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This commit is contained in:
officeyutong
@@ -1,4 +1,4 @@
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## eBPF 入门实践教程：
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# eBPF 入门实践教程
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## 备注
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@@ -8,7 +8,7 @@
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origin from:
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https://github.com/iovisor/bcc/blob/master/libbpf-tools/tcpconnlat.bpf.c
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<https://github.com/iovisor/bcc/blob/master/libbpf-tools/tcpconnlat.bpf.c>
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## Compile and Run
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@@ -30,10 +30,10 @@ TODO: support union in C
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Demonstrations of tcpconnect, the Linux eBPF/bcc version.
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This tool traces the kernel function performing active TCP connections
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(eg, via a connect() syscall; accept() are passive connections). Some example
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output (IP addresses changed to protect the innocent):
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```console
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# ./tcpconnect
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PID COMM IP SADDR DADDR DPORT
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@@ -43,6 +43,7 @@ PID COMM IP SADDR DADDR DPORT
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1991 telnet 6 ::1 ::1 23
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2015 ssh 6 fe80::2000:bff:fe82:3ac fe80::2000:bff:fe82:3ac 22
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```
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This output shows four connections, one from a "telnet" process, two from
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"curl", and one from "ssh". The output details shows the IP version, source
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address, destination address, and destination port. This traces attempted
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@@ -52,8 +53,8 @@ The overhead of this tool should be negligible, since it is only tracing the
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kernel functions performing connect. It is not tracing every packet and then
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filtering.
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The -t option prints a timestamp column:
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```console
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# ./tcpconnect -t
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TIME(s) PID COMM IP SADDR DADDR DPORT
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@@ -64,6 +65,7 @@ TIME(s) PID COMM IP SADDR DADDR DPORT
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90.928 2482 local_agent 4 10.103.219.236 10.102.64.230 7001
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90.938 2482 local_agent 4 10.103.219.236 10.115.167.169 7101
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```
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The output shows some periodic connections (or attempts) from a "local_agent"
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process to various other addresses. A few connections occur every minute.
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@@ -74,6 +76,7 @@ in this column. Queries for 127.0.0.1 and ::1 are automatically associated with
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"localhost". If the time between when the DNS response was received and a
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connect call was traced exceeds 100ms, the tool will print the time delta
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after the query name. See below for www.domain.com for an example.
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```console
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# ./tcpconnect -d
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PID COMM IP SADDR DADDR DPORT QUERY
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@@ -86,6 +89,7 @@ PID COMM IP SADDR DADDR DPORT QUERY
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```
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The -L option prints a LPORT column:
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```console
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# ./tcpconnect -L
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PID COMM IP SADDR LPORT DADDR DPORT
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@@ -95,6 +99,7 @@ PID COMM IP SADDR LPORT DADDR DPORT
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```
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The -U option prints a UID column:
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```console
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# ./tcpconnect -U
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UID PID COMM IP SADDR DADDR DPORT
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@@ -105,14 +110,17 @@ UID PID COMM IP SADDR DADDR DPORT
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```
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The -u option filtering UID:
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```console
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# ./tcpconnect -Uu 1000
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UID PID COMM IP SADDR DADDR DPORT
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1000 31338 telnet 6 ::1 ::1 23
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1000 31338 telnet 4 127.0.0.1 127.0.0.1 23
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```
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To spot heavy outbound connections quickly one can use the -c flag. It will
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count all active connections per source ip and destination ip/port.
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```console
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# ./tcpconnect.py -c
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Tracing connect ... Hit Ctrl-C to end
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@@ -126,17 +134,18 @@ LADDR RADDR RPORT CONNECTS
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The --cgroupmap option filters based on a cgroup set. It is meant to be used
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with an externally created map.
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```console
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# ./tcpconnect --cgroupmap /sys/fs/bpf/test01
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```
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For more details, see docs/special_filtering.md
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For more details, see docs/special_filtering.md
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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
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## 来源
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修改自 https://github.com/iovisor/bcc/blob/master/libbpf-tools/tcpconnlat.bpf.c
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修改自 <https://github.com/iovisor/bcc/blob/master/libbpf-tools/tcpconnlat.bpf.c>
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## 编译运行
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@@ -147,7 +156,8 @@ For more details, see docs/special_filtering.md
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- ```sudo ./tcpconnlat```
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## 效果
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```
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```plain
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root@yutong-VirtualBox:~/libbpf-bootstrap/examples/c# ./tcpconnlat
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PID COMM IP SADDR DADDR DPORT LAT(ms)
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222564 wget 4 192.168.88.15 110.242.68.3 80 25.29
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@@ -1,4 +1,6 @@
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## eBPF 入门实践教程：编写 eBPF 程序 tcpconnlat 测量 tcp 连接延时
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# eBPF 入门实践教程：编写 eBPF 程序 tcpconnlat 测量 tcp 连接延时
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## 代码解释
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### 背景
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@@ -36,10 +38,9 @@ tcp 连接的整个过程如图所示：
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- 半连接队列，也称 SYN 队列；
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- 全连接队列，也称 accepet 队列；
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服务端收到客户端发起的 SYN 请求后，内核会把该连接存储到半连接队列，并向客户端响应 SYN+ACK，接着客户端会返回 ACK，服务端收到第三次握手的 ACK 后，内核会把连接从半连接队列移除，然后创建新的完全的连接，并将其添加到 accept 队列，等待进程调用 accept 函数时把连接取出来。
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我们的 ebpf 代码实现在 https://github.com/yunwei37/Eunomia/blob/master/bpftools/tcpconnlat/tcpconnlat.bpf.c 中：
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我们的 ebpf 代码实现在 <https://github.com/yunwei37/Eunomia/blob/master/bpftools/tcpconnlat/tcpconnlat.bpf.c> 中：
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它主要使用了 trace_tcp_rcv_state_process 和 kprobe/tcp_v4_connect 这样的跟踪点：
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@@ -48,19 +49,19 @@ tcp 连接的整个过程如图所示：
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SEC("kprobe/tcp_v4_connect")
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int BPF_KPROBE(tcp_v4_connect, struct sock *sk)
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{
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return trace_connect(sk);
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return trace_connect(sk);
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}
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SEC("kprobe/tcp_v6_connect")
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int BPF_KPROBE(tcp_v6_connect, struct sock *sk)
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{
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return trace_connect(sk);
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return trace_connect(sk);
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}
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SEC("kprobe/tcp_rcv_state_process")
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int BPF_KPROBE(tcp_rcv_state_process, struct sock *sk)
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{
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return handle_tcp_rcv_state_process(ctx, sk);
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return handle_tcp_rcv_state_process(ctx, sk);
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}
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```
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@@ -68,25 +69,25 @@ int BPF_KPROBE(tcp_rcv_state_process, struct sock *sk)
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```c
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 4096);
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__type(key, struct sock *);
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__type(value, struct piddata);
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 4096);
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__type(key, struct sock *);
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__type(value, struct piddata);
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} start SEC(".maps");
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static int trace_connect(struct sock *sk)
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{
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u32 tgid = bpf_get_current_pid_tgid() >> 32;
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struct piddata piddata = {};
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u32 tgid = bpf_get_current_pid_tgid() >> 32;
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struct piddata piddata = {};
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if (targ_tgid && targ_tgid != tgid)
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return 0;
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if (targ_tgid && targ_tgid != tgid)
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return 0;
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bpf_get_current_comm(&piddata.comm, sizeof(piddata.comm));
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piddata.ts = bpf_ktime_get_ns();
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piddata.tgid = tgid;
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bpf_map_update_elem(&start, &sk, &piddata, 0);
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return 0;
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bpf_get_current_comm(&piddata.comm, sizeof(piddata.comm));
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piddata.ts = bpf_ktime_get_ns();
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piddata.tgid = tgid;
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bpf_map_update_elem(&start, &sk, &piddata, 0);
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return 0;
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}
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```
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@@ -95,48 +96,48 @@ static int trace_connect(struct sock *sk)
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```c
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static int handle_tcp_rcv_state_process(void *ctx, struct sock *sk)
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{
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struct piddata *piddatap;
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struct event event = {};
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s64 delta;
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u64 ts;
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struct piddata *piddatap;
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struct event event = {};
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s64 delta;
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u64 ts;
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if (BPF_CORE_READ(sk, __sk_common.skc_state) != TCP_SYN_SENT)
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return 0;
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if (BPF_CORE_READ(sk, __sk_common.skc_state) != TCP_SYN_SENT)
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return 0;
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piddatap = bpf_map_lookup_elem(&start, &sk);
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if (!piddatap)
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return 0;
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piddatap = bpf_map_lookup_elem(&start, &sk);
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if (!piddatap)
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return 0;
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ts = bpf_ktime_get_ns();
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delta = (s64)(ts - piddatap->ts);
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if (delta < 0)
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goto cleanup;
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ts = bpf_ktime_get_ns();
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delta = (s64)(ts - piddatap->ts);
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if (delta < 0)
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goto cleanup;
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event.delta_us = delta / 1000U;
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if (targ_min_us && event.delta_us < targ_min_us)
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goto cleanup;
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__builtin_memcpy(&event.comm, piddatap->comm,
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sizeof(event.comm));
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event.ts_us = ts / 1000;
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event.tgid = piddatap->tgid;
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event.lport = BPF_CORE_READ(sk, __sk_common.skc_num);
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event.dport = BPF_CORE_READ(sk, __sk_common.skc_dport);
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event.af = BPF_CORE_READ(sk, __sk_common.skc_family);
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if (event.af == AF_INET) {
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event.saddr_v4 = BPF_CORE_READ(sk, __sk_common.skc_rcv_saddr);
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event.daddr_v4 = BPF_CORE_READ(sk, __sk_common.skc_daddr);
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} else {
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BPF_CORE_READ_INTO(&event.saddr_v6, sk,
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__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32);
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BPF_CORE_READ_INTO(&event.daddr_v6, sk,
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__sk_common.skc_v6_daddr.in6_u.u6_addr32);
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}
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bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
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&event, sizeof(event));
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event.delta_us = delta / 1000U;
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if (targ_min_us && event.delta_us < targ_min_us)
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goto cleanup;
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__builtin_memcpy(&event.comm, piddatap->comm,
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sizeof(event.comm));
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event.ts_us = ts / 1000;
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event.tgid = piddatap->tgid;
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event.lport = BPF_CORE_READ(sk, __sk_common.skc_num);
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event.dport = BPF_CORE_READ(sk, __sk_common.skc_dport);
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event.af = BPF_CORE_READ(sk, __sk_common.skc_family);
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if (event.af == AF_INET) {
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event.saddr_v4 = BPF_CORE_READ(sk, __sk_common.skc_rcv_saddr);
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event.daddr_v4 = BPF_CORE_READ(sk, __sk_common.skc_daddr);
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} else {
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BPF_CORE_READ_INTO(&event.saddr_v6, sk,
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__sk_common.skc_v6_rcv_saddr.in6_u.u6_addr32);
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BPF_CORE_READ_INTO(&event.daddr_v6, sk,
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__sk_common.skc_v6_daddr.in6_u.u6_addr32);
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}
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bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
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&event, sizeof(event));
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cleanup:
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bpf_map_delete_elem(&start, &sk);
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return 0;
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bpf_map_delete_elem(&start, &sk);
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return 0;
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}
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```
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@@ -162,7 +163,7 @@ PID COMM IP SRC DEST PORT LAT(ms) CONATINER
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使用下述查询命令即可看到延时的统计图表：
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```
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```plain
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rate(eunomia_observed_tcpconnlat_v4_histogram_sum[5m])
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/
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rate(eunomia_observed_tcpconnlat_v4_histogram_count[5m])
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@@ -178,9 +179,9 @@ PID COMM IP SRC DEST PORT LAT(ms) CONATINER
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> `Eunomia` 是一个使用 C/C++ 开发的基于 eBPF的轻量级，高性能云原生监控工具，旨在帮助用户了解容器的各项行为、监控可疑的容器安全事件，力求提供覆盖容器全生命周期的轻量级开源监控解决方案。它使用 `Linux` `eBPF` 技术在运行时跟踪您的系统和应用程序，并分析收集的事件以检测可疑的行为模式。目前，它包含性能分析、容器集群网络可视化分析*、容器安全感知告警、一键部署、持久化存储监控等功能，提供了多样化的 ebpf 追踪点。其核心导出器/命令行工具最小仅需要约 4MB 大小的二进制程序，即可在支持的 Linux 内核上启动。
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项目地址：https://github.com/yunwei37/Eunomia
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项目地址：<https://github.com/yunwei37/Eunomia>
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### 参考资料
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1. http://kerneltravel.net/blog/2020/tcpconnlat/
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2. https://network.51cto.com/article/640631.html
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1. <http://kerneltravel.net/blog/2020/tcpconnlat/>
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2. <https://network.51cto.com/article/640631.html>
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