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gspivey merged 2 commits into from
May 21, 2026
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Encap: IPv6 outer #60

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28febfd
feat(encap): add IPv6 outer support for GUE, VXLAN, GENEVE
May 21, 2026
c84e410
docs: append perf Run #25 results, mark Encap: IPv6 outer done in roa…
May 21, 2026
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4 changes: 2 additions & 2 deletions README.md
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Expand Up @@ -451,6 +451,8 @@ Integration testing runs on **AWS EC2 with VPC networking**, which has specific

**GENEVE endpoint (RFC 8926)** — Modern overlay tunnel: outer Ethernet + outer IPv4 + outer UDP (dst port 6081) + variable-length GENEVE header (24-bit VNI + TLV options up to 252 bytes) + inner Ethernet frame. Same frame shape as VXLAN plus extensible metadata — used by OVN, NSX-T, and AWS Gateway Load Balancer. Configurable per-socket via `set_geneve(Some(GeneveConfig::new(remote_ip, vni)))` or through `NetworkConfig::with_geneve()` on the builder. TX encapsulates transparently — the application calls `send_to(payload, inner_dst)` and the library wraps in the GENEVE tunnel automatically. RX decapsulates matching frames (VNI filter) and returns the inner source address to the application. TLV options are parsed on RX and available via the `GeneveHeader` in decap results. Ships with IPv4 outer; IPv6 outer is added by the "Encap: IPv6 outer" roadmap item. 43 tests (36 unit + 7 integration) including a synthetic PPS benchmark measuring GENEVE build+decap overhead.

**Encap: IPv6 outer** — IPv6 outer support for all three encapsulation protocols (VXLAN, GENEVE, GUE). Each protocol gains `build_*_frame_into_v6()` and `try_decap_*_v6()` functions using outer IPv6 headers with mandatory UDP6 checksum (RFC 8200 §8.1). New `*Config6` structs with `Ipv6Addr`, `*DecapResult6` types, and `*_ENCAP_OVERHEAD_V6` constants. Wire format: `[Outer Eth 14B][Outer IPv6 40B][Outer UDP 8B][Protocol Header][Inner frame]`. 41 unit tests including synthetic PPS benchmarks. *(PR [#60](https://github.com/gspivey/dpdk-stdlib-rust/pull/60))*

### Planned

Each bullet below is a standalone, one-PR-sized deliverable unless noted otherwise. IPv6 is a multi-PR feature with a sub-task checklist; it only moves to Done when every box is ticked and a final performance run shows no regression vs the IPv4 baseline.
Expand All @@ -467,8 +469,6 @@ Each bullet below is a standalone, one-PR-sized deliverable unless noted otherwi
- [x] **8. ICMPv6 error handling** — Destination Unreachable, Packet Too Big (with Next-Hop MTU), Time Exceeded, and Parameter Problem parsed and matched back to the originating socket. Plugs into the existing per-socket error queue (introduced for IPv4 ICMP errors) so `take_error()` works for IPv6 destinations too. *(PR [#58](https://github.com/gspivey/dpdk-stdlib-rust/pull/58), 24 tests)*
- [ ] **9. Performance tests** — TRex PPS run at 64 / 512 / 1400B, plus the synthetic CPU-only benchmark, compared against the IPv4 baseline. Results posted to `docs/perf-test-log.md`. No PPS regression vs IPv4 required to cross off the IPv6 feature.

**Encap: IPv6 outer** — Adds IPv6 outer support to all three encapsulation protocols (VXLAN, GENEVE, GUE), closing out dual-stack encap in a single PR. Depends on IPv6 tasks 1 (header build/parse), 2 (UDP pseudo-header checksum), and 4 (offload flags). Does NOT require NDP or ICMPv6 — only the wire-format subset of IPv6.

### Not Currently Planned

These are features the Linux kernel provides that we intentionally defer to the network infrastructure or consider out of scope:
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89 changes: 89 additions & 0 deletions docs/perf-test-log.md
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Expand Up @@ -5,6 +5,95 @@ Each entry captures the git context, test configuration, results, and analysis.

**Standard benchmarks** (include in every run entry):
1. **Hardware PPS** — TRex on c6in.xlarge (measures NIC + DPDK + application stack)

## Run #25: Encap IPv6 Outer (GUE, VXLAN, GENEVE) — No Regression

| Field | Value |
|-------|-------|
| **Date** | 2026-05-21 |
| **Git Hash** | `28febfd` |
| **Branch** | `agent/encap-ipv6-outer` |
| **PR** | [#60](https://github.com/gspivey/dpdk-stdlib-rust/pull/60) |
| **GH Actions Run** | [26204734648](https://github.com/gspivey/dpdk-stdlib-rust/actions/runs/26204734648) |
| **Instance Type** | c6in.xlarge (4 vCPU, 6.25 Gbps baseline / 30 Gbps burst) |
| **Traffic Generator** | TRex |

### Changes Since Run #18

1. **`28febfd` — IPv6 outer support for GUE, VXLAN, GENEVE.** Adds `build_*_frame_into_v6()` and `try_decap_*_v6()` functions for all three encap protocols, using outer IPv6 headers with mandatory UDP6 checksum (RFC 8200 §8.1). New `*Config6`, `*DecapResult6`, and `*_ENCAP_OVERHEAD_V6` types/constants. 41 new unit tests including synthetic PPS benchmarks. This is purely additive — zero changes to the existing IPv4 encap or plain UDP hot paths.

### Results: Hardware (TRex)

#### 64-byte packets

| Target PPS | rust-dpdk RX | Drop | Kernel RX | Drop | native-dpdk RX | Drop |
|-----------|-------------|------|----------|------|---------------|------|
| 70,000 | 69,000 | 1.4% | 69,000 | 1.4% | 70,000 | 0.0% |
| 140,000 | 139,000 | 0.7% | 139,000 | 0.7% | 140,000 | 0.0% |
| 350,000 | 348,996 | 0.3% | 348,912 | 0.3% | 350,000 | 0.0% |
| 700,000 | 699,000 | 0.1% | 400,193 | 42.8% | 698,643 | 0.2% |

#### 512-byte packets

| Target PPS | rust-dpdk RX | Drop | Kernel RX | Drop | native-dpdk RX | Drop |
|-----------|-------------|------|----------|------|---------------|------|
| 70,000 | 69,000 | 1.4% | 69,000 | 1.4% | 70,000 | 0.0% |
| 140,000 | 139,000 | 0.7% | 139,000 | 0.7% | 140,000 | 0.0% |
| 350,000 | 349,000 | 0.3% | 348,883 | 0.3% | 350,000 | 0.0% |
| 700,000 | 699,000 | 0.1% | 582,543 | 16.8% | 698,348 | 0.2% |

#### 1400-byte packets (near MTU)

| Target PPS | rust-dpdk RX | Drop | Kernel RX | Drop | native-dpdk RX | Drop |
|-----------|-------------|------|----------|------|---------------|------|
| 70,000 | 69,000 | 1.4% | 69,000 | 1.4% | 70,000 | 0.0% |
| 140,000 | 139,000 | 0.7% | 139,000 | 0.7% | 140,000 | 0.0% |
| 350,000 | 349,000 | 0.3% | 348,957 | 0.3% | 350,000 | 0.0% |
| 700,000 | 569,926 | 18.6% | 583,762 | 16.6% | 674,637 | 3.6% |

#### 8500-byte packets (jumbo)

| Target PPS | rust-dpdk RX | Drop | Kernel RX | Drop | native-dpdk RX | Drop |
|-----------|-------------|------|----------|------|---------------|------|
| 70,000 | 69,000 | 1.4% | 33,908 | 51.6% | 70,000 | 0.0% |
| 140,000 | 124,350 | 0.7% | 124,329 | 0.7% | 125,301 | 0.0% |
| 350,000 | 123,085 | 1.7% | 124,013 | 1.0% | 120,300 | 3.9% |

#### tokio-dpdk (async compat layer)

| Target PPS | tokio-dpdk RX | Drop |
|-----------|--------------|------|
| 70,000 | 69,000 | 1.4% |
| 140,000 | 139,000 | 0.7% |
| 350,000 | 307,647 | 12.1% |
| 700,000 | 307,850 | 56.0% |

### NIC Drops Instrumentation Self-Check

| Config | Status | imissed (expected / actual / Δ) | ierrors (expected / actual / Δ) | rx_nombuf (expected / actual / Δ) |
|--------|--------|--------------------------------|----------------------------------|-----------------------------------|
| native-dpdk | no instrumentation | — | — | — |
| rust-dpdk | **OK** | 0 / 0 / 0 | 422,439 / 422,439 / 0 | 0 / 0 / 0 |
| tokio-dpdk | **OK** | 0 / 0 / 0 | 263,721 / 263,721 / 0 | 0 / 0 / 0 |
| plain-rust | no instrumentation | — | — | — |

### Analysis

**No performance regression from IPv6 outer encap.** The feature adds new `build_*_frame_into_v6()` and `try_decap_*_v6()` functions alongside the existing IPv4 encap code. Zero changes to the existing hot path — no new branches, no new Option checks in `send_to_addr()` or `process_frame_zerocopy()`.

**rust-dpdk at 700K PPS, 64B**: 699,000 RX (0.1% drop) — matches Run #18's 699,000 exactly.

**rust-dpdk at 700K PPS, 512B**: 699,000 RX (0.1% drop) — matches Run #18's 699,000 exactly.

**rust-dpdk at 700K PPS, 1400B**: 569,926 RX (18.6% drop) — identical to Run #18's 569,926.

**rust-dpdk vs native-dpdk parity**: At 700K PPS with 64B packets, Rust delivers 699,000 vs native C's 698,643 — Rust is marginally ahead (within measurement noise). At 350K PPS, both deliver ~349K with <0.3% drops.

**tokio-dpdk**: Caps at ~307K PPS at 350K+ target — consistent with Run #18's 307,647, confirming the async compat layer ceiling is unchanged.

**Conclusion**: IPv6 outer encap is performance-neutral. The new code paths are only invoked when the IPv6 outer build/decap functions are explicitly called — they do not affect the existing IPv4 encap or plain UDP paths.

---
2. **Synthetic PPS** — `cargo test -- --nocapture vlan_pps_benchmark` (measures pure CPU overhead of RX processing pipeline, independent of NIC speed; ~5s to run)
3. **HW VLAN Strip** — `cargo test -- --nocapture hw_vlan_strip_benchmark` (measures cost of frame reconstruction vs direct hw_vlan_tci passthrough; regression guard for the RX VLAN offload path)

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