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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 962A4C433E1 for ; Thu, 20 Aug 2020 20:29:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 59F22207DE for ; Thu, 20 Aug 2020 20:29:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="wUs8aulE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728341AbgHTU3e (ORCPT ); Thu, 20 Aug 2020 16:29:34 -0400 Received: from mail.zx2c4.com ([192.95.5.64]:33773 "EHLO mail.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726908AbgHTU3b (ORCPT ); Thu, 20 Aug 2020 16:29:31 -0400 Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 6eebc9dc; Thu, 20 Aug 2020 20:03:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=mime-version :in-reply-to:references:from:date:message-id:subject:to:cc :content-type; s=mail; bh=vbB12wcoqGij8pNjbTWmmp+jHvY=; b=wUs8au lE4biNqHYhGliEHSQHFFLxEWY9JK5D3fy0wIB5+PTA1mWWxXL0IFPECmgrvwdMkl Ewys71yT2/SchWAbsGurH0rikrqWivc/7rHZ4Ie9ghMwEbKsfTnBIXCXhobobuJU obUr6B2hY9kDOSrPJOCXXWdD3aLfsYxOJDaJAqMvVbrziYgeMLbU4UCEnvVkcxys JIQpuuc+/rl8KI6xD+oCU7WjAge6x7vROtGA4diV8IDKYC5vHDincOFzm+ReN2lS VdeEim8JmC3VPmR/NOXeJpeTeEnDg2JDl3CsJOg7MmP2xu3w7iO+UhkW+rgiD5xC 4SEiHWuayPrDwEDg== Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id aa7c0c0b (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 20 Aug 2020 20:02:59 +0000 (UTC) Received: by mail-il1-f179.google.com with SMTP id 77so2780107ilc.5; Thu, 20 Aug 2020 13:29:28 -0700 (PDT) X-Gm-Message-State: AOAM533AfpcTOqXq/M+VL612QGJGxX0BUUzFGFWehSgTQOadb3zr+O3m JOlGiI3OOTUy63xOvE3Fp60AShVZzYgYjw4XE5w= X-Google-Smtp-Source: ABdhPJxYAN5teeI+8iuarY1p5HV0KRkx/xSmiz39Aszl4gAfKEvCJyq1qzz5qPsVx8Vjx6yv+lbqRx1SMAobfZvt8H0= X-Received: by 2002:a92:cf09:: with SMTP id c9mr364213ilo.38.1597955367170; Thu, 20 Aug 2020 13:29:27 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a05:6e02:ed0:0:0:0:0 with HTTP; Thu, 20 Aug 2020 13:29:26 -0700 (PDT) In-Reply-To: <20200820.115512.511642239854628332.davem@davemloft.net> References: <20200815074102.5357-1-Jason@zx2c4.com> <20200819.162247.527509541688231611.davem@davemloft.net> <20200820.115512.511642239854628332.davem@davemloft.net> From: "Jason A. Donenfeld" Date: Thu, 20 Aug 2020 22:29:26 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH net v6] net: xdp: account for layer 3 packets in generic skb handler To: David Miller Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, thomas@sockpuppet.org, adhipati@tuta.io, dsahern@gmail.com, toke@redhat.com, kuba@kernel.org, alexei.starovoitov@gmail.com, brouer@redhat.com, john.fastabend@gmail.com, daniel@iogearbox.net Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 8/20/20, David Miller wrote: > From: "Jason A. Donenfeld" > Date: Thu, 20 Aug 2020 11:13:49 +0200 > >> It seems like if an eBPF program pushes on a VLAN tag or changes the >> protocol or does any other modification, it will be treated in exactly >> the same way as the L2 packet above by the remaining parts of the >> networking stack. > > What will update the skb metadata if the XDP program changes the > wireguard header(s)? > XDP runs after decryption/decapsulation, in the netif_rx path, which means there is no wireguard header at that point. All the wireguard crypto/udp/header stuff is all inside the driver itself, and the rest of the stack just deals in terms of plain vanilla L3 ipv4/ipv6 packets. The skb->protocol metadata is handled by the fake ethernet header. Is there other metadata I should keep in mind? WireGuard doesn't play with skb_metadata_*, for example. (Though it may implicitly reach a skb_metadata_clear via pskb_expand path.)