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listener.go
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listener.go
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package kcp
import (
"crypto/tls"
"net"
"sync"
"time"
"v2ray.com/core/common/alloc"
"v2ray.com/core/common/log"
v2net "v2ray.com/core/common/net"
"v2ray.com/core/common/serial"
"v2ray.com/core/proxy"
"v2ray.com/core/transport/internet"
v2tls "v2ray.com/core/transport/internet/tls"
"v2ray.com/core/transport/internet/udp"
)
// Listener defines a server listening for connections
type Listener struct {
sync.Mutex
running bool
authenticator internet.Authenticator
sessions map[string]*Connection
awaitingConns chan *Connection
hub *udp.UDPHub
tlsConfig *tls.Config
config *Config
}
func NewListener(address v2net.Address, port v2net.Port, options internet.ListenOptions) (*Listener, error) {
networkSettings, err := options.Stream.GetEffectiveNetworkSettings()
if err != nil {
log.Error("KCP|Listener: Failed to get KCP settings: ", err)
return nil, err
}
kcpSettings := networkSettings.(*Config)
auth, err := kcpSettings.GetAuthenticator()
if err != nil {
return nil, err
}
l := &Listener{
authenticator: auth,
sessions: make(map[string]*Connection),
awaitingConns: make(chan *Connection, 64),
running: true,
config: kcpSettings,
}
if options.Stream != nil && options.Stream.HasSecuritySettings() {
securitySettings, err := options.Stream.GetEffectiveSecuritySettings()
if err != nil {
log.Error("KCP|Listener: Failed to get security settings: ", err)
return nil, err
}
switch securitySettings := securitySettings.(type) {
case *v2tls.Config:
l.tlsConfig = securitySettings.GetTLSConfig()
}
}
hub, err := udp.ListenUDP(address, port, udp.ListenOption{Callback: l.OnReceive})
if err != nil {
return nil, err
}
l.hub = hub
log.Info("KCP|Listener: listening on ", address, ":", port)
return l, nil
}
func (this *Listener) OnReceive(payload *alloc.Buffer, session *proxy.SessionInfo) {
defer payload.Release()
src := session.Source
if valid := this.authenticator.Open(payload); !valid {
log.Info("KCP|Listener: discarding invalid payload from ", src)
return
}
if !this.running {
return
}
this.Lock()
defer this.Unlock()
if !this.running {
return
}
if payload.Len() < 4 {
return
}
conv := serial.BytesToUint16(payload.Value)
cmd := Command(payload.Value[2])
sourceId := src.NetAddr() + "|" + serial.Uint16ToString(conv)
conn, found := this.sessions[sourceId]
if !found {
if cmd == CommandTerminate {
return
}
log.Debug("KCP|Listener: Creating session with id(", sourceId, ") from ", src)
writer := &Writer{
id: sourceId,
hub: this.hub,
dest: src,
listener: this,
}
srcAddr := &net.UDPAddr{
IP: src.Address.IP(),
Port: int(src.Port),
}
auth, err := this.config.GetAuthenticator()
if err != nil {
log.Error("KCP|Listener: Failed to create authenticator: ", err)
}
conn = NewConnection(conv, writer, this.Addr().(*net.UDPAddr), srcAddr, auth, this.config)
select {
case this.awaitingConns <- conn:
case <-time.After(time.Second * 5):
conn.Close()
return
}
this.sessions[sourceId] = conn
}
conn.Input(payload.Value)
}
func (this *Listener) Remove(dest string) {
if !this.running {
return
}
this.Lock()
defer this.Unlock()
if !this.running {
return
}
log.Debug("KCP|Listener: Removing session ", dest)
delete(this.sessions, dest)
}
// Accept implements the Accept method in the Listener interface; it waits for the next call and returns a generic Conn.
func (this *Listener) Accept() (internet.Connection, error) {
for {
if !this.running {
return nil, ErrClosedListener
}
select {
case conn, open := <-this.awaitingConns:
if !open {
break
}
if this.tlsConfig != nil {
tlsConn := tls.Server(conn, this.tlsConfig)
return v2tls.NewConnection(tlsConn), nil
}
return conn, nil
case <-time.After(time.Second):
}
}
}
// Close stops listening on the UDP address. Already Accepted connections are not closed.
func (this *Listener) Close() error {
if !this.running {
return ErrClosedListener
}
this.Lock()
defer this.Unlock()
this.running = false
close(this.awaitingConns)
for _, conn := range this.sessions {
go conn.Terminate()
}
this.hub.Close()
return nil
}
func (this *Listener) ActiveConnections() int {
this.Lock()
defer this.Unlock()
return len(this.sessions)
}
// Addr returns the listener's network address, The Addr returned is shared by all invocations of Addr, so do not modify it.
func (this *Listener) Addr() net.Addr {
return this.hub.Addr()
}
type Writer struct {
id string
dest v2net.Destination
hub *udp.UDPHub
listener *Listener
}
func (this *Writer) Write(payload []byte) (int, error) {
return this.hub.WriteTo(payload, this.dest)
}
func (this *Writer) Close() error {
this.listener.Remove(this.id)
return nil
}
func ListenKCP(address v2net.Address, port v2net.Port, options internet.ListenOptions) (internet.Listener, error) {
return NewListener(address, port, options)
}
func init() {
internet.KCPListenFunc = ListenKCP
}