Re: [RTnet-users] [ask] how to send and receive packet with real time network in rtnet

[Andreas K. <a.k...@ka...>]

Hello, 

I think you are looking for the following code: 

#include <stdio.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>

#include <rtai_lxrt.h>
#include <rtnet.h>

#define LXRTTASKID 4444

static struct sockaddr_in net_client;
static struct sockaddr_in net_canrouter;

int main( int argc, char **argv )
{
    RT_TASK *lxrttask;
    int sock;

    RTIME start;
    RTIME end;

    char welcomemessage[] = "Welcome";

    /* init network strutures */
    memset( &net_client, 0, sizeof( struct sockaddr_in ) );
    memset( &net_canrouter, 0, sizeof( struct sockaddr_in ) );

    /* disable paging for the current process */
    if ( -1 == mlockall( MCL_CURRENT | MCL_FUTURE ) )
    {
        printf("Error: mlockall failedn");

        exit( EXIT_FAILURE );
    }

    /* local network interface configuration */
    net_client.sin_family = AF_INET;
    net_client.sin_addr.s_addr = INADDR_ANY;
    net_client.sin_port = htons( 333 ); /* local udp port */

    /* udp destinaton configuration */
    net_canrouter.sin_family = AF_INET;
    net_canrouter.sin_addr.s_addr = inet_addr( "192.168.22.1" );
    //printf("INET_ATON: %dn", inet_aton( "192.168.22.1", &net_canrouter.sin_addr) );
    net_canrouter.sin_port= htons( 333 ); /* remode udp port */

    /* create udp socket */
    if ( ( sock = rt_dev_socket( AF_INET, SOCK_DGRAM, 0 ) ) < 0 )
    {
        printf("Error: rt_dev_socketn");

        exit( EXIT_FAILURE );
    }

    /* init realtime task */
    if ( ( lxrttask = rt_task_init( LXRTTASKID, 1, 0, 0 ) ) == NULL )
    {
        rt_dev_close( sock );

        printf("Error: rt_task_initn");

        exit( EXIT_FAILURE );
    }

    printf("switching to hard real time moden");

    /* switch to hard real time mode */
    rt_make_hard_real_time( );

    /* bind local rt socket */
    if ( 0 != rt_dev_bind( sock, (struct sockaddr *) &net_client, sizeof( struct sockaddr_in ) ) )
    {
        rt_make_soft_real_time( );

        rt_dev_close( sock );

        rt_task_delete( lxrttask );

        printf("Error: rt_dev_bindn");

        exit( EXIT_FAILURE );
    }

    /* connect can router */
    if ( 0 != rt_dev_connect( sock, (struct sockaddr *) &net_canrouter, sizeof( struct sockaddr_in ) ) )
    {
        rt_make_soft_real_time( );

        rt_dev_close( sock );

        rt_task_delete( lxrttask );

        printf("Error: rt_dev_connectn");

        exit( EXIT_FAILURE );
    }

    /* rt & network initialization completed */

    printf("sendn");

    /* send welcome message to the can router */
    rt_dev_send( sock, welcomemessage, sizeof( welcomemessage ), 0 );

    printf("=> soft realtimen");

    rt_make_soft_real_time( );

    printf("=> closen");

    rt_dev_close( sock );

    printf("=> task_deleten");

    rt_task_delete( lxrttask );

    printf("=> exitn");

    printf("start: %gnende: %gn", start, end );

    exit( EXIT_SUCCESS );
}

You have to use the following libraries: 

-llxrt -lpthread 

and the following include pathes: 

-I/usr/realtime/include -I/usr/local/rtnet/include 

Andreas Kasper

Zitat Ramon Rusli <mo...@ya...>: 

> Dear,
>
> How can I use rtnet to send or receive packet in c? i am a bit confused because no examples or tutorial to build the program using rtnet while I search it in internet. i want to make a real time packet sending program and a real time packet receiver program using rtnet 0.9.12 and xenomai 2.5.4. the operating system that I use is linux fedora 13 kernel 2.6.32.11. 
>
> Is it just add some include and some lines from standard udp packet server and client program? 
>
> thanks a lot
> ==========================
> //the standard udp packet server that I build (server.c)
> #include <stdio.h>
> #include <stdlib.h>
> #include <unistd.h>
> #include <string.h>
> #include <netinet/in.h>
> #include <arpa/inet.h>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include<mqueue.h>
> #include <fcntl.h>
> #include <sys/stat.h>
> #include <pthread.h>
> #include <sys/mman.h>
> #include <signal.h>
> #include <limits.h>
> #define PORT 7788
> #define BUFLEN 65000
> #define NPACK 10000000
>
> void diep (char *s)
> {
>     perror (s);
>     exit (1);
> }
>
> int main (void)
> {
>     struct sockaddr_in si_me, si_other;
>     int s, i, slen=sizeof(si_other);
>     char buf[BUFLEN];
>
>     if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP))== -1)
>     {
>         diep("socket");    
>     }
>
>     memset ((char *) &si_me, 0, sizeof(si_me));
>     si_me.sin_family = AF_INET;
>     si_me.sin_port = htons(PORT);
>    si_me.sin_addr.s_addr = htonl(INADDR_ANY);
>     if (bind(s, &si_me, sizeof(si_me)) == -1)
>     {
>         diep("bind");
>     }
>
>     for(i = 0; i < NPACK; i++)
>     {
>         if(recvfrom(s, buf, BUFLEN, 0, &si_other, &slen) == -1)
>         {
>             diep("recvfrom()");
>         }
>         printf("received packet from %s:%dn Data: %snn", inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port), buf);
>     }
>     close(s);
>     return 0;
> }
>
>
> =============================
> //the standard udp packet client (client.c)
> #include <stdlib.h>
> #include<unistd.h>
> #include <string.h>
> #include <netinet/in.h>
> #include <arpa/inet.h>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <mqueue.h>
> #include <fcntl.h>
> #include <sys/stat.h>
> #include <pthread.h>
> #include <sys/mman.h>
> #include <signal.h>
> #include <limits.h>
>
> #define PORT 7788
> #define BUFLEN 65000
> #define NPACK 10000000
> #define SRV_IP "167.205.34.150"
>
> void diep (char *s)
> {
>     perror (s);
>     exit (1);
> }
>
> int main ()
> {
>     struct sockaddr_in si_other;
>     int s, i, slen=sizeof(si_other);
>     char buf[BUFLEN];
>
>     if((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
>     {
>         diep("socket");
>    }
>
>     memset((char *) &si_other, 0, sizeof(si_other));
>     si_other.sin_family=AF_INET;
>     si_other.sin_port = htons(PORT);
>     if(inet_aton(SRV_IP, &si_other.sin_addr)==0)
>     {
>         fprintf(stderr, "inet_aton () failedn");
>         exit (1);
>     }    
>
>     for(i=0; i< NPACK; i++)
>     {
>         printf("sending packet %dn", i);
>         sprintf(buf, "This is packet %dn",i);
>         if (sendto(s, buf, BUFLEN, 0, &si_other, slen) == -1)
>         {
>             diep("sendto()");
>        }
>     }
>     close(s);
> return 0;
> }
> ============================