vendor files

vendor/k8s.io/kubernetes/pkg/proxy/userspace/proxysocket.go

@@ -0,0 +1,302 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+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 userspace
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/golang/glog"
+	"k8s.io/apimachinery/pkg/util/runtime"
+	api "k8s.io/kubernetes/pkg/apis/core"
+	"k8s.io/kubernetes/pkg/proxy"
+)
+
+// Abstraction over TCP/UDP sockets which are proxied.
+type ProxySocket interface {
+	// Addr gets the net.Addr for a ProxySocket.
+	Addr() net.Addr
+	// Close stops the ProxySocket from accepting incoming connections.
+	// Each implementation should comment on the impact of calling Close
+	// while sessions are active.
+	Close() error
+	// ProxyLoop proxies incoming connections for the specified service to the service endpoints.
+	ProxyLoop(service proxy.ServicePortName, info *ServiceInfo, loadBalancer LoadBalancer)
+	// ListenPort returns the host port that the ProxySocket is listening on
+	ListenPort() int
+}
+
+func newProxySocket(protocol api.Protocol, ip net.IP, port int) (ProxySocket, error) {
+	host := ""
+	if ip != nil {
+		host = ip.String()
+	}
+
+	switch strings.ToUpper(string(protocol)) {
+	case "TCP":
+		listener, err := net.Listen("tcp", net.JoinHostPort(host, strconv.Itoa(port)))
+		if err != nil {
+			return nil, err
+		}
+		return &tcpProxySocket{Listener: listener, port: port}, nil
+	case "UDP":
+		addr, err := net.ResolveUDPAddr("udp", net.JoinHostPort(host, strconv.Itoa(port)))
+		if err != nil {
+			return nil, err
+		}
+		conn, err := net.ListenUDP("udp", addr)
+		if err != nil {
+			return nil, err
+		}
+		return &udpProxySocket{UDPConn: conn, port: port}, nil
+	}
+	return nil, fmt.Errorf("unknown protocol %q", protocol)
+}
+
+// How long we wait for a connection to a backend in seconds
+var EndpointDialTimeouts = []time.Duration{250 * time.Millisecond, 500 * time.Millisecond, 1 * time.Second, 2 * time.Second}
+
+// tcpProxySocket implements ProxySocket.  Close() is implemented by net.Listener.  When Close() is called,
+// no new connections are allowed but existing connections are left untouched.
+type tcpProxySocket struct {
+	net.Listener
+	port int
+}
+
+func (tcp *tcpProxySocket) ListenPort() int {
+	return tcp.port
+}
+
+// TryConnectEndpoints attempts to connect to the next available endpoint for the given service, cycling
+// through until it is able to successully connect, or it has tried with all timeouts in EndpointDialTimeouts.
+func TryConnectEndpoints(service proxy.ServicePortName, srcAddr net.Addr, protocol string, loadBalancer LoadBalancer) (out net.Conn, err error) {
+	sessionAffinityReset := false
+	for _, dialTimeout := range EndpointDialTimeouts {
+		endpoint, err := loadBalancer.NextEndpoint(service, srcAddr, sessionAffinityReset)
+		if err != nil {
+			glog.Errorf("Couldn't find an endpoint for %s: %v", service, err)
+			return nil, err
+		}
+		glog.V(3).Infof("Mapped service %q to endpoint %s", service, endpoint)
+		// TODO: This could spin up a new goroutine to make the outbound connection,
+		// and keep accepting inbound traffic.
+		outConn, err := net.DialTimeout(protocol, endpoint, dialTimeout)
+		if err != nil {
+			if isTooManyFDsError(err) {
+				panic("Dial failed: " + err.Error())
+			}
+			glog.Errorf("Dial failed: %v", err)
+			sessionAffinityReset = true
+			continue
+		}
+		return outConn, nil
+	}
+	return nil, fmt.Errorf("failed to connect to an endpoint.")
+}
+
+func (tcp *tcpProxySocket) ProxyLoop(service proxy.ServicePortName, myInfo *ServiceInfo, loadBalancer LoadBalancer) {
+	for {
+		if !myInfo.IsAlive() {
+			// The service port was closed or replaced.
+			return
+		}
+		// Block until a connection is made.
+		inConn, err := tcp.Accept()
+		if err != nil {
+			if isTooManyFDsError(err) {
+				panic("Accept failed: " + err.Error())
+			}
+
+			if isClosedError(err) {
+				return
+			}
+			if !myInfo.IsAlive() {
+				// Then the service port was just closed so the accept failure is to be expected.
+				return
+			}
+			glog.Errorf("Accept failed: %v", err)
+			continue
+		}
+		glog.V(3).Infof("Accepted TCP connection from %v to %v", inConn.RemoteAddr(), inConn.LocalAddr())
+		outConn, err := TryConnectEndpoints(service, inConn.(*net.TCPConn).RemoteAddr(), "tcp", loadBalancer)
+		if err != nil {
+			glog.Errorf("Failed to connect to balancer: %v", err)
+			inConn.Close()
+			continue
+		}
+		// Spin up an async copy loop.
+		go ProxyTCP(inConn.(*net.TCPConn), outConn.(*net.TCPConn))
+	}
+}
+
+// ProxyTCP proxies data bi-directionally between in and out.
+func ProxyTCP(in, out *net.TCPConn) {
+	var wg sync.WaitGroup
+	wg.Add(2)
+	glog.V(4).Infof("Creating proxy between %v <-> %v <-> %v <-> %v",
+		in.RemoteAddr(), in.LocalAddr(), out.LocalAddr(), out.RemoteAddr())
+	go copyBytes("from backend", in, out, &wg)
+	go copyBytes("to backend", out, in, &wg)
+	wg.Wait()
+}
+
+func copyBytes(direction string, dest, src *net.TCPConn, wg *sync.WaitGroup) {
+	defer wg.Done()
+	glog.V(4).Infof("Copying %s: %s -> %s", direction, src.RemoteAddr(), dest.RemoteAddr())
+	n, err := io.Copy(dest, src)
+	if err != nil {
+		if !isClosedError(err) {
+			glog.Errorf("I/O error: %v", err)
+		}
+	}
+	glog.V(4).Infof("Copied %d bytes %s: %s -> %s", n, direction, src.RemoteAddr(), dest.RemoteAddr())
+	dest.Close()
+	src.Close()
+}
+
+// udpProxySocket implements ProxySocket.  Close() is implemented by net.UDPConn.  When Close() is called,
+// no new connections are allowed and existing connections are broken.
+// TODO: We could lame-duck this ourselves, if it becomes important.
+type udpProxySocket struct {
+	*net.UDPConn
+	port int
+}
+
+func (udp *udpProxySocket) ListenPort() int {
+	return udp.port
+}
+
+func (udp *udpProxySocket) Addr() net.Addr {
+	return udp.LocalAddr()
+}
+
+// Holds all the known UDP clients that have not timed out.
+type ClientCache struct {
+	Mu      sync.Mutex
+	Clients map[string]net.Conn // addr string -> connection
+}
+
+func newClientCache() *ClientCache {
+	return &ClientCache{Clients: map[string]net.Conn{}}
+}
+
+func (udp *udpProxySocket) ProxyLoop(service proxy.ServicePortName, myInfo *ServiceInfo, loadBalancer LoadBalancer) {
+	var buffer [4096]byte // 4KiB should be enough for most whole-packets
+	for {
+		if !myInfo.IsAlive() {
+			// The service port was closed or replaced.
+			break
+		}
+
+		// Block until data arrives.
+		// TODO: Accumulate a histogram of n or something, to fine tune the buffer size.
+		n, cliAddr, err := udp.ReadFrom(buffer[0:])
+		if err != nil {
+			if e, ok := err.(net.Error); ok {
+				if e.Temporary() {
+					glog.V(1).Infof("ReadFrom had a temporary failure: %v", err)
+					continue
+				}
+			}
+			glog.Errorf("ReadFrom failed, exiting ProxyLoop: %v", err)
+			break
+		}
+		// If this is a client we know already, reuse the connection and goroutine.
+		svrConn, err := udp.getBackendConn(myInfo.ActiveClients, cliAddr, loadBalancer, service, myInfo.Timeout)
+		if err != nil {
+			continue
+		}
+		// TODO: It would be nice to let the goroutine handle this write, but we don't
+		// really want to copy the buffer.  We could do a pool of buffers or something.
+		_, err = svrConn.Write(buffer[0:n])
+		if err != nil {
+			if !logTimeout(err) {
+				glog.Errorf("Write failed: %v", err)
+				// TODO: Maybe tear down the goroutine for this client/server pair?
+			}
+			continue
+		}
+		err = svrConn.SetDeadline(time.Now().Add(myInfo.Timeout))
+		if err != nil {
+			glog.Errorf("SetDeadline failed: %v", err)
+			continue
+		}
+	}
+}
+
+func (udp *udpProxySocket) getBackendConn(activeClients *ClientCache, cliAddr net.Addr, loadBalancer LoadBalancer, service proxy.ServicePortName, timeout time.Duration) (net.Conn, error) {
+	activeClients.Mu.Lock()
+	defer activeClients.Mu.Unlock()
+
+	svrConn, found := activeClients.Clients[cliAddr.String()]
+	if !found {
+		// TODO: This could spin up a new goroutine to make the outbound connection,
+		// and keep accepting inbound traffic.
+		glog.V(3).Infof("New UDP connection from %s", cliAddr)
+		var err error
+		svrConn, err = TryConnectEndpoints(service, cliAddr, "udp", loadBalancer)
+		if err != nil {
+			return nil, err
+		}
+		if err = svrConn.SetDeadline(time.Now().Add(timeout)); err != nil {
+			glog.Errorf("SetDeadline failed: %v", err)
+			return nil, err
+		}
+		activeClients.Clients[cliAddr.String()] = svrConn
+		go func(cliAddr net.Addr, svrConn net.Conn, activeClients *ClientCache, timeout time.Duration) {
+			defer runtime.HandleCrash()
+			udp.proxyClient(cliAddr, svrConn, activeClients, timeout)
+		}(cliAddr, svrConn, activeClients, timeout)
+	}
+	return svrConn, nil
+}
+
+// This function is expected to be called as a goroutine.
+// TODO: Track and log bytes copied, like TCP
+func (udp *udpProxySocket) proxyClient(cliAddr net.Addr, svrConn net.Conn, activeClients *ClientCache, timeout time.Duration) {
+	defer svrConn.Close()
+	var buffer [4096]byte
+	for {
+		n, err := svrConn.Read(buffer[0:])
+		if err != nil {
+			if !logTimeout(err) {
+				glog.Errorf("Read failed: %v", err)
+			}
+			break
+		}
+		err = svrConn.SetDeadline(time.Now().Add(timeout))
+		if err != nil {
+			glog.Errorf("SetDeadline failed: %v", err)
+			break
+		}
+		n, err = udp.WriteTo(buffer[0:n], cliAddr)
+		if err != nil {
+			if !logTimeout(err) {
+				glog.Errorf("WriteTo failed: %v", err)
+			}
+			break
+		}
+	}
+	activeClients.Mu.Lock()
+	delete(activeClients.Clients, cliAddr.String())
+	activeClients.Mu.Unlock()
+}