Commit 4d25ca2d authored by Abhishek Chauhan's avatar Abhishek Chauhan Committed by Martin KaFai Lau
Browse files

net: Rename mono_delivery_time to tstamp_type for scalabilty 



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 on enum defined
in 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 tstamp_type to distinguish between mono and real time.

Also skb_set_delivery_type_by_clockid is a new function which accepts
clockid to determine the tstamp_type.

In future tstamp_type:1 can be extended to support userspace timestamp
by increasing the bitfield.

Signed-off-by: default avatarAbhishek Chauhan <quic_abchauha@quicinc.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Reviewed-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509211834.3235191-2-quic_abchauha@quicinc.com


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent a87f34e7

include/linux/skbuff.h

+39 −13
Original line number Diff line number Diff line
@@ -706,6 +706,11 @@ typedef unsigned int sk_buff_data_t; 
typedef unsigned char *sk_buff_data_t;

#endif



enum skb_tstamp_type {

	SKB_CLOCK_REALTIME,

	SKB_CLOCK_MONOTONIC,

};



/**

 * DOC: Basic sk_buff geometry

 *
@@ -823,10 +828,8 @@ 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

 *		delivery_time in mono clock base (i.e. EDT).  Otherwise, the

 *		skb->tstamp has the (rcv) timestamp at ingress and

 *		delivery_time at egress.

 *	@tstamp_type: When set, skb->tstamp has the

 *		delivery_time clock base of skb->tstamp.

 *	@napi_id: id of the NAPI struct this skb came from

 *	@sender_cpu: (aka @napi_id) source CPU in XPS

 *	@alloc_cpu: CPU which did the skb allocation.
@@ -954,7 +957,7 @@ 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_tstamp_type */

#ifdef CONFIG_NET_XGRESS

	__u8			tc_at_ingress:1;	/* See TC_AT_INGRESS_MASK */

	__u8			tc_skip_classify:1;
@@ -4183,7 +4186,7 @@ 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 = SKB_CLOCK_REALTIME;

}



static inline ktime_t net_timedelta(ktime_t t)
@@ -4192,10 +4195,33 @@ 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;



	if (kt)

		skb->tstamp_type = tstamp_type;

	else

		skb->tstamp_type = SKB_CLOCK_REALTIME;

}



static inline void skb_set_delivery_type_by_clockid(struct sk_buff *skb,

						    ktime_t kt, clockid_t clockid)

{

	u8 tstamp_type = SKB_CLOCK_REALTIME;



	switch (clockid) {

	case CLOCK_REALTIME:

		break;

	case CLOCK_MONOTONIC:

		tstamp_type = SKB_CLOCK_MONOTONIC;

		break;

	default:

		WARN_ON_ONCE(1);

		kt = 0;

	}



	skb_set_delivery_time(skb, kt, tstamp_type);

}



DECLARE_STATIC_KEY_FALSE(netstamp_needed_key);
@@ -4205,8 +4231,8 @@ 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 = SKB_CLOCK_REALTIME;

		if (static_branch_unlikely(&netstamp_needed_key))

			skb->tstamp = ktime_get_real();

		else
@@ -4216,7 +4242,7 @@ 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;
@@ -4224,7 +4250,7 @@ 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)

		return 0;



	return skb->tstamp;
@@ -4232,7 +4258,7 @@ 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 != SKB_CLOCK_MONOTONIC && skb->tstamp)

		return skb->tstamp;



	if (static_branch_unlikely(&netstamp_needed_key) || cond)

include/net/inet_frag.h

+2 −2
Original line number Diff line number Diff line
@@ -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;

net/bridge/netfilter/nf_conntrack_bridge.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -2160,7 +2160,7 @@ 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 = SKB_CLOCK_REALTIME;

	if (static_branch_unlikely(&netstamp_needed_key))

		skb->tstamp = ktime_get_real();

}

net/core/filter.c

+5 −5
Original line number Diff line number Diff line
@@ -7730,13 +7730,13 @@ 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 = SKB_CLOCK_MONOTONIC;

		break;

	case BPF_SKB_TSTAMP_UNSPEC:

		if (tstamp)

			return -EINVAL;

		skb->tstamp = 0;

		skb->mono_delivery_time = 0;

		skb->tstamp_type = SKB_CLOCK_REALTIME;

		break;

	default:

		return -EINVAL;
@@ -9443,7 +9443,7 @@ 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,

		 * read 0 as the (rcv) timestamp.

		 */

		*insn++ = BPF_MOV64_IMM(value_reg, 0);
@@ -9468,7 +9468,7 @@ 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.

	 * skb->tstamp_type bit also.

	 */

	if (!prog->tstamp_type_access) {

		__u8 tmp_reg = BPF_REG_AX;
@@ -9478,7 +9478,7 @@ static struct bpf_insn *bpf_convert_tstamp_write(const struct bpf_prog *prog, 
		*insn++ = BPF_JMP32_IMM(BPF_JSET, tmp_reg, TC_AT_INGRESS_MASK, 1);

		/* goto <store> */

		*insn++ = BPF_JMP_A(2);

		/* <clear>: mono_delivery_time */

		/* <clear>: skb->tstamp_type */

		*insn++ = BPF_ALU32_IMM(BPF_AND, tmp_reg, ~SKB_MONO_DELIVERY_TIME_MASK);

		*insn++ = BPF_STX_MEM(BPF_B, skb_reg, tmp_reg, SKB_BF_MONO_TC_OFFSET);

	}