[PATCH nft] statement: Avoid rounding bytes in get_rate()

[PATCH nft] statement: Avoid rounding bytes in get_rate()

[Elise Lennion]

get_rate() is used to print quotas and limits and currently rounds the
number of bytes:

$ nft add quota filter https-quota 4000 kbytes
$ nft list ruleset
table ip filter {
	quota https-quota {
		3 mbytes
	}
}

This may be a problem when loading your configuration after saving it
with 'list ruleset'. With this patch the values are represented in a
greater unit only when there is no rest in the conversion:

$ nft add quota filter https-quota2 2048 kbytes
$ nft list ruleset
table ip filter {
	quota https-quota {
		4000 kbytes
	}

	quota https-quota2 {
		2 mbytes
	}
}

Signed-off-by: Elise Lennion <elise.lennion@gmail.com>
---
 src/statement.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/src/statement.c b/src/statement.c
index 3beb86a..7ffd25f 100644
--- a/src/statement.c
+++ b/src/statement.c
@@ -300,20 +300,15 @@ static const char *data_unit[] = {
 
 const char *get_rate(uint64_t byte_rate, uint64_t *rate)
 {
-	uint64_t res, prev, rest;
 	int i;
 
-	res = prev = byte_rate;
-	for (i = 0;; i++) {
-		rest = res % 1024;
-		res /= 1024;
-		if (res <= 1 && rest != 0)
+	for (i = 0; data_unit[i + 1] != NULL; i++) {
+		if (byte_rate % 1024)
 			break;
-		if (data_unit[i + 1] == NULL)
-			break;
-		prev = res;
+		byte_rate /= 1024;
 	}
-	*rate = prev;
+
+	*rate = byte_rate;
 	return data_unit[i];
 }
 
-- 
2.7.4

Re: [PATCH nft] statement: Avoid rounding bytes in get_rate()

[Pablo Neira Ayuso]

On Sun, Feb 12, 2017 at 10:45:34AM -0200, Elise Lennion wrote:
> get_rate() is used to print quotas and limits and currently rounds the
> number of bytes:
> 
> $ nft add quota filter https-quota 4000 kbytes
> $ nft list ruleset
> table ip filter {
> 	quota https-quota {
> 		3 mbytes
> 	}
> }
> 
> This may be a problem when loading your configuration after saving it
> with 'list ruleset'. With this patch the values are represented in a
> greater unit only when there is no rest in the conversion:
> 
> $ nft add quota filter https-quota2 2048 kbytes
> $ nft list ruleset
> table ip filter {
> 	quota https-quota {
> 		4000 kbytes
> 	}
> 
> 	quota https-quota2 {
> 		2 mbytes
> 	}
> }

also applied, thanks Elise.