From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5835C433ED for ; Wed, 21 Apr 2021 23:21:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B321961421 for ; Wed, 21 Apr 2021 23:21:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240117AbhDUXWb (ORCPT ); Wed, 21 Apr 2021 19:22:31 -0400 Received: from www62.your-server.de ([213.133.104.62]:47814 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231296AbhDUXWb (ORCPT ); Wed, 21 Apr 2021 19:22:31 -0400 Received: from sslproxy06.your-server.de ([78.46.172.3]) by www62.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1lZMAO-000G2g-Na; Thu, 22 Apr 2021 01:21:56 +0200 Received: from [85.7.101.30] (helo=linux.home) by sslproxy06.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lZMAO-000XQA-EU; Thu, 22 Apr 2021 01:21:56 +0200 Subject: Re: [PATCH bpf-next v3 2/3] libbpf: add low level TC-BPF API To: Kumar Kartikeya Dwivedi Cc: bpf@vger.kernel.org, =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , Alexei Starovoitov , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , netdev@vger.kernel.org References: <20210420193740.124285-1-memxor@gmail.com> <20210420193740.124285-3-memxor@gmail.com> <9b0aab2c-9b92-0bcb-2064-f66dd39e7552@iogearbox.net> <20210421230858.ruwqw5jvsy7cjioy@apollo> From: Daniel Borkmann Message-ID: <21c55619-e26d-d901-076e-20f55302c2fd@iogearbox.net> Date: Thu, 22 Apr 2021 01:21:55 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20210421230858.ruwqw5jvsy7cjioy@apollo> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.4/26147/Wed Apr 21 13:06:05 2021) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 4/22/21 1:08 AM, Kumar Kartikeya Dwivedi wrote: > On Thu, Apr 22, 2021 at 04:29:28AM IST, Daniel Borkmann wrote: >> On 4/20/21 9:37 PM, Kumar Kartikeya Dwivedi wrote: >> [...] >>> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h >>> index bec4e6a6e31d..b4ed6a41ea70 100644 >>> --- a/tools/lib/bpf/libbpf.h >>> +++ b/tools/lib/bpf/libbpf.h >>> @@ -16,6 +16,8 @@ >>> #include >>> #include // for size_t >>> #include >>> +#include >>> +#include >>> #include "libbpf_common.h" >>> @@ -775,6 +777,48 @@ LIBBPF_API int bpf_linker__add_file(struct bpf_linker *linker, const char *filen >>> LIBBPF_API int bpf_linker__finalize(struct bpf_linker *linker); >>> LIBBPF_API void bpf_linker__free(struct bpf_linker *linker); >>> +/* Convenience macros for the clsact attach hooks */ >>> +#define BPF_TC_CLSACT_INGRESS TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_INGRESS) >>> +#define BPF_TC_CLSACT_EGRESS TC_H_MAKE(TC_H_CLSACT, TC_H_MIN_EGRESS) >> >> I would abstract those away into an enum, plus avoid having to pull in >> linux/pkt_sched.h and linux/tc_act/tc_bpf.h from main libbpf.h header. >> >> Just add a enum { BPF_TC_DIR_INGRESS, BPF_TC_DIR_EGRESS, } and then the >> concrete tc bits (TC_H_MAKE()) can be translated internally. > > Ok, will do. > >>> +struct bpf_tc_opts { >>> + size_t sz; >> >> Is this set anywhere? > > This is needed by the OPTS_* infrastructure. > >>> + __u32 handle; >>> + __u32 class_id; >> >> I'd remove class_id from here as well given in direct-action a BPF prog can >> set it if needed. > > Ok, makes sense. > >>> + __u16 priority; >>> + bool replace; >>> + size_t :0; >> >> What's the rationale for this padding? > > dde7b3f5f2f4 ("libbpf: Add explicit padding to bpf_xdp_set_link_opts") Hm, fair enough. >>> +}; >>> + >>> +#define bpf_tc_opts__last_field replace >>> + >>> +/* Acts as a handle for an attached filter */ >>> +struct bpf_tc_attach_id { >> >> nit: maybe bpf_tc_ctx >> > > Noted. > >>> + __u32 handle; >>> + __u16 priority; >>> +}; >>> + >>> +struct bpf_tc_info { >>> + struct bpf_tc_attach_id id; >>> + __u16 protocol; >>> + __u32 chain_index; >>> + __u32 prog_id; >>> + __u8 tag[BPF_TAG_SIZE]; >>> + __u32 class_id; >>> + __u32 bpf_flags; >>> + __u32 bpf_flags_gen; >> >> Given we do not yet have any setters e.g. for offload, etc, the one thing >> I'd see useful and crucial initially is prog_id. >> >> The protocol, chain_index, and I would also include tag should be dropped. > > A future user of this API needs to know the tag, so I would like to keep that. > The rest we can drop, and probably document the default values explicitly. Couldn't this be added along with the future patch for the [future] user? The tag should be the tag of the prog itself, so if you have prog_id, you could also retrieve the same tag from the prog. The tag was basically from the early days where we didn't have bpf_prog_get_info_by_fd(). What does that future user need to do different here? Thanks, Daniel