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=-13.1 required=3.0 tests=BAYES_00,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, USER_AGENT_GIT autolearn=unavailable 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 A4A7AC433E3 for ; Fri, 17 Jul 2020 10:35:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A5402080D for ; Fri, 17 Jul 2020 10:35:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="nEcDn0Df" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726205AbgGQKfn (ORCPT ); Fri, 17 Jul 2020 06:35:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726013AbgGQKfm (ORCPT ); Fri, 17 Jul 2020 06:35:42 -0400 Received: from mail-lf1-x141.google.com (mail-lf1-x141.google.com [IPv6:2a00:1450:4864:20::141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BA0F1C061755 for ; Fri, 17 Jul 2020 03:35:41 -0700 (PDT) Received: by mail-lf1-x141.google.com with SMTP id t9so5746737lfl.5 for ; Fri, 17 Jul 2020 03:35:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Ky7Uwd6iOLNxL3k0LttI/qHMrfh4/rNGFNpqXTzD72k=; b=nEcDn0DfA+WcArBQl/5WVvOkpMc5OjsLMqzCglcytwykLk0dvf1TJLylKhKjn6889z OGPV3utedExOtYpkksOuyx/BmTkzMsoCbiF9Ul/quwune76CLLTwvzxM4tvQYQbAPvFD TOWiiwXWvCdpboUe3d3qD5mcjrpiaR/9xi1po= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Ky7Uwd6iOLNxL3k0LttI/qHMrfh4/rNGFNpqXTzD72k=; b=gglWJtAiU5BPQ58tMR+CTCrOgXS5JHXAAdQJnh0hrNtu8zt2V1yu5v58zq2AqC6qtO PNGtPABPuXd/ga7X2LgjHLJHNnSYgIkLvJNtvT5cbdORwKxZAGkdJDoxuVl6zBuEy6yX K0Zj5hoTMv17tgnWL9B/OjbFSoUu4vlyHWZOuYteINRwGm++r1nQeT5AdavNGO/E8MrG ndpj1NgMJKcQJ9z0S4wFONE8KMaOo/4xAHWrfNhq42kEsvRBjD4j+p0snkxhR0KqqUOk 0GT/NoMzPcV4uY5ga+7BAPAwBYVAjeWJO/8rwqAdR04VXlfC2hWLkIgHd3HNYuULv53R YVXg== X-Gm-Message-State: AOAM530QFEyGLdt03DVB93RvA7nk7OaH593dWajSGw1r5x5lh8WxPO2t hG6bxU74PPfRGXx1fMBThIGiszye0MLdPA== X-Google-Smtp-Source: ABdhPJxj77WW/WfzDQ9ZOeDxJ7QkLoiCUA3WextVubpq4EhnoiAIsgFsLXdAOdhZj23Zs0G/1frm8g== X-Received: by 2002:ac2:47eb:: with SMTP id b11mr4519679lfp.165.1594982139754; Fri, 17 Jul 2020 03:35:39 -0700 (PDT) Received: from cloudflare.com ([2a02:a310:c262:aa00:b35e:8938:2c2a:ba8b]) by smtp.gmail.com with ESMTPSA id p8sm1871618ljn.117.2020.07.17.03.35.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Jul 2020 03:35:38 -0700 (PDT) From: Jakub Sitnicki To: bpf@vger.kernel.org Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com, Alexei Starovoitov , Daniel Borkmann , "David S. Miller" , Jakub Kicinski , Andrii Nakryiko Subject: [PATCH bpf-next v5 01/15] bpf, netns: Handle multiple link attachments Date: Fri, 17 Jul 2020 12:35:22 +0200 Message-Id: <20200717103536.397595-2-jakub@cloudflare.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200717103536.397595-1-jakub@cloudflare.com> References: <20200717103536.397595-1-jakub@cloudflare.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Extend the BPF netns link callbacks to rebuild (grow/shrink) or update the prog_array at given position when link gets attached/updated/released. This let's us lift the limit of having just one link attached for the new attach type introduced by subsequent patch. No functional changes intended. Acked-by: Andrii Nakryiko Signed-off-by: Jakub Sitnicki --- Notes: v4: - Document prog_array {delete_safe,update}_at() behavior. (Andrii) - Return -EINVAL/-ENOENT on failure in {delete_safe,update}_at(). (Andrii) - Return -ENOENT on index out of range in link_index(). (Andrii) v3: - New in v3 to support multi-prog attachments. (Alexei) include/linux/bpf.h | 3 ++ kernel/bpf/core.c | 55 +++++++++++++++++++++++ kernel/bpf/net_namespace.c | 90 ++++++++++++++++++++++++++++++++++---- 3 files changed, 139 insertions(+), 9 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 54ad426dbea1..c8c9eabcd106 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -928,6 +928,9 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array *progs, void bpf_prog_array_delete_safe(struct bpf_prog_array *progs, struct bpf_prog *old_prog); +int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index); +int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, + struct bpf_prog *prog); int bpf_prog_array_copy_info(struct bpf_prog_array *array, u32 *prog_ids, u32 request_cnt, u32 *prog_cnt); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 9df4cc9a2907..7be02e555ab9 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1958,6 +1958,61 @@ void bpf_prog_array_delete_safe(struct bpf_prog_array *array, } } +/** + * bpf_prog_array_delete_safe_at() - Replaces the program at the given + * index into the program array with + * a dummy no-op program. + * @array: a bpf_prog_array + * @index: the index of the program to replace + * + * Skips over dummy programs, by not counting them, when calculating + * the the position of the program to replace. + * + * Return: + * * 0 - Success + * * -EINVAL - Invalid index value. Must be a non-negative integer. + * * -ENOENT - Index out of range + */ +int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) +{ + return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); +} + +/** + * bpf_prog_array_update_at() - Updates the program at the given index + * into the program array. + * @array: a bpf_prog_array + * @index: the index of the program to update + * @prog: the program to insert into the array + * + * Skips over dummy programs, by not counting them, when calculating + * the position of the program to update. + * + * Return: + * * 0 - Success + * * -EINVAL - Invalid index value. Must be a non-negative integer. + * * -ENOENT - Index out of range + */ +int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, + struct bpf_prog *prog) +{ + struct bpf_prog_array_item *item; + + if (unlikely(index < 0)) + return -EINVAL; + + for (item = array->items; item->prog; item++) { + if (item->prog == &dummy_bpf_prog.prog) + continue; + if (!index) { + WRITE_ONCE(item->prog, prog); + return 0; + } + index--; + } + return -ENOENT; +} + int bpf_prog_array_copy(struct bpf_prog_array *old_array, struct bpf_prog *exclude_prog, struct bpf_prog *include_prog, diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c index 310241ca7991..e9c8e26ac8f2 100644 --- a/kernel/bpf/net_namespace.c +++ b/kernel/bpf/net_namespace.c @@ -36,12 +36,50 @@ static void netns_bpf_run_array_detach(struct net *net, bpf_prog_array_free(run_array); } +static int link_index(struct net *net, enum netns_bpf_attach_type type, + struct bpf_netns_link *link) +{ + struct bpf_netns_link *pos; + int i = 0; + + list_for_each_entry(pos, &net->bpf.links[type], node) { + if (pos == link) + return i; + i++; + } + return -ENOENT; +} + +static int link_count(struct net *net, enum netns_bpf_attach_type type) +{ + struct list_head *pos; + int i = 0; + + list_for_each(pos, &net->bpf.links[type]) + i++; + return i; +} + +static void fill_prog_array(struct net *net, enum netns_bpf_attach_type type, + struct bpf_prog_array *prog_array) +{ + struct bpf_netns_link *pos; + unsigned int i = 0; + + list_for_each_entry(pos, &net->bpf.links[type], node) { + prog_array->items[i].prog = pos->link.prog; + i++; + } +} + static void bpf_netns_link_release(struct bpf_link *link) { struct bpf_netns_link *net_link = container_of(link, struct bpf_netns_link, link); enum netns_bpf_attach_type type = net_link->netns_type; + struct bpf_prog_array *old_array, *new_array; struct net *net; + int cnt, idx; mutex_lock(&netns_bpf_mutex); @@ -53,9 +91,27 @@ static void bpf_netns_link_release(struct bpf_link *link) if (!net) goto out_unlock; - netns_bpf_run_array_detach(net, type); + /* Remember link position in case of safe delete */ + idx = link_index(net, type, net_link); list_del(&net_link->node); + cnt = link_count(net, type); + if (!cnt) { + netns_bpf_run_array_detach(net, type); + goto out_unlock; + } + + old_array = rcu_dereference_protected(net->bpf.run_array[type], + lockdep_is_held(&netns_bpf_mutex)); + new_array = bpf_prog_array_alloc(cnt, GFP_KERNEL); + if (!new_array) { + WARN_ON(bpf_prog_array_delete_safe_at(old_array, idx)); + goto out_unlock; + } + fill_prog_array(net, type, new_array); + rcu_assign_pointer(net->bpf.run_array[type], new_array); + bpf_prog_array_free(old_array); + out_unlock: mutex_unlock(&netns_bpf_mutex); } @@ -77,7 +133,7 @@ static int bpf_netns_link_update_prog(struct bpf_link *link, enum netns_bpf_attach_type type = net_link->netns_type; struct bpf_prog_array *run_array; struct net *net; - int ret = 0; + int idx, ret; if (old_prog && old_prog != link->prog) return -EPERM; @@ -95,7 +151,10 @@ static int bpf_netns_link_update_prog(struct bpf_link *link, run_array = rcu_dereference_protected(net->bpf.run_array[type], lockdep_is_held(&netns_bpf_mutex)); - WRITE_ONCE(run_array->items[0].prog, new_prog); + idx = link_index(net, type, net_link); + ret = bpf_prog_array_update_at(run_array, idx, new_prog); + if (ret) + goto out_unlock; old_prog = xchg(&link->prog, new_prog); bpf_prog_put(old_prog); @@ -309,18 +368,28 @@ int netns_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) return ret; } +static int netns_bpf_max_progs(enum netns_bpf_attach_type type) +{ + switch (type) { + case NETNS_BPF_FLOW_DISSECTOR: + return 1; + default: + return 0; + } +} + static int netns_bpf_link_attach(struct net *net, struct bpf_link *link, enum netns_bpf_attach_type type) { struct bpf_netns_link *net_link = container_of(link, struct bpf_netns_link, link); struct bpf_prog_array *run_array; - int err; + int cnt, err; mutex_lock(&netns_bpf_mutex); - /* Allow attaching only one prog or link for now */ - if (!list_empty(&net->bpf.links[type])) { + cnt = link_count(net, type); + if (cnt >= netns_bpf_max_progs(type)) { err = -E2BIG; goto out_unlock; } @@ -341,16 +410,19 @@ static int netns_bpf_link_attach(struct net *net, struct bpf_link *link, if (err) goto out_unlock; - run_array = bpf_prog_array_alloc(1, GFP_KERNEL); + run_array = bpf_prog_array_alloc(cnt + 1, GFP_KERNEL); if (!run_array) { err = -ENOMEM; goto out_unlock; } - run_array->items[0].prog = link->prog; - rcu_assign_pointer(net->bpf.run_array[type], run_array); list_add_tail(&net_link->node, &net->bpf.links[type]); + fill_prog_array(net, type, run_array); + run_array = rcu_replace_pointer(net->bpf.run_array[type], run_array, + lockdep_is_held(&netns_bpf_mutex)); + bpf_prog_array_free(run_array); + out_unlock: mutex_unlock(&netns_bpf_mutex); return err; -- 2.25.4