ndn.app_support.light_versec package

ndn.app_support.light_versec.compile_lvs(lvs_text)

Compile a text Light VerSec file into a TLV encodable binary LVS model. The latter one can be used to create validators.

Parameters

lvs_text (str) – Light VerSec text file

Return type

LvsModel

Returns

LVS model

Raises

  • SemanticError – when the given text file has a semantic error

  • lark.UnexpectedInput – when the given text file has a syntax error

class ndn.app_support.light_versec.Checker(model, user_fns)

A checker uses a LVS model to match names and checks if a key name is allowed to sign a packet.

Variables

  • model – the LVS model used.

  • user_fns – user functions

check(pkt_name, key_name)

Check whether a packet can be signed by a specified key.

Parameters
Return type

bool

Returns

whether the key can sign the packet

static load(binary_model, user_fns)

Load a Light VerSec model from bytes.

Parameters

  • binary_model (BinaryStr) – the compiled LVS model in bytes

  • user_fns (dict[str, UserFn]) – user functions

match(name)

Iterate all matches of a given name.

Parameters

name (NonStrictName) – input NDN name.

Return type

Iterator[tuple[list[str], dict[str, Union[bytes, bytearray, memoryview]]]]

Returns

iterate a pair (rule_names, context), where rule_names is a list containing corresponding rule names of current node, and context is a dict containing pattern->value mapping.

root_of_trust()

Return the root of signing chains

Return type

set[str]

Returns

a set containing rule names for all starting nodes of signing DAG.

save()

Save the model to bytes. User functions excluded.

Return type

bytes

suggest(pkt_name, keychain)

Suggest a key from the keychain that is used to sign the specific data packet.

Parameters
Return type

List[Union[bytes, bytearray, memoryview]]

Returns

the first key (in the order of storage) in the keychain that can sign the packet

validate_user_fns()

Check if all user functions required by the model is defined.

Return type

bool

class ndn.app_support.light_versec.SemanticError

Raised when the LVS trust schema to compile has semantic errors.

class ndn.app_support.light_versec.LvsModelError

Raised when the input LVS model is malformed.

ndn.app_support.light_versec.checker.UserFn

A UserFn represents a LVS user function. It takes two arguments: the first one is the value of the constrained pattern; the second one is a list consists of all input parameters in the LVS trust schema.

alias of Callable[[Union[bytes, bytearray, memoryview], list[Union[bytes, bytearray, memoryview]]], bool]