unix_diag: Receive queue lenght NLA

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/unix_diag.h

@@ -15,6 +15,7 @@ struct unix_diag_req {
 #define UDIAG_SHOW_VFS		0x00000002	/* show VFS inode info */
 #define UDIAG_SHOW_PEER		0x00000004	/* show peer socket info */
 #define UDIAG_SHOW_ICONS	0x00000008	/* show pending connections */
+#define UDIAG_SHOW_RQLEN	0x00000010	/* show skb receive queue len */
 
 struct unix_diag_msg {
 	__u8	udiag_family;
@@ -31,6 +32,7 @@ enum {
 	UNIX_DIAG_VFS,
 	UNIX_DIAG_PEER,
 	UNIX_DIAG_ICONS,
+	UNIX_DIAG_RQLEN,
 
 	UNIX_DIAG_MAX,
 };

net/unix/diag.c

@@ -98,6 +98,15 @@ static int sk_diag_dump_icons(struct sock *sk, struct sk_buff *nlskb)
 	return -EMSGSIZE;
 }
 
+static int sk_diag_show_rqlen(struct sock *sk, struct sk_buff *nlskb)
+{
+	RTA_PUT_U32(nlskb, UNIX_DIAG_RQLEN, sk->sk_receive_queue.qlen);
+	return 0;
+
+rtattr_failure:
+	return -EMSGSIZE;
+}
+
 static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
 		u32 pid, u32 seq, u32 flags, int sk_ino)
 {
@@ -132,6 +141,10 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_r
 			sk_diag_dump_icons(sk, skb))
 		goto nlmsg_failure;
 
+	if ((req->udiag_show & UDIAG_SHOW_RQLEN) &&
+			sk_diag_show_rqlen(sk, skb))
+		goto nlmsg_failure;
+
 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 	return skb->len;