97 lines
3.0 KiB
Go
97 lines
3.0 KiB
Go
// Package ipamutils provides utility functions for ipam management
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package ipamutils
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import (
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"fmt"
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"net"
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"sync"
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"github.com/sirupsen/logrus"
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)
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var (
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// PredefinedBroadNetworks contains a list of 31 IPv4 private networks with host size 16 and 12
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// (172.17-31.x.x/16, 192.168.x.x/20) which do not overlap with the networks in `PredefinedGranularNetworks`
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PredefinedBroadNetworks []*net.IPNet
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// PredefinedGranularNetworks contains a list of 64K IPv4 private networks with host size 8
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// (10.x.x.x/24) which do not overlap with the networks in `PredefinedBroadNetworks`
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PredefinedGranularNetworks []*net.IPNet
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initNetworksOnce sync.Once
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defaultBroadNetwork = []*NetworkToSplit{{"172.17.0.0/16", 16}, {"172.18.0.0/16", 16}, {"172.19.0.0/16", 16},
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{"172.20.0.0/14", 16}, {"172.24.0.0/14", 16}, {"172.28.0.0/14", 16},
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{"192.168.0.0/16", 20}}
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defaultGranularNetwork = []*NetworkToSplit{{"10.0.0.0/8", 24}}
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)
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// NetworkToSplit represent a network that has to be split in chunks with mask length Size.
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// Each subnet in the set is derived from the Base pool. Base is to be passed
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// in CIDR format.
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// Example: a Base "10.10.0.0/16 with Size 24 will define the set of 256
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// 10.10.[0-255].0/24 address pools
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type NetworkToSplit struct {
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Base string `json:"base"`
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Size int `json:"size"`
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}
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// InitNetworks initializes the broad network pool and the granular network pool
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func InitNetworks(defaultAddressPool []*NetworkToSplit) {
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initNetworksOnce.Do(func() {
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// error ingnored should never fail
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PredefinedGranularNetworks, _ = splitNetworks(defaultGranularNetwork)
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if defaultAddressPool == nil {
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defaultAddressPool = defaultBroadNetwork
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}
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var err error
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if PredefinedBroadNetworks, err = splitNetworks(defaultAddressPool); err != nil {
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logrus.WithError(err).Error("InitAddressPools failed to initialize the default address pool")
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}
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})
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}
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// splitNetworks takes a slice of networks, split them accordingly and returns them
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func splitNetworks(list []*NetworkToSplit) ([]*net.IPNet, error) {
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localPools := make([]*net.IPNet, 0, len(list))
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for _, p := range list {
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_, b, err := net.ParseCIDR(p.Base)
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if err != nil {
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return nil, fmt.Errorf("invalid base pool %q: %v", p.Base, err)
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}
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ones, _ := b.Mask.Size()
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if p.Size <= 0 || p.Size < ones {
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return nil, fmt.Errorf("invalid pools size: %d", p.Size)
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}
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localPools = append(localPools, splitNetwork(p.Size, b)...)
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}
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return localPools, nil
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}
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func splitNetwork(size int, base *net.IPNet) []*net.IPNet {
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one, bits := base.Mask.Size()
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mask := net.CIDRMask(size, bits)
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n := 1 << uint(size-one)
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s := uint(bits - size)
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list := make([]*net.IPNet, 0, n)
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for i := 0; i < n; i++ {
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ip := copyIP(base.IP)
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addIntToIP(ip, uint(i<<s))
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list = append(list, &net.IPNet{IP: ip, Mask: mask})
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}
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return list
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}
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func copyIP(from net.IP) net.IP {
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ip := make([]byte, len(from))
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copy(ip, from)
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return ip
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}
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func addIntToIP(array net.IP, ordinal uint) {
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for i := len(array) - 1; i >= 0; i-- {
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array[i] |= (byte)(ordinal & 0xff)
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ordinal >>= 8
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}
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}
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