"crypto/subtle"
"encoding/base64"
"encoding/binary"
+ "encoding/hex"
"hash"
- "log"
"sync"
"time"
+ "github.com/Sirupsen/logrus"
+ "github.com/pkg/errors"
"golang.org/x/crypto/blake2b"
)
-const (
- IDSize = 128 / 8
-)
+// IDSize is a size of GoVPN peer's identity
+const IDSize = 128 / 8
+// PeerID is identifier of a single GoVPN peer (client)
type PeerID [IDSize]byte
+// String returns peer's ID in stringified form
func (id PeerID) String() string {
return base64.RawStdEncoding.EncodeToString(id[:])
}
+// MarshalJSON returns a JSON serialized peer's ID
func (id PeerID) MarshalJSON() ([]byte, error) {
return []byte(`"` + id.String() + `"`), nil
}
+// MACAndTimeSync is a single peer MAC and timesync
type MACAndTimeSync struct {
mac hash.Hash
ts int
l sync.Mutex
}
+// MACCache caches all MACAndTimeSync for peers allowed to connect
type MACCache struct {
cache map[PeerID]*MACAndTimeSync
l sync.RWMutex
}
+// Length returns size of MACCache
+func (mc *MACCache) Length() int {
+ return len(mc.cache)
+}
+
+// NewMACCache returns a new MACCache instance
func NewMACCache() *MACCache {
return &MACCache{cache: make(map[PeerID]*MACAndTimeSync)}
}
-// Remove disappeared keys, add missing ones with initialized MACs.
-func (mc *MACCache) Update(peers *map[PeerID]*PeerConf) {
+// Update removes disappeared keys, add missing ones with initialized MACs.
+func (mc *MACCache) Update(peers *map[PeerID]*PeerConf) error {
mc.l.Lock()
+ defer mc.l.Unlock()
+ fields := logrus.Fields{
+ "func": logFuncPrefix + "MACCache.Update",
+ "peers": len(*peers),
+ }
+ logger.WithFields(fields).WithField("size", mc.Length()).Debug("Clean old keys")
for pid := range mc.cache {
if _, exists := (*peers)[pid]; !exists {
- log.Println("Cleaning key:", pid)
+ logger.WithFields(fields).WithField("pid", pid).Debug("Cleaning key")
delete(mc.cache, pid)
}
}
+ logger.WithFields(fields).WithField("size", mc.Length()).Debug("Cleaned, add/update new key")
for pid, pc := range *peers {
if _, exists := mc.cache[pid]; exists {
+ logger.WithFields(fields).WithFields(
+ logrus.Fields{
+ "pid": pid.String(),
+ "old_ts": mc.cache[pid].ts,
+ "new_ts": pc.TimeSync,
+ }).Debug("Rest timesync")
mc.cache[pid].ts = pc.TimeSync
} else {
- log.Println("Adding key", pid)
+ before := time.Now()
mac, err := blake2b.New256(pid[:])
if err != nil {
- panic(err)
+ return errors.Wrap(err, wrapBlake2bNew256)
}
+ logger.WithFields(fields).WithFields(logrus.Fields{
+ "pid": pid.String(),
+ "ts": pc.TimeSync,
+ "elapsed": time.Now().Sub(before).String(),
+ }).Debug("Adding key")
mc.cache[pid] = &MACAndTimeSync{
mac: mac,
ts: pc.TimeSync,
}
}
}
- mc.l.Unlock()
+ logger.WithFields(fields).WithField("size", mc.Length()).Debug("Finish")
+ return nil
}
-// If timeSync > 0, then XOR timestamp with the data.
+// AddTimeSync XORs timestamp with data if timeSync > 0
func AddTimeSync(ts int, data []byte) {
+ fields := logrus.Fields{
+ "func": logFuncPrefix + "AddTimeSync",
+ "ts": ts,
+ "data_size": len(data),
+ "data": hex.EncodeToString(data),
+ }
if ts == 0 {
return
}
for i := 0; i < 8; i++ {
data[i] ^= buf[i]
}
+ logger.WithFields(fields).WithField("after", hex.EncodeToString(data)).Debug("Done")
}
-// Try to find peer's identity (that equals to MAC)
+// Find tries to find peer's identity (that equals to MAC)
// by taking first blocksize sized bytes from data at the beginning
// as plaintext and last bytes as cyphertext.
-func (mc *MACCache) Find(data []byte) *PeerID {
- if len(data) < 8*2 {
- return nil
+func (mc *MACCache) Find(data []byte) (*PeerID, error) {
+ const minimumSize = 8 * 2
+ fields := logrus.Fields{
+ "func": logFuncPrefix + "MACCache.Find",
+ "data": len(data),
+ "size": mc.Length(),
+ }
+ logger.WithFields(fields).Debug("Starting")
+ if len(data) < minimumSize {
+ return nil, errors.Errorf("MAC is too small %d, minimum %d", len(data), minimumSize)
}
buf := make([]byte, 8)
sum := make([]byte, 32)
mc.l.RLock()
+ defer mc.l.RUnlock()
for pid, mt := range mc.cache {
+ loopFields := logrus.Fields{"pid": pid.String()}
+ logger.WithFields(loopFields).Debug("process")
copy(buf, data)
AddTimeSync(mt.ts, buf)
mt.l.Lock()
mt.mac.Reset()
- mt.mac.Write(buf)
+ logger.WithFields(fields).WithField("buf", hex.EncodeToString(buf)).Debug("mt.mac.Write")
+ if _, err := mt.mac.Write(buf); err != nil {
+ mt.l.Unlock()
+ return nil, errors.Wrap(err, "mt.mac.Write")
+ }
+ logger.WithFields(fields).WithField("buf", hex.EncodeToString(buf[:0])).Debug("mt.mac.Sum")
mt.mac.Sum(sum[:0])
mt.l.Unlock()
+
if subtle.ConstantTimeCompare(sum[len(sum)-8:], data[len(data)-8:]) == 1 {
+ logger.WithFields(fields).WithFields(loopFields).Debug("Matching peer")
ppid := PeerID(pid)
- mc.l.RUnlock()
- return &ppid
+ return &ppid, nil
}
+
+ logger.WithFields(fields).WithFields(loopFields).Debug("Not matching peer")
}
- mc.l.RUnlock()
- return nil
+ logger.WithFields(fields).Debug("Can't find matching peer ID")
+ return nil, nil
}