//! ECSS PUS packet routing components.
//!
//! The routing components consist of two core components:
//! 1. [PusDistributor] component which dispatches received packets to a user-provided handler.
//! 2. [PusServiceProvider] trait which should be implemented by the user-provided PUS packet
//! handler.
//!
//! The [PusDistributor] implements the [ReceivesEcssPusTc], [ReceivesCcsdsTc] and the [ReceivesTc]
//! trait which allows to pass raw packets, CCSDS packets and PUS TC packets into it.
//! Upon receiving a packet, it performs the following steps:
//!
//! 1. It tries to extract the [SpHeader] and [PusTc] objects from the raw bytestream. If this
//! process fails, a [PusDistribError::PusError] is returned to the user.
//! 2. If it was possible to extract both components, the packet will be passed to the
//! [PusServiceProvider::handle_pus_tc_packet] method provided by the user.
//!
//! # Example
//!
//! ```rust
//! use fsrc_core::tmtc::pus_distrib::{PusDistributor, PusServiceProvider};
//! use fsrc_core::tmtc::ReceivesTc;
//! use spacepackets::SpHeader;
//! use spacepackets::tc::PusTc;
//! struct ConcretePusHandler {
//! handler_call_count: u32
//! }
//!
//! // This is a very simple possible service provider. It increments an internal call count field,
//! // which is used to verify the handler was called
//! impl PusServiceProvider for ConcretePusHandler {
//! type Error = ();
//! fn handle_pus_tc_packet(&mut self, service: u8, header: &SpHeader, pus_tc: &PusTc) -> Result<(), Self::Error> {
//! assert_eq!(service, 17);
//! assert_eq!(pus_tc.len_packed(), 13);
//! self.handler_call_count += 1;
//! Ok(())
//! }
//! }
//!
//! let service_handler = ConcretePusHandler {
//! handler_call_count: 0
//! };
//! let mut pus_distributor = PusDistributor::new(Box::new(service_handler));
//!
//! // Create and pass PUS ping telecommand with a valid APID
//! let mut space_packet_header = SpHeader::tc(0x002, 0x34, 0).unwrap();
//! let mut pus_tc = PusTc::new_simple(&mut space_packet_header, 17, 1, None, true);
//! let mut test_buf: [u8; 32] = [0; 32];
//! let mut size = pus_tc
//! .write_to(test_buf.as_mut_slice())
//! .expect("Error writing TC to buffer");
//! let tc_slice = &test_buf[0..size];
//!
//! pus_distributor.pass_tc(tc_slice).expect("Passing PUS telecommand failed");
//!
//! // User helper function to retrieve concrete class. We check the call count here to verify
//! // that the PUS ping telecommand was routed successfully.
//! let concrete_handler_ref: &ConcretePusHandler = pus_distributor
//! .service_provider_ref()
//! .expect("Casting back to concrete type failed");
//! assert_eq!(concrete_handler_ref.handler_call_count, 1);
//! ```
use crate::tmtc::{ReceivesCcsdsTc, ReceivesEcssPusTc, ReceivesTc};
use downcast_rs::Downcast;
use spacepackets::ecss::{PusError, PusPacket};
use spacepackets::tc::PusTc;
use spacepackets::SpHeader;
pub trait PusServiceProvider: Downcast {
type Error;
fn handle_pus_tc_packet(
&mut self,
service: u8,
header: &SpHeader,
pus_tc: &PusTc,
) -> Result<(), Self::Error>;
}
downcast_rs::impl_downcast!(PusServiceProvider assoc Error);
pub struct PusDistributor<E> {
pub service_provider: Box<dyn PusServiceProvider<Error = E>>,
}
impl<E> PusDistributor<E> {
pub fn new(service_provider: Box<dyn PusServiceProvider<Error = E>>) -> Self {
PusDistributor { service_provider }
}
}
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum PusDistribError<E> {
CustomError(E),
PusError(PusError),
}
impl<E> ReceivesTc for PusDistributor<E> {
type Error = PusDistribError<E>;
fn pass_tc(&mut self, tm_raw: &[u8]) -> Result<(), Self::Error> {
// Convert to ccsds and call pass_ccsds
let sp_header = SpHeader::from_raw_slice(tm_raw)
.map_err(|e| PusDistribError::PusError(PusError::PacketError(e)))?;
self.pass_ccsds(&sp_header, tm_raw)
}
}
impl<E> ReceivesCcsdsTc for PusDistributor<E> {
type Error = PusDistribError<E>;
fn pass_ccsds(&mut self, header: &SpHeader, tm_raw: &[u8]) -> Result<(), Self::Error> {
let (tc, _) =
PusTc::new_from_raw_slice(tm_raw).map_err(|e| PusDistribError::PusError(e))?;
self.pass_pus_tc(header, &tc)
}
}
impl<E> ReceivesEcssPusTc for PusDistributor<E> {
type Error = PusDistribError<E>;
fn pass_pus_tc(&mut self, header: &SpHeader, pus_tc: &PusTc) -> Result<(), Self::Error> {
self.service_provider
.handle_pus_tc_packet(pus_tc.service(), header, pus_tc)
.map_err(|e| PusDistribError::CustomError(e))
}
}
impl<E: 'static> PusDistributor<E> {
pub fn service_provider_ref<T: PusServiceProvider<Error = E>>(&self) -> Option<&T> {
self.service_provider.downcast_ref::<T>()
}
pub fn service_provider_mut<T: PusServiceProvider<Error = E>>(&mut self) -> Option<&mut T> {
self.service_provider.downcast_mut::<T>()
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::error::SimpleStdErrorHandler;
use crate::tmtc::ccsds_distrib::tests::{
generate_ping_tc, BasicApidHandlerOwnedQueue, BasicApidHandlerSharedQueue,
};
use crate::tmtc::ccsds_distrib::{ApidPacketHandler, CcsdsDistributor};
use spacepackets::ecss::PusError;
use spacepackets::tc::PusTc;
use spacepackets::CcsdsPacket;
use std::collections::VecDeque;
use std::sync::{Arc, Mutex};
struct PusHandlerSharedQueue {
pub pus_queue: Arc<Mutex<VecDeque<(u8, u16, Vec<u8>)>>>,
}
#[derive(Default)]
struct PusHandlerOwnedQueue {
pub pus_queue: VecDeque<(u8, u16, Vec<u8>)>,
}
impl PusServiceProvider for PusHandlerSharedQueue {
type Error = PusError;
fn handle_pus_tc_packet(
&mut self,
service: u8,
sp_header: &SpHeader,
pus_tc: &PusTc,
) -> Result<(), Self::Error> {
let mut vec: Vec<u8> = Vec::new();
pus_tc.append_to_vec(&mut vec)?;
Ok(self
.pus_queue
.lock()
.expect("Mutex lock failed")
.push_back((service, sp_header.apid(), vec)))
}
}
impl PusServiceProvider for PusHandlerOwnedQueue {
type Error = PusError;
fn handle_pus_tc_packet(
&mut self,
service: u8,
sp_header: &SpHeader,
pus_tc: &PusTc,
) -> Result<(), Self::Error> {
let mut vec: Vec<u8> = Vec::new();
pus_tc.append_to_vec(&mut vec)?;
Ok(self.pus_queue.push_back((service, sp_header.apid(), vec)))
}
}
struct ApidHandlerShared {
pub pus_distrib: PusDistributor<PusError>,
pub handler_base: BasicApidHandlerSharedQueue,
}
struct ApidHandlerOwned {
pub pus_distrib: PusDistributor<PusError>,
handler_base: BasicApidHandlerOwnedQueue,
}
macro_rules! apid_handler_impl {
() => {
type Error = PusError;
fn valid_apids(&self) -> &'static [u16] {
&[0x000, 0x002]
}
fn handle_known_apid(
&mut self,
sp_header: &SpHeader,
tc_raw: &[u8],
) -> Result<(), Self::Error> {
self.handler_base
.handle_known_apid(&sp_header, tc_raw)
.ok()
.expect("Unexpected error");
match self.pus_distrib.pass_ccsds(&sp_header, tc_raw) {
Ok(_) => Ok(()),
Err(e) => match e {
PusDistribError::CustomError(_) => Ok(()),
PusDistribError::PusError(e) => Err(e),
},
}
}
fn handle_unknown_apid(
&mut self,
sp_header: &SpHeader,
tc_raw: &[u8],
) -> Result<(), Self::Error> {
self.handler_base
.handle_unknown_apid(&sp_header, tc_raw)
.ok()
.expect("Unexpected error");
Ok(())
}
};
}
impl ApidPacketHandler for ApidHandlerOwned {
apid_handler_impl!();
}
impl ApidPacketHandler for ApidHandlerShared {
apid_handler_impl!();
}
#[test]
fn test_pus_distribution() {
let known_packet_queue = Arc::new(Mutex::default());
let unknown_packet_queue = Arc::new(Mutex::default());
let pus_queue = Arc::new(Mutex::default());
let pus_handler = PusHandlerSharedQueue {
pus_queue: pus_queue.clone(),
};
let handler_base = BasicApidHandlerSharedQueue {
known_packet_queue: known_packet_queue.clone(),
unknown_packet_queue: unknown_packet_queue.clone(),
};
let error_handler = SimpleStdErrorHandler {};
let pus_distrib = PusDistributor {
service_provider: Box::new(pus_handler),
};
let apid_handler = ApidHandlerShared {
pus_distrib,
handler_base,
};
let mut ccsds_distrib =
CcsdsDistributor::new(Box::new(apid_handler), Box::new(error_handler));
let mut test_buf: [u8; 32] = [0; 32];
let tc_slice = generate_ping_tc(test_buf.as_mut_slice());
// Pass packet to distributor
ccsds_distrib
.pass_tc(tc_slice)
.expect("Passing TC slice failed");
let recvd_ccsds = known_packet_queue.lock().unwrap().pop_front();
assert!(unknown_packet_queue.lock().unwrap().is_empty());
assert!(recvd_ccsds.is_some());
let (apid, packet) = recvd_ccsds.unwrap();
assert_eq!(apid, 0x002);
assert_eq!(packet.as_slice(), tc_slice);
let recvd_pus = pus_queue.lock().unwrap().pop_front();
assert!(recvd_pus.is_some());
let (service, apid, tc_raw) = recvd_pus.unwrap();
assert_eq!(service, 17);
assert_eq!(apid, 0x002);
assert_eq!(tc_raw, tc_slice);
}
#[test]
fn test_as_any_cast() {
let pus_handler = PusHandlerOwnedQueue::default();
let handler_base = BasicApidHandlerOwnedQueue::default();
let error_handler = SimpleStdErrorHandler {};
let pus_distrib = PusDistributor {
service_provider: Box::new(pus_handler),
};
let apid_handler = ApidHandlerOwned {
pus_distrib,
handler_base,
};
let mut ccsds_distrib =
CcsdsDistributor::new(Box::new(apid_handler), Box::new(error_handler));
let mut test_buf: [u8; 32] = [0; 32];
let tc_slice = generate_ping_tc(test_buf.as_mut_slice());
ccsds_distrib
.pass_tc(tc_slice)
.expect("Passing TC slice failed");
let apid_handler_casted_back: &mut ApidHandlerOwned = ccsds_distrib
.apid_handler_mut()
.expect("Cast to concrete type ApidHandler failed");
assert!(!apid_handler_casted_back
.handler_base
.known_packet_queue
.is_empty());
let handler_casted_back: &mut PusHandlerOwnedQueue = apid_handler_casted_back
.pus_distrib
.service_provider_mut()
.expect("Cast to concrete type PusHandlerOwnedQueue failed");
assert!(!handler_casted_back.pus_queue.is_empty());
let (service, apid, packet_raw) = handler_casted_back.pus_queue.pop_front().unwrap();
assert_eq!(service, 17);
assert_eq!(apid, 0x002);
assert_eq!(packet_raw.as_slice(), tc_slice);
}
}