Commit 78ddfd26 authored by Ondrej Zajicek (work)'s avatar Ondrej Zajicek (work)
Browse files

Trie: Clarify handling of less-common net types 

For convenience, Trie functions generally accept as input values not only
NET_IPx types of nets, but also NET_VPNx and NET_ROAx types. But returned
values are always NET_IPx types.
parent 14fc24f3

filter/trie.c

+41 −21
Original line number Diff line number Diff line
@@ -373,9 +373,23 @@ trie_add_prefix(struct f_trie *t, const net_addr *net, uint l, uint h) 


  switch (net->type)

  {

  case NET_IP4: px = ipt_from_ip4(net4_prefix(net)); v4 = 1; break;

  case NET_IP6: px = ipa_from_ip6(net6_prefix(net)); v4 = 0; break;

  default: bug("invalid type");

  case NET_IP4:

  case NET_VPN4:

  case NET_ROA4:

    px = ipt_from_ip4(net4_prefix(net));

    v4 = 1;

    break;



  case NET_IP6:

  case NET_VPN6:

  case NET_ROA6:

  case NET_IP6_SADR:

    px = ipa_from_ip6(net6_prefix(net));

    v4 = 0;

    break;



  default:

    bug("invalid type");

  }



  if (t->ipv4 != v4)
@@ -562,7 +576,9 @@ trie_match_net(const struct f_trie *t, const net_addr *n) 
 * can be used to enumerate all matching prefixes for the network @net using

 * function trie_match_next_longest_ip4() or macro TRIE_WALK_TO_ROOT_IP4().

 *

 * This function assumes IPv4 trie, there is also an IPv6 variant.

 * This function assumes IPv4 trie, there is also an IPv6 variant. The @net

 * argument is typed as net_addr_ip4, but would accept any IPv4-based net_addr,

 * like net4_prefix(). Anyway, returned @dst is always net_addr_ip4.

 *

 * Result: 1 if a matching prefix was found, 0 if not.

 */
@@ -571,6 +587,9 @@ trie_match_longest_ip4(const struct f_trie *t, const net_addr_ip4 *net, net_addr 
{

  ASSERT(t->ipv4);



  const ip4_addr prefix = net->prefix;

  const int pxlen = net->pxlen;



  const struct f_trie_node4 *n = &t->root.v4;

  int len = 0;
@@ -580,13 +599,13 @@ trie_match_longest_ip4(const struct f_trie *t, const net_addr_ip4 *net, net_addr 
  while (n)

  {

    /* We are out of path */

    if (!ip4_prefix_equal(net->prefix, n->addr, MIN(net->pxlen, n->plen)))

    if (!ip4_prefix_equal(prefix, n->addr, MIN(pxlen, n->plen)))

      goto done;



    /* Check accept mask */

    for (; len < n->plen; len++)

    {

      if (len > net->pxlen)

      if (len > pxlen)

	goto done;



      if (ip4_getbit(n->accept, len - 1))
@@ -607,9 +626,9 @@ trie_match_longest_ip4(const struct f_trie *t, const net_addr_ip4 *net, net_addr 
    }



    /* Check local mask */

    for (int pos = 1; pos < (1 << TRIE_STEP); pos = 2 * pos + ip4_getbit(net->prefix, len), len++)

    for (int pos = 1; pos < (1 << TRIE_STEP); pos = 2 * pos + ip4_getbit(prefix, len), len++)

    {

      if (len > net->pxlen)

      if (len > pxlen)

	goto done;



      if (n->local & (1u << pos))
@@ -621,16 +640,14 @@ trie_match_longest_ip4(const struct f_trie *t, const net_addr_ip4 *net, net_addr 
    }



    /* Choose child */

    n = n->c[ip4_getbits(net->prefix, n->plen, TRIE_STEP)];

    n = n->c[ip4_getbits(prefix, n->plen, TRIE_STEP)];

  }



done:

  if (last < 0)

    return 0;



  net_copy_ip4(dst, net);

  dst->prefix = ip4_and(dst->prefix, ip4_mkmask(last));

  dst->pxlen = last;

  *dst = NET_ADDR_IP4(ip4_and(prefix, ip4_mkmask(last)), last);



  if (found0)

    *found0 = found;
@@ -653,7 +670,9 @@ done: 
 * can be used to enumerate all matching prefixes for the network @net using

 * function trie_match_next_longest_ip6() or macro TRIE_WALK_TO_ROOT_IP6().

 *

 * This function assumes IPv6 trie, there is also an IPv4 variant.

 * This function assumes IPv6 trie, there is also an IPv4 variant. The @net

 * argument is typed as net_addr_ip6, but would accept any IPv6-based net_addr,

 * like net6_prefix(). Anyway, returned @dst is always net_addr_ip6.

 *

 * Result: 1 if a matching prefix was found, 0 if not.

 */
@@ -662,6 +681,9 @@ trie_match_longest_ip6(const struct f_trie *t, const net_addr_ip6 *net, net_addr 
{

  ASSERT(!t->ipv4);



  const ip6_addr prefix = net->prefix;

  const int pxlen = net->pxlen;



  const struct f_trie_node6 *n = &t->root.v6;

  int len = 0;
@@ -671,13 +693,13 @@ trie_match_longest_ip6(const struct f_trie *t, const net_addr_ip6 *net, net_addr 
  while (n)

  {

    /* We are out of path */

    if (!ip6_prefix_equal(net->prefix, n->addr, MIN(net->pxlen, n->plen)))

    if (!ip6_prefix_equal(prefix, n->addr, MIN(pxlen, n->plen)))

      goto done;



    /* Check accept mask */

    for (; len < n->plen; len++)

    {

      if (len > net->pxlen)

      if (len > pxlen)

	goto done;



      if (ip6_getbit(n->accept, len - 1))
@@ -698,9 +720,9 @@ trie_match_longest_ip6(const struct f_trie *t, const net_addr_ip6 *net, net_addr 
    }



    /* Check local mask */

    for (int pos = 1; pos < (1 << TRIE_STEP); pos = 2 * pos + ip6_getbit(net->prefix, len), len++)

    for (int pos = 1; pos < (1 << TRIE_STEP); pos = 2 * pos + ip6_getbit(prefix, len), len++)

    {

      if (len > net->pxlen)

      if (len > pxlen)

	goto done;



      if (n->local & (1u << pos))
@@ -712,16 +734,14 @@ trie_match_longest_ip6(const struct f_trie *t, const net_addr_ip6 *net, net_addr 
    }



    /* Choose child */

    n = n->c[ip6_getbits(net->prefix, n->plen, TRIE_STEP)];

    n = n->c[ip6_getbits(prefix, n->plen, TRIE_STEP)];

  }



done:

  if (last < 0)

    return 0;



  net_copy_ip6(dst, net);

  dst->prefix = ip6_and(dst->prefix, ip6_mkmask(last));

  dst->pxlen = last;

  *dst = NET_ADDR_IP6(ip6_and(prefix, ip6_mkmask(last)), last);



  if (found0)

    *found0 = found;

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