Alex Sidorenko wrote:
[snip]
--- net/ipv4/tcp_output.c.orig Wed May 3 20:40:43 2006
+++ net/ipv4/tcp_output.c Tue Jan 30 14:24:56 2007
@@ -641,6 +641,7 @@
* Note, we don't "adjust" for TIMESTAMP or SACK option bytes.
* Regular options like TIMESTAMP are taken into account.
*/
+static const char *SWS_id_string="@#SWS-fix-2";
u32 __tcp_select_window(struct sock *sk)
{
struct tcp_opt *tp = &sk->tp_pinfo.af_tcp;
@@ -682,6 +683,9 @@
window = tp->rcv_wnd;
if (window <= free_space - mss || window > free_space)
window = (free_space/mss)*mss;
+ /* A fix for small rcvbuf [EMAIL PROTECTED] */
+ else if (mss == full_space && window < full_space/2)
+ window = full_space/2;
return window;
}
Good analysis of the problem, but the patch does not look quite right.
In particular, you can't ever announce a zero window. :)
I think this attached patch does the correct SWS avoidance.
Thanks,
-John
Do receiver-side SWS avoidance for rcvbuf < MSS.
Signed-off-by: John Heffner <[EMAIL PROTECTED]>
---
commit 38d33181c93a28cf7fb2f9f3377305a04636c054
tree 503f8a9de6e78694bae9fc2eb1c9dd5d26a0b5ed
parent 562aa1d4c6a874373f9a48ac184f662fbbb06a04
author John Heffner <[EMAIL PROTECTED]> Fri, 02 Mar 2007 13:47:44 -0500
committer John Heffner <[EMAIL PROTECTED]> Fri, 02 Mar 2007 13:47:44 -0500
net/ipv4/tcp_output.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index dc15113..688b955 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1607,6 +1607,9 @@ u32 __tcp_select_window(struct sock *sk)
*/
if (window <= free_space - mss || window > free_space)
window = (free_space/mss)*mss;
+ else if (mss == full_space &&
+ free_space > window + full_space/2)
+ window = free_space;
}
return window;
