aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux
diff options
context:
space:
mode:
authorHerbert Xu <herbert@gondor.apana.org.au>2005-10-03 16:57:23 -0400
committerDavid S. Miller <davem@davemloft.net>2005-10-03 16:57:23 -0400
commit325ed8239309cb29f10ea58c5a668058ead11479 (patch)
tree77386825b72ac44f4f42a942ef78bd1ff924b351 /include/linux
parentddea7be0ec8d1374f0b483a81566ed56ec9f3905 (diff)
[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 'include/linux')
-rw-r--r--include/linux/skbuff.h12
1 files changed, 3 insertions, 9 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2741c0c55e83..466c879f82b8 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -155,8 +155,6 @@ struct skb_shared_info {
155#define SKB_DATAREF_SHIFT 16 155#define SKB_DATAREF_SHIFT 16
156#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1) 156#define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1)
157 157
158extern struct timeval skb_tv_base;
159
160struct skb_timeval { 158struct skb_timeval {
161 u32 off_sec; 159 u32 off_sec;
162 u32 off_usec; 160 u32 off_usec;
@@ -175,7 +173,7 @@ enum {
175 * @prev: Previous buffer in list 173 * @prev: Previous buffer in list
176 * @list: List we are on 174 * @list: List we are on
177 * @sk: Socket we are owned by 175 * @sk: Socket we are owned by
178 * @tstamp: Time we arrived stored as offset to skb_tv_base 176 * @tstamp: Time we arrived
179 * @dev: Device we arrived on/are leaving by 177 * @dev: Device we arrived on/are leaving by
180 * @input_dev: Device we arrived on 178 * @input_dev: Device we arrived on
181 * @h: Transport layer header 179 * @h: Transport layer header
@@ -1255,10 +1253,6 @@ static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *
1255{ 1253{
1256 stamp->tv_sec = skb->tstamp.off_sec; 1254 stamp->tv_sec = skb->tstamp.off_sec;
1257 stamp->tv_usec = skb->tstamp.off_usec; 1255 stamp->tv_usec = skb->tstamp.off_usec;
1258 if (skb->tstamp.off_sec) {
1259 stamp->tv_sec += skb_tv_base.tv_sec;
1260 stamp->tv_usec += skb_tv_base.tv_usec;
1261 }
1262} 1256}
1263 1257
1264/** 1258/**
@@ -1272,8 +1266,8 @@ static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *
1272 */ 1266 */
1273static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp) 1267static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp)
1274{ 1268{
1275 skb->tstamp.off_sec = stamp->tv_sec - skb_tv_base.tv_sec; 1269 skb->tstamp.off_sec = stamp->tv_sec;
1276 skb->tstamp.off_usec = stamp->tv_usec - skb_tv_base.tv_usec; 1270 skb->tstamp.off_usec = stamp->tv_usec;
1277} 1271}
1278 1272
1279extern void __net_timestamp(struct sk_buff *skb); 1273extern void __net_timestamp(struct sk_buff *skb);