// +build linux package libpod import ( "crypto/rand" "fmt" "net" "os" "os/exec" "path/filepath" "strconv" "strings" "syscall" "time" cnitypes "github.com/containernetworking/cni/pkg/types/current" "github.com/containernetworking/plugins/pkg/ns" "github.com/containers/libpod/pkg/firewall" "github.com/containers/libpod/pkg/netns" "github.com/containers/libpod/pkg/rootless" "github.com/cri-o/ocicni/pkg/ocicni" "github.com/pkg/errors" "github.com/sirupsen/logrus" "github.com/vishvananda/netlink" "golang.org/x/sys/unix" ) // Get an OCICNI network config func (r *Runtime) getPodNetwork(id, name, nsPath string, networks []string, ports []ocicni.PortMapping, staticIP net.IP) ocicni.PodNetwork { network := ocicni.PodNetwork{ Name: name, Namespace: name, // TODO is there something else we should put here? We don't know about Kube namespaces ID: id, NetNS: nsPath, PortMappings: ports, Networks: networks, } if staticIP != nil { defaultNetwork := r.netPlugin.GetDefaultNetworkName() network.Networks = []string{defaultNetwork} network.NetworkConfig = make(map[string]ocicni.NetworkConfig) network.NetworkConfig[defaultNetwork] = ocicni.NetworkConfig{IP: staticIP.String()} } return network } // Create and configure a new network namespace for a container func (r *Runtime) configureNetNS(ctr *Container, ctrNS ns.NetNS) ([]*cnitypes.Result, error) { var requestedIP net.IP if ctr.requestedIP != nil { requestedIP = ctr.requestedIP // cancel request for a specific IP in case the container is reused later ctr.requestedIP = nil } else { requestedIP = ctr.config.StaticIP } podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctrNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP) results, err := r.netPlugin.SetUpPod(podNetwork) if err != nil { return nil, errors.Wrapf(err, "error configuring network namespace for container %s", ctr.ID()) } defer func() { if err != nil { if err2 := r.netPlugin.TearDownPod(podNetwork); err2 != nil { logrus.Errorf("Error tearing down partially created network namespace for container %s: %v", ctr.ID(), err2) } } }() networkStatus := make([]*cnitypes.Result, 0) for idx, r := range results { logrus.Debugf("[%d] CNI result: %v", idx, r.String()) resultCurrent, err := cnitypes.GetResult(r) if err != nil { return nil, errors.Wrapf(err, "error parsing CNI plugin result %q: %v", r.String(), err) } networkStatus = append(networkStatus, resultCurrent) } // Add firewall rules to ensure the container has network access. // Will not be necessary once CNI firewall plugin merges upstream. // https://github.com/containernetworking/plugins/pull/75 for _, netStatus := range networkStatus { firewallConf := &firewall.FirewallNetConf{ PrevResult: netStatus, } if err := r.firewallBackend.Add(firewallConf); err != nil { return nil, errors.Wrapf(err, "error adding firewall rules for container %s", ctr.ID()) } } return networkStatus, nil } // Create and configure a new network namespace for a container func (r *Runtime) createNetNS(ctr *Container) (n ns.NetNS, q []*cnitypes.Result, err error) { if rootless.IsRootless() { return nil, nil, errors.New("cannot configure a new network namespace in rootless mode, only --network=slirp4netns is supported") } ctrNS, err := netns.NewNS() if err != nil { return nil, nil, errors.Wrapf(err, "error creating network namespace for container %s", ctr.ID()) } defer func() { if err != nil { if err2 := netns.UnmountNS(ctrNS); err2 != nil { logrus.Errorf("Error unmounting partially created network namespace for container %s: %v", ctr.ID(), err2) } if err2 := ctrNS.Close(); err2 != nil { logrus.Errorf("Error closing partially created network namespace for container %s: %v", ctr.ID(), err2) } } }() logrus.Debugf("Made network namespace at %s for container %s", ctrNS.Path(), ctr.ID()) networkStatus, err := r.configureNetNS(ctr, ctrNS) return ctrNS, networkStatus, err } type slirp4netnsCmdArg struct { Proto string `json:"proto,omitempty"` HostAddr string `json:"host_addr"` HostPort int32 `json:"host_port"` GuestAddr string `json:"guest_addr"` GuestPort int32 `json:"guest_port"` } type slirp4netnsCmd struct { Execute string `json:"execute"` Args slirp4netnsCmdArg `json:"arguments"` } func checkSlirpFlags(path string) (bool, bool, error) { cmd := exec.Command(path, "--help") out, err := cmd.CombinedOutput() if err != nil { return false, false, err } return strings.Contains(string(out), "--disable-host-loopback"), strings.Contains(string(out), "--mtu"), nil } // Configure the network namespace for a rootless container func (r *Runtime) setupRootlessNetNS(ctr *Container) (err error) { defer ctr.rootlessSlirpSyncR.Close() defer ctr.rootlessSlirpSyncW.Close() path := r.config.NetworkCmdPath if path == "" { var err error path, err = exec.LookPath("slirp4netns") if err != nil { logrus.Errorf("could not find slirp4netns, the network namespace won't be configured: %v", err) return nil } } syncR, syncW, err := os.Pipe() if err != nil { return errors.Wrapf(err, "failed to open pipe") } defer syncR.Close() defer syncW.Close() havePortMapping := len(ctr.Config().PortMappings) > 0 apiSocket := filepath.Join(r.ociRuntime.tmpDir, fmt.Sprintf("%s.net", ctr.config.ID)) cmdArgs := []string{} if havePortMapping { cmdArgs = append(cmdArgs, "--api-socket", apiSocket, fmt.Sprintf("%d", ctr.state.PID)) } dhp, mtu, err := checkSlirpFlags(path) if err != nil { return errors.Wrapf(err, "error checking slirp4netns binary %s", path) } if dhp { cmdArgs = append(cmdArgs, "--disable-host-loopback") } if mtu { cmdArgs = append(cmdArgs, "--mtu", "65520") } cmdArgs = append(cmdArgs, "-c", "-e", "3", "-r", "4", fmt.Sprintf("%d", ctr.state.PID), "tap0") cmd := exec.Command(path, cmdArgs...) cmd.SysProcAttr = &syscall.SysProcAttr{ Setpgid: true, } cmd.ExtraFiles = append(cmd.ExtraFiles, ctr.rootlessSlirpSyncR, syncW) if err := cmd.Start(); err != nil { return errors.Wrapf(err, "failed to start slirp4netns process") } defer cmd.Process.Release() b := make([]byte, 16) for { if err := syncR.SetDeadline(time.Now().Add(1 * time.Second)); err != nil { return errors.Wrapf(err, "error setting slirp4netns pipe timeout") } if _, err := syncR.Read(b); err == nil { break } else { if os.IsTimeout(err) { // Check if the process is still running. var status syscall.WaitStatus pid, err := syscall.Wait4(cmd.Process.Pid, &status, syscall.WNOHANG, nil) if err != nil { return errors.Wrapf(err, "failed to read slirp4netns process status") } if pid != cmd.Process.Pid { continue } if status.Exited() { return errors.New("slirp4netns failed") } if status.Signaled() { return errors.New("slirp4netns killed by signal") } continue } return errors.Wrapf(err, "failed to read from slirp4netns sync pipe") } } if havePortMapping { const pidWaitTimeout = 60 * time.Second chWait := make(chan error) go func() { interval := 25 * time.Millisecond for i := time.Duration(0); i < pidWaitTimeout; i += interval { // Check if the process is still running. var status syscall.WaitStatus pid, err := syscall.Wait4(cmd.Process.Pid, &status, syscall.WNOHANG, nil) if err != nil { break } if pid != cmd.Process.Pid { continue } if status.Exited() || status.Signaled() { chWait <- fmt.Errorf("slirp4netns exited with status %d", status.ExitStatus()) } time.Sleep(interval) } }() defer close(chWait) // wait that API socket file appears before trying to use it. if _, err := WaitForFile(apiSocket, chWait, pidWaitTimeout*time.Millisecond); err != nil { return errors.Wrapf(err, "waiting for slirp4nets to create the api socket file %s", apiSocket) } // for each port we want to add we need to open a connection to the slirp4netns control socket // and send the add_hostfwd command. for _, i := range ctr.config.PortMappings { conn, err := net.Dial("unix", apiSocket) if err != nil { return errors.Wrapf(err, "cannot open connection to %s", apiSocket) } defer conn.Close() hostIP := i.HostIP if hostIP == "" { hostIP = "0.0.0.0" } cmd := slirp4netnsCmd{ Execute: "add_hostfwd", Args: slirp4netnsCmdArg{ Proto: i.Protocol, HostAddr: hostIP, HostPort: i.HostPort, GuestPort: i.ContainerPort, }, } // create the JSON payload and send it. Mark the end of request shutting down writes // to the socket, as requested by slirp4netns. data, err := json.Marshal(&cmd) if err != nil { return errors.Wrapf(err, "cannot marshal JSON for slirp4netns") } if _, err := conn.Write([]byte(fmt.Sprintf("%s\n", data))); err != nil { return errors.Wrapf(err, "cannot write to control socket %s", apiSocket) } if err := conn.(*net.UnixConn).CloseWrite(); err != nil { return errors.Wrapf(err, "cannot shutdown the socket %s", apiSocket) } buf := make([]byte, 2048) len, err := conn.Read(buf) if err != nil { return errors.Wrapf(err, "cannot read from control socket %s", apiSocket) } // if there is no 'error' key in the received JSON data, then the operation was // successful. var y map[string]interface{} if err := json.Unmarshal(buf[0:len], &y); err != nil { return errors.Wrapf(err, "error parsing error status from slirp4netns") } if e, found := y["error"]; found { return errors.Errorf("error from slirp4netns while setting up port redirection: %v", e) } } } return nil } // Configure the network namespace using the container process func (r *Runtime) setupNetNS(ctr *Container) (err error) { nsProcess := fmt.Sprintf("/proc/%d/ns/net", ctr.state.PID) b := make([]byte, 16) if _, err := rand.Reader.Read(b); err != nil { return errors.Wrapf(err, "failed to generate random netns name") } nsPath := fmt.Sprintf("/var/run/netns/cni-%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:]) if err := os.MkdirAll(filepath.Dir(nsPath), 0711); err != nil { return errors.Wrapf(err, "cannot create %s", filepath.Dir(nsPath)) } mountPointFd, err := os.Create(nsPath) if err != nil { return errors.Wrapf(err, "cannot open %s", nsPath) } mountPointFd.Close() if err := unix.Mount(nsProcess, nsPath, "none", unix.MS_BIND, ""); err != nil { return errors.Wrapf(err, "cannot mount %s", nsPath) } netNS, err := ns.GetNS(nsPath) if err != nil { return err } networkStatus, err := r.configureNetNS(ctr, netNS) // Assign NetNS attributes to container ctr.state.NetNS = netNS ctr.state.NetworkStatus = networkStatus return err } // Join an existing network namespace func joinNetNS(path string) (ns.NetNS, error) { ns, err := ns.GetNS(path) if err != nil { return nil, errors.Wrapf(err, "error retrieving network namespace at %s", path) } return ns, nil } // Close a network namespace. // Differs from teardownNetNS() in that it will not attempt to undo the setup of // the namespace, but will instead only close the open file descriptor func (r *Runtime) closeNetNS(ctr *Container) error { if ctr.state.NetNS == nil { // The container has no network namespace, we're set return nil } if err := ctr.state.NetNS.Close(); err != nil { return errors.Wrapf(err, "error closing network namespace for container %s", ctr.ID()) } ctr.state.NetNS = nil return nil } // Tear down a network namespace, undoing all state associated with it. // The CNI firewall rules will be removed, the namespace will be unmounted, // and the file descriptor associated with it closed. func (r *Runtime) teardownNetNS(ctr *Container) error { if ctr.state.NetNS == nil { // The container has no network namespace, we're set return nil } // Remove firewall rules we added on configuring the container. // Will not be necessary once CNI firewall plugin merges upstream. // https://github.com/containernetworking/plugins/pull/75 for _, netStatus := range ctr.state.NetworkStatus { firewallConf := &firewall.FirewallNetConf{ PrevResult: netStatus, } if err := r.firewallBackend.Del(firewallConf); err != nil { return errors.Wrapf(err, "error removing firewall rules for container %s", ctr.ID()) } } logrus.Debugf("Tearing down network namespace at %s for container %s", ctr.state.NetNS.Path(), ctr.ID()) var requestedIP net.IP if ctr.requestedIP != nil { requestedIP = ctr.requestedIP // cancel request for a specific IP in case the container is reused later ctr.requestedIP = nil } else { requestedIP = ctr.config.StaticIP } podNetwork := r.getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.Networks, ctr.config.PortMappings, requestedIP) // The network may have already been torn down, so don't fail here, just log if err := r.netPlugin.TearDownPod(podNetwork); err != nil { return errors.Wrapf(err, "error tearing down CNI namespace configuration for container %s", ctr.ID()) } // First unmount the namespace if err := netns.UnmountNS(ctr.state.NetNS); err != nil { return errors.Wrapf(err, "error unmounting network namespace for container %s", ctr.ID()) } // Now close the open file descriptor if err := ctr.state.NetNS.Close(); err != nil { return errors.Wrapf(err, "error closing network namespace for container %s", ctr.ID()) } ctr.state.NetNS = nil return nil } func getContainerNetNS(ctr *Container) (string, error) { if ctr.state.NetNS != nil { return ctr.state.NetNS.Path(), nil } if ctr.config.NetNsCtr != "" { c, err := ctr.runtime.GetContainer(ctr.config.NetNsCtr) if err != nil { return "", err } if err = c.syncContainer(); err != nil { return "", err } return c.state.NetNS.Path(), nil } return "", nil } func getContainerNetIO(ctr *Container) (*netlink.LinkStatistics, error) { var netStats *netlink.LinkStatistics netNSPath, netPathErr := getContainerNetNS(ctr) if netPathErr != nil { return nil, netPathErr } if netNSPath == "" { // If netNSPath is empty, it was set as none, and no netNS was set up // this is a valid state and thus return no error, nor any statistics return nil, nil } err := ns.WithNetNSPath(netNSPath, func(_ ns.NetNS) error { link, err := netlink.LinkByName(ocicni.DefaultInterfaceName) if err != nil { return err } netStats = link.Attrs().Statistics return nil }) return netStats, err } func (c *Container) getContainerNetworkInfo(data *InspectContainerData) *InspectContainerData { if c.state.NetNS != nil && len(c.state.NetworkStatus) > 0 { // Report network settings from the first pod network result := c.state.NetworkStatus[0] // Go through our IP addresses for _, ctrIP := range result.IPs { ipWithMask := ctrIP.Address.String() splitIP := strings.Split(ipWithMask, "/") mask, _ := strconv.Atoi(splitIP[1]) if ctrIP.Version == "4" { data.NetworkSettings.IPAddress = splitIP[0] data.NetworkSettings.IPPrefixLen = mask data.NetworkSettings.Gateway = ctrIP.Gateway.String() } else { data.NetworkSettings.GlobalIPv6Address = splitIP[0] data.NetworkSettings.GlobalIPv6PrefixLen = mask data.NetworkSettings.IPv6Gateway = ctrIP.Gateway.String() } } // Set network namespace path data.NetworkSettings.SandboxKey = c.state.NetNS.Path() // Set MAC address of interface linked with network namespace path for _, i := range result.Interfaces { if i.Sandbox == data.NetworkSettings.SandboxKey { data.NetworkSettings.MacAddress = i.Mac } } } return data }