[lwip-devel] Help with dns_gethostbyname

[Flavio Castro Alves Filho]

Hello,

I would like to ask some help regarding the use of dns_gethostbyname function.

I am having two errors:

1) There is an error on the execution
2) The function is blocking (according to the documentation, it is
told to be non-blocking).

My hardware setup is a custom board using STM32F417, STM32Cube and
LWIP 2.0.3 with FreeRTOS.

I enabled the DNS debug messages. The messages are below:

2020-11-15 19:16:28 APP-MB-DL-SLAVELIST: File map.cfg size 1107
2020-11-15 19:16:29 NETWORK MANAGER: CHECK
2020-11-15 19:16:29 NETWORK MANAGER: INIT
2020-11-15 19:16:29 NETWORK MANAGER: Ethernet selected
2020-11-15 19:16:29 NETWORK MANAGER: NETWORK_START
2020-11-15 19:16:29 ETH: Starting Ethernet Network Interface
2020-11-15 19:16:29 dns_tmr: dns_check_entries
2020-11-15 19:16:30 dns_tmr: dns_check_entries
2020-11-15 19:16:30 APP-MB-DL-SLAVELIST: Map file opened
2020-11-15 19:16:30 APP-BASE: Modbus map loaded
2020-11-15 19:16:31 ETH: IP: 192.168.100.146
2020-11-15 19:16:31 ETH: Netmask: 255.255.255.0
2020-11-15 19:16:31 ETH: Gateway: 192.168.100.1
2020-11-15 19:16:31 ETH: DNS: 8.8.8.8
2020-11-15 19:16:31 NETWORK MANAGER: STARTED
2020-11-15 19:16:31 dns_tmr: dns_check_entries
2020-11-15 19:16:32 dns_tmr: dns_check_entries
2020-11-15 19:16:33 dns_tmr: dns_check_entries
2020-11-15 19:16:33 APP-BASE: Sending stored files to the server
2020-11-15 19:16:33 CONNECTION MODE: 1
2020-11-15 19:16:33 NETWORK API: Host Connection establishment nb 5
2020-11-15 19:16:33 NETWORK API: Connecting to the host mqtt.tago.io port 1883
2020-11-15 19:16:33 dns_enqueue: "mqtt.tago.io": use DNS entry 0
2020-11-15 19:16:34 dns_tmr: dns_check_entries
2020-11-15 19:16:34 dns_send: dns_servers[0] "mqtt.tago.io": request
2020-11-15 19:16:34 sending DNS request ID 359 for name "mqtt.tago.io"
to server 0
2020-11-15 19:16:34 dns_send returned error: Illegal value.
2020-11-15 19:16:35 dns_tmr: dns_check_entries
2020-11-15 19:16:35 dns_send: dns_servers[0] "mqtt.tago.io": request
2020-11-15 19:16:35 sending DNS request ID 359 for name "mqtt.tago.io"
to server 0
2020-11-15 19:16:35 dns_send returned error: Illegal value.
2020-11-15 19:16:36 dns_tmr: dns_check_entries
2020-11-15 19:16:36 dns_send: dns_servers[0] "mqtt.tago.io": request
2020-11-15 19:16:36 sending DNS request ID 359 for name "mqtt.tago.io"
to server 0
2020-11-15 19:16:36 dns_send returned error: Illegal value.
2020-11-15 19:16:37 dns_tmr: dns_check_entries
2020-11-15 19:16:38 dns_tmr: dns_check_entries
2020-11-15 19:16:38 dns_send: dns_servers[0] "mqtt.tago.io": request
2020-11-15 19:16:38 sending DNS request ID 359 for name "mqtt.tago.io"
to server 0
2020-11-15 19:16:38 dns_send returned error: Illegal value.
2020-11-15 19:16:39 dns_tmr: dns_check_entries
2020-11-15 19:16:40 dns_tmr: dns_check_entries
2020-11-15 19:16:41 dns_tmr: dns_check_entries
2020-11-15 19:16:41 dns_check_entry: "mqtt.tago.io": timeout
2020-11-15 19:16:42 dns_tmr: dns_check_entries
2020-11-15 19:16:43 dns_tmr: dns_check_entries


In my code, the blocked function, when monitoring using breakpoints,
is the function dns_gethostbyname.

The network interface is up, capturing the IP address from DHCP.

Is there any clue about what am I possibly (probably) doing wrong?

Best regards,

Flavio


-- 
Flavio de Castro Alves Filho

flavio.alves@gmail.com
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