| /* |
| 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" |
| |
| "k8s.io/api/core/v1" |
| "k8s.io/apimachinery/pkg/util/runtime" |
| "k8s.io/klog" |
| "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 v1.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 |
| case "SCTP": |
| return nil, fmt.Errorf("SCTP is not supported for user space proxy") |
| } |
| 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 successfully 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 { |
| klog.Errorf("Couldn't find an endpoint for %s: %v", service, err) |
| return nil, err |
| } |
| klog.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()) |
| } |
| klog.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 |
| } |
| klog.Errorf("Accept failed: %v", err) |
| continue |
| } |
| klog.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 { |
| klog.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) |
| klog.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() |
| klog.V(4).Infof("Copying %s: %s -> %s", direction, src.RemoteAddr(), dest.RemoteAddr()) |
| n, err := io.Copy(dest, src) |
| if err != nil { |
| if !isClosedError(err) { |
| klog.Errorf("I/O error: %v", err) |
| } |
| } |
| klog.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() { |
| klog.V(1).Infof("ReadFrom had a temporary failure: %v", err) |
| continue |
| } |
| } |
| klog.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) { |
| klog.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 { |
| klog.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. |
| klog.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 { |
| klog.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) { |
| klog.Errorf("Read failed: %v", err) |
| } |
| break |
| } |
| err = svrConn.SetDeadline(time.Now().Add(timeout)) |
| if err != nil { |
| klog.Errorf("SetDeadline failed: %v", err) |
| break |
| } |
| n, err = udp.WriteTo(buffer[0:n], cliAddr) |
| if err != nil { |
| if !logTimeout(err) { |
| klog.Errorf("WriteTo failed: %v", err) |
| } |
| break |
| } |
| } |
| activeClients.Mu.Lock() |
| delete(activeClients.Clients, cliAddr.String()) |
| activeClients.Mu.Unlock() |
| } |