fix: refactored routing logic (fixes #701)

network/net.go

@@ -305,7 +305,6 @@ func SetInterfaceTxPower(name string, txpower int) error {
 }
 
 func GatewayProvidedByUser(iface *Endpoint, gateway string) (*Endpoint, error) {
-	Debug("GatewayProvidedByUser(%s) [cmd=%v opts=%v parser=%v]", gateway, IPv4RouteCmd, IPv4RouteCmdOpts, IPv4RouteParser)
 	if IPv4Validator.MatchString(gateway) {
 		Debug("valid gateway ip %s", gateway)
 		// we have the address, now we need its mac

network/net_darwin.go

@@ -13,23 +13,8 @@ import (
 
 const airPortPath = "/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport"
 
-var IPv4RouteParser = regexp.MustCompile(`([^\s]+)\s+([^\s]+)\s+([^\s]+)\s+([^\s]+).*`)
-var IPv4RouteTokens = 5
-var IPv4RouteCmd = "netstat"
-var IPv4RouteCmdOpts = []string{"-n", "-r"}
 var WiFiChannelParser = regexp.MustCompile(`(?m)^.*Supported Channels: (.*)$`)
 
-func IPv4RouteIsGateway(ifname string, tokens []string, f func(gateway string) (*Endpoint, error)) (*Endpoint, error) {
-	flags := tokens[3]
-	ifname2 := tokens[4]
-	if ifname == ifname2 && flags == "UGSc" {
-		gateway := tokens[2]
-		return f(gateway)
-	}
-
-	return nil, nil
-}
-
 // see Windows version to understand why ....
 func getInterfaceName(iface net.Interface) string {
 	return iface.Name

network/net_gateway.go

@@ -3,47 +3,27 @@
 package network
 
 import (
-	"strings"
+	"github.com/bettercap/bettercap/routing"
-
-	"github.com/bettercap/bettercap/core"
-
-	"github.com/evilsocket/islazy/str"
 )
 
 func FindGateway(iface *Endpoint) (*Endpoint, error) {
-	Debug("FindGateway(%s) [cmd=%v opts=%v parser=%v]", iface.Name(), IPv4RouteCmd, IPv4RouteCmdOpts, IPv4RouteParser)
+	gateway, err := routing.Gateway(routing.IPv4, iface.Name())
-
-	output, err := core.Exec(IPv4RouteCmd, IPv4RouteCmdOpts)
 	if err != nil {
-		Debug("FindGateway(%s): core.Exec failed with %s", err)
 		return nil, err
 	}
 
-	Debug("FindGateway(%s) output:\n%s", iface.Name(), output)
-
-	ifName := iface.Name()
-	for _, line := range strings.Split(output, "\n") {
-		if line = str.Trim(line); strings.Contains(line, ifName) {
-			m := IPv4RouteParser.FindStringSubmatch(line)
-			if len(m) >= IPv4RouteTokens {
-				Debug("FindGateway(%s) line '%s' matched with %v", iface.Name(), line, m)
-				return IPv4RouteIsGateway(ifName, m, func(gateway string) (*Endpoint, error) {
 	if gateway == iface.IpAddress {
 		Debug("gateway is the interface")
 		return iface, nil
 	} else {
 		// we have the address, now we need its mac
-						mac, err := ArpLookup(ifName, gateway, false)
+		mac, err := ArpLookup(iface.Name(), gateway, false)
 		if err != nil {
 			return nil, err
 		}
 		Debug("gateway is %s[%s]", gateway, mac)
 		return NewEndpoint(gateway, mac), nil
 	}
-				})
-			}
-		}
-	}
 
 	Debug("FindGateway(%s): nothing found :/", iface.Name())
 	return nil, ErrNoGateway

network/net_linux.go

@@ -11,23 +11,6 @@ import (
 	"github.com/bettercap/bettercap/core"
 )
 
-// only matches gateway lines
-var IPv4RouteParser = regexp.MustCompile(`^(default|[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)\svia\s([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)\sdev\s(\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
-}
-
 // see Windows version to understand why ....
 func getInterfaceName(iface net.Interface) string {
 	return iface.Name

network/net_windows.go

@@ -3,25 +3,11 @@ package network
 import (
 	"fmt"
 	"net"
-	"regexp"
 	"strings"
 
 	"github.com/google/gopacket/pcap"
 )
 
-// only matches gateway lines
-var IPv4RouteParser = regexp.MustCompile("^.+\\s+.+\\s+\\d+\\s+([0-9\\.]+/\\d+)\\s+\\d+\\s+([0-9\\.]+).*$")
-var IPv4RouteTokens = 3
-var IPv4RouteCmd = "netsh"
-var IPv4RouteCmdOpts = []string{"interface", "ipv4", "show", "route"}
-
-func IPv4RouteIsGateway(ifname string, tokens []string, f func(gateway string) (*Endpoint, error)) (*Endpoint, error) {
-	// TODO check if the subnet is the same as iface ?
-	// subnet := tokens[1]
-	gateway := tokens[2]
-	return f(gateway)
-}
-
 /*
  * net.Interface does not have the correct name on Windows and pcap.Interface
  * does not have the hardware address for some reason ... so this is what I

routing/route.go

@@ -0,0 +1,17 @@
+package routing
+
+type RouteType int
+
+const (
+	IPv4 RouteType = 0
+	IPv6 RouteType = 1
+)
+
+type Route struct {
+	Type        RouteType
+	Default     bool
+	Device      string
+	Destination string
+	Gateway     string
+	Flags       string
+}

routing/tables.go

@@ -0,0 +1,39 @@
+package routing
+
+import "sync"
+
+var (
+	lock  = sync.RWMutex{}
+	table = make([]Route, 0)
+)
+
+func Table() []Route {
+	lock.RLock()
+	defer lock.RUnlock()
+	return table
+}
+
+func Update() ([]Route, error) {
+	lock.Lock()
+	defer lock.Unlock()
+	return update()
+}
+
+func Gateway(ip RouteType, device string) (string, error) {
+	Update()
+
+	lock.RLock()
+	defer lock.RUnlock()
+
+	for _, r := range table {
+		if r.Type == ip {
+			if device == "" || r.Device == device || r.Device == "" /* windows case */ {
+				if r.Default {
+					return r.Gateway, nil
+				}
+			}
+		}
+	}
+
+	return "", nil
+}

routing/update_darwin.go

@@ -0,0 +1,44 @@
+package routing
+
+import (
+	"github.com/bettercap/bettercap/core"
+	"github.com/evilsocket/islazy/str"
+	"regexp"
+	"strings"
+)
+
+var parser = regexp.MustCompile(`^([^\s]+)\s+([^\s]+)\s+([^\s]+)\s+([^\s]+).*$`)
+
+func update() ([]Route, error) {
+	table = make([]Route, 0)
+
+	output, err := core.Exec("netstat", []string{"-n", "-r"})
+	if err != nil {
+		return nil, err
+	}
+
+	for _, line := range strings.Split(output, "\n") {
+		if line = str.Trim(line); len(line) > 0 {
+			matches := parser.FindStringSubmatch(line)
+			if num := len(matches); num == 5 && matches[1] != "Destination" {
+				route := Route{
+					Destination: matches[1],
+					Gateway:     matches[2],
+					Flags:       matches[3],
+					Device:      matches[4],
+					Default:     matches[1] == "default",
+				}
+
+				if strings.ContainsRune(route.Destination, '.') || strings.ContainsRune(route.Gateway, '.') {
+					route.Type = IPv4
+				} else {
+					route.Type = IPv6
+				}
+
+				table = append(table, route)
+			}
+		}
+	}
+
+	return table, nil
+}

routing/update_linux.go

@@ -0,0 +1,45 @@
+package routing
+
+import (
+	"github.com/bettercap/bettercap/core"
+	"github.com/evilsocket/islazy/str"
+	"regexp"
+	"strings"
+)
+
+var parser = regexp.MustCompile(`^(.+)\sdev\s([^\s]+)\s(.+)$`)
+
+func update() ([]Route, error) {
+	table = make([]Route, 0)
+
+	for ip, inet := range map[RouteType]string{IPv4: "inet", IPv6: "inet6"} {
+		output, err := core.Exec("ip", []string{"-f", inet, "route"})
+		if err != nil {
+			return nil, err
+		}
+
+		for _, line := range strings.Split(output, "\n") {
+			if line = str.Trim(line); len(line) > 0 {
+				matches := parser.FindStringSubmatch(line)
+				if num := len(matches); num == 4 {
+					route := Route{
+						Type:        ip,
+						Destination: matches[1],
+						Device:      matches[2],
+						Flags:       matches[3],
+						Default:     strings.Index(matches[1], "default ") == 0,
+					}
+
+					if idx := strings.Index(route.Destination, " via "); idx >= 0 {
+						route.Gateway = route.Destination[idx + len(" via "):]
+						route.Destination = route.Destination[:idx]
+					}
+
+					table = append(table, route)
+				}
+			}
+		}
+	}
+
+	return table, nil
+}

routing/update_windows.go

@@ -0,0 +1,44 @@
+package routing
+
+import (
+	"github.com/bettercap/bettercap/core"
+	"github.com/evilsocket/islazy/str"
+	"regexp"
+	"strings"
+)
+
+var parser = regexp.MustCompile(`^.+\d+\s+([^\s]+)\s+\d+\s+(.+)$`)
+
+func update() ([]Route, error) {
+	table = make([]Route, 0)
+
+	for ip, inet := range map[RouteType]string{IPv4: "ipv4", IPv6: "ipv6"} {
+		output, err := core.Exec("netsh", []string{"interface", inet, "show", "route"})
+		if err != nil {
+			return nil, err
+		}
+
+		for _, line := range strings.Split(output, "\n") {
+			if line = str.Trim(line); len(line) > 0 {
+				matches := parser.FindStringSubmatch(line)
+				if num := len(matches); num == 3 {
+					route := Route{
+						Type:        ip,
+						Destination: matches[1],
+						Device:      matches[2],
+					}
+
+					if route.Destination == "0.0.0.0/0" || route.Destination == "::/0" {
+						route.Default = true
+						route.Gateway = route.Device
+						route.Device = ""
+					}
+
+					table = append(table, route)
+				}
+			}
+		}
+	}
+
+	return table, nil
+}