github.com/yinchengtsinghua/golang-Eos-dpos-Ethereum@v0.0.0-20190121132951-92cc4225ed8e/p2p/nat/natupnp.go

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//版权所有2015 Go Ethereum作者
//此文件是Go以太坊库的一部分。
//
//Go-Ethereum库是免费软件：您可以重新分发它和/或修改
//根据GNU发布的较低通用公共许可证的条款
//自由软件基金会，或者许可证的第3版，或者
//（由您选择）任何更高版本。
//
//Go以太坊图书馆的发行目的是希望它会有用，
//但没有任何保证；甚至没有
//适销性或特定用途的适用性。见
//GNU较低的通用公共许可证，了解更多详细信息。
//
//你应该收到一份GNU较低级别的公共许可证副本
//以及Go以太坊图书馆。如果没有，请参见<http://www.gnu.org/licenses/>。

package nat

import (
	"errors"
	"fmt"
	"net"
	"strings"
	"time"

	"github.com/huin/goupnp"
	"github.com/huin/goupnp/dcps/internetgateway1"
	"github.com/huin/goupnp/dcps/internetgateway2"
)

const soapRequestTimeout = 3 * time.Second

type upnp struct {
	dev     *goupnp.RootDevice
	service string
	client  upnpClient
}

type upnpClient interface {
	GetExternalIPAddress() (string, error)
	AddPortMapping(string, uint16, string, uint16, string, bool, string, uint32) error
	DeletePortMapping(string, uint16, string) error
	GetNATRSIPStatus() (sip bool, nat bool, err error)
}

func (n *upnp) ExternalIP() (addr net.IP, err error) {
	ipString, err := n.client.GetExternalIPAddress()
	if err != nil {
		return nil, err
	}
	ip := net.ParseIP(ipString)
	if ip == nil {
		return nil, errors.New("bad IP in response")
	}
	return ip, nil
}

func (n *upnp) AddMapping(protocol string, extport, intport int, desc string, lifetime time.Duration) error {
	ip, err := n.internalAddress()
	if err != nil {
		return nil
	}
	protocol = strings.ToUpper(protocol)
	lifetimeS := uint32(lifetime / time.Second)
	n.DeleteMapping(protocol, extport, intport)
	return n.client.AddPortMapping("", uint16(extport), protocol, uint16(intport), ip.String(), true, desc, lifetimeS)
}

func (n *upnp) internalAddress() (net.IP, error) {
	devaddr, err := net.ResolveUDPAddr("udp4", n.dev.URLBase.Host)
	if err != nil {
		return nil, err
	}
	ifaces, err := net.Interfaces()
	if err != nil {
		return nil, err
	}
	for _, iface := range ifaces {
		addrs, err := iface.Addrs()
		if err != nil {
			return nil, err
		}
		for _, addr := range addrs {
			if x, ok := addr.(*net.IPNet); ok && x.Contains(devaddr.IP) {
				return x.IP, nil
			}
		}
	}
	return nil, fmt.Errorf("could not find local address in same net as %v", devaddr)
}

func (n *upnp) DeleteMapping(protocol string, extport, intport int) error {
	return n.client.DeletePortMapping("", uint16(extport), strings.ToUpper(protocol))
}

func (n *upnp) String() string {
	return "UPNP " + n.service
}

//Discoverupnp搜索Internet网关设备
//并返回在本地网络上找到的第一个。
func discoverUPnP() Interface {
	found := make(chan *upnp, 2)
//IGDV1
	go discover(found, internetgateway1.URN_WANConnectionDevice_1, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp {
		switch sc.Service.ServiceType {
		case internetgateway1.URN_WANIPConnection_1:
			return &upnp{dev, "IGDv1-IP1", &internetgateway1.WANIPConnection1{ServiceClient: sc}}
		case internetgateway1.URN_WANPPPConnection_1:
			return &upnp{dev, "IGDv1-PPP1", &internetgateway1.WANPPPConnection1{ServiceClient: sc}}
		}
		return nil
	})
//IGDV2
	go discover(found, internetgateway2.URN_WANConnectionDevice_2, func(dev *goupnp.RootDevice, sc goupnp.ServiceClient) *upnp {
		switch sc.Service.ServiceType {
		case internetgateway2.URN_WANIPConnection_1:
			return &upnp{dev, "IGDv2-IP1", &internetgateway2.WANIPConnection1{ServiceClient: sc}}
		case internetgateway2.URN_WANIPConnection_2:
			return &upnp{dev, "IGDv2-IP2", &internetgateway2.WANIPConnection2{ServiceClient: sc}}
		case internetgateway2.URN_WANPPPConnection_1:
			return &upnp{dev, "IGDv2-PPP1", &internetgateway2.WANPPPConnection1{ServiceClient: sc}}
		}
		return nil
	})
	for i := 0; i < cap(found); i++ {
		if c := <-found; c != nil {
			return c
		}
	}
	return nil
}

//查找与给定目标匹配的设备并为所有设备调用Matcher
//每个设备的广告服务。找到第一个非零服务
//被送出去。如果没有匹配的服务，则发送nil。
func discover(out chan<- *upnp, target string, matcher func(*goupnp.RootDevice, goupnp.ServiceClient) *upnp) {
	devs, err := goupnp.DiscoverDevices(target)
	if err != nil {
		out <- nil
		return
	}
	found := false
	for i := 0; i < len(devs) && !found; i++ {
		if devs[i].Root == nil {
			continue
		}
		devs[i].Root.Device.VisitServices(func(service *goupnp.Service) {
			if found {
				return
			}
//检查匹配的IGD服务
			sc := goupnp.ServiceClient{
				SOAPClient: service.NewSOAPClient(),
				RootDevice: devs[i].Root,
				Location:   devs[i].Location,
				Service:    service,
			}
			sc.SOAPClient.HTTPClient.Timeout = soapRequestTimeout
			upnp := matcher(devs[i].Root, sc)
			if upnp == nil {
				return
			}
//检查是否启用端口映射
			if _, nat, err := upnp.client.GetNATRSIPStatus(); err != nil || !nat {
				return
			}
			out <- upnp
			found = true
		})
	}
	if !found {
		out <- nil
	}
}