mirror of
https://github.com/crazy-max/diun.git
synced 2024-12-22 19:38:28 +00:00
92 lines
2.8 KiB
Go
92 lines
2.8 KiB
Go
/*
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Copyright 2018 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package net
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import (
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"errors"
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"fmt"
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"math"
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"math/big"
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"net"
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"strconv"
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)
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// ParseCIDRs parses a list of cidrs and return error if any is invalid.
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// order is maintained
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func ParseCIDRs(cidrsString []string) ([]*net.IPNet, error) {
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cidrs := make([]*net.IPNet, 0, len(cidrsString))
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for i, cidrString := range cidrsString {
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_, cidr, err := ParseCIDRSloppy(cidrString)
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if err != nil {
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return nil, fmt.Errorf("invalid CIDR[%d]: %v (%v)", i, cidr, err)
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}
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cidrs = append(cidrs, cidr)
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}
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return cidrs, nil
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}
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// ParsePort parses a string representing an IP port. If the string is not a
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// valid port number, this returns an error.
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func ParsePort(port string, allowZero bool) (int, error) {
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portInt, err := strconv.ParseUint(port, 10, 16)
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if err != nil {
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return 0, err
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}
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if portInt == 0 && !allowZero {
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return 0, errors.New("0 is not a valid port number")
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}
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return int(portInt), nil
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}
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// BigForIP creates a big.Int based on the provided net.IP
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func BigForIP(ip net.IP) *big.Int {
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// NOTE: Convert to 16-byte representation so we can
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// handle v4 and v6 values the same way.
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return big.NewInt(0).SetBytes(ip.To16())
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}
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// AddIPOffset adds the provided integer offset to a base big.Int representing a net.IP
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// NOTE: If you started with a v4 address and overflow it, you get a v6 result.
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func AddIPOffset(base *big.Int, offset int) net.IP {
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r := big.NewInt(0).Add(base, big.NewInt(int64(offset))).Bytes()
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r = append(make([]byte, 16), r...)
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return net.IP(r[len(r)-16:])
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}
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// RangeSize returns the size of a range in valid addresses.
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// returns the size of the subnet (or math.MaxInt64 if the range size would overflow int64)
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func RangeSize(subnet *net.IPNet) int64 {
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ones, bits := subnet.Mask.Size()
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if bits == 32 && (bits-ones) >= 31 || bits == 128 && (bits-ones) >= 127 {
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return 0
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}
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// this checks that we are not overflowing an int64
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if bits-ones >= 63 {
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return math.MaxInt64
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}
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return int64(1) << uint(bits-ones)
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}
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// GetIndexedIP returns a net.IP that is subnet.IP + index in the contiguous IP space.
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func GetIndexedIP(subnet *net.IPNet, index int) (net.IP, error) {
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ip := AddIPOffset(BigForIP(subnet.IP), index)
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if !subnet.Contains(ip) {
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return nil, fmt.Errorf("can't generate IP with index %d from subnet. subnet too small. subnet: %q", index, subnet)
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}
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return ip, nil
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}
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