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forgejo/modules/asn1-ber/ber.go

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package ber
import (
"bytes"
"fmt"
"io"
"reflect"
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"errors"
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)
type Packet struct {
ClassType uint8
TagType uint8
Tag uint8
Value interface{}
ByteValue []byte
Data *bytes.Buffer
Children []*Packet
Description string
}
const (
TagEOC = 0x00
TagBoolean = 0x01
TagInteger = 0x02
TagBitString = 0x03
TagOctetString = 0x04
TagNULL = 0x05
TagObjectIdentifier = 0x06
TagObjectDescriptor = 0x07
TagExternal = 0x08
TagRealFloat = 0x09
TagEnumerated = 0x0a
TagEmbeddedPDV = 0x0b
TagUTF8String = 0x0c
TagRelativeOID = 0x0d
TagSequence = 0x10
TagSet = 0x11
TagNumericString = 0x12
TagPrintableString = 0x13
TagT61String = 0x14
TagVideotexString = 0x15
TagIA5String = 0x16
TagUTCTime = 0x17
TagGeneralizedTime = 0x18
TagGraphicString = 0x19
TagVisibleString = 0x1a
TagGeneralString = 0x1b
TagUniversalString = 0x1c
TagCharacterString = 0x1d
TagBMPString = 0x1e
TagBitmask = 0x1f // xxx11111b
)
var TagMap = map[uint8]string{
TagEOC: "EOC (End-of-Content)",
TagBoolean: "Boolean",
TagInteger: "Integer",
TagBitString: "Bit String",
TagOctetString: "Octet String",
TagNULL: "NULL",
TagObjectIdentifier: "Object Identifier",
TagObjectDescriptor: "Object Descriptor",
TagExternal: "External",
TagRealFloat: "Real (float)",
TagEnumerated: "Enumerated",
TagEmbeddedPDV: "Embedded PDV",
TagUTF8String: "UTF8 String",
TagRelativeOID: "Relative-OID",
TagSequence: "Sequence and Sequence of",
TagSet: "Set and Set OF",
TagNumericString: "Numeric String",
TagPrintableString: "Printable String",
TagT61String: "T61 String",
TagVideotexString: "Videotex String",
TagIA5String: "IA5 String",
TagUTCTime: "UTC Time",
TagGeneralizedTime: "Generalized Time",
TagGraphicString: "Graphic String",
TagVisibleString: "Visible String",
TagGeneralString: "General String",
TagUniversalString: "Universal String",
TagCharacterString: "Character String",
TagBMPString: "BMP String",
}
const (
ClassUniversal = 0 // 00xxxxxxb
ClassApplication = 64 // 01xxxxxxb
ClassContext = 128 // 10xxxxxxb
ClassPrivate = 192 // 11xxxxxxb
ClassBitmask = 192 // 11xxxxxxb
)
var ClassMap = map[uint8]string{
ClassUniversal: "Universal",
ClassApplication: "Application",
ClassContext: "Context",
ClassPrivate: "Private",
}
const (
TypePrimitive = 0 // xx0xxxxxb
TypeConstructed = 32 // xx1xxxxxb
TypeBitmask = 32 // xx1xxxxxb
)
var TypeMap = map[uint8]string{
TypePrimitive: "Primative",
TypeConstructed: "Constructed",
}
var Debug bool = false
func PrintBytes(buf []byte, indent string) {
data_lines := make([]string, (len(buf)/30)+1)
num_lines := make([]string, (len(buf)/30)+1)
for i, b := range buf {
data_lines[i/30] += fmt.Sprintf("%02x ", b)
num_lines[i/30] += fmt.Sprintf("%02d ", (i+1)%100)
}
for i := 0; i < len(data_lines); i++ {
fmt.Print(indent + data_lines[i] + "\n")
fmt.Print(indent + num_lines[i] + "\n\n")
}
}
func PrintPacket(p *Packet) {
printPacket(p, 0, false)
}
func printPacket(p *Packet, indent int, printBytes bool) {
indent_str := ""
for len(indent_str) != indent {
indent_str += " "
}
class_str := ClassMap[p.ClassType]
tagtype_str := TypeMap[p.TagType]
tag_str := fmt.Sprintf("0x%02X", p.Tag)
if p.ClassType == ClassUniversal {
tag_str = TagMap[p.Tag]
}
value := fmt.Sprint(p.Value)
description := ""
if p.Description != "" {
description = p.Description + ": "
}
fmt.Printf("%s%s(%s, %s, %s) Len=%d %q\n", indent_str, description, class_str, tagtype_str, tag_str, p.Data.Len(), value)
if printBytes {
PrintBytes(p.Bytes(), indent_str)
}
for _, child := range p.Children {
printPacket(child, indent+1, printBytes)
}
}
func resizeBuffer(in []byte, new_size uint64) (out []byte) {
out = make([]byte, new_size)
copy(out, in)
return
}
func readBytes(reader io.Reader, buf []byte) error {
idx := 0
buflen := len(buf)
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if reader == nil {
return errors.New("reader was nil, aborting")
}
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for idx < buflen {
n, err := reader.Read(buf[idx:])
if err != nil {
return err
}
idx += n
}
return nil
}
func ReadPacket(reader io.Reader) (*Packet, error) {
buf := make([]byte, 2)
err := readBytes(reader, buf)
if err != nil {
return nil, err
}
idx := uint64(2)
datalen := uint64(buf[1])
if Debug {
fmt.Printf("Read: datalen = %d len(buf) = %d ", datalen, len(buf))
for _, b := range buf {
fmt.Printf("%02X ", b)
}
fmt.Printf("\n")
}
if datalen&128 != 0 {
a := datalen - 128
idx += a
buf = resizeBuffer(buf, 2+a)
err := readBytes(reader, buf[2:])
if err != nil {
return nil, err
}
datalen = DecodeInteger(buf[2 : 2+a])
if Debug {
fmt.Printf("Read: a = %d idx = %d datalen = %d len(buf) = %d", a, idx, datalen, len(buf))
for _, b := range buf {
fmt.Printf("%02X ", b)
}
fmt.Printf("\n")
}
}
buf = resizeBuffer(buf, idx+datalen)
err = readBytes(reader, buf[idx:])
if err != nil {
return nil, err
}
if Debug {
fmt.Printf("Read: len( buf ) = %d idx=%d datalen=%d idx+datalen=%d\n", len(buf), idx, datalen, idx+datalen)
for _, b := range buf {
fmt.Printf("%02X ", b)
}
}
p := DecodePacket(buf)
return p, nil
}
func DecodeString(data []byte) (ret string) {
// for _, c := range data {
// ret += fmt.Sprintf("%c", c)
// }
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return string(data)
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}
func DecodeInteger(data []byte) (ret uint64) {
for _, i := range data {
ret = ret * 256
ret = ret + uint64(i)
}
return
}
func EncodeInteger(val uint64) []byte {
var out bytes.Buffer
found := false
shift := uint(56)
mask := uint64(0xFF00000000000000)
for mask > 0 {
if !found && (val&mask != 0) {
found = true
}
if found || (shift == 0) {
out.Write([]byte{byte((val & mask) >> shift)})
}
shift -= 8
mask = mask >> 8
}
return out.Bytes()
}
func DecodePacket(data []byte) *Packet {
p, _ := decodePacket(data)
return p
}
func decodePacket(data []byte) (*Packet, []byte) {
if Debug {
fmt.Printf("decodePacket: enter %d\n", len(data))
}
p := new(Packet)
p.ClassType = data[0] & ClassBitmask
p.TagType = data[0] & TypeBitmask
p.Tag = data[0] & TagBitmask
datalen := DecodeInteger(data[1:2])
datapos := uint64(2)
if datalen&128 != 0 {
datalen -= 128
datapos += datalen
datalen = DecodeInteger(data[2 : 2+datalen])
}
p.Data = new(bytes.Buffer)
p.Children = make([]*Packet, 0, 2)
p.Value = nil
value_data := data[datapos : datapos+datalen]
if p.TagType == TypeConstructed {
for len(value_data) != 0 {
var child *Packet
child, value_data = decodePacket(value_data)
p.AppendChild(child)
}
} else if p.ClassType == ClassUniversal {
p.Data.Write(data[datapos : datapos+datalen])
p.ByteValue = value_data
switch p.Tag {
case TagEOC:
case TagBoolean:
val := DecodeInteger(value_data)
p.Value = val != 0
case TagInteger:
p.Value = DecodeInteger(value_data)
case TagBitString:
case TagOctetString:
p.Value = DecodeString(value_data)
case TagNULL:
case TagObjectIdentifier:
case TagObjectDescriptor:
case TagExternal:
case TagRealFloat:
case TagEnumerated:
p.Value = DecodeInteger(value_data)
case TagEmbeddedPDV:
case TagUTF8String:
case TagRelativeOID:
case TagSequence:
case TagSet:
case TagNumericString:
case TagPrintableString:
p.Value = DecodeString(value_data)
case TagT61String:
case TagVideotexString:
case TagIA5String:
case TagUTCTime:
case TagGeneralizedTime:
case TagGraphicString:
case TagVisibleString:
case TagGeneralString:
case TagUniversalString:
case TagCharacterString:
case TagBMPString:
}
} else {
p.Data.Write(data[datapos : datapos+datalen])
}
return p, data[datapos+datalen:]
}
func (p *Packet) DataLength() uint64 {
return uint64(p.Data.Len())
}
func (p *Packet) Bytes() []byte {
var out bytes.Buffer
out.Write([]byte{p.ClassType | p.TagType | p.Tag})
packet_length := EncodeInteger(p.DataLength())
if p.DataLength() > 127 || len(packet_length) > 1 {
out.Write([]byte{byte(len(packet_length) | 128)})
out.Write(packet_length)
} else {
out.Write(packet_length)
}
out.Write(p.Data.Bytes())
return out.Bytes()
}
func (p *Packet) AppendChild(child *Packet) {
p.Data.Write(child.Bytes())
if len(p.Children) == cap(p.Children) {
newChildren := make([]*Packet, cap(p.Children)*2)
copy(newChildren, p.Children)
p.Children = newChildren[0:len(p.Children)]
}
p.Children = p.Children[0 : len(p.Children)+1]
p.Children[len(p.Children)-1] = child
}
func Encode(ClassType, TagType, Tag uint8, Value interface{}, Description string) *Packet {
p := new(Packet)
p.ClassType = ClassType
p.TagType = TagType
p.Tag = Tag
p.Data = new(bytes.Buffer)
p.Children = make([]*Packet, 0, 2)
p.Value = Value
p.Description = Description
if Value != nil {
v := reflect.ValueOf(Value)
if ClassType == ClassUniversal {
switch Tag {
case TagOctetString:
sv, ok := v.Interface().(string)
if ok {
p.Data.Write([]byte(sv))
}
}
}
}
return p
}
func NewSequence(Description string) *Packet {
return Encode(ClassUniversal, TypePrimitive, TagSequence, nil, Description)
}
func NewBoolean(ClassType, TagType, Tag uint8, Value bool, Description string) *Packet {
intValue := 0
if Value {
intValue = 1
}
p := Encode(ClassType, TagType, Tag, nil, Description)
p.Value = Value
p.Data.Write(EncodeInteger(uint64(intValue)))
return p
}
func NewInteger(ClassType, TagType, Tag uint8, Value uint64, Description string) *Packet {
p := Encode(ClassType, TagType, Tag, nil, Description)
p.Value = Value
p.Data.Write(EncodeInteger(Value))
return p
}
func NewString(ClassType, TagType, Tag uint8, Value, Description string) *Packet {
p := Encode(ClassType, TagType, Tag, nil, Description)
p.Value = Value
p.Data.Write([]byte(Value))
return p
}