Struct galileo_osnma::bitfields::Mack

pub struct Mack<'a, V> { /* private fields */ }

MACK message.

The MACK message, as defined in Figure 8 of the OSNMA ICD.

This is one of the few structs in bitfields that is not a simple wrapper around a slice. The reason is that to interpret the MACK message, it is necessary to know the key and tag sizes, so Mack holds these values as well.

The V type parameter is used to indicate the validation status of the MACK message. Validation of a MACK message corresponds to checking its MACSEQ field and that its ADKDs match the corresponding look-up table. See validation for a description of validation type parameters.

Implementations

impl<'a> Mack<'a, NotValidated>

pub fn new(
    data: &MackMessage,
    key_size: usize,
    tag_size: usize
) -> Mack<'_, NotValidated>

Constructs a new MACK message.

The data should be a reference to an array containing the 60 bytes of the MACK message. The key_size in bits and tag_size in bits should be taken from the parameters of the current TESLA chain. The MACK message is marked as NotValidated.

impl<'a, V> Mack<'a, V>

pub fn key_size(&self) -> usize

Gives the key size in bits corresponding to the MACK message.

This returns the value that has been given in Mack::new.

pub fn tag_size(&self) -> usize

Gives the key size in bits corresponding to the MACK message.

This returns the value that has been given in Mack::new.

pub fn tag0(&self) -> &BitSlice

Gives the tag0 field contained in the MACK header of the MACK message.

See Figure 9 in the OSNMA ICD.

pub fn macseq(&self) -> u16

Gives the value of the MACSEQ field contained in the MACK header of the MACK message.

See Figure 9 in the OSNMA ICD. The MACSEQ is a 12-bit integer, which is returned as a u16.

pub fn num_tags(&self) -> usize

Returns the number of tags in the MACK message.

The number of tags is computed according to the tag size.

pub fn key(&self) -> &BitSlice

Gives the Key field of the MACK message.

This fields contains a TESLA key. See Figure 8 in the OSNMA ICD.

impl<'a, V: Clone> Mack<'a, V>

pub fn tag_and_info(&self, n: usize) -> TagAndInfo<'_, V>

Gives an object representing one of the Tag-Info sections in the MACK message.

The Tag-Info section is defined in Figure 11 of the OSNMA ICD. The parameter n corresponds to the index of the Tag-Info in the MACK message. The first Tag-Info has n = 1, since n = 0 would correspond to the Tag0 field, which does not have an associated info field and is obtained with Mack::tag0.

The validation status of the Tag-Info is inherited from the validation status of the MACK message. There is no way to validate Tag-Info sections once they have been separated from the MACK message. If a validated Tag-Info is needed, the whole MACK message should be validated first using Mack::validate before calling Mack::tag_and_info.

Panics

Panics if n is not between 1 and self.num_tags() - 1.

pub fn validate(
    &self,
    key: &Key<Validated>,
    prna: Svn,
    gst_mack: Gst
) -> Result<Mack<'a, Validated>, MackValidationError>

Try to validate the MACK message.

Given the TESLA key transmitted on the next subframe, this will attempt to validate the MACSEQ field and the ADKD fields of the MACK message. The MACSEQ field is checked using the algorithm in Section 6.6 of the OSNMA ICD. The sequence of ADKD fields is checked against the MAC look-up table using the chain parameters held by the TESLA key.

The parameter prna should be the SVN of the satellite that transmitted this MACK message, and gst_mack corresponds to the GST at the start of the subframe in which the MACK message was transmitted.

If the validation is successful, this returns a copy of self with the validation type parameter V set to Validated. Otherwise, an error indicating which check was not satisfied is returned.

Trait Implementations

impl<'a, V: Clone> Clone for Mack<'a, V>

fn clone(&self) -> Mack<'a, V>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<V: Debug + Clone> Debug for Mack<'_, V>

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

Formats the value using the given formatter.

impl<'a, V: Hash> Hash for Mack<'a, V>

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<'a, V: PartialEq> PartialEq<Mack<'a, V>> for Mack<'a, V>

fn eq(&self, other: &Mack<'a, V>) -> 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<'a, V: Copy> Copy for Mack<'a, V>

impl<'a, V: Eq> Eq for Mack<'a, V>

impl<'a, V> StructuralEq for Mack<'a, V>

impl<'a, V> StructuralPartialEq for Mack<'a, V>