package govpn
import (
- "crypto/subtle"
"encoding/binary"
+ "io"
"log"
"net"
"time"
const (
NonceSize = 8
- KeySize = 32
// S20BS is Salsa20's internal blocksize in bytes
- S20BS = 64
- HeartbeatSize = 12
+ S20BS = 64
// Maximal amount of bytes transfered with single key (4 GiB)
MaxBytesPerKey int64 = 1 << 32
+ // Size of packet's size mark in bytes
+ PktSizeSize = 2
+ // Heartbeat rate, relative to Timeout
+ TimeoutHeartbeat = 4
)
type UDPPkt struct {
}
type Peer struct {
- Addr *net.UDPAddr
- Id PeerId
- Key *[KeySize]byte `json:"-"`
- NonceOur uint64 `json:"-"`
- NonceRecv uint64 `json:"-"`
- NonceCipher *xtea.Cipher `json:"-"`
+ Addr *net.UDPAddr
+ Id *PeerId
+
+ // Traffic behaviour
+ NoiseEnable bool
+ CPR int
+ CPRCycle time.Duration `json:"-"`
+
+ // Cryptography related
+ Key *[SSize]byte `json:"-"`
+ Noncediff int
+ NonceOur uint64 `json:"-"`
+ NonceRecv uint64 `json:"-"`
+ NonceCipher *xtea.Cipher `json:"-"`
+
+ // Timers
+ Timeout time.Duration `json:"-"`
+ Established time.Time
LastPing time.Time
LastSent time.Time
- buf []byte
- tag *[poly1305.TagSize]byte
- keyAuth *[KeySize]byte
- nonceRecv uint64
- frame []byte
- nonce []byte
- BytesIn int64
- BytesOut int64
- FramesIn int
- FramesOut int
- FramesUnauth int
- FramesDup int
- HeartbeatRecv int
- HeartbeatSent int
+ willSentCycle time.Time
+
+ // This variables are initialized only once to relief GC
+ buf []byte
+ tag *[poly1305.TagSize]byte
+ keyAuth *[32]byte
+ nonceRecv uint64
+ frame []byte
+ nonce []byte
+ pktSize uint64
+
+ // Statistics
+ BytesIn int64
+ BytesOut int64
+ BytesPayloadIn int64
+ BytesPayloadOut int64
+ FramesIn int
+ FramesOut int
+ FramesUnauth int
+ FramesDup int
+ HeartbeatRecv int
+ HeartbeatSent int
}
func (p *Peer) String() string {
return p.Id.String() + ":" + p.Addr.String()
}
-// Zero peer's memory state
+// Zero peer's memory state.
func (p *Peer) Zero() {
sliceZero(p.Key[:])
sliceZero(p.tag[:])
}
var (
- HeartbeatMark = []byte("\x00\x00\x00HEARTBEAT")
- Emptiness = make([]byte, KeySize)
- taps = make(map[string]*TAP)
- heartbeatPeriod *time.Duration
+ Emptiness = make([]byte, 1<<14)
+ taps = make(map[string]*TAP)
)
-func heartbeatPeriodGet() time.Duration {
- if heartbeatPeriod == nil {
- period := time.Second * time.Duration(Timeout/4)
- heartbeatPeriod = &period
- }
- return *heartbeatPeriod
-}
-
// Create TAP listening goroutine.
// This function takes required TAP interface name, opens it and allocates
// a buffer where all frame data will be written, channel where information
// about number of read bytes is sent to, synchronization channel (external
// processes tell that read buffer can be used again) and possible channel
// opening error.
-func TAPListen(ifaceName string) (*TAP, chan []byte, chan struct{}, chan struct{}, error) {
+func TAPListen(ifaceName string, timeout time.Duration, cpr int) (*TAP, chan []byte, chan struct{}, chan struct{}, error) {
var tap *TAP
var err error
tap, exists := taps[ifaceName]
sinkSkip := make(chan struct{})
go func() {
- heartbeat := time.Tick(heartbeatPeriodGet())
+ cprCycle := cprCycleCalculate(cpr)
+ if cprCycle != time.Duration(0) {
+ timeout = cprCycle
+ } else {
+ timeout = timeout / TimeoutHeartbeat
+ }
+ heartbeat := time.Tick(timeout)
var pkt []byte
ListenCycle:
for {
// all UDP packet data will be saved, channel where information about
// remote address and number of written bytes are stored, and a channel
// used to tell that buffer is ready to be overwritten.
-func ConnListen(conn *net.UDPConn) (chan *UDPPkt, []byte, chan struct{}) {
+func ConnListen(conn *net.UDPConn) (chan UDPPkt, []byte, chan struct{}) {
buf := make([]byte, MTU)
- sink := make(chan *UDPPkt)
+ sink := make(chan UDPPkt)
sinkReady := make(chan struct{})
go func(conn *net.UDPConn) {
var n int
n, addr, err = conn.ReadFromUDP(buf)
if err != nil {
// This is needed for ticking the timeouts counter outside
- sink <- nil
+ sink <- UDPPkt{nil, 0}
continue
}
- sink <- &UDPPkt{addr, n}
+ sink <- UDPPkt{addr, n}
}
}(conn)
sinkReady <- struct{}{}
return sink, buf, sinkReady
}
-func newNonceCipher(key *[KeySize]byte) *xtea.Cipher {
+func newNonceCipher(key *[32]byte) *xtea.Cipher {
nonceKey := make([]byte, 16)
salsa20.XORKeyStream(
nonceKey,
- make([]byte, KeySize),
+ make([]byte, 32),
make([]byte, xtea.BlockSize),
key,
)
return ciph
}
-func newPeer(addr *net.UDPAddr, id PeerId, nonce int, key *[KeySize]byte) *Peer {
+func cprCycleCalculate(rate int) time.Duration {
+ if rate == 0 {
+ return time.Duration(0)
+ }
+ return time.Second / time.Duration(rate*(1<<10)/MTU)
+}
+
+func newPeer(addr *net.UDPAddr, conf *PeerConf, nonce int, key *[SSize]byte) *Peer {
+ now := time.Now()
+ timeout := conf.Timeout
+ cprCycle := cprCycleCalculate(conf.CPR)
+ noiseEnable := conf.NoiseEnable
+ if conf.CPR > 0 {
+ noiseEnable = true
+ timeout = cprCycle
+ } else {
+ timeout = timeout / TimeoutHeartbeat
+ }
peer := Peer{
Addr: addr,
- LastPing: time.Now(),
- Id: id,
- NonceOur: uint64(Noncediff + nonce),
- NonceRecv: uint64(Noncediff + 0),
+ Timeout: timeout,
+ Established: now,
+ LastPing: now,
+ Id: conf.Id,
+ NoiseEnable: noiseEnable,
+ CPR: conf.CPR,
+ CPRCycle: cprCycle,
+ Noncediff: conf.Noncediff,
+ NonceOur: uint64(conf.Noncediff + nonce),
+ NonceRecv: uint64(conf.Noncediff + 0),
Key: key,
NonceCipher: newNonceCipher(key),
buf: make([]byte, MTU+S20BS),
tag: new([poly1305.TagSize]byte),
- keyAuth: new([KeySize]byte),
+ keyAuth: new([SSize]byte),
nonce: make([]byte, NonceSize),
}
return &peer
// ConnListen'es synchronization channel used to tell him that he is
// free to receive new packets. Authenticated and decrypted packets
// will be written to the interface immediately (except heartbeat ones).
-func (p *Peer) UDPProcess(udpPkt []byte, tap *TAP, ready chan struct{}) bool {
+func (p *Peer) UDPProcess(udpPkt []byte, tap io.Writer, ready chan struct{}) bool {
size := len(udpPkt)
- copy(p.buf[:KeySize], Emptiness)
+ copy(p.buf, Emptiness)
copy(p.tag[:], udpPkt[size-poly1305.TagSize:])
copy(p.buf[S20BS:], udpPkt[NonceSize:size-poly1305.TagSize])
salsa20.XORKeyStream(
udpPkt[:NonceSize],
p.Key,
)
- copy(p.keyAuth[:], p.buf[:KeySize])
+ copy(p.keyAuth[:], p.buf[:SSize])
if !poly1305.Verify(p.tag, udpPkt[:size-poly1305.TagSize], p.keyAuth) {
ready <- struct{}{}
p.FramesUnauth++
}
p.NonceCipher.Decrypt(p.buf, udpPkt[:NonceSize])
p.nonceRecv, _ = binary.Uvarint(p.buf[:NonceSize])
- if int(p.NonceRecv)-Noncediff >= 0 && int(p.nonceRecv) < int(p.NonceRecv)-Noncediff {
+ if int(p.NonceRecv)-p.Noncediff >= 0 && int(p.nonceRecv) < int(p.NonceRecv)-p.Noncediff {
ready <- struct{}{}
p.FramesDup++
return false
}
ready <- struct{}{}
+ p.FramesIn++
+ p.BytesIn += int64(size)
p.LastPing = time.Now()
p.NonceRecv = p.nonceRecv
- p.frame = p.buf[S20BS : S20BS+size-NonceSize-poly1305.TagSize]
- p.BytesIn += int64(len(p.frame))
- p.FramesIn++
- if subtle.ConstantTimeCompare(p.frame[:HeartbeatSize], HeartbeatMark) == 1 {
+ p.pktSize, _ = binary.Uvarint(p.buf[S20BS : S20BS+PktSizeSize])
+ if p.pktSize == 0 {
p.HeartbeatRecv++
return true
}
+ p.frame = p.buf[S20BS+PktSizeSize : S20BS+PktSizeSize+p.pktSize]
+ p.BytesPayloadIn += int64(p.pktSize)
tap.Write(p.frame)
return true
}
+type WriteToer interface {
+ WriteTo([]byte, net.Addr) (int, error)
+}
+
// Process incoming Ethernet packet.
// ethPkt is received data, conn is our outgoing connection.
// ready channel is TAPListen's synchronization channel used to tell him
// that he is free to receive new packets. Encrypted and authenticated
// packets will be sent to remote Peer side immediately.
-func (p *Peer) EthProcess(ethPkt []byte, conn *net.UDPConn, ready chan struct{}) {
+func (p *Peer) EthProcess(ethPkt []byte, conn WriteToer, ready chan struct{}) {
now := time.Now()
size := len(ethPkt)
// If this heartbeat is necessary
- if size == 0 && !p.LastSent.Add(heartbeatPeriodGet()).Before(now) {
+ if size == 0 && !p.LastSent.Add(p.Timeout).Before(now) {
return
}
- copy(p.buf[:KeySize], Emptiness)
+ copy(p.buf, Emptiness)
if size > 0 {
- copy(p.buf[S20BS:], ethPkt)
+ copy(p.buf[S20BS+PktSizeSize:], ethPkt)
ready <- struct{}{}
+ binary.PutUvarint(p.buf[S20BS:S20BS+PktSizeSize], uint64(size))
+ p.BytesPayloadOut += int64(size)
} else {
p.HeartbeatSent++
- copy(p.buf[S20BS:], HeartbeatMark)
- size = HeartbeatSize
}
- p.NonceOur = p.NonceOur + 2
+ p.NonceOur += 2
copy(p.nonce, Emptiness)
binary.PutUvarint(p.nonce, p.NonceOur)
p.NonceCipher.Encrypt(p.nonce, p.nonce)
salsa20.XORKeyStream(p.buf, p.buf, p.nonce, p.Key)
copy(p.buf[S20BS-NonceSize:S20BS], p.nonce)
- copy(p.keyAuth[:], p.buf[:KeySize])
- p.frame = p.buf[S20BS-NonceSize : S20BS+size]
+ copy(p.keyAuth[:], p.buf[:SSize])
+ if p.NoiseEnable {
+ p.frame = p.buf[S20BS-NonceSize : S20BS+MTU-NonceSize-poly1305.TagSize]
+ } else {
+ p.frame = p.buf[S20BS-NonceSize : S20BS+PktSizeSize+size]
+ }
poly1305.Sum(p.tag, p.frame, p.keyAuth)
- p.BytesOut += int64(len(p.frame))
+ p.BytesOut += int64(len(p.frame) + poly1305.TagSize)
p.FramesOut++
+
+ if p.CPRCycle != time.Duration(0) {
+ p.willSentCycle = p.LastSent.Add(p.CPRCycle)
+ if p.willSentCycle.After(now) {
+ time.Sleep(p.willSentCycle.Sub(now))
+ now = p.willSentCycle
+ }
+ }
p.LastSent = now
if _, err := conn.WriteTo(append(p.frame, p.tag[:]...), p.Addr); err != nil {
log.Println("Error sending UDP", err)