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| author |   Andrey Vagin <avagin@openvz.org> | 2016-06-27 15:33:56 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2016-06-30 08:15:31 -0400 |
| commit | b1ed4c4fa9a5ccf325184fd90edc50978ef6e33a (patch) | |
| tree | eb298a85a5f016c52ad375f351bf171eec99152a /include/uapi | |
| parent | Merge branch 'bridge-igmp-stats' (diff) | |
| download | linux-dev-b1ed4c4fa9a5ccf325184fd90edc50978ef6e33a.tar.xz linux-dev-b1ed4c4fa9a5ccf325184fd90edc50978ef6e33a.zip | |
tcp: add an ability to dump and restore window parameters
We found that sometimes a restored tcp socket doesn't work.
A reason of this bug is incorrect window parameters and in this case
tcp_acceptable_seq() returns tcp_wnd_end(tp) instead of tp->snd_nxt. The
other side drops packets with this seq, because seq is less than
tp->rcv_nxt ( tcp_sequence() ).
Data from a send queue is sent only if there is enough space in a
window, so when we restore unacked data, we need to expand a window to
fit this data.
This was in a first version of this patch:
"tcp: extend window to fit all restored unacked data in a send queue"
Then Alexey recommended me to restore window parameters instead of
adjusted them according with data in a sent queue. This sounds resonable.
rcv_wnd has to be restored, because it was reported to another side
and the offered window is never shrunk.
One of reasons why we need to restore snd_wnd was described above.
Cc: Pavel Emelyanov <xemul@parallels.com>
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>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/tcp.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 53e8e3fe6b1b..482898fc433a 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -115,12 +115,22 @@ enum { #define TCP_CC_INFO 26 /* Get Congestion Control (optional) info */ #define TCP_SAVE_SYN 27 /* Record SYN headers for new connections */ #define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */ +#define TCP_REPAIR_WINDOW 29 /* Get/set window parameters */ struct tcp_repair_opt { __u32 opt_code; __u32 opt_val; }; +struct tcp_repair_window { + __u32 snd_wl1; + __u32 snd_wnd; + __u32 max_window; + + __u32 rcv_wnd; + __u32 rcv_wup; +}; + enum { TCP_NO_QUEUE, TCP_RECV_QUEUE, |