#166: Added support for the interface name in the config file

Makefile

@@ -3,6 +3,8 @@ NAME := glutton
 BUILDSTRING := $(shell git log --pretty=format:'%h' -n 1)
 VERSIONSTRING := $(NAME) version $(VERSION)+$(BUILDSTRING)
 BUILDDATE := $(shell date -u -Iseconds)
+CONFIG_FILE=config/config.yaml
+INTERFACE=$(shell grep 'interface:' $(CONFIG_FILE) | awk '{print $$2}')
 
 LDFLAGS := "-X \"main.VERSION=$(VERSIONSTRING)\" -X \"main.BUILDDATE=$(BUILDDATE)\""
 
@@ -30,7 +32,7 @@ clean:
 	rm -rf bin/
 
 run: build
-	sudo bin/server -i eth0
+	sudo bin/server -i $(INTERFACE)
 
 docker:
 	docker build -t glutton .

README.md

@@ -16,14 +16,19 @@ Arch:
 pacman -S gcc libpcap iptables
 ```
 
+Fedora:
+```
+sudo dnf install gcc libpcap-devel iptables
+```
+
 Build glutton:
 ```
 make build
 ```
 
 To run/test glutton:
 ```
-bin/server
+sudo bin/server
 ```
 
 To get this to work on WSL, use this kernel: https://github.com/Locietta/xanmod-kernel-WSL2

config/config.yaml

@@ -1,3 +1,8 @@
+interface: eth0
+tcpPort: 8080
+udpPort: 8081
+sshPort: 2222
+
 ports:
   tcp: 5000
   udp: 5001

glutton.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	_ "embed"
+	"flag"
 	"fmt"
 	"io"
 	"log/slog"
@@ -40,9 +41,18 @@ type Glutton struct {
 	publicAddrs         []net.IP
 }
 
+var (
+	interfaceName string
+)
+
 //go:embed config/rules.yaml
 var defaultRules []byte
 
+func init() {
+	flag.StringVar(&interfaceName, "i", "", "Network interface name")
+	flag.Parse()
+}
+
 func (g *Glutton) initConfig() error {
 	viper.SetConfigName("config")
 	viper.AddConfigPath(viper.GetString("confpath"))
@@ -58,6 +68,12 @@ func (g *Glutton) initConfig() error {
 	viper.SetDefault("max_tcp_payload", 4096)
 	viper.SetDefault("conn_timeout", 45)
 	viper.SetDefault("rules_path", "rules/rules.yaml")
+	viper.SetDefault("interface", "eth0") // Default interface name
+
+	if interfaceName == "" {
+		interfaceName = viper.GetString("interface")
+	}
+
 	g.Logger.Debug("configuration set successfully", slog.String("reporter", "glutton"))
 	return nil
 }
@@ -108,7 +124,7 @@ func New(ctx context.Context) (*Glutton, error) {
 // Init initializes server and handles
 func (g *Glutton) Init() error {
 	var err error
-	g.publicAddrs, err = getNonLoopbackIPs(viper.GetString("interface"))
+	g.publicAddrs, err = getNonLoopbackIPs(interfaceName)
 	if err != nil {
 		return err
 	}
@@ -241,11 +257,11 @@ func (g *Glutton) Start() error {
 	g.startMonitor()
 
 	sshPort := viper.GetUint32("ports.ssh")
-	if err := setTProxyIPTables(viper.GetString("interface"), g.publicAddrs[0].String(), "tcp", uint32(g.Server.tcpPort), sshPort); err != nil {
+	if err := setTProxyIPTables(interfaceName, g.publicAddrs[0].String(), "tcp", uint32(g.Server.tcpPort), sshPort); err != nil {
 		return err
 	}
 
-	if err := setTProxyIPTables(viper.GetString("interface"), g.publicAddrs[0].String(), "udp", uint32(g.Server.udpPort), sshPort); err != nil {
+	if err := setTProxyIPTables(interfaceName, g.publicAddrs[0].String(), "udp", uint32(g.Server.udpPort), sshPort); err != nil {
 		return err
 	}
 
@@ -353,11 +369,11 @@ func (g *Glutton) Shutdown() {
 	g.cancel() // close all connection
 
 	g.Logger.Info("Flushing TCP iptables")
-	if err := flushTProxyIPTables(viper.GetString("interface"), g.publicAddrs[0].String(), "tcp", uint32(g.Server.tcpPort), uint32(viper.GetInt("ports.ssh"))); err != nil {
+	if err := flushTProxyIPTables(interfaceName, g.publicAddrs[0].String(), "tcp", uint32(g.Server.tcpPort), uint32(viper.GetInt("ports.ssh"))); err != nil {
 		g.Logger.Error("Failed to drop tcp iptables", producer.ErrAttr(err))
 	}
 	g.Logger.Info("Flushing UDP iptables")
-	if err := flushTProxyIPTables(viper.GetString("interface"), g.publicAddrs[0].String(), "udp", uint32(g.Server.udpPort), uint32(viper.GetInt("ports.ssh"))); err != nil {
+	if err := flushTProxyIPTables(interfaceName, g.publicAddrs[0].String(), "udp", uint32(g.Server.udpPort), uint32(viper.GetInt("ports.ssh"))); err != nil {
 		g.Logger.Error("Failed to drop udp iptables", producer.ErrAttr(err))
 	}