void
ipset_bdd_iterator_advance(struct ipset_bdd_iterator *iterator)
{
/* If we're already at the end of the iterator, don't do anything. */
if (CORK_UNLIKELY(iterator->finished)) {
return;
}
/* We look at the last node in the stack. If it's currently
* assigned a false value, then we track down its true branch. If
* it's got a true branch, then we pop it off and check the next to
* last node. */
DEBUG("Advancing BDD iterator");
while (cork_array_size(&iterator->stack) > 0) {
ipset_node_id last_node_id =
cork_array_at
(&iterator->stack, cork_array_size(&iterator->stack) - 1);
struct ipset_node *last_node =
ipset_node_cache_get_nonterminal(iterator->cache, last_node_id);
enum ipset_tribool current_value =
ipset_assignment_get(iterator->assignment, last_node->variable);
/* The current value can't be EITHER, because we definitely
* assign a TRUE or FALSE to the variables of the nodes that we
* encounter. */
if (current_value == IPSET_TRUE) {
/* We've checked both outgoing edges for this node, so pop
* it off and look at its parent. */
iterator->stack.size--;
/* Before continuing, reset this node's variable to
* indeterminate in the assignment. */
ipset_assignment_set
(iterator->assignment, last_node->variable, IPSET_EITHER);
} else {
/* We've checked this node's low edge, but not its high
* edge. Set the variable to TRUE in the assignment, and
* add the high edge's node to the node stack. */
ipset_assignment_set
(iterator->assignment, last_node->variable, IPSET_TRUE);
add_node(iterator, last_node->high);
return;
}
}
/* If we fall through then we ran out of nodes to check. That means
* the iterator is done! */
iterator->finished = true;
}
/**
* Advance the BDD iterator, taking into account that some assignments
* need to be expanded twice.
*/
static void
advance_assignment(struct ipset_iterator *iterator)
{
/* Check the current state of the iterator to determine how to
* advance. */
/* In most cases, the assignment we just finished only needed to be
* expanded once. So we move on to the next assignment and process
* it. */
if (CORK_LIKELY(iterator->multiple_expansion_state ==
IPSET_ITERATOR_NORMAL))
{
ipset_bdd_iterator_advance(iterator->bdd_iterator);
process_assignment(iterator);
return;
}
/* If the assignment needs to be expanded twice, we'll do the IPv4
* expansion first. If that's what we've just finished, do the IPv6
* expansion next. */
if (iterator->multiple_expansion_state == IPSET_ITERATOR_MULTIPLE_IPV4) {
DEBUG("Expanding IPv6 second");
iterator->multiple_expansion_state = IPSET_ITERATOR_MULTIPLE_IPV6;
ipset_assignment_set
(iterator->bdd_iterator->assignment, 0, IPSET_FALSE);
expand_ipv6(iterator);
return;
}
/* If we've just finished the IPv6 expansion, then we've finished
* with this assignment. Before moving on to the next one, we have
* to reset variable 0 to EITHER (which it was before we started
* this whole mess). */
if (iterator->multiple_expansion_state == IPSET_ITERATOR_MULTIPLE_IPV6) {
DEBUG("Finished both expansions");
ipset_assignment_set
(iterator->bdd_iterator->assignment, 0, IPSET_EITHER);
ipset_bdd_iterator_advance(iterator->bdd_iterator);
process_assignment(iterator);
return;
}
}
END_TEST
START_TEST(test_bdd_assignment_cut_1)
{
ipset_assignment_t *a1;
ipset_assignment_t *a2;
a1 = ipset_assignment_new();
ipset_assignment_set(a1, 0, IPSET_TRUE);
ipset_assignment_set(a1, 1, IPSET_FALSE);
a2 = ipset_assignment_new();
ipset_assignment_set(a2, 0, IPSET_TRUE);
ipset_assignment_set(a2, 1, IPSET_FALSE);
ipset_assignment_set(a2, 2, IPSET_TRUE);
ipset_assignment_set(a2, 3, IPSET_TRUE);
ipset_assignment_set(a2, 4, IPSET_FALSE);
ipset_assignment_cut(a2, 2);
fail_unless(ipset_assignment_equal(a1, a2),
"Assignments should be equal");
ipset_assignment_free(a1);
ipset_assignment_free(a2);
}
END_TEST
START_TEST(test_bdd_assignment_expand_3)
{
ipset_assignment_t *a;
a = ipset_assignment_new();
ipset_assignment_set(a, 0, TRUE);
ipset_assignment_set(a, 2, FALSE);
ipset_expanded_assignment_t *it;
it = ipset_assignment_expand(a, 3);
GByteArray *ea = g_byte_array_sized_new(1);
memset(ea->data, 0, 1);
fail_if(it->finished,
"Expanded assignment shouldn't be empty");
IPSET_BIT_SET(ea->data, 0, TRUE);
IPSET_BIT_SET(ea->data, 1, FALSE);
IPSET_BIT_SET(ea->data, 2, FALSE);
fail_unless(memcmp(ea->data, it->values->data, 1) == 0,
"Expanded assignment 1 doesn't match");
ipset_expanded_assignment_advance(it);
fail_if(it->finished,
"Expanded assignment should have at least 1 element");
IPSET_BIT_SET(ea->data, 0, TRUE);
IPSET_BIT_SET(ea->data, 1, TRUE);
IPSET_BIT_SET(ea->data, 2, FALSE);
fail_unless(memcmp(ea->data, it->values->data, 1) == 0,
"Expanded assignment 2 doesn't match");
ipset_expanded_assignment_advance(it);
fail_unless(it->finished,
"Expanded assignment should have 2 elements");
g_byte_array_free(ea, TRUE);
ipset_expanded_assignment_free(it);
ipset_assignment_free(a);
}
/**
* Add the given node ID to the node stack, and trace down from it
* until we find a terminal node. Assign values to the variables for
* each nonterminal that encounter along the way. We check low edges
* first, so each new variable we encounter will be assigned FALSE.
* (The high edges will be checked eventually by a call to the
* ipset_bdd_iterator_advance() function.)
*/
static void
add_node(struct ipset_bdd_iterator *iterator, ipset_node_id node_id)
{
/* Keep tracing down low edges until we reach a terminal. */
while (ipset_node_get_type(node_id) == IPSET_NONTERMINAL_NODE) {
/* Add this nonterminal node to the stack, and trace down
* further into the tree. We check low edges first, so set the
* node's variable to FALSE in the assignment. */
struct ipset_node *node =
ipset_node_cache_get_nonterminal(iterator->cache, node_id);
cork_array_append(&iterator->stack, node_id);
ipset_assignment_set(iterator->assignment, node->variable, false);
node_id = node->low;
}
/* Once we find a terminal node, save it away in the iterator result
* and return. */
iterator->value = ipset_terminal_value(node_id);
}
static void
process_assignment(struct ipset_iterator *iterator)
{
while (!iterator->bdd_iterator->finished) {
if (iterator->bdd_iterator->value == iterator->desired_value) {
/* If the BDD iterator hasn't finished, and the result of
* the function with this assignment matches what the caller
* wants, then we've found an assignment to generate IP
* addresses from.
*
* Try to expand this assignment, and process the first
* expanded assignment. We want 32 + 1 variables if the
* current address is IPv4; 128 + 1 if it's IPv6. */
DEBUG("Got a matching BDD assignment");
enum ipset_tribool address_type = ipset_assignment_get
(iterator->bdd_iterator->assignment, 0);
if (address_type == IPSET_FALSE) {
/* FALSE means IPv6*/
DEBUG("Assignment is IPv6");
iterator->multiple_expansion_state = IPSET_ITERATOR_NORMAL;
expand_ipv6(iterator);
return;
} else if (address_type == IPSET_TRUE) {
/* TRUE means IPv4*/
DEBUG("Assignment is IPv4");
iterator->multiple_expansion_state = IPSET_ITERATOR_NORMAL;
expand_ipv4(iterator);
return;
} else {
/* EITHER means that this assignment contains both IPv4
* and IPv6 addresses. Expand it as IPv4 first. */
DEBUG("Assignment is both IPv4 and IPv6");
DEBUG("Expanding IPv4 first");
iterator->multiple_expansion_state =
IPSET_ITERATOR_MULTIPLE_IPV4;
ipset_assignment_set
(iterator->bdd_iterator->assignment, 0, IPSET_TRUE);
expand_ipv4(iterator);
return;
}
}
/* The BDD iterator has a value, but it doesn't match the one we
* want. Advance the BDD iterator and try again. */
DEBUG("Value is %d, skipping", iterator->bdd_iterator->value);
ipset_bdd_iterator_advance(iterator->bdd_iterator);
}
/* If we fall through, then the BDD iterator has finished. That
* means there's nothing left for the set iterator. */
DEBUG("Set iterator is finished");
ipset_expanded_assignment_free(iterator->assignment_iterator);
iterator->assignment_iterator = NULL;
ipset_bdd_iterator_free(iterator->bdd_iterator);
iterator->bdd_iterator = NULL;
iterator->finished = true;
}
