Documentation
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Overview ¶
Package roce decodes the InfiniBand Base Transport Header (BTH) of RoCE — RDMA over Converged Ethernet — the datacenter Remote Direct Memory Access fabric. RoCEv2 carries the InfiniBand transport over UDP (destination port 4791), letting one host read and write another host's memory directly, bypassing the remote CPU. It is the fabric under high-performance storage (NVMe-oF), GPU clusters (NCCL / GPUDirect) and HPC. RDMA is a real and often-overlooked attack surface: the wire protocol is unencrypted and unauthenticated by default, isolation rests only on the 16-bit Partition Key (P_Key) and the Queue-Pair number, and an attacker on the fabric who can forge a BTH can issue RDMA READ / WRITE operations against a remote host's registered memory regions. A captured RoCE BTH identifies the **RDMA operation** in flight — an RDMA READ / WRITE (direct remote memory access), an atomic compare-swap / fetch-add, a SEND, an ACK or a congestion-notification (CNP) — together with the **destination Queue Pair**, the **Partition Key** (the fabric isolation domain) and the packet sequence number, which is the recon headline for RDMA-fabric reconnaissance. It is the InfiniBand transport member of the project's network-decoder family, a distinct domain.
Wrap-vs-native judgement ¶
Native. The BTH is a fixed 12-byte header — a byte opcode + a handful of bit-fields (flags, P_Key, a 24-bit destination QP, a 24-bit PSN). A byte/bit read + an opcode lookup; stdlib only, no new go.mod dep.
Verifiable / no confidently-wrong output ¶
The 12-byte BTH layout and the 57-entry opcode table were verified field-for-field against scapy's RoCE layer (scapy.contrib.roce). The opcode name table is code-generated from scapy's authoritative map (not hand-transcribed). Only the always-present BTH is decoded: the per-opcode extended transport headers (RETH for RDMA, AETH for ACKs, AtomicETH, the ImmDt / immediate data) and the payload vary by opcode and are surfaced as raw hex — the trailing 4 bytes are the ICRC. The transport-service type is derived from the opcode's top three bits per the IBA spec; an opcode outside the known table is reported by value with a note rather than guessed.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Result ¶
type Result struct {
Opcode int `json:"opcode"`
OpcodeHex string `json:"opcode_hex"`
OpcodeName string `json:"opcode_name"`
TransportService string `json:"transport_service"`
Solicited bool `json:"solicited"`
MigReq bool `json:"mig_req"`
PadCount int `json:"pad_count"`
HeaderVersion int `json:"header_version"`
PKey string `json:"p_key"`
FECN bool `json:"fecn"`
BECN bool `json:"becn"`
DestQP string `json:"dest_qp"`
AckReq bool `json:"ack_req"`
PSN int `json:"psn"`
PayloadHex string `json:"payload_hex,omitempty"`
Notes []string `json:"notes,omitempty"`
}
Result is the decoded view of a RoCE InfiniBand Base Transport Header.
Source Files