cpu/esp*: define esp_now as default netdev

[gschorcht]

Contribution description

For ESP32 and ESP8266 boards, various on-board netdevs can be enabled by the esp-now, esp-wifi, esp-eth pseudo modules.

Since esp-wifi requires additional configuration settings and esp-eth is not available on each board, esp-now is defined as default netdev if none of the other netdev modules is enabled explicitly.

It is possible to use multiple netdevs. GNRC_NETIF_NUMOF is determined automatically as long as dynamic approaches in PR #9903 and #12308 are not available.

Testing procedure

Test the following configurations:

1. esp-now as default netdev

   make BOARD=esp32-wroom-32 -C tests/netstats_l2 flash test
   

   esp-now should be used as default netdev and the statistics should contain a L2-PDU size of 249.

2. esp-wifi as default netdev

   USEMODULE=esp_wifi make BOARD=esp32-wroom-32 -C tests/netstats_l2 flash test
   

   esp-wifi should be used as default netdev and the statistics should contain a L2-PDU size of 1500.

3. esp-eth as default netdev

   USEMODULE=esp_wifi make BOARD=esp32-olimex-evb -C tests/netstats_l2 flash test
   

   Check with command

   grep MODULE_ESP_ETH tests/netstats_l2/bin/esp32-olimex-evb/riotbuild/riotbuild.h
   

   that module esp_eth is used.

4. Multiple netdevs

   USEMODULE='esp_wifi esp_now' make BOARD=esp32-wroom-32 -C tests/netstats_l2 flash term
   

   There should be two netdevs with the ifconfig command.

5. Tests 1, 2 and 3 for esp32-wroom-32 board should also work for esp8266-esp-12x board.

Issues/PRs references

Makes #12756 obsolete

[benpicco]

Works like a charm!
Any reason not to also include this for esp8266?

This is unrelated to this PR, but the esp_now interface doesn't get a link-local address with the gnrc_networking example:

2019-11-23 08:50:36,049 # Iface  9  HWaddr: 3C:71:BF:9E:13:FD 
2019-11-23 08:50:36,053 #           L2-PDU:249 MTU:1280  HL:64  RTR  
2019-11-23 08:50:36,057 #           6LO  Source address length: 6
2019-11-23 08:50:36,059 #           Link type: wireless
2019-11-23 08:50:36,062 #           inet6 group: ff02::2
2019-11-23 08:50:36,064 #           inet6 group: ff02::1
2019-11-23 08:50:36,067 #           inet6 group: ff02::1a
2019-11-23 08:50:36,068 #           
2019-11-23 08:50:36,071 #           Statistics for Layer 2
2019-11-23 08:50:36,074 #             RX packets 0  bytes 0
2019-11-23 08:50:36,078 #             TX packets 0 (Multicast: 0)  bytes 0
2019-11-23 08:50:36,081 #             TX succeeded 0 errors 0
2019-11-23 08:50:36,084 #           Statistics for IPv6
2019-11-23 08:50:36,087 #             RX packets 0  bytes 0
2019-11-23 08:50:36,091 #             TX packets 3 (Multicast: 3)  bytes 144
2019-11-23 08:50:36,094 #             TX succeeded 3 errors 0

[gschorcht]

No reason. Should we rename the PR to cpu/esp* and add the same for ESP8266?

[benpicco]

Sure, go ahead!

[gschorcht]

@benpicco I have added the same for esp8266. Test steps 1, 2, and 4 should also work for any esp8266 board.

[benpicco]

Tested both on esp32 and esp8266, please squash!

Two unrelated things:

• esp8266 prints scandoneevery 10s which is a bit annoying
• no link-local address after boot, but they can communicate after manually assigning an address

[gschorcht]

• esp8266 prints scandoneevery 10s which is a bit annoying

Yes. Sinec ESP-NOW is an ad-hoc network, ESP-NOW nodes scan every 10 seconds for new peers. Unfortunately, these messages come from the depth of the vendor binary blobs and I couldn't figure out til now how to disable them in the ESP8266 RTOS SDK. It's the same with the other messages like

add if0
add if1
bcn 100

I will place it on the open issue list in issue #12707.

• no link-local address after boot, but they can communicate after manually assigning an address

That's clear. tests/netstats_l2 doesn't include IPV6, ICMP and NDP for SLAAC. You
could try

CFLAGS='-DGNRC_IPV6_NIB_CONF_SLAAC=1' make BOARD=esp8266-esp-12x -C examples/gnrc_networking flash test

to get a link local address assigned automatically which works definitely.

[benpicco]

That's clear. tests/netstats_l2 doesn't include IPV6, ICMP and NDP for SLAAC.

Yea it took me a bit but then I noticed there was also a message printed about it:

2019-11-23 14:21:47,979 # SLAAC not activated; will not auto-configure IPv6 address for interface 9.
2019-11-23 14:21:47,983 #     Use GNRC_IPV6_NIB_CONF_SLAAC=1 to activate.

And indeed with -DGNRC_IPV6_NIB_CONF_SLAAC=1 I get the address I expected.
Still this is with examples/gnrc_networking so I would expect this to be enabled - @miri64 is this a bug?

[gschorcht]

Still this is with examples/gnrc_networking so I would expect this to be enabled - @miri64 is this a bug?

ESP-NOW nodes are so-called 6Lo nodes but not 6LN nodes. That is, they use the 6Lo sublayer for fragmentation, but they don't support neighbor discovery according to RFC6775 for the address configuration. The distinction between 6Lo nodes and 6LN nodes was introduced by @miri64 with PR #10499 after a long discussion we had a year ago when esp_now was realized as netdev. As I remember, the reason why ESP-NOW nodes can't be 6LN nodes is that they don't have a unique eui64. But this is something that @miri64 could explain much better than me.

But, indeed the default behavior has changed for ESP-NOW nodes which got a link local address automatically before PR #10499 was merged.

@miri64 Makes it sense to define GNRC_IPV6_NIB_CONF_SLAAC=1 for ESPs if esp_now module is enabled?

[gschorcht]

@benpicco Thanks for reviewing, testing and merging.