diff --git a/Network/Socket/Posix/CmsgHdr.hsc b/Network/Socket/Posix/CmsgHdr.hsc
index f122ea3b..fe827bf3 100644
--- a/Network/Socket/Posix/CmsgHdr.hsc
+++ b/Network/Socket/Posix/CmsgHdr.hsc
@@ -22,7 +22,11 @@ import Network.Socket.Posix.MsgHdr
 import Network.Socket.Types
 
 data CmsgHdr = CmsgHdr {
-    cmsgHdrLen   :: !CInt
+#ifdef __linux__
+    cmsgHdrLen   :: !CSize
+#else
+    cmsgHdrLen   :: !(#type socklen_t)
+#endif
   , cmsgHdrLevel :: !CInt
   , cmsgHdrType  :: !CInt
   } deriving (Eq, Show)
@@ -61,7 +65,7 @@ withCmsgs cmsgs0 action
 
 toCmsgHdr :: Cmsg -> Ptr CmsgHdr -> IO ()
 toCmsgHdr (Cmsg (CmsgId lvl typ) (PS fptr off len)) ctrlPtr = do
-    poke ctrlPtr $ CmsgHdr (c_cmsg_len (fromIntegral len)) lvl typ
+    poke ctrlPtr $ CmsgHdr (fromIntegral $ c_cmsg_len (fromIntegral len)) lvl typ
     withForeignPtr fptr $ \src0 -> do
         let src = src0 `plusPtr` off
         dst <- c_cmsg_data ctrlPtr
@@ -96,7 +100,7 @@ foreign import ccall unsafe "cmsg_data"
   c_cmsg_data :: Ptr CmsgHdr -> IO (Ptr Word8)
 
 foreign import ccall unsafe "cmsg_space"
-  c_cmsg_space :: CInt -> CInt
+  c_cmsg_space :: CSize -> CSize
 
 foreign import ccall unsafe "cmsg_len"
-  c_cmsg_len :: CInt -> CInt
+  c_cmsg_len :: CSize -> CSize
diff --git a/Network/Socket/Posix/MsgHdr.hsc b/Network/Socket/Posix/MsgHdr.hsc
index 40b1c7a5..9d072be2 100644
--- a/Network/Socket/Posix/MsgHdr.hsc
+++ b/Network/Socket/Posix/MsgHdr.hsc
@@ -15,11 +15,19 @@ import Network.Socket.Posix.IOVec (IOVec)
 
 data MsgHdr sa = MsgHdr
     { msgName    :: !(Ptr sa)
-    , msgNameLen :: !CUInt
+    , msgNameLen :: !(#type socklen_t)
     , msgIov     :: !(Ptr IOVec)
+#ifdef __linux__
     , msgIovLen  :: !CSize
+#else
+    , msgIovLen  :: !CInt
+#endif
     , msgCtrl    :: !(Ptr Word8)
-    , msgCtrlLen :: !CInt
+#ifdef __linux__
+    , msgCtrlLen :: !CSize
+#else
+    , msgCtrlLen :: !(#type socklen_t)
+#endif
     , msgFlags   :: !CInt
     }
 
diff --git a/cbits/cmsg.c b/cbits/cmsg.c
index c532f5ad..105dd197 100644
--- a/cbits/cmsg.c
+++ b/cbits/cmsg.c
@@ -87,11 +87,11 @@ unsigned char *cmsg_data(struct cmsghdr *cmsg) {
   return (CMSG_DATA(cmsg));
 }
 
-int cmsg_space(int l) {
+size_t cmsg_space(size_t l) {
   return (CMSG_SPACE(l));
 }
 
-int cmsg_len(int l) {
+size_t cmsg_len(size_t l) {
   return (CMSG_LEN(l));
 }
 #endif /* _WIN32 */
diff --git a/include/HsNet.h b/include/HsNet.h
index ba016148..b623a97e 100644
--- a/include/HsNet.h
+++ b/include/HsNet.h
@@ -126,11 +126,11 @@ cmsg_nxthdr(struct msghdr *mhdr, struct cmsghdr *cmsg);
 extern unsigned char *
 cmsg_data(struct cmsghdr *cmsg);
 
-extern int
-cmsg_space(int l);
+extern size_t
+cmsg_space(size_t l);
 
-extern int
-cmsg_len(int l);
+extern size_t
+cmsg_len(size_t l);
 #endif /* _WIN32 */
 
 INLINE int