116 lines
2.2 KiB
Go
116 lines
2.2 KiB
Go
package nat
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import (
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"net"
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"time"
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"github.com/jackpal/gateway"
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"github.com/jackpal/go-nat-pmp"
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)
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var (
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_ NAT = (*natpmpNAT)(nil)
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)
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func discoverNATPMP() <-chan NAT {
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res := make(chan NAT, 1)
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ip, err := gateway.DiscoverGateway()
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if err == nil {
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go discoverNATPMPWithAddr(res, ip)
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}
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return res
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}
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func discoverNATPMPWithAddr(c chan NAT, ip net.IP) {
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client := natpmp.NewClient(ip)
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_, err := client.GetExternalAddress()
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if err != nil {
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return
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}
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c <- &natpmpNAT{client, ip, make(map[int]int)}
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}
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type natpmpNAT struct {
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c *natpmp.Client
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gateway net.IP
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ports map[int]int
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}
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func (n *natpmpNAT) GetDeviceAddress() (addr net.IP, err error) {
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return n.gateway, nil
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}
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func (n *natpmpNAT) GetInternalAddress() (addr net.IP, err error) {
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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for _, iface := range ifaces {
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addrs, err := iface.Addrs()
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if err != nil {
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return nil, err
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}
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for _, addr := range addrs {
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switch x := addr.(type) {
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case *net.IPNet:
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if x.Contains(n.gateway) {
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return x.IP, nil
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}
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}
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}
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}
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return nil, ErrNoInternalAddress
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}
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func (n *natpmpNAT) GetExternalAddress() (addr net.IP, err error) {
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res, err := n.c.GetExternalAddress()
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if err != nil {
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return nil, err
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}
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d := res.ExternalIPAddress
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return net.IPv4(d[0], d[1], d[2], d[3]), nil
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}
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func (n *natpmpNAT) AddPortMapping(protocol string, internalPort int, description string, timeout time.Duration) (int, error) {
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var (
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err error
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)
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timeoutInSeconds := int(timeout / time.Second)
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if externalPort := n.ports[internalPort]; externalPort > 0 {
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_, err = n.c.AddPortMapping(protocol, internalPort, externalPort, timeoutInSeconds)
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if err == nil {
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n.ports[internalPort] = externalPort
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return externalPort, nil
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}
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}
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for i := 0; i < 3; i++ {
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externalPort := randomPort()
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_, err = n.c.AddPortMapping(protocol, internalPort, externalPort, timeoutInSeconds)
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if err == nil {
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n.ports[internalPort] = externalPort
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return externalPort, nil
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}
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}
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return 0, err
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}
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func (n *natpmpNAT) DeletePortMapping(protocol string, internalPort int) (err error) {
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delete(n.ports, internalPort)
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return nil
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}
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func (n *natpmpNAT) Type() string {
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return "NAT-PMP"
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}
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