Use proxy-protocol to pass through source IP to nginx

controllers/nginx/pkg/cmd/controller/nginx.go

@@ -88,6 +88,7 @@ func newNGINXController() ingress.Controller {
 				Hostname: "localhost",
 				IP:       "127.0.0.1",
 				Port:     442,
+				ProxyProtocol: true,
 			},
 		},
 	}
@@ -531,10 +532,12 @@ func (n *NGINXController) OnUpdate(ingressCfg ingress.Configuration) ([]byte, er
 			}
 		}
 
+		//TODO: Allow PassthroughBackends to specify they support proxy-protocol
 		servers = append(servers, &server{
 			Hostname: pb.Hostname,
 			IP:       svc.Spec.ClusterIP,
 			Port:     port,
+			ProxyProtocol: false,
 		})
 	}
 

controllers/nginx/pkg/cmd/controller/tcp.go

@@ -13,6 +13,7 @@ type server struct {
 	Hostname string
 	IP       string
 	Port     int
+	ProxyProtocol bool
 }
 
 type proxy struct {
@@ -61,10 +62,31 @@ func (p *proxy) Handle(conn net.Conn) {
 	}
 	defer clientConn.Close()
 
+	if proxy.ProxyProtocol {
+		//Write out the proxy-protocol header
+		localAddr := conn.LocalAddr().(*net.TCPAddr)
+		remoteAddr := conn.RemoteAddr().(*net.TCPAddr)
+		protocol := "UNKNOWN"
+		if remoteAddr.IP.To4() != nil {
+			protocol = "TCP4"
+		} else if remoteAddr.IP.To16() != nil {
+			protocol = "TCP6"
+		}
+		proxyProtocolHeader := fmt.Sprintf("PROXY %s %s %s %d %d\r\n", protocol, remoteAddr.IP.String(), localAddr.IP.String(), remoteAddr.Port, localAddr.Port)
+		glog.V(4).Infof("Writing proxy protocol header - %s", proxyProtocolHeader)
+		_, err = fmt.Fprintf(clientConn, proxyProtocolHeader)
+	}
+	if err != nil {
+		glog.Errorf("unexpected error writing proxy-protocol header: %s", err)
+		clientConn.Close()
+	} else {
 		_, err = clientConn.Write(data[:length])
 		if err != nil {
+			glog.Errorf("unexpected error writing first 4k of proxy data: %s", err)
 			clientConn.Close()
 		}
+	}
+
 	pipe(clientConn, conn)
 }
 

controllers/nginx/rootfs/etc/nginx/template/nginx.tmpl

@@ -230,9 +230,9 @@ http {
         {{ if $IsIPV6Enabled }}listen [::]:80{{ if $cfg.UseProxyProtocol }} proxy_protocol{{ end }}{{ if eq $server.Hostname "_"}} default_server reuseport backlog={{ $backlogSize }}{{ end }};{{ end }}
 
         {{/* Listen on 442 because port 443 is used in the TLS sni server */}}
-        {{/* This listen on port 442 cannot contains proxy_protocol directive because port 443 is in charge of decoding the protocol */}}
+        {{/* This listener must always have proxy_protocol enabled, because the SNI listener forwards on source IP info in it. */}}
-        {{ if not (empty $server.SSLCertificate) }}listen 442{{ if eq $server.Hostname "_"}} default_server reuseport backlog={{ $backlogSize }}{{end}} ssl {{ if $cfg.UseHTTP2 }}http2{{ end }};
+        {{ if not (empty $server.SSLCertificate) }}listen 442 proxy_protocol{{ if eq $server.Hostname "_"}} default_server reuseport backlog={{ $backlogSize }}{{end}} ssl {{ if $cfg.UseHTTP2 }}http2{{ end }};
-        {{ if $IsIPV6Enabled }}{{ if not (empty $server.SSLCertificate) }}listen [::]:442{{ end }} {{ if eq $server.Hostname "_"}} default_server reuseport backlog={{ $backlogSize }}{{end}} ssl {{ if $cfg.UseHTTP2 }}http2{{ end }};{{ end }}
+        {{ if $IsIPV6Enabled }}{{ if not (empty $server.SSLCertificate) }}listen [::]:442 proxy_protocol{{ end }} {{ if eq $server.Hostname "_"}} default_server reuseport backlog={{ $backlogSize }}{{end}} ssl {{ if $cfg.UseHTTP2 }}http2{{ end }};{{ end }}
         {{/* comment PEM sha is required to detect changes in the generated configuration and force a reload */}}
         # PEM sha: {{ $server.SSLPemChecksum }}
         ssl_certificate                         {{ $server.SSLCertificate }};