path: root/filter/trie_test.c

/*
 *	Filters: Utility Functions Tests
 *
 *	(c) 2015 CZ.NIC z.s.p.o.
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

#include "test/birdtest.h"
#include "test/bt-utils.h"

#include "filter/filter.h"
#include "filter/data.h"
#include "conf/conf.h"

#define TESTS_NUM		10
#define PREFIXES_NUM 		32
#define PREFIX_TESTS_NUM 	10000
#define PREFIX_BENCH_NUM 	100000000

#define TRIE_BUFFER_SIZE	1024
#define TEST_BUFFER_SIZE	(1024*1024)
#define BIG_BUFFER_SIZE		10000

/* Wrapping structure for storing f_prefixes structures in list */
struct f_prefix_node {
  node n;
  struct f_prefix prefix;
};

static u32
xrandom(u32 max)
{
  return (bt_random() % max);
}

static inline uint
get_exp_random(void)
{
  uint r, n = 0;

  for (r = bt_random(); r & 1; r = r >> 1)
    n++;

  return n;
}

static int
compare_prefixes(const void *a, const void *b)
{
  return net_compare(&((const struct f_prefix *) a)->net,
		     &((const struct f_prefix *) b)->net);
}

static inline int
matching_ip4_nets(const net_addr_ip4 *a, const net_addr_ip4 *b)
{
  ip4_addr cmask = ip4_mkmask(MIN(a->pxlen, b->pxlen));
  return ip4_compare(ip4_and(a->prefix, cmask), ip4_and(b->prefix, cmask)) == 0;
}

static inline int
matching_ip6_nets(const net_addr_ip6 *a, const net_addr_ip6 *b)
{
  ip6_addr cmask = ip6_mkmask(MIN(a->pxlen, b->pxlen));
  return ip6_compare(ip6_and(a->prefix, cmask), ip6_and(b->prefix, cmask)) == 0;
}

static inline int
matching_nets(const net_addr *a, const net_addr *b)
{
  if (a->type != b->type)
    return 0;

  return (a->type == NET_IP4) ?
    matching_ip4_nets((const net_addr_ip4 *) a, (const net_addr_ip4 *) b) :
    matching_ip6_nets((const net_addr_ip6 *) a, (const net_addr_ip6 *) b);
}

static int
is_prefix_included(list *prefixes, const net_addr *needle)
{
  struct f_prefix_node *n;
  WALK_LIST(n, *prefixes)
    if (matching_nets(&n->prefix.net, needle) &&
	(n->prefix.lo <= needle->pxlen) && (needle->pxlen <= n->prefix.hi))
    {
      char buf[64];
      bt_format_net(buf, 64, &n->prefix.net);
      bt_debug("FOUND %s %d-%d\n", buf, n->prefix.lo, n->prefix.hi);

      return 1; /* OK */
    }

  return 0; /* FAIL */
}

static void
get_random_net(net_addr *net, int v6)
{
  if (!v6)
  {
    uint pxlen = xrandom(24)+8;
    ip4_addr ip4 = ip4_from_u32((u32) bt_random());
    net_fill_ip4(net, ip4_and(ip4, ip4_mkmask(pxlen)), pxlen);
  }
  else
  {
    uint pxlen = xrandom(120)+8;
    ip6_addr ip6 = ip6_build(bt_random(), bt_random(), bt_random(), bt_random());
    net_fill_ip6(net, ip6_and(ip6, ip6_mkmask(pxlen)), pxlen);
  }
}

static void
get_random_prefix(struct f_prefix *px, int v6, int tight)
{
  get_random_net(&px->net, v6);

  if (tight)
  {
    px->lo = px->hi = px->net.pxlen;
  }
  else if (bt_random() % 2)
  {
    px->lo = 0;
    px->hi = px->net.pxlen;
  }
  else
  {
    px->lo = px->net.pxlen;
    px->hi = net_max_prefix_length[px->net.type];
  }
}

static void
get_random_ip4_subnet(net_addr_ip4 *net, const net_addr_ip4 *src, int pxlen)
{
  *net = NET_ADDR_IP4(ip4_and(src->prefix, ip4_mkmask(pxlen)), pxlen);

  if (pxlen > src->pxlen)
  {
    ip4_addr rnd = ip4_from_u32((u32) bt_random());
    ip4_addr mask = ip4_xor(ip4_mkmask(src->pxlen), ip4_mkmask(pxlen));
    net->prefix = ip4_or(net->prefix, ip4_and(rnd, mask));
  }
}

static void
get_random_ip6_subnet(net_addr_ip6 *net, const net_addr_ip6 *src, int pxlen)
{
  *net = NET_ADDR_IP6(ip6_and(src->prefix, ip6_mkmask(pxlen)), pxlen);

  if (pxlen > src->pxlen)
  {
    ip6_addr rnd = ip6_build(bt_random(), bt_random(), bt_random(), bt_random());
    ip6_addr mask = ip6_xor(ip6_mkmask(src->pxlen), ip6_mkmask(pxlen));
    net->prefix = ip6_or(net->prefix, ip6_and(rnd, mask));
  }
}

static void
get_random_subnet(net_addr *net, const net_addr *src, int pxlen)
{
  if (src->type == NET_IP4)
    get_random_ip4_subnet((net_addr_ip4 *) net, (const net_addr_ip4 *) src, pxlen);
  else
    get_random_ip6_subnet((net_addr_ip6 *) net, (const net_addr_ip6 *) src, pxlen);
}

static void
get_inner_net(net_addr *net, const struct f_prefix *src)
{
  int pxlen, step;

  if (bt_random() % 2)
  {
    step = get_exp_random();
    step = MIN(step, src->hi - src->lo);
    pxlen = (bt_random() % 2) ? (src->lo + step) : (src->hi - step);
  }
  else
    pxlen = src->lo + bt_random() % (src->hi - src->lo + 1);

  get_random_subnet(net, &src->net, pxlen);
}

static void
swap_random_bits_ip4(net_addr_ip4 *net, int num)
{
  for (int i = 0; i < num; i++)
  {
    ip4_addr swap = IP4_NONE;
    ip4_setbit(&swap, bt_random() % net->pxlen);
    net->prefix = ip4_xor(net->prefix, swap);
  }
}

static void
swap_random_bits_ip6(net_addr_ip6 *net, int num)
{
  for (int i = 0; i < num; i++)
  {
    ip6_addr swap = IP6_NONE;
    ip6_setbit(&swap, bt_random() % net->pxlen);
    net->prefix = ip6_xor(net->prefix, swap);
  }
}

static void
swap_random_bits(net_addr *net, int num)
{
  if (net->type == NET_IP4)
    swap_random_bits_ip4((net_addr_ip4 *) net, num);
  else
    swap_random_bits_ip6((net_addr_ip6 *) net, num);
}

static void
get_outer_net(net_addr *net, const struct f_prefix *src)
{
  int pxlen, step;
  int inside = 0;
  int max = net_max_prefix_length[src->net.type];

  if ((src->lo > 0) && (bt_random() % 3))
  {
    step = 1 + get_exp_random();
    step = MIN(step, src->lo);
    pxlen = src->lo - step;
  }
  else if ((src->hi < max) && (bt_random() % 2))
  {
    step = 1 + get_exp_random();
    step = MIN(step, max - src->hi);
    pxlen = src->hi + step;
  }
  else
  {
    pxlen = src->lo + bt_random() % (src->hi - src->lo + 1);
    inside = 1;
  }

  get_random_subnet(net, &src->net, pxlen);

  /* Perhaps swap some bits in prefix */
  if ((net->pxlen > 0) && (inside || (bt_random() % 4)))
    swap_random_bits(net, 1 + get_exp_random());
}

static list *
make_random_prefix_list(int num, int v6, int tight)
{
  list *prefixes = tmp_allocz(sizeof(struct f_prefix_node));
  init_list(prefixes);

  for (int i = 0; i < num; i++)
  {
    struct f_prefix_node *px = tmp_allocz(sizeof(struct f_prefix_node));
    get_random_prefix(&px->prefix, v6, tight);
    add_tail(prefixes, &px->n);

    char buf[64];
    bt_format_net(buf, 64, &px->prefix.net);
    bt_debug("ADD %s{%d,%d}\n", buf, px->prefix.lo, px->prefix.hi);
  }

  return prefixes;
}

static struct f_trie *
make_trie_from_prefix_list(list *prefixes)
{
  struct f_trie *trie = f_new_trie(tmp_linpool, 0);

  struct f_prefix_node *n;
  WALK_LIST(n, *prefixes)
    trie_add_prefix(trie, &n->prefix.net, n->prefix.lo, n->prefix.hi);

  return trie;
}

/*
 * Read sequence of prefixes from file handle and return prefix list.
 * Each prefix is on one line, sequence terminated by empty line or eof.
 * Arg @plus means prefix should include all longer ones.
 */
static list *
read_prefix_list(FILE *f, int v6, int plus)
{
  ASSERT(!v6);

  uint a0, a1, a2, a3, pl;
  char s[32];
  int n;

  list *pxlist = tmp_allocz(sizeof(struct f_prefix_node));
  init_list(pxlist);

  errno = 0;
  while (fgets(s, 32, f))
  {
    if (s[0] == '\n')
      return pxlist;

    n = sscanf(s, "%u.%u.%u.%u/%u", &a0, &a1, &a2, &a3, &pl);

    if (n != 5)
      bt_abort_msg("Invalid content of trie_data");

    struct f_prefix_node *px = tmp_allocz(sizeof(struct f_prefix_node));
    net_fill_ip4(&px->prefix.net, ip4_build(a0, a1, a2, a3), pl);
    px->prefix.lo = pl;
    px->prefix.hi = plus ? IP4_MAX_PREFIX_LENGTH : pl;
    add_tail(pxlist, &px->n);

    char buf[64];
    bt_format_net(buf, 64, &px->prefix.net);
    bt_debug("ADD %s{%d,%d}\n", buf, px->prefix.lo, px->prefix.hi);
  }

  bt_syscall(errno, "fgets()");
  return EMPTY_LIST(*pxlist) ? NULL : pxlist;
}

/*
 * Open file, read multiple sequences of prefixes from it. Fill @data with
 * prefix lists and @trie with generated tries. Return number of sequences /
 * tries. Use separate linpool @lp0 for prefix lists and @lp1 for tries.
 * Arg @plus means prefix should include all longer ones.
 */
static int
read_prefix_file(const char *filename, int plus,
		 list *data[], struct f_trie *trie[])
{
  FILE *f = fopen(filename, "r");
  bt_syscall(!f, "fopen(%s)", filename);

  int n = 0;
  list *pxlist;
  while (pxlist = read_prefix_list(f, 0, plus))
  {
    data[n] = pxlist;
    trie[n] = make_trie_from_prefix_list(pxlist);
    bt_debug("NEXT\n");
    n++;
  }

  fclose(f);
  bt_debug("DONE reading %d tries\n", n);

  return n;
}

/*
 * Select random subset of @dn prefixes from prefix list @src of length @sn,
 * and store them to buffer @dst (of size @dn). Prefixes may be chosen multiple
 * times. Randomize order of prefixes in @dst buffer.
 */
static void
select_random_prefix_subset(list *src[], net_addr dst[], int sn, int dn)
{
  int pn = 0;

  if (!dn)
    return;

  /* Compute total prefix number */
  for (int i = 0; i < sn; i++)
    pn += list_length(src[i]);

  /* Change of selecting a prefix */
  int rnd = (pn / dn) + 10;
  int n = 0;

  /* Iterate indefinitely over src array */
  for (int i = 0; 1; i++, i = (i < sn) ? i : 0)
  {
    struct f_prefix_node *px;
    WALK_LIST(px, *src[i])
    {
      if (xrandom(rnd) != 0)
	continue;

      net_copy(&dst[n], &px->prefix.net);
      n++;

      /* We have enough */
      if (n == dn)
	goto done;
    }
  }

done:
  /* Shuffle networks */
  for (int i = 0; i < dn; i++)
  {
    int j = xrandom(dn);

    if (i == j)
      continue;

    net_addr tmp;
    net_copy(&tmp, &dst[i]);
    net_copy(&dst[i], &dst[j]);
    net_copy(&dst[j], &tmp);
  }
}

/* Fill @dst buffer with @dn randomly generated /32 prefixes */
static void
make_random_addresses(net_addr dst[], int dn)
{
  for (int i = 0; i < dn; i++)
    net_fill_ip4(&dst[i], ip4_from_u32((u32) bt_random()), IP4_MAX_PREFIX_LENGTH);
}

static void
test_match_net(list *prefixes, struct f_trie *trie, const net_addr *net)
{
  char buf[64];
  bt_format_net(buf, 64, net);
  bt_debug("TEST %s\n", buf);

  int should_be = is_prefix_included(prefixes, net);
  int is_there  = trie_match_net(trie, net);

  bt_assert_msg(should_be == is_there, "Prefix %s %s match", buf,
		(should_be ? "should" : "should not"));
}

static int
t_match_random_net(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  int v6 = 0;
  for (int round = 0; round < TESTS_NUM; round++)
  {
    list *prefixes = make_random_prefix_list(PREFIXES_NUM, v6, 0);
    struct f_trie *trie = make_trie_from_prefix_list(prefixes);

    for (int i = 0; i < PREFIX_TESTS_NUM; i++)
    {
      net_addr net;
      get_random_net(&net, v6);
      test_match_net(prefixes, trie, &net);
    }

    v6 = !v6;
    tmp_flush();
  }

  bt_bird_cleanup();
  return 1;
}

static int
t_match_inner_net(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  int v6 = 0;
  for (int round = 0; round < TESTS_NUM; round++)
  {
    list *prefixes = make_random_prefix_list(PREFIXES_NUM, v6, 0);
    struct f_trie *trie = make_trie_from_prefix_list(prefixes);

    struct f_prefix_node *n = HEAD(*prefixes);
    for (int i = 0; i < PREFIX_TESTS_NUM; i++)
    {
      net_addr net;
      get_inner_net(&net, &n->prefix);
      test_match_net(prefixes, trie, &net);

      n = NODE_VALID(NODE_NEXT(n)) ? NODE_NEXT(n) : HEAD(*prefixes);
    }

    v6 = !v6;
    tmp_flush();
  }

  bt_bird_cleanup();
  return 1;
}

static int
t_match_outer_net(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  int v6 = 0;
  for (int round = 0; round < TESTS_NUM; round++)
  {
    list *prefixes = make_random_prefix_list(PREFIXES_NUM, v6, 0);
    struct f_trie *trie = make_trie_from_prefix_list(prefixes);

    struct f_prefix_node *n = HEAD(*prefixes);
    for (int i = 0; i < PREFIX_TESTS_NUM; i++)
    {
      net_addr net;
      get_outer_net(&net, &n->prefix);
      test_match_net(prefixes, trie, &net);

      n = NODE_VALID(NODE_NEXT(n)) ? NODE_NEXT(n) : HEAD(*prefixes);
    }

    v6 = !v6;
    tmp_flush();
  }

  v6 = !v6;
  bt_bird_cleanup();
  return 1;
}

/*
 * Read prefixes from @filename, build set of tries, prepare test data and do
 * PREFIX_BENCH_NUM trie lookups. With @plus = 0, use random subset of known
 * prefixes as test data, with @plus = 1, use randomly generated /32 prefixes
 * as test data.
 */
static int
benchmark_trie_dataset(const char *filename, int plus)
{
  int n = 0;
  list *data[TRIE_BUFFER_SIZE];
  struct f_trie *trie[TRIE_BUFFER_SIZE];
  net_addr *nets;

  bt_reset_suite_case_timer();
  bt_log_suite_case_result(1, "Reading %s", filename, n);
  n = read_prefix_file(filename, plus, data, trie);
  bt_log_suite_case_result(1, "Read prefix data, %d lists, ", n);

  size_t trie_size = rmemsize(tmp_linpool).effective * 1000 / (1024*1024);
  bt_log_suite_case_result(1, "Trie size %u.%03u MB",
			   (uint) (trie_size / 1000), (uint) (trie_size % 1000));

  int t = PREFIX_BENCH_NUM / n;
  int tb = MIN(t, TEST_BUFFER_SIZE);
  nets = tmp_alloc(tb * sizeof(net_addr));

  if (!plus)
    select_random_prefix_subset(data, nets, n, tb);
  else
    make_random_addresses(nets, tb);

  bt_log_suite_case_result(1, "Make test data, %d (%d) tests", t, tb);
  bt_reset_suite_case_timer();

  /*
  int match = 0;
  for (int i = 0; i < t; i++)
    for (int j = 0; j < n; j++)
      test_match_net(data[j], trie[j], &nets[i]);
  */

  int match = 0;
  for (int i = 0; i < t; i++)
    for (int j = 0; j < n; j++)
      if (trie_match_net(trie[j], &nets[i % TEST_BUFFER_SIZE]))
	match++;

  bt_log_suite_case_result(1, "Matching done, %d / %d matches", match, t * n);

  tmp_flush();
  return 1;
}

static int UNUSED
t_bench_trie_datasets_subset(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  /* Specific datasets, not included */
  benchmark_trie_dataset("trie-data-bgp-1", 0);
  benchmark_trie_dataset("trie-data-bgp-10", 0);
  benchmark_trie_dataset("trie-data-bgp-100", 0);
  benchmark_trie_dataset("trie-data-bgp-1000", 0);

  bt_bird_cleanup();

  return 1;
}

static int UNUSED
t_bench_trie_datasets_random(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  /* Specific datasets, not included */
  benchmark_trie_dataset("trie-data-bgp-1", 1);
  benchmark_trie_dataset("trie-data-bgp-10", 1);
  benchmark_trie_dataset("trie-data-bgp-100", 1);
  benchmark_trie_dataset("trie-data-bgp-1000", 1);

  bt_bird_cleanup();

  return 1;
}


static int
t_trie_same(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  int v6 = 0;
  for (int round = 0; round < TESTS_NUM*4; round++)
  {
    list *prefixes = make_random_prefix_list(100 * PREFIXES_NUM, v6, 0);
    struct f_trie *trie1 = f_new_trie(tmp_linpool, 0);
    struct f_trie *trie2 = f_new_trie(tmp_linpool, 0);

    struct f_prefix_node *n;
    WALK_LIST(n, *prefixes)
      trie_add_prefix(trie1, &n->prefix.net, n->prefix.lo, n->prefix.hi);

    WALK_LIST_BACKWARDS(n, *prefixes)
      trie_add_prefix(trie2, &n->prefix.net, n->prefix.lo, n->prefix.hi);

    bt_assert(trie_same(trie1, trie2));

    v6 = !v6;
    tmp_flush();
  }

  bt_bird_cleanup();
  return 1;
}

static inline void
log_networks(const net_addr *a, const net_addr *b)
{
  if (bt_verbose >= BT_VERBOSE_ABSOLUTELY_ALL)
  {
    char buf0[64];
    char buf1[64];
    bt_format_net(buf0, 64, a);
    bt_format_net(buf1, 64, b);
    bt_debug("Found %s expected %s\n", buf0, buf1);
  }
}

static int
t_trie_walk(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  for (int round = 0; round < TESTS_NUM*8; round++)
  {
    int level = round / TESTS_NUM;
    int v6 = level % 2;
    int num = PREFIXES_NUM * (int[]){1, 10, 100, 1000}[level / 2];
    int pos = 0, end = 0;
    list *prefixes = make_random_prefix_list(num, v6, 1);
    struct f_trie *trie = make_trie_from_prefix_list(prefixes);
    struct f_prefix *pxset = malloc((num + 1) * sizeof(struct f_prefix));

    struct f_prefix_node *n;
    WALK_LIST(n, *prefixes)
      pxset[pos++] = n->prefix;
    memset(&pxset[pos], 0, sizeof (struct f_prefix));

    qsort(pxset, num, sizeof(struct f_prefix), compare_prefixes);


    /* Full walk */
    bt_debug("Full walk (round %d, %d nets)\n", round, num);

    pos = 0;
    uint pxc = 0;
    TRIE_WALK(trie, net, NULL)
    {
      log_networks(&net, &pxset[pos].net);
      bt_assert(net_equal(&net, &pxset[pos].net));

      /* Skip possible duplicates */
      while (net_equal(&pxset[pos].net, &pxset[pos + 1].net))
	pos++;

      pos++;
      pxc++;
    }
    TRIE_WALK_END;

    bt_assert(pos == num);
    bt_assert(pxc == trie->prefix_count);
    bt_debug("Full walk done\n");


    /* Prepare net for subnet walk - start with random prefix */
    pos = bt_random() % num;
    end = pos + (int[]){2, 2, 3, 4}[level / 2];
    end = MIN(end, num);

    struct f_prefix from = pxset[pos];

    /* Find a common superprefix to several subsequent prefixes */
    for (; pos < end; pos++)
    {
      if (net_equal(&from.net, &pxset[pos].net))
	continue;

      int common = !v6 ?
	ip4_pxlen(net4_prefix(&from.net), net4_prefix(&pxset[pos].net)) :
	ip6_pxlen(net6_prefix(&from.net), net6_prefix(&pxset[pos].net));
      from.net.pxlen = MIN(from.net.pxlen, common);

      if (!v6)
	((net_addr_ip4 *) &from.net)->prefix =
	  ip4_and(net4_prefix(&from.net), net4_prefix(&pxset[pos].net));
      else
	((net_addr_ip6 *) &from.net)->prefix =
	  ip6_and(net6_prefix(&from.net), net6_prefix(&pxset[pos].net));
    }

    /* Fix irrelevant bits */
    if (!v6)
      ((net_addr_ip4 *) &from.net)->prefix =
	ip4_and(net4_prefix(&from.net), ip4_mkmask(net4_pxlen(&from.net)));
    else
      ((net_addr_ip6 *) &from.net)->prefix =
	ip6_and(net6_prefix(&from.net), ip6_mkmask(net6_pxlen(&from.net)));


    /* Find initial position for final prefix */
    for (pos = 0; pos < num; pos++)
      if (compare_prefixes(&pxset[pos], &from) >= 0)
	break;

    int p0 = pos;
    char buf0[64];
    bt_format_net(buf0, 64, &from.net);
    bt_debug("Subnet walk for %s (round %d, %d nets)\n", buf0, round, num);

    /* Subnet walk */
    TRIE_WALK(trie, net, &from.net)
    {
      log_networks(&net, &pxset[pos].net);
      bt_assert(net_equal(&net, &pxset[pos].net));
      bt_assert(net_in_netX(&net, &from.net));

      /* Skip possible duplicates */
      while (net_equal(&pxset[pos].net, &pxset[pos + 1].net))
	pos++;

      pos++;
    }
    TRIE_WALK_END;

    bt_assert((pos == num) || !net_in_netX(&pxset[pos].net, &from.net));
    bt_debug("Subnet walk done for %s (found %d nets)\n", buf0, pos - p0);

    tmp_flush();
  }

  bt_bird_cleanup();
  return 1;
}

static int
find_covering_nets(struct f_prefix *prefixes, int num, const net_addr *net, net_addr *found)
{
  struct f_prefix key;
  net_addr *n = &key.net;
  int found_num = 0;

  net_copy(n, net);

  while (1)
  {
    struct f_prefix *px =
      bsearch(&key, prefixes, num, sizeof(struct f_prefix), compare_prefixes);

    if (px)
    {
      net_copy(&found[found_num], n);
      found_num++;
    }

    if (n->pxlen == 0)
      return found_num;

    n->pxlen--;

    if (n->type == NET_IP4)
      ip4_clrbit(&((net_addr_ip4 *) n)->prefix, n->pxlen);
    else
      ip6_clrbit(&((net_addr_ip6 *) n)->prefix, n->pxlen);
  }
}

static int
t_trie_walk_to_root(void)
{
  bt_bird_init();
  bt_config_parse(BT_CONFIG_SIMPLE);

  for (int round = 0; round < TESTS_NUM * 4; round++)
  {
    int level = round / TESTS_NUM;
    int v6 = level % 2;
    int num = PREFIXES_NUM  * (int[]){32, 512}[level / 2];
    int pos = 0;
    int st = 0, sn = 0, sm = 0;

    list *prefixes = make_random_prefix_list(num, v6, 1);
    struct f_trie *trie = make_trie_from_prefix_list(prefixes);
    struct f_prefix *pxset = malloc((num + 1) * sizeof(struct f_prefix));

    struct f_prefix_node *pxn;
    WALK_LIST(pxn, *prefixes)
      pxset[pos++] = pxn->prefix;
    memset(&pxset[pos], 0, sizeof (struct f_prefix));

    qsort(pxset, num, sizeof(struct f_prefix), compare_prefixes);

    int i;
    for (i = 0; i < (PREFIX_TESTS_NUM / 10); i++)
    {
      net_addr from;
      get_random_net(&from, v6);

      net_addr found[129];
      int found_num = find_covering_nets(pxset, num, &from, found);
      int n = 0;

      if (bt_verbose >= BT_VERBOSE_ABSOLUTELY_ALL)
      {
	char buf[64];
	bt_format_net(buf, 64, &from);
	bt_debug("Lookup for %s (expect %d)\n", buf, found_num);
      }

      /* Walk to root, separate for IPv4 and IPv6 */
      if (!v6)
      {
	TRIE_WALK_TO_ROOT_IP4(trie, (net_addr_ip4 *) &from, net)
	{
	  log_networks((net_addr *) &net, &found[n]);
	  bt_assert((n < found_num) && net_equal((net_addr *) &net, &found[n]));
	  n++;
	}
	TRIE_WALK_TO_ROOT_END;
      }
      else
      {
	TRIE_WALK_TO_ROOT_IP6(trie, (net_addr_ip6 *) &from, net)
	{
	  log_networks((net_addr *) &net, &found[n]);
	  bt_assert((n < found_num) && net_equal((net_addr *) &net, &found[n]));
	  n++;
	}
	TRIE_WALK_TO_ROOT_END;
      }

      bt_assert(n == found_num);

      /* Stats */
      st += n;
      sn += !!n;
      sm = MAX(sm, n);
    }

    bt_debug("Success in %d / %d, sum %d, max %d\n", sn, i, st, sm);

    tmp_flush();
  }

  bt_bird_cleanup();
  return 1;
}

int
main(int argc, char *argv[])
{
  bt_init(argc, argv);

  bt_test_suite(t_match_random_net, "Testing random prefix matching");
  bt_test_suite(t_match_inner_net, "Testing random inner prefix matching");
  bt_test_suite(t_match_outer_net, "Testing random outer prefix matching");
  bt_test_suite(t_trie_same, "A trie filled forward should be same with a trie filled backward.");
  bt_test_suite(t_trie_walk, "Testing TRIE_WALK() on random tries");
  bt_test_suite(t_trie_walk_to_root, "Testing TRIE_WALK_TO_ROOT() on random tries");

  // bt_test_suite(t_bench_trie_datasets_subset, "Benchmark tries from datasets by random subset of nets");
  // bt_test_suite(t_bench_trie_datasets_random, "Benchmark tries from datasets by generated addresses");

  return bt_exit_value();
}