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108 lines
2.3 KiB
108 lines
2.3 KiB
package nat |
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import ( |
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"context" |
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"fmt" |
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"net" |
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"sync" |
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upnp "github.com/NebulousLabs/go-upnp" |
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) |
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// Compile-time check to ensure UPnP implements the Traversal interface. |
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var _ Traversal = (*UPnP)(nil) |
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// UPnP is a concrete implementation of the Traversal interface that uses the |
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// UPnP technique. |
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type UPnP struct { |
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device *upnp.IGD |
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forwardedPortsMtx sync.Mutex |
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forwardedPorts map[uint16]struct{} |
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} |
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// DiscoverUPnP scans the local network for a UPnP enabled device. |
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func DiscoverUPnP(ctx context.Context) (*UPnP, error) { |
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// Scan the local network for a UPnP-enabled device. |
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device, err := upnp.DiscoverCtx(ctx) |
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if err != nil { |
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return nil, err |
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} |
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u := &UPnP{ |
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device: device, |
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forwardedPorts: make(map[uint16]struct{}), |
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} |
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// We'll then attempt to retrieve the external IP address of this |
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// device to ensure it is not behind multiple NATs. |
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if _, err := u.ExternalIP(); err != nil { |
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return nil, err |
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} |
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return u, nil |
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} |
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// ExternalIP returns the external IP address of the UPnP enabled device. |
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func (u *UPnP) ExternalIP() (net.IP, error) { |
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ip, err := u.device.ExternalIP() |
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if err != nil { |
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return nil, err |
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} |
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if isPrivateIP(net.ParseIP(ip)) { |
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return nil, ErrMultipleNAT |
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} |
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return net.ParseIP(ip), nil |
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} |
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// AddPortMapping enables port forwarding for the given port. |
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func (u *UPnP) AddPortMapping(port uint16) error { |
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u.forwardedPortsMtx.Lock() |
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defer u.forwardedPortsMtx.Unlock() |
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if err := u.device.Forward(port, ""); err != nil { |
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return err |
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} |
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u.forwardedPorts[port] = struct{}{} |
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return nil |
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} |
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// DeletePortMapping disables port forwarding for the given port. |
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func (u *UPnP) DeletePortMapping(port uint16) error { |
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u.forwardedPortsMtx.Lock() |
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defer u.forwardedPortsMtx.Unlock() |
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if _, exists := u.forwardedPorts[port]; !exists { |
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return fmt.Errorf("port %d is not being forwarded", port) |
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} |
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if err := u.device.Clear(port); err != nil { |
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return err |
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} |
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delete(u.forwardedPorts, port) |
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return nil |
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} |
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// ForwardedPorts returns a list of ports currently being forwarded. |
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func (u *UPnP) ForwardedPorts() []uint16 { |
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u.forwardedPortsMtx.Lock() |
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defer u.forwardedPortsMtx.Unlock() |
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ports := make([]uint16, 0, len(u.forwardedPorts)) |
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for port := range u.forwardedPorts { |
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ports = append(ports, port) |
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} |
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return ports |
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} |
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// Name returns the name of the specific NAT traversal technique used. |
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func (u *UPnP) Name() string { |
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return "UPnP" |
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}
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