ebpf_exporter

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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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#include "maps.bpf.h"
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// 17 buckets, max range is 32k..64k
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#define MAX_BUCKET_SLOT 17
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struct key_t {
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    u64 bucket;
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};
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struct {
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    __uint(type, BPF_MAP_TYPE_HASH);
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    __uint(max_entries, MAX_BUCKET_SLOT + 2);
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    __type(key, struct key_t);
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    __type(value, u64);
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} tcp_syn_backlog SEC(".maps");
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static int do_count(u64 backlog)
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{
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    struct key_t key = {};
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    increment_exp2zero_histogram(&tcp_syn_backlog, key, backlog, MAX_BUCKET_SLOT);
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    return 0;
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}
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SEC("kprobe/tcp_v4_syn_recv_sock")
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int BPF_KPROBE(kprobe__tcp_v4_syn_recv_sock, struct sock *sk)
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{
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    return do_count(BPF_CORE_READ(sk, sk_ack_backlog));
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}
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SEC("kprobe/tcp_v6_syn_recv_sock")
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int BPF_KPROBE(kprobe__tcp_v6_syn_recv_sock, struct sock *sk)
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{
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    return do_count(BPF_CORE_READ(sk, sk_ack_backlog));
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}
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char LICENSE[] SEC("license") = "GPL";
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