4.17-stable review patch. If anyone has any objections, please let me know.
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From: Hangbin Liu liuhangbin@gmail.com
[ Upstream commit 5dc2d3996a8b221c20dd0900bdad45031a572530 ]
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.
v2: a) As pointed out by Wang Cong, check return value for dev_change_flags() when change dev flags. b) As suggested by Stefano and Sabrina, move flags setting before l3mdev_ops. So we don't need to redo ipvlan_{, un}register_nf_hook() again in err path.
Reported-by: Jianlin Shi jishi@redhat.com Reviewed-by: Stefano Brivio sbrivio@redhat.com Reviewed-by: Sabrina Dubroca sd@queasysnail.net Fixes: 2ad7bf3638411 ("ipvlan: Initial check-in of the IPVLAN driver.") Signed-off-by: Hangbin Liu liuhangbin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ipvlan/ipvlan_main.c | 36 ++++++++++++++++++++++++++++-------- 1 file changed, 28 insertions(+), 8 deletions(-)
--- a/drivers/net/ipvlan/ipvlan_main.c +++ b/drivers/net/ipvlan/ipvlan_main.c @@ -75,10 +75,23 @@ static int ipvlan_set_port_mode(struct i { struct ipvl_dev *ipvlan; struct net_device *mdev = port->dev; - int err = 0; + unsigned int flags; + int err;
ASSERT_RTNL(); if (port->mode != nval) { + list_for_each_entry(ipvlan, &port->ipvlans, pnode) { + flags = ipvlan->dev->flags; + if (nval == IPVLAN_MODE_L3 || nval == IPVLAN_MODE_L3S) { + err = dev_change_flags(ipvlan->dev, + flags | IFF_NOARP); + } else { + err = dev_change_flags(ipvlan->dev, + flags & ~IFF_NOARP); + } + if (unlikely(err)) + goto fail; + } if (nval == IPVLAN_MODE_L3S) { /* New mode is L3S */ err = ipvlan_register_nf_hook(read_pnet(&port->pnet)); @@ -86,21 +99,28 @@ static int ipvlan_set_port_mode(struct i mdev->l3mdev_ops = &ipvl_l3mdev_ops; mdev->priv_flags |= IFF_L3MDEV_MASTER; } else - return err; + goto fail; } else if (port->mode == IPVLAN_MODE_L3S) { /* Old mode was L3S */ mdev->priv_flags &= ~IFF_L3MDEV_MASTER; ipvlan_unregister_nf_hook(read_pnet(&port->pnet)); mdev->l3mdev_ops = NULL; } - list_for_each_entry(ipvlan, &port->ipvlans, pnode) { - if (nval == IPVLAN_MODE_L3 || nval == IPVLAN_MODE_L3S) - ipvlan->dev->flags |= IFF_NOARP; - else - ipvlan->dev->flags &= ~IFF_NOARP; - } port->mode = nval; } + return 0; + +fail: + /* Undo the flags changes that have been done so far. */ + list_for_each_entry_continue_reverse(ipvlan, &port->ipvlans, pnode) { + flags = ipvlan->dev->flags; + if (port->mode == IPVLAN_MODE_L3 || + port->mode == IPVLAN_MODE_L3S) + dev_change_flags(ipvlan->dev, flags | IFF_NOARP); + else + dev_change_flags(ipvlan->dev, flags & ~IFF_NOARP); + } + return err; }