/* Check whether the TxCb is still a valid control block in the instance's retry list. */
BOOLEAN Dhcp6IsValidTxCb(IN DHCP6_INSTANCE *Instance, IN DHCP6_TX_CB *TxCb)
/* Check whether the TxCb is still a valid control block in the instance's retry list. */
BOOLEAN Dhcp6IsValidTxCb(IN DHCP6_INSTANCE *Instance, IN DHCP6_TX_CB *TxCb)
{
  LIST_ENTRY  *Entry;
  NET_LIST_FOR_EACH (Entry, &Instance->TxList) {
    if (TxCb == NET_LIST_USER_STRUCT (Entry, DHCP6_TX_CB, Link)) {
      return TRUE;
    }
  }
  return FALSE;
}