diff options
Diffstat (limited to 'dhcpv4/dhcpv4.go')
| -rw-r--r-- | dhcpv4/dhcpv4.go | 37 |
1 files changed, 30 insertions, 7 deletions
diff --git a/dhcpv4/dhcpv4.go b/dhcpv4/dhcpv4.go index a88be19..2d73003 100644 --- a/dhcpv4/dhcpv4.go +++ b/dhcpv4/dhcpv4.go @@ -112,6 +112,8 @@ func New() (*DHCPv4, error) { return nil, err } d.options = options + // the End option has to be added explicitly + d.AddOption(&OptionGeneric{OptionCode: OptionEnd}) return &d, nil } @@ -142,14 +144,12 @@ func NewDiscoveryForInterface(ifname string) (*DHCPv4, error) { OptionDomainNameServer, }, }) - // the End option has to be added explicitly - d.AddOption(&OptionGeneric{OptionCode: OptionEnd}) return d, nil } // NewInformForInterface builds a new DHCPv4 Informational message with default // Ethernet HW type and the hardware address obtained from the specified -// interface. It does NOT put a DHCP End option at the end. +// interface. func NewInformForInterface(ifname string, needsBroadcast bool) (*DHCPv4, error) { d, err := New() if err != nil { @@ -214,11 +214,26 @@ func RequestFromOffer(offer DHCPv4) (*DHCPv4, error) { d.AddOption(&OptMessageType{MessageType: MessageTypeRequest}) d.AddOption(&OptRequestedIPAddress{RequestedAddr: offer.YourIPAddr()}) d.AddOption(&OptServerIdentifier{ServerID: serverIP}) - // the End option has to be added explicitly - d.AddOption(&OptionGeneric{OptionCode: OptionEnd}) return d, nil } +// NewReplyFromRequest builds a DHCPv4 reply from a request. +func NewReplyFromRequest(request *DHCPv4) (*DHCPv4, error) { + reply, err := New() + if err != nil { + return nil, err + } + reply.SetOpcode(OpcodeBootReply) + reply.SetHwType(request.HwType()) + reply.SetHwAddrLen(request.HwAddrLen()) + hwaddr := request.ClientHwAddr() + reply.SetClientHwAddr(hwaddr[:]) + reply.SetTransactionID(request.TransactionID()) + reply.SetFlags(request.Flags()) + reply.SetGatewayIPAddr(request.GatewayIPAddr()) + return reply, 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) { @@ -556,9 +571,17 @@ func (d *DHCPv4) SetOptions(options []Option) { d.options = options } -// AddOption appends an option to the existing ones. +// AddOption appends an option to the existing ones. If the last option is an +// OptionEnd, it will be inserted before that. It does not deal with End +// options that appead before the end, like in malformed packets. func (d *DHCPv4) AddOption(option Option) { - d.options = append(d.options, option) + if len(d.options) == 0 || d.options[len(d.options)-1].Code() != OptionEnd { + d.options = append(d.options, option) + } else { + end := d.options[len(d.options)-1] + d.options[len(d.options)-1] = option + d.options = append(d.options, end) + } } // MessageType returns the message type, trying to extract it from the |