net: inet_diag -- Return error code if protocol handler is missed

We've observed that in case if UDP diag module is not supported in kernel the netlink returns NLMSG_DONE without notifying a caller that handler is missed. This patch makes __inet_diag_dump to return error code instead. So as example it become possible to detect such situation and handle it gracefully on userspace level. Signed-off-by: Cyrill Gorcunov <[email protected]> CC: David Miller <[email protected]> CC: Eric Dumazet <[email protected]> CC: Pavel Emelyanov <[email protected]> Acked-by: Pavel Emelyanov <[email protected]> Signed-off-by: David S. Miller <[email protected]>
Wii-Linux · Nov 4, 2012 · cacb6ba · cacb6ba
1 parent efc7ce0
commit cacb6ba
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
@@ -892,13 +892,16 @@ static int __inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 		struct inet_diag_req_v2 *r, struct nlattr *bc)
 {
 	const struct inet_diag_handler *handler;
+	int err = 0;
 
 	handler = inet_diag_lock_handler(r->sdiag_protocol);
 	if (!IS_ERR(handler))
 		handler->dump(skb, cb, r, bc);
+	else
+		err = PTR_ERR(handler);
 	inet_diag_unlock_handler(handler);
 
-	return skb->len;
+	return err ? : skb->len;
 }
 
 static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)