From patchwork Mon Mar 17 10:57:53 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akihiko Odaki X-Patchwork-Id: 14019001 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-pl1-f178.google.com (mail-pl1-f178.google.com [209.85.214.178]) (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 D6E312356AA for ; Mon, 17 Mar 2025 10:58:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742209109; cv=none; b=TtO2Mtg/fN2e8oCVT7Ox1BcTOdrDRc2vxT6znwL3pFKSLFjp43z2qoKSARepOvG9xO1QKrKV45J6XesRplyHsplTzYRrLWqRPL+XJ88GbrrxM/MiS9AmsIvNTjflXJBIX/6NNvIPeU78Xpq38Wu8SWpXO+MNGeYmR7TBdgZvbE0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742209109; c=relaxed/simple; bh=uj6BiB0IqVm8+xs3f9Zn6aCjK6f7zlPp0hv2djTMvTQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To; b=YDvdrcApE6xgw9atv9SFXr9HaNdv4rnx8h/G9L2YfeBZhskVqzVt+Uzwtwl4B2yYkSAPxZsRNblHmoXSHBPfIrJsRmy2Gg+91u8MyIjyJkezRRU/UA9FokGBK/5WNgVItM6ZkGYCNuWv1NsGQx0NlWVU/bFUA3YsZIHTxGvb4Pc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=daynix.com; spf=pass smtp.mailfrom=daynix.com; dkim=pass (2048-bit key) header.d=daynix-com.20230601.gappssmtp.com header.i=@daynix-com.20230601.gappssmtp.com header.b=JhDTdWnk; arc=none smtp.client-ip=209.85.214.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=daynix.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=daynix.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=daynix-com.20230601.gappssmtp.com header.i=@daynix-com.20230601.gappssmtp.com header.b="JhDTdWnk" Received: by mail-pl1-f178.google.com with SMTP id d9443c01a7336-226185948ffso11408205ad.0 for ; Mon, 17 Mar 2025 03:58:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=daynix-com.20230601.gappssmtp.com; s=20230601; t=1742209107; x=1742813907; darn=vger.kernel.org; h=to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=CFouu/EN4lEKQm+2Nyv7q163Sd7hDT7Qc+wcMAoVrxU=; b=JhDTdWnkWTengsPMPkeyo1QZCS6FfZIqiLpH6pIyZPbEP94MvsL4E8m7EPQp7W3sB/ l0rB2Z0KtyhrUIkHAql6I24dqGU6BIo5lz4bBFKbV/S/ITj3fWlRSb5KuTjbMdCj6Yk1 J98azBh0ZwLCy9hYuStfeVXLWAyAl6ankKLy3PlwmZv+tf64MZ2a+NBBAJZtZ7xrnmyY uFuwOe2CKnZ3aUiAGEnE4rmN1sV8iMrZmpYlP60F/KjumYzWFF3Or2tcO81+Cn94ueVU xeTiP2nYrx3B+Z8BNWPCyI5G9t9YdLbrc9sqnPFD5Ej/+jzoqRwdWm7itDmZ6ST3Rlfw exiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742209107; x=1742813907; h=to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=CFouu/EN4lEKQm+2Nyv7q163Sd7hDT7Qc+wcMAoVrxU=; b=Pz8FfOZSuLZXa9duaZc/t9i5q15zqLSiWcbrZZ9LaZqIlyKsmoN6WGG5zDTYPK6vk0 mi3HGTkrqUguTMQiHyM86Zkb3DXEM1LuwtUuyFg1JuEWP8O1Mn3Nsy1w1pUUZmX4CSXa amSP1Ey4rKGPXSwIUMms/PSQSnDB9ea7usMJE3ML1F8kzQufnHzFWiWRuzGfWUvYlmA6 Ymkqixmjm4GlI36h4o5n7UOOXEKdbOkQI3epApIW9IGTv4UxafpJyU5nrbHzpOGUEi6N JRvIZbDBKGLrALTE9/kG1m9WAhcRvSunFaOBI3sHUd6v/RVGsZcETaa0LhJZLsBsP7ad 8vvA== X-Forwarded-Encrypted: i=1; AJvYcCVvpe82G5uoKiKYsorOr4QSYHJgmXmIC/dp8AfJg2Ebyh/5NDfidB032Fvm7YAsHTFekWYFWVQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yy6DQhBL+4cXbhH/46wPWRXGJmFEvwFbrLjvMKhiea+IYmAzRZC t/fkZLiqc44yxjCEBFYkdZrZ8uPiwLAwM0zcT+sbyt4FtMOzWP8h2nQIcCW+CDI= X-Gm-Gg: ASbGncumxZsfUytUDva+wB2+E8ymR2W1kcPhplPyLrWoaOdQBmCXAXlfC684v+kidBs 6ZLfd+9YGoLmS/okuHULPgf0S0J/VQnbokJxgtQnsvrwm5R7FHfHv8/oeCHm2ZPcqdVXORUbSx5 76ey34tCe4WmSnGKoSdibFeDDkUleW/pLaArio6k9g0j5PmoSLFrKrgkokOCeaNDKWO57qPIfDo zJk/a4WcKY+NfooZdTbW4ev12ec5obbMIirFn4wiENHTQxb35A3EEtOzAGXdvnnD87bj1xQlgp2 JV0P9lgGtBHru99BSFjX4tC+6Jra9t1U1a42pLlZapgvHe3P X-Google-Smtp-Source: AGHT+IHGq79Rsv/kZfRVhSkItW1GnSGSGi4cX7skmUfl1fStmFO3ltKgY+5Iw+7Yo4D17wVag2aDMg== X-Received: by 2002:a17:902:d542:b0:223:58ff:c722 with SMTP id d9443c01a7336-225e0a75b3fmr179867305ad.28.1742209107158; Mon, 17 Mar 2025 03:58:27 -0700 (PDT) Received: from localhost ([157.82.207.107]) by smtp.gmail.com with UTF8SMTPSA id d9443c01a7336-225c68aa906sm72547105ad.88.2025.03.17.03.58.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Mar 2025 03:58:26 -0700 (PDT) From: Akihiko Odaki Date: Mon, 17 Mar 2025 19:57:53 +0900 Subject: [PATCH net-next v11 03/10] tun: Allow steering eBPF program to fall back Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250317-rss-v11-3-4cacca92f31f@daynix.com> References: <20250317-rss-v11-0-4cacca92f31f@daynix.com> In-Reply-To: <20250317-rss-v11-0-4cacca92f31f@daynix.com> To: Jonathan Corbet , Willem de Bruijn , Jason Wang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Michael S. Tsirkin" , Xuan Zhuo , Shuah Khan , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kselftest@vger.kernel.org, Yuri Benditovich , Andrew Melnychenko , Stephen Hemminger , gur.stavi@huawei.com, Lei Yang , Simon Horman , Akihiko Odaki X-Mailer: b4 0.15-dev-edae6 X-Patchwork-Delegate: kuba@kernel.org This clarifies a steering eBPF program takes precedence over the other steering algorithms. Signed-off-by: Akihiko Odaki --- Documentation/networking/tuntap.rst | 7 +++++++ drivers/net/tun.c | 28 +++++++++++++++++----------- include/uapi/linux/if_tun.h | 9 +++++++++ 3 files changed, 33 insertions(+), 11 deletions(-) diff --git a/Documentation/networking/tuntap.rst b/Documentation/networking/tuntap.rst index 4d7087f727be..86b4ae8caa8a 100644 --- a/Documentation/networking/tuntap.rst +++ b/Documentation/networking/tuntap.rst @@ -206,6 +206,13 @@ enable is true we enable it, otherwise we disable it:: return ioctl(fd, TUNSETQUEUE, (void *)&ifr); } +3.4 Reference +------------- + +``linux/if_tun.h`` defines the interface described below: + +.. kernel-doc:: include/uapi/linux/if_tun.h + Universal TUN/TAP device driver Frequently Asked Question ========================================================= diff --git a/drivers/net/tun.c b/drivers/net/tun.c index d8f4d3e996a7..9133ab9ed3f5 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -476,21 +476,29 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) return txq; } -static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb) +static bool tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb, + u16 *ret) { struct tun_prog *prog; u32 numqueues; - u16 ret = 0; + u32 prog_ret; + + prog = rcu_dereference(tun->steering_prog); + if (!prog) + return false; numqueues = READ_ONCE(tun->numqueues); - if (!numqueues) - return 0; + if (!numqueues) { + *ret = 0; + return true; + } - prog = rcu_dereference(tun->steering_prog); - if (prog) - ret = bpf_prog_run_clear_cb(prog->prog, skb); + prog_ret = bpf_prog_run_clear_cb(prog->prog, skb); + if (prog_ret == TUN_STEERINGEBPF_FALLBACK) + return false; - return ret % numqueues; + *ret = (u16)prog_ret % numqueues; + return true; } static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, @@ -500,9 +508,7 @@ static u16 tun_select_queue(struct net_device *dev, struct sk_buff *skb, u16 ret; rcu_read_lock(); - if (rcu_dereference(tun->steering_prog)) - ret = tun_ebpf_select_queue(tun, skb); - else + if (!tun_ebpf_select_queue(tun, skb, &ret)) ret = tun_automq_select_queue(tun, skb); rcu_read_unlock(); diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h index 287cdc81c939..980de74724fc 100644 --- a/include/uapi/linux/if_tun.h +++ b/include/uapi/linux/if_tun.h @@ -115,4 +115,13 @@ struct tun_filter { __u8 addr[][ETH_ALEN]; }; +/** + * define TUN_STEERINGEBPF_FALLBACK - A steering eBPF return value to fall back + * + * A steering eBPF program may return this value to fall back to the steering + * algorithm that should have been used if the program was not set. This allows + * selectively overriding the steering decision. + */ +#define TUN_STEERINGEBPF_FALLBACK -1 + #endif /* _UAPI__IF_TUN_H */