source: trunk/minix/commands/simple/ping.c@ 11

/*
ping.c
*/

#define DEBUG   1

#include <sys/types.h>
#include <errno.h>
#include <signal.h>
#include <net/gen/netdb.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <net/gen/oneCsum.h>
#include <fcntl.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#include <net/gen/ip_hdr.h>
#include <net/gen/icmp_hdr.h>
#include <net/gen/ip_io.h>

#define WRITE_SIZE 30
char buffer[16*1024];

int main(int argc, char *argv[]);

#if DEBUG
#define where() fprintf(stderr, "%s %d:", __FILE__, __LINE__);
#endif

#if __STDC__
#define PROTO(x,y) x y
#else
#define PROTO(x,y) X ()
#endif

PROTO (int main, (int argc, char *argv[]) );
static PROTO (void sig_hand, (int signal) );

main(argc, argv)
int argc;
char *argv[];
{
        int fd, i;
        int result, result1;
        nwio_ipopt_t ipopt;
        ip_hdr_t *ip_hdr;
        int ihl;
        icmp_hdr_t *icmp_hdr;
        ipaddr_t dst_addr;
        struct hostent *hostent;
        int length;

        if (argc<2 || argc>3)
        {
                fprintf(stderr, "Usage: %s hostname [-l length] [-t timeout]\n",
                        argv[0]);
                exit(1);
        }
        hostent= gethostbyname(argv[1]);
        if (!hostent)
        {
                dst_addr= inet_addr(argv[1]);
                if (dst_addr == -1)
                {
                        fprintf(stderr, "%s: unknown host (%s)\n",
                                argv[0], argv[1]);
                        exit(1);
                }
        }
        else
                dst_addr= *(ipaddr_t *)(hostent->h_addr);
        if (argc == 3)
        {
                length= strtol (argv[2], (char **)0, 0);
                if (length< sizeof(icmp_hdr_t) + IP_MIN_HDR_SIZE)
                {
                        fprintf(stderr, "%s: length too small (%s)\n",
                                argv[0], argv[2]);
                        exit(1);
                }
        }
        else
                length= WRITE_SIZE;

        fd= open ("/dev/ip", O_RDWR);
        if (fd<0)
                perror("open"), exit(1);

        ipopt.nwio_flags= NWIO_COPY | NWIO_PROTOSPEC;
        ipopt.nwio_proto= 1;

        result= ioctl (fd, NWIOSIPOPT, &ipopt);
        if (result<0)
                perror("ioctl (NWIOSIPOPT)"), exit(1);

        result= ioctl (fd, NWIOGIPOPT, &ipopt);
        if (result<0)
                perror("ioctl (NWIOGIPOPT)"), exit(1);

        for (i= 0; i< 20; i++)
        {
                ip_hdr= (ip_hdr_t *)buffer;
                ip_hdr->ih_dst= dst_addr;

                icmp_hdr= (icmp_hdr_t *)(buffer+20);
                icmp_hdr->ih_type= 8;
                icmp_hdr->ih_code= 0;
                icmp_hdr->ih_chksum= 0;
                icmp_hdr->ih_chksum= ~oneC_sum(0, (u16_t *)icmp_hdr,
                        WRITE_SIZE-20);
                result= write(fd, buffer, length);
                if (result<0)
                {
                        perror("write");
                        exit(1);
                }
                if (result != length)
                {
                        where();
                        fprintf(stderr, "result= %d\n", result);
                        exit(1);
                }

                alarm(0);
                signal (SIGALRM, sig_hand);
                alarm(1);

                result= read(fd, buffer, sizeof(buffer));
                if (result>= 0 || errno != EINTR)
                        break;
        }
        if (i >= 20)
        {
                printf("no answer from %s\n", argv[1]);
                exit(1);
        }
        if (result<0)
        {
                perror ("read");
                exit(1);
        }
        printf("%s is alive\n", argv[1]);
        exit(0);
}

static void sig_hand(signal)
int signal;
{
}