From 05b83508f84191deed0bdddae5f26848259a7b08 Mon Sep 17 00:00:00 2001 From: V2Ray Date: Mon, 28 Sep 2015 17:13:50 +0200 Subject: [PATCH] Implementation of VMess UDP message --- proxy/vmess/protocol/udp.go | 138 +++++++++++++++++++++++++++++++ proxy/vmess/protocol/udp_test.go | 43 ++++++++++ 2 files changed, 181 insertions(+) create mode 100644 proxy/vmess/protocol/udp.go create mode 100644 proxy/vmess/protocol/udp_test.go diff --git a/proxy/vmess/protocol/udp.go b/proxy/vmess/protocol/udp.go new file mode 100644 index 00000000..b05689de --- /dev/null +++ b/proxy/vmess/protocol/udp.go @@ -0,0 +1,138 @@ +package protocol + +import ( + "crypto/aes" + "crypto/cipher" + "encoding/binary" + "hash/fnv" + "time" + + "github.com/v2ray/v2ray-core/common/errors" + "github.com/v2ray/v2ray-core/common/log" + v2net "github.com/v2ray/v2ray-core/common/net" + "github.com/v2ray/v2ray-core/proxy/vmess/protocol/user" +) + +type VMessUDP struct { + user user.ID + version byte + token uint16 + address v2net.Address + data []byte +} + +func ReadVMessUDP(buffer []byte, userset user.UserSet) (*VMessUDP, error) { + userHash := buffer[:user.IDBytesLen] + userId, timeSec, valid := userset.GetUser(userHash) + if !valid { + return nil, errors.NewAuthenticationError(userHash) + } + + buffer = buffer[user.IDBytesLen:] + aesCipher, err := aes.NewCipher(userId.CmdKey()) + if err != nil { + return nil, err + } + aesStream := cipher.NewCFBDecrypter(aesCipher, user.Int64Hash(timeSec)) + aesStream.XORKeyStream(buffer, buffer) + + fnvHash := binary.BigEndian.Uint32(buffer[:4]) + fnv1a := fnv.New32a() + fnv1a.Write(buffer[4:]) + fnvHashActual := fnv1a.Sum32() + + if fnvHash != fnvHashActual { + log.Warning("Unexpected fhv hash %d, should be %d", fnvHashActual, fnvHash) + return nil, errors.NewCorruptedPacketError() + } + + buffer = buffer[4:] + + vmess := &VMessUDP{ + user: *userId, + version: buffer[0], + token: binary.BigEndian.Uint16(buffer[1:3]), + } + + // buffer[3] is reserved + + port := binary.BigEndian.Uint16(buffer[4:6]) + addrType := buffer[6] + var address v2net.Address + switch addrType { + case addrTypeIPv4: + address = v2net.IPAddress(buffer[7:11], port) + buffer = buffer[11:] + case addrTypeIPv6: + address = v2net.IPAddress(buffer[7:23], port) + buffer = buffer[23:] + case addrTypeDomain: + domainLength := buffer[7] + domain := string(buffer[8 : 8+domainLength]) + address = v2net.DomainAddress(domain, port) + buffer = buffer[8+domainLength:] + default: + log.Warning("Unexpected address type %d", addrType) + return nil, errors.NewCorruptedPacketError() + } + + vmess.address = address + vmess.data = buffer + + return vmess, nil +} + +func (vmess *VMessUDP) ToBytes(idHash user.CounterHash, randomRangeInt64 user.RandomInt64InRange, buffer []byte) []byte { + if buffer == nil { + buffer = make([]byte, 0, 2*1024) + } + + counter := randomRangeInt64(time.Now().UTC().Unix(), 30) + hash := idHash.Hash(vmess.user.Bytes[:], counter) + + buffer = append(buffer, hash...) + encryptBegin := 16 + + // Placeholder for fnv1a hash + buffer = append(buffer, byte(0), byte(0), byte(0), byte(0)) + fnvHash := 16 + fnvHashBegin := 20 + + buffer = append(buffer, vmess.version) + buffer = append(buffer, byte(vmess.token>>8), byte(vmess.token)) + buffer = append(buffer, byte(0x00)) + buffer = append(buffer, vmess.address.PortBytes()...) + switch { + case vmess.address.IsIPv4(): + buffer = append(buffer, addrTypeIPv4) + buffer = append(buffer, vmess.address.IP()...) + case vmess.address.IsIPv6(): + buffer = append(buffer, addrTypeIPv6) + buffer = append(buffer, vmess.address.IP()...) + case vmess.address.IsDomain(): + buffer = append(buffer, addrTypeDomain) + buffer = append(buffer, byte(len(vmess.address.Domain()))) + buffer = append(buffer, []byte(vmess.address.Domain())...) + } + + buffer = append(buffer, vmess.data...) + + fnv1a := fnv.New32a() + fnv1a.Write(buffer[fnvHashBegin:]) + fnvHashValue := fnv1a.Sum32() + + buffer[fnvHash] = byte(fnvHashValue >> 24) + buffer[fnvHash+1] = byte(fnvHashValue >> 16) + buffer[fnvHash+2] = byte(fnvHashValue >> 8) + buffer[fnvHash+3] = byte(fnvHashValue) + + aesCipher, err := aes.NewCipher(vmess.user.CmdKey()) + if err != nil { + log.Error("VMess failed to create AES cipher: %v", err) + return nil + } + aesStream := cipher.NewCFBEncrypter(aesCipher, user.Int64Hash(counter)) + aesStream.XORKeyStream(buffer[encryptBegin:], buffer[encryptBegin:]) + + return buffer +} diff --git a/proxy/vmess/protocol/udp_test.go b/proxy/vmess/protocol/udp_test.go new file mode 100644 index 00000000..9244f6bb --- /dev/null +++ b/proxy/vmess/protocol/udp_test.go @@ -0,0 +1,43 @@ +package protocol + +import ( + "testing" + + v2net "github.com/v2ray/v2ray-core/common/net" + "github.com/v2ray/v2ray-core/proxy/vmess/protocol/user" + "github.com/v2ray/v2ray-core/testing/mocks" + "github.com/v2ray/v2ray-core/testing/unit" +) + +func TestVMessUDPReadWrite(t *testing.T) { + assert := unit.Assert(t) + + userId, err := user.NewID("2b2966ac-16aa-4fbf-8d81-c5f172a3da51") + assert.Error(err).IsNil() + + userSet := mocks.MockUserSet{[]user.ID{}, make(map[string]int), make(map[string]int64)} + userSet.AddUser(user.User{userId}) + + message := &VMessUDP{ + user: userId, + version: byte(0x01), + token: 1234, + address: v2net.DomainAddress("v2ray.com", 8372), + data: []byte("An UDP message."), + } + + mockTime := int64(1823730) + buffer := message.ToBytes(user.NewTimeHash(user.HMACHash{}), func(base int64, delta int) int64 { return mockTime }, nil) + + userSet.UserHashes[string(buffer[:16])] = 0 + userSet.Timestamps[string(buffer[:16])] = mockTime + + messageRestored, err := ReadVMessUDP(buffer, &userSet) + assert.Error(err).IsNil() + + assert.String(messageRestored.user.String).Equals(message.user.String) + assert.Byte(messageRestored.version).Equals(message.version) + assert.Uint16(messageRestored.token).Equals(message.token) + assert.String(messageRestored.address.String()).Equals(message.address.String()) + assert.Bytes(messageRestored.data).Equals(message.data) +}