public PDU(UdpDatagram datagram)
{
_udp = datagram;
MemoryStream stream = new MemoryStream(datagram.UdpData);
BasicEncodingReader _reader = new BasicEncodingReader(stream);
Asn1Type seqType = _reader.ReadType();
int seqLength = _reader.ReadLength();
Version = _reader.ReadInteger();
Community = _reader.ReadOctetString();
Asn1Type t = _reader.ReadType();
PduType = (PduType)(t.Byte & 0x1F);
if (PduType == Snmp.PduType.Trap)
{
throw new NotImplementedException("SNMP v1 traps are not yet implemented");
}
int len = _reader.ReadLength();
RequestId = _reader.ReadInteger();
ErrorStatus = _reader.ReadInteger();
ErrorIndex = _reader.ReadInteger();
Asn1Type type = _reader.ReadType();
if (type.Class != Asn1Class.Universal && type.Tag != Asn1Tag.Sequence)
{
throw new Exception("Sequence expected");
}
int length = _reader.ReadLength();
VarBinds = new SortedDictionary <string, object>();
var list = _reader.ReadConstructedType(length);
foreach (List <object> seq in list)
{
string oid = (string)seq[0];
VarBinds.Add(oid, seq[1]);
}
}
static void Asn1Encoding()
{
Console.WriteLine("\n======================= {0} =======================\n", MethodInfo.GetCurrentMethod().Name);
var packets = PcapNg.ReadForward(fileName)
.Where(b => b.Type == BlockType.EnhancedPacketBlock)
.Cast <EnhancedPacketBlock>()
.Take(5);
foreach (var packet in packets)
{
int snmpLen = packet.PacketData.Length - 42; // 42 is the size of Ethernet + IP + UDP headers
byte[] datagram = new byte[snmpLen];
Array.Copy(packet.PacketData, 42, datagram, 0, snmpLen);
Console.WriteLine(BasicEncodingReader.ReadAllText(datagram));
}
}
