[lwip-users] TCP transmission problem (raw API callback function)

[Bessone Danilo]

Hello,

I have observed that the callback function(raw API interface)specified by tcp_sent()is erroneously called when a TCP packet is received with the ACK flag set and the ackno value (TCP header) does not acknowledges new data and differs from pcb->lastack. In this case pcb->acked is not cleared as expected by the tcp_receive() function and the callback function is erroneously called from the tcp_process() function if the "old, not updated" pcb->acked value differs from zero. As conseguence the application program computes a total number of acknowledged bytes that is greater than the total number of transmitted data bytes.

I have found that if the code "pcb->acked = 0" is inserted at the beginning of the tcp_receive() function this problem disappears.

 

Regards

Danilo Bessone

 

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