195 lines
5.3 KiB
Go
195 lines
5.3 KiB
Go
package main
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import (
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"encoding/hex"
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"math/rand"
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"net"
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"strings"
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"sync"
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"time"
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"github.com/VividCortex/ewma"
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"github.com/jedisct1/dlog"
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"golang.org/x/crypto/ed25519"
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)
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const (
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RTTEwmaDecay = 10.0
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DefaultPort = 443
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)
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type ServerInformalProperties uint64
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const (
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ServerInformalPropertyDNSSEC = ServerInformalProperties(1) << 0
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ServerInformalPropertyNoLog = ServerInformalProperties(1) << 1
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)
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type RegisteredServer struct {
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name string
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stamp ServerStamp
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}
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type ServerInfo struct {
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sync.RWMutex
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MagicQuery [8]byte
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ServerPk [32]byte
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SharedKey [32]byte
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CryptoConstruction CryptoConstruction
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Name string
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Timeout time.Duration
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UDPAddr *net.UDPAddr
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TCPAddr *net.TCPAddr
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lastActionTS time.Time
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rtt ewma.MovingAverage
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initialRtt int
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}
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type ServersInfo struct {
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sync.RWMutex
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inner []ServerInfo
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registeredServers []RegisteredServer
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}
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func (serversInfo *ServersInfo) registerServer(proxy *Proxy, name string, stamp ServerStamp) error {
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newRegisteredServer := RegisteredServer{name: name, stamp: stamp}
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serversInfo.Lock()
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defer serversInfo.Unlock()
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for i, oldRegisteredServer := range serversInfo.registeredServers {
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if oldRegisteredServer.name == name {
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serversInfo.registeredServers[i] = newRegisteredServer
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return nil
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}
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}
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serversInfo.registeredServers = append(serversInfo.registeredServers, newRegisteredServer)
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return nil
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}
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func (serversInfo *ServersInfo) refreshServer(proxy *Proxy, name string, stamp ServerStamp) error {
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serversInfo.Lock()
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defer serversInfo.Unlock()
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newServer, err := serversInfo.fetchServerInfo(proxy, name, stamp)
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if err != nil {
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return err
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}
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newServer.rtt = ewma.NewMovingAverage(RTTEwmaDecay)
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for i, oldServer := range serversInfo.inner {
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if oldServer.Name == newServer.Name {
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serversInfo.inner[i] = newServer
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return nil
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}
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}
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serversInfo.inner = append(serversInfo.inner, newServer)
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serversInfo.registeredServers = append(serversInfo.registeredServers, RegisteredServer{name: name, stamp: stamp})
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return nil
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}
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func (serversInfo *ServersInfo) refresh(proxy *Proxy) (int, error) {
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dlog.Infof("Refreshing certificates")
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serversInfo.RLock()
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registeredServers := serversInfo.registeredServers
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serversInfo.RUnlock()
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liveServers := 0
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var err error
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for _, registeredServer := range registeredServers {
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if err = serversInfo.refreshServer(proxy, registeredServer.name, registeredServer.stamp); err == nil {
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liveServers++
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}
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}
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serversInfo.Lock()
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inner := serversInfo.inner
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innerLen := len(inner)
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for i := 0; i < innerLen; i++ {
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for j := i + 1; j < innerLen; j++ {
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if inner[j].initialRtt < inner[i].initialRtt {
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inner[j], inner[i] = inner[i], inner[j]
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}
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}
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}
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serversInfo.inner = inner
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if innerLen > 1 {
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dlog.Noticef("Server with the lowest initial latency: %s (rtt: %dms)", inner[0].Name, inner[0].initialRtt)
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}
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serversInfo.Unlock()
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return liveServers, err
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}
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func (serversInfo *ServersInfo) liveServers() int {
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serversInfo.RLock()
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liveServers := len(serversInfo.inner)
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serversInfo.RUnlock()
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return liveServers
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}
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func (serversInfo *ServersInfo) getOne() *ServerInfo {
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serversInfo.Lock()
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defer serversInfo.Unlock()
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serversCount := len(serversInfo.inner)
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if serversCount <= 0 {
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return nil
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}
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candidate := rand.Intn(serversCount)
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if candidate == 0 {
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return &serversInfo.inner[candidate]
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}
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if serversInfo.inner[candidate].rtt.Value() < serversInfo.inner[0].rtt.Value() {
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serversInfo.inner[candidate], serversInfo.inner[0] = serversInfo.inner[0], serversInfo.inner[candidate]
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}
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candidate = rand.Intn(Max(Min(serversCount, 2), len(serversInfo.inner)))
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serverInfo := &serversInfo.inner[candidate]
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return serverInfo
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}
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func (serversInfo *ServersInfo) fetchServerInfo(proxy *Proxy, name string, stamp ServerStamp) (ServerInfo, error) {
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serverPk, err := hex.DecodeString(strings.Replace(stamp.serverPkStr, ":", "", -1))
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if err != nil || len(serverPk) != ed25519.PublicKeySize {
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dlog.Fatalf("Unsupported public key: [%v]", serverPk)
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}
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certInfo, rtt, err := FetchCurrentCert(proxy, &name, proxy.mainProto, serverPk, stamp.serverAddrStr, stamp.providerName)
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if err != nil {
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return ServerInfo{}, err
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}
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remoteUDPAddr, err := net.ResolveUDPAddr("udp", stamp.serverAddrStr)
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if err != nil {
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return ServerInfo{}, err
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}
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remoteTCPAddr, err := net.ResolveTCPAddr("tcp", stamp.serverAddrStr)
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if err != nil {
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return ServerInfo{}, err
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}
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serverInfo := ServerInfo{
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MagicQuery: certInfo.MagicQuery,
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ServerPk: certInfo.ServerPk,
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SharedKey: certInfo.SharedKey,
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CryptoConstruction: certInfo.CryptoConstruction,
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Name: name,
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Timeout: proxy.timeout,
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UDPAddr: remoteUDPAddr,
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TCPAddr: remoteTCPAddr,
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initialRtt: rtt,
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}
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return serverInfo, nil
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}
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func (serverInfo *ServerInfo) noticeFailure(proxy *Proxy) {
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serverInfo.Lock()
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serverInfo.rtt.Set(float64(proxy.timeout.Nanoseconds()))
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serverInfo.Unlock()
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}
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func (serverInfo *ServerInfo) noticeBegin(proxy *Proxy) {
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serverInfo.Lock()
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serverInfo.lastActionTS = time.Now()
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serverInfo.Unlock()
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}
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func (serverInfo *ServerInfo) noticeSuccess(proxy *Proxy) {
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now := time.Now()
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serverInfo.Lock()
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elapsed := now.Sub(serverInfo.lastActionTS) / 1024
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if elapsed > 0 {
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serverInfo.rtt.Add(float64(elapsed))
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}
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serverInfo.Unlock()
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}
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