XS(XS_Net__LibnetRaw_libnet_do_checksum)
[...]
        u_char  buf = (u_char)SvUV(ST(0));
[...]
        RETVAL = libnet_do_checksum(&buf, protocol, len);
        sv_setuv(ST(0), (UV)buf);
        SvSETMAGIC(ST(0));

##</code><code>##

XS(XS_Net__LibnetRaw_libnet_destroy_packet)
[...]
        u_char *        buf = (u_char *)SvPV(ST(0),PL_na);
        RETVAL = libnet_destroy_packet(&buf);

##</code><code>##

    OUTPUT:
        buf    sv_setsv(ST(0),&PL_sv_undef);

##</code><code>##

XS(XS_Net__LibnetRaw_libnet_init_packet)
[...]
        u_char *        buf = (u_char *)SvPV(ST(1),PL_na);
[...]
        RETVAL = libnet_init_packet(p_size, &buf);
        sv_setpv((SV*)ST(1), buf);