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package p2p
import (
"context"
"errors"
"fmt"
"io"
"math"
"net"
"strconv"
"sync"
"golang.org/x/net/netutil"
"github.com/tendermint/tendermint/crypto"
"github.com/tendermint/tendermint/internal/libs/protoio"
"github.com/tendermint/tendermint/internal/p2p/conn"
"github.com/tendermint/tendermint/libs/log"
p2pproto "github.com/tendermint/tendermint/proto/tendermint/p2p"
"github.com/tendermint/tendermint/types"
)
const (
MConnProtocol Protocol = "mconn"
TCPProtocol Protocol = "tcp"
)
// MConnTransportOptions sets options for MConnTransport.
type MConnTransportOptions struct {
// MaxAcceptedConnections is the maximum number of simultaneous accepted
// (incoming) connections. Beyond this, new connections will block until
// a slot is free. 0 means unlimited.
//
// FIXME: We may want to replace this with connection accounting in the
// Router, since it will need to do e.g. rate limiting and such as well.
// But it might also make sense to have per-transport limits.
MaxAcceptedConnections uint32
}
// MConnTransport is a Transport implementation using the current multiplexed
// Tendermint protocol ("MConn").
type MConnTransport struct {
logger log.Logger
options MConnTransportOptions
mConnConfig conn.MConnConfig
channelDescs []*ChannelDescriptor
closeOnce sync.Once
doneCh chan struct{}
listener net.Listener
}
// NewMConnTransport sets up a new MConnection transport. This uses the
// proprietary Tendermint MConnection protocol, which is implemented as
// conn.MConnection.
func NewMConnTransport(
logger log.Logger,
mConnConfig conn.MConnConfig,
channelDescs []*ChannelDescriptor,
options MConnTransportOptions,
) *MConnTransport {
return &MConnTransport{
logger: logger,
options: options,
mConnConfig: mConnConfig,
doneCh: make(chan struct{}),
channelDescs: channelDescs,
}
}
// String implements Transport.
func (m *MConnTransport) String() string {
return string(MConnProtocol)
}
// Protocols implements Transport. We support tcp for backwards-compatibility.
func (m *MConnTransport) Protocols() []Protocol {
return []Protocol{MConnProtocol, TCPProtocol}
}
// Endpoints implements Transport.
func (m *MConnTransport) Endpoints() []Endpoint {
if m.listener == nil {
return []Endpoint{}
}
select {
case <-m.doneCh:
return []Endpoint{}
default:
}
endpoint := Endpoint{
Protocol: MConnProtocol,
}
if addr, ok := m.listener.Addr().(*net.TCPAddr); ok {
endpoint.IP = addr.IP
endpoint.Port = uint16(addr.Port)
}
return []Endpoint{endpoint}
}
// Listen asynchronously listens for inbound connections on the given endpoint.
// It must be called exactly once before calling Accept(), and the caller must
// call Close() to shut down the listener.
//
// FIXME: Listen currently only supports listening on a single endpoint, it
// might be useful to support listening on multiple addresses (e.g. IPv4 and
// IPv6, or a private and public address) via multiple Listen() calls.
func (m *MConnTransport) Listen(endpoint Endpoint) error {
if m.listener != nil {
return errors.New("transport is already listening")
}
if err := m.validateEndpoint(endpoint); err != nil {
return err
}
listener, err := net.Listen("tcp", net.JoinHostPort(
endpoint.IP.String(), strconv.Itoa(int(endpoint.Port))))
if err != nil {
return err
}
if m.options.MaxAcceptedConnections > 0 {
// FIXME: This will establish the inbound connection but simply hang it
// until another connection is released. It would probably be better to
// return an error to the remote peer or close the connection. This is
// also a DoS vector since the connection will take up kernel resources.
// This was just carried over from the legacy P2P stack.
listener = netutil.LimitListener(listener, int(m.options.MaxAcceptedConnections))
}
m.listener = listener
return nil
}
// Accept implements Transport.
func (m *MConnTransport) Accept(ctx context.Context) (Connection, error) {
if m.listener == nil {
return nil, errors.New("transport is not listening")
}
conCh := make(chan net.Conn)
errCh := make(chan error)
go func() {
tcpConn, err := m.listener.Accept()
if err != nil {
select {
case errCh <- err:
case <-ctx.Done():
}
}
select {
case conCh <- tcpConn:
case <-ctx.Done():
}
}()
select {
case <-ctx.Done():
m.listener.Close()
return nil, io.EOF
case <-m.doneCh:
m.listener.Close()
return nil, io.EOF
case err := <-errCh:
return nil, err
case tcpConn := <-conCh:
return newMConnConnection(m.logger, tcpConn, m.mConnConfig, m.channelDescs), nil
}
}
// Dial implements Transport.
func (m *MConnTransport) Dial(ctx context.Context, endpoint Endpoint) (Connection, error) {
if err := m.validateEndpoint(endpoint); err != nil {
return nil, err
}
if endpoint.Port == 0 {
endpoint.Port = 26657
}
dialer := net.Dialer{}
tcpConn, err := dialer.DialContext(ctx, "tcp", net.JoinHostPort(
endpoint.IP.String(), strconv.Itoa(int(endpoint.Port))))
if err != nil {
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
return nil, err
}
}
return newMConnConnection(m.logger, tcpConn, m.mConnConfig, m.channelDescs), nil
}
// Close implements Transport.
func (m *MConnTransport) Close() error {
var err error
m.closeOnce.Do(func() {
close(m.doneCh)
if m.listener != nil {
err = m.listener.Close()
}
})
return err
}
// SetChannels sets the channel descriptors to be used when
// establishing a connection.
//
// FIXME: To be removed when the legacy p2p stack is removed. Channel
// descriptors should be managed by the router. The underlying transport and
// connections should be agnostic to everything but the channel ID's which are
// initialized in the handshake.
func (m *MConnTransport) AddChannelDescriptors(channelDesc []*ChannelDescriptor) {
m.channelDescs = append(m.channelDescs, channelDesc...)
}
// validateEndpoint validates an endpoint.
func (m *MConnTransport) validateEndpoint(endpoint Endpoint) error {
if err := endpoint.Validate(); err != nil {
return err
}
if endpoint.Protocol != MConnProtocol && endpoint.Protocol != TCPProtocol {
return fmt.Errorf("unsupported protocol %q", endpoint.Protocol)
}
if len(endpoint.IP) == 0 {
return errors.New("endpoint has no IP address")
}
if endpoint.Path != "" {
return fmt.Errorf("endpoints with path not supported (got %q)", endpoint.Path)
}
return nil
}
// mConnConnection implements Connection for MConnTransport.
type mConnConnection struct {
logger log.Logger
conn net.Conn
mConnConfig conn.MConnConfig
channelDescs []*ChannelDescriptor
receiveCh chan mConnMessage
errorCh chan error
doneCh chan struct{}
closeOnce sync.Once
mconn *conn.MConnection // set during Handshake()
}
// mConnMessage passes MConnection messages through internal channels.
type mConnMessage struct {
channelID ChannelID
payload []byte
}
// newMConnConnection creates a new mConnConnection.
func newMConnConnection(
logger log.Logger,
conn net.Conn,
mConnConfig conn.MConnConfig,
channelDescs []*ChannelDescriptor,
) *mConnConnection {
return &mConnConnection{
logger: logger,
conn: conn,
mConnConfig: mConnConfig,
channelDescs: channelDescs,
receiveCh: make(chan mConnMessage),
errorCh: make(chan error, 1), // buffered to avoid onError leak
doneCh: make(chan struct{}),
}
}
// Handshake implements Connection.
func (c *mConnConnection) Handshake(
ctx context.Context,
nodeInfo types.NodeInfo,
privKey crypto.PrivKey,
) (types.NodeInfo, crypto.PubKey, error) {
var (
mconn *conn.MConnection
peerInfo types.NodeInfo
peerKey crypto.PubKey
errCh = make(chan error, 1)
)
// To handle context cancellation, we need to do the handshake in a
// goroutine and abort the blocking network calls by closing the connection
// when the context is canceled.
go func() {
// FIXME: Since the MConnection code panics, we need to recover it and turn it
// into an error. We should remove panics instead.
defer func() {
if r := recover(); r != nil {
errCh <- fmt.Errorf("recovered from panic: %v", r)
}
}()
var err error
mconn, peerInfo, peerKey, err = c.handshake(ctx, nodeInfo, privKey)
select {
case errCh <- err:
case <-ctx.Done():
}
}()
select {
case <-ctx.Done():
_ = c.Close()
return types.NodeInfo{}, nil, ctx.Err()
case err := <-errCh:
if err != nil {
return types.NodeInfo{}, nil, err
}
c.mconn = mconn
if err = c.mconn.Start(ctx); err != nil {
return types.NodeInfo{}, nil, err
}
return peerInfo, peerKey, nil
}
}
// handshake is a helper for Handshake, simplifying error handling so we can
// keep context handling and panic recovery in Handshake. It returns an
// unstarted but handshaked MConnection, to avoid concurrent field writes.
func (c *mConnConnection) handshake(
ctx context.Context,
nodeInfo types.NodeInfo,
privKey crypto.PrivKey,
) (*conn.MConnection, types.NodeInfo, crypto.PubKey, error) {
if c.mconn != nil {
return nil, types.NodeInfo{}, nil, errors.New("connection is already handshaked")
}
secretConn, err := conn.MakeSecretConnection(c.conn, privKey)
if err != nil {
return nil, types.NodeInfo{}, nil, err
}
wg := &sync.WaitGroup{}
var pbPeerInfo p2pproto.NodeInfo
errCh := make(chan error, 2)
wg.Add(1)
go func() {
defer wg.Done()
_, err := protoio.NewDelimitedWriter(secretConn).WriteMsg(nodeInfo.ToProto())
select {
case errCh <- err:
case <-ctx.Done():
}
}()
wg.Add(1)
go func() {
defer wg.Done()
_, err := protoio.NewDelimitedReader(secretConn, types.MaxNodeInfoSize()).ReadMsg(&pbPeerInfo)
select {
case errCh <- err:
case <-ctx.Done():
}
}()
wg.Wait()
if err, ok := <-errCh; ok && err != nil {
return nil, types.NodeInfo{}, nil, err
}
if err := ctx.Err(); err != nil {
return nil, types.NodeInfo{}, nil, err
}
peerInfo, err := types.NodeInfoFromProto(&pbPeerInfo)
if err != nil {
return nil, types.NodeInfo{}, nil, err
}
mconn := conn.NewMConnection(
c.logger.With("peer", c.RemoteEndpoint().NodeAddress(peerInfo.NodeID)),
secretConn,
c.channelDescs,
c.onReceive,
c.onError,
c.mConnConfig,
)
return mconn, peerInfo, secretConn.RemotePubKey(), nil
}
// onReceive is a callback for MConnection received messages.
func (c *mConnConnection) onReceive(ctx context.Context, chID ChannelID, payload []byte) {
select {
case c.receiveCh <- mConnMessage{channelID: chID, payload: payload}:
case <-ctx.Done():
}
}
// onError is a callback for MConnection errors. The error is passed via errorCh
// to ReceiveMessage (but not SendMessage, for legacy P2P stack behavior).
func (c *mConnConnection) onError(ctx context.Context, e interface{}) {
err, ok := e.(error)
if !ok {
err = fmt.Errorf("%v", err)
}
// We have to close the connection here, since MConnection will have stopped
// the service on any errors.
_ = c.Close()
select {
case c.errorCh <- err:
case <-ctx.Done():
}
}
// String displays connection information.
func (c *mConnConnection) String() string {
return c.RemoteEndpoint().String()
}
// SendMessage implements Connection.
func (c *mConnConnection) SendMessage(ctx context.Context, chID ChannelID, msg []byte) error {
if chID > math.MaxUint8 {
return fmt.Errorf("MConnection only supports 1-byte channel IDs (got %v)", chID)
}
select {
case err := <-c.errorCh:
return err
case <-ctx.Done():
return io.EOF
default:
if ok := c.mconn.Send(chID, msg); !ok {
return errors.New("sending message timed out")
}
return nil
}
}
// ReceiveMessage implements Connection.
func (c *mConnConnection) ReceiveMessage(ctx context.Context) (ChannelID, []byte, error) {
select {
case err := <-c.errorCh:
return 0, nil, err
case <-c.doneCh:
return 0, nil, io.EOF
case <-ctx.Done():
return 0, nil, io.EOF
case msg := <-c.receiveCh:
return msg.channelID, msg.payload, nil
}
}
// LocalEndpoint implements Connection.
func (c *mConnConnection) LocalEndpoint() Endpoint {
endpoint := Endpoint{
Protocol: MConnProtocol,
}
if addr, ok := c.conn.LocalAddr().(*net.TCPAddr); ok {
endpoint.IP = addr.IP
endpoint.Port = uint16(addr.Port)
}
return endpoint
}
// RemoteEndpoint implements Connection.
func (c *mConnConnection) RemoteEndpoint() Endpoint {
endpoint := Endpoint{
Protocol: MConnProtocol,
}
if addr, ok := c.conn.RemoteAddr().(*net.TCPAddr); ok {
endpoint.IP = addr.IP
endpoint.Port = uint16(addr.Port)
}
return endpoint
}
// Close implements Connection.
func (c *mConnConnection) Close() error {
var err error
c.closeOnce.Do(func() {
defer close(c.doneCh)
if c.mconn != nil && c.mconn.IsRunning() {
c.mconn.Stop()
} else {
err = c.conn.Close()
}
})
return err
}