40 lines
962 B
Plaintext
Executable File
40 lines
962 B
Plaintext
Executable File
#!/usr/bin/env bpftrace
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/*
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* tcpsynbl - Show TCP SYN backlog as a histogram.
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*
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* See BPF Performance Tools, Chapter 10, for an explanation of this tool.
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*
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* Copyright (c) 2019 Brendan Gregg.
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* Licensed under the Apache License, Version 2.0 (the "License").
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* This was originally created for the BPF Performance Tools book
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* published by Addison Wesley. ISBN-13: 9780136554820
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* When copying or porting, include this comment.
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*
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* 19-Apr-2019 Brendan Gregg Created this.
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*/
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#ifndef BPFTRACE_HAVE_BTF
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#include <net/sock.h>
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#endif
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BEGIN
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{
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printf("Tracing SYN backlog size. Ctrl-C to end.\n");
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}
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kprobe:tcp_v4_syn_recv_sock,
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kprobe:tcp_v6_syn_recv_sock
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{
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$sock = (struct sock *)arg0;
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@backlog[$sock->sk_max_ack_backlog & 0xffffffff] =
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hist($sock->sk_ack_backlog);
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if ($sock->sk_ack_backlog > $sock->sk_max_ack_backlog) {
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time("%H:%M:%S dropping a SYN.\n");
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}
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}
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END
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{
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printf("\n@backlog[backlog limit]: histogram of backlog size\n");
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}
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