HCI_LINK_POLICY_ENABLE_SNIFF_MODE
unit->hci_lmp_mask |= HCI_LINK_POLICY_ENABLE_SNIFF_MODE;
if (opt_sniff > 0) val |= HCI_LINK_POLICY_ENABLE_SNIFF_MODE;
if (opt_sniff < 0) val &= ~HCI_LINK_POLICY_ENABLE_SNIFF_MODE;
if (val & HCI_LINK_POLICY_ENABLE_SNIFF_MODE) tag("sniff");