On 4/15/2024 1:46 PM, Willem de Bruijn wrote: > Abhishek Chauhan (ABC) wrote: >> >> >> On 4/13/2024 11:54 AM, Willem de Bruijn wrote: >>> 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@xxxxxxxxx/ >>>> Signed-off-by: Abhishek Chauhan <quic_abchauha@xxxxxxxxxxx> >>>> --- >>>> 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(-) >>>> >>>> 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 */ >>>> +}; >>> >>> Minor: inconsistent capitalization >>> >> I will fix this. >> >>>> + >>>> /** >>>> * 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 */ >>> >>> Also remove reference to MONO_DELIVERY_TIME_MASK, or instead refer to >>> skb_tstamp_type. >>> >>>> #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; >>>> + } >>> >>> Technically this leaves the tstamp_type undefined if (skb, 0, CLOCK_REAL) >> Do you think i should be checking for valid value of tstamp before setting the tstamp_type ? Only then set it. > > A kt of 0 is interpreted as resetting the type. That should probably > be maintained. > > For SO_TIMESTAMPING, a mono delivery time of 0 does have some meaning. > In __sock_recv_timestamp: > > /* Race occurred between timestamp enabling and packet > receiving. Fill in the current time for now. */ > if (need_software_tstamp && skb->tstamp == 0) { > __net_timestamp(skb); > false_tstamp = 1; > } Well in that case the above logic still resets the tstamp and sets the tstamp_type to CLOCK_REAL(value 0). Anyway the tstamp_type will be 0 to begin with. The logic is still inline with previous implementation, because previously if kt was 0 then kt && mono sets the tstamp_type (previously called as mono_delivery_time) to 0 (i.e SKB_CLOCK_REAL).
