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Id:: icmp-udp.c 3538 2011-08-10 16:34:10Z haraldkipp

This sample demonstrates the icmp error handling for udp sockets. NUT_UDP_ICMP_SUPPORT has to be enabled in the configurator to use icmp support on UDP sockets.

Connect the RS232 port of the Ethernut with a free COM port of your PC and run a terminal emulator at 115200 Baud.

Configure MY_IP, MY_MASK, and MY_GATE approriate. Configure UDP_ECHO_IP to the IP of a host running an udp echo server.

The program will try to send some UDP packets to the given destination address on port 7 (UDP echo port) and will try to read back the sended data.

You can run the udp_echo java program in this directory with admin (root) priviledges to have a simple udp echo server on your pc.

Just start the program with 'java udp_echo.class' This program will echo back every data packet received on udp port 7. The program can be stoped with <ctrl>+

If the udp_echo program (or any other udp echo server) is not running you'll receive ICMP destination unreachable messages. Which will be noticed from this demo app on the next send or receive call.


#define MY_MAC          {0x00,0x06,0x98,0x20,0x00,0x00}
#define MY_IP           "192.168.1.100"
#define MY_MASK         "255.255.255.0"
#define MY_GATE         "192.168.1.254"

#define UDP_ECHO_IP     "192.168.1.103"
#define UDP_ECHO_PORT   7

#include <string.h>
#include <stdio.h>
#include <io.h>
//#include <inttypes.h>
#include <errno.h>

#include <dev/board.h>

#include <sys/thread.h>
#include <sys/timer.h>
#include <sys/socket.h>
#include <sys/confnet.h>

#include <arpa/inet.h>
#include <net/route.h>

#define UDP_BUFF_SIZE 256

static char send_buffer[UDP_BUFF_SIZE];
static char rcv_buffer[UDP_BUFF_SIZE];
static uint8_t my_mac[] = MY_MAC;

#ifdef DEV_ETHER

/* Print error message */
void print_udp_icmp_error(uint32_t remote_ip, uint16_t remote_port, int error)
{
    printf("ICMP destination unreachable received for remote ip: %s\r\nremote port: %d, errno: %d -- ", 
           inet_ntoa(remote_ip), remote_port, error);
    
    switch (error) {
        case ENETUNREACH:
            printf("Destination network unreachable\r\n");
            break;
        case EHOSTUNREACH:
            printf("Destination host unreachable\r\n");
            break;
        case ENOPROTOOPT:
            printf("Destination protocol unreachable\r\n");
            break;
        case ECONNREFUSED:      
            printf("Destination port unreachable / connection refused\r\n");
            break;
        case EMSGSIZE:
            printf("Fragmentation required, and DF flag set\r\n");
            break;
        case EOPNOTSUPP:
            printf("Source route failed\r\n");
            break;
        case EHOSTDOWN:
            printf("Destination host unknown or down\r\n");
            break;
        default:
            printf("Other error\r\n");
    }
}

THREAD(UDPReceiver, arg)
{
    uint32_t remote_ip;
    uint16_t remote_port;
    UDPSOCKET *socket = (UDPSOCKET*) arg;
    int      rc;
    
    while (1) {
        rc = NutUdpReceiveFrom(socket, &remote_ip, &remote_port, rcv_buffer, UDP_BUFF_SIZE, 2000);
        if (rc == 0) {
            printf("<-- Timeout (2 sec.) on UDP receive\r\n");
        } else 
        if (rc < 0) {
#ifdef NUT_UDP_ICMP_SUPPORT             
            int error;
            error = NutUdpError(socket, &remote_ip, &remote_port);
            print_udp_icmp_error(remote_ip, remote_port, error);
#endif            
        } else {
            printf("<-- Received packet: \"%s\"\r\n", rcv_buffer);
        }
    }
}

#endif /* DEV_ETHER */

/*
 * Main application routine. 
 *
 */
int main(void)
{
    uint32_t baud = 115200;
    UDPSOCKET *socket;

    uint32_t ip_addr;
    uint32_t ip_udp_echo;
    int    rc;
    int    packet_nr;
    uint16_t length;

    /*
     * Initialize the uart device.
     */
    NutRegisterDevice(&DEV_CONSOLE, 0, 0);
    freopen(DEV_CONSOLE_NAME, "w", stdout);
    _ioctl(_fileno(stdout), UART_SETSPEED, &baud);
    puts("Demo for ICMP support in UDP sockets...\r\n");

#ifdef DEV_ETHER
#ifndef NUT_UDP_ICMP_SUPPORT
#warning ICMP support for UDP sockets not enabled in the configurator, please enable NUT_UDP_ICMP_SUPPORT
    puts("ICMP support for UDP sockets not enabled in the configurator\r\n");
    puts("Please enable NUT_UDP_ICMP_SUPPORT\r\n");
#endif    
    /*
     * Register the network device.
     */
    puts("Configuring Ethernet interface");
    NutRegisterDevice(&DEV_ETHER, 0, 0);

    ip_addr = inet_addr(MY_IP);
    NutNetIfConfig("eth0", my_mac, ip_addr, inet_addr(MY_MASK));
    NutIpRouteAdd(0, 0, inet_addr(MY_GATE), &DEV_ETHER);

    printf("%s ready\r\n", inet_ntoa(ip_addr));


    socket = NutUdpCreateSocket(UDP_ECHO_PORT);
    if (socket == 0) {
        printf("Could not create UDP socket in port '%d'\r\n", UDP_ECHO_PORT);
        puts("Demo halted...\r\n");
        while (1);
    } else {
        printf("Successfully created UDP socket on port '%d'\r\n", UDP_ECHO_PORT);
        length = UDP_BUFF_SIZE;
        if (NutUdpSetSockOpt(socket, SO_RCVBUF, &length, sizeof(length))) {;
            printf("Could not set UDP receive buffer size (%d)\r\n", length);
            puts("Demo halted...\r\n");
            while (1);
        }
    }
    
    if (NutThreadCreate("RCV", UDPReceiver, (void*)socket, 1024) == 0) {
            puts("Could not start receiver thread\r\n");
            puts("Demo halted...\r\n");
            while (1);
    } else {
        puts("Receiver thread started\r\n");
    }
    
    puts("Starting echo test (1 packet / second)\r\n");
    
    ip_udp_echo = inet_addr(UDP_ECHO_IP);
    packet_nr = 0;
    
    while (1) {
        packet_nr ++;
        sprintf(send_buffer, "Packet: %d", packet_nr);
        rc = NutUdpSendTo(socket, ip_udp_echo, UDP_ECHO_PORT, send_buffer, length);
        printf("--> Sended packet: \"%s\", to %s, rc: %d\r\n", send_buffer, inet_ntoa(ip_udp_echo), rc);
        if (rc < 0) {
#ifdef NUT_UDP_ICMP_SUPPORT
            int      error;
            uint32_t remote_ip;
            uint16_t remote_port;             
            error = NutUdpError(socket, &remote_ip, &remote_port);
            print_udp_icmp_error(remote_ip, remote_port, error);
#endif
        }
        
        NutSleep(1000);
    }
#endif /* DEV_ETHER */
    return 0;
}