[PATCH 1/4] kernel: time: Add current_nw_timestamp() for network timestamps
From: Deepa Dinamani <hidden>
Date: 2016-02-25 07:08:56
Subsystem:
the rest, timekeeping, clocksource core, ntp, alarmtimer · Maintainers:
Linus Torvalds, John Stultz, Thomas Gleixner
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 <redacted> Cc: John Stultz <redacted> Cc: Thomas Gleixner <redacted> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <redacted> Cc: James Morris <jmorris@namei.org> Cc: Hideaki YOSHIFUJI <redacted> Cc: Patrick McHardy <redacted> --- 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
--
1.9.1