netdev - Re: [PATCH bpf-next v10 07/12] bpf: add BPF_SOCK_OPS_TS_SW_OPT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b1b7106d-2c36-4663-bf46-807337f792bf@linux.dev>
Date: Wed, 12 Feb 2025 15:18:54 -0800
From: Martin KaFai Lau <martin.lau@...ux.dev>
To: Jason Xing <kerneljasonxing@...il.com>
Cc: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
 pabeni@...hat.com, dsahern@...nel.org, willemdebruijn.kernel@...il.com,
 willemb@...gle.com, ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
 eddyz87@...il.com, song@...nel.org, yonghong.song@...ux.dev,
 john.fastabend@...il.com, kpsingh@...nel.org, sdf@...ichev.me,
 haoluo@...gle.com, jolsa@...nel.org, shuah@...nel.org, ykolal@...com,
 bpf@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH bpf-next v10 07/12] bpf: add BPF_SOCK_OPS_TS_SW_OPT_CB
 callback

On 2/11/25 10:18 PM, Jason Xing wrote:
> Support sw SCM_TSTAMP_SND case for bpf timestamping.
> 
> Add a new sock_ops callback, BPF_SOCK_OPS_TS_SW_OPT_CB. This
> callback will occur at the same timestamping point as the user
> space's software SCM_TSTAMP_SND. The BPF program can use it to
> get the same SCM_TSTAMP_SND timestamp without modifying the
> user-space application.
> 
> Based on this patch, BPF program will get the software
> timestamp when the driver is ready to send the skb. In the
> sebsequent patch, the hardware timestamp will be supported.
> 
> Signed-off-by: Jason Xing <kerneljasonxing@...il.com>
> ---
>   include/linux/skbuff.h         | 2 +-
>   include/uapi/linux/bpf.h       | 4 ++++
>   net/core/skbuff.c              | 9 ++++++++-
>   tools/include/uapi/linux/bpf.h | 4 ++++
>   4 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 52f6e033e704..76582500c5ea 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -4568,7 +4568,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
>   static inline void skb_tx_timestamp(struct sk_buff *skb)
>   {
>   	skb_clone_tx_timestamp(skb);
> -	if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP)
> +	if (skb_shinfo(skb)->tx_flags & (SKBTX_SW_TSTAMP | SKBTX_BPF))
>   		skb_tstamp_tx(skb, NULL);
>   }
>   
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 68664ececdc0..b3bd92281084 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -7039,6 +7039,10 @@ enum {
>   					 * dev layer when SK_BPF_CB_TX_TIMESTAMPING
>   					 * feature is on.
>   					 */
> +	BPF_SOCK_OPS_TS_SW_OPT_CB,	/* Called when skb is about to send
> +					 * to the nic when SK_BPF_CB_TX_TIMESTAMPING
> +					 * feature is on.
> +					 */
>   };
>   
>   /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 7bac5e950e3d..d80d2137692f 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -5557,6 +5557,7 @@ static bool skb_tstamp_tx_report_so_timestamping(struct sk_buff *skb,
>   }
>   
>   static void skb_tstamp_tx_report_bpf_timestamping(struct sk_buff *skb,
> +						  struct skb_shared_hwtstamps *hwts,

s/hwts/hwtstamps/
Use the same argument name as all other functions in this file. Its caller is 
using hwtstamps as the argument name also. Easier to follow.

Probably the same for the skb_tstamp_tx_report_so_timestamping().

>   						  struct sock *sk,
>   						  int tstype)
>   {
> @@ -5566,6 +5567,11 @@ static void skb_tstamp_tx_report_bpf_timestamping(struct sk_buff *skb,
>   	case SCM_TSTAMP_SCHED:
>   		op = BPF_SOCK_OPS_TS_SCHED_OPT_CB;
>   		break;
> +	case SCM_TSTAMP_SND:
> +		if (hwts)
> +			return;
> +		op = BPF_SOCK_OPS_TS_SW_OPT_CB;
> +		break;
>   	default:
>   		return;
>   	}
> @@ -5586,7 +5592,8 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
>   		return;
>   
>   	if (skb_shinfo(orig_skb)->tx_flags & SKBTX_BPF)
> -		skb_tstamp_tx_report_bpf_timestamping(orig_skb, sk, tstype);
> +		skb_tstamp_tx_report_bpf_timestamping(orig_skb, hwtstamps,
> +						      sk, tstype);
>   
>   	if (!skb_tstamp_tx_report_so_timestamping(orig_skb, hwtstamps, tstype))
>   		return;
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index eed91b7296b7..9bd1c7c77b17 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -7029,6 +7029,10 @@ enum {
>   					 * dev layer when SK_BPF_CB_TX_TIMESTAMPING
>   					 * feature is on.
>   					 */
> +	BPF_SOCK_OPS_TS_SW_OPT_CB,	/* Called when skb is about to send
> +					 * to the nic when SK_BPF_CB_TX_TIMESTAMPING
> +					 * feature is on.
> +					 */
>   };
>   
>   /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect