shared: improve NM_ETHER_ADDR_INIT() helper macro

The macro should require exactly 6 parameters (for the 6 bytes
of the address). On the other hand, we also should be able to
use a macro like

  NM_ETHER_ADDR_INIT(NM_BRIDGE_GROUP_ADDRESS_DEF_BIN)

To get that work properly, we need to expand the variadic macro
once.

Also, cast the result to the struct type. With this, it can
not only be used for initialization, but also for assignment
and temporary variables.

2 files changed, 13 insertions, 4 deletions

diff --git a/shared/nm-glib-aux/nm-shared-utils.h b/shared/nm-glib-aux/nm-shared-utils.h
index 2848ce860a..dd094a2cbd 100644
--- a/shared/nm-glib-aux/nm-shared-utils.h
+++ b/shared/nm-glib-aux/nm-shared-utils.h
@@ -93,11 +93,20 @@ typedef struct {
     (x)->ether_addr_octet[0], (x)->ether_addr_octet[1], (x)->ether_addr_octet[2], \
         (x)->ether_addr_octet[3], (x)->ether_addr_octet[4], (x)->ether_addr_octet[5]
 
-#define NM_ETHER_ADDR_INIT(...)            \
-    {                                      \
-        .ether_addr_octet = {__VA_ARGS__}, \
+#define _NM_ETHER_ADDR_INIT(a0, a1, a2, a3, a4, a5) \
+    {                                               \
+        .ether_addr_octet = {                       \
+            (a0),                                   \
+            (a1),                                   \
+            (a2),                                   \
+            (a3),                                   \
+            (a4),                                   \
+            (a5),                                   \
+        },                                          \
     }
 
+#define NM_ETHER_ADDR_INIT(...) ((NMEtherAddr) _NM_ETHER_ADDR_INIT(__VA_ARGS__))
+
 static inline int
 nm_ether_addr_cmp(const NMEtherAddr *a, const NMEtherAddr *b)
 {
diff --git a/src/devices/nm-device-bridge.c b/src/devices/nm-device-bridge.c
index 4f2d3f30e0..64a530a26b 100644
--- a/src/devices/nm-device-bridge.c
+++ b/src/devices/nm-device-bridge.c
@@ -169,7 +169,7 @@ static void
 to_sysfs_group_address_sys(const char *group_address, NMEtherAddr *out_addr)
 {
     if (group_address == NULL) {
-        *out_addr = (NMEtherAddr) NM_ETHER_ADDR_INIT(NM_BRIDGE_GROUP_ADDRESS_DEF_BIN);
+        *out_addr = NM_ETHER_ADDR_INIT(NM_BRIDGE_GROUP_ADDRESS_DEF_BIN);
         return;
     }
     if (!nm_utils_hwaddr_aton(group_address, out_addr, ETH_ALEN))