drivers/slipmux: Rework SLIPDEV driver in preparation for Unicoap #21907

Teufelchen1 · 2025-11-21T20:02:36Z

Contribution description

Hey hey 🦭

This refactors the current slipdev driver heavily and also renames it to slipmux.

The networking aspect (plain slip) is no longer the default but a submodule: slipmux_net.
The "configuration" aspect (coap via uart) is no longer called slipdev_config but slipmux_coap. That moves it further from the slipmux draft but (I hope) closer to the average developer and sets the expectations clearer.
Same for diagnostic but there it was already called _stdio which was retained.

There is a new "overall" module called slipmux which enables all three modes (slipmux_stdio, _coap and _net) for full slipmux functionality.

The parser behavior got a slight change and differentiates between unknown frame types and IPv4/6 frames now. This should make it more robust when interfacing slipmux instead of slip. (Worry not, our slip tools still work as expected)

In addition, the coap handling got reworked to be ready for plug & play action with unicoap once #21582 is merged.

Testing procedure

Pick one of our examples that offer slip e.g. examples/networking/gnrc/border_router/ and see that it still behaves as advertised in the README. tl;dr:

cd examples/networking/gnrc/border_router/
BOARD=nrf52840dk UPLINK=slip make all flash -j9 term
Building application "gnrc_border_router" for "nrf52840dk" with CPU "nrf52".
[...]
> 
> ifconfig
Iface  2 
          MTU:65535  HL:64  RTR  
          
          Link type: wired
          inet6 addr: fe80::2  scope: link  VAL
          inet6 group: ff02::1:ff00:2
          
Iface  6  HWaddr: 35:3F  Channel: 26  NID: 0x23  PHY: O-QPSK 
         [...]
          inet6 group: ff02::1:ff22:b53f
          
ps
> ps
	pid | name                 | state    Q | pri | stack  ( used) ( free) | base addr  | current     
	  - | isr_stack            | -        - |   - |    512 (  224) (  288) | 0x20000000 | 0x200001c8
	  1 | main                 | running  Q |   7 |   1536 (  904) (  632) | 0x200002f0 | 0x2000062c 
	  2 | slipdev              | bl anyfl _ |   2 |    896 (  284) (  612) | 0x20004af4 | 0x20004db4 
	 [...]
	  7 | uhcp                 | bl mutex _ |   6 |   1536 (  944) (  592) | 0x200040bc | 0x200044d4 
	    | SUM                  |            |     |   7744 ( 3388) ( 4356)

See the slipdev thread running (pid 2) and then try to ping the border router from your linux console:

 ~> ping fe80::2%sl0
PING fe80::2%sl0 (fe80::2%sl0) 56 data bytes
64 bytes from fe80::2%sl0: icmp_seq=1 ttl=64 time=20.1 ms
64 bytes from fe80::2%sl0: icmp_seq=2 ttl=64 time=20.5 ms
^C
--- fe80::2%sl0 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 20.108/20.287/20.466/0.179 ms

Teufelchen1 · 2025-11-21T20:04:08Z

drivers/slipmux/coap.c

+    while (1) {
+        event_t *event = event_wait(&queue);
+        event->handler(event);
+    }


This whole event queue contraption is rather odd but it will fit nicely with unicoap, trust me bro.

riot-ci · 2025-11-21T22:54:17Z

Murdock results

❌ FAILED

27af9a1 unfinished Kconf

Build failures (14)

Application	Target	Toolchain	Runtime (s)	Worker
tests/net/slip	native64	gnu	0.29	alien
tests/net/slip	samr21-xpro	llvm	0.80	alien
tests/net/slip	native64	llvm	0.53	alien
tests/net/slip	msb-430	gnu	0.37	alien
tests/net/slip	native32	gnu	1.22	mobi6
tests/net/slip	msba2	gnu	1.26	mobi6
tests/net/slip	samr21-xpro	gnu	0.54	alien
tests/net/slip	frdm-k64f	gnu	1.79	mobi6
tests/net/slip	adafruit-itsybitsy-m4	gnu	1.86	mobi6
tests/net/slip	qn9080dk	gnu	1.83	mobi6
tests/net/slip	stm32f429i-disc1	gnu	0.84	alien
tests/net/slip	native32	llvm	3.98	skyleaf
tests/net/slip	nrf52840dk	gnu	2.67	tatooine
tests/net/slip	stk3200	gnu	3.08	mobi6

Artifacts

crasbe

Just some basic style and nitpick comments for now.

Also the static test has some ideas and you sometimes added yourself in the Copyright and sometimes in the Doxygen authorship, but not really consistently yet 🤔

drivers/include/slipmux.h

drivers/slipmux/coap.c

drivers/slipmux/include/slipmux_internal.h

drivers/slipmux/include/slipmux_params.h

drivers/slipmux/net.c

crasbe · 2025-11-21T23:03:12Z

makefiles/pseudomodules.inc.mk

-PSEUDOMODULES += slipdev_stdio
-PSEUDOMODULES += slipdev_config
-PSEUDOMODULES += slipdev_l2addr


We don't need these modules as slipmux_ PSEUDOMODULES anymore?

We still do! And this actually one of the major reasons for this rewrite/refactoring: The ability to select _stdio or _coap (used to be _config) without having to use _net (used to not exist and was always included in the base slipdev)

The definitions moved into Makefile.include. I can't remember why I decided to move them out of the global pseudomodules.inc.mk. Either a mistake or some deeper reasoning? Will see in a bit.

Teufelchen1 · 2025-11-24T10:26:45Z

Just some basic style and nitpick comments for now.

Way too early :p but thanks anyways, I adopted the fixes.

Also the static test has some ideas

Probably. I wasn't done-enough yet, to look at them.

[..] and you sometimes added yourself in the Copyright and sometimes in the Doxygen authorship, but not really consistently yet 🤔

No care was given to that yet.

sys/shell/cmds/gnrc_netif.c

tests/net/slip/Makefile

Teufelchen1 · 2025-11-24T17:03:01Z

I think this is ready for actual review now. I would appreciate feedback specifically on the mutex handling. I am not super proud of it.

crasbe · 2025-11-24T17:05:29Z

If you want to, you can squash before the reviews start pouring in 🤔

mguetschow

Great stuff! ❤️ Unfortunately it was a bit hard to review since Github didn't properly display the file renames (separate commit would have helped).

I've got mostly nitpicky things and haven't tested this yet.

Also Murdock fails because you probably have to change the Kconfig include from slipdev to slipmux somewhere.

drivers/include/slipmux.h

drivers/slipmux/net.c

mguetschow · 2025-11-26T10:34:08Z

drivers/slipmux/net.c

+#if IS_USED(MODULE_SLIPMUX_NET_L2ADDR)
+        case NETOPT_ADDRESS_LONG:
+            assert(max_len == sizeof(eui64_t));
+            netdev_eui64_get(netdev, value);
+            return sizeof(eui64_t);
+#endif


What about this is slipmux-specific? why not use a generic l2addr module? I have the feeling there was some, maybe I'm wrong.

No idea, I honestly didn't question it. It works tho! Tested it! :P

drivers/slipmux/net.c

examples/networking/coap/gcoap/README-slip.md

mguetschow · 2025-11-26T10:39:55Z

CODEOWNERS

 /drivers/si70xx/                            @basilfx
-/drivers/slipdev/                           @miri64
 /drivers/sx127x/                            @aabadie @jia200x


Suggested change

/drivers/si70xx/ @basilfx

/drivers/slipdev/ @miri64

/drivers/sx127x/ @aabadie @jia200x

/drivers/si70xx/ @basilfx

/drivers/slipmux/ @Teufelchen1

/drivers/sx127x/ @aabadie @jia200x

:P

mguetschow

Forgot the most important file :P

drivers/slipmux/coap.c

mguetschow · 2025-11-26T10:47:59Z

drivers/slipmux/coap.c

+        if (len <= 0) {
+            return;


some DEBUG messages wouldn't harm :)

mguetschow · 2025-11-26T14:24:37Z

Btw, while editing the title I was thinking: does this really belong to drivers and not rather sys/net?

Teufelchen1 · 2025-11-27T13:02:09Z

Great stuff! ❤️

Thanks!

Unfortunately it was a bit hard to review since Github didn't properly display the file renames (separate commit would have helped).

Yes, I realized too late that this approach was shit (sorry!).

does this really belong to drivers and not rather sys/net?

I don't know. 🙈

Teufelchen1 requested review from MrKevinWeiss, jia200x, leandrolanzieri and miri64 as code owners November 21, 2025 20:02

Teufelchen1 commented Nov 21, 2025

View reviewed changes

crasbe added Type: enhancement The issue suggests enhanceable parts / The PR enhances parts of the codebase / documentation CI: ready for build If set, CI server will compile all applications for all available boards for the labeled PR labels Nov 21, 2025

crasbe reviewed Nov 21, 2025

View reviewed changes

crasbe added the CI: no fast fail don't abort PR build after first error label Nov 24, 2025

github-actions bot added Area: doc Area: Documentation Area: tests Area: tests and testing framework labels Nov 24, 2025

Teufelchen1 commented Nov 24, 2025

View reviewed changes

sys/shell/cmds/gnrc_netif.c Show resolved Hide resolved

Teufelchen1 commented Nov 24, 2025

View reviewed changes

tests/net/slip/Makefile Show resolved Hide resolved

Teufelchen1 force-pushed the slipmux_event_based branch 2 times, most recently from 9e542dd to 33e529a Compare November 24, 2025 15:07

Teufelchen1 changed the title ~~DRAFT: Rework SLIPDEV driver in preparation for Unicoap~~ Rework SLIPDEV driver in preparation for Unicoap Nov 24, 2025

drivers/slipmux: Rework slipdev driver and renaming

25826ef

Teufelchen1 force-pushed the slipmux_event_based branch from a64fda5 to 25826ef Compare November 24, 2025 17:14

mguetschow requested changes Nov 26, 2025

View reviewed changes

mguetschow reviewed Nov 26, 2025

View reviewed changes

mguetschow changed the title ~~Rework SLIPDEV driver in preparation for Unicoap~~ drivers/slipmux: Rework SLIPDEV driver in preparation for Unicoap Nov 26, 2025

Teufelchen1 added 12 commits November 27, 2025 10:56

remove nolonger needed mutex

4f56cb5

review: fix doc issues in headers

9a5b785

doc fixes

8c5e46a

add docs for _net_l2addr

f22fbf1

fix wrong module name

6aa2df2

remove slipdev debris

dcd6f15

review: adjust net.c

848ab3d

lol forgot to commit, use new state names

b771105

typedef the state

690c9c3

add unknown frame type

71ad6d4

remove trailing whitespace

69f3d50

unfinished Kconf

27af9a1

drivers/slipmux: Rework SLIPDEV driver in preparation for Unicoap #21907

Are you sure you want to change the base?

drivers/slipmux: Rework SLIPDEV driver in preparation for Unicoap #21907

Conversation

Teufelchen1 commented Nov 21, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Contribution description

Testing procedure

Uh oh!

Teufelchen1 Nov 21, 2025

Choose a reason for hiding this comment

Uh oh!

riot-ci commented Nov 21, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Murdock results

Artifacts

Uh oh!

crasbe left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

crasbe Nov 21, 2025

Choose a reason for hiding this comment

Uh oh!

Teufelchen1 Nov 24, 2025

Choose a reason for hiding this comment

Uh oh!

Teufelchen1 commented Nov 24, 2025

Uh oh!

Uh oh!

Uh oh!

Teufelchen1 commented Nov 24, 2025

Uh oh!

crasbe commented Nov 24, 2025

Uh oh!

mguetschow left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

mguetschow Nov 26, 2025

Choose a reason for hiding this comment

Uh oh!

Teufelchen1 Nov 27, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

mguetschow Nov 26, 2025

Choose a reason for hiding this comment

Uh oh!

mguetschow left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

mguetschow Nov 26, 2025

Choose a reason for hiding this comment

Uh oh!

mguetschow commented Nov 26, 2025

Uh oh!

Teufelchen1 commented Nov 27, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Teufelchen1 commented Nov 21, 2025 •

edited

Loading

riot-ci commented Nov 21, 2025 •

edited

Loading