From f3c14cd893136af3bc8ccebd179763b3657d133f Mon Sep 17 00:00:00 2001
From: Mikhail Chusavitin <mchusavitin@mchusmbp.local>
Date: Sat, 4 Apr 2026 15:23:15 +0300
Subject: [PATCH] Harden NIC probing for empty SFP ports

---
 audit/internal/collector/nic_mellanox.go      | 29 +++++++++++++-
 audit/internal/collector/nic_telemetry.go     | 12 +++---
 .../internal/collector/nic_telemetry_test.go  | 39 +++++++++++++++++++
 3 files changed, 73 insertions(+), 7 deletions(-)

diff --git a/audit/internal/collector/nic_mellanox.go b/audit/internal/collector/nic_mellanox.go
index 28f4821..80e4f9c 100644
--- a/audit/internal/collector/nic_mellanox.go
+++ b/audit/internal/collector/nic_mellanox.go
@@ -2,18 +2,21 @@ package collector
 
 import (
 	"bee/audit/internal/schema"
+	"context"
 	"log/slog"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"
+	"time"
 )
 
 const mellanoxVendorID = 0x15b3
+const nicProbeTimeout = 2 * time.Second
 
 var (
 	mstflintQuery = func(bdf string) (string, error) {
-		out, err := exec.Command("mstflint", "-d", bdf, "q").Output()
+		out, err := commandOutputWithTimeout(nicProbeTimeout, "mstflint", "-d", bdf, "q")
 		if err != nil {
 			return "", err
 		}
@@ -21,7 +24,7 @@ var (
 	}
 
 	ethtoolInfoQuery = func(iface string) (string, error) {
-		out, err := exec.Command("ethtool", "-i", iface).Output()
+		out, err := commandOutputWithTimeout(nicProbeTimeout, "ethtool", "-i", iface)
 		if err != nil {
 			return "", err
 		}
@@ -29,6 +32,14 @@ var (
 	}
 
 	netIfacesByBDF = listNetIfacesByBDF
+	readNetCarrierFile = func(iface string) (string, error) {
+		path := filepath.Join("/sys/class/net", iface, "carrier")
+		raw, err := os.ReadFile(path)
+		if err != nil {
+			return "", err
+		}
+		return strings.TrimSpace(string(raw)), nil
+	}
 )
 
 // enrichPCIeWithMellanox enriches Mellanox/NVIDIA Networking devices with
@@ -162,3 +173,17 @@ func listNetIfacesByBDF(bdf string) []string {
 	}
 	return ifaces
 }
+
+func commandOutputWithTimeout(timeout time.Duration, name string, args ...string) ([]byte, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	return exec.CommandContext(ctx, name, args...).Output()
+}
+
+func interfaceHasCarrier(iface string) bool {
+	raw, err := readNetCarrierFile(iface)
+	if err != nil {
+		return false
+	}
+	return strings.TrimSpace(raw) == "1"
+}
diff --git a/audit/internal/collector/nic_telemetry.go b/audit/internal/collector/nic_telemetry.go
index 2ddfabf..ee82199 100644
--- a/audit/internal/collector/nic_telemetry.go
+++ b/audit/internal/collector/nic_telemetry.go
@@ -12,7 +12,7 @@ import (
 
 var (
 	ethtoolModuleQuery = func(iface string) (string, error) {
-		out, err := raidToolQuery("ethtool", "-m", iface)
+		out, err := commandOutputWithTimeout(nicProbeTimeout, "ethtool", "-m", iface)
 		if err != nil {
 			return "", err
 		}
@@ -58,10 +58,12 @@ func enrichPCIeWithNICTelemetry(devs []schema.HardwarePCIeDevice) []schema.Hardw
 			}
 		}
 
-		if out, err := ethtoolModuleQuery(iface); err == nil {
-			if injectSFPDOMTelemetry(&devs[i], out) {
-				enriched++
-				continue
+		if interfaceHasCarrier(iface) {
+			if out, err := ethtoolModuleQuery(iface); err == nil {
+				if injectSFPDOMTelemetry(&devs[i], out) {
+					enriched++
+					continue
+				}
 			}
 		}
 		if len(devs[i].MacAddresses) > 0 || devs[i].Firmware != nil {
diff --git a/audit/internal/collector/nic_telemetry_test.go b/audit/internal/collector/nic_telemetry_test.go
index 6873a49..22f9a2e 100644
--- a/audit/internal/collector/nic_telemetry_test.go
+++ b/audit/internal/collector/nic_telemetry_test.go
@@ -57,6 +57,7 @@ func TestEnrichPCIeWithNICTelemetryAddsSerialFallback(t *testing.T) {
 	origReadMAC := readNetAddressFile
 	origEth := ethtoolInfoQuery
 	origModule := ethtoolModuleQuery
+	origCarrier := readNetCarrierFile
 	t.Cleanup(func() {
 		queryPCILSPCIDetail = origDetail
 		readPCIVPDFile = origVPD
@@ -64,6 +65,7 @@ func TestEnrichPCIeWithNICTelemetryAddsSerialFallback(t *testing.T) {
 		readNetAddressFile = origReadMAC
 		ethtoolInfoQuery = origEth
 		ethtoolModuleQuery = origModule
+		readNetCarrierFile = origCarrier
 	})
 
 	queryPCILSPCIDetail = func(bdf string) (string, error) {
@@ -82,6 +84,7 @@ func TestEnrichPCIeWithNICTelemetryAddsSerialFallback(t *testing.T) {
 		}
 		return "aa:bb:cc:dd:ee:ff", nil
 	}
+	readNetCarrierFile = func(string) (string, error) { return "1", nil }
 	ethtoolInfoQuery = func(string) (string, error) { return "", fmt.Errorf("skip firmware") }
 	ethtoolModuleQuery = func(string) (string, error) { return "", fmt.Errorf("skip optics") }
 
@@ -101,6 +104,42 @@ func TestEnrichPCIeWithNICTelemetryAddsSerialFallback(t *testing.T) {
 	}
 }
 
+func TestEnrichPCIeWithNICTelemetrySkipsModuleQueryWithoutCarrier(t *testing.T) {
+	origIfaces := netIfacesByBDF
+	origReadMAC := readNetAddressFile
+	origEth := ethtoolInfoQuery
+	origModule := ethtoolModuleQuery
+	origCarrier := readNetCarrierFile
+	t.Cleanup(func() {
+		netIfacesByBDF = origIfaces
+		readNetAddressFile = origReadMAC
+		ethtoolInfoQuery = origEth
+		ethtoolModuleQuery = origModule
+		readNetCarrierFile = origCarrier
+	})
+
+	netIfacesByBDF = func(string) []string { return []string{"eth0"} }
+	readNetAddressFile = func(string) (string, error) { return "aa:bb:cc:dd:ee:ff", nil }
+	readNetCarrierFile = func(string) (string, error) { return "0", nil }
+	ethtoolInfoQuery = func(string) (string, error) { return "", fmt.Errorf("skip firmware") }
+	ethtoolModuleQuery = func(string) (string, error) {
+		t.Fatal("ethtool -m should not be called without carrier")
+		return "", nil
+	}
+
+	class := "EthernetController"
+	bdf := "0000:18:00.0"
+	devs := []schema.HardwarePCIeDevice{{
+		DeviceClass: &class,
+		BDF:         &bdf,
+	}}
+
+	out := enrichPCIeWithNICTelemetry(devs)
+	if len(out[0].MacAddresses) != 1 || out[0].MacAddresses[0] != "aa:bb:cc:dd:ee:ff" {
+		t.Fatalf("mac_addresses=%v", out[0].MacAddresses)
+	}
+}
+
 func TestDBMValue(t *testing.T) {
 	tests := []struct {
 		in   string