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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1E9FC4167B for ; Mon, 15 Nov 2021 18:34:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9942761266 for ; Mon, 15 Nov 2021 18:34:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242439AbhKOSgx (ORCPT ); Mon, 15 Nov 2021 13:36:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:46732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238305AbhKOReZ (ORCPT ); Mon, 15 Nov 2021 12:34:25 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6BF03632CB; Mon, 15 Nov 2021 17:23:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636996982; bh=58kZ2qfqicAyiU2+TYrKL580Mk+M/xXLLGl8frUbDMk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vlo3ak3TZ0d7wfjOlEFJ6HFL7pI4EoB73SXVdxaTSoM+EPqQ585M3xvyEXStzQUo7 MEvEQXOCNQnCE0tZRMxaOdgudCVpnCe9TrjVbIyKzHGLtgBnAGIoCYHmlWLpiJKK0J GmmfeXDF9A67Ysv3WB7+kIrF1YkQx/CI1J/UVecw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Borkmann , Roopa Prabhu , "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 339/355] net, neigh: Enable state migration between NUD_PERMANENT and NTF_USE Date: Mon, 15 Nov 2021 18:04:23 +0100 Message-Id: <20211115165324.708917202@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165313.549179499@linuxfoundation.org> References: <20211115165313.549179499@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Daniel Borkmann [ Upstream commit 3dc20f4762c62d3b3f0940644881ed818aa7b2f5 ] Currently, it is not possible to migrate a neighbor entry between NUD_PERMANENT state and NTF_USE flag with a dynamic NUD state from a user space control plane. Similarly, it is not possible to add/remove NTF_EXT_LEARNED flag from an existing neighbor entry in combination with NTF_USE flag. This is due to the latter directly calling into neigh_event_send() without any meta data updates as happening in __neigh_update(). Thus, to enable this use case, extend the latter with a NEIGH_UPDATE_F_USE flag where we break the NUD_PERMANENT state in particular so that a latter neigh_event_send() is able to re-resolve a neighbor entry. Before fix, NUD_PERMANENT -> NUD_* & NTF_USE: # ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT [...] # ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT [...] As can be seen, despite the admin-triggered replace, the entry remains in the NUD_PERMANENT state. After fix, NUD_PERMANENT -> NUD_* & NTF_USE: # ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT [...] # ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn REACHABLE [...] # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn STALE [...] # ./ip/ip n replace 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a PERMANENT [...] After the fix, the admin-triggered replace switches to a dynamic state from the NTF_USE flag which triggered a new neighbor resolution. Likewise, we can transition back from there, if needed, into NUD_PERMANENT. Similar before/after behavior can be observed for below transitions: Before fix, NTF_USE -> NTF_USE | NTF_EXT_LEARNED -> NTF_USE: # ./ip/ip n replace 192.168.178.30 dev enp5s0 use # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE [...] # ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE [...] After fix, NTF_USE -> NTF_USE | NTF_EXT_LEARNED -> NTF_USE: # ./ip/ip n replace 192.168.178.30 dev enp5s0 use # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE [...] # ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn REACHABLE [...] # ./ip/ip n replace 192.168.178.30 dev enp5s0 use # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE [..] Signed-off-by: Daniel Borkmann Acked-by: Roopa Prabhu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/neighbour.h | 1 + net/core/neighbour.c | 22 +++++++++++++--------- 2 files changed, 14 insertions(+), 9 deletions(-) diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 4232bc8ce3d7d..b6494e87c897c 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -253,6 +253,7 @@ static inline void *neighbour_priv(const struct neighbour *n) #define NEIGH_UPDATE_F_OVERRIDE 0x00000001 #define NEIGH_UPDATE_F_WEAK_OVERRIDE 0x00000002 #define NEIGH_UPDATE_F_OVERRIDE_ISROUTER 0x00000004 +#define NEIGH_UPDATE_F_USE 0x10000000 #define NEIGH_UPDATE_F_EXT_LEARNED 0x20000000 #define NEIGH_UPDATE_F_ISROUTER 0x40000000 #define NEIGH_UPDATE_F_ADMIN 0x80000000 diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 3a4cf53e38416..02e55041a8813 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1221,7 +1221,7 @@ static void neigh_update_hhs(struct neighbour *neigh) lladdr instead of overriding it if it is different. NEIGH_UPDATE_F_ADMIN means that the change is administrative. - + NEIGH_UPDATE_F_USE means that the entry is user triggered. NEIGH_UPDATE_F_OVERRIDE_ISROUTER allows to override existing NTF_ROUTER flag. NEIGH_UPDATE_F_ISROUTER indicates if the neighbour is known as @@ -1259,6 +1259,12 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, goto out; ext_learn_change = neigh_update_ext_learned(neigh, flags, ¬ify); + if (flags & NEIGH_UPDATE_F_USE) { + new = old & ~NUD_PERMANENT; + neigh->nud_state = new; + err = 0; + goto out; + } if (!(new & NUD_VALID)) { neigh_del_timer(neigh); @@ -1966,22 +1972,20 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, if (protocol) neigh->protocol = protocol; - if (ndm->ndm_flags & NTF_EXT_LEARNED) flags |= NEIGH_UPDATE_F_EXT_LEARNED; - if (ndm->ndm_flags & NTF_ROUTER) flags |= NEIGH_UPDATE_F_ISROUTER; + if (ndm->ndm_flags & NTF_USE) + flags |= NEIGH_UPDATE_F_USE; - if (ndm->ndm_flags & NTF_USE) { + err = __neigh_update(neigh, lladdr, ndm->ndm_state, flags, + NETLINK_CB(skb).portid, extack); + if (!err && ndm->ndm_flags & NTF_USE) { neigh_event_send(neigh, NULL); err = 0; - } else - err = __neigh_update(neigh, lladdr, ndm->ndm_state, flags, - NETLINK_CB(skb).portid, extack); - + } neigh_release(neigh); - out: return err; } -- 2.33.0