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。
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