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
View File

@ -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
}

34
plugins/ipam/host-local/allocator_test.go
View File

@ -77,26 +77,26 @@ var _ = Describe("host-local ip allocator", func() {
{
subnet: "10.0.0.0/29",
ipmap: map[string]string{},
expectResult: "10.0.0.7",
lastIP: "10.0.0.6",
expectResult: "10.0.0.6",
lastIP: "10.0.0.5",
},
{
subnet: "10.0.0.0/29",
ipmap: map[string]string{
"10.0.0.4": "id",
"10.0.0.5": "id",
"10.0.0.6": "id",
},
expectResult: "10.0.0.7",
lastIP: "10.0.0.4",
expectResult: "10.0.0.6",
lastIP: "10.0.0.3",
},
// round robin to the beginning
{
subnet: "10.0.0.0/29",
ipmap: map[string]string{
"10.0.0.7": "id",
"10.0.0.6": "id",
},
expectResult: "10.0.0.2",
lastIP: "10.0.0.6",
lastIP: "10.0.0.5",
},
// lastIP is out of range
{
@ -116,7 +116,7 @@ var _ = Describe("host-local ip allocator", func() {
}
})
It("should allocate the last address if RangeEnd not given", func() {
It("should not allocate the broadcast address", func() {
subnet, err := types.ParseCIDR("192.168.1.0/24")
Expect(err).ToNot(HaveOccurred())
@ -129,7 +129,7 @@ var _ = Describe("host-local ip allocator", func() {
alloc, err := NewIPAllocator(&conf, store)
Expect(err).ToNot(HaveOccurred())
for i := 1; i < 255; i++ {
for i := 1; i < 254; i++ {
res, err := alloc.Get("ID")
Expect(err).ToNot(HaveOccurred())
// i+1 because the gateway address is skipped
@ -318,4 +318,20 @@ var _ = Describe("host-local ip allocator", func() {
}
})
})
Context("when given an invalid subnet", func() {
It("returns a meaningful error", func() {
subnet, err := types.ParseCIDR("192.168.1.0/31")
Expect(err).ToNot(HaveOccurred())
conf := IPAMConfig{
Name: "test",
Type: "host-local",
Subnet: types.IPNet{IP: subnet.IP, Mask: subnet.Mask},
}
store := fakestore.NewFakeStore(map[string]string{}, net.ParseIP(""))
_, err = NewIPAllocator(&conf, store)
Expect(err).To(HaveOccurred())
})
})
})