BPF_RINGBUF_DISCARD_BIT
hdr_len &= ~BPF_RINGBUF_DISCARD_BIT;
new_len |= BPF_RINGBUF_DISCARD_BIT;
flags = hdr_len & (BPF_RINGBUF_BUSY_BIT | BPF_RINGBUF_DISCARD_BIT);
if (flags & BPF_RINGBUF_DISCARD_BIT) {
if ((len & BPF_RINGBUF_DISCARD_BIT) == 0) {
new_len |= BPF_RINGBUF_DISCARD_BIT;
if (size & (BPF_RINGBUF_BUSY_BIT | BPF_RINGBUF_DISCARD_BIT))