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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2018 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <bpf/bpf_helpers.h>
int _version SEC("version") = 1;
SEC("xdp_adjust_tail_shrink")
int _xdp_adjust_tail_shrink(struct xdp_md *xdp)
{
void *data_end = (void *)(long)xdp->data_end;
void *data = (void *)(long)xdp->data;
int offset = 0;
if (data_end - data == 54) /* sizeof(pkt_v4) */
offset = 256; /* shrink too much */
else
offset = 20;
if (bpf_xdp_adjust_tail(xdp, 0 - offset))
return XDP_DROP;
return XDP_TX;
}
char _license[] SEC("license") = "GPL";
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