Re: [lwip-users] Role of tcpip_thread when LWIP_TCPIP_CORE_LOCKING is enabled

[Simon Goldschmidt]

Hi,

in your configuration, tcpip_thread only does little work but is still required. It handles timers, delayed writes etc. You won't notice missing it right away, but you'll still need it eventually.

Regards,
Simon

Am 24. Dezember 2024 02:13:03 MEZ schrieb kyle shim <kyle.s.shim@gmail.com>:

Hi guys,

I'm experimenting with lwip in linux environment with pcap library. I added socket API applications to my program. I wonder what role tcpip_thread does in my environment.

I configured the following three options as below and lwip is initialized with tcpip_init().

#define NO_SYS                                        0
#define LWIP_TCPIP_CORE_LOCKING     1
#define LWIP_SOCKET                             1

The application structure is similar to the below diagram except for "Ethernet ISR". "Network Interface Task" waits for network frames from pcap library.

Application is using socket APIs and it's communicating with lwip via mbox defined for linux environment. But I found that "Network Interface Task" process TCP level jobs and it interacts with socket application. mbox(static sys_mbox_t tcpip_mbox) in tcpip_thread is not used at all. Even when I commented out the line where tcpip_thread is created, lwip with socket applications works fine.

// sys_thread_new(TCPIP_THREAD_NAME, tcpip_thread, NULL, TCPIP_THREAD_STACKSIZE, TCPIP_THREAD_PRIO);

Am I missing something? What is the role of tcpip thread in this environment?

Thanks guys.
Kyle