dhcp4

package module
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 Go to latest Published: Sep 4, 2017 License: BSD-3-Clause Imports: 3 Imported by: 121

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 arbitrary 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

Source Files

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