cannot connect to lwip binded socket address after idle for sometime - sockets

Question

I am using lwIP under FreeRTOS, the IP server runs on an ARM based device (Xilinx Zynq-7020) and the client is a windows.
At the server side, when I bind, listen, and accept an address:port, the client can connect to and read/write from this address. And after program exit, idle for some short time (10s~30s) then start again, it can also read/write from the server. Howeber, when I exit the client, and idle for a long time (>30s), I cannot connect to the server anymore. And at the server side, it no longer accept any address. Any solutions ?
The code for the server side is listed below:
void echo_server( void *pvParameters )
{
long lSocket, lClientFd, lAddrLen = sizeof( struct sockaddr_in );
struct sockaddr_in sLocalAddr;
struct sockaddr_in client_addr;
static char dIn[BUF_SIZE];
int ret;
( void ) pvParameters;
int on = 1;
int idle = 60;
int intvl = 15;
int cnt = 3;
/* step 1. create and setopts */
lSocket = lwip_socket(AF_INET, SOCK_STREAM, 0);
if( lSocket >= 0 )
{
lwip_setsockopt(lSocket, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on));
//lwip_setsockopt(lSocket, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle));
//lwip_setsockopt(lSocket, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl));
//lwip_setsockopt(lSocket, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt));
memset((char *)&sLocalAddr, 0, sizeof(sLocalAddr));
// prepare bind on port
sLocalAddr.sin_family = AF_INET;
sLocalAddr.sin_len = sizeof(sLocalAddr);
sLocalAddr.sin_addr.s_addr = htonl(INADDR_ANY);
sLocalAddr.sin_port = ntohs( ( ( unsigned short ) ECHO_PORT ) );
/* step 2. bind */
if( lwip_bind( lSocket, ( struct sockaddr *) &sLocalAddr, sizeof( sLocalAddr ) ) < 0 )
{
lwip_close( lSocket );
vTaskDelete( NULL );
}
/* step 3. listen */
if( lwip_listen( lSocket, BACKLOG ) != 0 )
{
lwip_close( lSocket );
vTaskDelete( NULL );
}
for( ;; )
{
/* step 4. accept */
xil_printf("(ZYNQ-ECH) wait connection\n");
lClientFd = lwip_accept(lSocket, ( struct sockaddr * ) &client_addr, ( u32_t * ) &lAddrLen );
xil_printf("(ZYNQ-ECH) accept connection\n");
lwip_setsockopt(lClientFd, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on));
//lwip_setsockopt(lClientFd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle));
//lwip_setsockopt(lClientFd, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl));
//lwip_setsockopt(lClientFd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt));
// if client socket created
if( lClientFd > 0L )
{
int packet = 0;
while(1)
{
ret = mfeit_read(lClientFd, dIn);
if (ret == -1 || ret == 0)
break;
ret = mfeit_write( lClientFd, dIn, ret );
if (ret == -1 || ret == 0)
break;
packet ++;
}
xil_printf("(ZYNQ-ECH) close connection, total = %d\n", packet);
lwip_close( lClientFd );
}
}
}
/* Will only get here if a listening socket could not be created. */
xil_printf("(ZYNQ-ECH) task killed !!\n");
vTaskDelete( NULL );
}

Answer 1

I forgot about that stuff, but first you need to set up proper way of keep-alive.
is keep-alive on server configured, so for how long he is persisting keep-alive
set proper time for keep-alive on your side.
Don't do keep-alive with 2hrs or someting. Create a new socket for that it's bad for server resources.