proxy: autodetect traceroute args on startup (#69)

README.md

@@ -79,6 +79,8 @@ Configuration is handled by [viper](https://github.com/spf13/viper), any config
 | name_filter | --name-filter | BIRDLG_NAME_FILTER | protocol names to hide in summary tables (RE2 syntax); defaults to none if not set |
 | timeout | --time-out | BIRDLG_TIMEOUT | time before request timed out, in seconds; defaults to 120 if not set |
 
+### Examples
+
 Example: the following command starts the frontend with 2 BIRD nodes, with domain name "gigsgigscloud.dn42.lantian.pub" and "hostdare.dn42.lantian.pub", and proxies are running on port 8000 on both nodes.
 
 ```bash
@@ -122,16 +124,32 @@ Configuration can be set in:
 
 Configuration is handled by [viper](https://github.com/spf13/viper), any config format supported by it can be used.
 
-> Note: the config system is replaced with viper only recently (2022-07-08). If some config items do not work, please open an issue, and use commit [892a7bee22a1bb02d3b4da6d270c65b6e4e1321a](https://github.com/xddxdd/bird-lg-go/tree/892a7bee22a1bb02d3b4da6d270c65b6e4e1321a) (last version before config system replace) for the time being.
-
 | Config Key | Parameter | Environment Variable | Description |
 | ---------- | --------- | -------------------- | ----------- |
 | allowed_ips | --allowed | ALLOWED_IPS | IPs allowed to access this proxy, separated by commas. Don't set to allow all IPs. (default "") |
 | bird_socket | --bird | BIRD_SOCKET | socket file for bird, set either in parameter or environment variable BIRD_SOCKET (default "/var/run/bird/bird.ctl") |
 | listen | --listen | BIRDLG_PROXY_PORT | listen address, set either in parameter or environment variable  BIRDLG_PROXY_PORT(default "8000") |
-| traceroute_bin | --traceroute_bin | BIRDLG_TRACEROUTE_BIN | traceroute binary file, set either in parameter or environment variable  BIRDLG_TRACEROUTE_BIN(default "traceroute") |
+| traceroute_bin | --traceroute_bin | BIRDLG_TRACEROUTE_BIN | traceroute binary file, set either in parameter or environment variable  BIRDLG_TRACEROUTE_BIN |
+| traceroute_flags | --traceroute_flags | BIRDLG_TRACEROUTE_FLAGS | traceroute flags, repeat for multiple flags. |
 | traceroute_raw | --traceroute_raw | BIRDLG_TRACEROUTE_RAW | whether to display traceroute outputs raw (default false) |
 
+### Traceroute Binary Autodetection
+
+If `traceroute_bin` or `traceroute_flags` is not set, then on startup, the proxy will try to `traceroute 127.0.0.1` with different traceroute binaries and arguments, in order to use the most optimized setting available, while maintaining compatibility with multiple variants of traceroute binaries.
+
+Traceroute binaries will be autodetected in the following order:
+
+1. If `traceroute_bin` is set:
+   1. `[traceroute_bin] -q1 -N32 -w1 127.0.0.1` (Corresponds to Traceroute on Debian)
+   2. `[traceroute_bin] -q1 -w1 127.0.0.1` (Corresponds to Traceroute on FreeBSD)
+   3. `[traceroute_bin] 127.0.0.1` (Corresponds to Busybox Traceroute)
+2. `mtr -w -c1 -Z1 -G1 -b 127.0.0.1` (MTR)
+3. `traceroute -q1 -N32 -w1 127.0.0.1` (Corresponds to Traceroute on Debian)
+4. `traceroute -q1 -w1 127.0.0.1` (Corresponds to Traceroute on FreeBSD)
+5. `traceroute 127.0.0.1` (Corresponds to Busybox Traceroute)
+
+### Examples
+
 Example: start proxy with default configuration, should work "out of the box" on Debian 9 with BIRDv1:
 
 ```bash

proxy/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"net"
 	"net/http"
 	"os"
@@ -54,6 +55,7 @@ type settingType struct {
 	listen     string
 	allowedIPs []string
 	tr_bin     string
+	tr_flags   []string
 	tr_raw     bool
 }
 
@@ -62,6 +64,9 @@ var setting settingType
 // Wrapper of tracer
 func main() {
 	parseSettings()
+	tracerouteAutodetect()
+
+	fmt.Printf("Listening on %s...\n", setting.listen)
 
 	var l net.Listener
 	var err error

proxy/settings.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/google/shlex"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
 )
@@ -13,6 +14,7 @@ type viperSettingType struct {
 	Listen          string `mapstructure:"listen"`
 	AllowedIPs      string `mapstructure:"allowed_ips"`
 	TracerouteBin   string `mapstructure:"traceroute_bin"`
+	TracerouteFlags string `mapstructure:"traceroute_flags"`
 	TracerouteRaw   bool   `mapstructure:"traceroute_raw"`
 }
 
@@ -39,9 +41,12 @@ func parseSettings() {
 	pflag.String("allowed", "", "IPs allowed to access this proxy, separated by commas. Don't set to allow all IPs.")
 	viper.BindPFlag("allowed_ips", pflag.Lookup("allowed"))
 
-	pflag.String("traceroute_bin", "traceroute", "traceroute binary file, set either in parameter or environment variable BIRDLG_TRACEROUTE_BIN")
+	pflag.String("traceroute_bin", "", "traceroute binary file, set either in parameter or environment variable BIRDLG_TRACEROUTE_BIN")
 	viper.BindPFlag("traceroute_bin", pflag.Lookup("traceroute_bin"))
 
+	pflag.String("traceroute_flags", "", "traceroute flags, repeat for multiple flags.")
+	viper.BindPFlag("traceroute_flags", pflag.Lookup("traceroute_flags"))
+
 	pflag.Bool("traceroute_raw", false, "whether to display traceroute outputs raw; set via parameter or environment variable BIRDLG_TRACEROUTE_RAW")
 	viper.BindPFlag("traceroute_raw", pflag.Lookup("traceroute_raw"))
 
@@ -65,7 +70,13 @@ func parseSettings() {
 		setting.allowedIPs = []string{""}
 	}
 
+	var err error
 	setting.tr_bin = viperSettings.TracerouteBin
+	setting.tr_flags, err = shlex.Split(viperSettings.TracerouteFlags)
+	if err != nil {
+		panic(err)
+	}
+
 	setting.tr_raw = viperSettings.TracerouteRaw
 
 	fmt.Printf("%#v\n", setting)

proxy/traceroute.go

@@ -5,28 +5,81 @@ import (
 	"net/http"
 	"os/exec"
 	"regexp"
-	"runtime"
 	"strconv"
 	"strings"
 
 	"github.com/google/shlex"
 )
 
-func tracerouteTryExecute(cmd []string, args [][]string) ([]byte, string) {
+func tracerouteArgsToString(cmd string, args []string, target []string) string {
-	var output []byte
+	var cmdCombined = append([]string{cmd}, args...)
-	var errString = ""
+	cmdCombined = append(cmdCombined, target...)
-	for i := range cmd {
+	return strings.Join(cmdCombined, " ")
-		var err error
+}
-		var cmdCombined = cmd[i] + " " + strings.Join(args[i], " ")
 
-		instance := exec.Command(cmd[i], args[i]...)
+func tracerouteTryExecute(cmd string, args []string, target []string) ([]byte, error) {
-		output, err = instance.CombinedOutput()
+	instance := exec.Command(cmd, append(args, target...)...)
+	output, err := instance.CombinedOutput()
 	if err == nil {
-			return output, ""
+		return output, nil
 	}
-		errString += fmt.Sprintf("+ (Try %d) %s\n%s\n\n", (i + 1), cmdCombined, output)
+
+	return output, err
+}
+
+func tracerouteDetect(cmd string, args []string) bool {
+	target := []string{"127.0.0.1"}
+	success := false
+	if result, err := tracerouteTryExecute(cmd, args, target); err == nil {
+		setting.tr_bin = cmd
+		setting.tr_flags = args
+		success = true
+		fmt.Printf("Traceroute autodetect success: %s\n", tracerouteArgsToString(cmd, args, target))
+	} else {
+		fmt.Printf("Traceroute autodetect fail, continuing: %s (%s)\n%s", tracerouteArgsToString(cmd, args, target), err.Error(), result)
 	}
-	return nil, errString
+
+	return success
+}
+
+func tracerouteAutodetect() {
+	if setting.tr_bin != "" && setting.tr_flags != nil {
+		return
+	}
+
+	// Traceroute (custom binary)
+	if setting.tr_bin != "" {
+		if tracerouteDetect(setting.tr_bin, []string{"-q1", "-N32", "-w1"}) {
+			return
+		}
+		if tracerouteDetect(setting.tr_bin, []string{"-q1", "-w1"}) {
+			return
+		}
+		if tracerouteDetect(setting.tr_bin, []string{}) {
+			return
+		}
+	}
+
+	// MTR
+	if tracerouteDetect("mtr", []string{"-w", "-c1", "-Z1", "-G1", "-b"}) {
+		return
+	}
+
+	// Traceroute
+	if tracerouteDetect("traceroute", []string{"-q1", "-N32", "-w1"}) {
+		return
+	}
+	if tracerouteDetect("traceroute", []string{"-q1", "-w1"}) {
+		return
+	}
+	if tracerouteDetect("traceroute", []string{}) {
+		return
+	}
+
+	// Unsupported
+	setting.tr_bin = ""
+	setting.tr_flags = nil
+	println("Traceroute autodetect failed! Traceroute will be disabled")
 }
 
 func tracerouteHandler(httpW http.ResponseWriter, httpR *http.Request) {
@@ -44,52 +97,30 @@ func tracerouteHandler(httpW http.ResponseWriter, httpR *http.Request) {
 		}
 
 		var result []byte
-		var errString string
 		skippedCounter := 0
 
-		if runtime.GOOS == "freebsd" || runtime.GOOS == "netbsd" || runtime.GOOS == "openbsd" {
+		if setting.tr_bin == "" {
-			result, errString = tracerouteTryExecute(
-				[]string{
-					setting.tr_bin,
-					setting.tr_bin,
-				},
-				[][]string{
-					append([]string{"-q1", "-w1"}, args...),
-					args,
-				},
-			)
-		} else if runtime.GOOS == "linux" {
-			result, errString = tracerouteTryExecute(
-				[]string{
-					setting.tr_bin,
-					setting.tr_bin,
-					setting.tr_bin,
-				},
-				[][]string{
-					append([]string{"-q1", "-N32", "-w1"}, args...),
-					append([]string{"-q1", "-w1"}, args...),
-					args,
-				},
-			)
-		} else {
 			httpW.WriteHeader(http.StatusInternalServerError)
 			httpW.Write([]byte("traceroute not supported on this node.\n"))
 			return
 		}
-		if errString != "" {
+
+		result, err = tracerouteTryExecute(setting.tr_bin, setting.tr_flags, args)
+		if err != nil {
 			httpW.WriteHeader(http.StatusInternalServerError)
-			httpW.Write([]byte(errString))
+			httpW.Write([]byte(fmt.Sprintf("Error executing traceroute: %s\n\n", err.Error())))
 		}
+
 		if result != nil {
 			if setting.tr_raw {
 				httpW.Write(result)
 			} else {
-				errString = string(result)
+				resultString := string(result)
-				errString = regexp.MustCompile(`(?m)^\s*(\d*)\s*\*\n`).ReplaceAllStringFunc(errString, func(w string) string {
+				resultString = regexp.MustCompile(`(?m)^\s*(\d*)\s*\*\n`).ReplaceAllStringFunc(resultString, func(w string) string {
 					skippedCounter++
 					return ""
 				})
-				httpW.Write([]byte(strings.TrimSpace(errString)))
+				httpW.Write([]byte(strings.TrimSpace(resultString)))
 				if skippedCounter > 0 {
 					httpW.Write([]byte("\n\n" + strconv.Itoa(skippedCounter) + " hops not responding."))
 				}