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server.go
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server.go
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package encoding
import (
"context"
"crypto/aes"
"crypto/cipher"
"crypto/md5"
"hash/fnv"
"io"
"sync"
"time"
"golang.org/x/crypto/chacha20poly1305"
"v2ray.com/core/common/buf"
"v2ray.com/core/common/crypto"
"v2ray.com/core/common/net"
"v2ray.com/core/common/protocol"
"v2ray.com/core/common/serial"
"v2ray.com/core/common/signal"
"v2ray.com/core/proxy/vmess"
)
type sessionId struct {
user [16]byte
key [16]byte
nonce [16]byte
}
type SessionHistory struct {
sync.RWMutex
cache map[sessionId]time.Time
token *signal.Semaphore
ctx context.Context
}
func NewSessionHistory(ctx context.Context) *SessionHistory {
h := &SessionHistory{
cache: make(map[sessionId]time.Time, 128),
token: signal.NewSemaphore(1),
ctx: ctx,
}
return h
}
func (h *SessionHistory) add(session sessionId) {
h.Lock()
h.cache[session] = time.Now().Add(time.Minute * 3)
h.Unlock()
select {
case <-h.token.Wait():
go h.run()
default:
}
}
func (h *SessionHistory) has(session sessionId) bool {
h.RLock()
defer h.RUnlock()
if expire, found := h.cache[session]; found {
return expire.After(time.Now())
}
return false
}
func (h *SessionHistory) run() {
defer h.token.Signal()
for {
select {
case <-h.ctx.Done():
return
case <-time.After(time.Second * 30):
}
session2Remove := make([]sessionId, 0, 16)
now := time.Now()
h.Lock()
if len(h.cache) == 0 {
h.Unlock()
return
}
for session, expire := range h.cache {
if expire.Before(now) {
session2Remove = append(session2Remove, session)
}
}
for _, session := range session2Remove {
delete(h.cache, session)
}
h.Unlock()
}
}
type ServerSession struct {
userValidator protocol.UserValidator
sessionHistory *SessionHistory
requestBodyKey []byte
requestBodyIV []byte
responseBodyKey []byte
responseBodyIV []byte
responseHeader byte
responseWriter io.Writer
}
// NewServerSession creates a new ServerSession, using the given UserValidator.
// The ServerSession instance doesn't take ownership of the validator.
func NewServerSession(validator protocol.UserValidator, sessionHistory *SessionHistory) *ServerSession {
return &ServerSession{
userValidator: validator,
sessionHistory: sessionHistory,
}
}
func (v *ServerSession) DecodeRequestHeader(reader io.Reader) (*protocol.RequestHeader, error) {
buffer := make([]byte, 512)
_, err := io.ReadFull(reader, buffer[:protocol.IDBytesLen])
if err != nil {
return nil, newError("failed to read request header").Base(err)
}
user, timestamp, valid := v.userValidator.Get(buffer[:protocol.IDBytesLen])
if !valid {
return nil, newError("invalid user")
}
timestampHash := md5.New()
timestampHash.Write(hashTimestamp(timestamp))
iv := timestampHash.Sum(nil)
account, err := user.GetTypedAccount()
if err != nil {
return nil, newError("failed to get user account").Base(err)
}
vmessAccount := account.(*vmess.InternalAccount)
aesStream := crypto.NewAesDecryptionStream(vmessAccount.ID.CmdKey(), iv)
decryptor := crypto.NewCryptionReader(aesStream, reader)
nBytes, err := io.ReadFull(decryptor, buffer[:41])
if err != nil {
return nil, newError("failed to read request header").Base(err)
}
bufferLen := nBytes
request := &protocol.RequestHeader{
User: user,
Version: buffer[0],
}
if request.Version != Version {
return nil, newError("invalid protocol version ", request.Version)
}
v.requestBodyIV = append([]byte(nil), buffer[1:17]...) // 16 bytes
v.requestBodyKey = append([]byte(nil), buffer[17:33]...) // 16 bytes
var sid sessionId
copy(sid.user[:], vmessAccount.ID.Bytes())
copy(sid.key[:], v.requestBodyKey)
copy(sid.nonce[:], v.requestBodyIV)
if v.sessionHistory.has(sid) {
return nil, newError("duplicated session id, possibly under replay attack")
}
v.sessionHistory.add(sid)
v.responseHeader = buffer[33] // 1 byte
request.Option = protocol.RequestOption(buffer[34]) // 1 byte
padingLen := int(buffer[35] >> 4)
request.Security = protocol.NormSecurity(protocol.Security(buffer[35] & 0x0F))
// 1 bytes reserved
request.Command = protocol.RequestCommand(buffer[37])
request.Port = net.PortFromBytes(buffer[38:40])
switch buffer[40] {
case AddrTypeIPv4:
_, err = io.ReadFull(decryptor, buffer[41:45]) // 4 bytes
bufferLen += 4
if err != nil {
return nil, newError("failed to read IPv4 address").Base(err)
}
request.Address = net.IPAddress(buffer[41:45])
case AddrTypeIPv6:
_, err = io.ReadFull(decryptor, buffer[41:57]) // 16 bytes
bufferLen += 16
if err != nil {
return nil, newError("failed to read IPv6 address").Base(err)
}
request.Address = net.IPAddress(buffer[41:57])
case AddrTypeDomain:
_, err = io.ReadFull(decryptor, buffer[41:42])
if err != nil {
return nil, newError("failed to read domain address").Base(err)
}
domainLength := int(buffer[41])
if domainLength == 0 {
return nil, newError("zero length domain").Base(err)
}
_, err = io.ReadFull(decryptor, buffer[42:42+domainLength])
if err != nil {
return nil, newError("failed to read domain address").Base(err)
}
bufferLen += 1 + domainLength
request.Address = net.DomainAddress(string(buffer[42 : 42+domainLength]))
}
if padingLen > 0 {
_, err = io.ReadFull(decryptor, buffer[bufferLen:bufferLen+padingLen])
if err != nil {
return nil, newError("failed to read padding").Base(err)
}
bufferLen += padingLen
}
_, err = io.ReadFull(decryptor, buffer[bufferLen:bufferLen+4])
if err != nil {
return nil, newError("failed to read checksum").Base(err)
}
fnv1a := fnv.New32a()
fnv1a.Write(buffer[:bufferLen])
actualHash := fnv1a.Sum32()
expectedHash := serial.BytesToUint32(buffer[bufferLen : bufferLen+4])
if actualHash != expectedHash {
return nil, newError("invalid auth")
}
if request.Address == nil {
return nil, newError("invalid remote address")
}
return request, nil
}
func (v *ServerSession) DecodeRequestBody(request *protocol.RequestHeader, reader io.Reader) buf.Reader {
var sizeParser crypto.ChunkSizeDecoder = crypto.PlainChunkSizeParser{}
if request.Option.Has(protocol.RequestOptionChunkMasking) {
sizeParser = NewShakeSizeParser(v.requestBodyIV)
}
if request.Security.Is(protocol.SecurityType_NONE) {
if request.Option.Has(protocol.RequestOptionChunkStream) {
return crypto.NewChunkStreamReader(sizeParser, reader)
}
return buf.NewReader(reader)
}
if request.Security.Is(protocol.SecurityType_LEGACY) {
aesStream := crypto.NewAesDecryptionStream(v.requestBodyKey, v.requestBodyIV)
cryptionReader := crypto.NewCryptionReader(aesStream, reader)
if request.Option.Has(protocol.RequestOptionChunkStream) {
auth := &crypto.AEADAuthenticator{
AEAD: new(FnvAuthenticator),
NonceGenerator: crypto.NoOpBytesGenerator{},
AdditionalDataGenerator: crypto.NoOpBytesGenerator{},
}
return crypto.NewAuthenticationReader(auth, sizeParser, cryptionReader)
}
return buf.NewReader(cryptionReader)
}
if request.Security.Is(protocol.SecurityType_AES128_GCM) {
block, _ := aes.NewCipher(v.requestBodyKey)
aead, _ := cipher.NewGCM(block)
auth := &crypto.AEADAuthenticator{
AEAD: aead,
NonceGenerator: &ChunkNonceGenerator{
Nonce: append([]byte(nil), v.requestBodyIV...),
Size: aead.NonceSize(),
},
AdditionalDataGenerator: crypto.NoOpBytesGenerator{},
}
return crypto.NewAuthenticationReader(auth, sizeParser, reader)
}
if request.Security.Is(protocol.SecurityType_CHACHA20_POLY1305) {
aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(v.requestBodyKey))
auth := &crypto.AEADAuthenticator{
AEAD: aead,
NonceGenerator: &ChunkNonceGenerator{
Nonce: append([]byte(nil), v.requestBodyIV...),
Size: aead.NonceSize(),
},
AdditionalDataGenerator: crypto.NoOpBytesGenerator{},
}
return crypto.NewAuthenticationReader(auth, sizeParser, reader)
}
panic("Unknown security type.")
}
func (v *ServerSession) EncodeResponseHeader(header *protocol.ResponseHeader, writer io.Writer) {
responseBodyKey := md5.Sum(v.requestBodyKey)
responseBodyIV := md5.Sum(v.requestBodyIV)
v.responseBodyKey = responseBodyKey[:]
v.responseBodyIV = responseBodyIV[:]
aesStream := crypto.NewAesEncryptionStream(v.responseBodyKey, v.responseBodyIV)
encryptionWriter := crypto.NewCryptionWriter(aesStream, writer)
v.responseWriter = encryptionWriter
encryptionWriter.Write([]byte{v.responseHeader, byte(header.Option)})
err := MarshalCommand(header.Command, encryptionWriter)
if err != nil {
encryptionWriter.Write([]byte{0x00, 0x00})
}
}
func (v *ServerSession) EncodeResponseBody(request *protocol.RequestHeader, writer io.Writer) buf.Writer {
var sizeParser crypto.ChunkSizeEncoder = crypto.PlainChunkSizeParser{}
if request.Option.Has(protocol.RequestOptionChunkMasking) {
sizeParser = NewShakeSizeParser(v.responseBodyIV)
}
if request.Security.Is(protocol.SecurityType_NONE) {
if request.Option.Has(protocol.RequestOptionChunkStream) {
return crypto.NewChunkStreamWriter(sizeParser, writer)
}
return buf.NewWriter(writer)
}
if request.Security.Is(protocol.SecurityType_LEGACY) {
if request.Option.Has(protocol.RequestOptionChunkStream) {
auth := &crypto.AEADAuthenticator{
AEAD: new(FnvAuthenticator),
NonceGenerator: crypto.NoOpBytesGenerator{},
AdditionalDataGenerator: crypto.NoOpBytesGenerator{},
}
return crypto.NewAuthenticationWriter(auth, sizeParser, v.responseWriter)
}
return buf.NewWriter(v.responseWriter)
}
if request.Security.Is(protocol.SecurityType_AES128_GCM) {
block, _ := aes.NewCipher(v.responseBodyKey)
aead, _ := cipher.NewGCM(block)
auth := &crypto.AEADAuthenticator{
AEAD: aead,
NonceGenerator: &ChunkNonceGenerator{
Nonce: append([]byte(nil), v.responseBodyIV...),
Size: aead.NonceSize(),
},
AdditionalDataGenerator: crypto.NoOpBytesGenerator{},
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer)
}
if request.Security.Is(protocol.SecurityType_CHACHA20_POLY1305) {
aead, _ := chacha20poly1305.New(GenerateChacha20Poly1305Key(v.responseBodyKey))
auth := &crypto.AEADAuthenticator{
AEAD: aead,
NonceGenerator: &ChunkNonceGenerator{
Nonce: append([]byte(nil), v.responseBodyIV...),
Size: aead.NonceSize(),
},
AdditionalDataGenerator: crypto.NoOpBytesGenerator{},
}
return crypto.NewAuthenticationWriter(auth, sizeParser, writer)
}
panic("Unknown security type.")
}