source: MondoRescue/branches/2.2.5/mindi-busybox/libbb/create_icmp_socket.c

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * create raw socket for icmp protocol test permission
 * and drop root privileges if running setuid
 *
 */

//#include <sys/types.h>
//#include <netdb.h>
//#include <sys/socket.h>
#include "libbb.h"

int create_icmp_socket(void)
{
    struct protoent *proto;
    int sock;

    proto = getprotobyname("icmp");
    /* if getprotobyname failed, just silently force
     * proto->p_proto to have the correct value for "icmp" */
    sock = socket(AF_INET, SOCK_RAW,
            (proto ? proto->p_proto : 1)); /* 1 == ICMP */
    if (sock < 0) {
        if (errno == EPERM)
            bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
        bb_perror_msg_and_die(bb_msg_can_not_create_raw_socket);
    }

    /* drop root privs if running setuid */
    xsetuid(getuid());

    return sock;
}