Implement dummy network interfacesfeature/dummy-iface

1 files changed, 24 insertions, 0 deletions

diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go
index 3fceb4cd5..360b270c1 100644
--- a/pkg/sentry/socket/netstack/stack.go
+++ b/pkg/sentry/socket/netstack/stack.go
@@ -24,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/link/dummy"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
@@ -71,6 +72,17 @@ func (s *Stack) Interfaces() map[int32]inet.Interface {
 	return is
 }
 
+func (s *Stack) AddDummyInterface(name string) (int32, error) {
+	var idx tcpip.NICID = s.nextInterfaceIndex()
+
+	dummyEP := dummy.New()
+	if err := s.Stack.CreateNICWithOptions(idx, dummyEP, stack.NICOptions{Name: name}); err != nil {
+		return -1, syserr.TranslateNetstackError(err).ToError()
+	}
+
+	return int32(idx), nil
+}
+
 // RemoveInterface implements inet.Stack.RemoveInterface.
 func (s *Stack) RemoveInterface(idx int32) error {
 	nic := tcpip.NICID(idx)
@@ -146,6 +158,18 @@ func convertAddr(addr inet.InterfaceAddr) (tcpip.ProtocolAddress, error) {
 	return protocolAddress, nil
 }
 
+func (s *Stack) nextInterfaceIndex() tcpip.NICID {
+	var maxIdx tcpip.NICID = 0
+
+	for id, _ := range s.Stack.NICInfo() {
+		if id > maxIdx {
+			maxIdx = id
+		}
+	}
+
+	return maxIdx + 1
+}
+
 // AddInterfaceAddr implements inet.Stack.AddInterfaceAddr.
 func (s *Stack) AddInterfaceAddr(idx int32, addr inet.InterfaceAddr) error {
 	protocolAddress, err := convertAddr(addr)