From cacb6ba0f36ab14a507f4ee7697e8332899015d2 Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov@openvz.org>
Date: Sat, 3 Nov 2012 09:30:34 +0000
Subject: [PATCH] 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 <gorcunov@openvz.org>
CC: David Miller <davem@davemloft.net>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/inet_diag.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 535584c00f91..0c34bfabc11f 100644
--- 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)
--
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