From patchwork Fri Feb 17 18:12:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin KaFai Lau X-Patchwork-Id: 13145118 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 7454EC636D6 for ; Fri, 17 Feb 2023 18:12:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229463AbjBQSMj (ORCPT ); Fri, 17 Feb 2023 13:12:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229591AbjBQSMh (ORCPT ); Fri, 17 Feb 2023 13:12:37 -0500 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 667BAEB4A; Fri, 17 Feb 2023 10:12:36 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1676657554; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=PwZEl/wTUxGr6miLXiGTMsN4b7aOUjpQuGXPVrDinoE=; b=LWN8t1utfMMIJM62G51S9NemwmLynRw+ergvQkN8rvtVFYlkd+TMLXacqMxiKojQXX6wec H6uZDcDMBpPeG3+JZAILVE58k0RosT2PEictoyFDQua/oM9CZHVR3FpNauVSFRc7my5haB 5BE8MslZ396platY1F/XCiCD3jcawq0= From: Martin KaFai Lau To: bpf@vger.kernel.org Cc: 'Alexei Starovoitov ' , 'Andrii Nakryiko ' , 'Daniel Borkmann ' , netdev@vger.kernel.org, kernel-team@meta.com Subject: [PATCH v2 bpf-next 1/2] bpf: Add BPF_FIB_LOOKUP_SKIP_NEIGH for bpf_fib_lookup Date: Fri, 17 Feb 2023 10:12:23 -0800 Message-Id: <20230217181224.2320704-1-martin.lau@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Martin KaFai Lau The bpf_fib_lookup() also looks up the neigh table. This was done before bpf_redirect_neigh() was added. In the use case that does not manage the neigh table and requires bpf_fib_lookup() to lookup a fib to decide if it needs to redirect or not, the bpf prog can depend only on using bpf_redirect_neigh() to lookup the neigh. It also keeps the neigh entries fresh and connected. This patch adds a bpf_fib_lookup flag, SKIP_NEIGH, to avoid the double neigh lookup when the bpf prog always call bpf_redirect_neigh() to do the neigh lookup. The params->smac output is skipped together when SKIP_NEIGH is set because bpf_redirect_neigh() will figure out the smac also. Signed-off-by: Martin KaFai Lau --- v2: - Skip copying smac when the SKIP_NEIGH is set - Keep the ordering of the (nhc->nhc_gw_family != AF_INET6) test include/uapi/linux/bpf.h | 1 + net/core/filter.c | 39 ++++++++++++++++++++++------------ tools/include/uapi/linux/bpf.h | 1 + 3 files changed, 28 insertions(+), 13 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 1503f61336b6..6c1956e36c97 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -6750,6 +6750,7 @@ struct bpf_raw_tracepoint_args { enum { BPF_FIB_LOOKUP_DIRECT = (1U << 0), BPF_FIB_LOOKUP_OUTPUT = (1U << 1), + BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2), }; enum { diff --git a/net/core/filter.c b/net/core/filter.c index 8daaaf76ab15..1d6f165923bf 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5722,12 +5722,8 @@ static const struct bpf_func_proto bpf_skb_get_xfrm_state_proto = { #endif #if IS_ENABLED(CONFIG_INET) || IS_ENABLED(CONFIG_IPV6) -static int bpf_fib_set_fwd_params(struct bpf_fib_lookup *params, - const struct neighbour *neigh, - const struct net_device *dev, u32 mtu) +static int bpf_fib_set_fwd_params(struct bpf_fib_lookup *params, u32 mtu) { - memcpy(params->dmac, neigh->ha, ETH_ALEN); - memcpy(params->smac, dev->dev_addr, ETH_ALEN); params->h_vlan_TCI = 0; params->h_vlan_proto = 0; if (mtu) @@ -5838,21 +5834,29 @@ static int bpf_ipv4_fib_lookup(struct net *net, struct bpf_fib_lookup *params, if (likely(nhc->nhc_gw_family != AF_INET6)) { if (nhc->nhc_gw_family) params->ipv4_dst = nhc->nhc_gw.ipv4; - - neigh = __ipv4_neigh_lookup_noref(dev, - (__force u32)params->ipv4_dst); } else { struct in6_addr *dst = (struct in6_addr *)params->ipv6_dst; params->family = AF_INET6; *dst = nhc->nhc_gw.ipv6; - neigh = __ipv6_neigh_lookup_noref_stub(dev, dst); } + if (flags & BPF_FIB_LOOKUP_SKIP_NEIGH) + goto set_fwd_params; + + if (likely(nhc->nhc_gw_family != AF_INET6)) + neigh = __ipv4_neigh_lookup_noref(dev, + (__force u32)params->ipv4_dst); + else + neigh = __ipv6_neigh_lookup_noref_stub(dev, params->ipv6_dst); + if (!neigh || !(neigh->nud_state & NUD_VALID)) return BPF_FIB_LKUP_RET_NO_NEIGH; + memcpy(params->dmac, neigh->ha, ETH_ALEN); + memcpy(params->smac, dev->dev_addr, ETH_ALEN); - return bpf_fib_set_fwd_params(params, neigh, dev, mtu); +set_fwd_params: + return bpf_fib_set_fwd_params(params, mtu); } #endif @@ -5960,24 +5964,33 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params, params->rt_metric = res.f6i->fib6_metric; params->ifindex = dev->ifindex; + if (flags & BPF_FIB_LOOKUP_SKIP_NEIGH) + goto set_fwd_params; + /* xdp and cls_bpf programs are run in RCU-bh so rcu_read_lock_bh is * not needed here. */ neigh = __ipv6_neigh_lookup_noref_stub(dev, dst); if (!neigh || !(neigh->nud_state & NUD_VALID)) return BPF_FIB_LKUP_RET_NO_NEIGH; + memcpy(params->dmac, neigh->ha, ETH_ALEN); + memcpy(params->smac, dev->dev_addr, ETH_ALEN); - return bpf_fib_set_fwd_params(params, neigh, dev, mtu); +set_fwd_params: + return bpf_fib_set_fwd_params(params, mtu); } #endif +#define BPF_FIB_LOOKUP_MASK (BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT | \ + BPF_FIB_LOOKUP_SKIP_NEIGH) + BPF_CALL_4(bpf_xdp_fib_lookup, struct xdp_buff *, ctx, struct bpf_fib_lookup *, params, int, plen, u32, flags) { if (plen < sizeof(*params)) return -EINVAL; - if (flags & ~(BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT)) + if (flags & ~BPF_FIB_LOOKUP_MASK) return -EINVAL; switch (params->family) { @@ -6015,7 +6028,7 @@ BPF_CALL_4(bpf_skb_fib_lookup, struct sk_buff *, skb, if (plen < sizeof(*params)) return -EINVAL; - if (flags & ~(BPF_FIB_LOOKUP_DIRECT | BPF_FIB_LOOKUP_OUTPUT)) + if (flags & ~BPF_FIB_LOOKUP_MASK) return -EINVAL; if (params->tot_len) diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 1503f61336b6..6c1956e36c97 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -6750,6 +6750,7 @@ struct bpf_raw_tracepoint_args { enum { BPF_FIB_LOOKUP_DIRECT = (1U << 0), BPF_FIB_LOOKUP_OUTPUT = (1U << 1), + BPF_FIB_LOOKUP_SKIP_NEIGH = (1U << 2), }; enum {