NTSTATUS GetNextNdp()

in common/ntb.cpp [350:421]
55 lines of code
17 McCabe index (conditional complexity)

    NTSTATUS GetNextNdp(
        void
    )
    {
        const size_t minDptSize = sizeof(NDP) + 2 * sizeof(DPE);

        if (m_NextNdpIndex == 0)
        {
            return STATUS_NO_MORE_ENTRIES;
        }

        m_CurrentNdpDatagramIndex = 0;
        m_CurrentNdpDatagramCount = 0;

        if ((m_NextNdpIndex < sizeof(NTH)) ||
            ((m_NextNdpIndex + minDptSize) > m_BlockLength))
        {
            NCM_RETURN_IF_NOT_NT_SUCCESS_MSG(STATUS_BAD_DATA, "Bad NDP size #1");
        }

        const NDP & ndpHeader = (const NDP &) *(m_Buffer + m_NextNdpIndex);

        if (ndp_sig != ndpHeader.Signature)
        {
            NCM_RETURN_IF_NOT_NT_SUCCESS_MSG(STATUS_BAD_DATA, "Bad NDP signature");
        }

        if ((ndpHeader.Length < minDptSize) ||
            ((ndpHeader.Length & 0x3) != 0) ||
            ((m_NextNdpIndex + ndpHeader.Length) > m_BlockLength))
        {
            NCM_RETURN_IF_NOT_NT_SUCCESS_MSG(STATUS_BAD_DATA, "Bad NDP size #2");
        }

        if ((ndpHeader.NextNdpIndex != 0) &&
            ((ndpHeader.NextNdpIndex < sizeof(NTH)) ||
            ((ndpHeader.NextNdpIndex + minDptSize) > m_BlockLength)))
        {
            NCM_RETURN_IF_NOT_NT_SUCCESS_MSG(STATUS_BAD_DATA, "Bad NDP size #3");
        }

        // scan the table's datagram entries for validity
        // note: if any invalid entries are found, the entire table, and any subsequent tables, are rejected
        UINT32 currentNdpDatagramCount = 0;

        for (size_t offset = sizeof(NDP); offset < ndpHeader.Length; offset += sizeof(DPE))
        {
            const DPE & datagram = (const DPE &) *(m_Buffer + m_NextNdpIndex + offset);

            if (datagram.DatagramIndex == 0 || datagram.DatagramLength == 0)
            {
                m_CurrentNdpIndex = m_NextNdpIndex;
                m_NextNdpIndex = ndpHeader.NextNdpIndex;
                m_CurrentNdpDatagramCount = currentNdpDatagramCount;

                return STATUS_SUCCESS;
            }

            if ((datagram.DatagramIndex < sizeof(NTH)) ||
                (datagram.DatagramIndex > m_BlockLength) ||
                (((UINT64) datagram.DatagramIndex + (UINT64) datagram.DatagramLength) > m_BlockLength))
            {
                NCM_RETURN_IF_NOT_NT_SUCCESS_MSG(STATUS_BAD_DATA, "Bad NDP that not terminates");
            }

            currentNdpDatagramCount++;
        }

        NCM_RETURN_IF_NOT_NT_SUCCESS_MSG(STATUS_BAD_DATA, "Bad NDP size #4");

        return STATUS_BAD_DATA;
    };