookup_connection_wt4 (0, &tc1->lcl_ip.ip4,
+					 &tc1->rmt_ip.ip4,
+					 tc1->lcl_port, tc1->rmt_port,
+					 tc1->proto, 0, &is_filtered);
+
+  TCP_TEST ((tconn != 0), "connection exists");
+  cmp = (memcmp (&tconn->rmt_ip, &tc1->rmt_ip, sizeof (tc1->rmt_ip)) == 0);
+  TCP_TEST ((cmp), "rmt ip is identical %d", cmp);
+  TCP_TEST ((tconn->lcl_port == tc1->lcl_port),
+	    "rmt port is identical %d", tconn->lcl_port == tc1->lcl_port);
+
+  /*
+   * Non-existing connection lookup should not work
+   */
+
+  tconn = session_lookup_connection_wt4 (0, &tc2->lcl_ip.ip4,
+					 &tc2->rmt_ip.ip4,
+					 tc2->lcl_port, tc2->rmt_port,
+					 tc2->proto, 0, &is_filtered);
+  TCP_TEST ((tconn == 0), "lookup result should be null");
+
+  /*
+   * Delete and lookup again
+   */
+  session_lookup_del_connection (tc1);
+  tconn = session_lookup_connection_wt4 (0, &tc1->lcl_ip.ip4,
+					 &tc1->rmt_ip.ip4,
+					 tc1->lcl_port, tc1->rmt_port,
+					 tc1->proto, 0, &is_filtered);
+  TCP_TEST ((tconn == 0), "lookup result should be null");
+  tconn = session_lookup_connection_wt4 (0, &tc2->lcl_ip.ip4,
+					 &tc2->rmt_ip.ip4,
+					 tc2->lcl_port, tc2->rmt_port,
+					 tc2->proto, 0, &is_filtered);
+  TCP_TEST ((tconn == 0), "lookup result should be null");
+
+  /*
+   * Re-add and lookup tc2
+   */
+  session_lookup_add_connection (tc1, tc1->s_index);
+  tconn = session_lookup_connection_wt4 (0, &tc2->lcl_ip.ip4,
+					 &tc2->rmt_ip.ip4,
+					 tc2->lcl_port, tc2->rmt_port,
+					 tc2->proto, 0, &is_filtered);
+  TCP_TEST ((tconn == 0), "lookup result should be null");
+
+  return 0;
+}
+
+static int
+tcp_test_session (vlib_main_t * vm, unformat_input_t * input)
+{
+  int rv = 0;
+  tcp_connection_t *tc0;
+  ip4_address_t local, remote;
+  u16 local_port, remote_port;
+  tcp_main_t *tm = vnet_get_tcp_main ();
+  int is_add = 1;
+
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "del"))
+	is_add = 0;
+      else if (unformat (input, "add"))
+	is_add = 1;
+      else
+	break;
+    }
+
+  if (is_add)
+    {
+      local.as_u32 = clib_host_to_net_u32 (0x06000101);
+      remote.as_u32 = clib_host_to_net_u32 (0x06000102);
+      local_port = clib_host_to_net_u16 (1234);
+      remote_port = clib_host_to_net_u16 (11234);
+
+      pool_get (tm->connections[0], tc0);
+      memset (tc0, 0, sizeof (*tc0));
+
+      tc0->state = TCP_STATE_ESTABLISHED;
+      tc0->rcv_las = 1;
+      tc0->c_c_index = tc0 - tm->connections[0];
+      tc0->c_lcl_port = local_port;
+      tc0->c_rmt_port = remote_port;
+      tc0->c_is_ip4 = 1;
+      tc0->c_thread_index = 0;
+      tc0->c_lcl_ip4.as_u32 = local.as_u32;
+      tc0->c_rmt_ip4.as_u32 = remote.as_u32;
+      tc0->rcv_opts.mss = 1450;
+      tcp_connection_init_vars (tc0);
+
+      TCP_EVT_DBG (TCP_EVT_OPEN, tc0);
+
+      if (stream_session_accept (&tc0->connection, 0 /* listener index */ ,
+				 0 /* notify */ ))
+	clib_warning ("stream_session_accept failed");
+
+      stream_session_accept_notify (&tc0->connection);
+    }
+  else
+    {
+      tc0 = tcp_connection_get (0 /* connection index */ , 0 /* thread */ );
+      tc0->state = TCP_STATE_CLOSED;
+      stream_session_disconnect_notify (&tc0->connection);
+    }
+
+  return rv;
+}
+
+static clib_error_t *
+tcp_test (vlib_main_t * vm,
+	  unformat_input_t * input, vlib_cli_command_t * cmd_arg)
+{
+  int res = 0;
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "sack"))
+	{
+	  res = tcp_test_sack (vm, input);
+	}
+      else if (unformat (input, "fifo"))
+	{
+	  res = tcp_test_fifo (vm, input);
+	}
+      else if (unformat (input, "session"))
+	{
+	  res = tcp_test_session (vm, input);
+	}
+      else if (unformat (input, "lookup"))
+	{
+	  res = tcp_test_lookup (vm, input);
+	}
+      else if (unformat (input, "all"))
+	{
+	  if ((res = tcp_test_sack (vm, input)))
+	    goto done;
+	  if ((res = tcp_test_fifo (vm, input)))
+	    goto done;
+	  if ((res = tcp_test_lookup (vm, input)))
+	    goto done;
+	}
+      else
+	break;
+    }
+
+done:
+  if (res)
+    return clib_error_return (0, "TCP unit test failed");
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (tcp_test_command, static) =
+{
+  .path = "test tcp",
+  .short_help = "internal tcp unit tests",
+  .function = tcp_test,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/unittest/unittest.c b/src/plugins/unittest/unittest.c
new file mode 100644
index 00000000000..60ebac130da
--- /dev/null
+++ b/src/plugins/unittest/unittest.c
@@ -0,0 +1,37 @@
+/*
+ * unittest.c - vpp unit-test plugin
+ *
+ * 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/vnet.h>
+#include <vnet/plugin/plugin.h>
+#include <vpp/app/version.h>
+
+/* *INDENT-OFF* */
+VLIB_PLUGIN_REGISTER () =
+{
+  .version = VPP_BUILD_VER,
+  .description = "C unit tests",
+  .default_disabled = 1,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/plugins/unittest/util_test.c b/src/plugins/unittest/util_test.c
new file mode 100644
index 00000000000..d2f2715d763
--- /dev/null
+++ b/src/plugins/unittest/util_test.c
@@ -0,0 +1,54 @@
+/*
+ * 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 <vlib/vlib.h>
+
+static clib_error_t *
+test_crash_command_fn (vlib_main_t * vm,
+		       unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  u64 *p = (u64 *) 0xdefec8ed;
+
+  /* *INDENT-OFF* */
+  ELOG_TYPE_DECLARE (e) =
+    {
+      .format = "deliberate crash: touching %x",
+      .format_args = "i4",
+    };
+  /* *INDENT-ON* */
+  elog (&vm->elog_main, &e, 0xdefec8ed);
+
+  *p = 0xdeadbeef;
+
+  /* Not so much... */
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (test_crash_command, static) =
+{
+  .path = "test crash",
+  .short_help = "crash the bus!",
+  .function = test_crash_command_fn,
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */