net/netdev: Check quota when registering lower-half devices

Some drivers may set too big quota by accident and consume all of our
buffers, so we add a check when registering devices.

Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>

drivers/net/netdev_upperhalf.c

@@ -115,6 +115,40 @@ static int quota_fetch_dec(FAR struct netdev_lowerhalf_s *lower,
 #endif
 }
 
+/****************************************************************************
+ * Name: quota_is_valid
+ *
+ * Description:
+ *   Check if the quota of the lower half is not too big.
+ *
+ ****************************************************************************/
+
+static bool quota_is_valid(FAR struct netdev_lowerhalf_s *lower)
+{
+  int total = 0;
+  int type;
+
+  for (type = 0; type < NETPKT_TYPENUM; type++)
+    {
+      total += netdev_lower_quota_load(lower, type);
+    }
+
+  if (total > NETPKT_BUFNUM)
+    {
+      nerr("ERROR: Too big quota when registering device: %d\n", total);
+      return false;
+    }
+
+  if (total > NETPKT_BUFNUM / 2)
+    {
+      nwarn("WARNING: The quota of the registering device may consume more "
+            "than half of the network buffers, which may hurt performance. "
+            "Please consider decreasing driver quota or increasing nIOB.\n");
+    }
+
+  return true;
+}
+
 /****************************************************************************
  * Name: netpkt_get
  *
@@ -1029,7 +1063,7 @@ int netdev_lower_register(FAR struct netdev_lowerhalf_s *dev,
   FAR struct netdev_upperhalf_s *upper;
   int ret;
 
-  if (dev == NULL || dev->ops == NULL ||
+  if (dev == NULL || quota_is_valid(dev) == false || dev->ops == NULL ||
       dev->ops->transmit == NULL || dev->ops->receive == NULL)
     {
       return -EINVAL;

include/nuttx/net/netdev_lowerhalf.h

@@ -69,6 +69,7 @@
  */
 
 #define NETPKT_BUFLEN   CONFIG_IOB_BUFSIZE
+#define NETPKT_BUFNUM   CONFIG_IOB_NBUFFERS
 
 /****************************************************************************
  * Public Types