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authorEric Dumazet <edumazet@google.com>2012-10-18 09:14:12 +0000
committerBen Hutchings <ben@decadent.org.uk>2012-11-16 16:47:15 +0000
commite8c9f482ed9dc59f3747a065e497854ddd174e60 (patch)
treee192f7be5f840d0a6aedbc2473969812d809bc00 /net/ipv4
parent9e4ac2075cbf126be9e37762c8c1c6aec714dcc5 (diff)
tcp: fix FIONREAD/SIOCINQ
[ Upstream commit a3374c42aa5f7237e87ff3b0622018636b0c847e ] tcp_ioctl() tries to take into account if tcp socket received a FIN to report correct number bytes in receive queue. But its flaky because if the application ate the last skb, we return 1 instead of 0. Correct way to detect that FIN was received is to test SOCK_DONE. Reported-by: Elliot Hughes <enh@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 7397ad806f4c..52edbb837e1f 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -481,14 +481,12 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
!tp->urg_data ||
before(tp->urg_seq, tp->copied_seq) ||
!before(tp->urg_seq, tp->rcv_nxt)) {
- struct sk_buff *skb;
answ = tp->rcv_nxt - tp->copied_seq;
- /* Subtract 1, if FIN is in queue. */
- skb = skb_peek_tail(&sk->sk_receive_queue);
- if (answ && skb)
- answ -= tcp_hdr(skb)->fin;
+ /* Subtract 1, if FIN was received */
+ if (answ && sock_flag(sk, SOCK_DONE))
+ answ--;
} else
answ = tp->urg_seq - tp->copied_seq;
release_sock(sk);