package generate import ( "context" "net" "strconv" "strings" "github.com/containers/podman/v2/libpod/image" "github.com/containers/podman/v2/pkg/specgen" "github.com/cri-o/ocicni/pkg/ocicni" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) const ( protoTCP = "tcp" protoUDP = "udp" protoSCTP = "sctp" ) // Parse port maps to OCICNI port mappings. // Returns a set of OCICNI port mappings, and maps of utilized container and // host ports. func parsePortMapping(portMappings []specgen.PortMapping) ([]ocicni.PortMapping, map[string]map[string]map[uint16]uint16, map[string]map[string]map[uint16]uint16, error) { // First, we need to validate the ports passed in the specgen, and then // convert them into CNI port mappings. finalMappings := []ocicni.PortMapping{} // To validate, we need two maps: one for host ports, one for container // ports. // Each is a map of protocol to map of IP address to map of port to // port (for hostPortValidate, it's host port to container port; // for containerPortValidate, container port to host port. // These will ensure no collisions. hostPortValidate := make(map[string]map[string]map[uint16]uint16) containerPortValidate := make(map[string]map[string]map[uint16]uint16) // Initialize the first level of maps (we can't really guess keys for // the rest). for _, proto := range []string{protoTCP, protoUDP, protoSCTP} { hostPortValidate[proto] = make(map[string]map[uint16]uint16) containerPortValidate[proto] = make(map[string]map[uint16]uint16) } postAssignHostPort := false // Iterate through all port mappings, generating OCICNI PortMapping // structs and validating there is no overlap. for _, port := range portMappings { // First, check proto protocols, err := checkProtocol(port.Protocol, true) if err != nil { return nil, nil, nil, err } // Validate host IP hostIP := port.HostIP if hostIP == "" { hostIP = "0.0.0.0" } if ip := net.ParseIP(hostIP); ip == nil { return nil, nil, nil, errors.Errorf("invalid IP address %s in port mapping", port.HostIP) } // Validate port numbers and range. len := port.Range if len == 0 { len = 1 } containerPort := port.ContainerPort if containerPort == 0 { return nil, nil, nil, errors.Errorf("container port number must be non-0") } hostPort := port.HostPort if uint32(len-1)+uint32(containerPort) > 65535 { return nil, nil, nil, errors.Errorf("container port range exceeds maximum allowable port number") } if uint32(len-1)+uint32(hostPort) > 65536 { return nil, nil, nil, errors.Errorf("host port range exceeds maximum allowable port number") } // Iterate through ports, populating maps to check for conflicts // and generating CNI port mappings. for _, p := range protocols { hostIPMap := hostPortValidate[p] ctrIPMap := containerPortValidate[p] hostPortMap, ok := hostIPMap[hostIP] if !ok { hostPortMap = make(map[uint16]uint16) hostIPMap[hostIP] = hostPortMap } ctrPortMap, ok := ctrIPMap[hostIP] if !ok { ctrPortMap = make(map[uint16]uint16) ctrIPMap[hostIP] = ctrPortMap } // Iterate through all port numbers in the requested // range. var index uint16 for index = 0; index < len; index++ { cPort := containerPort + index hPort := hostPort + index if cPort == 0 { return nil, nil, nil, errors.Errorf("container port cannot be 0") } // Host port is allowed to be 0. If it is, we // select a random port on the host. // This will happen *after* all other ports are // placed, to ensure we don't accidentally // select a port that a later mapping wanted. if hPort == 0 { // If we already have a host port // assigned to their container port - // just use that. if ctrPortMap[cPort] != 0 { hPort = ctrPortMap[cPort] } else { postAssignHostPort = true } } else { testHPort := hostPortMap[hPort] if testHPort != 0 && testHPort != cPort { return nil, nil, nil, errors.Errorf("conflicting port mappings for host port %d (protocol %s)", hPort, p) } hostPortMap[hPort] = cPort // Mapping a container port to multiple // host ports is allowed. // We only store the latest of these in // the container port map - we don't // need to know all of them, just one. testCPort := ctrPortMap[cPort] ctrPortMap[cPort] = hPort // If we have an exact duplicate, just continue if testCPort == hPort && testHPort == cPort { continue } } // We appear to be clear. Make an OCICNI port // struct. // Don't use hostIP - we want to preserve the // empty string hostIP by default for compat. cniPort := ocicni.PortMapping{ HostPort: int32(hPort), ContainerPort: int32(cPort), Protocol: p, HostIP: port.HostIP, } finalMappings = append(finalMappings, cniPort) } } } // Handle any 0 host ports now by setting random container ports. if postAssignHostPort { remadeMappings := make([]ocicni.PortMapping, 0, len(finalMappings)) // Iterate over all for _, p := range finalMappings { if p.HostPort != 0 { remadeMappings = append(remadeMappings, p) continue } hostIPMap := hostPortValidate[p.Protocol] ctrIPMap := containerPortValidate[p.Protocol] hostPortMap, ok := hostIPMap[p.HostIP] if !ok { hostPortMap = make(map[uint16]uint16) hostIPMap[p.HostIP] = hostPortMap } ctrPortMap, ok := ctrIPMap[p.HostIP] if !ok { ctrPortMap = make(map[uint16]uint16) ctrIPMap[p.HostIP] = ctrPortMap } // See if container port has been used elsewhere if ctrPortMap[uint16(p.ContainerPort)] != 0 { // Duplicate definition. Let's not bother // including it. continue } // Max retries to ensure we don't loop forever. for i := 0; i < 15; i++ { candidate, err := getRandomPort() if err != nil { return nil, nil, nil, errors.Wrapf(err, "error getting candidate host port for container port %d", p.ContainerPort) } if hostPortMap[uint16(candidate)] == 0 { logrus.Debugf("Successfully assigned container port %d to host port %d (IP %s Protocol %s)", p.ContainerPort, candidate, p.HostIP, p.Protocol) hostPortMap[uint16(candidate)] = uint16(p.ContainerPort) ctrPortMap[uint16(p.ContainerPort)] = uint16(candidate) p.HostPort = int32(candidate) break } } if p.HostPort == 0 { return nil, nil, nil, errors.Errorf("could not find open host port to map container port %d to", p.ContainerPort) } remadeMappings = append(remadeMappings, p) } return remadeMappings, containerPortValidate, hostPortValidate, nil } return finalMappings, containerPortValidate, hostPortValidate, nil } // Make final port mappings for the container func createPortMappings(ctx context.Context, s *specgen.SpecGenerator, img *image.Image) ([]ocicni.PortMapping, error) { finalMappings, containerPortValidate, hostPortValidate, err := parsePortMapping(s.PortMappings) if err != nil { return nil, err } // If not publishing exposed ports, or if we are publishing and there is // nothing to publish - then just return the port mappings we've made so // far. if !s.PublishExposedPorts || (len(s.Expose) == 0 && img == nil) { return finalMappings, nil } logrus.Debugf("Adding exposed ports") // We need to merge s.Expose into image exposed ports expose := make(map[uint16]string) for k, v := range s.Expose { expose[k] = v } if img != nil { inspect, err := img.InspectNoSize(ctx) if err != nil { return nil, errors.Wrapf(err, "error inspecting image to get exposed ports") } for imgExpose := range inspect.Config.ExposedPorts { // Expose format is portNumber[/protocol] splitExpose := strings.SplitN(imgExpose, "/", 2) num, err := strconv.Atoi(splitExpose[0]) if err != nil { return nil, errors.Wrapf(err, "unable to convert image EXPOSE statement %q to port number", imgExpose) } if num > 65535 || num < 1 { return nil, errors.Errorf("%d from image EXPOSE statement %q is not a valid port number", num, imgExpose) } // No need to validate protocol, we'll do it below. if len(splitExpose) == 1 { expose[uint16(num)] = "tcp" } else { expose[uint16(num)] = splitExpose[1] } } } // There's been a request to expose some ports. Let's do that. // Start by figuring out what needs to be exposed. // This is a map of container port number to protocols to expose. toExpose := make(map[uint16][]string) for port, proto := range expose { // Validate protocol first protocols, err := checkProtocol(proto, false) if err != nil { return nil, errors.Wrapf(err, "error validating protocols for exposed port %d", port) } if port == 0 { return nil, errors.Errorf("cannot expose 0 as it is not a valid port number") } // Check to see if the port is already present in existing // mappings. for _, p := range protocols { ctrPortMap, ok := containerPortValidate[p]["0.0.0.0"] if !ok { ctrPortMap = make(map[uint16]uint16) containerPortValidate[p]["0.0.0.0"] = ctrPortMap } if portNum := ctrPortMap[port]; portNum == 0 { // We want to expose this port for this protocol exposeProto, ok := toExpose[port] if !ok { exposeProto = []string{} } exposeProto = append(exposeProto, p) toExpose[port] = exposeProto } } } // We now have a final list of ports that we want exposed. // Let's find empty, unallocated host ports for them. for port, protocols := range toExpose { for _, p := range protocols { // Find an open port on the host. // I see a faint possibility that this will infinite // loop trying to find a valid open port, so I've // included a max-tries counter. hostPort := 0 tries := 15 for hostPort == 0 && tries > 0 { // We can't select a specific protocol, which is // unfortunate for the UDP case. candidate, err := getRandomPort() if err != nil { return nil, err } // Check if the host port is already bound hostPortMap, ok := hostPortValidate[p]["0.0.0.0"] if !ok { hostPortMap = make(map[uint16]uint16) hostPortValidate[p]["0.0.0.0"] = hostPortMap } if checkPort := hostPortMap[uint16(candidate)]; checkPort != 0 { // Host port is already allocated, try again tries-- continue } hostPortMap[uint16(candidate)] = port hostPort = candidate logrus.Debugf("Mapping exposed port %d/%s to host port %d", port, p, hostPort) // Make a CNI port mapping cniPort := ocicni.PortMapping{ HostPort: int32(candidate), ContainerPort: int32(port), Protocol: p, HostIP: "", } finalMappings = append(finalMappings, cniPort) } if tries == 0 && hostPort == 0 { // We failed to find an open port. return nil, errors.Errorf("failed to find an open port to expose container port %d on the host", port) } } } return finalMappings, nil } // Check a string to ensure it is a comma-separated set of valid protocols func checkProtocol(protocol string, allowSCTP bool) ([]string, error) { protocols := make(map[string]struct{}) splitProto := strings.Split(protocol, ",") // Don't error on duplicates - just deduplicate for _, p := range splitProto { p = strings.ToLower(p) switch p { case protoTCP, "": protocols[protoTCP] = struct{}{} case protoUDP: protocols[protoUDP] = struct{}{} case protoSCTP: if !allowSCTP { return nil, errors.Errorf("protocol SCTP is not allowed for exposed ports") } protocols[protoSCTP] = struct{}{} default: return nil, errors.Errorf("unrecognized protocol %q in port mapping", p) } } finalProto := []string{} for p := range protocols { finalProto = append(finalProto, p) } // This shouldn't be possible, but check anyways if len(finalProto) == 0 { return nil, errors.Errorf("no valid protocols specified for port mapping") } return finalProto, nil } // Find a random, open port on the host func getRandomPort() (int, error) { l, err := net.Listen("tcp", ":0") if err != nil { return 0, errors.Wrapf(err, "unable to get free TCP port") } defer l.Close() _, randomPort, err := net.SplitHostPort(l.Addr().String()) if err != nil { return 0, errors.Wrapf(err, "unable to determine free port") } rp, err := strconv.Atoi(randomPort) if err != nil { return 0, errors.Wrapf(err, "unable to convert random port to int") } return rp, nil }