tcp: Bug fix in initialization of receive window.

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>

1 files changed, 4 insertions, 5 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 05b1ecf36763..3c59ab42df2b 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -231,11 +231,10 @@ void tcp_select_initial_window(int __space, __u32 mss,
                 /* 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 */