windows-nt/Source/XPSP1/NT/net/netbeui/sys/nbfmac.c
2020-09-26 16:20:57 +08:00

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/*++
Copyright (c) 1989, 1990, 1991 Microsoft Corporation
Module Name:
nbfmac.c
Abstract:
This module contains code which implements Mac type dependent code for
the NBF transport.
Author:
David Beaver (dbeaver) 1-July-1991
Environment:
Kernel mode (Actually, unimportant)
Revision History:
--*/
#include "precomp.h"
#pragma hdrstop
UCHAR SingleRouteSourceRouting[] = { 0xc2, 0x70 };
UCHAR GeneralRouteSourceRouting[] = { 0x82, 0x70 };
ULONG DefaultSourceRoutingLength = 2;
//
// This is the interpretation of the length bits in
// the 802.5 source-routing information.
//
ULONG SR802_5Lengths[8] = { 516, 1500, 2052, 4472,
8144, 11407, 17800, 17800 };
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE,MacInitializeMacInfo)
#pragma alloc_text(PAGE,MacSetNetBIOSMulticast)
#endif
VOID
MacInitializeMacInfo(
IN NDIS_MEDIUM MacType,
IN BOOLEAN UseDix,
OUT PNBF_NDIS_IDENTIFICATION MacInfo
)
/*++
Routine Description:
Fills in the MacInfo table based on MacType.
Arguments:
MacType - The MAC type we wish to decode.
UseDix - TRUE if we should use DIX encoding on 802.3.
MacInfo - The MacInfo structure to fill in.
Return Value:
None.
--*/
{
switch (MacType) {
case NdisMedium802_3:
MacInfo->DestinationOffset = 0;
MacInfo->SourceOffset = 6;
MacInfo->SourceRouting = FALSE;
MacInfo->AddressLength = 6;
if (UseDix) {
MacInfo->TransferDataOffset = 3;
MacInfo->MaxHeaderLength = 17;
MacInfo->MediumType = NdisMediumDix;
} else {
MacInfo->TransferDataOffset = 0;
MacInfo->MaxHeaderLength = 14;
MacInfo->MediumType = NdisMedium802_3;
}
MacInfo->MediumAsync = FALSE;
break;
case NdisMedium802_5:
MacInfo->DestinationOffset = 2;
MacInfo->SourceOffset = 8;
MacInfo->SourceRouting = TRUE;
MacInfo->AddressLength = 6;
MacInfo->TransferDataOffset = 0;
MacInfo->MaxHeaderLength = 32;
MacInfo->MediumType = NdisMedium802_5;
MacInfo->MediumAsync = FALSE;
break;
case NdisMediumFddi:
MacInfo->DestinationOffset = 1;
MacInfo->SourceOffset = 7;
MacInfo->SourceRouting = FALSE;
MacInfo->AddressLength = 6;
MacInfo->TransferDataOffset = 0;
MacInfo->MaxHeaderLength = 13;
MacInfo->MediumType = NdisMediumFddi;
MacInfo->MediumAsync = FALSE;
break;
case NdisMediumWan:
MacInfo->DestinationOffset = 0;
MacInfo->SourceOffset = 6;
MacInfo->SourceRouting = FALSE;
MacInfo->AddressLength = 6;
MacInfo->TransferDataOffset = 0;
MacInfo->MaxHeaderLength = 14;
MacInfo->MediumType = NdisMedium802_3;
MacInfo->MediumAsync = TRUE;
break;
default:
ASSERT(FALSE);
}
}
VOID
MacConstructHeader (
IN PNBF_NDIS_IDENTIFICATION MacInfo,
IN PUCHAR Buffer,
IN PUCHAR DestinationAddress,
IN PUCHAR SourceAddress,
IN UINT PacketLength,
IN PUCHAR SourceRouting,
IN UINT SourceRoutingLength,
OUT PUINT HeaderLength
)
/*++
Routine Description:
This routine is called to construct the Mac header for the particular
network type we're talking to.
Arguments:
MacInfo - Describes the mac we wish to build a header for.
Buffer - Where to build the header.
DestinationAddress - the address this packet is to be sent to.
SourceAddress - Our address. Passing it in as a parameter allows us to play
games with source if we need to.
PacketLength - The length of this packet. Note that this does not
includes the Mac header.
SourceRouting - Optional source routing information.
SourceRoutingLength - The length of SourceRouting.
HeaderLength - Returns the length of the constructed header.
Return Value:
None.
--*/
{
//
// Note network order of bytes.
//
switch (MacInfo->MediumType) {
case NdisMedium802_3:
*(ULONG UNALIGNED *)&Buffer[6] = *(ULONG UNALIGNED *)&SourceAddress[0];
Buffer[10] = SourceAddress[4];
Buffer[11] = SourceAddress[5];
*(ULONG UNALIGNED *)&Buffer[0] = *(ULONG UNALIGNED *)&DestinationAddress[0];
Buffer[4] = DestinationAddress[4];
Buffer[5] = DestinationAddress[5];
Buffer[12] = (UCHAR)(PacketLength >> 8);
Buffer[13] = (UCHAR)PacketLength;
*HeaderLength = 14;
break;
case NdisMediumDix:
*(ULONG UNALIGNED *)&Buffer[6] = *(ULONG UNALIGNED *)&SourceAddress[0];
Buffer[10] = SourceAddress[4];
Buffer[11] = SourceAddress[5];
*(ULONG UNALIGNED *)&Buffer[0] = *(ULONG UNALIGNED *)&DestinationAddress[0];
Buffer[4] = DestinationAddress[4];
Buffer[5] = DestinationAddress[5];
Buffer[12] = 0x80;
Buffer[13] = 0xd5;
Buffer[14] = (UCHAR)(PacketLength >> 8);
Buffer[15] = (UCHAR)PacketLength;
Buffer[16] = 0x00;
*HeaderLength = 17;
break;
case NdisMedium802_5:
Buffer[0] = TR_HEADER_BYTE_0;
Buffer[1] = TR_HEADER_BYTE_1;
ASSERT (TR_ADDRESS_LENGTH == 6);
*(ULONG UNALIGNED *)&Buffer[8] = *(ULONG UNALIGNED *)&SourceAddress[0];
Buffer[12] = SourceAddress[4];
Buffer[13] = SourceAddress[5];
*(ULONG UNALIGNED *)&Buffer[2] = *(ULONG UNALIGNED *)&DestinationAddress[0];
Buffer[6] = DestinationAddress[4];
Buffer[7] = DestinationAddress[5];
*HeaderLength = 14;
if (SourceRouting != NULL) {
RtlCopyMemory (&Buffer[14], SourceRouting, SourceRoutingLength);
Buffer[8] |= 0x80; // add SR bit in source address
*HeaderLength = 14 + SourceRoutingLength;
}
break;
case NdisMediumFddi:
Buffer[0] = FDDI_HEADER_BYTE;
*(ULONG UNALIGNED *)&Buffer[7] = *(ULONG UNALIGNED *)&SourceAddress[0];
Buffer[11] = SourceAddress[4];
Buffer[12] = SourceAddress[5];
*(ULONG UNALIGNED *)&Buffer[1] = *(ULONG UNALIGNED *)&DestinationAddress[0];
Buffer[5] = DestinationAddress[4];
Buffer[6] = DestinationAddress[5];
*HeaderLength = 13;
break;
default:
PANIC ("MacConstructHeader: PANIC! called with unsupported Mac type.\n");
// This should not happen - but just in case
*HeaderLength = 0;
}
}
VOID
MacReturnMaxDataSize(
IN PNBF_NDIS_IDENTIFICATION MacInfo,
IN PUCHAR SourceRouting,
IN UINT SourceRoutingLength,
IN UINT DeviceMaxFrameSize,
IN BOOLEAN AssumeWorstCase,
OUT PUINT MaxFrameSize
)
/*++
Routine Description:
This routine returns the space available for user data in a MAC packet.
This will be the available space after the MAC header; all LLC and NBF
headers will be included in this space.
Arguments:
MacInfo - Describes the MAC we wish to decode.
SourceRouting - If we are concerned about a reply to a specific
frame, then this information is used.
SourceRouting - The length of SourceRouting.
MaxFrameSize - The maximum frame size as returned by the adapter.
AssumeWorstCase - TRUE if we should be pessimistic.
MaxDataSize - The maximum data size computed.
Return Value:
None.
--*/
{
switch (MacInfo->MediumType) {
case NdisMedium802_3:
//
// For 802.3, we always have a 14-byte MAC header.
//
*MaxFrameSize = DeviceMaxFrameSize - 14;
break;
case NdisMediumDix:
//
// For DIX, we have the 14-byte MAC header plus
// the three-byte DIX header.
//
*MaxFrameSize = DeviceMaxFrameSize - 17;
break;
case NdisMedium802_5:
//
// For 802.5, if we have source routing information then
// use that, otherwise assume the worst if told to.
//
if (SourceRouting && SourceRoutingLength >= 2) {
UINT SRLength;
SRLength = SR802_5Lengths[(SourceRouting[1] & 0x70) >> 4];
DeviceMaxFrameSize -= (SourceRoutingLength + 14);
if (DeviceMaxFrameSize < SRLength) {
*MaxFrameSize = DeviceMaxFrameSize;
} else {
*MaxFrameSize = SRLength;
}
} else {
if (!AssumeWorstCase) {
*MaxFrameSize = DeviceMaxFrameSize - 16;
} else if (DeviceMaxFrameSize < (544+sizeof(DLC_FRAME)+sizeof(NBF_HDR_CONNECTIONLESS))) {
*MaxFrameSize = DeviceMaxFrameSize - 32;
} else {
*MaxFrameSize = 512 + sizeof(DLC_FRAME) + sizeof(NBF_HDR_CONNECTIONLESS);
}
}
break;
case NdisMediumFddi:
//
// For FDDI, we always have a 13-byte MAC header.
//
*MaxFrameSize = DeviceMaxFrameSize - 13;
break;
}
}
VOID
MacSetNetBIOSMulticast (
IN NDIS_MEDIUM Type,
IN PUCHAR Buffer
)
/*++
Routine Description:
This routine sets the NetBIOS broadcast address into a buffer provided
by the user.
Arguments:
Type the Mac Medium type.
Buffer the buffer to put the multicast address in.
Return Value:
none.
--*/
{
switch (Type) {
case NdisMedium802_3:
case NdisMediumDix:
Buffer[0] = 0x03;
Buffer[ETHERNET_ADDRESS_LENGTH-1] = 0x01;
break;
case NdisMedium802_5:
Buffer[0] = 0xc0;
Buffer[TR_ADDRESS_LENGTH-1] = 0x80;
break;
case NdisMediumFddi:
Buffer[0] = 0x03;
Buffer[FDDI_ADDRESS_LENGTH-1] = 0x01;
break;
default:
PANIC ("MacSetNetBIOSAddress: PANIC! called with unsupported Mac type.\n");
}
}