Replace netstat from net-tools by ip from iproute2 (linux)

net/net.go

@@ -4,20 +4,12 @@ import (
 	"fmt"
 	"net"
 	"regexp"
-	"runtime"
 	"strconv"
 	"strings"
 
 	"github.com/evilsocket/bettercap-ng/core"
 )
 
-var IPv4RouteParser = regexp.MustCompile("^([\\d\\.]+)\\s+([\\d\\.]+)\\s+([\\d\\.]+)\\s+([A-Z]+)\\s+\\d+\\s+\\d+\\s+\\d+\\s+(.+)$")
-var IPv4RouteTokens = 6
-var IPv4RouteParserMac = regexp.MustCompile("^([a-z]+)+\\s+(\\d+\\.+\\d+.\\d.+\\d)+\\s+([a-zA-z]+)+\\s+(\\d+)+\\s+(\\d+)+\\s+([a-zA-Z]+\\d+)$")
-var IPv4RouteTokensMac = 7
-var IPv4RouteGWFlags = "UG"
-var IPv4RouteGWFlagsMac = "UGSc"
-
 func FindInterface(name string) (*Endpoint, error) {
 	ifaces, err := net.Interfaces()
 	if err != nil {
@@ -75,35 +67,15 @@ func FindInterface(name string) (*Endpoint, error) {
 }
 
 func FindGateway(iface *Endpoint) (*Endpoint, error) {
-	var routeParser = IPv4RouteParser
-	var routeTokens = IPv4RouteTokens
-	var flagsIndex = 4
-	var ifnameIndex = 5
-	var gwFlags = IPv4RouteGWFlags
-
-	if runtime.GOOS == "darwin" {
-		// "MacOS detected"
-		routeParser = IPv4RouteParserMac
-		routeTokens = IPv4RouteTokensMac
-		flagsIndex = 3
-		ifnameIndex = 6
-		gwFlags = IPv4RouteGWFlagsMac
-	}
-
-	output, err := core.Exec("netstat", []string{"-n", "-r"})
+	output, err := core.Exec(IPv4RouteCmd, IPv4RouteCmdOpts)
 	if err != nil {
 		return nil, err
 	}
 
 	for _, line := range strings.Split(output, "\n") {
-		m := routeParser.FindStringSubmatch(line)
-		if len(m) == routeTokens {
-			// destination := m[1]
-			// mask := m[3]
-			flags := m[flagsIndex]
-			ifname := m[ifnameIndex]
-			if ifname == iface.Name() && flags == gwFlags {
-				gateway := m[2]
+		m := IPv4RouteParser.FindStringSubmatch(line)
+		if len(m) == IPv4RouteTokens {
+			return IPv4RouteIsGateway(iface.Name(), m, func(gateway string) (*Endpoint, error) {
 				if gateway == iface.IpAddress {
 					return iface, nil
 				} else {
@@ -114,7 +86,7 @@ func FindGateway(iface *Endpoint) (*Endpoint, error) {
 					}
 					return NewEndpoint(gateway, mac), nil
 				}
-			}
+			})
 		}
 	}
 

net/net_darwin.go

@@ -0,0 +1,20 @@
+package net
+
+import "regexp"
+
+var IPv4RouteParser = regexp.MustCompile("^([a-z]+)+\\s+(\\d+\\.+\\d+.\\d.+\\d)+\\s+([a-zA-z]+)+\\s+(\\d+)+\\s+(\\d+)+\\s+([a-zA-Z]+\\d+)$")
+var IPv4RouteTokens = 7
+var IPv4RouteCmd = "netstat"
+var IPv4RouteCmdOpts = []string{"-n", "-r"}
+
+func IPv4RouteIsGateway(ifname string, tokens []string, f func(gateway string) (*Endpoint, error)) (*Endpoint, error) {
+	ifname2 := tokens[6]
+	flags := tokens[3]
+
+	if ifname == ifname2 && flags == "UGSc" {
+		gateway := tokens[2]
+		return f(gateway)
+	}
+
+	return nil, nil
+}

net/net_linux.go

@@ -0,0 +1,20 @@
+package net
+
+import "regexp"
+
+// only matches gateway lines
+var IPv4RouteParser = regexp.MustCompile("^(default|[0-9\\.]+)\\svia\\s([0-9\\.]+)\\sdev\\s(\\w+)\\s.*$")
+var IPv4RouteTokens = 4
+var IPv4RouteCmd = "ip"
+var IPv4RouteCmdOpts = []string{"route"}
+
+func IPv4RouteIsGateway(ifname string, tokens []string, f func(gateway string) (*Endpoint, error)) (*Endpoint, error) {
+	ifname2 := tokens[3]
+
+	if ifname == ifname2 {
+		gateway := tokens[2]
+		return f(gateway)
+	}
+
+	return nil, nil
+}