From 892a7bee22a1bb02d3b4da6d270c65b6e4e1321a Mon Sep 17 00:00:00 2001
From: Yuhui Xu <xuyh0120@outlook.com>
Date: Fri, 8 Jul 2022 21:14:11 -0400
Subject: [PATCH] frontend: support listening on unix socket (#54)

---
 frontend/main.go      | 42 +++++++++++++++++++++++++++++-------------
 frontend/webserver.go |  5 +++--
 2 files changed, 32 insertions(+), 15 deletions(-)

diff --git a/frontend/main.go b/frontend/main.go
index 979605f..f91c618 100644
--- a/frontend/main.go
+++ b/frontend/main.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"flag"
+	"net"
 	"os"
 	"strconv"
 	"strings"
@@ -101,18 +102,18 @@ func main() {
 	if env := os.Getenv("BIRDLG_NAME_FILTER"); env != "" {
 		settingDefault.nameFilter = env
 	}
-        if env := os.Getenv("BIRDLG_TIMEOUT"); env != "" {
-                var err error
-                if settingDefault.timeOut, err = strconv.Atoi(env); err != nil {
-                        panic(err)
-                }
-        }
+	if env := os.Getenv("BIRDLG_TIMEOUT"); env != "" {
+		var err error
+		if settingDefault.timeOut, err = strconv.Atoi(env); err != nil {
+			panic(err)
+		}
+	}
 
 	serversPtr := flag.String("servers", strings.Join(settingDefault.servers, ","), "server name prefixes, separated by comma")
 	domainPtr := flag.String("domain", settingDefault.domain, "server name domain suffixes")
 	proxyPortPtr := flag.Int("proxy-port", settingDefault.proxyPort, "port bird-lgproxy is running on")
 	whoisPtr := flag.String("whois", settingDefault.whoisServer, "whois server for queries")
-	listenPtr := flag.String("listen", settingDefault.listen, "address bird-lg is listening on")
+	listenPtr := flag.String("listen", settingDefault.listen, "address or unix socket bird-lg is listening on")
 	dnsInterfacePtr := flag.String("dns-interface", settingDefault.dnsInterface, "dns zone to query ASN information")
 	netSpecificModePtr := flag.String("net-specific-mode", settingDefault.netSpecificMode, "network specific operation mode, [(none)|dn42]")
 	titleBrandPtr := flag.String("title-brand", settingDefault.titleBrand, "prefix of page titles in browser tabs")
@@ -132,11 +133,6 @@ func main() {
 		panic("no server set")
 	}
 
-	if !strings.Contains(*listenPtr, ":") {
-		listenHost := ":" + (*listenPtr)
-		listenPtr = &listenHost
-	}
-
 	servers := strings.Split(*serversPtr, ",")
 	serversDisplay := strings.Split(*serversPtr, ",")
 
@@ -177,5 +173,25 @@ func main() {
 	}
 
 	ImportTemplates()
-	webServerStart()
+
+	var l net.Listener
+	var err error
+
+	if strings.HasPrefix(setting.listen, "/") {
+		// Delete existing socket file, ignore errors (will fail later anyway)
+		os.Remove(setting.listen)
+		l, err = net.Listen("unix", setting.listen)
+	} else {
+		listenAddr := setting.listen
+		if !strings.Contains(listenAddr, ":") {
+			listenAddr = ":" + listenAddr
+		}
+		l, err = net.Listen("tcp", listenAddr)
+	}
+
+	if err != nil {
+		panic(err)
+	}
+
+	webServerStart(l)
 }
diff --git a/frontend/webserver.go b/frontend/webserver.go
index 926978d..9bd589a 100644
--- a/frontend/webserver.go
+++ b/frontend/webserver.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"html"
 	"io/fs"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
@@ -176,7 +177,7 @@ func webHandlerBGPMap(endpoint string, command string) func(w http.ResponseWrite
 }
 
 // set up routing paths and start webserver
-func webServerStart() {
+func webServerStart(l net.Listener) {
 
 	// redirect main page to all server summary
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
@@ -211,5 +212,5 @@ func webServerStart() {
 	http.HandleFunc("/telegram/", webHandlerTelegramBot)
 
 	// Start HTTP server
-	http.ListenAndServe(setting.listen, handlers.LoggingHandler(os.Stdout, http.DefaultServeMux))
+	http.Serve(l, handlers.LoggingHandler(os.Stdout, http.DefaultServeMux))
 }