NRF7002-DK and DNS resolver

[Vigen]

Hello,

I've been evaluating the NRF7002-DK with 2.3.0-rc1 SDK. Although there's almost no documentation on how to use Noridc's WiFi stack (at least I haven't found any), the samples in the SDK were great and I was able to get the scanning, connecting and DHCP working just fine.

Where I faced issues was with DNS host resolution using the getaddrinfo API - it just times out regardless the timeout value I put in configuration. I have a feeling this has to do with the configuration, but I wasn't able to figure this out. Attempting to debug the issue cause stack overflow as the library seem to be 'caught' in the middle of static initialization when VScode stops on 'main()' entry.

I would greatly appreciate any help to unblock the use of getaddrinfo() API. Thank you!

Here's what I have in the prj.conf

# WiFi stack.
CONFIG_WIFI=y
CONFIG_WIFI_NRF700X=y
CONFIG_NET_L2_WIFI_MGMT=y
# WPA Supplicant is required to establish WiFi connection.
CONFIG_WPA_SUPP=y

# Networking stack needed for WiFi to operate.
CONFIG_NET_L2_ETHERNET=y
CONFIG_NET_DHCPV4=y
CONFIG_NET_IPV4=y
CONFIG_NET_UDP=y
CONFIG_NET_TCP=y
CONFIG_NET_SOCKETS_POLL_MAX=10
CONFIG_NET_CONFIG_SETTINGS=y
CONFIG_NET_SOCKETS_POSIX_NAMES=y

CONFIG_DNS_RESOLVER=y
CONFIG_DNS_NUM_CONCUR_QUERIES=2
CONFIG_DNS_RESOLVER_LOG_LEVEL_DBG=y
CONFIG_NET_SOCKETS_DNS_TIMEOUT=30000

# SSL?
CONFIG_POSIX_CLOCK=y
CONFIG_ENTROPY_GENERATOR=y

# Buffers.
CONFIG_NET_PKT_RX_COUNT=8
CONFIG_NET_PKT_TX_COUNT=8

# Memories.
CONFIG_NET_TX_STACK_SIZE=4096
CONFIG_NET_RX_STACK_SIZE=4096
CONFIG_NET_MGMT_EVENT_STACK_SIZE=4096

[dejans]

Hi,

Which application or sample do you use? Could you provide more information about your application?

Could you provide log output from your application?

Best regards,
Dejan

[Vigen]

I based my code on sta and scan apps in nrf/samples/wifi. The application scans the available WiFi APs, selects the one that is configured and establishes a WiFi connection with that AP (this part works just fine). Later on the app tries to connect to Azure IoT Hub DPS, which uses getaddrinfo under the hood to resolve the DPS IP address for mqtt to connect to. The Azure connection works just great with NRF9160-DK over LTE, but with NRF7002-DK the DNS resolution fails.

Here's log the log snippet:

[00:00:00.274,902] <inf> wifi_nrf: QSPI freq = 24 MHz
[00:00:00.280,426] <inf> wifi_nrf: QSPI latency = 1
[00:00:00.293,487] <inf> wifi_nrf: wifi_nrf_fmac_fw_load: LMAC patches loaded
[00:00:00.312,042] <inf> wifi_nrf: wifi_nrf_fmac_fw_load: LMAC boot check passed
[00:00:00.322,753] <inf> wifi_nrf: wifi_nrf_fmac_fw_load: UMAC patches loaded
[00:00:00.341,278] <inf> wifi_nrf: wifi_nrf_fmac_fw_load: UMAC boot check passed
[00:00:00.381,652] <inf> wifi_nrf: RPU LPM type: HW
[00:00:00.599,060] <inf> wifi_nrf: wifi_nrf_if_carr_state_chg: Carrier state: 0
[00:00:00.696,716] <dbg> net_dns_resolve: dns_resolve_init_locked: (main): No DNS servers defined.
*** Booting Zephyr OS build v3.2.99-ncs2-rc1 ***
[00:00:00.710,632] <inf> net_config: Initializing network
[00:00:00.716,522] <inf> net_config: Waiting interface 1 (0x20001560) to be up...
[00:00:00.724,487] <inf> net_config: Running dhcpv4 client...
[00:00:00.739,990] <inf> work_queues: IO work queue started
[00:00:00.806,457] <inf> wpa_supp: z_wpas_start: 334 Starting wpa_supplicant thread with debug level: 3
[00:00:00.829,162] <inf> wpa_supp: Successfully initialized wpa_supplicant
[00:00:00.853,759] <inf> wifi: Scanning for WiFi networks
[00:00:00.869,110] <inf> wpa_supp: l2_packet_init: iface wlan0 ifindex 1
[00:00:05.189,361] <inf> wifi: Got WiFi result: ssid=****, security=OPEN, band=5GHz, channel=A1, mac=***
[00:00:05.201,049] <inf> wifi: Got WiFi result: ssid=****, security=OPEN, band=2.4GHz, channel=06, mac=***
[00:00:05.213,958] <inf> wifi: Got WiFi result: ssid=****, security=WPA2-PSK, band=5GHz, channel=95, mac=***
[00:00:05.225,891] <inf> wifi: Got WiFi result: ssid=****, security=WPA2-PSK, band=5GHz, channel=95, mac=***
[00:00:05.238,433] <inf> wifi: Got WiFi result: ssid=****, security=WPA2-PSK, band=2.4GHz, channel=06, mac=***
[00:00:05.250,640] <inf> wifi: Got WiFi result: ssid=****, security=WPA2-PSK, band=2.4GHz, channel=06, mac=***
[00:00:05.263,732] <inf> wifi: Got WiFi result: ssid=****, security=OPEN, band=2.4GHz, channel=01, mac=***
[00:00:05.276,245] <inf> wifi: Got WiFi result: ssid=****, security=WPA2-PSK, band=2.4GHz, channel=0B, mac=***
[00:00:05.288,543] <inf> wifi: Got WiFi result: ssid=****, security=WPA2-PSK, band=5GHz, channel=99, mac=***
[00:00:05.300,811] <inf> wifi: Connecting to ****...
[00:00:10.886,291] <inf> wpa_supp: wlan0: SME: Trying to authenticate with 08:9b:f1:93:36:71 (SSID='****' freq=5240 MHz)
[00:00:10.903,442] <inf> wifi_nrf: wifi_nrf_wpa_supp_authenticate:Authentication request sent successfully
[00:00:11.167,236] <inf> wpa_supp: wlan0: Trying to associate with 08:9b:f1:93:36:71 (SSID='****' freq=5240 MHz)
[00:00:11.188,903] <inf> wifi_nrf: wifi_nrf_wpa_supp_associate: Association request sent successfully
[00:00:11.211,059] <inf> wifi_nrf: wifi_nrf_if_carr_state_chg: Carrier state: 1
[00:00:11.223,602] <inf> wpa_supp: wpa_drv_zep_get_ssid: SSID size: 13
[00:00:11.230,834] <inf> wpa_supp: wlan0: Associated with 08:9b:f1:93:36:71
[00:00:11.238,311] <inf> wpa_supp: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0
[00:00:11.248,657] <inf> wpa_supp: wpa_drv_zep_get_ssid: SSID size: 13
[00:00:11.280,426] <inf> wpa_supp: wlan0: WPA: Key negotiation completed with 08:9b:f1:93:36:71 [PTK=CCMP GTK=CCMP]
[00:00:11.291,564] <inf> wpa_supp: wlan0: CTRL-EVENT-CONNECTED - Connection to 08:9b:f1:93:36:71 completed [id=0 id_str=]
[00:00:11.309,356] <wrn> wifi: Unexpected event received: -536608759
[00:00:11.323,364] <inf> wifi: Connected to WiFi network, waiting for dhcp allocation...
[00:00:12.515,899] <inf> net_dhcpv4: Received: 192.168.12.20
[00:00:12.522,125] <inf> net_config: IPv4 address: 192.168.12.20
[00:00:12.528,503] <inf> net_config: Lease time: 14092 seconds
[00:00:12.534,759] <inf> net_config: Subnet: 255.255.255.0
[00:00:12.540,679] <inf> net_config: Router: 192.168.12.1
[00:00:12.549,072] <inf> wifi: DHCP IP address: 192.168.12.20
[00:00:12.556,304] <dbg> net_dns_resolve: dns_resolve_name: (): DNS id will be 20441
[00:00:12.564,575] <dbg> net_dns_resolve: dns_write: (): [0] submitting work to server idx 0 for id 20441 hash 59079
[00:00:14.564,666] <dbg> net_dns_resolve: query_timeout: (sysworkq): Query timeout DNS req 20441 type 1 hash 59079
[00:00:14.575,408] <dbg> net_dns_resolve: dns_resolve_cancel_with_hash: (sysworkq): Cancelling DNS req 20441 (name google.com type 1 hash 59079)
[00:00:14.588,867] <err> wifi: getaddrinfo failed -101
[00:00:14.594,726] <err> wifi: Failed to resolve www.google.com: -5
[00:00:14.601,684] <err> main: Failed to enable cloud
[00:00:14.607,421] <inf> wifi: Connected to wifi: addrs=192.168.12.1
[00:00:14.614,227] <inf> azure_iot: Initializing Azure IoT Hub...
[00:00:14.621,032] <inf> azure_iot: Azure provisioning not started
[00:00:14.627,868] <dbg> net_dns_resolve: dns_resolve_name: (): DNS id will be 19812
[00:00:14.636,108] <dbg> net_dns_resolve: dns_write: (): [0] submitting work to server idx 0 for id 19812 hash 36583
[00:00:14.729,003] <err> mqtt_helper: mqtt_connect, error: -23
[00:00:14.735,626] <err> azure_iot_hub_dps: mqtt_helper_connect failed, error: -23
[00:00:14.743,835] <err> azure_iot: Failed to start Azure device provisioning: err=-23
[00:00:14.752,441] <err> main: Failed to initialize cloud: err=-23

[dejans]

Hi,

In order to get more information about potential configuration problem, you could try MQTT sample which can run on both nRF9160-DK and nRF7002-DK.

Best regards,
Dejan

[Kenta]

Hello.

There is an application called sample/net/dns_resolve in the Zephyr OS directory.

If you use dns_get_addr_info called in the do_ipv4_lookup function on that side, I think that DNS name resolution will be possible.

Best Regards.

[Vigen]

I've tried the mqtt application and (after updating the prj.conf with my wifi info) got exactly the same result (logs below).

UPDATE: I've also tried the dns_resolve app, but that requires first setting up the wifi on nrf7002 which essentially boils down to the mqtt application.

[00:00:01.673,858] <wrn> wifi_credentials: Cannot retrieve WiFi credentials, no entry found for the provided SSID
[00:00:01.673,919] <inf> wifi_mgmt_ext: Adding statically configured WiFi network [***] to internal list.
[00:00:07.206,115] <inf> network: Wi-Fi Connected
[00:00:14.208,770] <err> mqtt_helper: getaddrinfo() failed, error -101
[00:00:14.208,801] <err> transport: Failed connecting to MQTT, error code: 101

[dejans]

Hi,

With regard to the MQTT sample, I have tested it with additional configuration (which was initially provided) added to the prj.conf. I used nRF7002-DK and NCS v2.3.0-rc1. I could not reproduce the issue with getaddrinfo(). In addition to your changes, I had to add several configuration options (which are shown below) to prj.conf.

CONFIG_WIFI_CREDENTIALS_STATIC=y
CONFIG_WIFI_CREDENTIALS_STATIC_SSID="YourAccesPointSSID"
CONFIG_WIFI_CREDENTIALS_STATIC_PASSWORD="YourPassword"

Best regards,
Dejan

[Vigen]

I think I was finally able to pin-point the problem... My WiFi network is built on Eero Pro Wifi mesh that runs on both 2.4GHZ and 5GHZ frequencies. The DNS resolution works perfectly fine if I disable the 5GHZ band and stops working if both bands are enabled. I've tried to force the band in struct wifi_connect_req_params::band field and setting it to WIFI_FREQ_BAND_2_4_GHZ before connecting with both bands enabled on the WiFi, but the DNS resolution still didn't work.

My understanding was the NRF7002 chip supports WiFi 6 and supposed to work on both bands, but the SDK seems to be under development still - is this something Nordic team is still working on?

[dejans]

Hi,

What is the result if you disable 2.4 GHz band and enable 5 GHz band? 

Could you try Wi-Fi Shell sample when only one, or both of the bands are enabled? What is the result when you run two commands shown below?

net dns <hostname>
net ping <resolved hostname>

Best regards,
Dejan

[Vigen]

I tried with the wifi shell app, and the results are similar to what I experienced with my code (need to run wifi connect <ssid> 0 <psk> before running the commands you've suggested):

2.4GHZ network

uart:~$ net dns www.google.com
Query for 'www.google.com' sent.
dns: 142.250.72.164
dns: All results received
uart:~$ net ping  142.250.72.164
PING 142.250.72.164
28 bytes from 142.250.72.164 to 192.168.0.203: icmp_seq=0 ttl=59 time=42 ms
28 bytes from 142.250.72.164 to 192.168.0.203: icmp_seq=1 ttl=59 time=35 ms
28 bytes from 142.250.72.164 to 192.168.0.203: icmp_seq=2 ttl=59 time=43 ms

Mixed 2.4GHZ+5GHZ network

uart:~$ net dns www.google.com
Query for 'www.google.com' sent.
dns: Timeout while resolving name.

[dejans]

Hi,

dejans said:

What is the result if you disable 2.4 GHz band and enable 5 GHz band? 

Could you provide the result on 5 GHz?

Best regards,
Dejan

[Vigen]

I did several runs, and they were quite inconsistent. Most of the times DNS would work, but from now and then it would timeout, especially on the hosts that are not accessed often. That said, the consequent run on the same host would succeed. I tried to increase the timeout without no effect on resolution error rate, but then I added a retry logic... and now it works like a charm in my app.

Correctly if I am wrong, but with the config I have it the DNS resolution happens over UDP. Then the only explanation I can think of that would induce the above behavior is that sometimes the first packet is lost (radio issues or my wifi setup, can't say), but afterwards things start to work neetly. Here's the log with socket debug enabled:

[00:00:10.627,838] <inf> wifi: Connected to WiFi network, waiting for dhcp allocation...
[00:00:10.975,097] <inf> net_dhcpv4: Received: 192.168.6.57
[00:00:10.975,280] <inf> net_config: IPv4 address: 192.168.6.57
[00:00:10.975,280] <inf> net_config: Lease time: 11120 seconds
[00:00:10.975,341] <inf> net_config: Subnet: 255.255.252.0
[00:00:10.975,433] <inf> net_config: Router: 192.168.4.1
[00:00:10.976,623] <inf> wifi: DHCP IP address: 192.168.6.57
[00:00:12.979,064] <wrn> wifi: Failed to resolve www.google.com: err=-5
[00:00:13.514,526] <inf> wifi: Successfully resolved www.google.com
[00:00:13.531,677] <inf> wifi: Successfully resolved www.amazon.com
[00:00:13.550,781] <inf> wifi: Successfully resolved www.yahoo.com
[00:00:13.550,781] <inf> wifi: All test servers has been successfully resolved

[dejans]

Hi,

Previously, you got timeout when both 2.4 GHz and 5 GHz network bands were enabled. With the addition of your retry logic, do you get successful resolution when both network bands are enabled?

Best regards,
Dejan