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/>.
34 "github.com/agl/ed25519"
35 "golang.org/x/crypto/xtea"
40 RefreshRate = 60 * time.Second
43 type PeerId [IDSize]byte
45 func (id PeerId) String() string {
46 return hex.EncodeToString(id[:])
49 // Return human readable name of the peer.
50 // It equals either to peers/PEER/name file contents or PEER's hex.
51 func (id PeerId) MarshalJSON() ([]byte, error) {
53 if name, err := ioutil.ReadFile(path.Join(PeersPath, result, "name")); err == nil {
54 result = strings.TrimRight(string(name), "\n")
56 return []byte(`"` + result + `"`), nil
59 type PeerConf struct {
65 // This is passphrase verifier
66 DSAPub *[ed25519.PublicKeySize]byte
67 // This field exists only in dummy configuration on client's side
68 DSAPriv *[ed25519.PrivateKeySize]byte
71 type cipherCache map[PeerId]*xtea.Cipher
76 cipherCacheLock sync.RWMutex
80 // Initialize (pre-cache) available peers info.
81 func PeersInit(path string) {
83 IDsCache = make(map[PeerId]*xtea.Cipher)
87 time.Sleep(RefreshRate)
92 // Initialize dummy cache for client-side usage.
93 func PeersInitDummy(id *PeerId, conf *PeerConf) {
94 IDsCache = make(map[PeerId]*xtea.Cipher)
95 cipher, err := xtea.NewCipher(id[:])
99 IDsCache[*id] = cipher
103 // Refresh IDsCache: remove disappeared keys, add missing ones with
104 // initialized ciphers.
105 func (cc cipherCache) refresh() {
106 dir, err := os.Open(PeersPath)
110 peerIds, err := dir.Readdirnames(0)
114 available := make(map[PeerId]bool)
115 for _, peerId := range peerIds {
116 id, err := IDDecode(peerId)
120 available[*id] = true
123 cipherCacheLock.Lock()
124 // Cleanup deleted ones from cache
125 for k, _ := range cc {
126 if _, exists := available[k]; !exists {
128 log.Println("Cleaning key: ", k)
132 for peerId, _ := range available {
133 if _, exists := cc[peerId]; !exists {
134 log.Println("Adding key", peerId)
135 cipher, err := xtea.NewCipher(peerId[:])
142 cipherCacheLock.Unlock()
145 // Try to find peer's identity (that equals to an encryption key)
146 // by taking first blocksize sized bytes from data at the beginning
147 // as plaintext and last bytes as cyphertext.
148 func (cc cipherCache) Find(data []byte) *PeerId {
149 if len(data) < xtea.BlockSize*2 {
152 buf := make([]byte, xtea.BlockSize)
153 cipherCacheLock.RLock()
154 for pid, cipher := range cc {
155 cipher.Decrypt(buf, data[len(data)-xtea.BlockSize:])
156 if subtle.ConstantTimeCompare(buf, data[:xtea.BlockSize]) == 1 {
158 cipherCacheLock.RUnlock()
162 cipherCacheLock.RUnlock()
166 func readIntFromFile(path string) (int, error) {
167 data, err := ioutil.ReadFile(path)
171 val, err := strconv.Atoi(strings.TrimRight(string(data), "\n"))
178 // Get peer related configuration.
179 func (id *PeerId) Conf() *PeerConf {
180 if dummyConf != nil {
183 conf := PeerConf{Id: id, Noncediff: 1, NoiseEnable: false, CPR: 0}
184 peerPath := path.Join(PeersPath, id.String())
186 verPath := path.Join(peerPath, "verifier")
187 keyData, err := ioutil.ReadFile(verPath)
189 log.Println("Unable to read verifier:", verPath)
192 if len(keyData) < ed25519.PublicKeySize*2 {
193 log.Println("Verifier must be 64 hex characters long:", verPath)
196 keyDecoded, err := hex.DecodeString(string(keyData[:ed25519.PublicKeySize*2]))
198 log.Println("Unable to decode the key:", err.Error(), verPath)
201 conf.DSAPub = new([ed25519.PublicKeySize]byte)
202 copy(conf.DSAPub[:], keyDecoded)
204 timeout := TimeoutDefault
205 if val, err := readIntFromFile(path.Join(peerPath, "timeout")); err == nil {
208 conf.Timeout = time.Second * time.Duration(timeout)
210 if val, err := readIntFromFile(path.Join(peerPath, "noncediff")); err == nil {
213 if val, err := readIntFromFile(path.Join(peerPath, "noise")); err == nil && val == 1 {
214 conf.NoiseEnable = true
216 if val, err := readIntFromFile(path.Join(peerPath, "cpr")); err == nil {
222 // Decode identification string.
223 // It must be 32 hexadecimal characters long.
224 func IDDecode(raw string) (*PeerId, error) {
225 if len(raw) != IDSize*2 {
226 return nil, errors.New("ID must be 32 characters long")
228 idDecoded, err := hex.DecodeString(raw)
230 return nil, errors.New("ID must contain hexadecimal characters only")
232 idP := new([IDSize]byte)
233 copy(idP[:], idDecoded)