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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 B422BC433E0 for ; Fri, 10 Jul 2020 08:37:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9383F2078D for ; Fri, 10 Jul 2020 08:37:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="c3x2FiQT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726816AbgGJIhJ (ORCPT ); Fri, 10 Jul 2020 04:37:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726644AbgGJIhI (ORCPT ); Fri, 10 Jul 2020 04:37:08 -0400 Received: from mail-lj1-x242.google.com (mail-lj1-x242.google.com [IPv6:2a00:1450:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7038AC08C5CE for ; Fri, 10 Jul 2020 01:37:08 -0700 (PDT) Received: by mail-lj1-x242.google.com with SMTP id d17so5525764ljl.3 for ; Fri, 10 Jul 2020 01:37:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version; bh=fejdS5oXDBhA7SCXC2ps+GSa09Mm4PzKTz47mMKeznA=; b=c3x2FiQT6TXoFMi/lEyaa5Bcxv2wDEzGBOkaSSkCiIp5nsVGuNPzUTudrN7fLc1cMo WNHvoLDD8rVMEStHW0YH5o6c2RpKi07IJPBFRptIYSQ0yGqfoOz7QqoLjW+fNThOnmv2 XHkH7cmyfWtQKQnlTZ6SaWN8R0i0IapKfj540= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version; bh=fejdS5oXDBhA7SCXC2ps+GSa09Mm4PzKTz47mMKeznA=; b=HCgXucIuTAolP37hAiXOC+rIdgFSHQUGOMHvZxKZN2bQRltyckDvZ91/lGV6kNduQM qx40LQikRyOFIGcci0O1u6L4SxgLZo9FTBwYbTSKF1rXh1k+1dU+9ifrQOrz34qV4xoN 2t1x4I2ExssMVHn8e1JcO2lvx8QTOgMgimfKxoqIH0pMhxS2/EdBgaDmjKyq+ibNmieQ idW2AQKLmkPJxnXcdDJYygTtaLCjAFic1xv9JIIfTL2/Lrvm5hb7x4TxtBBqnd+65nUW cpe6Q0RpqEW/OGQh1LgXw8YJ7IzXKNIwvR1CZ4tR4sKGmJ3WKBa8Zr7EzG5UnB99l46H Y7BQ== X-Gm-Message-State: AOAM530IOW6wus1fav0AUXm6IKeUwGuNJR8TRClHHzAxmDSbmKwn+QN0 QDAj470vXlvdAqNW2YCC+Cc/Tg== X-Google-Smtp-Source: ABdhPJyDO+qq/oCenn+hN8r63rNpM0pYXwg+q/LIjKEgOWJ8pfCfGAw0CTosqI9qnesX4M/iqbRfTg== X-Received: by 2002:a2e:9a47:: with SMTP id k7mr27428157ljj.96.1594370226759; Fri, 10 Jul 2020 01:37:06 -0700 (PDT) Received: from cloudflare.com ([2a02:a310:c262:aa00:b35e:8938:2c2a:ba8b]) by smtp.gmail.com with ESMTPSA id v19sm1897418lfi.65.2020.07.10.01.37.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jul 2020 01:37:06 -0700 (PDT) References: <20200702092416.11961-1-jakub@cloudflare.com> <20200702092416.11961-13-jakub@cloudflare.com> <87h7ugadpt.fsf@cloudflare.com> User-agent: mu4e 1.1.0; emacs 26.3 From: Jakub Sitnicki To: Andrii Nakryiko Cc: bpf , Networking , kernel-team , Alexei Starovoitov , Daniel Borkmann , "David S. Miller" , Jakub Kicinski Subject: Re: [PATCH bpf-next v3 12/16] libbpf: Add support for SK_LOOKUP program type In-reply-to: Date: Fri, 10 Jul 2020 10:37:04 +0200 Message-ID: <87d053ahqn.fsf@cloudflare.com> MIME-Version: 1.0 Content-Type: text/plain Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Jul 10, 2020 at 01:13 AM CEST, Andrii Nakryiko wrote: > On Thu, Jul 9, 2020 at 8:51 AM Jakub Sitnicki wrote: >> >> On Thu, Jul 09, 2020 at 06:23 AM CEST, Andrii Nakryiko wrote: >> > On Thu, Jul 2, 2020 at 2:25 AM Jakub Sitnicki wrote: >> >> >> >> Make libbpf aware of the newly added program type, and assign it a >> >> section name. >> >> >> >> Signed-off-by: Jakub Sitnicki >> >> --- >> >> >> >> Notes: >> >> v3: >> >> - Move new libbpf symbols to version 0.1.0. >> >> - Set expected_attach_type in probe_load for new prog type. >> >> >> >> v2: >> >> - Add new libbpf symbols to version 0.0.9. (Andrii) >> >> >> >> tools/lib/bpf/libbpf.c | 3 +++ >> >> tools/lib/bpf/libbpf.h | 2 ++ >> >> tools/lib/bpf/libbpf.map | 2 ++ >> >> tools/lib/bpf/libbpf_probes.c | 3 +++ >> >> 4 files changed, 10 insertions(+) >> >> >> >> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c >> >> index 4ea7f4f1a691..ddcbb5dd78df 100644 >> >> --- a/tools/lib/bpf/libbpf.c >> >> +++ b/tools/lib/bpf/libbpf.c >> >> @@ -6793,6 +6793,7 @@ BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT); >> >> BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING); >> >> BPF_PROG_TYPE_FNS(struct_ops, BPF_PROG_TYPE_STRUCT_OPS); >> >> BPF_PROG_TYPE_FNS(extension, BPF_PROG_TYPE_EXT); >> >> +BPF_PROG_TYPE_FNS(sk_lookup, BPF_PROG_TYPE_SK_LOOKUP); >> >> >> >> enum bpf_attach_type >> >> bpf_program__get_expected_attach_type(struct bpf_program *prog) >> >> @@ -6969,6 +6970,8 @@ static const struct bpf_sec_def section_defs[] = { >> >> BPF_EAPROG_SEC("cgroup/setsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT, >> >> BPF_CGROUP_SETSOCKOPT), >> >> BPF_PROG_SEC("struct_ops", BPF_PROG_TYPE_STRUCT_OPS), >> >> + BPF_EAPROG_SEC("sk_lookup", BPF_PROG_TYPE_SK_LOOKUP, >> >> + BPF_SK_LOOKUP), >> > >> > So it's a BPF_PROG_TYPE_SK_LOOKUP with attach type BPF_SK_LOOKUP. What >> > other potential attach types could there be for >> > BPF_PROG_TYPE_SK_LOOKUP? How the section name will look like in that >> > case? >> >> BPF_PROG_TYPE_SK_LOOKUP won't have any other attach types that I can >> forsee. There is a single attach type shared by tcp4, tcp6, udp4, and >> udp6 hook points. If we hook it up in the future say to sctp, I expect >> the same attach point will be reused. > > So you needed to add to bpf_attach_type just to fit into link_create > model of attach_type -> prog_type, right? As I mentioned extending > bpf_attach_type has a real cost on each cgroup, so we either need to > solve that problem (and I think that would be the best) or we can > change link_create logic to not require attach_type for programs like > SK_LOOKUP, where it's clear without attach type. Right. I was thinking about that a bit. For prog types map 1:1 to an attach type, like flow_dissector or proposed sk_lookup, we don't really to know the attach type to attach the program. PROG_QUERY is more problematic though. But I imagine we could introduce a flag like BPF_QUERY_F_BY_PROG_TYPE that would make the kernel interpret attr->query.attach_type as prog type. PROG_DETACH is yet another story but sk_lookup uses only link-based attachment, so I'm ignoring it here. What also might get in the way is the fact that there is no bpf_attach_type value reserved for unspecified attach type at the moment. We would have to ensure that the first enum, BPF_CGROUP_INET_INGRESS, is not treated as an exact attach type. > > Second order question was if we have another attach type, having > SEC("sk_lookup/just_kidding_something_else") would be a bit weird :) > But it seems like that's not a concern. Yes. Sorry, I didn't mean to leave it unanswered. Just assumed that it was obvious that it's not the case. I've been happily using the part of section name following "sk_lookup" prefix to name the programs just to make section names in ELF object unique: SEC("sk_lookup/lookup_pass") SEC("sk_lookup/lookup_drop") SEC("sk_lookup/redir_port")