NdisAllocateNetBufferListContext

NTDEV
1

Hi all.
I’m using NdisAllocateNetBufferListContext to allocate a NET_BUFFER_LIST_CONTEXT for a newly cloned NET_BUFFER_LIST. But this coused a deadlock (IRQL not less than or equal to). For this alocation, I use the NET_BUFFER_LIST_CONTEXT size of the source NET_BUFFER_LIST. I think this function (NdisAllocateNetBufferListContext) is being called at (IRQL>=Dispatchlevel) and the original NET_BUFFER has been unloaded (or part of that structure). So, if I’m right, what should I do? How to temporarily reduce IRQL, and then increase it.

… FilterSendNetBufferList(…, PNET_BUFFER_LIST pNBL, …)
{
…
…
cloneNBL = NdisAllocateCloneNetBufferList(pNBL, …);
NdisAllocateNetBufferListContext(cloneNBL, NET_BUFFER_LIST_CONTEXT_DATA_SIZE(pNBL),…);

 RtlCopy (cloneNBL->Context->ContextData, NET_BUFFER_LIST_CONTEXT_DATA_START(pNBL),
                                                             NET_BUFFER_LIST_CONTEXT_DATA_SIZE(pNBL),

}

And the second question.
So far I was cloning NET_BUFFER_LIST without any context structure and was sending that newly cloned NBL over the network, insteed of original NBL. As a result, I was able to ping from one host to another. But other more complex protocols didn’t work properly. In particular, I couldn’t see the shared directory on the other host when my driver was loaded. Is it due to missing NET_BUFFER_LIST_CONTEXT data?
Thank you.

2

Thanks everybody. Problem was in NULL pointer;

3

Hello everybody.
Who can help me.
Thes couses blue screen DRIVER IRQL NOT less OR equal

VOID FilterSendNetBufferLists(NDIS_HANDLE FilterModuleContext, PNET_BUFFER_LIST NetBufferLists, NDIS_PORT_NUMBER PortNumber, ULONG SendFlags)
{

                RtlCopyMemory((PUCHAR)pFilter->pIrpSend[nSend]->AssociatedIrp.SystemBuffer + 1, (PUCHAR)MmGetMdlVirtualAddress(NET_BUFFER_FIRST_MDL(pNB)) + NET_BUFFER_DATA_OFFSET(pNB), NET_BUFFER_DATA_LENGTH(pNB));
                if (pNB == NET_BUFFER_LIST_FIRST_NB(pNBL)) {
                    PNET_BUFFER_LIST cloneOfpNBL = NdisAllocateCloneNetBufferList(pNBL, pFilter->NBLPoolHandle, pFilter->NBPoolHandle, NDIS_CLONE_FLAGS_USE_ORIGINAL_MDLS);//osr how_to_send_cloned_nbl
                    if (!cloneOfpNBL) { KdPrint(("Error NdisAllocateCloneNetBufferList")); FILTER_RELEASE_LOCK(&pFilter->Lock, DispatchLevel); break; }  //????
                    pNBL->ChildRefCount = 0;                              //new from community "How-to-send-cloned-nbl"
                    cloneOfpNBL->ParentNetBufferList = NULL;   //pNBL;            //new from community "How-to-send-cloned-nbl"

                    NET_BUFFER* pCloneNB = NET_BUFFER_LIST_FIRST_NB(cloneOfpNBL);
                    while (pCloneNB) {

                        pCloneNB->MdlChain = NULL;
                        pCloneNB = NET_BUFFER_NEXT_NB(pCloneNB);
                    }

                  **  if (pNBL->Context) {
                        NDIS_STATUS resContext = NdisAllocateNetBufferListContext(cloneOfpNBL,
                            NET_BUFFER_LIST_CONTEXT_DATA_SIZE(pNBL),
                            0, FILTER_TAG/*'2gaT'*/);
                        if (resContext != NDIS_STATUS_SUCCESS) {
                            FILTER_RELEASE_LOCK(&pFilter->Lock, DispatchLevel);
                            if (resContext == NDIS_STATUS_RESOURCES) { KdPrint(("NdisAllocateNetBufferListContext error NDIS_STATUS_RESOURCES\n")); }
                            else { KdPrint(("NdisAllocateNetBufferListContext error\n")); }
                            break;
                        }

                        cloneOfpNBL->Context->Next = 0;
                        cloneOfpNBL->Context->Offset = pNBL->Context->Offset;
                        cloneOfpNBL->Context->Size = pNBL->Context->Size;
                        RtlCopyMemory(NET_BUFFER_LIST_CONTEXT_DATA_START(cloneOfpNBL), NET_BUFFER_LIST_CONTEXT_DATA_START(pNBL), NET_BUFFER_LIST_CONTEXT_DATA_SIZE(pNBL));
                    }**

}