// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ldap
import (
"crypto/tls"
"errors"
"log"
"net"
"sync"
"github.com/SpruceHealth/asn1-ber"
)
const (
MessageQuit = 0
MessageRequest = 1
MessageResponse = 2
MessageFinish = 3
)
type messagePacket struct {
Op int
MessageID uint64
Packet *ber.Packet
Channel chan *ber.Packet
}
// LDAP Connection
type Conn struct {
conn net.Conn
isSSL bool
isClosing bool
Debug debugging
chanConfirm chan bool
chanResults map[uint64]chan *ber.Packet
chanMessage chan *messagePacket
chanMessageID chan uint64
wgSender sync.WaitGroup
wgClose sync.WaitGroup
once sync.Once
}
// Dial connects to the given address on the given network using net.Dial
// and then returns a new Conn for the connection.
func Dial(network, addr string) (*Conn, *Error) {
c, err := net.Dial(network, addr)
if err != nil {
return nil, NewError(ErrorNetwork, err)
}
conn := NewConn(c)
conn.start()
return conn, nil
}
// Dial connects to the given address on the given network using net.Dial
// and then sets up SSL connection and returns a new Conn for the connection.
func DialSSL(network, addr string, config *tls.Config) (*Conn, *Error) {
c, err := tls.Dial(network, addr, config)
if err != nil {
return nil, NewError(ErrorNetwork, err)
}
conn := NewConn(c)
conn.isSSL = true
conn.start()
return conn, nil
}
// Dial connects to the given address on the given network using net.Dial
// and then starts a TLS session and returns a new Conn for the connection.
func DialTLS(network, addr string, config *tls.Config) (*Conn, *Error) {
c, err := net.Dial(network, addr)
if err != nil {
return nil, NewError(ErrorNetwork, err)
}
conn := NewConn(c)
if err := conn.startTLS(config); err != nil {
conn.Close()
return nil, NewError(ErrorNetwork, err.Err)
}
conn.start()
return conn, nil
}
// NewConn returns a new Conn using conn for network I/O.
func NewConn(conn net.Conn) *Conn {
return &Conn{
conn: conn,
chanConfirm: make(chan bool),
chanMessageID: make(chan uint64),
chanMessage: make(chan *messagePacket, 10),
chanResults: map[uint64]chan *ber.Packet{},
}
}
func (l *Conn) start() {
go l.reader()
go l.processMessages()
l.wgClose.Add(1)
}
// Close closes the connection.
func (l *Conn) Close() {
l.once.Do(func() {
l.isClosing = true
l.wgSender.Wait()
l.Debug.Printf("Sending quit message and waiting for confirmation\n")
l.chanMessage <- &messagePacket{Op: MessageQuit}
<-l.chanConfirm
close(l.chanMessage)
l.Debug.Printf("Closing network connection\n")
if err := l.conn.Close(); err != nil {
log.Print(err)
}
l.conn = nil
l.wgClose.Done()
})
l.wgClose.Wait()
}
// Returns the next available messageID
func (l *Conn) nextMessageID() uint64 {
if l.chanMessageID != nil {
if messageID, ok := <-l.chanMessageID; ok {
return messageID
}
}
return 0
}
// StartTLS sends the command to start a TLS session and then creates a new TLS Client
func (l *Conn) startTLS(config *tls.Config) *Error {
messageID := l.nextMessageID()
if l.isSSL {
return NewError(ErrorNetwork, errors.New("Already encrypted"))
}
packet := ber.Encode(ber.ClassUniversal, ber.TypeConstructed, ber.TagSequence, nil, "LDAP Request")
packet.AppendChild(ber.NewInteger(ber.ClassUniversal, ber.TypePrimative, ber.TagInteger, messageID, "MessageID"))
request := ber.Encode(ber.ClassApplication, ber.TypeConstructed, ApplicationExtendedRequest, nil, "Start TLS")
request.AppendChild(ber.NewString(ber.ClassContext, ber.TypePrimative, 0, "1.3.6.1.4.1.1466.20037", "TLS Extended Command"))
packet.AppendChild(request)
l.Debug.PrintPacket(packet)
_, err := l.conn.Write(packet.Bytes())
if err != nil {
return NewError(ErrorNetwork, err)
}
packet, err = ber.ReadPacket(l.conn)
if err != nil {
return NewError(ErrorNetwork, err)
}
if l.Debug {
if err := addLDAPDescriptions(packet); err != nil {
return NewError(ErrorDebugging, err.Err)
}
ber.PrintPacket(packet)
}
if packet.Children[1].Children[0].Value.(uint64) == 0 {
conn := tls.Client(l.conn, config)
l.isSSL = true
l.conn = conn
}
return nil
}
func (l *Conn) sendMessage(packet *ber.Packet) (chan *ber.Packet, *Error) {
if l.isClosing {
return nil, NewError(ErrorNetwork, errors.New("Connection closed"))
}
out := make(chan *ber.Packet)
message := &messagePacket{
Op: MessageRequest,
MessageID: packet.Children[0].Value.(uint64),
Packet: packet,
Channel: out,
}
l.sendProcessMessage(message)
return out, nil
}
func (l *Conn) finishMessage(MessageID uint64) {
if l.isClosing {
return
}
message := &messagePacket{
Op: MessageFinish,
MessageID: MessageID,
}
l.sendProcessMessage(message)
}
func (l *Conn) sendProcessMessage(message *messagePacket) bool {
if l.isClosing {
return false
}
l.wgSender.Add(1)
l.chanMessage <- message
l.wgSender.Done()
return true
}
func (l *Conn) processMessages() {
defer func() {
for messageID, channel := range l.chanResults {
l.Debug.Printf("Closing channel for MessageID %d\n", messageID)
close(channel)
delete(l.chanResults, messageID)
}
close(l.chanMessageID)
l.chanConfirm <- true
close(l.chanConfirm)
}()
var messageID uint64 = 1
for {
select {
case l.chanMessageID <- messageID:
messageID++
case messagePacket, ok := <-l.chanMessage:
if !ok {
l.Debug.Printf("Shutting down - message channel is closed\n")
return
}
switch messagePacket.Op {
case MessageQuit:
l.Debug.Printf("Shutting down - quit message received\n")
return
case MessageRequest:
// Add to message list and write to network
l.Debug.Printf("Sending message %d\n", messagePacket.MessageID)
l.chanResults[messagePacket.MessageID] = messagePacket.Channel
// go routine
buf := messagePacket.Packet.Bytes()
for len(buf) > 0 {
n, err := l.conn.Write(buf)
if err != nil {
l.Debug.Printf("Error Sending Message: %s\n", err.Error())
break
}
// nothing else to send
if n == len(buf) {
break
}
// the remaining buf content
buf = buf[n:]
}
case MessageResponse:
l.Debug.Printf("Receiving message %d\n", messagePacket.MessageID)
if chanResult, ok := l.chanResults[messagePacket.MessageID]; ok {
chanResult <- messagePacket.Packet
} else {
log.Printf("Received unexpected message %d\n", messagePacket.MessageID)
ber.PrintPacket(messagePacket.Packet)
}
case MessageFinish:
// Remove from message list
l.Debug.Printf("Finished message %d\n", messagePacket.MessageID)
close(l.chanResults[messagePacket.MessageID])
delete(l.chanResults, messagePacket.MessageID)
}
}
}
}
func (l *Conn) reader() {
defer func() {
l.Close()
}()
for {
packet, err := ber.ReadPacket(l.conn)
if err != nil {
l.Debug.Printf("reader: %s\n", err.Error())
return
}
addLDAPDescriptions(packet)
message := &messagePacket{
Op: MessageResponse,
MessageID: packet.Children[0].Value.(uint64),
Packet: packet,
}
if !l.sendProcessMessage(message) {
return
}
}
}
