bytom源码分析-P2P网络-upnp端口映射

简介
https://github.com/Bytom/bytom
本章介绍bytom代码P2P网络中upnp端口映射
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作者使用MacOS操作系统，其他平台也大同小异
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Golang Version: 1.8' a; Q) G8 E( `3 {

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
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 := "\r\n" +
"" + strconv.Itoa(externalPort)
message += "" + protocol + ""
message += "" + strconv.Itoa(internalPort) + "" +
"" + n.ourIP + "" +
"1"
message += description +
"" + strconv.Itoa(timeout) +
""
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 := "\r\n" +
"" + strconv.Itoa(externalPort) +
"" + protocol + "" +
""
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 := "\r\n" +
""
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
}
感谢比原社区开发者Derek的辛勤写作
如果你对比原项目有兴趣请添加微信号：matrix2140 咨询，备注blockflow

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