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package dhcpv6
// This module defines the OptDNSRecursiveNameServer structure.
// https://www.ietf.org/rfc/rfc3646.txt
import (
"encoding/binary"
"fmt"
"net"
)
// OptDNSRecursiveNameServer represents a DNS_RECURSIVE_NAME_SERVER option
type OptDNSRecursiveNameServer struct {
NameServers []net.IP
}
// Code returns the option code
func (op *OptDNSRecursiveNameServer) Code() OptionCode {
return DNS_RECURSIVE_NAME_SERVER
}
// ToBytes returns the option serialized to bytes, including option code and
// length
func (op *OptDNSRecursiveNameServer) ToBytes() []byte {
buf := make([]byte, 4)
binary.BigEndian.PutUint16(buf[0:2], uint16(DNS_RECURSIVE_NAME_SERVER))
binary.BigEndian.PutUint16(buf[2:4], uint16(op.Length()))
for _, ns := range op.NameServers {
buf = append(buf, ns...)
}
return buf
}
// Length returns the option length
func (op *OptDNSRecursiveNameServer) Length() int {
return len(op.NameServers) * net.IPv6len
}
func (op *OptDNSRecursiveNameServer) String() string {
return fmt.Sprintf("OptDNSRecursiveNameServer{nameservers=%v}", op.NameServers)
}
// ParseOptDNSRecursiveNameServer builds an OptDNSRecursiveNameServer structure
// from a sequence of bytes. The input data does not include option code and length
// bytes.
func ParseOptDNSRecursiveNameServer(data []byte) (*OptDNSRecursiveNameServer, error) {
if len(data)%net.IPv6len != 0 {
return nil, fmt.Errorf("Invalid OptDNSRecursiveNameServer data: length is not a multiple of %d", net.IPv6len)
}
opt := OptDNSRecursiveNameServer{}
var nameServers []net.IP
for i := 0; i < len(data); i += net.IPv6len {
nameServers = append(nameServers, data[i:i+net.IPv6len])
}
opt.NameServers = nameServers
return &opt, nil
}
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