feat: support snmp enum

inputs/snmp/table.go

@@ -338,7 +338,7 @@ func (t Table) Build(gs snmpConnection, walk bool, tr Translator) (*RTable, erro
 				pkt.Variables[0].Type != gosnmp.NoSuchObject &&
 				pkt.Variables[0].Type != gosnmp.NoSuchInstance {
 				ent := pkt.Variables[0]
-				fv, err := fieldConvert(f.Conversion, ent.Value)
+				fv, err := fieldConvert(tr, f.Conversion, ent)
 				if err != nil {
 					return nil, fmt.Errorf("converting %q (OID %s) for field %s: %w", ent.Value, ent.Name, f.Name, err)
 				}
@@ -386,7 +386,7 @@ func (t Table) Build(gs snmpConnection, walk bool, tr Translator) (*RTable, erro
 					}
 				}
 
-				fv, err := fieldConvert(f.Conversion, ent.Value)
+				fv, err := fieldConvert(tr, f.Conversion, ent)
 				if err != nil {
 					return &walkError{
 						msg: fmt.Sprintf("converting %q (OID %s) for field %s", ent.Value, ent.Name, f.Name),
@@ -547,16 +547,17 @@ func fieldNonStandardConvertInt64(v string) int64 {
 }
 
 // fieldConvert converts from any type according to the conv specification
-func fieldConvert(conv string, v interface{}) (interface{}, error) {
+func fieldConvert(tr Translator, conv string, ent gosnmp.SnmpPDU) (v interface{}, err error) {
 	if conv == "" {
-		if bs, ok := v.([]byte); ok {
+		if bs, ok := ent.Value.([]byte); ok {
 			return string(bs), nil
 		}
-		return v, nil
+		return ent.Value, nil
 	}
 
 	var d int
 	if _, err := fmt.Sscanf(conv, "float(%d)", &d); err == nil || conv == "float" {
+		v = ent.Value
 		switch vt := v.(type) {
 		case float32:
 			v = float64(vt) / math.Pow10(d)
@@ -593,6 +594,7 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
 	}
 
 	if conv == "int" {
+		v = ent.Value
 		switch vt := v.(type) {
 		case float32:
 			v = int64(vt)
@@ -627,7 +629,7 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
 	}
 
 	if conv == "hwaddr" {
-		switch vt := v.(type) {
+		switch vt := ent.Value.(type) {
 		case string:
 			v = net.HardwareAddr(vt).String()
 		case []byte:
@@ -643,9 +645,9 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
 		endian := split[1]
 		bit := split[2]
 
-		bv, ok := v.([]byte)
+		bv, ok := ent.Value.([]byte)
 		if !ok {
-			return v, nil
+			return ent.Value, nil
 		}
 
 		switch endian {
@@ -681,7 +683,7 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
 	if conv == "ipaddr" {
 		var ipbs []byte
 
-		switch vt := v.(type) {
+		switch vt := ent.Value.(type) {
 		case string:
 			ipbs = []byte(vt)
 		case []byte:
@@ -702,7 +704,7 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
 
 	// 55 57 57 51 46 56 32 77 66   may be the ascii arr for string ->  7993.8 MB
 	if conv == "asciitobytes" {
-
+		v = ent.Value
 		input, ok := v.([]uint8)
 		if !ok {
 			return nil, fmt.Errorf("invalid type of %v (not rune arr)", v)
@@ -759,6 +761,13 @@ func fieldConvert(conv string, v interface{}) (interface{}, error) {
 
 		return result, nil
 	}
+	if conv == "enum" {
+		return tr.SnmpFormatEnum(ent.Name, ent.Value, false)
+	}
+
+	if conv == "enum(1)" {
+		return tr.SnmpFormatEnum(ent.Name, ent.Value, true)
+	}
 
 	return nil, fmt.Errorf("invalid conversion type '%s'", conv)
 }