ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng)/ProfitPress-MegaCDROM2.B6I/MISC/NETWORK/PCRTE220.ZIP/ETHER.INC

Text File | 1991-02-19 | 9.6 KB | 283 lines

;;*****************************************************************************
;;                        ether.inc           ether.inc
;;*****************************************************************************
;;
;;  Copyright (C) 1989 Northwestern University, Vance Morrison
;;
;;
;; Permission to view, compile, and modify for LOCAL (intra-organization)
;; USE ONLY is hereby granted, provided that this copyright and permission
;; notice appear on all copies.  Any other use by permission only.
;;
;; Northwestern University makes no representations about the suitability
;; of this software for any purpose.  It is provided "as is" without expressed
;; or implied warranty.  See the copywrite notice file for complete details.
;;
;;*****************************************************************************
;;
;; ether.inc constains the board independant, ethernet processing that needs
;; to be done.  I rely only on the IF interface defined in if.inc.
;;
;; The functions provided by this file are
;;
;;   ETH_DECLARE name, interface, task
;;   ETH_DEFINE name
;;   ETH_R_READ name, type, code_label
;;   ETH_R_RETURN name
;;   ETH_R_CONT_in_BX_CX_ES_const_BX_CX_DX_BP_SI_DI_ES name, ok
;;   ETH_W_ACCESS_in_CX_out_DI_ES_const_BX_CX_BP name, no_buffer
;;   ETH_W_WRITE_in_AX_CX_SI_DI_ES_const_BX_BP_ES name
;;   ETH_IS_BROADCAST_in_BX_ES_const_AX_BX_CX_DX_BP_DI_ES name
;;   ETH_COPY_in_CX_SI_DI_ES_out_SI_DI_const_BX_BP_ES name
;;
;;  Variables Provided by this module (READ ONLY!!!!)
;;
;;      eth_&name&_declared     1 if this module is declared
;;      eth_&name&_address      The hardware address
;;      eth_&name&_mtu          The maximum transmission unit
;;
;;*****************************************************************************


;;*****************************************************************************
;; defs for ethernet structures

IP_TYPE             = 0800h
SWAPPED_IP_TYPE     = 0008h
ARP_TYPE            = 0806h
SWAPPED_ARP_TYPE    = 0608h

ether   STRUC
    ether_dst       DB 6 DUP (0)
    ether_src       DB 6 DUP (0)
    ether_type      DW 0
ether   ENDS

;;*****************************************************************************
;; data storage needed by this module

eth_data STRUC
    eth_type_tab    dw 256 dup (0)
    eth_w_try       db ?
eth_data ENDS


;;*****************************************************************************
;;   ETH_DECLARE name, interface, task
;;       creates a new data link  object.  'name' is the name of this new
;;       object.  'interface' is the name of the interface to that will provide
;;       the low level services this module will need.  'task' is the name
;;       of a task that we need
;;
ETH_DECLARE MACRO name, interface, task
    .errb <task>

    .DATA
    eth_&name&_declared     = 1
    eth_&name&_interface    = interface
    eth_&name&_task         = task
    eth_&name&_address      = if_&interface&_address
    eth_&name&_mtu          = 1500              ;; maximum transmission unit

    global eth_&name&_data:eth_data
    .CODE
    global eth_&name&_continue:near
    global eth_&name&_real_define:near
ENDM


;;*****************************************************************************
;;   ETH_DEFINE name
;;      ETH_DEFINE declare all the things that have to be defined in
;;      every independantly assembled module.  ETH declares those
;;      things that need be be done only once (in particular memory allocation
;;      and initialzation code).  Every module including the one ETH_DEFINE
;;      is in) must have a ETH_DELCARE.
;;
ETH_DEFINE MACRO name

    call eth_&name&_real_define
ENDM

ETH_REAL_DEFINE MACRO name
    local start, around
    .errb <name>

ifdef eth_&name&_declared
    .DATA
    eth_&name&_data  eth_data <>             ;; create storage needed

    .CODE
    jmp around
        start:
        ETH_TASK name
            ;; this does NOT fall through
    around:
    eth_&name&_real_define:
    mov AX, DS                                      ;; initilize table
    mov ES, AX
    mov AX, offset eth_&name&_continue
    mov DI, offset eth_&name&_data.eth_type_tab
    mov CX, 256
    rep
    stosw

    TASK_DEFINE %eth_&name&_task, start          ;; start the task
    RET
endif
ENDM


;;******************************************************************************
;;   ETH_R_READ name, type, code_label
;;      ETH_R_READ declares that code starting at 'code_label' should be
;;      called whenever a packet with type 'type' is read from the IF.
;;      The code is called with BX:ES pointing to the start of the packet
;;      CX loaded with the length of the packet and AX loaded with the
;;      type of the packet.  The code should
;;      execute ETH_R_RETURN when it is through.
;;
ETH_R_READ MACRO name, type, code_label
    local jmp_entry
    .errb <code_label>

jmp_entry = eth_&name&_data.eth_type_tab+2*((type / 256) xor (type mod 256))

    mov word ptr jmp_entry, offset code_label
ENDM

;;******************************************************************************
;;   ETH_R_CONT_in_BX_CX_ES name, ok
;;       ETH_R_CONT determines if the packet returned by R_READ in BX:ES
;;       of length CX is continuous.  If it is it jumps to 'ok' otherwise
;;       it just returns
;;
ETH_R_CONT_in_BX_CX_ES_const_BX_CX_DX_BP_SI_DI_ES MACRO name, ok
    .errb <ok>

    IF_R_CONT_in_BX_CX_ES_const_BX_CX_DX_BP_SI_DI_ES %eth_&name&_interface, ok
ENDM

;;******************************************************************************
;; ETH_R_RETURN
;;      ETH_R_RETURN should be called at the end of the read code to signal
;;      that the read code is finished with the packet read in
;;
ETH_R_RETURN MACRO name
    .errb <name>

    jmp eth_&name&_continue
ENDM


;;******************************************************************************
;;   ETH_W_ACCESS_in_CX_out_DI_ES name, no_buffer
;;       ETH_W_ACCESS returns a pointer to an output buffer for a (network)
;;       packet.  The pointer is returned in DI:ES.  If the output buffer is
;;       busy, this routine jump to 'no_buffer'.   The buffer return will
;;       be at least min(CX, 1500) bytes long
;;
ETH_W_ACCESS_in_CX_out_DI_ES_const_BX_CX_BP MACRO name, no_buffer
    .errb <no_buffer>

    add CX, size ether
    IF_W_ACCESS_in_CX_out_DI_ES_const_BX_CX_BP  %eth_&name&_interface, no_buffer
    sub CX, size ether
    add DI, size ether             ;; make it point to the Data part
ENDM


;;******************************************************************************
;;   ETH_W_WRITE_in_AX_CX_SI_DI_ES name, type
;;       ETH_W_WRITE actually signals the link layer to write a packet to the
;;       network.  The packet is assumed to be in the buffer returned by
;;       ETH_W_ACCESS.  CX is the length of the packet to send.   SI:DS holds
;;       is a pointer to the hardware destination address.  AX is the
;;       type code of the ethernet packet to send.
;;       DI:ES MUST point be the pointer returned by W_ACCESS_out_DI_ES
;;
ETH_W_WRITE_in_AX_CX_SI_DI_ES_const_BX_BP_ES MACRO name
    local size_ok
    .errb <name>

    add CX, size ether
    cmp CX, 64
    jae size_ok
        mov CX, 64
    size_ok:
    sub DI, size ether
    movsw
    movsw
    movsw

    mov SI, offset eth_&name&_address
    movsw
    movsw
    movsw

    stosw
    IF_W_WRITE_in_CX_const_BX_BP_ES %eth_&name&_interface
ENDM



;;******************************************************************************
;;   ETH_IS_BROADCAST_in_BX_ES name
;;      ETH_IS_BROADCAST_in_BX_ES determines if the packet pointed to
;;      by BX:ES is a broadcast and sets the zero flag if it is NOT a
;;      broadcast
;;
ETH_IS_BROADCAST_in_BX_ES_const_AX_BX_CX_DX_BP_DI_ES MACRO name
    .errb <name>

    mov SI, BX
    sub SI, size ether
    test byte ptr ES:[SI], 80H
ENDM


;;******************************************************************************
;;   ETH_COPY_in_CX_SI_DI_ES_out_SI_DI interface
;;   ETH_COPY_in_CX_SI_DI_ES copies a packet from the input buffer (pointed
;;      to by SI and the segement register given in IF_DECLARE) to an output
;;      buffer (pointed to by DI and dest_reg) of length CX.   It assumes the
;;      output buffer is contiguous.  (and the caller shouldn't care if the
;;      input buffer is contiguous)  COPY updates the pointers SI and DI
;;      to the end of the packet, and COPY could be called again if CX is not
;;      the total packet length (Note that CX MUST be even if you care about
;;      SI, and DI being updated properly)
;;
ETH_COPY_in_CX_SI_DI_ES_out_SI_DI_const_BX_BP_ES MACRO name
    .errb <name>
    IF_COPY_in_CX_SI_DI_ES_out_SI_DI_const_BX_BP_ES %eth_&name&_interface
ENDM


;;******************************************************************************
;;   ETH_TASK is the read task that reads the next packet from the interface
;;   and dispatches it to the next higher protocol layer
;;
ETH_TASK MACRO name
    local done
    .errb <name>

    IF_R_ACCESS_out_BX_CX_ES %eth_&name&_interface, done
    mov AX, word ptr ES:[BX+ether_type]
    add BX, size ether
    sub CX, size ether

    xor DX, DX                              ;; compute hash function
    mov DL, AH
    xor DL, AL
    shl DX, 1
    mov SI, DX                          ;;assume perfect hash function
    jmp [SI+eth_&name&_data.eth_type_tab]

    eth_&name&_continue:
        IF_R_FREE_const_BX_CX_BP_SI_DI_ES %eth_&name&_interface

    done:
    TASK_RETURN %eth_&name&_task
ENDM