waterutil

Documentation

Overview

Package waterutil provides utility functions for interpreting TUN/TAP MAC farme headers and IP packet headers. It defines some constants such as protocol numbers and ethernet frame types. Use waterutil along with package water to work with TUN/TAP interface data.

Frames/packets are interpreted in following format (as in TUN/TAP devices):

TAP - MAC Frame:

 No Tagging
+-----------------------------------------------------------------------------
| Octet |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|...
+-----------------------------------------------------------------------------
| Field | MAC Destination |   MAC  Source   |EType| Payload
+-----------------------------------------------------------------------------

 Single-Tagged -- Octets [12,13] == {0x81, 0x00}
+-----------------------------------------------------------------------------
| Octet |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|...
+-----------------------------------------------------------------------------
| Field | MAC Destination |   MAC  Source   |    Tag    | Payload
+-----------------------------------------------------------------------------

 Double-Tagged -- Octets [12,13] == {0x88, 0xA8}
+-----------------------------------------------------------------------------
| Octet |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|...
+-----------------------------------------------------------------------------
| Field | MAC Destination |   MAC  Source   | Outer Tag | Inner Tag | Payload
+-----------------------------------------------------------------------------

TUN - IPv4 Packet:

+---------------------------------------------------------------------------------------------------------------+
|       | Octet |           0           |           1           |           2           |           3           |
| Octet |  Bit  |00|01|02|03|04|05|06|07|08|09|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|
+---------------------------------------------------------------------------------------------------------------+
|   0   |   0   |  Version  |    IHL    |      DSCP       | ECN |                 Total  Length                 |
+---------------------------------------------------------------------------------------------------------------+
|   4   |  32   |                Identification                 | Flags  |           Fragment Offset            |
+---------------------------------------------------------------------------------------------------------------+
|   8   |  64   |     Time To Live      |       Protocol        |                Header Checksum                |
+---------------------------------------------------------------------------------------------------------------+
|  12   |  96   |                                       Source IP Address                                       |
+---------------------------------------------------------------------------------------------------------------+
|  16   |  128  |                                    Destination IP Address                                     |
+---------------------------------------------------------------------------------------------------------------+
|  20   |  160  |                                     Options (if IHL > 5)                                      |
+---------------------------------------------------------------------------------------------------------------+
|  24   |  192  |                                                                                               |
|  30   |  224  |                                            Payload                                            |
|  ...  |  ...  |                                                                                               |
+---------------------------------------------------------------------------------------------------------------+

Index

• Constants
• Variables
• func IPv4DSCP(packet []byte) byte
• func IPv4Destination(packet []byte) net.IP
• func IPv4DestinationPort(packet []byte) uint16
• func IPv4ECN(packet []byte) byte
• func IPv4Identification(packet []byte) [2]byte
• func IPv4Payload(packet []byte) []byte
• func IPv4Source(packet []byte) net.IP
• func IPv4SourcePort(packet []byte) uint16
• func IPv4TTL(packet []byte) byte
• func IsBroadcast(addr net.HardwareAddr) bool
• func IsIPv4(packet []byte) bool
• func IsIPv4Multicast(addr net.HardwareAddr) bool
• func IsIPv6(packet []byte) bool
• func MACDestination(macFrame []byte) net.HardwareAddr
• func MACPayload(macFrame []byte) []byte
• func MACSource(macFrame []byte) net.HardwareAddr
• func SetIPv4Destination(packet []byte, dest net.IP)
• func SetIPv4DestinationPort(packet []byte, port uint16)
• func SetIPv4Source(packet []byte, source net.IP)
• func SetIPv4SourcePort(packet []byte, port uint16)
• type Ethertype
  • func MACEthertype(macFrame []byte) Ethertype
• type IPProtocol
  • func IPv4Protocol(packet []byte) IPProtocol
• type Tagging
  • func MACTagging(macFrame []byte) Tagging

Constants

const (
	HOPOPT            = 0x00
	ICMP              = 0x01
	IGMP              = 0x02
	GGP               = 0x03
	IPv4Encapsulation = 0x04
	ST                = 0x05
	TCP               = 0x06
	CBT               = 0x07
	EGP               = 0x08
	IGP               = 0x09
	BBN_RCC_MON       = 0x0A
	NVP_II            = 0x0B
	PUP               = 0x0C
	ARGUS             = 0x0D
	EMCON             = 0x0E
	XNET              = 0x0F
	CHAOS             = 0x10
	UDP               = 0x11
	MUX               = 0x12
	DCN_MEAS          = 0x13
	HMP               = 0x14
	PRM               = 0x15
	XNS_IDP           = 0x16
	TRUNK_1           = 0x17
	TRUNK_2           = 0x18
	LEAF_1            = 0x19
	LEAF_2            = 0x1A
	RDP               = 0x1B
	IRTP              = 0x1C
	ISO_TP4           = 0x1D
	NETBLT            = 0x1E
	MFE_NSP           = 0x1F
	MERIT_INP         = 0x20
	DCCP              = 0x21
	ThirdPC           = 0x22
	IDPR              = 0x23
	XTP               = 0x24
	DDP               = 0x25
	IDPR_CMTP         = 0x26
	TPxx              = 0x27
	IL                = 0x28
	IPv6Encapsulation = 0x29
	SDRP              = 0x2A
	IPv6_Route        = 0x2B
	IPv6_Frag         = 0x2C
	IDRP              = 0x2D
	RSVP              = 0x2E
	GRE               = 0x2F
	MHRP              = 0x30
	BNA               = 0x31
	ESP               = 0x32
	AH                = 0x33
	I_NLSP            = 0x34
	SWIPE             = 0x35
	NARP              = 0x36
	MOBILE            = 0x37
	TLSP              = 0x38
	SKIP              = 0x39
	IPv6_ICMP         = 0x3A
	IPv6_NoNxt        = 0x3B
	IPv6_Opts         = 0x3C
	CFTP              = 0x3E
	SAT_EXPAK         = 0x40
	KRYPTOLAN         = 0x41
	RVD               = 0x42
	IPPC              = 0x43
	SAT_MON           = 0x45
	VISA              = 0x46
	IPCV              = 0x47
	CPNX              = 0x48
	CPHB              = 0x49
	WSN               = 0x4A
	PVP               = 0x4B
	BR_SAT_MON        = 0x4C
	SUN_ND            = 0x4D
	WB_MON            = 0x4E
	WB_EXPAK          = 0x4F
	ISO_IP            = 0x50
	VMTP              = 0x51
	SECURE_VMTP       = 0x52
	VINES             = 0x53
	TTP               = 0x54
	IPTM              = 0x54
	NSFNET_IGP        = 0x55
	DGP               = 0x56
	TCF               = 0x57
	EIGRP             = 0x58
	OSPF              = 0x59
	Sprite_RPC        = 0x5A
	LARP              = 0x5B
	MTP               = 0x5C
	AX_25             = 0x5D
	IPIP              = 0x5E
	MICP              = 0x5F
	SCC_SP            = 0x60
	ETHERIP           = 0x61
	ENCAP             = 0x62
	GMTP              = 0x64
	IFMP              = 0x65
	PNNI              = 0x66
	PIM               = 0x67
	ARIS              = 0x68
	SCPS              = 0x69
	QNX               = 0x6A
	A_N               = 0x6B
	IPComp            = 0x6C
	SNP               = 0x6D
	Compaq_Peer       = 0x6E
	IPX_in_IP         = 0x6F
	VRRP              = 0x70
	PGM               = 0x71
	L2TP              = 0x73
	DDX               = 0x74
	IATP              = 0x75
	STP               = 0x76
	SRP               = 0x77
	UTI               = 0x78
	SMP               = 0x79
	SM                = 0x7A
	PTP               = 0x7B
	FIRE              = 0x7D
	CRTP              = 0x7E
	CRUDP             = 0x7F
	SSCOPMCE          = 0x80
	IPLT              = 0x81
	SPS               = 0x82
	PIPE              = 0x83
	SCTP              = 0x84
	FC                = 0x85

	HIP   = 0x8B
	Shim6 = 0x8C
)

IP Protocols. From: http://en.wikipedia.org/wiki/List_of_IP_protocol_numbers

Variables

var (
	IPv4                = Ethertype{0x08, 0x00}
	ARP                 = Ethertype{0x08, 0x06}
	WakeOnLAN           = Ethertype{0x08, 0x42}
	TRILL               = Ethertype{0x22, 0xF3}
	DECnetPhase4        = Ethertype{0x60, 0x03}
	RARP                = Ethertype{0x80, 0x35}
	AppleTalk           = Ethertype{0x80, 0x9B}
	AARP                = Ethertype{0x80, 0xF3}
	IPX1                = Ethertype{0x81, 0x37}
	IPX2                = Ethertype{0x81, 0x38}
	QNXQnet             = Ethertype{0x82, 0x04}
	IPv6                = Ethertype{0x86, 0xDD}
	EthernetFlowControl = Ethertype{0x88, 0x08}
	IEEE802_3           = Ethertype{0x88, 0x09}
	CobraNet            = Ethertype{0x88, 0x19}
	MPLSUnicast         = Ethertype{0x88, 0x47}
	MPLSMulticast       = Ethertype{0x88, 0x48}
	PPPoEDiscovery      = Ethertype{0x88, 0x63}
	PPPoESession        = Ethertype{0x88, 0x64}
	JumboFrames         = Ethertype{0x88, 0x70}
	HomePlug1_0MME      = Ethertype{0x88, 0x7B}
	IEEE802_1X          = Ethertype{0x88, 0x8E}
	PROFINET            = Ethertype{0x88, 0x92}
	HyperSCSI           = Ethertype{0x88, 0x9A}
	AoE                 = Ethertype{0x88, 0xA2}
	EtherCAT            = Ethertype{0x88, 0xA4}
	EthernetPowerlink   = Ethertype{0x88, 0xAB}
	LLDP                = Ethertype{0x88, 0xCC}
	SERCOS3             = Ethertype{0x88, 0xCD}
	HomePlugAVMME       = Ethertype{0x88, 0xE1}
	MRP                 = Ethertype{0x88, 0xE3}
	IEEE802_1AE         = Ethertype{0x88, 0xE5}
	IEEE1588            = Ethertype{0x88, 0xF7}
	IEEE802_1ag         = Ethertype{0x89, 0x02}
	FCoE                = Ethertype{0x89, 0x06}
	FCoEInit            = Ethertype{0x89, 0x14}
	RoCE                = Ethertype{0x89, 0x15}
	CTP                 = Ethertype{0x90, 0x00}
	VeritasLLT          = Ethertype{0xCA, 0xFE}
)

Ethertype values. From: http://en.wikipedia.org/wiki/Ethertype

Functions

func IPv4DSCP

func IPv4DSCP(packet []byte) byte

func IPv4Destination

func IPv4Destination(packet []byte) net.IP

func IPv4DestinationPort

func IPv4DestinationPort(packet []byte) uint16

func IPv4ECN

func IPv4ECN(packet []byte) byte

func IPv4Identification

func IPv4Identification(packet []byte) [2]byte

func IPv4Payload

func IPv4Payload(packet []byte) []byte

func IPv4Source

func IPv4Source(packet []byte) net.IP

func IPv4SourcePort

func IPv4SourcePort(packet []byte) uint16

For TCP/UDP

func IPv4TTL

func IPv4TTL(packet []byte) byte

func IsBroadcast

func IsBroadcast(addr net.HardwareAddr) bool

func IsIPv4

func IsIPv4(packet []byte) bool

func IsIPv4Multicast

func IsIPv4Multicast(addr net.HardwareAddr) bool

func IsIPv6

func IsIPv6(packet []byte) bool

func MACDestination

func MACDestination(macFrame []byte) net.HardwareAddr

func MACPayload

func MACPayload(macFrame []byte) []byte

func MACSource

func MACSource(macFrame []byte) net.HardwareAddr

func SetIPv4Destination

func SetIPv4Destination(packet []byte, dest net.IP)

func SetIPv4DestinationPort

func SetIPv4DestinationPort(packet []byte, port uint16)

func SetIPv4Source

func SetIPv4Source(packet []byte, source net.IP)

func SetIPv4SourcePort

func SetIPv4SourcePort(packet []byte, port uint16)

Types

type Ethertype

type Ethertype [2]byte

func MACEthertype

func MACEthertype(macFrame []byte) Ethertype

type IPProtocol

type IPProtocol byte

func IPv4Protocol

func IPv4Protocol(packet []byte) IPProtocol

type Tagging

type Tagging int

const (
	NotTagged    Tagging = 0
	Tagged       Tagging = 4
	DoubleTagged Tagging = 8
)

Indicating whether/how a MAC frame is tagged. The value is number of bytes taken by tagging.

func MACTagging

func MACTagging(macFrame []byte) Tagging