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229 lines
9.0 KiB
229 lines
9.0 KiB
/* protocol.h, /appletalk/ins, Garth Conboy, 10/04/88 */
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/* Copyright (c) 1988 by Pacer Software Inc., La Jolla, CA */
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/* GC - Initial coding.
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GC - (11/24/89): Many changes for AppleTalk phase II -- No more LAP
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orientation.
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GC - (03/30/92): Altered comments to reflect new BufferDescriptor
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transmit buffer scheme.
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*** Make the PVCS source control system happy:
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$Header$
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$Log$
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***
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Definitions for AppleTalk and AARP.
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*/
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/* There are two routines used to send DDP datagrams: TransmitDdp() and
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DeliverDdp(). DeliverDdp takes arguments (amoungst others) of
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"socket" and "destinationAddress". TransmitDdp, on the other hand, takes
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"sourceAddress" and "destinationAddress".
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Both of these routines operate on BufferDescriptors which a chain of
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buffer chunks. These routines prepend link, 802.2 and Ddp headers as
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needed.
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DeliverDdp() can be used to deliver packets within the stack or router;
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it will call the router if needed and present. TransmitDdp() will always
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place a packet on the network; it is called by DeliverDdp() when an actual
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network transmit is required.
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When the router is in operation, it may set a magic bit ("prependInPlace")
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in the BufferDescriptor to alter the function of header forumlation; see
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the comments in "buffdesc.h".
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The AppleTalk stack operates on two basic types of events: an incoming
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packet, and a timer going off. Both of these events are likey to operate
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on the same databases (e.g. an incoming RTMP data packet and the RTMP
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validity timer going off). These events are, no doubt, asynchronous within
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a single process; thus, if we're handing the RTMP validity timer expiration
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and an RTMP data packet comes in and we start handling that instead, the
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data structures could be in a bad state and we would crash and burn. Some
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operating systems (i.e. VMS) avoid this problem by not allowing one of these
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events to interrupt the other (e.g. queuing of events happens for free). If
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the target operating system for this implementation does not assure such
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behaviour, it must be implemented by hand.
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There exist four routines for moderating critical code paths:
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DeferIncomingPackets();
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HandleIncomingPackets();
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DeferTimerChecking();
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HandleDeferredTimerChecks();
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These routines maintain "defer counters" so calls will stack corrected.
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Thus, if five calls are made to "DeferIncomingPackets", file call to
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"HandleIncomingPackets" will also be required to get incoming packet
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handling enabled again.
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If the defer-incoming-packets counter is non-zero when a packet (from any
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of the various port types) comes into DdpPacketIn, it will be queued for
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later handling and processing will continue where it was before the
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untimely interruption. Actually, when the defer-incoming-packets counter
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gets down to zero, via calls to HandleIncomingPackets, any queue of
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deferred packets will be fed back into DdpPacketIn at that time.
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On timers front, before a timer handler is invoked by the timer management
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code, a call to DeferTimerChecking is made, so that additional timers will
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not go off untill a call to HandleDeferredTimerChecks is made. Thus, any
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timer handler MUST call HandleDeferredTimerChecks before it returns.
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Thus, if an incoming packet handler is about to change or examine databases
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that could be altered both by additional incoming packets and by timers
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going off, it should defer both incoming packets and timer interrupts.
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Timer handlers should defer incoming packets as needed.
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*/
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/* The two logical AppleTalk packet types that we need to know about: */
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typedef enum {AppleTalk, AddressResolution} LogicalProtocol;
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/* Maximum link access/hardware address lengths (Ethernet and TokenRing both
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set the same record): */
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#define MaximumHardwareAddressLength EthernetAddressLength
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#define MaximumHeaderLength (TokenRingMaxLinkHeaderLength + \
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Ieee802dot2headerLength)
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#define MaximumRoutingInfoLength TokenRingMaxRoutingBytes
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#define MaximumDdpDatagramSize 586
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#define MaximumLongDdpPacketSize 600 /* Really 599, but even is nicer */
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#define MaximumShortDdpPacketSize 592 /* Again, really 591 */
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/* Define temporary buffer sizes, these must be big enough to hold both all
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of the packet data plus any link/hardware headers... */
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#define MaximumPacketSize (MaximumHeaderLength + \
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MaximumLongDdpPacketSize)
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/* Network number information. */
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#define FirstValidNetworkNumber 0x0001
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#define LastValidNetworkNumber 0xFFFE
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#define FirstStartupNetworkNumber 0xFF00
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#define LastStartupNetworkNumber 0xFFFE
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#define NullNetworkNumber 0x0000
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#define UnknownNetworkNumber NullNetworkNumber
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#define CableWideBroadcastNetworkNumber NullNetworkNumber
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#if not InitializeData
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extern
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#endif
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AppleTalkNetworkRange startupNetworkRange
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#if InitializeData
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= {FirstStartupNetworkNumber, LastStartupNetworkNumber};
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#else
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;
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#endif
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/* DDP packet offsets (skipping Link/Hardware headers): */
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#define ShortDdpHeaderLength 5
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#define ShortDdpLengthOffset 0
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#define ShortDdpDestSocketOffset 2
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#define ShortDdpSourceSocketOffset 3
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#define ShortDdpProtocolTypeOffset 4
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#define ShortDdpDatagramOffset 5
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#define LongDdpHeaderLength 13
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#define LongDdpLengthOffset 0
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#define LongDdpChecksumOffset 2
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#define LongDdpDestNetworkOffset 4
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#define LongDdpSourceNetworkOffset 6
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#define LongDdpDestNodeOffset 8
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#define LongDdpSourceNodeOffset 9
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#define LongDdpDestSocketOffset 10
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#define LongDdpSourceSocketOffset 11
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#define LongDdpProtocolTypeOffset 12
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#define LongDdpDatagramOffset 13
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#define LeadingUnChecksumedBytes 4
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#define LongDdpHopCountMask 0x3C
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/* Offsets within a DDP datagram: */
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#define RtmpRequestCommandOffset 0
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#define RtmpSendersNetworkOffset 0
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#define RtmpSendersIdLengthOffset 2
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#define RtmpSendersIdOffset 3
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#define RtmpRangeStartOffset 4
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#define RtmpRangeEndOffset 7
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#define ZipCommandOffset 0
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#define ZipNetworkCountOffset 1
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#define ZipFlagsOffset 1
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#define ZipFirstNetworkOffset 2 /* For ZIP query/reply */
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#define ZipFirstZoneLengthOffset 4
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#define ZipLastNetworkOffset 4 /* For ZIP query/reply */
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#define ZipFirstZoneNameOffset 5
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#define ZipRequestedZoneLengthOffset 6 /* For ZIP query/reply */
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#define ZipRequestedZoneNameOffset 7 /* For ZIP query/reply */
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#define ZipCableRangeStartOffset 2 /* AppleTalk phase II offsets */
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#define ZipCableRangeEndOffset 4
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#define ZipZoneLengthOffset 6
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#define ZipOldZoneLengthOffset 6
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#define ZipZoneNameOffset 7
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#define ZipOldZoneNameOffset 7
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#define AtpCommandControlOffset 0
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#define AtpBitmapOffset 1
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#define AtpSequenceNumberOffset 1
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#define AtpTransactionIdOffset 2
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#define AtpUserBytesOffset 4
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#define AtpDataOffset 8
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#define AtpHeaderSize AtpDataOffset
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#define EpCommandOffset 0
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#define NbpControlOffset 0
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#define NbpIdOffset 1
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#define NbpFirstTupleOffset 2
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/* DDP protocol types: */
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#define DdpProtocolRtmpResponseOrData 1
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#define DdpProtocolNbp 2
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#define DdpProtocolAtp 3
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#define DdpProtocolEp 4
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#define DdpProtocolRtmpRequest 5
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#define DdpProtocolZip 6
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#define DdpProtocolAdsp 7
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/* AppleTalk node number info: */
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#define AnyRouterNodeNumber 0
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#define UnknownNodeNumber 0
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#define MaximumAppleTalkNodes 256
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#define MinimumUsableAppleTalkNode 1
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#define MaximumUsableAppleTalkNode 254
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#define MaximumExtendedAppleTalkNode 253
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#define HighestWorkstationNodeNumber 127
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#define LowestServerNodeNumber 128
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#define AppleTalkBroadcastNodeNumber ((unsigned char)0xFF)
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/* A few structures for implementing AppleTalk addresses (for lack of any
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better place to put them): */
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typedef struct {short unsigned networkNumber;
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char unsigned nodeNumber;
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} ExtendedAppleTalkNodeNumber;
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/* Hashing algorithum for various uses. Make sure we're positive [thus the
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shift by 7 rather than 8]. Only hash node and socket; due to the "zero
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matches all" for non-extended network numbers. */
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#define HashAppleTalkAddress(address) \
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((short unsigned)((address.nodeNumber << 7) + \
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(address.socketNumber & 0x7F)))
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/* Hash for an extended node number. Again, always positive. */
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#define HashExtendedAppleTalkNode(address) \
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((short unsigned)((address.networkNumber & 0x3FFF) + \
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address.nodeNumber))
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