// Connects to a remote node and negotiates a session.
func Dial(host string, port int, key *rsa.PrivateKey) (*Session, error) {
// Open the stream connection
addr := fmt.Sprintf("%s:%d", host, port)
strm, err := stream.Dial(addr, config.SessionDialTimeout)
if err != nil {
return nil, err
}
// Set up the authenticated session
secret, err := clientAuth(strm, key)
if err != nil {
log.Printf("session: failed to authenticate connection: %v.", err)
if err := strm.Close(); err != nil {
log.Printf("session: failed to close unauthenticated connection: %v.", err)
}
}
// Link a new data connection to it
sess := newSession(strm, secret, false)
if err = clientLink(sess); err != nil {
log.Printf("session: failed to link data connection: %v.", err)
if err := strm.Close(); err != nil {
log.Printf("session: failed to close unlinked connection: %v.", err)
}
return nil, err
}
return sess, nil
}
func client(msg string, ch chan string) {
// Open a TCP connection to the stream server
addr := fmt.Sprintf("%s:%d", host, port)
strm, err := stream.Dial(addr, time.Second)
if err != nil {
fmt.Println("Failed to connect to stream server:", err)
return
}
defer strm.Close()
// Send the message and receive a reply
if err = strm.Send(msg); err != nil {
fmt.Println("Failed to send the message:", err)
return
}
if err = strm.Flush(); err != nil {
fmt.Println("Failed to flush the message:", err)
return
}
if err = strm.Recv(&msg); err != nil {
fmt.Println("Failed to receive the reply:", err)
return
}
// Return the reply to the caller and terminate
ch <- msg
}
// Accepts an incoming tunneling request from a remote, initializes and stores
// the new tunnel into the connection state.
func (c *Connection) buildTunnel(remote uint64, id uint64, key []byte, addrs []string, timeout time.Duration) (*Tunnel, error) {
deadline := time.Now().Add(timeout)
// Create the local tunnel endpoint
c.tunLock.Lock()
tunId := c.tunIdx
tun := &Tunnel{
id: tunId,
owner: c,
term: make(chan struct{}),
}
c.tunIdx++
c.tunLive[tunId] = tun
c.tunLock.Unlock()
// Dial the remote tunnel listener
var err error
var strm *stream.Stream
for _, addr := range addrs {
strm, err = stream.Dial(addr, timeout)
if err == nil {
break
}
}
// If no error occurred, initialize the client endpoint
if err == nil {
var conn *link.Link
conn, err = c.initClientTunnel(strm, remote, id, key, deadline)
if err != nil {
if err := strm.Close(); err != nil {
log.Printf("iris: failed to close uninitialized client tunnel stream: %v.", err)
}
} else {
// Make sure the tunnel wasn't terminated since (init/close race)
tun.lock.Lock()
select {
case <-tun.term:
conn.Close()
err = ErrTerminating
default:
tun.conn = conn
}
tun.lock.Unlock()
}
}
// Tunneling failed, clean up and report error
if err != nil {
c.tunLock.Lock()
delete(c.tunLive, tunId)
c.tunLock.Unlock()
return nil, err
}
return tun, nil
}
// Initiates a data channel link to the specified control channel.
func clientLink(sess *Session) error {
// Wait for the server to specify the session id
msg, err := sess.CtrlLink.RecvDirect()
if err != nil {
return fmt.Errorf("failed to retrieve session id: %v", err)
}
// Initiate a new stream connection to the server
addr := sess.CtrlLink.Sock().RemoteAddr().String()
strm, err := stream.Dial(addr, config.SessionDialTimeout)
if err != nil {
return fmt.Errorf("failed to establish data link: %v", err)
}
// Send the temporary id back on the data stream
req := &initRequest{
Link: &linkRequest{msg.Head.Meta.(*linkRequest).Id},
}
if err = strm.Send(req); err != nil {
strm.Close()
return fmt.Errorf("failed to send link request: %v", err)
}
if err = strm.Flush(); err != nil {
strm.Close()
return fmt.Errorf("failed to flush link request: %v", err)
}
// Finalize the session with the data stream
sess.init(strm, false)
// Send the data link authentication
auth := &proto.Message{
Head: proto.Header{
Meta: req.Link,
},
}
// Retrieve the remote data link authentication
if err = sess.DataLink.SendDirect(auth); err != nil {
return fmt.Errorf("failed to send data auth: %v", err)
}
if msg, err := sess.DataLink.RecvDirect(); err != nil {
return fmt.Errorf("failed to retrieve data auth: %v", err)
} else if res, ok := msg.Head.Meta.(*linkRequest); !ok {
return errors.New("corrupt authentication message")
} else if res.Id != req.Link.Id {
return errors.New("mismatched authentication message")
}
return nil
}
// Tests the low level send and receive methods.
func TestDirectSendRecv(t *testing.T) {
t.Parallel()
// Start a stream listener
addr, err := net.ResolveTCPAddr("tcp", "localhost:0")
if err != nil {
t.Fatalf("failed to resolve local address: %v.", err)
}
listener, err := stream.Listen(addr)
if err != nil {
t.Fatalf("failed to listen for incoming streams: %v.", err)
}
listener.Accept(10 * time.Millisecond)
defer listener.Close()
// Establish a stream connection to the listener
host := fmt.Sprintf("%s:%d", "localhost", addr.Port)
clientStrm, err := stream.Dial(host, time.Millisecond)
if err != nil {
t.Fatalf("failed to connect to stream listener: %v.", err)
}
serverStrm := <-listener.Sink
defer clientStrm.Close()
defer serverStrm.Close()
// Initialize the stream based encrypted links
secret := make([]byte, 16)
io.ReadFull(rand.Reader, secret)
clientHKDF := hkdf.New(sha1.New, secret, []byte("HKDF salt"), []byte("HKDF info"))
serverHKDF := hkdf.New(sha1.New, secret, []byte("HKDF salt"), []byte("HKDF info"))
clientLink := New(clientStrm, clientHKDF, false)
serverLink := New(serverStrm, serverHKDF, true)
// Generate some random messages and pass around both ways
for i := 0; i < 1000; i++ {
// Generate the message to send
send := &proto.Message{
Head: proto.Header{
Meta: make([]byte, 32),
},
Data: make([]byte, 32),
}
io.ReadFull(rand.Reader, send.Head.Meta.([]byte))
io.ReadFull(rand.Reader, send.Data)
send.Encrypt()
// Send the message from client to server
if err := clientLink.SendDirect(send); err != nil {
t.Fatalf("failed to send message to server: %v.", err)
}
if recv, err := serverLink.RecvDirect(); err != nil {
t.Fatalf("failed to receive message from client: %v.", err)
} else if bytes.Compare(send.Head.Meta.([]byte), recv.Head.Meta.([]byte)) != 0 || bytes.Compare(send.Data, recv.Data) != 0 {
t.Fatalf("send/receive mismatch: have %+v, want %+v.", recv, send)
}
// Send the message from server to client
if err := serverLink.SendDirect(send); err != nil {
t.Fatalf("failed to send message to client: %v.", err)
}
if recv, err := clientLink.RecvDirect(); err != nil {
t.Fatalf("failed to receive message from server: %v.", err)
} else if bytes.Compare(send.Head.Meta.([]byte), recv.Head.Meta.([]byte)) != 0 || bytes.Compare(send.Data, recv.Data) != 0 {
t.Fatalf("send/receive mismatch: have %+v, want %+v.", recv, send)
}
}
}