CCSDS File Delivery Protocol (CCSDS 727.0-B-5) for space file transfer
cfdp: fix metadata closure bit and finished delivery/spare bit positions
Interop testing against spacepackets 0.31.0 revealed two bitfield layout
bugs in the CFDP directive codecs:
- Metadata byte: was closure(1)|reserved(3)|checksum(4), actually
reserved(1)|closure(1)|reserved(2)|checksum(4) per CCSDS 727.0-B-5 §5.2.5
- Finished byte: delivery_code and spare bits were swapped. Actual layout
is condition(4)|spare(1)|delivery(1)|file_status(2) per §5.2.3
Both bugs were invisible in roundtrip tests (encode/decode symmetric).
+10
-6
+10
-6
lib/cfdp.ml
+10
-6
lib/cfdp.ml
···
744
744
pfi_file_status : int;
745
745
}
746
746
747
+
(* CCSDS 727.0-B-5 Section 5.2.3: condition(4) | spare(1) | delivery(1) | file_status(2) *)
747
748
let w_fin_condition = Wire.Field.v "condition" (bits8 4)
748
-
let w_fin_delivery = Wire.Field.v "delivery" (bits8 1)
749
749
let w_fin_spare = Wire.Field.v "spare" (bits8 1)
750
+
let w_fin_delivery = Wire.Field.v "delivery" (bits8 1)
750
751
let w_fin_file_status = Wire.Field.v "file_status" (bits8 2)
751
752
752
753
let finished_codec =
753
754
Wire.Codec.v "CfdpFinished"
754
-
(fun condition delivery spare file_status ->
755
+
(fun condition spare delivery file_status ->
755
756
{
756
757
pfi_condition = condition;
757
758
pfi_delivery = delivery;
···
761
762
Wire.Codec.
762
763
[
763
764
(w_fin_condition $ fun f -> f.pfi_condition);
764
-
(w_fin_delivery $ fun f -> f.pfi_delivery);
765
765
(w_fin_spare $ fun f -> f.pfi_spare);
766
+
(w_fin_delivery $ fun f -> f.pfi_delivery);
766
767
(w_fin_file_status $ fun f -> f.pfi_file_status);
767
768
]
768
769
···
827
828
pm_dst_name : string;
828
829
}
829
830
831
+
(* CCSDS 727.0-B-5 Section 5.2.5: reserved(1) | closure(1) | reserved(2) | checksum_type(4) *)
832
+
let w_meta_reserved_hi = Wire.Field.v "reserved_hi" (bits8 1)
830
833
let w_meta_closure = Wire.Field.v "closure" (bits8 1)
831
-
let w_meta_reserved = Wire.Field.v "reserved" (bits8 3)
834
+
let w_meta_reserved = Wire.Field.v "reserved" (bits8 2)
832
835
let w_meta_checksum_type = Wire.Field.v "checksum_type" (bits8 4)
833
836
let w_meta_file_size = Wire.Field.v "file_size" (Wire.byte_array ~size:fss_size)
834
837
···
842
845
843
846
let metadata_codec =
844
847
Wire.Codec.v "CfdpMetadata"
845
-
(fun closure reserved checksum_type file_size src_len src_name dst_len
846
-
dst_name ->
848
+
(fun _reserved_hi closure reserved checksum_type file_size src_len src_name
849
+
dst_len dst_name ->
847
850
{
848
851
pm_closure = closure;
849
852
pm_reserved = reserved;
···
856
859
})
857
860
Wire.Codec.
858
861
[
862
+
(w_meta_reserved_hi $ fun _ -> 0);
859
863
(w_meta_closure $ fun m -> m.pm_closure);
860
864
(w_meta_reserved $ fun m -> m.pm_reserved);
861
865
(w_meta_checksum_type $ fun m -> m.pm_checksum_type);