maccontrol

Overview ¶

Package maccontrol decodes IEEE 802.3 MAC Control frames (EtherType 0x8808) — the Ethernet flow-control and EPON access-control sublayer. Its two flow-control opcodes are recognised L2 denial-of-service surfaces and so join the project's L2-attack decoder family (internal/dtp, vtp, vqp, gxrp, stp):

• PAUSE (802.3x, opcode 0x0001): a frame to 01:80:c2:00:00:01 tells the upstream port to stop sending for pause_time × 512 bit-times. A flood of PAUSE frames with the maximum quanta (0xFFFF) is the classic switch-port flow-control DoS — it can stall the port indefinitely.
• PFC / Priority-based Flow Control (802.1Qbb, opcode 0x0101): the per-priority version used in lossless datacenter fabrics (RoCE / FCoE); a PFC storm causes head-of-line blocking and can collapse a converged fabric.

The remaining opcodes are EPON MPCP (Multi-Point Control Protocol): GATE / REPORT / REGISTER_REQ / REGISTER / REGISTER_ACK, the time-slot grant + discovery handshake of an Ethernet PON.

Wrap-vs-native judgement ¶

Native. A MAC Control frame is a 2-byte opcode followed by a small
fixed, opcode-specific body (a pause time, a PFC class-enable vector
+ eight times, or an MPCP timestamp + fields). A byte-field read +
an opcode switch; stdlib only, no new go.mod dep.

Verifiable / no confidently-wrong output ¶

Every opcode body was verified field-for-field against scapy's
MACControl layer (scapy.contrib.mac_control). MAC Control frames are
padded to the 60-byte minimum Ethernet payload; the decoder reads
only the defined opcode fields and reports any non-zero trailing
bytes rather than guessing at them. An unknown opcode is named by
number with its body surfaced as raw hex.