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;
}
/**
* Find the highest non-EITHER bit in an assignment, starting from the
* given bit index.
*/
static unsigned int
find_last_non_either_bit(struct ipset_assignment *assignment,
unsigned int starting_bit)
{
unsigned int i;
for (i = starting_bit; i >= 1; i--) {
enum ipset_tribool value = ipset_assignment_get(assignment, i);
if (value != IPSET_EITHER) {
return i;
}
}
return 0;
}
static guint
find_last_non_either_bit(ipset_assignment_t *assignment,
guint starting_bit)
{
guint i;
for (i = starting_bit; i >= 1; i--)
{
ipset_tribool_t value = ipset_assignment_get(assignment, i);
if (value != IPSET_EITHER)
{
return i;
}
}
return 0;
}
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;
}
