src/vnet/tcp/tcp_test.c

/*
 * 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;                                               \
    }								\
}

static int
tcp_test_sack ()
{
  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;

  memset (tc, 0, sizeof (*tc));

  tc->snd_una = 0;
  tc->snd_una_max = 1000;
  tc->snd_nxt = 1000;
  tc->opt.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->opt.sacks, sacks[i * 2]);
    }
  tc->opt.n_sack_blocks = vec_len (tc->opt.sacks);
  tcp_rcv_sacks (tc, 0);

  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);

  /*
   * Inject odd blocks
   */

  vec_reset_length (tc->opt.sacks);
  for (i = 0; i < 1000 / 200; i++)
    {
      vec_add1 (tc->opt.sacks, sacks[i * 2 + 1]);
    }
  tc->opt.n_sack_blocks = vec_len (tc->opt.sacks);
  tcp_rcv_sacks (tc, 0);

  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->max_byte_sacked == 1000),
	    "max sacked byte %u", sb->max_byte_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);

  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->max_byte_sacked == 1000),
	    "max sacked byte %u", sb->max_byte_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->opt.sacks);

  block.start = 1200;
  block.end = 1300;
  vec_add1 (tc->opt.sacks, block);

  tc->snd_una_max = 1500;
  tc->snd_una = 1000;
  tc->snd_nxt = 1500;
  tcp_rcv_sacks (tc, 1000);

  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);
  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->opt.sacks);
  tcp_rcv_sacks (tc, 1200);

  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));

  /*
   * Remove all
   */

  scoreboard_clear (sb);
  TCP_TEST ((pool_elts (sb->holes) == 0),
	    "number of holes %d", pool_elts (sb->holes));
  return 0;
}

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;
}

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;
  ooo_segment_t *ooo_seg;
  u8 *data;

  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 = svm_fifo_create (fifo_size);

  /* Paint fifo data vector with -1's */
  memset (f->data, 0xFF, test_data_len);

  /* Enqueue an initial (un-dequeued) chunk */
  rv = svm_fifo_enqueue_nowait (f, 0 /* pid */ ,
				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);
      data = (u8 *) (test_data + (2 * i + 1));
      rv =
	svm_fifo_enqueue_with_offset (f, 0 /* pid */ , 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);

  /* Paint some of missing data backwards */
  for (i = 3; i > 1; i--)
    {
      offset = (2 * i + 0) * sizeof (u32);
      data = (u8 *) (test_data + (2 * i + 0));
      rv =
	svm_fifo_enqueue_with_offset (f, 0 /* pid */ , 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, 0 /* pid */ , 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, 0 /* pid */ , 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;
	}
    }

  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 = svm_fifo_create (fifo_size);

  /* Paint the fifo data vector with -1's */
  memset (f->data, 0xFF, 1 << 20);

  /*
   * Try with sorted data
   */
  for (i = 0; i < test_data_len; i++)
    {
      tp = vp + i;
      data64 = tp->offset;
      rv = svm_fifo_enqueue_with_offset (f, 0, tp->offset, 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, 0, 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 = svm_fifo_create (fifo_size);

  /* Paint fifo data vector with -1's */
  memset (f->data, 0xFF, 1 << 20);

  for (i = 0; i < test_data_len; i++)
    {
      tp = &test_data[i];
      data64 = tp->offset;
      rv = svm_fifo_enqueue_with_offset (f, 0, tp->offset, 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, 0, 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;
  int i, rv;
  u8 *data_pattern = 0;
  test_pattern_t *tp, *generate = 0;
  u32 nsegs = 2;
  u32 seg_size, length_so_far;
  u32 current_offset, offset_increment, len_this_chunk;
  u32 seed = 0xdeaddabe;
  int verbose = 0;
  int randomize = 1;

  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
	{
	  clib_error_t *e = clib_error_return
	    (0, "unknown input `%U'", format_unformat_error, input);
	  clib_error_report (e);
	  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;

  seg_size = total_size / nsegs;
  length_so_far = 0;
  current_offset = 1;
  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 */
  f = svm_fifo_create (fifo_size);

  /* Paint the fifo data vector with -1's */
  memset (f->data, 0xFF, fifo_size);

  /* manually set head and tail pointers to validate modular arithmetic */
  f->head = fifo_initial_offset % fifo_size;
  f->tail = fifo_initial_offset % fifo_size;

  for (i = 0; i < vec_len (generate); i++)
    {
      tp = generate + i;
      rv = svm_fifo_enqueue_with_offset (f, 0, tp->offset, tp->len,
					 (u8 *) data_pattern + tp->offset);
    }

  /* Expected result: one big fat chunk at offset 1 */

  if (verbose)
    vlib_cli_output (vm, "fifo before missing link: %U",
		     format_svm_fifo, f, 1 /* verbose */ );

  rv = svm_fifo_enqueue_nowait (f, 0, 1 /* count */ , data_pattern + 0);

  if (verbose)
    vlib_cli_output (vm, "in-order enqueue returned %d", rv);

  TCP_TEST ((rv == total_size), "retrieved %u expected %u", rv, total_size);
  TCP_TEST ((svm_fifo_number_ooo_segments (f) == 0),
	    "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
  svm_fifo_free (f);
  vec_free (data_pattern);

  return 0;
}

static int
tcp_test_fifo (vlib_main_t * vm, unformat_input_t * input)
{
  int res = 0;

  /* 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 */
      unformat_init_cstring (input, "nsegs 3 overlap seed 123");
      if (tcp_test_fifo3 (vm, input))
	return -1;
      unformat_free (input);

      unformat_init_cstring (input, "nsegs 10");
      if (tcp_test_fifo3 (vm, input))
	return -1;
      unformat_free (input);
    }
  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);
	}
    }

  return res;
}

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 ();
	}
      else if (unformat (input, "fifo"))
	{
	  res = tcp_test_fifo (vm, input);
	}
      else
	{
	  return clib_error_return (0, "unknown input `%U'",
				    format_unformat_error, input);
	}
    }

  if (res)
    {
      return clib_error_return (0, "TCP unit test failed");
    }
  else
    {
      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:
 */