Derek解读Bytom源码-P2P网络 upnp端口映射
作者:Derek
简介
Github地址:https://github.com/Bytom/bytom
Gitee地址:https://gitee.com/BytomBlockc...
本章介绍bytom代码P2P网络中upnp端口映射
作者使用MacOS操作系统,其他平台也大同小异Golang Version: 1.8
UPNP介绍
UPNP(Universal Plug and Play)通用即插即用。UPNP端口映射将一个外部端口映射到一个内网ip:port。从而实现p2p网络从外网能够穿透网关访问到内网的bytomd节点。
UPNP协议
SSDP(Simple Service Discovery Protocol 简单服务发现协议)
GENA(Generic Event Notification Architecture 通用事件通知结构)
SOAP(Simple Object Access Protocol 简单对象访问协议)
XML(Extensible Markup Language 可扩张标记语言)
UPNP代码
p2p/upnp/upnp.go
发现网络中支持UPNP功能的设备
从网络中发现支持UPNP功能的设备,并得到该设备的location和url等相关信息
type upnpNAT struct { serviceURL string // 设备的描述文件URL,用于得到该设备的描述信息 ourIP string // 节点本地ip地址 urnDomain string // 设备类型 } func Discover() (nat NAT, err error) { ssdp, err := net.ResolveUDPAddr("udp4", "239.255.255.250:1900") if err != nil { return } conn, err := net.ListenPacket("udp4", ":0") if err != nil { return } socket := conn.(*net.UDPConn) defer socket.Close() err = socket.SetDeadline(time.Now().Add(3 * time.Second)) if err != nil { return } st := "InternetGatewayDevice:1" // 多播请求:M-SEARCH SSDP协议定义的发现请求。 buf := bytes.NewBufferString( "M-SEARCH * HTTP/1.1\r\n" + "HOST: 239.255.255.250:1900\r\n" + "ST: ssdp:all\r\n" + "MAN: \"ssdp:discover\"\r\n" + "MX: 2\r\n\r\n") message := buf.Bytes() answerBytes := make([]byte, 1024) for i := 0; i < 3; i++ { // 向239.255.255.250:1900发送一条多播请求 _, err = socket.WriteToUDP(message, ssdp) if err != nil { return } // 如果从网络中发现UPNP设备则会从239.255.255.250:1900收到响应消息 var n int n, _, err = socket.ReadFromUDP(answerBytes) for { n, _, err = socket.ReadFromUDP(answerBytes) if err != nil { break } answer := string(answerBytes[0:n]) if strings.Index(answer, st) < 0 { continue } // HTTP header field names are case-insensitive. // http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 // 获得设备location locString := "\r\nlocation:" answer = strings.ToLower(answer) locIndex := strings.Index(answer, locString) if locIndex < 0 { continue } loc := answer[locIndex+len(locString):] endIndex := strings.Index(loc, "\r\n") if endIndex < 0 { continue } // 获得设备的描述url和设备类型 locURL := strings.TrimSpace(loc[0:endIndex]) var serviceURL, urnDomain string serviceURL, urnDomain, err = getServiceURL(locURL) if err != nil { return } var ourIP net.IP ourIP, err = localIPv4() if err != nil { return } nat = &upnpNAT{serviceURL: serviceURL, ourIP: ourIP.String(), urnDomain: urnDomain} return } } err = errors.New("UPnP port discovery failed.") return }
添加端口映射
向upnp设备发送一条http post请求,将内部网络ip:port和外部网络ip:port做映射
func (n *upnpNAT) AddPortMapping(protocol string, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error) { // A single concatenation would break ARM compilation. message := "<u:AddPortMapping xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" + "<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(externalPort) message += "</NewExternalPort><NewProtocol>" + protocol + "</NewProtocol>" message += "<NewInternalPort>" + strconv.Itoa(internalPort) + "</NewInternalPort>" + "<NewInternalClient>" + n.ourIP + "</NewInternalClient>" + "<NewEnabled>1</NewEnabled><NewPortMappingDescription>" message += description + "</NewPortMappingDescription><NewLeaseDuration>" + strconv.Itoa(timeout) + "</NewLeaseDuration></u:AddPortMapping>" var response *http.Response response, err = soapRequest(n.serviceURL, "AddPortMapping", message, n.urnDomain) if response != nil { defer response.Body.Close() } if err != nil { return } // TODO: check response to see if the port was forwarded // log.Println(message, response) // JAE: // body, err := ioutil.ReadAll(response.Body) // fmt.Println(string(body), err) mappedExternalPort = externalPort _ = response return }
删除端口映射
向upnp设备发送一条http post请求,将内部网络ip:port和外部网络ip:port删除映射关系
func (n *upnpNAT) DeletePortMapping(protocol string, externalPort, internalPort int) (err error) { message := "<u:DeletePortMapping xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" + "<NewRemoteHost></NewRemoteHost><NewExternalPort>" + strconv.Itoa(externalPort) + "</NewExternalPort><NewProtocol>" + protocol + "</NewProtocol>" + "</u:DeletePortMapping>" var response *http.Response response, err = soapRequest(n.serviceURL, "DeletePortMapping", message, n.urnDomain) if response != nil { defer response.Body.Close() } if err != nil { return } // TODO: check response to see if the port was deleted // log.Println(message, response) _ = response return }
获取映射后的公网地址
func (n *upnpNAT) GetExternalAddress() (addr net.IP, err error) { info, err := n.getExternalIPAddress() if err != nil { return } addr = net.ParseIP(info.externalIpAddress) return } func (n *upnpNAT) getExternalIPAddress() (info statusInfo, err error) { message := "<u:GetExternalIPAddress xmlns:u=\"urn:" + n.urnDomain + ":service:WANIPConnection:1\">\r\n" + "</u:GetExternalIPAddress>" var response *http.Response response, err = soapRequest(n.serviceURL, "GetExternalIPAddress", message, n.urnDomain) if response != nil { defer response.Body.Close() } if err != nil { return } var envelope Envelope data, err := ioutil.ReadAll(response.Body) reader := bytes.NewReader(data) xml.NewDecoder(reader).Decode(&envelope) info = statusInfo{envelope.Soap.ExternalIP.IPAddress} if err != nil { return } return }
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