diff options
Diffstat (limited to 'pkg/specgen/generate/ports.go')
| -rw-r--r-- | pkg/specgen/generate/ports.go | 333 |
1 files changed, 333 insertions, 0 deletions
diff --git a/pkg/specgen/generate/ports.go b/pkg/specgen/generate/ports.go new file mode 100644 index 000000000..91c8e68d1 --- /dev/null +++ b/pkg/specgen/generate/ports.go @@ -0,0 +1,333 @@ +package generate + +import ( + "context" + "net" + "strconv" + "strings" + + "github.com/containers/libpod/libpod/image" + "github.com/containers/libpod/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) + } + + // 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 hostPort == 0 { + hostPort = containerPort + } + 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 || hPort == 0 { + return nil, nil, nil, errors.Errorf("host and container ports cannot be 0") + } + + testCPort := ctrPortMap[cPort] + if testCPort != 0 && testCPort != hPort { + // This is an attempt to redefine a port + return nil, nil, nil, errors.Errorf("conflicting port mappings for container port %d (protocol %s)", cPort, p) + } + ctrPortMap[cPort] = hPort + + 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 + + // 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) + } + } + } + + 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 { + 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 +} |