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

Text File | 1991-02-19 | 24.0 KB | 728 lines

;;*************************************************************************
;;                         rip.inc       rip.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.
;;
;;*****************************************************************************
;;
;; rip.inc provides a ROUTE interface for th rip protocol.  In particular
;; it provides the following functions
;;
;; Routines provided by this module
;;
;;   RIP_DECLARE name, ip_net, timer, udp, udp_sock
;;   RIP_DEFINE name
;;   ROUTE_ADD_in_CX_SI_DI_ES_const_DI_ES name
;;   ROUTE_FIND_in_AX_BX_CX_out_AX_DL_const_BP_ES name, forme, fail
;;
;;*****************************************************************************

;;*****************************************************************************
;; definition of RIP packet structure

RIP_PORT                = 208h
SWAPPED_RIP_PORT        = 802h

RIP_REPLY               = 2         ;; sending out RIP packets
IP_FAMILY               = 2
SWAPPED_IP_FAMILY       = 200h

rip_head    STRUC
    rip_command         DB RIP_REPLY
    rip_version         DB 1
    rip_zero1           DW 0
rip_head    ENDS

rip_route   STRUC
    rip_family          DW SWAPPED_IP_FAMILY
    rip_zero2           DW 0
    rip_address         DD 0
    rip_zero3           DD 0
    rip_zero4           DD 0
    rip_metric          DD 8
rip_route   ENDS

;;*****************************************************************************
;; internal Routing table definitions

rip_entry  STRUC
   re_next      DW ?          ; this MUST be the first field
   re_prev      DW ?
   re_net       DD ?
   re_gateway   DW ?
   re_interface DB ?        ; interface MUST come directly before metric
   re_metric    DB ?
   re_flags     DB ?
   re_timer     DB ?
re_beautify     DW ?
rip_entry  ENDS

rip_table_size = 300
rip_data  STRUC
    rip_hash      DW 256 dup (0)
    rip_table     rip_entry rip_table_size dup (<>)
    rip_table_ptr DW ?                    ;; end of the routeing table
    rip_pack_ctr  DW ?
    rip_pack_ptr  DW ?
    rip_pack_out  DW ?
    rip_if_net    DD ?
    rip_if_last   DD ?
rip_data  ENDS
rip_table_end  = (rip_table+(rip_table_size*(size rip_entry)))

;; Routing Flags
ROUTE_SILENT =    (1 shl 0)      ; Do not broadcast via RIP
ROUTE_TRANS  =    (1 shl 1)      ; Transiant, can be changed by RIP

ROUTE_VALID  =    (1 shl 7)      ; a valid table entry


;;******************************************************************************
;;  RIP_DECLARE name, ip_net, timer, udp
;;       RIP_DECLARE delcares a new routing object called 'name'.
;;       'ip_net' is the IP_NET that the router is associated with,
;;       'timer' is a timer object, and 'udp' is the name of
;;       a UDP object (to get RIP packets from)
;;
RIP_DECLARE   MACRO  name, ip_net, timer, udp
    .errb <udp>

    .DATA
    rip_&name&_ip_net = ip_net
    rip_&name&_timer = timer
    rip_&name&_udp = udp
    rip_&name&_udp_sock = (name*100+1)
    rip_&name&_dls = ip_&ip_net&_dls
    global rip_&name&_data:rip_data

    .CODE
    global rip_&name&_read_code:near
    global rip_&name&_timer_code:near
    global rip_&name&_real_define:near
    global rip_&name&_send_dls:near

    UDP_SOCK_DECLARE %rip_&name&_udp_sock, %rip_&name&_udp, RIP_PORT
ENDM


;;******************************************************************************
;;   RIP_DEFINE   name
;;       RIP_DEFINE sets aside the memory and acutally does the
;;       initialization for the routeing objects 'name'
;;
RIP_DEFINE        MACRO   name
    call rip_&name&_real_define
ENDM

RIP_REAL_DEFINE   MACRO   name
    local around, listen_code
    .errb <name>

    .DATA
rip_&name&_data   rip_data  <>

    .CODE
    jmp around          ;; declare code objects
        rip_&name&_timer_code:
            RIP_TASK name
            TIMER_RETURN %rip_&name&_timer
                ;; this does NOT fall through

        rip_&name&_send_dls:
            RIP_SEND_DLS name
            ret

        rip_&name&_read_code:
            mov DI, BX
                ;; this is a violation of layering, but what can I do
            IP_R_HEADER_in_ES_out_SI_const_BX_CX_DX_BP_DI_ES %rip_&name&_ip_net
            add SI, ip_src
            xchg SI, DI
            RIP_PROCESS_PACKET_in_CX_SI_DI_ES name
            RET
                ;; this does NOT fall through

        listen_code:
                ;; because of circular dependance (RIP, a low level
                ;; protocol depending on UDP a high level protocol)
                ;; we have to defer the definition of this socket
            UDP_SOCK_DEFINE %rip_&name&_udp_sock, rip_&name&_read_code
            TIMER_RETURN %rip_&name&_timer
                ;; this does NOT fall through
    around:

rip_&name&_real_define:
    mov AX, DS              ; NULL all data
    mov ES, AX
    xor AX, AX
    mov CX, size rip_data
    mov DI, offset rip_&name&_data
    rep
    stosb

    mov rip_&name&_data.rip_table_ptr, offset rip_&name&_data.rip_table-(size rip_entry)

        ;; start RIP listening for packets
    mov AX, 18*0
    TIMER_MARK_in_AX_const_CX_BP_ES %rip_&name&_timer, listen_code

        ;; set the expire task to go off
    mov AX, 18*0
    TIMER_MARK_in_AX_const_CX_BP_ES %rip_&name&_timer, rip_&name&_timer_code

    RET
ENDM


;;******************************************************************************
;;   ROUTE_ADD_in_CX_SI_DI_ES name
;;      ROUTE_ADD adds the route to described by network pointed to by SI:ES,
;;      the gateway pointed to by DI:ES and the metric held in CL and flags
;;      (See flag defs above) held in CH, Note for directly connected networks
;;      (CL = 0) the 'gateway' (DI:ES) must point to the IP address of this host
;;
ROUTE_ADD_in_CX_SI_DI_ES_const_DI_ES MACRO name
   local done, look_for_empty, found_empty, no_wrap, found, new_route
   local add_new_gateway, not_bigger, delete_route, delete_trigger

    mov AX, ES:[SI]
    mov BX, ES:[SI+2]
    mov BP, DI                      ; save DI
    IP_COMPUTE_NET_in_AX_BX_out_AX_BX_const_CX_DX_BP_SI_DI_ES rip_&name&_dls
    RIP_GET_ENTRY_in_AX_BX_out_SI_DI_const_AX_BX_CX_BP name, found
        cmp CL, 16
        jae done
        mov SI, word ptr rip_&name&_data.rip_table_ptr
        look_for_empty:
            add SI, size rip_entry
            cmp SI, offset rip_&name&_data.rip_table_end
            jb no_wrap
                mov SI, offset rip_&name&_data.rip_table
            no_wrap:
            test byte ptr [SI.re_flags], ROUTE_VALID
            jz found_empty

            cmp SI, word ptr rip_&name&_data.rip_table_ptr
            jnz look_for_empty
            LOG_PRINT %mylog, L_ROUTE, L_ERR, <Routing table overflow>
            jmp done
        found_empty:
        cmp SI, word ptr rip_&name&_data.rip_table_ptr
        jbe not_bigger
            mov word ptr rip_&name&_data.rip_table_ptr, SI
        not_bigger:
        mov [SI.re_prev], DI            ;; link this in last in the list
        mov [DI.re_next], SI

        mov [SI+re_next], 0             ;; fill in next
        mov word ptr [SI+re_net], AX
        mov word ptr [SI+re_net+2], BX
        or CH, ROUTE_VALID              ;; fill in flags
        mov byte ptr [SI+re_flags], CH
        jmp  add_new_gateway

    delete_trigger:
    delete_route:
        LOG_PRINT_INET_in_AX_BX %mylog, L_ROUTE, L_INFO, <Rip from bogus host>
        RIP_DELETE_in_SI_const_BX_CX_DX_SI_BP name
        jmp done

    found:
        test [SI+re_flags], ROUTE_TRANS   ;; cant change a permanent route
        jz done

        mov DI, BP                          ;; restore DI
        mov DX, ES:[DI+2]
        cmp DX, [SI+re_gateway]
        jnz new_route
            mov byte ptr [SI+re_metric], CL
            cmp CL, 16
            jae done
                mov byte ptr [SI+re_timer], 3
                jmp done
        new_route:
        cmp CL, [SI+re_metric]
        jae done                            ;; old metric less, we are done

    add_new_gateway:
    mov DI, BP                              ;; restore DI
    mov byte ptr [SI+re_timer], 3
    mov byte ptr [SI+re_metric], CL
    mov AX, ES:[DI]
    mov BX, ES:[DI+2]
    mov word ptr [SI+re_gateway], BX
    RIP_FIND_IF_in_AX_BX_out_CL_const_AX_BX_SI_DI %rip_&name&_dls, delete_route
    mov byte ptr [SI+re_interface], CL

    LOG_PRINT %mylog, L_ROUTE, L_INFO, <Adding the Following Route>
    RIP_LOG_ROUTE_in_SI_const_all name, L_INFO
    done:
    mov DI, BP                          ;; restore DI
ENDM


;;*****************************************************************************
;;   ROUTE_FIND_in_AX_BX_CX_out_AX_DL name, forme, fail
;;      ROUTE_FIND takes the network number in the AX:BX pair and the
;;      host part in CX of a packet address and does one of three things
;;      if it is for this host it jumps to 'forme'.  If it could find no
;;      route it jumps to 'fail'. otherwise outputs the DL interface
;;      in DL and the gatway host part in AX of where to send it to.
;;
ROUTE_FIND_in_AX_BX_CX_out_AX_DL_const_BP_ES MACRO name, forme, fail
    local found, done, not_direct

    RIP_GET_ENTRY_in_AX_BX_out_SI_DI_const_AX_BX_CX_BP name, found
    xor AX, AX                          ; check the default route
    xor BX, BX
    RIP_GET_ENTRY_in_AX_BX_out_SI_DI_const_AX_BX_CX_BP name, found
    jmp fail

    found:
    mov DX, word ptr [SI+re_interface]  ; load DL=interface DH=metric
    mov AX, [SI+re_gateway]
    or DH, DH
    jnz not_direct
        cmp AX, CX
        jz forme                ;; the re_gateway holds my IP address
        mov AX, CX              ;; for direct routes
    not_direct:
    done:
ENDM


;;**************************************************************************
;; RIP_TASK is the code that goes off in 30 seconds.  Basicly all it does
;; is call RIP_EXPIRE and then resubmit a timer request so it will go off
;; 30 seconds in the future
;;
RIP_TASK MACRO name
    local timer_code, rip_loop, packets_sent

    timer_code:
        RIP_EXPIRE_const_BX_CX_DX_BP name

        call rip_&name&_send_dls

        mov AX, 18*30               ;; resubmit the task 30 seconds from now
        TIMER_MARK_in_AX_const_CX_BP_ES %rip_&name&_timer, timer_code
ENDM


;;**************************************************************************
;; RIP_SEND_DLS sends out a RIP update.
;;
RIP_SEND_DLS MACRO name

    IRP idx, <1,2,3,4,5,6,7,8>
    if idx le rip_&name&_dls
        RIP_SEND_DL name, idx
    endif
    endm
ENDM

;;**************************************************************************
;; RIP_SEND_DL generates all the RIP packets for the data link interface 'mydl'
;;
RIP_SEND_DL MACRO name, mydl
    local done, pack_loop
    .errb <mydl>

    mov AX, word ptr dl_ip_&mydl&_flags
    test word ptr dl_ip_&mydl&_flags, ROUTE_DL_SILENT   ;; skip silent ifs
    jnz done
    mov AX, word ptr dl_ip_&mydl&_ip
    mov BX, word ptr dl_ip_&mydl&_ip+2
    IP_COMP_NET_in_AX_BX_out_AX_BX_const_CX_DX_BP_SI_DI_ES rip_&name&_dls
    mov word ptr rip_&name&_data.rip_if_net, AX
    mov word ptr rip_&name&_data.rip_if_net+2, BX

    RIP_INIT_ENTRY_out_SI_const_AX_BX_CX_DX_BP_DI name
    mov rip_&name&_data.rip_pack_out, SI
    pack_loop:
        mov CX, 512                 ;; maximum RIP packet size
        mov DX, RIP_PORT
        mov AX, word ptr dl_ip_&mydl&_broad
        mov BX, word ptr dl_ip_&mydl&_broad+2

        UDP_SOCK_W_ACCESS_in_AX_BX_CX_DX_out_AX_DI_ES %rip_&name&_udp_sock
        cmp AX, 0
        jnz done

        mov DL, mydl
        mov DH, byte ptr dl_ip_&mydl&_metric
        mov SI, rip_&name&_data.rip_pack_out
        RIP_MAKE_PACKET_in_DX_SI_DI_out_CX_SI_const_BP name, rip_&name&_data.rip_if_net, done
        mov rip_&name&_data.rip_pack_out, SI

        UDP_SOCK_W_WRITE_in_CX %rip_&name&_udp_sock
    jmp pack_loop
    done:
ENDM


;;**************************************************************************
;; RIP_DELETE_in_SI_const_BX_CX_DX_SI_BP deletes the entry pointed by by SI
;;
RIP_DELETE_in_SI_const_BX_CX_DX_SI_BP MACRO name
    local end_of_list

    mov byte ptr [SI+re_flags], 0       ;; make the route invalid
    mov DI, [SI+re_prev]
    mov AX, [SI+re_next]
    mov [DI.re_next], AX
    or AX, AX
    jz end_of_list
        xchg AX, DI
        mov [DI+re_prev], AX
    end_of_list:
ENDM


;;**************************************************************************
;; RIP_EXPIRE should be called every 30 seconds.  This routine decrements
;; the timer entries on the routes and expires the routes after 90 seconds.
;;
RIP_EXPIRE_const_BX_CX_DX_BP MACRO name
    local expire_loop, done, delete_route
    .errb <name>

    RIP_INIT_ENTRY_out_SI_const_AX_BX_CX_DX_BP_DI name
    expire_loop:
        RIP_NEXT_ENTRY_in_SI_out_SI_const_AX_BX_CX_DX_BP_DI name, done
        test [SI+re_flags], ROUTE_TRANS      ;; don't expire permenent routes
        jz expire_loop

        sub [SI+re_timer], 1                   ;; decrement the timer
        jg expire_loop
        jz delete_route
                ;; check to see if we should purge it from the table
            cmp [SI+re_timer], -3
            jg expire_loop
                RIP_DELETE_in_SI_const_BX_CX_DX_SI_BP name
                jmp expire_loop
        delete_route:
                ;; delete the route
            mov [SI+re_metric], 16
            LOG_PRINT %mylog, L_ROUTE, L_INFO, <Route expired.  Deleting route>
            RIP_LOG_ROUTE_in_SI_const_all name, L_INFO
            jmp expire_loop
    done:
ENDM


;;**************************************************************************
;; RIP_PROCESS_PACKET processes the packet in ES:SI.  The IP address of
;; the gateway that sent the packet is pointed to by ES:DI.  CX holds
;; the length of the RIP part of the packet

RIP_PROCESS_PACKET_in_CX_SI_DI_ES MACRO name
    local process_loop, done, next

    mov AX, word ptr ES:[DI]
    mov BX, word ptr ES:[DI+2]
    RIP_SHOULD_LISTEN_in_AX_BX_const_CX_SI_DI_ES name, done
    cmp byte ptr ES:[SI+rip_command], RIP_REPLY
    jnz done
    cmp byte ptr ES:[SI+rip_version], 1
    jnz done
        add SI, 4
        sub CX, 4
        process_loop:
            sub CX, 20
            jb done

            cmp word ptr ES:[SI+rip_family], SWAPPED_IP_FAMILY
            jnz next
            cmp word ptr ES:[SI+rip_zero3], 0       ;; not complete checks
            jnz next
            cmp word ptr ES:[SI+rip_zero4], 0
            jnz next

            mov word ptr rip_&name&_data.rip_pack_ctr, CX
            mov word ptr rip_&name&_data.rip_pack_ptr, SI
            mov CL, byte ptr ES:[SI+rip_metric+3]
            mov CH, ROUTE_TRANS
            add SI, rip_address
            ROUTE_ADD_in_CX_SI_DI_ES_const_DI_ES name
            mov CX, word ptr rip_&name&_data.rip_pack_ctr
            mov SI, word ptr rip_&name&_data.rip_pack_ptr

            next:
                add SI, 20
        jmp process_loop
    done:
ENDM


;;**************************************************************************
;; RIP_SHOULD_LISTEN determines if we should listen to a RIP packet from
;; the gateway AX:BX.  If the packet should be dropped this macro jumps
;; to 'drop'
;;
RIP_SHOULD_LISTEN_in_AX_BX_const_CX_SI_DI_ES MACRO name, drop
    .errb <drop>

    IRP idx, <1,2,3,4,5,6,7,8>
    local notme
    if idx le rip_&name&_dls
            RIP_CHECK_IF_in_AX_BX_const_AX_BX_CX_SI_DI_ES idx, notme
            RIP_CHECK_FLAGS idx, ROUTE_DL_DEAF
            jz done
            jmp drop
        notme:
    endif
    endm
    jmp drop
    done:
ENDM

RIP_CHECK_FLAGS MACRO dl, mask
    test word ptr dl_ip_&dl&_flags, mask
ENDM


;;**************************************************************************
;; RIP_MAKE_PACKET generates a RIP packet in DI:ES for the interface in DL
;; by calling accessing the routing table by means of RIP_NEXT_ENTRY.
;; Thus it assumes SI has been initialized with RIP_INIT_ENTRY or is
;; a continuation of a RIP_NEXT_ENTRY..  CX is set to the length of the
;; packet.  It jumps to 'dont_send' when there is not data to send out, so
;; that the packet should not be sent.  DH contains the interface metric
;; for the interface.  'if_net' is a pointer to the network part (not assuming
;; subnets, that is based strictly on the Class of the address).  This is
;; used to implement the subnet hiding

RIP_MAKE_PACKET_in_DX_SI_DI_out_CX_SI_const_BP MACRO name, if_net, dont_send
    local route_loop, packet_full, metric_ok
    local send_full_route, not_same_subnet, not_last, send_metric
    .errb <dont_send>

        ;; make up header
    mov AL, RIP_REPLY               ;; this is a reply packet
    stosb
    mov AL, 1                       ;; version 1
    stosb
    xor AX, AX                      ;; must be 0
    stosw
    dec AX                          ;; AX now = -1
    mov word ptr rip_&name&_data.rip_if_last, AX
    mov word ptr rip_&name&_data.rip_if_last+2, AX
    mov CX, 4
    route_loop:
        RIP_NEXT_ENTRY_in_SI_out_SI_const_AX_BX_CX_DX_BP_DI name, packet_full
        test [SI+re_flags], ROUTE_SILENT
        jnz route_loop

        cmp DL, [SI+re_interface]           ;; split horizon
        jz route_loop

            ;; this code implements the hiding of subnet info outside
            ;; the subnet
        mov AX, word ptr [SI+re_net]         ;; the destination network
        mov BX, word ptr [SI+re_net+2]
        IP_COMP_NET_in_AX_BX_out_AX_BX_const_CX_DX_BP_SI_DI_ES rip_&name&_dls
        cmp AX, word ptr if_net
        jnz not_same_subnet
        cmp BX, word ptr if_net+2
        jz send_full_route
            not_same_subnet:
            cmp AX, word ptr rip_&name&_data.rip_if_last
            jnz not_last
            cmp BX, word ptr rip_&name&_data.rip_if_last+2
            jz route_loop
            not_last:
                mov word ptr rip_&name&_data.rip_if_last, AX
                mov word ptr rip_&name&_data.rip_if_last+2, BX

                mov AX, SWAPPED_IP_FAMILY            ;; Address family
                stosw
                xor AX, AX                           ;; two bytes of zero
                stosw
                mov AX, word ptr rip_&name&_data.rip_if_last
                stosw
                mov AX, word ptr rip_&name&_data.rip_if_last+2
                stosw
                jmp send_metric

        send_full_route:
        mov AX, SWAPPED_IP_FAMILY            ;; Address family
        stosw
        xor AX, AX                           ;; two bytes of zero
        stosw
        mov AX, word ptr [SI+re_net]         ;; the destination network
        stosw
        mov AX, word ptr [SI+re_net+2]
        stosw

        send_metric:
        xor AX, AX                           ;; 8 zero bytes
        stosw
        stosw
        stosw
        stosw
        stosw                               ;; 4 bytes of metric
        mov AH, [SI+re_metric]
        add AH, DH                          ;; add in the interface metric
        cmp AH, 16
        jbe metric_ok
            mov AH, 16
        metric_ok:
        stosw

        add CX, 20
        cmp CX, 512-20                  ;; is there space for another entry
        ja packet_full
    jmp route_loop

    packet_full:
    cmp CX, 4
    jz dont_send
ENDM



;;**************************************************************************
;; RIP_INIT_ENTRY initilizes SI so that RIP_NEXT_ENTRY works.  When
;; RIP_NEXT_ENTRY is called, SI will point to the first entry of the
;; routing table.  This may seem a bit bizarre that RIP_NEXT_ENTRY MUST
;; be called immediately after RIP_INIT_ENTRY, but it actually makes
;; loops easier to construct.

RIP_INIT_ENTRY_out_SI_const_AX_BX_CX_DX_BP_DI MACRO name
    .errb <name>

    mov SI, offset (rip_&name&_data.rip_table - (size rip_entry))
ENDM


;;**************************************************************************
;; RIP_NEXT_ENTRY gets the next entry in the table and returns it in
;; SI.  NOTE: SI must be unchanged from the last RIP_INIT_ENTRY or
;; RIP_NEXT_ENTRY for this function to work.  It jumps to 'done' if
;; there are no more entries.
;;
RIP_NEXT_ENTRY_in_SI_out_SI_const_AX_BX_CX_DX_BP_DI MACRO name, done
    local search_loop
    .errb <done>

    search_loop:
        add SI, size rip_entry
        cmp SI, word ptr rip_&name&_data.rip_table_ptr
        ja done
        test [SI+re_flags], ROUTE_VALID
    jz search_loop
ENDM


;;**************************************************************************
;; RIP_GET_ENTRY gets the table entry for the network in the AX:BX
;; pair and returns a pointer to it in SI. DI returns the pointer to
;; the previous entry in the list (useful for insertions and deletions)
;; It jumps to 'found' if the network entry could is found.  If it is
;; not found only DI is valid (SI will be 0)
;;
RIP_GET_ENTRY_in_AX_BX_out_SI_DI_const_AX_BX_CX_BP MACRO name, found
    local start, done, next, search_loop
    .errb <found>

    mov DL, AL
    add DL, AH
    add DL, BL
    add DL, BH                  ;; compute the hash function
    xor DH, DH
    mov SI, DX
    shl SI, 1
    add SI, offset rip_&name&_data.rip_hash

    jmp start
    search_loop:
        cmp AX, word ptr [SI+re_net]
        jnz next
        cmp BX, word ptr [SI+re_net+2]
        jnz next
        jmp found
    next:
    start:
        mov DI, SI
        mov SI, [SI+re_next]

        or SI, SI
        jnz search_loop
    ;; failure
ENDM


;;******************************************************************************
;; Find interface finds the interface for the network address in AX:BX
;; from the dl list 1, 2, ... 'dls' and puts it in CL.  It jumps to 'fail'
;; if the address is not on any of the interfaces in 'dls'.
;;
RIP_FIND_IF_in_AX_BX_out_CL_const_AX_BX_SI_DI MACRO dls, fail
    local done
    .errb <fail>

    xor CL, CL
    IRP idx, <1,2,3,4,5,6,7,8>
    local notme
    if idx le dls
            RIP_CHECK_IF_in_AX_BX_const_AX_BX_CX_SI_DI_ES idx, notme
            mov CL, idx
            jmp done
        notme:
    endif
    endm
    jmp fail
    done:
ENDM

;;*****************************************************************************
;; RIP_CHECK_IF_in_AX_BX checks if the ip address in AX:BX matches the network
;; associated with 'dl'.   If it does NOT it jumps to 'fail'
;;
RIP_CHECK_IF_in_AX_BX_const_AX_BX_CX_SI_DI_ES MACRO dl, fail
    cmp AX, word ptr dl_ip_&dl&_net
    jnz fail
    mov DX, BX
    and DX, word ptr dl_ip_&dl&_mask+2
    cmp DX, word ptr dl_ip_&dl&_net+2
    jnz fail
ENDM


;;*****************************************************************************
;; RIP_LOG_ROUTE_in_SI_const_ALL prints out the route entry pointed to by
;; SI:DS to the loging host
;;
RIP_LOG_ROUTE_in_SI_const_all MACRO name, severity
    push AX
    push BX

    mov AX, word ptr [SI+re_net]
    mov BX, word ptr [SI+re_net+2]
    LOG_PRINT_INET_in_AX_BX %mylog, L_ROUTE, severity, <    Routing to network >
    xor AX, AX
    mov AL, byte ptr [SI+re_interface]
    LOG_PRINT_REG_DEC  %mylog, L_ROUTE, severity, <    Through interface >, AX
    mov AX, word ptr [SI+re_gateway]
    xchg AH, AL
    LOG_PRINT_REG_HEX  %mylog, L_ROUTE, severity, <    To host with IP addr ending with >, AX
    xor AX, AX
    mov AL, byte ptr [SI+re_metric]
    LOG_PRINT_REG_DEC  %mylog, L_ROUTE, severity, <    Routing Metric >, AX

    pop BX
    pop AX
ENDM