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| author | Stefano Brivio <sbrivio@redhat.com> | 2025-02-11 20:11:00 +0100 |
|---|---|---|
| committer | Stefano Brivio <sbrivio@redhat.com> | 2025-02-12 19:34:15 +0100 |
| commit | 472e2e930f6e17d9d8664d6cf44c47af1db58bb3 (patch) | |
| tree | 21fea8f37fb543ea6739428daffe59903ab96d4e /vu_common.c | |
| parent | 31e8109a86eeebb473ffba8124a3f399cf0aeccf (diff) | |
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tcp: Don't discard window information on keep-alive segments
It looks like a detail, but it's critical if we're dealing with
somebody, such as near-future self, using TCP_REPAIR to migrate TCP
connections in the guest or container.
The last packet sent from the 'source' process/guest/container
typically reports a small window, or zero, because the guest/container
hadn't been draining it for a while.
The next packet, appearing as the target sets TCP_REPAIR_OFF on the
migrated socket, is a keep-alive (also called "window probe" in CRIU
or TCP_REPAIR-related code), and it comes with an updated window
value, reflecting the pre-migration "regular" value.
If we ignore it, it might take a while/forever before we realise we
can actually restart sending.
Fixes: 238c69f9af45 ("tcp: Acknowledge keep-alive segments, ignore them for the rest")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'vu_common.c')
0 files changed, 0 insertions, 0 deletions