From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Klassert Subject: [PATCH 3/3] vti6: Change minimum MTU to IPV4_MIN_MTU, vti6 can carry IPv4 too Date: Mon, 7 May 2018 10:43:23 +0200 Message-ID: <20180507084323.22165-4-steffen.klassert@secunet.com> References: <20180507084323.22165-1-steffen.klassert@secunet.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Herbert Xu , Steffen Klassert , To: David Miller Return-path: Received: from a.mx.secunet.com ([62.96.220.36]:56670 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752227AbeEGIn3 (ORCPT ); Mon, 7 May 2018 04:43:29 -0400 In-Reply-To: <20180507084323.22165-1-steffen.klassert@secunet.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Stefano Brivio A vti6 interface can carry IPv4 as well, so it makes no sense to enforce a minimum MTU of IPV6_MIN_MTU. If the user sets an MTU below IPV6_MIN_MTU, IPv6 will be disabled on the interface, courtesy of addrconf_notify(). Reported-by: Xin Long Fixes: b96f9afee4eb ("ipv4/6: use core net MTU range checking") Fixes: c6741fbed6dc ("vti6: Properly adjust vti6 MTU from MTU of lower device") Fixes: 53c81e95df17 ("ip6_vti: adjust vti mtu according to mtu of lower device") Signed-off-by: Stefano Brivio Signed-off-by: Steffen Klassert --- net/ipv6/ip6_vti.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index c214ffec02f0..ca957dd93a29 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -669,7 +669,7 @@ static void vti6_link_config(struct ip6_tnl *t, bool keep_mtu) else mtu = ETH_DATA_LEN - LL_MAX_HEADER - sizeof(struct ipv6hdr); - dev->mtu = max_t(int, mtu, IPV6_MIN_MTU); + dev->mtu = max_t(int, mtu, IPV4_MIN_MTU); } /** @@ -881,7 +881,7 @@ static void vti6_dev_setup(struct net_device *dev) dev->priv_destructor = vti6_dev_free; dev->type = ARPHRD_TUNNEL6; - dev->min_mtu = IPV6_MIN_MTU; + dev->min_mtu = IPV4_MIN_MTU; dev->max_mtu = IP_MAX_MTU - sizeof(struct ipv6hdr); dev->flags |= IFF_NOARP; dev->addr_len = sizeof(struct in6_addr); -- 2.14.1