// Copyright 2016 CNI authors // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package hwaddr import ( "fmt" "net" ) const ( ipRelevantByteLen = 4 PrivateMACPrefixString = "0a:58" ) var ( // private mac prefix safe to use PrivateMACPrefix = []byte{0x0a, 0x58} ) type SupportIp4OnlyErr struct{ msg string } func (e SupportIp4OnlyErr) Error() string { return e.msg } type MacParseErr struct{ msg string } func (e MacParseErr) Error() string { return e.msg } type InvalidPrefixLengthErr struct{ msg string } func (e InvalidPrefixLengthErr) Error() string { return e.msg } // GenerateHardwareAddr4 generates 48 bit virtual mac addresses based on the IP4 input. func GenerateHardwareAddr4(ip net.IP, prefix []byte) (net.HardwareAddr, error) { switch { case ip.To4() == nil: return nil, SupportIp4OnlyErr{msg: "GenerateHardwareAddr4 only supports valid IPv4 address as input"} case len(prefix) != len(PrivateMACPrefix): return nil, InvalidPrefixLengthErr{msg: fmt.Sprintf( "Prefix has length %d instead of %d", len(prefix), len(PrivateMACPrefix)), } } ipByteLen := len(ip) return (net.HardwareAddr)( append( prefix, ip[ipByteLen-ipRelevantByteLen:ipByteLen]...), ), nil }