From patchwork Mon Nov 9 02:50:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Dike X-Patchwork-Id: 322105 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 ABF0AC2D0A3 for ; Mon, 9 Nov 2020 03:49:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 472DF22244 for ; Mon, 9 Nov 2020 03:49:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=akamai.com header.i=@akamai.com header.b="chK/xoOG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729107AbgKIDtI (ORCPT ); Sun, 8 Nov 2020 22:49:08 -0500 Received: from mx0a-00190b01.pphosted.com ([67.231.149.131]:60658 "EHLO mx0a-00190b01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728802AbgKIDtI (ORCPT ); Sun, 8 Nov 2020 22:49:08 -0500 Received: from pps.filterd (m0122332.ppops.net [127.0.0.1]) by mx0a-00190b01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0A92hI8f018286; Mon, 9 Nov 2020 02:51:55 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=akamai.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=jan2016.eng; bh=tAITiyXWbw2rwdSal74lKow8tHI1ntez5QMB6aYZyYs=; b=chK/xoOGVOTh4yfpPFu54Ti3/b2aepGueSMemNTzyTkUOrSsFN8PypRJcGrKWU7Aai9m 0y3D8mUPSlKvpP3NkdFDoJfgbmAPoui1lu/kVeyX9lr9XJ7PioRkvbUmk3Dex9NWUHII 2hKedNWLlIyu3zLqQr+gApeeoGd7jT7/1eFg1MhVP++1bpPKX4JnDuxSsHpglaAL/rkY /vFAWsbHspkOeaw6bk2fuZTvG/DrHucMFJ+trLwdrIZCGRA0YZf6/7mOUEY/i3xXzFyu Ej+7BbBi5++VsN5JptJ97tWtZ1elBX0b9u/Q4FnsN3En1DdrJBjwt2Q1hAhaxZdCa0P/ yw== Received: from prod-mail-ppoint1 (prod-mail-ppoint1.akamai.com [184.51.33.18] (may be forged)) by mx0a-00190b01.pphosted.com with ESMTP id 34nmgsw1mu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 09 Nov 2020 02:51:55 +0000 Received: from pps.filterd (prod-mail-ppoint1.akamai.com [127.0.0.1]) by prod-mail-ppoint1.akamai.com (8.16.0.42/8.16.0.42) with SMTP id 0A92o2nu003092; Sun, 8 Nov 2020 21:51:54 -0500 Received: from email.msg.corp.akamai.com ([172.27.123.33]) by prod-mail-ppoint1.akamai.com with ESMTP id 34nqt3b385-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Sun, 08 Nov 2020 21:51:54 -0500 Received: from usma1ex-cas5.msg.corp.akamai.com (172.27.123.53) by usma1ex-dag3mb4.msg.corp.akamai.com (172.27.123.56) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sun, 8 Nov 2020 21:51:53 -0500 Received: from bos-lp1yy.kendall.corp.akamai.com (172.28.3.205) by usma1ex-cas5.msg.corp.akamai.com (172.27.123.53) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Sun, 8 Nov 2020 21:51:53 -0500 Received: by bos-lp1yy.kendall.corp.akamai.com (Postfix, from userid 45189) id D544815F992; Sun, 8 Nov 2020 21:51:01 -0500 (EST) From: Jeff Dike To: CC: David Ahern , Jeff Dike Subject: [PATCH net V2] Exempt multicast addresses from five-second neighbor lifetime Date: Sun, 8 Nov 2020 21:50:52 -0500 Message-ID: <20201109025052.23280-1-jdike@akamai.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312, 18.0.737 definitions=2020-11-08_12:2020-11-05,2020-11-08 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 bulkscore=0 adultscore=0 phishscore=0 suspectscore=1 mlxscore=0 malwarescore=0 mlxlogscore=947 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011090016 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312, 18.0.737 definitions=2020-11-08_12:2020-11-05,2020-11-08 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 bulkscore=0 priorityscore=1501 suspectscore=1 phishscore=0 impostorscore=0 mlxlogscore=934 clxscore=1015 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011090015 X-Agari-Authentication-Results: mx.akamai.com; spf=${SPFResult} (sender IP is 184.51.33.18) smtp.mailfrom=jdike@akamai.com smtp.helo=prod-mail-ppoint1 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Commit 58956317c8de ("neighbor: Improve garbage collection") guarantees neighbour table entries a five-second lifetime. Processes which make heavy use of multicast can fill the neighour table with multicast addresses in five seconds. At that point, neighbour entries can't be GC-ed because they aren't five seconds old yet, the kernel log starts to fill up with "neighbor table overflow!" messages, and sends start to fail. This patch allows multicast addresses to be thrown out before they've lived out their five seconds. This makes room for non-multicast addresses and makes messages to all addresses more reliable in these circumstances. Signed-off-by: Jeff Dike --- include/net/neighbour.h | 1 + net/core/neighbour.c | 2 ++ net/ipv4/arp.c | 6 ++++++ net/ipv6/ndisc.c | 7 +++++++ 4 files changed, 16 insertions(+) diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 81ee17594c32..22ced1381ede 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -204,6 +204,7 @@ struct neigh_table { int (*pconstructor)(struct pneigh_entry *); void (*pdestructor)(struct pneigh_entry *); void (*proxy_redo)(struct sk_buff *skb); + int (*is_multicast)(const void *pkey); bool (*allow_add)(const struct net_device *dev, struct netlink_ext_ack *extack); char *id; diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 8e39e28b0a8d..9500d28a43b0 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -235,6 +235,8 @@ static int neigh_forced_gc(struct neigh_table *tbl) write_lock(&n->lock); if ((n->nud_state == NUD_FAILED) || + (tbl->is_multicast && + tbl->is_multicast(n->primary_key)) || time_after(tref, n->updated)) remove = true; write_unlock(&n->lock); diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 687971d83b4e..b69bd78cfdf6 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -125,6 +125,7 @@ static int arp_constructor(struct neighbour *neigh); static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb); static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb); static void parp_redo(struct sk_buff *skb); +static int arp_is_multicast(const void *pkey); static const struct neigh_ops arp_generic_ops = { .family = AF_INET, @@ -156,6 +157,7 @@ struct neigh_table arp_tbl = { .key_eq = arp_key_eq, .constructor = arp_constructor, .proxy_redo = parp_redo, + .is_multicast = arp_is_multicast, .id = "arp_cache", .parms = { .tbl = &arp_tbl, @@ -928,6 +930,10 @@ static void parp_redo(struct sk_buff *skb) arp_process(dev_net(skb->dev), NULL, skb); } +static int arp_is_multicast(const void *pkey) +{ + return IN_MULTICAST(htonl(*((u32 *)pkey))); +} /* * Receive an arp request from the device layer. diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c index 27f29b957ee7..6aed5536fc5c 100644 --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -81,6 +81,7 @@ static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb); static int pndisc_constructor(struct pneigh_entry *n); static void pndisc_destructor(struct pneigh_entry *n); static void pndisc_redo(struct sk_buff *skb); +static int ndisc_is_multicast(const void *pkey); static const struct neigh_ops ndisc_generic_ops = { .family = AF_INET6, @@ -115,6 +116,7 @@ struct neigh_table nd_tbl = { .pconstructor = pndisc_constructor, .pdestructor = pndisc_destructor, .proxy_redo = pndisc_redo, + .is_multicast = ndisc_is_multicast, .allow_add = ndisc_allow_add, .id = "ndisc_cache", .parms = { @@ -1706,6 +1708,11 @@ static void pndisc_redo(struct sk_buff *skb) kfree_skb(skb); } +static int ndisc_is_multicast(const void *pkey) +{ + return (((struct in6_addr *)pkey)->in6_u.u6_addr8[0] & 0xf0) == 0xf0; +} + static bool ndisc_suppress_frag_ndisc(struct sk_buff *skb) { struct inet6_dev *idev = __in6_dev_get(skb->dev);