dhcp

Documentation

Index

• Variables
• func Arch(d *dhcpv4.DHCPv4) iana.Arch
• func IsNetbootClient(pkt *dhcpv4.DHCPv4) error
• type ClientType
  • func (c ClientType) String() string
• type Info
  • func NewInfo(pkt *dhcpv4.DHCPv4) Info
  • func (i Info) AddRPIOpt43(opts dhcpv4.Options) []byte
  • func (i Info) Bootfile(customUC UserClass, ipxeScript, ipxeHTTPBinServer *url.URL, ...) string
  • func (i Info) ClientTypeFrom() ClientType
  • func (i Info) IPXEBinaryFrom() string
  • func (i Info) NextServer(ipxeHTTPBinServer *url.URL, ipxeTFTPBinServer netip.AddrPort) net.IP
  • func (i Info) UserClassFrom() UserClass
• type UserClass
  • func (u UserClass) String() string

Variables

var ArchToBootFile = map[iana.Arch]string{
	iana.INTEL_X86PC:       "undionly.kpxe",
	iana.NEC_PC98:          "undionly.kpxe",
	iana.EFI_ITANIUM:       "undionly.kpxe",
	iana.DEC_ALPHA:         "undionly.kpxe",
	iana.ARC_X86:           "undionly.kpxe",
	iana.INTEL_LEAN_CLIENT: "undionly.kpxe",
	iana.EFI_IA32:          "ipxe.efi",
	iana.EFI_X86_64:        "ipxe.efi",
	iana.EFI_XSCALE:        "ipxe.efi",
	iana.EFI_BC:            "ipxe.efi",
	iana.EFI_ARM32:         "snp.efi",
	iana.EFI_ARM64:         "snp.efi",
	iana.EFI_X86_HTTP:      "ipxe.efi",
	iana.EFI_X86_64_HTTP:   "ipxe.efi",
	iana.EFI_ARM32_HTTP:    "snp.efi",
	iana.EFI_ARM64_HTTP:    "snp.efi",
	iana.Arch(41):          "snp.efi",
}

ArchToBootFile maps supported hardware PXE architectures types to iPXE binary files.

var ErrUnknownArch = fmt.Errorf("could not determine client architecture from option 93")

ErrUnknownArch is used when the PXE client request is from an unknown architecture.

Functions

func Arch

func Arch(d *dhcpv4.DHCPv4) iana.Arch

Arch returns the Arch of the client pulled from DHCP option 93.

func IsNetbootClient

func IsNetbootClient(pkt *dhcpv4.DHCPv4) error

IsNetbootClient returns nil if the client is a valid netboot client. Otherwise it returns an error.

A valid netboot client will have the following in its DHCP request: 1. is a DHCP discovery/request message type. 2. option 93 is set. 3. option 94 is set. 4. option 97 is correct length. 5. option 60 is set with this format: "PXEClient:Arch:xxxxx:UNDI:yyyzzz" or "HTTPClient:Arch:xxxxx:UNDI:yyyzzz".

See: http://www.pix.net/software/pxeboot/archive/pxespec.pdf

See: https://www.rfc-editor.org/rfc/rfc4578.html

Types

type ClientType

type ClientType string

ClientType is from DHCP option 60. Normally only PXEClient or HTTPClient.

const (
	PXEClient  ClientType = "PXEClient"
	HTTPClient ClientType = "HTTPClient"
)

func (ClientType) String

func (c ClientType) String() string

String function for clientType.

type Info

type Info struct {
	// Pkt is the dhcp packet that was received from the client.
	Pkt *dhcpv4.DHCPv4
	// Arch is the architecture of the client. Use NewInfo to automatically populate this field.
	Arch iana.Arch
	// Mac is the mac address of the client. Use NewInfo to automatically populate this field.
	Mac net.HardwareAddr
	// UserClass is the user class of the client. Use NewInfo to automatically populate this field.
	UserClass UserClass
	// ClientType is the client type of the client. Use NewInfo to automatically populate this field.
	ClientType ClientType
	// IsNetbootClient returns nil if the client is a valid netboot client.	Otherwise it returns an error.
	// Use NewInfo to automatically populate this field.
	IsNetbootClient error
	// IPXEBinary is the iPXE binary file to boot. Use NewInfo to automatically populate this field.
	IPXEBinary string
}

Info holds details about the dhcp request. Use NewInfo to populate the struct fields from a dhcp packet.

func NewInfo

func NewInfo(pkt *dhcpv4.DHCPv4) Info

func (Info) AddRPIOpt43

func (i Info) AddRPIOpt43(opts dhcpv4.Options) []byte

AddRPIOpt43 adds the Raspberry PI required option43 sub options to an existing opt 43.

func (Info) Bootfile

func (i Info) Bootfile(customUC UserClass, ipxeScript, ipxeHTTPBinServer *url.URL, ipxeTFTPBinServer netip.AddrPort) string

Bootfile returns the calculated dhcp header: "file" value. see https://datatracker.ietf.org/doc/html/rfc2131#section-2 .

func (Info) ClientTypeFrom

func (i Info) ClientTypeFrom() ClientType

func (Info) IPXEBinaryFrom

func (i Info) IPXEBinaryFrom() string

func (Info) NextServer

func (i Info) NextServer(ipxeHTTPBinServer *url.URL, ipxeTFTPBinServer netip.AddrPort) net.IP

NextServer returns the calculated dhcp header (ServerIPAddr): "siaddr" value. see https://datatracker.ietf.org/doc/html/rfc2131#section-2 .

func (Info) UserClassFrom

func (i Info) UserClassFrom() UserClass

type UserClass

type UserClass string

UserClass is DHCP option 77 (https://www.rfc-editor.org/rfc/rfc3004.html).

const (
	// If the client has had iPXE burned into its ROM (or is a VM
	// that uses iPXE as the PXE "ROM"), special handling is
	// needed because in this mode the client is using iPXE native
	// drivers and chainloading to a UNDI stack won't work.
	IPXE UserClass = "iPXE"
	// If the client identifies as "Tinkerbell", we've already
	// chainloaded this client to the full-featured copy of iPXE
	// we supply. We have to distinguish this case so we don't
	// loop on the chainload step.
	Tinkerbell UserClass = "Tinkerbell"
)

known user-class types. must correspond to DHCP option 77 - User-Class https://www.rfc-editor.org/rfc/rfc3004.html

func (UserClass) String

func (u UserClass) String() string

String function for UserClass.