Add -vppcfg flag to set ifAlias from the 'description' fields in vppcfg.yaml

ifmib/ifmib.go

@@ -2,6 +2,7 @@ package ifmib
 
 import (
 	"fmt"
+	"io/ioutil"
 	"sync"
 	"time"
 
@@ -9,6 +10,7 @@ import (
 	"github.com/posteo/go-agentx/pdu"
 	"github.com/posteo/go-agentx/value"
 	"go.fd.io/govpp/api"
+	"gopkg.in/yaml.v3"
 	
 	"govpp-snmp-example/logger"
 	"govpp-snmp-example/vppstats"
@@ -56,22 +58,36 @@ import (
 // ifHCOutUcastPkts    .11 - Counter64
 // ifHCOutMulticastPkts .12 - Counter64
 // ifHCOutBroadcastPkts .13 - Counter64
+// ifAlias             .18 - DisplayString
 
 const ifEntryOID = "1.3.6.1.2.1.2.2.1"
 const ifXTableOID = "1.3.6.1.2.1.31.1.1.1"
 
+// VPP Config YAML structures
+type VPPConfig struct {
+	Interfaces map[string]VPPInterface `yaml:"interfaces"`
+	Loopbacks  map[string]VPPInterface `yaml:"loopbacks"`
+}
+
+type VPPInterface struct {
+	Description    string                    `yaml:"description"`
+	SubInterfaces  map[string]VPPInterface   `yaml:"sub-interfaces"`
+}
+
 type InterfaceMIB struct {
 	mutex           sync.RWMutex
 	handler         *agentx.ListHandler
 	ifEntrySession  *agentx.Session
 	ifXTableSession *agentx.Session
 	stats           map[uint32]*api.InterfaceCounters // indexed by interface index
+	descriptions    map[string]string                 // interface name -> description mapping
 }
 
 func NewInterfaceMIB() *InterfaceMIB {
 	return &InterfaceMIB{
-		handler: &agentx.ListHandler{},
-		stats:   make(map[uint32]*api.InterfaceCounters),
+		handler:      &agentx.ListHandler{},
+		stats:        make(map[uint32]*api.InterfaceCounters),
+		descriptions: make(map[string]string),
 	}
 }
 
@@ -79,6 +95,51 @@ func (m *InterfaceMIB) GetHandler() *agentx.ListHandler {
 	return m.handler
 }
 
+func (m *InterfaceMIB) LoadVPPConfig(configPath string) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	// Read YAML file
+	data, err := ioutil.ReadFile(configPath)
+	if err != nil {
+		return fmt.Errorf("failed to read VPP config file: %v", err)
+	}
+
+	// Parse YAML
+	var config VPPConfig
+	if err := yaml.Unmarshal(data, &config); err != nil {
+		return fmt.Errorf("failed to parse VPP config YAML: %v", err)
+	}
+
+	// Extract interface descriptions
+	for ifName, ifConfig := range config.Interfaces {
+		if ifConfig.Description != "" {
+			m.descriptions[ifName] = ifConfig.Description
+			logger.Debugf("Loaded description for interface %s: %s", ifName, ifConfig.Description)
+		}
+
+		// Process sub-interfaces
+		for subID, subConfig := range ifConfig.SubInterfaces {
+			if subConfig.Description != "" {
+				subIfName := fmt.Sprintf("%s.%s", ifName, subID)
+				m.descriptions[subIfName] = subConfig.Description
+				logger.Debugf("Loaded description for sub-interface %s: %s", subIfName, subConfig.Description)
+			}
+		}
+	}
+
+	// Extract loopback descriptions
+	for ifName, ifConfig := range config.Loopbacks {
+		if ifConfig.Description != "" {
+			m.descriptions[ifName] = ifConfig.Description
+			logger.Debugf("Loaded description for loopback %s: %s", ifName, ifConfig.Description)
+		}
+	}
+
+	logger.Printf("Loaded %d interface descriptions from VPP config", len(m.descriptions))
+	return nil
+}
+
 func (m *InterfaceMIB) UpdateStats(interfaceStats *api.InterfaceStats) {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
@@ -298,6 +359,16 @@ func (m *InterfaceMIB) addIfXTable(iface *api.InterfaceCounters, idx int) {
 	item = m.handler.Add(fmt.Sprintf("%s.13.%d", ifXTableOID, idx))
 	item.Type = pdu.VariableTypeCounter64
 	item.Value = iface.TxBroadcast.Packets
+
+	// ifAlias (.18) - Interface description/alias
+	item = m.handler.Add(fmt.Sprintf("%s.18.%d", ifXTableOID, idx))
+	item.Type = pdu.VariableTypeOctetString
+	// Use description from VPP config if available, otherwise use interface name
+	if desc, exists := m.descriptions[iface.InterfaceName]; exists {
+		item.Value = desc
+	} else {
+		item.Value = iface.InterfaceName
+	}
 }
 
 func (m *InterfaceMIB) RegisterWithClient(client *agentx.Client) error {