C#简单实现SNMP的方法

本文实例讲述了C#简单实现SNMP的方法。分享给大家供大家参考。具体如下：

/**
C# Network Programming
by Richard Blum
Publisher: Sybex
ISBN: 0782141765
*/
using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
public class SimpleSNMP
{
 public static void Main(string[] argv)
 {
  int commlength, miblength, datatype, datalength, datastart;
  int uptime = 0;
  string output;
  SNMP conn = new SNMP();
  byte[] response = new byte[1024];
  Console.WriteLine("Device SNMP information:");
  // Send sysName SNMP request
  response = conn.get("get", argv[0], argv[1], "1.3.6.1.2.1.1.5.0");
  if (response[0] == 0xff)
  {
    Console.WriteLine("No response from {0}", argv[0]);
    return;
  }
  // If response, get the community name and MIB lengths
  commlength = Convert.ToInt16(response[6]);
  miblength = Convert.ToInt16(response[23 + commlength]);
  // Extract the MIB data from the SNMP response
  datatype = Convert.ToInt16(response[24 + commlength + miblength]);
  datalength = Convert.ToInt16(response[25 + commlength + miblength]);
  datastart = 26 + commlength + miblength;
  output = Encoding.ASCII.GetString(response, datastart, datalength);
  Console.WriteLine(" sysName - Datatype: {0}, Value: {1}",
      datatype, output);
  // Send a sysLocation SNMP request
  response = conn.get("get", argv[0], argv[1], "1.3.6.1.2.1.1.6.0");
  if (response[0] == 0xff)
  {
    Console.WriteLine("No response from {0}", argv[0]);
    return;
  }
  // If response, get the community name and MIB lengths
  commlength = Convert.ToInt16(response[6]);
  miblength = Convert.ToInt16(response[23 + commlength]);
  // Extract the MIB data from the SNMP response
  datatype = Convert.ToInt16(response[24 + commlength + miblength]);
  datalength = Convert.ToInt16(response[25 + commlength + miblength]);
  datastart = 26 + commlength + miblength;
  output = Encoding.ASCII.GetString(response, datastart, datalength);
  Console.WriteLine(" sysLocation - Datatype: {0}, Value: {1}", datatype, output);
  // Send a sysContact SNMP request
  response = conn.get("get", argv[0], argv[1], "1.3.6.1.2.1.1.4.0");
  if (response[0] == 0xff)
  {
    Console.WriteLine("No response from {0}", argv[0]);
    return;
  }
  // Get the community and MIB lengths
  commlength = Convert.ToInt16(response[6]);
  miblength = Convert.ToInt16(response[23 + commlength]);
  // Extract the MIB data from the SNMP response
  datatype = Convert.ToInt16(response[24 + commlength + miblength]);
  datalength = Convert.ToInt16(response[25 + commlength + miblength]);
  datastart = 26 + commlength + miblength;
  output = Encoding.ASCII.GetString(response, datastart, datalength);
  Console.WriteLine(" sysContact - Datatype: {0}, Value: {1}",
      datatype, output);
  // Send a SysUptime SNMP request
  response = conn.get("get", argv[0], argv[1], "1.3.6.1.2.1.1.3.0");
  if (response[0] == 0xff)
  {
    Console.WriteLine("No response from {0}", argv[0]);
    return;
  }
  // Get the community and MIB lengths of the response
  commlength = Convert.ToInt16(response[6]);
  miblength = Convert.ToInt16(response[23 + commlength]);
  // Extract the MIB data from the SNMp response
  datatype = Convert.ToInt16(response[24 + commlength + miblength]);
  datalength = Convert.ToInt16(response[25 + commlength + miblength]);
  datastart = 26 + commlength + miblength;
  // The sysUptime value may by a multi-byte integer
  // Each byte read must be shifted to the higher byte order
  while(datalength > 0)
  {
    uptime = (uptime << 8) + response[datastart++];
    datalength--;
  }
  Console.WriteLine(" sysUptime - Datatype: {0}, Value: {1}",
      datatype, uptime);
 }
}
class SNMP
{
 public 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, i;
  int orgmiblen = miblen;
  int pos = 0;
  // Convert the string MIB into a byte array of integer values
  // Unfortunately, values over 128 require multiple bytes
  // which also increases the MIB length
  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; //Length of entire SNMP packet
  //The SNMP sequence start
  packet[pos++] = 0x30; //Sequence start
  packet[pos++] = Convert.ToByte(snmplen - 2); //sequence size
  //SNMP version
  packet[pos++] = 0x02; //Integer type
  packet[pos++] = 0x01; //length
  packet[pos++] = 0x00; //SNMP version 1
  //Community name
  packet[pos++] = 0x04; // String type
  packet[pos++] = Convert.ToByte(comlen); //length
  //Convert community name to byte array
  byte[] data = Encoding.ASCII.GetBytes(community);
  for (i = 0; i < data.Length; i++)
  {
    packet[pos++] = data[i];
  }
  //Add GetRequest or GetNextRequest value
  if (request == "get")
    packet[pos++] = 0xA0;
  else
    packet[pos++] = 0xA1;
  packet[pos++] = Convert.ToByte(20 + miblen - 1); //Size of total MIB
  //Request ID
  packet[pos++] = 0x02; //Integer type
  packet[pos++] = 0x04; //length
  packet[pos++] = 0x00; //SNMP request ID
  packet[pos++] = 0x00;
  packet[pos++] = 0x00;
  packet[pos++] = 0x01;
  //Error status
  packet[pos++] = 0x02; //Integer type
  packet[pos++] = 0x01; //length
  packet[pos++] = 0x00; //SNMP error status
  //Error index
  packet[pos++] = 0x02; //Integer type
  packet[pos++] = 0x01; //length
  packet[pos++] = 0x00; //SNMP error index
  //Start of variable bindings
  packet[pos++] = 0x30; //Start of variable bindings sequence
  packet[pos++] = Convert.ToByte(6 + miblen - 1); // Size of variable binding
  packet[pos++] = 0x30; //Start of first variable bindings sequence
  packet[pos++] = Convert.ToByte(6 + miblen - 1 - 2); // size
  packet[pos++] = 0x06; //Object type
  packet[pos++] = Convert.ToByte(miblen - 1); //length
  //Start of MIB
  packet[pos++] = 0x2b;
  //Place MIB array in packet
  for(i = 2; i < miblen; i++)
    packet[pos++] = Convert.ToByte(mib[i]);
  packet[pos++] = 0x05; //Null object value
  packet[pos++] = 0x00; //Null
  //Send packet to destination
  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);
  //Receive response from packet
  try
  {
    int recv = sock.ReceiveFrom(packet, ref ep);
  } catch (SocketException)
  {
    packet[0] = 0xff;
  }
  return packet;
 }
 public string getnextMIB(byte[] mibin)
 {
  string output = "1.3";
  int commlength = mibin[6];
  int mibstart = 6 + commlength + 17; //find the start of the mib section
  //The MIB length is the length defined in the SNMP packet
  // minus 1 to remove the ending .0, which is not used
  int miblength = mibin[mibstart] - 1;
  mibstart += 2; //skip over the length and 0x2b values
  int mibvalue;
  for(int i = mibstart; i < mibstart + miblength; i++)
  {
    mibvalue = Convert.ToInt16(mibin[i]);
    if (mibvalue > 128)
    {
     mibvalue = (mibvalue/128)*128 + Convert.ToInt16(mibin[i+1]);
     //ERROR here, it should be mibvalue = (mibvalue-128)*128 + Convert.ToInt16(mibin[i+1]);
     //for mib values greater than 128, the math is not adding up correctly  
     i++;
    }
    output += "." + mibvalue;
  }
  return output;
 }
}

希望本文所述对大家的C#程序设计有所帮助。