netlink: Fix RTM_SETLINK padding at the end of the message

While the kernel seems to have accepted the message to set linkmode and
operstate without the final attribute getting padded to 32-bit length,
it is better to get this cleaned up to match expected format. The double
NLMSG_ALIGN() followed by RTA_LENGTH() did not make much sense here.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/drivers/netlink.c

@@ -199,8 +199,7 @@ int netlink_send_oper_ifla(struct netlink_data *netlink, int ifindex,
 		rta->rta_type = IFLA_LINKMODE;
 		rta->rta_len = RTA_LENGTH(sizeof(char));
 		*((char *) RTA_DATA(rta)) = linkmode;
-		req.hdr.nlmsg_len = NLMSG_ALIGN(req.hdr.nlmsg_len) +
-			RTA_LENGTH(sizeof(char));
+		req.hdr.nlmsg_len += RTA_SPACE(sizeof(char));
 	}
 	if (operstate != -1) {
 		rta = aliasing_hide_typecast(
@@ -209,8 +208,7 @@ int netlink_send_oper_ifla(struct netlink_data *netlink, int ifindex,
 		rta->rta_type = IFLA_OPERSTATE;
 		rta->rta_len = RTA_LENGTH(sizeof(char));
 		*((char *) RTA_DATA(rta)) = operstate;
-		req.hdr.nlmsg_len = NLMSG_ALIGN(req.hdr.nlmsg_len) +
-			RTA_LENGTH(sizeof(char));
+		req.hdr.nlmsg_len += RTA_SPACE(sizeof(char));
 	}
 
 	wpa_printf(MSG_DEBUG, "netlink: Operstate: ifindex=%d linkmode=%d (%s), operstate=%d (%s)",

src/drivers/priv_netlink.h

@@ -68,6 +68,7 @@
 ((attrlen) -= RTA_ALIGN((rta)->rta_len), \
 (struct rtattr *) (((char *)(rta)) + RTA_ALIGN((rta)->rta_len)))
 #define RTA_LENGTH(len) (RTA_ALIGN(sizeof(struct rtattr)) + (len))
+#define RTA_SPACE(len) RTA_ALIGN(RTA_LENGTH(len))
 #define RTA_DATA(rta) ((void *) (((char *) (rta)) + RTA_LENGTH(0)))
 #define RTA_PAYLOAD(rta) ((int) ((rta)->rta_len) - RTA_LENGTH(0))