From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-175.mta0.migadu.com (out-175.mta0.migadu.com [91.218.175.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8157F1EDA27 for ; Tue, 11 Feb 2025 07:41:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739259721; cv=none; b=HQVZZprpdqy0kSYTCtUyzameCYH86FPFO7elSXcAlIkInUW8UJQzW2a9sFbfkPXQRbK9wI/wP1lu/i/BkLqiHH8tB1AXJnhvqXz5vX5zhVzHJHjnSxhWGkWt+s9fsplcZ9zESMJrTvOpzQ51vYvET+OPu04YTbVcafRF2YXh4OA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739259721; c=relaxed/simple; bh=wqPEFEJXhPEgjqvvQPs60/jcXvpEwF4YVlTJ2HH8uGc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Yot5cqcuqHyMBuMFQI/QAkSiEEJc7PzJAZ0IgERG09Azy6HCjB49PPQwtdX/NfCZSmoIGllP6Ie7GTcXZd6Lx5xPT9Ra8tVeQn7Be0+tzz2t1yqyW5Bqg9yZ3iRPuuI3+hMbozXfNzDSkF8jq/SV51tiVSdq9XQNJMIPl+G0E2Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=aa+HQy3O; arc=none smtp.client-ip=91.218.175.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="aa+HQy3O" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1739259716; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IK3saGkhNUN12X4MEcIQMxeGOn/ySxBzESpOffbZkYk=; b=aa+HQy3OJeJqCqRsPbZP0SYjMFY+g9LHtxvV6MKruPh3Iz0kKvu5GfIizpKUJCEdaF0YyZ F0NSVxv5wkTjVTUhA7vyYpomOLRMNEmi8CotroixHi1ksHiEbQQbypMSsLhlJqISyXh4/A 2oFRHe3vFaCmr6TsMnZc/+Gc5Y8F+S8= Date: Mon, 10 Feb 2025 23:41:49 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v9 11/12] bpf: support selective sampling for bpf timestamping To: Jason Xing Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, willemdebruijn.kernel@gmail.com, willemb@google.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, horms@kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org References: <20250208103220.72294-1-kerneljasonxing@gmail.com> <20250208103220.72294-12-kerneljasonxing@gmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau Content-Language: en-US In-Reply-To: <20250208103220.72294-12-kerneljasonxing@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2/8/25 2:32 AM, Jason Xing wrote: > Use __bpf_kfunc feature to allow bpf prog dynamically and selectively s/Use/Add/ Remove "dynamically". A kfunc can only be called dynamically at runtime. Like: "Add the bpf_sock_ops_enable_tx_tstamp kfunc to allow BPF programs to selectively enable TX timestamping on a skb during tcp_sendmsg..." > to sample/track the skb. For example, the bpf prog will limit tracking > X numbers of packets and then will stop there instead of tracing > all the sendmsgs of matched flow all along. > > Signed-off-by: Jason Xing > --- > kernel/bpf/btf.c | 1 + > net/core/filter.c | 27 ++++++++++++++++++++++++++- > 2 files changed, 27 insertions(+), 1 deletion(-) > > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index 8396ce1d0fba..a65e2eeffb88 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -8535,6 +8535,7 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) > case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: > case BPF_PROG_TYPE_CGROUP_SOCKOPT: > case BPF_PROG_TYPE_CGROUP_SYSCTL: > + case BPF_PROG_TYPE_SOCK_OPS: > return BTF_KFUNC_HOOK_CGROUP; > case BPF_PROG_TYPE_SCHED_ACT: > return BTF_KFUNC_HOOK_SCHED_ACT; > diff --git a/net/core/filter.c b/net/core/filter.c > index 7f56d0bbeb00..db20a947e757 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -12102,6 +12102,21 @@ __bpf_kfunc int bpf_sk_assign_tcp_reqsk(struct __sk_buff *s, struct sock *sk, > #endif > } > > +__bpf_kfunc int bpf_sock_ops_enable_tx_tstamp(struct bpf_sock_ops_kern *skops) I am ok to always enable txstamp_ack here. Please still add a second "u64 flags" argument such that future disable/enable is still possible. > +{ > + struct sk_buff *skb; > + > + if (skops->op != BPF_SOCK_OPS_TS_SND_CB) > + return -EOPNOTSUPP;> + > + skb = skops->skb; > + TCP_SKB_CB(skb)->txstamp_ack = 2; Willem (thanks!) has already mentioned there is a bug. This also brought up that a test is missing: the bpf timestamping and user space's SO_TIMESTAMPING can work without interfering others. The current test only has SK_BPF_CB_TX_TIMESTAMPING on. A test is needed when both SK_BPF_CB_TX_TIMESTAMPING and the user space's SO_TIMESTAMPING are on. The expectation is both of them will work together. > + skb_shinfo(skb)->tx_flags |= SKBTX_BPF; > + skb_shinfo(skb)->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1; > + > + return 0; > +} > + > __bpf_kfunc_end_defs(); > > int bpf_dynptr_from_skb_rdonly(struct __sk_buff *skb, u64 flags, > @@ -12135,6 +12150,10 @@ BTF_KFUNCS_START(bpf_kfunc_check_set_tcp_reqsk) > BTF_ID_FLAGS(func, bpf_sk_assign_tcp_reqsk, KF_TRUSTED_ARGS) > BTF_KFUNCS_END(bpf_kfunc_check_set_tcp_reqsk) > > +BTF_KFUNCS_START(bpf_kfunc_check_set_sock_ops) > +BTF_ID_FLAGS(func, bpf_sock_ops_enable_tx_tstamp, KF_TRUSTED_ARGS) > +BTF_KFUNCS_END(bpf_kfunc_check_set_sock_ops) > + > static const struct btf_kfunc_id_set bpf_kfunc_set_skb = { > .owner = THIS_MODULE, > .set = &bpf_kfunc_check_set_skb, > @@ -12155,6 +12174,11 @@ static const struct btf_kfunc_id_set bpf_kfunc_set_tcp_reqsk = { > .set = &bpf_kfunc_check_set_tcp_reqsk, > }; > > +static const struct btf_kfunc_id_set bpf_kfunc_set_sock_ops = { > + .owner = THIS_MODULE, > + .set = &bpf_kfunc_check_set_sock_ops, > +}; > + > static int __init bpf_kfunc_init(void) > { > int ret; > @@ -12173,7 +12197,8 @@ static int __init bpf_kfunc_init(void) > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, > &bpf_kfunc_set_sock_addr); > - return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_kfunc_set_tcp_reqsk); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_kfunc_set_tcp_reqsk); > + return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SOCK_OPS, &bpf_kfunc_set_sock_ops); > } > late_initcall(bpf_kfunc_init); >