145 lines
4.7 KiB
Go
145 lines
4.7 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 testutil defines types and functions used to test Network Layer
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// functionality such as IP fragmentation.
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package testutil
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import (
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"fmt"
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"math/rand"
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"gvisor.dev/gvisor/pkg/tcpip"
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"gvisor.dev/gvisor/pkg/tcpip/buffer"
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"gvisor.dev/gvisor/pkg/tcpip/header"
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"gvisor.dev/gvisor/pkg/tcpip/stack"
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)
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// MockLinkEndpoint is an endpoint used for testing, it stores packets written
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// to it and can mock errors.
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type MockLinkEndpoint struct {
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// WrittenPackets is where packets written to the endpoint are stored.
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WrittenPackets []*stack.PacketBuffer
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mtu uint32
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err *tcpip.Error
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allowPackets int
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}
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// NewMockLinkEndpoint creates a new MockLinkEndpoint.
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//
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// err is the error that will be returned once allowPackets packets are written
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// to the endpoint.
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func NewMockLinkEndpoint(mtu uint32, err *tcpip.Error, allowPackets int) *MockLinkEndpoint {
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return &MockLinkEndpoint{
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mtu: mtu,
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err: err,
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allowPackets: allowPackets,
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}
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}
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// MTU implements LinkEndpoint.MTU.
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func (ep *MockLinkEndpoint) MTU() uint32 { return ep.mtu }
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// Capabilities implements LinkEndpoint.Capabilities.
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func (*MockLinkEndpoint) Capabilities() stack.LinkEndpointCapabilities { return 0 }
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// MaxHeaderLength implements LinkEndpoint.MaxHeaderLength.
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func (*MockLinkEndpoint) MaxHeaderLength() uint16 { return 0 }
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// LinkAddress implements LinkEndpoint.LinkAddress.
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func (*MockLinkEndpoint) LinkAddress() tcpip.LinkAddress { return "" }
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// WritePacket implements LinkEndpoint.WritePacket.
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func (ep *MockLinkEndpoint) WritePacket(_ *stack.Route, _ *stack.GSO, _ tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
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if ep.allowPackets == 0 {
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return ep.err
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}
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ep.allowPackets--
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ep.WrittenPackets = append(ep.WrittenPackets, pkt)
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return nil
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}
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// WritePackets implements LinkEndpoint.WritePackets.
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func (ep *MockLinkEndpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.PacketBufferList, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
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var n int
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for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() {
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if err := ep.WritePacket(r, gso, protocol, pkt); err != nil {
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return n, err
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}
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n++
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}
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return n, nil
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}
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// WriteRawPacket implements LinkEndpoint.WriteRawPacket.
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func (ep *MockLinkEndpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error {
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if ep.allowPackets == 0 {
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return ep.err
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}
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ep.allowPackets--
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pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
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Data: vv,
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})
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ep.WrittenPackets = append(ep.WrittenPackets, pkt)
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return nil
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}
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// Attach implements LinkEndpoint.Attach.
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func (*MockLinkEndpoint) Attach(stack.NetworkDispatcher) {}
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// IsAttached implements LinkEndpoint.IsAttached.
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func (*MockLinkEndpoint) IsAttached() bool { return false }
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// Wait implements LinkEndpoint.Wait.
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func (*MockLinkEndpoint) Wait() {}
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// ARPHardwareType implements LinkEndpoint.ARPHardwareType.
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func (*MockLinkEndpoint) ARPHardwareType() header.ARPHardwareType { return header.ARPHardwareNone }
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// AddHeader implements LinkEndpoint.AddHeader.
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func (*MockLinkEndpoint) AddHeader(_, _ tcpip.LinkAddress, _ tcpip.NetworkProtocolNumber, _ *stack.PacketBuffer) {
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}
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// MakeRandPkt generates a randomized packet. transportHeaderLength indicates
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// how many random bytes will be copied in the Transport Header.
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// extraHeaderReserveLength indicates how much extra space will be reserved for
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// the other headers. The payload is made from Views of the sizes listed in
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// viewSizes.
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func MakeRandPkt(transportHeaderLength int, extraHeaderReserveLength int, viewSizes []int, proto tcpip.NetworkProtocolNumber) *stack.PacketBuffer {
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var views buffer.VectorisedView
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for _, s := range viewSizes {
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newView := buffer.NewView(s)
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if _, err := rand.Read(newView); err != nil {
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panic(fmt.Sprintf("rand.Read: %s", err))
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}
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views.AppendView(newView)
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}
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pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
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ReserveHeaderBytes: transportHeaderLength + extraHeaderReserveLength,
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Data: views,
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})
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pkt.NetworkProtocolNumber = proto
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if _, err := rand.Read(pkt.TransportHeader().Push(transportHeaderLength)); err != nil {
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panic(fmt.Sprintf("rand.Read: %s", err))
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}
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return pkt
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}
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