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Message-ID: <da088092-e4cf-4282-b691-0bbc641e3e02@quicinc.com>
Date: Fri, 12 Apr 2024 17:37:59 -0700
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Subject: Re: [RFC PATCH bpf-next v3 1/2] net: Rename mono_delivery_time to
 tstamp_type for scalabilty
Content-Language: en-US
From: "Abhishek Chauhan (ABC)" <quic_abchauha@quicinc.com>
To: "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet
	<edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni
	<pabeni@redhat.com>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, Andrew Halaney <ahalaney@redhat.com>,
        "Willem
 de Bruijn" <willemdebruijn.kernel@gmail.com>,
        Martin KaFai Lau
	<martin.lau@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        "Daniel
 Borkmann" <daniel@iogearbox.net>, bpf <bpf@vger.kernel.org>
CC: <kernel@quicinc.com>
References: <20240412210125.1780574-1-quic_abchauha@quicinc.com>
 <20240412210125.1780574-2-quic_abchauha@quicinc.com>
In-Reply-To: <20240412210125.1780574-2-quic_abchauha@quicinc.com>
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On 4/12/2024 2:01 PM, Abhishek Chauhan wrote:
> mono_delivery_time was added to check if skb->tstamp has delivery
> time in mono clock base (i.e. EDT) otherwise skb->tstamp has
> timestamp in ingress and delivery_time at egress.
> 
> Renaming the bitfield from mono_delivery_time to tstamp_type is for
> extensibilty for other timestamps such as userspace timestamp
> (i.e. SO_TXTIME) set via sock opts.
> 
> As we are renaming the mono_delivery_time to tstamp_type, it makes
> sense to start assigning tstamp_type based out if enum defined as
> part of this commit
> 
> Earlier we used bool arg flag to check if the tstamp is mono in
> function skb_set_delivery_time, Now the signature of the functions
> accepts enum to distinguish between mono and real time
> 
> Bridge driver today has no support to forward the userspace timestamp
> packets and ends up resetting the timestamp. ETF qdisc checks the
> packet coming from userspace and encounters to be 0 thereby dropping
> time sensitive packets. These changes will allow userspace timestamps
> packets to be forwarded from the bridge to NIC drivers.
> 
> In future tstamp_type:1 can be extended to support userspace timestamp
> by increasing the bitfield.
> 
> Link: https://lore.kernel.org/netdev/bc037db4-58bb-4861-ac31-a361a93841d3@linux.dev/
> Signed-off-by: Abhishek Chauhan <quic_abchauha@quicinc.com>
> ---
> Changes since v2
> - Minor changes to commit subject
> 
> Changes since v1
> - Squashed the two commits into one as mentioned by Willem.
> - Introduced switch in skb_set_delivery_time.
> - Renamed and removed directionality aspects w.r.t tstamp_type 
>   as mentioned by Willem.
> 
>  include/linux/skbuff.h                     | 33 +++++++++++++++-------
>  include/net/inet_frag.h                    |  4 +--
>  net/bridge/netfilter/nf_conntrack_bridge.c |  6 ++--
>  net/core/dev.c                             |  2 +-
>  net/core/filter.c                          |  8 +++---
>  net/ipv4/inet_fragment.c                   |  2 +-
>  net/ipv4/ip_fragment.c                     |  2 +-
>  net/ipv4/ip_output.c                       |  8 +++---
>  net/ipv4/tcp_output.c                      | 14 ++++-----
>  net/ipv6/ip6_output.c                      |  6 ++--
>  net/ipv6/netfilter.c                       |  6 ++--
>  net/ipv6/netfilter/nf_conntrack_reasm.c    |  2 +-
>  net/ipv6/reassembly.c                      |  2 +-
>  net/ipv6/tcp_ipv6.c                        |  2 +-
>  net/sched/act_bpf.c                        |  4 +--
>  net/sched/cls_bpf.c                        |  4 +--
>  16 files changed, 59 insertions(+), 46 deletions(-)
> 
self review :- 
 
One more file needs to be updated here net/ieee802154/6lowpan/reassembly.c  :( 

Unfortunately when i compile kdev with defconfig this file never gets compiled on my internal workspace. 

I will find all other instances and update accordingly. 


> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 7135a3e94afd..a83a2120b57f 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -702,6 +702,11 @@ typedef unsigned int sk_buff_data_t;
>  typedef unsigned char *sk_buff_data_t;
>  #endif
>  
> +enum skb_tstamp_type {
> +	CLOCK_REAL = 0, /* Time base is realtime */
> +	CLOCK_MONO = 1, /* Time base is Monotonic */
> +};
> +
>  /**
>   * DOC: Basic sk_buff geometry
>   *
> @@ -819,7 +824,7 @@ typedef unsigned char *sk_buff_data_t;
>   *	@dst_pending_confirm: need to confirm neighbour
>   *	@decrypted: Decrypted SKB
>   *	@slow_gro: state present at GRO time, slower prepare step required
> - *	@mono_delivery_time: When set, skb->tstamp has the
> + *	@tstamp_type: When set, skb->tstamp has the
>   *		delivery_time in mono clock base (i.e. EDT).  Otherwise, the
>   *		skb->tstamp has the (rcv) timestamp at ingress and
>   *		delivery_time at egress.
> @@ -950,7 +955,7 @@ struct sk_buff {
>  	/* private: */
>  	__u8			__mono_tc_offset[0];
>  	/* public: */
> -	__u8			mono_delivery_time:1;	/* See SKB_MONO_DELIVERY_TIME_MASK */
> +	__u8			tstamp_type:1;	/* See SKB_MONO_DELIVERY_TIME_MASK */
>  #ifdef CONFIG_NET_XGRESS
>  	__u8			tc_at_ingress:1;	/* See TC_AT_INGRESS_MASK */
>  	__u8			tc_skip_classify:1;
> @@ -4237,7 +4242,7 @@ 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;
> +	skb->tstamp_type = CLOCK_REAL;
>  }
>  
>  static inline ktime_t net_timedelta(ktime_t t)
> @@ -4246,10 +4251,18 @@ static inline ktime_t net_timedelta(ktime_t t)
>  }
>  
>  static inline void skb_set_delivery_time(struct sk_buff *skb, ktime_t kt,
> -					 bool mono)
> +					  u8 tstamp_type)
>  {
>  	skb->tstamp = kt;
> -	skb->mono_delivery_time = kt && mono;
> +
> +	switch (tstamp_type) {
> +	case CLOCK_REAL:
> +		skb->tstamp_type = CLOCK_REAL;
> +		break;
> +	case CLOCK_MONO:
> +		skb->tstamp_type = kt && tstamp_type;
> +		break;
> +	}
>  }
>  
>  DECLARE_STATIC_KEY_FALSE(netstamp_needed_key);
> @@ -4259,8 +4272,8 @@ DECLARE_STATIC_KEY_FALSE(netstamp_needed_key);
>   */
>  static inline void skb_clear_delivery_time(struct sk_buff *skb)
>  {
> -	if (skb->mono_delivery_time) {
> -		skb->mono_delivery_time = 0;
> +	if (skb->tstamp_type) {
> +		skb->tstamp_type = CLOCK_REAL;
>  		if (static_branch_unlikely(&netstamp_needed_key))
>  			skb->tstamp = ktime_get_real();
>  		else
> @@ -4270,7 +4283,7 @@ static inline void skb_clear_delivery_time(struct sk_buff *skb)
>  
>  static inline void skb_clear_tstamp(struct sk_buff *skb)
>  {
> -	if (skb->mono_delivery_time)
> +	if (skb->tstamp_type)
>  		return;
>  
>  	skb->tstamp = 0;
> @@ -4278,7 +4291,7 @@ static inline void skb_clear_tstamp(struct sk_buff *skb)
>  
>  static inline ktime_t skb_tstamp(const struct sk_buff *skb)
>  {
> -	if (skb->mono_delivery_time)
> +	if (skb->tstamp_type == CLOCK_MONO)
>  		return 0;
>  
>  	return skb->tstamp;
> @@ -4286,7 +4299,7 @@ static inline ktime_t skb_tstamp(const struct sk_buff *skb)
>  
>  static inline ktime_t skb_tstamp_cond(const struct sk_buff *skb, bool cond)
>  {
> -	if (!skb->mono_delivery_time && skb->tstamp)
> +	if (skb->tstamp_type != CLOCK_MONO && skb->tstamp)
>  		return skb->tstamp;
>  
>  	if (static_branch_unlikely(&netstamp_needed_key) || cond)
> diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
> index 153960663ce4..5af6eb14c5db 100644
> --- a/include/net/inet_frag.h
> +++ b/include/net/inet_frag.h
> @@ -76,7 +76,7 @@ struct frag_v6_compare_key {
>   * @stamp: timestamp of the last received fragment
>   * @len: total length of the original datagram
>   * @meat: length of received fragments so far
> - * @mono_delivery_time: stamp has a mono delivery time (EDT)
> + * @tstamp_type: stamp has a mono delivery time (EDT)
>   * @flags: fragment queue flags
>   * @max_size: maximum received fragment size
>   * @fqdir: pointer to struct fqdir
> @@ -97,7 +97,7 @@ struct inet_frag_queue {
>  	ktime_t			stamp;
>  	int			len;
>  	int			meat;
> -	u8			mono_delivery_time;
> +	u8			tstamp_type;
>  	__u8			flags;
>  	u16			max_size;
>  	struct fqdir		*fqdir;
> diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c
> index c3c51b9a6826..816bb0fde718 100644
> --- a/net/bridge/netfilter/nf_conntrack_bridge.c
> +++ b/net/bridge/netfilter/nf_conntrack_bridge.c
> @@ -32,7 +32,7 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk,
>  					   struct sk_buff *))
>  {
>  	int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
> -	bool mono_delivery_time = skb->mono_delivery_time;
> +	u8 tstamp_type = skb->tstamp_type;
>  	unsigned int hlen, ll_rs, mtu;
>  	ktime_t tstamp = skb->tstamp;
>  	struct ip_frag_state state;
> @@ -82,7 +82,7 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk,
>  			if (iter.frag)
>  				ip_fraglist_prepare(skb, &iter);
>  
> -			skb_set_delivery_time(skb, tstamp, mono_delivery_time);
> +			skb_set_delivery_time(skb, tstamp, tstamp_type);
>  			err = output(net, sk, data, skb);
>  			if (err || !iter.frag)
>  				break;
> @@ -113,7 +113,7 @@ static int nf_br_ip_fragment(struct net *net, struct sock *sk,
>  			goto blackhole;
>  		}
>  
> -		skb_set_delivery_time(skb2, tstamp, mono_delivery_time);
> +		skb_set_delivery_time(skb2, tstamp, tstamp_type);
>  		err = output(net, sk, data, skb2);
>  		if (err)
>  			goto blackhole;
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 854a3a28a8d8..77a43c05dfe3 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2146,7 +2146,7 @@ EXPORT_SYMBOL(net_disable_timestamp);
>  static inline void net_timestamp_set(struct sk_buff *skb)
>  {
>  	skb->tstamp = 0;
> -	skb->mono_delivery_time = 0;
> +	skb->tstamp_type = CLOCK_REAL;
>  	if (static_branch_unlikely(&netstamp_needed_key))
>  		skb->tstamp = ktime_get_real();
>  }
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 8d185d99a643..8bb45423df52 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -7709,13 +7709,13 @@ BPF_CALL_3(bpf_skb_set_tstamp, struct sk_buff *, skb,
>  		if (!tstamp)
>  			return -EINVAL;
>  		skb->tstamp = tstamp;
> -		skb->mono_delivery_time = 1;
> +		skb->tstamp_type = CLOCK_MONO;
>  		break;
>  	case BPF_SKB_TSTAMP_UNSPEC:
>  		if (tstamp)
>  			return -EINVAL;
>  		skb->tstamp = 0;
> -		skb->mono_delivery_time = 0;
> +		skb->tstamp_type = CLOCK_REAL;
>  		break;
>  	default:
>  		return -EINVAL;
> @@ -9422,7 +9422,7 @@ static struct bpf_insn *bpf_convert_tstamp_read(const struct bpf_prog *prog,
>  					TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK);
>  		*insn++ = BPF_JMP32_IMM(BPF_JNE, tmp_reg,
>  					TC_AT_INGRESS_MASK | SKB_MONO_DELIVERY_TIME_MASK, 2);
> -		/* skb->tc_at_ingress && skb->mono_delivery_time,
> +		/* skb->tc_at_ingress && skb->tstamp_type:1,
>  		 * read 0 as the (rcv) timestamp.
>  		 */
>  		*insn++ = BPF_MOV64_IMM(value_reg, 0);
> @@ -9447,7 +9447,7 @@ static struct bpf_insn *bpf_convert_tstamp_write(const struct bpf_prog *prog,
>  	 * the bpf prog is aware the tstamp could have delivery time.
>  	 * Thus, write skb->tstamp as is if tstamp_type_access is true.
>  	 * Otherwise, writing at ingress will have to clear the
> -	 * mono_delivery_time bit also.
> +	 * mono_delivery_time (skb->tstamp_type:1)bit also.
>  	 */
>  	if (!prog->tstamp_type_access) {
>  		__u8 tmp_reg = BPF_REG_AX;
> diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c
> index faaec92a46ac..d179a2c84222 100644
> --- a/net/ipv4/inet_fragment.c
> +++ b/net/ipv4/inet_fragment.c
> @@ -619,7 +619,7 @@ void inet_frag_reasm_finish(struct inet_frag_queue *q, struct sk_buff *head,
>  	skb_mark_not_on_list(head);
>  	head->prev = NULL;
>  	head->tstamp = q->stamp;
> -	head->mono_delivery_time = q->mono_delivery_time;
> +	head->tstamp_type = q->tstamp_type;
>  
>  	if (sk)
>  		refcount_add(sum_truesize - head_truesize, &sk->sk_wmem_alloc);
> diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
> index fb947d1613fe..787aa86800f5 100644
> --- a/net/ipv4/ip_fragment.c
> +++ b/net/ipv4/ip_fragment.c
> @@ -355,7 +355,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
>  		qp->iif = dev->ifindex;
>  
>  	qp->q.stamp = skb->tstamp;
> -	qp->q.mono_delivery_time = skb->mono_delivery_time;
> +	qp->q.tstamp_type = skb->tstamp_type;
>  	qp->q.meat += skb->len;
>  	qp->ecn |= ecn;
>  	add_frag_mem_limit(qp->q.fqdir, skb->truesize);
> diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
> index 1fe794967211..62e457f7c02c 100644
> --- a/net/ipv4/ip_output.c
> +++ b/net/ipv4/ip_output.c
> @@ -764,7 +764,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  {
>  	struct iphdr *iph;
>  	struct sk_buff *skb2;
> -	bool mono_delivery_time = skb->mono_delivery_time;
> +	u8 tstamp_type = skb->tstamp_type;
>  	struct rtable *rt = skb_rtable(skb);
>  	unsigned int mtu, hlen, ll_rs;
>  	struct ip_fraglist_iter iter;
> @@ -856,7 +856,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  				}
>  			}
>  
> -			skb_set_delivery_time(skb, tstamp, mono_delivery_time);
> +			skb_set_delivery_time(skb, tstamp, tstamp_type);
>  			err = output(net, sk, skb);
>  
>  			if (!err)
> @@ -912,7 +912,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  		/*
>  		 *	Put this fragment into the sending queue.
>  		 */
> -		skb_set_delivery_time(skb2, tstamp, mono_delivery_time);
> +		skb_set_delivery_time(skb2, tstamp, tstamp_type);
>  		err = output(net, sk, skb2);
>  		if (err)
>  			goto fail;
> @@ -1649,7 +1649,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
>  			  arg->csumoffset) = csum_fold(csum_add(nskb->csum,
>  								arg->csum));
>  		nskb->ip_summed = CHECKSUM_NONE;
> -		nskb->mono_delivery_time = !!transmit_time;
> +		nskb->tstamp_type = !!transmit_time;
>  		if (txhash)
>  			skb_set_hash(nskb, txhash, PKT_HASH_TYPE_L4);
>  		ip_push_pending_frames(sk, &fl4);
> diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
> index 9282fafc0e61..42e6ed1decf4 100644
> --- a/net/ipv4/tcp_output.c
> +++ b/net/ipv4/tcp_output.c
> @@ -1299,7 +1299,7 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
>  	tp = tcp_sk(sk);
>  	prior_wstamp = tp->tcp_wstamp_ns;
>  	tp->tcp_wstamp_ns = max(tp->tcp_wstamp_ns, tp->tcp_clock_cache);
> -	skb_set_delivery_time(skb, tp->tcp_wstamp_ns, true);
> +	skb_set_delivery_time(skb, tp->tcp_wstamp_ns, CLOCK_MONO);
>  	if (clone_it) {
>  		oskb = skb;
>  
> @@ -1649,7 +1649,7 @@ int tcp_fragment(struct sock *sk, enum tcp_queue tcp_queue,
>  
>  	skb_split(skb, buff, len);
>  
> -	skb_set_delivery_time(buff, skb->tstamp, true);
> +	skb_set_delivery_time(buff, skb->tstamp, CLOCK_MONO);
>  	tcp_fragment_tstamp(skb, buff);
>  
>  	old_factor = tcp_skb_pcount(skb);
> @@ -2730,7 +2730,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
>  		if (unlikely(tp->repair) && tp->repair_queue == TCP_SEND_QUEUE) {
>  			/* "skb_mstamp_ns" is used as a start point for the retransmit timer */
>  			tp->tcp_wstamp_ns = tp->tcp_clock_cache;
> -			skb_set_delivery_time(skb, tp->tcp_wstamp_ns, true);
> +			skb_set_delivery_time(skb, tp->tcp_wstamp_ns, CLOCK_MONO);
>  			list_move_tail(&skb->tcp_tsorted_anchor, &tp->tsorted_sent_queue);
>  			tcp_init_tso_segs(skb, mss_now);
>  			goto repair; /* Skip network transmission */
> @@ -3713,11 +3713,11 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
>  #ifdef CONFIG_SYN_COOKIES
>  	if (unlikely(synack_type == TCP_SYNACK_COOKIE && ireq->tstamp_ok))
>  		skb_set_delivery_time(skb, cookie_init_timestamp(req, now),
> -				      true);
> +				      CLOCK_MONO);
>  	else
>  #endif
>  	{
> -		skb_set_delivery_time(skb, now, true);
> +		skb_set_delivery_time(skb, now, CLOCK_MONO);
>  		if (!tcp_rsk(req)->snt_synack) /* Timestamp first SYNACK */
>  			tcp_rsk(req)->snt_synack = tcp_skb_timestamp_us(skb);
>  	}
> @@ -3804,7 +3804,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
>  	bpf_skops_write_hdr_opt((struct sock *)sk, skb, req, syn_skb,
>  				synack_type, &opts);
>  
> -	skb_set_delivery_time(skb, now, true);
> +	skb_set_delivery_time(skb, now, CLOCK_MONO);
>  	tcp_add_tx_delay(skb, tp);
>  
>  	return skb;
> @@ -3988,7 +3988,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
>  
>  	err = tcp_transmit_skb(sk, syn_data, 1, sk->sk_allocation);
>  
> -	skb_set_delivery_time(syn, syn_data->skb_mstamp_ns, true);
> +	skb_set_delivery_time(syn, syn_data->skb_mstamp_ns, CLOCK_MONO);
>  
>  	/* Now full SYN+DATA was cloned and sent (or not),
>  	 * remove the SYN from the original skb (syn_data)
> diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
> index b9dd3a66e423..a9e819115622 100644
> --- a/net/ipv6/ip6_output.c
> +++ b/net/ipv6/ip6_output.c
> @@ -859,7 +859,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
>  	struct ipv6_pinfo *np = skb->sk && !dev_recursion_level() ?
>  				inet6_sk(skb->sk) : NULL;
> -	bool mono_delivery_time = skb->mono_delivery_time;
> +	u8 tstamp_type = skb->tstamp_type;
>  	struct ip6_frag_state state;
>  	unsigned int mtu, hlen, nexthdr_offset;
>  	ktime_t tstamp = skb->tstamp;
> @@ -955,7 +955,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  			if (iter.frag)
>  				ip6_fraglist_prepare(skb, &iter);
>  
> -			skb_set_delivery_time(skb, tstamp, mono_delivery_time);
> +			skb_set_delivery_time(skb, tstamp, tstamp_type);
>  			err = output(net, sk, skb);
>  			if (!err)
>  				IP6_INC_STATS(net, ip6_dst_idev(&rt->dst),
> @@ -1016,7 +1016,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  		/*
>  		 *	Put this fragment into the sending queue.
>  		 */
> -		skb_set_delivery_time(frag, tstamp, mono_delivery_time);
> +		skb_set_delivery_time(frag, tstamp, tstamp_type);
>  		err = output(net, sk, frag);
>  		if (err)
>  			goto fail;
> diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c
> index 53d255838e6a..e0c2347b4dc6 100644
> --- a/net/ipv6/netfilter.c
> +++ b/net/ipv6/netfilter.c
> @@ -126,7 +126,7 @@ int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  				  struct sk_buff *))
>  {
>  	int frag_max_size = BR_INPUT_SKB_CB(skb)->frag_max_size;
> -	bool mono_delivery_time = skb->mono_delivery_time;
> +	u8 tstamp_type = skb->tstamp_type;
>  	ktime_t tstamp = skb->tstamp;
>  	struct ip6_frag_state state;
>  	u8 *prevhdr, nexthdr = 0;
> @@ -192,7 +192,7 @@ int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  			if (iter.frag)
>  				ip6_fraglist_prepare(skb, &iter);
>  
> -			skb_set_delivery_time(skb, tstamp, mono_delivery_time);
> +			skb_set_delivery_time(skb, tstamp, tstamp_type);
>  			err = output(net, sk, data, skb);
>  			if (err || !iter.frag)
>  				break;
> @@ -225,7 +225,7 @@ int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  			goto blackhole;
>  		}
>  
> -		skb_set_delivery_time(skb2, tstamp, mono_delivery_time);
> +		skb_set_delivery_time(skb2, tstamp, tstamp_type);
>  		err = output(net, sk, data, skb2);
>  		if (err)
>  			goto blackhole;
> diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
> index d0dcbaca1994..5cc5d823d33f 100644
> --- a/net/ipv6/netfilter/nf_conntrack_reasm.c
> +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
> @@ -264,7 +264,7 @@ static int nf_ct_frag6_queue(struct frag_queue *fq, struct sk_buff *skb,
>  		fq->iif = dev->ifindex;
>  
>  	fq->q.stamp = skb->tstamp;
> -	fq->q.mono_delivery_time = skb->mono_delivery_time;
> +	fq->q.tstamp_type = skb->tstamp_type;
>  	fq->q.meat += skb->len;
>  	fq->ecn |= ecn;
>  	if (payload_len > fq->q.max_size)
> diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
> index acb4f119e11f..ea724ff558b4 100644
> --- a/net/ipv6/reassembly.c
> +++ b/net/ipv6/reassembly.c
> @@ -198,7 +198,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
>  		fq->iif = dev->ifindex;
>  
>  	fq->q.stamp = skb->tstamp;
> -	fq->q.mono_delivery_time = skb->mono_delivery_time;
> +	fq->q.tstamp_type = skb->tstamp_type;
>  	fq->q.meat += skb->len;
>  	fq->ecn |= ecn;
>  	add_frag_mem_limit(fq->q.fqdir, skb->truesize);
> diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
> index 3aa9da5c9a66..b60196061489 100644
> --- a/net/ipv6/tcp_ipv6.c
> +++ b/net/ipv6/tcp_ipv6.c
> @@ -975,7 +975,7 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
>  			mark = inet_twsk(sk)->tw_mark;
>  		else
>  			mark = READ_ONCE(sk->sk_mark);
> -		skb_set_delivery_time(buff, tcp_transmit_time(sk), true);
> +		skb_set_delivery_time(buff, tcp_transmit_time(sk), CLOCK_MONO);
>  	}
>  	if (txhash) {
>  		/* autoflowlabel/skb_get_hash_flowi6 rely on buff->hash */
> diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
> index 0e3cf11ae5fc..1f8b5a3f065e 100644
> --- a/net/sched/act_bpf.c
> +++ b/net/sched/act_bpf.c
> @@ -54,8 +54,8 @@ TC_INDIRECT_SCOPE int tcf_bpf_act(struct sk_buff *skb,
>  		bpf_compute_data_pointers(skb);
>  		filter_res = bpf_prog_run(filter, skb);
>  	}
> -	if (unlikely(!skb->tstamp && skb->mono_delivery_time))
> -		skb->mono_delivery_time = 0;
> +	if (unlikely(!skb->tstamp && skb->tstamp_type))
> +		skb->tstamp_type = CLOCK_REAL;
>  	if (skb_sk_is_prefetched(skb) && filter_res != TC_ACT_OK)
>  		skb_orphan(skb);
>  
> diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
> index 5e83e890f6a4..3f843e0eea3c 100644
> --- a/net/sched/cls_bpf.c
> +++ b/net/sched/cls_bpf.c
> @@ -104,8 +104,8 @@ TC_INDIRECT_SCOPE int cls_bpf_classify(struct sk_buff *skb,
>  			bpf_compute_data_pointers(skb);
>  			filter_res = bpf_prog_run(prog->filter, skb);
>  		}
> -		if (unlikely(!skb->tstamp && skb->mono_delivery_time))
> -			skb->mono_delivery_time = 0;
> +		if (unlikely(!skb->tstamp && skb->tstamp_type))
> +			skb->tstamp_type = CLOCK_REAL;
>  
>  		if (prog->exts_integrated) {
>  			res->class   = 0;