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authorHerbert Xu <herbert@gondor.apana.org.au>2005-10-03 22:57:23 +0200
committerDavid S. Miller <davem@davemloft.net>2005-10-03 22:57:23 +0200
commit325ed8239309cb29f10ea58c5a668058ead11479 (patch)
tree77386825b72ac44f4f42a942ef78bd1ff924b351 /net/packet
parent[PATCH] x86_64: Fix numa node topology detection for srat based x86_64 boxes (diff)
downloadlinux-325ed8239309cb29f10ea58c5a668058ead11479.tar.xz
linux-325ed8239309cb29f10ea58c5a668058ead11479.zip
[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>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c4
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;