问个问题

如果在passthru中对payload进行加密，由于原始数据长度接近MTU，加密后长度超过1500，此时需要对package进行fragment，应该如何处理？

多谢。

自己回答吧，http://bbs.driverdevelop.com/read.php?tid=12522，虽然我对驱动了解不深，但以为构造pmtu，似乎不是那么的稳妥，比如发送pmtu的时机等等，尤须思考。

顺便贴个别人的ipsec的source code，http://blog.csdn.net/Mycro/archive/2006/03/01/613195.aspx

再来一个，那谁谁写的psudo code。

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I thought that is answer for my problem eventually, copy from yahoo group.

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
You need to filter the OID_GEN_MAXIMUM_TOTAL_SIZE and
OID_GEN_MAXIMUM_FRAME_SIZE queries in the completion path. There you will
see the values returned by the lower-level NIC. Stash these, and remember
that they can be greater than 1514 and 1500 for 1Gbe NICs with Jumbo frames.
Modify the value returned to higher-level protocols by subtracting the
length of your extra header. Verify that you have made this mod correctly
using OIDScope.

Ohooooooooo,  code also givennnnnnnnnnnn.

if (Oid == OID_GEN_MAXIMUM_FRAME_SIZE && ConfigData.LanMTU && !Adapter->bWanAdapter)
{
    if (IMReqBuffer->ReqBuffer.RequestType == NdisRequestQueryInformation)
    {
        if (IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.InformationBufferLength == sizeof(INT))
        {
            INT OrgSize =
                *((PULONG)IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.InformationBuffer);
            if (OrgSize > ConfigData.LanMTU)
            {
                *((PULONG)IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.InformationBuffer) = ConfigData.LanMTU;
                IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.BytesWritten = sizeof(INT);
                ImDbgOut(DBG_INFO, DBG_INIT, ("Spoofing FRAME_SIZE for %.08X: %d, %d\n", Adapter, ConfigData.LanMTU, OrgSize));
            }
            else
            {
                ImDbgOut(DBG_INFO, DBG_INIT, ("NOT Spoofing FRAME_SIZE for %.08X: %d, %d\n", Adapter, ConfigData.LanMTU, OrgSize));
            }
        }
    }
}

if (Oid == OID_GEN_MAXIMUM_TOTAL_SIZE && ConfigData.LanMTU && !Adapter->bWanAdapter)
{
    if (IMReqBuffer->ReqBuffer.RequestType == NdisRequestQueryInformation)
    {
        if (IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.InformationBufferLength == sizeof(INT))
        {
            INT OrgSize =
                *((PULONG)IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.InformationBuffer);
            INT Size = Adapter->TotalSize ? Adapter->TotalSize : MAXETH8023LEN;
            if (OrgSize > Size && ConfigData.LanMTU)
            {
                Size -= MAXETH8023LEN - ConfigData.LanMTU;
                *((PULONG)IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.InformationBuffer) = Size;
                IMReqBuffer->ReqBuffer.DATA.QUERY_INFORMATION.BytesWritten = sizeof(INT);
                ImDbgOut(DBG_INFO, DBG_INIT, ("Spoofing TOTAL_SIZE for %.08X: %d (%d, %d, %d)\n",
                    Adapter, Size, Adapter->TotalSize, ConfigData.LanMTU, OrgSize));
            }
            else
            {
                ImDbgOut(DBG_INFO, DBG_INIT,
                    ("NOT Spoofing TOTAL_SIZE for %.08X: %d (%d, %d, %d)\n", Adapter, Size, Adapter->TotalSize, ConfigData.LanMTU, OrgSize));
            }
        }
    }
}