ebpf_exporter

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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include "maps.bpf.h"
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#define UPPER_PORT_BOUND 32768
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struct {
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    __uint(type, BPF_MAP_TYPE_HASH);
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    __uint(max_entries, UPPER_PORT_BOUND);
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    __type(key, u16);
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    __type(value, u64);
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} udp_fail_queue_rcv_skbs_total SEC(".maps");
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SEC("tp_btf/udp_fail_queue_rcv_skb")
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int BPF_PROG(udp_fail_queue_rcv_skb, int rc, struct sock *sk)
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{
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    u16 lport = sk->__sk_common.skc_num;
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    // We are not interested in ephemeral ports for outbound connections.
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    // There's a ton of them and they don't easily correlate with services.
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    // To still have some visibility, we put all of the ephemeral ports into
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    // the same local_port="0" label and defer to debugging with tracepoints
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    // to find what port and service are having issues.
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    if (lport >= UPPER_PORT_BOUND) {
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        lport = 0;
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    }
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    increment_map(&udp_fail_queue_rcv_skbs_total, &lport, 1);
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    return 0;
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}
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char LICENSE[] SEC("license") = "GPL";
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