sys: make auto init default with DHCPv6 client

[OlegHahm]

Contribution description

The DHCPv6 client uses an event queue that needs to get initialized. The auto_init code does that and, hence, should be used by default.

Testing procedure

Build the gnrc_networking example with DHCPv6 client support:

USEMODULE=gnrc_dhcpv6_client make -C examples/gnrc_networking all term

Result

2025-01-30 23:50:21,735 # All up, running the shell now
> 2025-01-30 23:50:22,631 # sys/event/event.c:39 => *** RIOT kernel panic:
2025-01-30 23:50:22,632 # FAILED ASSERTION.
2025-01-30 23:50:22,632 # 
2025-01-30 23:50:22,633 # 	pid | name                 | state    Q | pri | stack  ( used) ( free) | base addr  | current     
2025-01-30 23:50:22,634 # 	 - | isr_stack            | -        - |   - |   8192 (   -1) ( 8193) |  0x80898e0 |  0x80898e0
2025-01-30 23:50:22,634 # 	 1 | idle                 | pending  Q |  15 |   8192 (  436) ( 7756) |  0x80842e0 |  0x808613c 
2025-01-30 23:50:22,635 # 	 2 | main                 | running  Q |   7 |  12288 ( 1664) (10624) |  0x80862e0 |  0x808913c 
2025-01-30 23:50:22,635 # 	 3 | pktdump              | bl rx    _ |   6 |  12224 (  896) (11328) |  0x8091f80 |  0x8094d9c 
2025-01-30 23:50:22,636 # 	 4 | ipv6                 | bl rx    _ |   4 |   8128 ( 1776) ( 6352) |  0x808c1c0 |  0x808dfdc 
2025-01-30 23:50:22,636 # 	 5 | udp                  | bl rx    _ |   5 |   4032 (  960) ( 3072) |  0x8097220 |  0x809803c 
2025-01-30 23:50:22,637 # 	 6 | gnrc_netdev_tap      | bl anyfl _ |   2 |   8064 ( 2264) ( 5800) |  0x808e760 |  0x809053c 
2025-01-30 23:50:22,637 # 	 7 | RPL                  | bl rx    _ |   5 |   8192 (  896) ( 7296) |  0x80951c0 |  0x809701c 
2025-01-30 23:50:22,637 # 	   | SUM                  |            |     |  69312 ( 8892) (60420)
2025-01-30 23:50:22,638 # 
2025-01-30 23:50:22,638 # *** halted.

Expected result
DHCP client works, RIOT doesn't crash.

[riot-ci]

Murdock results

✔️ PASSED

9201073 sys: net: gnrc: set simple_pd specific dhcpv6 hook

Success	Failures	Total	Runtime
10271	0	10271	10m:40s

Artifacts

• Documentation preview

[miri64]

tests/net/gnrc_dhcpv6_client_6lbr needs a DISABLE_MODULE for this test, I think.

[benpicco]

examples/gnrc_border_router too if you set UPLINK=ethernet - which makes me wonder if this is the right thing to do.
We also don't default to including auto_init_gnrc_netif if netdev_default is used.

[miri64]

examples/gnrc_border_router too if you set UPLINK=ethernet

Huh? Why wouldn't you want the DHCPv6 client auto-initialized with Ethernet?

[benpicco]

Why wouldn't you want the DHCPv6 client auto-initialized with Ethernet?

Because gnrc_dhcpv6_client_simple_pd already takes care of it

/home/benpicco/dev/RIOT/sys/net/gnrc/application_layer/dhcpv6/client_simple_pd.c:28:2: error: #error "Module `gnrc_dhcpv6_client_simple_pd` is mutually exclusive to `auto_init_dhcpv6_client`"
   28 | #error "Module `gnrc_dhcpv6_client_simple_pd` is mutually exclusive to \
      |  ^~~~~
make[4]: *** [/home/benpicco/dev/RIOT/Makefile.base:149: /home/benpicco/dev/RIOT/examples/gnrc_border_router/bin/native/gnrc_dhcpv6/client_simple_pd.o] Error 1
make[3]: *** [/home/benpicco/dev/RIOT/Makefile.base:31: ALL--/home/benpicco/dev/RIOT/sys/net/gnrc/application_layer/dhcpv6] Error 2

Maybe add gnrc_dhcpv6_client_simple_ia ?

[OlegHahm]

examples/gnrc_border_router too if you set UPLINK=ethernet - which makes me wonder if this is the right thing to do. We also don't default to including auto_init_gnrc_netif if netdev_default is used.

Because you can use netdev without gnrc.

Isn't it the default for modules any more that the corresponding auto_init is enabled?

[OlegHahm]

I wonder why this error is raised in the C file instead of modelling this check directly in the auto_init().

[OlegHahm]

Wouln't it make sense to consolidate the auto_init code from dhcp6_client with the simple_pd code? There seems to be quite some duplicated code here.

[miri64]

Wouln't it make sense to consolidate the auto_init code from dhcp6_client with the simple_pd code? There seems to be quite some duplicated code here.

They do mainly different configuration, IIRC.

[OlegHahm]

I'll come up with a consolidation proposal.

[OlegHahm]

I moved the former simple_pd init code into the regular auto_init code.

[OlegHahm]

I reverted my previous idea because it was leaking gnrc code into the generic DHCPv6 client code. This new proposal now solves this via a generic hook that can be set during auto_init and is used by the gnrc simple_pd module.