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authorNeil Spring2021-08-25 14:01:17 -0700
committerJakub Kicinski2021-08-26 18:00:40 -0700
commit3aa7857fe1d7ac7f600f5b7e1530396fb06822bf (patch)
tree2cc8e7ad1346e14878e66f4bdddadd2df910103f /net
parent97c78d0af55fff206947a5f2b85b690b5acf28ce (diff)
tcp: enable mid stream window clamp
The TCP_WINDOW_CLAMP socket option is defined in tcp(7) to "Bound the size of the advertised window to this value." Window clamping is distributed across two variables, window_clamp ("Maximal window to advertise" in tcp.h) and rcv_ssthresh ("Current window clamp"). This patch updates the function where the window clamp is set to also reduce the current window clamp, rcv_sshthresh, if needed. With this, setting the TCP_WINDOW_CLAMP option has the documented effect of limiting the window. Signed-off-by: Neil Spring <ntspring@fb.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20210825210117.1668371-1-ntspring@fb.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f931def6302e..e8b48df73c85 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3338,6 +3338,7 @@ int tcp_set_window_clamp(struct sock *sk, int val)
} else {
tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
SOCK_MIN_RCVBUF / 2 : val;
+ tp->rcv_ssthresh = min(tp->rcv_wnd, tp->window_clamp);
}
return 0;
}