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-rw-r--r--pkg/tcpip/link/nested/BUILD31
-rw-r--r--pkg/tcpip/link/nested/nested.go131
-rw-r--r--pkg/tcpip/link/nested/nested_test.go105
3 files changed, 267 insertions, 0 deletions
diff --git a/pkg/tcpip/link/nested/BUILD b/pkg/tcpip/link/nested/BUILD
new file mode 100644
index 000000000..bdd5276ad
--- /dev/null
+++ b/pkg/tcpip/link/nested/BUILD
@@ -0,0 +1,31 @@
+load("//tools:defs.bzl", "go_library", "go_test")
+
+package(licenses = ["notice"])
+
+go_library(
+ name = "nested",
+ srcs = [
+ "nested.go",
+ ],
+ visibility = ["//visibility:public"],
+ deps = [
+ "//pkg/sync",
+ "//pkg/tcpip",
+ "//pkg/tcpip/buffer",
+ "//pkg/tcpip/stack",
+ ],
+)
+
+go_test(
+ name = "nested_test",
+ size = "small",
+ srcs = [
+ "nested_test.go",
+ ],
+ deps = [
+ "//pkg/tcpip",
+ "//pkg/tcpip/header",
+ "//pkg/tcpip/link/nested",
+ "//pkg/tcpip/stack",
+ ],
+)
diff --git a/pkg/tcpip/link/nested/nested.go b/pkg/tcpip/link/nested/nested.go
new file mode 100644
index 000000000..2998f9c4f
--- /dev/null
+++ b/pkg/tcpip/link/nested/nested.go
@@ -0,0 +1,131 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package nested provides helpers to implement the pattern of nested
+// stack.LinkEndpoints.
+package nested
+
+import (
+ "gvisor.dev/gvisor/pkg/sync"
+ "gvisor.dev/gvisor/pkg/tcpip"
+ "gvisor.dev/gvisor/pkg/tcpip/buffer"
+ "gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+// Endpoint is a wrapper around stack.LinkEndpoint and stack.NetworkDispatcher
+// that can be used to implement nesting safely by providing lifecycle
+// concurrency guards.
+//
+// See the tests in this package for example usage.
+type Endpoint struct {
+ child stack.LinkEndpoint
+ embedder stack.NetworkDispatcher
+
+ // mu protects dispatcher.
+ mu sync.RWMutex
+ dispatcher stack.NetworkDispatcher
+}
+
+var _ stack.GSOEndpoint = (*Endpoint)(nil)
+var _ stack.LinkEndpoint = (*Endpoint)(nil)
+var _ stack.NetworkDispatcher = (*Endpoint)(nil)
+
+// Init initializes a nested.Endpoint that uses embedder as the dispatcher for
+// child on Attach.
+//
+// See the tests in this package for example usage.
+func (e *Endpoint) Init(child stack.LinkEndpoint, embedder stack.NetworkDispatcher) {
+ e.child = child
+ e.embedder = embedder
+}
+
+// DeliverNetworkPacket implements stack.NetworkDispatcher.
+func (e *Endpoint) DeliverNetworkPacket(remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
+ e.mu.RLock()
+ d := e.dispatcher
+ e.mu.RUnlock()
+ if d != nil {
+ d.DeliverNetworkPacket(remote, local, protocol, pkt)
+ }
+}
+
+// Attach implements stack.LinkEndpoint.
+func (e *Endpoint) Attach(dispatcher stack.NetworkDispatcher) {
+ e.mu.Lock()
+ e.dispatcher = dispatcher
+ e.mu.Unlock()
+ // If we're attaching to a valid dispatcher, pass embedder as the dispatcher
+ // to our child, otherwise detach the child by giving it a nil dispatcher.
+ var pass stack.NetworkDispatcher
+ if dispatcher != nil {
+ pass = e.embedder
+ }
+ e.child.Attach(pass)
+}
+
+// IsAttached implements stack.LinkEndpoint.
+func (e *Endpoint) IsAttached() bool {
+ e.mu.RLock()
+ isAttached := e.dispatcher != nil
+ e.mu.RUnlock()
+ return isAttached
+}
+
+// MTU implements stack.LinkEndpoint.
+func (e *Endpoint) MTU() uint32 {
+ return e.child.MTU()
+}
+
+// Capabilities implements stack.LinkEndpoint.
+func (e *Endpoint) Capabilities() stack.LinkEndpointCapabilities {
+ return e.child.Capabilities()
+}
+
+// MaxHeaderLength implements stack.LinkEndpoint.
+func (e *Endpoint) MaxHeaderLength() uint16 {
+ return e.child.MaxHeaderLength()
+}
+
+// LinkAddress implements stack.LinkEndpoint.
+func (e *Endpoint) LinkAddress() tcpip.LinkAddress {
+ return e.child.LinkAddress()
+}
+
+// WritePacket implements stack.LinkEndpoint.
+func (e *Endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
+ return e.child.WritePacket(r, gso, protocol, pkt)
+}
+
+// WritePackets implements stack.LinkEndpoint.
+func (e *Endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.PacketBufferList, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
+ return e.child.WritePackets(r, gso, pkts, protocol)
+}
+
+// WriteRawPacket implements stack.LinkEndpoint.
+func (e *Endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error {
+ return e.child.WriteRawPacket(vv)
+}
+
+// Wait implements stack.LinkEndpoint.
+func (e *Endpoint) Wait() {
+ e.child.Wait()
+}
+
+// GSOMaxSize implements stack.GSOEndpoint.
+func (e *Endpoint) GSOMaxSize() uint32 {
+ if e, ok := e.child.(stack.GSOEndpoint); ok {
+ return e.GSOMaxSize()
+ }
+ return 0
+}
diff --git a/pkg/tcpip/link/nested/nested_test.go b/pkg/tcpip/link/nested/nested_test.go
new file mode 100644
index 000000000..c1a219f02
--- /dev/null
+++ b/pkg/tcpip/link/nested/nested_test.go
@@ -0,0 +1,105 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package nested_test
+
+import (
+ "testing"
+
+ "gvisor.dev/gvisor/pkg/tcpip"
+ "gvisor.dev/gvisor/pkg/tcpip/header"
+ "gvisor.dev/gvisor/pkg/tcpip/link/nested"
+ "gvisor.dev/gvisor/pkg/tcpip/stack"
+)
+
+type parentEndpoint struct {
+ nested.Endpoint
+}
+
+var _ stack.LinkEndpoint = (*parentEndpoint)(nil)
+var _ stack.NetworkDispatcher = (*parentEndpoint)(nil)
+
+type childEndpoint struct {
+ stack.LinkEndpoint
+ dispatcher stack.NetworkDispatcher
+}
+
+var _ stack.LinkEndpoint = (*childEndpoint)(nil)
+
+func (c *childEndpoint) Attach(dispatcher stack.NetworkDispatcher) {
+ c.dispatcher = dispatcher
+}
+
+func (c *childEndpoint) IsAttached() bool {
+ return c.dispatcher != nil
+}
+
+type counterDispatcher struct {
+ count int
+}
+
+var _ stack.NetworkDispatcher = (*counterDispatcher)(nil)
+
+func (d *counterDispatcher) DeliverNetworkPacket(tcpip.LinkAddress, tcpip.LinkAddress, tcpip.NetworkProtocolNumber, *stack.PacketBuffer) {
+ d.count++
+}
+
+func TestNestedLinkEndpoint(t *testing.T) {
+ const emptyAddress = tcpip.LinkAddress("")
+
+ var (
+ childEP childEndpoint
+ nestedEP parentEndpoint
+ disp counterDispatcher
+ )
+ nestedEP.Endpoint.Init(&childEP, &nestedEP)
+
+ if childEP.IsAttached() {
+ t.Error("On init, childEP.IsAttached() = true, want = false")
+ }
+ if nestedEP.IsAttached() {
+ t.Error("On init, nestedEP.IsAttached() = true, want = false")
+ }
+
+ nestedEP.Attach(&disp)
+ if disp.count != 0 {
+ t.Fatalf("After attach, got disp.count = %d, want = 0", disp.count)
+ }
+ if !childEP.IsAttached() {
+ t.Error("After attach, childEP.IsAttached() = false, want = true")
+ }
+ if !nestedEP.IsAttached() {
+ t.Error("After attach, nestedEP.IsAttached() = false, want = true")
+ }
+
+ nestedEP.DeliverNetworkPacket(emptyAddress, emptyAddress, header.IPv4ProtocolNumber, &stack.PacketBuffer{})
+ if disp.count != 1 {
+ t.Errorf("After first packet with dispatcher attached, got disp.count = %d, want = 1", disp.count)
+ }
+
+ nestedEP.Attach(nil)
+ if childEP.IsAttached() {
+ t.Error("After detach, childEP.IsAttached() = true, want = false")
+ }
+ if nestedEP.IsAttached() {
+ t.Error("After detach, nestedEP.IsAttached() = true, want = false")
+ }
+
+ disp.count = 0
+ nestedEP.DeliverNetworkPacket(emptyAddress, emptyAddress, header.IPv4ProtocolNumber, &stack.PacketBuffer{})
+ if disp.count != 0 {
+ t.Errorf("After second packet with dispatcher detached, got disp.count = %d, want = 0", disp.count)
+ }
+
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 22:54:44 +0000