From da46fdac36058e97e5a3131e2c51d162f4c619e9 Mon Sep 17 00:00:00 2001
From: Stefano Brivio <sbrivio@redhat.com>
Date: Sat, 25 Feb 2023 12:09:01 +0100
Subject: tcp: Suppress knownConditionTrueFalse cppcheck false positive
cppcheck 2.10 reports:
tcp.c:1815:12: style: Condition 'wnd>prev_scaled' is always false [knownConditionTrueFalse]
if ((wnd > prev_scaled && wnd * 99 / 100 < prev_scaled) ||
^
tcp.c:1808:8: note: Assignment 'wnd=((1<<(16+8))<(wnd))?(1<<(16+8)):(wnd)', assigned value is less than 1
wnd = MIN(MAX_WINDOW, wnd);
^
tcp.c:1811:19: note: Assuming condition is false
if (prev_scaled == wnd)
^
tcp.c:1815:12: note: Condition 'wnd>prev_scaled' is always false
if ((wnd > prev_scaled && wnd * 99 / 100 < prev_scaled) ||
^
but this is not actually the case: wnd is typically greater than 1,
and might very well be greater than prev_scaled as well.
I bisected this down to cppcheck commit b4d455df487c ("Fix 11349: FP
negativeIndex for clamped array index (#4627)") and reported findings
at https://github.com/danmar/cppcheck/pull/4627.
Suppress the warning for the moment being.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
tcp.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/tcp.c b/tcp.c
index 803c2c4..21c319d 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1812,6 +1812,15 @@ static void tcp_clamp_window(const struct ctx *c, struct tcp_tap_conn *conn,
return;
/* Discard +/- 1% updates to spare some syscalls. */
+ /* TODO: cppcheck, starting from commit b4d455df487c ("Fix
+ * 11349: FP negativeIndex for clamped array index (#4627)"),
+ * reports wnd > prev_scaled as always being true, see also:
+ *
+ * https://github.com/danmar/cppcheck/pull/4627
+ *
+ * drop this suppression once that's resolved.
+ */
+ /* cppcheck-suppress knownConditionTrueFalse */
if ((wnd > prev_scaled && wnd * 99 / 100 < prev_scaled) ||
(wnd < prev_scaled && wnd * 101 / 100 > prev_scaled))
return;
--
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