mirror of
https://github.com/SagerNet/sing-box.git
synced 2024-11-12 20:03:38 +00:00
278 lines
6.7 KiB
Go
278 lines
6.7 KiB
Go
package protocol
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import (
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"bytes"
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"encoding/binary"
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"math"
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"math/rand"
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"net"
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"strconv"
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"strings"
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"github.com/Dreamacro/clash/common/pool"
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"github.com/Dreamacro/clash/transport/ssr/tools"
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)
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type (
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hmacMethod func(key, data []byte) []byte
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hashDigestMethod func([]byte) []byte
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)
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func init() {
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register("auth_aes128_sha1", newAuthAES128SHA1, 9)
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}
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type authAES128Function struct {
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salt string
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hmac hmacMethod
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hashDigest hashDigestMethod
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}
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type authAES128 struct {
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*Base
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*authData
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*authAES128Function
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*userData
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iv []byte
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hasSentHeader bool
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rawTrans bool
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packID uint32
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recvID uint32
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}
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func newAuthAES128SHA1(b *Base) Protocol {
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a := &authAES128{
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Base: b,
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authData: &authData{},
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authAES128Function: &authAES128Function{salt: "auth_aes128_sha1", hmac: tools.HmacSHA1, hashDigest: tools.SHA1Sum},
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userData: &userData{},
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}
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a.initUserData()
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return a
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}
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func (a *authAES128) initUserData() {
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params := strings.Split(a.Param, ":")
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if len(params) > 1 {
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if userID, err := strconv.ParseUint(params[0], 10, 32); err == nil {
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binary.LittleEndian.PutUint32(a.userID[:], uint32(userID))
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a.userKey = a.hashDigest([]byte(params[1]))
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}
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}
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if len(a.userKey) == 0 {
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a.userKey = a.Key
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rand.Read(a.userID[:])
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}
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}
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func (a *authAES128) StreamConn(c net.Conn, iv []byte) net.Conn {
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p := &authAES128{
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Base: a.Base,
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authData: a.next(),
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authAES128Function: a.authAES128Function,
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userData: a.userData,
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packID: 1,
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recvID: 1,
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}
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p.iv = iv
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return &Conn{Conn: c, Protocol: p}
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}
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func (a *authAES128) PacketConn(c net.PacketConn) net.PacketConn {
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p := &authAES128{
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Base: a.Base,
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authAES128Function: a.authAES128Function,
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userData: a.userData,
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}
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return &PacketConn{PacketConn: c, Protocol: p}
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}
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func (a *authAES128) Decode(dst, src *bytes.Buffer) error {
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if a.rawTrans {
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dst.ReadFrom(src)
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return nil
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}
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for src.Len() > 4 {
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macKey := pool.Get(len(a.userKey) + 4)
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defer pool.Put(macKey)
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copy(macKey, a.userKey)
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binary.LittleEndian.PutUint32(macKey[len(a.userKey):], a.recvID)
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if !bytes.Equal(a.hmac(macKey, src.Bytes()[:2])[:2], src.Bytes()[2:4]) {
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src.Reset()
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return errAuthAES128MACError
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}
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length := int(binary.LittleEndian.Uint16(src.Bytes()[:2]))
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if length >= 8192 || length < 7 {
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a.rawTrans = true
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src.Reset()
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return errAuthAES128LengthError
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}
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if length > src.Len() {
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break
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}
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if !bytes.Equal(a.hmac(macKey, src.Bytes()[:length-4])[:4], src.Bytes()[length-4:length]) {
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a.rawTrans = true
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src.Reset()
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return errAuthAES128ChksumError
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}
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a.recvID++
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pos := int(src.Bytes()[4])
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if pos < 255 {
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pos += 4
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} else {
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pos = int(binary.LittleEndian.Uint16(src.Bytes()[5:7])) + 4
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}
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dst.Write(src.Bytes()[pos : length-4])
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src.Next(length)
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}
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return nil
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}
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func (a *authAES128) Encode(buf *bytes.Buffer, b []byte) error {
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fullDataLength := len(b)
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if !a.hasSentHeader {
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dataLength := getDataLength(b)
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a.packAuthData(buf, b[:dataLength])
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b = b[dataLength:]
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a.hasSentHeader = true
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}
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for len(b) > 8100 {
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a.packData(buf, b[:8100], fullDataLength)
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b = b[8100:]
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}
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if len(b) > 0 {
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a.packData(buf, b, fullDataLength)
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}
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return nil
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}
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func (a *authAES128) DecodePacket(b []byte) ([]byte, error) {
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if len(b) < 4 {
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return nil, errAuthAES128LengthError
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}
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if !bytes.Equal(a.hmac(a.Key, b[:len(b)-4])[:4], b[len(b)-4:]) {
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return nil, errAuthAES128ChksumError
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}
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return b[:len(b)-4], nil
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}
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func (a *authAES128) EncodePacket(buf *bytes.Buffer, b []byte) error {
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buf.Write(b)
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buf.Write(a.userID[:])
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buf.Write(a.hmac(a.userKey, buf.Bytes())[:4])
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return nil
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}
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func (a *authAES128) packData(poolBuf *bytes.Buffer, data []byte, fullDataLength int) {
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dataLength := len(data)
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randDataLength := a.getRandDataLengthForPackData(dataLength, fullDataLength)
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/*
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2: uint16 LittleEndian packedDataLength
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2: hmac of packedDataLength
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3: maxRandDataLengthPrefix (min:1)
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4: hmac of packedData except the last 4 bytes
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*/
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packedDataLength := 2 + 2 + 3 + randDataLength + dataLength + 4
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if randDataLength < 128 {
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packedDataLength -= 2
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}
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macKey := pool.Get(len(a.userKey) + 4)
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defer pool.Put(macKey)
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copy(macKey, a.userKey)
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binary.LittleEndian.PutUint32(macKey[len(a.userKey):], a.packID)
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a.packID++
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binary.Write(poolBuf, binary.LittleEndian, uint16(packedDataLength))
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poolBuf.Write(a.hmac(macKey, poolBuf.Bytes()[poolBuf.Len()-2:])[:2])
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a.packRandData(poolBuf, randDataLength)
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poolBuf.Write(data)
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poolBuf.Write(a.hmac(macKey, poolBuf.Bytes()[poolBuf.Len()-packedDataLength+4:])[:4])
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}
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func trapezoidRandom(max int, d float64) int {
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base := rand.Float64()
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if d-0 > 1e-6 {
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a := 1 - d
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base = (math.Sqrt(a*a+4*d*base) - a) / (2 * d)
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}
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return int(base * float64(max))
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}
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func (a *authAES128) getRandDataLengthForPackData(dataLength, fullDataLength int) int {
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if fullDataLength >= 32*1024-a.Overhead {
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return 0
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}
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// 1460: tcp_mss
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revLength := 1460 - dataLength - 9
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if revLength == 0 {
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return 0
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}
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if revLength < 0 {
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if revLength > -1460 {
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return trapezoidRandom(revLength+1460, -0.3)
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}
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return rand.Intn(32)
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}
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if dataLength > 900 {
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return rand.Intn(revLength)
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}
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return trapezoidRandom(revLength, -0.3)
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}
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func (a *authAES128) packAuthData(poolBuf *bytes.Buffer, data []byte) {
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if len(data) == 0 {
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return
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}
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dataLength := len(data)
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randDataLength := a.getRandDataLengthForPackAuthData(dataLength)
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/*
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7: checkHead(1) and hmac of checkHead(6)
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4: userID
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16: encrypted data of authdata(12), uint16 BigEndian packedDataLength(2) and uint16 BigEndian randDataLength(2)
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4: hmac of userID and encrypted data
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4: hmac of packedAuthData except the last 4 bytes
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*/
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packedAuthDataLength := 7 + 4 + 16 + 4 + randDataLength + dataLength + 4
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macKey := pool.Get(len(a.iv) + len(a.Key))
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defer pool.Put(macKey)
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copy(macKey, a.iv)
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copy(macKey[len(a.iv):], a.Key)
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poolBuf.WriteByte(byte(rand.Intn(256)))
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poolBuf.Write(a.hmac(macKey, poolBuf.Bytes())[:6])
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poolBuf.Write(a.userID[:])
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err := a.authData.putEncryptedData(poolBuf, a.userKey, [2]int{packedAuthDataLength, randDataLength}, a.salt)
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if err != nil {
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poolBuf.Reset()
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return
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}
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poolBuf.Write(a.hmac(macKey, poolBuf.Bytes()[7:])[:4])
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tools.AppendRandBytes(poolBuf, randDataLength)
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poolBuf.Write(data)
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poolBuf.Write(a.hmac(a.userKey, poolBuf.Bytes())[:4])
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}
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func (a *authAES128) getRandDataLengthForPackAuthData(size int) int {
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if size > 400 {
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return rand.Intn(512)
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}
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return rand.Intn(1024)
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}
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func (a *authAES128) packRandData(poolBuf *bytes.Buffer, size int) {
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if size < 128 {
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poolBuf.WriteByte(byte(size + 1))
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tools.AppendRandBytes(poolBuf, size)
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return
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}
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poolBuf.WriteByte(255)
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binary.Write(poolBuf, binary.LittleEndian, uint16(size+3))
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tools.AppendRandBytes(poolBuf, size)
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}
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