124 lines
3.5 KiB
Plaintext
124 lines
3.5 KiB
Plaintext
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\ Denial of service protection.
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\ TODO: Use hash table instead?
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require util.4th
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[UNDEFINED] MAX_CONNECTIONS [IF] 32 constant MAX_CONNECTIONS [THEN]
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10 constant DOS_UPDATE_INTERVAL
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1024 constant DOS_BYTES_PER_INTERVAL
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10 constant DOS_LINES_PER_INTERVAL
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3 constant DOS_MAX_CONNECTIONS
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MAX_CONNECTIONS constant DOS_MAX_MAPPINGS
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\ TODO: is 0 a valid circuit id?
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\ TODO: if not, then we could use the circuit id instead of dos.set
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0
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cell +field dos.set
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cell +field dos.circuit-id
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cell +field dos.handled
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cell +field dos.connections
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cell +field dos.total-bytes
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cell +field dos.total-lines
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cell +field dos.bytes
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cell +field dos.lines
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constant /DOS
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/DOS DOS_MAX_MAPPINGS * constant DOS_ARRAY_SIZE
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create dos DOS_ARRAY_SIZE alloterase
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\ Lookup table: connection index -> dos stats
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create doslt DOS_MAX_MAPPINGS cells alloterase
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: (translate) ( index-n -- dos-addr )
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/DOS * dos + ;
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: (init-dos) ( free-addr circuit-id-n -- dos-addr )
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over dos.circuit-id !
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true over dos.set ! ;
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: (find) ( circuit-id-n -- dos-addr )
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0 swap dos DOS_ARRAY_SIZE + dos DO ( -- free-addr circuit-id-n )
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I dos.set @ IF
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dup I dos.circuit-id @ = IF
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2drop I UNLOOP EXIT
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THEN
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ELSE
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over 0= IF
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nip I swap
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THEN
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THEN
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/DOS +LOOP
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(init-dos) ;
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: (lttranslate) ( connection-index-n -- lookup-addr )
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cells doslt + ;
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: (lookup) ( connection-index-n -- dos-addr )
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(lttranslate) @ ;
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: (mod-connections) ( n dos-addr -- ) dos.connections +! ;
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: (inc-connections) ( dos-addr -- ) 1 swap (mod-connections) ;
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: (dec-connections) ( dos-addr -- ) -1 swap (mod-connections) ;
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: dos-add-connection ( circuit-id-n connection-index-n -- )
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(lttranslate) dup @ 0= IF
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swap (find) tuck (inc-connections) !
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ELSE
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2drop EXIT
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THEN ;
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: dos-remove-connection ( connection-index-n -- )
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\ erase if last connection
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(lttranslate) dup 0<> IF
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dup @ >r 0 swap ! r>
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dup (dec-connections)
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dup dos.connections @ 0= IF
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/DOS erase
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ELSE
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drop
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THEN
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ELSE
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drop
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THEN ;
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: dos-add-bytes ( bytes-n connection-index-n -- )
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(lookup) dos.bytes +! ;
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: dos-add-lines ( lines-n connection-index-n -- )
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(lookup) dos.lines +! ;
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: (update) ( dos-addr -- )
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dup dos.bytes @ over dos.total-bytes +!
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dup dos.lines @ over dos.total-lines +!
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0 over dos.bytes !
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0 over dos.lines !
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drop ;
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: dos-update ( -- )
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\ add time interval bytes and lines to total and set to 0
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dos DOS_ARRAY_SIZE + dos DO
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I dos.set @ IF
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I (update)
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THEN
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/DOS +LOOP ;
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: (check-bytes) ( dos-addr -- flag ) dos.bytes @ DOS_BYTES_PER_INTERVAL > ;
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: (check-lines) ( dos-addr -- flag ) dos.lines @ DOS_LINES_PER_INTERVAL > ;
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: (check-connections) ( dos-addr -- flag ) dos.connections @ DOS_MAX_CONNECTIONS > ;
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: dos-handled! ( flag connection-index-n -- )
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(lttranslate) @ dos.handled ! ;
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: dos-handled? ( connection-index-n -- flag )
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(lttranslate) @ dos.handled @ ;
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: dos? ( connection-index-n -- flag )
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(lttranslate) @
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dup (check-bytes) over (check-lines)
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rot (check-connections) or or ;
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: (.dos-info) ( dos-addr -- )
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dup ." CircuitID: " dos.circuit-id @ . cr
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dup ." Connections: " dos.connections @ . cr
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dup ." Total bytes: " dos.total-bytes @ . cr
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dup ." Total lines: " dos.total-lines @ . cr
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dup ." Bytes: " dos.bytes @ . cr
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dup ." Lines: " dos.lines @ . cr
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drop ;
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: .dos-info ( connection-index-u -- )
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(lttranslate) @ (.dos-info) ;
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: .dos ( -- )
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dos DOS_ARRAY_SIZE + dos DO
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I dos.set @ IF
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cr I (.dos-info)
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THEN
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/DOS +LOOP ;
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