netdev - Re: [PATCH bpf-next v8 10/12] bpf: make TCP tx timestamp bpf extension work

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: <20250204175744.3f92c33e@kernel.org>
Date: Tue, 4 Feb 2025 17:57:44 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Jason Xing <kerneljasonxing@...il.com>
Cc: davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com,
 dsahern@...nel.org, willemdebruijn.kernel@...il.com, willemb@...gle.com,
 ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
 martin.lau@...ux.dev, 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, horms@...nel.org,
 bpf@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH bpf-next v8 10/12] bpf: make TCP tx timestamp bpf
 extension work

On Wed,  5 Feb 2025 02:30:22 +0800 Jason Xing wrote:
> +	if (cgroup_bpf_enabled(CGROUP_SOCK_OPS) &&
> +	    SK_BPF_CB_FLAG_TEST(sk, SK_BPF_CB_TX_TIMESTAMPING) && skb) {
> +		struct skb_shared_info *shinfo = skb_shinfo(skb);
> +		struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
> +
> +		tcb->txstamp_ack_bpf = 1;
> +		shinfo->tx_flags |= SKBTX_BPF;
> +		shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
> +	}

If BPF program is attached we'll timestamp all skbs? Am I reading this
right?

Wouldn't it be better to let BPF_SOCK_OPS_TS_SND_CB return whether it's
interested in tracing current packet all the way thru the stack?