2 GoVPN -- simple secure free software virtual private network daemon
3 Copyright (C) 2014-2015 Sergey Matveev <stargrave@stargrave.org>
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
33 "github.com/agl/ed25519"
34 "golang.org/x/crypto/xtea"
39 RefreshRate = 60 * time.Second
42 type PeerId [IDSize]byte
44 func (id PeerId) String() string {
45 return hex.EncodeToString(id[:])
48 // Return human readable name of the peer.
49 // It equals either to peers/PEER/name file contents or PEER's hex.
50 func (id PeerId) MarshalJSON() ([]byte, error) {
52 if name, err := ioutil.ReadFile(path.Join(PeersPath, result, "name")); err == nil {
53 result = strings.TrimRight(string(name), "\n")
55 return []byte(`"` + result + `"`), nil
58 type PeerConf struct {
64 // This is passphrase verifier
65 DSAPub *[ed25519.PublicKeySize]byte
66 // This field exists only in dummy configuration on client's side
67 DSAPriv *[ed25519.PrivateKeySize]byte
70 type cipherCache map[PeerId]*xtea.Cipher
75 cipherCacheLock sync.RWMutex
79 // Initialize (pre-cache) available peers info.
80 func PeersInit(path string) {
82 IDsCache = make(map[PeerId]*xtea.Cipher)
86 time.Sleep(RefreshRate)
91 // Initialize dummy cache for client-side usage.
92 func PeersInitDummy(id *PeerId, conf *PeerConf) {
93 IDsCache = make(map[PeerId]*xtea.Cipher)
94 cipher, err := xtea.NewCipher(id[:])
98 IDsCache[*id] = cipher
102 // Refresh IDsCache: remove disappeared keys, add missing ones with
103 // initialized ciphers.
104 func (cc cipherCache) refresh() {
105 dir, err := os.Open(PeersPath)
109 peerIds, err := dir.Readdirnames(0)
113 available := make(map[PeerId]bool)
114 for _, peerId := range peerIds {
115 id := IDDecode(peerId)
119 available[*id] = true
122 cipherCacheLock.Lock()
123 // Cleanup deleted ones from cache
124 for k, _ := range cc {
125 if _, exists := available[k]; !exists {
127 log.Println("Cleaning key: ", k)
131 for peerId, _ := range available {
132 if _, exists := cc[peerId]; !exists {
133 log.Println("Adding key", peerId)
134 cipher, err := xtea.NewCipher(peerId[:])
141 cipherCacheLock.Unlock()
144 // Try to find peer's identity (that equals to an encryption key)
145 // by taking first blocksize sized bytes from data at the beginning
146 // as plaintext and last bytes as cyphertext.
147 func (cc cipherCache) Find(data []byte) *PeerId {
148 if len(data) < xtea.BlockSize*2 {
151 buf := make([]byte, xtea.BlockSize)
152 cipherCacheLock.RLock()
153 for pid, cipher := range cc {
154 cipher.Decrypt(buf, data[len(data)-xtea.BlockSize:])
155 if subtle.ConstantTimeCompare(buf, data[:xtea.BlockSize]) == 1 {
157 cipherCacheLock.RUnlock()
161 cipherCacheLock.RUnlock()
165 func readIntFromFile(path string) (int, error) {
166 data, err := ioutil.ReadFile(path)
170 val, err := strconv.Atoi(strings.TrimRight(string(data), "\n"))
177 // Get peer related configuration.
178 func (id *PeerId) Conf() *PeerConf {
179 if dummyConf != nil {
182 conf := PeerConf{Id: id, Noncediff: 1, NoiseEnable: false, CPR: 0}
183 peerPath := path.Join(PeersPath, id.String())
185 verPath := path.Join(peerPath, "verifier")
186 keyData, err := ioutil.ReadFile(verPath)
188 log.Println("Unable to read verifier:", verPath)
191 if len(keyData) < ed25519.PublicKeySize*2 {
192 log.Println("Verifier must be 64 hex characters long:", verPath)
195 keyDecoded, err := hex.DecodeString(string(keyData[:ed25519.PublicKeySize*2]))
197 log.Println("Unable to decode the key:", err.Error(), verPath)
200 conf.DSAPub = new([ed25519.PublicKeySize]byte)
201 copy(conf.DSAPub[:], keyDecoded)
203 timeout := TimeoutDefault
204 if val, err := readIntFromFile(path.Join(peerPath, "timeout")); err == nil {
207 conf.Timeout = time.Second * time.Duration(timeout)
209 if val, err := readIntFromFile(path.Join(peerPath, "noncediff")); err == nil {
212 if val, err := readIntFromFile(path.Join(peerPath, "noise")); err == nil && val == 1 {
213 conf.NoiseEnable = true
215 if val, err := readIntFromFile(path.Join(peerPath, "cpr")); err == nil {
221 // Decode identification string.
222 // It must be 32 hexadecimal characters long.
223 // If it is not the valid one, then return nil.
224 func IDDecode(raw string) *PeerId {
225 if len(raw) != IDSize*2 {
228 idDecoded, err := hex.DecodeString(raw)
232 idP := new([IDSize]byte)
233 copy(idP[:], idDecoded)