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package bsdp
import (
"encoding/binary"
"fmt"
"github.com/insomniacslk/dhcp/dhcpv4"
)
// Implements the BSDP option reply port. This is used when BSDP responses
// should be sent to a reply port other than the DHCP default. The macOS GUI
// "Startup Disk Select" sends this option since it's operating in an
// unprivileged context.
// OptReplyPort represents a BSDP protocol version.
type OptReplyPort struct {
Port uint16
}
// ParseOptReplyPort constructs an OptReplyPort struct from a sequence of
// bytes and returns it, or an error.
func ParseOptReplyPort(data []byte) (*OptReplyPort, error) {
if len(data) < 4 {
return nil, dhcpv4.ErrShortByteStream
}
code := dhcpv4.OptionCode(data[0])
if code != OptionReplyPort {
return nil, fmt.Errorf("expected option %v, got %v instead", OptionReplyPort, code)
}
length := int(data[1])
if length != 2 {
return nil, fmt.Errorf("expected length 2, got %d instead", length)
}
port := binary.BigEndian.Uint16(data[2:4])
return &OptReplyPort{port}, nil
}
// Code returns the option code.
func (o *OptReplyPort) Code() dhcpv4.OptionCode {
return OptionReplyPort
}
// ToBytes returns a serialized stream of bytes for this option.
func (o *OptReplyPort) ToBytes() []byte {
serialized := make([]byte, 2)
binary.BigEndian.PutUint16(serialized, o.Port)
return append([]byte{byte(o.Code()), 2}, serialized...)
}
// String returns a human-readable string for this option.
func (o *OptReplyPort) String() string {
return fmt.Sprintf("BSDP Reply Port -> %v", o.Port)
}
// Length returns the length of the data portion of this option.
func (o *OptReplyPort) Length() int {
return 2
}
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