/// <summary> /// Attempts to parse raw data into a structured packet /// </summary> /// <param name="buffer">Raw data to parse</param> /// <param name="packet">Parsed packet</param> /// <param name="count">The length of the packet in bytes</param> /// <param name="index">The index into the buffer at which the packet begins</param> /// <returns>True if parsing was successful, false if it is not.</returns> internal static bool TryParse(byte[] buffer, int index, int count, out SNAP packet) { try { if (count < MinimumParseableBytes) { packet = null; return(false); } using (var ms = new MemoryStream(buffer, index, count, false)) { using (var br = new BinaryReader(ms)) { var organizationCode = br.ReadBytes(3); var etherType = ByteOrder.NetworkToHostOrder(br.ReadUInt16()); packet = null; if (organizationCode[0] == 0 && organizationCode[1] == 0 && organizationCode[2] == 0) { switch (etherType) { case (ushort)EtherTypes.IPv4: { IPv4 payload; if (IPv4.TryParse( buffer, index + (int)br.BaseStream.Position, (int)(count - br.BaseStream.Position), out payload)) { packet = new SNAP <IPv4> { Payload = payload }; } } break; case (ushort)EtherTypes.ARP: { ARP payload; if (ARP.TryParse( buffer, index + (int)br.BaseStream.Position, (int)(count - br.BaseStream.Position), out payload)) { packet = new SNAP <ARP> { Payload = payload }; } } break; case (ushort)EtherTypes.EAPoLAN: { IEEE802_1x payload; if (IEEE802_1x.TryParse( buffer, index + (int)br.BaseStream.Position, (int)(count - br.BaseStream.Position), out payload)) { packet = new SNAP <IEEE802_1x> { Payload = payload }; } } break; } } if (packet == null) { Generic payload; Generic.TryParse( buffer, index + (int)br.BaseStream.Position, (int)(count - br.BaseStream.Position), out payload); // This can never fail, so I'm not checking the output packet = new SNAP <Generic> { Payload = payload }; } packet.OrganizationCode = organizationCode; packet.ProtocolID = etherType; return(true); } } } catch (Exception) { packet = null; return(false); } }
/// <summary> /// Attempts to parse raw data into a structured packet /// </summary> /// <param name="buffer">Raw data to parse</param> /// <param name="packet">Parsed packet</param> /// <param name="count">The length of the packet in bytes</param> /// <param name="index">The index into the buffer at which the packet begins</param> /// <returns>True if parsing was successful, false if it is not.</returns> internal static bool TryParse(byte[] buffer, int index, int count, out EthernetII packet) { try { if (count < MinimumParseableBytes) { packet = null; return(false); } using (var ms = new MemoryStream(buffer, index, count, false)) { using (var br = new BinaryReader(ms)) { var dstMac = br.ReadBytes(6); var srcMac = br.ReadBytes(6); var etherType = ByteOrder.NetworkToHostOrder(br.ReadUInt16()); packet = null; switch (etherType) { case (ushort)EtherTypes.IPv4: { IPv4 payload; if (IPv4.TryParse( buffer, index + (int)br.BaseStream.Position, (int)(count - br.BaseStream.Position), out payload)) { packet = new EthernetII <IPv4> { Payload = payload }; } } break; case (ushort)EtherTypes.ARP: { ARP payload; if (ARP.TryParse( buffer, index + (int)br.BaseStream.Position, (int)(count - br.BaseStream.Position), out payload)) { packet = new EthernetII <ARP> { Payload = payload }; } } break; } if (packet == null) { Generic payload; Generic.TryParse( buffer, index + (int)br.BaseStream.Position, (int)(count - br.BaseStream.Position), out payload); // This can never fail, so I'm not checking the output packet = new EthernetII <Generic> { Payload = payload }; } packet.DstMac = dstMac; packet.EtherType = etherType; packet.SrcMac = srcMac; return(true); } } } catch (Exception) { packet = null; return(false); } }