Stm32 + bare-metal + lwip + interrupt

Thank you for the informations.

For me it seems like without an RTOS you can just use the Stack by providing a polling mechanism in the mainloop.

Is is correct that the critical part is to provide a "time base" to the stack by calling sys_check_timeouts() function periodically?

I try to figure out if i can check the packages in the interrupt routine, but after some time when i try to ping the interrupt doesn't occur anymore.

Thank you a lot for the provided solution, i will try it out. Can you explain why it is not the best resource usage to call it each time after a package receive?

Currently I'm using the Cube-generated ethernetif.c, which uses 4 forward chained DMA descriptors, each pointing to a buffer of lenght maximum package size. I'm not sure if i understand their code in low_level_init correctly, but it seems like they go through the descriptors that point to buffers with data, but not necessarily through all 4 descriptors. For me that seems correct, or is it necessary to read all 4 descriptors?

len = heth.RxFrameInfos.length;
 buffer = (uint8_t*) heth.RxFrameInfos.buffer;
 
 if (len > 0) {
 /* We allocate a pbuf chain of pbufs from the Lwip buffer pool */
 p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
 }
 
 if (p != NULL) {
 dmarxdesc = heth.RxFrameInfos.FSRxDesc;
 bufferoffset = 0;
 for (q = p; q != NULL; q = q->next) {
 byteslefttocopy = q->len;
 payloadoffset = 0;
 
 /* Check if the length of bytes to copy in current pbuf is bigger than Rx buffer size*/
 while ((byteslefttocopy + bufferoffset) > ETH_RX_BUF_SIZE) {
 /* Copy data to pbuf */
 memcpy((uint8_t*) ((uint8_t*) q->payload + payloadoffset), (uint8_t*) ((uint8_t*) buffer + bufferoffset),
 (ETH_RX_BUF_SIZE - bufferoffset));
 
 /* Point to next descriptor */
 dmarxdesc = (ETH_DMADescTypeDef*) (dmarxdesc->Buffer2NextDescAddr);
 buffer = (uint8_t*) (dmarxdesc->Buffer1Addr);
 
 byteslefttocopy = byteslefttocopy - (ETH_RX_BUF_SIZE - bufferoffset);
 payloadoffset = payloadoffset + (ETH_RX_BUF_SIZE - bufferoffset);
 bufferoffset = 0;
 }
 /* Copy remaining data in pbuf */
 memcpy((uint8_t*) ((uint8_t*) q->payload + payloadoffset), (uint8_t*) ((uint8_t*) buffer + bufferoffset),
 byteslefttocopy);
 bufferoffset = bufferoffset + byteslefttocopy;
 }
 }