tcp: ioctl type SIOCOUTQNSD returns amount of data not sent
In contrast to SIOCOUTQ which returns the amount of data sent
but not yet acknowledged plus data not yet sent this patch only
returns the data not sent.
For various methods of live streaming bitrate control it may
be helpful to know how much data are in the tcp outqueue are
not sent yet.
Signed-off-by: Mario Schuknecht <m.schuknecht@dresearch.de>
Signed-off-by: Steffen Sledz <sledz@dresearch.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a17a5a7..b22d450 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -505,6 +505,15 @@
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;
}