下面的例子是通过SNMP获取指定IP的机器名。
using System;
using System.Text;
using System.Net;
using System.Net.Sockets;namespace ConsoleSNMP
{
public class Program
{
static void Main()
{
string host = "192.168.1.1";
string communityName = "public";
SNMP conn
= new SNMP();
byte[] response = new byte[1024]; Console.WriteLine(
"Device SNMP information:"); response
= conn.get("GetRequest", host, communityName, "1.3.6.1.2.1.1.5.0");
if (response[0] == 0xff)
{
Console.WriteLine("No response from {0}", host);
return;
}int commlength = Convert.ToInt16(response[6]);
int miblength = Convert.ToInt16(response[23 + commlength]);int datatype = Convert.ToInt16(response[24 + commlength + miblength]);
int datalength = Convert.ToInt16(response[25 + commlength + miblength]);
int datastart = 26 + commlength + miblength;
string output = Encoding.ASCII.GetString(response, datastart, datalength);
Console.WriteLine(" 机器名: - Datatype: {0}, Value: {1}",
datatype, output); Console.ReadLine();
}
}
class SNMP
{
public byte[] get(string request, string host, string community, string mibstring)
{
byte[] packet = new byte[1024];
byte[] mib = new byte[1024];
int snmplen;
int comlen = community.Length;
string[] mibvals = mibstring.Split('.');
int miblen = mibvals.Length;
int cnt = 0, temp=0, i=0;
int orgmiblen = miblen;
int pos = 0;//将mib字符串格式转换为整数格式，如果值大于128需要多个字节空间保存，同时增加mib库的长度
for (i = 0; i < orgmiblen; i++)
{
temp = Convert.ToInt16(mibvals[i]);
if (temp > 127)
{
mib[cnt] = Convert.ToByte(128 + (temp / 128));
mib[cnt + 1] = Convert.ToByte(temp - ((temp / 128) * 128));
cnt += 2;
miblen++;
}
else
{
mib[cnt] = Convert.ToByte(temp);
cnt++;
}
} snmplen
= 29 + comlen + miblen - 1;//snmp包序列开始
packet[pos++] = 0x30;
packet[pos++] = Convert.ToByte(snmplen - 2);//snmp版本号
packet[pos++] = 0x02;//整数类型
packet[pos++] = 0x01;//长度
packet[pos++] = 0x01;//snmp 版本1//团体名称
packet[pos++] = 0x04;//字符串类型
packet[pos++] = Convert.ToByte(comlen);//团体名称长度
byte[] data = Encoding.ASCII.GetBytes(community);
for (i = 0; i < data.Length; i++)
{
packet[pos++] = data[i];//转化团体名称到包中
}//添加GetRequest 或是GetNextRequest 值
if (request == "GetRequest")
{
packet[pos++] = 0xA0;
}
else
{
packet[pos++] = 0xA1;
} packet[pos
++] = Convert.ToByte(20 + miblen - 1);//Request ID
packet[pos++] = 0x02;//整数类型
packet[pos++] = 0x04;//长度
packet[pos++] = 0x00;//SNMP request ID
packet[pos++] = 0x00;
packet[pos++] = 0x00;
packet[pos++] = 0x01;//错误状态
packet[pos++] = 0x02;//整数类型
packet[pos++] = 0x01;//长度
packet[pos++] = 0x00;//SNMP错误类型//错误索引
packet[pos++] = 0x02;//整数类型
packet[pos++] = 0x01;//长度
packet[pos++] = 0x00;//SNMP错误索引
packet[pos++] = 0x30;//不同对象序列开始标志
packet[pos++] = Convert.ToByte(6 + miblen - 1);//不同对象的长度
packet[pos++] = 0x30;//对象序列的开始
packet[pos++] = Convert.ToByte(6 + miblen - 1 - 2);//尺寸
packet[pos++] = 0x06;//对象类型
packet[pos++] = Convert.ToByte(miblen - 1);//长度//MIB信息开始位置
packet[pos++] = 0x2b;
//把MIB数字放入包中
for (i = 2; i < miblen; i++)
{
packet[pos++] = Convert.ToByte(mib[i]);
}
packet[pos++] = 0x05;//空对象值
packet[pos++] = 0x00;//空//通过Socket把包送到指定机器
Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 5000);
IPHostEntry ihe = Dns.Resolve(host);
IPEndPoint iep = new IPEndPoint(ihe.AddressList[0], 161);
EndPoint ep = (EndPoint)iep;
sock.SendTo(packet, snmplen, SocketFlags.None, iep);try
{
int recv = sock.ReceiveFrom(packet, ref ep);//接受返回数据
}
catch (SocketException)
{
packet[0] = 0xff;
}return packet;
}
}
}运行结果如下图：
