WIP Implement proxy-protocol v1 support for TCP server

Makefile

@@ -71,7 +71,8 @@ deps: clean-deps
 	github.com/inconshreveable/mousetrap \
 	github.com/gin-contrib/cors \
 	github.com/lxc/lxd \
-	github.com/jtopjian/lxdhelpers
+	github.com/jtopjian/lxdhelpers \
+	github.com/pires/go-proxyproto
 
 clean-dist:
 	rm -rf ./dist/${VERSION}
@@ -98,7 +99,7 @@ dist:
 	  else \
 		  cd $$distpath && zip -r ../../${NAME}_${VERSION}_$$1_$$2.zip . && cd - ;\
 	  fi \
-	done 
+	done
 
 build-container-latest: build
 	@echo Building docker container LATEST
@@ -107,4 +108,3 @@ build-container-latest: build
 build-container-tagged: build
 	@echo Building docker container ${VERSION}
 	docker build -t yyyar/gobetween:${VERSION} .
-

src/config/config.go

@@ -73,6 +73,9 @@ type Server struct {
 	// tcp | udp | tls
 	Protocol string `toml:"protocol" json:"protocol"`
 
+	// v1
+	ProxyProtocol string `toml:"proxy_protocol" json:"proxy_protocol"`
+
 	// weight | leastconn | roundrobin
 	Balance string `toml:"balance" json:"balance"`
 

src/server/tcp/server.go

@@ -21,6 +21,7 @@ import (
 	"../../logging"
 	"../../stats"
 	"../../utils"
+	"../../utils/proxyprotocol"
 	tlsutil "../../utils/tls"
 	"../../utils/tls/sni"
 	"../modules/access"
@@ -342,6 +343,13 @@ func (this *Server) handle(ctx *core.TcpContext) {
 	defer this.scheduler.DecrementConnection(*backend)
 
 	/* Stat proxying */
+	if this.cfg.ProxyProtocol == "v1" {
+		log.Debug("Sending proxy-protocol header ", clientConn.RemoteAddr(), " -> ", this.listener.Addr(), " -> ", backendConn.RemoteAddr())
+		err := proxyprotocol.SendProxyProtocolV1(clientConn, backendConn)
+		if err != nil {
+			log.Error(err)
+		}
+	}
 	log.Debug("Begin ", clientConn.RemoteAddr(), " -> ", this.listener.Addr(), " -> ", backendConn.RemoteAddr())
 	cs := proxy(clientConn, backendConn, utils.ParseDurationOrDefault(*this.cfg.BackendIdleTimeout, 0))
 	bs := proxy(backendConn, clientConn, utils.ParseDurationOrDefault(*this.cfg.ClientIdleTimeout, 0))

src/utils/proxyprotocol/proxyprotocol.go

@@ -0,0 +1,62 @@
+package proxyprotocol
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+
+	proxyproto "github.com/pires/go-proxyproto"
+)
+
+func addrToIPAndPort(addr net.Addr) (ip net.IP, port uint16, err error) {
+	ipString, portString, err := net.SplitHostPort(addr.String())
+	if err != nil {
+		return
+	}
+
+	ip = net.ParseIP(ipString)
+	if ip == nil {
+		err = fmt.Errorf("Could not parse IP")
+		return
+	}
+
+	p, err := strconv.ParseInt(portString, 10, 64)
+	if err != nil {
+		return
+	}
+	port = uint16(p)
+	return
+}
+
+/// SendProxyProtocolV1 sends a proxy protocol v1 header to initialize the connection
+/// https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt
+func SendProxyProtocolV1(client net.Conn, backend net.Conn) error {
+	sourceIP, sourcePort, err := addrToIPAndPort(client.RemoteAddr())
+	if err != nil {
+		return err
+	}
+
+	destinationIP, destinationPort, err := addrToIPAndPort(client.LocalAddr())
+	if err != nil {
+		return err
+	}
+
+	h := proxyproto.Header{
+		Version:            1,
+		SourceAddress:      sourceIP,
+		SourcePort:         sourcePort,
+		DestinationAddress: destinationIP,
+		DestinationPort:    destinationPort,
+	}
+	if sourceIP.To4() != nil {
+		h.TransportProtocol = proxyproto.TCPv4
+	} else {
+		h.TransportProtocol = proxyproto.TCPv6
+	}
+
+	_, err = h.WriteTo(backend)
+	if err != nil {
+		return nil
+	}
+	return nil
+}