//
// The Maximum Buffer assumes every unknown length requires 5 octets
//
public static UInt32 MaximumBufferForSet(UInt32 communityLength, UInt32 oidLength, UInt32 valueAsnLength)
{
return
(1U + 5U + // SNMP Sequence
3U + // Version
1U + // Community
Asn1.DefiniteLengthOctetCount(communityLength) +
communityLength +
1U + 5U + // PDU Type
2U + 5U + // Request ID
3U + // Error Status
3U + // Error Index
1U + 5U + // Varbind List
1U + 5U + // Varbind
1U + // Oid
Asn1.DefiniteLengthOctetCount(oidLength) +
oidLength +
valueAsnLength); // Value
}
public static UInt32 SerializeSnmp(Byte[] packet, UInt32 offset, String community, Byte pduAsnType,
Int32 requestID, IList <Byte> oid, IList <Byte> asnValue)
{
//
// Calculate lengths
//
UInt32 varbindLength =
1U + Asn1.DefiniteLengthOctetCount((UInt32)oid.Count) + (UInt32)oid.Count + // Oid
(UInt32)asnValue.Count; // Value
UInt32 varbindListLength =
1U + Asn1.DefiniteLengthOctetCount(varbindLength) + varbindLength; // Varbind
UInt32 pduLength =
2U + Asn1.IntegerOctetCount(requestID) + // Request ID
3U + // Error Status
3U + // Error Index
1U + Asn1.DefiniteLengthOctetCount(varbindListLength) + varbindListLength; // VarbindList
UInt32 snmpSequenceLength =
3U + // Version
1U + Asn1.IntegerOctetCount(community.Length) + (UInt32)community.Length + // Comunity
1U + Asn1.DefiniteLengthOctetCount(pduLength) + pduLength; // Pdu
//
// TODO: check that packet is large enough
//
//
// SNMP Message Type
//
packet[offset++] = Asn1.TYPE_SEQUENCE;
offset = packet.SetInteger(offset, snmpSequenceLength);
//
// Version
//
packet[offset++] = Asn1.TYPE_INTEGER;
packet[offset++] = 1;
packet[offset++] = 0; // Version 1
//
// Community
//
packet[offset++] = Asn1.TYPE_OCTET_STRING;
offset = packet.SetInteger(offset, (UInt32)community.Length);
for (int i = 0; i < community.Length; i++)
{
packet[offset++] = (Byte)community[i];
}
//
// PDU Type
//
packet[offset++] = pduAsnType;
offset = packet.SetInteger(offset, pduLength);
//
// Request ID
//
packet[offset++] = Asn1.TYPE_INTEGER;
Byte requestIDOctetCount = Asn1.IntegerOctetCount(requestID);
packet[offset++] = requestIDOctetCount;
offset = Asn1.SetInteger(packet, offset, requestID);
//
// Error Status
//
packet[offset++] = Asn1.TYPE_INTEGER;
packet[offset++] = 1;
packet[offset++] = 0;
//
// Error Index
//
packet[offset++] = Asn1.TYPE_INTEGER;
packet[offset++] = 1;
packet[offset++] = 0;
//
// Variable Bindings
//
packet[offset++] = Asn1.TYPE_SEQUENCE;
offset = packet.SetInteger(offset, varbindListLength);
//
// Varbind
//
packet[offset++] = Asn1.TYPE_SEQUENCE;
offset = packet.SetInteger(offset, varbindLength);
// OID
packet[offset++] = Asn1.TYPE_OBJECT_ID;
offset = packet.SetInteger(offset, (UInt32)oid.Count);
for (Int32 i = 0; i < oid.Count; i++)
{
packet[offset++] = oid[i];
}
// Value
for (int i = 0; i < asnValue.Count; i++)
{
packet[offset++] = asnValue[i];
}
return(offset);
}
static Int32 Main(String[] args)
{
Options options = new Options();
List <String> nonOptionArgs = options.Parse(args);
if (nonOptionArgs.Count == 0)
{
options.PrintUsage();
return(1);
}
String command = nonOptionArgs[0];
if (nonOptionArgs.Count < 3)
{
return(options.ErrorAndUsage("Error: Missing command line arguments"));
}
String hostString = nonOptionArgs[1];
String oidString = nonOptionArgs[2];
IPEndPoint endPoint = EndPoints.ParseIPOrResolveHostWithOptionalPort(hostString, 161, DnsPriority.IPv4ThenIPv6);
List <Byte> oidBytes = new List <Byte>();
Snmp.ParseOid(oidString, oidBytes);
Byte[] oid = oidBytes.ToArray();
if (command.Equals("get", StringComparison.CurrentCultureIgnoreCase))
{
if (nonOptionArgs.Count != 3)
{
return(options.ErrorAndUsage("Error: operation 'get' requires 2 arguments but there are {0}", nonOptionArgs.Count - 1));
}
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
Byte[] packet = new Byte[Snmp.MaximumBufferForGet(
(UInt32)options.community.ArgValue.Length, (UInt32)oid.Length)];
UInt32 snmpContentLength = Snmp.SerializeGet(packet, 0, options.community.ArgValue, Snmp.NextID(), oid);
socket.SendTo(packet, (Int32)snmpContentLength, 0, endPoint);
}
else if (command.Equals("set", StringComparison.CurrentCultureIgnoreCase))
{
if (nonOptionArgs.Count != 5)
{
return(options.ErrorAndUsage("Error: operation 'set' requires 4 arguments but there are {0}", nonOptionArgs.Count - 1));
}
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
Byte[] value = Asn1.ParseValue(nonOptionArgs[3], nonOptionArgs[4]);
Byte[] packet = new Byte[Snmp.MaximumBufferForSet(
(UInt32)options.community.ArgValue.Length, (UInt32)oid.Length, (UInt32)value.Length)];
UInt32 snmpContentLength = Snmp.SerializeSet(packet, 0, options.community.ArgValue, Snmp.NextID(), oid, value);
socket.SendTo(packet, (Int32)snmpContentLength, 0, endPoint);
}
else
{
Console.WriteLine("Error: Unknown operation '{0}'", command);
return(1);
}
return(0);
}