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officeyutong
2023-01-21 20:10:54 +08:00
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4
13-tcpconnlat/README.md
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## eBPF 入门实践教程：
## 备注
对于使用 `libbpf-bootstrap` 的开发，具体见 [tcpconnlat-libbpf-bootstrap.md](tcpconnlat-libbpf-bootstrap.md)
## origin
origin from:

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13-tcpconnlat/libbpf-bootstrap/tcpconnlat.bpf.c Normal file
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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2020 Wenbo Zhang
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_tracing.h>
#include "tcpconnlat.h"
#define AF_INET 2
#define AF_INET6 10
const volatile __u64 targ_min_us = 0;
const volatile pid_t targ_tgid = 0;
struct piddata {
char comm[TASK_COMM_LEN];
u64 ts;
u32 tgid;
};
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 4096);
__type(key, struct sock *);
__type(value, struct piddata);
} start SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
__uint(key_size, sizeof(u32));
__uint(value_size, sizeof(u32));
} events SEC(".maps");
static int trace_connect(struct sock *sk)
{
u32 tgid = bpf_get_current_pid_tgid() >> 32;
struct piddata piddata = {};
if (targ_tgid && targ_tgid != tgid)
return 0;
bpf_get_current_comm(&piddata.comm, sizeof(piddata.comm));
piddata.ts = bpf_ktime_get_ns();
piddata.tgid = tgid;
bpf_map_update_elem(&start, &sk, &piddata, 0);
return 0;
}
static int handle_tcp_rcv_state_process(void *ctx, struct sock *sk)
{
struct piddata *piddatap;
struct event event = {};
s64 delta;
u64 ts;
if (BPF_CORE_READ(sk, __sk_common.skc_state) != TCP_SYN_SENT)
return 0;
piddatap = bpf_map_lookup_elem(&start, &sk);
if (!piddatap)
return 0;
ts = bpf_ktime_get_ns();
delta = (s64)(ts - piddatap->ts);
if (delta < 0)
goto cleanup;
event.delta_us = delta / 1000U;
if (targ_min_us && event.delta_us < targ_min_us)
goto cleanup;
__builtin_memcpy(&event.comm, piddatap->comm,
sizeof(event.comm));
event.ts_us = ts / 1000;
event.tgid = piddatap->tgid;
event.lport = BPF_CORE_READ(sk, __sk_common.skc_num);
event.dport = BPF_CORE_READ(sk, __sk_common.skc_dport);
event.af = BPF_CORE_READ(sk, __sk_common.skc_family);
if (event.af == AF_INET) {
event.saddr_v4 = BPF_CORE_READ(sk, __sk_common.skc_rcv_saddr);
event.daddr_v4 = BPF_CORE_READ(sk, __sk_common.skc_daddr);
} else {
BPF_CORE_READ_INTO(&event.saddr_v6, sk,
__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32);
BPF_CORE_READ_INTO(&event.daddr_v6, sk,
__sk_common.skc_v6_daddr.in6_u.u6_addr32);
}
bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
&event, sizeof(event));
cleanup:
bpf_map_delete_elem(&start, &sk);
return 0;
}
SEC("kprobe/tcp_v4_connect")
int BPF_KPROBE(tcp_v4_connect, struct sock *sk)
{
return trace_connect(sk);
}
SEC("kprobe/tcp_v6_connect")
int BPF_KPROBE(tcp_v6_connect, struct sock *sk)
{
return trace_connect(sk);
}
SEC("kprobe/tcp_rcv_state_process")
int BPF_KPROBE(tcp_rcv_state_process, struct sock *sk)
{
return handle_tcp_rcv_state_process(ctx, sk);
}
SEC("fentry/tcp_v4_connect")
int BPF_PROG(fentry_tcp_v4_connect, struct sock *sk)
{
return trace_connect(sk);
}
SEC("fentry/tcp_v6_connect")
int BPF_PROG(fentry_tcp_v6_connect, struct sock *sk)
{
return trace_connect(sk);
}
SEC("fentry/tcp_rcv_state_process")
int BPF_PROG(fentry_tcp_rcv_state_process, struct sock *sk)
{
return handle_tcp_rcv_state_process(ctx, sk);
}
char LICENSE[] SEC("license") = "GPL";

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13-tcpconnlat/libbpf-bootstrap/tcpconnlat.c Normal file
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// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
// Copyright (c) 2020 Wenbo Zhang
//
// Based on tcpconnlat(8) from BCC by Brendan Gregg.
// 11-Jul-2020 Wenbo Zhang Created this.
#include "tcpconnlat.h"
#include <argp.h>
#include <arpa/inet.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/libbpf.h>
#include <signal.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include "tcpconnlat.skel.h"
// #include "trace_helpers.h"
#define PERF_BUFFER_PAGES 16
#define PERF_POLL_TIMEOUT_MS 100
static volatile sig_atomic_t exiting = 0;
static struct env {
__u64 min_us;
pid_t pid;
bool timestamp;
bool lport;
bool verbose;
} env;
const char* argp_program_version = "tcpconnlat 0.1";
const char* argp_program_bug_address =
"https://github.com/iovisor/bcc/tree/master/libbpf-tools";
const char argp_program_doc[] =
"\nTrace TCP connects and show connection latency.\n"
"\n"
"USAGE: tcpconnlat [--help] [-t] [-p PID] [-L]\n"
"\n"
"EXAMPLES:\n"
" tcpconnlat # summarize on-CPU time as a histogram\n"
" tcpconnlat 1 # trace connection latency slower than 1 ms\n"
" tcpconnlat 0.1 # trace connection latency slower than 100 "
"us\n"
" tcpconnlat -t # 1s summaries, milliseconds, and timestamps\n"
" tcpconnlat -p 185 # trace PID 185 only\n"
" tcpconnlat -L # include LPORT while printing outputs\n";
static const struct argp_option opts[] = {
{"timestamp", 't', NULL, 0, "Include timestamp on output"},
{"pid", 'p', "PID", 0, "Trace this PID only"},
{"lport", 'L', NULL, 0, "Include LPORT on output"},
{"verbose", 'v', NULL, 0, "Verbose debug output"},
{NULL, 'h', NULL, OPTION_HIDDEN, "Show the full help"},
{},
};
static error_t parse_arg(int key, char* arg, struct argp_state* state) {
static int pos_args;
switch (key) {
case 'h':
argp_state_help(state, stderr, ARGP_HELP_STD_HELP);
break;
case 'v':
env.verbose = true;
break;
case 'p':
errno = 0;
env.pid = strtol(arg, NULL, 10);
if (errno) {
fprintf(stderr, "invalid PID: %s\n", arg);
argp_usage(state);
}
break;
case 't':
env.timestamp = true;
break;
case 'L':
env.lport = true;
break;
case ARGP_KEY_ARG:
if (pos_args++) {
fprintf(stderr, "Unrecognized positional argument: %s\n", arg);
argp_usage(state);
}
errno = 0;
env.min_us = strtod(arg, NULL) * 1000;
if (errno || env.min_us <= 0) {
fprintf(stderr, "Invalid delay (in us): %s\n", arg);
argp_usage(state);
}
break;
default:
return ARGP_ERR_UNKNOWN;
}
return 0;
}
static int libbpf_print_fn(enum libbpf_print_level level,
const char* format,
va_list args) {
if (level == LIBBPF_DEBUG && !env.verbose)
return 0;
return vfprintf(stderr, format, args);
}
static void sig_int(int signo) {
exiting = 1;
}
void handle_event(void* ctx, int cpu, void* data, __u32 data_sz) {
const struct event* e = data;
char src[INET6_ADDRSTRLEN];
char dst[INET6_ADDRSTRLEN];
union {
struct in_addr x4;
struct in6_addr x6;
} s, d;
static __u64 start_ts;
if (env.timestamp) {
if (start_ts == 0)
start_ts = e->ts_us;
printf("%-9.3f ", (e->ts_us - start_ts) / 1000000.0);
}
if (e->af == AF_INET) {
s.x4.s_addr = e->saddr_v4;
d.x4.s_addr = e->daddr_v4;
} else if (e->af == AF_INET6) {
memcpy(&s.x6.s6_addr, e->saddr_v6, sizeof(s.x6.s6_addr));
memcpy(&d.x6.s6_addr, e->daddr_v6, sizeof(d.x6.s6_addr));
} else {
fprintf(stderr, "broken event: event->af=%d", e->af);
return;
}
if (env.lport) {
printf("%-6d %-12.12s %-2d %-16s %-6d %-16s %-5d %.2f\n", e->tgid,
e->comm, e->af == AF_INET ? 4 : 6,
inet_ntop(e->af, &s, src, sizeof(src)), e->lport,
inet_ntop(e->af, &d, dst, sizeof(dst)), ntohs(e->dport),
e->delta_us / 1000.0);
} else {
printf("%-6d %-12.12s %-2d %-16s %-16s %-5d %.2f\n", e->tgid, e->comm,
e->af == AF_INET ? 4 : 6, inet_ntop(e->af, &s, src, sizeof(src)),
inet_ntop(e->af, &d, dst, sizeof(dst)), ntohs(e->dport),
e->delta_us / 1000.0);
}
}
void handle_lost_events(void* ctx, int cpu, __u64 lost_cnt) {
fprintf(stderr, "lost %llu events on CPU #%d\n", lost_cnt, cpu);
}
static bool fentry_try_attach(int id) {
int prog_fd, attach_fd;
char error[4096];
struct bpf_insn insns[] = {
{.code = BPF_ALU64 | BPF_MOV | BPF_K, .dst_reg = BPF_REG_0, .imm = 0},
{.code = BPF_JMP | BPF_EXIT},
};
LIBBPF_OPTS(bpf_prog_load_opts, opts,
.expected_attach_type = BPF_TRACE_FENTRY, .attach_btf_id = id,
.log_buf = error, .log_size = sizeof(error), );
prog_fd = bpf_prog_load(BPF_PROG_TYPE_TRACING, "test", "GPL", insns,
sizeof(insns) / sizeof(struct bpf_insn), &opts);
if (prog_fd < 0)
return false;
attach_fd = bpf_raw_tracepoint_open(NULL, prog_fd);
if (attach_fd >= 0)
close(attach_fd);
close(prog_fd);
return attach_fd >= 0;
}
static bool fentry_can_attach(const char* name, const char* mod) {
struct btf *btf, *vmlinux_btf, *module_btf = NULL;
int err, id;
vmlinux_btf = btf__load_vmlinux_btf();
err = libbpf_get_error(vmlinux_btf);
if (err)
return false;
btf = vmlinux_btf;
if (mod) {
module_btf = btf__load_module_btf(mod, vmlinux_btf);
err = libbpf_get_error(module_btf);
if (!err)
btf = module_btf;
}
id = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
btf__free(module_btf);
btf__free(vmlinux_btf);
return id > 0 && fentry_try_attach(id);
}
int main(int argc, char** argv) {
static const struct argp argp = {
.options = opts,
.parser = parse_arg,
.doc = argp_program_doc,
};
struct perf_buffer* pb = NULL;
struct tcpconnlat_bpf* obj;
int err;
err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
if (err)
return err;
libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
libbpf_set_print(libbpf_print_fn);
obj = tcpconnlat_bpf__open();
if (!obj) {
fprintf(stderr, "failed to open BPF object\n");
return 1;
}
/* initialize global data (filtering options) */
obj->rodata->targ_min_us = env.min_us;
obj->rodata->targ_tgid = env.pid;
if (fentry_can_attach("tcp_v4_connect", NULL)) {
bpf_program__set_attach_target(obj->progs.fentry_tcp_v4_connect, 0,
"tcp_v4_connect");
bpf_program__set_attach_target(obj->progs.fentry_tcp_v6_connect, 0,
"tcp_v6_connect");
bpf_program__set_attach_target(obj->progs.fentry_tcp_rcv_state_process,
0, "tcp_rcv_state_process");
bpf_program__set_autoload(obj->progs.tcp_v4_connect, false);
bpf_program__set_autoload(obj->progs.tcp_v6_connect, false);
bpf_program__set_autoload(obj->progs.tcp_rcv_state_process, false);
} else {
bpf_program__set_autoload(obj->progs.fentry_tcp_v4_connect, false);
bpf_program__set_autoload(obj->progs.fentry_tcp_v6_connect, false);
bpf_program__set_autoload(obj->progs.fentry_tcp_rcv_state_process,
false);
}
err = tcpconnlat_bpf__load(obj);
if (err) {
fprintf(stderr, "failed to load BPF object: %d\n", err);
goto cleanup;
}
err = tcpconnlat_bpf__attach(obj);
if (err) {
goto cleanup;
}
pb = perf_buffer__new(bpf_map__fd(obj->maps.events), PERF_BUFFER_PAGES,
handle_event, handle_lost_events, NULL, NULL);
if (!pb) {
fprintf(stderr, "failed to open perf buffer: %d\n", errno);
goto cleanup;
}
/* print header */
if (env.timestamp)
printf("%-9s ", ("TIME(s)"));
if (env.lport) {
printf("%-6s %-12s %-2s %-16s %-6s %-16s %-5s %s\n", "PID", "COMM",
"IP", "SADDR", "LPORT", "DADDR", "DPORT", "LAT(ms)");
} else {
printf("%-6s %-12s %-2s %-16s %-16s %-5s %s\n", "PID", "COMM", "IP",
"SADDR", "DADDR", "DPORT", "LAT(ms)");
}
if (signal(SIGINT, sig_int) == SIG_ERR) {
fprintf(stderr, "can't set signal handler: %s\n", strerror(errno));
err = 1;
goto cleanup;
}
/* main: poll */
while (!exiting) {
err = perf_buffer__poll(pb, PERF_POLL_TIMEOUT_MS);
if (err < 0 && err != -EINTR) {
fprintf(stderr, "error polling perf buffer: %s\n", strerror(-err));
goto cleanup;
}
/* reset err to return 0 if exiting */
err = 0;
}
cleanup:
perf_buffer__free(pb);
tcpconnlat_bpf__destroy(obj);
return err != 0;
}

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13-tcpconnlat/libbpf-bootstrap/tcpconnlat.h Normal file
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/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
#ifndef __TCPCONNLAT_H
#define __TCPCONNLAT_H
// #include <inttypes.h>
typedef unsigned char __u8;
typedef unsigned short __u16;
typedef unsigned int __u32;
typedef unsigned long long __u64;
#define TASK_COMM_LEN 16
struct event {
union {
__u32 saddr_v4;
__u8 saddr_v6[16];
};
union {
__u32 daddr_v4;
__u8 daddr_v6[16];
};
char comm[TASK_COMM_LEN];
__u64 delta_us;
__u64 ts_us;
__u32 tgid;
int af;
__u16 lport;
__u16 dport;
};
#endif /* __TCPCONNLAT_H_ */

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13-tcpconnlat/tcpconnlat-libbpf-bootstrap.md Normal file
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## eBPF入门实践教程：使用 libbpf-bootstrap 开发程序统计 TCP 连接延时
## 来源
修改自 https://github.com/iovisor/bcc/blob/master/libbpf-tools/tcpconnlat.bpf.c
## 编译运行
- ```git clone https://github.com/libbpf/libbpf-bootstrap libbpf-bootstrap-cloned```
- 将 [libbpf-bootstrap](libbpf-bootstrap)目录下的文件复制到 ```libbpf-bootstrap-cloned/examples/c```下
- 修改 ```libbpf-bootstrap-cloned/examples/c/Makefile``` ，在其 ```APPS``` 项后添加 ```tcpconnlat```
- 在 ```libbpf-bootstrap-cloned/examples/c``` 下运行 ```make tcpconnlat```
- ```sudo ./tcpconnlat```
## 效果
```
root@yutong-VirtualBox:~/libbpf-bootstrap/examples/c# ./tcpconnlat
PID COMM IP SADDR DADDR DPORT LAT(ms)
222564 wget 4 192.168.88.15 110.242.68.3 80 25.29
222684 wget 4 192.168.88.15 167.179.101.42 443 246.76
222726 ssh 4 192.168.88.15 167.179.101.42 22 241.17
222774 ssh 4 192.168.88.15 1.15.149.151 22 25.31
```
对于输出的详细解释，详见 [README.md](README.md)
对于源代码的详解，具体见 [tcpconnlat.md](tcpconnlat.md)