1 files changed, 9 insertions, 0 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a17a5a72b98..b22d4501054 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;
         }