[NET]: Fix packet timestamping.

I've found the problem in general.  It affects any 64-bit
architecture.  The problem occurs when you change the system time.

Suppose that when you boot your system clock is forward by a day.
This gets recorded down in skb_tv_base.  You then wind the clock back
by a day.  From that point onwards the offset will be negative which
essentially overflows the 32-bit variables they're stored in.

In fact, why don't we just store the real time stamp in those 32-bit
variables? After all, we're not going to overflow for quite a while
yet.

When we do overflow, we'll need a better solution of course.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 6a67a87384cc..499ae3df4a44 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -654,8 +654,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packe
                 __net_timestamp(skb);
                 sock_enable_timestamp(sk);
         }
-        h->tp_sec = skb_tv_base.tv_sec + skb->tstamp.off_sec;
-        h->tp_usec = skb_tv_base.tv_usec + skb->tstamp.off_usec;
+        h->tp_sec = skb->tstamp.off_sec;
+        h->tp_usec = skb->tstamp.off_usec;
 
         sll = (struct sockaddr_ll*)((u8*)h + TPACKET_ALIGN(sizeof(*h)));
         sll->sll_halen = 0;