How to create chain of pbuf's to be sent? Send data using UDP.

[profprogrammer]

How to creat and initsializtion this struct for send data using UDP

struct pbuf *p;

I using this code.   

struct netif fsl_netif0;  struct udp_pcb * pcb;  ip_addr_t fsl_netif0_ipaddr, fsl_netif0_netmask, fsl_netif0_gw;     #define PORT_M 9000    void eth_lwip_init () {        lwip_init();       IP4_ADDR(&fsl_netif0_ipaddr, 192,168,70,110);    IP4_ADDR(&fsl_netif0_netmask, 255,255,255,0);    IP4_ADDR(&fsl_netif0_gw, 192,168,70,1);    netif_add(&fsl_netif0, &fsl_netif0_ipaddr, &fsl_netif0_netmask, &fsl_netif0_gw, NULL, ethernetif_init, ethernet_input);       netif_set_default(&fsl_netif0);       {     uint32_t dt = 0;     ENET->MSCR = 0x26<<1;     PHY_DRV_Read (0,0,0x1f, &dt);     dt |= (1<<7);     PHY_DRV_Write (0, 0, 0x1f, dt );     OSA_TimeDelay(1000);    }           // get new pcb      pcb = udp_new();      if (pcb == NULL) {          LWIP_DEBUGF(UDP_DEBUG, ("udp_new failed!\n"));          return;      }          //bind to any IP address on port  //IP_ADDR_ANY      if (udp_bind(pcb, &fsl_netif0_ipaddr, PORT_M) != ERR_OK) {          LWIP_DEBUGF(UDP_DEBUG, ("udp_bind failed!\n"));          return;      }         netif_set_up(&fsl_netif0);      // set udp_echo_recv() as callback function      // for received packets      udp_recv(pcb, udp_echo_recv, NULL);           ///  test message      {   uint8_t i;      err_t err_if;         struct pbuf *p;         struct udp_hdr* u_hdr;        // extern struct udp_pcb *pcb;         uint8_t data[8] = {0x55, 0x44, 0x33, 0x22, 0x11, 0x0, 0x0, 0x0 };            p = pbuf_alloc(PBUF_TRANSPORT, 8, PBUF_RAM);            u_hdr = (struct udp_hdr *)p->payload;         u_hdr->src=(uint16_t) fsl_netif0_ipaddr;         u_hdr->dest = PORT_M;         u_hdr->len = sizeof(struct udp_hdr) + sizeof(data);            for (i=0; i<sizeof(data); i++) {      ((char*)u_hdr)[sizeof(struct udp_hdr) + i] = (char)data[i];         }            u_hdr->chksum = inet_chksum( &u_hdr, 8UL);         err_if = udp_send ( pcb, p );      if (err_if != ERR_OK) {      printf ("Error udp_sendto = %d\n", err_if);      }        pbuf_free (p);      }  }

How to send data fo udp packets?

[isaacavila]

Hello,

If you look at KSDK 1.3 examples, you will find the lwip_udpecho_demo_freertos_frdmk64f project that echoes udp data.

In this example, you will notice that netconn_send() function is used to send the data over UDP:

/**
 * Send data over a UDP or RAW netconn (that is already connected).
 *
 * @param conn the UDP or RAW netconn over which to send data
 * @param buf a netbuf containing the data to send
 * @return ERR_OK if data was sent, any other err_t on error
 */
err_t
netconn_send(struct netconn *conn, struct netbuf *buf)
{
  struct api_msg msg;
  err_t err;
  LWIP_ERROR("netconn_send: invalid conn",  (conn != NULL), return ERR_ARG;);
  LWIP_DEBUGF(API_LIB_DEBUG, ("netconn_send: sending %"U16_F" bytes\n", buf->p->tot_len));
  msg.function = do_send;
  msg.msg.conn = conn;
  msg.msg.msg.b = buf;
  err = TCPIP_APIMSG(&msg);
  NETCONN_SET_SAFE_ERR(conn, err);
  return err;
}

You only need to use conn pointer as NETCONN_UDP:

static void udpecho_thread(void *arg)
{
    static struct netconn *conn;
    static struct netbuf *buf;
    char buffer[100];
    err_t err;
    LWIP_UNUSED_ARG(arg);
    netif_set_up(&fsl_netif0);
    conn = netconn_new(NETCONN_UDP);
    LWIP_ASSERT("con != NULL", conn != NULL);
    netconn_bind(conn, NULL, 7);
    while (1) 
    {
        err = netconn_recv(conn, &buf);
        if (err == ERR_OK) 
        {
            if(netbuf_copy(buf, buffer, buf->p->tot_len) != buf->p->tot_len) 
            {
                LWIP_DEBUGF(UDPECHO_DBG, ("netbuf_copy failed\r\n"));
            } 
            else 
            {
                buffer[buf->p->tot_len] = '\0';
                err = netconn_send(conn, buf);
                if(err != ERR_OK) 
                {
                LWIP_DEBUGF(UDPECHO_DBG, ("netconn_send failed: %d\r\n", (int)err));
                } 
                else 
                {
                    LWIP_DEBUGF(UDPECHO_DBG, ("got %s\r\n", buffer));
                }
            }
            netbuf_delete(buf);
        }
    }
}

You can also look for udpecho_thread to see how connection is established, receiving and sending data over UDP.

I hope this can help you!

Best Reards,

Isaac

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