VPP 插件分析与开发

标签：node 插件 VPP plugin 00 next sample 开发 main

Author [email protected]

Date Aug. 07, 2023

Description VPP自定义插件开发demo

在之前的博客：自定义插件中，我们给出了FD.io VPP的sample插件构建方式，但是并没有去真正开发一个插件。

这篇博客给出一个打印数据包IP头部的完整示例。

1. ping插件分析

插件的例子当然可以去看${VPP_HOME}/src/plugins下的所有各个插件代码，但是一般都很麻烦，推荐可以从非常简单的ping的实现开始着手看。

ping一般用于测试网络的连通性。这个插件在VPP中只有三个文件：

$ ls ${VPP_HOME}/src/plugins/ping
CMakeLists.txt  ping.c  ping.h

CMakeLists.txt只包含了添加插件
ping.h：数据结构
ping.c：主体实现，包括ipv4和ipv6的ping实现。

基本的VPP插件开发步骤：

init执行函数定义（VLIB_INIT_FUNCTION(init_func_name)，这是入口）
插件注册：包含版本号以及描述。这里的版本号和描述都用于show plugins命令。
```
VLIB_PLUGIN_REGISTER () = {
    .version = VPP_BUILD_VER,
    .description = "Ping (ping)",
};
```

CLI注册：就看有没有命令行吧，可以是非必须的。

VLIB_CLI_COMMAND (ping_command, static) =
 {
   .path = "ping", // 命令行
   .function = ping_ip_address, // 执行函数，用于解析命令行
   .short_help = "ping {<ip-addr> | ipv4 <ip4-addr> | ipv6 <ip6-addr>}"
   " [ipv4 <ip4-addr> | ipv6 <ip6-addr>] [source <interface>]"
   " [size <pktsize:60>] [interval <sec:1>] [repeat <cnt:5>] [table-id <id:0>]"
   " [burst <count:1>] [verbose]", // 完整配置
   .is_mp_safe = 1, // 多进程安全
 };

节点注册：IPv4和IPv6要分开

VLIB_REGISTER_NODE (ip6_icmp_echo_request_node,static) = {
   .function = ip6_icmp_echo_request, // 执行函数
   .name = "ip6-icmp-echo-request", // 节点名称
   .vector_size = sizeof (u32),
   .format_trace = format_icmp6_input_trace, // format
   .n_next_nodes = ICMP6_ECHO_REQUEST_N_NEXT, // 下一个“可能的节点”的数量
   .next_nodes = {
     [ICMP6_ECHO_REQUEST_NEXT_LOOKUP] = "ip6-lookup", // 下一个节点1
     [ICMP6_ECHO_REQUEST_NEXT_OUTPUT] = "interface-output", // 下一个节点2
   },
 };

node注册位置：可选，ping中没有这个

 VNET_FEATURE_INIT(plugin_sample, static) =
 {
     .arc_name = "ip4-unicast",
     .node_name = "plugin_sample",
     .runs_before = VNET_FEATURES("ip4-lookup"),
 };

配置：在/etc/vpp/startup.conf中的配置。可选，ping中没有这个。

VLIB_CONFIG_FUNCTION (sample_plugin_configure, // 执行函数
 "sample"); // 配置名，例如unix那个，插件名是啥，这里就是啥就行

2. 打印数据包IP头部插件

git clone https://github.com/workerwork/vpp-plugin-sample.git到${VPP_HOME}/src/plugins目录下。这个是我们这个插件参考的。之后就可以直接使用了。不过这个是只支持IPv4的，我们修改一下，让它也支持IPv6。

这个里面只有4个有用的文件CMakeLists.txt plugin_sample.c plugin_sample.h plugin_sample_node.c。其中CMakeLists.txt不需要修改。

2.1. plugin_sample.h

这个里面我们可以修改下版本号，当然实际上改不改也都可以，反正是自定义的。

#ifndef __included_plugin_sample_h__
#define __included_plugin_sample_h__

#include <vnet/vnet.h>
#include <vnet/ip/ip.h>

#include <vppinfra/hash.h>
#include <vppinfra/error.h>
#include <vppinfra/elog.h>

typedef struct {
    /* API message ID base */
    u16 msg_id_base;

    /* convenience */
    vnet_main_t * vnet_main;
} plugin_sample_main_t;

extern plugin_sample_main_t plugin_sample_main;

extern vlib_node_registration_t plugin_sample_node;

#define PLUGIN_SAMPLE_PLUGIN_BUILD_VER "1.1"

#endif /* __included_plugin_sample_h__ */

2.2. plugin_sample.c

在此文件中定义feature和cli。在实现IPv6的打印时，我们把这个功能就实现为默认不开启吧。这样在使用打印数据包IP头部时，就需要自己开启了，在使用中需要注意。

#include <vnet/plugin/plugin.h>
#include <plugin_sample/plugin_sample.h>

plugin_sample_main_t plugin_sample_main;

//开关实现
    static int
plugin_sample_base_enable_disable(u32 sw_if_index, //index
        int enable_disable,
        const char *plug_node_name,
        const char *plugin_name)
{
    vnet_sw_interface_t *sw;
    int ret = 0;

    /* Utterly wrong? */
    //vnet_main结构中的interface_main结构中的sw接口
    if (pool_is_free_index (plugin_sample_main.vnet_main->interface_main.sw_interfaces,
                sw_if_index)) //接口索引
        return VNET_API_ERROR_INVALID_SW_IF_INDEX;

    /* Not a physical port? */
    sw = vnet_get_sw_interface(plugin_sample_main.vnet_main,        //vnet_main结构
            sw_if_index);
    if (sw->type != VNET_SW_INTERFACE_TYPE_HARDWARE)
        return VNET_API_ERROR_INVALID_SW_IF_INDEX;

    vnet_feature_enable_disable(plug_node_name,
            plugin_name,
            sw_if_index,
            enable_disable, 0, 0);

    return ret;
}

    static clib_error_t*
plugin_sample_enable_disable_command_fn(vlib_main_t* vm,        //vlib_main结构
        unformat_input_t *input,
        vlib_cli_command_t *cmd)
{
    u32 sw_if_index = ~0;       //~0 取反全为1
    int enable_disable = 0;

    while(unformat_check_input(input) != UNFORMAT_END_OF_INPUT) //非空则继续输入
    {
        if (unformat(input, "enable"))
            enable_disable = 1;
        if (unformat(input, "disable"))
            enable_disable = 0;
        else if (unformat(input, "%U",
                    unformat_vnet_sw_interface,
                    plugin_sample_main.vnet_main, &sw_if_index));
        else
            break;
    }

    if (sw_if_index == ~0)
        return clib_error_return(0, "Please specify an interface...");

    //调用plugin_sample_base_enable_disable()
    plugin_sample_base_enable_disable(sw_if_index,
            enable_disable,
            "ip4-unicast", //挂载节点
            "plugin_sample");

    return 0;
}
    static clib_error_t*
plugin_sample6_enable_disable_command_fn(vlib_main_t* vm,       //vlib_main结构
        unformat_input_t *input,
        vlib_cli_command_t *cmd)
{
    u32 sw_if_index = ~0;       //~0 取反全为1
    int enable_disable = 0; // 默认为关闭状态

    while(unformat_check_input(input) != UNFORMAT_END_OF_INPUT) //非空则继续输入
    {
        if (unformat(input, "enable"))
            enable_disable = 1;
        else if (unformat(input, "disable"))
            enable_disable = 0;
        else if (unformat(input, "%U",
                    unformat_vnet_sw_interface,
                    plugin_sample_main.vnet_main, &sw_if_index));
        else
            break;
    }

    if (sw_if_index == ~0)
        return clib_error_return(0, "Please specify an interface...");

    //调用plugin_sample_base_enable_disable()
    plugin_sample_base_enable_disable(sw_if_index,
            enable_disable,
            "ip6-unicast", //挂载节点
            "plugin_sample6");

    return 0;
}

//注册开关CLI
//指定interface的开关
VLIB_CLI_COMMAND (plugin_sample_command, static) = {
    .path = "plugin sample",
    .short_help =
        "plugin sample <interface-name> [disable]",
    .function = plugin_sample_enable_disable_command_fn,
};
VLIB_CLI_COMMAND (plugin_sample6_command, static) = {
    .path = "plugin sample6",
    .short_help =
        "plugin sample <interface-name> [enable | disable]",
    .function = plugin_sample6_enable_disable_command_fn,
};

/*注册插件*****start*****/
VLIB_PLUGIN_REGISTER () = {
    .version = PLUGIN_SAMPLE_PLUGIN_BUILD_VER,
    .description = "Print IPv4/IPv6 Header",
};

static clib_error_t *plugin_sample_init(vlib_main_t* vm)
{
    plugin_sample_main.vnet_main = vnet_get_main();
    return 0;
}

VLIB_INIT_FUNCTION(plugin_sample_init);
/*注册插件*****end*****/


//将node注册在ip4-unicast的arc中，指定ip-lookup之前Hook到数据包
VNET_FEATURE_INIT(plugin_sample, static) =
{
    .arc_name = "ip4-unicast",
    .node_name = "plugin_sample",
    .runs_before = VNET_FEATURES("ip4-lookup"),
};
VNET_FEATURE_INIT(plugin_sample6, static) =
{
    .arc_name = "ip6-unicast",
    .node_name = "plugin_sample6",
    .runs_before = VNET_FEATURES("ip6-lookup"),
};

2.3. plugin_sample_node.c

在此文件中定义node和包处理函数。节点注册的时候需要把IPv4和IPv6区分开。

#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vnet/pg/pg.h>
#include <vnet/ethernet/ethernet.h>
#include <vppinfra/error.h>
#include <plugin_sample/plugin_sample.h>

typedef enum
{
    PLUGIN_SAMPLE_NEXT_IP4,
    PLUGIN_SAMPLE_DROP,
    PLUGIN_SAMPLE_NEXT_N,
} plugin_sample_next_t;
typedef enum
{
    PLUGIN_SAMPLE6_NEXT_IP6,
    PLUGIN_SAMPLE6_DROP,
    PLUGIN_SAMPLE6_NEXT_N,
} plugin_sample6_next_t;

typedef struct
{
    u32 next_index;
    u32 sw_if_index;
    u8 new_src_mac[6];
    u8 new_dst_mac[6];
} plugin_sample_trace_t;

#define foreach_plugin_sample_error \
    _(SHOWED, "show packets processed")

typedef enum
{
#define _(sym,str) SAMPLE_ERROR_##sym,
    foreach_plugin_sample_error
#undef _
        SAMPLE_N_ERROR,
} plugin_sample_error_t;


static char *plugin_sample_error_strings[] = {
#define _(sym, str) str,
    foreach_plugin_sample_error
#undef _
};

extern vlib_node_registration_t plugin_sample_node;

    static u8 *
format_plugin_sample_trace (u8 * s, va_list * args)
{
    s = format(s, "To Do!\n");
    return s;
}

//Node处理packet主函数
static uword plugin_sample_node_fn(vlib_main_t *vm, vlib_node_runtime_t *node,
        vlib_frame_t * frame)
{
    u32 n_left_from, *from, *to_next;
    plugin_sample_next_t     next_index;

    from        = vlib_frame_vector_args(frame);
    n_left_from = frame->n_vectors;
    next_index  = node->cached_next_index;

    while(n_left_from > 0){
        u32 n_left_to_next;
        // 从流程中获取包
        vlib_get_next_frame(vm, node, next_index, to_next, n_left_to_next);

        while(n_left_from > 0 && n_left_to_next > 0){
            vlib_buffer_t  *b0;
            u32             bi0, next0 = 0;

            bi0 = to_next[0] = from[0];
            from           += 1;
            to_next        += 1;
            n_left_to_next -= 1;
            n_left_from    -= 1;

            b0 = vlib_get_buffer(vm, bi0);
            //获取到IP header
            void *en0 = vlib_buffer_get_current(b0);
            int i = 0;
            int n = 20;
            //打印前n bytes, 即ip header
            if ((((u8*)en0)[0] & 0xf0) == 0x40)
            {
                n = 20;
            } else if ((((u8*)en0)[0] & 0xf0) == 0x60)
            {
                n = 40;
            }
            for (i = 0; i < n; i++)
            {
                printf("%02x ", *(u8*)(en0+i));
            }
            printf("\n");
            vlib_validate_buffer_enqueue_x1(vm, node, next_index,
                    to_next, n_left_to_next, bi0, next0);
        }
        // 包放回流程中去
        vlib_put_next_frame(vm, node, next_index, n_left_to_next);
    }

    return frame->n_vectors;
}

//注册NODE
//node初始化信息，生成一堆该Node的构造/析构函数
VLIB_REGISTER_NODE (plugin_sample_node) = {
    .name               = "plugin_sample",
    .function       = plugin_sample_node_fn,
    .vector_size    = sizeof(u32),
    .format_trace   = format_plugin_sample_trace,
    .type           = VLIB_NODE_TYPE_INTERNAL,
    .n_errors       = ARRAY_LEN(plugin_sample_error_strings),
    .error_strings  = plugin_sample_error_strings,
    .n_next_nodes   = PLUGIN_SAMPLE_NEXT_N,
    .next_nodes     = {
        [PLUGIN_SAMPLE_NEXT_IP4]    = "ip4-lookup",
        [PLUGIN_SAMPLE_DROP]        = "error-drop",
    },
};
VLIB_REGISTER_NODE (plugin_sample6_node) = {
    .name               = "plugin_sample6",
    .function       = plugin_sample_node_fn,
    .vector_size    = sizeof(u32),
    .format_trace   = format_plugin_sample_trace,
    .type           = VLIB_NODE_TYPE_INTERNAL,
    .n_errors       = ARRAY_LEN(plugin_sample_error_strings),
    .error_strings  = plugin_sample_error_strings,
    .n_next_nodes   = PLUGIN_SAMPLE6_NEXT_N,
    .next_nodes     = {
        [PLUGIN_SAMPLE6_NEXT_IP6]    = "ip6-lookup",
        [PLUGIN_SAMPLE6_DROP]        = "error-drop",
    },
};

3. 使用

在虚拟机中开启了两台Ubuntu20.04的机器，一台安装好了VPP23.06。在/etc/vpp/startup.conf中的配置如下。DPDK插件也需要启用，虽然使用一个接口就可以了，但是懒得修改了。网卡使用桥接方式，这样两台虚拟机就能出于同一个网络中了。

unix {
  nodaemon
  log /var/log/vpp/vpp.log
  full-coredump
  cli-listen /run/vpp/cli.sock
  gid vpp
  interactive
  ## This makes VPP sleep 1ms between each DPDK poll, greatly
  ## reducing CPU usage, at the expense of latency/throughput.
  poll-sleep-usec 1000
  startup-config /etc/vpp/init.dat # this also the CLI cmds.
}

api-trace {
  on
}

api-segment {
  gid vpp
}

socksvr {
  default
}

memory {
  main-heap-size 512M
  main-heap-page-size default-hugepage
}

buffers {
  buffers-per-numa 128000
  default data-size 2048
  page-size default-hugepage
}

statseg {
  size 1G
  page-size default-hugepage
  per-node-counters off
}

cpu {
        main-core 0
}

dpdk {
        dev default {
                num-rx-desc 4096
                num-tx-desc 4096
        }
        dev 0000:00:09.0 {
                name eth1
        }
        dev 0000:00:0a.0 {
                name eth2
        }
}

/etc/vpp/init.dat中的命令配置，其实就是给VPP配接口。当然直接运行起来之后直接敲命令也是可以的。

loopback create-interface
set interface state loop0 up
set interface state eth1 up
set interface state eth2 up
set interface ip address eth1 192.168.12.1/24
set interface ip address eth2 192.168.23.1/24
set ip6 address eth1 2001:db8:1::1/64
set ip6 address eth2 2001:db8:2::1/64

编译插件，并运行。

$ cd ${VPP_HOME}
$ make build
$ make run

# 查看插件
DBGvpp# show plugins

     Plugin                                   Version                          Description
...
 13. plugin_sample_plugin.so                  1.1                              Print IPv4/IPv6 Header
...

# 查看接口地址
DBGvpp# show int addr
eth1 (up):
  L3 192.168.12.1/24
  L3 2001:db8:1::1/64
eth2 (up):
  L3 192.168.23.1/24
  L3 2001:db8:2::1/64
local0 (dn):
loop0 (up):

假设我们是在H1上运行的VPP，那么给H2配置IP地址。请注意，如果使用虚拟机，请保证H1和H2的eth1都在桥接的同一块网卡。

$ sudo ip addr add 192.168.12.2/24 dev eth1
$ sudo ip addr add 2001:db8:1::2/64 dev eth1
$ ping 192.168.12.1 -c 10 &
$ ping 2001:db8:1::1 -c 10 &

然后在VPP中查看：

# 开启IPv4的打印
DBGvpp# plugin sample eth1 enable
DBGvpp# 45 00 00 54 68 ff 40 00 40 01 38 56 c0 a8 0c 02 c0 a8 0c 01
# 开启IPv6的打印
DBGvpp# plugin sample6 eth1 enable
DBGvpp# 60 00 00 00 00 20 3a ff 20 01 0d b8 00 01 00 00 00 00 00 00 00 00 00 02 20 01 0d b8 00 01 00 00 00 00 00 00 00 00 00 01

4. 参考

https://github.com/FDio/hicn/blob/master/hicn-plugin/src/hicn.c
https://workerwork.github.io/posts/vpp-sample-plugin/

标签：node,插件,VPP,plugin,00,next,sample,开发,main
From： https://blog.51cto.com/basilguo/6996318