5 files changed, 38 insertions, 7 deletions
diff --git a/test/packetimpact/testbench/BUILD b/test/packetimpact/testbench/BUILD
index fed51006f..d588d3289 100644
--- a/test/packetimpact/testbench/BUILD
+++ b/test/packetimpact/testbench/BUILD
@@ -21,6 +21,7 @@ go_library(
         "//pkg/tcpip/header",
         "//pkg/tcpip/seqnum",
         "//pkg/usermem",
+        "//test/packetimpact/netdevs",
         "//test/packetimpact/proto:posix_server_go_proto",
         "@com_github_google_go-cmp//cmp:go_default_library",
         "@com_github_google_go-cmp//cmp/cmpopts:go_default_library",
diff --git a/test/packetimpact/testbench/connections.go b/test/packetimpact/testbench/connections.go
index 463fd0556..bf104e5ca 100644
--- a/test/packetimpact/testbench/connections.go
+++ b/test/packetimpact/testbench/connections.go
@@ -114,12 +114,12 @@ var _ layerState = (*etherState)(nil)
 func newEtherState(out, in Ether) (*etherState, error) {
 	lMAC, err := tcpip.ParseMACAddress(LocalMAC)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("parsing local MAC: %q: %w", LocalMAC, err)
 	}
 
 	rMAC, err := tcpip.ParseMACAddress(RemoteMAC)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("parsing remote MAC: %q: %w", RemoteMAC, err)
 	}
 	s := etherState{
 		out: Ether{SrcAddr: &lMAC, DstAddr: &rMAC},
diff --git a/test/packetimpact/testbench/dut.go b/test/packetimpact/testbench/dut.go
index a78b7d7ee..b919a3c2e 100644
--- a/test/packetimpact/testbench/dut.go
+++ b/test/packetimpact/testbench/dut.go
@@ -16,6 +16,7 @@ package testbench
 
 import (
 	"context"
+	"flag"
 	"net"
 	"strconv"
 	"syscall"
@@ -37,6 +38,11 @@ type DUT struct {
 
 // NewDUT creates a new connection with the DUT over gRPC.
 func NewDUT(t *testing.T) DUT {
+	flag.Parse()
+	if err := genPseudoFlags(); err != nil {
+		t.Fatal("generating psuedo flags:", err)
+	}
+
 	posixServerAddress := POSIXServerIP + ":" + strconv.Itoa(POSIXServerPort)
 	conn, err := grpc.Dial(posixServerAddress, grpc.WithInsecure(), grpc.WithKeepaliveParams(keepalive.ClientParameters{Timeout: RPCKeepalive}))
 	if err != nil {
diff --git a/test/packetimpact/testbench/rawsockets.go b/test/packetimpact/testbench/rawsockets.go
index 4665f60b2..278229b7e 100644
--- a/test/packetimpact/testbench/rawsockets.go
+++ b/test/packetimpact/testbench/rawsockets.go
@@ -16,7 +16,6 @@ package testbench
 
 import (
 	"encoding/binary"
-	"flag"
 	"fmt"
 	"math"
 	"net"
@@ -41,7 +40,6 @@ func htons(x uint16) uint16 {
 
 // NewSniffer creates a Sniffer connected to *device.
 func NewSniffer(t *testing.T) (Sniffer, error) {
-	flag.Parse()
 	snifferFd, err := unix.Socket(unix.AF_PACKET, unix.SOCK_RAW, int(htons(unix.ETH_P_ALL)))
 	if err != nil {
 		return Sniffer{}, err
@@ -136,7 +134,6 @@ type Injector struct {
 
 // NewInjector creates a new injector on *device.
 func NewInjector(t *testing.T) (Injector, error) {
-	flag.Parse()
 	ifInfo, err := net.InterfaceByName(Device)
 	if err != nil {
 		return Injector{}, err
diff --git a/test/packetimpact/testbench/testbench.go b/test/packetimpact/testbench/testbench.go
index a1242b189..4de2aa1d3 100644
--- a/test/packetimpact/testbench/testbench.go
+++ b/test/packetimpact/testbench/testbench.go
@@ -16,7 +16,12 @@ package testbench
 
 import (
 	"flag"
+	"fmt"
+	"net"
+	"os/exec"
 	"time"
+
+	"gvisor.dev/gvisor/test/packetimpact/netdevs"
 )
 
 var (
@@ -55,9 +60,31 @@ func RegisterFlags(fs *flag.FlagSet) {
 	fs.DurationVar(&RPCKeepalive, "rpc_keepalive", RPCKeepalive, "gRPC keepalive")
 	fs.StringVar(&LocalIPv4, "local_ipv4", LocalIPv4, "local IPv4 address for test packets")
 	fs.StringVar(&RemoteIPv4, "remote_ipv4", RemoteIPv4, "remote IPv4 address for test packets")
-	fs.StringVar(&LocalIPv6, "local_ipv6", LocalIPv6, "local IPv6 address for test packets")
 	fs.StringVar(&RemoteIPv6, "remote_ipv6", RemoteIPv6, "remote IPv6 address for test packets")
-	fs.StringVar(&LocalMAC, "local_mac", LocalMAC, "local mac address for test packets")
 	fs.StringVar(&RemoteMAC, "remote_mac", RemoteMAC, "remote mac address for test packets")
 	fs.StringVar(&Device, "device", Device, "local device for test packets")
 }
+
+// genPseudoFlags populates flag-like global config based on real flags.
+//
+// genPseudoFlags must only be called after flag.Parse.
+func genPseudoFlags() error {
+	out, err := exec.Command("ip", "addr", "show").CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("listing devices: %q: %w", string(out), err)
+	}
+	devs, err := netdevs.ParseDevices(string(out))
+	if err != nil {
+		return fmt.Errorf("parsing devices: %w", err)
+	}
+
+	_, deviceInfo, err := netdevs.FindDeviceByIP(net.ParseIP(LocalIPv4), devs)
+	if err != nil {
+		return fmt.Errorf("can't find deviceInfo: %w", err)
+	}
+
+	LocalMAC = deviceInfo.MAC.String()
+	LocalIPv6 = deviceInfo.IPv6Addr.String()
+
+	return nil
+}