* [PATCH] tcp: restore rcv_wscale in a repair mode (v2)
@ 2012-09-19 19:40 Andrew Vagin
2012-09-20 9:31 ` Pavel Emelyanov
2012-09-20 21:50 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Andrew Vagin @ 2012-09-19 19:40 UTC (permalink / raw)
To: netdev
Cc: linux-kernel, Andrew Vagin, David S. Miller, Alexey Kuznetsov,
James Morris, Hideaki YOSHIFUJI, Patrick McHardy, Pavel Emelyanov
rcv_wscale is a symetric parameter with snd_wscale.
Both this parameters are set on a connection handshake.
Without this value a remote window size can not be interpreted correctly,
because a value from a packet should be shifted on rcv_wscale.
And one more thing is that wscale_ok should be set too.
This patch doesn't break a backward compatibility.
If someone uses it in a old scheme, a rcv window
will be restored with the same bug (rcv_wscale = 0).
v2: Save backward compatibility on big-endian system. Before
the first two bytes were snd_wscale and the second two bytes were
rcv_wscale. Now snd_wscale is opt_val & 0xFFFF and rcv_wscale >> 16.
This approach is independent on byte ordering.
Cc: David S. Miller <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
CC: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Vagin <avagin@openvz.org>
---
net/ipv4/tcp.c | 13 ++++++++++---
1 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index df83d74..42689aa 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2348,10 +2348,17 @@ static int tcp_repair_options_est(struct tcp_sock *tp,
tp->rx_opt.mss_clamp = opt.opt_val;
break;
case TCPOPT_WINDOW:
- if (opt.opt_val > 14)
- return -EFBIG;
+ {
+ u16 snd_wscale = opt.opt_val & 0xFFFF;
+ u16 rcv_wscale = opt.opt_val >> 16;
+
+ if (snd_wscale > 14 || rcv_wscale > 14)
+ return -EFBIG;
- tp->rx_opt.snd_wscale = opt.opt_val;
+ tp->rx_opt.snd_wscale = snd_wscale;
+ tp->rx_opt.rcv_wscale = rcv_wscale;
+ tp->rx_opt.wscale_ok = 1;
+ }
break;
case TCPOPT_SACK_PERM:
if (opt.opt_val != 0)
--
1.7.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] tcp: restore rcv_wscale in a repair mode (v2)
2012-09-19 19:40 [PATCH] tcp: restore rcv_wscale in a repair mode (v2) Andrew Vagin
@ 2012-09-20 9:31 ` Pavel Emelyanov
2012-09-20 21:50 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Pavel Emelyanov @ 2012-09-20 9:31 UTC (permalink / raw)
To: David S. Miller
Cc: Andrew Vagin, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Alexey Kuznetsov, James Morris,
Hideaki YOSHIFUJI, Patrick McHardy
On 09/19/2012 11:40 PM, Andrew Vagin wrote:
> rcv_wscale is a symetric parameter with snd_wscale.
>
> Both this parameters are set on a connection handshake.
>
> Without this value a remote window size can not be interpreted correctly,
> because a value from a packet should be shifted on rcv_wscale.
>
> And one more thing is that wscale_ok should be set too.
>
> This patch doesn't break a backward compatibility.
> If someone uses it in a old scheme, a rcv window
> will be restored with the same bug (rcv_wscale = 0).
>
> v2: Save backward compatibility on big-endian system. Before
> the first two bytes were snd_wscale and the second two bytes were
> rcv_wscale. Now snd_wscale is opt_val & 0xFFFF and rcv_wscale >> 16.
> This approach is independent on byte ordering.
>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
> Cc: James Morris <jmorris@namei.org>
> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
> Cc: Patrick McHardy <kaber@trash.net>
> CC: Pavel Emelyanov <xemul@parallels.com>
> Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tcp: restore rcv_wscale in a repair mode (v2)
2012-09-19 19:40 [PATCH] tcp: restore rcv_wscale in a repair mode (v2) Andrew Vagin
2012-09-20 9:31 ` Pavel Emelyanov
@ 2012-09-20 21:50 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2012-09-20 21:50 UTC (permalink / raw)
To: avagin; +Cc: netdev, linux-kernel, kuznet, jmorris, yoshfuji, kaber, xemul
From: Andrew Vagin <avagin@openvz.org>
Date: Wed, 19 Sep 2012 23:40:00 +0400
> rcv_wscale is a symetric parameter with snd_wscale.
>
> Both this parameters are set on a connection handshake.
>
> Without this value a remote window size can not be interpreted correctly,
> because a value from a packet should be shifted on rcv_wscale.
>
> And one more thing is that wscale_ok should be set too.
>
> This patch doesn't break a backward compatibility.
> If someone uses it in a old scheme, a rcv window
> will be restored with the same bug (rcv_wscale = 0).
>
> v2: Save backward compatibility on big-endian system. Before
> the first two bytes were snd_wscale and the second two bytes were
> rcv_wscale. Now snd_wscale is opt_val & 0xFFFF and rcv_wscale >> 16.
> This approach is independent on byte ordering.
>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
> Cc: James Morris <jmorris@namei.org>
> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
> Cc: Patrick McHardy <kaber@trash.net>
> CC: Pavel Emelyanov <xemul@parallels.com>
> Signed-off-by: Andrew Vagin <avagin@openvz.org>
Applied, thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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