lwip api build issue

Chris Wilson

Is anyone aware of any issues regarding the use of the lwip api within Starterware?

I have added in some example code (from Design and Implementation of the lwip TCP/IP stack) into a working example project (enetlwip using CCS v5).

I get build errors - first with LWIP_NETCONN not appearing to be set correctly - corrected this, now a whole lot of code appears to throw up errors. Must an api library be built first?

Regards

Chris

Code as follows:

conn = netconn_new(NETCONN_UDP);

// setup the IP address of remote host ipAddress.

addr = htonl(0xC0A80101);

// connect to the remote host on port number 7000

netconn_connect(conn, &ipAddress, 7000);

// create new netbuf

buf = netbuf_new();

data = netbuf_alloc(buf, 10);

// create some data

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

data[i] = i;

// send the data

netconn_send(conn, buf);

// reference the text into the netbuf

netbuf_ref(buf, text, sizeof(text));

// send the text

netconn_send(conn, buf);

// clean up

netconn_delete(conn);

netbuf_delete(buf);

over 13 years ago

0 Jay Larson over 13 years ago

Prodigy 230 points

Hi Cris,

I've not used the netcon API, but I have had success with lwIP's low level interface. I might suggest using it... This code snip from an older post (http://e2e.ti.com/support/embedded/starterware/f/790/t/171893.aspx) may help. It sends a periotic broadcast over udp, so you would use your address in place of the broadcast one. Also, you can delete the ref count code lines which we used for finding a problem in the sitaraif.c driver. Hope this helps.

struct udp_pcb* pcb = udp_new();
struct pbuf *p;
udp_bind(pcb, IP_ADDR_ANY, 1235);
char msg[80];
int packet = 0;

/* Loop forever. All the work is done in interrupt handlers. */
while(1)
{

packet++;
p = pbuf_alloc(PBUF_TRANSPORT, sizeof(msg), PBUF_RAM); // allocate a pbuf, (ref=1)
if (!p || 1!=p->ref)
{
UARTPuts("pbuf_alloc failed!\n", -1);
while (1) ;
}
sprintf(msg, "test packet %d", packet);
memcpy(p->payload, msg, strlen(msg));
UARTprintf("packet %d, PBuf at 0x%08X, ref = %d sending...", packet, p, p->ref);
udp_sendto(pcb, p, IP_ADDR_BROADCAST, 1234);
delay(500); // half second delay - should have plenty of time to send
UARTprintf("ref is now %d \n", p->ref);
pbuf_free(p); // ref should be zero after we free.
}
}

Hope this helps.

Cheers,

-Jay

0 Chris Wilson over 13 years ago in reply to Jay Larson

Intellectual 340 points

Hi Jay

Thanks for the response.

Yes, I have subsequently moved down to the low level LWIP (after more reading it suggested that threading (and therefore an o/s) is required for the netconn system. I abandoned that and have been able to modify the lwip_echo example to do both TCP and UDP echoing as below:

Regards

Chris

//***********************************************************

// UDP receive

//***********************************************************

void udp_receive(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port)

{

udp_connect( pcb, addr, port );

// now echo rec'd data

udp_send( pcb, p );

pbuf_free(p);

}

//***********************************************************

// UDP initialisation - listen

//***********************************************************

void UDP_init(void)

{

struct udp_pcb *pcb;

pcb = udp_new();

udp_bind( pcb, IP_ADDR_ANY, UDP_SERVER_PORT );

// receive callback

udp_recv( pcb, udp_receive, (void*)0 );

}

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