ITQC/containernetworking-plugins
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host-local: don't allocate the broadcast address or allow invalid networks

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There aren't any IPs to allocate in /32 or /31 networks, so don't allow them.
This commit is contained in:
Dan Williams
2016-09-02 17:20:09 -05:00
parent 959af1e6ab
commit 95a9ea0bd2
2 changed files with 40 additions and 9 deletions
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15
plugins/ipam/host-local/allocator.go
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@ -34,6 +34,13 @@ type IPAllocator struct {
}
func NewIPAllocator(conf *IPAMConfig, store backend.Store) (*IPAllocator, error) {
// Can't create an allocator for a network with no addresses, eg
// a /32 or /31
ones, masklen := conf.Subnet.Mask.Size()
if ones > masklen-2 {
return nil, fmt.Errorf("Network %v too small to allocate from", conf.Subnet)
}
var (
start net.IP
end net.IP
@ -195,6 +202,8 @@ func (a *IPAllocator) Release(id string) error {
return a.store.ReleaseByID(id)
}
// Return the start and end IP addresses of a given subnet, excluding
// the broadcast address (eg, 192.168.1.255)
func networkRange(ipnet *net.IPNet) (net.IP, net.IP, error) {
if ipnet.IP == nil {
return nil, nil, fmt.Errorf("missing field %q in IPAM configuration", "subnet")
@ -212,6 +221,12 @@ func networkRange(ipnet *net.IPNet) (net.IP, net.IP, error) {
for i := 0; i < len(ip); i++ {
end = append(end, ip[i]|^ipnet.Mask[i])
}
// Exclude the broadcast address for IPv4
if ip.To4() != nil {
end[3]--
}
return ipnet.IP, end, nil
}