Otherwise, passing signed types causes automatic promotion of the
result of the subtractions as well, which is not what we want, as
these macros rely on unsigned 32-bit arithmetic.
The next patch introduces a ssize_t operand for SEQ_LE, illustrating
the issue.
Signed-off-by: Stefano Brivio
---
tcp_internal.h | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/tcp_internal.h b/tcp_internal.h
index 36c6533..c80ba40 100644
--- a/tcp_internal.h
+++ b/tcp_internal.h
@@ -18,10 +18,14 @@
sizeof(struct ipv6hdr), \
sizeof(uint32_t))
-#define SEQ_LE(a, b) ((b) - (a) < MAX_WINDOW)
-#define SEQ_LT(a, b) ((b) - (a) - 1 < MAX_WINDOW)
-#define SEQ_GE(a, b) ((a) - (b) < MAX_WINDOW)
-#define SEQ_GT(a, b) ((a) - (b) - 1 < MAX_WINDOW)
+#define SEQ_LE(a, b) \
+ ((uint32_t)(b) - (uint32_t)(a) < MAX_WINDOW)
+#define SEQ_LT(a, b) \
+ ((uint32_t)(b) - (uint32_t)(a) - 1 < MAX_WINDOW)
+#define SEQ_GE(a, b) \
+ ((uint32_t)(a) - (uint32_t)(b) < MAX_WINDOW)
+#define SEQ_GT(a, b) \
+ ((uint32_t)(a) - (uint32_t)(b) - 1 < MAX_WINDOW)
#define FIN (1 << 0)
#define SYN (1 << 1)
--
2.43.0