<s>
CubeSat	B-Protocol
Space	I-Protocol
Protocol	I-Protocol
(	O
CSP	O
)	O
is	O
a	O
small	O
network-layer	O
delivery	O
protocol	O
designed	O
for	O
CubeSats	O
.	O
</s>
<s>
The	O
implementation	O
is	O
written	O
in	O
C	B-Language
and	O
is	O
ported	O
to	O
run	O
on	O
FreeRTOS	B-Operating_System
and	O
POSIX	O
and	O
pthreads-based	O
operating	O
systems	O
such	O
as	O
Linux	B-Application
.	O
</s>
<s>
The	O
three-letter	O
acronym	O
CSP	O
was	O
adopted	O
as	O
an	O
abbreviation	O
for	O
CAN	B-Protocol
Space	O
Protocol	O
because	O
the	O
first	O
MAC-layer	O
driver	O
was	O
written	O
for	O
CAN-bus	B-Protocol
.	O
</s>
<s>
The	O
physical	O
layer	O
has	O
since	O
been	O
extended	O
to	O
include	O
several	O
other	O
technologies	O
,	O
and	O
the	O
name	O
was	O
therefore	O
extended	O
to	O
the	O
more	O
general	O
CubeSat	B-Protocol
Space	I-Protocol
Protocol	I-Protocol
without	O
changing	O
the	O
abbreviation	O
.	O
</s>
<s>
The	O
source	O
code	O
is	O
available	O
under	O
an	O
LGPL	B-Application
license	I-Application
and	O
hosted	O
on	O
GitHub	B-Application
.	O
</s>
<s>
The	O
CubeSat	B-Protocol
Space	I-Protocol
Protocol	I-Protocol
enables	O
distributed	O
embedded	O
systems	O
to	O
deploy	O
a	O
service-oriented	O
network	O
topology	O
.	O
</s>
<s>
The	O
layering	O
of	O
CSP	O
corresponds	O
to	O
the	O
same	O
layers	O
as	O
the	O
TCP/IP	B-Protocol
model	I-Protocol
.	O
</s>
<s>
Simple	O
API	B-Application
similar	O
to	O
Berkeley	B-Protocol
sockets	I-Protocol
.	O
</s>
<s>
Support	O
for	O
both	O
connectionless	O
operation	O
(	O
similar	O
to	O
UDP	B-Protocol
)	O
,	O
and	O
connection	O
oriented	O
operation	O
(	O
based	O
on	O
RUDP	B-Protocol
)	O
.	O
</s>
<s>
Service	O
handler	O
that	O
implements	O
ICMP-like	O
requests	O
such	O
as	O
ping	O
and	O
buffer	O
status	O
.	O
</s>
<s>
This	O
can	B-Protocol
e.g.	O
</s>
<s>
be	O
used	O
for	O
Inter-process	B-Operating_System
communication	I-Operating_System
between	O
subsystem	O
tasks	O
.	O
</s>
<s>
Optional	O
support	O
for	O
encrypted	O
packets	O
with	O
XTEA	B-Algorithm
in	O
CTR	B-Algorithm
mode	O
.	O
</s>
<s>
Optional	O
support	O
for	O
HMAC	B-Algorithm
authenticated	O
packets	O
with	O
truncated	O
SHA-1	B-Algorithm
HMAC	B-Algorithm
.	O
</s>
<s>
CSP	O
should	O
compile	O
on	O
all	O
platforms	O
that	O
have	O
a	O
recent	O
version	O
of	O
the	O
gcc	B-Application
compiler	I-Application
.	O
</s>
<s>
CSP	O
requires	O
support	O
for	O
C99	B-Language
features	O
such	O
as	O
inline	O
functions	O
and	O
designated	O
initializers	O
.	O
</s>
<s>
FreeRTOS	B-Operating_System
–	O
Tested	O
on	O
AVR8	B-Architecture
,	O
AVR32	B-Device
and	O
ARM7	O
.	O
</s>
<s>
Linux	B-Application
–	O
Tested	O
on	O
x86	B-Operating_System
,	O
x86-64	B-Device
and	O
Blackfin	B-General_Concept
.	O
</s>
<s>
The	O
LGPL	B-Application
licensed	O
source	O
code	O
contains	O
an	O
implementation	O
of	O
a	O
fragmenting	O
CAN	B-Protocol
interface	O
and	O
drivers	O
for	O
SocketCAN	B-Application
and	O
the	O
Atmel	O
AT90CAN128	O
,	O
AT91SAM7A1	O
and	O
AT91SAM7A3	O
processors	O
.	O
</s>
<s>
The	O
bits	O
from	O
28	O
to	O
31	O
are	O
used	O
for	O
marking	O
packets	O
with	O
HMAC	B-Algorithm
,	O
XTEA	B-Algorithm
encryption	O
,	O
RDP	O
header	O
and	O
CRC32	O
checksum	O
.	O
</s>
