【SDN】利用Wireshark抓取并分析OpenFlow协议报文

1. 利用Mininet仿真平台构建如下图所示的网络拓扑，配置主机h1和h2的IP地址（h1:10.0.0.1，h2:10.0.0.2），测试两台主机之间的网络连通性。

 

miniedit的设置，使它start CLI，支持OpenFlow 1.0 1.1 1.2 1.3

 

 

 

 2. 利用Wireshark工具，捕获拓扑中交换机与控制器之间的通信数据，对OpenFlow协议类型的各类报文（hello, features_request, features_reply, set_config, packet_in, packet_out等）进行分析，对照wireshark截图写出你的分析内容。（注意应先打开抓包工具Wireshark，选择any进行抓包，再建立拓扑）

  • hello

　　控制器与交换机互相发送Hello消息。Hello消息中只包含有OpenFlow Header，其中的type字段为OFPT_HELLO，version字段为发送方所支持的最高版本OpenFlow。如果双方OpenFlow版本可以兼容，则 OpenFlow 连接建立成功。由于有两个交换机所以有四个hello信息。（这里以端口为60375的交换机为例）

控制器6633端口（最高能支持OpenFlow 1.0） 交换机60375端口

 

 

交换机60375端口（最高能支持OpenFlow 1.3）  控制器6633端口

 

 

 所以双方建立网络连接使用OpenFlow 1.0

 

Features 消息

Features 消息包括 OpenFlow Header 和 Features Reply Message

Features Request

控制器向交换机发送 Features Request 消息查询交换机特性，Features Request 消息只包含 OpenFlow Header，其中 type 字段为 OFPT_FEATURES_REQUEST。

控制器6633端口（我需要你的特征信息） ---> 交换机60375端口

Set Config

 控制器6633端口（请按照我给你的flag和max bytes of packet进行配置） ---> 交换机60375端口

 

 

 Features Reply
交换机60375端口（这是我的特征信息，请查收）--- 控制器6633端口

 

 

 Features 消息包括 OpenFlow Header 和 Features Reply Message
对照Features Reply Message结构

?
1
2
3
4
5
6
7
8
9
10
struct ofp_switch_features{
    struct ofp_header header;
    uint64_t datapath_id; /*唯一标识 id 号*/
    uint32_t n_buffers; /*交缓冲区可以缓存的最大数据包个数*/
    uint8_t n_tables; /*流表数量*/
    uint8_t pad[3]; /*align to 64 bits*/
    uint32_t capabilities; /*支持的特殊功能，具体见 ofp_capabilities*/
    uint32_t actions; /*支持的动作，具体见 ofp_actions_type*/
    struct ofp_phy_port ports[0]; /*物理端口描述列表，具体见 ofp_phy_port*/
};

 对应到抓取到的报文，逐项查看报文内容

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
OpenFlow 1.0
    .000 0001 = Version: 1.0 (0x01)
    Type: OFPT_FEATURES_REPLY (6)
    Length: 176
    Transaction ID: 3238864573
    Datapath unique ID: 0x0000000000000001
        MAC addr: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Implementers part: 0x0001
    n_buffers: 256
    n_tables: 254
    Pad: 000000
    capabilities: 0x000000c7
        .... .... .... .... .... .... .... ...1 = Flow statistics: True
        .... .... .... .... .... .... .... ..1. = Table statistics: True
        .... .... .... .... .... .... .... .1.. = Port statistics: True
        .... .... .... .... .... .... .... 0... = Group statistics: False
        .... .... .... .... .... .... ..0. .... = Can reassemble IP fragments: False
        .... .... .... .... .... .... .1.. .... = Queue statistics: True
        .... .... .... .... .... ...0 .... .... = Switch will block looping ports: False
    actions: 0x00000fff
        .... .... .... .... .... .... .... ...1 = Output to switch port: True
        .... .... .... .... .... .... .... ..1. = Set the 802.1q VLAN id: True
        .... .... .... .... .... .... .... .1.. = Set the 802.1q priority: True
        .... .... .... .... .... .... .... 1... = Strip the 802.1q header: True
        .... .... .... .... .... .... ...1 .... = Ethernet source address: True
        .... .... .... .... .... .... ..1. .... = Ethernet destination address: True
        .... .... .... .... .... .... .1.. .... = IP source address: True
        .... .... .... .... .... .... 1... .... = IP destination address: True
        .... .... .... .... .... ...1 .... .... = IP ToS (DSCP field, 6 bits): True
        .... .... .... .... .... ..1. .... .... = TCP/UDP source port: True
        .... .... .... .... .... .1.. .... .... = TCP/UDP destination port: True
        .... .... .... .... .... 1... .... .... = Output to queue: True
    Port data 1
        Port number: 65534
        HW Address: e6:1d:6e:e8:73:76 (e6:1d:6e:e8:73:76)
        Port Name: s1
        Config flags: 0x00000001
            .... .... .... .... .... .... .... ...1 = Port is administratively down: True
            .... .... .... .... .... .... .... ..0. = Disable 802.1D spanning tree on port: False
            .... .... .... .... .... .... .... .0.. = Drop all packets except 802.1D spanning tree packets: False
            .... .... .... .... .... .... .... 0... = Drop received 802.1D STP packets: False
            .... .... .... .... .... .... ...0 .... = Do not include this port when flooding: False
            .... .... .... .... .... .... ..0. .... = Drop packets forwarded to port: False
            .... .... .... .... .... .... .0.. .... = Do not send packet-in msgs for port: False
        State flags: 0x00000001
            .... .... .... .... .... .... .... ...1 = No physical link present: True
        Current features: 0x00000000
            .... .... .... .... .... .... .... ...0 = 10 Mb half-duplex rate support: False
            .... .... .... .... .... .... .... ..0. = 10 Mb full-duplex rate support: False
            .... .... .... .... .... .... .... .0.. = 100 Mb half-duplex rate support: False
            .... .... .... .... .... .... .... 0... = 100 Mb full-duplex rate support: False
            .... .... .... .... .... .... ...0 .... = 1 Gb half-duplex rate support: False
            .... .... .... .... .... .... ..0. .... = 1 Gb full-duplex rate support: False
            .... .... .... .... .... .... .0.. .... = 10 Gb full-duplex rate support: False
            .... .... .... .... .... .... 0... .... = Copper medium: False
            .... .... .... .... .... ...0 .... .... = Fiber medium: False
            .... .... .... .... .... ..0. .... .... = Auto-negotiation: False
            .... .... .... .... .... .0.. .... .... = Pause: False
            .... .... .... .... .... 0... .... .... = Asymmetric pause: False
        Advertised features: 0x00000000
        Features supported: 0x00000000
        Features advertised by peer: 0x00000000
    Port data 2
        Port number: 1
        HW Address: 3e:ea:d0:35:c4:14 (3e:ea:d0:35:c4:14)
        Port Name: s1-eth1
        Config flags: 0x00000000
            .... .... .... .... .... .... .... ...0 = Port is administratively down: False
            .... .... .... .... .... .... .... ..0. = Disable 802.1D spanning tree on port: False
            .... .... .... .... .... .... .... .0.. = Drop all packets except 802.1D spanning tree packets: False
            .... .... .... .... .... .... .... 0... = Drop received 802.1D STP packets: False
            .... .... .... .... .... .... ...0 .... = Do not include this port when flooding: False
            .... .... .... .... .... .... ..0. .... = Drop packets forwarded to port: False
            .... .... .... .... .... .... .0.. .... = Do not send packet-in msgs for port: False
        State flags: 0x00000000
            .... .... .... .... .... .... .... ...0 = No physical link present: False
        Current features: 0x000000c0
            .... .... .... .... .... .... .... ...0 = 10 Mb half-duplex rate support: False
            .... .... .... .... .... .... .... ..0. = 10 Mb full-duplex rate support: False
            .... .... .... .... .... .... .... .0.. = 100 Mb half-duplex rate support: False
            .... .... .... .... .... .... .... 0... = 100 Mb full-duplex rate support: False
            .... .... .... .... .... .... ...0 .... = 1 Gb half-duplex rate support: False
            .... .... .... .... .... .... ..0. .... = 1 Gb full-duplex rate support: False
            .... .... .... .... .... .... .1.. .... = 10 Gb full-duplex rate support: True
            .... .... .... .... .... .... 1... .... = Copper medium: True
            .... .... .... .... .... ...0 .... .... = Fiber medium: False
            .... .... .... .... .... ..0. .... .... = Auto-negotiation: False
            .... .... .... .... .... .0.. .... .... = Pause: False
            .... .... .... .... .... 0... .... .... = Asymmetric pause: False
        Advertised features: 0x00000000
        Features supported: 0x00000000
        Features advertised by peer: 0x00000000
    Port data 3
        Port number: 2
        HW Address: 82:de:cd:5b:b7:73 (82:de:cd:5b:b7:73)
        Port Name: s1-eth2
        Config flags: 0x00000000
            .... .... .... .... .... .... .... ...0 = Port is administratively down: False
            .... .... .... .... .... .... .... ..0. = Disable 802.1D spanning tree on port: False
            .... .... .... .... .... .... .... .0.. = Drop all packets except 802.1D spanning tree packets: False
            .... .... .... .... .... .... .... 0... = Drop received 802.1D STP packets: False
            .... .... .... .... .... .... ...0 .... = Do not include this port when flooding: False
            .... .... .... .... .... .... ..0. .... = Drop packets forwarded to port: False
            .... .... .... .... .... .... .0.. .... = Do not send packet-in msgs for port: False
        State flags: 0x00000000
            .... .... .... .... .... .... .... ...0 = No physical link present: False
        Current features: 0x000000c0
            .... .... .... .... .... .... .... ...0 = 10 Mb half-duplex rate support: False
            .... .... .... .... .... .... .... ..0. = 10 Mb full-duplex rate support: False
            .... .... .... .... .... .... .... .0.. = 100 Mb half-duplex rate support: False
            .... .... .... .... .... .... .... 0... = 100 Mb full-duplex rate support: False
            .... .... .... .... .... .... ...0 .... = 1 Gb half-duplex rate support: False
            .... .... .... .... .... .... ..0. .... = 1 Gb full-duplex rate support: False
            .... .... .... .... .... .... .1.. .... = 10 Gb full-duplex rate support: True
            .... .... .... .... .... .... 1... .... = Copper medium: True
            .... .... .... .... .... ...0 .... .... = Fiber medium: False
            .... .... .... .... .... ..0. .... .... = Auto-negotiation: False
            .... .... .... .... .... .0.. .... .... = Pause: False
            .... .... .... .... .... 0... .... .... = Asymmetric pause: False
        Advertised features: 0x00000000
        Features supported: 0x00000000
        Features advertised by peer: 0x00000000

 

Packet_in
交换机60375端口（有数据包进来，请指示）--- 控制器6633端口

 

 

 

 结合Packet_in的结构

复制代码
struct ofp_packet_in {
    struct ofp_header header;
    uint32_t buffer_id; /*Packet-in消息所携带的数据包在交换机缓存区中的ID*/
    uint16_t total_len; /*data字段的长度*/
    uint16_t in_port; /*数据包进入交换机时的端口号*/
    uint8_t reason; /*发送Packet-in消息的原因，具体见 ofp_packet_in_reason*/
    uint8_t pad;
    uint8_t data[0]; /*携带的数据包*/
};
复制代码

分析抓取的数据包，可以发现是因为交换机发现此时自己并没有匹配的流表（Reason: No matching flow (table-miss flow entry) (0)），所以要问控制器如何处理

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
OpenFlow 1.0
    .000 0001 = Version: 1.0 (0x01)
    Type: OFPT_PACKET_IN (10)
    Length: 108
    Transaction ID: 0
    Buffer Id: 0x00000100
    Total length: 90
    In port: 2
    Reason: No matching flow (table-miss flow entry) (0)
    Pad: 00
    Ethernet II, Src: 0e:b1:dd:f7:50:53 (0e:b1:dd:f7:50:53), Dst: IPv6mcast_16 (33:33:00:00:00:16)
        Destination: IPv6mcast_16 (33:33:00:00:00:16)
            Address: IPv6mcast_16 (33:33:00:00:00:16)
            .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
            .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
        Source: 0e:b1:dd:f7:50:53 (0e:b1:dd:f7:50:53)
            Address: 0e:b1:dd:f7:50:53 (0e:b1:dd:f7:50:53)
            .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
            .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        Type: IPv6 (0x86dd)
    Internet Protocol Version 6, Src: ::, Dst: ff02::16
        0110 .... = Version: 6
        .... 0000 0000 .... .... .... .... .... = Traffic Class: 0x00 (DSCP: CS0, ECN: Not-ECT)
            .... 0000 00.. .... .... .... .... .... = Differentiated Services Codepoint: Default (0)
            .... .... ..00 .... .... .... .... .... = Explicit Congestion Notification: Not ECN-Capable Transport (0)
        .... .... .... 0000 0000 0000 0000 0000 = Flow Label: 0x00000
        Payload Length: 36
        Next Header: IPv6 Hop-by-Hop Option (0)
        Hop Limit: 1
        Source Address: ::
        Destination Address: ff02::16
        IPv6 Hop-by-Hop Option
            Next Header: ICMPv6 (58)
            Length: 0
            [Length: 8 bytes]
            Router Alert
                Type: Router Alert (0x05)
                    00.. .... = Action: Skip and continue (0)
                    ..0. .... = May Change: No
                    ...0 0101 = Low-Order Bits: 0x05
                Length: 2
                Router Alert: MLD (0)
            PadN
                Type: PadN (0x01)
                    00.. .... = Action: Skip and continue (0)
                    ..0. .... = May Change: No
                    ...0 0001 = Low-Order Bits: 0x01
                Length: 0
                PadN: <none>
    Internet Control Message Protocol v6
        Type: Multicast Listener Report Message v2 (143)
        Code: 0
        Checksum: 0x1e40 [correct]
        [Checksum Status: Good]
        Reserved: 0000
        Number of Multicast Address Records: 1
        Multicast Address Record Changed to exclude: ff02::1:fff7:5053
            Record Type: Changed to exclude (4)
            Aux Data Len: 0
            Number of Sources: 0
            Multicast Address: ff02::1:fff7:5053

 Packet_out

控制器6633端口（请按照我给你的action进行处理） ---> 交换机60375端口

 

 

 结合Packet_out的结构

?
1
2
3
4
5
6
7
8
struct ofp_packet_out {
    struct ofp_header header;
    uint32_t buffer_id; /*交换机缓存区id，如果为-1则指定的为packet-out消息携带的data字段*/
    uint16_t in_port; /*如果buffer_id为‐1，并且action列表中指定了Output=TABLE的动作,in_port将作为data段数据包的额外匹配信息进行流表查询*/
    uint16_t actions_len; /*action列表的长度，可以用来区分actions和data段*/
    struct ofp_action_header actions[0]; /*动作列表*/
    uint8_t data[0]; /*数据缓存区，可以存储一个以太网帧，可选*/
}

 告诉输出到交换机的65531端口

?
1
2
3
4
5
6
7
8
9
10
11
12
OpenFlow 1.0
    .000 0001 = Version: 1.0 (0x01)
    Type: OFPT_PACKET_OUT (13)
    Length: 24
    Transaction ID: 0
    Buffer Id: 0x00000100
    In port: 2
    Actions length: 8
    Actions type: Output to switch port (0)
    Action length: 8
    Output port: 65531
    Max length: 0

 

接下来是另一台交换机（端口60376）与控制器（端口6633）的交互过程

 

 

h1 ping h2

packet_in

 

 flow_mod

flow_mod结构

?
1
2
3
4
5
6
7
8
9
10
11
12
13
struct ofp_flow_mod {
    struct ofp_header header;
    struct ofp_match match; /*流表的匹配域*/
    uint64_t cookie; /*流表项标识符*/
    uint16_t command; /*可以是ADD,DELETE,DELETE-STRICT,MODIFY,MODIFY-STRICT*/
    uint16_t idle_timeout; /*空闲超时时间*/
    uint16_t hard_timeout; /*最大生存时间*/
    uint16_t priority; /*优先级，优先级高的流表项优先匹配*/
    uint32_t buffer_id; /*缓存区ID ,用于指定缓存区中的一个数据包按这个消息的action列表处理*/ 
    uint16_t out_port; /*如果这条消息是用于删除流表则需要提供额外的匹配参数*/
    uint16_t flags; /*标志位，可以用来指示流表删除后是否发送flow‐removed消息，添加流表时是否检查流表重复项，添加的流表项是否为应急流表项。*/
    struct ofp_action_header actions[0]; /*action列表*/
};

 分析抓取的flow_mod数据包，控制器通过6633端口向交换机60375端口、交换机60376端口下发流表项，指导数据的转发处理

 

 

 

 

 

 

 

 

 原文转自：https://www.cnblogs.com/lyhtsl/p/11869668.html

　　　　　 https://www.cnblogs.com/fjlinww/p/11834092.html　

posted @   One7  阅读(2364)  评论(0)  编辑  收藏  举报
编辑推荐：
· .NET Core 中如何实现缓存的预热？
· 从 HTTP 原因短语缺失研究 HTTP/2 和 HTTP/3 的设计差异
· AI与.NET技术实操系列：向量存储与相似性搜索在 .NET 中的实现
· 基于Microsoft.Extensions.AI核心库实现RAG应用
· Linux系列：如何用heaptrack跟踪.NET程序的非托管内存泄露
阅读排行：
· TypeScript + Deepseek 打造卜卦网站：技术与玄学的结合
· Manus的开源复刻OpenManus初探
· .NET Core 中如何实现缓存的预热？
· 三行代码完成国际化适配，妙~啊~
· 阿里巴巴 QwQ-32B真的超越了 DeepSeek R-1吗？
点击右上角即可分享
微信分享提示
SQL AI 助手