Hello,

Could somebody point me an example of sending and receiving simple UDP packets with uIP?. I want to establish a UDP communication between a computer and a PCB.
Thanks in advance,

Hello again,

Thx a lot for your suggestion and help,

I just tried printing "uip_flags & UIP_NEWDATA" and uip_len when the error message is printed, in the uip.c

uip_flags & UIP_NEWDATA is 0
uip_len is 54

meaning that there is no data available for the application
the code is this:




#ifndef __UDPAPP_H__
#define __UDPAPP_H__

#include "pt.h"

typedef struct socket_app_state {
  char name;
} uip_tcp_appstate_t;

void dummy_app_appcall(void);
#ifndef UIP_APPCALL
#define UIP_APPCALL dummy_app_appcall
#endif /* UIP_APPCALL */

typedef struct udpapp_state {
    struct pt pt;
    char state;
    char inputbuf[10];
} uip_udp_appstate_t;


void udp_init(void);
void udpapp_appcall(void);
#ifndef UIP_UDP_APPCALL
#define UIP_UDP_APPCALL udpapp_appcall
#endif /* UIP_UDP_APPCALL */

void udpapp_init(void);

#endif /* __UDPAPP_H__ */




*********************************************************************************************************************************************

#include "uip.h"
#include <string.h>
#include "udp.h"


#define STATE_INIT                0
#define STATE_LISTENING         1
#define STATE_HELLO_RECEIVED    2
#define STATE_NAME_RECEIVED        3

static struct udpapp_state s;

void dummy_app_appcall(void)
{
}

void udp_init(void)
{
    uip_ipaddr_t addr;
    struct uip_udp_conn *c;
   
    uip_listen(HTONS(1167)); the local port
    uip_ipaddr(&addr, 192,168,0,1);  the server where to send UDP
    c = uip_udp_new(&addr, HTONS(9988)); the server port
    if(c != NULL) {
        uip_udp_bind(c, HTONS(1167));
   
    }

    s.state = STATE_INIT;

    PT_INIT(&s.pt);
}

static unsigned char parse_msg(void)
{
    if (memcmp(uip_appdata, "Hello", 5) == 0) {
        return 1;
    }

    return 0;
}

static void send_request(void)
{
    char str[] = "Hello. What is your name?\n";

    memcpy(uip_appdata, str, strlen(str));
    uip_send(uip_appdata, strlen(str));
}

static void send_response(void)
{
    int i = 0;
    char str[] = "Hello ";

    while ( ( ((char*)uip_appdata)[i] != '\n') && i < 9) {
        s.inputbuf[i] = ((char*)uip_appdata)[i];
        i++;
    }
    s.inputbuf[i] = '\n';

    memcpy(uip_appdata, str, 6);
    memcpy(uip_appdata+6, s.inputbuf, i+1);
    uip_send(uip_appdata, i+7);
}

static PT_THREAD(handle_connection(void))
{
    PT_BEGIN(&s.pt);

    s.state = STATE_LISTENING;

    do {
       
        PT_WAIT_UNTIL(&s.pt, uip_newdata());
       
        if(uip_newdata() && parse_msg()) {
           
            s.state = STATE_HELLO_RECEIVED;
            uip_flags &= (~UIP_NEWDATA);
            break;
        }
    } while(s.state != STATE_HELLO_RECEIVED);

    do {
        send_request();
        PT_WAIT_UNTIL(&s.pt, uip_newdata());

        if(uip_newdata()) {
            s.state = STATE_NAME_RECEIVED;
            uip_flags &= (~UIP_NEWDATA);
            break;
        }
    } while(s.state != STATE_NAME_RECEIVED);

    send_response();

    s.state = STATE_INIT;

    PT_END(&s.pt);
}

void udpapp_appcall(void)
{
    handle_connection();
   
}






the main is just the  main in the unix folder when you download uIP, changed to call the udp_init, that's it.

Hope this helps, there are no more changes. Thanks again and I hope you can help me,

Hello Peter,

----- Original Message -----

From: Edgardo C.

To: Peter Zuidema

Cc: uip-users <at> sics.se

Sent: Monday, June 27, 2011 5:36 PM

Subject: Re: [uip-users] UDP problems with IP header

Hello Peter,

First of all, let me say that I am compiling both, the uip UDP application and the pc application on a Linux pc. So, the application that send the UDP datagrams is a GUI application running on the Linux machine where the uip run as well. So, both application run on the same machine.

I removed the uip_listen and the problem persist. I do not receive any packet and what is weird is that even though I don't send any packet from the application, as soon as I run the uip UDP aplication, it gives me the error. I tried compiling the httpd application that comes into the uip package and I get the same error. agrrrrrrrrrrrrrrrrrrrrr

I have no idea.

2011/6/27 Peter Zuidema <pzuidema <at> opencontroller.com>

Hello Edgardo,

Remove the uip_listen() call because this is only for TCP.

Do you receive nothing at all (the 1st Hello), or do you see the error after waiting for response after send_request()?

In the last case, try resetting the newdata flag directly after send_request().

Regards,
Peter

Hello Peter and Martin,

Hello, I am here again,