UDP Tx partial fail when using Lwip within uC/OS

hi all!

I was trying to send a UDP packet using conn_send(). However, I find that when I use netbuf_ref() to send data which the ptr points to, what I got in the reciever side was not the data ptr point to. But is was OK if I'm using netbuf_alloc() to send some immediate data.

Another thing that I can't understand is whichever buffer or data structure the ptr points to, when using netbuf_ref(), the data sent on the physical wire is always the same!

Here's my code:

void udp_task()

{

struct netconn *conn;

struct netbuf* buf;

struct ip_addr udpDestIpAddr,udpLocalIpAddr;

u8_t test[10];

int i;

u8_t *data;

void *ptr;

for(i=0;i<10;i++){

test=i;

}

ptr = test;

conn = netconn_new(netconn_udp);

ip4_addr(&udpdestipaddr, 10, 1, 1, 15);

ip4_addr(&udplocalipaddr, 10, 1,1, 19);

printf("udp_init\n");

netconn_bind(conn,&udplocalipaddr,38);

netconn_connect(conn,&udpdestipaddr,10);

while(1)

{

buf = netbuf_new();

data = netbuf_alloc(buf,10);

for(i=0;i<10;i++)

data=i;

netconn_send(conn, buf);

//""this command function just the way it is, and I recieve exactly what I sent ""

netbuf_ref(buf,&test[0],10);

netconn_send(conn, buf);

//""here is where everything goes wrong, I recieved the wrong data""

netbuf_ref(buf,&test[0]+10,10);

netconn_send(conn, buf);

/*""I recieved exactly the same fault data just like above, it seems the pointer has *no effect of determining which data should be sent""

*/

OSTimeDlyHMSM(0, 0, 3, 0);

printf("udp sent ");

netbuf_delete(buf);

}

}

Thanks in advance!