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| author |   Andrey Vagin <avagin@openvz.org> | 2012-09-19 09:40:00 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2012-09-20 17:49:58 -0400 |
| commit | bc26ccd8fc756749de95606d28314efd0ce5aec3 (patch) | |
| tree | 7415996141c9777b09f0d33ca90283bc44a40632 /net | |
| parent | net/core: fix comment in skb_try_coalesce (diff) | |
| download | linux-dev-bc26ccd8fc756749de95606d28314efd0ce5aec3.tar.xz linux-dev-bc26ccd8fc756749de95606d28314efd0ce5aec3.zip | |
tcp: restore rcv_wscale in a repair mode (v2)
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | 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 bf9a8ab29459..5f6419341821 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2331,10 +2331,17 @@ 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) |