Patch Set Summary: Industrial Protocol Support (CIP, Ethernet/IP)

Overview

This patch set ports the changes from google/gopacket PR #758 to add support for industrial automation protocols: CIP (Common Industrial Protocol), and ENIP (Ethernet/IP).

New Protocol Implementations

1. CIP (Common Industrial Protocol)

File: layers/cip.go

• Purpose: Application-layer protocol used in industrial automation
• Key Features:
  • Service code definitions (GetAttributesAll, SetAttributesAll, GetAttributeSingle, SetAttributeSingle, MultipleServicePacket)
  • Status code handling (Success, ConnectionFailure, ResourceUnavailable, etc.)
  • Path segment parsing for Class ID, Instance ID, and Attribute ID
  • Request/Response differentiation
  • Full decoder implementation following gopacket patterns

2. ENIP (Ethernet/IP)

File: layers/enip.go

• Purpose: Ethernet encapsulation protocol for CIP
• Key Features:
  • 24-byte header parsing
  • Command codes (NOP, ListServices, RegisterSession, UnregisterSession, SendRRData, SendUnitData, etc.)
  • Status code handling
  • Session management fields (SessionHandle, SenderContext)
  • Automatic CIP payload decoding for SendRRData and SendUnitData commands
  • Serialization support
  • Little-endian encoding (as per ENIP specification)

Modified Files

Core Layer Registration

layers/layertypes.go

• Added LayerTypeENIP (ID: 151)
• Added LayerTypeCIP (ID: 152)

LayerTypeENIP = gopacket.RegisterLayerType(151, gopacket.LayerTypeMetadata{
    Name: "ENIP", 
    Decoder: gopacket.DecodeFunc(decodeENIP)
})
LayerTypeCIP = gopacket.RegisterLayerType(152, gopacket.LayerTypeMetadata{
    Name: "CIP", 
    Decoder: gopacket.DecodeFunc(decodeCIP)
})

layers/ports.go

Added port mappings for automatic protocol detection:

TCP Ports:

• Port 2222 → LayerTypeENIP (EtherNet/IP-1)
• Port 44818 → LayerTypeENIP (EtherNet/IP-2)

UDP Ports:

• Port 2222 → LayerTypeENIP (EtherNet/IP-1)
• Port 44818 → LayerTypeENIP (EtherNet/IP-2)

layers/enums.go

• Added missing errors import
• Added EthernetTypeERSPAN constant (0x88be)
• Added EthernetTypeRaw constant (0xFFFF)

Protocol Specifications

Port Numbers

Layer Hierarchy

Ethernet
  └── IPv4/IPv6
      └── TCP/UDP
          └── ENIP (ports 2222, 44818)
              └── CIP (for SendRRData/SendUnitData commands)
                  └── Payload

Credits

• Original implementation by @traetox in PR #408
• Reimplemented by @dreadl0ck in PR #758
• Ported to gopacket-community repository

References

• CIP: ODVA Common Industrial Protocol specification
• ENIP: ODVA Ethernet/IP specification
• IANA Ports: Port 2222 (EtherNet-IP-1), Port 44818 (EtherNet-IP-2)