xref: /aosp_15_r20/external/bcc/tools/tcpsynbl.py (revision 387f9dfdfa2baef462e92476d413c7bc2470293e) 
1#!/usr/bin/env python
2# @lint-avoid-python-3-compatibility-imports
3#
4# tcpsynbl      Show TCP SYN backlog.
5#               For Linux, uses BCC, eBPF. Embedded C.
6#
7# USAGE: tcpsynbl [-4 | -6] [-h]
8#
9# Copyright (c) 2019 Brendan Gregg.
10# Licensed under the Apache License, Version 2.0 (the "License").
11# This was originally created for the BPF Performance Tools book
12# published by Addison Wesley. ISBN-13: 9780136554820
13# When copying or porting, include this comment.
14#
15# 03-Jul-2019   Brendan Gregg   Ported from bpftrace to BCC.
16
17from __future__ import print_function
18import argparse
19from bcc import BPF
20from time import sleep
21
22# load BPF program
23bpf_text = """
24#include <net/sock.h>
25
26typedef struct backlog_key {
27    u32 backlog;
28    u64 slot;
29} backlog_key_t;
30
31BPF_HISTOGRAM(dist, backlog_key_t);
32
33int do_entry(struct pt_regs *ctx) {
34    struct sock *sk = (struct sock *)PT_REGS_PARM1(ctx);
35
36    backlog_key_t key = {};
37    key.backlog = sk->sk_max_ack_backlog;
38    key.slot = bpf_log2l(sk->sk_ack_backlog);
39    dist.atomic_increment(key);
40
41    return 0;
42};
43"""
44examples = """examples:
45    ./tcpsynbl          # trace syn backlog
46    ./tcpsynbl -4       # trace IPv4 family only
47    ./tcpsynbl -6       # trace IPv6 family only
48"""
49parser = argparse.ArgumentParser(
50    description="Show TCP SYN backlog.",
51    formatter_class=argparse.RawDescriptionHelpFormatter,
52    epilog=examples)
53group = parser.add_mutually_exclusive_group()
54group.add_argument("-4", "--ipv4", action="store_true",
55    help="trace IPv4 family only")
56group.add_argument("-6", "--ipv6", action="store_true",
57    help="trace IPv6 family only")
58args = parser.parse_args()
59
60b = BPF(text=bpf_text)
61
62if args.ipv4:
63    b.attach_kprobe(event="tcp_v4_syn_recv_sock", fn_name="do_entry")
64elif args.ipv6:
65    b.attach_kprobe(event="tcp_v6_syn_recv_sock", fn_name="do_entry")
66else:
67    b.attach_kprobe(event="tcp_v4_syn_recv_sock", fn_name="do_entry")
68    b.attach_kprobe(event="tcp_v6_syn_recv_sock", fn_name="do_entry")
69
70print("Tracing SYN backlog size. Ctrl-C to end.")
71
72try:
73    sleep(99999999)
74except KeyboardInterrupt:
75    print()
76
77dist = b.get_table("dist")
78dist.print_log2_hist("backlog", "backlog_max")
79