diff options
| -rw-r--r-- | dhcpv4/dhcpv4.go | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/dhcpv4/dhcpv4.go b/dhcpv4/dhcpv4.go index 0df8cc6..bad2f0c 100644 --- a/dhcpv4/dhcpv4.go +++ b/dhcpv4/dhcpv4.go @@ -46,8 +46,8 @@ func GenerateTransactionID() (*uint32, error) { return &tid, nil } -// Create a new DHCPv4 structure and fill it up with default values. It won't be -// a valid DHCPv4 message so you will need to adjust its fields. +// New creates a new DHCPv4 structure and fill it up with default values. It +// won't be a valid DHCPv4 message so you will need to adjust its fields. // See also NewDiscovery, NewOffer, NewRequest, NewAcknowledge, NewInform and // NewRelease . func New() (*DHCPv4, error) { @@ -79,8 +79,9 @@ func New() (*DHCPv4, error) { return &d, nil } -// Will build a new DHCPv4 Discovery message, with a default Ethernet HW type -// and a null hardware address. The caller needs to fill the remaining fields up +// NewDiscoveryForInterface builds a new DHCPv4 Discovery message, with a default +// Ethernet HW type and the hardware address obtained from the specified +// interface. func NewDiscoveryForInterface(ifname string) (*DHCPv4, error) { d, err := New() if err != nil { @@ -109,7 +110,7 @@ func NewDiscoveryForInterface(ifname string) (*DHCPv4, error) { return d, nil } -// Build a DHCPv4 request from an offer +// RequestFromOffer builds a DHCPv4 request from an offer. func RequestFromOffer(offer DHCPv4) (*DHCPv4, error) { d, err := New() if err != nil { @@ -155,9 +156,11 @@ func RequestFromOffer(offer DHCPv4) (*DHCPv4, error) { return d, nil } +// FromBytes encodes the DHCPv4 packet into a sequence of bytes, and returns an +// error if the packet is not valid. func FromBytes(data []byte) (*DHCPv4, error) { if len(data) < HeaderSize { - return nil, errors.New(fmt.Sprintf("Invalid DHCPv4 header: shorter than %v bytes", HeaderSize)) + return nil, fmt.Errorf("Invalid DHCPv4 header: shorter than %v bytes", HeaderSize) } d := DHCPv4{ opcode: OpcodeType(data[0]), @@ -183,10 +186,12 @@ func FromBytes(data []byte) (*DHCPv4, error) { return &d, nil } +// Opcode returns the OpcodeType for the packet, func (d *DHCPv4) Opcode() OpcodeType { return d.opcode } +// OpcodeToString returns the mnemonic name for the packet's opcode. func (d *DHCPv4) OpcodeToString() string { opcode := OpcodeToString[d.opcode] if opcode == "" { @@ -195,6 +200,8 @@ func (d *DHCPv4) OpcodeToString() string { return opcode } +// SetOpcode sets a new opcode for the packet. It prints a warning if the opcode +// is unknown, but does not generate an error. func (d *DHCPv4) SetOpcode(opcode OpcodeType) { if OpcodeToString[opcode] == "" { log.Printf("Warning: unknown DHCPv4 opcode: %v", opcode) @@ -202,10 +209,13 @@ func (d *DHCPv4) SetOpcode(opcode OpcodeType) { d.opcode = opcode } +// HwType returns the hardware type as defined by IANA. func (d *DHCPv4) HwType() iana.HwTypeType { return d.hwType } +// HwTypeToString returns the mnemonic name for the hardware type, e.g. +// "Ethernet". If the type is unknown, it returns "Unknown". func (d *DHCPv4) HwTypeToString() string { hwtype, ok := iana.HwTypeToString[d.hwType] if !ok { @@ -214,6 +224,7 @@ func (d *DHCPv4) HwTypeToString() string { return hwtype } +// SetHwType returns the hardware type as defined by IANA. func (d *DHCPv4) SetHwType(hwType iana.HwTypeType) { if _, ok := iana.HwTypeToString[hwType]; !ok { log.Printf("Warning: Invalid DHCPv4 hwtype: %v", hwType) @@ -221,10 +232,14 @@ func (d *DHCPv4) SetHwType(hwType iana.HwTypeType) { d.hwType = hwType } +// HwAddrLen returns the hardware address length. E.g. for Ethernet it would +// return 6. func (d *DHCPv4) HwAddrLen() uint8 { return d.hwAddrLen } +// SetHwAddrLen sets the hardware address length, limiting it to the maximum +// size 16 that the standard allows. func (d *DHCPv4) SetHwAddrLen(hwAddrLen uint8) { if hwAddrLen > 16 { log.Printf("Warning: invalid HwAddrLen: %v > 16, using 16 instead", hwAddrLen) @@ -233,18 +248,22 @@ func (d *DHCPv4) SetHwAddrLen(hwAddrLen uint8) { d.hwAddrLen = hwAddrLen } +// HopCount returns the hop count field. func (d *DHCPv4) HopCount() uint8 { return d.hopCount } +// SetHopCount sets the hop count value. func (d *DHCPv4) SetHopCount(hopCount uint8) { d.hopCount = hopCount } +// TransactionID returns the transaction ID as 32 bit unsigned integer. func (d *DHCPv4) TransactionID() uint32 { return d.transactionID } +// SetTransactionID sets the value for the transaction ID. func (d *DHCPv4) SetTransactionID(transactionID uint32) { d.transactionID = transactionID } |