static int parse_iprange(char *p)
{
    char *e;
    u32 ip=0;
    int sh;

    for(sh = 24;; sh -= 8) {
        unsigned long v;

        v = strtoul(p, &e, 10);
        if(p == e || v > 255)
            return 0;

        ip |= v << sh;

        p = e + 1;
        if(*e == '/') {
            v = strtoul(p, &e, 10);
            if(p == e || *e || v > 32)
                return 0;
            if(v) {
                v = 32 - v;
                if(sh > v)
                    return 0;
mask:
                v = ~0 << v;
            }
            scan.start = ip & v;
            scan.end = scan.start - v;
            return 1;
        }

        if(!sh) break;

        v = sh;
        if(!*e)
            goto mask;

        if(*e != '.')
            return 0;

        if(!*p || *p == '*' && !p[1])
            goto mask;
    }

    scan.start = ip;
    scan.end = ip + 1;

    if(*e == '-') {
        u32 end = 0, m = ~0;

        do {
            unsigned long v = strtoul(p, &e, 10);
            if(p == e || v > 255)
                return 0;
            p = e + 1;
            end = end<<8 | v;
            m <<= 8;
        } while(m && *e);

        if(*e)
            return 0;

        end |= ip & m;
        if(end < ip)
            return 0;

        scan.end = end + 1;
        return 1;
    }
    return *e == 0;
}