Using the LWIP protocol stack for TCP communication, the device ran as a TCP server for a period of time and found itself stuck in the send interface: send (socket_num, (const void *) msg, len, 0), In addition, after repeated testing, it is easy to reproduce when the device communicates with the PC through the company's internal network (possibly through complex network exchanges, within 1 hour); If the device is directly connected to the PC, it may take a long time to reproduce. What could be the reason for this? The message in case of exception is as follows, but no useful information can be seen:(192.168.1.114 is server)
21190 153.099232 192.168.2.114 192.168.2.36 TCP 79 8080 → 11549 [PSH, ACK] Seq=38152 Ack=10695 Win=2062 Len=25 [TCP segment of a reassembled PDU] 21191 153.099397 192.168.2.36 192.168.2.114 TCP 60 11549 → 8080 [PSH, ACK] Seq=10695 Ack=38177 Win=64010 Len=6 21192 153.105834 192.168.2.114 192.168.2.36 TCP 60 8080 → 11549 [ACK] Seq=38177 Ack=10701 Win=2056 Len=0 21193 153.106100 192.168.2.114 192.168.2.36 TCP 79 8080 → 11549 [PSH, ACK] Seq=38177 Ack=10701 Win=2056 Len=25 [TCP segment of a reassembled PDU] 21194 153.106194 192.168.2.36 192.168.2.114 TCP 60 11549 → 8080 [PSH, ACK] Seq=10701 Ack=38202 Win=63985 Len=6 21201 153.319122 192.168.2.36 192.168.2.114 TCP 60 [TCP Retransmission] 11549 → 8080 [PSH, ACK] Seq=10701 Ack=38202 Win=63985 Len=6 21211 153.620255 192.168.2.36 192.168.2.114 TCP 60 [TCP Retransmission] 11549 → 8080 [PSH, ACK] Seq=10701 Ack=38202 Win=63985 Len=6 