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package dhcpv6
/*
This module defines the OptVendorOpts structure.
https://tools.ietf.org/html/rfc3315#section-22.17
Option 17
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_VENDOR_OPTS | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| enterprise-number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. option-data (sub-options) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Sub-Option
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| opt-code | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. option-data .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
import (
"encoding/binary"
"errors"
"fmt"
)
// OptVendorOpts represents a DHCPv6 Status Code option
type OptVendorOpts struct {
EnterpriseNumber uint32
VendorOpts Options
}
// Code returns the option code
func (op *OptVendorOpts) Code() OptionCode {
return OptionVendorOpts
}
// ToBytes serializes the option and returns it as a sequence of bytes
func (op *OptVendorOpts) ToBytes() []byte {
buf := make([]byte, 8)
binary.BigEndian.PutUint16(buf[0:2], uint16(OptionVendorOpts))
binary.BigEndian.PutUint16(buf[2:4], uint16(op.Length()))
binary.BigEndian.PutUint32(buf[4:8], uint32(op.EnterpriseNumber))
for _, opt := range op.VendorOpts {
buf = append(buf, opt.ToBytes()...)
}
return buf
}
// Length returns the option length
func (op *OptVendorOpts) Length() int {
l := 4 // 4 bytes for Enterprise Number
for _, opt := range op.VendorOpts {
l += 4 + opt.Length() // 4 bytes for Code and Length from Vendor
}
return l
}
// String returns a string representation of the VendorOpts data
func (op *OptVendorOpts) String() string {
return fmt.Sprintf("OptVendorOpts{enterprisenum=%v, vendorOpts=%v}",
op.EnterpriseNumber, op.VendorOpts,
)
}
// ParseOptVendorOpts builds an OptVendorOpts structure from a sequence of bytes.
// The input data does not include option code and length bytes.
func ParseOptVendorOpts(data []byte) (*OptVendorOpts, error) {
opt := OptVendorOpts{}
if len(data) < 4 {
return nil, fmt.Errorf("Invalid vendor opts data length. Expected at least 4 bytes, got %v", len(data))
}
opt.EnterpriseNumber = binary.BigEndian.Uint32(data[:4])
if err := opt.VendorOpts.FromBytesWithParser(data[4:], vendParseOption); err != nil {
return nil, err
}
return &opt, nil
}
// vendParseOption builds a GenericOption from a slice of bytes
// We cannot use the existing ParseOption function in options.go because the
// sub-options include codes specific to each vendor. There are overlaps in these
// codes with RFC standard codes.
func vendParseOption(dataStart []byte) (Option, error) {
// Parse a sequence of bytes as a single DHCPv6 option.
// Returns the option structure, or an error if any.
if len(dataStart) < 4 {
return nil, fmt.Errorf("Invalid DHCPv6 vendor option: less than 4 bytes")
}
code := OptionCode(binary.BigEndian.Uint16(dataStart[:2]))
length := int(binary.BigEndian.Uint16(dataStart[2:4]))
if len(dataStart) < length+4 {
return nil, fmt.Errorf("Invalid option length for vendor option %v. Declared %v, actual %v",
code, length, len(dataStart)-4,
)
}
optData := dataStart[4 : 4+length]
if len(optData) < 1 {
return nil, errors.New("vendParseOption: at least one vendor options data is required")
}
return &OptionGeneric{OptionCode: code, OptionData: optData}, nil
}
|
