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start making ECSS checksum optional

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This commit is contained in:
Robin Mueller
2025-09-09 11:11:22 +02:00
parent e151b8e761
commit bf86f58b48
5 changed files with 154 additions and 70 deletions
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31
src/ecss/mod.rs
View File

@@ -373,30 +373,41 @@ pub trait WritablePusPacket {
/// The length here also includes the CRC length.
fn len_written(&self) -> usize;
/// Writes the packet to the given slice without writing the CRC.
///
/// The returned size is the written size WITHOUT the CRC.
fn write_to_bytes_no_crc(&self, slice: &mut [u8]) -> Result<usize, PusError>;
/// Checksum generation is enabled for the packet.
fn has_checksum(&self) -> bool;
/// First uses [Self::write_to_bytes_no_crc] to write the packet to the given slice and then
/// uses the [CRC_CCITT_FALSE] to calculate the CRC and write it to the slice.
/// Writes the packet to the given slice without writing the CRC checksum.
///
/// The returned size is the written size WITHOUT the CRC checksum.
/// If the checksum generation is disabled, this function is identical to the APIs which
/// generate a checksum.
fn write_to_bytes_no_checksum(&self, slice: &mut [u8]) -> Result<usize, PusError>;
/// First uses [Self::write_to_bytes_no_checksum] to write the packet to the given slice and
/// then uses the [CRC_CCITT_FALSE] to calculate the CRC and write it to the slice if the
/// packet is configured to include a checksum.
fn write_to_bytes(&self, slice: &mut [u8]) -> Result<usize, PusError> {
let mut curr_idx = self.write_to_bytes_no_crc(slice)?;
let mut curr_idx = self.write_to_bytes_no_checksum(slice)?;
if self.has_checksum() {
let mut digest = CRC_CCITT_FALSE.digest();
digest.update(&slice[0..curr_idx]);
slice[curr_idx..curr_idx + 2].copy_from_slice(&digest.finalize().to_be_bytes());
curr_idx += 2;
}
Ok(curr_idx)
}
/// First uses [Self::write_to_bytes_no_crc] to write the packet to the given slice and then
/// uses the [CRC_CCITT_FALSE_NO_TABLE] to calculate the CRC and write it to the slice.
fn write_to_bytes_crc_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
let mut curr_idx = self.write_to_bytes_no_crc(slice)?;
/// uses the [CRC_CCITT_FALSE_NO_TABLE] to calculate the CRC and write it to the slice if
/// the paket is configured to include a checksum.
fn write_to_bytes_checksum_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
let mut curr_idx = self.write_to_bytes_no_checksum(slice)?;
if self.has_checksum() {
let mut digest = CRC_CCITT_FALSE_NO_TABLE.digest();
digest.update(&slice[0..curr_idx]);
slice[curr_idx..curr_idx + 2].copy_from_slice(&digest.finalize().to_be_bytes());
curr_idx += 2;
}
Ok(curr_idx)
}

125
src/ecss/tc.rs
View File

@@ -36,7 +36,7 @@
use crate::crc::{CRC_CCITT_FALSE, CRC_CCITT_FALSE_NO_TABLE};
use crate::ecss::{
ccsds_impl, crc_from_raw_data, sp_header_impls, user_data_from_raw,
verify_crc16_ccitt_false_from_raw_to_pus_error, CrcType, PusError, PusPacket, PusVersion,
verify_crc16_ccitt_false_from_raw_to_pus_error, PusError, PusPacket, PusVersion,
WritablePusPacket,
};
use crate::SpHeader;
@@ -55,8 +55,7 @@ use super::verify_crc16_ccitt_false_from_raw_to_pus_error_no_table;
/// PUS C secondary header length is fixed
pub const PUC_TC_SECONDARY_HEADER_LEN: usize = size_of::<zc::PusTcSecondaryHeader>();
pub const PUS_TC_MIN_LEN_WITHOUT_APP_DATA: usize =
CCSDS_HEADER_LEN + PUC_TC_SECONDARY_HEADER_LEN + size_of::<CrcType>();
pub const PUS_TC_MIN_LEN_WITHOUT_APP_DATA: usize = CCSDS_HEADER_LEN + PUC_TC_SECONDARY_HEADER_LEN;
const PUS_VERSION: PusVersion = PusVersion::PusC;
/// Marker trait for PUS telecommand structures.
@@ -234,6 +233,7 @@ pub struct PusTcCreator<'app_data> {
sp_header: SpHeader,
pub sec_header: PusTcSecondaryHeader,
app_data: &'app_data [u8],
has_checksum: bool,
}
impl<'app_data> PusTcCreator<'app_data> {
@@ -249,12 +249,15 @@ impl<'app_data> PusTcCreator<'app_data> {
/// * `set_ccsds_len` - Can be used to automatically update the CCSDS space packet data length
/// field. If this is not set to true, [Self::update_ccsds_data_len] can be called to set
/// the correct value to this field manually
/// * `has_checksum` - A CRC16 checksum will be generated and appended to the end of the
/// packet.
#[inline]
pub fn new(
mut sp_header: SpHeader,
sec_header: PusTcSecondaryHeader,
app_data: &'app_data [u8],
set_ccsds_len: bool,
has_checksum: bool,
) -> Self {
sp_header.set_packet_type(PacketType::Tc);
sp_header.set_sec_header_flag();
@@ -262,6 +265,7 @@ impl<'app_data> PusTcCreator<'app_data> {
sp_header,
app_data,
sec_header,
has_checksum,
};
if set_ccsds_len {
pus_tc.update_ccsds_data_len();
@@ -278,12 +282,14 @@ impl<'app_data> PusTcCreator<'app_data> {
subservice: u8,
app_data: &'app_data [u8],
set_ccsds_len: bool,
has_checksum: bool,
) -> Self {
Self::new(
sph,
PusTcSecondaryHeader::new(service, subservice, ACK_ALL, 0),
app_data,
set_ccsds_len,
has_checksum,
)
}
@@ -292,8 +298,9 @@ impl<'app_data> PusTcCreator<'app_data> {
sp_header: SpHeader,
sec_header: PusTcSecondaryHeader,
set_ccsds_len: bool,
has_checksum: bool,
) -> Self {
Self::new(sp_header, sec_header, &[], set_ccsds_len)
Self::new(sp_header, sec_header, &[], set_ccsds_len, has_checksum)
}
#[inline]
@@ -367,9 +374,12 @@ impl<'app_data> PusTcCreator<'app_data> {
let pus_tc_header = zc::PusTcSecondaryHeader::try_from(self.sec_header).unwrap();
vec.extend_from_slice(pus_tc_header.as_bytes());
vec.extend_from_slice(self.app_data);
if self.has_checksum() {
let mut digest = CRC_CCITT_FALSE.digest();
digest.update(&vec[start_idx..start_idx + appended_len - 2]);
digest.update(&vec[start_idx..start_idx + appended_len]);
vec.extend_from_slice(&digest.finalize().to_be_bytes());
appended_len += 2;
}
appended_len
}
@@ -385,13 +395,13 @@ impl<'app_data> PusTcCreator<'app_data> {
slice: &mut [u8],
) -> Result<usize, ByteConversionError> {
let writer_unfinalized = self.common_write(slice)?;
Ok(writer_unfinalized.finalize_crc_no_table())
Ok(writer_unfinalized.finalize_checksum_no_table())
}
/// Write the raw PUS byte representation to a provided buffer.
pub fn write_to_bytes_no_crc(&self, slice: &mut [u8]) -> Result<usize, ByteConversionError> {
let writer_unfinalized = self.common_write(slice)?;
Ok(writer_unfinalized.finalize_no_crc())
Ok(writer_unfinalized.finalize_no_checksum())
}
fn common_write<'a>(
@@ -409,6 +419,7 @@ impl<'app_data> PusTcCreator<'app_data> {
self.sp_header,
self.sec_header,
self.app_data.len(),
self.has_checksum,
)?;
writer_unfinalized
.app_data_mut()
@@ -420,11 +431,19 @@ impl<'app_data> PusTcCreator<'app_data> {
impl WritablePusPacket for PusTcCreator<'_> {
#[inline]
fn len_written(&self) -> usize {
PUS_TC_MIN_LEN_WITHOUT_APP_DATA + self.app_data.len()
let mut len = PUS_TC_MIN_LEN_WITHOUT_APP_DATA + self.app_data.len();
if self.has_checksum() {
len += 2;
}
len
}
fn has_checksum(&self) -> bool {
self.has_checksum
}
/// Write the raw PUS byte representation to a provided buffer.
fn write_to_bytes_no_crc(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_no_checksum(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_no_crc(self, slice)?)
}
@@ -432,7 +451,7 @@ impl WritablePusPacket for PusTcCreator<'_> {
Ok(Self::write_to_bytes(self, slice)?)
}
fn write_to_bytes_crc_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_checksum_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_crc_no_table(self, slice)?)
}
}
@@ -496,6 +515,7 @@ pub struct PusTcCreatorWithReservedAppData<'buf> {
buf: &'buf mut [u8],
app_data_offset: usize,
full_len: usize,
has_checksum: bool,
}
impl<'buf> PusTcCreatorWithReservedAppData<'buf> {
@@ -514,10 +534,14 @@ impl<'buf> PusTcCreatorWithReservedAppData<'buf> {
mut sp_header: SpHeader,
sec_header: PusTcSecondaryHeader,
app_data_len: usize,
has_checksum: bool,
) -> Result<Self, ByteConversionError> {
sp_header.set_packet_type(PacketType::Tc);
sp_header.set_sec_header_flag();
let len_written = PUS_TC_MIN_LEN_WITHOUT_APP_DATA + app_data_len;
let mut len_written = PUS_TC_MIN_LEN_WITHOUT_APP_DATA + app_data_len;
if has_checksum {
len_written += 2;
}
if len_written > buf.len() {
return Err(ByteConversionError::ToSliceTooSmall {
found: buf.len(),
@@ -525,7 +549,7 @@ impl<'buf> PusTcCreatorWithReservedAppData<'buf> {
});
}
sp_header.data_len = len_written as u16 - size_of::<crate::zc::SpHeader>() as u16 - 1;
Self::write_to_bytes_partially(buf, sp_header, sec_header, app_data_len)
Self::write_to_bytes_partially(buf, sp_header, sec_header, app_data_len, has_checksum)
}
fn write_to_bytes_partially(
@@ -533,6 +557,7 @@ impl<'buf> PusTcCreatorWithReservedAppData<'buf> {
sp_header: SpHeader,
sec_header: PusTcSecondaryHeader,
app_data_len: usize,
has_checksum: bool,
) -> Result<Self, ByteConversionError> {
let mut curr_idx = 0;
sp_header.write_to_be_bytes(&mut buf[0..CCSDS_HEADER_LEN])?;
@@ -545,10 +570,14 @@ impl<'buf> PusTcCreatorWithReservedAppData<'buf> {
curr_idx += sec_header_len;
let app_data_offset = curr_idx;
curr_idx += app_data_len;
if has_checksum {
curr_idx += 2;
}
Ok(Self {
buf,
app_data_offset,
full_len: curr_idx + 2,
full_len: curr_idx,
has_checksum,
})
}
@@ -560,49 +589,74 @@ impl<'buf> PusTcCreatorWithReservedAppData<'buf> {
/// Mutable access to the application data buffer.
#[inline]
pub fn app_data_mut(&mut self) -> &mut [u8] {
&mut self.buf[self.app_data_offset..self.full_len - 2]
let end_index = if self.has_checksum {
self.full_len - 2
} else {
self.full_len
};
&mut self.buf[self.app_data_offset..end_index]
}
/// Access to the source data buffer.
#[inline]
pub fn app_data(&self) -> &[u8] {
&self.buf[self.app_data_offset..self.full_len - 2]
let end_index = if self.has_checksum {
self.full_len - 2
} else {
self.full_len
};
&self.buf[self.app_data_offset..end_index]
}
#[inline]
pub fn app_data_len(&self) -> usize {
self.full_len - 2 - self.app_data_offset
let mut len = self.full_len - self.app_data_offset;
if self.has_checksum {
len -= 2;
}
len
}
/// Finalize the TC packet by calculating and writing the CRC16.
/// Finalize the TC packet by calculating and writing the CRC16 if checksum generation is
/// enabled.
///
/// Returns the full packet length.
pub fn finalize(self) -> usize {
let written_len = self.len_written();
if self.has_checksum {
let mut digest = CRC_CCITT_FALSE.digest();
digest.update(&self.buf[0..self.full_len - 2]);
self.buf[self.full_len - 2..self.full_len]
digest.update(&self.buf[0..written_len - 2]);
self.buf[self.full_len - 2..written_len]
.copy_from_slice(&digest.finalize().to_be_bytes());
self.full_len
}
written_len
}
/// Finalize the TC packet by calculating and writing the CRC16 using a table-less
/// implementation.
/// implementation if checksum genration is enabled.
///
/// Returns the full packet length.
pub fn finalize_crc_no_table(self) -> usize {
pub fn finalize_checksum_no_table(self) -> usize {
let written_len = self.len_written();
if self.has_checksum {
let mut digest = CRC_CCITT_FALSE_NO_TABLE.digest();
digest.update(&self.buf[0..self.full_len - 2]);
self.buf[self.full_len - 2..self.full_len]
digest.update(&self.buf[0..written_len - 2]);
self.buf[self.full_len - 2..written_len]
.copy_from_slice(&digest.finalize().to_be_bytes());
self.full_len
}
written_len
}
/// Finalize the TC packet without writing the CRC16.
/// Finalize the TC packet without writing the CRC16 checksum.
///
/// Returns the length WITHOUT the CRC16.
/// Returns the length WITHOUT the CRC16 checksum.
#[inline]
pub fn finalize_no_crc(self) -> usize {
pub fn finalize_no_checksum(self) -> usize {
if self.has_checksum {
self.full_len - 2
} else {
self.full_len
}
}
}
@@ -796,17 +850,17 @@ mod tests {
fn base_ping_tc_full_ctor() -> PusTcCreator<'static> {
let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
let tc_header = PusTcSecondaryHeader::new_simple(17, 1);
PusTcCreator::new_no_app_data(sph, tc_header, true)
PusTcCreator::new_no_app_data(sph, tc_header, true, true)
}
fn base_ping_tc_simple_ctor() -> PusTcCreator<'static> {
let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
PusTcCreator::new_simple(sph, 17, 1, &[], true)
PusTcCreator::new_simple(sph, 17, 1, &[], true, true)
}
fn base_ping_tc_simple_ctor_with_app_data(app_data: &'static [u8]) -> PusTcCreator<'static> {
let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
PusTcCreator::new_simple(sph, 17, 1, app_data, true)
PusTcCreator::new_simple(sph, 17, 1, app_data, true, true)
}
#[test]
@@ -846,7 +900,8 @@ mod tests {
fn test_serialization_with_trait_2() {
let pus_tc = base_ping_tc_simple_ctor();
let mut test_buf: [u8; 32] = [0; 32];
let size = WritablePusPacket::write_to_bytes_crc_no_table(&pus_tc, test_buf.as_mut_slice())
let size =
WritablePusPacket::write_to_bytes_checksum_no_table(&pus_tc, test_buf.as_mut_slice())
.expect("Error writing TC to buffer");
assert_eq!(size, 13);
assert_eq!(
@@ -885,7 +940,7 @@ mod tests {
fn test_serialization_no_crc_with_trait() {
let pus_tc = base_ping_tc_simple_ctor();
let mut test_buf: [u8; 32] = [0; 32];
let size = WritablePusPacket::write_to_bytes_no_crc(&pus_tc, test_buf.as_mut_slice())
let size = WritablePusPacket::write_to_bytes_no_checksum(&pus_tc, test_buf.as_mut_slice())
.expect("error writing tc to buffer");
assert_eq!(size, 11);
assert_eq!(test_buf[11], 0);
@@ -915,7 +970,7 @@ mod tests {
let tc_header = PusTcSecondaryHeader::new_simple(17, 1);
let mut test_buf: [u8; 32] = [0; 32];
let mut pus_tc =
PusTcCreatorWithReservedAppData::new(&mut test_buf, sph, tc_header, 0).unwrap();
PusTcCreatorWithReservedAppData::new(&mut test_buf, sph, tc_header, 0, true).unwrap();
assert_eq!(pus_tc.len_written(), 13);
assert_eq!(pus_tc.app_data_len(), 0);
assert_eq!(pus_tc.app_data(), &[]);
@@ -965,7 +1020,7 @@ mod tests {
#[test]
fn test_update_func() {
let sph = SpHeader::new_for_unseg_tc_checked(0x02, 0x34, 0).unwrap();
let mut tc = PusTcCreator::new_simple(sph, 17, 1, &[], false);
let mut tc = PusTcCreator::new_simple(sph, 17, 1, &[], false, true);
assert_eq!(tc.data_len(), 0);
tc.update_ccsds_data_len();
assert_eq!(tc.data_len(), 6);

14
src/ecss/tc_pus_a.rs
View File

@@ -469,8 +469,13 @@ impl WritablePusPacket for PusTcCreator<'_> {
CCSDS_HEADER_LEN + self.sec_header.written_len() + self.app_data.len() + 2
}
/// Currently, checksum is always added.
fn has_checksum(&self) -> bool {
true
}
/// Write the raw PUS byte representation to a provided buffer.
fn write_to_bytes_no_crc(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_no_checksum(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_no_crc(self, slice)?)
}
@@ -478,7 +483,7 @@ impl WritablePusPacket for PusTcCreator<'_> {
Ok(Self::write_to_bytes(self, slice)?)
}
fn write_to_bytes_crc_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_checksum_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_crc_no_table(self, slice)?)
}
}
@@ -898,7 +903,8 @@ mod tests {
fn test_serialization_with_trait_2() {
let pus_tc = base_ping_tc_simple_ctor();
let mut test_buf: [u8; 32] = [0; 32];
let size = WritablePusPacket::write_to_bytes_crc_no_table(&pus_tc, test_buf.as_mut_slice())
let size =
WritablePusPacket::write_to_bytes_checksum_no_table(&pus_tc, test_buf.as_mut_slice())
.expect("Error writing TC to buffer");
assert_eq!(size, 11);
assert_eq!(
@@ -937,7 +943,7 @@ mod tests {
fn test_serialization_no_crc_with_trait() {
let pus_tc = base_ping_tc_simple_ctor();
let mut test_buf: [u8; 32] = [0; 32];
let size = WritablePusPacket::write_to_bytes_no_crc(&pus_tc, test_buf.as_mut_slice())
let size = WritablePusPacket::write_to_bytes_no_checksum(&pus_tc, test_buf.as_mut_slice())
.expect("error writing tc to buffer");
assert_eq!(size, 9);
assert_eq!(test_buf[9], 0);

10
src/ecss/tm.rs
View File

@@ -463,8 +463,14 @@ impl WritablePusPacket for PusTmCreator<'_, '_> {
+ self.sec_header.timestamp.len()
+ self.source_data.len()
}
/// Currently, checksum is always added.
fn has_checksum(&self) -> bool {
true
}
/// Write the raw PUS byte representation to a provided buffer.
fn write_to_bytes_no_crc(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_no_checksum(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_no_crc(self, slice)?)
}
@@ -472,7 +478,7 @@ impl WritablePusPacket for PusTmCreator<'_, '_> {
Ok(Self::write_to_bytes(self, slice)?)
}
fn write_to_bytes_crc_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_checksum_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_crc_no_table(self, slice)?)
}
}

10
src/ecss/tm_pus_a.rs
View File

@@ -508,8 +508,14 @@ impl WritablePusPacket for PusTmCreator<'_, '_> {
fn len_written(&self) -> usize {
CCSDS_HEADER_LEN + self.sec_header.written_len() + self.source_data.len() + 2
}
/// Currently, checksum is always added.
fn has_checksum(&self) -> bool {
true
}
/// Write the raw PUS byte representation to a provided buffer.
fn write_to_bytes_no_crc(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_no_checksum(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_no_crc(self, slice)?)
}
@@ -517,7 +523,7 @@ impl WritablePusPacket for PusTmCreator<'_, '_> {
Ok(Self::write_to_bytes(self, slice)?)
}
fn write_to_bytes_crc_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
fn write_to_bytes_checksum_no_table(&self, slice: &mut [u8]) -> Result<usize, PusError> {
Ok(Self::write_to_bytes_crc_no_table(self, slice)?)
}
}