From 325ed8239309cb29f10ea58c5a668058ead11479 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 3 Oct 2005 13:57:23 -0700 Subject: [PATCH] [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 +++--------- net/core/skbuff.c | 5 ----- net/ipv4/netfilter/ip_queue.c | 4 ++-- net/ipv4/netfilter/ipt_ULOG.c | 4 ++-- net/ipv6/netfilter/ip6_queue.c | 4 ++-- net/netfilter/nfnetlink_log.c | 4 ++-- net/netfilter/nfnetlink_queue.c | 4 ++-- net/packet/af_packet.c | 4 ++-- 8 files changed, 15 insertions(+), 26 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 2741c0c55e..466c879f82 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); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index f80a287856..0e9431b59f 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 @@ void __init skb_init(void) 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_prepare_seq_read); 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 d54f14d926..36339eb39e 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -240,8 +240,8 @@ ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp) 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 e2c14f3cb2..2883ccd8a9 100644 --- a/net/ipv4/netfilter/ipt_ULOG.c +++ b/net/ipv4/netfilter/ipt_ULOG.c @@ -225,8 +225,8 @@ static void ipt_ulog_packet(unsigned int hooknum, /* 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 aa11cf366e..5027bbe641 100644 --- a/net/ipv6/netfilter/ip6_queue.c +++ b/net/ipv6/netfilter/ip6_queue.c @@ -238,8 +238,8 @@ ipq_build_packet_message(struct ipq_queue_entry *entry, int *errp) 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 ff5601ceed..efcd10f996 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -494,8 +494,8 @@ __build_packet_message(struct nfulnl_instance *inst, 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 f81fe8c52e..eaa44c4956 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -492,8 +492,8 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue, 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 6a67a87384..499ae3df4a 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; -- 2.39.5