| // 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/google/netstack/tcpip" |
| "github.com/google/netstack/tcpip/buffer" |
| ) |
| |
| // ICMPv6 represents an ICMPv6 header stored in a byte array. |
| type ICMPv6 []byte |
| |
| const ( |
| // ICMPv6HeaderSize is the size of the ICMPv6 header. That is, the |
| // sum of the size of the ICMPv6 Type, Code and Checksum fields, as |
| // per RFC 4443 section 2.1. After the ICMPv6 header, the ICMPv6 |
| // message body begins. |
| ICMPv6HeaderSize = 4 |
| |
| // ICMPv6MinimumSize is the minimum size of a valid ICMP packet. |
| ICMPv6MinimumSize = 8 |
| |
| // ICMPv6PayloadOffset is the offset of the payload in an |
| // ICMP packet. |
| ICMPv6PayloadOffset = 8 |
| |
| // ICMPv6ProtocolNumber is the ICMP transport protocol number. |
| ICMPv6ProtocolNumber tcpip.TransportProtocolNumber = 58 |
| |
| // ICMPv6NeighborSolicitMinimumSize is the minimum size of a |
| // neighbor solicitation packet. |
| ICMPv6NeighborSolicitMinimumSize = ICMPv6HeaderSize + NDPNSMinimumSize |
| |
| // ICMPv6NeighborAdvertMinimumSize is the minimum size of a |
| // neighbor advertisement packet. |
| ICMPv6NeighborAdvertMinimumSize = ICMPv6HeaderSize + NDPNAMinimumSize |
| |
| // ICMPv6NeighborAdvertSize is size of a neighbor advertisement |
| // including the NDP Target Link Layer option for an Ethernet |
| // address. |
| ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + ndpTargetEthernetLinkLayerAddressSize |
| |
| // ICMPv6EchoMinimumSize is the minimum size of a valid ICMP echo packet. |
| ICMPv6EchoMinimumSize = 8 |
| |
| // ICMPv6DstUnreachableMinimumSize is the minimum size of a valid ICMP |
| // destination unreachable packet. |
| ICMPv6DstUnreachableMinimumSize = ICMPv6MinimumSize |
| |
| // ICMPv6PacketTooBigMinimumSize is the minimum size of a valid ICMP |
| // packet-too-big packet. |
| ICMPv6PacketTooBigMinimumSize = ICMPv6MinimumSize |
| |
| // icmpv6ChecksumOffset is the offset of the checksum field |
| // in an ICMPv6 message. |
| icmpv6ChecksumOffset = 2 |
| |
| // icmpv6MTUOffset is the offset of the MTU field in an ICMPv6 |
| // PacketTooBig message. |
| icmpv6MTUOffset = 4 |
| |
| // icmpv6IdentOffset is the offset of the ident field |
| // in a ICMPv6 Echo Request/Reply message. |
| icmpv6IdentOffset = 4 |
| |
| // icmpv6SequenceOffset is the offset of the sequence field |
| // in a ICMPv6 Echo Request/Reply message. |
| icmpv6SequenceOffset = 6 |
| |
| // NDPHopLimit is the expected IP hop limit value of 255 for received |
| // NDP packets, as per RFC 4861 sections 4.1 - 4.5, 6.1.1, 6.1.2, 7.1.1, |
| // 7.1.2 and 8.1. If the hop limit value is not 255, nodes MUST silently |
| // drop the NDP packet. All outgoing NDP packets must use this value for |
| // its IP hop limit field. |
| NDPHopLimit = 255 |
| ) |
| |
| // ICMPv6Type is the ICMP type field described in RFC 4443 and friends. |
| type ICMPv6Type byte |
| |
| // Typical values of ICMPv6Type defined in RFC 4443. |
| const ( |
| ICMPv6DstUnreachable ICMPv6Type = 1 |
| ICMPv6PacketTooBig ICMPv6Type = 2 |
| ICMPv6TimeExceeded ICMPv6Type = 3 |
| ICMPv6ParamProblem ICMPv6Type = 4 |
| ICMPv6EchoRequest ICMPv6Type = 128 |
| ICMPv6EchoReply ICMPv6Type = 129 |
| |
| // Neighbor Discovery Protocol (NDP) messages, see RFC 4861. |
| |
| ICMPv6RouterSolicit ICMPv6Type = 133 |
| ICMPv6RouterAdvert ICMPv6Type = 134 |
| ICMPv6NeighborSolicit ICMPv6Type = 135 |
| ICMPv6NeighborAdvert ICMPv6Type = 136 |
| ICMPv6RedirectMsg ICMPv6Type = 137 |
| ) |
| |
| // Values for ICMP code as defined in RFC 4443. |
| const ( |
| ICMPv6PortUnreachable = 4 |
| ) |
| |
| // Type is the ICMP type field. |
| func (b ICMPv6) Type() ICMPv6Type { return ICMPv6Type(b[0]) } |
| |
| // SetType sets the ICMP type field. |
| func (b ICMPv6) SetType(t ICMPv6Type) { b[0] = byte(t) } |
| |
| // Code is the ICMP code field. Its meaning depends on the value of Type. |
| func (b ICMPv6) Code() byte { return b[1] } |
| |
| // SetCode sets the ICMP code field. |
| func (b ICMPv6) SetCode(c byte) { b[1] = c } |
| |
| // Checksum is the ICMP checksum field. |
| func (b ICMPv6) Checksum() uint16 { |
| return binary.BigEndian.Uint16(b[icmpv6ChecksumOffset:]) |
| } |
| |
| // SetChecksum calculates and sets the ICMP checksum field. |
| func (b ICMPv6) SetChecksum(checksum uint16) { |
| binary.BigEndian.PutUint16(b[icmpv6ChecksumOffset:], checksum) |
| } |
| |
| // SourcePort implements Transport.SourcePort. |
| func (ICMPv6) SourcePort() uint16 { |
| return 0 |
| } |
| |
| // DestinationPort implements Transport.DestinationPort. |
| func (ICMPv6) DestinationPort() uint16 { |
| return 0 |
| } |
| |
| // SetSourcePort implements Transport.SetSourcePort. |
| func (ICMPv6) SetSourcePort(uint16) { |
| } |
| |
| // SetDestinationPort implements Transport.SetDestinationPort. |
| func (ICMPv6) SetDestinationPort(uint16) { |
| } |
| |
| // MTU retrieves the MTU field from an ICMPv6 message. |
| func (b ICMPv6) MTU() uint32 { |
| return binary.BigEndian.Uint32(b[icmpv6MTUOffset:]) |
| } |
| |
| // SetMTU sets the MTU field from an ICMPv6 message. |
| func (b ICMPv6) SetMTU(mtu uint32) { |
| binary.BigEndian.PutUint32(b[icmpv6MTUOffset:], mtu) |
| } |
| |
| // Ident retrieves the Ident field from an ICMPv6 message. |
| func (b ICMPv6) Ident() uint16 { |
| return binary.BigEndian.Uint16(b[icmpv6IdentOffset:]) |
| } |
| |
| // SetIdent sets the Ident field from an ICMPv6 message. |
| func (b ICMPv6) SetIdent(ident uint16) { |
| binary.BigEndian.PutUint16(b[icmpv6IdentOffset:], ident) |
| } |
| |
| // Sequence retrieves the Sequence field from an ICMPv6 message. |
| func (b ICMPv6) Sequence() uint16 { |
| return binary.BigEndian.Uint16(b[icmpv6SequenceOffset:]) |
| } |
| |
| // SetSequence sets the Sequence field from an ICMPv6 message. |
| func (b ICMPv6) SetSequence(sequence uint16) { |
| binary.BigEndian.PutUint16(b[icmpv6SequenceOffset:], sequence) |
| } |
| |
| // NDPPayload returns the NDP payload buffer. That is, it returns the ICMPv6 |
| // packet's message body as defined by RFC 4443 section 2.1; the portion of the |
| // ICMPv6 buffer after the first ICMPv6HeaderSize bytes. |
| func (b ICMPv6) NDPPayload() []byte { |
| return b[ICMPv6HeaderSize:] |
| } |
| |
| // Payload implements Transport.Payload. |
| func (b ICMPv6) Payload() []byte { |
| return b[ICMPv6PayloadOffset:] |
| } |
| |
| // ICMPv6Checksum calculates the ICMP checksum over the provided ICMP header, |
| // IPv6 src/dst addresses and the payload. |
| func ICMPv6Checksum(h ICMPv6, src, dst tcpip.Address, vv buffer.VectorisedView) uint16 { |
| // Calculate the IPv6 pseudo-header upper-layer checksum. |
| xsum := Checksum([]byte(src), 0) |
| xsum = Checksum([]byte(dst), xsum) |
| var upperLayerLength [4]byte |
| binary.BigEndian.PutUint32(upperLayerLength[:], uint32(len(h)+vv.Size())) |
| xsum = Checksum(upperLayerLength[:], xsum) |
| xsum = Checksum([]byte{0, 0, 0, uint8(ICMPv6ProtocolNumber)}, xsum) |
| for _, v := range vv.Views() { |
| xsum = Checksum(v, xsum) |
| } |
| |
| // h[2:4] is the checksum itself, set it aside to avoid checksumming the checksum. |
| h2, h3 := h[2], h[3] |
| h[2], h[3] = 0, 0 |
| xsum = ^Checksum(h, xsum) |
| h[2], h[3] = h2, h3 |
| |
| return xsum |
| } |