125 lines
4.1 KiB
Go
125 lines
4.1 KiB
Go
// Copyright 2018 Google LLC
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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 ping contains the implementation of the ICMP and IPv6-ICMP transport
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// protocols for use in ping. To use it in the networking stack, this package
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// must be added to the project, and
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// activated on the stack by passing ping.ProtocolName (or "ping") and/or
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// ping.ProtocolName6 (or "ping6") as one of the transport protocols when
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// calling stack.New(). Then endpoints can be created by passing
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// ping.ProtocolNumber or ping.ProtocolNumber6 as the transport protocol number
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// when calling Stack.NewEndpoint().
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package ping
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import (
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"encoding/binary"
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"fmt"
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"gvisor.googlesource.com/gvisor/pkg/tcpip"
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"gvisor.googlesource.com/gvisor/pkg/tcpip/buffer"
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"gvisor.googlesource.com/gvisor/pkg/tcpip/header"
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"gvisor.googlesource.com/gvisor/pkg/tcpip/stack"
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"gvisor.googlesource.com/gvisor/pkg/waiter"
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)
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const (
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// ProtocolName4 is the string representation of the ping protocol name.
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ProtocolName4 = "ping4"
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// ProtocolNumber4 is the ICMP protocol number.
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ProtocolNumber4 = header.ICMPv4ProtocolNumber
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// ProtocolName6 is the string representation of the ping protocol name.
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ProtocolName6 = "ping6"
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// ProtocolNumber6 is the IPv6-ICMP protocol number.
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ProtocolNumber6 = header.ICMPv6ProtocolNumber
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)
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type protocol struct {
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number tcpip.TransportProtocolNumber
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}
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// Number returns the ICMP protocol number.
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func (p *protocol) Number() tcpip.TransportProtocolNumber {
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return p.number
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}
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func (p *protocol) netProto() tcpip.NetworkProtocolNumber {
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switch p.number {
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case ProtocolNumber4:
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return header.IPv4ProtocolNumber
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case ProtocolNumber6:
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return header.IPv6ProtocolNumber
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}
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panic(fmt.Sprint("unknown protocol number: ", p.number))
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}
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// NewEndpoint creates a new ping endpoint.
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func (p *protocol) NewEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
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if netProto != p.netProto() {
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return nil, tcpip.ErrUnknownProtocol
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}
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return newEndpoint(stack, netProto, p.number, waiterQueue), nil
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}
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// MinimumPacketSize returns the minimum valid ping packet size.
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func (p *protocol) MinimumPacketSize() int {
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switch p.number {
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case ProtocolNumber4:
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return header.ICMPv4EchoMinimumSize
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case ProtocolNumber6:
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return header.ICMPv6EchoMinimumSize
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}
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panic(fmt.Sprint("unknown protocol number: ", p.number))
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}
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// ParsePorts returns the source and destination ports stored in the given ping
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// packet.
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func (p *protocol) ParsePorts(v buffer.View) (src, dst uint16, err *tcpip.Error) {
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switch p.number {
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case ProtocolNumber4:
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return 0, binary.BigEndian.Uint16(v[header.ICMPv4MinimumSize:]), nil
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case ProtocolNumber6:
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return 0, binary.BigEndian.Uint16(v[header.ICMPv6MinimumSize:]), nil
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}
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panic(fmt.Sprint("unknown protocol number: ", p.number))
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}
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// HandleUnknownDestinationPacket handles packets targeted at this protocol but
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// that don't match any existing endpoint.
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func (p *protocol) HandleUnknownDestinationPacket(*stack.Route, stack.TransportEndpointID, buffer.VectorisedView) bool {
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return true
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}
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// SetOption implements TransportProtocol.SetOption.
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func (p *protocol) SetOption(option interface{}) *tcpip.Error {
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return tcpip.ErrUnknownProtocolOption
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}
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// Option implements TransportProtocol.Option.
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func (p *protocol) Option(option interface{}) *tcpip.Error {
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return tcpip.ErrUnknownProtocolOption
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}
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func init() {
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stack.RegisterTransportProtocolFactory(ProtocolName4, func() stack.TransportProtocol {
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return &protocol{ProtocolNumber4}
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})
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stack.RegisterTransportProtocolFactory(ProtocolName6, func() stack.TransportProtocol {
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return &protocol{ProtocolNumber6}
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})
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}
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