e01b4a72f1
Even though it's not relevant in selftests, the people might still copy-paste from them. So let's take care of optlen > 4096 cases explicitly. Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20230511170456.1759459-4-sdf@google.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
48 lines
1.0 KiB
C
48 lines
1.0 KiB
C
// 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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__u32 page_size = 0;
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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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goto out;
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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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out:
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/* optval larger than PAGE_SIZE use kernel's buffer. */
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if (ctx->optlen > page_size)
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ctx->optlen = 0;
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return 1;
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}
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