package libpod import ( "crypto/rand" "fmt" "net" "os" "path/filepath" "strings" "syscall" cnitypes "github.com/containernetworking/cni/pkg/types/current" "github.com/containernetworking/plugins/pkg/ns" "github.com/cri-o/ocicni/pkg/ocicni" "github.com/pkg/errors" "github.com/projectatomic/libpod/utils" "github.com/sirupsen/logrus" "golang.org/x/sys/unix" ) // Get an OCICNI network config func getPodNetwork(id, name, nsPath string, ports []ocicni.PortMapping) ocicni.PodNetwork { return 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, } } // Create and configure a new network namespace for a container func (r *Runtime) configureNetNS(ctr *Container, ctrNS ns.NetNS) (err error) { podNetwork := getPodNetwork(ctr.ID(), ctr.Name(), ctrNS.Path(), ctr.config.PortMappings) result, err := r.netPlugin.SetUpPod(podNetwork) if err != nil { return 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) } } }() logrus.Debugf("Response from CNI plugins: %v", result.String()) resultStruct, err := cnitypes.GetResult(result) if err != nil { return errors.Wrapf(err, "error parsing result from CNI plugins") } ctr.state.NetNS = ctrNS ctr.state.IPs = resultStruct.IPs ctr.state.Routes = resultStruct.Routes // We need to temporarily use iptables to allow the container // to resolve DNS until this issue is fixed upstream. // https://github.com/containernetworking/plugins/pull/75 if resultStruct.IPs != nil { for _, ip := range resultStruct.IPs { iptablesDNS("-I", ip.Address.IP.String()) } } return nil } // Create and configure a new network namespace for a container func (r *Runtime) createNetNS(ctr *Container) (err error) { ctrNS, err := ns.NewNS() if err != nil { return errors.Wrapf(err, "error creating network namespace for container %s", ctr.ID()) } defer func() { if err != nil { 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()) return r.configureNetNS(ctr, ctrNS) } // 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 } return r.configureNetNS(ctr, netNS) } // iptablesDNS accepts an arg (-I|-D) and IP address of the container and then // generates an iptables command to either add or subtract the needed rule func iptablesDNS(arg, ip string) error { iptablesCmd := []string{"-t", "filter", arg, "FORWARD", "-s", ip, "!", "-o", ip, "-j", "ACCEPT"} logrus.Debug("Running iptables command: ", strings.Join(iptablesCmd, " ")) _, err := utils.ExecCmd("iptables", iptablesCmd...) if err != nil { logrus.Error(err) } 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 } // Get a container's IP address func (r *Runtime) getContainerIP(ctr *Container) (net.IP, error) { if ctr.state.NetNS == nil { return nil, errors.Wrapf(ErrInvalidArg, "container %s has no network namespace, cannot get IP", ctr.ID()) } podNetwork := getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.PortMappings) ipStr, err := r.netPlugin.GetPodNetworkStatus(podNetwork) if err != nil { return nil, errors.Wrapf(err, "error retrieving network status of container %s", ctr.ID()) } ip := net.ParseIP(ipStr) if ip == nil { return nil, errors.Wrapf(ErrInternal, "error parsing IP address %s for container %s", ipStr, ctr.ID()) } return ip, nil } // Tear down a network namespace func (r *Runtime) teardownNetNS(ctr *Container) error { if ctr.state.NetNS == nil { // The container has no network namespace, we're set return nil } // Because we are using iptables to allow the container to resolve DNS // on per IP address, we also need to try to remove the iptables rule // on cleanup. Remove when https://github.com/containernetworking/plugins/pull/75 // is merged. for _, ip := range ctr.state.IPs { iptablesDNS("-D", ip.Address.IP.String()) } logrus.Debugf("Tearing down network namespace at %s for container %s", ctr.state.NetNS.Path(), ctr.ID()) podNetwork := getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.PortMappings) // The network may have already been torn down, so don't fail here, just log if err := r.netPlugin.TearDownPod(podNetwork); err != nil { logrus.Errorf("Failed to tear down network namespace for container %s: %v", ctr.ID(), err) } nsPath := ctr.state.NetNS.Path() if err := ctr.state.NetNS.Close(); err != nil { return errors.Wrapf(err, "error closing network namespace for container %s", ctr.ID()) } // We need to unconditionally try to unmount/remove the namespace // because we may be in a separate process from the one that created the // namespace, and Close() will only do that if it is the same process. if err := unix.Unmount(nsPath, unix.MNT_DETACH); err != nil { if err != syscall.EINVAL && err != syscall.ENOENT { return errors.Wrapf(err, "error unmounting network namespace %s for container %s", nsPath, ctr.ID()) } } if err := os.RemoveAll(nsPath); err != nil && !os.IsNotExist(err) { return errors.Wrapf(err, "error removing network namespace %s for container %s", nsPath, ctr.ID()) } ctr.state.NetNS = nil return nil }