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。