diff options
Diffstat (limited to 'pkg/tcpip/header')
-rw-r--r-- | pkg/tcpip/header/BUILD | 5 | ||||
-rw-r--r-- | pkg/tcpip/header/icmpv4.go | 71 | ||||
-rw-r--r-- | pkg/tcpip/header/icmpv6.go | 88 | ||||
-rw-r--r-- | pkg/tcpip/header/ipv4.go | 35 | ||||
-rw-r--r-- | pkg/tcpip/header/ipv6.go | 55 | ||||
-rw-r--r-- | pkg/tcpip/header/udp.go | 5 |
6 files changed, 219 insertions, 40 deletions
diff --git a/pkg/tcpip/header/BUILD b/pkg/tcpip/header/BUILD index 76ef02f13..a255231a3 100644 --- a/pkg/tcpip/header/BUILD +++ b/pkg/tcpip/header/BUILD @@ -1,6 +1,7 @@ -package(licenses = ["notice"]) +load("@io_bazel_rules_go//go:def.bzl", "go_test") +load("//tools/go_stateify:defs.bzl", "go_library") -load("//tools/go_stateify:defs.bzl", "go_library", "go_test") +package(licenses = ["notice"]) go_library( name = "header", diff --git a/pkg/tcpip/header/icmpv4.go b/pkg/tcpip/header/icmpv4.go index c52c0d851..0cac6c0a5 100644 --- a/pkg/tcpip/header/icmpv4.go +++ b/pkg/tcpip/header/icmpv4.go @@ -18,6 +18,7 @@ import ( "encoding/binary" "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/buffer" ) // ICMPv4 represents an ICMPv4 header stored in a byte array. @@ -25,13 +26,29 @@ type ICMPv4 []byte const ( // ICMPv4PayloadOffset defines the start of ICMP payload. - ICMPv4PayloadOffset = 4 + ICMPv4PayloadOffset = 8 // ICMPv4MinimumSize is the minimum size of a valid ICMP packet. ICMPv4MinimumSize = 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 a ICMPv4FragmentationNeeded message. + icmpv4MTUOffset = 6 + + // icmpv4IdentOffset is the offset of the ident field + // in a ICMPv4EchoRequest/Reply message. + icmpv4IdentOffset = 4 + + // icmpv4SequenceOffset is the offset of the sequence field + // in a ICMPv4EchoRequest/Reply message. + icmpv4SequenceOffset = 6 ) // ICMPv4Type is the ICMP type field described in RFC 792. @@ -72,12 +89,12 @@ func (b ICMPv4) SetCode(c byte) { b[1] = c } // Checksum is the ICMP checksum field. func (b ICMPv4) Checksum() uint16 { - return binary.BigEndian.Uint16(b[2:]) + return binary.BigEndian.Uint16(b[icmpv4ChecksumOffset:]) } // SetChecksum sets the ICMP checksum field. func (b ICMPv4) SetChecksum(checksum uint16) { - binary.BigEndian.PutUint16(b[2:], checksum) + binary.BigEndian.PutUint16(b[icmpv4ChecksumOffset:], checksum) } // SourcePort implements Transport.SourcePort. @@ -102,3 +119,51 @@ func (ICMPv4) SetDestinationPort(uint16) { 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) +} + +// 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, vv buffer.VectorisedView) uint16 { + // Calculate the IPv6 pseudo-header upper-layer checksum. + xsum := uint16(0) + 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 +} diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go index 3cc57e234..1125a7d14 100644 --- a/pkg/tcpip/header/icmpv6.go +++ b/pkg/tcpip/header/icmpv6.go @@ -18,6 +18,7 @@ import ( "encoding/binary" "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/buffer" ) // ICMPv6 represents an ICMPv6 header stored in a byte array. @@ -25,14 +26,18 @@ type ICMPv6 []byte const ( // ICMPv6MinimumSize is the minimum size of a valid ICMP packet. - ICMPv6MinimumSize = 4 + 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 = ICMPv6MinimumSize + 4 + 16 + ICMPv6NeighborSolicitMinimumSize = ICMPv6MinimumSize + 16 // ICMPv6NeighborAdvertSize is size of a neighbor advertisement. ICMPv6NeighborAdvertSize = 32 @@ -42,11 +47,27 @@ const ( // ICMPv6DstUnreachableMinimumSize is the minimum size of a valid ICMP // destination unreachable packet. - ICMPv6DstUnreachableMinimumSize = ICMPv6MinimumSize + 4 + ICMPv6DstUnreachableMinimumSize = ICMPv6MinimumSize // ICMPv6PacketTooBigMinimumSize is the minimum size of a valid ICMP // packet-too-big packet. - ICMPv6PacketTooBigMinimumSize = ICMPv6MinimumSize + 4 + 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 ) // ICMPv6Type is the ICMP type field described in RFC 4443 and friends. @@ -89,12 +110,12 @@ 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[2:]) + return binary.BigEndian.Uint16(b[icmpv6ChecksumOffset:]) } // SetChecksum calculates and sets the ICMP checksum field. func (b ICMPv6) SetChecksum(checksum uint16) { - binary.BigEndian.PutUint16(b[2:], checksum) + binary.BigEndian.PutUint16(b[icmpv6ChecksumOffset:], checksum) } // SourcePort implements Transport.SourcePort. @@ -115,7 +136,60 @@ func (ICMPv6) SetSourcePort(uint16) { 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) +} + // Payload implements Transport.Payload. func (b ICMPv6) Payload() []byte { - return b[ICMPv6MinimumSize:] + 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 } diff --git a/pkg/tcpip/header/ipv4.go b/pkg/tcpip/header/ipv4.go index 17fc9c68e..e5360e7c1 100644 --- a/pkg/tcpip/header/ipv4.go +++ b/pkg/tcpip/header/ipv4.go @@ -21,16 +21,18 @@ import ( ) const ( - versIHL = 0 - tos = 1 - totalLen = 2 - id = 4 - flagsFO = 6 - ttl = 8 - protocol = 9 - checksum = 10 - srcAddr = 12 - dstAddr = 16 + versIHL = 0 + tos = 1 + // IPv4TotalLenOffset is the offset of the total length field in the + // IPv4 header. + IPv4TotalLenOffset = 2 + id = 4 + flagsFO = 6 + ttl = 8 + protocol = 9 + checksum = 10 + srcAddr = 12 + dstAddr = 16 ) // IPv4Fields contains the fields of an IPv4 packet. It is used to describe the @@ -103,6 +105,11 @@ const ( // IPv4Any is the non-routable IPv4 "any" meta address. IPv4Any tcpip.Address = "\x00\x00\x00\x00" + + // IPv4MinimumProcessableDatagramSize is the minimum size of an IP + // packet that every IPv4 capable host must be able to + // process/reassemble. + IPv4MinimumProcessableDatagramSize = 576 ) // Flags that may be set in an IPv4 packet. @@ -163,7 +170,7 @@ func (b IPv4) FragmentOffset() uint16 { // TotalLength returns the "total length" field of the ipv4 header. func (b IPv4) TotalLength() uint16 { - return binary.BigEndian.Uint16(b[totalLen:]) + return binary.BigEndian.Uint16(b[IPv4TotalLenOffset:]) } // Checksum returns the checksum field of the ipv4 header. @@ -209,7 +216,7 @@ func (b IPv4) SetTOS(v uint8, _ uint32) { // SetTotalLength sets the "total length" field of the ipv4 header. func (b IPv4) SetTotalLength(totalLength uint16) { - binary.BigEndian.PutUint16(b[totalLen:], totalLength) + binary.BigEndian.PutUint16(b[IPv4TotalLenOffset:], totalLength) } // SetChecksum sets the checksum field of the ipv4 header. @@ -265,7 +272,7 @@ func (b IPv4) Encode(i *IPv4Fields) { // packets are produced. func (b IPv4) EncodePartial(partialChecksum, totalLength uint16) { b.SetTotalLength(totalLength) - checksum := Checksum(b[totalLen:totalLen+2], partialChecksum) + checksum := Checksum(b[IPv4TotalLenOffset:IPv4TotalLenOffset+2], partialChecksum) b.SetChecksum(^checksum) } @@ -277,7 +284,7 @@ func (b IPv4) IsValid(pktSize int) bool { hlen := int(b.HeaderLength()) tlen := int(b.TotalLength()) - if hlen > tlen || tlen > pktSize { + if hlen < IPv4MinimumSize || hlen > tlen || tlen > pktSize { return false } diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go index 31be42ce0..9d3abc0e4 100644 --- a/pkg/tcpip/header/ipv6.go +++ b/pkg/tcpip/header/ipv6.go @@ -22,12 +22,14 @@ import ( ) const ( - versTCFL = 0 - payloadLen = 4 - nextHdr = 6 - hopLimit = 7 - v6SrcAddr = 8 - v6DstAddr = 24 + versTCFL = 0 + // IPv6PayloadLenOffset is the offset of the PayloadLength field in + // IPv6 header. + IPv6PayloadLenOffset = 4 + nextHdr = 6 + hopLimit = 7 + v6SrcAddr = 8 + v6DstAddr = v6SrcAddr + IPv6AddressSize ) // IPv6Fields contains the fields of an IPv6 packet. It is used to describe the @@ -74,6 +76,13 @@ const ( // IPv6Version is the version of the ipv6 protocol. IPv6Version = 6 + // IPv6AllNodesMulticastAddress is a link-local multicast group that + // all IPv6 nodes MUST join, as per RFC 4291, section 2.8. Packets + // destined to this address will reach all nodes on a link. + // + // The address is ff02::1. + IPv6AllNodesMulticastAddress tcpip.Address = "\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01" + // IPv6MinimumMTU is the minimum MTU required by IPv6, per RFC 2460, // section 5. IPv6MinimumMTU = 1280 @@ -94,7 +103,7 @@ var IPv6EmptySubnet = func() tcpip.Subnet { // PayloadLength returns the value of the "payload length" field of the ipv6 // header. func (b IPv6) PayloadLength() uint16 { - return binary.BigEndian.Uint16(b[payloadLen:]) + return binary.BigEndian.Uint16(b[IPv6PayloadLenOffset:]) } // HopLimit returns the value of the "hop limit" field of the ipv6 header. @@ -119,13 +128,13 @@ func (b IPv6) Payload() []byte { // SourceAddress returns the "source address" field of the ipv6 header. func (b IPv6) SourceAddress() tcpip.Address { - return tcpip.Address(b[v6SrcAddr : v6SrcAddr+IPv6AddressSize]) + return tcpip.Address(b[v6SrcAddr:][:IPv6AddressSize]) } // DestinationAddress returns the "destination address" field of the ipv6 // header. func (b IPv6) DestinationAddress() tcpip.Address { - return tcpip.Address(b[v6DstAddr : v6DstAddr+IPv6AddressSize]) + return tcpip.Address(b[v6DstAddr:][:IPv6AddressSize]) } // Checksum implements Network.Checksum. Given that IPv6 doesn't have a @@ -148,18 +157,18 @@ func (b IPv6) SetTOS(t uint8, l uint32) { // SetPayloadLength sets the "payload length" field of the ipv6 header. func (b IPv6) SetPayloadLength(payloadLength uint16) { - binary.BigEndian.PutUint16(b[payloadLen:], payloadLength) + binary.BigEndian.PutUint16(b[IPv6PayloadLenOffset:], payloadLength) } // SetSourceAddress sets the "source address" field of the ipv6 header. func (b IPv6) SetSourceAddress(addr tcpip.Address) { - copy(b[v6SrcAddr:v6SrcAddr+IPv6AddressSize], addr) + copy(b[v6SrcAddr:][:IPv6AddressSize], addr) } // SetDestinationAddress sets the "destination address" field of the ipv6 // header. func (b IPv6) SetDestinationAddress(addr tcpip.Address) { - copy(b[v6DstAddr:v6DstAddr+IPv6AddressSize], addr) + copy(b[v6DstAddr:][:IPv6AddressSize], addr) } // SetNextHeader sets the value of the "next header" field of the ipv6 header. @@ -178,8 +187,8 @@ func (b IPv6) Encode(i *IPv6Fields) { b.SetPayloadLength(i.PayloadLength) b[nextHdr] = i.NextHeader b[hopLimit] = i.HopLimit - copy(b[v6SrcAddr:v6SrcAddr+IPv6AddressSize], i.SrcAddr) - copy(b[v6DstAddr:v6DstAddr+IPv6AddressSize], i.DstAddr) + b.SetSourceAddress(i.SrcAddr) + b.SetDestinationAddress(i.DstAddr) } // IsValid performs basic validation on the packet. @@ -219,6 +228,24 @@ func IsV6MulticastAddress(addr tcpip.Address) bool { return addr[0] == 0xff } +// IsV6UnicastAddress determines if the provided address is a valid IPv6 +// unicast (and specified) address. That is, IsV6UnicastAddress returns +// true if addr contains IPv6AddressSize bytes, is not the unspecified +// address and is not a multicast address. +func IsV6UnicastAddress(addr tcpip.Address) bool { + if len(addr) != IPv6AddressSize { + return false + } + + // Must not be unspecified + if addr == IPv6Any { + return false + } + + // Return if not a multicast. + return addr[0] != 0xff +} + // SolicitedNodeAddr computes the solicited-node multicast address. This is // used for NDP. Described in RFC 4291. The argument must be a full-length IPv6 // address. diff --git a/pkg/tcpip/header/udp.go b/pkg/tcpip/header/udp.go index c1f454805..74412c894 100644 --- a/pkg/tcpip/header/udp.go +++ b/pkg/tcpip/header/udp.go @@ -27,6 +27,11 @@ const ( udpChecksum = 6 ) +const ( + // UDPMaximumPacketSize is the largest possible UDP packet. + UDPMaximumPacketSize = 0xffff +) + // UDPFields contains the fields of a UDP packet. It is used to describe the // fields of a packet that needs to be encoded. type UDPFields struct { |