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|
package bsdp
import (
"errors"
"fmt"
"strings"
"github.com/insomniacslk/dhcp/dhcpv4"
)
// OptVendorSpecificInformation encapsulates the BSDP-specific options used for
// the protocol.
type OptVendorSpecificInformation struct {
Options []dhcpv4.Option
}
// parseOption is similar to dhcpv4.ParseOption, except that it switches based
// on the BSDP specific options.
func parseOption(data []byte) (dhcpv4.Option, error) {
if len(data) == 0 {
return nil, dhcpv4.ErrZeroLengthByteStream
}
var (
opt dhcpv4.Option
err error
)
switch dhcpv4.OptionCode(data[0]) {
case OptionBootImageList:
opt, err = ParseOptBootImageList(data)
case OptionDefaultBootImageID:
opt, err = ParseOptDefaultBootImageID(data)
case OptionMachineName:
opt, err = ParseOptMachineName(data)
case OptionMessageType:
opt, err = ParseOptMessageType(data)
case OptionReplyPort:
opt, err = ParseOptReplyPort(data)
case OptionSelectedBootImageID:
opt, err = ParseOptSelectedBootImageID(data)
case OptionServerIdentifier:
opt, err = ParseOptServerIdentifier(data)
case OptionServerPriority:
opt, err = ParseOptServerPriority(data)
case OptionVersion:
opt, err = ParseOptVersion(data)
default:
opt, err = ParseOptGeneric(data)
}
if err != nil {
return nil, err
}
return opt, nil
}
// ParseOptVendorSpecificInformation constructs an OptVendorSpecificInformation struct from a sequence of
// bytes and returns it, or an error.
func ParseOptVendorSpecificInformation(data []byte) (*OptVendorSpecificInformation, error) {
// Should at least have code + length
if len(data) < 2 {
return nil, dhcpv4.ErrShortByteStream
}
code := dhcpv4.OptionCode(data[0])
if code != dhcpv4.OptionVendorSpecificInformation {
return nil, fmt.Errorf("expected option %v, got %v instead", dhcpv4.OptionVendorSpecificInformation, code)
}
length := int(data[1])
if len(data) < length+2 {
return nil, fmt.Errorf("expected length 2, got %d instead", length)
}
options := make([]dhcpv4.Option, 0, 10)
idx := 2
for {
if idx == len(data) {
break
}
// This should never happen.
if idx > len(data) {
return nil, errors.New("read past the end of options")
}
opt, err := parseOption(data[idx:])
if err != nil {
return nil, err
}
options = append(options, opt)
// Account for code + length bytes
idx += 2 + opt.Length()
}
return &OptVendorSpecificInformation{options}, nil
}
// Code returns the option code.
func (o *OptVendorSpecificInformation) Code() dhcpv4.OptionCode {
return dhcpv4.OptionVendorSpecificInformation
}
// ToBytes returns a serialized stream of bytes for this option.
func (o *OptVendorSpecificInformation) ToBytes() []byte {
bs := []byte{byte(o.Code()), byte(o.Length())}
// Append data section
for _, opt := range o.Options {
bs = append(bs, opt.ToBytes()...)
}
return bs
}
// String returns a human-readable string for this option.
func (o *OptVendorSpecificInformation) String() string {
s := "Vendor Specific Information ->"
for _, opt := range o.Options {
optString := opt.String()
// If this option has sub-structures, offset them accordingly.
if strings.Contains(optString, "\n") {
optString = strings.Replace(optString, "\n ", "\n ", -1)
}
s += "\n " + optString
}
return s
}
// Length returns the length of the data portion of this option. Take into
// account code + data length bytes for each sub option.
func (o *OptVendorSpecificInformation) Length() int {
var length int
for _, opt := range o.Options {
length += 2 + opt.Length()
}
return length
}
// GetOptions returns all suboptions that match the given OptionCode code.
func (o *OptVendorSpecificInformation) GetOptions(code dhcpv4.OptionCode) []dhcpv4.Option {
var opts []dhcpv4.Option
for _, opt := range o.Options {
if opt.Code() == code {
opts = append(opts, opt)
}
}
return opts
}
// GetOption returns the first suboption that matches the OptionCode code.
func (o *OptVendorSpecificInformation) GetOption(code dhcpv4.OptionCode) dhcpv4.Option {
opts := o.GetOptions(code)
if len(opts) == 0 {
return nil
}
return opts[0]
}
|
