Struct galileo_osnma::tesla::Chain

pub struct Chain { /* private fields */ }

TESLA chain parameters.

This struct stores the parameters of a TESLA chain. It is typically constructed from a DSK-KROOT message using Chain::from_dsm_kroot.

Implementations

impl Chain

pub fn from_dsm_kroot(
    nma_header: NmaHeader<'_>,
    dsm_kroot: DsmKroot<'_>
) -> Result<Chain, ChainError>

Extract the chain parameters from a DSM-KROOT message.

The corresponding NMA header needs to be given, in order to extract the ChainStatus from the NMA status field.

If all the values in the DSM-KROOT message are acceptable a Chain is returned. Otherwise, this returns an error indicating the problem.

pub fn chain_status(&self) -> ChainStatus

Gives the status of the TESLA chain.

pub fn chain_id(&self) -> u8

Gives the chain ID of the TESLA chain.

pub fn hash_function(&self) -> HashFunction

Gives the hash function used by the TESLA chain.

pub fn mac_function(&self) -> MacFunction

Gives the MAC function used by the TESLA chain.

pub fn key_size_bytes(&self) -> usize

Gives the size of the TESLA keys in bytes.

Note that all the possible TESLA key sizes are an integer number of bytes.

pub fn key_size_bits(&self) -> usize

Gives the size of the TESLA keys in bits.

pub fn tag_size_bits(&self) -> usize

Gives the size of the tags in bits.

Note that there are some possible tag sizes which are not an integer number of bytes.

pub fn mac_lookup_table(&self) -> u8

Gives the value of the MAC look-up table field.

pub fn alpha(&self) -> u64

Gives the value of the chain random parameter alpha.

pub fn validate_adkd<V>(
    &self,
    num_tag: usize,
    tag: TagAndInfo<'_, V>,
    prna: Svn,
    gst_tag: Gst
) -> Result<(), AdkdCheckError>

Try to validate the ADKD field of a Tag-Info section.

This checks the ADKD against the MAC look-up table as described in Annex C of the OSNMA ICD. If the ADKD field is correct, this returns Ok(()). Otherwise, this returns an error indicating what property is not satisfied.

The num_tag parameter gives the index of the Tag-Info field. This is the same index that is used in Mack::tag_and_info. The first Tag-Info field in a MACK message has num_tag = 1. The prna parameter indicates the SVN of the satellite that transmitted the tag, and gst_tag is the GST at the start of the subframe when the tag was transmitted.

Panics

Panics if num_tag is zero.

Trait Implementations

impl Clone for Chain

fn clone(&self) -> Chain

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Chain

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for Chain

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,

Feeds a slice of this type into the given Hasher.

impl PartialEq<Chain> for Chain

fn eq(&self, other: &Chain) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Chain

impl Eq for Chain

impl StructuralEq for Chain

impl StructuralPartialEq for Chain