| From | Greg Kroah-Hartman <> | Subject | [ 46/66] tcp: fix FIONREAD/SIOCINQ | Date | Wed, 14 Nov 2012 20:10:51 -0800 |
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3.6-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ipv4/tcp.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
--- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -548,14 +548,12 @@ int tcp_ioctl(struct sock *sk, int cmd, !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);
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