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

8 files changed, 68 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) {}
diff --git a/pkg/sentry/socket/hostinet/BUILD b/pkg/sentry/socket/hostinet/BUILD
index 4d174dda4..8b66a719d 100644
--- a/pkg/sentry/socket/hostinet/BUILD
+++ b/pkg/sentry/socket/hostinet/BUILD
@@ -32,6 +32,7 @@ go_library(
         "//pkg/sentry/usermem",
         "//pkg/syserr",
         "//pkg/syserror",
+        "//pkg/tcpip/stack",
         "//pkg/waiter",
     ],
 )
diff --git a/pkg/sentry/socket/hostinet/stack.go b/pkg/sentry/socket/hostinet/stack.go
index d4387f5d4..e67b46c9e 100644
--- a/pkg/sentry/socket/hostinet/stack.go
+++ b/pkg/sentry/socket/hostinet/stack.go
@@ -31,6 +31,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
 var defaultRecvBufSize = inet.TCPBufferSize{
@@ -442,3 +443,12 @@ func (s *Stack) RouteTable() []inet.Route {
 
 // Resume implements inet.Stack.Resume.
 func (s *Stack) Resume() {}
+
+// RegisteredEndpoints implements inet.Stack.RegisteredEndpoints.
+func (s *Stack) RegisteredEndpoints() []stack.TransportEndpoint { return nil }
+
+// CleanupEndpoints implements inet.Stack.CleanupEndpoints.
+func (s *Stack) CleanupEndpoints() []stack.TransportEndpoint { return nil }
+
+// RestoreCleanupEndpoints implements inet.Stack.RestoreCleanupEndpoints.
+func (s *Stack) RestoreCleanupEndpoints([]stack.TransportEndpoint) {}
diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go
index d5db8c17c..a0db2d4fd 100644
--- a/pkg/sentry/socket/netstack/stack.go
+++ b/pkg/sentry/socket/netstack/stack.go
@@ -291,3 +291,18 @@ func (s *Stack) FillDefaultIPTables() {
 func (s *Stack) Resume() {
 	s.Stack.Resume()
 }
+
+// RegisteredEndpoints implements inet.Stack.RegisteredEndpoints.
+func (s *Stack) RegisteredEndpoints() []stack.TransportEndpoint {
+	return s.Stack.RegisteredEndpoints()
+}
+
+// CleanupEndpoints implements inet.Stack.CleanupEndpoints.
+func (s *Stack) CleanupEndpoints() []stack.TransportEndpoint {
+	return s.Stack.CleanupEndpoints()
+}
+
+// RestoreCleanupEndpoints implements inet.Stack.RestoreCleanupEndpoints.
+func (s *Stack) RestoreCleanupEndpoints(es []stack.TransportEndpoint) {
+	s.Stack.RestoreCleanupEndpoints(es)
+}
diff --git a/pkg/sentry/socket/rpcinet/BUILD b/pkg/sentry/socket/rpcinet/BUILD
index 3a6baa308..4668b87d1 100644
--- a/pkg/sentry/socket/rpcinet/BUILD
+++ b/pkg/sentry/socket/rpcinet/BUILD
@@ -37,6 +37,7 @@ go_library(
         "//pkg/syserror",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
+        "//pkg/tcpip/stack",
         "//pkg/unet",
         "//pkg/waiter",
     ],
diff --git a/pkg/sentry/socket/rpcinet/stack.go b/pkg/sentry/socket/rpcinet/stack.go
index 5dcb6b455..f7878a760 100644
--- a/pkg/sentry/socket/rpcinet/stack.go
+++ b/pkg/sentry/socket/rpcinet/stack.go
@@ -23,6 +23,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/conn"
 	"gvisor.dev/gvisor/pkg/sentry/socket/rpcinet/notifier"
 	"gvisor.dev/gvisor/pkg/syserr"
+	"gvisor.dev/gvisor/pkg/tcpip/stack"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
@@ -165,3 +166,12 @@ func (s *Stack) RouteTable() []inet.Route {
 
 // Resume implements inet.Stack.Resume.
 func (s *Stack) Resume() {}
+
+// RegisteredEndpoints implements inet.Stack.RegisteredEndpoints.
+func (s *Stack) RegisteredEndpoints() []stack.TransportEndpoint { return nil }
+
+// CleanupEndpoints implements inet.Stack.CleanupEndpoints.
+func (s *Stack) CleanupEndpoints() []stack.TransportEndpoint { return nil }
+
+// RestoreCleanupEndpoints implements inet.Stack.RestoreCleanupEndpoints.
+func (s *Stack) RestoreCleanupEndpoints([]stack.TransportEndpoint) {}