func (y *Conn) receiveCall(session uint32,
tube tube.TubedConn) (subject string, rwc io.ReadWriteCloser, err os.Error) {
u_subject := &U_Subject{}
err = tube.Decode(u_subject)
if err != nil || u_subject.Subject == "" || y.setRegime(regimeBusy) != nil {
err = y.kill(os.ErrorString("d,conn: receive call"))
return "", nil, err
}
//fmt.Printf(term.FgCyan + "d·conn[%#p] —— ring! subject=%s\n"+term.Reset, y, u_subject.Subject)
y.hlk.Lock()
h := newHandoff(y, session, func() {
y.setRegime(regimeReady)
y.lk.Lock()
y.h = nil
y.lk.Unlock()
y.hlk.Unlock()
})
y.lk.Lock()
y.h = h
y.lk.Unlock()
return u_subject.Subject, h, nil
}
// authHello establishes a symmetrically encrypted channel over t
func authHello(t tube.TubedConn) (tube.TubedConn, os.Error) {
// Make my hello private key
HelloA := GenerateHelloKey()
HelloA_proto := HelloA.Proto()
// Send my hello public key
err := t.Encode(HelloA_proto)
if err != nil {
return nil, err
}
// Receive their hello public key
HelloB_proto := &U_HelloKey{}
err = t.Decode(HelloB_proto)
if err != nil {
return nil, err
}
HelloB, err := UnprotoHelloPubKey(HelloB_proto)
if err != nil {
return nil, err
}
// Make my session key half
HalvesA := GenerateKeyHalves()
// Encrypt my session key half with their intro public key
HalvesA_HelloB, err := crypto.EncryptShortMsg(HelloB.RSAPubKey(),
HalvesA.Bytes(), []byte("key-halves"))
if err != nil {
return nil, err
}
// Send my encrypted session half key
err = t.Encode(&U_KeyHalves{HalvesA_HelloB})
if err != nil {
return nil, err
}
// Receive their session key half, encrypted with my intro private key
HalvesB_HelloA_proto := &U_KeyHalves{}
err = t.Decode(HalvesB_HelloA_proto)
if err != nil {
return nil, err
}
// Decrypt their session key half
HalvesB_bytes, err := crypto.DecryptShortMsg(HelloA.RSAPrivKey(),
HalvesB_HelloA_proto.Halves, []byte("key-halves"))
if err != nil {
return nil, err
}
HalvesB, err := BytesToKeyHalves(HalvesB_bytes)
if err != nil {
return nil, err
}
// Compute session keys me->them and them->me
keyAB := makeSessionKey("SK", HalvesA.Bytes(), HalvesB.Bytes(),
HelloA.RSAPubKey(), HelloB.RSAPubKey())
keyBA := makeSessionKey("SK", HalvesB.Bytes(), HalvesA.Bytes(),
HelloB.RSAPubKey(), HelloA.RSAPubKey())
// Create encrypted tube
return tube.NewRC4Tube(t, keyBA, keyAB), nil
}