dhcp4

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Published: Jun 24, 2016 License: BSD-3-Clause, Apache-2.0 Imports: 3 Imported by: 0

README

DHCP4 - A DHCP library written in Go.

Warning: This library is still being developed. Function calls will change.

I've removed Server Functionality, for me this project supports the underlying DHCP format not the implementation.

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func IPAdd

func IPAdd(start net.IP, add int) net.IP

IPAdd returns a copy of start + add. IPAdd(net.IP{192,168,1,1},30) returns net.IP{192.168.1.31}

func IPInRange

func IPInRange(start, stop, ip net.IP) bool

IPInRange returns true if ip is between (inclusive) start and stop.

func IPLess

func IPLess(a, b net.IP) bool

IPLess returns where IP a is less than IP b.

func IPRange

func IPRange(start, stop net.IP) int

IPRange returns how many ips in the ip range from start to stop (inclusive)

func JoinIPs

func JoinIPs(ips []net.IP) (b []byte)

JoinIPs returns a byte slice of IP addresses, one immediately after the other This may be useful for creating multiple IP options such as OptionRouter.

func OptionsLeaseTime

func OptionsLeaseTime(d time.Duration) []byte

OptionsLeaseTime - converts a time.Duration to a 4 byte slice, compatible with OptionIPAddressLeaseTime.

Types

type MessageType

type MessageType byte // Option 53
const (
	Discover MessageType = 1 // Broadcast Packet From Client - Can I have an IP?
	Offer    MessageType = 2 // Broadcast From Server - Here's an IP
	Request  MessageType = 3 // Broadcast From Client - I'll take that IP (Also start for renewals)
	Decline  MessageType = 4 // Broadcast From Client - Sorry I can't use that IP
	ACK      MessageType = 5 // From Server, Yes you can have that IP
	NAK      MessageType = 6 // From Server, No you cannot have that IP
	Release  MessageType = 7 // From Client, I don't need that IP anymore
	Inform   MessageType = 8 // From Client, I have this IP and there's nothing you can do about it
)

DHCP Message Type 53

type OpCode

type OpCode byte
const (
	BootRequest OpCode = 1 // From Client
	BootReply   OpCode = 2 // From Server
)

OpCodes

type Option

type Option struct {
	Code  OptionCode
	Value []byte
}

type OptionCode

type OptionCode byte
const (
	End                          OptionCode = 255
	Pad                          OptionCode = 0
	OptionSubnetMask             OptionCode = 1
	OptionTimeOffset             OptionCode = 2
	OptionRouter                 OptionCode = 3
	OptionTimeServer             OptionCode = 4
	OptionNameServer             OptionCode = 5
	OptionDomainNameServer       OptionCode = 6
	OptionLogServer              OptionCode = 7
	OptionCookieServer           OptionCode = 8
	OptionLPRServer              OptionCode = 9
	OptionImpressServer          OptionCode = 10
	OptionResourceLocationServer OptionCode = 11
	OptionHostName               OptionCode = 12
	OptionBootFileSize           OptionCode = 13
	OptionMeritDumpFile          OptionCode = 14
	OptionDomainName             OptionCode = 15
	OptionSwapServer             OptionCode = 16
	OptionRootPath               OptionCode = 17
	OptionExtensionsPath         OptionCode = 18

	// IP Layer Parameters per Host
	OptionIPForwardingEnableDisable          OptionCode = 19
	OptionNonLocalSourceRoutingEnableDisable OptionCode = 20
	OptionPolicyFilter                       OptionCode = 21
	OptionMaximumDatagramReassemblySize      OptionCode = 22
	OptionDefaultIPTimeToLive                OptionCode = 23
	OptionPathMTUAgingTimeout                OptionCode = 24
	OptionPathMTUPlateauTable                OptionCode = 25

	// IP Layer Parameters per Interface
	OptionInterfaceMTU              OptionCode = 26
	OptionAllSubnetsAreLocal        OptionCode = 27
	OptionBroadcastAddress          OptionCode = 28
	OptionPerformMaskDiscovery      OptionCode = 29
	OptionMaskSupplier              OptionCode = 30
	OptionPerformRouterDiscovery    OptionCode = 31
	OptionRouterSolicitationAddress OptionCode = 32
	OptionStaticRoute               OptionCode = 33

	// Link Layer Parameters per Interface
	OptionTrailerEncapsulation  OptionCode = 34
	OptionARPCacheTimeout       OptionCode = 35
	OptionEthernetEncapsulation OptionCode = 36

	// TCP Parameters
	OptionTCPDefaultTTL        OptionCode = 37
	OptionTCPKeepaliveInterval OptionCode = 38
	OptionTCPKeepaliveGarbage  OptionCode = 39

	// Application and Service Parameters
	OptionNetworkInformationServiceDomain            OptionCode = 40
	OptionNetworkInformationServers                  OptionCode = 41
	OptionNetworkTimeProtocolServers                 OptionCode = 42
	OptionVendorSpecificInformation                  OptionCode = 43
	OptionNetBIOSOverTCPIPNameServer                 OptionCode = 44
	OptionNetBIOSOverTCPIPDatagramDistributionServer OptionCode = 45
	OptionNetBIOSOverTCPIPNodeType                   OptionCode = 46
	OptionNetBIOSOverTCPIPScope                      OptionCode = 47
	OptionXWindowSystemFontServer                    OptionCode = 48
	OptionXWindowSystemDisplayManager                OptionCode = 49
	OptionNetworkInformationServicePlusDomain        OptionCode = 64
	OptionNetworkInformationServicePlusServers       OptionCode = 65
	OptionMobileIPHomeAgent                          OptionCode = 68
	OptionSimpleMailTransportProtocol                OptionCode = 69
	OptionPostOfficeProtocolServer                   OptionCode = 70
	OptionNetworkNewsTransportProtocol               OptionCode = 71
	OptionDefaultWorldWideWebServer                  OptionCode = 72
	OptionDefaultFingerServer                        OptionCode = 73
	OptionDefaultInternetRelayChatServer             OptionCode = 74
	OptionStreetTalkServer                           OptionCode = 75
	OptionStreetTalkDirectoryAssistance              OptionCode = 76

	// DHCP Extensions
	OptionRequestedIPAddress     OptionCode = 50
	OptionIPAddressLeaseTime     OptionCode = 51
	OptionOverload               OptionCode = 52
	OptionDHCPMessageType        OptionCode = 53
	OptionServerIdentifier       OptionCode = 54
	OptionParameterRequestList   OptionCode = 55
	OptionMessage                OptionCode = 56
	OptionMaximumDHCPMessageSize OptionCode = 57
	OptionRenewalTimeValue       OptionCode = 58
	OptionRebindingTimeValue     OptionCode = 59
	OptionVendorClassIdentifier  OptionCode = 60
	OptionClientIdentifier       OptionCode = 61

	OptionTFTPServerName OptionCode = 66
	OptionBootFileName   OptionCode = 67

	OptionUserClass OptionCode = 77

	OptionClientArchitecture OptionCode = 93

	OptionTZPOSIXString    OptionCode = 100
	OptionTZDatabaseString OptionCode = 101

	OptionClasslessRouteFormat OptionCode = 121
)

DHCP Options

type Options

type Options map[OptionCode][]byte

Map of DHCP options

func (Options) SelectOrder

func (o Options) SelectOrder(order []byte) []Option

SelectOrder returns a slice of options ordered and selected by a byte array usually defined by OptionParameterRequestList. This result is expected to be used in ReplyPacket()'s []Option parameter.

func (Options) SelectOrderOrAll

func (o Options) SelectOrderOrAll(order []byte) []Option

SelectOrderOrAll has same functionality as SelectOrder, except if the order param is nil, whereby all options are added (in arbitary order).

type Packet

type Packet []byte

A DHCP packet

func NewPacket

func NewPacket(opCode OpCode) Packet

func ReplyPacket

func ReplyPacket(req Packet, mt MessageType, serverId, yIAddr net.IP, leaseDuration time.Duration, options []Option) Packet

ReplyPacket creates a reply packet that a Server would send to a client. It uses the req Packet param to copy across common/necessary fields to associate the reply the request.

func RequestPacket

func RequestPacket(mt MessageType, chAddr net.HardwareAddr, cIAddr net.IP, xId []byte, broadcast bool, options []Option) Packet

Creates a request packet that a Client would send to a server.

func (*Packet) AddOption

func (p *Packet) AddOption(o OptionCode, value []byte)

Appends a DHCP option to the end of a packet

func (Packet) Broadcast

func (p Packet) Broadcast() bool

func (Packet) CHAddr

func (p Packet) CHAddr() net.HardwareAddr

func (Packet) CIAddr

func (p Packet) CIAddr() net.IP

func (Packet) Cookie

func (p Packet) Cookie() []byte

192 bytes of zeros BOOTP legacy

func (Packet) Flags

func (p Packet) Flags() []byte

func (Packet) GIAddr

func (p Packet) GIAddr() net.IP

func (Packet) HLen

func (p Packet) HLen() byte

func (Packet) HType

func (p Packet) HType() byte

func (Packet) Hops

func (p Packet) Hops() byte

func (Packet) OpCode

func (p Packet) OpCode() OpCode

func (Packet) Options

func (p Packet) Options() []byte

func (*Packet) PadToMinSize

func (p *Packet) PadToMinSize()

func (Packet) ParseOptions

func (p Packet) ParseOptions() Options

Parses the packet's options into an Options map

func (Packet) SIAddr

func (p Packet) SIAddr() net.IP

func (Packet) Secs

func (p Packet) Secs() []byte

func (Packet) SetBroadcast

func (p Packet) SetBroadcast(broadcast bool)

func (Packet) SetCHAddr

func (p Packet) SetCHAddr(a net.HardwareAddr)

func (Packet) SetCIAddr

func (p Packet) SetCIAddr(ip net.IP)

func (Packet) SetCookie

func (p Packet) SetCookie(cookie []byte)

func (Packet) SetFlags

func (p Packet) SetFlags(flags []byte)

func (Packet) SetGIAddr

func (p Packet) SetGIAddr(ip net.IP)

func (Packet) SetHType

func (p Packet) SetHType(hType byte)

func (Packet) SetHops

func (p Packet) SetHops(hops byte)

func (Packet) SetOpCode

func (p Packet) SetOpCode(c OpCode)

func (Packet) SetSIAddr

func (p Packet) SetSIAddr(ip net.IP)

func (Packet) SetSecs

func (p Packet) SetSecs(secs []byte)

func (Packet) SetXId

func (p Packet) SetXId(xId []byte)

func (Packet) SetYIAddr

func (p Packet) SetYIAddr(ip net.IP)

func (*Packet) StripOptions

func (p *Packet) StripOptions()

Removes all options from packet.

func (Packet) XId

func (p Packet) XId() []byte

func (Packet) YIAddr

func (p Packet) YIAddr() net.IP

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