[NET]: convert network timestamps to ktime_t

We currently use a special structure (struct skb_timeval) and plain
'struct timeval' to store packet timestamps in sk_buffs and struct
sock.

This has some drawbacks :
- Fixed resolution of micro second.
- Waste of space on 64bit platforms where sizeof(struct timeval)=16

I suggest using ktime_t that is a nice abstraction of high resolution
time services, currently capable of nanosecond resolution.

As sizeof(ktime_t) is 8 bytes, using ktime_t in 'struct sock' permits
a 8 byte shrink of this structure on 64bit architectures. Some other
structures also benefit from this size reduction (struct ipq in
ipv4/ip_fragment.c, struct frag_queue in ipv6/reassembly.c, ...)

Once this ktime infrastructure adopted, we can more easily provide
nanosecond resolution on top of it. (ioctl SIOCGSTAMPNS and/or
SO_TIMESTAMPNS/SCM_TIMESTAMPNS)

Note : this patch includes a bug correction in
compat_sock_get_timestamp() where a "err = 0;" was missing (so this
syscall returned -ENOENT instead of 0)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
CC: Stephen Hemminger <shemminger@linux-foundation.org>
CC: John find <linux.kernel@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 5 deletions

diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index a14798a850d7..5842f1aa973a 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -197,6 +197,7 @@ ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 	struct sk_buff *skb;
 	struct ipq_packet_msg *pmsg;
 	struct nlmsghdr *nlh;
+	struct timeval tv;
 
 	read_lock_bh(&queue_lock);
 
@@ -241,8 +242,9 @@ ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp)
 
 	pmsg->packet_id       = (unsigned long )entry;
 	pmsg->data_len        = data_len;
-	pmsg->timestamp_sec   = entry->skb->tstamp.off_sec;
-	pmsg->timestamp_usec  = entry->skb->tstamp.off_usec;
+	tv = ktime_to_timeval(entry->skb->tstamp);
+	pmsg->timestamp_sec   = tv.tv_sec;
+	pmsg->timestamp_usec  = tv.tv_usec;
 	pmsg->mark            = entry->skb->mark;
 	pmsg->hook            = entry->info->hook;
 	pmsg->hw_protocol     = entry->skb->protocol;
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
index 9acc018766f2..9718b666a380 100644
--- a/net/ipv4/netfilter/ipt_ULOG.c
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -187,6 +187,7 @@ static void ipt_ulog_packet(unsigned int hooknum,
 	ulog_packet_msg_t *pm;
 	size_t size, copy_len;
 	struct nlmsghdr *nlh;
+	struct timeval tv;
 
 	/* ffs == find first bit set, necessary because userspace
 	 * is already shifting groupnumber, but we need unshifted.
@@ -232,13 +233,14 @@ static void ipt_ulog_packet(unsigned int hooknum,
 	pm = NLMSG_DATA(nlh);
 
 	/* We might not have a timestamp, get one */
-	if (skb->tstamp.off_sec == 0)
+	if (skb->tstamp.tv64 == 0)
 		__net_timestamp((struct sk_buff *)skb);
 
 	/* copy hook, prefix, timestamp, payload, etc. */
 	pm->data_len = copy_len;
-	put_unaligned(skb->tstamp.off_sec, &pm->timestamp_sec);
-	put_unaligned(skb->tstamp.off_usec, &pm->timestamp_usec);
+	tv = ktime_to_timeval(skb->tstamp);
+	put_unaligned(tv.tv_sec, &pm->timestamp_sec);
+	put_unaligned(tv.tv_usec, &pm->timestamp_usec);
 	put_unaligned(skb->mark, &pm->mark);
 	pm->hook = hooknum;
 	if (prefix != NULL)