Add endpoint tracking to the stack.

In the future this will replace DanglingEndpoints. DanglingEndpoints must be
kept for now due to issues with save/restore.

This is arguably a cleaner design and allows the stack to know which transport
endpoints might still be using its link endpoints.

Updates #837

PiperOrigin-RevId: 277386633

3 files changed, 31 insertions, 2 deletions

diff --git a/pkg/sentry/inet/BUILD b/pkg/sentry/inet/BUILD
index d5284f0d9..8d60ad4ad 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/stack",
+    ],
 )
diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go
index bc6cb1095..a7dfb78a7 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"
+
 // Stack represents a TCP/IP stack.
 type Stack interface {
 	// Interfaces returns all network interfaces as a mapping from interface
@@ -58,6 +60,16 @@ type Stack interface {
 
 	// Resume restarts the network stack after restore.
 	Resume()
+
+	// RegisteredEndpoints returns all endpoints which are currently registered.
+	RegisteredEndpoints() []stack.TransportEndpoint
+
+	// CleanupEndpoints returns endpoints currently in the cleanup state.
+	CleanupEndpoints() []stack.TransportEndpoint
+
+	// RestoreCleanupEndpoints adds endpoints to cleanup tracking. This is useful
+	// for restoring a stack after a save.
+	RestoreCleanupEndpoints([]stack.TransportEndpoint)
 }
 
 // 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..dcfcbd97e 100644
--- a/pkg/sentry/inet/test_stack.go
+++ b/pkg/sentry/inet/test_stack.go
@@ -14,6 +14,8 @@
 
 package inet
 
+import "gvisor.dev/gvisor/pkg/tcpip/stack"
+
 // TestStack is a dummy implementation of Stack for tests.
 type TestStack struct {
 	InterfacesMap     map[int32]Interface
@@ -94,5 +96,17 @@ func (s *TestStack) RouteTable() []Route {
 }
 
 // Resume implements Stack.Resume.
-func (s *TestStack) Resume() {
+func (s *TestStack) Resume() {}
+
+// RegisteredEndpoints implements inet.Stack.RegisteredEndpoints.
+func (s *TestStack) RegisteredEndpoints() []stack.TransportEndpoint {
+	return nil
 }
+
+// CleanupEndpoints implements inet.Stack.CleanupEndpoints.
+func (s *TestStack) CleanupEndpoints() []stack.TransportEndpoint {
+	return nil
+}
+
+// RestoreCleanupEndpoints implements inet.Stack.RestoreCleanupEndpoints.
+func (s *TestStack) RestoreCleanupEndpoints([]stack.TransportEndpoint) {}