From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH v2 iproute2] get_rate: detect 32bit overflows Date: Mon, 03 Jun 2013 08:51:33 -0700 Message-ID: <1370274693.24311.154.camel@edumazet-glaptop> References: <1370199083.24311.43.camel@edumazet-glaptop> <1370209008.24311.91.camel@edumazet-glaptop> <1370270231.1918.10.camel@bwh-desktop.uk.level5networks.com> <1370272783.24311.148.camel@edumazet-glaptop> <1370273807.1918.20.camel@bwh-desktop.uk.level5networks.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Stephen Hemminger , netdev To: Ben Hutchings Return-path: Received: from mail-gh0-f178.google.com ([209.85.160.178]:36790 "EHLO mail-gh0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758778Ab3FCP6z (ORCPT ); Mon, 3 Jun 2013 11:58:55 -0400 Received: by mail-gh0-f178.google.com with SMTP id g15so244244ghb.37 for ; Mon, 03 Jun 2013 08:58:55 -0700 (PDT) In-Reply-To: <1370273807.1918.20.camel@bwh-desktop.uk.level5networks.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2013-06-03 at 16:36 +0100, Ben Hutchings wrote: > Oops, I read this as being strtol() currently, not strtod(). Currently > '1.5gbit' will work, but this change will break that. So I think you > need to keep bps as a double. Arg > Then here I think the check should be *rate != floor(bps), i.e. accept > rounding down of a non-integer number of bytes but any other change is > assumed to be overflow. Thanks Ben, here is v4 then ;) [PATCH v4] get_rate: detect 32bit overflows Current rate limit is 34.359.738.360 bit per second, and unfortunately 40Gbps links are above it. overflows in get_rate() are currently not detected, and some users are confused. Let's detect this and complain. Note that some qdisc are ready to get extended range, but this will need additional attributes and new iproute2 With help from Ben Hutchings Signed-off-by: Eric Dumazet --- tc/tc_util.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/tc/tc_util.c b/tc/tc_util.c index 8e62a01..8114c97 100644 --- a/tc/tc_util.c +++ b/tc/tc_util.c @@ -152,19 +152,23 @@ int get_rate(unsigned *rate, const char *str) if (p == str) return -1; - if (*p == '\0') { - *rate = bps / 8.; /* assume bits/sec */ - return 0; - } - for (s = suffixes; s->name; ++s) { if (strcasecmp(s->name, p) == 0) { - *rate = (bps * s->scale) / 8.; - return 0; + bps *= s->scale; + p += strlen(p); + break; } } - return -1; + if (*p) + return -1; /* unknown suffix */ + + bps /= 8; /* -> bytes per second */ + *rate = bps; + /* detect if an overflow happened */ + if (*rate != floor(bps)) + return -1; + return 0; } void print_rate(char *buf, int len, __u32 rate)