mirror of https://github.com/docker/docs.git
104 lines
2.0 KiB
Go
104 lines
2.0 KiB
Go
package portallocator
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import (
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"errors"
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"github.com/dotcloud/docker/pkg/collections"
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"sync"
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)
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type portMappings map[string]*collections.OrderedIntSet
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const (
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BeginPortRange = 49153
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EndPortRange = 65535
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)
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var (
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ErrPortAlreadyAllocated = errors.New("port has already been allocated")
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ErrPortExceedsRange = errors.New("port exceeds upper range")
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ErrUnknownProtocol = errors.New("unknown protocol")
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)
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var (
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lock = sync.Mutex{}
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allocatedPorts = portMappings{}
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availablePorts = portMappings{}
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)
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func init() {
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allocatedPorts["udp"] = collections.NewOrderedIntSet()
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availablePorts["udp"] = collections.NewOrderedIntSet()
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allocatedPorts["tcp"] = collections.NewOrderedIntSet()
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availablePorts["tcp"] = collections.NewOrderedIntSet()
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}
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// RequestPort returns an available port if the port is 0
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// If the provided port is not 0 then it will be checked if
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// it is available for allocation
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func RequestPort(proto string, port int) (int, error) {
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lock.Lock()
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defer lock.Unlock()
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if err := validateProtocol(proto); err != nil {
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return 0, err
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}
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var (
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allocated = allocatedPorts[proto]
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available = availablePorts[proto]
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)
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if port != 0 {
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if allocated.Exists(port) {
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return 0, ErrPortAlreadyAllocated
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}
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available.Remove(port)
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allocated.Push(port)
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return port, nil
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}
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next := available.Pop()
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if next == 0 {
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next = allocated.PullBack()
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if next == 0 {
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next = BeginPortRange
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} else {
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next++
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}
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if next > EndPortRange {
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return 0, ErrPortExceedsRange
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}
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}
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allocated.Push(next)
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return next, nil
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}
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// ReleasePort will return the provided port back into the
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// pool for reuse
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func ReleasePort(proto string, port int) error {
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lock.Lock()
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defer lock.Unlock()
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if err := validateProtocol(proto); err != nil {
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return err
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}
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var (
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allocated = allocatedPorts[proto]
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available = availablePorts[proto]
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)
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allocated.Remove(port)
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available.Push(port)
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return nil
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}
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func validateProtocol(proto string) error {
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if _, exists := allocatedPorts[proto]; !exists {
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return ErrUnknownProtocol
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}
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return nil
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}
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