进行网络运维,必须对网络拓扑情况进行详细的掌握,但是网络改动后,更新网络拓扑比较繁琐,维护人员容易懈怠,久而久之,通过人工绘制的网络拓扑很容易与现有网络出现偏差。
现在,可以通过python 丰富的库,结合CDP邻居信息,自动绘制网络拓扑信息,以下是实现思路:
1、登录设备,获取邻居信息;
工具:python(telnetlib、paramiko、netmiko库)
2、筛选需要的信息,设备本地IP,本地名称,本地接口,对端设备名称,对端接口,对端IP
工具:python(textfsm、json库)
3、根据获取进行进行画图
工具:python(N2G库)
文档说明:https://n2g.readthedocs.io/en/latest/diagram_plugins/DrawIo Module.html
4、调整图形。
一、通过python登录交换机设备的案例很多,在此不再赘述,各位可以在网上找到通过telnet、ssh的方式登录交换机,根据实际情况进行调整;这里后续通过telnet方式登录设备,输入show cdp nei detali 获取信息。
二、邻居信息处理
2.1获取邻居信息
输入命令后,获取交换机邻居信息如下:
1 QIA.JSJZX.JKS>show cdp nei
2 -------------------------
3 Device ID: qia.b3.net.test.sw01
4 Entry address(es):
5 IP address: 192.17.190.225
6 Platform: cisco WS-C2960X-24TS-L, Capabilities: Switch IGMP
7 Interface: GigabitEthernet1/0/24, Port ID (outgoing port): GigabitEthernet1/0/23
8 Holdtime : 126 sec
9
10 Version :
11 Cisco IOS Software, C2960X Software (C2960X-UNIVERSALK9-M), Version 15.2(2)E6, RELEASE SOFTWARE (fc1)
12 Technical Support: http://www.cisco.com/techsupport
13 Copyright (c) 1986-2016 by Cisco Systems, Inc.
14 Compiled Fri 16-Dec-16 21:27 by prod_rel_team
15
16 advertisement version: 2
17 Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF000000000000F87B20311580FF0000
18 VTP Management Domain: ''
19 Native VLAN: 1
20 Duplex: full
21 Power Available TLV:
22
23 Power request id: 0, Power management id: 1, Power available: 0, Power management level: -1
24 Management address(es):
25 IP address: 192.17.190.225
26
27 -------------------------
28 Device ID: qia.b3.net.test.sw03
29 Entry address(es):
30 IP address: 192.17.191.132
31 Platform: cisco WS-C2960S-48TD-L, Capabilities: Switch IGMP
32 Interface: GigabitEthernet1/0/23, Port ID (outgoing port): GigabitEthernet1/0/48
33 Holdtime : 134 sec
34
35 Version :
36 Cisco IOS Software, C2960S Software (C2960S-UNIVERSALK9-M), Version 12.2(55)SE7, RELEASE SOFTWARE (fc1)
37 Technical Support: http://www.cisco.com/techsupport
38 Copyright (c) 1986-2013 by Cisco Systems, Inc.
39 Compiled Mon 28-Jan-13 10:28 by prod_rel_team
40
41 advertisement version: 2
42 Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF000000000000B000B4865F80FF0000
43 VTP Management Domain: 'default'
44 Native VLAN: 1
45 Duplex: full
46 Power Available TLV:
47
48 Power request id: 0, Power management id: 1, Power available: 0, Power management level: -1
49 Management address(es):
50 IP address: 192.19.191.132
上述为邻居信息字段,标红部分为需要提取的信息内容,下面通过textfsm工具进行提取,获取到信息内容分别为:本机名称,邻居主机名称、邻居主机IP、本机接口、邻居接口;以下是自定义的textfsm模板,文件保存为cisco_tfm.template。
1 Value Local_hostname (\S+)
2 Value Key Local_port (\S+)
3 Value Device_name (\S+)
4 Value Device_module (\S+)
5 Value Device_IP (\S+)
6 Value Required Device_port (\S+)
7
8
9 Start
10 ^${Local_hostname}>
11 ^Device ID: ${Device_name}
12 ^\s+IP\saddress: ${Device_IP}
13 ^Platform: cisco ${Device_module},
14 ^Interface: ${Local_port},\s+Port\sID\s\(outgoing\sport\):\s${Device_port} -> Record
代码实现:
1 import textfsm
2
3
4 #cisco :show cdp nei detail
5 data = """
6 QIA.JSJZX.JKS>show cdp nei
7 -------------------------
8 Device ID: qia.b3.net.test.sw01
9 Entry address(es):
10 IP address: 192.17.190.225
11 Platform: cisco WS-C2960X-24TS-L, Capabilities: Switch IGMP
12 Interface: GigabitEthernet1/0/24, Port ID (outgoing port): GigabitEthernet1/0/23
13 Holdtime : 126 sec
14
15 Version :
16 Cisco IOS Software, C2960X Software (C2960X-UNIVERSALK9-M), Version 15.2(2)E6, RELEASE SOFTWARE (fc1)
17 Technical Support: http://www.cisco.com/techsupport
18 Copyright (c) 1986-2016 by Cisco Systems, Inc.
19 Compiled Fri 16-Dec-16 21:27 by prod_rel_team
20
21 advertisement version: 2
22 Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF000000000000F87B20311580FF0000
23 VTP Management Domain: ''
24 Native VLAN: 1
25 Duplex: full
26 Power Available TLV:
27
28 Power request id: 0, Power management id: 1, Power available: 0, Power management level: -1
29 Management address(es):
30 IP address: 192.17.190.225
31
32 -------------------------
33 Device ID: qia.b3.net.test.sw03
34 Entry address(es):
35 IP address: 192.17.191.132
36 Platform: cisco WS-C2960S-48TD-L, Capabilities: Switch IGMP
37 Interface: GigabitEthernet1/0/23, Port ID (outgoing port): GigabitEthernet1/0/48
38 Holdtime : 134 sec
39
40 Version :
41 Cisco IOS Software, C2960S Software (C2960S-UNIVERSALK9-M), Version 12.2(55)SE7, RELEASE SOFTWARE (fc1)
42 Technical Support: http://www.cisco.com/techsupport
43 Copyright (c) 1986-2013 by Cisco Systems, Inc.
44 Compiled Mon 28-Jan-13 10:28 by prod_rel_team
45
46 advertisement version: 2
47 Protocol Hello: OUI=0x00000C, Protocol ID=0x0112; payload len=27, value=00000000FFFFFFFF010221FF000000000000B000B4865F80FF0000
48 VTP Management Domain: 'default'
49 Native VLAN: 1
50 Duplex: full
51 Power Available TLV:
52
53 Power request id: 0, Power management id: 1, Power available: 0, Power management level: -1
54 Management address(es):
55 IP address: 192.17.191.132
56 """
57
58 template_file = ".\cisco_tfm.template"
59
60 with open(template_file) as template:
61 fsm = textfsm.TextFSM(template)
62 result = fsm.ParseText(data)
63 # print(fsm.header)
64 print(result)
65 # print(len(result))
输出内容:
['Local_hostname', 'Local_port', 'Device_name', 'Device_module', 'Device_IP', 'Device_port']
[['QIA.JSJZX.JKS', 'GigabitEthernet1/0/24', 'qia.b3.net.test.sw01', 'WS-C2960X-24TS-L', '192.17.190.225', 'GigabitEthernet1/0/23'],
['', 'GigabitEthernet1/0/23', 'qia.b3.net.test.sw03', 'WS-C2960S-48TD-L', '192.17.191.132', 'GigabitEthernet1/0/48']]
注意:以上内容中,本地主机名仅在第一个邻居信息表中显示,所以需要当前设备邻居进行数据进行格式化,因此就需要用到json库。
2.2 邻居信息数据格式化
通过数据格式转换,可以得到当前主机IP、主机名称、主机接口;邻居IP、邻居名称、邻居接口信息;
代码实现:
1 import json
2
3 ip_address = '192.168.1.1'
4 # hostname = 'zh_cisco_2960'
5
6 cdp_data = [
7 ['9QI.JSJZX.JKS', 'GigabitEthernet1/0/24', '9qi.b3.net.test.sw01', 'WS-C2960X-24TS-L', '172.17.190.225', 'GigabitEthernet1/0/23'],
8 ['', 'GigabitEthernet1/0/23', '9qi.b3.net.test.sw03', 'WS-C2960S-48TD-L', '172.17.191.132', 'GigabitEthernet1/0/48']
9 ]
10
11 def data_format(ip_address,cdp_data):
12
13 hostname = cdp_data[0][0]#二层列表格式,获取主机名
14 result_data = {
15 ip_address: {
16 hostname: {item[1]: item[2:] for item in cdp_data}
17 }
18 }
19 json_data = json.dumps(result_data, indent=2)
20
21 return json_data
22 # return the JSON formatted string
23
24 if __name__ == "__main__":
25 json_data1 = data_format(ip_address,cdp_data)
26 print(json_data1)
Json_CDPInfo
输出信息:
1 {
2 "192.168.1.1": {#当前设备IP
3 "QI.JSJZX.JKS": {#当前设备名称
4 "GigabitEthernet1/0/24": [#本地接口,
5 "qia.b3.net.test.sw01",#邻居信息
6 "WS-C2960X-24TS-L",
7 "192.17.190.225",
8 "GigabitEthernet1/0/23"
9 ],
10 "GigabitEthernet1/0/23": [
11 "qia.b3.net.test.sw03",
12 "WS-C2960S-48TD-L",
13 "192.17.191.132",
14 "GigabitEthernet1/0/48"
15 ]
16 }
17 }
18 }
View Code
格式化以上邻居数据后,便于后续对数据进行遍历,在第三步进行读取数据进行增加节点。
遍历数据:
1 import json
2
3 # 读取 JSON 数据
4 json_data = '''
5 {
6 "192.168.1.1": {
7 "QIA.JSJZX.JKS": {
8 "GigabitEthernet1/0/24": [
9 "qia.b3.net.test.sw01",
10 "WS-C2960X-24TS-L",
11 "192.17.190.225",
12 "GigabitEthernet1/0/23"
13 ],
14 "GigabitEthernet1/0/23": [
15 "qia.b3.net.test.sw03",
16 "WS-C2960S-48TD-L",
17 "192.17.191.132",
18 "GigabitEthernet1/0/48"
19 ]
20 }
21 }
22 }
23
24 '''
25
26 # 解析 JSON 数据
27 parsed_data = json.loads(json_data)
28
29 # 遍历数据
30 for ip_address, inner_data in parsed_data.items():
31 print(f"IP Address: {ip_address}")# 获取主机IP地址
32 # print(f"host: {inner_data}")
33
34 for hostname, cdp_data in inner_data.items():
35 print(f"Hostname: {hostname}") #获取主机名称
36 # print(type(cdp_data))
37
38 for key, values in cdp_data.items():
39 print(values)
View Code
这里在每个节点获取到邻居信息,就可以根据信息,在拓扑图中增加节点信息了。
三、进行画图、
3.1 小试牛刀
网络拓扑图中, 最重要的信息就是节点和互联线路,其他都为辅助信息
在官方文档中,已经有详细的说明可以增加节点(addnode)、增加连线(addlink);在这个两个功能中,还有其他的选项,可以补充增加,官方提供的方法,可以通过help 查看文档说明help(N2G.plugins.diagrams.N2G_DrawIO.drawio_diagram)
这里只需要重点查看Quick start部分增加节点和连接就可以了。
1 from N2G import drawio_diagram
2
3 diagram = drawio_diagram()#
4 diagram.add_diagram("Page-1")
5 diagram.add_node(id="R1")#增加节点
6 diagram.add_node(id="R2")#增加节点
7 diagram.add_link("R1", "R2", label="DF", src_label="Gi1/1", trgt_label="GE23")#增加节点之间的连线,标签名称,src_lable和trgt_lable 可以用来标注端口
8 diagram.layout(algo="kk")#图层,不重要
9 diagram.dump_file(filename="Sample_graph.drawio", folder="./Output/")#保存拓扑图
以上示例是官方最简单的画图程序,自己可以多增加几个节点进行练习。
但是在网络情况里,对每个邻居节点都登录检测检查邻居信息时,会遇到同一个连接,在两台设备上都能发现,那么创建节点和连接时会出现什么情况呢?
这里官方有说明,如果发现节点已经存在就直接跳过(也可以自定义),这样我们再写程序上就简单很多,链接里有说明。
3.2 完成程序输出
1 from N2G import drawio_diagram
2 import textfsm
3 import json
4 import telnetlib
5 import time
6
7
8 file_path = './host_1218.txt'
9 #主机IP清单,格式如下:
10 #cisco 192.168.1.1 cisco cisco
11
12
13 template_file = "./cisco_tfm.template"
14 style_cisco = "verticalLabelPosition=bottom;html=1;verticalAlign=top;aspect=fixed;align=center;pointerEvents=1;shape=mxgraph.cisco19.rect;prIcon=l2_switch;fillColor=#FAFAFA;strokeColor=#005073;"
15 # 图标格式
16
17 def data_format(ip_address,cdp_data):
18
19 hostname = cdp_data[0][0]#二层列表格式,获取主机名
20 result_data = {
21 ip_address: {
22 hostname: {item[1]: item[2:] for item in cdp_data}
23 }
24 }
25 json_data = json.dumps(result_data, indent=2)
26
27 return json_data
28 # return the JSON formatted string
29
30
31 def cisco_telent(ip, username, password, cmd):
32 # 创建Telnet连接
33 tn = telnetlib.Telnet(ip)
34 time.sleep(0.1)
35
36 tn.read_until(b"Username:")
37 tn.write(username.encode('ascii') + b"\n")
38
39 tn.read_until(b"Password: ")
40 tn.write(password.encode('ascii') + b"\n")
41 tn.write(b"terminal length 0\n")
42
43 tn.write(cmd.encode('ascii') + b"\n")
44
45 time.sleep(0.5)
46 tn.write(b"exit\n")
47 # # 读取输出并打印
48 output = tn.read_very_eager().decode('ascii')
49
50 tn.close() # 关闭连接
51 return output
52
53
54 diagram = drawio_diagram()
55 diagram.add_diagram("Page-1")
56
57 host_info_dict = {}
58
59 node_num = 0
60 #节点计数
61 # 打开文件进行读取
62 with open(file_path, 'r') as file:
63 for line in file:
64 # 分割每一行以获取主机信息
65 host_info = line.strip().split()
66
67 # 检查是否有足够的信息
68 if len(host_info) == 4:
69 device_type, ip, username, password = host_info
70
71 # 构建设备字典
72 device = {
73 'device_type': device_type,
74 'ip': ip,
75 'username': username,
76 'password': password,
77 }
78
79 try:
80 # 执行telnet
81
82 cmd = 'show cdp neighbors detail'
83
84 command_output = cisco_telent(ip, username, password, cmd)
85 with open(template_file) as template:
86 #打开模板,进行数据提取
87 fsm = textfsm.TextFSM(template)
88 result = fsm.ParseText(command_output)
89 #列表格式数据,需要进行转换
90
91 nei_info_format = data_format(ip,result)
92 # print(nei_info_format)
93 parsed_data = json.loads(nei_info_format)
94
95 for ip_address, inner_data in parsed_data.items():
96 for local_hostname, cdp_data in inner_data.items():
97 if local_hostname not in host_info_dict:
98 #节点不存在,进行创建节点并保存节点信息
99 diagram.add_node(id=ip_address,name= local_hostname, style =style_cisco, width=60, height=60)
100 #增加本机节点
101 node_num += 1
102 # print(ip_address, local_hostname)
103 host_info_dict[local_hostname] = ip_address
104 # print(host_info_dict) 节点主机名和IP信息保存,后续进行校验节点是否已经存在
105
106 for src_label, values in cdp_data.items():
107 nei_host_name, nei_host_module, nei_host_id, trgt_label = values
108 #如果邻居节点不存在,直接创建;如果节点已经存在,则邻居ID信息要更新,更换成已经存在节点的IP地址()
109 if nei_host_name not in host_info_dict:
110 diagram.add_node(id=nei_host_id,name=nei_host_name,style=style_cisco, width=60, height=60)
111 #根据邻居信息,增加邻居节点
112 host_info_dict[nei_host_name] = nei_host_id
113 print("Add node " + nei_host_id + "secuessed.")
114 node_num += 1
115 diagram.add_link(ip_address, nei_host_id, src_label=src_label, trgt_label=trgt_label)
116 else:
117 nei_host_id = host_info_dict[nei_host_name]
118 diagram.add_link(ip_address, nei_host_id, src_label=src_label, trgt_label=trgt_label)
119 else:
120 print('节点已存在:' + local_hostname + ip_address)
121 #节点存在,检查邻居信息,根据邻居信息进行判断,是否添加邻居节点
122 for src_label, values in cdp_data.items():
123 nei_host_name, nei_host_module, nei_host_id, trgt_label = values
124 if nei_host_name not in host_info_dict:
125 diagram.add_node(id=nei_host_id, name=nei_host_name, style=style_cisco, width=60, height=60)
126 #根据邻居信息,增加邻居节点
127 host_info_dict[nei_host_name] = nei_host_id
128 print("Add node " + nei_host_id + "secuessed.")
129 node_num += 1
130 diagram.add_link(ip_address, nei_host_id, src_label=src_label, trgt_label=trgt_label)
131 else:
132 nei_host_id = host_info_dict[nei_host_name]
133 diagram.add_link(ip_address, nei_host_id, src_label=src_label, trgt_label=trgt_label)
134
135 # print("Add node " + ip_address + " sucessed.")
136
137 except Exception as e:
138 print(f"Failed to connect to {ip}: {e}")
139
140 else:
141 print(f"Invalid line in the file: {line.strip()}")
142 print(node_num)
143 print(host_info_dict,len(host_info_dict))
144 diagram.dump_file(filename="Sample_campus_00.drawio", folder="./Output/")
draw_topology_N2G
以上脚本,除路径本人修改过以外,整个程序在网络环境中进行的验证。
说明:
1、在第57行,创建了1个字典,用来保存发现的邻居数据,主机名、主机名称,用来后续对新发现节点进行判断。为什么还需要进行判断?
因为当一台设备上有多个IP地址时,与之互联的设备邻居信息显示的IP信息可能是不一样的,所以再次通过主机名再次进行判断;当然这里也不是很严谨,因为设备名称可能存在全局不唯一的情况,所以在cisco NX-OS中,CDP邻居信息会显示设备的序列号,这样就避免前面的情况。
2、因为网络规模较大,输出的拓扑文件也比较大,所以在第59行,增加了一个计数,在每增加1个节点,都进行一个保存信息,最终输出看有多少网络设备。
3、为什么add_node 方法中有非官方说明的字段"name".
答:非标准字段,生成的拓扑图会以属性字段描述节点,鼠标放到节点上就可显示,不会直接显示出来,包括前面已经提取到的设备型号,也可以通过增加字段module在拓扑图中隐性的展示;右键成编辑节点数据,即可查看或编辑数据
四、因为在程序中没有指定每个节点的坐标位置,所以生成的拓扑图,所有的图标节点都是在默认位置,所以会出现重叠的情况,只需要在调整图形-布局,选择"垂直流"就可自动重新排列。