[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>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2741c0c..466c879 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -155,8 +155,6 @@
#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 @@
* @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 @@
{
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_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);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index f80a287..0e9431b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -71,8 +71,6 @@
static kmem_cache_t *skbuff_head_cache __read_mostly;
static kmem_cache_t *skbuff_fclone_cache __read_mostly;
-struct timeval __read_mostly skb_tv_base;
-
/*
* Keep out-of-line to prevent kernel bloat.
* __builtin_return_address is not used because it is not always
@@ -1708,8 +1706,6 @@
NULL, NULL);
if (!skbuff_fclone_cache)
panic("cannot create skbuff cache");
-
- do_gettimeofday(&skb_tv_base);
}
EXPORT_SYMBOL(___pskb_trim);
@@ -1743,4 +1739,3 @@
EXPORT_SYMBOL(skb_seq_read);
EXPORT_SYMBOL(skb_abort_seq_read);
EXPORT_SYMBOL(skb_find_text);
-EXPORT_SYMBOL(skb_tv_base);
diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index d54f14d..36339eb 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -240,8 +240,8 @@
pmsg->packet_id = (unsigned long )entry;
pmsg->data_len = data_len;
- pmsg->timestamp_sec = skb_tv_base.tv_sec + entry->skb->tstamp.off_sec;
- pmsg->timestamp_usec = skb_tv_base.tv_usec + entry->skb->tstamp.off_usec;
+ pmsg->timestamp_sec = entry->skb->tstamp.off_sec;
+ pmsg->timestamp_usec = entry->skb->tstamp.off_usec;
pmsg->mark = entry->skb->nfmark;
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 e2c14f3..2883ccd 100644
--- a/net/ipv4/netfilter/ipt_ULOG.c
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -225,8 +225,8 @@
/* copy hook, prefix, timestamp, payload, etc. */
pm->data_len = copy_len;
- pm->timestamp_sec = skb_tv_base.tv_sec + skb->tstamp.off_sec;
- pm->timestamp_usec = skb_tv_base.tv_usec + skb->tstamp.off_usec;
+ pm->timestamp_sec = skb->tstamp.off_sec;
+ pm->timestamp_usec = skb->tstamp.off_usec;
pm->mark = skb->nfmark;
pm->hook = hooknum;
if (prefix != NULL)
diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c
index aa11cf3..5027bbe 100644
--- a/net/ipv6/netfilter/ip6_queue.c
+++ b/net/ipv6/netfilter/ip6_queue.c
@@ -238,8 +238,8 @@
pmsg->packet_id = (unsigned long )entry;
pmsg->data_len = data_len;
- pmsg->timestamp_sec = skb_tv_base.tv_sec + entry->skb->tstamp.off_sec;
- pmsg->timestamp_usec = skb_tv_base.tv_usec + entry->skb->tstamp.off_usec;
+ pmsg->timestamp_sec = entry->skb->tstamp.off_sec;
+ pmsg->timestamp_usec = entry->skb->tstamp.off_usec;
pmsg->mark = entry->skb->nfmark;
pmsg->hook = entry->info->hook;
pmsg->hw_protocol = entry->skb->protocol;
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index ff5601c..efcd10f 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -494,8 +494,8 @@
if (skb->tstamp.off_sec) {
struct nfulnl_msg_packet_timestamp ts;
- ts.sec = cpu_to_be64(skb_tv_base.tv_sec + skb->tstamp.off_sec);
- ts.usec = cpu_to_be64(skb_tv_base.tv_usec + skb->tstamp.off_usec);
+ ts.sec = cpu_to_be64(skb->tstamp.off_sec);
+ ts.usec = cpu_to_be64(skb->tstamp.off_usec);
NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
}
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index f81fe8c..eaa44c4 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -492,8 +492,8 @@
if (entry->skb->tstamp.off_sec) {
struct nfqnl_msg_packet_timestamp ts;
- ts.sec = cpu_to_be64(skb_tv_base.tv_sec + entry->skb->tstamp.off_sec);
- ts.usec = cpu_to_be64(skb_tv_base.tv_usec + entry->skb->tstamp.off_usec);
+ ts.sec = cpu_to_be64(entry->skb->tstamp.off_sec);
+ ts.usec = cpu_to_be64(entry->skb->tstamp.off_usec);
NFA_PUT(skb, NFQA_TIMESTAMP, sizeof(ts), &ts);
}
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 6a67a87..499ae3d 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -654,8 +654,8 @@
__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;
