diff options
Diffstat (limited to 'pkg/tcpip/header')
| -rw-r--r-- | pkg/tcpip/header/icmpv4.go | 50 | ||||
| -rw-r--r-- | pkg/tcpip/header/icmpv6.go | 35 | ||||
| -rw-r--r-- | pkg/tcpip/header/ipv4.go | 5 |
3 files changed, 81 insertions, 9 deletions
diff --git a/pkg/tcpip/header/icmpv4.go b/pkg/tcpip/header/icmpv4.go index be03fb086..c00bcadfb 100644 --- a/pkg/tcpip/header/icmpv4.go +++ b/pkg/tcpip/header/icmpv4.go @@ -31,6 +31,27 @@ const ( // 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 @@ -39,15 +60,19 @@ const ( icmpv4ChecksumOffset = 2 // icmpv4MTUOffset is the offset of the MTU field - // in a ICMPv4FragmentationNeeded message. + // in an ICMPv4FragmentationNeeded message. icmpv4MTUOffset = 6 // icmpv4IdentOffset is the offset of the ident field - // in a ICMPv4EchoRequest/Reply message. + // 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 a ICMPv4EchoRequest/Reply message. + // in an ICMPv4EchoRequest/Reply message. icmpv4SequenceOffset = 6 ) @@ -72,15 +97,23 @@ const ( ICMPv4InfoReply ICMPv4Type = 16 ) +// ICMP codes for ICMPv4 Time Exceeded messages as defined in RFC 792. +const ( + ICMPv4TTLExceeded ICMPv4Code = 0 +) + // ICMP codes for ICMPv4 Destination Unreachable messages as defined in RFC 792. const ( - ICMPv4TTLExceeded ICMPv4Code = 0 + ICMPv4NetUnreachable ICMPv4Code = 0 ICMPv4HostUnreachable ICMPv4Code = 1 ICMPv4ProtoUnreachable ICMPv4Code = 2 ICMPv4PortUnreachable ICMPv4Code = 3 ICMPv4FragmentationNeeded ICMPv4Code = 4 ) +// 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]) } @@ -93,6 +126,15 @@ 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) } +// SetPointer sets the pointer field in a Parameter error packet. +// This is the first byte of the type specific data field. +func (b ICMPv4) SetPointer(c byte) { b[icmpv4PointerOffset] = c } + +// SetTypeSpecific sets the full 32 bit type specific data field. +func (b ICMPv4) SetTypeSpecific(val uint32) { + binary.BigEndian.PutUint32(b[icmpv4PointerOffset:], val) +} + // Checksum is the ICMP checksum field. func (b ICMPv4) Checksum() uint16 { return binary.BigEndian.Uint16(b[icmpv4ChecksumOffset:]) diff --git a/pkg/tcpip/header/icmpv6.go b/pkg/tcpip/header/icmpv6.go index 20b01d8f4..4eb5abd79 100644 --- a/pkg/tcpip/header/icmpv6.go +++ b/pkg/tcpip/header/icmpv6.go @@ -54,9 +54,17 @@ const ( // address. ICMPv6NeighborAdvertSize = ICMPv6HeaderSize + NDPNAMinimumSize + NDPLinkLayerAddressSize - // ICMPv6EchoMinimumSize is the minimum size of a valid ICMP echo packet. + // ICMPv6EchoMinimumSize is the minimum size of a valid echo packet. ICMPv6EchoMinimumSize = 8 + // ICMPv6ErrorHeaderSize is the size of an ICMP error packet header, + // as per RFC 4443, Apendix A, item 4 and the errata. + // ... all ICMP error messages shall have exactly + // 32 bits of type-specific data, so that receivers can reliably find + // the embedded invoking packet even when they don't recognize the + // ICMP message Type. + ICMPv6ErrorHeaderSize = 8 + // ICMPv6DstUnreachableMinimumSize is the minimum size of a valid ICMP // destination unreachable packet. ICMPv6DstUnreachableMinimumSize = ICMPv6MinimumSize @@ -69,6 +77,10 @@ const ( // in an ICMPv6 message. icmpv6ChecksumOffset = 2 + // icmpv6PointerOffset is the offset of the pointer + // in an ICMPv6 Parameter problem message. + icmpv6PointerOffset = 4 + // icmpv6MTUOffset is the offset of the MTU field in an ICMPv6 // PacketTooBig message. icmpv6MTUOffset = 4 @@ -89,9 +101,10 @@ const ( NDPHopLimit = 255 ) -// ICMPv6Type is the ICMP type field described in RFC 4443 and friends. +// ICMPv6Type is the ICMP type field described in RFC 4443. type ICMPv6Type byte +// Values for use in the Type field of ICMPv6 packet from RFC 4433. const ( ICMPv6DstUnreachable ICMPv6Type = 1 ICMPv6PacketTooBig ICMPv6Type = 2 @@ -109,7 +122,18 @@ const ( ICMPv6RedirectMsg ICMPv6Type = 137 ) -// ICMPv6Code is the ICMP code field described in RFC 4443. +// IsErrorType returns true if the receiver is an ICMP error type. +func (typ ICMPv6Type) IsErrorType() bool { + // Per RFC 4443 section 2.1: + // ICMPv6 messages are grouped into two classes: error messages and + // informational messages. Error messages are identified as such by a + // zero in the high-order bit of their message Type field values. Thus, + // error messages have message types from 0 to 127; informational + // messages have message types from 128 to 255. + return typ&0x80 == 0 +} + +// ICMPv6Code is the ICMP Code field described in RFC 4443. type ICMPv6Code byte // ICMP codes used with Destination Unreachable (Type 1). As per RFC 4443 @@ -153,6 +177,11 @@ func (b ICMPv6) Code() ICMPv6Code { return ICMPv6Code(b[1]) } // SetCode sets the ICMP code field. func (b ICMPv6) SetCode(c ICMPv6Code) { b[1] = byte(c) } +// SetTypeSpecific sets the full 32 bit type specific data field. +func (b ICMPv6) SetTypeSpecific(val uint32) { + binary.BigEndian.PutUint32(b[icmpv6PointerOffset:], val) +} + // Checksum is the ICMP checksum field. func (b ICMPv6) Checksum() uint16 { return binary.BigEndian.Uint16(b[icmpv6ChecksumOffset:]) diff --git a/pkg/tcpip/header/ipv4.go b/pkg/tcpip/header/ipv4.go index e8816c3f4..b07d9991d 100644 --- a/pkg/tcpip/header/ipv4.go +++ b/pkg/tcpip/header/ipv4.go @@ -80,7 +80,8 @@ type IPv4Fields struct { type IPv4 []byte const ( - // IPv4MinimumSize is the minimum size of a valid IPv4 packet. + // IPv4MinimumSize is the minimum size of a valid IPv4 packet; + // i.e. a packet header with no options. IPv4MinimumSize = 20 // IPv4MaximumHeaderSize is the maximum size of an IPv4 header. Given @@ -327,7 +328,7 @@ func IsV4MulticastAddress(addr tcpip.Address) bool { } // IsV4LoopbackAddress determines if the provided address is an IPv4 loopback -// address (belongs to 127.0.0.1/8 subnet). +// address (belongs to 127.0.0.0/8 subnet). See RFC 1122 section 3.2.1.3. func IsV4LoopbackAddress(addr tcpip.Address) bool { if len(addr) != IPv4AddressSize { return false |