eBPF 源于 BPF，本质上是处于内核中的一个高效与灵活的虚拟机组件，以一种安全的方式在许多内核 hook 点执行字节码，开发者可基于 eBPF 开发性能分析工具、软件定义网络、安全等诸多场景。但是，目前对于开发和使用 eBPF 应用而言还可能存在一些不够方便的地方：
eunomia-bpf 是一个开源的 eBPF 动态加载运行时和开发工具链，是为了简化 eBPF 程序的开发、构建、分发、运行而设计的，基于 libbpf 的 CO-RE 轻量级开发框架。
使用 eunomia-bpf ，可以：
eunomia-bpf 由一个编译工具链和一个运行时库组成, 对比传统的 BCC、原生 libbpf 等框架，大幅简化了 eBPF 程序的开发流程，在大多数时候只需编写内核态代码，即可轻松构建、打包、发布完整的 eBPF 应用，同时内核态 eBPF 代码保证和主流的 libbpf, libbpfgo, libbpf-rs 等开发框架的 100% 兼容性。需要编写用户态代码的时候，也可以借助 Webassembly 实现通过多种语言进行用户态开发。和 bpftrace 等脚本工具相比, eunomia-bpf 保留了类似的便捷性, 同时不仅局限于 trace 方面, 可以用于更多的场景, 如网络、安全等等。
- eunomia-bpf 项目 Github 地址: https://github.com/eunomia-bpf/eunomia-bpf
- gitee 镜像: https://gitee.com/anolis/eunomia
我们发布了最新的 0.3 版本, 对于整体的开发和使用流程进行了优化，同时也支持了更多的 eBPF 程序和 maps 类型。
头文件 opensnoop.h
#ifndef __OPENSNOOP_H
#define __OPENSNOOP_H
#define TASK_COMM_LEN 16
#define NAME_MAX 255
#define INVALID_UID ((uid_t)-1)
// used for export event
struct event {
/* user terminology for pid: */
unsigned long long ts;
int pid;
int uid;
int ret;
int flags;
char comm[TASK_COMM_LEN];
char fname[NAME_MAX];
};
#endif /* __OPENSNOOP_H */内核态代码 opensnoop.bpf.c
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include "opensnoop.h"
struct args_t {
const char *fname;
int flags;
};
/// Process ID to trace
const volatile int pid_target = 0;
/// Thread ID to trace
const volatile int tgid_target = 0;
/// @description User ID to trace
const volatile int uid_target = 0;
/// @cmdarg {"default": false, "short": "f", "long": "failed"}
const volatile bool targ_failed = false;
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 10240);
__type(key, u32);
__type(value, struct args_t);
} 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 __always_inline bool valid_uid(uid_t uid) {
return uid != INVALID_UID;
}
static __always_inline
bool trace_allowed(u32 tgid, u32 pid)
{
u32 uid;
/* filters */
if (tgid_target && tgid_target != tgid)
return false;
if (pid_target && pid_target != pid)
return false;
if (valid_uid(uid_target)) {
uid = (u32)bpf_get_current_uid_gid();
if (uid_target != uid) {
return false;
}
}
return true;
}
SEC("tracepoint/syscalls/sys_enter_open")
int tracepoint__syscalls__sys_enter_open(struct trace_event_raw_sys_enter* ctx)
{
u64 id = bpf_get_current_pid_tgid();
/* use kernel terminology here for tgid/pid: */
u32 tgid = id >> 32;
u32 pid = id;
/* store arg info for later lookup */
if (trace_allowed(tgid, pid)) {
struct args_t args = {};
args.fname = (const char *)ctx->args[0];
args.flags = (int)ctx->args[1];
bpf_map_update_elem(&start, &pid, &args, 0);
}
return 0;
}
SEC("tracepoint/syscalls/sys_enter_openat")
int tracepoint__syscalls__sys_enter_openat(struct trace_event_raw_sys_enter* ctx)
{
u64 id = bpf_get_current_pid_tgid();
/* use kernel terminology here for tgid/pid: */
u32 tgid = id >> 32;
u32 pid = id;
/* store arg info for later lookup */
if (trace_allowed(tgid, pid)) {
struct args_t args = {};
args.fname = (const char *)ctx->args[1];
args.flags = (int)ctx->args[2];
bpf_map_update_elem(&start, &pid, &args, 0);
}
return 0;
}
static __always_inline
int trace_exit(struct trace_event_raw_sys_exit* ctx)
{
struct event event = {};
struct args_t *ap;
int ret;
u32 pid = bpf_get_current_pid_tgid();
ap = bpf_map_lookup_elem(&start, &pid);
if (!ap)
return 0; /* missed entry */
ret = ctx->ret;
if (targ_failed && ret >= 0)
goto cleanup; /* want failed only */
/* event data */
event.pid = bpf_get_current_pid_tgid() >> 32;
event.uid = bpf_get_current_uid_gid();
bpf_get_current_comm(&event.comm, sizeof(event.comm));
bpf_probe_read_user_str(&event.fname, sizeof(event.fname), ap->fname);
event.flags = ap->flags;
event.ret = ret;
/* emit event */
bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
&event, sizeof(event));
cleanup:
bpf_map_delete_elem(&start, &pid);
return 0;
}
SEC("tracepoint/syscalls/sys_exit_open")
int tracepoint__syscalls__sys_exit_open(struct trace_event_raw_sys_exit* ctx)
{
return trace_exit(ctx);
}
SEC("tracepoint/syscalls/sys_exit_openat")
int tracepoint__syscalls__sys_exit_openat(struct trace_event_raw_sys_exit* ctx)
{
return trace_exit(ctx);
}
/// Trace open family syscalls.
char LICENSE[] SEC("license") = "GPL";编译运行:
$ ecc opensnoop.bpf.c opensnoop.h
Compiling bpf object...
Generating export types...
Packing ebpf object and config into package.json...
$ sudo ecli examples/bpftools/opensnoop/package.json
TIME TS PID UID RET FLAGS COMM FNAME
20:31:50 0 1 0 51 524288 systemd /proc/614/cgroup
20:31:50 0 33182 0 25 524288 ecli /etc/localtime
20:31:53 0 754 0 6 0 irqbalance /proc/interrupts
20:31:53 0 754 0 6 0 irqbalance /proc/stat
20:32:03 0 754 0 6 0 irqbalance /proc/interrupts
20:32:03 0 754 0 6 0 irqbalance /proc/stat
20:32:03 0 632 0 7 524288 vmtoolsd /etc/mtab
20:32:03 0 632 0 9 0 vmtoolsd /proc/devices
$ sudo ecli examples/bpftools/opensnoop/package.json --pid_target 754
TIME TS PID UID RET FLAGS COMM FNAME
20:34:13 0 754 0 6 0 irqbalance /proc/interrupts
20:34:13 0 754 0 6 0 irqbalance /proc/stat
20:34:23 0 754 0 6 0 irqbalance /proc/interrupts
20:34:23 0 754 0 6 0 irqbalance /proc/stat或使用 docker 编译:
docker run -it -v `pwd`/:/src/ yunwei37/ebpm:latest
编译发布后, 也可以轻松从云端一行命令启动任意 eBPF 程序, 例如:
wget https://aka.pw/bpf-ecli -O ecli && chmod +x ./ecli # download the release from https://github.com/eunomia-bpf/eunomia-bpf/releases/latest/download/ecli
sudo ./ecli https://eunomia-bpf.github.io/eunomia-bpf/sigsnoop/package.json # simply run a pre-compiled ebpf code from a url
sudo ./ecli sigsnoop:latest # run with a name and download the latest version bpf tool from our repo完整代码在这里:https://github.com/eunomia-bpf/eunomia-bpf/tree/master/examples/bpftools/opensnoop
2. 支持根据代码中的注释信息自动生成用户态命令行参数。
比如需要实现一个 ebpf 程序里面的 pid 过滤器，只需要编写内核态代码，在 eBPF 中声明全变量，即可自动生成命令行参数：
/// Process ID to trace
const volatile pid_t pid_target = 0;
/// Thread ID to trace
const volatile pid_t tgid_target = 0;
/// @description User ID to trace
const volatile uid_t uid_target = 0;
/// @cmdarg {"default": false, "short": "f", "long": "failed"}
/// @description target pid to trace
const volatile bool targ_failed = false;我们会将注释文档的描述信息提取，放在配置文件里面，并且变成 eBPF 应用的命令行参数. 使方式以跟踪所有 open 系统调用的 opensnoop 为例：
$ sudo ecli examples/bpftools/opensnoop/package.json -h
Usage: opensnoop_bpf [--help] [--version] [--verbose] [--pid_target VAR][--tgid_target VAR] [--uid_target VAR] [--failed]
Trace open family syscalls.
Optional arguments:
-h, --help shows help message and exits
-v, --version prints version information and exits
--verbose prints libbpf debug information
--pid_target Process ID to trace
--tgid_target Thread ID to trace
$ sudo ecli examples/bpftools/opensnoop/package.json --pid_target 754
TIME TS PID UID RET FLAGS COMM FNAME
20:34:13 0 754 0 6 0 irqbalance /procinterrupts
20:34:13 0 754 0 6 0 irqbalance /proc/stat
20:34:23 0 754 0 6 0 irqbalance /procinterrupts
20:34:23 0 754 0 6 0 irqbalance /proc/stat3 . 支持自动采集和综合非 ring buffer 和 perf event 的 map，比如 hash map，打印出信息或生成直方图。
之前使用 ring buffer 和 perf event 的场景会稍微受限，因此需要有一种方法可以自动从maps 里面采集数据，在源代码里面添加注释即可：
/// @sample {"interval": 1000, "type" : "log2_hist"}
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, MAX_ENTRIES);
__type(key, u32);
__type(value, struct hist);
} hists SEC(".maps");就会每隔一秒去采集一次 counters 里面的内容（print_map），以 runqlat 为例：
$ sudo ecli examples/bpftools/runqlat/package.json -h
Usage: runqlat_bpf [--help] [--version] [--verbose] [--filter_cg][--targ_per_process] [--targ_per_thread] [--targ_per_pidns] [--targ_ms][--targ_tgid VAR]
Summarize run queue (scheduler) latency as a histogram.
Optional arguments:
-h, --help shows help message and exits
-v, --version prints version information and exits
--verbose prints libbpf debug information
--filter_cg set value of bool variable filter_cg
--targ_per_process set value of bool variable targ_per_process
--targ_per_thread set value of bool variable targ_per_thread
--targ_per_pidns set value of bool variable targ_per_pidns
--targ_ms set value of bool variable targ_ms
--targ_tgid set value of pid_t variable targ_tgid
Built with eunomia-bpf framework.
See https://github.com/eunomia-bpf/eunomia-bpf for more information.
$ sudo ecli examples/bpftools/runqlat/package.json
key = 4294967295
comm = rcu_preempt
(unit) : count distribution
0 -> 1 : 9 |**** |
2 -> 3 : 6 |** |
4 -> 7 : 12 |***** |
8 -> 15 : 28 |************* |
16 -> 31 : 40 |******************* |
32 -> 63 : 83 |****************************************|
64 -> 127 : 57 |*************************** |
128 -> 255 : 19 |********* |
256 -> 511 : 11 |***** |
512 -> 1023 : 2 | |
1024 -> 2047 : 2 | |
2048 -> 4095 : 0 | |
4096 -> 8191 : 0 | |
8192 -> 16383 : 0 | |
16384 -> 32767 : 1 | |
$ sudo ecli examples/bpftools/runqlat/package.json --targ_per_process
key = 3189
comm = cpptools
(unit) : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 1 |*** |
16 -> 31 : 2 |******* |
32 -> 63 : 11 |****************************************|
64 -> 127 : 8 |***************************** |
128 -> 255 : 3 |********** |完整代码在这里: https://github.com/eunomia-bpf/eunomia-bpf/tree/masterexamples/bpftools/runqlat
4 . 添加对 uprobe, tc 等多种类型 map 的支持, 允许用标记实现添加额外 attach 信息, 例如:
/// @tchook {"ifindex":1, "attach_point":"BPF_TC_INGRESS"}
/// @tcopts {"handle":1, "priority":1}
SEC("tc")
int tc_ingress(struct __sk_buff *ctx)
{
void *data_end = (void *)(__u64)ctx->data_end;
void *data = (void *)(__u64)ctx->data;
struct ethhdr *l2;
struct iphdr *l3;
if (ctx->protocol != bpf_htons(ETH_P_IP))
return TC_ACT_OK;
l2 = data;
if ((void *)(l2 + 1) > data_end)
return TC_ACT_OK;
l3 = (struct iphdr *)(l2 + 1);
if ((void *)(l3 + 1) > data_end)
return TC_ACT_OK;
bpf_printk("Got IP packet: tot_len: %d, ttl: %d", bpf_ntohs(l3->tot_len), l3->ttl);
return TC_ACT_OK;
}在配置文件中, 可以直接修改 progs/attach 控制挂载点，variables/value 控制全局变量，maps/data 控制在加载 ebpf 程序时往 map 里面放什么数据，export_types/members 控制往用户态传输什么数据格式，而不需要重新编译 eBPF 程序。配置文件和 bpf.o 二进制是配套的，应该搭配使用，或者打包成一个 package.json/yaml 分发。打包的时候会进行压缩，一般来说压缩后的配置文件和二进制合起来的大小在数十 kb 。
配置文件举例:
bpf_skel:
data_sections:
- name: .rodata
variables:
- name: min_duration_ns
type: unsigned long long
value: 100
maps:
- ident: exec_start
name: exec_start
data:
- key: 123
value: 456
- ident: rb
name: rb
- ident: rodata
mmaped: true
name: client_b.rodata
obj_name: client_bpf
progs:
- attach: tp/sched/sched_process_exec
link: true
name: handle_exec
export_types:
- members:
- name: pid
type: int
- name: ppid
type: int
- name: comm
type: char[16]
- name: filename
type: char[127]
- name: exit_event
type: bool
name: event
type_id: 613Install the ecli tool for running eBPF program from the cloud:
$ wget https://aka.pw/bpf-ecli -O ecli && chmod +x ./ecli
$ ./ecli -h
Usage: ecli [--help] [--version] [--json] [--no-cache] url-and-args
....Install the compiler-toolchain for compiling eBPF kernel code to a config file or WASM module:
$ wget https://github.com/eunomia-bpf/eunomia-bpf/releases/latest/download/eunomia.tar.gz
$ tar -xvf eunomia.tar.gz -C ~
$ export PATH=$PATH:~/.eunomia/bin
$ ecc -h
eunomia-bpf compiler
Usage: ecc [OPTIONS] <SOURCE_PATH> [EXPORT_EVENT_HEADER]
....or use the docker image for compile:
docker run -it -v `pwd`/:/src/ yunwei37/ebpm:latest # compile with docker. `pwd` should contains *.bpf.c files and *.h files.
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