Add /proc/sys/net/ipv4/ip_forward

3 files changed, 28 insertions, 1 deletions

diff --git a/pkg/sentry/inet/BUILD b/pkg/sentry/inet/BUILD
index d5284f0d9..99481e05e 100644
--- a/pkg/sentry/inet/BUILD
+++ b/pkg/sentry/inet/BUILD
@@ -13,5 +13,8 @@ go_library(
         "test_stack.go",
     ],
     importpath = "gvisor.dev/gvisor/pkg/sentry/inet",
-    deps = ["//pkg/sentry/context"],
+    deps = [
+        "//pkg/sentry/context",
+        "//pkg/tcpip",
+    ],
 )
diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go
index bc6cb1095..6217100b2 100644
--- a/pkg/sentry/inet/inet.go
+++ b/pkg/sentry/inet/inet.go
@@ -15,6 +15,8 @@
 // Package inet defines semantics for IP stacks.
 package inet
 
+import "gvisor.dev/gvisor/pkg/tcpip"
+
 // Stack represents a TCP/IP stack.
 type Stack interface {
 	// Interfaces returns all network interfaces as a mapping from interface
@@ -58,6 +60,12 @@ type Stack interface {
 
 	// Resume restarts the network stack after restore.
 	Resume()
+
+	// Forwarding returns if packet forwarding between NICs is enabled.
+	Forwarding(protocol tcpip.NetworkProtocolNumber) bool
+
+	// SetForwarding enables or disables packet forwarding between NICs.
+	SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error
 }
 
 // Interface contains information about a network interface.
diff --git a/pkg/sentry/inet/test_stack.go b/pkg/sentry/inet/test_stack.go
index b9eed7c3a..c6907cfcb 100644
--- a/pkg/sentry/inet/test_stack.go
+++ b/pkg/sentry/inet/test_stack.go
@@ -14,6 +14,10 @@
 
 package inet
 
+import (
+	"gvisor.dev/gvisor/pkg/tcpip"
+)
+
 // TestStack is a dummy implementation of Stack for tests.
 type TestStack struct {
 	InterfacesMap     map[int32]Interface
@@ -23,6 +27,7 @@ type TestStack struct {
 	TCPRecvBufSize    TCPBufferSize
 	TCPSendBufSize    TCPBufferSize
 	TCPSACKFlag       bool
+	IPForwarding      bool
 }
 
 // NewTestStack returns a TestStack with no network interfaces. The value of
@@ -96,3 +101,14 @@ func (s *TestStack) RouteTable() []Route {
 // Resume implements Stack.Resume.
 func (s *TestStack) Resume() {
 }
+
+// Forwarding implements inet.Stack.Forwarding.
+func (s *TestStack) Forwarding(protocol tcpip.NetworkProtocolNumber) bool {
+	return s.IPForwarding
+}
+
+// SetForwarding implements inet.Stack.SetForwarding.
+func (s *TestStack) SetForwarding(protocol tcpip.NetworkProtocolNumber, enable bool) error {
+	s.IPForwarding = enable
+	return nil
+}