PC Press: Internet/PC_PRESS.ISO/software/dos/misc/inar-100.exe/SRC/PCROUTE/PACKET.INC

Text File | 1995-05-21 | 12.3 KB | 391 lines

;;******************************************************************************
;;                         packet.inc      packet.inc
;;******************************************************************************
;;
;;  Copyright (C) 1989 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.
;;
;; Vance Morrison 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.
;;
;;******************************************************************************
;; packet.inc contains the interface driver for the the packet  driver
;; (a la FTP software, drivers and info available from sun.soe.clarson.edu)
;;
;; Note that this interface driver is VERY inefficient.  basically packets
;; are copyied once on read and once again on write.   Thus this driver will
;; be at best 1/3 the speed of a native driver.  Nevertheless, this speed
;; may be acceptable, (and besides it gets all those people who want 3Com
;; support off my back).   There are other inefficiencies as well (saving
;; and restoring registers, waiting for packets to be sent etc), but even
;; so it will be usefull for low performance applications.
;;
;; Note that this these routines do not use any extended or high performance
;; packet driver calls.  Only the basic calls are used
;;
;; The functions provided by this file are
;;
;;   PKT_DECLARE name, driver_int, driver_class, prom
;;   PKT_DEFINE name, fail
;;   PKT_IF_R_ACCESS_out_BX_CX_ES name, no_packet
;;   PKT_IF_R_CONT_in_BX_CX_ES_const_BX_CX_DX_BP_SI_DI_ES name, ok
;;   PKT_IF_R_FREE_const_BX_CX_BP_SI_DI_ES name
;;   PKT_IF_W_ACCESS_in_CX_out_DI_ES_const_BX_CX_BP name, no_buffer
;;   PKT_IF_W_WRITE_in_CX_const_BX_BP_ES name
;;   PKT_IF_SET_ADDRESS_in_SI_const_BX_CX_BP_DI_ES name
;;   PKT_IF_COPY_in_CX_SI_DI_ES_out_SI_DI_const_BX_BP_ES name
;;
;; Variables set by this module
;;
;;   pkt_&name&_declared                     ;; one if this interface exists
;;   if_&name&_address                       ;; the hardware address
;;   if_&name&_mtu                           ;; the maximum trans unit
;;
;;******************************************************************************

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

pkt_r_q_entry STRUC
    pkt_q_rstart    DW ?
    pkt_q_rend      DW ?
pkt_r_q_entry ENDS

pkt_data  STRUC
    pkt_bseg        DW ?
    pkt_bend        DW ?
    pkt_bstart      DW ?
pkt_data ENDS


;;******************************************************************************
;;   IF_DECLARE name, driver_int driver_class, promiscuous
;;       declares an interface object.  driver_int is the interupt number
;;   to use to access the packet driver (60H-80H).  driver_class is
;;   the packet driver class of the card (Ethernet = 1)
;;
PKT_DECLARE MACRO name, driver_int, driver_class, mtu_val, rbuff_len, promiscuous
    .errb <name>
    .errb <driver_int>

    .DATA
    pkt_&name&_declared     = 1
    pkt_&name&_drv_int   = driver_int
    pkt_&name&_drv_class = driver_class
    pkt_&name&_rbuff_len = rbuff_len

    pkt_&name&_rbuff   = name*100+1
    pkt_&name&_rqueue  = name*100+2

    pkt_&name&_promiscuous = 0
    ifnb <promiscuous>
        pkt_&name&_promiscuous = 0&promiscuous
    endif

    if_&name&_mtu = mtu_val
    global pkt_&name&_wbuffer:byte
    global pkt_&name&_data:pkt_data
    global if_&name&_address:word

    .CODE
    global pkt_&name&_data_seg:word
    global pkt_&name&_real_define:near
    BUFF_DECLARE %pkt_&name&_rbuff, rbuff_len, pkt_&name&_rbuffer
    QUEUE_DECLARE %pkt_&name&_rqueue, %((rbuff_len+127)/128), %(size pkt_r_q_entry)
ENDM


;;******************************************************************************
;;   IF_DEFINE name, fail
;;      sets asside memory an name object and initializes it.  This
;;      routine is a no-op if 'name' was not declared.  It jumps to 'fail'
;;      if there was an error in  setup.
;;
PKT_DEFINE MACRO name, fail
ifdef pkt_&name&_declared
    BUFF_DEFINE %pkt_&name&_rbuff
    QUEUE_DEFINE %pkt_&name&_rqueue
    call pkt_&name&_real_define
    or AX, AX
    jnz fail
endif
ENDM


PKT_REAL_DEFINE MACRO name
    local pkt_read_task, got_driver, got_address, size_check, no_room, done
    local set_prom, type_count, type_loop, type_done, pkt_handle
    .errb <name>

ifdef pkt_&name&_declared
    .DATA
    type_count         DW ?
    if pkt_&name&_promiscuous eq 1
        pkt_handle     DW ?
    endif
    if_&name&_address  DW 3 DUP (0)
    pkt_&name&_wbuffer DB 1536 dup (0)
    pkt_&name&_data    pkt_data      <>  ;; create storage needed

    .FARDATA? pkt_&name&_bseg
    pkt_&name&_rbuffer DB pkt_&name&_rbuff_len dup (?)

    .CODE
    ;;*****************************************************************
    pkt_&name&_real_define:
    mov word ptr CS:pkt_&name&_data_seg, DS
    mov AX, SEG pkt_&name&_rbuffer
    mov pkt_&name&_data.pkt_bseg, AX
    mov ES, AX
    mov DI, offset pkt_&name&_rbuffer
    mov CX, pkt_&name&_rbuff_len
    xor AL, AL
    rep
    stosb

    mov AX, word ptr eth_&name&_data.eth_read_cnt
    inc AX
    mov word ptr type_count, AX
    mov SI, offset eth_&name&_data.eth_read_jmp.eth_read_type

    type_loop:
    dec word ptr type_count
    jz type_done
    push SI             ;; save packet type pointer
    mov AH, 2           ;; access_type driver call
    mov AL, pkt_&name&_drv_class    ;; driver class
    mov DL, 0           ;; wildcard number
    mov BX, 0FFFFH      ;; wildcard Type
    mov CX, (size eth_read_type)  ;; length of packet type field
    mov DI, CS          ;; point to my packet receiver
    mov ES, DI
    mov DI, offset pkt_read_task
    stc
    PKT_CALL_DRIVER name
    jnc got_driver
        pop AX
        mov DL, DH
        xor DH, DH
        mov AX, DX
        ret
    got_driver:
    pop SI
    add SI, (size eth_jmp_entry)
    jmp type_loop

    type_done:
    if pkt_&name&_promiscuous eq 1
        mov word ptr pkt_handle, AX
    endif

    mov BX, AX
    mov AH, 6           ;; get ethernet address
    mov DX, DS
    mov ES, DX
    mov DI, offset if_&name&_address
    mov CX, 6           ;; length of address buffer
    stc
    PKT_CALL_DRIVER name
    jnc got_address
        mov DL, DH
        xor DH, DH
        mov AX, DX
        ret
    got_address:

    if pkt_&name&_promiscuous eq 1
        mov BX, word ptr pkt_handle
        mov AH, 20      ;; set recieve mode
        mov CX, 6       ;; to recieve all packets
        stc
        PKT_CALL_DRIVER name
        jnc set_prom
            mov DL, DH
            xor DH, DH
            mov AX, DX
            ret
        set_prom:
    endif

    xor AX, AX
    sti              ;; turn on interupts if they are not already on
    ret

    ;;*********************************************************************
    ;; 'interupt' routine
    pkt_&name&_data_seg: DW 0

    pkt_read_task:
    push DS
    segcs
    mov DS, word ptr pkt_&name&_data_seg
    or AX, AX
    jz size_check
        QUEUE_ENQUEUE_out_DI_const_BX_CX_DX_BP_SI_ES %pkt_&name&_rqueue, done
        mov AX, pkt_&name&_data.pkt_bstart
        mov [DI+pkt_q_rstart], AX
        mov AX, pkt_&name&_data.pkt_bend
        mov [DI+pkt_q_rend], AX
        done:
        pop DS
        retf
    size_check:
       BUFF_CHECK_in_CX_out_SI_DI_const_BX_CX_DX_BP_ES %pkt_&name&_rbuff,no_room
           BUFF_GET_in_DI_const_AX_BX_CX_DX_BP_SI_DI_ES %pkt_&name&_rbuff
           mov pkt_&name&_data.pkt_bstart, SI
           mov pkt_&name&_data.pkt_bend, DI
           mov DI, SI
           mov ES, pkt_&name&_data.pkt_bseg
           pop DS
           retf
        no_room:
           xor DI, DI
           mov ES, DI
           pop DS
           retf

endif
ENDM


;;******************************************************************************
;;   IF_R_ACCESS_out_BX_ES name, no_packet
;;       IF_R_ACCESS checks for the next packet to come from the the board
;;       associated with 'name' and returns a pointer to the begining of
;;       an ethernet packet in BX:ES.  CX holds the length of the packet
;;       R_ACCESS jumps to 'no_packet' if there are no packets waiting to
;;       be read in
;;
PKT_IF_R_ACCESS_out_BX_CX_ES MACRO name, no_packet
    .errb <no_packet>

    QUEUE_HEAD_out_SI_const_AX_BX_CX_DX_BP_DI_ES %pkt_&name&_rqueue, no_packet
    mov BX, [SI+pkt_q_rstart]
    mov CX, [SI+pkt_q_rend]
    sub CX, BX
    mov ES, pkt_&name&_data.pkt_bseg
ENDM


;;******************************************************************************
;;   IF_R_FREE_const_BX_CX_BP_SI_DI_ES  name
;;       After the client is through processing the packet returned by
;;       IF_R_ACCESS, IF_R_FREE must be called to inform 'name' that the
;;       memory that the packet was in can be reused for future packets.
;;
PKT_IF_R_FREE_const_BX_CX_BP_SI_DI_ES MACRO name
    local done
    .errb <name>

    cli
    QUEUE_HEAD_out_SI_const_AX_BX_CX_DX_BP_DI_ES %pkt_&name&_rqueue, done
    mov DI, [SI+pkt_q_rend]
    BUFF_FREE_in_DI_const_AX_BX_CX_DX_BP_SI_DI_ES %pkt_&name&_rbuff
    QUEUE_DEQUEUE_in_SI_const_AX_BX_CX_DX_BP_DI_ES %pkt_&name&_rqueue
    done:
    sti
ENDM


;;******************************************************************************
;;   PKT_IF_R_CONT_in_BX_CX_ES name, ok
;;       IF_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
;;
PKT_IF_R_CONT_in_BX_CX_ES_const_BX_CX_DX_BP_SI_DI_ES MACRO name, ok
    .errb <ok>

    jmp ok      ;; is it always continuous
ENDM


;;******************************************************************************
;;   IF_W_ACCESS_in_CX_out_DI_ES name, no_buffer
;;       IF_W_ACCESS returns a pointer to an output buffer for a packet.  The
;;       pointer is returned in DI:ES.  If the ouptut buffer is busy, this
;;       routine will jump to 'no_buffer'.  The output buffer  min(CX, 1536)
;;       bytes long
;;
PKT_IF_W_ACCESS_in_CX_out_DI_ES_const_BX_CX_BP MACRO name, no_buffer
    .errb <no_buffer>

   mov DI, offset pkt_&name&_wbuffer
   mov AX, DS
   mov ES, AX
ENDM


;;******************************************************************************
;;   IF_W_WRITE_in_CX name
;;       IF_W_WRITE actually signals the ethernet board to write a packet to
;;       the ethernet.  The packet is assumed to be in the buffer returned by
;;       IF_W_ACCESS. CX is the length of the packet to send.
;;
PKT_IF_W_WRITE_in_CX_const_BX_BP_ES MACRO name
    .errb <name>

    push BX
    push BP
    push ES

    mov AH, 4               ;; set_pkt command
    mov SI, offset pkt_&name&_wbuffer   ;; the packet to send
                            ;; DS is OK as it stands
                            ;; CX is also fine as is
    PKT_CALL_DRIVER name
    pop ES
    pop BP
    pop BX
ENDM


;;******************************************************************************
;;   IF_SET_ADDRESS_in_SI name
;;       IF_SET_ADDRESS_in_SI sets the hardware address to be the value
;;       pointed to by SI.  Note this function may be a no-op if the
;;       hardware address cannot be set (ETHERNET for example)
;;

PKT_IF_SET_ADDRESS_in_SI_const_BX_CX_BP_DI_ES MACRO name
    .err    ;; we don't support setting ethernet addresses (yet)
    ENDM


;;******************************************************************************
;;   IF_COPY_in_CX_SI_DI_ES_out_SI_DI name
;;      IF_COPY_in_CX_SI_DI_ES copys 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 ES) of length CX.   It assumes the
;;      output buffer is contiguous.  (and the caller shouln't care if the
;;      input buffer is contiguous)
;;
PKT_IF_COPY_in_CX_SI_DI_ES_out_SI_DI_const_BX_BP_ES MACRO name
    .errb <name>

    ;; since DS points to the data segment, we are ready to go!!
    inc CX
    shr CX,1
    rep movsw
ENDM

;;******************************************************************************
;; PKT_CALL_DRIVER calls the drivers, but it also makes sure that the
;; segment registers are preserved.

PKT_CALL_DRIVER MACRO name
    .errb <name>

    push DS
    push SS
    int pkt_&name&_drv_int
    pop SS
    pop DS
ENDM