From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELs3yrGudBl9OUgxANsfGLv7fQgUuRE1vAy5G4ZstNrdG2mJwCRH5P/p4YirzCtUE7ugpAwB ARC-Seal: i=1; a=rsa-sha256; t=1521800225; cv=none; d=google.com; s=arc-20160816; b=guqxeYimFTEDVp5rI4+Cxq6cOkKS/hpVo8t3bQOHHHcvUIg3o6zKGev186p+9Hfmnt spyoHFZrqooxgRSUe+JJ8SbPEHpRpLXj8y1EQHa93rCEEXf5bneK3qBprUzWfQOSDodg QnoItUxlAQ4fVN/ldCUNyviInRhP5ZH6aPBMAs7z2nBhpKGNxw79/wafG1LPzp+qc/Kr f0IspA3f0P3U5/FC+lo88kn+kwtYS/UCYmpaTM9ztsHkglvPIs7IOPfGLPKJUe2EiUCR whRf3uJQfjOkqz0Ltdm92g04rhAB1WEuDp96N8OkynDg2mZXp2ZkuWhrZVGiWfnjT+rV cKjw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=tOf6nbK7CUFqmAaGqPxD9O3+kc+zq7ig/VJBMMhGpoU=; b=eXvuftpWsoKZ41FdfhxgxGiQ1rm6lkLmqRkzCRn4BgOiUSmMtv0m9S8CbrkxspygcX 5tDXNrfO5m8gp198S6h6GClOC7zoZRAxD8ewPYgjcIKzw1hRCZHIgUoUwTW/bjgyNAp3 xGyplXB7X4FHNgj/gCa/d2IoBQK4l+ObHNz29vEao3gfDL4NBa0Yx4T623UwIMstz23r erTNEEjPE4VYaz6WFLSFVyr2oxJaCMS6nZMuglMoYZveg/63ldKdTDoPx62h5zH8WU0k vj2ukCxv5XNcoWs6e0A7noxnQLgTBdsEKE4T9wN+HChAP25AIcbNIO8XfEDiWBeOBaoO 7omA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Petr Vorel , Alexey Kodanev , "David S. Miller" , Sasha Levin Subject: [PATCH 4.4 92/97] ip6_vti: adjust vti mtu according to mtu of lower device Date: Fri, 23 Mar 2018 10:55:19 +0100 Message-Id: <20180323094202.622913188@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180323094157.535925724@linuxfoundation.org> References: <20180323094157.535925724@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1595722029897098807?= X-GMAIL-MSGID: =?utf-8?q?1595723193798452395?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexey Kodanev [ Upstream commit 53c81e95df1793933f87748d36070a721f6cb287 ] LTP/udp6_ipsec_vti tests fail when sending large UDP datagrams over ip6_vti that require fragmentation and the underlying device has an MTU smaller than 1500 plus some extra space for headers. This happens because ip6_vti, by default, sets MTU to ETH_DATA_LEN and not updating it depending on a destination address or link parameter. Further attempts to send UDP packets may succeed because pmtu gets updated on ICMPV6_PKT_TOOBIG in vti6_err(). In case the lower device has larger MTU size, e.g. 9000, ip6_vti works but not using the possible maximum size, output packets have 1500 limit. The above cases require manual MTU setup after ip6_vti creation. However ip_vti already updates MTU based on lower device with ip_tunnel_bind_dev(). Here is the example when the lower device MTU is set to 9000: # ip a sh ltp_ns_veth2 ltp_ns_veth2@if7: mtu 9000 ... inet 10.0.0.2/24 scope global ltp_ns_veth2 inet6 fd00::2/64 scope global # ip li add vti6 type vti6 local fd00::2 remote fd00::1 # ip li show vti6 vti6@NONE: mtu 1500 ... link/tunnel6 fd00::2 peer fd00::1 After the patch: # ip li add vti6 type vti6 local fd00::2 remote fd00::1 # ip li show vti6 vti6@NONE: mtu 8832 ... link/tunnel6 fd00::2 peer fd00::1 Reported-by: Petr Vorel Signed-off-by: Alexey Kodanev Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_vti.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -614,6 +614,7 @@ static void vti6_link_config(struct ip6_ { struct net_device *dev = t->dev; struct __ip6_tnl_parm *p = &t->parms; + struct net_device *tdev = NULL; memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr)); memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr)); @@ -626,6 +627,25 @@ static void vti6_link_config(struct ip6_ dev->flags |= IFF_POINTOPOINT; else dev->flags &= ~IFF_POINTOPOINT; + + if (p->flags & IP6_TNL_F_CAP_XMIT) { + int strict = (ipv6_addr_type(&p->raddr) & + (IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL)); + struct rt6_info *rt = rt6_lookup(t->net, + &p->raddr, &p->laddr, + p->link, strict); + + if (rt) + tdev = rt->dst.dev; + ip6_rt_put(rt); + } + + if (!tdev && p->link) + tdev = __dev_get_by_index(t->net, p->link); + + if (tdev) + dev->mtu = max_t(int, tdev->mtu - dev->hard_header_len, + IPV6_MIN_MTU); } /**