tcp: Bug fix in initialization of receive window.

[ 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>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 7ed9dc1042d1930a7eb2107def30642cb367fa92..0c93b0b98b14f52b812af27120f12f9268ca6dcb 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -237,11 +237,10 @@ 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 */