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authorAndrey Vagin <avagin@openvz.org>2012-09-19 13:40:00 +0400
committerDavid S. Miller <davem@davemloft.net>2012-09-21 01:49:58 +0400
commitbc26ccd8fc756749de95606d28314efd0ce5aec3 (patch)
tree7415996141c9777b09f0d33ca90283bc44a40632 /net/ipv4/tcp.c
parent8ea853fd0b721f14eacff1a5b364fe3e60d2dd82 (diff)
downloadlinux-bc26ccd8fc756749de95606d28314efd0ce5aec3.tar.xz
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/ipv4/tcp.c')
-rw-r--r--net/ipv4/tcp.c13
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)