[PATCH stable-2.12] Fix the computation of the list of reserved IP addresses

['Petr Pudlak' via ganeti-devel]

After refactoring the code for network addresses to Haskell, a
regression appeared that added 30 to all IP addresses in the generated
list. Since the code for generating the list used just 'show' and look
for 0s and 1s in the string (and treating anything else as 0), it turned
  out that after adding a separate type for address pools, the strings
  become

    "AddressPool {apReservations = ...}"

and the initial part of the string was exactly the mysterious 30
characters.

This fix replaces this by switching to correct types and iterating over
the bits in BitArray.

Fixes #1068.

Signed-off-by: Petr Pudlak <pud...@google.com>
---
 src/Ganeti/Query/Network.hs | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/src/Ganeti/Query/Network.hs b/src/Ganeti/Query/Network.hs
index 7963ec3..68dc925 100644
--- a/src/Ganeti/Query/Network.hs
+++ b/src/Ganeti/Query/Network.hs
@@ -44,11 +44,12 @@ module Ganeti.Query.Network
 
 import qualified Data.Map as Map
 import Data.Maybe (fromMaybe, mapMaybe)
-import Data.List (find, foldl', intercalate)
+import Data.List (find, intercalate)
 
 import Ganeti.JSON
 import Ganeti.Network
 import Ganeti.Objects
+import qualified Ganeti.Objects.BitArray as BA
 import Ganeti.Query.Language
 import Ganeti.Query.Common
 import Ganeti.Query.Types
@@ -165,24 +166,17 @@ getNetworkUuid cfg name =
 -- | Computes the reservations list for a network.
 --
 -- This doesn't use the netmask for validation of the length, instead
--- simply iterating over the reservations string.
-getReservations :: Ip4Network -> String -> [Ip4Address]
-getReservations net =
-  reverse .
-  fst .
-  foldl' (\(accu, addr) c ->
-            let addr' = nextIp4Address addr
-                accu' = case c of
-                          '1' -> addr:accu
-                          '0' -> accu
-                          _ -> -- FIXME: the reservations string
-                               -- should be a proper type
-                               accu
-            in (accu', addr')) ([], ip4netAddr net)
+-- simply iterating over the reservations.
+getReservations :: Ip4Network -> Maybe AddressPool -> [Ip4Address]
+getReservations _ Nothing = []
+getReservations net (Just pool) =
+  map snd . filter fst
+  $ zip (BA.toList . apReservations $ pool)
+        (iterate nextIp4Address $ ip4netAddr net)
 
 -- | Computes the external reservations as string for a network.
 getExtReservationsString :: Network -> ResultEntry
 getExtReservationsString net =
   let addrs = getReservations (networkNetwork net)
-              (maybe "" show $ networkExtReservations net)
+                              (networkExtReservations net)
   in rsNormal . intercalate ", " $ map show addrs
-- 
2.2.0.rc0.207.ga3a616c