40 lines
926 B
C
40 lines
926 B
C
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Facebook */
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#include <string.h>
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#include <linux/tcp.h>
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#include <netinet/in.h>
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_tcp_helpers.h"
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char _license[] SEC("license") = "GPL";
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SEC("cgroup/setsockopt")
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int sockopt_qos_to_cc(struct bpf_sockopt *ctx)
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{
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void *optval_end = ctx->optval_end;
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int *optval = ctx->optval;
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char buf[TCP_CA_NAME_MAX];
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char cc_reno[TCP_CA_NAME_MAX] = "reno";
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char cc_cubic[TCP_CA_NAME_MAX] = "cubic";
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if (ctx->level != SOL_IPV6 || ctx->optname != IPV6_TCLASS)
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return 1;
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if (optval + 1 > optval_end)
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return 0; /* EPERM, bounds check */
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if (bpf_getsockopt(ctx->sk, SOL_TCP, TCP_CONGESTION, &buf, sizeof(buf)))
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return 0;
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if (!tcp_cc_eq(buf, cc_cubic))
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return 0;
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if (*optval == 0x2d) {
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if (bpf_setsockopt(ctx->sk, SOL_TCP, TCP_CONGESTION, &cc_reno,
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sizeof(cc_reno)))
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return 0;
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}
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return 1;
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}
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