From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8DA05218E92; Wed, 9 Apr 2025 21:46:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744235174; cv=none; b=rlmBZwVJDysuKjP/EvDHIX5YojQT6wc5+Itr3WrhPQkVAhwM69Q8o2PXl0XBDtYGujYMuXpJ9l7XGhk2NZZVu+8tjnc1gDIMzjt8JumhHh07c5ZSSCm3Pdce6hFOg28k6aU0/C4op35iqDcKMy/8LRZ+trixBQLGy1IBctC4zRg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744235174; c=relaxed/simple; bh=HtpmPOfCekbXG4UayHfNUkrx4xFGghDA7+xcxJ/7hSk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=vGBMlApGBL1fTl5eFOfU+b6ybwtx0gpsTitqgIf5AAPoTB9z/BztwA42ySoGgU76zZMkhYL4sn2Elmlrljm55/WLme4y2AX+4C9l1b7Amb/Ys/k48wbr6AZ+X9YOhgZ1ylsC3l/qnWSaumykUg39JCN6zw24WAOjzSl35JgD4Wo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=DJc1SjD2; arc=none smtp.client-ip=209.85.214.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="DJc1SjD2" Received: by mail-pl1-f179.google.com with SMTP id d9443c01a7336-2264aefc45dso1893545ad.0; Wed, 09 Apr 2025 14:46:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1744235171; x=1744839971; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=fhvff8xITZZMdar9HZn0Dny8IHdsn0Mdqy7WvvccQvQ=; b=DJc1SjD2U18rFsKZv+S8ZdkCqOWETwAYT+eSh6S7ALby0tB/SH1Mj6xkkIrIhd5CZR a0sQHGtpL5tVAHgfXHS0NFkUCAQ60bq2WEln3vSEzv/S2nkZTURsp8gwrAhojT+0hNIt sjcD/9mQnzoEIwe7l5YduM8Yh5Cy4fXtlWJv522ItffNzdpapjROAwiPy4Jqz6Qlj7ef KdJ08wj+eooV8y49Wd2rJFXhAIPwWZdOAjdWsz42lOouc5JjKAzsbF8Y8cKQhGetNKTl SOcrofaC5RixqrhoEBnuPNLwoaFGkxCt/1vqugGj4bUxGz8qZJ70GnRLsZGy5XZ3yB+C Nhbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744235171; x=1744839971; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=fhvff8xITZZMdar9HZn0Dny8IHdsn0Mdqy7WvvccQvQ=; b=JvR138+qkA2fcD5e4EzOP0gQ6prEKJKSSJknChfXUUszyZDfJSShF5ldUkNl0KnE5C 5HBOTOupn0Y8FEO+r1z400e1MO6JHNJpk073OhSR9RsIIwDzthnET0BqG4Tcv7p1HoKq 4f75CMMz3wKHeQpc3RpfGycEIwK7uU28+78XoD4eFOjTwr5dJVSduso1JuxktTkUnQzX JeqcseF4Wt+aOjP8K8V7xaaGIqe2peOcjp28nT5FFPt8RBryQg+t2ZPaJ2DiSVxxUZmk YXZtROpfuiT0EUDdLoYMFph4GcDz92m4eR+66FAXaRTLVHEx1wubHg61O9bHL1D1y0Cv FPXw== X-Gm-Message-State: AOJu0YzxAYIHM/U0KIr46uQ989v5YVNFEVdmVezLzOCFobIx7WTd9PSu q3DnDy1S0T5ET9cy2whTXpFFYgLIZq0E6S7jBSzfiUzo4VMOq3vKSuxeewBS X-Gm-Gg: ASbGncsaLBVZmv15JlhKCBH/ml69gLKP+6ieXIzUcaMjiC1cWb/AUJ0h+TN65Q7mmtr q/9cNdP667/tWtlPGSSIPPzi5lbU7Fz5rocKy9L97vuaFYOMKiNxipt0AWJi+VCki6u0ulI98J2 H1qZg91azRBN2nGM55OECasCMXSneWW1sSY9GewLm7sPa9DQ/iKQIIpJPRw7H+L/BiRi6YTccpB VAwCbmGmkvWGwywPRnv2mgI6aqeZzschjbxOA1tYD18pMdOYOoKhNHlEdzNfNlzXGrrUhUlyCFQ pwX+pajRmak9Zrfl0FklKm2BP7ps X-Google-Smtp-Source: AGHT+IFmXKyOzdXQn1H9izB+vFA1ys1tHlNVWFdP2LA+S9r8mEbbN0QueMdEZFJdepNGyfohrV8Nsw== X-Received: by 2002:a17:902:d48f:b0:224:376:7a21 with SMTP id d9443c01a7336-22b42ca8b8fmr4598645ad.42.1744235171562; Wed, 09 Apr 2025 14:46:11 -0700 (PDT) Received: from localhost ([2a03:2880:ff::]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-73bb1d465d7sm1866589b3a.47.2025.04.09.14.46.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Apr 2025 14:46:11 -0700 (PDT) From: Amery Hung To: bpf@vger.kernel.org Cc: netdev@vger.kernel.org, alexei.starovoitov@gmail.com, andrii@kernel.org, daniel@iogearbox.net, edumazet@google.com, kuba@kernel.org, xiyou.wangcong@gmail.com, jhs@mojatatu.com, martin.lau@kernel.org, jiri@resnulli.us, stfomichev@gmail.com, toke@redhat.com, sinquersw@gmail.com, ekarani.silvestre@ccc.ufcg.edu.br, yangpeihao@sjtu.edu.cn, yepeilin.cs@gmail.com, kernel-team@meta.com Subject: [PATCH bpf-next v7 03/10] bpf: net_sched: Add basic bpf qdisc kfuncs Date: Wed, 9 Apr 2025 14:45:59 -0700 Message-ID: <20250409214606.2000194-4-ameryhung@gmail.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250409214606.2000194-1-ameryhung@gmail.com> References: <20250409214606.2000194-1-ameryhung@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Amery Hung Add basic kfuncs for working on skb in qdisc. Both bpf_qdisc_skb_drop() and bpf_kfree_skb() can be used to release a reference to an skb. However, bpf_qdisc_skb_drop() can only be called in .enqueue where a to_free skb list is available from kernel to defer the release. bpf_kfree_skb() should be used elsewhere. It is also used in bpf_obj_free_fields() when cleaning up skb in maps and collections. bpf_skb_get_hash() returns the flow hash of an skb, which can be used to build flow-based queueing algorithms. Finally, allow users to create read-only dynptr via bpf_dynptr_from_skb(). Signed-off-by: Amery Hung Acked-by: Toke Høiland-Jørgensen --- net/sched/bpf_qdisc.c | 111 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 110 insertions(+), 1 deletion(-) diff --git a/net/sched/bpf_qdisc.c b/net/sched/bpf_qdisc.c index 7eca556a3782..d812a72ca032 100644 --- a/net/sched/bpf_qdisc.c +++ b/net/sched/bpf_qdisc.c @@ -8,6 +8,9 @@ #include #include +#define QDISC_OP_IDX(op) (offsetof(struct Qdisc_ops, op) / sizeof(void (*)(void))) +#define QDISC_MOFF_IDX(moff) (moff / sizeof(void (*)(void))) + static struct bpf_struct_ops bpf_Qdisc_ops; struct bpf_sk_buff_ptr { @@ -139,6 +142,95 @@ static int bpf_qdisc_btf_struct_access(struct bpf_verifier_log *log, return 0; } +__bpf_kfunc_start_defs(); + +/* bpf_skb_get_hash - Get the flow hash of an skb. + * @skb: The skb to get the flow hash from. + */ +__bpf_kfunc u32 bpf_skb_get_hash(struct sk_buff *skb) +{ + return skb_get_hash(skb); +} + +/* bpf_kfree_skb - Release an skb's reference and drop it immediately. + * @skb: The skb whose reference to be released and dropped. + */ +__bpf_kfunc void bpf_kfree_skb(struct sk_buff *skb) +{ + kfree_skb(skb); +} + +/* bpf_qdisc_skb_drop - Drop an skb by adding it to a deferred free list. + * @skb: The skb whose reference to be released and dropped. + * @to_free_list: The list of skbs to be dropped. + */ +__bpf_kfunc void bpf_qdisc_skb_drop(struct sk_buff *skb, + struct bpf_sk_buff_ptr *to_free_list) +{ + __qdisc_drop(skb, (struct sk_buff **)to_free_list); +} + +__bpf_kfunc_end_defs(); + +BTF_KFUNCS_START(qdisc_kfunc_ids) +BTF_ID_FLAGS(func, bpf_skb_get_hash, KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_kfree_skb, KF_RELEASE) +BTF_ID_FLAGS(func, bpf_qdisc_skb_drop, KF_RELEASE) +BTF_ID_FLAGS(func, bpf_dynptr_from_skb, KF_TRUSTED_ARGS) +BTF_KFUNCS_END(qdisc_kfunc_ids) + +BTF_SET_START(qdisc_common_kfunc_set) +BTF_ID(func, bpf_skb_get_hash) +BTF_ID(func, bpf_kfree_skb) +BTF_ID(func, bpf_dynptr_from_skb) +BTF_SET_END(qdisc_common_kfunc_set) + +BTF_SET_START(qdisc_enqueue_kfunc_set) +BTF_ID(func, bpf_qdisc_skb_drop) +BTF_SET_END(qdisc_enqueue_kfunc_set) + +enum qdisc_ops_kf_flags { + QDISC_OPS_KF_COMMON = 0, + QDISC_OPS_KF_ENQUEUE = 1 << 0, +}; + +static const u32 qdisc_ops_context_flags[] = { + [QDISC_OP_IDX(enqueue)] = QDISC_OPS_KF_ENQUEUE, + [QDISC_OP_IDX(dequeue)] = QDISC_OPS_KF_COMMON, + [QDISC_OP_IDX(init)] = QDISC_OPS_KF_COMMON, + [QDISC_OP_IDX(reset)] = QDISC_OPS_KF_COMMON, + [QDISC_OP_IDX(destroy)] = QDISC_OPS_KF_COMMON, +}; + +static int bpf_qdisc_kfunc_filter(const struct bpf_prog *prog, u32 kfunc_id) +{ + u32 moff, flags; + + if (!btf_id_set8_contains(&qdisc_kfunc_ids, kfunc_id)) + return 0; + + if (prog->aux->st_ops != &bpf_Qdisc_ops) + return -EACCES; + + moff = prog->aux->attach_st_ops_member_off; + flags = qdisc_ops_context_flags[QDISC_MOFF_IDX(moff)]; + + if ((flags & QDISC_OPS_KF_ENQUEUE) && + btf_id_set_contains(&qdisc_enqueue_kfunc_set, kfunc_id)) + return 0; + + if (btf_id_set_contains(&qdisc_common_kfunc_set, kfunc_id)) + return 0; + + return -EACCES; +} + +static const struct btf_kfunc_id_set bpf_qdisc_kfunc_set = { + .owner = THIS_MODULE, + .set = &qdisc_kfunc_ids, + .filter = bpf_qdisc_kfunc_filter, +}; + static const struct bpf_verifier_ops bpf_qdisc_verifier_ops = { .get_func_proto = bpf_base_func_proto, .is_valid_access = bpf_qdisc_is_valid_access, @@ -225,8 +317,25 @@ static struct bpf_struct_ops bpf_Qdisc_ops = { .owner = THIS_MODULE, }; +BTF_ID_LIST(bpf_sk_buff_dtor_ids) +BTF_ID(func, bpf_kfree_skb) + static int __init bpf_qdisc_kfunc_init(void) { - return register_bpf_struct_ops(&bpf_Qdisc_ops, Qdisc_ops); + int ret; + const struct btf_id_dtor_kfunc skb_kfunc_dtors[] = { + { + .btf_id = bpf_sk_buff_ids[0], + .kfunc_btf_id = bpf_sk_buff_dtor_ids[0] + }, + }; + + ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_qdisc_kfunc_set); + ret = ret ?: register_btf_id_dtor_kfuncs(skb_kfunc_dtors, + ARRAY_SIZE(skb_kfunc_dtors), + THIS_MODULE); + ret = ret ?: register_bpf_struct_ops(&bpf_Qdisc_ops, Qdisc_ops); + + return ret; } late_initcall(bpf_qdisc_kfunc_init); -- 2.47.1