From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hangbin Liu Subject: [PATCH net] ipvlan: call dev_change_flags when reset ipvlan mode Date: Mon, 18 Jun 2018 22:04:37 +0800 Message-ID: <1529330677-15328-1-git-send-email-liuhangbin@gmail.com> Cc: Stefano Brivio , Paolo Abeni , David Miller , Mahesh Bandewar , Hangbin Liu To: netdev@vger.kernel.org Return-path: Received: from mail-pf0-f193.google.com ([209.85.192.193]:38711 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754321AbeFROE6 (ORCPT ); Mon, 18 Jun 2018 10:04:58 -0400 Received: by mail-pf0-f193.google.com with SMTP id b74-v6so8230119pfl.5 for ; Mon, 18 Jun 2018 07:04:57 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: After we change the ipvlan mode from l3 to l2, or vice versa. We only reset IFF_NOARP flag, but don't flush the ARP table cache, which will cause eth->h_dest to be equal to eth->h_source in ipvlan_xmit_mode_l2(). Then the message will not come out of host. Here is the reproducer on local host: ip link set eth1 up ip addr add 192.168.1.1/24 dev eth1 ip link add link eth1 ipvlan1 type ipvlan mode l3 ip netns add net1 ip link set ipvlan1 netns net1 ip netns exec net1 ip link set ipvlan1 up ip netns exec net1 ip addr add 192.168.2.1/24 dev ipvlan1 ip route add 192.168.2.0/24 via 192.168.1.2 ping 192.168.2.2 -c 2 ip netns exec net1 ip link set ipvlan1 type ipvlan mode l2 ping 192.168.2.2 -c 2 Add the same configuration on remote host. After we set the mode to l2, we could find that the src/dst MAC addresses are the same on eth1: 21:26:06.648565 00:b7:13:ad:d3:05 > 00:b7:13:ad:d3:05, ethertype IPv4 (0x0800), length 98: (tos 0x0, ttl 64, id 58356, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.2.1 > 192.168.2.2: ICMP echo request, id 22686, seq 1, length 64 Fix this by calling dev_change_flags(), which will call netdevice notifier with flag change info. Reported-by: Jianlin Shi Reviewed-by: Stefano Brivio Fixes: 2ad7bf3638411 ("ipvlan: Initial check-in of the IPVLAN driver.") Signed-off-by: Hangbin Liu --- drivers/net/ipvlan/ipvlan_main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c index 4377c26..368712b 100644 --- a/drivers/net/ipvlan/ipvlan_main.c +++ b/drivers/net/ipvlan/ipvlan_main.c @@ -75,6 +75,7 @@ static int ipvlan_set_port_mode(struct ipvl_port *port, u16 nval) { struct ipvl_dev *ipvlan; struct net_device *mdev = port->dev; + unsigned int flags; int err = 0; ASSERT_RTNL(); @@ -94,10 +95,13 @@ static int ipvlan_set_port_mode(struct ipvl_port *port, u16 nval) mdev->l3mdev_ops = NULL; } list_for_each_entry(ipvlan, &port->ipvlans, pnode) { + flags = ipvlan->dev->flags; if (nval == IPVLAN_MODE_L3 || nval == IPVLAN_MODE_L3S) - ipvlan->dev->flags |= IFF_NOARP; + dev_change_flags(ipvlan->dev, + flags | IFF_NOARP); else - ipvlan->dev->flags &= ~IFF_NOARP; + dev_change_flags(ipvlan->dev, + flags & ~IFF_NOARP); } port->mode = nval; } -- 2.5.5