Migrate clashtcpip to gVisor tcpip copied

internal/gtcpip/header/icmpv4.go

@@ -0,0 +1,228 @@
+// Copyright 2018 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 header
+
+import (
+	"encoding/binary"
+
+	"github.com/sagernet/sing-tun/internal/gtcpip"
+	"github.com/sagernet/sing-tun/internal/gtcpip/checksum"
+)
+
+// ICMPv4 represents an ICMPv4 header stored in a byte array.
+type ICMPv4 []byte
+
+const (
+	// ICMPv4PayloadOffset defines the start of ICMP payload.
+	ICMPv4PayloadOffset = 8
+
+	// ICMPv4MinimumSize is the minimum size of a valid ICMP packet.
+	ICMPv4MinimumSize = 8
+
+	// ICMPv4MinimumErrorPayloadSize Is the smallest number of bytes of an
+	// errant packet's transport layer that an ICMP error type packet should
+	// attempt to send as per RFC 792 (see each type) and RFC 1122
+	// section 3.2.2 which states:
+	//      Every ICMP error message includes the Internet header and at
+	//      least the first 8 data octets of the datagram that triggered
+	//      the error; more than 8 octets MAY be sent; this header and data
+	//      MUST be unchanged from the received datagram.
+	//
+	// RFC 792 shows:
+	//   0                   1                   2                   3
+	//  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+	// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	// |     Type      |     Code      |          Checksum             |
+	// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	// |                             unused                            |
+	// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	// |      Internet Header + 64 bits of Original Data Datagram      |
+	// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	ICMPv4MinimumErrorPayloadSize = 8
+
+	// ICMPv4ProtocolNumber is the ICMP transport protocol number.
+	ICMPv4ProtocolNumber tcpip.TransportProtocolNumber = 1
+
+	// icmpv4ChecksumOffset is the offset of the checksum field
+	// in an ICMPv4 message.
+	icmpv4ChecksumOffset = 2
+
+	// icmpv4MTUOffset is the offset of the MTU field
+	// in an ICMPv4FragmentationNeeded message.
+	icmpv4MTUOffset = 6
+
+	// icmpv4IdentOffset is the offset of the ident field
+	// in an ICMPv4EchoRequest/Reply message.
+	icmpv4IdentOffset = 4
+
+	// icmpv4PointerOffset is the offset of the pointer field
+	// in an ICMPv4ParamProblem message.
+	icmpv4PointerOffset = 4
+
+	// icmpv4SequenceOffset is the offset of the sequence field
+	// in an ICMPv4EchoRequest/Reply message.
+	icmpv4SequenceOffset = 6
+)
+
+// ICMPv4Type is the ICMP type field described in RFC 792.
+type ICMPv4Type byte
+
+// ICMPv4Code is the ICMP code field described in RFC 792.
+type ICMPv4Code byte
+
+// Typical values of ICMPv4Type defined in RFC 792.
+const (
+	ICMPv4EchoReply      ICMPv4Type = 0
+	ICMPv4DstUnreachable ICMPv4Type = 3
+	ICMPv4SrcQuench      ICMPv4Type = 4
+	ICMPv4Redirect       ICMPv4Type = 5
+	ICMPv4Echo           ICMPv4Type = 8
+	ICMPv4TimeExceeded   ICMPv4Type = 11
+	ICMPv4ParamProblem   ICMPv4Type = 12
+	ICMPv4Timestamp      ICMPv4Type = 13
+	ICMPv4TimestampReply ICMPv4Type = 14
+	ICMPv4InfoRequest    ICMPv4Type = 15
+	ICMPv4InfoReply      ICMPv4Type = 16
+)
+
+// ICMP codes for ICMPv4 Time Exceeded messages as defined in RFC 792.
+const (
+	ICMPv4TTLExceeded       ICMPv4Code = 0
+	ICMPv4ReassemblyTimeout ICMPv4Code = 1
+)
+
+// ICMP codes for ICMPv4 Destination Unreachable messages as defined in RFC 792,
+// RFC 1122 section 3.2.2.1 and RFC 1812 section 5.2.7.1.
+const (
+	ICMPv4NetUnreachable            ICMPv4Code = 0
+	ICMPv4HostUnreachable           ICMPv4Code = 1
+	ICMPv4ProtoUnreachable          ICMPv4Code = 2
+	ICMPv4PortUnreachable           ICMPv4Code = 3
+	ICMPv4FragmentationNeeded       ICMPv4Code = 4
+	ICMPv4SourceRouteFailed         ICMPv4Code = 5
+	ICMPv4DestinationNetworkUnknown ICMPv4Code = 6
+	ICMPv4DestinationHostUnknown    ICMPv4Code = 7
+	ICMPv4SourceHostIsolated        ICMPv4Code = 8
+	ICMPv4NetProhibited             ICMPv4Code = 9
+	ICMPv4HostProhibited            ICMPv4Code = 10
+	ICMPv4NetUnreachableForTos      ICMPv4Code = 11
+	ICMPv4HostUnreachableForTos     ICMPv4Code = 12
+	ICMPv4AdminProhibited           ICMPv4Code = 13
+	ICMPv4HostPrecedenceViolation   ICMPv4Code = 14
+	ICMPv4PrecedenceCutInEffect     ICMPv4Code = 15
+)
+
+// ICMPv4UnusedCode is a code to use in ICMP messages where no code is needed.
+const ICMPv4UnusedCode ICMPv4Code = 0
+
+// Type is the ICMP type field.
+func (b ICMPv4) Type() ICMPv4Type { return ICMPv4Type(b[0]) }
+
+// SetType sets the ICMP type field.
+func (b ICMPv4) SetType(t ICMPv4Type) { b[0] = byte(t) }
+
+// Code is the ICMP code field. Its meaning depends on the value of Type.
+func (b ICMPv4) Code() ICMPv4Code { return ICMPv4Code(b[1]) }
+
+// SetCode sets the ICMP code field.
+func (b ICMPv4) SetCode(c ICMPv4Code) { b[1] = byte(c) }
+
+// Pointer returns the pointer field in a Parameter Problem packet.
+func (b ICMPv4) Pointer() byte { return b[icmpv4PointerOffset] }
+
+// SetPointer sets the pointer field in a Parameter Problem packet.
+func (b ICMPv4) SetPointer(c byte) { b[icmpv4PointerOffset] = c }
+
+// Checksum is the ICMP checksum field.
+func (b ICMPv4) Checksum() uint16 {
+	return binary.BigEndian.Uint16(b[icmpv4ChecksumOffset:])
+}
+
+// SetChecksum sets the ICMP checksum field.
+func (b ICMPv4) SetChecksum(cs uint16) {
+	checksum.Put(b[icmpv4ChecksumOffset:], cs)
+}
+
+// SourcePort implements Transport.SourcePort.
+func (ICMPv4) SourcePort() uint16 {
+	return 0
+}
+
+// DestinationPort implements Transport.DestinationPort.
+func (ICMPv4) DestinationPort() uint16 {
+	return 0
+}
+
+// SetSourcePort implements Transport.SetSourcePort.
+func (ICMPv4) SetSourcePort(uint16) {
+}
+
+// SetDestinationPort implements Transport.SetDestinationPort.
+func (ICMPv4) SetDestinationPort(uint16) {
+}
+
+// Payload implements Transport.Payload.
+func (b ICMPv4) Payload() []byte {
+	return b[ICMPv4PayloadOffset:]
+}
+
+// MTU retrieves the MTU field from an ICMPv4 message.
+func (b ICMPv4) MTU() uint16 {
+	return binary.BigEndian.Uint16(b[icmpv4MTUOffset:])
+}
+
+// SetMTU sets the MTU field from an ICMPv4 message.
+func (b ICMPv4) SetMTU(mtu uint16) {
+	binary.BigEndian.PutUint16(b[icmpv4MTUOffset:], mtu)
+}
+
+// Ident retrieves the Ident field from an ICMPv4 message.
+func (b ICMPv4) Ident() uint16 {
+	return binary.BigEndian.Uint16(b[icmpv4IdentOffset:])
+}
+
+// SetIdent sets the Ident field from an ICMPv4 message.
+func (b ICMPv4) SetIdent(ident uint16) {
+	binary.BigEndian.PutUint16(b[icmpv4IdentOffset:], ident)
+}
+
+// SetIdentWithChecksumUpdate sets the Ident field and updates the checksum.
+func (b ICMPv4) SetIdentWithChecksumUpdate(new uint16) {
+	old := b.Ident()
+	b.SetIdent(new)
+	b.SetChecksum(^checksumUpdate2ByteAlignedUint16(^b.Checksum(), old, new))
+}
+
+// Sequence retrieves the Sequence field from an ICMPv4 message.
+func (b ICMPv4) Sequence() uint16 {
+	return binary.BigEndian.Uint16(b[icmpv4SequenceOffset:])
+}
+
+// SetSequence sets the Sequence field from an ICMPv4 message.
+func (b ICMPv4) SetSequence(sequence uint16) {
+	binary.BigEndian.PutUint16(b[icmpv4SequenceOffset:], sequence)
+}
+
+// ICMPv4Checksum calculates the ICMP checksum over the provided ICMP header,
+// and payload.
+func ICMPv4Checksum(h ICMPv4, payloadCsum uint16) uint16 {
+	xsum := payloadCsum
+
+	// h[2:4] is the checksum itself, skip it to avoid checksumming the checksum.
+	xsum = checksum.Checksum(h[:2], xsum)
+	xsum = checksum.Checksum(h[4:], xsum)
+
+	return ^xsum
+}