The net_core:process_data() and connection:net_conn_input() methods are
the central network packet reception pipeline which:
1) guide network packets through all network layers,
2) decode, validate and filter packages along the way and
3) distribute packages to connections/sockets on all layers.
This code seems to have grown complex and rather cluttered over time as
all protocols, layers and socket implementations meet there in one single
place.
The code also reveals its origin as a pure IP stack which makes it hard
to introduce non-IP protocols and their supporting socket infrastructure
in a modularized way.
For an outside contributor it seems almost impossible to add another
protocol, protocol layer, filter rule or socket implementation without
breaking things.
This change doesn't try to solve all issues at once. It focuses
exclusively on aspects that maintain backwards compatibility:
* Improve modularization and encapsulation on implementation level by
disentangling code that mixes up layers, protocols and socket
implementations.
* Make IP just one protocol among others by removing assymmetry in
protocol handling logic and introduce preprocessor markup so that
IP-specific code can be eliminated by the preprocessor if not needed.
* Use preprocessor markup to delineate hook points for future
modularization or expansion without introducing structural changes (as
this would almost certainly break the API).
* Reduce cyclomatic complexity, use positive rather than negative logic,
improve variable naming, replace if/elseif/else blocks with switches,
reduce variable span, introduce inline comments where code does not
speak for itself, etc. as much as possible to make the code overall
more human-friendly.
Background: These are preparative steps for the introduction of IEEE
802.15.RAW sockets, DGRAM sockets and sockets bound to PAN IDs and device
addresses similar to what the Linux kernel does.
Signed-off-by: Florian Grandel <jerico.dev@gmail.com>
Rename the SocketCAN header from socket_can.h to socketcan.h to better
match the naming of the functionality.
Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>
In order to bring consistency in-tree, migrate all subsystems code to
the new prefix <zephyr/...>. Note that the conversion has been scripted,
refer to zephyrproject-rtos#45388 for more details.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
This commit is an implementation of 6LoCAN, a 6Lo adaption layer for
Controller Area Networks. 6LoCAN is not yet standardised.
Signed-off-by: Alexander Wachter <alexander.wachter@student.tugraz.at>
