基于 faas、http 的 tcp 隧道

Example negotiation
The client connects to the proxy server and requests tunneling by specifying the port and the host computer to which it would like to connect. The port is used to indicate the protocol being requested.[3]

CONNECT streamline.t-mobile.com:22 HTTP/1.1
Proxy-Authorization: Basic encoded-credentials
If the connection was allowed and the proxy has connected to the specified host then the proxy will return a 2XX success response.[3]

HTTP/1.1 200 OK

sequenceDiagram
local->>client: tcp 代理本地的请求
client->>server: http 请求，类型: connect 
server->>remote: tcp 连接到远端, 读写数据
client->>server: http 请求，类型: write 
client->>server: http 请求，类型: read 
client->>local: tcp 请求返回

const Name = "http"


type HttpClient struct {
	client *resty.Client
	addr   string
}

func NewHttpClient(url *url.URL) (proxy.Client, error) {
	return &HttpClient{
		client: resty.New(),
		addr:   url.String(),
	}, nil
}

func (c *HttpClient) Handshake(_ net.Conn, target string) (io.ReadWriter, error) {
	conn := &httpConnection{
		client:       c,
		target:       target,
		connectionId: RandStringRunes(8),
	}
	return conn, conn.Connect()
}

func (c *HttpClient) post(r *TunnelRequest) (*TunnelResponse, error) {
	ret := &TunnelResponse{}
	_, err := c.client.NewRequest().SetResult(ret).SetBody(r).SetHeader("Content-Type", "application/json").Post(c.addr)
	return ret, err
}

type TunnelRequest struct {
	Target       string
	Action       string // create, read, write
	Data         []byte
	ConnectionId string
}

type TunnelResponse struct {
	Target       string
	Action       string
	Data         []byte
	ConnectionId string
	Eof          bool
	Code         int
	Message      string
}

type httpConnection struct {
	client       *HttpClient
	target       string
	readBuffer   []byte
	writeBuffer  []byte
	connectionId string
	eof          bool
	lastWrite    time.Time
}

func (c *httpConnection) Connect() (err error) {
	_, err = c.client.post(&TunnelRequest{
		Target:       c.target,
		Action:       "connect",
		ConnectionId: c.connectionId,
	})
	return err
}

func (c *httpConnection) Read(p []byte) (n int, err error) {
	if c.eof {
		return 0, io.EOF
	}
	if len(c.readBuffer) == 0 {
		resp, err := c.client.post(&TunnelRequest{
			Target:       c.target,
			Action:       "read",
			ConnectionId: c.connectionId,
		})
		if err != nil {
			return 0, err
		}
		c.readBuffer = append(c.readBuffer, resp.Data...)
		if resp.Eof {
			c.eof = true
		}
	}

	n = copy(p, c.readBuffer)
	c.readBuffer = c.readBuffer[:len(c.readBuffer)-n]
	return n, nil
}

func (c *httpConnection) Write(p []byte) (n int, err error) {
	c.writeBuffer = append(c.writeBuffer, p...)
	if len(c.writeBuffer) > 1024 || time.Now().Sub(c.lastWrite) > time.Millisecond*100 {
		resp, err := c.client.post(&TunnelRequest{
			Target:       c.target,
			Action:       "write",
			Data:         c.writeBuffer,
			ConnectionId: c.connectionId,
		})
		if err != nil {
			return 0, err
		}
		_ = resp
		c.writeBuffer = c.writeBuffer[:0]
	}
	return len(p), nil
}

# client 端启动
➜ go build -o main .
v2simple/cmd/client on  master by 🐹 v1.16 ☪️  21:29:49
➜ ./main -f client.example.http.json
V2Simple 0.1.0 (V2Simple, a simple implementation of V2Ray 4.25.0), go1.16 darwin amd64
2021/09/25 21:30:02 using /Users/leiwang/Work/go-librarys/src/github.com/u2takey/v2simple/cmd/client/client.example.http.json
2021/09/25 21:30:02 using /Users/leiwang/Work/go-librarys/src/github.com/u2takey/v2simple/cmd/client/blacklist
2021/09/25 21:30:02 socks5 listening TCP on 127.0.0.1:1081

# server 端启动
ubuntu@VM-0-7-ubuntu:~$ ./main
[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.

[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:	export GIN_MODE=release
 - using code:	gin.SetMode(gin.ReleaseMode)

[GIN-debug] POST   /                         --> main.main.func1 (3 handlers)
[GIN-debug] Listening and serving HTTP on :8081