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package bsdp
import (
"fmt"
"github.com/insomniacslk/dhcp/dhcpv4"
)
// Implements the BSDP option listing the boot images.
// OptBootImageList contains the list of boot images presented by a netboot
// server.
type OptBootImageList struct {
Images []BootImage
}
// ParseOptBootImageList constructs an OptBootImageList struct from a sequence
// of bytes and returns it, or an error.
func ParseOptBootImageList(data []byte) (*OptBootImageList, error) {
// Should have at least code + length
if len(data) < 2 {
return nil, dhcpv4.ErrShortByteStream
}
code := dhcpv4.OptionCode(data[0])
if code != OptionBootImageList {
return nil, fmt.Errorf("expected option %v, got %v instead", OptionBootImageList, code)
}
length := int(data[1])
if len(data) < length+2 {
return nil, fmt.Errorf("expected length %d, got %d instead", length, len(data))
}
// Offset from code + length byte
var bootImages []BootImage
idx := 2
for {
if idx >= length+2 {
break
}
image, err := BootImageFromBytes(data[idx:])
if err != nil {
return nil, fmt.Errorf("parsing bytes stream: %v", err)
}
bootImages = append(bootImages, *image)
// 4 bytes of BootImageID, 1 byte of name length, name
idx += 4 + 1 + len(image.Name)
}
return &OptBootImageList{bootImages}, nil
}
// Code returns the option code.
func (o *OptBootImageList) Code() dhcpv4.OptionCode {
return OptionBootImageList
}
// ToBytes returns a serialized stream of bytes for this option.
func (o *OptBootImageList) ToBytes() []byte {
bs := make([]byte, 0, 2+o.Length())
bs = append(bs, []byte{byte(o.Code()), byte(o.Length())}...)
for _, image := range o.Images {
bs = append(bs, image.ToBytes()...)
}
return bs
}
// String returns a human-readable string for this option.
func (o *OptBootImageList) String() string {
s := "BSDP Boot Image List ->"
for _, image := range o.Images {
s += "\n " + image.String()
}
return s
}
// Length returns the length of the data portion of this option.
func (o *OptBootImageList) Length() int {
length := 0
for _, image := range o.Images {
length += 4 + 1 + len(image.Name)
}
return length
}
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