From patchwork Mon Mar 13 19:08:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Lobakin X-Patchwork-Id: 13177185 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D515AC6FD19 for ; Thu, 16 Mar 2023 08:24:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230179AbjCPIYp (ORCPT ); Thu, 16 Mar 2023 04:24:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230115AbjCPIYn (ORCPT ); Thu, 16 Mar 2023 04:24:43 -0400 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 114F9AFB84; Thu, 16 Mar 2023 01:24:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678955082; x=1710491082; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=q3tc4GYyiOU2uNgooS6P06z+EYUuo4vPnkgkpRpdBNI=; b=c/reK+tEiAvhuFGhhVCqhjRg3iJkMuCUILjdxFZdHblaALvmUzmQiFVv FTGXzxYzduLriLvo0zwLXi0IDCTNcVNrKPUClsNPyCCH8uFMT78mlIPq7 F85kkaY/FMWIUuOlQQm4WNIFeaXAhIAw4dVkppszvSoHvdcYHlHLQRrok M+q7A2LdBLr2dlfTI8LKP8JOoYk3B8guECmWm4em4LmuUakRtfMTkVhHP 7w4XGeuiMxbaTvyyi5eAxtMSHlZQG7J0PQ3zolny68+77p4G3OEbLTOSA wjcz0Cx8tMWBESUCtKAjWQ5mQH8ulavjhE6RmM0BJCiafsBRUrgtl4XuV w==; X-IronPort-AV: E=McAfee;i="6500,9779,10650"; a="402794211" X-IronPort-AV: E=Sophos;i="5.98,265,1673942400"; d="scan'208";a="402794211" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2023 01:24:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10650"; a="823141548" X-IronPort-AV: E=Sophos;i="5.98,265,1673942400"; d="scan'208";a="823141548" Received: from irvmail002.ir.intel.com ([10.43.11.120]) by fmsmga001.fm.intel.com with ESMTP; 16 Mar 2023 01:24:37 -0700 Received: from newjersey.igk.intel.com (newjersey.igk.intel.com [10.102.20.203]) by irvmail002.ir.intel.com (Postfix) with ESMTP id 14A3B7525C; Mon, 13 Mar 2023 19:09:41 +0000 (GMT) From: Alexander Lobakin To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau Cc: Alexander Lobakin , Maciej Fijalkowski , Larysa Zaremba , =?utf-8?q?Toke_H=C3=B8iland-J?= =?utf-8?q?=C3=B8rgensen?= , Song Liu , Jesper Dangaard Brouer , John Fastabend , Menglong Dong , Mykola Lysenko , "David S. Miller" , Jakub Kicinski , Eric Dumazet , Paolo Abeni , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next v3 1/4] selftests/bpf: robustify test_xdp_do_redirect with more payload magics Date: Mon, 13 Mar 2023 20:08:10 +0100 Message-Id: <20230313190813.1036595-2-aleksander.lobakin@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230313190813.1036595-1-aleksander.lobakin@intel.com> References: <20230313190813.1036595-1-aleksander.lobakin@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Currently, the test relies on that only dropped ("xmitted") frames will be recycled and if a frame became an skb, it will be freed later by the stack and never come back to its page_pool. So, it easily gets broken by trying to recycle skbs[0]: test_xdp_do_redirect:PASS:pkt_count_xdp 0 nsec test_xdp_do_redirect:FAIL:pkt_count_zero unexpected pkt_count_zero: actual 9936 != expected 2 test_xdp_do_redirect:PASS:pkt_count_tc 0 nsec That huge mismatch happened because after the TC ingress hook zeroes the magic, the page gets recycled when skb is freed, not returned to the MM layer. "Live frames" mode initializes only new pages and keeps the recycled ones as is by design, so they appear with zeroed magic on the Rx path again. Expand the possible magic values from two: 0 (was "xmitted"/dropped or did hit the TC hook) and 0x42 (hit the input XDP prog) to three: the new one will mark frames hit the TC hook, so that they will elide both @pkt_count_zero and @pkt_count_xdp. They can then be recycled to their page_pool or returned to the page allocator, this won't affect the counters anyhow. Just make sure to mark them as "input" (0x42) when they appear on the Rx path again. Also make an enum from those magics, so that they will be always visible and can be changed in just one place anytime. This also eases adding any new marks later on. Link: https://github.com/kernel-patches/bpf/actions/runs/4386538411/jobs/7681081789 Signed-off-by: Alexander Lobakin --- .../bpf/progs/test_xdp_do_redirect.c | 36 +++++++++++++------ 1 file changed, 26 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c b/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c index 77a123071940..cd2d4e3258b8 100644 --- a/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c +++ b/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c @@ -4,6 +4,19 @@ #define ETH_ALEN 6 #define HDR_SZ (sizeof(struct ethhdr) + sizeof(struct ipv6hdr) + sizeof(struct udphdr)) + +/** + * enum frame_mark - magics to distinguish page/packet paths + * @MARK_XMIT: page was recycled due to the frame being "xmitted" by the NIC. + * @MARK_IN: frame is being processed by the input XDP prog. + * @MARK_SKB: frame did hit the TC ingress hook as an skb. + */ +enum frame_mark { + MARK_XMIT = 0U, + MARK_IN = 0x42, + MARK_SKB = 0x45, +}; + const volatile int ifindex_out; const volatile int ifindex_in; const volatile __u8 expect_dst[ETH_ALEN]; @@ -34,10 +47,10 @@ int xdp_redirect(struct xdp_md *xdp) if (*metadata != 0x42) return XDP_ABORTED; - if (*payload == 0) { - *payload = 0x42; + if (*payload == MARK_XMIT) pkts_seen_zero++; - } + + *payload = MARK_IN; if (bpf_xdp_adjust_meta(xdp, 4)) return XDP_ABORTED; @@ -51,7 +64,7 @@ int xdp_redirect(struct xdp_md *xdp) return ret; } -static bool check_pkt(void *data, void *data_end) +static bool check_pkt(void *data, void *data_end, const __u32 mark) { struct ipv6hdr *iph = data + sizeof(struct ethhdr); __u8 *payload = data + HDR_SZ; @@ -59,13 +72,13 @@ static bool check_pkt(void *data, void *data_end) if (payload + 1 > data_end) return false; - if (iph->nexthdr != IPPROTO_UDP || *payload != 0x42) + if (iph->nexthdr != IPPROTO_UDP || *payload != MARK_IN) return false; /* reset the payload so the same packet doesn't get counted twice when * it cycles back through the kernel path and out the dst veth */ - *payload = 0; + *payload = mark; return true; } @@ -75,11 +88,11 @@ int xdp_count_pkts(struct xdp_md *xdp) void *data = (void *)(long)xdp->data; void *data_end = (void *)(long)xdp->data_end; - if (check_pkt(data, data_end)) + if (check_pkt(data, data_end, MARK_XMIT)) pkts_seen_xdp++; - /* Return XDP_DROP to make sure the data page is recycled, like when it - * exits a physical NIC. Recycled pages will be counted in the + /* Return %XDP_DROP to recycle the data page with %MARK_XMIT, like + * it exited a physical NIC. Those pages will be counted in the * pkts_seen_zero counter above. */ return XDP_DROP; @@ -91,9 +104,12 @@ int tc_count_pkts(struct __sk_buff *skb) void *data = (void *)(long)skb->data; void *data_end = (void *)(long)skb->data_end; - if (check_pkt(data, data_end)) + if (check_pkt(data, data_end, MARK_SKB)) pkts_seen_tc++; + /* Will be either recycled or freed, %MARK_SKB makes sure it won't + * hit any of the counters above. + */ return 0; }