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Rewrite the ring buffer code in NPF_TapExForEachOpen function. Now pc…
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…ap_set_snaplen() works well.
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@hsluoyz
hsluoyz committed Mar 18, 2016
1 parent 864c78c commit 4000be9
Showing 1 changed file with 149 additions and 143 deletions.
292 changes: 149 additions & 143 deletions packetWin7/npf/npf/Read.c
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Original file line number Diff line number Diff line change
Expand Up @@ -615,7 +615,7 @@ NPF_TapExForEachOpen(
PUCHAR LookaheadBuffer;
UINT LookaheadBufferSize;
UINT PacketSize;
ULONG TotalLength;
UINT TotalPacketSize;

PMDL pMdl = NULL;
UINT BufferLength;
Expand Down Expand Up @@ -674,7 +674,6 @@ NPF_TapExForEachOpen(
// Get first MDL and data length in the list
//
pMdl = pNetBuf->CurrentMdl;
TotalLength = pNetBuf->DataLength;
Offset = pNetBuf->CurrentMdlOffset;
BufferLength = 0;

Expand Down Expand Up @@ -709,10 +708,6 @@ NPF_TapExForEachOpen(
BufferLength -= Offset;
pEthHeader = (PNDISPROT_ETH_HEADER)((PUCHAR)pEthHeader + Offset);

// As for single MDL (as we assume) condition, we always have BufferLength == TotalLength
if (BufferLength > TotalLength)
BufferLength = TotalLength;

// Handle multiple MDLs situation here, if there's only 20 bytes in the first MDL, then the IP header is in the second MDL.
if (BufferLength == sizeof(NDISPROT_ETH_HEADER) && pMdl->Next != NULL)
{
Expand Down Expand Up @@ -807,8 +802,8 @@ NPF_TapExForEachOpen(
}

//if the filter returns -1 the whole packet must be accepted
if (fres == -1 || fres > PacketSize + HeaderBufferSize)
fres = PacketSize + HeaderBufferSize;
// if (fres == -1 || fres > PacketSize + HeaderBufferSize)
// fres = PacketSize + HeaderBufferSize;

if (Open->mode & MODE_STAT)
{
Expand Down Expand Up @@ -871,6 +866,33 @@ NPF_TapExForEachOpen(

do
{
// Get the whole packet length.
TotalPacketSize = PacketSize + HeaderBufferSize;
PMDL pCurMdl = pMdl;
PMDL pPreMdl;
while (TRUE)
{
pPreMdl = pCurMdl;
NdisGetNextMdl(pPreMdl, &pCurMdl);

if (pCurMdl)
{
NdisQueryMdl(
pCurMdl,
&pEthHeader,
&BufferLength,
NormalPagePriority);
TotalPacketSize += BufferLength;
}
else
{
break;
}
}

if (fres > TotalPacketSize)
fres = TotalPacketSize;

if (fres + sizeof(struct PacketHeader) > LocalData->Free)
{
LocalData->Dropped++;
Expand All @@ -889,167 +911,151 @@ NPF_TapExForEachOpen(
break;
}

/* always true */
if (LookaheadBufferSize + HeaderBufferSize >= fres)
{
PUCHAR pHeaderBuffer = HeaderBuffer;
UINT iFres = fres;

if (withVlanTag)
{
// Insert a tag in the case of IEEE802.1Q packet
pHeaderBuffer = ExAllocatePoolWithTag(NonPagedPool, fres + 4, 'NPCA');
NdisMoveMappedMemory(pHeaderBuffer, HeaderBuffer, 12);
pHeaderBuffer[12] = 0x81;
pHeaderBuffer[13] = 0x00;
NdisMoveMappedMemory(&pHeaderBuffer[14], pVlanTag, 2);
NdisMoveMappedMemory(&pHeaderBuffer[16], &HeaderBuffer[12], fres - 12);
iFres += 4;
}

//
// we do not need to call NdisTransferData, either because we need only the HeaderBuffer, or because the LookaheadBuffer
// contains what we need
//
PUCHAR pHeaderBuffer = HeaderBuffer;
UINT iFres = fres;

Header = (struct PacketHeader *)(LocalData->Buffer + LocalData->P);
LocalData->Accepted++;
GET_TIME(&Header->header.bh_tstamp, &G_Start_Time);
Header->SN = InterlockedIncrement(&Open->WriterSN) - 1;
// Disable the IEEE802.1Q VLAN feature for now.
// if (withVlanTag)
// {
// // Insert a tag in the case of IEEE802.1Q packet
// pHeaderBuffer = ExAllocatePoolWithTag(NonPagedPool, fres + 4, 'NPCA');
// NdisMoveMappedMemory(pHeaderBuffer, HeaderBuffer, 12);
// pHeaderBuffer[12] = 0x81;
// pHeaderBuffer[13] = 0x00;
// NdisMoveMappedMemory(&pHeaderBuffer[14], pVlanTag, 2);
// NdisMoveMappedMemory(&pHeaderBuffer[16], &HeaderBuffer[12], fres - 12);
// iFres += 4;
// }

DbgPrint("MDL %d\n", iFres);
Header = (struct PacketHeader *)(LocalData->Buffer + LocalData->P);
LocalData->Accepted++;
GET_TIME(&Header->header.bh_tstamp, &G_Start_Time);
Header->SN = InterlockedIncrement(&Open->WriterSN) - 1;

Header->header.bh_caplen = iFres;
Header->header.bh_datalen = PacketSize + HeaderBufferSize;
Header->header.bh_hdrlen = sizeof(struct bpf_hdr);
// DbgPrint("MDL %d\n", BufferLength);

LocalData->P += sizeof(struct PacketHeader);
if (LocalData->P == Open->Size)
LocalData->P = 0;
Header->header.bh_caplen = 0;
Header->header.bh_datalen = TotalPacketSize;
Header->header.bh_hdrlen = sizeof(struct bpf_hdr);

//
//we can consider the buffer contiguous, either because we use only the data
//present in the HeaderBuffer, or because HeaderBuffer and LookaheadBuffer are contiguous
// ;-))))))
//
if (Open->Size - LocalData->P < iFres)
{
//the packet will be fragmented in the buffer (aka, it will skip the buffer boundary)
//two copies!!
ToCopy = Open->Size - LocalData->P;
NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pHeaderBuffer, ToCopy);
NdisMoveMappedMemory(LocalData->Buffer + 0, (PUCHAR)pHeaderBuffer + ToCopy, iFres - ToCopy);
LocalData->P = iFres - ToCopy;
}
else
{
//the packet does not need to be fragmented in the buffer (aka, it doesn't skip the buffer boundary)
// ;-)))))) only ONE copy
NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pHeaderBuffer, iFres);
LocalData->P += iFres;
}
LocalData->P += sizeof(struct PacketHeader);
if (LocalData->P == Open->Size)
LocalData->P = 0;

increment = iFres + sizeof(struct PacketHeader);
TotalLength -= iFres;
increment = sizeof(struct PacketHeader);

if (withVlanTag)
//
//we can consider the buffer contiguous, either because we use only the data
//present in the HeaderBuffer, or because HeaderBuffer and LookaheadBuffer are contiguous
// ;-))))))
//
// if (Open->Size - LocalData->P < iFres)
// {
// //the packet will be fragmented in the buffer (aka, it will skip the buffer boundary)
// //two copies!!
// ToCopy = Open->Size - LocalData->P;
// NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pHeaderBuffer, ToCopy);
// NdisMoveMappedMemory(LocalData->Buffer + 0, (PUCHAR)pHeaderBuffer + ToCopy, iFres - ToCopy);
// LocalData->P = iFres - ToCopy;
// }
// else
// {
// //the packet does not need to be fragmented in the buffer (aka, it doesn't skip the buffer boundary)
// // ;-)))))) only ONE copy
// NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pHeaderBuffer, iFres);
// LocalData->P += iFres;
// }

// Disable the IEEE802.1Q VLAN feature for now.
// if (withVlanTag)
// {
// if (pHeaderBuffer)
// {
// ExFreePool(pHeaderBuffer);
// pHeaderBuffer = NULL;
// }
// }

// Add MDLs
pCurMdl = pMdl;
pPreMdl;
while (iFres > 0 || iFres == -1)
{
UINT CopyLengthForMDL = 0;
if (pCurMdl)
{
if (pHeaderBuffer)
NdisQueryMdl(
pCurMdl,
&pEthHeader,
&BufferLength,
NormalPagePriority);

// The first MDL, need to handle the offset.
if (pCurMdl == pMdl)
{
ExFreePool(pHeaderBuffer);
pHeaderBuffer = NULL;
BufferLength -= Offset;
pEthHeader = (PNDISPROT_ETH_HEADER)((PUCHAR)pEthHeader + Offset);
}
}

// add next MDLs
while (TRUE)
{
PMDL pNextMdl = NULL;
NdisGetNextMdl(pMdl, &pNextMdl);
if (iFres != -1)
CopyLengthForMDL = min(iFres, BufferLength);
else
CopyLengthForMDL = BufferLength;

if (pNextMdl)
if (Open->Size - LocalData->P >= BufferLength)
{
NdisQueryMdl(
pNextMdl,
&pEthHeader,
&BufferLength,
NormalPagePriority);

if (BufferLength >= TotalLength)
BufferLength = TotalLength;

if (Open->Size - LocalData->P >= BufferLength)
{
NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pEthHeader, BufferLength);
LocalData->P += BufferLength;

increment += BufferLength;
TotalLength -= BufferLength;

Header->header.bh_caplen += BufferLength;
Header->header.bh_datalen += BufferLength;

DbgPrint("next MDL %d and added\n", BufferLength);

pMdl = pNextMdl;
}
else
{
//the MDL data will be fragmented in the buffer (aka, it will skip the buffer boundary)
//two copies!!
ToCopy = Open->Size - LocalData->P;
NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pEthHeader, ToCopy);
NdisMoveMappedMemory(LocalData->Buffer + 0, (PUCHAR)pEthHeader + ToCopy, BufferLength - ToCopy);
LocalData->P = BufferLength - ToCopy;
NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pEthHeader, CopyLengthForMDL);
LocalData->P += CopyLengthForMDL;

increment += BufferLength;
TotalLength -= BufferLength;

Header->header.bh_caplen += BufferLength;
Header->header.bh_datalen += BufferLength;

DbgPrint("next MDL %d added (two copies)\n", BufferLength);

pMdl = pNextMdl;
}
DbgPrint("iFres = %d, MdlSize = %d, CopyLengthForMDL = %d\n", iFres, BufferLength, CopyLengthForMDL);
}
else
{
break;
//the MDL data will be fragmented in the buffer (aka, it will skip the buffer boundary)
//two copies!!
ToCopy = Open->Size - LocalData->P;
NdisMoveMappedMemory(LocalData->Buffer + LocalData->P, pEthHeader, ToCopy);
NdisMoveMappedMemory(LocalData->Buffer + 0, (PUCHAR)pEthHeader + ToCopy, CopyLengthForMDL - ToCopy);
LocalData->P = CopyLengthForMDL - ToCopy;

DbgPrint("iFres = %d, MdlSize = %d, CopyLengthForMDL = %d (two copies)\n", iFres, BufferLength, CopyLengthForMDL);
}
}

DbgPrint("Packet Header: bh_caplen = %d, bh_datalen = %d\n", Header->header.bh_caplen, Header->header.bh_datalen);

if (Open->Size - LocalData->P < sizeof(struct PacketHeader)) //we check that the available, AND contiguous, space in the buffer will fit
increment += CopyLengthForMDL;
Header->header.bh_caplen += CopyLengthForMDL;
if (iFres != -1)
iFres -= CopyLengthForMDL;
}
else
{
//the NewHeader structure, at least, otherwise we skip the producer
increment += Open->Size - LocalData->P; //at the beginning of the buffer (p = 0), and decrement the free bytes appropriately
LocalData->P = 0;
break;
}

InterlockedExchangeAdd(&LocalData->Free, (ULONG)(-(LONG)increment));
if (Open->Size - LocalData->Free >= Open->MinToCopy)
pPreMdl = pCurMdl;
NdisGetNextMdl(pPreMdl, &pCurMdl);
}

DbgPrint("Packet Header: bh_caplen = %d, bh_datalen = %d\n", Header->header.bh_caplen, Header->header.bh_datalen);

if (Open->Size - LocalData->P < sizeof(struct PacketHeader)) //we check that the available, AND contiguous, space in the buffer will fit
{
//the NewHeader structure, at least, otherwise we skip the producer
increment += Open->Size - LocalData->P; //at the beginning of the buffer (p = 0), and decrement the free bytes appropriately
LocalData->P = 0;
}

InterlockedExchangeAdd(&LocalData->Free, (ULONG)(-(LONG)increment));
if (Open->Size - LocalData->Free >= Open->MinToCopy)
{
if (Open->mode & MODE_DUMP)
NdisSetEvent(&Open->DumpEvent);
else
{
if (Open->mode & MODE_DUMP)
NdisSetEvent(&Open->DumpEvent);
else
if (Open->ReadEvent != NULL)
{
if (Open->ReadEvent != NULL)
{
KeSetEvent(Open->ReadEvent, 0, FALSE);
}
KeSetEvent(Open->ReadEvent, 0, FALSE);
}
}

break;
}
else // never comes here.
{
IF_LOUD(DbgPrint("NPF_tapExForEachOpen: This is an error !!!!\n");)
//ndisTransferData required
//This is an error !!
break;
}
} while (FALSE);

Expand Down

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