From 325ed8239309cb29f10ea58c5a668058ead11479 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 3 Oct 2005 13:57:23 -0700 Subject: [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 Signed-off-by: David S. Miller --- include/linux/skbuff.h | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) (limited to 'include') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 2741c0c55e8..466c879f82b 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -155,8 +155,6 @@ struct skb_shared_info { #define SKB_DATAREF_SHIFT 16 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1) -extern struct timeval skb_tv_base; - struct skb_timeval { u32 off_sec; u32 off_usec; @@ -175,7 +173,7 @@ enum { * @prev: Previous buffer in list * @list: List we are on * @sk: Socket we are owned by - * @tstamp: Time we arrived stored as offset to skb_tv_base + * @tstamp: Time we arrived * @dev: Device we arrived on/are leaving by * @input_dev: Device we arrived on * @h: Transport layer header @@ -1255,10 +1253,6 @@ static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval * { stamp->tv_sec = skb->tstamp.off_sec; stamp->tv_usec = skb->tstamp.off_usec; - if (skb->tstamp.off_sec) { - stamp->tv_sec += skb_tv_base.tv_sec; - stamp->tv_usec += skb_tv_base.tv_usec; - } } /** @@ -1272,8 +1266,8 @@ static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval * */ static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp) { - skb->tstamp.off_sec = stamp->tv_sec - skb_tv_base.tv_sec; - skb->tstamp.off_usec = stamp->tv_usec - skb_tv_base.tv_usec; + skb->tstamp.off_sec = stamp->tv_sec; + skb->tstamp.off_usec = stamp->tv_usec; } extern void __net_timestamp(struct sk_buff *skb); -- cgit v1.2.3