Commit d93376f5 authored Mar 02, 2022 by Martin KaFai Lau Committed by David S. Miller Mar 03, 2022

net: Clear mono_delivery_time bit in __skb_tstamp_tx()



In __skb_tstamp_tx(), it may clone the egress skb and queues the clone to
the sk_error_queue.  The outgoing skb may have the mono delivery_time
while the (rcv) timestamp is expected for the clone, so the
skb->mono_delivery_time bit needs to be cleared from the clone.

This patch adds the skb->mono_delivery_time clearing to the existing
__net_timestamp() and use it in __skb_tstamp_tx().
The __net_timestamp() fast path usage in dev.c is changed to directly
call ktime_get_real() since the mono_delivery_time bit is not set at
that point.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 27942a15

include/linux/skbuff.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -3981,6 +3981,7 @@ static inline void skb_get_new_timestampns(const struct sk_buff *skb,
		static inline void __net_timestamp(struct sk_buff *skb)
		{
		skb->tstamp = ktime_get_real();
		skb->mono_delivery_time = 0;
		}

		static inline ktime_t net_timedelta(ktime_t t)

net/core/dev.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -2111,13 +2111,13 @@ static inline void net_timestamp_set(struct sk_buff *skb)
		skb->tstamp = 0;
		skb->mono_delivery_time = 0;
		if (static_branch_unlikely(&netstamp_needed_key))
		__net_timestamp(skb);
		skb->tstamp = ktime_get_real();
		}

		#define net_timestamp_check(COND, SKB) \
		if (static_branch_unlikely(&netstamp_needed_key)) { \
		if ((COND) && !(SKB)->tstamp) \
		__net_timestamp(SKB); \
		(SKB)->tstamp = ktime_get_real(); \
		} \

		bool is_skb_forwardable(const struct net_device dev, const struct sk_buff skb)

net/core/skbuff.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -4851,7 +4851,7 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
		if (hwtstamps)
		skb_hwtstamps(skb) = hwtstamps;
		else
		skb->tstamp = ktime_get_real();
		__net_timestamp(skb);

		__skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
		}