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utils.go
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utils.go
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// Package ipamutils provides utility functions for ipam management
package ipamutils
import (
"fmt"
"net"
"sync"
)
var (
// predefinedLocalScopeDefaultNetworks contains a list of 31 IPv4 private networks with host size 16 and 12
// (172.17-31.x.x/16, 192.168.x.x/20) which do not overlap with the networks in `PredefinedGlobalScopeDefaultNetworks`
predefinedLocalScopeDefaultNetworks []*net.IPNet
// predefinedGlobalScopeDefaultNetworks contains a list of 64K IPv4 private networks with host size 8
// (10.x.x.x/24) which do not overlap with the networks in `PredefinedLocalScopeDefaultNetworks`
predefinedGlobalScopeDefaultNetworks []*net.IPNet
mutex sync.Mutex
localScopeDefaultNetworks = []*NetworkToSplit{
{"172.17.0.0/16", 16},
{"172.18.0.0/16", 16},
{"172.19.0.0/16", 16},
{"172.20.0.0/14", 16},
{"172.24.0.0/14", 16},
{"172.28.0.0/14", 16},
{"192.168.0.0/16", 20},
}
globalScopeDefaultNetworks = []*NetworkToSplit{{"10.0.0.0/8", 24}}
)
// NetworkToSplit represent a network that has to be split in chunks with mask length Size.
// Each subnet in the set is derived from the Base pool. Base is to be passed
// in CIDR format.
// Example: a Base "10.10.0.0/16 with Size 24 will define the set of 256
// 10.10.[0-255].0/24 address pools
type NetworkToSplit struct {
Base string `json:"base"`
Size int `json:"size"`
}
func init() {
var err error
if predefinedGlobalScopeDefaultNetworks, err = SplitNetworks(globalScopeDefaultNetworks); err != nil {
panic("failed to initialize the global scope default address pool: " + err.Error())
}
if predefinedLocalScopeDefaultNetworks, err = SplitNetworks(localScopeDefaultNetworks); err != nil {
panic("failed to initialize the local scope default address pool: " + err.Error())
}
}
// ConfigGlobalScopeDefaultNetworks configures global default pool.
// Ideally this will be called from SwarmKit as part of swarm init
func ConfigGlobalScopeDefaultNetworks(defaultAddressPool []*NetworkToSplit) error {
if defaultAddressPool == nil {
return nil
}
mutex.Lock()
defer mutex.Unlock()
defaultNetworks, err := SplitNetworks(defaultAddressPool)
if err != nil {
return err
}
predefinedGlobalScopeDefaultNetworks = defaultNetworks
return nil
}
// GetGlobalScopeDefaultNetworks returns a copy of the global-sopce network list.
func GetGlobalScopeDefaultNetworks() []*net.IPNet {
mutex.Lock()
defer mutex.Unlock()
return append([]*net.IPNet(nil), predefinedGlobalScopeDefaultNetworks...)
}
// GetLocalScopeDefaultNetworks returns a copy of the default local-scope network list.
func GetLocalScopeDefaultNetworks() []*net.IPNet {
return append([]*net.IPNet(nil), predefinedLocalScopeDefaultNetworks...)
}
// SplitNetworks takes a slice of networks, split them accordingly and returns them
func SplitNetworks(list []*NetworkToSplit) ([]*net.IPNet, error) {
localPools := make([]*net.IPNet, 0, len(list))
for _, p := range list {
_, b, err := net.ParseCIDR(p.Base)
if err != nil {
return nil, fmt.Errorf("invalid base pool %q: %v", p.Base, err)
}
ones, _ := b.Mask.Size()
if p.Size <= 0 || p.Size < ones {
return nil, fmt.Errorf("invalid pools size: %d", p.Size)
}
localPools = append(localPools, splitNetwork(p.Size, b)...)
}
return localPools, nil
}
func splitNetwork(size int, base *net.IPNet) []*net.IPNet {
one, bits := base.Mask.Size()
mask := net.CIDRMask(size, bits)
n := 1 << uint(size-one)
s := uint(bits - size)
list := make([]*net.IPNet, 0, n)
for i := 0; i < n; i++ {
ip := copyIP(base.IP)
addIntToIP(ip, uint(i<<s))
list = append(list, &net.IPNet{IP: ip, Mask: mask})
}
return list
}
func copyIP(from net.IP) net.IP {
ip := make([]byte, len(from))
copy(ip, from)
return ip
}
func addIntToIP(array net.IP, ordinal uint) {
for i := len(array) - 1; i >= 0; i-- {
array[i] |= (byte)(ordinal & 0xff)
ordinal >>= 8
}
}