fib6_locate
struct fib6_node *fib6_locate(struct fib6_node *root,
fn = fib6_locate(&table->tb6_root, pfx, plen, NULL, 0, true);
fn = fib6_locate(&table->tb6_root,
fn = fib6_locate(&table->tb6_root, prefix, prefixlen, NULL, 0, true);