Timemachine/mc-router
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Add connection webhook notifications (#392)

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Also 

* Added decode of LoginStart message
* Add metrics backend constants
* Updated usage section
* Documented MaxFrameLength
This commit is contained in:
Geoff Bourne
2025-04-21 20:28:34 -05:00
committed by GitHub
parent a058d6e21d
commit cc590524c4
13 changed files with 585 additions and 66 deletions
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server/connector.go
+102 -15
View File
@@ -1,8 +1,11 @@
package server
import (
"bufio"
"bytes"
"context"
"fmt"
"github.com/google/uuid"
"io"
"net"
"sync"
@@ -33,15 +36,34 @@ type ConnectorMetrics struct {
ActiveConnections metrics.Gauge
}
func NewConnector(metrics *ConnectorMetrics, sendProxyProto bool, receiveProxyProto bool, trustedProxyNets []*net.IPNet,
clientFilter *ClientFilter) *Connector {
type ClientInfo struct {
Host string `json:"host"`
Port int `json:"port"`
}
func ClientInfoFromAddr(addr net.Addr) *ClientInfo {
if addr == nil {
return nil
}
return &ClientInfo{
Host: addr.(*net.TCPAddr).IP.String(),
Port: addr.(*net.TCPAddr).Port,
}
}
type PlayerInfo struct {
Name string `json:"name"`
Uuid uuid.UUID `json:"uuid"`
}
func NewConnector(metrics *ConnectorMetrics, sendProxyProto bool, receiveProxyProto bool, trustedProxyNets []*net.IPNet) *Connector {
return &Connector{
metrics: metrics,
sendProxyProto: sendProxyProto,
connectionsCond: sync.NewCond(&sync.Mutex{}),
receiveProxyProto: receiveProxyProto,
trustedProxyNets: trustedProxyNets,
clientFilter: clientFilter,
}
}
@@ -56,6 +78,16 @@ type Connector struct {
connectionsCond *sync.Cond
ngrokToken string
clientFilter *ClientFilter
connectionNotifier ConnectionNotifier
}
func (c *Connector) SetConnectionNotifier(notifier ConnectionNotifier) {
c.connectionNotifier = notifier
}
func (c *Connector) SetClientFilter(filter *ClientFilter) {
c.clientFilter = filter
}
func (c *Connector) StartAcceptingConnections(ctx context.Context, listenAddress string, connRateLimit int) error {
@@ -169,10 +201,12 @@ func (c *Connector) HandleConnection(ctx context.Context, frontendConn net.Conn)
clientAddr := frontendConn.RemoteAddr()
if tcpAddr, ok := clientAddr.(*net.TCPAddr); ok {
allow := c.clientFilter.Allow(tcpAddr.AddrPort())
if !allow {
logrus.WithField("client", clientAddr).Debug("Client is blocked")
return
if c.clientFilter != nil {
allow := c.clientFilter.Allow(tcpAddr.AddrPort())
if !allow {
logrus.WithField("client", clientAddr).Debug("Client is blocked")
return
}
}
} else {
logrus.WithField("client", clientAddr).Warn("Remote address is not a TCP address, skipping filtering")
@@ -183,10 +217,12 @@ func (c *Connector) HandleConnection(ctx context.Context, frontendConn net.Conn)
Info("Got connection")
defer logrus.WithField("client", clientAddr).Debug("Closing frontend connection")
// Tee-off the inspected content to a buffer so that we can retransmit it to the backend connection
inspectionBuffer := new(bytes.Buffer)
inspectionReader := io.TeeReader(frontendConn, inspectionBuffer)
bufferedReader := bufio.NewReader(inspectionReader)
if err := frontendConn.SetReadDeadline(time.Now().Add(handshakeTimeout)); err != nil {
logrus.
WithError(err).
@@ -195,7 +231,7 @@ func (c *Connector) HandleConnection(ctx context.Context, frontendConn net.Conn)
c.metrics.Errors.With("type", "read_deadline").Add(1)
return
}
packet, err := mcproto.ReadPacket(inspectionReader, clientAddr, c.state)
packet, err := mcproto.ReadPacket(bufferedReader, clientAddr, c.state)
if err != nil {
logrus.WithError(err).WithField("clientAddr", clientAddr).Error("Failed to read packet")
c.metrics.Errors.With("type", "read").Add(1)
@@ -209,7 +245,7 @@ func (c *Connector) HandleConnection(ctx context.Context, frontendConn net.Conn)
Debug("Got packet")
if packet.PacketID == mcproto.PacketIdHandshake {
handshake, err := mcproto.ReadHandshake(packet.Data)
handshake, err := mcproto.DecodeHandshake(packet.Data)
if err != nil {
logrus.WithError(err).WithField("clientAddr", clientAddr).
Error("Failed to read handshake")
@@ -222,10 +258,25 @@ func (c *Connector) HandleConnection(ctx context.Context, frontendConn net.Conn)
WithField("handshake", handshake).
Debug("Got handshake")
serverAddress := handshake.ServerAddress
nextState := mcproto.State(handshake.NextState)
var userInfo *PlayerInfo = nil
if handshake.NextState == mcproto.StateLogin {
userInfo, err = c.readUserInfo(bufferedReader, clientAddr, handshake.NextState)
if err != nil {
logrus.
WithError(err).
WithField("clientAddr", clientAddr).
Error("Failed to read user info")
c.metrics.Errors.With("type", "read").Add(1)
return
}
logrus.
WithField("client", clientAddr).
WithField("userInfo", userInfo).
Debug("Got user info")
}
c.findAndConnectBackend(ctx, frontendConn, clientAddr, inspectionBuffer, handshake.ServerAddress, userInfo, handshake.NextState)
c.findAndConnectBackend(ctx, frontendConn, clientAddr, inspectionBuffer, serverAddress, nextState)
} else if packet.PacketID == mcproto.PacketIdLegacyServerListPing {
handshake, ok := packet.Data.(*mcproto.LegacyServerListPing)
if !ok {
@@ -244,7 +295,7 @@ func (c *Connector) HandleConnection(ctx context.Context, frontendConn net.Conn)
serverAddress := handshake.ServerAddress
c.findAndConnectBackend(ctx, frontendConn, clientAddr, inspectionBuffer, serverAddress, mcproto.StateStatus)
c.findAndConnectBackend(ctx, frontendConn, clientAddr, inspectionBuffer, serverAddress, nil, mcproto.StateStatus)
} else {
logrus.
WithField("client", clientAddr).
@@ -255,8 +306,28 @@ func (c *Connector) HandleConnection(ctx context.Context, frontendConn net.Conn)
}
}
func (c *Connector) readUserInfo(bufferedReader *bufio.Reader, clientAddr net.Addr, state mcproto.State) (*PlayerInfo, error) {
loginPacket, err := mcproto.ReadPacket(bufferedReader, clientAddr, state)
if err != nil {
return nil, fmt.Errorf("failed to read login packet: %w", err)
}
if loginPacket.PacketID == mcproto.PacketIdLogin {
loginStart, err := mcproto.DecodeLoginStart(loginPacket.Data)
if err != nil {
return nil, fmt.Errorf("failed to decode login start: %w", err)
}
return &PlayerInfo{
Name: loginStart.Name,
Uuid: loginStart.PlayerUuid,
}, nil
} else {
return nil, fmt.Errorf("expected login packet, got %d", loginPacket.PacketID)
}
}
func (c *Connector) findAndConnectBackend(ctx context.Context, frontendConn net.Conn,
clientAddr net.Addr, preReadContent io.Reader, serverAddress string, nextState mcproto.State) {
clientAddr net.Addr, preReadContent io.Reader, serverAddress string, userInfo *PlayerInfo, nextState mcproto.State) {
backendHostPort, resolvedHost, waker := Routes.FindBackendForServerAddress(ctx, serverAddress)
if waker != nil && nextState > mcproto.StateStatus {
@@ -273,13 +344,20 @@ func (c *Connector) findAndConnectBackend(ctx context.Context, frontendConn net.
WithField("resolvedHost", resolvedHost).
Warn("Unable to find registered backend")
c.metrics.Errors.With("type", "missing_backend").Add(1)
if c.connectionNotifier != nil {
c.connectionNotifier.NotifyMissingBackend(ctx, clientAddr, serverAddress, userInfo)
}
return
}
logrus.
WithField("client", clientAddr).
WithField("server", serverAddress).
WithField("backendHostPort", backendHostPort).
Info("Connecting to backend")
backendConn, err := net.Dial("tcp", backendHostPort)
if err != nil {
logrus.
@@ -289,9 +367,18 @@ func (c *Connector) findAndConnectBackend(ctx context.Context, frontendConn net.
WithField("backend", backendHostPort).
Warn("Unable to connect to backend")
c.metrics.Errors.With("type", "backend_failed").Add(1)
if c.connectionNotifier != nil {
c.connectionNotifier.NotifyFailedBackendConnection(ctx, clientAddr, serverAddress, userInfo, backendHostPort, err)
}
return
}
if c.connectionNotifier != nil {
c.connectionNotifier.NotifyConnected(ctx, clientAddr, serverAddress, userInfo, backendHostPort)
}
c.metrics.ConnectionsBackend.With("host", resolvedHost).Add(1)
c.metrics.ActiveConnections.Set(float64(