ipfw_insn_nat
action->len = F_INSN_SIZE(ipfw_insn_nat);
t = ((ipfw_insn_nat *)cmd)->nat;
((ipfw_insn_nat *)cmd)->nat = t;
ipfw_insn_nat *cmd;
cmd = (ipfw_insn_nat *)ipfw_get_action(chain->map[i]);
if (cmdlen != F_INSN_SIZE(ipfw_insn_nat))