From: Nandita Dukkipati <nanditad@google.com>
Date: Fri, 3 Dec 2010 13:33:44 +0000 (+0000)
Subject: tcp: Bug fix in initialization of receive window.
X-Git-Tag: firefly_0821_release~9833^2~71^2^2~96
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=dea96398b30bf6b5d966a9133d0ad30cd1aa946b;p=firefly-linux-kernel-4.4.55.git

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>
---

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index de3bd8458588..ea3983835872 100644
--- 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 */