From mboxrd@z Thu Jan 1 00:00:00 1970 From: YOSHIFUJI Hideaki Subject: Re: [PATCH 1/4] kernel: time: Add current_nw_timestamp() for network timestamps Date: Thu, 25 Feb 2016 17:49:20 +0900 Message-ID: <56CEC010.1080506@miraclelinux.com> References: <1456384031-29244-1-git-send-email-deepa.kernel@gmail.com> <1456384031-29244-2-git-send-email-deepa.kernel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Cc: hideaki.yoshifuji@miraclelinux.com, arnd@arndb.de, John Stultz , Thomas Gleixner , "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy To: Deepa Dinamani , netdev@vger.kernel.org, y2038@lists.linaro.org Return-path: Received: from mail-pa0-f51.google.com ([209.85.220.51]:36763 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759389AbcBYIta (ORCPT ); Thu, 25 Feb 2016 03:49:30 -0500 Received: by mail-pa0-f51.google.com with SMTP id yy13so28683080pab.3 for ; Thu, 25 Feb 2016 00:49:30 -0800 (PST) In-Reply-To: <1456384031-29244-2-git-send-email-deepa.kernel@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Hi, Deepa Dinamani wrote: > ICMP timestamp messages and IP source route options require > timestamps to be in milliseconds modulo 24 hours from > midnight UTC format. > > Add a time function to support this. The function returns the > required timestamp in network byte order. > > The function also uses y2038 safe time functions and data > structures. > > Signed-off-by: Deepa Dinamani > Cc: John Stultz > Cc: Thomas Gleixner > Cc: "David S. Miller" > Cc: Alexey Kuznetsov > Cc: James Morris > Cc: Hideaki YOSHIFUJI > Cc: Patrick McHardy > --- > include/linux/ip.h | 2 ++ > include/linux/time64.h | 3 +++ > kernel/time/time.c | 26 ++++++++++++++++++++++++++ > 3 files changed, 31 insertions(+) > > diff --git a/include/linux/ip.h b/include/linux/ip.h > index 492bc65..edf923e 100644 > --- a/include/linux/ip.h > +++ b/include/linux/ip.h > @@ -34,4 +34,6 @@ static inline struct iphdr *ipip_hdr(const struct sk_buff *skb) > { > return (struct iphdr *)skb_transport_header(skb); > } > + > +extern __be32 current_nw_timestamp(void); > #endif /* _LINUX_IP_H */ > diff --git a/include/linux/time64.h b/include/linux/time64.h > index 367d5af..5b5db3b 100644 > --- a/include/linux/time64.h > +++ b/include/linux/time64.h > @@ -35,6 +35,9 @@ struct itimerspec64 { > #define NSEC_PER_SEC 1000000000L > #define FSEC_PER_SEC 1000000000000000LL > > +#define SECONDS_PER_DAY 86400 > +#define MSEC_PER_DAY (SECONDS_PER_DAY * MSEC_PER_SEC) > + > /* Located here for timespec[64]_valid_strict */ > #define TIME64_MAX ((s64)~((u64)1 << 63)) > #define KTIME_MAX ((s64)~((u64)1 << 63)) > diff --git a/kernel/time/time.c b/kernel/time/time.c > index 86751c6..6df15df 100644 > --- a/kernel/time/time.c > +++ b/kernel/time/time.c > @@ -245,6 +245,32 @@ struct timespec current_fs_time(struct super_block *sb) > EXPORT_SYMBOL(current_fs_time); > > /* > + * current_nw_timestamp - Return network time > + * > + * Return milliseconds since midnight in network byte order. > + */ > +__be32 current_nw_timestamp(void) > +{ > + u64 now; > + u32 secs; > + u32 msecs; > + struct timespec64 ts; > + > + ktime_get_ts64(&ts); > + > + /* Get secs since midnight. */ > + now = div_u64_rem(ts.tv_sec, SECONDS_PER_DAY, &secs); > + /* Convert to msecs. */ > + msecs = secs * MSEC_PER_SEC; > + /* Convert nsec to msec. */ > + msecs += (u32)ts.tv_nsec/NSEC_PER_MSEC; > + > + /* Convert to network byte order. */ > + return htons(msecs); > +} > +EXPORT_SYMBOL(current_nw_timestamp); > + > +/* > * Convert jiffies to milliseconds and back. > * > * Avoid unnecessary multiplications/divisions in the > Since net/ipv4/* are the only users, it is enough to put it in under net/ipv4/. -- Hideaki Yoshifuji Technical Division, MIRACLE LINUX CORPORATION