[056/152] tcp: Bug fix in initialization of receive window.

Greg KH
2011-01-06T00:52:33Z

From: Nandita Dukkipati <nanditad@google.com>

[ Upstream commit b1afde60f2b9ee8444fba4e012dc99a3b28d224d ]

The bug has to do with boundary checks on the initial receive window.
If the initial receive window falls between init_cwnd and the
receive window specified by the user, the initial window is incorrectly
brought down to init_cwnd. The correct behavior is to allow it to
remain unchanged.

Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/ipv4/tcp_output.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -237,11 +237,10 @@ void tcp_select_initial_window(int __spa
/* when initializing use the value from init_rcv_wnd
* rather than the default from above
*/
- if (init_rcv_wnd &&
- (*rcv_wnd > init_rcv_wnd * mss))
- *rcv_wnd = init_rcv_wnd * mss;
- else if (*rcv_wnd > init_cwnd * mss)
- *rcv_wnd = init_cwnd * mss;
+ if (init_rcv_wnd)
+ *rcv_wnd = min(*rcv_wnd, init_rcv_wnd * mss);
+ else
+ *rcv_wnd = min(*rcv_wnd, init_cwnd * mss);
}

/* Set the clamp no higher than max representable value */