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