Re: [lwip-users] UDP send problem

[Martin Persich]

You have a quite short timeout. Isn't there a problem with ARP address 
resolution for tha first two times ? This may be longer then 100 ms by my 
mind ...
Martin Persich



----- Original Message ----- 
From: "Andrea Visinoni" <address@hidden>
To: "Mailing list for lwIP users" <address@hidden>
Sent: Tuesday, October 12, 2010 11:10 AM
Subject: [lwip-users] UDP send problem


> Hi,
> i just modified a HTTP client example to send an UDP packet to my NTP 
> server. But it works only if i send my packet 3 times, the first 2 send 
> are not working.
> With the HTTP original example it was working correctly since the first 
> write.
> Any hits? I'm using FreeRTOS + lwip 1.3.2 on a AT32UC3A board.
>
> Andrea
>
> portTASK_FUNCTION( vNTP, pvParameters )
> {
> int s, ret, err, opt;
> struct sockaddr_in addr;
> struct tm tm_time;
> time_t timetest;
> unsigned long rxbuf[12];
> char            errs[255];
> unsigned char   msg[48] = {010, 0, 0, 0, 0, 0, 0, 0, 0};    // the packet 
> we send
>
> /* set up address to connect to */
> memset(&addr, 0, sizeof(addr));
> addr.sin_len = sizeof(addr);
> addr.sin_family = AF_INET;
> addr.sin_port = htons(123);
> addr.sin_addr.s_addr = inet_addr("10.0.2.34");
>
> /* create the socket */
> if ((s = lwip_socket(AF_INET, SOCK_DGRAM, 0)) == -1)
> {
> err = errno;
> printk("create socket error, errno: %d\n", err);
> go_idle();
> }
>
> /* connect */
> if ((ret = lwip_connect(s, (struct sockaddr*)&addr, sizeof(addr))) == -1)
> {
> err = errno;
> printk("Connect error, errno: %d\n", err);
> go_idle();
> }
>
> /* set recv timeout (100 ms) */
> opt = 100;
> ret = lwip_setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &opt, sizeof(int));
>
> /* Write data */
> ret = lwip_write(s, (char *)msg, sizeof(msg));
> ret = lwip_write(s, (char *)msg, sizeof(msg));
> ret = lwip_write(s, (char *)msg, sizeof(msg));
>
> /* Read data*/
> ret = lwip_read(s, (char *)rxbuf, 12 * 4);
>
> if (ret == 48)
> {
> timetest  = ntohl((time_t)rxbuf[10]);
> timetest -= 2208988800U;
>
> tm_time = gmtime(&timetest)[0];
>
> sprintf (errs, "time : %02d/%02d/%d %02d:%02d:%02d\n", tm_time.tm_mday, 
> tm_time.tm_mon + 1, tm_time.tm_year + 1900, tm_time.tm_hour, 
> tm_time.tm_min, tm_time.tm_sec);
> printk(errs);
> }
>
> go_idle();
> }
>
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