Fix concurrency on the client (#183)

* reworked peer connection establishment logic eliminating race conditions and deadlocks while running many peers

client/internal/proxy/dummy.go

@@ -0,0 +1,68 @@
+package proxy
+
+import (
+	"context"
+	log "github.com/sirupsen/logrus"
+	"net"
+	"time"
+)
+
+// DummyProxy just sends pings to the RemoteKey peer and reads responses
+type DummyProxy struct {
+	conn   net.Conn
+	remote string
+	ctx    context.Context
+	cancel context.CancelFunc
+}
+
+func NewDummyProxy(remote string) *DummyProxy {
+	p := &DummyProxy{remote: remote}
+	p.ctx, p.cancel = context.WithCancel(context.Background())
+	return p
+}
+
+func (p *DummyProxy) Close() error {
+	p.cancel()
+	return nil
+}
+
+func (p *DummyProxy) Start(remoteConn net.Conn) error {
+	p.conn = remoteConn
+	go func() {
+		buf := make([]byte, 1500)
+		for {
+			select {
+			case <-p.ctx.Done():
+				return
+			default:
+				_, err := p.conn.Read(buf)
+				if err != nil {
+					log.Errorf("error while reading RemoteKey %s proxy %v", p.remote, err)
+					return
+				}
+				//log.Debugf("received %s from %s", string(buf[:n]), p.remote)
+			}
+
+		}
+	}()
+
+	go func() {
+		for {
+			select {
+			case <-p.ctx.Done():
+				return
+			default:
+				_, err := p.conn.Write([]byte("hello"))
+				//log.Debugf("sent ping to %s", p.remote)
+				if err != nil {
+					log.Errorf("error while writing to RemoteKey %s proxy %v", p.remote, err)
+					return
+				}
+				time.Sleep(5 * time.Second)
+			}
+		}
+
+	}()
+
+	return nil
+}

client/internal/proxy/proxy.go

@@ -0,0 +1,24 @@
+package proxy
+
+import (
+	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
+	"io"
+	"net"
+	"time"
+)
+
+const DefaultWgKeepAlive = 25 * time.Second
+
+type Config struct {
+	WgListenAddr string
+	RemoteKey    string
+	WgInterface  string
+	AllowedIps   string
+	PreSharedKey *wgtypes.Key
+}
+
+type Proxy interface {
+	io.Closer
+	// Start creates a local remoteConn and starts proxying data from/to remoteConn
+	Start(remoteConn net.Conn) error
+}

client/internal/proxy/wireguard.go

@@ -0,0 +1,121 @@
+package proxy
+
+import (
+	"context"
+	log "github.com/sirupsen/logrus"
+	"github.com/wiretrustee/wiretrustee/iface"
+	"net"
+)
+
+// WireguardProxy proxies
+type WireguardProxy struct {
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	config Config
+
+	remoteConn net.Conn
+	localConn  net.Conn
+}
+
+func NewWireguardProxy(config Config) *WireguardProxy {
+	p := &WireguardProxy{config: config}
+	p.ctx, p.cancel = context.WithCancel(context.Background())
+	return p
+}
+
+func (p *WireguardProxy) updateEndpoint() error {
+	// add local proxy connection as a Wireguard peer
+	err := iface.UpdatePeer(p.config.WgInterface, p.config.RemoteKey, p.config.AllowedIps, DefaultWgKeepAlive,
+		p.localConn.LocalAddr().String(), p.config.PreSharedKey)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (p *WireguardProxy) Start(remoteConn net.Conn) error {
+	p.remoteConn = remoteConn
+
+	var err error
+	p.localConn, err = net.Dial("udp", p.config.WgListenAddr)
+	if err != nil {
+		log.Errorf("failed dialing to local Wireguard port %s", err)
+		return err
+	}
+
+	err = p.updateEndpoint()
+	if err != nil {
+		log.Errorf("error while updating Wireguard peer endpoint [%s] %v", p.config.RemoteKey, err)
+		return err
+	}
+
+	go p.proxyToRemote()
+	go p.proxyToLocal()
+
+	return nil
+}
+
+func (p *WireguardProxy) Close() error {
+	p.cancel()
+	if c := p.localConn; c != nil {
+		err := p.localConn.Close()
+		if err != nil {
+			return err
+		}
+	}
+	err := iface.RemovePeer(p.config.WgInterface, p.config.RemoteKey)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// proxyToRemote proxies everything from Wireguard to the RemoteKey peer
+// blocks
+func (p *WireguardProxy) proxyToRemote() {
+
+	buf := make([]byte, 1500)
+	for {
+		select {
+		case <-p.ctx.Done():
+			log.Debugf("stopped proxying to remote peer %s due to closed connection", p.config.RemoteKey)
+			return
+		default:
+			n, err := p.localConn.Read(buf)
+			if err != nil {
+				continue
+			}
+
+			_, err = p.remoteConn.Write(buf[:n])
+			if err != nil {
+				continue
+			}
+		}
+	}
+}
+
+// proxyToLocal proxies everything from the RemoteKey peer to local Wireguard
+// blocks
+func (p *WireguardProxy) proxyToLocal() {
+
+	buf := make([]byte, 1500)
+	for {
+		select {
+		case <-p.ctx.Done():
+			log.Debugf("stopped proxying from remote peer %s due to closed connection", p.config.RemoteKey)
+			return
+		default:
+			n, err := p.remoteConn.Read(buf)
+			if err != nil {
+				continue
+			}
+
+			_, err = p.localConn.Write(buf[:n])
+			if err != nil {
+				continue
+			}
+		}
+	}
+}