81 lines
1.8 KiB
Go
81 lines
1.8 KiB
Go
package networkdriver
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import (
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"encoding/binary"
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"errors"
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"github.com/dotcloud/docker/pkg/netlink"
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"net"
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)
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var (
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ErrNetworkOverlapsWithNameservers = errors.New("requested network overlaps with nameserver")
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ErrNetworkOverlaps = errors.New("requested network overlaps with existing network")
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)
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var (
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networkGetRoutesFct = netlink.NetworkGetRoutes
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)
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func CheckNameserverOverlaps(nameservers []string, toCheck *net.IPNet) error {
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if len(nameservers) > 0 {
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for _, ns := range nameservers {
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_, nsNetwork, err := net.ParseCIDR(ns)
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if err != nil {
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return err
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}
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if NetworkOverlaps(toCheck, nsNetwork) {
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return ErrNetworkOverlapsWithNameservers
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}
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}
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}
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return nil
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}
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func CheckRouteOverlaps(toCheck *net.IPNet) error {
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networks, err := networkGetRoutesFct()
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if err != nil {
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return err
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}
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for _, network := range networks {
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if network.IPNet != nil && NetworkOverlaps(toCheck, network.IPNet) {
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return ErrNetworkOverlaps
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}
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}
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return nil
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}
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// Detects overlap between one IPNet and another
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func NetworkOverlaps(netX *net.IPNet, netY *net.IPNet) bool {
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if firstIP, _ := NetworkRange(netX); netY.Contains(firstIP) {
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return true
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}
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if firstIP, _ := NetworkRange(netY); netX.Contains(firstIP) {
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return true
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}
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return false
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}
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// Calculates the first and last IP addresses in an IPNet
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func NetworkRange(network *net.IPNet) (net.IP, net.IP) {
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var (
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netIP = network.IP.To4()
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firstIP = netIP.Mask(network.Mask)
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lastIP = net.IPv4(0, 0, 0, 0).To4()
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)
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for i := 0; i < len(lastIP); i++ {
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lastIP[i] = netIP[i] | ^network.Mask[i]
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}
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return firstIP, lastIP
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}
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// Given a netmask, calculates the number of available hosts
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func NetworkSize(mask net.IPMask) int32 {
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m := net.IPv4Mask(0, 0, 0, 0)
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for i := 0; i < net.IPv4len; i++ {
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m[i] = ^mask[i]
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}
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return int32(binary.BigEndian.Uint32(m)) + 1
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}
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