fix: IPv4 CIDRPool gatewayIndex does not match leaf gateway address

[andrewwhitecdw]

This PR addresses the following issue in pkg/networkoperatorplugin/spectrumx/addressing.go: IPv4 CIDRPool gatewayIndex does not match leaf gateway address.

Changes

• pkg/networkoperatorplugin/spectrumx/addressing.go: IPv4 CIDRPool gatewayIndex does not match leaf gateway address.

Details

--- a/pkg/networkoperatorplugin/spectrumx/addressing.go
+++ b/pkg/networkoperatorplugin/spectrumx/addressing.go
@@ -1,5 +1,5 @@
-	return cidrPoolSettings{
-		gatewayIndex:         0,
-		perNodeNetworkPrefix: 31,
-		perNodeExclusions:    []PerNodeExclusion{{StartIndex: 1, EndIndex: 1}},
-	}
+	return cidrPoolSettings{
+		gatewayIndex:         1,
+		perNodeNetworkPrefix: 31,
+		perNodeExclusions:    []PerNodeExclusion{{StartIndex: 1, EndIndex: 1}},
+	}

Tests

• pkg/networkoperatorplugin/spectrumx/addressing_test.go

--- /dev/null
+++ pkg/networkoperatorplugin/spectrumx/addressing_test.go
@@ -0,0 +1,32 @@
+package spectrumx
+
+import (
+	"testing"
+
+	"github.com/nvidia/k8s-launch-kit/pkg/config"
+)
+
+func TestIPv4PoolSettingsGatewayIndexMatchesLeafOffset(t *testing.T) {
+	spcx := &config.ProfileSpectrumX{}
+	settings := poolSettings(spcx)
+	if settings.perNodeNetworkPrefix != 31 {
+		t.Fatalf("IPv4 perNodeNetworkPrefix = %d, want 31", settings.perNodeNetworkPrefix)
+	}
+	if got, want := settings.gatewayIndex, 1; got != want {
+		t.Errorf("IPv4 gatewayIndex = %d, want %d (leaf/gateway is at offset 1 of each /31 block)", got, want)
+	}
+}
+
+func TestIPv6PoolSettingsGatewayIndexUnchanged(t *testing.T) {
+	spcx := &config.ProfileSpectrumX{IPVersion: config.SpectrumXIPVersionIPv6}
+	settings := poolSettings(spcx)
+	if got, want := settings.gatewayIndex, 2; got != want {
+		t.Errorf("IPv6 gatewayIndex = %d, want %d", got, want)
+	}
+}

Contributor guidelines

Per this repo's CONTRIBUTING.md:

• All commits are signed off (Signed-off-by trailer, DCO).

---

Update (post-Greptile review): The existing IPv4 BuildCIDRPools test expectations have been updated to GatewayIndex: 1 to match the implementation change. The Spectrum-X addressing test suite now passes (go test ./pkg/networkoperatorplugin/spectrumx/...). Commit: 7b116ba14dbdeee1a457db743c2c4ce66e473b6b.

[greptile-apps]

Greptile Summary

The PR corrects the Spectrum-X IPv4 CIDRPool gateway offset so it points to the leaf address and updates the affected expectations.

• Changes the IPv4 gatewayIndex from 0 to 1, matching the leaf offset and per-node exclusion.
• Updates all three existing IPv4 gateway-index assertions from 0 to 1.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
pkg/networkoperatorplugin/spectrumx/addressing.go	Aligns the IPv4 CIDRPool gateway index with the leaf address and the existing exclusion at offset 1.
pkg/networkoperatorplugin/spectrumx/addressing_test.go	Updates the three stale IPv4 gateway-index expectations, fully addressing the previous review finding.

_{Reviews (2): Last reviewed commit: "fix: IPv4 CIDRPool gatewayIndex does not..." | Re-trigger Greptile}

[greptile-apps]

IPv4 test expectations remain stale

When the Spectrum-X package tests run, BuildCIDRPools propagates the new gateway index of 1 while three existing IPv4 tests still require 0, causing the test suite to fail. Update those expectations alongside this behavior change.

Knowledge Base Used: Spectrum-X addressing and topology

[andrewwhitecdw]

@greptile-apps Thanks for the review. I updated the stale IPv4 BuildCIDRPools test expectations to GatewayIndex: 1 so they agree with the implementation. go test ./pkg/networkoperatorplugin/spectrumx/... now passes.

[greptile-apps]

The updates look correct. All three GatewayIndex: 0 → GatewayIndex: 1 occurrences in the existing BuildCIDRPools tests are now consistent with the fix, and the new unit tests in addressing_test.go directly assert both the IPv4 (gatewayIndex == 1) and IPv6 (gatewayIndex == 2) cases. The PR is in good shape — LGTM.