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