Cjdnsplice - Tools for manipulating and splicing cjdns switch labels.

Fields

SCHEME_358

The encoding scheme consisting of 3, 5 or 8 bit data spaces, this encoding scheme is special because it encodes strangely (a bug) and thus conversion from one form to another is non-standard.

Functions

splice(label1, label2, ...)

This function takes one or more labels and splices them to create a resulting label. If you have a peer at 0000.0000.0000.0013 and he has a peer at 0000.0000.0000.0015 which you want to reach, you can splice a label for reaching him using splice("0000.0000.0000.0015", "0000.0000.0000.0013"). Remember that the arguments should be read right to left, the first hop is the furthest to the right in the splice function. If the result of the splicing is too long to fit in a label (60 bits) then it will return ffff.ffff.ffff.ffff.

See: LabelSplicer_splice()

Cjdnsplice.splice("0000.0000.0000.0015", "0000.0000.0000.0013") -> '0000.0000.0000.0153'

Splice only works to splice a route if the return route is the same size or smaller. If the return route is larger then the smaller director in the path must be re-encoded to be the same size as the return path director. buildLabel() will take care of this automatically.

printScheme(encodingScheme)

Prints the name of the encoding scheme if it is known, otherwise prints the JSON of the scheme.

Cjdnsplice.printScheme(Cjdnsplice.SCHEME_358) -> 'SCHEME_358'

isOneHop(label, encodingScheme)

Tests if a label contains only one hop, the first argument is the string representation of the label and the second argument is the encoding scheme used by the node which is at the beginning of the path given by the label.

See: EncodingScheme_isOneHop()

Cjdnsplice.isOneHop('0000.0000.0000.0013', Cjdnsplice.SCHEME_358) -> true
Cjdnsplice.isOneHop('0000.0000.0000.0015', Cjdnsplice.SCHEME_358) -> true
Cjdnsplice.isOneHop('0000.0000.0000.0153', Cjdnsplice.SCHEME_358) -> false

getEncodingForm(label, encodingScheme)

Get the number of the encoding form used for the first director of the label. Recall an encoding scheme is one or more encoding forms, this gets the number of that form or -1 if the label is not recognized as using the given scheme.

See: EncodingScheme_getFormNum()

Cjdnsplice.getEncodingForm('0000.0000.0000.0013', Cjdnsplice.SCHEME_358) -> 2
Cjdnsplice.getEncodingForm('0000.0000.0000.0402', Cjdnsplice.SCHEME_358) -> 1

reEncode(label, encodingScheme, desiredFormNum)

This will re-encode a label to the encoding form specified by desiredFormNumber. This form is the same as numbered by getEncodingForm(). This may throw an error if the encoding form cannot be detected, you pass an invalid desiredFormNum or if you try to re-encode the self route (0001). It will also throw an error if re-encoding a label will make it too long (more than 60 bits). If desiredFormNum is set to Cjdnsplice.FORM_CANNONICAL then it will re-encode the label into it's cannonical form, that is the smallest form which can hold that director.

See: EncodingScheme_convertLabel()

Cjdnsplice.reEncode("0000.0000.0000.0015", Cjdnsplice.SCHEME_358, 0) -> '0000.0000.0000.0404'
Cjdnsplice.reEncode("0000.0000.0000.0015", Cjdnsplice.SCHEME_358, 1) -> '0000.0000.0000.0086'
Cjdnsplice.reEncode("0000.0000.0000.0015", Cjdnsplice.SCHEME_358, 2) -> '0000.0000.0000.0015'
Cjdnsplice.reEncode("0000.0000.0000.0404", Cjdnsplice.SCHEME_358, Cjdnsplice.FORM_CANNONICAL) -> '0000.0000.0000.0015'

buildLabel(pathArray)

This will construct a label using an array representation of a path, if any label along the path needs to be re-encoded, it will be. Each element in the array represents a hop (node) in the path and they each contain labelP and/or labelN depending on whether there is a previous and/or next hop. labelP is necessary to know the width of the inverse path hop so that the label can be re-encoded if necessary.

Cjdnsplice.buildLabel([
    {"labelN":"0000.0000.0000.0015","encodingScheme":Cjdnsplice.SCHEME_358},
    {"labelN":"0000.0000.0000.008e","labelP":"0000.0000.0000.009e","encodingScheme":Cjdnsplice.SCHEME_358},
    {"labelN":"0000.0000.0000.00a2","labelP":"0000.0000.0000.0013","encodingScheme":Cjdnsplice.SCHEME_358},
    {"labelN":"0000.0000.0000.001d","labelP":"0000.0000.0000.001b","encodingScheme":Cjdnsplice.SCHEME_358},
    {"labelN":"0000.0000.0000.001b","labelP":"0000.0000.0000.00ee","encodingScheme":Cjdnsplice.SCHEME_358},
    {"labelN":"0000.0000.0000.001b","labelP":"0000.0000.0000.0019","encodingScheme":Cjdnsplice.SCHEME_358},
    {"labelP":"0000.0000.0000.0013","encodingScheme":Cjdnsplice.SCHEME_358}
]) -> { label: '0000.0003.64b5.10e5',
  path:
   [ '0000.0000.0000.0015',
     '0000.0000.0000.008e',
     '0000.0000.0000.00a2',
     '0000.0000.0000.001d',
     '0000.0000.0000.0092',
     '0000.0000.0000.001b' ] }

This function results in an Object containing 2 elements, "label" and "path". Label is the final label for this path while "path" is the hops to get there. Notice in the "path" element, the second to last hop hash been changed from 001b to 0092, this is a re-encoding to ensure that the label remains the right length as the reverse path for this hop is 00ee which is longer than 001b.

routesThrough(destination:string, midPath:string): boolean

This will return true if the node at the end of the route given by midPath is a hop along the path given by destination.

See LabelSplicer_routesThrough()

> Cjdnsplice.routesThrough("0000.001b.0535.10e5", "0000.0000.0000.0015")
true
> Cjdnsplice.routesThrough("0000.001b.0535.10e5", "0000.0000.0000.0013")
false

unsplice(destination:string, midPath:string): string

This will output a value which if passed to splice with the input midPath, would yield the input destination. If routesThrough(destination, midPath) would return false, this throws an error.

See LabelSplicer_unsplice()

> Cjdnsplice.splice("0000.0000.0000.0015", "0000.0000.0000.0013")
'0000.0000.0000.0153'
> Cjdnsplice.unsplice("0000.0000.0000.0153", "0000.0000.0000.0013")
'0000.0000.0000.0015'