73 lines
1.5 KiB
C
73 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Facebook */
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#include "bpf_iter.h"
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#include "bpf_tracing_net.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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#define bpf_tcp_sk(skc) ({ \
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struct sock_common *_skc = skc; \
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sk = NULL; \
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tp = NULL; \
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if (_skc) { \
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tp = bpf_skc_to_tcp_sock(_skc); \
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sk = (struct sock *)tp; \
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} \
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tp; \
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})
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unsigned short reuse_listen_hport = 0;
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unsigned short listen_hport = 0;
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char cubic_cc[TCP_CA_NAME_MAX] = "bpf_cubic";
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char dctcp_cc[TCP_CA_NAME_MAX] = "bpf_dctcp";
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bool random_retry = false;
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static bool tcp_cc_eq(const char *a, const char *b)
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{
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int i;
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for (i = 0; i < TCP_CA_NAME_MAX; i++) {
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if (a[i] != b[i])
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return false;
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if (!a[i])
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break;
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}
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return true;
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}
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SEC("iter/tcp")
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int change_tcp_cc(struct bpf_iter__tcp *ctx)
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{
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char cur_cc[TCP_CA_NAME_MAX];
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struct tcp_sock *tp;
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struct sock *sk;
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int ret;
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if (!bpf_tcp_sk(ctx->sk_common))
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return 0;
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if (sk->sk_family != AF_INET6 ||
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(sk->sk_state != TCP_LISTEN &&
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sk->sk_state != TCP_ESTABLISHED) ||
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(sk->sk_num != reuse_listen_hport &&
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sk->sk_num != listen_hport &&
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bpf_ntohs(sk->sk_dport) != listen_hport))
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return 0;
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if (bpf_getsockopt(tp, SOL_TCP, TCP_CONGESTION,
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cur_cc, sizeof(cur_cc)))
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return 0;
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if (!tcp_cc_eq(cur_cc, cubic_cc))
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return 0;
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if (random_retry && bpf_get_prandom_u32() % 4 == 1)
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return 1;
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bpf_setsockopt(tp, SOL_TCP, TCP_CONGESTION, dctcp_cc, sizeof(dctcp_cc));
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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