103 lines
3.0 KiB
Go
103 lines
3.0 KiB
Go
// Copyright 2020 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package inet
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// Namespace represents a network namespace. See network_namespaces(7).
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//
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// +stateify savable
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type Namespace struct {
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// stack is the network stack implementation of this network namespace.
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stack Stack `state:"nosave"`
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// creator allows kernel to create new network stack for network namespaces.
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// If nil, no networking will function if network is namespaced.
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//
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// At afterLoad(), creator will be used to create network stack. Stateify
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// needs to wait for this field to be loaded before calling afterLoad().
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creator NetworkStackCreator `state:"wait"`
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// isRoot indicates whether this is the root network namespace.
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isRoot bool
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}
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// NewRootNamespace creates the root network namespace, with creator
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// allowing new network namespaces to be created. If creator is nil, no
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// networking will function if the network is namespaced.
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func NewRootNamespace(stack Stack, creator NetworkStackCreator) *Namespace {
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return &Namespace{
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stack: stack,
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creator: creator,
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isRoot: true,
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}
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}
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// NewNamespace creates a new network namespace from the root.
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func NewNamespace(root *Namespace) *Namespace {
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n := &Namespace{
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creator: root.creator,
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}
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n.init()
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return n
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}
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// Stack returns the network stack of n. Stack may return nil if no network
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// stack is configured.
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func (n *Namespace) Stack() Stack {
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return n.stack
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}
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// IsRoot returns whether n is the root network namespace.
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func (n *Namespace) IsRoot() bool {
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return n.isRoot
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}
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// RestoreRootStack restores the root network namespace with stack. This should
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// only be called when restoring kernel.
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func (n *Namespace) RestoreRootStack(stack Stack) {
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if !n.isRoot {
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panic("RestoreRootStack can only be called on root network namespace")
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}
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if n.stack != nil {
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panic("RestoreRootStack called after a stack has already been set")
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}
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n.stack = stack
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}
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func (n *Namespace) init() {
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// Root network namespace will have stack assigned later.
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if n.isRoot {
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return
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}
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if n.creator != nil {
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var err error
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n.stack, err = n.creator.CreateStack()
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if err != nil {
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panic(err)
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}
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}
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}
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// afterLoad is invoked by stateify.
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func (n *Namespace) afterLoad() {
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n.init()
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}
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// NetworkStackCreator allows new instances of a network stack to be created. It
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// is used by the kernel to create new network namespaces when requested.
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type NetworkStackCreator interface {
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// CreateStack creates a new network stack for a network namespace.
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CreateStack() (Stack, error)
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}
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