diff --git a/include/linux/sockios.h b/include/linux/sockios.h
index 241f179347d9..7997a506ad41 100644
--- a/include/linux/sockios.h
+++ b/include/linux/sockios.h
@@ -22,7 +22,7 @@
 
 /* Linux-specific socket ioctls */
 #define SIOCINQ		FIONREAD
-#define SIOCOUTQ	TIOCOUTQ
+#define SIOCOUTQ	TIOCOUTQ        /* output queue size (not sent + not acked) */
 
 /* Routing table calls. */
 #define SIOCADDRT	0x890B		/* add routing table entry	*/
@@ -83,6 +83,8 @@
 
 #define SIOCWANDEV	0x894A		/* get/set netdev parameters	*/
 
+#define SIOCOUTQNSD	0x894B		/* output queue size (not sent only) */
+
 /* ARP cache control calls. */
 		    /*  0x8950 - 0x8952  * obsolete calls, don't re-use */
 #define SIOCDARP	0x8953		/* delete ARP table entry	*/
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a17a5a72b98d..b22d45010545 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -505,6 +505,15 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 		else
 			answ = tp->write_seq - tp->snd_una;
 		break;
+	case SIOCOUTQNSD:
+		if (sk->sk_state == TCP_LISTEN)
+			return -EINVAL;
+
+		if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
+			answ = 0;
+		else
+			answ = tp->write_seq - tp->snd_nxt;
+		break;
 	default:
 		return -ENOIOCTLCMD;
 	}