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dendrite/cmd/dendrite-demo-yggdrasil/yggconn/session.go

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// Copyright 2020 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package yggconn
import (
"context"
"crypto/rand"
"crypto/rsa"
"crypto/tls"
"crypto/x509"
"crypto/x509/pkix"
"encoding/hex"
"encoding/pem"
"errors"
"fmt"
"math/big"
"net"
"time"
"github.com/lucas-clemente/quic-go"
"github.com/yggdrasil-network/yggdrasil-go/src/crypto"
"github.com/yggdrasil-network/yggdrasil-go/src/yggdrasil"
)
type session struct {
node *Node
session quic.Session
address string
context context.Context
cancel context.CancelFunc
}
func (n *Node) newSession(sess quic.Session, address string) *session {
ctx, cancel := context.WithCancel(context.TODO())
return &session{
node: n,
session: sess,
address: address,
context: ctx,
cancel: cancel,
}
}
func (s *session) kill() {
s.cancel()
}
func (n *Node) listenFromYgg() {
var err error
n.listener, err = quic.Listen(
n.core, // yggdrasil.PacketConn
n.tlsConfig, // TLS config
n.quicConfig, // QUIC config
)
if err != nil {
panic(err)
}
for {
n.log.Infoln("Waiting to accept QUIC sessions")
session, err := n.listener.Accept(context.TODO())
if err != nil {
n.log.Println("n.listener.Accept:", err)
return
}
if len(session.ConnectionState().PeerCertificates) != 1 {
_ = session.CloseWithError(0, "expected a peer certificate")
continue
}
address := session.ConnectionState().PeerCertificates[0].DNSNames[0]
n.log.Infoln("Accepted connection from", address)
go n.newSession(session, address).listenFromQUIC()
go n.sessionFunc(address)
}
}
func (s *session) listenFromQUIC() {
if existing, ok := s.node.sessions.Load(s.address); ok {
if existingSession, ok := existing.(*session); ok {
fmt.Println("Killing existing session to replace", s.address)
existingSession.kill()
}
}
s.node.sessionCount.Inc()
s.node.sessions.Store(s.address, s)
defer s.node.sessions.Delete(s.address)
defer s.node.sessionCount.Dec()
for {
st, err := s.session.AcceptStream(s.context)
if err != nil {
s.node.log.Println("session.AcceptStream:", err)
return
}
s.node.incoming <- QUICStream{st, s.session}
}
}
// Implements net.Listener
func (n *Node) Accept() (net.Conn, error) {
return <-n.incoming, nil
}
// Implements net.Listener
func (n *Node) Close() error {
return n.listener.Close()
}
// Implements net.Listener
func (n *Node) Addr() net.Addr {
return n.listener.Addr()
}
// Implements http.Transport.Dial
func (n *Node) Dial(network, address string) (net.Conn, error) {
return n.DialContext(context.TODO(), network, address)
}
// Implements http.Transport.DialContext
func (n *Node) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
s, ok1 := n.sessions.Load(address)
session, ok2 := s.(*session)
if !ok1 || !ok2 {
// First of all, check if we think we know the coords of this
// node. If we do then we'll try to dial to it directly. This
// will either succeed or fail.
if v, ok := n.coords.Load(address); ok {
coords, ok := v.(yggdrasil.Coords)
if !ok {
n.coords.Delete(address)
return nil, errors.New("should have found yggdrasil.Coords but didn't")
}
n.log.Infof("Coords %s for %q cached, trying to dial", coords.String(), address)
var err error
// We think we know the coords. Try to dial the node.
if session, err = n.tryDial(address, coords); err != nil {
// We thought we knew the coords but it didn't result
// in a successful dial. Nuke them from the cache.
n.coords.Delete(address)
n.log.Infof("Cached coords %s for %q failed", coords.String(), address)
}
}
// We either don't know the coords for the node, or we failed
// to dial it before, in which case try to resolve the coords.
if _, ok := n.coords.Load(address); !ok {
var coords yggdrasil.Coords
var err error
// First look and see if the node is something that we already
// know about from our direct switch peers.
for _, peer := range n.core.GetSwitchPeers() {
if peer.PublicKey.String() == address {
coords = peer.Coords
n.log.Infof("%q is a direct peer, coords are %s", address, coords.String())
n.coords.Store(address, coords)
break
}
}
// If it isn' a node that we know directly then try to search
// the network.
if coords == nil {
n.log.Infof("Searching for coords for %q", address)
dest, derr := hex.DecodeString(address)
if derr != nil {
return nil, derr
}
if len(dest) != crypto.BoxPubKeyLen {
return nil, errors.New("invalid key length supplied")
}
var pubKey crypto.BoxPubKey
copy(pubKey[:], dest)
nodeID := crypto.GetNodeID(&pubKey)
nodeMask := &crypto.NodeID{}
for i := range nodeMask {
nodeMask[i] = 0xFF
}
fmt.Println("Resolving coords")
coords, err = n.core.Resolve(nodeID, nodeMask)
if err != nil {
return nil, fmt.Errorf("n.core.Resolve: %w", err)
}
fmt.Println("Found coords:", coords)
n.coords.Store(address, coords)
}
// We now know the coords in theory. Let's try dialling the
// node again.
if session, err = n.tryDial(address, coords); err != nil {
return nil, fmt.Errorf("n.tryDial: %w", err)
}
}
}
if session == nil {
return nil, fmt.Errorf("should have found session but didn't")
}
st, err := session.session.OpenStream()
if err != nil {
n.log.Println("session.OpenStream:", err)
_ = session.session.CloseWithError(0, "expected to be able to open session")
return nil, err
}
return QUICStream{st, session.session}, nil
}
func (n *Node) tryDial(address string, coords yggdrasil.Coords) (*session, error) {
quicSession, err := quic.Dial(
n.core, // yggdrasil.PacketConn
coords, // dial address
address, // dial SNI
n.tlsConfig, // TLS config
n.quicConfig, // QUIC config
)
if err != nil {
return nil, err
}
if len(quicSession.ConnectionState().PeerCertificates) != 1 {
_ = quicSession.CloseWithError(0, "expected a peer certificate")
return nil, errors.New("didn't receive a peer certificate")
}
if len(quicSession.ConnectionState().PeerCertificates[0].DNSNames) != 1 {
_ = quicSession.CloseWithError(0, "expected a DNS name")
return nil, errors.New("didn't receive a DNS name")
}
if gotAddress := quicSession.ConnectionState().PeerCertificates[0].DNSNames[0]; address != gotAddress {
_ = quicSession.CloseWithError(0, "you aren't the host I was hoping for")
return nil, fmt.Errorf("expected %q but dialled %q", address, gotAddress)
}
session := n.newSession(quicSession, address)
go session.listenFromQUIC()
go n.sessionFunc(address)
return session, nil
}
func (n *Node) generateTLSConfig() *tls.Config {
key, err := rsa.GenerateKey(rand.Reader, 1024)
if err != nil {
panic(err)
}
template := x509.Certificate{
Subject: pkix.Name{
CommonName: n.DerivedServerName(),
},
SerialNumber: big.NewInt(1),
NotAfter: time.Now().Add(time.Hour * 24 * 365),
DNSNames: []string{n.DerivedSessionName()},
}
certDER, err := x509.CreateCertificate(rand.Reader, &template, &template, &key.PublicKey, key)
if err != nil {
panic(err)
}
keyPEM := pem.EncodeToMemory(&pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)})
certPEM := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: certDER})
tlsCert, err := tls.X509KeyPair(certPEM, keyPEM)
if err != nil {
panic(err)
}
return &tls.Config{
Certificates: []tls.Certificate{tlsCert},
NextProtos: []string{"quic-matrix-ygg"},
InsecureSkipVerify: true,
ClientAuth: tls.RequireAnyClientCert,
GetClientCertificate: func(info *tls.CertificateRequestInfo) (*tls.Certificate, error) {
return &tlsCert, nil
},
}
}