IPAllocator: Ensure the allocated IPs are within network range.

Since it is possible to request a specific IP, IPAllocator has to verify
that the request is within boundaries.

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

daemon/networkdriver/ipallocator/allocator.go

@@ -34,8 +34,9 @@ type networkSet map[string]*allocatedMap
 var (
 	ErrNoAvailableIPs           = errors.New("no available ip addresses on network")
 	ErrIPAlreadyAllocated       = errors.New("ip already allocated")
+	ErrIPOutOfRange             = errors.New("requested ip is out of range")
 	ErrNetworkAlreadyRegistered = errors.New("network already registered")
-	ErrBadSubnet                = errors.New("network not contains specified subnet")
+	ErrBadSubnet                = errors.New("network does not contain specified subnet")
 )
 
 var (
@@ -100,11 +101,21 @@ func ReleaseIP(network *net.IPNet, ip net.IP) error {
 
 func (allocated *allocatedMap) checkIP(ip net.IP) (net.IP, error) {
 	pos := ipToInt(ip)
+
+	// Verify that the IP address has not been already allocated.
 	if _, ok := allocated.p[pos]; ok {
 		return nil, ErrIPAlreadyAllocated
 	}
+
+	// Verify that the IP address is within our network range.
+	if pos < allocated.begin || pos > allocated.end {
+		return nil, ErrIPOutOfRange
+	}
+
+	// Register the IP.
 	allocated.p[pos] = struct{}{}
 	allocated.last = pos
+
 	return ip, nil
 }
 

daemon/networkdriver/ipallocator/allocator_test.go

@@ -97,18 +97,29 @@ func TestGetReleasedIp(t *testing.T) {
 	}
 }
 
-func TestRequesetSpecificIp(t *testing.T) {
+func TestRequestSpecificIp(t *testing.T) {
 	defer reset()
 	network := &net.IPNet{
 		IP:   []byte{192, 168, 0, 1},
-		Mask: []byte{255, 255, 255, 0},
+		Mask: []byte{255, 255, 255, 224},
 	}
 
-	ip := net.ParseIP("192.168.1.5")
+	ip := net.ParseIP("192.168.0.5")
 
+	// Request a "good" IP.
 	if _, err := RequestIP(network, ip); err != nil {
 		t.Fatal(err)
 	}
+
+	// Request the same IP again.
+	if _, err := RequestIP(network, ip); err != ErrIPAlreadyAllocated {
+		t.Fatalf("Got the same IP twice: %#v", err)
+	}
+
+	// Request an out of range IP.
+	if _, err := RequestIP(network, net.ParseIP("192.168.0.42")); err != ErrIPOutOfRange {
+		t.Fatalf("Got an out of range IP: %#v", err)
+	}
 }
 
 func TestConversion(t *testing.T) {